TY - CONF TI - Large-area, flexible, integrable and transparent DEAs for haptics AU - Ankit, Ankit AU - Chan, Jun Yu AU - Nguyen, Linh Lan AU - Krisnadi, Febby AU - Mathews, Nripan AB - With the focus on providing a sense of touch in robots, enabling feedback in virtual reality (VR) and augmented reality (AR) environment, telerobotics, remote sensing and improving user experience with touch sensitive devices like display kiosks and smartphones, haptic interfaces have become critical as they can convey information quickly. A human hand can feel different physical parameters such as roughness, softness and vibration and discern them as textures of the surface. Most of the technologies being employed for haptic feedback currently rely on simulating the perception of texture change, however few of the technologies like microfluidics and electroactive polymers (EAPs) can create actual topographical changes on the surface. Additionally, most of these haptic devices are opaque and they often serve as mere touchpads whilst the visual component of the simulation is projected elsewhere, so the user appears to interact with the simulated object indirectly. Dielectric elastomer actuators (DEAs), an EAP, is of peculiar interest owing to their characteristics like large actuation strains, facile fabrication, low costs of manufacturing and low power consumption. Herein, we demonstrate a large area, transparent tactile feedback device with 4 individually controlled active regions, that can be integrated onto electronic displays to provide unobstructed topographic texture change. We fabricate the device in a unique architecture, with the elastomeric layer, compliant electrodes, and the soft passive layer as all transparent materials. These devices show high transparency of over 70% in the visible region of the spectrum, and surface deformation of ~165 μm. C2 - 2019/3/13/ C3 - Electroactive Polymer Actuators and Devices (EAPAD) XXI DA - 2019/3/13/ DO - 10.1117/12.2514267 UR - http://dx.doi.org/10.1117/12.2514267 ER - TY - CONF TI - Chemical Engineering Student Moral Reasoning within Hypothetical Process Safety Contexts AU - Anastasio, D. AU - Bodnar, C. AU - Cooper, M. AU - Burkey, D. AU - Stransky, J. T2 - AIChE National Meeting C2 - 2019/// C3 - AIChE National Meeting CY - Orlando, FL DA - 2019/// PY - 2019/// ER - TY - CONF TI - Immersive Digital Experiences for Process Safety Decision Making AU - Bodnar, C. AU - Cooper, M. AU - Burkey, D. AU - Anastasio, D. T2 - AIChE National Meeting C2 - 2019/// C3 - AIChE National Meeting CY - Orlando, FL DA - 2019/// PY - 2019/// ER - TY - SOUND TI - Digital Experiences in Chemical Engineering and Process Safety AU - Cooper, M. DA - 2019/// PY - 2019/// M3 - Seminar PB - University of Florida ER - TY - CONF TI - The Path Less Traveled: Professional Development for Non-Tenure Track Faculty AU - Cooper, M. T2 - AIChE National Meeting C2 - 2019/// C3 - AIChE National Meeting CY - Orlando, FL DA - 2019/// PY - 2019/// ER - TY - CONF TI - You Can Do It! Overcoming Common Challenges in Engineering Education Research AU - Cooper, M. AU - Koretsky, M. T2 - AIChE National Meeting C2 - 2019/// C3 - AIChE National Meeting CY - Orlando, FL DA - 2019/// PY - 2019/// ER - TY - JOUR TI - Students Are a Lot Like... Tomatoes AU - Cooper, M. T2 - Chemical Engineering Education DA - 2019/// PY - 2019/// VL - 53 IS - 1 SP - 55 ER - TY - JOUR TI - Microfluidic Technologies for High Throughput Screening Through Sorting and On-Chip Culture of C. elegans AU - Midkiff, Daniel AU - Miguel, Adriana San T2 - Molecules AB - The nematode Caenorhabditis elegans is a powerful model organism that has been widely used to study molecular biology, cell development, neurobiology, and aging. Despite their use for the past several decades, the conventional techniques for growth, imaging, and behavioral analysis of C. elegans can be cumbersome, and acquiring large data sets in a high-throughput manner can be challenging. Developments in microfluidic “lab-on-a-chip” technologies have improved studies of C. elegans by increasing experimental control and throughput. Microfluidic features such as on-chip control layers, immobilization channels, and chamber arrays have been incorporated to develop increasingly complex platforms that make experimental techniques more powerful. Genetic and chemical screens are performed on C. elegans to determine gene function and phenotypic outcomes of perturbations, to test the effect that chemicals have on health and behavior, and to find drug candidates. In this review, we will discuss microfluidic technologies that have been used to increase the throughput of genetic and chemical screens in C. elegans. We will discuss screens for neurobiology, aging, development, behavior, and many other biological processes. We will also discuss robotic technologies that assist in microfluidic screens, as well as alternate platforms that perform functions similar to microfluidics. DA - 2019/11// PY - 2019/11// DO - 10.3390/molecules24234292 UR - https://www.mdpi.com/1420-3049/24/23/4292 ER - TY - JOUR TI - Protecting the Nanoscale Properties of Ag Nanowires with a Solution-Grown SnO2 Monolayer as Corrosion Inhibitor AU - Zhao, Yang AU - Wang, Xijun AU - Yang, Shize AU - Kuttner, Elisabeth AU - Taylor, Aidan A. AU - Salemmilani, Reza AU - Liu, Xin AU - Moskovits, Martin AU - Wu, Binghui AU - Dehestani, Ahmad AU - Li, Jian-Feng AU - Chisholm, Matthew F. AU - Tian, Zhong-Qun AU - Fan, Feng-Ru AU - Jiang, Jun AU - Stucky, Galen D. T2 - Journal of the American Chemical Society AB - The chemical reactivity and/or the diffusion of Ag atoms or ions during thermal processing can cause irreversible structural damage, hindering the application of Ag nanowires (NWs) in transparent conducting films and other applications that make use of the material’s nanoscale properties. Here, we describe a simple and effective method for growing monolayer SnO2 on the surface of Ag nanowires under ambient conditions, which protects the Ag nanowires from chemical and structural damage. Our results show that Sn2+ and Ag atoms undergo a redox reaction in the presence of water. First-principle simulations suggest a reasonable mechanism for SnO2 formation, showing that the interfacial polarization of the silver by the SnO2 can significantly reduce the affinity of Ag to O2, thereby greatly reducing the oxidation of the silver. The corresponding values (for example, before coating: 17.2 Ω/sq at 86.4%, after coating: 19.0 Ω/sq at 86.6%) show that the deposition of monolayer SnO2 enables the preservation of high transparency and conductivity of Ag. In sharp contrast to the large-scale degradation of pure Ag-NW films including the significant reduction of its electrical conductivity when subjected to a series of harsh corrosion environments, monolayer SnO2 coated Ag-NW films survive structurally and retain their electrical conductivity. Consequently, the thermal, electrical, and chemical stability properties we report here, and the simplicity of the technology used to achieve them, are among the very best reported for transparent conductor materials to date. DA - 2019/9/4/ PY - 2019/9/4/ DO - 10.1021/jacs.9b07172 VL - 141 IS - 35 SP - 13977-13986 UR - https://doi.org/10.1021/jacs.9b07172 ER - TY - JOUR TI - Protecting Single Atom Catalysts with Graphene/Carbon-Nitride “Chainmail” AU - Yang, Tongtong AU - Huang, Yan AU - Yang, Li AU - Li, Xiyu AU - Wang, Xijun AU - Zhang, Guozhen AU - Luo, Yi AU - Jiang, Jun T2 - The Journal of Physical Chemistry Letters AB - Single-atom catalysts (SACs) possess high chemical activity but suffer from structural vulnerability owing to atom aggregation or attacks from reaction intermediates. In this work, we employed first-principles simulations to propose a design of stable and efficient transition-metal (TM) SAC protected by graphene or carbon-nitride "chainmail". We found that a single TM atom can be strongly anchored between two graphene (GR) or GR-C3N layers, forming stable sandwich structures of GR-TM-GR and C3N-TM-GR. By donating electrons to the nearby atoms of GR/C3N, TMs pass on their high catalytic activities to the chainmail. For instance, the hydrogen evolution reaction catalyzed by the single-atom Cu with C3N chainmail exhibits almost zero free energy barrier (∼0.01 eV), which outperforms commercial Pt catalyst (∼0.09 eV). Importantly, such graphene/carbon-nitride chainmail can prevent SAC TM atoms from aggregating, as well as prevent attacks of reaction intermediates. This suggests an alternative way of managing high stability and activity for SAC systems simultaneously toward practical utilization. DA - 2019/6/6/ PY - 2019/6/6/ DO - 10.1021/acs.jpclett.9b01336 VL - 10 IS - 11 SP - 3129-3133 UR - https://doi.org/10.1021/acs.jpclett.9b01336 ER - TY - JOUR TI - Physically Close yet Chemically Separate Reduction and Oxidation Sites in Double-Walled Nanotubes for Photocatalytic Hydrogen Generation AU - Yang, Li AU - Li, Xin AU - Huang, Yan AU - Feng, Shuo AU - Wang, Xijun AU - Jiang, Xiang AU - Li, Xiyu AU - Zhao, Jin AU - Luo, Yi AU - Zhang, Guozhen AU - Jiang, Jun T2 - The Journal of Physical Chemistry Letters AB - The localization of photoexcitation leads to the proximity of photocatalytic reduction and oxidation sites, causing unfavorable side reactions. To address this issue, we designed a double-walled nanotube model system consisting of carbon nanotube (CNT) outside and carbon-nitride nanotube (CNNT) inside, with physically close yet chemically separate reduction and oxidation sites for safe photocatalytic hydrogen generation. First-principle calculations show that photoexcited charges in the system rapidly separate, leaving electrons at the reductive sites in CNNT and holes at the oxidative sites in CNT, respectively. Then protons generated by hole-assisted water dissociation at the CNT migrate to the CNNT and are reduced, producing H2. The selective permeability of protons through CNT ensures complete separation of hydrogen molecules and oxygen species, and thereby the reduction and oxidation half-reactions. Further, H2 products can be delivered via the double-walled nanotube for safe collection. The seamless integration of photocatalytic hydrogen generation and delivery in one system provides an alternative solution toward practical solar-driven hydrogen utilization. DA - 2019/7/5/ PY - 2019/7/5/ DO - 10.1021/acs.jpclett.9b01722 VL - 10 IS - 13 SP - 3739-3743 UR - https://doi.org/10.1021/acs.jpclett.9b01722 ER - TY - JOUR TI - Metal-enhanced hydrogenation of graphene with atomic pattern AU - Wang, Xijun AU - Zhang, Guozhen AU - Wang, Zhaowu AU - Yang, Li AU - Li, Xiyu AU - Jiang, Jun AU - Luo, Yi T2 - Carbon AB - Abstract Graphene hydrogenation is an attractive approach to functionalize graphene. However, the hydrogenating treatment could only be achieved under harsh conditions due to the weak hydrogen affinity of graphene. It has also made the direct writing of electronic circuits on graphene by hydrogenation very difficult. Here we propose a metal-enhanced approach to hydrogenate graphene with atomic pattern that enables to produce hydrogenation pattern on demand. First-principles calculations reveal that certain metals (Cu, Ag, Al) attached to graphene can significantly lower the energy barrier for hydrogen binding process, while the hydrogen binding energy itself is much enhanced. Such metal-promoted hydrogenation is spatially localized, which paves the way to precisely write pre-designed hydrogenation patterns on graphene with well-controlled metallic clusters and tips. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.carbon.2018.11.080 VL - 143 SP - 700-705 UR - https://doi.org/10.1016/j.carbon.2018.11.080 ER - TY - JOUR TI - Immobilizing copper-supported graphene with surface hydrogenation or hydroxylation: A first-principle study AU - Li, Leilei AU - Yang, Li AU - Wang, Xijun AU - Ni, Yong AU - Jiang, Jun AU - Zhang, Guozhen T2 - Chemical Physics AB - Applications of graphene requires deposition on a proper solid support. Yet it suffers from the mechanical instability issue owing to appreciable mobility of graphene on the surface. We conducted a first-principle study and found either hydrogenation or hydroxylation of graphene can effectively fix its position on Cu(1 1 1) surface. We computed the variation of binding energy and stacking fault energy. Comparing to the graphene-Cu(1 1 1) stack which shifts easily with low energy barrier, the hydrogenated or hydroxylated graphene on Cu(1 1 1) are mechanically stable due to high energy requirements to induce geometric variations to the optimized stacking configurations. Such immobilization effect is ascribed to the strong couplings between chemically modified graphene and Cu(1 1 1), as suggested by effective charge polarizations at interfaces. It is found that the immobilization effect can help increase the Pt loading on graphene. Our study suggests that hydrogenation or hydroxylation of graphene can be helpful for developing stable graphene-derived materials. DA - 2019/7// PY - 2019/7// DO - 10.1016/j.chemphys.2019.04.019 VL - 523 SP - 183-190 ER - TY - JOUR TI - Correction to “Protecting Single Atom Catalysts with Graphene/Carbon-Nitride “Chainmail”” AU - Yang, Tongtong AU - Huang, Yan AU - Yang, Li AU - Li, Xiyu AU - Wang, Xijun AU - Zhang, Guozhen AU - Luo, Yi AU - Jiang, Jun T2 - The Journal of Physical Chemistry Letters AB - ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Protecting Single Atom Catalysts with Graphene/Carbon-Nitride “Chainmail””Tongtong YangTongtong YangMore by Tongtong Yang, Yan HuangYan HuangMore by Yan Huang, Li YangLi YangMore by Li Yang, Xiyu LiXiyu LiMore by Xiyu Li, Xijun WangXijun WangMore by Xijun Wanghttp://orcid.org/0000-0001-9155-7653, Guozhen ZhangGuozhen ZhangMore by Guozhen Zhanghttp://orcid.org/0000-0003-0125-9666, Yi LuoYi LuoMore by Yi Luo, and Jun Jiang*Jun JiangMore by Jun Jianghttp://orcid.org/0000-0002-6116-5605Cite this: J. Phys. Chem. Lett. 2019, 10, 20, 6088Publication Date (Web):September 30, 2019Publication History Published online30 September 2019Published inissue 17 October 2019https://doi.org/10.1021/acs.jpclett.9b02718Copyright © 2019 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views786Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (302 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts DA - 2019/10/17/ PY - 2019/10/17/ DO - 10.1021/acs.jpclett.9b02718 VL - 10 IS - 20 SP - 6088-6088 UR - https://doi.org/10.1021/acs.jpclett.9b02718 ER - TY - JOUR TI - Catalytic Chemistry Predicted by a Charge Polarization Descriptor: Synergistic O2 Activation and CO Oxidation by Au−Cu Bimetallic Clusters on TiO2(101) AU - Jia, Chuanyi AU - Wang, Xijun AU - Zhong, Wenhui AU - Wang, Zhunzhun AU - Prezhdo, Oleg V. AU - Luo, Yi AU - Jiang, Jun T2 - ACS Applied Materials & Interfaces AB - The versatile properties of bimetallic nanoparticles greatly expand the range of catalyzed chemical reactions. We demonstrate that surface chemistry can be understood and predicted using a simple adsorbate–surface interaction descriptor that relates charge polarization to chemical reactivity. Our density functional theory studies of O2 activation and CO oxidation catalyzed by Au7–Cu1 bimetallic nanoparticles supported on the TiO2(101) surface demonstrate that the generated oxidized Cu atom (CuOx) can efficiently inhibit the aggregation of the active Cu sites. Moreover, because of the strong dipole–dipole interaction between the surface and the adsorbate on the oxidized Cu site, the adsorption of CO + O2/CO + O can be significantly enhanced, which can decrease the CO oxidation barriers and further improve catalytic performance. The product of the two electric dipole moments provides a parameter that allows us to predict the key catalytic properties for different adsorption sites and reaction pathways. The reported findings provide important insights into the mechanism of chemical reactivity of metallic clusters and generate a valuable principle for catalyst design. DA - 2019/2/11/ PY - 2019/2/11/ DO - 10.1021/acsami.9b00925 VL - 2 IS - 9 SP - 9629-9640 UR - https://doi.org/10.1021/acsami.9b00925 ER - TY - JOUR TI - Bimetallic Pd/Co Embedded in Two-Dimensional Carbon-Nitride for Z-Scheme Photocatalytic Water Splitting AU - Xie, Liyan AU - Li, Xiyu AU - Wang, Xijun AU - Ge, Wanying AU - Zhang, Jinxiao AU - Jiang, Jun AU - Zhang, Guozhen T2 - The Journal of Physical Chemistry C AB - Two-dimensional s-triazine-based graphitic carbon nitride (g-CN) material with a band gap of 3.18 eV has emerged as a promising photocatalyst for water splitting. Here, we propose a Z-scheme photocatalyst by embedding Pd(OH)2– and Co(OH)2– groups in different parts of g-CN simultaneously. Density functional theory calculations show that it extends solar light absorption of g-CN into visible and infrared regions, realizes efficient charge separation, and can catalyze water splitting to produce O2 and H2, respectively. The staggered band alignment meets the requirement of the Z-scheme. Importantly, ab initio nonadiabatic molecular dynamics simulations suggest that the photogenerated hole evolution accords with anticipation for subsequent water-splitting reactions. The computed Gibbs-free energy and overpotentials confirm the feasibility of hydrogen evolution reactions on the Co-centered fragment and oxygen evolution reactions on the Pd-centered fragment, respectively. It is expected that this new Z-scheme model designed on a single material platform may provide an alternative way for achieving efficient photodriven water splitting. DA - 2019/1/24/ PY - 2019/1/24/ DO - 10.1021/acs.jpcc.8b10521 VL - 123 IS - 3 SP - 1846-1851 UR - https://doi.org/10.1021/acs.jpcc.8b10521 ER - TY - JOUR TI - Bandgap tuning of C3N monolayer: A first-principles study AU - Xie, Liyan AU - Yang, Li AU - Ge, Wanying AU - Wang, Xijun AU - Jiang, Jun T2 - Chemical Physics AB - The newly found graphene-like material C3N exhibits great potential in a variety of important applications, due to its unique topological and electronic structures. To extend the utilization, a crucial challenge is to make its intrinsic bandgap (1.03 eV) tunable. Here we performed first-principles calculations to investigate the band structure variations of C3N monolayer under various surface modification treatments, including defect engineering, surface decoration and substitutional doping. Results show that those treatments can induce impurity states, orbital rehybridization, and n- or p-type doping simultaneously, and therefore enable effective band structure adjustment. Importantly, some linear relationships between the bandgap and doping concentration are revealed, paving the way for precise control of C3N bandgap. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.chemphys.2019.01.009 VL - 520 SP - 40-46 UR - https://doi.org/10.1016/j.chemphys.2019.01.009 ER - TY - JOUR TI - Isolating hydrogen from oxygen in photocatalytic water splitting with a carbon-quantum-dot/carbon-nitride hybrid AU - Wang, Xijun AU - Jiang, Xiang AU - Sharman, Edward AU - Yang, Li AU - Li, Xiyu AU - Zhang, Guozhen AU - Zhao, Jin AU - Luo, Yi AU - Jiang, Jun T2 - Journal of Materials Chemistry A AB - The practical utilization of solar-driven water splitting is restricted by the difficulty of this type of splitting in producing hydrogen and oxygen products with the same photocatalyst. DA - 2019/// PY - 2019/// DO - 10.1039/C9TA00673G VL - 7 IS - 11 SP - 6143-6148 UR - https://doi.org/10.1039/C9TA00673G ER - TY - JOUR TI - Correction to “Protecting the Nanoscale Properties of Ag Nanowires with a Solution-Grown SnO2 Monolayer as Corrosion Inhibitor” AU - Zhao, Yang AU - Wang, Xijun AU - Yang, Shize AU - Kuttner, Elisabeth AU - Taylor, Aidan A. AU - Salemmilani, Reza AU - Liu, Xin AU - Moskovits, Martin AU - Wu, Binghui AU - Dehestani, Ahmad AU - Li, Jian-Feng AU - Chisholm, Matthew F. AU - Tian, Zhong-Qun AU - Fan, Feng-Ru AU - Jiang, Jun AU - Stucky, Galen D. T2 - Journal of the American Chemical Society AB - ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Protecting the Nanoscale Properties of Ag Nanowires with a Solution-Grown SnO2 Monolayer as Corrosion Inhibitor”Yang ZhaoYang ZhaoMore by Yang Zhao, Xijun WangXijun WangMore by Xijun Wanghttp://orcid.org/0000-0001-9155-7653, Shize YangShize YangMore by Shize Yanghttp://orcid.org/0000-0002-0421-006X, Elisabeth KuttnerElisabeth KuttnerMore by Elisabeth Kuttner, Aidan A. TaylorAidan A. TaylorMore by Aidan A. Taylor, Reza SalemmilaniReza SalemmilaniMore by Reza Salemmilanihttp://orcid.org/0000-0003-1152-6828, Xin LiuXin LiuMore by Xin Liu, Martin MoskovitsMartin MoskovitsMore by Martin Moskovitshttp://orcid.org/0000-0002-0212-108X, Binghui WuBinghui WuMore by Binghui Wuhttp://orcid.org/0000-0003-4015-9991, Ahmad DehestaniAhmad DehestaniMore by Ahmad Dehestani, Jian-Feng LiJian-Feng LiMore by Jian-Feng Lihttp://orcid.org/0000-0003-1598-6856, Matthew F. ChisholmMatthew F. ChisholmMore by Matthew F. Chisholm, Zhong-Qun TianZhong-Qun TianMore by Zhong-Qun Tianhttp://orcid.org/0000-0002-9775-8189, Feng-Ru Fan*Feng-Ru FanMore by Feng-Ru Fanhttp://orcid.org/0000-0001-6474-471X, Jun Jiang*Jun JiangMore by Jun Jianghttp://orcid.org/0000-0002-6116-5605, and Galen D. Stucky*Galen D. StuckyMore by Galen D. Stuckyhttp://orcid.org/0000-0002-0837-5961Cite this: J. Am. Chem. Soc. 2019, 141, 44, 17950Publication Date (Web):October 25, 2019Publication History Published online25 October 2019Published inissue 6 November 2019https://doi.org/10.1021/jacs.9b11200Copyright © 2019 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1929Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (368 KB) Get e-Alerts Get e-Alerts DA - 2019/11/6/ PY - 2019/11/6/ DO - 10.1021/jacs.9b11200 VL - 141 IS - 44 SP - 17950-17950 UR - https://doi.org/10.1021/jacs.9b11200 ER - TY - JOUR TI - Ohmic contact formation mechanisms of TiN film on 4H–SiC T2 - Ceramics International AB - The atomic structure, interfacial charge distribution, bonding nature, and interfacial electronic states of a 4H–SiC/TiN interface are systematically investigated to understand the Ohmic contact formation mechanisms of TiN to 4H–SiC. The experiment results clearly demonstrate that the well-arranged TiN (111)-oriented lattice planes are parallel to the (0001) SiC-oriented substrate, which is in line with the XRD results. In addition, the interface is coherent without any secondary phase layers, amorphous layers, or transition regions, which confirms the direct contact of TiN to SiC at the atomic scale, exhibiting a linear current–voltage relationship. Quantitatively, first-principle calculations reveal that the Schottky barrier height (SBH) is as low as 0.03 eV and that the band gap nearly vanishes at the interface, indicating an excellent Ohmic contact of TiN to 4H–SiC. Furthermore, the SBH is significantly reduced through the interfacial charge polarization effect and strong coupling of interfacial electronic states, enhancing the quantum electron transport. The present results provide insight into the complicated electronic effects of the Ohmic contact interface and indicate that TiN is a promising SiC Ohmic contact material for advanced next-generation power device applications. DA - 2019/11// PY - 2019/11// DO - 10.1016/j.ceramint.2019.11.206 UR - http://dx.doi.org/10.1016/j.ceramint.2019.11.206 ER - TY - JOUR TI - Distributed control and optimization of process system networks: A review and perspective AU - Tang, Wentao AU - Daoutidis, Prodromos T2 - Chinese Journal of Chemical Engineering AB - Large-scale and complex process systems are essentially interconnected networks. The automated operation of such process networks requires the solution of control and optimization problems in a distributed manner. In this approach, the network is decomposed into several subsystems, each of which is under the supervision of a corresponding computing agent (controller, optimizer). The agents coordinate their control and optimization decisions based on information communication among them. In recent years, algorithms and methods for distributed control and optimization are undergoing rapid development. In this paper, we provide a comprehensive, up-to-date review with perspectives and discussions on possible future directions. DA - 2019/7// PY - 2019/7// DO - 10.1016/j.cjche.2018.08.027 VL - 27 IS - 7 SP - 1461-1473 J2 - Chinese Journal of Chemical Engineering LA - en OP - SN - 1004-9541 UR - http://dx.doi.org/10.1016/j.cjche.2018.08.027 DB - Crossref ER - TY - JOUR TI - Decomposition of control and optimization problems by network structure: Concepts, methods, and inspirations from biology AU - Daoutidis, Prodromos AU - Tang, Wentao AU - Allman, Andrew T2 - AIChE Journal AB - AIChE JournalVolume 65, Issue 10 e16708 PERSPECTIVE Decomposition of control and optimization problems by network structure: Concepts, methods, and inspirations from biology Prodromos Daoutidis, Corresponding Author Prodromos Daoutidis daout001@umn.edu Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota Correspondence Prodromos Daoutidis, Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455. Email: daout001@umn.eduSearch for more papers by this authorWentao Tang, Wentao Tang Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MinnesotaSearch for more papers by this authorAndrew Allman, Andrew Allman Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MinnesotaSearch for more papers by this author Prodromos Daoutidis, Corresponding Author Prodromos Daoutidis daout001@umn.edu Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota Correspondence Prodromos Daoutidis, Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455. Email: daout001@umn.eduSearch for more papers by this authorWentao Tang, Wentao Tang Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MinnesotaSearch for more papers by this authorAndrew Allman, Andrew Allman Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MinnesotaSearch for more papers by this author First published: 27 June 2019 https://doi.org/10.1002/aic.16708Citations: 14 Funding information: University of Minnesota; National Science Foundation Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume65, Issue10October 2019e16708 RelatedInformation DA - 2019/7/8/ PY - 2019/7/8/ DO - 10.1002/aic.16708 VL - 65 IS - 10 J2 - AIChE J LA - en OP - SN - 0001-1541 1547-5905 UR - http://dx.doi.org/10.1002/aic.16708 DB - Crossref ER - TY - JOUR TI - Dissipativity learning control (DLC): A framework of input–output data-driven control AU - Tang, Wentao AU - Daoutidis, Prodromos T2 - Computers & Chemical Engineering AB - The paper addresses data-driven control based on input–output data in the absence of an underlying dynamic model. It proposes a dissipativity learning control (DLC) framework which involves the data-based learning of the dissipativity property of the control system, followed by a dissipativity-based controller design procedure. Specifically, independent component analysis and parametric distribution inference are adopted to estimate a polyhedral region of input–output trajectory samples, whose dual cone characterizes the dissipativity property; subsequently, an optimal controller in the L2 sense is designed by solving a nonlinear semidefinite programming problem. The applicability of the proposed method is demonstrated by case studies on regulating control of a polymerization reactor and tracking control of an oscillatory chemical reactor. DA - 2019/11// PY - 2019/11// DO - 10.1016/j.compchemeng.2019.106576 VL - 130 SP - 106576 J2 - Computers & Chemical Engineering LA - en OP - SN - 0098-1354 UR - http://dx.doi.org/10.1016/j.compchemeng.2019.106576 DB - Crossref ER - TY - JOUR TI - Distributed decision making for intensified process systems AU - Daoutidis, Prodromos AU - Allman, Andrew AU - Khatib, Shaaz AU - Moharir, Manjiri A AU - Palys, Matthew J AU - Pourkargar, Davood Babaei AU - Tang, Wentao T2 - Current Opinion in Chemical Engineering AB - Process intensification can afford considerable benefits with respect to economics, sustainability and/or safety but also presents increased decision making challenges with respect to computational efficiency and flexibility across multiple temporal and spatial scales. Distributed decision making, that is, localized yet coordinated decision making among constituent subsystems, is a promising approach to alleviating these challenges. Determination of these subsystems is at the heart of the distributed paradigm. This paper gives a summary of recent developments and future directions in distributed decision making for intensified systems, specifically with respect to optimization, control and monitoring, with emphasis on methods for obtaining high quality decompositions for such problems based on network theory. It also discusses integrated renewable energy and chemical production, a new and promising domain of large-scale process intensification, in the context of systems engineering challenges and opportunities. DA - 2019/9// PY - 2019/9// DO - 10.1016/j.coche.2018.12.007 VL - 25 SP - 75-81 J2 - Current Opinion in Chemical Engineering LA - en OP - SN - 2211-3398 UR - http://dx.doi.org/10.1016/j.coche.2018.12.007 DB - Crossref ER - TY - JOUR TI - DeCODe: a community-based algorithm for generating high-quality decompositions of optimization problems AU - Allman, Andrew AU - Tang, Wentao AU - Daoutidis, Prodromos T2 - Optimization and Engineering DA - 2019/6/29/ PY - 2019/6/29/ DO - 10.1007/s11081-019-09450-5 VL - 20 IS - 4 SP - 1067-1084 J2 - Optim Eng LA - en OP - SN - 1389-4420 1573-2924 UR - http://dx.doi.org/10.1007/s11081-019-09450-5 DB - Crossref ER - TY - JOUR TI - Topology Effects on Sparse Control of Complex Networks with Laplacian Dynamics AU - Constantino, Pedro H. AU - Tang, Wentao AU - Daoutidis, Prodromos T2 - Scientific Reports AB - Abstract Ease of control of complex networks has been assessed extensively in terms of structural controllability and observability, and minimum control energy criteria. Here we adopt a sparsity-promoting feedback control framework for undirected networks with Laplacian dynamics and distinct topological features. The control objective considered is to minimize the effect of disturbance signals, magnitude of control signals and cost of feedback channels. We show that depending on the cost of feedback channels, different complex network structures become the least expensive option to control. Specifically, increased cost of feedback channels favors organized topological complexity such as modularity and centralization. Thus, although sparse and heterogeneous undirected networks may require larger numbers of actuators and sensors for structural controllability, networks with Laplacian dynamics are shown to be easier to control when accounting for the cost of feedback channels. DA - 2019/6/21/ PY - 2019/6/21/ DO - 10.1038/s41598-019-45476-6 VL - 9 IS - 1 J2 - Sci Rep LA - en OP - SN - 2045-2322 UR - http://dx.doi.org/10.1038/s41598-019-45476-6 DB - Crossref ER - TY - JOUR TI - A Bilevel Programming Approach to the Convergence Analysis of Control-Lyapunov Functions AU - Tang, Wentao AU - Daoutidis, Prodromos T2 - IEEE Transactions on Automatic Control AB - This paper deals with the estimation of convergence rate and domain of attraction of control-Lyapunov functions in Lyapunov-based control. This pair of estimation problems has been considered only for input-affine systems with constraints on the input norm. In this paper, we propose a novel optimization framework to address the estimation of convergence rate and domain of attraction. Specifically, we formulate the estimation problems as min-max bilevel programs for the decay rate of the Lyapunov function, where the inner problem can be resolved using Karush-Kuhn-Tucker optimality conditions, and the resulting single-level programs can be transformed into and solved as mixed-integer nonlinear programs. The proposed approach is applicable to systems with input-nonaffinity or more general forms of input constraints under an input-convexity assumption. DA - 2019/10// PY - 2019/10// DO - 10.1109/TAC.2019.2892386 VL - 64 IS - 10 SP - 4174-4179 J2 - IEEE Trans. Automat. Contr. OP - SN - 0018-9286 1558-2523 2334-3303 UR - http://dx.doi.org/10.1109/TAC.2019.2892386 DB - Crossref ER - TY - JOUR TI - Targeted capture of Chinese hamster ovary host cell proteins: Peptide ligand binding by proteomic analysis AU - Lavoie, R. Ashton AU - Fazio, Alice AU - Williams, Taufika Islam AU - Carbonell, Ruben AU - Menegatti, Stefano T2 - BIOTECHNOLOGY AND BIOENGINEERING AB - Abstract The clearance of host cell proteins (HCPs) is of crucial importance in biomanufacturing, given their diversity in composition, structure, abundance, and occasional structural homology with the product. The current approach to HCP clearance in the manufacturing of monoclonal antibodies (mAbs) relies on product capture with Protein A followed by removal of residual HCPs in flow‐through mode using ion exchange or mixed‐mode chromatography. Recent studies have highlighted the presence of “problematic HCP” species, which are either difficult to remove (Group I), can degrade the mAb product (Group II), or trigger immunogenic reactions (Group III). To improve the clearance of these species, we developed a family of synthetic peptides that target HCPs and exhibit low binding to IgG product. In this study, these peptides were conjugated onto chromatographic resins and evaluated in terms of HCP clearance and mAb yield, using an industrial mAb‐producing CHO harvest as model supernatant. To gather detailed knowledge on the binding of individual HCPs, the unbound fractions were subjected to shotgun proteomic analysis by mass spectrometry. It was found that these peptide ligands exhibit superior HCP binding capability compared to those of the benchmark commercial resins commonly used in mAb purification. In addition, some peptide‐based resins resulted in much lower losses of product yield compared to these commercial supports. The proteomic analysis showed effective capture of many “problematic HCPs” by the peptide ligands, especially some that are weakly bound by commercial media. Collectively, these results indicate that these peptides show great promise toward the development of next‐generation adsorbents for safer and cost‐effective manufacturing of biologics. DA - 2019/// PY - 2019/// DO - 10.1002/bit.27213 KW - host cell proteins KW - monoclonal antibodies KW - polishing KW - peptide ligands KW - protein purification ER - TY - JOUR TI - Reduction Kinetics of Perovskite Oxides for Selective Hydrogen Combustion in the Context of Olefin Production AU - Dudek, Ryan B. AU - Tian, Yuan AU - Jin, Gaochen AU - Blivin, Millicent AU - Li, Fanxing T2 - ENERGY TECHNOLOGY AB - Chemical looping represents a novel approach for generating light olefins in which thermal cracking or catalytic dehydrogenation is coupled with selective hydrogen combustion (SHC) by a metal oxide redox catalyst, which enables autothermal operation, increased per‐pass conversion, and greater‐than‐equilibrium yields. Recent studies indicate that Na 2 WO 4 ‐promoted perovskite oxides are effective redox catalysts with high olefin selectivity. Herein, kinetic parameters, rates, and reaction models for the reduction of unpromoted and Na 2 WO 4 ‐promoted CaMnO 3 redox catalysts by H 2 , C 2 H 4 , and C 2 H 6 , is reported. Reduction rates of CaMnO 3 under ethylene and ethane are significantly lower than under H 2 . Model fitting of reduction kinetics show good agreement with reaction order–controlled models for CaMnO 3 reduction and predict greater oxygen site dependence and higher activation energy for CaMnO 3 reduction by C 2 H 4 as compared with H 2 . Avrami–Erofe'ev nucleation and growth models provide the best fit to the reduction of Na 2 WO 4 /CaMnO 3 in H 2 and in C 2 H 4 . After Na 2 WO 4 promotion, the reduction rate of CaMnO 3 is three orders of magnitude lower in ethylene in comparison to hydrogen, consistent with its superior selectivity to hydrogen combustion. The models developed can be applied toward reactor design and optimization in the context of enhanced olefin production via SHC under a cyclic redox scheme. DA - 2019/// PY - 2019/// DO - 10.1002/ente.201900738 VL - 8 IS - 8 SP - 1900738 KW - combustion KW - cracking KW - dehydrogenation KW - kinetics KW - olefin KW - perovskites KW - reduction ER - TY - JOUR TI - A- and B-site Codoped SrFeO3 Oxygen Sorbents for Enhanced Chemical Looping Air Separation AU - Dou, Jian AU - Krzystowczyk, Emily AU - Wang, Xijun AU - Robbins, Thomas AU - Ma, Liang AU - Liu, Xingbo AU - Li, Fanxing T2 - CHEMSUSCHEM AB - Chemical-looping air separation has numerous potential benefits in terms of energy saving and emission reductions. The current study details a combination of density functional theory calculation and experimental efforts to design A- and B-site codoped SrFeO3 perovskites as "low-temperature" oxygen sorbents for chemical-looping air separation. Substitution of the SrFeO3 host structure with Ca and Co lowers oxygen vacancy formation energy by 0.24-0.46 eV and decreases the oxygen release temperature. As a result, Sr1-x Cax Fe1-y Coy O3 (SCFC; x=0.2, 0.040 min) without signs of coke formation. When used as supports for NiO, the resulting oxygen carriers showed no sign of carbon deposition under typical methane CLC environments. In comparison, NiO supported on inert MgAl2O4 exhibited significant coke formation after only 2.5 min. Moreover, NiO supported on NiFe2O4 and BaFe2O4 exhibited faster redox activity and higher oxygen carrying capacity when compared to the inert MgAl2O4-supported NiO. Detailed investigation of the reduction behavior of NiFe2O4-supported NiO revealed extensive solid-state reactions and Ni/Fe exchanges among the support, NiO, and newly formed phases. Specifically, initial weight loss in NiFe2O4-supported NiO was associated with reduction of the oxygen carrier to metallic Ni and Fe3O4 phases. Subsequent coke inhibition was attributed to the slow reduction of Fe3O4 and FeO phases. Multi-cyclic redox studies indicated that NiFe2O4-supported NiO gradually lost its redox activity. In comparison, both MgFe2O4- and BaFe2O4-supported NiO exhibited satisfactory redox stability, activity, and coke resistance. DA - 2019/// PY - 2019/// DO - 10.1016/j.cattod.2019.09.010 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85072723300&partnerID=MN8TOARS ER - TY - JOUR TI - BiVO4 nanocrystals with controllable oxygen vacancies induced by Zn-doping coupled with graphene quantum dots for enhanced photoelectrochemical water splitting AU - Pan, Qingguang AU - Yang, Kunran AU - Wang, Guoliang AU - Li, Dongdong AU - Sun, Jing AU - Yang, Bo AU - Zou, Zhiqing AU - Hu, Weibo AU - Wen, Ke AU - Yang, Hui T2 - Chemical Engineering Journal AB - The weak electron-hole pair separation and transfer of the BiVO4 photoanode restrain its photoelectrochemical performance of water splitting. In this work, we focus on Zn doping to replace Bi-sites within BiVO4 nanocrystals to promote efficient charge separation and transfer. Theoretical and experimental results show that Zn doping induces oxygen vacancies with controllable content. Zn doping and oxygen vacancies not only shift the conduction and valance band positions of BiVO4, resulting a local built-in electric field, but also increase the carrier density, which would be beneficial for charge separation and transfer. In the meantime, water adsorption on Bi-sites is also activated, which would help water splitting. As a result, these contributions synergistically enhance photoelectrochemical performance with the incident photon-to-current conversion efficiency (IPCE) of 34% at 0.6 V vs. RHE, which is much higher than that of pristine BiVO4. Furthermore, by sequentially electrodepositing graphene quantum dots (GQDs) and cobalt phosphate (Co-Pi) nano-film, we have constructed a hybrid Zn-BiVO4/GQDs/Co-Pi structure to broaden the light absorption and to enhance the stability, its IPCE reaches as high as 57% and photocurrent density achieves 3.01 mA cm−2 at 0.6 V vs. RHE, which is 8.6 times of the pristine BiVO4, thus providing an efficient strategy for the structure design of BiVO4 based photoelectrodes. DA - 2019/9// PY - 2019/9// DO - 10.1016/j.cej.2019.04.161 VL - 372 SP - 399-407 UR - https://doi.org/10.1016/j.cej.2019.04.161 KW - Zn dopant KW - BiVO4 KW - Oxygen vacancies KW - GQDs KW - Water splitting ER - TY - JOUR TI - CRATES: A one-step assembly method for Class 2 CRISPR arrays AU - Liao, Chunyu AU - Slotkowski, Rebecca A. AU - Beisel, Chase L. T2 - TUMOR IMMUNOLOGY AND IMMUNOTHERAPY - MOLECULAR METHODS AB - CRISPR-Cas systems naturally rely on CRISPR arrays to achieve immunity against multiple foreign invaders, where these arrays are also being utilized for multiplexed targeting as part of CRISPR technologies. However, CRISPR arrays have proven difficult to synthesize or assemble to-date due to the repetitive DNA repeats in each array. To overcome this barrier, we recently reported a cloning method we term CRATES (CRISPR Assembly through Trimmed Ends of Spacers) for the single-step, efficient generation of large Class 2 CRISPR arrays. CRATES generates CRISPR arrays through assembly of multiple repeat-spacer subunits using defined junction sequences within the trimmed portion of the CRISPR spacers. These arrays can be utilized by single-effector nucleases associated with Class 2 CRISPR-Cas systems, such as Cas9, Cas12a/Cpf1, or Cas13a/C2c2. Here, we describe in detail the steps for generating arrays utilized by Cas9 and Cas12a as well as composite arrays co-utilized by both nucleases. We also generate a representative three-spacer array and demonstrate multiplexed DNA cleavage through plasmid-clearance assays in Escherichia coli. This method is expected to simplify the study of natural CRISPR arrays and facilitate multiplexed targeting with programmable nucleases from Class 2 Cas nucleases across the myriad applications of CRISPR technologies. DA - 2019/// PY - 2019/// DO - 10.1016/bs.mie.2019.04.011 VL - 629 SP - 493-511 SN - 0076-6879 ER - TY - JOUR TI - Terahertz Waveguide Signal Processing: Passive and Active Devices AU - Reichel, Kimberly S. AU - Lozada-Smith, Nicolas AU - Joshipura, Ishan D. AU - Ma, Jianjan AU - Shrestha, Rabi AU - Mendis, Rajind AU - Dickey, Michael D. AU - Mittleman, Daniel M. T2 - TERAHERTZ EMITTERS, RECEIVERS, AND APPLICATIONS X AB - Based on parallel-plate waveguides (PWWGs), we have developed both passive and active terahertz (THz) sensors, filters, splitters, and switches. We utilize the PPWG since it has excellent waveguiding properties with a simple geometry that allows for incorporation of unique electromagnetic functionalities. A few passive devices are discussed while the focus remains on active devices. The active control is enabled by our innovation to incorporate liquid metals, which can be relocated by application of a small electrical voltage (< 4V), as part of the waveguide geometry itself. The device geometry directly affects the device performance (e.g., frequency band of operation, channel output power). Therefore, by moving the liquid metal, the geometry is reconfigured which results in altering the device function. To show the practicality of these devices to be used for THz wireless communications, we demonstrate the ability of these devices to support a 1 Gb/s data stream on a THz carrier wave and show that this signal can be successfully switched with high modulation depths of ±40 dB. These results show the strong promise of these components to form important signal processing building blocks in the future infrastructure of THz wireless communications. DA - 2019/// PY - 2019/// DO - 10.1117/12.2527413 VL - 11124 SP - SN - 1996-756X KW - terahertz KW - waveguides KW - liquid metals KW - signal processing ER - TY - JOUR TI - Functionalized Textiles: Water-Stable Chemical-Protective Textiles via Euhedral Surface-Oriented 2D Cu-TCPP Metal-Organic Frameworks (Small 10/2019) AU - Lee, Dennis T. AU - Jamir, Jovenal D. AU - Peterson, Gregory W. AU - Parsons, Gregory N. T2 - Small AB - In article number 1805133, Gregory N. Parsons and co-workers effectively separate highly toxic chemicals including NH3 and 2-chloroethyl ethyl sulfide (CEES), a vesicant sulfur mustard simulant, through non-woven textiles functionalized with 2-D metal–organic frameworks (MOFs). The chemical protective membranes can potentially be applied to gas mask filters and to military garments to protect military populations from such hazards. DA - 2019/3// PY - 2019/3// DO - 10.1002/SMLL.201970054 VL - 15 IS - 10 SP - 1970054 J2 - Small LA - en OP - SN - 1613-6810 UR - http://dx.doi.org/10.1002/SMLL.201970054 DB - Crossref ER - TY - JOUR TI - Modular‐scale ethane to liquids via chemical looping oxidative dehydrogenation: Redox catalyst performance and process analysis AU - Neal, Luke AU - Haribal, Vasudev AU - McCaig, Joseph AU - Lamb, H. Henry AU - Li, Fanxing T2 - Journal of Advanced Manufacturing and Processing AB - Abstract The difficulties in the liquefaction and transportation of ethane in shale gas has led to significant rejection, via reinjection or flaring, of this valuable hydrocarbon resource. Upgrading this low‐value, isolated ethane into easily transportable liquid fuels is a promising solution to this supply glut. In this study, we present a modular system that can potentially be operated economically at geographically isolated gas‐processing facilities. The modular ethane‐to‐liquids (M‐ETL) system uses a chemical looping‐oxidative dehydrogenation (CL‐ODH) technology to efficiently convert ethane and natural gas liquids into olefins (primarily ethylene) via cyclic redox reactions of highly effective redox catalyst particles. The resulting olefins are then converted to gasoline and mid‐distillate products via oligomerization. CL‐ODH eliminates air separation and equilibrium limitations for olefin generation. It also simplifies the process scheme and reduces energy consumption. Here, we present experimental proof‐of‐concept data on CL‐ODH conversion of ethane to ethylene. Using the CL‐ODH performance data at 750°C, we show that a simple, single‐pass configuration can be economically viable at distributed sites. We identify that economic factors such as the capital cost, price of ethane feed, and value of electricity byproduct have strong effects on the required selling price of the liquids. It is also noted that the economic viability of the M‐ETL system is relatively insensitive to the liquid yield under a low ethane price scenario. The demand and value of electricity at distributed locations, on the other hand, can play an important role in the optimal process configuration and economics. DA - 2019/4// PY - 2019/4// DO - 10.1002/AMP2.10015 VL - 1 IS - 1-2 SP - e10015 J2 - J Adv Manuf Process LA - en OP - SN - 2637-403X 2637-403X UR - http://dx.doi.org/10.1002/AMP2.10015 DB - Crossref ER - TY - JOUR TI - Peter Cummings - a pillar in the field of statistical mechanics and molecular simulation FOREWORD AU - Hall, Carol K. AU - Kofke, David A. AU - Galindo, Amparo AU - Gil-Villegas, Alejandro AU - Striolo, Alberto AU - Jackson, George T2 - MOLECULAR PHYSICS DA - 2019/// PY - 2019/// DO - 10.1080/00268976.2019.1684664 VL - 117 IS - 23-24 SP - 3479-3483 SN - 1362-3028 ER - TY - JOUR TI - Rationally designed carbohydrate-occluded epitopes elicit HIV-1 Env-specific antibodies AU - Zhu, Cheng AU - Dukhovlinova, Elena AU - Council, Olivia AU - Ping, Lihua AU - Faison, Edgar M. AU - Prabhu, Shamit S. AU - Potter, E. Lake AU - Upton, Stephen L. AU - Yin, Guowei AU - Fay, James M. AU - Kincer, Laura P. AU - Spielvogel, Ean AU - Campbell, Sharon L. AU - Benhabbour, S. Rahima AU - Ke, Hengming AU - Swanstrom, Ronald AU - Dokholyan, Nikolay V. T2 - NATURE COMMUNICATIONS AB - An array of carbohydrates masks the HIV-1 surface protein Env, contributing to the evasion of humoral immunity. In most HIV-1 isolates 'glycan holes' occur due to natural sequence variation, potentially revealing the underlying protein surface to the immune system. Here we computationally design epitopes that mimic such surface features (carbohydrate-occluded neutralization epitopes or CONE) of Env through 'epitope transplantation', in which the target region is presented on a carrier protein scaffold with preserved structural properties. Scaffolds displaying the four CONEs are examined for structure and immunogenicity. Crystal structures of two designed proteins reflect the computational models and accurately mimic the native conformations of CONEs. The sera from rabbits immunized with several CONE immunogens display Env binding activity. Our method determines essential structural elements for targets of protective antibodies. The ability to design immunogens with high mimicry to viral proteins also makes possible the exploration of new templates for vaccine development. DA - 2019/2/27/ PY - 2019/2/27/ DO - 10.1038/s41467-019-08876-w VL - 10 SP - SN - 2041-1723 ER - TY - JOUR TI - Computational Study of Thermosensitivity of Liposomes Modulated by Leucine Zipper-Structured Lipopeptides AU - Xiejun, Xu AU - Xingqing, Xiao AU - Shouhong, Xu AU - Hongai, Liu T2 - ACTA PHYSICO-CHIMICA SINICA DA - 2019/// PY - 2019/// DO - 10.3866/PKU.WHXB201806034 VL - 35 IS - 6 SP - 598-606 SN - 1000-6818 KW - Leucine zipper-structured lipopeptides KW - Thermosensitive liposomes KW - Cancer therapy KW - Drug carrier KW - Molecular dynamics simulation ER - TY - JOUR TI - Rapid Open-Air Digital Light 3D Printing of Thermoplastic Polymer AU - Deng, Shihong AU - Wu, Jingjun AU - Dickey, Michael D. AU - Zhao, Qian AU - Xie, Tao T2 - ADVANCED MATERIALS AB - 3D printing has witnessed a new era in which highly complexed customized products become reality. Realizing its ultimate potential requires simultaneous attainment of both printing speed and product versatility. Among various printing techniques, digital light processing (DLP) stands out in its high speed but is limited to intractable light curable thermosets. Thermoplastic polymers, despite their reprocessibility that allows more options for further manipulation, are restricted to intrinsically slow printing methods such as fused deposition modeling. Extending DLP to thermoplastics is highly desirable, but is challenging due to the need to reach rapid liquid-solid separation during the printing process. Here, a successful attempt at DLP printing of thermoplastic polymers is reported, realized by controlling two competing kinetic processes (polymerization and polymer dissolution) simultaneously occurring during printing. With a selected monomer, 4-acryloylmorpholine (ACMO), printing of thermoplastic 3D scaffolds is demonstrated, which can be further converted into various materials/devices utilizing its unique water-soluble characteristic. The ultralow viscosity of ACMO, along with surface oxygen inhibition, allows rapid liquid flow toward high-speed open-air printing. The process simplicity, enabling mechanism, and material versatility broaden the scope of 3D printing in constructing functional 3D devices including reconfigurable antenna, shape-shifting structures, and microfluidics. DA - 2019/9// PY - 2019/9// DO - 10.1002/adma.201903970 VL - 31 IS - 39 SP - SN - 1521-4095 KW - 3D printing KW - DLP printing KW - microfluidics KW - shape-memory polymers KW - thermoplastic polymers ER - TY - JOUR TI - DERIVATION OF HUMAN TROPHOBLAST STEM CELLS FROM HUMAN PLURIPOTENT STEM CELLS AU - Mischler, Adam AU - Karakis, Victoria AU - San Miguel, Adriana AU - Rao, Balaji T2 - PLACENTA AB - Conventional soil maps contain valuable knowledge on soil–environment relationships. Such knowledge can be extracted for use when updating conventional soil maps with improved environmental data. Existing methods take all polygons of the same map unit on a map as a whole to extract the soil–environment relationship. Such approach ignores the difference in the environmental conditions represented by individual soil polygons of the same map unit. This paper proposes a method of mining soil–environment relationships from individual soil polygons to update conventional soil maps. The proposed method consists of three major steps. Firstly, the soil–environment relationships represented by each individual polygon on a conventional soil map are extracted in the form of frequency distribution curves for the involved environmental covariates. Secondly, for each environmental covariate, these frequency distribution curves from individual polygons of the same soil map unit are synthesized to form the overall soil–environment relationship for that soil map unit across the mapped area. And lastly, the extracted soil–environment relationships are applied to updating the conventional soil map with new, improved environmental data by adopting a soil land inference model (SoLIM) framework. This study applied the proposed method to updating a conventional soil map of the Raffelson watershed in La Crosse County, Wisconsin, United States. The result from the proposed method was compared with that from the previous method of taking all polygons within the same soil map unit on a map as a whole. Evaluation results with independent soil samples showed that the proposed method exhibited better performance and produced higher accuracy. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.placenta.2019.06.193 VL - 83 SP - E59-E59 SN - 1532-3102 ER - TY - JOUR TI - Navigating Complexity Using Systems Thinking in Chemistry, with Implications for Chemistry Education AU - Constable, David J. C. AU - Jimenez-Gonzalez, Concepcion AU - Matlin, Stephen A. T2 - JOURNAL OF CHEMICAL EDUCATION AB - To remain relevant, chemists need to be able to understand their work in terms of systems. Since systems thinking is a framework to understand and manage systems, the introduction of systems thinking in chemistry education would assist learners to navigate complex, inter-related concepts typical of systems. At the same time, the adoption of systems thinking in chemistry education will require a major reorientation in how chemistry is taught. We consider several characteristics of system complexity that are key to systems thinking in chemistry–including purpose, scale, boundaries, hierarchies, constraints, loop concepts and emergence–and discuss their introduction in education and the benefits this will bring. DA - 2019/12// PY - 2019/12// DO - 10.1021/acs.jchemed.9b00368 VL - 96 IS - 12 SP - 2689-2699 SN - 1938-1328 KW - High School/Introductory Chemistry KW - First-Year Undergraduate/General KW - Second-Year Undergraduate KW - Curriculum KW - Environmental Chemistry KW - Interdisciplinary/Multidisciplinary: Problem Solving/Decision Making KW - Systems Thinking KW - Applications of Chemistry KW - Green Chemistry ER - TY - JOUR TI - Smartphone‐based clinical diagnostics: towards democratization of evidence‐based health care AU - Hernández‐Neuta, I. AU - Neumann, F. AU - Brightmeyer, J. AU - Tis, T. Ba AU - Madaboosi, N. AU - Wei, Q. AU - Ozcan, A. AU - Nilsson, M. T2 - Journal of Internal Medicine AB - Abstract Recent advancements in bioanalytical techniques have led to the development of novel and robust diagnostic approaches that hold promise for providing optimal patient treatment, guiding prevention programs and widening the scope of personalized medicine. However, these advanced diagnostic techniques are still complex, expensive and limited to centralized healthcare facilities or research laboratories. This significantly hinders the use of evidence‐based diagnostics for resource‐limited settings and the primary care, thus creating a gap between healthcare providers and patients, leaving these populations without access to precision and quality medicine. Smartphone‐based imaging and sensing platforms are emerging as promising alternatives for bridging this gap and decentralizing diagnostic tests offering practical features such as portability, cost‐effectiveness and connectivity. Moreover, towards simplifying and automating bioanalytical techniques, biosensors and lab‐on‐a‐chip technologies have become essential to interface and integrate these assays, bringing together the high precision and sensitivity of diagnostic techniques with the connectivity and computational power of smartphones. Here, we provide an overview of the emerging field of clinical smartphone diagnostics and its contributing technologies, as well as their wide range of areas of application, which span from haematology to digital pathology and rapid infectious disease diagnostics. DA - 2019/1// PY - 2019/1// DO - 10.1111/joim.12820 VL - 285 IS - 1 SP - 19-39 UR - https://doi.org/10.1111/joim.12820 KW - Biosensors KW - Diagnostics KW - Digital pathology KW - Lab-on-a-chip KW - Smartphones ER - TY - JOUR TI - Non-invasive plant disease diagnostics enabled by smartphone-based fingerprinting of leaf volatiles AU - Li, Zheng AU - Paul, Rajesh AU - Tis, Taleb Ba AU - Saville, Amanda C. AU - Hansel, Jeana C. AU - Yu, Tao AU - Ristaino, Jean B. AU - Wei, Qingshan T2 - Nature Plants DA - 2019/7/29/ PY - 2019/7/29/ DO - 10.1038/s41477-019-0476-y UR - https://doi.org/10.1038/s41477-019-0476-y ER - TY - JOUR TI - Hydrogel/Elastomer Laminates Bonded via Fabric Interphases for Stimuli-Responsive Actuators AU - Hubbard, Amber M. AU - Cui, Wei AU - Huang, Yiwan AU - Takahashi, Riku AU - Dickey, Michael D. AU - Genzer, Jan AU - King, Daniel R. AU - Gong, Jian Ping T2 - MATTER AB - The human body is composed of composite structures made of water-rich hydrophilic domains and hydrophobic barriers. Combining hydrogels with elastomers results in similar synthetic biomaterials applicable to fields ranging from stretchable electronics to actuators. Here, we report a method to combine hydrogels with elastomers via a glass fiber fabric interphase. The interphase plays two roles: it enables chemically different materials to be robustly bound without chemical treatment while also dramatically improving the mechanical properties of the composite. Maximum interfacial adhesion energies of ∼1,000 N m−1 between the hydrogel and fabric and ∼360 N m−1 between the elastomer and fabric approach adhesion values of chemically bound soft materials. The composite tearing toughness (143 kJ m−2) vastly exceeds that of all neat components. In these materials, Young's modulus is high (∼1.2 GPa), while bending modulus is low (∼7 MPa), resulting in structures that can serve as actuators through controlled solvent exposure. DA - 2019/9/4/ PY - 2019/9/4/ DO - 10.1016/j.matt.2019.04.008 VL - 1 IS - 3 SP - 674-689 SN - 2590-2385 ER - TY - JOUR TI - An educational module to explore CRISPR technologies with a cell-free transcription-translation system AU - Collias, Daphne AU - Marshall, Ryan AU - Collins, Scott P. AU - Beisel, Chase L. AU - Noireaux, Vincent T2 - SYNTHETIC BIOLOGY AB - Within the last 6 years, CRISPR-Cas systems have transitioned from adaptive defense systems in bacteria and archaea to revolutionary genome-editing tools. The resulting CRISPR technologies have driven innovations for treating genetic diseases and eradicating human pests while raising societal questions about gene editing in human germline cells as well as crop plants. Bringing CRISPR into the classroom therefore offers a means to expose students to cutting edge technologies and to promote discussions about ethical questions at the intersection of science and society. However, working with these technologies in a classroom setting has been difficult because typical experiments rely on cellular systems such as bacteria or mammalian cells. We recently reported the use of an E. coli cell-free transcription-translation (TXTL) system that simplifies the demonstration and testing of CRISPR technologies with shorter experiments and limited equipment. Here, we describe three educational modules intended to expose undergraduate students to CRISPR technologies using TXTL. The three sequential modules comprise (i) designing the RNAs that guide DNA targeting, (ii) measuring DNA cleavage activity in TXTL and (iii) testing how mutations to the targeting sequence or RNA backbone impact DNA binding and cleavage. The modules include detailed protocols, questions for group discussions or individual evaluation, and lecture slides to introduce CRISPR and TXTL. We expect these modules to allow students to experience the power and promise of CRISPR technologies in the classroom and to engage with their instructor and peers about the opportunities and potential risks for society. DA - 2019/// PY - 2019/// DO - 10.1093/synbio/ysz005 VL - 4 IS - 1 SP - SN - 2397-7000 KW - CRISPR KW - Cas9 KW - education modules KW - synthetic biology KW - TXTL ER - TY - JOUR TI - Simulating Emergent Spatiotemporal Actomyosin Dynamics to Understand Spatial Regulation of Non-Muscle Myosin II AU - Miller, Callie J. AU - LaFosse, Paul AU - Asokan, Sreeja AU - Haugh, Jason AU - Bear, James E. AU - Elston, Timothy C. T2 - Biophysical Journal AB - The punctuated dynamics of cortical actomyosin are critical for cell migration in applications like cancer, wound healing, or morphogenesis, however the mechanical role and organization of cortical actomyosin is not well understood. We developed a Monte Carlo, particle-based computer simulation that resulted in emergent actomyosin asters. In particular, we were interested to understand the role of non-muscle myosin II's (motor) activation in emergent f-actin (filament) aster formation. Our model incorporates activation of individual motors through the transition from an inactive folded state to an active unfolded state, and the bundling of two active motors to form a processive motor capable of binding to filaments. In addition to considering how changing a single parameter affected the emergent filament asters, we introduced a spatial gradient of model parameters to mimic spatially controlled activation of motors, or filament polymerization. Recent studies have shown that regulation of motor activity is critical for directed fibroblast migration in response to a gradient of platelet derived growth factor, and we found that spatially inhibiting motor-filament binding resulted in spatial variations in filament aster formation. Additionally, motivated from studies with the small molecule ROCK inhibitor, Y-27632, and Calyculin A, which either disrupt or enhance the ability of non-muscle myosin II to exert force, and work from the Sellers lab on the biochemical properties of different types of co-assembled myosin isoforms, we simulated spatially controlled motor stiffness which directly affects the ability of motors to exert force to reorganize filaments. We found that not only was there a change in where asters emerged, but that we were able to generate a dynamic pulsatile aster structure where filament asters would dissipate and new asters would emerge. Results from our simulation will guide future experimentation for cortical actomyosin. DA - 2019/2// PY - 2019/2// DO - 10.1016/J.BPJ.2018.11.1372 VL - 116 IS - 3 SP - 251a J2 - Biophysical Journal LA - en OP - SN - 0006-3495 UR - http://dx.doi.org/10.1016/J.BPJ.2018.11.1372 DB - Crossref ER - TY - JOUR TI - EFFECTS OF FORMIC AND LEVULINIC ACIDS ON BUTYRIC ACID SYNTHESIS BY CLOSTRIDIUM TYROBUTYRICUM IN XYLOSE MEDIA AU - Liu, Y. AU - Geng, Y. AU - Zhao, R. AU - Zheng, H. AU - Yuan, W. T2 - TRANSACTIONS OF THE ASABE AB - Abstract. Weak acids released during hydrolysis of lignocellulosic biomass are potential inhibitors of microorganism fermentation. In this study, the effects of formic and levulinic acids on butyric acid synthesis by were investigated. With the addition of 1.2 to 4.8 g L -1 of formic acid, increased lag time, decreased cell density, and lower butyric acid productivity were observed. Up to 15% and 56% reduction in peak cell density and butyric acid productivity, respectively, were caused by formic acid addition, whereas there was no significant difference in butyric acid yield between the control and formic acid treated groups (except for the 2.4 g formic acid L -1 treatment). Levulinic acid did not show any notable effects on within the investigated concentration range (0 to 4.8 g L -1 ). Overall, showed strong tolerance of both formic and levulinic acids, but neither of these acids could be metabolized by the microbe. Highlights Formic acid had dosage-dependent inhibitory effects on C. tyrobutyricum. Levulinic acid had no effects on cell growth or butyrate synthesis. Neither formic acid nor levulinic acid was metabolized by C. tyrobutyricum. C. tyrobutyricum showed strong tolerance to formic acid and levulinic acid. Keywords: Butyric acid, Clostridium tyrobutyricum, Formic acid, Levulinic acid, Lignocellulosic hydrolysate, Xylose. DA - 2019/// PY - 2019/// DO - 10.13031/trans.13669 VL - 62 IS - 6 SP - 1803-1809 SN - 2151-0040 KW - Butyric acid KW - Clostridium tyrobutyricum KW - Formic acid KW - Levulinic acid KW - Lignocellulosic hydrolysate KW - Xylose ER - TY - JOUR TI - Bottom-Up Approach to the Coarse-Grained Surface Model: Effective Solid–Fluid Potentials for Adsorption on Heterogeneous Surfaces AU - Shi, Kaihang AU - Santiso, Erik E. AU - Gubbins, Keith E. T2 - Langmuir AB - Coarse-grained surface models with a low-dimension positional dependence have great advantages in simplifying the theoretical adsorption model and speeding up molecular simulations. In this work, we present a bottom-up strategy, developing a new two-dimensional (2D) coarse-grained surface model from the "bottom-level" atomistic model, for adsorption on highly heterogeneous surfaces with various types of defects. The corresponding effective solid-fluid potential consists of a 2D hard wall potential representing the structure of the surface and a one-dimensional (1D) effective area-weighted free-energy-averaged (AW-FEA) potential representing the energetic strength of the substrate-adsorbate interaction. Within the conventional free-energy-averaged (FEA) framework, an accessible-area-related parameter is introduced into the equation of the 1D effective solid-fluid potential, which allows us not only to obtain the energy information from the fully atomistic system but also to get the structural dependence of the potential on any geometric defect on the surface. Grand canonical Monte Carlo simulations are carried out for argon adsorption at 87.3 K to test the validity of the new 2D surface model against the fully atomistic system. We test four graphitic substrates with different levels of geometric roughness for the top layer, including the widely used reference solid substrate Cabot BP-280. The simulation results show that adding one more dimension to the traditional 1D surface model is essential for adsorption on the geometrically heterogeneous surfaces. In particular, the 2D surface model with the AW-FEA solid-fluid potential significantly improves the adsorption isotherm and density profile over the 1D surface model with the FEA solid-fluid potential over a wide range of pressure. The method to construct an effective solid-fluid potential for an energetically heterogeneous surface is also discussed. DA - 2019/4/8/ PY - 2019/4/8/ DO - 10.1021/ACS.LANGMUIR.9B00440 VL - 35 IS - 17 SP - 5975-5986 J2 - Langmuir LA - en OP - SN - 0743-7463 1520-5827 UR - http://dx.doi.org/10.1021/ACS.LANGMUIR.9B00440 DB - Crossref ER - TY - JOUR TI - Magnetic Actuators: 3D‐Printed Silicone Soft Architectures with Programmed Magneto‐Capillary Reconfiguration (Adv. Mater. Technol. 4/2019) AU - Roh, Sangchul AU - Okello, Lilian B. AU - Golbasi, Nuran AU - Hankwitz, Jameson P. AU - Liu, Jessica A.‐C. AU - Tracy, Joseph B. AU - Velev, Orlin D. T2 - Advanced Materials Technologies AB - In article number 1800528, Sangchul Roh, Orlin D. Velev, and co-workers present a new class of 3D-printed soft mesh actuators floating on water. They exhibit reversible and programmable shape reconfiguration via combined magnetic and capillary forces. The silicone meshes can carry single droplets of water and dispense them on demand. DA - 2019/4// PY - 2019/4// DO - 10.1002/ADMT.201970021 VL - 4 IS - 4 SP - 1970021 J2 - Adv. Mater. Technol. LA - en OP - SN - 2365-709X 2365-709X UR - http://dx.doi.org/10.1002/ADMT.201970021 DB - Crossref ER - TY - JOUR TI - Phase Separation in Liquid Metal Nanoparticles AU - Tang, Shi-Yang AU - Mitchell, David R.G. AU - Zhao, Qianbin AU - Yuan, Dan AU - Yun, Guolin AU - Zhang, Yuxin AU - Qiao, Ruirui AU - Lin, Yiliang AU - Dickey, Michael D. AU - Li, Weihua T2 - Matter AB - Nanoparticles produced from gallium-based liquid metal alloys have been explored for developing applications in the fields of electronics, catalysis, and biomedicine. Nonetheless, physical properties, such as phase behavior at micro-/nanosize scale, are still significantly underexplored for such nanoparticles. Here, we conduct an in situ investigation of phase behavior for gallium-based liquid metal nanoparticles and discover the unprecedented coexistence of solid particles in spherical liquid metal shells without the support of a crystalline substrate. The particles can also transform into solid Janus nanoparticles after temperature cycling. In addition, we investigate the optical properties of the nanoparticles before and after phase separation using in situ electron energy-loss spectroscopy. Most importantly, we discover that increasing the content of indium within the nanoparticle can stabilize the solid-core/liquid-shell structure at room temperature. This study provides a foundation to engineer liquid metal nanoparticles for developing new applications in nanoscale optical platforms and shape-configurable transformers. DA - 2019/7// PY - 2019/7// DO - 10.1016/J.MATT.2019.03.001 VL - 1 IS - 1 SP - 192-204 J2 - Matter LA - en OP - SN - 2590-2385 UR - http://dx.doi.org/10.1016/J.MATT.2019.03.001 DB - Crossref ER - TY - JOUR TI - Discovery and Evaluation of Peptide Ligands for Selective Adsorption and Release of Cas9 Nuclease on Solid Substrates AU - Day, Kevin AU - Prodromou, Raphael AU - Bosari, Sahand Saberi AU - Lavoie, Ashton AU - Omary, Mohammad AU - Market, Connor AU - San Miguel, Adriana AU - Menegatti, Stefano T2 - BIOCONJUGATE CHEMISTRY AB - The rapid expansion of CRISPR in biotechnology, medicine, and bioprocessing poses an urgent need for advanced manufacturing of Cas nucleases. The lack of Cas-targeting ligands, however, prevents the development of platform processes for purifying this class of molecules. This work represents the first effort at developing short synthetic Cas9-binding peptides and demonstrates their applicability as affinity ligands for the purification of a Cas nuclease. Candidate Cas9-targeting peptides were initially identified by screening a solid-phase peptide library against a model mixture of Streptococcus pyogenes Cas9 spiked in Escherichia coli cell lysate. An ensemble of homologous sequences was identified, conjugated on Toyopearl resin, and evaluated by Cas9 binding studies to identify sequences providing selective Cas9 capture and efficient release. In silico docking studies were also performed to evaluate the binding energy and site of the various peptides on Cas9. Notably, sequences GYYRYSEY and YYHRHGLQ were shown to target the RecII domain of Cas9, which is not involved in nuclease activity and was targeted as an ideal binding site. The peptide ligands were validated by purifying Cas9 from the E. coli lysate in dynamic conditions and through measurements of binding capacity and strength (Qmax and KD). The resulting values of Qmax = 4–5 mg Cas9 per mL of resin and KD ∼ 0.1–0.3 μM, product recovery (86–89%), and purity (91%–93%) indicate that both peptides, and YYHRHGLQ in particular, can serve as capture ligands in a platform purification process of Cas9. DA - 2019/12// PY - 2019/12// DO - 10.1021/acs.bioconjchem.9b00703 VL - 30 IS - 12 SP - 3057-3068 SN - 1520-4812 UR - http://dx.doi.org/10.1021/acs.bioconjchem.9b00703 ER - TY - JOUR TI - Washable, durable and flame retardant conductive textiles based on reduced graphene oxide modification AU - Zhao, Yintao AU - Wang, Jin AU - Li, Zengqing AU - Zhang, Xiangwu AU - Tian, Mingwei AU - Zhang, Xiansheng AU - Liu, Xuqing AU - Qu, Lijun AU - Zhu, Shifeng T2 - CELLULOSE AB - Graphene has been highlighted in a variety of wearable electronics and smart textiles applications due to its unique properties such as high conductivity, transparency, flexibility and other excellent mechanical performance. Although there have been extensive efforts for graphene based conductive fibers/yarns, there are remaining challenges in terms of the seamless integration between 2D flakes, and reduced charge transport in a lower carrier concentration. Unstable resistance probably arises from the creation of gaps in the conductive parts of the smart textile. Also, regional temperatures can get too high, constituting a fire-safety hazard and endangering the wearer's safety. In this work, the synergistic effect of graphene and flame-retardant materials was investigated, and a conductive fabric was developed which is highly conductive and flame retardancy. Graphene has excellent electrical and thermal conductivity and acts synergistically with traditional flame-retardants on common fabrics. The electrical surface resistivity of hybrid material modified fabrics was as low as 0.54 kΩ/sq, so they could serve as safe and highly conductive conductor in a simple circuit and show excellent wash-ability. The limiting oxygen index of the fabric increased from 19 to 32 after modification in conjunction with the residue at 800 °C increased from 17.9 to 31%, which could be used as safe and highly conductive materials for smart textiles and wearable devices. DA - 2019/// PY - 2019/// DO - 10.1007/s10570-019-02884-1 KW - Polyester KW - cotton fabric KW - Graphene oxide KW - Phosphate flame retardant KW - Electrical surface resistivity KW - Flame retardancy ER - TY - JOUR TI - Generating Surface-Anchored Zwitterionic Networks and Studying Their Resistance to Bovine Serum Albumin Adsorption AU - Walker, Edwin J., Jr. AU - Pandiyarajan, C. K. AU - Efimenko, Kirill AU - Genzer, Jan T2 - ACS APPLIED POLYMER MATERIALS AB - We report a simple method to generate surface-anchored zwitterionic network coatings that exhibit low nonspecific protein adsorption. We first synthesize amphiphilic random copolymers comprising 2-(dimethylamino)ethyl methacrylate (DMAEMA) and propargyl methacrylate (PGMA) units in two different nominal molar ratios (50:50 and 75:25) by free radical copolymerization. The DMAEMA moieties in the copolymers are then betainized with 1,3-propane sultone to obtain zwitterionic macromolecules. We create substrate-anchored network coatings by casting thin copolymer films (∼100 nm) containing 2 wt % of photoactive benzophenone onto a polystyrene substrate and cross-link them by UV-light irradiation at 365 nm (UV dose = 9–10 J/cm2). We investigate the cross-linking reaction with infrared spectroscopy, monitor the change in film thickness, and study the swelling behavior of the coatings as a function of ionic strength and electrolyte using spectroscopic ellipsometry. We demonstrate the performance of such surface-attached zwitterionic networks by studying their resistance to nonspecific adsorption of bovine serum albumin (BSA). DA - 2019/12// PY - 2019/12// DO - 10.1021/acsapm.9b00772 VL - 1 IS - 12 SP - 3323-3333 SN - 2637-6105 KW - zwitterion KW - antifouling coatings KW - BSA adsorption KW - surface-attached networks KW - gel swelling ER - TY - JOUR TI - Targeted transcriptional modulation with type I CRISPR-Cas systems in human cells AU - Pickar-Oliver, Adrian AU - Black, Joshua B. AU - Lewis, Mae M. AU - Mutchnick, Kevin J. AU - Klann, Tyler S. AU - Gilcrest, Kylie A. AU - Sitton, Madeleine J. AU - Nelson, Christopher E. AU - Barrera, Alejandro AU - Bartelt, Luke C. AU - Reddy, Timothy E. AU - Beisel, Chase L. AU - Barrangou, Rodolphe AU - Gersbach, Charles A. T2 - NATURE BIOTECHNOLOGY AB - Class 2 CRISPR–Cas systems, such as Cas9 and Cas12, have been widely used to target DNA sequences in eukaryotic genomes. However, class 1 CRISPR–Cas systems, which represent about 90% of all CRISPR systems in nature, remain largely unexplored for genome engineering applications. Here, we show that class 1 CRISPR–Cas systems can be expressed in mammalian cells and used for DNA targeting and transcriptional control. We repurpose type I variants of class 1 CRISPR–Cas systems from Escherichia coli and Listeria monocytogenes, which target DNA via a multi-component RNA-guided complex termed Cascade. We validate Cascade expression, complex formation and nuclear localization in human cells, and demonstrate programmable CRISPR RNA (crRNA)-mediated targeting of specific loci in the human genome. By tethering activation and repression domains to Cascade, we modulate the expression of targeted endogenous genes in human cells. This study demonstrates the use of Cascade as a CRISPR-based technology for targeted eukaryotic gene regulation, highlighting class 1 CRISPR–Cas systems for further exploration. Type I CRISPR–Cas systems, the largest group of CRISPR systems in nature, can be repurposed for DNA targeting and gene regulation in human cells DA - 2019/12// PY - 2019/12// DO - 10.1038/s41587-019-0235-7 VL - 37 IS - 12 SP - 1493-+ SN - 1546-1696 ER - TY - JOUR TI - Understanding Polymorph Selection of Sulfamerazine in Solution AU - Liu, Chengxiang AU - Cao, Fengjuan AU - Kulkarni, Samir A. AU - Wood, Geoffrey P. F. AU - Santiso, Erik E. T2 - CRYSTAL GROWTH & DESIGN AB - Polymorphism can have a significant impact on important physical and chemical properties of pharmaceutical products. Empirical screening of polymorphs by using different solvent systems is often labor intensive and time-consuming and is not guaranteed to find the most favorable polymorph for the given application. On the other hand, molecular modeling is a useful tool to study how solvents affect polymorphism, as it provides molecular-level information on the factors governing nucleation, but a number of challenges still remain due to the time scales involved. In the present study we have used a combined modeling and experimental approach to study the nucleation of sulfamerazine in different solvents. Using the string method in collective variables with predefined order parameters, we obtained the nucleation energy barrier of two polymorphs of sulfamerazine in three solvents: acetonitrile, methanol, and water. The energy barrier obtained for form I is lower in all of these solvents than that of form II, which is consistent with our experimental PXRD results. This is a direct observation consistent with the Ostwald rule of stages and the Stranski/Totomanow conjecture. We also carried out crystallization induction time measurements and found that our model correctly ranks the nucleation rates in the solvents studied. Our approach provides a route for computational screening of solvents for crystallization of pharmaceutical compounds. DA - 2019/12// PY - 2019/12// DO - 10.1021/acs.cgd.9b00576 VL - 19 IS - 12 SP - 6925-6934 SN - 1528-7505 ER - TY - JOUR TI - Experiments and finite element modeling of hydrodynamics and mass transfer for continuous gas-to-liquid biocatalysis using a biocomposite falling film reactor AU - Schulte, Mark J. AU - Robinett, Michael AU - Weidle, Nick AU - Duran, Christopher J. AU - Flickinger, Michael C. T2 - CHEMICAL ENGINEERING SCIENCE AB - We investigated the hydrodynamics and mass transfer performance of falling liquid films over a rough, hydrophilic paper surface with experiments and finite element modeling. These results are critical for designing a novel gas-to-liquid continuous bioreactor with cells immobilized on the vertical surface of a paper biocomposite. The paper substrate allows investigations at very low Reynolds numbers while maintaining an unbroken liquid film. A finite element model was developed to give 10 fold faster simulation result for designing a prototype laboratory scale bioreactor. Excellent agreement was found in both the film properties and mass transfer performance between experiments and simulations. At Re < 100, mass transfer coefficients kL and kLa were ∼1E-4 m/s and ∼1000 h−1, respectively, at ∼10 W/m3. That power input is 10–1000 fold less than most gas stripping bioreactors. This work highlights the potential of this finite element method for falling film, gas absorbing, bioreactor design and analysis. DA - 2019/12/14/ PY - 2019/12/14/ DO - 10.1016/j.ces.2019.115163 VL - 209 SP - SN - 1873-4405 KW - Falling film KW - Computational fluid dynamics KW - Gas-to-liquid mass transfer KW - Biocomposite biocatalyst KW - Process intensification KW - Immobilized cells in biocomposites ER - TY - JOUR TI - Screening Yeast Display Libraries against Magnetized Yeast Cell Targets Enables Efficient Isolation of Membrane Protein Binders AU - Bacon, Kaitlyn AU - Burroughs, Matthew AU - Blain, Abigail AU - Menegatti, Stefano AU - Rao, Balaji M. T2 - ACS COMBINATORIAL SCIENCE AB - When isolating binders from yeast displayed combinatorial libraries, a soluble, recombinantly expressed form of the target protein is typically utilized. As an alternative, we describe the use of target proteins displayed as surface fusions on magnetized yeast cells. In our strategy, the target protein is coexpressed on the yeast surface with an iron oxide binding protein; incubation of these yeast cells with iron oxide nanoparticles results in their magnetization. Subsequently, binder cells that interact with the magnetized target cells can be isolated using a magnet. Using a known binder–target pair with modest binding affinity (KD ≈ 400 nM), we showed that a binder present at low frequency (1 in 105) could be enriched more than 100-fold, in a single round of screening, suggesting feasibility of screening combinatorial libraries. Subsequently, we screened yeast display libraries of Sso7d and nanobody variants against yeast displayed targets to isolate binders specific to the cytosolic domain of the mitochondrial membrane protein TOM22 (KD ≈ 272–1934 nM) and the extracellular domain of the c-Kit receptor (KD ≈ 93 to KD > 2000 nM). Additional studies showed that the TOM22 binders identified using this approach could be used for the enrichment of mitochondria from cell lysates, thereby confirming binding to the native mitochondrial protein. The ease of expressing a membrane protein or a domain thereof as a yeast cell surface fusion—in contrast to recombinant soluble expression—makes the use of yeast-displayed targets particularly attractive. Therefore, we expect the use of magnetized yeast cell targets will enable efficient isolation of binders to membrane proteins. DA - 2019/12// PY - 2019/12// DO - 10.1021/acscombsci.9b00147 VL - 21 IS - 12 SP - 817-832 SN - 2156-8944 KW - yeast magnetization KW - combinatorial library screening KW - ligand discovery KW - yeast surface display KW - membrane protein KW - Sso7d KW - nanobody ER - TY - JOUR TI - Inherently self-sterilizing charged multiblock polymers that kill drug-resistant microbes in minutes AU - Peddinti, Bharadwaja S. T. AU - Scholle, Frank AU - Vargas, Mariana G. AU - Smith, Steven D. AU - Ghiladi, Reza A. AU - Spontak, Richard J. T2 - MATERIALS HORIZONS AB - To combat the growing global healthcare threat from drug-resistant pathogens, we demonstrate that midblock-sulfonated block polymers can kill 99.9999% of “superbugs,” including bacteria and viruses, in just 5 minutes due to an abrupt pH reduction. DA - 2019/12/1/ PY - 2019/12/1/ DO - 10.1039/c9mh00726a VL - 6 IS - 10 SP - 2056-2062 SN - 2051-6355 ER - TY - JOUR TI - Extremely Asymmetrical Acoustic Metasurface Mirror at the Exceptional Point AU - Wang, Xu AU - Fang, Xinsheng AU - Mao, Dongxing AU - Jing, Yun AU - Li, Yong T2 - PHYSICAL REVIEW LETTERS AB - Previous research has attempted to minimize the influence of loss in reflection- and transmission-type acoustic metasurfaces. This Letter shows that, by treating the acoustic metasurface as a non-Hermitian system and by harnessing loss, unconventional wave behaviors that do not exist in lossless metasurfaces can be uncovered. Specifically, we theoretically and experimentally demonstrate a non-Hermitian acoustic metasurface mirror featuring extremely asymmetrical reflection at the exception point. As an example, the metasurface mirror is designed to have high-efficiency retroreflection when the wave comes from one side and near-perfect absorption when the wave comes from the opposite side. This work marries conventional gradient index metasurfaces with the exceptional point from non-Hermitian systems, and it paves the way for identifying new mechanisms and functionalities for wave manipulation. DA - 2019/11/22/ PY - 2019/11/22/ DO - 10.1103/PhysRevLett.123.214302 VL - 123 IS - 21 SP - SN - 1079-7114 ER - TY - JOUR TI - Multiplexed Competitive Screening of One-Bead-One-Component Combinatorial Libraries Using a ClonePix 2 Colony Sorter AU - Lavoie, R. Ashton AU - Fazio, Alice AU - Carbonell, Ruben G. AU - Menegatti, Stefano T2 - INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES AB - Screening solid-phase combinatorial libraries of bioactive compounds against fluorescently labeled target biomolecules is an established technology in ligand and drug discovery. Rarely, however, do screening methods include comprehensive strategies—beyond mere library blocking and competitive screening—to ensure binding selectivity of selected leads. This work presents a method for multiplexed solid-phase peptide library screening using a ClonePix 2 Colony Picker that integrates (i) orthogonal fluorescent labeling for positive selection against a target protein and negative selection against competitor species with (ii) semi-quantitative tracking of target vs. competitor binding for every library bead. The ClonePix 2 technology enables global at-a-glance evaluation and customization of the parameters for bead selection to ensure high affinity and selectivity of the isolated leads. A case study is presented by screening a peptide library against green-labeled human immunoglobulin G (IgG) and red-labeled host cell proteins (HCPs) using ClonePix 2 to select HCP-binding ligands for flow-through chromatography applications. Using this approach, 79 peptide ligand candidates (6.6% of the total number of ligands screened) were identified as potential HCP-selective ligands, enabling a potential rate of >3,000 library beads screened per hour. DA - 2019/10/2/ PY - 2019/10/2/ DO - 10.3390/ijms20205119 VL - 20 IS - 20 SP - SN - 1422-0067 KW - library screening KW - bioactive peptides KW - ligand development KW - affinity chromatography KW - affinity ligand KW - ClonePix 2 ER - TY - JOUR TI - Experimental synthesis and characterization of rough particles for colloidal and granular rheology AU - Hsiao, Lilian C. AU - Pradeep, Shravan T2 - CURRENT OPINION IN COLLOID & INTERFACE SCIENCE AB - We review the experimental synthesis of smooth and rough particles, characterization of surface roughness, quantification of the pairwise and bulk friction coefficients, and their effect on the rheology of wet particulate flows. Even in the absence of interparticle attraction or cohesion, such types of flows are broadly ubiquitous, spanning enormous length scales ranging from consumer and food products to earth movements. The increasing availability of model frictional particles is useful to advancing new understanding of particulate rheology. Although hard-sphere particles remain the most widely studied system due to their simplicity, their rigid and frictionless nature cannot predict many of the complex flow phenomena in colloidal and granular suspensions. Besides a myriad of interparticle forces, the presence of tangential interparticle friction arising from either hydrodynamics or solid contacts of asperities is now thought to be responsible for commonalities in shear thickening and jamming phenomena at high volume fractions and shear stresses. The overall richness of the suspension mechanics landscape points to the reunification of colloidal and granular physics in the near future: one in which it may become possible to apply a universal set of physical frameworks to understand the flows of model rough particles across multiple spatiotemporal scales. This can only be accomplished by properly distinguishing between microscopic and bulk friction and by decoupling hydrodynamics and contact contributions within the context of experimental observations. DA - 2019/10// PY - 2019/10// DO - 10.1016/j.cocis.2019.04.003 VL - 43 SP - 94-112 SN - 1879-0399 KW - Rough particles KW - Colloidal suspensions KW - Granular suspensions KW - Hydrodynamics KW - Friction KW - Rheology ER - TY - JOUR TI - Composite double network hydrogels with thermoresponsive colloidal nanoemulsions AU - Kass, Lauren AU - Cardenas‐Vasquez, Ernesto Daniel AU - Hsiao, Lilian C. T2 - AIChE Journal AB - Abstract We report the formulation and mechanical characterization of double network (DN) composite hydrogels. The first network consists of covalently crosslinked poly(ethylene glycol diacrylate) (PEGDA), which forms a strong, brittle network that provides elasticity to the gel. The second network, sodium alginate, is ionically crosslinked with Ca 2+ to allow increased dissipation of mechanical energy. The novelty of this system over existing DN hydrogels is the additional incorporation of a third mesoscale network, composed of thermoresponsive poly(dimethyl siloxane) (PDMS) nanoemulsions, which undergo colloidal gelation through the bridging of the PEGDA hydrophobic end groups into the PDMS droplets. The colloidally gelled microstructures are photopolymerized into a solid hydrogel by crosslinking the precursors with ultraviolet (UV) light. Tensile mechanical experiments performed on the crosslinked DN nanoemulsion hydrogels show that their rupture stress (0.17–0.34 MPa), fracture energy (144–421 J/m 2 ), and Young's modulus (1–2.1 MPa) are comparable to similar systems in the literature. These mechanical measurements suggest that the gels may be suitable for manufacturing processes in which large shear rates and deformations are encountered. DA - 2019/11/5/ PY - 2019/11/5/ DO - 10.1002/aic.16817 VL - 65 IS - 12 SP - e16817 SN - 0001-1541 1547-5905 UR - http://dx.doi.org/10.1002/aic.16817 KW - composite hydrogels KW - double network hydrogels KW - nanoemulsions KW - thermoresponsive ER - TY - JOUR TI - Cellulose Silica Hybrid Nanofiber Aerogels: From Sol–Gel Electrospun Nanofibers to Multifunctional Aerogels T2 - Advanced Functional Materials AB - Abstract Aerogels are considered ideal candidates for various applications, because of their low bulk density, highly porous nature, and functional performance. However, the time intensive nature of the complex fabrication process limits their potential application in various fields. Recently, incorporation of a fibrous network has resulted in production of aerogels with improved properties and functionalities. A facile approach is presented to fabricate hybrid sol–gel electrospun silica‐cellulose diacetate (CDA)‐based nanofibers to generate thermally and mechanically stable nanofiber aerogels. Thermal treatment results in gluing the silica‐CDA network strongly together thereby enhancing aerogel mechanical stability and hydrophobicity without compromising their highly porous nature (>98%) and low bulk density (≈10 mg cm −3 ). X‐ray photoelectron spectroscopy and in situ Fourier‐transform infrared studies demonstrate the development of strong bonds between silica and the CDA network, which result in the fabrication of cross‐linked structure responsible for their mechanical and thermal robustness and enhanced affinity for oils. Superhydrophobic nature and high oleophilicity of the hybrid aerogels enable them to be ideal candidates for oil spill cleaning, while their flame retardancy and low thermal conductivity can be explored in various applications requiring stability at high temperatures. DA - 2019/12/9/ PY - 2019/12/9/ DO - 10.1002/adfm.201907359 UR - http://dx.doi.org/10.1002/adfm.201907359 KW - 3D nanofibers KW - flame retardant KW - nanofiber aerogels KW - oil-water separation KW - polymer-silica hybrid KW - resilient and flexible ER - TY - JOUR TI - Soft dendritic microparticles with unusual adhesion and structuring properties AU - Roh, Sangchul AU - Williams, Austin H. AU - Bang, Rachel S. AU - Stoyanov, Simeon D. AU - Velev, Orlin D. T2 - NATURE MATERIALS DA - 2019/12// PY - 2019/12// DO - 10.1038/s41563-019-0508-z VL - 18 IS - 12 SP - 1315-+ SN - 1476-4660 ER - TY - JOUR TI - Liquid Metal Nanoparticles as Initiators for Radical Polymerization of Vinyl Monomers AU - Ma, Jinwoo AU - Lin, Yiliang AU - Kim, Yong-Woo AU - Ko, Yeongun AU - Kim, Jongbeom AU - Oh, Kyu Hwan AU - Sun, Jeong-Yun AU - Gorman, Christopher B. AU - Voinov, Maxim A. AU - Smirnov, Alex I. AU - Genzer, Jan AU - Dickey, Michael D. T2 - ACS MACRO LETTERS AB - Sonication of gallium or gallium-based liquid metals in an aqueous solution of vinyl monomers leads to rapid free radical polymerization (FRP), without the need for conventional molecular initiators. Under ambient conditions, a passivating native oxide separates these metals from solution and renders the metal effectively inert. However, sonication generates liquid metal nanoparticles (LMNPs) of ∼100 nm diameter and thereby increases the surface area of the metal. The exposed metal initiates polymerization, which proceeds via a FRP mechanism and yields high molecular weight polymers that can form physical gels. Spin trapping EPR reveals the generation of free radicals. Time-of-flight secondary ion mass spectrometry measurements confirm direct polymer bonding to gallium, verifying the formation of surface-anchored polymer grafts. The grafted polymers can modify the interfacial properties, that is, the preference of the metal particles to disperse in aqueous versus organic phases. The polymer can also be degrafted and isolated from the particles using strong acid or base. The concept of physically disrupting passivated metal surfaces offers new routes for surface-initiated polymerization and has implications for surface modification, reduction reactions, and fabrication of mechanically responsive materials. DA - 2019/11// PY - 2019/11// DO - 10.1021/acsmacrolett.9b00783 VL - 8 IS - 11 SP - 1522-1527 SN - 2161-1653 ER - TY - JOUR TI - Mechanochromic composite elastomers for additive manufacturing and low strain mechanophore activation AU - Rohde, Rachel C. AU - Basu, Amrita AU - Okello, Lilian B. AU - Barbee, Meredith H. AU - Zhang, Yudi AU - Velev, Orlin D. AU - Nelson, Alshakim AU - Craig, Stephen L. T2 - POLYMER CHEMISTRY AB - Composite silicone inks provide access to 3D-printable elastomers that are mechanochemically active at lower strains that single component analogs. DA - 2019/11/28/ PY - 2019/11/28/ DO - 10.1039/c9py01053j VL - 10 IS - 44 SP - 5985-5991 SN - 1759-9962 ER - TY - JOUR TI - Light-Induced Structuring of Photosensitive Polymer Brushes AU - Kopyshev, Alexey AU - Kanevche, Katerina AU - Lomadze, Nino AU - Pfitzner, Emanuel AU - Loebner, Sarah AU - Patil, Rohan R. AU - Genzer, Jan AU - Heberle, Joachim AU - Santer, Svetlana T2 - ACS APPLIED POLYMER MATERIALS AB - We investigate light-induced irreversible structuring of surface topographies in poly(3-sulfopropyl methacrylate/potassium salt) (PSPMK) brushes on flat solid substrates prepared by surface-initiated atom transfer radical polymerization. The brushes have been loaded with azobenzene-based surfactant comprised of positively charged headgroups and hydrophobic tail. The surfactant exhibits photoresponsive properties through photoisomerization from the trans to cis states leading to significant changes in physicochemical properties of grafted polymer chains. The azobenzene surfactant enables photoresponsive behavior without introducing irreversible changes to chemical composition of the parent polymer brush. Exposing these photosensitive brushes to irradiation with UV interference beams causes the polymer brush to form surface relief grating (SRG) patterns. The cationic surfactant penetrates only ∼25% of the upper portion of the PSPMK brush, resulting in the formation of two sections within the brush: a photoresponsive upper layer and nonfunctional buried layer, which is not affected by the UV irradiation. Using nano-FTIR spectroscopy, we characterize locally the chemical composition of the polymer brush and confirm partial penetration of the surfactant within the film. Strong optomechanical stresses take place only within the upper layer of the brush that is impregnated with the surfactants and causes surface topography alternation due to a local rupture of grafted polymer chains. The cleaved polymer chains are then removed from the surface by using a good solvent, leaving behind topographical grating on top of the nonfunctional brush layer. We demonstrate that photostructured polymer brush can be used for reversible switching of brush topography by varying external humidity. DA - 2019/11// PY - 2019/11// DO - 10.1021/acsapm.9b00705 VL - 1 IS - 11 SP - 301-3026 SN - 2637-6105 KW - photosensitive polymer brushes KW - reversible and irreversible structuring of polymer brushes KW - photosensitive azobenzene containing surfactant KW - strong polyelectrolyte brush KW - SRG formation in polymer brushes ER - TY - JOUR TI - Electrospun Polymer Nanofibers as Seed Coatings for Crop Protection AU - Farias, Barbara V. AU - Pirzada, Tahira AU - Mathew, Reny AU - Sit, Tim L. AU - Opperman, Charles AU - Khan, Saad A. T2 - ACS Sustainable Chemistry & Engineering AB - Ineffective delivery of pesticides leads to multiple application cycles of active ingredients (AIs), resulting in increased cost while endangering the environment via soil, water, and air contamination. Herein, we present a facile approach for localized delivery of pesticides by coating seeds with electrospun cellulose diacetate (CDA) nanofibers containing abamectin or fluopyram as model AIs. CDA is used as the polymer of choice because of its good electrospinnability, low water solubility, and eventual biodegradability. Nanofibrous coatings are directly electrospun onto soybean seeds and show no deleterious effects on seed germination regardless of coating thickness and uniformity. Water dissolution studies show that nanofibers maintain their integrity for over 2 weeks, a necessary characteristic to make this approach effective. AI release studies display a slow and sustained release of both abamectin and fluopyram from the nanofibers, with abamectin exhibiting a slower release because of its more hydrophobic nature and possibly stronger interaction with CDA. Functional performance, tested using fluopyram-loaded nanofibers in an in vitro fungal assay against the plant pathogen Alternaria lineariae, consistently inhibits fungal growth. The sustained release profile taken together with moisture stability suggests that nanofibrous seed coatings have a strong potential as an alternative platform to control plant pathogens such as nematodes and fungi. DA - 2019/12/16/ PY - 2019/12/16/ DO - 10.1021/acssuschemeng.9b05200 VL - 7 IS - 24 SP - 19848-19856 UR - https://doi.org/10.1021/acssuschemeng.9b05200 KW - electrospinning KW - seed coating KW - cellulose KW - fluopyram KW - abamectin KW - controlled release ER - TY - JOUR TI - Extreme thermophiles as emerging metabolic engineering platforms AU - Crosby, James R AU - Laemthong, Tunyaboon AU - Lewis, April M AU - Straub, Christopher T AU - Adams, Michael WW AU - Kelly, Robert M T2 - Current Opinion in Biotechnology AB - Going forward, industrial biotechnology must consider non-model metabolic engineering platforms if it is to have maximal impact. This will include microorganisms that natively possess strategic physiological and metabolic features but lack either molecular genetic tools or such tools are rudimentary, requiring further development. If non-model platforms are successfully deployed, new avenues for production of fuels and chemicals from renewable feedstocks or waste materials will emerge. Here, the challenges and opportunities for extreme thermophiles as metabolic engineering platforms are discussed. DA - 2019/10// PY - 2019/10// DO - 10.1016/j.copbio.2019.02.006 VL - 59 SP - 55-64 J2 - Current Opinion in Biotechnology LA - en OP - SN - 0958-1669 UR - http://dx.doi.org/10.1016/j.copbio.2019.02.006 DB - Crossref ER - TY - JOUR TI - Intensified Ethylene Production via Chemical Looping through an Exergetically Efficient Redox Scheme AU - Neal, Luke M. AU - Haribal, Vasudev Pralhad AU - Li, Fanxing T2 - ISCIENCE AB - Ethylene production via steam cracking of ethane and naphtha is one of the most energy and emission-intensive processes in the chemical industry. High operating temperatures, significant reaction endothermicity, and complex separations create hefty energy demands and result in substantial CO2 and NOx emissions. Meanwhile, decades of optimization have led to a thermally efficient, near-"perfect" process with ∼95% first law energy efficiency, leaving little room for further reduction in energy consumption and CO2 emissions. In this study, we demonstrate a transformational chemical looping-oxidative dehydrogenation (CL-ODH) process that offers 60%-87% emission reduction through exergy optimization. Through detailed exergy analyses, we show that CL-ODH leads to exergy savings of up to 58% in the upstream reactors and 26% in downstream separations. The feasibility of CL-ODH is supported by a robust redox catalyst that demonstrates stable activity and selectivity for over 1,400 redox cycles in a laboratory-scale fluidized bed reactor. DA - 2019/9/27/ PY - 2019/9/27/ DO - 10.1016/j.isci.2019.08.039 VL - 19 SP - 894-+ SN - 2589-0042 UR - https://doi.org/10.1016/j.isci.2019.08.039 ER - TY - JOUR TI - Flow dynamics of concentrated starlike micelles: A superposition rheometry investigation into relaxation mechanisms AU - Jacob, Alan R. AU - Poulos, Andreas S. AU - Semenov, Alexander N. AU - Vermant, Jan AU - Petekidis, George T2 - JOURNAL OF RHEOLOGY AB - The steady state flow of a concentrated dispersion of starlike micelles above the colloidal glass transition concentration is interrogated by superimposing a small amplitude straining motion orthogonal to the main flow direction. Strain amplitude sweeps reveal that the linear response region of the orthogonal perturbation increases with increasing flow rate, consistent with a fluidization of the materials. Orthogonal dynamic frequency sweeps (ODFSs) are obtained for a wide range of shear rates probing the full flow curve. The shear-induced fluidization of the initially glassy suspension is more clearly evidenced by the appearance of a crossover frequency ωc in ODFS, which steadily increases, reflecting a faster structural relaxation under shear. The dependence of ωc on the shear rate is sublinear and follows a power law with an exponent of 0.8. We show that the shape of the orthogonal viscoelastic spectrum changes at a critical shear rate γ˙cr, indicative of a structural relaxation modulus that changes from exponential at lower shear rates to multistep with alternating exponential and power law response at higher shear rates. We finally provide a theoretical framework which explains the observed sublinear power law dependence of the crossover frequency and relates it with the shear rate dependence of the viscosity measured by the flow curve. DA - 2019/7// PY - 2019/7// DO - 10.1122/1.5086022 VL - 63 IS - 4 SP - 641-653 SN - 1520-8516 ER - TY - JOUR TI - Mechanochemical Degrafting of a Surface-Tethered Poly(acrylic acid) Brush Promoted Etching of Its Underlying Silicon Substrate AU - Li, Yuanchao AU - Lin, Yiliang AU - Dai, Yunkai AU - Ko, Yeongun AU - Genzer, Jan T2 - LANGMUIR AB - The stability of surface-tethered polyelectrolyte brushes has been investigated during the past few years. We have previously reported on the degrafting of poly(acrylic acid) (PAA) polymer brushes from flat silicon substrates. Here, we present a detailed study on the effects of NaCl concentration and the grafting density and molecular weight on the stability of PAA brushes during incubation in 0.1 M ethanolamine buffer (pH 9.0) solutions. Without NaCl in the buffer solution, the PAA brushes remain intact. Adding NaCl facilitates etching of the substrate due to accelerating dissolution of the top silica layer and promoting degrafting of the PAA chains. The PAA grafting density and molecular weight play an important role in the substrate etching by affecting the penetration barrier and local concentration of the etchants. We also tested the stability of self-assembled monolayers (SAMs) made of hydrophobic alkyltrichlorosilanes anchored on silicon substrates. The results demonstrated that the SAMs were too thin to protect the substrates from etching, in contrast to thick poly(methyl methacrylate) brushes. Our findings suggest that both polymer brushes (especially polyelectrolyte brushes) and SAMs anchored to silicon substrates may undergo erosion/etching on the substrates in basic environments, which compromises their stability and therefore jeopardizes their applications in coating, biosensing, and so forth. DA - 2019/10/22/ PY - 2019/10/22/ DO - 10.1021/acs.langmuir.9b02610 VL - 35 IS - 42 SP - 13693-13699 SN - 0743-7463 ER - TY - JOUR TI - Emergent spatiotemporal dynamics of the actomyosin network in the presence of chemical gradients AU - Miller, Callie J. AU - LaFosse, Paul K. AU - Asokan, Sreeja B. AU - Haugh, Jason M. AU - Bear, James E. AU - Elston, Timothy C. T2 - INTEGRATIVE BIOLOGY AB - We used particle-based computer simulations to study the emergent properties of the actomyosin cytoskeleton. Our model accounted for biophysical interactions between filamentous actin and non-muscle myosin II and was motivated by recent experiments demonstrating that spatial regulation of myosin activity is required for fibroblasts responding to spatial gradients of platelet derived growth factor (PDGF) to undergo chemotaxis. Our simulations revealed the spontaneous formation of actin asters, consistent with the punctate actin structures observed in chemotacting fibroblasts. We performed a systematic analysis of model parameters to identify biochemical steps in myosin activity that significantly affect aster formation and performed simulations in which model parameter values vary spatially to investigate how the model responds to chemical gradients. Interestingly, spatial variations in motor stiffness generated time-dependent behavior of the actomyosin network, in which actin asters continued to spontaneously form and dissociate in different regions of the gradient. Our results should serve as a guide for future experimental investigations. DA - 2019/6// PY - 2019/6// DO - 10.1093/intbio/zyz023 VL - 11 IS - 6 SP - 280-292 SN - 1757-9708 ER - TY - JOUR TI - Effect of Composition on the Molecular Dynamics of Biodegradable Isotactic Polypropylene/Thermoplastic Starch Blends AU - Wozniak-Braszak, Aneta AU - Knitter, Monika AU - Markiewicz, Ewa AU - Ingram, Wade F. AU - Spontak, Richard J. T2 - ACS SUSTAINABLE CHEMISTRY & ENGINEERING AB - Polyolefins such as polypropylene are used in an immensely broad range of commodity products and account for the largest volume of synthetic polymers generated worldwide. For this reason, this family of thermoplastics contributes significantly to solid waste both on land and in the ocean. One viable approach to mitigate this growing problem and simultaneously reduce the cost of and dependence on petroleum-based polymers relies on blends wherein an added biopolymer can promote natural biodegradation. Due to their chemical dissimilarity, however, nonpolar polyolefins and polar biopolymers tend to phase-separate, in which case a fundamental, molecular-level understanding of the role of polymer/polymer interfaces on chain mobility in blends differing in composition is needed. In the present study, the molecular dynamics of blends composed of isotactic polypropylene (iPP) and glycerol-plasticized thermoplastic starch (TPS) are investigated by solid-state proton nuclear magnetic resonance and dielectric relaxation spectroscopies. Blends prepared by twin-screw extrusion range in composition from 10 to 70 wt % TPS, and their morphologies and thermal properties are examined by scanning electron microscopy and differential scanning calorimetry, respectively. This comparative analysis establishes the influence of TPS on the molecular dynamics of biphasic iPP/TPS blends relative to the constituent homopolymers. DA - 2019/10/7/ PY - 2019/10/7/ DO - 10.1021/acssuschemeng.9b02774 VL - 7 IS - 19 SP - 16050-16059 SN - 2168-0485 KW - NMR spectroscopy KW - dielectric relaxation KW - polymer dynamics KW - chain relaxation KW - polymer blends ER - TY - JOUR TI - Barriers to genome editing with CRISPR in bacteria AU - Vento, Justin M. AU - Crook, Nathan AU - Beisel, Chase L. T2 - JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY AB - Abstract Genome editing is essential for probing genotype–phenotype relationships and for enhancing chemical production and phenotypic robustness in industrial bacteria. Currently, the most popular tools for genome editing couple recombineering with DNA cleavage by the CRISPR nuclease Cas9 from Streptococcus pyogenes. Although successful in some model strains, CRISPR-based genome editing has been slow to extend to the multitude of industrially relevant bacteria. In this review, we analyze existing barriers to implementing CRISPR-based editing across diverse bacterial species. We first compare the efficacy of current CRISPR-based editing strategies. Next, we discuss alternatives when the S. pyogenes Cas9 does not yield colonies. Finally, we describe different ways bacteria can evade editing and how elucidating these failure modes can improve CRISPR-based genome editing across strains. Together, this review highlights existing obstacles to CRISPR-based editing in bacteria and offers guidelines to help achieve and enhance editing in a wider range of bacterial species, including non-model strains. DA - 2019/10// PY - 2019/10// DO - 10.1007/s10295-019-02195-1 VL - 46 IS - 9-10 SP - 1327-1341 SN - 1476-5535 UR - https://doi.org/10.1007/s10295-019-02195-1 KW - Bacteria KW - Nuclease KW - Genome editing KW - CRISPR KW - Recombineering ER - TY - JOUR TI - Binding Conductive Ink Initiatively and Strongly: Transparent and Thermally Stable Cellulose Nanopaper as a Promising Substrate for Flexible Electronics T2 - ACS Applied Materials & Interfaces AB - For flexible electronics, the substrates play key roles in ensuring their performance. However, most substrates suffer from weak bonding with the conductive ink and need additional aids. Here, inspired by the Ag–S bond theory, a novel cellulose nanopaper substrate is presented to improve the bond strength with the Ag nanoparticle ink through a facile printing method. The substrate is fabricated using thiol-modified nanofibrillated cellulose and exhibits excellent optical properties (∼85%@550 nm), ultra-small surface roughness (3.47 nm), and high thermal dimensional stability (up to at least 90 °C). Most importantly, it can attract Ag nanoparticles initiatively and bind them firmly, which enable the conductive ink to be printed without using the ink binder and form a strong substrate–ink bonding and maintain a stable conductivity of 2 × 10–4 Ω cm even after extensive peeling and bending. This work may lead to exploring new opportunities to fabricate high-performance flexible electronics using the newly developed nanopaper substrate. DA - 2019/// PY - 2019/// DO - 10.1021/ACSAMI.9B04596 UR - https://publons.com/publon/14480246/ KW - Ag-S bond KW - silver nanoparticles KW - nanofibrillated cellulose KW - nanopaper KW - flexible electronics ER - TY - JOUR TI - Life cycle considerations of solvents AU - Jimenez-Gonzalez, Concepcion T2 - CURRENT OPINION IN GREEN AND SUSTAINABLE CHEMISTRY AB - The most sustainable solvent is the solvent that is not used. However, avoiding the use of solvents is oftentimes not possible, and efforts are needed to minimize their environmental footprint. This includes both minimizing the amount of solvent used and minimizing the impacts across the solvent's life cycle, which include raw material extraction and production, manufacturing, transportation, use, recycling, and final disposal. Evaluating solvents without using a life cycle approach would underestimate impacts, conceal trade-offs, and could result in regrettable substitution. This article discusses key aspects to be considered when evaluating and selecting solvents using a life cycle assessment approach. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.cogsc.2019.02.004 VL - 18 SP - 66-71 SN - 2452-2236 ER - TY - JOUR TI - Modified Ceria for "Low-Temperature" CO2 Utilization: A Chemical Looping Route to Exploit Industrial Waste Heat AU - Haribal, Vasudev Pralhad AU - Wang, Xijun AU - Dudek, Ryan AU - Paulus, Courtney AU - Turk, Brian AU - Gupta, Raghubir AU - Li, Fanxing T2 - ADVANCED ENERGY MATERIALS AB - Abstract Efficient CO 2 utilization is key to limit global climate change. Carbon monoxide, which is a crucial feedstock for chemical synthesis, can be produced by splitting CO 2 . However, existing thermochemical routes are energy intensive requiring high operating temperatures. A hybrid redox process (HRP) involving CO 2 ‐to‐CO conversion using a lattice oxygen‐deprived redox catalyst at relatively low temperatures (<700 °C) is reported. The lattice oxygen of the redox catalyst, restored during CO 2 ‐splitting, is subsequently used to convert methane to syngas. Operated at temperatures significantly lower than a number of industrial waste heat sources, this cyclic redox process allows for efficient waste heat‐utilization to convert CO 2 . To enable the low temperature operation, lanthanum modified ceria (1:1 Ce:La) promoted by rhodium (0.5 wt%) is reported as an effective redox catalyst. Near‐complete CO 2 conversion with a syngas yield of up to 83% at low temperatures is achieved using Rh‐promoted LaCeO 4− x . While La improves low‐temperature bulk redox properties of ceria, Rh considerably enhances the surface catalytic properties for methane activation. Density functional theory calculations further illustrate the underlying functions of La‐substitution. The highly effective redox catalyst and HRP scheme provide a potentially attractive route for chemical production using CO 2 , industrial waste heat, and methane, with appreciably lowered CO 2 emissions. DA - 2019/11// PY - 2019/11// DO - 10.1002/aenm.201901963 VL - 9 IS - 41 SP - SN - 1614-6840 UR - https://doi.org/10.1002/aenm.201901963 KW - chemical looping KW - CO2 utilization KW - redox catalyst KW - reforming KW - syngas ER - TY - JOUR TI - DendriPeps: Expanding Dendrimer Functionality by Hybridizing Poly(amidoamine) (PAMAM) Scaffolds with Peptide Segments AU - Smith, Ryan J. AU - Gorman, Christopher B. AU - Menegatti, Stefano T2 - MACROMOLECULAR RAPID COMMUNICATIONS AB - Abstract In this work, the first synthesis of poly(amidoamine) (PAMAM) dendrimers whose branches are hybridized with peptide segments (DendriPeps) is reported. The intercalation of amino acids within the branches of PAMAMs provides supplementary internal functionalities to the coronal groups. Four DendriPep prototypes are synthesized with lysine or glutamic acid as “guest” amino acids, displaying, respectively, a primary amine or a carboxyl group, on generation (G)2 and G3 PAMAMs as host scaffolds. The precise control over the number, type, and topological placement of functional groups expands the functional behavior of DendriPeps beyond current PAMAM dendrimers toward new frontiers or colloids, drug delivery vectors, and catalysis. DA - 2019/11// PY - 2019/11// DO - 10.1002/marc.201900325 VL - 40 IS - 22 SP - SN - 1521-3927 KW - internally functionalized dendrimers KW - orthogonal protection strategies KW - poly(amidoamine) KW - polymer-peptide chemistry ER - TY - JOUR TI - Shear-Driven Direct-Write Printing of Room-Temperature Gallium-Based Liquid Metal Alloys AU - Cook, Alexander AU - Parekh, Dishit P. AU - Ladd, Collin AU - Kotwal, Gargee AU - Panich, Lazar AU - Durstock, Michael AU - Dickey, Michael D. AU - Tabor, Christopher E. T2 - ADVANCED ENGINEERING MATERIALS AB - Gallium‐based metal alloys have high electrical conductivity in the liquid state at room temperature. These liquid metal conductors inspire unique electronic applications such as reconfigurable circuits and stretchable components with extremely high strain tolerance. Previously, liquid metals have been successfully patterned via direct‐writing, yielding metallically conductive features on‐demand at room temperature that do not require post‐processing, down to a resolution of ≈10 μm. While most direct‐write processes extrude materials from a nozzle via pressure or volumetric displacement, liquid metal is instead printed here by a shear‐driven mechanism that occurs when the oxide‐coated meniscus of the metal adheres to the printing substrate and is “pulled” from the nozzle at pressures that are well‐below that needed to extrude the metal in the absence of shear. Herein, the key operating parameters that enable shear‐driven printing of liquid metals including dispensing pressure, choice of substrate, print height, the surrounding environmental conditions, and the speed and acceleration of the print head are elucidated. A guide to the best practices as well as limitations for implementing shear‐driven printing of liquid metals at room temperature is provided in these studies. DA - 2019/11// PY - 2019/11// DO - 10.1002/adem.201900400 VL - 21 IS - 11 SP - SN - 1527-2648 KW - additive manufacturing KW - direct-writing KW - liquid metals KW - patterning KW - printed electronics ER - TY - JOUR TI - Insights into the solvation and dynamic behaviors of a lithium salt in organic- and ionic liquid-based electrolytes AU - Tong, Jiahuan AU - Xiao, Xingqing AU - Liang, Xiaodong AU - Solms, Nicolas AU - Huo, Feng AU - He, Hongyan AU - Zhang, Suojiang T2 - PHYSICAL CHEMISTRY CHEMICAL PHYSICS AB - New-generation lithium-ion batteries use ionic liquids (ILs) as electrolyte solutions, greatly enhancing the safety and energy storage capacity of the battery. Fundamental molecular insights are useful for understanding the advantages of high conductivity of IL solvent electrolytes over organic solvent ones. In this work, we computationally studied two organic solvents (DMC and DEC) and four IL solvents ([Cnmim][BF4] and [Cnmim][TFSI] (n = 2, 4)) to examine the physicochemical properties of high concentration electrolytes. As expected, the IL solvent electrolytes exhibit higher density and viscosity, and larger self-diffusion coefficients and conductivity than the organic solvent electrolytes. Further, the microstructures of the lithium salt LiTFSI in various solvent electrolytes were investigated to explore the effect of the organic and IL solvents on the ionic association of the ions Li+ and TFSI-. The structural analysis of LiTFSI revealed that the organic solvents restrict the free motion of the ions, reducing the conductivity of the electrolytes. The [BF4]-type IL electrolytes have higher conductivity than the [TFSI]-type IL electrolytes, especially [C4mim][BF4] with the highest conductivity among the IL-based electrolytes. More importantly, it was proved that the dissolution of LiTFSI in the IL solvents is an anion-driven process. DA - 2019/9/21/ PY - 2019/9/21/ DO - 10.1039/c9cp01848d VL - 21 IS - 35 SP - 19216-19225 SN - 1463-9084 ER - TY - JOUR TI - Survival and Habitat of Yellow-Phase American Eels in North Carolina Tidal Creeks AU - Rudershausen, Paul J. AU - Lee, Laura M. AU - Lombardo, Steven M. AU - Merrell, Jeffery H. AU - Buckel, Jeffrey A. T2 - TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY AB - Abstract We estimated rates of survival as well as effects of habitat on catch rates of juvenile yellow‐phase American Eels Anguilla rostrata in southeastern U.S. tidal creeks. We trapped and marked eels with PIT tags at 24 fixed sites in eight North Carolina tidal creeks and then recaptured and resighted the tagged individuals to estimate apparent survival. Separate Cormack–Jolly–Seber ( CJS ) models were fitted to mark–recapture data (eight creeks) versus mark–resight data (four creeks) to estimate apparent survival. Median annual apparent survival (Φ) was higher when the CJS model was fitted to mark–resight data (Φ = 0.15) than to mark–recapture data (Φ = 0.013). Negative binomially distributed models were fitted to catch rates of both tagged and untagged eels to test for habitat, development, and seasonal effects. The presence/absence of culverts and season were meaningful covariates of catch rates; greater catches were found at sites possessing culverts and during the spring. Other habitat and development factors at the site, creek, and watershed levels were not important covariates of catch rates. Partitioning the sources of loss of yellow‐phase American Eels from these systems into mortality versus emigration would be useful future research in the southeastern U.S. coastal region. Further study into how culverts affect yellow‐phase American Eel habitation and movement in southeastern U.S. estuaries is also warranted. DA - 2019/9// PY - 2019/9// DO - 10.1002/tafs.10190 VL - 148 IS - 5 SP - 978-990 SN - 1548-8659 ER - TY - JOUR TI - Morphology and proton diffusion in a coarse-grained model of sulfonated poly(phenylenes) AU - Clark, Jennifer A. AU - Santiso, Erik E. AU - Frischknecht, Amalie L. T2 - JOURNAL OF CHEMICAL PHYSICS AB - A coarse-grained model previously used to simulate Nafion using dissipative particle dynamics (DPD) is modified to describe sulfonated Diels-Alder poly(phenylene) (SDAPP) polymers. The model includes a proton-hopping mechanism similar to the Grotthuss mechanism. The intramolecular parameters for SDAPP are derived from atomistic molecular dynamics (MD) simulation using the iterative Boltzmann inversion. The polymer radii of gyration, domain morphologies, and cluster distributions obtained from our DPD model are in good agreement with previous atomistic MD simulations. As found in the atomistic simulations, the DPD simulations predict that the SDAPP nanophase separates into hydrophobic polymer domains and hydrophilic domains that percolate through the system at sufficiently high sulfonation and hydration levels. Increasing sulfonation and/or hydration leads to larger proton and water diffusion constants, in agreement with experimental measurements in SDAPP. In the DPD simulations, the proton hopping (Grotthuss) mechanism becomes important as sulfonation and hydration increase, in qualitative agreement with experiment. The turning on of the hopping mechanism also roughly correlates with the point at which the DPD simulations exhibit clear percolated, hydrophilic domains, demonstrating the important effects of morphology on proton transport. DA - 2019/9/14/ PY - 2019/9/14/ DO - 10.1063/1.5116684 VL - 151 IS - 10 SP - SN - 1089-7690 ER - TY - JOUR TI - Determining Water Sorption and Desorption in Thin Hydrophilic Polymer Films by Thermal Treatment AU - Ko, Yeongun AU - Miles, Jason R. AU - Genzer, Jan T2 - ACS APPLIED POLYMER MATERIALS AB - Knowledge of dry thickness of polymer films is required to determine the areal density of polymeric grafts and the degree of swelling of polymer networks and surface-anchored polymer assemblies. Because hydrophilic polymer films absorb water at ambient conditions and retain it, it is challenging to establish accurate dry thickness in such systems. Here we report on determining water uptake by chargeable/charged polymer films by monitoring the coefficient of thermal expansion (CTE) and thermo-optic coefficient (TOC) using ellipsometry. Knowing accurate amount of moisture in polymer films is needed for numerous applications, including, humidity and temperature sensors, polymer nanoreactors, lubricating coatings, antibacterial surfaces, and many others. DA - 2019/9// PY - 2019/9// DO - 10.1021/acsapm.9b00607 VL - 1 IS - 9 SP - 2495-2502 SN - 2637-6105 KW - polymer film KW - ellipsometry KW - dry thickness KW - moisture KW - charge density KW - CTE KW - TOC ER - TY - JOUR TI - Chemical Looping Co-splitting of H2O-CO2 for Efficient Generation of Syngas AU - Chen, Yanpeng AU - Zhu, Xing AU - Li, Kongzhai AU - Wei, Yonggang AU - Zheng, Yane AU - Wang, Hua T2 - ACS SUSTAINABLE CHEMISTRY & ENGINEERING AB - Syngas generation via thermochemical H2O–CO2 splitting relies heavily on a high-temperature decomposition of metal oxides into a reduced state. Meanwhile, typical chemical looping partial oxidation of methane to syngas suffers from the carbon deposition and the low selectivity toward syngas. To overcome these drawbacks, the partial oxidation of methane and H2O–CO2 splitting are coupled to consist of an alternative chemical looping redox scheme for the generation of Fischer–Tropsch (F–T)-ready syngas. The usability of lattice oxygen in a redox catalyst is facilitated, and its redox property is also thermodynamically optimized by using H2O and CO2 as soft oxidants, guaranteeing an effective generation of syngas from both redox steps. The carbon tolerance is greatly enhanced due to H2O or CO2 gasification in the reoxidization step. Experimental studies confirm the redox scheme by using CeO2–LaFeO3 redox catalyst, demonstrating generation of syngas with an H2/CO molar ratio around 2.0 in both methane partial oxidation and H2O–CO2 splitting steps over 30 repeated cycles at 850 °C. A syngas selectivity of 95% in methane partial oxidation and nearly 100% conversion of CO2 to CO can be achieved. Synergistic effect and competing reaction between H2O and CO2 splittings over the reduced redox catalyst are the key factors for the control of syngas composition and the intensification of CO2 splitting. The proposed approach can potentially be applied for production of F–T-ready syngas with an increased yield without the need for gas separation when compared to the state-of-the-art thermochemical splitting or methane chemical looping partial oxidation processes. DA - 2019/9/16/ PY - 2019/9/16/ DO - 10.1021/acssuschemeng.9b02996 VL - 7 IS - 18 SP - 15452-15462 SN - 2168-0485 KW - Chemical looping KW - CO2 splitting KW - Redox KW - Syngas KW - Ceria KW - Perovskite ER - TY - JOUR TI - Towards understanding the moral reasoning process of senior chemical engineering students in process safety contexts AU - Butler, Brittany AU - Bodnar, Cheryl AU - Cooper, Matthew AU - Burkey, Daniel AU - Anastasio, Daniel T2 - EDUCATION FOR CHEMICAL ENGINEERS AB - Despite process safety and ethical decision making being recognized priorities in many chemical companies, process safety incidents continue to occur with unfortunate regularity. In order to understand why such incidents keep occurring, and to prevent future accidents from happening, it is important to study the decision-making habits of people employed at chemical companies, and to inform students of the difference between the influences of ethics and behavioral ethics in process safety decision making. This study seeks to determine how senior chemical engineering students approach reasoning through process safety scenarios through the use of a mixed methods study. This study found that four out of the five students who participated in the study demonstrated post-conventional reasoning, and the remaining student showed conventional reasoning based on the quantitative analysis of their responses. Students showed mostly post-conventional reasoning in their responses based on a qualitative analysis; however, through comparison of these results it was found that the moral schema students were classified as was not always truly representative of their moral reasoning. DA - 2019/7// PY - 2019/7// DO - 10.1016/j.ece.2019.03.004 VL - 28 SP - 1-12 SN - 1749-7728 KW - Students assessment KW - Mixed-methods study KW - Ethics KW - Students perception KW - Senior undergraduate ER - TY - JOUR TI - Recent Advances in Intensified Ethylene Production-A Review AU - Gao, Yunfei AU - Neal, Luke AU - Ding, Dong AU - Wu, Wei AU - Baroi, Chinmoy AU - Gaffney, Anne M. AU - Li, Fanxing T2 - ACS CATALYSIS AB - Steam cracking is a well-established commercial technology for ethylene production. Despite decades of optimization efforts, the process is, nevertheless, highly energy and carbon intensive. This review covers the recent advances in alternative approaches that hold promise in the intensification of ethylene production from hydrocarbon feedstocks ranging from methane to naphtha. Oxidative as well as nonoxidative approaches using conventional, chemical looping, membrane, electrochemical, and plasma-assisted systems are discussed. We note that catalysts, electrocatalysts, and/or redox catalysts play critical roles in the performance of these alternative ethylene production technologies. Meanwhile, the complexity in producing polymer-grade ethylene also requires comprehensive considerations of not only (catalytic) reactions for ethylene formation but also feedstock preparation (e.g., air separation for oxidative conversion) and product separations. Although these alternative technologies have yet to be commercially implemented, a number of oxidative approaches have shown promise for close to order-of-magnitude reduction in energy consumption and CO2 emissions in comparison to steam cracking. Given the substantial progress in these research areas and the significant increase in C1 and C2 supplies resulting from the US shale gas revolution, we are excited by the enormous opportunities and potential impacts in the advancement and eventual implementation of significantly intensified ethylene production technologies. DA - 2019/9// PY - 2019/9// DO - 10.1021/acscatal.9b02922 VL - 9 IS - 9 SP - 8592-8621 SN - 2155-5435 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85071911366&partnerID=MN8TOARS KW - ethylene KW - process intensification KW - oxidative coupling of methane KW - oxidative dehydrogenation KW - chemical looping KW - electrochemical ethylene production ER - TY - JOUR TI - Nanostructured MoOx films deposited on c-plane sapphire AU - Novotny, Petr AU - Lamb, H. Henry T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Molybdenum oxide films were deposited on α-Al2O3 (0001) at 580 °C using MoO3 from a conventional molecular beam epitaxy Knudsen cell. A relatively smooth film (RMS roughness 1.1 nm) was deposited in 1 min at 580 °C using a Knudsen cell temperature of 620 °C; however, after 15 min deposition under these conditions, isolated islands (30–50 nm wide × 10–20 nm tall) develop that are stable to annealing at 600 °C for 60 min. XPS evidenced that the films are oxygen deficient with an average formula of MoO2.7. The authors infer that this oxygen deficiency is responsible for their thermal stability and may have significant effects on their catalytic and electronic properties. In contrast, stoichiometric MoO3 films deposited at 400 °C sublime completely during annealing at 600 °C. DA - 2019/9// PY - 2019/9// DO - 10.1116/1.5100752 VL - 37 IS - 5 SP - SN - 1520-8559 ER - TY - JOUR TI - Translating antibody-binding peptides into peptoid ligands with improved affinity and stability AU - Bordelon, Tee AU - Bobay, Benjamin AU - Murphy, Andrew AU - Reese, Hannah AU - Shanahan, Calvin AU - Odeh, Fuad AU - Broussard, Amanda AU - Kormos, Chad AU - Menegatti, Stefano T2 - JOURNAL OF CHROMATOGRAPHY A AB - A great number of protein-binding peptides are known and utilized as drugs, diagnostic reagents, and affinity ligands. Recently, however, peptide mimetics have been proposed as valuable alternative to peptides by virtue of their excellent biorecognition activity and higher biochemical stability. This poses the need to develop a strategy for translating known protein-binding peptides into peptoid analogues with comparable or better affinity. This work proposes a route for translation utilizing the IgG-binding peptide HWRGWV as reference sequence. An ensemble of peptoid analogues of HWRGWV were produced by adjusting the number and sequence arrangement of residues containing functional groups that resemble both natural and non-natural amino acids. The variants were initially screened via IgG binding tests in non-competitive mode to select candidate ligands. A set of selected peptoids were studied in silico by docking onto putative binding sites identified on the crystal structures of human IgG1, IgG2, IgG3, and IgG4 subclasses, returning values of predicted binding energy that aligned well with the binding data. Selected peptoids PL-16 and PL-22 were further characterized by binding isotherm analysis to determine maximum capacity (Qmax ˜ 48–57 mg of IgG per mL of adsorbent) and binding strength on solid phase (KD ˜ 5.4–7.8 10−7 M). Adsorbents PL-16-Workbeads and PL-22-Workbeads were used for purifying human IgG from a cell culture supernatant added with bovine serum, affording high values of IgG recovery (up to 85%) and purity (up to 98%) under optimized binding and elution conditions. Both peptoid ligands also proved to be stable against proteolytic enzymes and strong alkaline agents. Collectively, these studies form a method guiding the design of peptoid variants of cognate peptide ligands, and help addressing the challenges that, despite the structural similarity, the peptide-to-peptoid translation presents. DA - 2019/9/27/ PY - 2019/9/27/ DO - 10.1016/j.chroma.2019.05.047 VL - 1602 SP - 284-299 SN - 1873-3778 KW - Peptoid ligands KW - Molecular docking KW - Affinity chromatography KW - Antibodies KW - Protein A mimetic ER - TY - JOUR TI - BODIPY-embedded electrospun materials in antimicrobial photodynamic inactivation AU - Stoll, Kevin R. AU - Scholle, Frank AU - Zhu, Jiadeng AU - Zhang, Xiangwu AU - Ghiladi, Reza A. T2 - PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES DA - 2019/8/1/ PY - 2019/8/1/ DO - 10.1039/c9pp00103d VL - 18 IS - 8 SP - 1923-1932 SN - 1474-9092 UR - https://publons.com/publon/26924633/ ER - TY - JOUR TI - Spontaneous Degrafting of Weak and Strong Polycationic Brushes in Aqueous Buffer Solutions AU - Ko, Yeongun AU - Genzer, Jan T2 - MACROMOLECULES AB - Polymers grafted to substrates have traditionally been considered stable because of the covalent bonds that hold the polymers attached to the substrate. However, several recent reports have indicated that grafted polymers may detach from substrates under specific conditions. In this work, we report on a systematic study of polymer degrafting involving polycationic brushes with different degrees of quaternization (DQ, mol %), which have been incubated in three different buffer solutions (pH 4, 7.4, and 9) with the same ionic strength of 0.05 M. We have varied the molecular weight (MW) and grafting density (σ) of the polymer brushes using a combinatorial setup to examine the effect of MW, σ, and DQ on polymer degrafting. Furthermore, we explored the effect of the bonding environment at the base of the initiator (mono- vs. tri-functional) of the grafted polymer layer at the substrate on the overall stability of polymer brushes on the substrate. The two major findings in this paper are (1) degrafting of polycationic grafts from flat silica substrate increases with increasing DQ of the polymer and (2) polymer degrafting likely occurs both in the initiator ester group and the silane head-group at the silicon substrate. DA - 2019/8/27/ PY - 2019/8/27/ DO - 10.1021/acs.macromol.9b01362 VL - 52 IS - 16 SP - 6192-6200 SN - 1520-5835 ER - TY - JOUR TI - Aptamer-Based Fluorescent Sensor Array for Multiplexed Detection of Cyanotoxins on a Smartphone AU - Li, Zheng AU - Zhang, Shengwei AU - Yu, Tao AU - Dai, Zhiming AU - Wei, Qingshan T2 - ANALYTICAL CHEMISTRY AB - Developing easy-to-use and miniaturized detectors is essential for in-field monitoring of environmentally hazardous substances, such as the cyanotoxins. We demonstrated a differential fluorescent sensor array made of aptamers and single-stranded DNA (ssDNA) dyes for multiplexed detection and discrimination of four common cyanotoxins with an ordinary smartphone within 5 min of reaction. The assay reagents were preloaded and dried in a microfluidic chip with a long shelf life over 60 days. Upon the addition of analyte solutions, competitive binding of cyanotoxin to the specific aptamer-dye conjugate occurred. A zone-specific and concentration-dependent reduction in the green fluorescence was observed as a result of the aptamer conformation change. The aptasensors are fully optimized by quantification of their dissociation constants, tuning the stoichiometric ratios of reaction mixtures, and implementation of an internal intensity correction step. The fluorescent sensor array allowed for accurate identification and measurement of four important cyanotoxins, including anatoxin-a (ATX), cylindrospermopsin (CYN), nodularin (NOD), and microcystin-LR (MC-LR), in parallel, with the limit of detection (LOD) down to a few nanomolar (<3 nM), which is close to the World Health Organization’s guideline for the maximum concentration allowed in drinking water. The smartphone-based sensor platform also showed remarkable chemical specificity against potential interfering agents in water. The performance of the system was tested and validated with real lake water samples that were contaminated with trace levels of individual cyanotoxins as well as binary, ternary, and quaternary mixtures. Finally, a smartphone app interface has been developed for rapid on-site data processing and result display. DA - 2019/8/20/ PY - 2019/8/20/ DO - 10.1021/acs.analchem.9b00750 VL - 91 IS - 16 SP - 10448-10457 SN - 1520-6882 UR - https://doi.org/10.1021/acs.analchem.9b00750 ER - TY - JOUR TI - Materials tactile logic via innervated soft thermochromic elastomers AU - Jin, Yang AU - Lin, Yiliang AU - Kiani, Abolfazl AU - Joshipura, Ishan D. AU - Ge, Mingqiao AU - Dickey, Michael D. T2 - Nature Communications AB - Abstract Conventional machines rely on rigid, centralized electronic components to make decisions, which limits complexity and scaling. Here, we show that decision making can be realized on the material-level without relying on semiconductor-based logic. Inspired by the distributed decision making that exists in the arms of an octopus, we present a completely soft, stretchable silicone composite doped with thermochromic pigments and innervated with liquid metal. The ability to deform the liquid metal couples geometric changes to Joule heating, thus enabling tunable thermo-mechanochromic sensing of touch and strain. In more complex circuits, deformation of the metal can redistribute electrical energy to distal portions of the network in a way that converts analog tactile ‘inputs’ into digital colorimetric ‘outputs’. Using the material itself as the active player in the decision making process offers possibilities for creating entirely soft devices that respond locally to environmental interactions or act as embedded sensors for feedback loops. DA - 2019/9/13/ PY - 2019/9/13/ DO - 10.1038/s41467-019-12161-1 UR - https://doi.org/10.1038/s41467-019-12161-1 ER - TY - JOUR TI - The Acidaminococcus sp. Cas12a nuclease recognizes GTTV and GCTV as non-canonical PAMs AU - Jacobsen, Thomas AU - Liao, Chunyu AU - Beisel, Chase L. T2 - FEMS MICROBIOLOGY LETTERS AB - The clustered regularly interspaced short palindromic repeat (CRISPR)-associated (Cas) nuclease Acidaminococcus sp. Cas12a (AsCas12a, also known as AsCpf1) has become a popular alternative to Cas9 for genome editing and other applications. AsCas12a has been associated with a TTTV protospacer-adjacent motif (PAM) as part of target recognition. Using a cell-free transcription-translation (TXTL)-based PAM screen, we discovered that AsCas12a can also recognize GTTV and, to a lesser degree, GCTV motifs. Validation experiments involving DNA cleavage in TXTL, plasmid clearance in Escherichia coli, and indel formation in mammalian cells showed that AsCas12a was able to recognize these motifs, with the GTTV motif resulting in higher cleavage efficiency compared to the GCTV motif. We also observed that the -5 position influenced the activity of DNA cleavage in TXTL and in E. coli, with a C at this position resulting in the lowest activity. Together, these results show that wild-type AsCas12a can recognize non-canonical GTTV and GCTV motifs and exemplify why the range of PAMs recognized by Cas nucleases are poorly captured with a consensus sequence. DA - 2019/4// PY - 2019/4// DO - 10.1093/femsle/fnz085 VL - 366 IS - 8 SP - SN - 1574-6968 KW - Cas nuclease KW - Cpf1 KW - CRISPR-Cas systems KW - PAM KW - TIDE KW - TXTL ER - TY - JOUR TI - AgNP/crystalline PANI/EBP-composite-based supercapacitor electrode with internal chemical interactions AU - Kim, Hyungjoo AU - Ramalingam, Manivannan AU - Balakumar, Vellaichamy AU - Zhang, Xiangwu AU - Gao, Wei AU - Son, Young-A AU - Bradford, Philip D. T2 - JOURNAL OF APPLIED POLYMER SCIENCE AB - ABSTRACT In this article, polyaniline (PANI) was conformally coated on epoxide‐functionalized buckypaper (EBP). Because of the presence of epoxide functional groups, chemical interactions occurred between oxygen in the epoxide groups and NH in the PANI. These chemical interactions were identified by peak shifts and intensity changes in Raman spectra. Additionally, crystalline peaks were clearly observed through X‐ray diffraction. However, Raman peak changes or crystalline peaks were not observed in nonfunctionalized buckypaper (purified pristine buckypaper [PPBP])‐based composites. Both hydrogen bonding and crystalline nature of EBP‐PANI enhanced its electrical conductivity, producing a specific capacitance better than that of PPBP‐PANI. Finally, Ag nanoparticles (AgNPs) were applied to EBP‐PANI to further enhance its electrical conductivity. Owing to the presence of AgNPs and their interactions with the N in PANI, the specific capacitance of EBP‐PANI‐AgNP reached 915.62 F/g. These results emphasize the positive effect of chemical interactions and crystalline nature of EBP‐based composites on their electrochemical performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48164. DA - 2019/11/20/ PY - 2019/11/20/ DO - 10.1002/app.48164 VL - 136 IS - 44 SP - SN - 1097-4628 UR - https://publons.com/publon/26924632/ ER - TY - JOUR TI - Incorporation of an ionic liquid into a midblock-sulfonated multiblock polymer for CO2 capture AU - Dai, Zhongde AU - Ansaloni, Luca AU - Ryan, Justin J. AU - Spontak, Richard J. AU - Deng, Liyuan T2 - JOURNAL OF MEMBRANE SCIENCE AB - In the present work, hybrid block ionomer/ionic liquid (IL) membranes containing up to 40 wt% IL are prepared by incorporating 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) into a midblock-sulfonated pentablock polymer (Nexar) that behaves as a thermoplastic elastomer. Various analytical techniques, including thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, small-angle X-ray scattering (SAXS), and water sorption have been employed to characterize the resultant membrane materials. Single- and mixed-gas permeation tests have been performed at different relative humidity conditions to evaluate membrane gas-separation performance and interrogate the molecular transport of CO2 through these membranes. Addition of IL to Nexar systematically enhances CO2 permeability through membranes in the dry state. Introduction of water vapor into the gas feed further promotes CO2 transport, yielding a maximum permeability of 194 Barrers and a maximum CO2/N2 selectivity of 128 under different test conditions. These results confirm that humidified Nexar/IL hybrid membranes constitute promising candidates for the selective removal, and subsequent capture, of CO2 from mixed gas streams to reduce the environmental contamination largely responsible for global climate change. DA - 2019/10/15/ PY - 2019/10/15/ DO - 10.1016/j.memsci.2019.117193 VL - 588 SP - SN - 1873-3123 KW - Sulfonated block polymer KW - Ionic liquids KW - Hybrid membranes KW - CO2 separation ER - TY - JOUR TI - Flexible polyaniline-carbon nanofiber supercapacitor electrodes AU - Yanilmaz, Meltem AU - Dirican, Mahmut AU - Asiri, Abdullah M. AU - Zhang, Xiangwu T2 - JOURNAL OF ENERGY STORAGE AB - Flexible polyaniline-carbon nanofiber (PANI-CNF) composites were fabricated and evaluated for use as supercapacitor electrodes. Sol-gel and electrospinning techniques were employed to produce flexible carbon nanofibers and polyaniline coating was applied via in-situ chemical polymerization to further improve the electrochemical properties of the electrodes. The performance of flexible PANI-CNF electrodes was investigated in symmetric supercapacitor cells. Results showed that binder-free flexible PANI-CNF electrodes had high capacitance of 234 F/g and excellent cycling stability with capacitance retention of about 90% after 1000 cycles. Ragone plots were also presented and a high energy density of 32 Wh/kg at the power density of 500 W/kg was achieved for the flexible PANI-CNF electrode prepared with 12 h polymerization. In addition, mechanical tests demonstrated that free-standing PANI-CNF electrodes were durable and highly flexible. Therefore, combining sol-gel and electrospinning techniques is a facile and effective way to achieve flexible carbon nanofiber electrodes and this work provides a new approach for designing flexible electrodes with exceptional electrochemical performance, which is very promising for practical application in the energy storage field. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.est.2019.100766 VL - 24 SP - SN - 2352-152X UR - https://publons.com/publon/22573151/ KW - Carbon nanofiber KW - Polyaniline KW - Composite KW - Electrode ER - TY - JOUR TI - Tailoring the Chemical Modification of Chitosan Hydrogels to Fine-Tune the Release of a Synergistic Combination of Chemotherapeutics AU - Schneible, John D. AU - Singhal, Ankush AU - Lilova, Radina L. AU - Hall, Carol K. AU - Grafmueller, Andrea AU - Menegatti, Stefano T2 - BIOMACROMOLECULES AB - Combination chemotherapy with a defined ratio and sequence of drug release is a clinically established and effective route to treat advanced solid tumors. In this context, a growing body of literature demonstrates the potential of hydrogels constructed with chemically modified polysaccharides as depots for controlled release of chemotherapeutics. Identifying the appropriate modification in terms of physicochemical properties of the functional group and its degree of substitution (χ) to achieve the desired release profile for multiple drugs is, however, a complex multivariate problem. To address this issue, we have developed a computational toolbox that models the migration of a drug pair through a hydrated network of polysaccharide chains modified with hydrophobic moieties. In this study, we chose doxorubicin (DOX) and Gemcitabine (GEM) as model drugs, as their synergistic effect against breast cancer has been thoroughly investigated, and chitosan as the model polymer. Our model describes how the modification of chitosan chains with acetyl, butanoyl, and heptanoyl moieties at different values χ governs both the structure of the hydrogel network and drug migration through it. Our experimental data confirm the in silico predictions for both single- and dual-drug release and, most notably, the counterintuitive inversion of release vs χ that occurs when switching from a single- to a dual-drug system. Consensus between predicted and experimental data indicates that acetyl modifications (χ = 32-42%) and butanoyl modifications (χ = 19-24%) provide synergistic GEM/DOX release molar ratios (i.e., 5-10). Collectively, these results demonstrate the potential of this model in guiding the design of chemotherapeutic hydrogels to combat cancer. DA - 2019/8// PY - 2019/8// DO - 10.1021/acs.biomac.9b00707 VL - 20 IS - 8 SP - 3126-3141 SN - 1526-4602 ER - TY - JOUR TI - Molecular simulation of polymers with a SAFT-gamma Mie approach AU - Pervaje, Amulya K. AU - Walker, Christopher C. AU - Santiso, Erik E. T2 - MOLECULAR SIMULATION AB - We review the group contribution Statistical Associating Fluid Theory with Mie interaction potentials (SAFT-γ Mie) approach for building coarse-grained models for molecular simulation of polymeric systems. In this top-down method, force field parameters for coarse-grained polymer models can be derived from thermodynamic information on constituent monomer units using the SAFT-γ Mie equation of state (EoS). This strategy can facilitate high-throughput computational screening of polymeric materials, with a corresponding states correlation expediting the force field fitting. Accurate and transferable non-bonded parameters linked to macroscopic thermodynamic data allow for calculation of properties beyond those obtainable from the EoS alone. To overcome limitations of SAFT-γ Mie regarding polymer chain stiffness and branching, hybrid top-down/bottom-up approaches have combined non-bonded parameters from SAFT-γ Mie with bond-stretching and angle-bending potentials from higher-resolution force fields. Our review critically evaluates the performance of recent SAFT-γ Mie polymer models, highlighting the strengths and weaknesses in the context of other equation of state and coarse-graining methods. DA - 2019/10/13/ PY - 2019/10/13/ DO - 10.1080/08927022.2019.1645331 VL - 45 IS - 14-15 SP - 1223-1241 SN - 1029-0435 KW - Polymers KW - molecular dynamics KW - SAFT-gamma Mie KW - equations of state KW - force fields ER - TY - JOUR TI - Characterising the throat diameter of through-pores in network structures using a percolation criterion AU - Wang, Kye Won AU - Hall, Carol K. T2 - MOLECULAR PHYSICS AB - We present a method for measuring the pore throat diameter of a simulated porous material. The pore throat diameter is the size of the narrowest pore that has both an entrance and an exit in a network structure. Knowledge of the pore throat diameter allows estimation of the size of the largest molecules that can travel through a network structure without interruption. In this method, a chain of virtual circles (in 2-dimensions) or spheres (in 3-dimensions) is constructed along a percolated path through the pores in a network. The diameter of the largest circle or sphere for which this is possible is the pore throat diameter. The method is applied to two 2-dimensional models (one where we know the pore throat diameter and one where we do not), and well predicts the pore throat diameters in each case. The pore throat diameter of a 3-dimensional DNA-mediated hydrogel model is also determined. This method is applicable to any porous structure for which molecular coordinate information is available. The ability to predict pore throat diameters in simulation could be useful for determining the size of molecules that can safely be administered by hydrogel drug delivery systems. DA - 2019/// PY - 2019/// DO - 10.1080/00268976.2019.1654140 VL - 117 IS - 23-24 SP - 3614-3622 SN - 1362-3028 KW - Pore throat KW - percolation KW - computation KW - porous materials ER - TY - JOUR TI - Mixed iron-manganese oxides as redox catalysts for chemical looping-oxidative dehydrogenation of ethane with tailorable heat of reactions AU - Yusuf, Seif AU - Haribal, Vasudev AU - Jackson, Daniel AU - Neal, Luke AU - Li, Fanxing T2 - APPLIED CATALYSIS B-ENVIRONMENTAL AB - The chemical looping-oxidative dehydrogenation (CL-ODH) of ethane is investigated in this study. In CL-ODH, a redox catalyst donates its lattice oxygen to combust hydrogen formed from ethane dehydrogenation (ODH reactor). The reduced redox catalyst is then transferred to a separate reactor (regenerator), where it is re-oxidized with air. Typically, the ODH step is endothermic, due to the high endothermicity to reduce the redox catalyst. This energy demand is met through sensible heat carried by the redox catalyst from the regenerator, which operates at a higher temperature. This temperature difference between the two reactors leads to exergy losses. We report an Fe-Mn redox catalyst showing tunable exothermic heat of reduction. Promotion with Na2WO4 resulted in high ethylene yields due to the suppression of surface Fe/Mn. ASPEN Plus® simulations indicated that Fe-Mn redox catalysts can lower the temperature difference between the two reactors. This can lead to efficiency improvements for CL-ODH. DA - 2019/11/15/ PY - 2019/11/15/ DO - 10.1016/j.apcatb.2019.117885 VL - 257 SP - SN - 1873-3883 UR - https://doi.org/10.1016/j.apcatb.2019.117885 KW - Oxidative dehydrogenation KW - Chemical looping KW - Ethane KW - Ethylene ER - TY - JOUR TI - Role of continuous flow processes in green manufacturing of pharmaceuticals and specialty chemicals AU - Bennett, Jeffrey A AU - Campbell, Zachary S AU - Abolhasani, Milad T2 - Current Opinion in Chemical Engineering AB - Recently, focus has turned towards increasing chemical process safety and sustainability for fundamental and applied research as well as manufacturing of pharmaceuticals and specialty chemicals. Flow chemistry techniques have attracted significant interest as a way to implement and improve chemical processes in order to satisfy the growing demand for chemical sustainability. In this article, we discuss emerging flow chemistry technologies with applications in green manufacturing of high-value chemicals and efficient screening of chemical reaction space. Continuous manufacturing techniques are increasingly being utilized to reduce the amount of material and energy utilized in a process while incorporating real-time analysis, control, and enhanced process safety. Beyond continuous production, flow screening techniques can rapidly search a multi-dimensional reaction space to improve process design, performance, and efficiency. Furthermore, time-efficient and material-efficient (green) flow screening platforms can be utilized to develop the next generation of process development technologies including predictive reaction models and process scale-up strategies. DA - 2019/12// PY - 2019/12// DO - 10.1016/j.coche.2019.07.007 VL - 26 SP - 9-19 UR - https://doi.org/10.1016/j.coche.2019.07.007 ER - TY - JOUR TI - Ultrastretchable Elastic Shape Memory Fibers with Electrical Conductivity AU - Park, Sungjune AU - Baugh, Neil AU - Shah, Hardil K. AU - Parekh, Dishit P. AU - Joshipura, Ishan D. AU - Dickey, Michael D. T2 - Advanced Science AB - Herein, elastomeric fibers that have shape memory properties due to the presence of a gallium core that can undergo phase transition from solid to liquid in response to mild heating are described. The gallium is injected into the core of a hollow fiber formed by melt processing. This approach provides a straightforward method to create shape memory properties from any hollow elastic fiber. Solidifying the core changes the effective fiber modulus from 4 to 1253 MPa. This increase in stiffness can preserve the fiber in a deformed shape. The elastic energy stored in the polymer shell during deformation drives the fiber to relax back to its original geometry upon melting the solid gallium core, allowing for shape memory. Although waxes are used previously for this purpose, the use of gallium is compelling because of its metallic electrical and thermal conductivity. In addition, the use of a rigid metallic core provides perfect fixity of the shape memory fiber. Notably, the use of gallium-with a melting point above room temperature but below body temperature-allows the user to melt and deform local regions of the fiber by hand and thereby tune the effective modulus and shape of the fiber. DA - 2019/11// PY - 2019/11// DO - 10.1002/advs.201901579 UR - https://doi.org/10.1002/advs.201901579 KW - elastic shape memory fibers KW - liquid metals KW - stretchable electronics ER - TY - JOUR TI - Interfacial Rheology of Gallium-Based Liquid Metals AU - Jacob, Alan R. AU - Parekh, Dishit P. AU - Dickey, Michael D. AU - Hsiao, Lilian C. T2 - Langmuir AB - Gallium and its alloys react with oxygen to form a native oxide that encapsulates the liquid metal with a solid “skin”. The viscoelasticity of this skin is leveraged in applications such as soft electronics, 3D printing, and components for microfluidic devices. In these applications, rheological characterization of the oxide skin is paramount for understanding and controlling liquid metals. Here, we provide a direct comparison of the viscoelastic properties for gallium-based liquid metals and illustrate the effect of different subphases and addition of a dopant on the elastic nature of the oxide skin. The du Noüy ring method is used to investigate the interfacial rheology of oxide skins formed by gallium-based liquid metal alloys. The results show that the oxide layer on gallium, eutectic gallium–indium, and Galinstan are viscoelastic with a yield stress. Furthermore, the storage modulus of the oxide layer is affected by exposure to water or when small amounts of aluminum dopant are added to the liquid metals. The former scenario decreases the interfacial storage modulus of the gallium by 35–85% while the latter increases the interfacial storage modulus by 25–45%. The presence of water also changes the chemical composition of the oxide skin. Scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy suggest that a microstructural evolution of the interface occurs when aluminum preferentially migrates from the bulk to the surface. These studies provide guidance on selecting liquid metals as well as simple methods to optimize their rheological behavior for future applications. DA - 2019/8/13/ PY - 2019/8/13/ DO - 10.1021/acs.langmuir.9b01821 VL - 35 IS - 36 SP - 11774-11783 J2 - Langmuir LA - en OP - SN - 0743-7463 1520-5827 UR - http://dx.doi.org/10.1021/acs.langmuir.9b01821 DB - Crossref ER - TY - JOUR TI - Thermomechanical and Free-Volume Properties of Polyester–Polyol Films for Coatings Applications: Role of Diol Composition AU - Tilly, Joseph C. AU - Pervaje, Amulya K. AU - Inglefield, David L., Jr. AU - Detwiler, Andrew T. AU - Santiso, Erik E. AU - Khan, Saad A. AU - Spontak, Richard J. T2 - ACS Applied Polymer Materials AB - Because of their utility in diverse coatings applications, a model series of polyester–polyol films possessing different diol formulations and cross-linked with an aliphatic isocyanate cross-linker under two different conditions is systematically investigated to elucidate the effects of backbone chemistry and cure temperature on the ultimate thermomechanical and free-volume properties. The diol of particular interest in this study is 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD). The glass transition temperature of the films, as measured by thermal calorimetry and dynamic mechanical analysis, is observed to correlate strongly with TMCD content. In the limit of 100 wt % TMCD diol, the operable temperature range for these films increases by as much as ∼60 °C. Surface mechanical properties, interrogated by nanoindentation, also depend sensitively on both TMCD content and cure conditions, and a previously reported phenomenon known as “pileup” is considered to explain some of our observations. Results from positron annihilation lifetime spectroscopy indicate that the nanoscopic free volume of films containing varying levels of TMCD is strongly dependent on chemical makeup but not on cure conditions. DA - 2019/9/13/ PY - 2019/9/13/ DO - 10.1021/acsapm.9b00502 VL - 1 IS - 9 SP - 2398-2406 UR - https://doi.org/10.1021/acsapm.9b00502 KW - polyester-polyol KW - transparent coating KW - thermoset KW - thermal cure KW - PALS ER - TY - JOUR TI - Validation and Application of a Kinetic Model for Downdraft Biomass Gasification Simulation AU - Smith, Joseph D. AU - Alembath, Anand AU - Al-Rubaye, Haider AU - Yu, Jia AU - Gao, , Xi AU - Golpour, Hassan T2 - CHEMICAL ENGINEERING & TECHNOLOGY AB - Abstract Biomass gasification is widely recognized as an effective method to obtain renewable energy. To accurately predict the syngas and tar compositions is a challenge. A chemical reaction kinetics model based on comprehensive gasification kinetics is proposed to simulate downdraft biomass gasification. The kinetic model is validated by direct comparison to experimental results of two downdraft gasifiers available in the literature and is found to be more accurate than the widely used Gibbs energy‐minimizing model (GEM model). The kinetic model is then applied to investigate the effects of equivalence ratio (ER), gasification temperature, biomass moisture content, and biomass composition on syngas and tar production. Accurate water‐gas shift and CO shift reaction kinetics are found critical to achieve good agreement with experimental results. DA - 2019/12// PY - 2019/12// DO - 10.1002/ceat.201900304 VL - 42 IS - 12 SP - 2505-2519 SN - 1521-4125 KW - Biomass gasification KW - Downdraft gasifier KW - Gasification KW - Reaction kinetics ER - TY - JOUR TI - Molecular theory of a ferromagnetic nematic liquid crystal AU - Geier, Immanuel S. AU - Wandrei, Stefanie M. AU - Skutnik, Robert A. AU - Schoen, Martin T2 - PHYSICAL REVIEW E AB - We employ a version of classical density functional theory to study the phase behavior of a simple model liquid crystal in an external field. The uniaxially symmetric molecules have a spherically symmetric core with superimposed orientation-dependent attractions. The interaction between the cores consists of a hard-sphere repulsion plus an isotropic square-well attraction. The anisotropic part of the interaction potential allows for the formation of a uniaxially symmetric nematic phase. The orientation of the molecules couples to an external polar field. The external field is capable of rotating the nematic director $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{\mathbit{n}}$ in the $x\ensuremath{-}z$ plane. The field is also capable of changing the topology of the phase diagram in that it suppresses the phase coexistence between an isotropic liquid and a nematic phase observed in the absence of the field. We study the transition from an unpolar to a polar nematic phase in terms of the orientation-distribution function (odf), nematic and polar order parameters, and components of $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{\mathbit{n}}$. If represented suitably the odf allows us to study orientational changes during the switching process between nonpolar and polar nematic phases. We also give a simple argument that explains why nematic order is lost whereas polar order persists up to the gas-liquid critical point along the coexistence curve. We also discuss the relevance of our theory for future experimental studies. DA - 2019/8/13/ PY - 2019/8/13/ DO - 10.1103/PhysRevE.100.022702 VL - 100 IS - 2 SP - SN - 2470-0053 ER - TY - JOUR TI - Quantitative fermentation of unpretreated transgenic poplar by Caldicellulosiruptor bescii AU - Straub, Christopher T. AU - Khatibi, Piyum A. AU - Wang, Jack P. AU - Conway, Jonathan M. AU - Williams-Rhaesa, Amanda M. AU - Peszlen, Ilona M. AU - Chiang, Vincent L. AU - Adams, Michael W. W. AU - Kelly, Robert M. T2 - NATURE COMMUNICATIONS AB - Abstract Microbial fermentation of lignocellulosic biomass to produce industrial chemicals is exacerbated by the recalcitrant network of lignin, cellulose and hemicelluloses comprising the plant secondary cell wall. In this study, we show that transgenic poplar ( Populus trichocarpa ) lines can be solubilized without any pretreatment by the extreme thermophile Caldicellulosiruptor bescii that has been metabolically engineered to shift its fermentation products away from inhibitory organic acids to ethanol. Carbohydrate solubilization and conversion of unpretreated milled biomass is nearly 90% for two transgenic lines, compared to only 25% for wild-type poplar. Unexpectedly, unpretreated intact poplar stems achieved nearly 70% of the fermentation production observed with milled poplar as the substrate. The nearly quantitative microbial conversion of the carbohydrate content of unpretreated transgenic lignocellulosic biomass bodes well for full utilization of renewable biomass feedstocks. DA - 2019/8/7/ PY - 2019/8/7/ DO - 10.1038/s41467-019-11376-6 VL - 10 SP - SN - 2041-1723 ER - TY - JOUR TI - Computer Simulation of Surface-Initiated Controlled Radical Polymerization: Effect of Free-Monomer Model on Brush Properties AU - Turgman-Cohen, Salomon AU - Geezer, Jan T2 - MACROMOLECULAR THEORY AND SIMULATIONS AB - Abstract Monte Carlo simulation is employed using the bond‐fluctuation model (BFM) to explore the role of free‐monomer model on surface‐initiated controlled polymerization from flat substrates. Three free‐monomer models differ in two aspects: 1) their extent of excluded volume interactions between free‐monomer/polymer segments and 2) monomer availability (finite or infinite) during the simulation. In the explicit monomer (EM) model, free‐monomers behave as a single BFM‑type units. In the phantom monomer (PM) model, free‐monomers act analogously to those in the EM model but lack excluded volume interactions with the growing polymers. In the implicit monomer (IM) model, no explicit monomers are included in the simulation box; the polymers can grow as long as space is available near active chain‐ends. It is found that the breadth of the molecular weight distribution of the grown polymers decreases from EM, to PM, to IM models. With the EM model, free‐monomers are excluded from the near‐surface region, while with the PM model they are not. Due to its excluded volume interactions, the EM model tends to compress the brush against the substrate. Finally, the relaxation of the shape of a polydisperse brush after the polymerization reaction ends has been reported. DA - 2019/9// PY - 2019/9// DO - 10.1002/mats.201900033 VL - 28 IS - 5 SP - SN - 1521-3919 KW - controlled radical polymerization KW - Monte Carlo KW - polymer brushes KW - simulation KW - tethered polymers ER - TY - JOUR TI - Lignocellulose solubilization and conversion by extremely thermophilic Caldicellulosiruptor bescii improves by maintaining metabolic activity AU - Straub, Christopher T. AU - Khatibi, Piyum A. AU - Otten, Jonathan K. AU - Adams, Michael W. W. AU - Kelly, Robert M. T2 - BIOTECHNOLOGY AND BIOENGINEERING AB - The extreme thermophile Caldicellulosiruptor bescii solubilizes and metabolizes the carbohydrate content of lignocellulose, a process that ultimately ceases because of biomass recalcitrance, accumulation of fermentation products, inhibition by lignin moieties, and reduction of metabolic activity. Deconstruction of low loadings of lignocellulose (5 g/L), either natural or transgenic, whether unpretreated or subjected to hydrothermal processing, by C. bescii typically results in less than 40% carbohydrate solubilization. Mild alkali pretreatment (up to 0.09 g NaOH/g biomass) improved switchgrass carbohydrate solubilization by C. bescii to over 70% compared to less than 30% for no pretreatment, with two-thirds of the carbohydrate content in the treated switchgrass converted to acetate and lactate. C. bescii grown on high loadings of unpretreated switchgrass (50 g/L) retained in a pH-controlled bioreactor slowly purged (τ = 80 hr) with growth media without a carbon source improved carbohydrate solubilization to over 40% compared to batch culture at 29%. But more significant was the doubling of solubilized carbohydrate conversion to fermentation products, which increased from 40% in batch to over 80% in the purged system, an improvement attributed to maintaining the bioreactor culture in a metabolically active state. This strategy should be considered for optimizing solubilization and conversion of lignocellulose by C. bescii and other lignocellulolytic microorganisms. DA - 2019/8// PY - 2019/8// DO - 10.1002/bit.26993 VL - 116 IS - 8 SP - 1901-1908 SN - 1097-0290 KW - biofuels KW - bioreactor KW - Caldicellulosiruptor bescii KW - lignocellulose KW - switchgrass ER - TY - JOUR TI - Multifunctional High-Performance Electrocatalytic Properties of Nb2O5 Incorporated Carbon Nanofibers as Pt Support Catalyst AU - Shanmugapriya, Sathyanarayanan AU - Zhu, Pei AU - Yan, Chaoyi AU - Asiri, Abdullah M. AU - Zhang, Xiangwu AU - Selvan, Ramakrishnan Kalai T2 - ADVANCED MATERIALS INTERFACES AB - Abstract Designing an electrocatalyst by integrating multiple classes of materials is an effective strategy for reinforcing the electrode properties. This study demonstrates a facile electrospinning technique for functionalizing the carbon nanofibers (CNFs) with Nb 2 O 5 co‐catalyst as the support material for platinum nanoparticles. The resultant Nb CNF‐Pt electrode has a sensible Pt loading of 30 µg cm −2 and manifests high catalytic activity towards the oxygen reduction reaction (ORR), methanol oxidation reaction (MOR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). The Nb CNF‐Pt outperforms the commercial 20 wt% Pt loaded carbon with high positive onset potential (0.99 V vs reversible hydrogen electrode (RHE)) and half‐wave potential (0.87 V vs RHE) during ORR. It also provides large electrochemical active surface area (94.19 m 2 g −1 ) and mass activity (783.34 mA mg −1 ) during MOR. Furthermore, the Nb CNF‐Pt electrode demands an extremely minimal overpotential of 37 and 325 mV and a Tafel slope of 38 and 81 mV dec −1 for HER and OER, respectively. The enhanced electrocatalytic activity of Nb CNF‐Pt is attributed to the strong metal–support interaction between Nb 2 O 5 and Pt, resulting in a uniform loading of Pt NPs with reduced particle size and agglomeration‐free distribution. DA - 2019/9/6/ PY - 2019/9/6/ DO - 10.1002/admi.201900565 VL - 6 IS - 17 SP - SN - 2196-7350 UR - https://publons.com/publon/22082964/ KW - carbon nanofibers KW - co-catalysts KW - niobium oxide KW - Pt catalyst supports ER - TY - JOUR TI - Determinants of sulphur chemolithoautotrophy in the extremely thermoacidophilic Sulfolobales AU - Zeldes, Benjamin M. AU - Loder, Andrew J. AU - Counts, James A. AU - Haque, Mashkurul AU - Widney, Karl A. AU - Keller, Lisa M. AU - Albers, Sonja-Verena AU - Kelly, Robert M. T2 - ENVIRONMENTAL MICROBIOLOGY AB - Summary Species in the archaeal order Sulfolobales thrive in hot acid and exhibit remarkable metabolic diversity. Some species are chemolithoautotrophic, obtaining energy through the oxidation of inorganic substrates, sulphur in particular, and acquiring carbon through the 3‐hydroxypropionate/4‐hydroxybutyrate (3‐HP/4‐HB) CO 2 ‐fixation cycle. The current model for sulphur oxidation in the Sulfolobales is based on the biochemical analysis of specific proteins from Acidianus ambivalens , including sulphur oxygenase reductase (SOR) that disproportionates S° into H 2 S and sulphite (SO 3 2− ). Initial studies indicated SOR catalyses the essential first step in oxidation of elemental sulphur, but an ancillary role for SOR as a ‘recycle’ enzyme has also been proposed. Here, heterologous expression of both SOR and membrane‐bound thiosulphate‐quinone oxidoreductase (TQO) from Sulfolobus tokodaii ‘restored’ sulphur oxidation capacity in Sulfolobus acidocaldarius DSM639, but not autotrophy, although earlier reports indicate this strain was once capable of chemolithoautotrophy. Comparative transcriptomic analyses of Acidianus brierleyi , a chemolithoautotrophic sulphur oxidizer, and S. acidocaldarius DSM639 showed that while both share a strong transcriptional response to elemental sulphur, S. acidocaldarius DSM639 failed to upregulate key 3‐HP/4‐HB cycle genes used by A. brierleyi to drive chemolithoautotrophy. Thus, the inability for S. acidocaldarius DSM639 to grow chemolithoautotrophically may be rooted more in gene regulation than the biochemical capacity. DA - 2019/10// PY - 2019/10// DO - 10.1111/1462-2920.14712 VL - 21 IS - 10 SP - 3696-3710 SN - 1462-2920 ER - TY - JOUR TI - Air, Water Vapor, and Aerosol Transport through Textiles with Surface Functional Coatings of Metal Oxides and Metal-Organic Frameworks AU - Pomerantz, Natalie L. AU - Anderson, Erin E. AU - Dugan, Nicholas P. AU - Hoffman, Nicole F. AU - Barton, Heather F. AU - Lee, Dennis T. AU - Oldham, Christopher J. AU - Peterson, Gregory W. AU - Parsons, Gregory N. T2 - ACS APPLIED MATERIALS & INTERFACES AB - Currently, air permeable chemical/biological (CB) protective garments are based on activated carbon technology, which reduces moisture vapor transport needed for evaporative cooling and has potential to absorb and concentrate toxic materials. Researchers are exploring classes of sorbent materials that can selectively accumulate and decompose target compounds for potential to enhance protective suits and allow for novel filtration devices. Here, the metal–organic frameworks (MOFs) UiO-66-NH2 and HKUST-1 have been identified as such materials. To better understand how MOFs can perform in future CB protective systems, atomic layer deposition (ALD) and solution deposition were used to modify nonwoven polypropylene and flame-resistant fabrics with HKUST-1 and UiO-66-NH2. Air permeation, water vapor transport, filtration efficiency, and chemical reactivity against chemical agent simulants were assessed in relation to ALD thickness and MOF crystal size. MOF deposition on substrates decreased both air and chemical permeation while increasing filtration efficiency and chemical sorption. Moisture vapor transport was not affected by MOF growth on substrates, which is promising when considering thermal properties of protective garments. Future work should continue to explore how MOF deposition onto fiber and textile substrates impacts transport properties and chemical absorbance. DA - 2019/7/10/ PY - 2019/7/10/ DO - 10.1021/acsami.9b04091 VL - 11 IS - 27 SP - 24683-24690 SN - 1944-8252 UR - https://doi.org/10.1021/acsami.9b04091 KW - atomic layer deposition KW - metal-organic frameworks KW - aerosol transport KW - filtration KW - chemical/biological protection KW - breathable materials ER - TY - JOUR TI - Influence of surface topography attributes on settlement and adhesion of natural and synthetic species AU - Erramilli, Shreya AU - Genzer, Jan T2 - SOFT MATTER AB - Surface topographies of various sizes, shapes, and spatial organization abound in nature. DA - 2019/5/28/ PY - 2019/5/28/ DO - 10.1039/c9sm00527g VL - 15 IS - 20 SP - 4045-4067 SN - 1744-6848 ER - TY - JOUR TI - The engineering principles of combining a transcriptional incoherent feedforward loop with negative feedback AU - Reeves, Gregory T. T2 - JOURNAL OF BIOLOGICAL ENGINEERING AB - Regulation of gene expression is of paramount importance in all living systems. In the past two decades, it has been discovered that certain motifs, such as the feedforward motif, are overrepresented in gene regulatory circuits. Feedforward loops are also ubiquitous in process control engineering, and are nearly always structured so that one branch has the opposite effect of the other, which is a structure known as an "incoherent" feedforward loop in biology. In engineered systems, feedforward control loops are subject to several engineering constraints, including that (1) they are finely-tuned so that the system returns to the original steady state after a disturbance occurs (perfect adaptation), (2) they are typically only implemented in the combination with negative feedback, and (3) they can greatly improve the stability and dynamical characteristics of the conjoined negative feedback loop. On the other hand, in biology, incoherent feedforward loops can serve many purposes, one of which may be perfect adaptation. It is an open question as to whether those that achieve perfect adaptation are subject to the above engineering principles.We analyzed an incoherent feedforward gene regulatory motif from the standpoint of the above engineering principles. In particular, we showed that an incoherent feedforward loop Type 1 (I1-FFL), from within a gene regulatory circuit, can be finely-tuned for perfect adaptation after a stimulus, and that the robustness of this behavior is increased by the presence of moderate negative feedback. In addition, we analyzed the advantages of adding a feedforward loop to a system that already operated under negative feedback, and found that the dynamical properties of the combined feedforward/feedback system were superior.Our analysis shows that many of the engineering principles used in engineering design of feedforward control are also applicable to feedforward loops in biological systems. We speculate that principles found in other domains of engineering may also be applicable to analogous structures in biology. DA - 2019/7/10/ PY - 2019/7/10/ DO - 10.1186/s13036-019-0190-3 VL - 13 SP - SN - 1754-1611 KW - Incoherent feedforward loop KW - Negative feedback KW - Gene regulation KW - Network motif KW - Engineering principles ER - TY - JOUR TI - Corrosion resistant coating based on thiol-ene polymeric system AU - Rezaei, Farzad AU - Dickey, Michael D. AU - Hauser, Peter J. T2 - PROGRESS IN ORGANIC COATINGS AB - This study presents a method of preparation of corrosion resistant thin organic coatings. This thin organic coating is designed to protect a stack of several thin inorganic (metallic and oxide) layers that have low infrared emissivity and are sputter deposited on top of a flexible polyethylene terephthalate (PET) substrate. It is argued that, in contact with an acidic environment, the most sensitive material in this stack is indium tin oxide. The proposed protective organic coating consists of a crosslinkable thiol-ene network, a low surface energy fluorinated compound and a silane adhesion promoter cured under exposure to an ultra-violet light source. The results show that such the optimized organic precursor can lead to thin polymeric coating that can successfully protect the sensitive substrate yet does not have a detrimental interference with its low emissivity. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.porgcoat.2019.04.073 VL - 133 SP - 350-356 SN - 0300-9440 KW - Organic coating KW - Acid corrosion KW - ITO KW - Emissivity KW - XRD ER - TY - JOUR TI - Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future AU - Barnes, Paul W. AU - Williamson, Craig E. AU - Lucas, Robyn M. AU - Robinson, Sharon A. AU - Madronich, Sasha AU - Paul, Nigel D. AU - Bornman, Janet F. AU - Bais, Alkiviadis F. AU - Sulzberger, Barbara AU - Wilson, Stephen R. AU - Andrady, Anthony L. AU - McKenzie, Richard L. AU - Neale, Patrick J. AU - Austin, Amy T. AU - Bernhard, Germar H. AU - Solomon, Keith R. AU - Neale, Rachel E. AU - Young, Paul J. AU - Norval, Mary AU - Rhodes, Lesley E. AU - Hylander, Samuel AU - Rose, Kevin C. AU - Longstreth, Janice AU - Aucamp, Pieter J. AU - Ballare, Carlos L. AU - Cory, Rose M. AU - Flint, Stephan D. AU - Gruijl, Frank R. AU - Haeder, Donat-P AU - Heikkila, Anu M. AU - Jansen, Marcel A. K. AU - Pandey, Krishna K. AU - Robson, T. Matthew AU - Sinclair, Craig A. AU - Wangberg, Sten-Ake AU - Worrest, Robert C. AU - Yazar, Seyhan AU - Young, Antony R. AU - Zepp, Richard G. T2 - NATURE SUSTAINABILITY AB - Changes in stratospheric ozone and climate over the past 40-plus years have altered the solar ultraviolet (UV) radiation conditions at the Earth’s surface. Ozone depletion has also contributed to climate change across the Southern Hemisphere. These changes are interacting in complex ways to affect human health, food and water security, and ecosystem services. Many adverse effects of high UV exposure have been avoided thanks to the Montreal Protocol with its Amendments and Adjustments, which have effectively controlled the production and use of ozone-depleting substances. This international treaty has also played an important role in mitigating climate change. Climate change is modifying UV exposure and affecting how people and ecosystems respond to UV; these effects will become more pronounced in the future. The interactions between stratospheric ozone, climate and UV radiation will therefore shift over time; however, the Montreal Protocol will continue to have far-reaching benefits for human well-being and environmental sustainability. Ozone depletion has altered conditions at the Earth’s surface and interacts with climate change. This Review assesses the effects on humans and ecosystems, including implications for food and water security, and the mitigating and ongoing influence of the Montreal Protocol. DA - 2019/7// PY - 2019/7// DO - 10.1038/s41893-019-0314-2 VL - 2 IS - 7 SP - 569-579 SN - 2398-9629 ER - TY - JOUR TI - Insight on the Sequential Vapor Infiltration Mechanisms of Trimethylaluminum with Poly(methyl methacrylate), Poly(vinylpyrrolidone), and Poly(acrylic acid) AU - Hill, Grant T. AU - Lee, Dennis T. AU - Williams, Philip S. AU - Needham, Craig D. AU - Dandley, Erinn C. AU - Oldham, Christopher J. AU - Parsons, Gregory N. T2 - JOURNAL OF PHYSICAL CHEMISTRY C AB - The sequential vapor infiltration (SVI) method, based on atomic layer deposition chemistry, allows the creation of a polymer–inorganic hybrid material through the diffusion of metal–organic vapor reagents into a polymer substrate. This study investigates the reactivity of the ester, amide, and carboxylic acid functional groups of poly(methyl methacrylate) (PMMA), poly(vinylpyrrolidone) (PVP), and poly(acrylic acid) (PAA), respectively, in the presence of trimethylaluminum (TMA) vapor. This work explores the possible reaction mechanisms of these functional groups through in situ Fourier transform infrared spectroscopy and ab initio quantum chemical analysis. At temperatures of ≤100 °C, TMA physisorbs to the carbonyl groups of PMMA. As the temperature is increased, TMA forms a covalent bond with PMMA. TMA physisorbs to PVP and then partially desorbs in the presence of water for all studied temperatures of ≤150 °C. PAA readily reacts with TMA to form a covalent bond with the carbonyl group at 60 °C. This increased reactivity is attributed to the acidic proton in the carboxylic acid moiety based on TMA’s reactivity with hydroxyl-terminated surfaces and ab initio calculations. At temperatures of ≥100 °C, TMA catalyzes anhydride formation in PAA. These insights will help with the prediction of chemical interactions in SVI processes for the development of organic–inorganic hybrid materials. DA - 2019/7/4/ PY - 2019/7/4/ DO - 10.1021/acs.jpcc.9b02153 VL - 123 IS - 26 SP - 16146-16152 SN - 1932-7447 UR - https://doi.org/10.1021/acs.jpcc.9b02153 ER - TY - JOUR TI - Integrated Isothermal Atomic Layer Deposition/Atomic Layer Etching Supercycles for Area-Selective Deposition of TiO2 AU - Song, Seung Keun AU - Saare, Holger AU - Parsons, Gregory N. T2 - CHEMISTRY OF MATERIALS AB - New approaches for area-selective deposition (ASD) are becoming critical for advanced semiconductor patterning. Atomic layer deposition (ALD) and atomic layer etching (ALE), that is, “inverse ALD”, are considered important for ASD, but to date, direct integration of ALD and ALE for ASD has not been reported. This work demonstrates that self-limiting thermally driven ALE, using WF6 and BCl3, can be directly coupled with self-limiting thermal ALD, using TiCl4 and H2O, in a single isothermal reactor at temperature <200 °C to achieve ASD of TiO2 thin films on common Si/SiO2-patterned surfaces without the use of organic nucleation inhibitors. We show that ALD/ALE “supercycles” (where one supercycle comprises, e.g., 30 ALD cycles followed by 5 ALE cycles) can be reliably repeated to yield more than 12 nm of TiO2 while maintaining a selectivity fraction S > 0.9, nearly a 10× improvement over previous reports of inherent TiO2 ASD. After ALD/ALE (=30/5) 14 supercycles at 170 °C, X-ray photoelectron spectroscopy data show a small Ti 2p signal on Si–H (hydrogen fluoride-cleaned Si), with no Ti 2p signal detected after additional “postetch” ALE cycles. At 150 °C, extended supercycles lead to unwanted particles visible by electron microscopy, which is ascribed to the formation of unreactive mixed silicon/titanium oxide nuclei. The number density of visible particles is consistent with modeled film growth trends. Overall, this work provides new insights into the capabilities for ASD of dielectric materials and a starting point to realize more complex atomic-scale processes using ALD, ALE, and other self-limiting reaction schemes. DA - 2019/7/9/ PY - 2019/7/9/ DO - 10.1021/acs.chemmater.9b01143 VL - 31 IS - 13 SP - 4793-4804 SN - 1520-5002 UR - https://doi.org/10.1021/acs.chemmater.9b01143 ER - TY - JOUR TI - Quantification on Growing Mass of Solid Electrolyte Interphase and Deposited Mn(II) on the Silicon Anode of LiMn2O4 Full Lithium-Ion Cells AU - Chen, Haihui AU - Xu, Hanying AU - Zeng, Yingying AU - Ma, Tianyi AU - Wang, Wei AU - Liu, Limin AU - Wang, Fang AU - Zhang, Xiangwu AU - Qiu, Xinping T2 - ACS Applied Materials & Interfaces AB - Silicon is considered to be one of the most important high-energy density anode materials for next-generation lithium-ion batteries. A large number of experimental studies on silicon anode have achieved better results, and greatly promoted its practical application potentiality, but almost of them are only tested in metal lithium half batteries. There is still an unavoidable question for commercial applications: what is the performance of the full cell composed of a silicon anode and a manganese-based material cathode? In this paper, the growing solid electrolyte interphase (SEI) and deposited manganese ions of the silicon anode's surface of the spinel lithium manganese oxide LiMn2O4/silicon full cells are quantitatively studied during electrochemical cycling, and the SEI performances are tested by differential scanning calorimetry to find out the reason for the rapid decline of reversible capacity in the LiMn2O4/silicon system. The experimental results show that manganese ions can make SEI films rapidly grow on the silicon anode and make SEI films more brittle, which results in lower Coulombic efficiency and rapid decline in capacity of the silicon anode. DA - 2019/8/7/ PY - 2019/8/7/ DO - 10.1021/acsami.9b07400 VL - 11 IS - 31 SP - 27839-27845 UR - https://doi.org/10.1021/acsami.9b07400 KW - solid electrolyte interphase KW - quantification KW - Coulombic efficiency KW - lithium ion battery KW - full cell ER - TY - JOUR TI - The thermophilic biomass-degrading bacterium Caldicellulosiruptor bescii utilizes two enzymes to oxidize glyceraldehyde 3-phosphate during glycolysis AU - Scott, Israel M. AU - Rubinstein, Gabriel M. AU - Poole, Farris L., II AU - Lipscomb, Gina L. AU - Schut, Gerrit J. AU - Williams-Rhaesa, Amanda M. AU - Stevenson, David M. AU - Amador-Noguez, Daniel AU - Kelly, Robert M. AU - Adams, Michael W. W. T2 - JOURNAL OF BIOLOGICAL CHEMISTRY AB - Caldicellulosiruptor bescii is an extremely thermophilic, cellulolytic bacterium with a growth optimum at 78 °C and is the most thermophilic cellulose degrader known. It is an attractive target for biotechnological applications, but metabolic engineering will require an in-depth understanding of its primary pathways. A previous analysis of its genome uncovered evidence that C. bescii may have a completely uncharacterized aspect to its redox metabolism, involving a tungsten-containing oxidoreductase of unknown function. Herein, we purified and characterized this new member of the aldehyde ferredoxin oxidoreductase family of tungstoenzymes. We show that it is a heterodimeric glyceraldehyde-3-phosphate (GAP) ferredoxin oxidoreductase (GOR) present not only in all known Caldicellulosiruptor species, but also in 44 mostly anaerobic bacterial genera. GOR is phylogenetically distinct from the monomeric GAP-oxidizing enzyme found previously in several Archaea. We found that its large subunit (GOR-L) contains a single tungstopterin site and one iron-sulfur [4Fe-4S] cluster, that the small subunit (GOR-S) contains four [4Fe-4S] clusters, and that GOR uses ferredoxin as an electron acceptor. Deletion of either subunit resulted in a distinct growth phenotype on both C5 and C6 sugars, with an increased lag phase, but higher cell densities. Using metabolomics and kinetic analyses, we show that GOR functions in parallel with the conventional GAP dehydrogenase, providing an alternative ferredoxin-dependent glycolytic pathway. These two pathways likely facilitate the recycling of reduced redox carriers (NADH and ferredoxin) in response to environmental H2 concentrations. This metabolic flexibility has important implications for the future engineering of this and related species. Caldicellulosiruptor bescii is an extremely thermophilic, cellulolytic bacterium with a growth optimum at 78 °C and is the most thermophilic cellulose degrader known. It is an attractive target for biotechnological applications, but metabolic engineering will require an in-depth understanding of its primary pathways. A previous analysis of its genome uncovered evidence that C. bescii may have a completely uncharacterized aspect to its redox metabolism, involving a tungsten-containing oxidoreductase of unknown function. Herein, we purified and characterized this new member of the aldehyde ferredoxin oxidoreductase family of tungstoenzymes. We show that it is a heterodimeric glyceraldehyde-3-phosphate (GAP) ferredoxin oxidoreductase (GOR) present not only in all known Caldicellulosiruptor species, but also in 44 mostly anaerobic bacterial genera. GOR is phylogenetically distinct from the monomeric GAP-oxidizing enzyme found previously in several Archaea. We found that its large subunit (GOR-L) contains a single tungstopterin site and one iron-sulfur [4Fe-4S] cluster, that the small subunit (GOR-S) contains four [4Fe-4S] clusters, and that GOR uses ferredoxin as an electron acceptor. Deletion of either subunit resulted in a distinct growth phenotype on both C5 and C6 sugars, with an increased lag phase, but higher cell densities. Using metabolomics and kinetic analyses, we show that GOR functions in parallel with the conventional GAP dehydrogenase, providing an alternative ferredoxin-dependent glycolytic pathway. These two pathways likely facilitate the recycling of reduced redox carriers (NADH and ferredoxin) in response to environmental H2 concentrations. This metabolic flexibility has important implications for the future engineering of this and related species. DA - 2019/6/21/ PY - 2019/6/21/ DO - 10.1074/jbc.RA118.007120 VL - 294 IS - 25 SP - 9995-10005 SN - 1083-351X KW - glycolysis KW - cellulose KW - metabolism KW - metabolomics KW - metalloenzyme KW - oxidation-reduction (redox) KW - anaerobic glycolysis KW - iron-sulfur protein KW - pterin KW - tungsten ER - TY - JOUR TI - Impact of oxidative carbonization on structure development of loblolly pine-derived biochar investigated by nuclear magnetic resonance spectroscopy and X-ray photoelectron spectroscopy AU - Park, Junyeong AU - Yoo, Seunghyun AU - Lim, Kwang Hun AU - Rojas, Orlando J. AU - Hubbe, Martin A. AU - Park, Sunkyu T2 - DIAMOND AND RELATED MATERIALS AB - Biochar produced at an oxidative atmosphere shows distinct chemical properties compared to those of biochar produced at an inert atmosphere. However, there has been little investigation on the relationship between the oxidative atmosphere and the structure development of biochar, which can be useful information for the utilization of derived products. In this study, the effect of the oxygen atmosphere on the structure development of loblolly pine-derived biochar during thermal treatment was investigated. Quantitative analysis using solid-state direct polarization/magic angle spinning 13C nuclear magnetic resonance spectroscopy presented the existence of large fractions of aromatic and non-protonated carbons in the biochars treated at an oxidative atmosphere, implying highly condensed aromatic structures with large cluster sizes. Simultaneous thermogravimetic analyzer-differential scanning calorimetry was employed to demonstrate the difference in heat flow during the thermal treatment at two different atmospheres. Relatively large exothermic heat flow was observed when woody biomass was treated at 350 °C under an oxidative atmosphere which might be responsible for the difference in structural alteration. The series of observations suggested that compared to inert atmospheric conditions, admitting a limited amount of oxygen during thermal treatment of woody biomass could promote the evolution of condensed aromatic carbon structures. DA - 2019/6// PY - 2019/6// DO - 10.1016/j.diamond.2019.05.001 VL - 96 SP - 140-147 SN - 1879-0062 KW - Oxidative carbonization KW - Fast pyrolysis KW - Non-protonated carbon structure KW - Pi-pi(star) transition KW - Endothermic reaction ER - TY - JOUR TI - Modular one-pot assembly of CRISPR arrays enables library generation and reveals factors influencing crRNA biogenesis AU - Liao, Chunyu AU - Ttofali, Fani AU - Slotkowski, Rebecca A. AU - Denny, Steven R. AU - Cecil, Taylor D. AU - Leenay, Ryan T. AU - Keung, Albert J. AU - Beisel, Chase L. T2 - NATURE COMMUNICATIONS AB - Abstract CRISPR-Cas systems inherently multiplex through CRISPR arrays—whether to defend against different invaders or mediate multi-target editing, regulation, imaging, or sensing. However, arrays remain difficult to generate due to their reoccurring repeat sequences. Here, we report a modular, one-pot scheme called CRATES to construct CRISPR arrays and array libraries. CRATES allows assembly of repeat-spacer subunits using defined assembly junctions within the trimmed portion of spacers. Using CRATES, we construct arrays for the single-effector nucleases Cas9, Cas12a, and Cas13a that mediated multiplexed DNA/RNA cleavage and gene regulation in cell-free systems, bacteria, and yeast. CRATES further allows the one-pot construction of array libraries and composite arrays utilized by multiple Cas nucleases. Finally, array characterization reveals processing of extraneous CRISPR RNAs from Cas12a terminal repeats and sequence- and context-dependent loss of RNA-directed nuclease activity via global RNA structure formation. CRATES thus can facilitate diverse multiplexing applications and help identify factors impacting crRNA biogenesis. DA - 2019/7/3/ PY - 2019/7/3/ DO - 10.1038/s41467-019-10747-3 VL - 10 SP - SN - 2041-1723 ER - TY - JOUR TI - Molecular insights into the surface-catalyzed secondary nucleation of amyloid-beta(40) (A beta(40)) by the peptide fragment A beta(16-22) AU - Bunce, Samuel J. AU - Wang, Yiming AU - Stewart, Katie L. AU - Ashcroft, Alison E. AU - Radford, Sheena E. AU - Hall, Carol K. AU - Wilson, Andrew J. T2 - SCIENCE ADVANCES AB - Understanding the structural mechanism by which proteins and peptides aggregate is crucial, given the role of fibrillar aggregates in debilitating amyloid diseases and bioinspired materials. Yet, this is a major challenge as the assembly involves multiple heterogeneous and transient intermediates. Here, we analyze the co-aggregation of Aβ40 and Aβ16-22, two widely studied peptide fragments of Aβ42 implicated in Alzheimer's disease. We demonstrate that Aβ16-22 increases the aggregation rate of Aβ40 through a surface-catalyzed secondary nucleation mechanism. Discontinuous molecular dynamics simulations allowed aggregation to be tracked from the initial random coil monomer to the catalysis of nucleation on the fibril surface. Together, the results provide insight into how dynamic interactions between Aβ40 monomers/oligomers on the surface of preformed Aβ16-22 fibrils nucleate Aβ40 amyloid assembly. This new understanding may facilitate development of surfaces designed to enhance or suppress secondary nucleation and hence to control the rates and products of fibril assembly. DA - 2019/6// PY - 2019/6// DO - 10.1126/sciadv.aav8216 VL - 5 IS - 6 SP - SN - 2375-2548 ER - TY - JOUR TI - A CGenFF-based force field for simulations of peptoids with both cis and trans peptide bonds AU - Weiser, Laura J. AU - Santiso, Erik E. T2 - JOURNAL OF COMPUTATIONAL CHEMISTRY AB - Peptoids, or poly‐n‐substituted glycines, are peptide‐like polymers composed of a flexible backbone decorated with diverse chemical side chains. Peptoids can form a variety of self‐assembling structures based on the type and sequence of the side chains attached to their backbones. All‐atom molecular dynamics simulations have been useful in predicting the conformational structures of proteins and will be valuable tools for identifying combinations of peptoid side chains that may form interesting folded structures. However, peptoid models must address a major degree of freedom not common in proteins – the cis/trans isomerization of the peptide bond. This work presents CHARMM general force field (CGenFF) parameters developed to accurately represent peptoid conformational behavior, with an emphasis on a correct representation of both the cis and trans isomers of the peptoid backbone. These parameters are validated against experimental and quantum mechanics data and used to simulate three peptoid side chains in explicitly solvated systems. © 2019 Wiley Periodicals, Inc. DA - 2019/8/15/ PY - 2019/8/15/ DO - 10.1002/jcc.25850 VL - 40 IS - 22 SP - 1946-1956 SN - 1096-987X KW - peptoids KW - CGenFF KW - CHARMM ER - TY - JOUR TI - Extraction of Plant DNA by Microneedle Patch for Rapid Detection of Plant Diseases AU - Paul, Rajesh AU - Saville, Amanda C. AU - Hansel, Jeana C. AU - Ye, Yanqi AU - Ball, Carmin AU - Williams, Alyssa AU - Chang, Xinyuan AU - Chen, Guojun AU - Gu, Zhen AU - Ristaino, Jean B. AU - Wei, Qingshan T2 - ACS NANO AB - In-field molecular diagnosis of plant diseases via nucleic acid amplification is currently limited by cumbersome protocols for extracting and isolating pathogenic DNA from plant tissues. To address this challenge, a rapid plant DNA extraction method was developed using a disposable polymeric microneedle (MN) patch. By applying MN patches on plant leaves, amplification-assay-ready DNA can be extracted within a minute from different plant species. MN-extracted DNA was used for direct polymerase chain reaction amplification of plant plastid DNA without purification. Furthermore, using this patch device, extraction of plant pathogen DNA (Phytophthora infestans) from both laboratory-inoculated and field-infected leaf samples was performed for detection of late blight disease in tomato. MN extraction achieved 100% detection rate of late blight infections for samples after 3 days of inoculation when compared to the conventional gold standard cetyltrimethylammonium bromide (CTAB)-based DNA extraction method and 100% detection rate for all blind field samples tested. This simple, cell-lysis-free, and purification-free DNA extraction method could be a transformative approach to facilitate rapid sample preparation for molecular diagnosis of various plant diseases directly in the field. DA - 2019/6// PY - 2019/6// DO - 10.1021/acsnano.9b00193 VL - 13 IS - 6 SP - 6540-6549 SN - 1936-086X KW - plant disease KW - DNA extraction KW - microneedle patch KW - Phytophthora infestans KW - nucleic acid amplification KW - point-of-care diagnostics ER - TY - JOUR TI - Expanding the upper limits of robustness of cellulose nanocrystal aerogels: outstanding mechanical performance and associated pore compression response of chiral-nematic architectures AU - Tripathi, Anurodh AU - Tardy, BlaiseL. AU - Khan, Saad A. AU - Liebner, Falk AU - Rojas, Orlando J. T2 - JOURNAL OF MATERIALS CHEMISTRY A AB - Anisotropy in liquid crystal dispersions of cellulose nanocrystals is demonstrated to drastically enhance the mechanical attributes of derived aerogels. DA - 2019/7/7/ PY - 2019/7/7/ DO - 10.1039/c9ta03950c VL - 7 IS - 25 SP - 15309-15319 SN - 2050-7496 ER - TY - JOUR TI - Driving the Scalability of DNA-Based Information Storage Systems AU - Tomek, Kyle J. AU - Volkel, Kevin AU - Simpson, Alexander AU - Hass, Austin G. AU - Indermaur, Elaine W. AU - Tuck, James M. AU - Keung, Albert J. T2 - ACS SYNTHETIC BIOLOGY AB - The extreme density of DNA presents a compelling advantage over current storage media; however, to reach practical capacities, new systems for organizing and accessing information are needed. Here, we use chemical handles to selectively extract unique files from a complex database of DNA mimicking 5 TB of data and design and implement a nested file address system that increases the theoretical maximum capacity of DNA storage systems by five orders of magnitude. These advancements enable the development and future scaling of DNA-based data storage systems with modern capacities and file access capabilities. DA - 2019/6// PY - 2019/6// DO - 10.1021/acssynbio.9b00100 VL - 8 IS - 6 SP - 1241-1248 SN - 2161-5063 KW - synthetic biology KW - DNA storage KW - information storage KW - nested architecture KW - file access KW - DNA sequencing ER - TY - JOUR TI - High Thermal Conductivity Silicone Elastomer Doped with Graphene Nanoplatelets and Eutectic GaIn Liquid Metal Alloy AU - Sargolzaeiaval, Yasaman AU - Ramesh, Viswanath Padmanabhan AU - Neumann, Taylor V. AU - Miles, Rebecca AU - Dickey, Michael D. AU - Ozturk, Mehmet C. T2 - ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY AB - This paper reports the thermal conductivity and mechanical properties of Sylgard 184 polydimethylsiloxane (PDMS) elastomer loaded with graphene nano-platelets (GnPs) and eutectic Ga-In (EGaIn) liquid metal droplets. We fabricated samples with different GnP and EGaIn concentrations and measured their thermal conductivity using the steady-state absolute technique. The results show that the thermal conductivity of the elastomer can be enhanced up to 5.6X when both GNP and EGaIn are included in the elastomer. Without EGaIn, the enhancement is limited to 4.4X. The results suggest that EGaIn inclusion did not change the viscosity of the uncured material significantly at any GnP loading level. We also observed that addition of just EGaIn to PDMS did not have a significant impact on the material's stiffness while lowering its ultimate tensile strength by a factor of 2X and the maximum elongation at the break point by a factor of 1.6X. On the other hand, it was demonstrated that GnP addition to pure PDMS or EGaIn doped PDMS made the elastomer stiffer and less tear resistant with lower elongation at the break point. DA - 2019/6/21/ PY - 2019/6/21/ DO - 10.1149/2.0271906jss VL - 8 IS - 6 SP - P357-P362 SN - 2162-8769 ER - TY - JOUR TI - Pyrolysis kinetics for lignocellulosic biomass-to-oil from molecular modeling AU - Westmoreland, Phillip R. T2 - CURRENT OPINION IN CHEMICAL ENGINEERING AB - Woody biomass is complex molecularly. It has long been used successfully as a chemical feedstock without understanding its components and their pyrolysis behavior at a molecular level, but such an understanding would bring new flexibility and control to processing design and operation. Recent data and modeling have in combination made much of cellulose pyrolysis quantitatively predictable. Hemicellulose and lignin are approaching that point, while predicting whole-wood pyrolysis is still complicated by factors like the presence of metal ions and three-dimensional effects. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.coche.2019.03.011 VL - 23 SP - 123-129 SN - 2211-3398 ER - TY - JOUR TI - CENTRIFUGAL SPINNING-HIGH RATE PRODUCTION OF NANOFIBERS AU - Chen, Chen AU - Dirican, Mahmut AU - Zhang, Xiangwu T2 - ELECTROSPINNING: NANOFABRICATION AND APPLICATIONS AB - Nanofibers have attracted tremendous attention due to their flexibility, large surface area, and ease of modification, and they have been widely utilized in different applications such as filtration, tissue engineering, drug delivery, protective clothing, energy storage, etc. At this writing, the most commonly used method to produce nanofibers is electrospinning. However, the utilization of a high-voltage setup and the low production rate have become barriers to its use in large scale. Centrifugal spinning is an efficient approach to producing nanofibers from various materials. During centrifugal spinning, the polymer solution or polymer melt is ejected out of the rotating spinning head, and when the centrifugal force overcomes the surface tension of the polymer liquid material, the polymer jet undergoes a stretching process and is eventually deposited on the collector, forming solidified nanofibers. This chapter gives an overview of the history, working mechanism, influential parameters, and various applications of the centrifugal spinning method. DA - 2019/// PY - 2019/// DO - 10.1016/B978-0-323-51270-1.00010-8 SP - 321-338 UR - https://publons.com/publon/26924630/ ER - TY - JOUR TI - Emergence of Liquid Metals in Nanotechnology AU - Kalantar-Zadeh, Kourosh AU - Tang, Jianbo AU - Daeneke, Torben AU - O’Mullane, Anthony P. AU - Stewart, Logan A. AU - Liu, Jing AU - Majidi, Carmel AU - Ruoff, Rodney S. AU - Weiss, Paul S. AU - Dickey, Michael D. T2 - ACS Nano AB - Bulk liquid metals have prospective applications as soft and fluid electrical and thermal conductors in electronic and optical devices, composites, microfluidics, robotics, and metallurgy with unique opportunities for processing, chemistry, and function. Yet liquid metals' great potential in nanotechnology remains in its infancy. Although work to date focuses primarily on Ga, Hg, and their alloys, to expand the field, we define "liquid metals" as metals and alloys with melting points (mp) up to 330 °C, readily accessible and processable even using household kitchen appliances. Such a definition encompasses a family of metals-including the majority of post-transition metals and Zn group elements (excluding Zn itself)-with remarkable versatility in chemistry, physics, and engineering. These liquid alloys can create metallic compounds of different morphologies, compositions, and properties, thereby enabling control over nanoscale phenomena. In addition, the presence of electronic and ionic "pools" within the bulk of liquid metals, as well as deviation from classical metallurgy on the surfaces of liquid metals, provides opportunities for gaining new capabilities in nanotechnology. For example, the bulk and surfaces of liquid metals can be used as reaction media for creating and manipulating nanomaterials, promoting reactions, or controlling crystallization of dissolved species. Interestingly, liquid metals have enormous surface tensions, yet the tension can be tuned electrically over a wide range or modified via surface species, such as the native oxides. The ability to control the interfacial tension allows these liquids to be readily reduced in size to the nanoscale. The liquid nature of such nanoparticles enables shape-reconfigurable structures, the creation of soft metallic nanocomposites, and the dissolution or dispersion of other materials within (or on) the metal to produce multiphasic or heterostructure particles. This Perspective highlights the salient features of these materials and seeks to raise awareness of future opportunities to understand and to utilize liquid metals for nanotechnology. DA - 2019/7/23/ PY - 2019/7/23/ DO - 10.1021/acsnano.9b04843 VL - 13 IS - 7 SP - 7388-7395 UR - https://doi.org/10.1021/acsnano.9b04843 ER - TY - JOUR TI - Structure of ice confined in carbon and silica nanopores AU - Jazdzewska, Monika AU - Sliwinska-Bartkowiak, Malgorzata AU - Domin, Kamila AU - Chudoba, Dorota M. AU - Beskrovnyi, Anatoly I. AU - Neov, Dimitr S. AU - Gubbins, Keith E. T2 - BULLETIN OF MATERIALS SCIENCE AB - In this work, water confined in silica and carbon nanopores has been examined. The purpose of this study is to describe the melting behaviour and structure of ice confined in silica nanopores, KIT-6 and ordered carbon nanopores, CMK-3, having pore diameters of 5.9 and 5.2 nm, respectively. To determine the melting temperature of ice inside the nanopores, we performed differential scanning calorimetry measurements of the systems studied. We found that the melting temperature of confined ice is reduced relative to the bulk melting point and this shift is 16 K for water confined in KIT-6 and 21 K for water confined in CMK-3. The structural properties of water at the interfaces were analysed by using the neutron diffraction method (ND). The ND measurements for all the systems studied, showed the features of both hexagonal ice, $$I_\mathrm{h}$$, and cubic ice, $$I_\mathrm{c}$$. However, we show that the ice confined in nanopores does not have a structure corresponding to the typical hexagonal form or the metastable cubic form. The ice confined in nanopores has a structure made up of cubic sequences interlaced with hexagonal sequences, which produce the stacking disordered ice (ice $$I_\mathrm{sd})$$. DA - 2019/8// PY - 2019/8// DO - 10.1007/s12034-019-1846-9 VL - 42 IS - 4 SP - SN - 0973-7669 KW - Nanophase KW - ice structure KW - carbon and silica nanopores KW - neutron diffraction KW - effect of confinement KW - cubicity ER - TY - JOUR TI - Design and evaluation of engineered protein biosensors for live-cell imaging of EGFR phosphorylation AU - Tiruthani, Karthik AU - Mischler, Adam AU - Ahmed, Shoeb AU - Mahinthakumar, Jessica AU - Haugh, Jason M. AU - Rao, Balaji M. T2 - SCIENCE SIGNALING AB - Engineered biosensors accurately report the kinetics of EGFR activation. DA - 2019/6/4/ PY - 2019/6/4/ DO - 10.1126/scisignal.aap7584 VL - 12 IS - 584 SP - SN - 1937-9145 ER - TY - JOUR TI - Fabrication of Guar-Only Electrospun Nanofibers by Exploiting a High- and Low-Molecular Weight Blend AU - Pirzada, Tahira AU - Farias, Barbara V. AU - Chu, Hsiao Mei Annie AU - Khan, Saad A. T2 - ACS Omega AB - We present a facile approach to electrospin nanofibers of guar galactomannan by blending high- and low-molecular weights (MWs) of guar. We discover that while neither native high MW guar nor hydrolyzed low MW guar is electrospinnable on its own, their combination leads to synergism in producing defect-free nanofibers. Such an approach of fabricating nanofibers from blending multiple MWs of the same polymer may provide an easy route to produce nanofibers of biopolymers which are typically hard to electrospin. Rheological studies reveal that a limiting amount of native guar is needed for electrospinnability, and for those systems that have the proportionate amount of native guar, there is a critical total concentration above which fibers form. Interestingly, a plot of blend viscosity versus guar concentration reveals two power-law regimes with an inflection point, above which fiber formation can be achieved akin to the behavior observed for pure (i.e., nonblend) polymers. DA - 2019/6/30/ PY - 2019/6/30/ DO - 10.1021/acsomega.9b00902 VL - 4 IS - 6 SP - 10767-10774 UR - https://doi.org/10.1021/acsomega.9b00902 ER - TY - JOUR TI - Shape-controlled synthesis of liquid metal nanodroplets for photothermal therapy AU - Yan, Junjie AU - Zhang, Xudong AU - Liu, Yang AU - Ye, Yanqi AU - Yu, Jicheng AU - Chen, Qian AU - Wang, Jinqiang AU - Zhang, Yuqi AU - Hu, Quanyin AU - Kang, Yang AU - Yang, Min AU - Gu, Zhen T2 - NANO RESEARCH DA - 2019/6// PY - 2019/6// DO - 10.1007/s12274-018-2262-y VL - 12 IS - 6 SP - 1313-1320 SN - 1998-0000 KW - liquid metal KW - melanin nanoparticles KW - nanomedicine KW - shape-controlled synthesis KW - photothermal therapy ER - TY - JOUR TI - Solution self-assembly of ABC triblock terpolymers with a central crystallizable poly(ferrocenyldimethylsilane) core-forming segment AU - Oliver, Alex M. AU - Spontak, Richard J. AU - Manners, Ian T2 - POLYMER CHEMISTRY AB - The synthesis and solution self-assembly behavior of a range of linear ABC triblock terpolymers with a central crystallizable poly(ferrocenyldimethylsilane) core-forming segment have been explored. DA - 2019/// PY - 2019/// DO - 10.1039/c8py01830h VL - 10 IS - 20 SP - 2559-2569 ER - TY - JOUR TI - Redox oxidative cracking of n-hexane with Fe-substituted barium hexaaluminates as redox catalysts AU - Tian, Xin AU - Dudek, Ryan B. AU - Gao, Yunfei AU - Zhao, Haibo AU - Li, Fanxing T2 - CATALYSIS SCIENCE & TECHNOLOGY AB - Promoted hexaaluminate redox catalysts achieved excellent olefin yield while allowing autothermal redox oxidative cracking of naphtha with low COx formation. DA - 2019/5/7/ PY - 2019/5/7/ DO - 10.1039/c8cy02530d VL - 9 IS - 9 SP - 2211-2220 SN - 2044-4761 UR - https://doi.org/10.1039/C8CY02530D ER - TY - JOUR TI - Efficacy of vaporized hydrogen peroxide for repeated sterilization of a single-use single-incision laparoscopic surgery port AU - Scharf, Valery F. AU - Dent, Brian AU - Jacob, Megan E. AU - Moore, Brandon T2 - VETERINARY SURGERY AB - Abstract Objective To determine the ability of vaporized hydrogen peroxide (VHP) to sterilize a single‐use single‐incision laparoscopic surgery port and its associated components after repeated simulated uses. Study design Prospective in vitro experimental study. Sample population Six single‐use single‐incision laparoscopic surgery ports with associated cannulas and insufflation tubing. Methods Ports, cannulas, and tubing were subjected to 10 cycles of simulated use, bacterial inoculation with Staphylococcus pseudintermedius and Escherichia coli , decontamination and sterilization, and testing via culture based on their treatment group designation. Bacteriological scores were compared among the negative control, positive control, and 4 treated ports and components. Results There was no difference in bacteriological scores between treated ports, cannulas, and insufflation tubing and the negative control port and components. Bacteriological scores of ports and components undergoing 6‐10 cycles were not significantly different from scores of ports and components undergoing 5 or fewer sterilization cycles. No difference was found in detection of bacteria from treated ports by biopsy of the foam versus sampling via wash. Conclusion This study suggests that a single‐use single‐incision laparoscopic port and its associated components can be effectively sterilized after multiple simulated uses by using VHP. Clinical significance Reuse of a single‐use single‐incision laparoscopic port is a safe and effective method of cost reduction in veterinary patients. DA - 2019/6// PY - 2019/6// DO - 10.1111/vsu.12905 VL - 48 SP - O59-O65 SN - 1532-950X ER - TY - JOUR TI - Experimental and Predictive Description of the Morphology of Wet-Spun Fibers AU - Tripathi, Anurodh AU - Rutkevičius, Marius AU - Bose, Arnab AU - Rojas, Orlando J. AU - Khan, Saad A. T2 - ACS Applied Polymer Materials AB - The prediction of the morphology of wet-spun fibers has so far been only possible by complex and experimentally intensive approaches that include the construction of ternary phase diagrams. Ultimately, however, the available models give approximate information. Here we propose an alternative predictive approach that uses design principles based on the combination of (1) relative energy difference (RED) of Hansen solubility and (2) a kinetic parameter “T” that considers mass transfer effects. Such a model is applied and experimentally validated for a priori determination of the diameter and internal morphology of wet-spun fibers. Remarkably, only three variables relevant to wet-spinning are needed, namely, the choice of polymer, solvent, and nonsolvent types. A combination of systems is tested, and the morphology of the obtained fibers is determined via electron microscopy. Aspects related to demixing, internal specific surface area (BET), and layer formation on the fibers are described qualitatively. The facile implementation of the design parameters is further confirmed through comparison with data published on the subject. Our proposed model is expected to accelerate future developments in nanomaterials, especially in the context of ongoing efforts related to fiber spinning with biopolymers. DA - 2019/6/14/ PY - 2019/6/14/ DO - 10.1021/acsapm.9b00089 VL - 1 IS - 6 SP - 1280-1290 UR - https://doi.org/10.1021/acsapm.9b00089 KW - wet-spinning KW - macrovoids KW - microcellular KW - delayed KW - instantaneous demixing ER - TY - JOUR TI - Colloidal gel elasticity arises from the packing of locally glassy clusters AU - Whitaker, Kathryn A. AU - Varga, Zsigmond AU - Hsiao, Lilian C. AU - Solomon, Michael J. AU - Swan, James W. AU - Furst, Eric M. T2 - NATURE COMMUNICATIONS AB - Colloidal gels formed by arrested phase separation are found widely in agriculture, biotechnology, and advanced manufacturing; yet, the emergence of elasticity and the nature of the arrested state in these abundant materials remains unresolved. Here, the quantitative agreement between integrated experimental, computational, and graph theoretic approaches are used to understand the arrested state and the origins of the gel elastic response. The micro-structural source of elasticity is identified by the l-balanced graph partition of the gels into minimally interconnected clusters that act as rigid, load bearing units. The number density of cluster-cluster connections grows with increasing attraction, and explains the emergence of elasticity in the network through the classic Cauchy-Born theory. Clusters are amorphous and iso-static. The internal cluster concentration maps onto the known attractive glass line of sticky colloids at low attraction strengths and extends it to higher strengths and lower particle volume fractions. DA - 2019/5/20/ PY - 2019/5/20/ DO - 10.1038/s41467-019-10039-w VL - 10 SP - SN - 2041-1723 ER - TY - JOUR TI - Self-enhanced and efficient removal of arsenic from waste acid using magnetite as an in situ iron donator AU - Cai, Guiyuan AU - Zhu, Xing AU - Li, Kongzhai AU - Qi, Xianjin AU - Wei, Yonggang AU - Wang, Hua AU - Hao, Fengyan T2 - WATER RESEARCH AB - High arsenic-containing waste acid from the heavy nonferrous metallurgical sector (Cu, Pb, Zn, Ni, Sn, etc.), one of the most dangerous arsenic hazardous wastes with extremely high arsenic concentrations, has presented enormous challenges to the environment and caused severe environmental pollution over the past few decades due to the lack of affordable and environmentally friendly disposal technologies. Here, we report a green process for the self-enhanced and efficient removal of arsenic from waste acid using magnetite as an in situ iron donator. Firstly, the room-temperature predissolution of magnetite in waste acid provides initial iron ions as a starting precipitator of arsenic, simultaneously providing a suitable pH range and an active surface that are ready for the nucleation and growth of scorodite. Afterwards, arsenic is precipitated in form the of scorodite, which is driven by a mutually improved cycle composed of arsenic precipitation and magnetite dissolution on the surface of magnetite particles. This cycle creates a low supersaturation of iron and constant pH in the waste acid, ensuring the continuous precipitation of arsenic as well-crystallized and environmentally stable scorodite by using magnetite as an in situ iron donator via the reaction of 2Fe3O4 + 6H3AsO4 + H2O2 = 6FeAsO4 + 10H2O. Under optimal conditions, including a 6-h room-temperature predissolution, a 12-h atmospheric reaction at 90 °C and a pH of 2.0 with a magnetite dosage at the Fe3O4/As molar ratio (the molar ratio of Fe3O4 in magnetite to As in waste acid) of 1.33, 99.90% of arsenic was successively removed from waste acid with an initial arsenic concentration of 10300 mg/L. In combination with the good adaptability of this process, the performed case study and prospective process show the successful removal of arsenic from waste acid as well as great potential for large-scale applications. DA - 2019/6/15/ PY - 2019/6/15/ DO - 10.1016/j.watres.2019.03.067 VL - 157 SP - 269-280 SN - 0043-1354 KW - Arsenic KW - Waste acid KW - Magnetite KW - Scorodite KW - Leaching toxicity ER - TY - JOUR TI - Real-time monitoring and control of CHO cell apoptosis by in situ multifrequency scanning dielectric spectroscopy AU - Ma, Fuduo AU - Zhang, An AU - Chang, David AU - Velev, Orlin D. AU - Wiltberger, Kelly AU - Kshirsagar, Rashmi T2 - PROCESS BIOCHEMISTRY AB - Process control strategies based on the physiological status of cells have recently been used to enhance mammalian cell culture productivity and robustness. In this study, we investigated the feasibility of using full-spectrum dielectric spectroscopy for detecting shifts in cell physiology and as a feedback tool to increase process efficiency. Multi-frequency permittivity spectra were collected from cell culture processes in which apoptosis was induced by glucose depletion, nutrient depletion, or chemical treatment. Meanwhile, key parameters of critical frequency (fc) and Cole-Cole alpha (α) were calculated in real time from the β-dispersion curve and correlated to data from off-line viability measurements. Results show that physiological changes in apoptotic cells were reflected in the on-line parameters earlier than from off-line methods. Using information from the on-line parameters, we achieved partial or full recovery from early apoptosis by replenishing the depleted feed. We also demonstrate that by using trends in fc, we could detect a deviation in media preparation in a manufacturing process which could not be achieved using conventional measurements. The results demonstrate that full-spectrum dielectric spectroscopy can be used as a facile tool for early detection of physiological changes and process adjustment in real-time to enhance bioreactor process productivity and robustness. DA - 2019/5// PY - 2019/5// DO - 10.1016/j.procbio.2019.02.017 VL - 80 SP - 138-145 SN - 1873-3298 KW - Dielectric spectroscopy KW - Apoptosis KW - Multi-frequency permittivity KW - Chinese Hamster Ovary (CHO) cell culture KW - Fed-batch KW - Feedback control ER - TY - JOUR TI - Affordable Microfluidic Bead-Sorting Platform for Automated Selection of Porous Particles Functionalized with Bioactive Compounds AU - Saberi-Bosari, Sahand AU - Omary, Mohammad AU - Lavoie, Ashton AU - Prodromou, Raphael AU - Day, Kevin AU - Menegatti, Stefano AU - San-Miguel, Adriana T2 - SCIENTIFIC REPORTS AB - Abstract The ability to rapidly and accurately evaluate bioactive compounds immobilized on porous particles is crucial in the discovery of drugs, diagnostic reagents, ligands, and catalysts. Existing options for solid phase screening of bioactive compounds, while highly effective and well established, can be cost-prohibitive for proof-of-concept and early stage work, limiting its applicability and flexibility in new research areas. Here, we present a low-cost microfluidics-based platform enabling automated screening of small porous beads from solid-phase peptide libraries with high sensitivity and specificity, to identify leads with high binding affinity for a biological target. The integration of unbiased computer assisted image processing and analysis tools, provided the platform with the flexibility of sorting through beads with distinct fluorescence patterns. The customized design of the microfluidic device helped with handling beads with different diameters (~100–300 µm). As a microfluidic device, this portable novel platform can be integrated with a variety of analytical instruments to perform screening. In this study, the system utilizes fluorescence microscopy and unsupervised image analysis, and can operate at a sorting speed of up to 125 beads/hr (~3.5 times faster than a trained operator) providing >90% yield and >90% bead sorting accuracy. Notably, the device has proven successful in screening a model solid-phase peptide library by showing the ability to select beads carrying peptides binding a target protein (human IgG). DA - 2019/5/10/ PY - 2019/5/10/ DO - 10.1038/s41598-019-42869-5 VL - 9 IS - 1 SP - SN - 2045-2322 UR - http://dx.doi.org/10.1038/s41598-019-42869-5 ER - TY - JOUR TI - Difference between approximate and rigorously measured transference numbers in fluorinated electrolytes AU - Shah, Deep B. AU - Nguyen, Hien Q. AU - Grundy, Lorena S. AU - Olson, Kevin R. AU - Mecham, Sue J. AU - DeSimone, Joseph M. AU - Balsara, Nitash P. T2 - PHYSICAL CHEMISTRY CHEMICAL PHYSICS AB - Fluorinated electrolytes are highly non-ideal and Newman's concentrated solution theory must be used to fully characterize ion-transport. DA - 2019/4/21/ PY - 2019/4/21/ DO - 10.1039/c9cp00216b VL - 21 IS - 15 SP - 7857-7866 SN - 1463-9084 ER - TY - JOUR TI - The Francisella novicida Cas12a is sensitive to the structure downstream of the terminal repeat in CRISPR arrays AU - Liao, Chunyu AU - Slotkowski, Rebecca A. AU - Achmedov, Tatjana AU - Beisel, Chase L. T2 - RNA BIOLOGY AB - The Class 2 Type V-A CRISPR effector protein Cas12a/Cpf1 has gained widespread attention in part because of the ease in achieving multiplexed genome editing, gene regulation, and DNA detection. Multiplexing derives from the ability of Cas12a alone to generate multiple guide RNAs from a transcribed CRISPR array encoding alternating conserved repeats and targeting spacers. While array design has focused on how to optimize guide-RNA sequences, little attention has been paid to sequences outside of the CRISPR array. Here, we show that a structured hairpin located immediately downstream of the 3ʹ repeat interferes with utilization of the adjacent encoded guide RNA by Francisella novicida (Fn)Cas12a. We first observed that a synthetic Rho-independent terminator immediately downstream of an array impaired DNA cleavage based on plasmid clearance in E. coli and DNA cleavage in a cell-free transcription-translation (TXTL) system. TXTL-based cleavage assays further revealed that inhibition was associated with incomplete processing of the transcribed CRISPR array and could be attributed to the stable hairpin formed by the terminator. We also found that the inhibitory effect partially extended to upstream spacers in a multi-spacer array. Finally, we found that removing the terminal repeat from the array increased the inhibitory effect, while replacing this repeat with an unprocessable terminal repeat from a native FnCas12a array restored cleavage activity directed by the adjacent encoded guide RNA. Our study thus revealed that sequences surrounding a CRISPR array can interfere with the function of a CRISPR nuclease, with implications for the design and evolution of CRISPR arrays. DA - 2019/4/3/ PY - 2019/4/3/ DO - 10.1080/15476286.2018.1526537 VL - 16 IS - 4 SP - 404-412 SN - 1555-8584 KW - Cpf1 KW - CRISPR KW - RNA structure KW - terminator KW - TXTL ER - TY - JOUR TI - Coarse-grained dynamic RNA titration simulations AU - Pasquali, S. AU - Frezza, E. AU - Silva, F. L. T2 - INTERFACE FOCUS AB - Electrostatic interactions play a pivotal role in many biomolecular processes. The molecular organization and function in biological systems are largely determined by these interactions. Owing to the highly negative charge of RNA, the effect is expected to be more pronounced in this system. Moreover, RNA base pairing is dependent on the charge of the base, giving rise to alternative secondary and tertiary structures. The equilibrium between uncharged and charged bases is regulated by the solution pH, which is therefore a key environmental condition influencing the molecule’s structure and behaviour. By means of constant-pH Monte Carlo simulations based on a fast proton titration scheme, coupled with the coarse-grained model HiRE-RNA, molecular dynamic simulations of RNA molecules at constant pH enable us to explore the RNA conformational plasticity at different pH values as well as to compute electrostatic properties as local p K a values for each nucleotide. DA - 2019/6/6/ PY - 2019/6/6/ DO - 10.1098/rsfs.2018.0066 VL - 9 IS - 3 SP - SN - 2042-8901 KW - RNA KW - titration KW - pH KW - coarse-grained model ER - TY - JOUR TI - A Microalgae Biocomposite-Integrated Spinning Disk Bioreactor (SDBR): Toward a Scalable Engineering Approach for Bioprocess Intensification in Light-Driven CO2 Absorption Applications AU - Ekins-Coward, Thea AU - Boodhoo, Kamelia V. K. AU - Velasquez-Orta, Sharon AU - Caldwell, Gary AU - Wallace, Adam AU - Barton, Ryan AU - Flickinger, Michael C. T2 - INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH AB - A scalable, solar-energy-driven microbial spinning disk gas absorber–converter technology has been developed by a novel combination of advanced photoreactive biocomposite materials with a continuous thin film flow spinning disc bioreactor (SDBR). Chlorella vulgaris microalgae were incorporated into a porous paper biocomposite for the first time with the addition of chitosan for cell integration within the paper matrix. A 10-cm-diameter SDBR with an immobilized C. vulgaris biocomposite paper enabled high photoactivity and CO2 biofixation at a spin speed of 300 rpm over 15 h of operation in the presence of bicarbonate in the liquid medium and 5% CO2 in the gas environment. Practically all C. vulgaris cells in the biocomposite successfully remained attached to the disk under conditions equivalent to 5g at the disc edge. Overall, the increased CO2 biofixation with a greatly reduced biocomposite surface area and the high cell retention in this proof-of-concept technology highlight the bioprocess intensification potential of the biocomposite integrated-SDBR. DA - 2019/4/17/ PY - 2019/4/17/ DO - 10.1021/acs.iecr.8b05487 VL - 58 IS - 15 SP - 5936-5949 SN - 0888-5885 ER - TY - JOUR TI - Silica resins and peptide ligands to develop disposable affinity adsorbents for antibody purification AU - Naika, Amith D. AU - Islam, Tuhidul AU - Terasaka, Takaaki AU - Ohara, Yuki AU - Hashimoto, Yasuhiro AU - Menegatti, Stefano AU - Carbonell, Ruben T2 - BIOCHEMICAL ENGINEERING JOURNAL AB - A study is presented on the use of porous silica resins with tailored properties to develop affinity adsorbents for the purification of immunoglobulin G (IgG). Chromatorex® silica resins were utilized to study the dependence of IgG binding upon functional group density, pore size, and specific surface area. The IgG-binding peptide HWRGWV was chosen to demonstrate the potential of combining inexpensive substrates and ligands into efficient, yet disposable, adsorbents. The static binding capacity (SBC) of silica-peptide adsorbents depends significantly on surface area and pore size, yet minimally on ligand density. Chromatorex®-NH2 MB 800 HC (pore size 800 Å, surface area 31 m2/g) and MB 700 HC (700 Å, 44 m2/g) showed SBC of 55 and 75 mg IgG per mL resin, respectively. The dynamic binding capacity (DBC) reached values of up to 60 mg/mL at 5 min residence time, and was found to be almost independent of flow rate, thus offering a much higher productivity (capacity vs. residence time) than Sepharose resins. A selected adsorbent was utilized for purifying monoclonal antibodies from Chinese hamster ovary (CHO) cell culture supernatants, and polyclonal antibodies from llama and rabbit serum. Under optimized conditions, the silica-peptide adsorbent gave a Mab purity above 90%, 4 log removal of host cell DNA, 1.5 log removal of host cell proteins (HCPs) and Mab recovery of 89% and 92%. Similarly, llama and rabbit IgG were isolated at 80%–85% purity. These results demonstrate that porous silica, a non-traditional substrate for protein purification, shows great promise as potentially single-use affinity adsorbent for protein purification. DA - 2019/5/15/ PY - 2019/5/15/ DO - 10.1016/j.bej.2018.07.011 VL - 145 SP - 53-61 SN - 1873-295X KW - Silica resins KW - Peptide ligands KW - Monoclonal antibodies KW - Llama antibodies KW - Rabbit antibodies ER - TY - JOUR TI - 3D-Printed Silicone Soft Architectures with Programmed Magneto-Capillary Reconfiguration AU - Roh, Sangchul AU - Okello, Lilian B. AU - Golbasi, Nuran AU - Hankwitz, Jameson P. AU - Liu, Jessica A-C AU - Tracy, Joseph B. AU - Velev, Orlin D. T2 - ADVANCED MATERIALS TECHNOLOGIES AB - Abstract Soft intelligent structures that are programmed to reshape and reconfigure under magnetic field can find applications such as in soft robotics and biomedical devices. Here, a new class of smart elastomeric architectures that undergo complex reconfiguration and shape change in applied magnetic fields, while floating on the surface of water, is reported. These magnetoactive soft actuators are fabricated by 3D printing with homocomposite silicone capillary ink. The ultrasoft actuators easily deform by the magnetic force exerted on carbonyl iron particles embedded in the silicone, as well as lateral capillary forces. The tensile and compressive moduli of the actuators are easily determined by their topological design through 3D printing. As a result, their responses can be engineered by the interplay of the intensity of the magnetic field gradient and the programmable moduli. 3D printing allows us to fabricate soft architectures with different actuation modes, such as isotropic/anisotropic contraction and multiple shape changes, as well as functional reconfiguration. Meshes that reconfigure in magnetic fields and respond to external stimuli by reshaping could serve as active tissue scaffolds for cell cultures and soft robots mimicking creatures that live on the surface of water. DA - 2019/4// PY - 2019/4// DO - 10.1002/admt.201800528 VL - 4 IS - 4 SP - SN - 2365-709X KW - additive manufacturing KW - magnetoactive materials KW - metamaterials KW - soft intelligent materials ER - TY - JOUR TI - Self-healing materials for soft-matter machines and electronics AU - Bartlett, Michael D. AU - Dickey, Michael D. AU - Majidi, Carmel T2 - NPG Asia Materials AB - Abstract The emergence of soft machines and electronics creates new opportunities to engineer robotic systems that are mechanically compliant, deformable, and safe for physical interaction with the human body. Progress, however, depends on new classes of soft multifunctional materials that can operate outside of a hard exterior and withstand the same real-world conditions that human skin and other soft biological materials are typically subjected to. As with their natural counterparts, these materials must be capable of self-repair and healing when damaged to maintain the longevity of the host system and prevent sudden or permanent failure. Here, we provide a perspective on current trends and future opportunities in self-healing soft systems that enhance the durability, mechanical robustness, and longevity of soft-matter machines and electronics. DA - 2019/12// PY - 2019/12// DO - 10.1038/s41427-019-0122-1 VL - 11 IS - 1 UR - https://doi.org/10.1038/s41427-019-0122-1 ER - TY - JOUR TI - Computational study of transition states for reaction path of energetic material TKX-50 AU - Li, Miao AU - Chen, Houyang AU - Xiao, Xingqing AU - Yang, Li AU - Peng, Changjun AU - Qin, Yuanhang AU - Wang, Tielin AU - Sun, Wei AU - Wang, Cunwen T2 - JOURNAL OF ENERGETIC MATERIALS AB - Dihydroxylammonium5,5′-bistetrazole-1,1′-diolate (TKX-50) is considered as one of the new ionic energetic materials. In this study, we employed density functional theory (DFT) method to calculate the reaction path of TKX-50 and search its optimized configurations of reactants, reactant complexes (RCs), transition states (TSs), product complexes (PCs), and products. We proposed 10 simple reactions in the reaction path, and determined their transition states. Among these TSs, six of them have lower energies than those of reactants. The equilibrium constants, which indicate the limitation of reactions, were computed from the difference of Gibbs free energy with temperature change. Based on the proposed reaction path, the reaction mechanism of TKX-50 was provided. DA - 2019/4/3/ PY - 2019/4/3/ DO - 10.1080/07370652.2019.1590482 VL - 37 IS - 2 SP - 240-250 SN - 1545-8822 KW - Energetic materials KW - TKX-50 KW - density functional theory KW - transition states KW - equilibrium constants ER - TY - JOUR TI - Targeted Capture of Chinese Hamster Ovary Host Cell Proteins: Peptide Ligand Discovery AU - Lavoie, R. Ashton AU - Fazio, Alice AU - Blackburn, R. Kevin AU - Goshe, Michael B. AU - Carbonell, Ruben G. AU - Menegatti, Stefano T2 - INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES AB - The growing integration of quality-by-design (QbD) concepts in biomanufacturing calls for a detailed and quantitative knowledge of the profile of impurities and their impact on the product safety and efficacy. Particularly valuable is the determination of the residual level of host cell proteins (HCPs) secreted, together with the product of interest, by the recombinant cells utilized for production. Though often referred to as a single impurity, HCPs comprise a variety of species with diverse abundance, size, function, and composition. The clearance of these impurities is a complex issue due to their cell line to cell line, product-to-product, and batch-to-batch variations. Improvements in HCP monitoring through proteomic-based methods have led to identification of a subset of "problematic" HCPs that are particularly challenging to remove, both at the product capture and product polishing steps, and compromise product stability and safety even at trace concentrations. This paper describes the development of synthetic peptide ligands capable of capturing a broad spectrum of Chinese hamster ovary (CHO) HCPs with a combination of peptide species that allow for advanced mixed-mode binding. Solid phase peptide libraries were screened for identification and characterization of peptides that capture CHO HCPs while showing minimal binding of human IgG, utilized here as a model product. Tetrameric and hexameric ligands featuring either multipolar or hydrophobic/positive amino acid compositions were found to be the most effective. Tetrameric multipolar ligands exhibited the highest targeted binding ratio (ratio of HCP clearance over IgG loss), more than double that of commercial mixed-mode and anion exchange resins utilized by industry for IgG polishing. All peptide resins tested showed preferential binding to HCPs compared to IgG, indicating potential uses in flow-through mode or weak-partitioning-mode chromatography. DA - 2019/4/8/ PY - 2019/4/8/ DO - 10.3390/ijms20071729 VL - 20 IS - 7 SP - SN - 1422-0067 KW - therapeutic antibodies KW - host cell proteins KW - protein purification KW - peptide ligands ER - TY - JOUR TI - A low-cost, non-invasive phase velocity and length meter and controller for multiphase lab-in-a-tube devices AU - Kerr, Corwin B. AU - Epps, Robert W. AU - Abolhasani, Milad T2 - Lab on a Chip AB - Opportunities for accessible microfluidic device integration have sharply grown with the rise of readily available lab-in-a-tube strategies. Herein, we present a facile, non-invasive, plug-and-play phase velocity and length measuring strategy for rapid deployment onto tube-based microfluidic systems, enabling quick and accurate residence (reaction) time measurement and tuning. Our approach utilizes inexpensive off-the-shelf optical phase sensors and requires no prior knowledge of the fluid composition or physical properties. Compared to camera-based measurements in fluoropolymer tubing, the optical phase sensor-based technique shows mean absolute percentage errors of 1.3% for velocity and 3.3% for length. Utilizing the developed multiphase flow monitoring technique, we screen the accessible parameter space of gas-liquid segmented flows. To further demonstrate the functionality of this process monitoring strategy, we implement two feedback controllers to establish simultaneous setpoint control for phase velocity and length. Next, to showcase the effectiveness and versatility of the developed multiphase flow process controller, we apply it to systematic studies of the effect of liquid slug velocity (controlling precursor mixing timescale) on the colloidal synthesis of cesium lead tribromide nanocrystals. By varying the liquid slug velocity and maintaining constant precursor composition, liquid slug length, and residence time, we observe a bandgap tunability from 2.43 eV (510 nm) to 2.52 eV (494 nm). DA - 2019/// PY - 2019/// DO - 10.1039/C9LC00296K UR - https://doi.org/10.1039/C9LC00296K ER - TY - JOUR TI - Adaptive Strategies of the Candidate Probiotic E. coli Nissle in the Mammalian Gut AU - Crook, Nathan AU - Ferreiro, Aura AU - Gasparrini, Andrew J. AU - Pesesky, Mitchell W. AU - Gibson, Molly K. AU - Wang, Bin AU - Sun, Xiaoqing AU - Condiotte, Zevin AU - Dobrowolski, Stephen AU - Peterson, Daniel AU - Dantas, Gautam T2 - CELL HOST & MICROBE AB - Probiotics are living microorganisms that are increasingly used as gastrointestinal therapeutics by virtue of their innate or engineered genetic function. Unlike abiotic therapeutics, probiotics can replicate in their intended site, subjecting their genomes and therapeutic properties to natural selection. We exposed the candidate probiotic E. coli Nissle (EcN) to the mouse gastrointestinal tract over several weeks, systematically altering the diet and background microbiota complexity. In-transit EcN accumulates genetic mutations that modulate carbohydrate utilization, stress response, and adhesion to gain competitive fitness, while previous exposure to antibiotics reveals an acquisition of resistance. We then leveraged these insights to generate an EcN strain that shows therapeutic efficacy in a mouse model of phenylketonuria and found that it was genetically stable over 1 week, thereby validating EcN's utility as a chassis for engineering. Collectively, we demonstrate a generalizable pipeline that can be applied to other probiotics to better understand their safety and engineering potential. DA - 2019/4/10/ PY - 2019/4/10/ DO - 10.1016/j.chom.2019.02.005 VL - 25 IS - 4 SP - 499-+ SN - 1934-6069 UR - https://doi.org/10.1016/j.chom.2019.02.005 ER - TY - JOUR TI - The formation of biaxial nematic phases in binary mixtures of thermotropic liquid-crystals composed of uniaxial molecules AU - Skutnik, Robert A. AU - Lehmann, Louis AU - Pueschel-Schlotthauer, Sergej AU - Jackson, George AU - Schoen, Martin T2 - MOLECULAR PHYSICS AB - Monte Carlo simulations in the isothermal-isobaric ensemble are used to investigate the formation of an ordered, biaxial nematic phase in a binary mixture of thermotropic liquid crystals. The orientational dependence of the interaction between molecules of each pure component is the same as in the well-known Maier-Saupe model; each pure component of the mixture is therefore capable of forming a uniaxial nematic phase. For the interaction between molecules of different components, we use the same Maier-Saupe model but change the sign of the coupling constant. As a consequence a T-shaped arrangement of these molecules is energetically favoured. The formation of the biaxial phase occurs in two steps. At higher temperatures T, one of the components forms a uniaxial nematic phase whereas the other is in a quasi two-dimensional restricted isotropic liquid state. We develop a simple theoretical model to understand the high degree of (ostensible) nematic order in the latter. At lower T, the second component becomes nematic and then the entire mixture of the two compounds has biaxial symmetry. The biaxial nematic phase does not demix into domains rich in molecules of one or the other species. DA - 2019/10/18/ PY - 2019/10/18/ DO - 10.1080/00268976.2019.1581292 VL - 117 IS - 20 SP - 2830-2845 SN - 1362-3028 KW - Liquid crystal KW - binary mixture KW - nematic phase KW - biaxiality KW - Monte Carlo simulation ER - TY - JOUR TI - Effects of Sodium and Tungsten Promoters on Mg6MnO8-Based Core-Shell Redox Catalysts for Chemical Looping-Oxidative Dehydrogenation of Ethane AU - Yusuf, Seif AU - Neal, Luke AU - Bao, Zhenghong AU - Wu, Zili AU - Li, Fanxing T2 - ACS CATALYSIS AB - The present study investigates the effect of sodium and tungsten promoters on Mg6MnO8-based redox catalysts in a chemical looping oxidative dehydrogenation (CL-ODH) scheme. CL-ODH has the potential to significantly lower energy consumption and CO2/NOx emissions for ethylene production compared with conventional steam cracking. Sodium tungstate (Na2WO4) was previously shown to be an effective promoter for Mg6MnO8-based redox catalysts. Overall, the CL-ODH reaction proceeds via parallel gas-phase cracking of ethane and selective combustion of H2 on the surface of the Na2WO4-promoted redox catalyst. Reaction testing indicates that both Na and W are necessary to form Na2WO4 and to achieve high ethylene selectivity. A Na:W ratio lower than 2:1 lead to significant formation of additional mixed tungsten oxide phases and decreases ethylene selectivity. Further characterizations based on low-energy ion scattering (LEIS) and differential scanning calorimetry (DSC) indicate that the NaW promoter forms a molten shell around the Mg6MnO8 redox catalyst. Methanol TPSR and in situ DRIFTS experiments indicate that the promoter significantly suppresses the number of basic sites on Mg6MnO8. 18O–16O exchange experiments reveal that the promoter decreases the rate of oxygen exchange. O2 cofeed studies indicate that below the melting temperature of Na2WO4, H2 and CO conversions are both inhibited, but above the melting temperature, H2 combustion significantly increased while CO combustion is still inhibited. On the basis of extensive characterizations, it was determined that H2 is primarily combusted at the gas–Na2WO4 molten shell interface via redox reactions of the tungsten salt, likely between the WO42– (tungstate) and WO3– (tungsten bronze). DA - 2019/4// PY - 2019/4// DO - 10.1021/acscatal.9b00164 VL - 9 IS - 4 SP - 3174-3186 SN - 2155-5435 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85064004480&partnerID=MN8TOARS KW - oxidative dehydrogenation KW - chemical looping KW - redox catalyst KW - oxygen carrier ER - TY - CHAP TI - Molecular Modeling in Crystallization AU - Trout, B.L. AU - Chadwick, K. AU - Chen, J. AU - Santiso, E.E. T2 - Handbook of Industrial Crystallization A2 - Myerson, A. A2 - Erdemir, D. A2 - Lee, A.Y. PY - 2019/7/31/ ET - 3rd PB - Cambridge University Press ER - TY - JOUR TI - Differential Misfolding Properties of Glaucoma-Associated Olfactomedin Domains from Humans and Mice AU - Patterson-Orazem, Athena C. AU - Hill, Shannon E. AU - Wang, Yiming AU - Dominic, Iramofu M. AU - Hall, Carol K. AU - Lieberman, Raquel L. T2 - BIOCHEMISTRY AB - Mutations in myocilin, predominantly within its olfactomedin (OLF) domain, are causative for the heritable form of open angle glaucoma in humans. Surprisingly, mice expressing Tyr423His mutant myocilin, corresponding to a severe glaucoma-causing mutation (Tyr437His) in human subjects, exhibit a weak, if any, glaucoma phenotype. To address possible protein-level discrepancies between mouse and human OLFs, which might lead to this outcome, biophysical properties of mouse OLF were characterized for comparison with those of human OLF. The 1.55 Å resolution crystal structure of mouse OLF reveals an asymmetric 5-bladed β-propeller that is nearly indistinguishable from previous structures of human OLF. Wild-type and selected mutant mouse OLFs mirror thermal stabilities of their human OLF counterparts, including characteristic stabilization in the presence of calcium. Mouse OLF forms thioflavin T-positive aggregates with a similar end-point morphology as human OLF, but amyloid aggregation kinetic rates of mouse OLF are faster than human OLF. Simulations and experiments support the interpretation that kinetics of mouse OLF are faster because of a decreased charge repulsion arising from more neutral surface electrostatics. Taken together, phenotypic differences observed in mouse and human studies of mutant myocilin could be a function of aggregation kinetics rates, which would alter the lifetime of putatively toxic protofibrillar intermediates. DA - 2019/4/2/ PY - 2019/4/2/ DO - 10.1021/acs.biochem.8b01309 VL - 58 IS - 13 SP - 1718-1727 SN - 0006-2960 ER - TY - JOUR TI - Role of Linker Length and Antigen Density in Nanoparticle Peptide Vaccine AU - Kapadia, Chintan H. AU - Tian, Shaomin AU - Perry, Jillian L. AU - Luft, J. Christopher AU - Desimone, Joseph M. T2 - ACS OMEGA AB - Multiple studies have been published emphasizing the significant role of nanoparticle (NP) carriers in antigenic peptide-based subunit vaccines for the induction of potent humoral and cellular responses. Various design parameters of nanoparticle subunit vaccines such as linker chemistry, the proximity of antigenic peptide to NPs, and the density of antigenic peptides on the surface of NPs play an important role in antigen presentation to dendritic cells (DCs) and in subsequent induction of CD8+ T cell response. In this current study, we evaluated the role of peptide antigen proximity and density on DC uptake, antigen cross-presentation, in vitro T cell proliferation, and in vivo induction of CD8+ T cells. To evaluate the role of antigen proximity, CSIINFEKL peptides were systematically conjugated to poly(ethylene glycol) (PEG) hydrogels through N-hydroxysuccinimide-PEG-maleimide linkers of varying molecular weights: 2k, 5k, and 10k. We observed that the peptides conjugated to NPs via the 2k and 5k PEG linkers resulted in higher uptake in bone marrow-derived DCs (BMDCs) and increased p-MHC-I formation on the surface of bone marrow-derived DCs (BMDCs) as compared to the 10k PEG linker formulation. However, no significant differences in vitro T cell proliferation and induction of in vivo CD8+ T cells were found among linker lengths. To study the effect of antigen density, CSIINFEKL peptides were conjugated to PEG hydrogels via 5k PEG linkers at various densities. We found that high antigen density NPs presented the highest p-MHC-I on the surface of BMDCs and induced higher proliferation of T cells, whereas NPs with low peptide density resulted in higher DC cell uptake and elevated frequency of IFN-γ producing CD8+ T cells in mice as compared to the medium- and high-density formulations. Altogether, findings for these experiments highlighted the importance of linker length and peptide antigen density on DC cell uptake, antigen presentation, and induction of in vivo CD8+ T cell response. DA - 2019/3// PY - 2019/3// DO - 10.1021/acsomega.8b03391 VL - 4 IS - 3 SP - 5547-5555 SN - 2470-1343 ER - TY - CONF TI - State-of-the-Art Delivery and Assessment of an Online / Distance Education Chemical Engineering Bridging Course AU - Bullard, L. AU - Cooper, M. AU - Golpour, H. C2 - 2019/// C3 - Proceedings of the ASEE Southeastern Section Annual Conference 2019 CY - Raleigh, NC DA - 2019/// ER - TY - JOUR TI - Distinct timescales of RNA regulators enable the construction of a genetic pulse generator AU - Westbrook, Alexandra AU - Tang, Xun AU - Marshall, Ryan AU - Maxwell, Colin S. AU - Chappell, James AU - Agrawal, Deepak K. AU - Dunlop, Mary J. AU - Noireaux, Vincent AU - Beisel, Chase L. AU - Lucks, Julius AU - Franco, Elisa T2 - BIOTECHNOLOGY AND BIOENGINEERING AB - Abstract To build complex genetic networks with predictable behaviors, synthetic biologists use libraries of modular parts that can be characterized in isolation and assembled together to create programmable higher‐order functions. Characterization experiments and computational models for gene regulatory parts operating in isolation are routinely used to predict the dynamics of interconnected parts and guide the construction of new synthetic devices. Here, we individually characterize two modes of RNA‐based transcriptional regulation, using small transcription activating RNAs (STARs) and clustered regularly interspaced short palindromic repeats interference (CRISPRi), and show how their distinct regulatory timescales can be used to engineer a composed feedforward loop that creates a pulse of gene expression. We use a cell‐free transcription‐translation system (TXTL) to rapidly characterize the system, and we apply Bayesian inference to extract kinetic parameters for an ordinary differential equation‐based mechanistic model. We then demonstrate in simulation and verify with TXTL experiments that the simultaneous regulation of a single gene target with STARs and CRISPRi leads to a pulse of gene expression. Our results suggest the modularity of the two regulators in an integrated genetic circuit, and we anticipate that construction and modeling frameworks that can leverage this modularity will become increasingly important as synthetic circuits increase in complexity. DA - 2019/5// PY - 2019/5// DO - 10.1002/bit.26918 VL - 116 IS - 5 SP - 1139-1151 SN - 1097-0290 KW - Bayesian methods KW - CRISPRi KW - model-guided design KW - RNA-based circuits KW - sRNA ER - TY - JOUR TI - Shrink Films Get a Grip AU - Hubbard, Amber M. AU - Luong, Elton AU - Ratanaphruks, Ana AU - Mailen, Russell W. AU - Genzer, Jan AU - Dickey, Michael D. T2 - ACS Applied Polymer Materials AB - Robotics and active materials have forged the path for grasping and manipulating delicate objects of various geometries and sizes. To date, the majority of soft robotic grippers have used hydrogels or elastomers, which can repeatably grasp and manipulate small objects. Many of these grippers achieve their grip (due to shape change) only in the presence of either solvent exposure or external pneumatic pressure. Here, we demonstrate thermoplastic polystyrene sheets that actuate from flat sheets into grippers in response to light exposure and maintain their shape upon removal of the light. Black ink patterned on the sheet converts global light illumination to localized heating that causes the planar sheet to deform into the shape of a gripper. These grippers have significantly improved endurance and strength compared to their hydrogel or elastomeric counterparts as they can support >24 000 times their own mass. These grippers release objects upon additional uniform heating, and each gripper serves as a single use device. We report the significance of sample geometry and ink patterning for controlled, localized heating upon the resulting three-dimensional shape and its impact on precision and strength. Various designs for untethered, stimuli-responsive thermoplastic grippers are presented based on targeted applications such as encapsulation. DA - 2019/5/10/ PY - 2019/5/10/ DO - 10.1021/acsapm.9b00106 VL - 1 IS - 5 SP - 1088-1095 UR - https://doi.org/10.1021/acsapm.9b00106 KW - stimuli-responsive KW - grippers KW - load bearing KW - active materials KW - polymer sheets KW - thermoplastics KW - self-folding ER - TY - JOUR TI - All Roads Start with MEB: A Team Teaching Approach for Mentoring New Faculty AU - Bullard, L.G. AU - Felder, R.M. T2 - Chemical Engineering Education DA - 2019/// PY - 2019/// VL - 53 IS - 1 SP - 18–21 ER - TY - JOUR TI - What Students and Faculty Should Know About Professional Licensure AU - Wagner, J.E. AU - Parrish, W. AU - Bullard, L.G. T2 - Chemical Engineering Education DA - 2019/// PY - 2019/// VL - 53 IS - 1 SP - 42–44 ER - TY - JOUR TI - 3D Printed Absorber for Capturing Chemotherapy Drugs before They Spread through the Body AU - Oh, Hee Jeung AU - Aboian, Mariam S. AU - Yi, Michael Y. J. AU - Maslyn, Jacqueline A. AU - Loo, Whitney S. AU - Jiang, , Xi AU - Parkinson, Dilworth Y. AU - Wilson, Mark W. AU - Moore, Terilyn AU - Yee, Colin R. AU - Robbins, Gregory R. AU - Barth, Florian M. AU - Desimone, Joseph M. AU - Hetts, Steven W. AU - Balsara, Nitash P. T2 - ACS CENTRAL SCIENCE AB - Despite efforts to develop increasingly targeted and personalized cancer therapeutics, dosing of drugs in cancer chemotherapy is limited by systemic toxic side effects. We have designed, built, and deployed porous absorbers for capturing chemotherapy drugs from the bloodstream after these drugs have had their effect on a tumor, but before they are released into the body where they can cause hazardous side effects. The support structure of the absorbers was built using 3D printing technology. This structure was coated with a nanostructured block copolymer with outer blocks that anchor the polymer chains to the 3D printed support structure and a middle block that has an affinity for the drug. The middle block is polystyrenesulfonate which binds to doxorubicin, a widely used and effective chemotherapy drug with significant toxic side effects. The absorbers are designed for deployment during chemotherapy using minimally invasive image-guided endovascular surgical procedures. We show that the introduction of the absorbers into the blood of swine models enables the capture of 64 ± 6% of the administered drug (doxorubicin) without any immediate adverse effects. Problems related to blood clots, vein wall dissection, and other biocompatibility issues were not observed. This development represents a significant step forward in minimizing toxic side effects of chemotherapy. DA - 2019/3/27/ PY - 2019/3/27/ DO - 10.1021/acscentsci.8b00700 VL - 5 IS - 3 SP - 419-427 SN - 2374-7951 ER - TY - JOUR TI - Use of a Branched Linker for Enhanced Biosensing Properties in IgG Detection from Mixed Chinese Hamster Ovary Cell Cultures AU - Islam, Nafisa AU - Gurgel, Patrick V. AU - Rojas, Orlando J. AU - Carbonell, Ruben G. T2 - BIOCONJUGATE CHEMISTRY AB - Tris(2-aminoethyl)-amine (TREN), a branched amine, was coupled to planar surfaces of alkanethiol self-assembled monolayers (SAMs) to increase the grafting density of IgG-binding peptide (HWRGWV or HWRGWVG) on gold surfaces. One of the three primary amine pendant groups of TREN anchors onto the SAM, while the other two are available for grafting with the C-termini of the peptide. The ellipsometric peptide density on the SAM-branched amine was 1.24 molecules nm-2. The surfaces carrying the peptides were investigated via surface plasmon resonance (SPR) to quantify the adsorption of IgG and showed maximum binding capacity, Qm of 4.45 mg m-2, and dissociation constant, Kd of 8.7 × 10-7 M. Real-time dynamic adsorption data was used to determine adsorption rate constants, ka values, and the values were dependent on IgG concentration. IgG binding from complex mixtures of Chinese hamster ovary supernatant (CHO) was investigated and regeneration studies were carried out. Compared to the unbranched amine-based surfaces, the branched amines increased the overall sensitivity and selectivity for IgG adsorption from complex mixtures. Regeneration of the branched amine-based surfaces was achieved with 0.1 M NaOH, with less than 10% decline in peptide activity after 12 cycles of regeneration-binding. DA - 2019/3// PY - 2019/3// DO - 10.1021/acs.bioconjchem.8b00918 VL - 30 IS - 3 SP - 815-825 SN - 1043-1802 ER - TY - JOUR TI - Interactive effects of solar UV radiation and climate change on material damage AU - Andrady, A. L. AU - Pandey, K. K. AU - Heikkila, A. M. T2 - PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES DA - 2019/3/1/ PY - 2019/3/1/ DO - 10.1039/c8pp90065e VL - 18 IS - 3 SP - 804-825 SN - 1474-9092 ER - TY - JOUR TI - Advanced ZnSnS3@rGO Anode Material for Superior Sodium-Ion and Lithium-Ion Storage with Ultralong Cycle Life AU - Jia, Hao AU - Dirican, Mahmut AU - Sun, Na AU - Chen, Chen AU - Yan, Chaoyi AU - Zhu, Pei AU - Dong, Xia AU - Du, Zhuang AU - Cheng, Hui AU - Guo, Jiansheng AU - Zhang, Xiangwu T2 - CHEMELECTROCHEM AB - Abstract A novel and facile approach has been utilized to synthesize zinc tin sulfide@reduced graphene oxide (ZnSnS 3 @rGO) through aqueous reaction of Na 2 SnO 3 and Zn(CH 3 COO) 2 , combined with a subsequent solvothermal reaction and an annealing process. The as‐prepared ZnSnS 3 @rGO nanocomposite exhibited an excellent sodium‐ and lithium‐ion‐storage performance with large specific capacity, high rate capability, and ultralong cycle life. When used in Na‐ion cells, the ZnSnS 3 @rGO nanocomposite delivered a capacity of 472.2 mAh g −1 at 100 mA g −1 and retained a specific capacity of 401.2 mAh g −1 after 200 cycles. In Li‐ion cells, the ZnSnS 3 @rGO nanocomposite delivered a capacity of 959.2 mAh g −1 at a current density of 100 mA g −1 and maintained a specific capacity of 551.3 mAh g −1 at a high current density of 1 A g −1 upon 500 cycles. The electrochemical performance results reveal that the integration of uniformly dispersed metal elements and an interconnected carbon matrix could help release the stress of volumetric excursion and provide fast electron/ion transport, leading to a remarkable electrochemical performance. DA - 2019/2/15/ PY - 2019/2/15/ DO - 10.1002/celc.201801333 VL - 6 IS - 4 SP - 1183-1191 SN - 2196-0216 UR - https://publons.com/publon/26924629/ KW - anode KW - lithium-ion battery KW - reduced graphene oxide KW - sodium-ion battery KW - zinc tin sulfide ER - TY - JOUR TI - Thermo-mechanical transformation of shape memory polymers from initially flat discs to bowls and saddles AU - Mailen, Russell W. AU - Wagner, Catherine H. AU - Bang, Rachel S. AU - Zikry, Mohammed AU - Dickey, Michael D. AU - Genzer, Jan T2 - SMART MATERIALS AND STRUCTURES AB - This paper describes the transformation of shape memory polymer (SMP) discs, from flat sheets to complex three-dimensional (3D) shapes, in response to heat generated by localized absorption of external infrared (IR) light. The gray-scale ink darkness printed on the surface of the SMP sheet determines the amount of absorbed light and the amount of heat generated on the surface of the sheet. Consequently, the lateral pattern of the ink governs the out-of-plane deformation of the SMP sheets due to variations in localized heating and shrinking. While recent studies have focused primarily on out-of-plane deformations of planar, rectangular substrates printed with linear patterns of ink and featuring either discrete or gradient ink variation, only limited studies have been performed on circular substrates with axisymmetric ink patterns. When heated by IR light, the axial symmetry of these ink designs produces unique out-of-plane deformations of the sheets, such as saddle shapes or bowl-like structures. We investigate these designs by utilizing a finite element analysis of material shrinkage and deformation, and we validate the model with experimental measurements and observations. This investigation provides insights into the mechanisms that cause axisymmetric geometries and ink patterns to form non-axisymmetric 3D structures, which can lead to the ability to program planar geometries that form complex 3D shapes when exposed to external stimuli. DA - 2019/4// PY - 2019/4// DO - 10.1088/1361-665X/ab030a VL - 28 IS - 4 SP - SN - 1361-665X KW - shape-memory polymers KW - modeling KW - viscoelasticity KW - thermo-mechanical KW - axial symmetry ER - TY - JOUR TI - UV plasmonic properties of colloidal liquid-metal eutectic gallium-indium alloy nanoparticles AU - Reineck, Philipp AU - Lin, Yiliang AU - Gibson, Brant C. AU - Dickey, Michael D. AU - Greentree, Andrew D. AU - Maksymov, Ivan S. T2 - Scientific Reports AB - Nanoparticles made of non-noble metals such as gallium have recently attracted significant attention due to promising applications in UV plasmonics. To date, experiments have mostly focused on solid and liquid pure gallium particles immobilized on solid substrates. However, for many applications, colloidal liquid-metal nanoparticle solutions are vital. Here, we experimentally demonstrate strong UV plasmonic resonances of eutectic gallium-indium (EGaIn) liquid-metal alloy nanoparticles suspended in ethanol. We rationalise experimental results through a theoretical model based on Mie theory. Our results contribute to the understanding of UV plasmon resonances in colloidal liquid-metal EGaIn nanoparticle suspensions. They will also enable further research into emerging applications of UV plasmonics in biomedical imaging, sensing, stretchable electronics, photoacoustics, and electrochemistry. DA - 2019/3/29/ PY - 2019/3/29/ DO - 10.1038/s41598-019-41789-8 UR - https://doi.org/10.1038/s41598-019-41789-8 ER - TY - JOUR TI - Benchmarking Smartphone Fluorescence-Based Microscopy with DNA Origami Nanobeads: Reducing the Gap toward Single-Molecule Sensitivity AU - Vietz, Carolin AU - Schuette, Max L. AU - Wei, Qingshan AU - Richter, Lars AU - Lalkens, Birka AU - Ozcan, Aydogan AU - Tinnefeld, Philip AU - Acuna, Guillermo P. T2 - ACS OMEGA AB - Smartphone-based fluorescence microscopy has been rapidly developing over the last few years, enabling point-of-need detection of cells, bacteria, viruses, and biomarkers. These mobile microscopy devices are cost-effective, field-portable, and easy to use, and benefit from economies of scale. Recent developments in smartphone camera technology have improved their performance, getting closer to that of lab microscopes. Here, we report the use of DNA origami nanobeads with predefined numbers of fluorophores to quantify the sensitivity of a smartphone-based fluorescence microscope in terms of the minimum number of detectable molecules per diffraction-limited spot. With the brightness of a single dye molecule as a reference, we compare the performance of color and monochrome sensors embedded in state-of-the-art smartphones. Our results show that the monochrome sensor of a smartphone can achieve better sensitivity, with a detection limit of ∼10 fluorophores per spot. The use of DNA origami nanobeads to quantify the minimum number of detectable molecules of a sensor is broadly applicable to evaluate the sensitivity of various optical instruments. DA - 2019/1// PY - 2019/1// DO - 10.1021/acsomega.8b03136 VL - 4 IS - 1 SP - 637-642 SN - 2470-1343 UR - https://doi.org/10.1021/acsomega.8b03136 ER - TY - JOUR TI - Water-Stable Chemical-Protective Textiles via Euhedral Surface-Oriented 2D Cu-TCPP Metal-Organic Frameworks AU - Lee, Dennis T. AU - Jamir, Jovenal D. AU - Peterson, Gregory W. AU - Parsons, Gregory N. T2 - SMALL AB - Abstract Abatement of chemical hazards using adsorptive metal‐organic frameworks (MOFs) attracts substantial attention, but material stability and crystal integration into functional systems remain key challenges. Herein, water‐stable, polymer fiber surface–oriented M–TCPP [M = Cu, Zn, and Co; H 2 TCPP = 5,10,15,20‐tetrakis(4‐carboxyphenyl)porphyrin] 2D MOF crystals are fabricated using a facile hydroxy double salt (HDS) solid‐source conversion strategy. For the first time, Cu–TCPP is formed from a solid source and confirmed to be highly adsorptive for NH 3 and 2‐chloroethyl ethyl sulfide (CEES), a blistering agent simulant, in humid (80% relative humidity (RH)) conditions. Moreover, the solid HDS source is found as a unique new approach to control MOF thin‐film crystal orientation, thereby facilitating radially arranged MOF crystals on fibers. On a per unit mass of MOF basis in humid conditions, the MOF/fiber composite enhances NH 3 adsorptive capacity by a factor of 3 compared to conventionally prepared MOF powders. The synthesis route extends to other MOF/fiber composite systems, therefore providing a new route for chemically protective materials. DA - 2019/3/8/ PY - 2019/3/8/ DO - 10.1002/smll.201805133 VL - 15 IS - 10 SP - SN - 1613-6829 UR - https://doi.org/10.1002/smll.201805133 KW - atomic layer deposition KW - hazardous chemicals KW - hydroxy double salt KW - metal-organic framework KW - MOF/fiber composites ER - TY - JOUR TI - Perovskite oxides for redox oxidative cracking of n-hexane under a cyclic redox scheme AU - Dudek, Ryan B. AU - Tian, Xin AU - Blivin, Millicent AU - Neal, Luke M. AU - Zhao, Haibo AU - Li, Fanxing T2 - APPLIED CATALYSIS B-ENVIRONMENTAL AB - Steam cracking of naphtha is a commercially proven technology for light olefin production and the primary source of ethylene in the Europe and Asia-Pacific markets. However, its significant energy consumption and high CO2 intensity (up to 2 tons CO2/ton C2H4), stemming from endothermic cracking reactions and complex product separations, make this state-of-the-art process increasingly undesirable from an environmental standpoint. We propose a redox oxidative cracking (ROC) approach as an alternative pathway for naphtha conversion. Enabled by perovskite oxide-based redox catalysts, the ROC process converts naphtha (represented by n-hexane) in an auto-thermal, cyclic redox mode. The addition of 20 wt.% Na2WO4 to SrMnO3 and CaMnO3 created highly selective redox catalysts capable of achieving enhanced olefin yields from n-hexane oxy-cracking. This was largely attributed to the redox catalysts’ high activity, selectivity, and stability towards selective hydrogen combustion (SHC) under a redox mode. Na2WO4/CaMnO3 demonstrated significantly higher olefin yield (55–58%) when compared to that from thermal cracking (34%) at 725 °C and 4500 h−1. COx yield as low as 1.7% was achieved along with complete combustion of H2 over 25 cycles. Similarly, Na2WO4/SrMnO3 achieved 41% olefin yield, 0.4% COx yield, and 73% H2 combustion at this condition. Oxygen-temperature-programmed desorption (O2-TPD) indicated that Na2WO4 hindered gaseous oxygen release from CaMnO3. Low-energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS) revealed an outermost perovskite surface layer covered by Na2WO4, which suppressed near-surface Mn and alkaline earth metal cations. The formation of non-selective surface oxygen species was also inhibited. XPS analysis further confirmed that promotion of SrMnO3 with Na2WO4 suppressed surface Sr species by 90%, with a similar effect also observed on CaMnO3. These findings point to the promoting effect of Na2WO4 and the potential of promoted SrMnO3 and CaMnO3 as selective redox catalysts for efficient production of light olefins from naphtha via the ROC process. DA - 2019/6/5/ PY - 2019/6/5/ DO - 10.1016/j.apcatb.2019.01.048 VL - 246 SP - 30-40 SN - 1873-3883 UR - https://doi.org/10.1016/j.apcatb.2019.01.048 KW - Oxidative cracking KW - Naphtha KW - Chemical looping KW - Redox catalyst KW - Perovskite ER - TY - JOUR TI - Spectroscopic and Rheological Cross-Analysis of Polyester Polyol Cure Behavior: Role of Polyester Secondary Hydroxyl Content AU - Tilly, Joseph C. AU - Pervaje, Amulya K. AU - Inglefield, David L. AU - Santiso, Erik E. AU - Spontak, Richard J. AU - Khan, Saad A. T2 - ACS OMEGA AB - The sol-gel transition of a series of polyester polyol resins possessing varied secondary hydroxyl content and reacted with a polymerized aliphatic isocyanate cross-linking agent is studied to elucidate the effect of molecular architecture on cure behavior. Dynamic rheology is utilized in conjunction with time-resolved variable-temperature Fourier-transform infrared spectroscopy to examine the relationship between chemical conversion and microstructural evolution as functions of both time and temperature. The onset of a percolated microstructure is identified for all resins, and apparent activation energies extracted from Arrhenius analyses of gelation and average reaction kinetics are found to depend on the secondary hydroxyl content in the polyester polyols. The similarity between these two activation energies is explored. Gel point suppression is observed in all the resin systems examined, resulting in significant deviations from the classical gelation theory of Flory and Stockmayer. The magnitude of these deviations depends on secondary hydroxyl content, and a qualitative model is proposed to explain the observed phenomena, which are consistent with results previously reported in the literature. DA - 2019/1// PY - 2019/1// DO - 10.1021/acsomega.8b02766 VL - 4 IS - 1 SP - 932-939 SN - 2470-1343 UR - https://doi.org/10.1021/acsomega.8b02766 ER - TY - JOUR TI - Investigation of the Corrosion Behavior of Atomic Layer Deposited Al2O3/TiO2 Nanolaminate Thin Films on Copper in 0.1 M NaCl AU - Fusco, Michael A. AU - Oldham, Christopher J. AU - Parsons, Gregory N. T2 - MATERIALS AB - Fifty nanometers of Al₂O₃ and TiO₂ nanolaminate thin films deposited by atomic layer deposition (ALD) were investigated for protection of copper in 0.1 M NaCl using electrochemical techniques. Coated samples showed increases in polarization resistance over uncoated copper, up to 12 MΩ-cm², as measured by impedance spectroscopy. Over a 72-h immersion period, impedance of the titania-heavy films was found to be the most stable, as the alumina films experienced degradation after less than 24 h, regardless of the presence of dissolved oxygen. A film comprised of alternating Al₂O₃ and TiO₂ layers of 5 nm each (referenced as ATx5), was determined to be the best corrosion barrier of the films tested based on impedance spectroscopy measurements over 72 h and equivalent circuit modeling. Dissolved oxygen had a minimal effect on ALD film stability, and increasing the deposition temperature from 150 °C to 250 °C, although useful for increasing film quality, was found to be counterproductive for long-term corrosion protection. Implications of ALD film aging and copper-based surface film formation during immersion and testing are also discussed briefly. The results presented here demonstrate the potential for ultra-thin corrosion barrier coatings, especially for high aspect ratios and component interiors, for which ALD is uniquely suited. DA - 2019/2/2/ PY - 2019/2/2/ DO - 10.3390/ma12040672 VL - 12 IS - 4 SP - SN - 1996-1944 UR - https://www.mdpi.com/1996-1944/12/4/672 KW - atomic layer deposition KW - corrosion protection KW - copper KW - aluminum oxide KW - titanium oxide KW - nanolaminate KW - electrochemical impedance spectroscopy KW - barrier coatings ER - TY - JOUR TI - Functional model for analysis of ALD nucleation and quantification of area-selective deposition AU - Parsons, Gregory N. T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Bottom-up chemical patterning, to additively form material only in desired locations, is becoming important to address scaling issues in semiconductor device manufacturing, catalytic material design, and other fields utilizing nanometer- and sub-nanometer-scaled material features. In some semiconductor device fabrication steps, chemically driven patterning by area-selective deposition (ASD) is beginning to supplant physical patterning by photolithography. To advance the field of ASD, more understanding is needed regarding mechanisms of thin film nucleation, particularly when nucleation proceeds where thin film deposition is not desired. To better understand thin film nucleation, this work describes a relatively simple analytical model with three adjustable input parameters that quantifies film growth initiation, island growth, and thickness evolution during area-selective atomic layer deposition (AS-ALD) and area-selective chemical vapor deposition. A definition is presented for chemical selectivity during film growth that depends on the extent of film coverage in the desired non-growth region. Fitting the model with experimental data gives quantitative output that allows the extent of selectivity to be compared for different ASD approaches studied in different labs, with data collected using a variety of analytical tools. Using several example published AS-ALD data sets, the article demonstrates how fitting the model to experimental data gives insight into different nucleation mechanisms for unwanted film growth during ASD. The author further describes how the model can be improved and expanded to encompass more complex film growth and nucleation mechanisms. DA - 2019/3// PY - 2019/3// DO - 10.1116/1.5054285 VL - 37 IS - 2 SP - SN - 1520-8559 UR - https://doi.org/10.1116/1.5054285 ER - TY - JOUR TI - Liquid metal-filled magnetorheological elastomer with positive piezoconductivity AU - Yun, Guolin AU - Tang, Shi-Yang AU - Sun, Shuaishuai AU - Yuan, Dan AU - Zhao, Qianbin AU - Deng, Lei AU - Yan, Sheng AU - Du, Haiping AU - Dickey, Michael D. AU - Li, Weihua T2 - Nature Communications AB - Abstract Conductive elastic composites have been used widely in soft electronics and soft robotics. These composites are typically a mixture of conductive fillers within elastomeric substrates. They can sense strain via changes in resistance resulting from separation of the fillers during elongation. Thus, most elastic composites exhibit a negative piezoconductive effect, i.e. the conductivity decreases under tensile strain. This property is undesirable for stretchable conductors since such composites may become less conductive during deformation. Here, we report a liquid metal-filled magnetorheological elastomer comprising a hybrid of fillers of liquid metal microdroplets and metallic magnetic microparticles. The composite’s resistivity reaches a maximum value in the relaxed state and drops drastically under any deformation, indicating that the composite exhibits an unconventional positive piezoconductive effect. We further investigate the magnetic field-responsive thermal properties of the composite and demonstrate several proof-of-concept applications. This composite has prospective applications in sensors, stretchable conductors, and responsive thermal interfaces. DA - 2019/3/21/ PY - 2019/3/21/ DO - 10.1038/s41467-019-09325-4 UR - https://doi.org/10.1038/s41467-019-09325-4 ER - TY - JOUR TI - Facile Room‐Temperature Anion Exchange Reactions of Inorganic Perovskite Quantum Dots Enabled by a Modular Microfluidic Platform AU - Abdel‐Latif, Kameel AU - Epps, Robert W. AU - Kerr, Corwin B. AU - Papa, Christopher M. AU - Castellano, Felix N. AU - Abolhasani, Milad T2 - Advanced Functional Materials AB - Abstract In an effort to produce the materials of next‐generation photoelectronic devices, postsynthesis halide exchange reactions of perovskite quantum dots are explored to achieve enhanced bandgap tunability. However, comprehensive understanding of the multifaceted halide exchange reactions is inhibited by their vast relevant parameter space and complex reaction network. In this work, a facile room‐temperature strategy is presented for rapid halide exchange of inorganic perovskite quantum dots. A comprehensive understanding of the halide exchange reactions is provided by isolating reaction kinetics from precursor mixing rates utilizing a modular microfluidic platform, Quantum Dot Exchanger (QDExer). The effects of ligand composition and halide salt source on the rate and extent of the halide exchange reactions are illustrated. This fluidic platform offers a unique time‐ and material‐efficient approach for studies of solution phase‐processed colloidal nanocrystals beyond those studied here and may accelerate the discovery and optimization of next‐generation materials for energy technologies. DA - 2019/6// PY - 2019/6// DO - 10.1002/adfm.201900712 UR - https://doi.org/10.1002/adfm.201900712 KW - anion exchange KW - continuous nanomanufacturing KW - in situ characterization KW - microfluidics KW - perovskite quantum dots ER - TY - JOUR TI - Publisher Correction: Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces AU - Esrafilzadeh, Dorna AU - Zavabeti, Ali AU - Jalili, Rouhollah AU - Atkin, Paul AU - Choi, Jaecheol AU - Carey, Benjamin J. AU - Brkljača, Robert AU - O’Mullane, Anthony P. AU - Dickey, Michael D. AU - Officer, David L. AU - MacFarlane, Douglas R. AU - Daeneke, Torben AU - Kalantar-Zadeh, Kourosh T2 - Nature Communications AB - The original version of this Article contained errors in the author affiliations. Affiliation 1 incorrectly read ‘School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW 2031, Australia’ and affiliation 4 incorrectly read ‘School of Engineering, RMIT University, Melbourne, VIC 3001, Australia.’ This has now been corrected in both the PDF and HTML versions of the Article. DA - 2019/3/20/ PY - 2019/3/20/ DO - 10.1038/s41467-019-09228-4 UR - https://doi.org/10.1038/s41467-019-09228-4 ER - TY - JOUR TI - Genome Editing with CRISPR-Cas9 in Lactobacillus plantarum Revealed That Editing Outcomes Can Vary Across Strains and Between Methods AU - Leenay, Ryan T. AU - Vento, Justin M. AU - Shah, Malay AU - Martino, Maria Elena AU - Leulier, Francois AU - Beisel, Chase L. T2 - BIOTECHNOLOGY JOURNAL AB - Lactic-acid bacteria such as Lactobacillus plantarum are commonly used for fermenting foods and as probiotics, where increasingly sophisticated genome-editing tools are employed to elucidate and enhance these microbes' beneficial properties. The most advanced tools to date utilize an oligonucleotide or double-stranded DNA donor for recombineering and Cas9 for targeted DNA cleavage. As the associated methods are often developed in isolation for one strain, it remains unclear how different Cas9-based editing methods compare across strains. Here, this work directly compares two methods in different strains of L. plantarum: one utilizing a plasmid-encoded recombineering template and another utilizing an oligonucleotide donor and an inducible DNA recombinase. This comparison reveals one instance in which only the recombineering-template method generates desired edits and another instance in which only the oligo method generates desired edits. It is further found that both methods exhibit highly variable success editing the same site across multiple L. plantarum strains. Finally, failure modes are identified for the recombineering-template method, including a consistent genomic deletion and reversion of a point mutation in the recombineering template. This study therefore highlights surprising differences for Cas9-mediated genome editing between methods and related strains, arguing for the need for multiple, distinct methods when performing CRISPR-based editing in bacteria. DA - 2019/3// PY - 2019/3// DO - 10.1002/biot.201700583 VL - 14 IS - 3 SP - SN - 1860-7314 KW - genome editing KW - lactobacilli KW - recombineering KW - shuttle plasmids ER - TY - JOUR TI - Continuous synthesis of elastomeric macroporous microbeads AU - Bennett, Jeffrey A. AU - Campbell, Zachary S. AU - Abolhasani, Milad T2 - REACTION CHEMISTRY & ENGINEERING AB - Macroporous microbeads are synthesized by microfluidic production of silica-loaded polymeric microdroplets followed by porogen removal via selective etching. DA - 2019/2/1/ PY - 2019/2/1/ DO - 10.1039/c8re00189h VL - 4 IS - 2 SP - 254-260 SN - 2058-9883 UR - https://doi.org/10.1039/C8RE00189H ER - TY - JOUR TI - Functional Liquid Metal Nanoparticles Produced by Liquid-Based Nebulization AU - Tang, Shi-Yang AU - Qiao, Ruirui AU - Lin, Yiliang AU - Li, Yuhuan AU - Zhao, Qianbin AU - Yuan, Dan AU - Yun, Guolin AU - Guo, Jinhong AU - Dickey, Michael D. AU - Huang, Tony Jun AU - Davis, Thomas P. AU - Kalantar-Zadeh, Kourosh AU - Li, Weihua T2 - ADVANCED MATERIALS TECHNOLOGIES AB - Abstract Functional liquid metal nanoparticles (NPs), produced from eutectic alloys of gallium, promise new horizons in the fields of sensors, microfluidics, flexible electronics, catalysis, and biomedicine. Here, the development of a vapor cavity generating ultrasonic platform for nebulizing liquid metal within aqueous media for the one‐step production of stable and functional liquid metal NPs is shown. The size distribution of the NPs is fully characterized and it is demonstrated that various macro and small molecules can also be grafted onto these liquid metal NPs during the liquid‐based nebulization process. The cytotoxicity of the NPs grafted with different molecules is further explored. Moreover, it is shown that it is possible to control the thickness of the oxide layer on the produced NPs using electrochemistry that can be embedded within the platform. It is envisaged that this platform can be adapted as a cost‐effective and versatile device for the rapid production of functional liquid metal NPs for future liquid metal‐based optical, electronic, catalytic, and biomedical applications. DA - 2019/2// PY - 2019/2// DO - 10.1002/admt.201800420 VL - 4 IS - 2 SP - SN - 2365-709X KW - EGaIn KW - functional material KW - liquid metal KW - nanoparticle KW - nebulization ER - TY - JOUR TI - Deep Learning Enables High-Throughput Analysis of Particle-Aggregation-Based Biosensors Imaged Using Holography AU - Wu, Yichen AU - Ray, Aniruddha AU - Wei, Qingshan AU - Feizi, Alborz AU - Tong, Xin AU - Chen, Eva AU - Luo, Yi AU - Ozcan, Aydogan T2 - ACS PHOTONICS AB - Aggregation-based assays, using micro- and nanoparticles have been widely accepted as an efficient and cost-effective biosensing tool, particularly in microbiology, where particle clustering events are used as a metric to infer the presence of a specific target analyte and quantify its concentration. Here, we present a sensitive and automated readout method for aggregation-based assays using a wide-field lens-free on-chip microscope, with the ability to rapidly analyze and quantify microscopic particle aggregation events in 3D, using deep learning-based holographic image reconstruction. In this method, the computation time for hologram reconstruction and particle autofocusing steps remains constant, regardless of the number of particles/clusters within the 3D sample volume, which provides a major throughput advantage, brought by deep learning-based image reconstruction. As a proof of concept, we demonstrate rapid detection of herpes simplex virus (HSV) by monitoring the clustering of antibody-coated microparticles, achieving a detection limit of ∼5 viral copies/μL (i.e., ∼25 copies/test). DA - 2019/2// PY - 2019/2// DO - 10.1021/acsphotonics.8b01479 VL - 6 IS - 2 SP - 294-301 SN - 2330-4022 UR - https://doi.org/10.1021/acsphotonics.8b01479 KW - particle clustering assay KW - biosensing KW - virus sensing KW - deep learning KW - digital holography KW - computational microscopy ER - TY - JOUR TI - Effect of micro-roughness shapes on jet impingement heat transfer and fin-effectiveness AU - Singh, Prashant AU - Zhang, Mingyang AU - Ahmed, Shoaib AU - Ramakrishnan, Kishore R. AU - Ekkad, Srinath T2 - INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER AB - With recent advancements in the field of additive manufacturing, the design domain for development of complicated cooling configurations has significantly expanded. The motivation of the present study is to develop high performance impingement cooling designs catered towards applications requiring high rates of heat removal, e.g. gas turbine blade leading edge and double-wall cooling, air-cooled electronic devices, etc. In the present study, jet impingement is combined with strategic roughening of the target surface, to achieve high heat removal rates. Steady state experiments have been carried out to calculate the heat transfer coefficient for jet impingement onto different target surface configurations. The jet-to-jet spacing (x/d = y/d) was varied from 2 to 5, and jet-to-target distance (z/d) was varied from 1 to 5. The target surface configurations featured cylindrical, cubic and concentric shaped roughness elements, fabricated through binder jetting process. The baseline case for the roughened target surface was a smooth target. Heat transfer and pressure drop experiments were carried out at Reynolds numbers ranging from 2500 to 10,000. Further, numerical simulations were carried out to model flow and heat transfer for all configurations at a representative Reynolds number. Through our experiments and numerical results, we have demonstrated that the novel “concentric” roughness shape was the best in terms of fin effectiveness and Nusselt numbers levels, amongst the investigated shapes. The concentric-shape roughened target resulted in fin effectiveness up to 1.6, whereas the cubic- and cylindrical-shape roughened targets yielded in fin effectiveness up to 1.4 and 1.3, respectively. Further, it was experimentally found that the addition of micro-roughness elements does not result in a discernable increment in pressure losses, compared to the impingement on the smooth target surface. Hence, the demonstrated configuration with the highest heat transfer coefficient also resulted in highest thermal hydraulic performance. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.ijheatmasstransfer.2018.11.135 VL - 132 SP - 80-95 SN - 1879-2189 KW - Convective heat transfer KW - Pin fins KW - Jet impingement KW - Fin effectiveness KW - Thermal hydraulic performance ER - TY - JOUR TI - Thermally driven directional free-radical polymerization in confined channels AU - Datta, Preeta AU - Efimenko, Kirill AU - Genzer, Jan T2 - POLYMER CHEMISTRY AB - We report on the formation of poly(acrylamide) (PAAm) with a relatively-narrow molecular weight distribution (MWD) by means of thermally-driven directional free-radical polymerization carried out in polymerization chambers featuring two parallel glass walls separated by various distances, ranging from sub-millimeter to a few millimeters. DA - 2019/2/28/ PY - 2019/2/28/ DO - 10.1039/c8py01550c VL - 10 IS - 8 SP - 920-925 SN - 1759-9962 UR - https://doi.org/10.1039/C8PY01550C ER - TY - JOUR TI - Optimization of Sequence, Display, and Mode of Operation of IgG-Binding Peptide Ligands to Develop Robust, High-Capacity Affinity Adsorbents That Afford High IgG Product Quality AU - Islam, Tuhidul AU - Naik, Amith D. AU - Hashimoto, Yasuhiro AU - Menegatti, Stefano AU - Carbonell, Ruben G. T2 - INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES AB - This work presents the use of peptide ligand HWRGWV and its cognate sequences to develop affinity adsorbents that compete with Protein A in terms of binding capacity and quality of the eluted product. First, the peptide ligand was conjugated to crosslinked agarose resins (WorkBeads) at different densities and using different spacer arms. The optimization of ligand density and display resulted in values of static and dynamic binding capacity of 85 mg/mL and 65 mg/mL, respectively. A selected peptide-WorkBeads adsorbent was utilized for purifying Mabs from Chinese Hamster Ovary (CHO) cell culture supernatants. The peptide-WorkBeads adsorbent was found able to withstand sanitization with strong alkaline solutions (0.5 M NaOH). The purity of the eluted product was consistently higher than 95%, with logarithmic removal value (LRV) of 1.5 for host cell proteins (HCPs) and 4.0 for DNA. HCP clearance was significantly improved by adding a post-load washing step with either 0.1 M Tris HCl pH 9 or 1 M NaCl. The cognate peptide of HWRGWV, constructed by replacing arginine (R) with citrulline, further increased the HCP LRV to 2.15. The peptide-based adsorbent also showed a remarkable performance in terms of removal of Mab aggregates; unlike Protein A, in fact, HWRGWV was found to bind only monomeric IgG. Collectively, these results demonstrate the potential of peptide-based adsorbents as alternative to Protein A for the purification of therapeutic antibodies. DA - 2019/1/1/ PY - 2019/1/1/ DO - 10.3390/ijms20010161 VL - 20 IS - 1 SP - SN - 1422-0067 KW - affinity chromatography KW - peptide ligand KW - antibody purification KW - binding capacity KW - process optimization KW - aggregate removal ER - TY - JOUR TI - Extremely Thermoacidophilic Metallosphaera Species Mediate Mobilization and Oxidation of Vanadium and Molybdenum Oxides AU - Wheaton, Garrett H. AU - Vitko, Nicholas P. AU - Counts, James A. AU - Dulkis, Jessica A. AU - Podolsky, Igor AU - Mukherjee, Arpan AU - Kelly, Robert M. T2 - APPLIED AND ENVIRONMENTAL MICROBIOLOGY AB - Certain species from the extremely thermoacidophilic genus Metallosphaera directly oxidize Fe(II) to Fe(III), which in turn catalyzes abiotic solubilization of copper from chalcopyrite to facilitate recovery of this valuable metal. In this process, the redox status of copper does not change as it is mobilized. Metallosphaera species can also catalyze the release of metals from ores with a change in the metal's redox state. For example, Metallosphaera sedula catalyzes the mobilization of uranium from the solid oxide U3O8, concomitant with the generation of soluble U(VI). Here, the mobilization of metals from solid oxides (V2O3, Cu2O, FeO, MnO, CoO, SnO, MoO2, Cr2O3, Ti2O3, and Rh2O3) was examined for M. sedula and M. prunae at 70°C and pH 2.0. Of these oxides, only V and Mo were solubilized, a process accelerated in the presence of FeCl3 However, it was not clear whether the solubilization and oxidation of these metals could be attributed entirely to an Fe-mediated indirect mechanism. Transcriptomic analysis for growth on molybdenum and vanadium oxides revealed transcriptional patterns not previously observed for growth on other energetic substrates (i.e., iron, chalcopyrite, organic compounds, reduced sulfur compounds, and molecular hydrogen). Of particular interest was the upregulation of Msed_1191, which encodes a Rieske cytochrome b6 fusion protein (Rcbf, referred to here as V/MoxA) that was not transcriptomically responsive during iron biooxidation. These results suggest that direct oxidation of V and Mo occurs, in addition to Fe-mediated oxidation, such that both direct and indirect mechanisms are involved in the mobilization of redox-active metals by Metallosphaera species.IMPORTANCE In order to effectively leverage extremely thermoacidophilic archaea for the microbially based solubilization of solid-phase metal substrates (e.g., sulfides and oxides), understanding the mechanisms by which these archaea solubilize metals is important. Physiological analysis of Metallosphaera species growth in the presence of molybdenum and vanadium oxides revealed an indirect mode of metal mobilization, catalyzed by iron cycling. However, since the mobilized metals exist in more than one oxidation state, they could potentially serve directly as energetic substrates. Transcriptomic response to molybdenum and vanadium oxides provided evidence for new biomolecules participating in direct metal biooxidation. The findings expand the knowledge on the physiological versatility of these extremely thermoacidophilic archaea. DA - 2019/3// PY - 2019/3// DO - 10.1128/AEM.02805-18 VL - 85 IS - 5 SP - SN - 1098-5336 KW - Metallosphaera KW - biomining KW - extreme thermoacidophily KW - metal biooxidation KW - molybdenum KW - vanadium ER - TY - JOUR TI - Treating Tumors at Low Drug Doses Using an Aptamer-Peptide Synergistic Drug Conjugate AU - Pusuluri, Anusha AU - Krishnan, Vinu AU - Lensch, Valerie AU - Sarode, Apoorva AU - Bunyan, Elaine AU - Vogus, Douglas R. AU - Menegatti, Stefano AU - Soh, H. Tom AU - Mitragotri, Samir T2 - ANGEWANDTE CHEMIE-INTERNATIONAL EDITION AB - Abstract Combination chemotherapy must strike a difficult balance between safety and efficacy. Current regimens suffer from poor therapeutic impact because drugs are given at their maximum tolerated dose (MTD), which compounds the toxicity risk and exposes tumors to non‐optimal drug ratios. A modular framework has been developed that selectively delivers drug combinations at synergistic ratios via tumor‐targeting aptamers for effective low‐dose treatment. A nucleolin‐recognizing aptamer was coupled to peptide scaffolds laden with precise ratios of doxorubicin (DOX) and camptothecin (CPT). This construct had an extremely low IC 50 (31.9 n m ) against MDA‐MB‐231 breast cancer cells in vitro, and exhibited in vivo efficacy at micro‐dose injections (500 and 350 μg kg −1 dose −1 of DOX and CPT, respectively) that are 20–30‐fold lower than their previously‐reported MTDs. This approach represents a generalizable strategy for the safe and consistent delivery of combination drugs in oncology. DA - 2019/1/28/ PY - 2019/1/28/ DO - 10.1002/anie.201812650 VL - 58 IS - 5 SP - 1437-1441 SN - 1521-3773 KW - aptamer-drug conjugate KW - cancer KW - peptide scaffolds KW - synergy KW - targeted drug-delivery ER - TY - JOUR TI - Oxygen Vacancy Creation Energy in Mn-Containing Perovskites: An Effective Indicator for Chemical Looping with Oxygen Uncoupling AU - Mishra, Amit AU - Li, Tianyang AU - Li, Fanxing AU - Santiso, Erik E. T2 - CHEMISTRY OF MATERIALS AB - Chemical looping with oxygen uncoupling (CLOU) is a novel process for carbon dioxide capture from coal combustion. Designing a metal oxide oxygen carrier with suitable oxygen release and uptake (redox) properties represents one of the most critical aspects for CLOU. The current work aims to correlate oxygen vacancy creation energy of metal oxide oxygen carriers with their redox properties. Oxygen vacancy creation energies of CaMnO3−δ, Ca0.75Sr0.25MnO3−δ, CaMn0.75Fe0.25O3−δ, and BaMnO3−δ were determined through density functional theory (DFT) calculations. The effect of the Hubbard U correction on the ground state magnetic configurations and vacancy creation energies was investigated, along with the effect of lattice oxygen coordination environment. It was determined that Hubbard U only slightly changes the relative differences in vacancy creation energies between the Mn-containing perovskites investigated. Therefore, ranking of oxygen vacancy creation energies among the various oxides can be determined using a simplified method without using Hubbard U. Comparisons with experimental data confirmed that vacancy creation energy is an effective indicator for oxygen release properties of the perovskites investigated: oxygen carrier materials with lower vacancy creation energies can release their lattice oxygen more readily. Thermogravimetric analysis indicated increased oxygen release with decreasing oxygen vacancy creation energy at temperatures below 700 °C. Higher activities for coal char combustion were also observed. The simplified DFT strategy also satisfactorily predicted the effects of iron and strontium doping on lattice distortions as well as the crystal volume changes upon oxygen vacancy creation. These findings indicate that oxygen vacancy creation energies in Mn-containing perovskites can potentially be used as an effective design parameter for oxygen carrier development and optimizations. DA - 2019/2/12/ PY - 2019/2/12/ DO - 10.1021/acs.chemmater.8b03187 VL - 31 IS - 3 SP - 689-698 SN - 1520-5002 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85061650487&partnerID=MN8TOARS ER - TY - JOUR TI - Dielectric and Resistive Heating of Polymeric Media: Toward Remote Thermal Activation of Stimuli-Responsive Soft Materials AU - Armstrong, Daniel P. AU - Spontak, Richard J. T2 - MACROMOLECULAR RAPID COMMUNICATIONS AB - Abstract Stimuli‐responsive soft materials are becoming increasingly important in a wide range of contemporary technologies, and methods by which to promote thermal stimulation remotely are of considerable interest for controllable device deployment, particularly in inaccessible environments such as outer space. Until now, remote thermal stimulation of responsive polymers has relied extensively on the use of nanocomposites wherein embedded nanoparticles/structures are selectively targeted for heating purposes. In this study, an alternative remote‐heating mechanism demonstrates that the dielectric and resistive thermal losses introduced upon application of an alternating current generate sufficient heat to raise the temperature of a neat polyimide by over 70 °C within ≈10 s. Thermal imaging is used here to measure current‐induced temperature changes of polymeric media, and a proposed analytical model yields predictions that compare reasonably well with experimental data, confirming that such remote heating is viable. Conditions permitting a shape‐memory polymer possessing a melting transition and susceptible to dielectric actuation to achieve continuous electrostrain‐temperature cycling are identified. DA - 2019/2// PY - 2019/2// DO - 10.1002/marc.201800669 VL - 40 IS - 4 SP - SN - 1521-3927 KW - dielectric heating KW - remote heating KW - shape-memory polymers KW - stimuli responsive KW - thermal activation ER - TY - JOUR TI - Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces AU - Esrafilzadeh, Dorna AU - Zavabeti, Ali AU - Jalili, Rouhollah AU - Atkin, Paul AU - Choi, Jaecheol AU - Carey, Benjamin J. AU - Brkljača, Robert AU - O’Mullane, Anthony P. AU - Dickey, Michael D. AU - Officer, David L. AU - MacFarlane, Douglas R. AU - Daeneke, Torben AU - Kalantar-Zadeh, Kourosh T2 - Nature Communications AB - Negative carbon emission technologies are critical for ensuring a future stable climate. However, the gaseous state of CO2 does render the indefinite storage of this greenhouse gas challenging. Herein, we created a liquid metal electrocatalyst that contains metallic elemental cerium nanoparticles, which facilitates the electrochemical reduction of CO2 to layered solid carbonaceous species, at a low onset potential of -310 mV vs CO2/C. We exploited the formation of a cerium oxide catalyst at the liquid metal/electrolyte interface, which together with cerium nanoparticles, promoted the room temperature reduction of CO2. Due to the inhibition of van der Waals adhesion at the liquid interface, the electrode was remarkably resistant to deactivation via coking caused by solid carbonaceous species. The as-produced solid carbonaceous materials could be utilised for the fabrication of high-performance capacitor electrodes. Overall, this liquid metal enabled electrocatalytic process at room temperature may result in a viable negative emission technology. DA - 2019/2/26/ PY - 2019/2/26/ DO - 10.1038/s41467-019-08824-8 UR - https://doi.org/10.1038/s41467-019-08824-8 ER - TY - JOUR TI - Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis AU - Mineart, Kenneth P. AU - Ryan, Justin J. AU - Appavou, Marie-Sousai AU - Lee, Byeongdu AU - Gradzielski, Michael AU - Spontak, Richard J. T2 - LANGMUIR AB - Ionic, and specifically sulfonated, block copolymers are continually gaining interest in the soft materials community due to their unique suitability in various ion-exchange applications such as fuel cells, organic photovoltaics, and desalination membranes. One unresolved challenge inherent to these materials is solvent templating, that is, the translation of self-assembled solution structures into nonequilibrium solid film morphologies. Recently, the use of mixed polar/nonpolar organic solvents has been examined in an effort to elucidate and control the solution self-assembly of sulfonated block copolymers. The current study sheds new light on micellar assemblies (i.e., those with the sulfonated blocks comprising the micellar core) of a midblock-sulfonated pentablock copolymer in polar/nonpolar solvent mixtures by combining small-angle X-ray and small-angle neutron scattering. Our scattering data reveal that micelle size depends strongly on overall solvent composition: micelle cores and coronae grow as the fraction of nonpolar solvent is increased. Universal model fits further indicate that an unexpectedly high fraction of the micelle cores is occupied by polar solvent (60–80 vol %) and that partitioning of the polar solvent into micelle cores becomes more pronounced as its overall quantity decreases. This solvent presence in the micelle cores explains the simultaneous core/corona growth, which is otherwise counterintuitive. Our findings provide a potential pathway for the formation of solvent-templated films with more interconnected morphologies due to the greatly solvated micellar cores in solution, thereby enhancing the molecular, ion, and electron-transport properties of the resultant films. DA - 2019/1/29/ PY - 2019/1/29/ DO - 10.1021/acs.langmuir.8b03825 VL - 35 IS - 4 SP - 1032-1039 SN - 0743-7463 ER - TY - JOUR TI - Hybrid Carbon Nanotube Fabrics with Sacrificial Nanofibers for Flexible High Performance Lithium-Ion Battery Anodes AU - Yildiz, Ozkan AU - Dirican, Mahmut AU - Fang, Xiaomeng AU - Fu, Kun AU - Jia, Hao AU - Stano, Kelly AU - Zhang, Xiangwu AU - Bradford, Philip D. T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - Silicon is one of the most promising anode materials for lithium-ion batteries because of its highest known theoretical charge capacity (4,200 mAh g−1). However, it has found limited application in commercial batteries because of the significant volume change (up to 400%) of silicon during cycling, which results in pulverization and capacity fading. Here, we present a new method to develop a silicon - carbon nanotube (CNT) hybrid anode architecture using CNT-polymer nanofiber hybridization method. The anode material is produced by electrospinning PMMA-Si nanofibers onto aligned CNT sheets, which are drawn on a grounded, rotating take-up roller, and then subsequently decomposing the PMMA electrospun fibers at elevated temperature to create a uniform distribution of Si particles within the CNT sheets. The whole structure is then coated with pyrolytic carbon via chemical vapor deposition (CVD). The architecture provides sufficient space to accommodate the volume expansion of the Si nanoparticles. The CVD pyrolytic carbon coating helps to anchor the Si nanoparticles within CNT sheets and stabilize solid-electrolyte-interface (SEI) formation. The novel freestanding, binder free CNT-Si-C sheet hybrid exhibited improved performance in terms of excellent cycling capacity (1470 mAh g−1), high coulombic efficiency (98%), and good capacity retention of 88% after 150 cycles. DA - 2019/2/9/ PY - 2019/2/9/ DO - 10.1149/2.0821902jes VL - 166 IS - 4 SP - A473-A479 SN - 1945-7111 UR - https://publons.com/publon/26924627/ ER - TY - JOUR TI - Toughening stretchable fibers via serial fracturing of a metallic core AU - Cooper, Christopher B. AU - Joshipura, Ishan D. AU - Parekh, Dishit P. AU - Norkett, Justin AU - Mailen, Russell AU - Miller, Victoria M. AU - Genzer, Jan AU - Dickey, Michael D. T2 - SCIENCE ADVANCES AB - Stretchable fibers dissipate energy via the sequential fracturing of a metallic core held together by an elastomeric shell. DA - 2019/2// PY - 2019/2// DO - 10.1126/sciadv.aat4600 VL - 5 IS - 2 SP - SN - 2375-2548 UR - https://doi.org/10.1126/sciadv.aat4600 ER - TY - JOUR TI - Thermodynamic phase diagram of amyloid-β (16–22) peptide AU - Wang, Yiming AU - Bunce, Samuel J. AU - Radford, Sheena E. AU - Wilson, Andrew J. AU - Auer, Stefan AU - Hall, Carol K. T2 - Proceedings of the National Academy of Sciences AB - Significance Phase diagrams of atomic systems are calculated routinely by computer simulations, but such calculations are absent for even the simplest peptides. Previous simulations are mainly nonequilibrium and focus on the assembly of peptides from the monomeric state to the aggregated state. To obtain accurate equilibrium solubilities, it is necessary to simulate many assembly and disassembly events of fibrillar aggregates, which is notoriously difficult as it requires breaking many hydrogen bonds. We overcome these challenges and calculate the equilibrium phase diagram of amyloid β protein (16–22) (Aβ 16–22 ), the archetypal amyloid former, using a realistic protein model. Importantly, our prediction of Aβ 16–22 solubility over temperatures from 277 to 330 K agrees well with experimental measurements. DA - 2019/2/5/ PY - 2019/2/5/ DO - 10.1073/pnas.1819592116 VL - 116 IS - 6 SP - 2091-2096 J2 - Proc Natl Acad Sci USA LA - en OP - SN - 0027-8424 1091-6490 UR - http://dx.doi.org/10.1073/pnas.1819592116 DB - Crossref KW - phase diagram KW - solubility KW - amyloid KW - protein aggregation KW - coarse-grained simulation ER - TY - JOUR TI - Comparative Biochemical and Structural Analysis of Novel Cellulose Binding Proteins (Tapirins) from Extremely Thermophilic Caldicellulosiruptor Species AU - Lee, Laura L. AU - Hart, William S. AU - Lunin, Vladimir V. AU - Alahuhta, Markus AU - Bomble, Yannick J. AU - Himmel, Michael E. AU - Blumer-Schuette, Sara E. AU - Adams, Michael W. W. AU - Kelly, Robert M. T2 - APPLIED AND ENVIRONMENTAL MICROBIOLOGY AB - Genomes of extremely thermophilic Caldicellulosiruptor species encode novel cellulose binding proteins, called tāpirins, located proximate to the type IV pilus locus. The C-terminal domain of Caldicellulosiruptor kronotskyensis tāpirin 0844 (Calkro_0844) is structurally unique and has a cellulose binding affinity akin to that seen with family 3 carbohydrate binding modules (CBM3s). Here, full-length and C-terminal versions of tāpirins from Caldicellulosiruptor bescii (Athe_1870), Caldicellulosiruptor hydrothermalis (Calhy_0908), Caldicellulosiruptor kristjanssonii (Calkr_0826), and Caldicellulosiruptor naganoensis (NA10_0869) were produced recombinantly in Escherichia coli and compared to Calkro_0844. All five tāpirins bound to microcrystalline cellulose, switchgrass, poplar, and filter paper but not to xylan. Densitometry analysis of bound protein fractions visualized by SDS-PAGE revealed that Calhy_0908 and Calkr_0826 (from weakly cellulolytic species) associated with the cellulose substrates to a greater extent than Athe_1870, Calkro_0844, and NA10_0869 (from strongly cellulolytic species). Perhaps this relates to their specific needs to capture glucans released from lignocellulose by cellulases produced in Caldicellulosiruptor communities. Calkro_0844 and NA10_0869 share a higher degree of amino acid sequence identity (>80% identity) with each other than either does with Athe_1870 (∼50%). The levels of amino acid sequence identity of Calhy_0908 and Calkr_0826 to Calkro_0844 were only 16% and 36%, respectively, although the three-dimensional structures of their C-terminal binding regions were closely related. Unlike the parent strain, C. bescii mutants lacking the tāpirin genes did not bind to cellulose following short-term incubation, suggesting a role in cell association with plant biomass. Given the scarcity of carbohydrates in neutral terrestrial hot springs, tāpirins likely help scavenge carbohydrates from lignocellulose to support growth and survival of Caldicellulosiruptor species.IMPORTANCE The mechanisms by which microorganisms attach to and degrade lignocellulose are important to understand if effective approaches for conversion of plant biomass into fuels and chemicals are to be developed. Caldicellulosiruptor species grow on carbohydrates from lignocellulose at elevated temperatures and have biotechnological significance for that reason. Novel cellulose binding proteins, called tāpirins, are involved in the way that Caldicellulosiruptor species interact with microcrystalline cellulose, and additional information about the diversity of these proteins across the genus, including binding affinity and three-dimensional structural comparisons, is provided here. DA - 2019/2// PY - 2019/2// DO - 10.1128/AEM.01983-18 VL - 85 IS - 3 SP - SN - 1098-5336 KW - Caldicellulosiruptor KW - cellulose binding protein KW - lignocellulose KW - tapirin ER - TY - JOUR TI - Graphene oxide model with desirable structural and chemical properties AU - Qiao, Qi AU - Liu, Chang AU - Gao, Wei AU - Huang, Liangliang T2 - CARBON AB - Due to unique chemical, electrical and optical properties, graphene oxide has been widely used as a promising candidate for many applications. Theoretical GO models developed so far present a good description of its chemical structure. However, when it comes to the structural properties, such as the size and distribution of vacancy defects, the curvature (or roughness), there exist significant gaps between computational models and experimentally synthesized GO materials. In this work, we carry out reactive molecular dynamics simulations and use experimental characteristics to fine tune theoretical GO models. Attentions have been paid to the vacancy defects, the distribution and hybridization of carbon atoms, and the overall C/O ratio of GO. The GO models proposed in this work have been significantly improved to represent quantitative structural details of GO materials synthesized via the modified Hummers method. The temperature-programmed protocol and the computational post analyses of Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, vacancy size and curvature distribution, are of general interest to a broad audience working on GO structures from other synthesis methods and other two-dimensional materials and their composites. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.carbon.2018.11.063 VL - 143 SP - 566-577 SN - 1873-3891 ER - TY - JOUR TI - All-silica zeolites screening for capture of toxic gases from molecular simulation AU - Yan, Zhiguo AU - Tang, Sai AU - Zhou, Xumiao AU - Yang, Li AU - Xiao, Xingqing AU - Chen, Houyang AU - Qin, Yuanhang AU - Sun, Wei T2 - CHINESE JOURNAL OF CHEMICAL ENGINEERING AB - The exhaust gases, including SO2, NH3, H2S, NO2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment. Zeolites have been considered as good absorbent candidates to capture the six exhaust gases. In this work, we performed grand canonical ensemble Monte Carlo (GCMC) simulations to examine the capability of 95 kinds of all-silica zeolites in the removal of the six toxic gases, and to predict the adsorption isotherms of the six gases on all the zeolites. The simulation results showed that, H2S, NO, NO2, CO and NH3 are well-captured by zeolite structures with accessible surface area of 1600–1800 m2·g− 1 and pore diameter of 0.6–0.7 nm, such as AFY and PAU, while SO2 is well-adsorbed by zeolites containing larger accessible surface area (1700–2700 m2·g− 1) and pore diameter (0.7–1.4 nm) at room temperature and an atmospheric pressure. However, at saturated adsorption, zeolites RWY, IRR, JSR, TSC, and ITT are found to exhibit better abilities to capture these gases. Our study provides useful computational insights in choosing and designing zeolite structures with high performance to remove toxic gases for air purification, thereby facilitating the development and application of exhaust gas-processing technology in green industry. DA - 2019/1// PY - 2019/1// DO - 10.1016/j.cjche.2018.02.025 VL - 27 IS - 1 SP - 174-181 SN - 2210-321X KW - All-silica zeolites KW - Toxic gases KW - Adsorption isotherm KW - GCMC simulation ER - TY - JOUR TI - Engineering Efficient Photon Upconversion in Semiconductor Heterostructures AU - Milleville, Christopher C. AU - Chen, Eric Y. AU - Lennon, Kyle R. AU - Cleveland, Jill M. AU - Kumar, Abinash AU - Zhang, Jing AU - Bork, James A. AU - Tessier, Ansel AU - LeBeau, James M. AU - Chase, D. Bruce AU - Zide, Joshua M. O. AU - Doty, Matthew F. T2 - ACS NANO AB - Photon upconversion is a photophysical process in which two low-energy photons are converted into one high-energy photon. Photon upconversion has broad appeal for a range of applications from biomedical imaging and targeted drug release to solar energy harvesting. Current upconversion nanosystems, including lanthanide-doped nanocrystals and triplet–triplet annihilation molecules, have achieved upconversion quantum yields on the order of 10–30%. However, the performance of these materials is hampered by inherently narrow absorption cross sections and fixed energy levels originating in atomic, ionic, or molecular states. Semiconductors, on the other hand, have inherently wide absorption cross sections. Moreover, recent advances enable the synthesis of colloidal semiconductor nanoparticles with complex heterostructures that can control band alignments and tune optical properties. We synthesize and characterize a three-component heterostructure that successfully upconverts photons under continuous-wave illumination and solar-relevant photon fluxes. The heterostructure is composed of two cadmium selenide quantum dots (QDs), an absorber and emitter, spatially separated by a cadmium sulfide nanorod (NR). We demonstrate that the principles of semiconductor heterostructure engineering can be applied to engineer improved upconversion efficiency. We first eliminate electron trap states near the surface of the absorbing QD and then tailor the band gap of the NR such that charge carriers are funneled to the emitting QD. When combined, these two changes result in a 100-fold improvement in photon upconversion performance. DA - 2019/1// PY - 2019/1// DO - 10.1021/acsnano.8b07062 VL - 13 IS - 1 SP - 489-497 SN - 1936-086X KW - solar energy KW - upconversion KW - nanostructures KW - semiconductors KW - core/rod/emitter coupled quantum dots ER - TY - JOUR TI - Flexible electrolyte-cathode bilayer framework with stabilized interface for room-temperature all-solid-state lithium-sulfur batteries AU - Zhu, Pei AU - Yan, Chaoyi AU - Zhu, Jiadeng AU - Zang, Jun AU - Jia, Hao AU - Dong, Xia AU - Du, Zhuang AU - Zhang, Chunming AU - Wu, Nianqiang AU - Dirican, Mahmut AU - Zhang, Xiangwu AU - Li, Ya T2 - ENERGY STORAGE MATERIALS AB - Lithium-sulfur batteries (LSBs) are promising next-generation energy storage system beyond state-of-the-art lithium-ion batteries because of their low cost and high energy density. However, liquid electrolyte-based LSBs suffer from “polysulfide shuttle”, and safety concerns originated from the use of flammable organic electrolytes and the formation of lithium dendrites. Herein, we report a novel bilayer framework through integrating a three-dimensional (3D) carbon nanofiber/sulfur (CNF/S) cathode with one-dimensional (1D) ceramic Li0.33La0.557TiO3 (LLTO) nanofiber-poly(ethylene oxide) (PEO) solid composite electrolyte to serve as both cathode and electrolyte for room-temperature ASSLSBs. The stabilized cycling performance of this novel bilayer structure design lies in the reduced interfacial resistance and enhanced electrode/electrolyte interfacial stability due to the addition of Li+ conducting 1D LLTO nanofibers, as well as the formed fast-continuous electron/ion transportation pathways within the 3D cathode architecture. Meanwhile, the mechanically robust bilayer framework with micro-/meso-pores could also accommodate the large volume change of sulfur during continuous charge-discharge process and help suppress the Li dendrite formation. As a result of the aforementioned benefits of the novel bilayer structure design, the introduced ASSLSBs could deliver a stable cycling performance at room temperature with high Coulombic efficiency of over 99%. DA - 2019/2// PY - 2019/2// DO - 10.1016/j.ensm.2018.11.009 VL - 17 SP - 220-225 SN - 2405-8297 UR - https://publons.com/publon/9539991/ KW - Composite solid electrolyte KW - All-solid-state batteries KW - Lithium-sulfur batteries KW - Lithium dendrite KW - Room temperature ER - TY - JOUR TI - Thermally Activated One-Pot, Simultaneous Radical and Condensation Reactions Generate Surface-Anchored Network Layers from Common Polymers AU - Pandiyarajan, C. K. AU - Genzer, Jan T2 - MACROMOLECULES AB - We present a versatile one-pot synthesis method that generates surface-attached polymer networks by cross-linking common polymers using thermally active 6-azidosulfonylhexyltriethoxysilane (6-ASHTES), which acts as a cross-linker and a surface-anchoring agent. We deposit a thin layer (∼200 nm) of a mixture comprising a given amount of 6-ASHTES and a polymer onto the substrate and anneal it at elevated temperatures (100–140 °C). Upon heating, the sulfonyl azide groups release nitrogen, and the resulting nitrenes abstract protons from the neighboring C–H bonds in polymers and undergo a C–H insertion reaction and/or recombination to form sulfonamide bonds. Condensation among ethoxysilane headgroups in bulk links 6-ASHTES units completes cross-linking. Simultaneously, 6-ASHTES reacts with substrate-bound −OH or C–H groups and attaches the covalently cross-linked polymer to the substrate. We carry out systematic investigation of gel kinetics involving annealing temperature, annealing time, and the concentration of 6-ASHTES for various polymer systems. This simple yet versatile approach involving simultaneous radical and condensation reactions adjusts the gel fraction in the polymer network and anchors the network to various substrates. DA - 2019/1/22/ PY - 2019/1/22/ DO - 10.1021/acs.macromol.8b02194 VL - 52 IS - 2 SP - 700-707 SN - 1520-5835 ER - TY - JOUR TI - Future scenarios of global plastic waste generation and disposal AU - Lebreton, Laurent AU - Andrady, Anthony T2 - PALGRAVE COMMUNICATIONS AB - Abstract The accumulation of mismanaged plastic waste (MPW) in the environment is a global growing concern. Knowing with precision where litter is generated is important to target priority areas for the implementation of mitigation policies. In this study, using country-level data on waste management combined with high-resolution distributions and long-term projections of population and the gross domestic product (GDP), we present projections of global MPW generation at ~1 km resolution from now to 2060. We estimated between 60 and 99 million metric tonnes (Mt) of MPW were produced globally in 2015. In a business-as-usual scenario, this figure could triple to 155–265 Mt y −1 by 2060. The future MPW load will continue to be disproportionately high in African and Asian continents even in the future years. However, we show that this growth in plastic waste can be reduced if developing economies significantly invest in waste management infrastructures as their GDP grows in the future and if efforts are made internationally to reduce the fraction of plastic in municipal solid waste. Using our projections, we also demonstrate that the majority of MPW (91%) are transported via watersheds larger than 100 km 2 suggesting that rivers are major pathways for plastic litter to the ocean. DA - 2019/1/29/ PY - 2019/1/29/ DO - 10.1057/s41599-018-0212-7 VL - 5 SP - SN - 2055-1045 ER - TY - JOUR TI - Development of a fused-sphere SAFT-gamma Mie force field for poly(vinyl alcohol) and poly(ethylene) AU - Walker, Christopher C. AU - Genzer, Jan AU - Santiso, Erik E. T2 - JOURNAL OF CHEMICAL PHYSICS AB - SAFT-γ Mie, a group-contribution equation of state rooted in Statistical Associating Fluid Theory, provides an efficient framework for developing accurate, transferable coarse-grained force fields for molecular simulation. Building on the success of SAFT-γ Mie force fields for small molecules, we address two key issues in extending the SAFT-γ Mie coarse-graining methodology to polymers: (1) the treatment of polymer chain rigidity and (2) the disparity between the structure of linear chains of tangent spheres and the structure of the real polymers. We use Boltzmann inversion to derive effective bond-stretching and angle-bending potentials mapped from all-atom oligomer molecular dynamics (MD) simulations to the coarse-grained sites and a fused-sphere version of SAFT-γ Mie as the basis for non-bonded interactions. The introduction of an overlap parameter between Mie spheres leads to a degeneracy when fitting to monomer vapor-liquid equilibria (VLE) data, which we resolve by matching polymer density from coarse-grained MD simulation with that from all-atom simulation. The result is a chain of monomers rigorously parameterized to experimental VLE data and with structural detail consistent with all-atom simulations. We test our approach on atactic poly(vinyl alcohol) and polyethylene and compare the results for SAFT-γ Mie models with structural detail mapped from the Optimized Potentials for Liquid Simulations (OPLS) and Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies (COMPASS) all-atom force fields. DA - 2019/1/21/ PY - 2019/1/21/ DO - 10.1063/1.5078742 VL - 150 IS - 3 SP - SN - 1089-7690 ER - TY - JOUR TI - Engineering Epigenetic Regulation Using Synthetic Read-Write Modules AU - Park, Minhee AU - Patel, Nikit AU - Keung, Albert J. AU - Khalil, Ahmad S. T2 - CELL AB - Chemical modifications to DNA and histone proteins are involved in epigenetic programs underlying cellular differentiation and development. Regulatory networks involving molecular writers and readers of chromatin marks are thought to control these programs. Guided by this common principle, we established an orthogonal epigenetic regulatory system in mammalian cells using N6-methyladenine (m6A), a DNA modification not commonly found in metazoan epigenomes. Our system utilizes synthetic factors that write and read m6A and consequently recruit transcriptional regulators to control reporter loci. Inspired by models of chromatin spreading and epigenetic inheritance, we used our system and mathematical models to construct regulatory circuits that induce m6A-dependent transcriptional states, promote their spatial propagation, and maintain epigenetic memory of the states. These minimal circuits were able to program epigenetic functions de novo, conceptually validating "read-write" architectures. This work provides a toolkit for investigating models of epigenetic regulation and encoding additional layers of epigenetic information in cells. DA - 2019/1/10/ PY - 2019/1/10/ DO - 10.1016/j.cell.2018.11.002 VL - 176 IS - 1-2 SP - 227-+ SN - 1097-4172 ER - TY - JOUR TI - Reversible Structure Formation of Aluminum Trihydroxide (ATH) Dispersions in Polydimethylsiloxane (PDMS) AU - Cox, Christopher J. AU - Hovey, Brentley AU - Fornes, Timothy D. AU - Khan, Saad A. T2 - LANGMUIR AB - Aluminum trihydroxide/polydimethylsiloxane (ATH/PDMS) systems are often used as potting compounds in electronic assemblies to guard the electronics from shock, vibration, corrosive agents, and moisture. In this study, we use dynamic rheology and confocal/optical microscopy to understand the dramatic effects miniscule levels of water have on the microstructure and corresponding rheological behavior of PDMS filled with ATH. In the absence of water, PDMS containing 20 wt % ATH readily flows, exhibiting viscoelastic behavior with some weak particle flocculation. However, the addition of only 0.045 wt % water to the system results in the formation of a sample-spanning, self-supporting physical gel that exhibits an elastic modulus ( G') five orders of magnitude higher than the water-free system. A structure formation mechanism consisting of hydration layer formation followed by interparticle water bridging has been proposed to explain the observed behavior. Recovery of the original viscoelastic fluid is demonstrated by adding molecular sieves (e.g., zeolites) to the fully flocculated system. The recovery can likely be attributed to the adsorption of water by the sieves and the corresponding breakup of water bridges between the ATH particles. On the basis of the proposed mechanism, a variety of other polar and nonpolar solvents have been found to induce physical gelation in ATH/PDMS dispersions with gel modulus being related to the Hildebrand solubility parameter mismatch between the solvent and PDMS fluid. DA - 2019/1/8/ PY - 2019/1/8/ DO - 10.1021/acs.langmuir.8b03577 VL - 35 IS - 1 SP - 237-247 SN - 0743-7463 UR - https://doi.org/10.1021/acs.langmuir.8b03577 ER - TY - JOUR TI - Monosaccharide Isomer Interconversions Become Significant at High Temperatures AU - McGill, Charles J. AU - Westmoreland, Phillip R. T2 - JOURNAL OF PHYSICAL CHEMISTRY A AB - Quantum-chemical calculations show how low barriers to anomerization and shifting equilibria cause a significant presence of different monosaccharide isomers in high-temperature processes such as pyrolysis. The transition between isomeric forms of monosaccharides is long-studied, but examination has typically been limited to the solution phase and to pyranose isomers. Processes and rates of anomerization by reversible, gas-phase ring-opening and -closing reactions were predicted for the monosaccharides d-glucose, d-mannose, d-galactose, d-xylose, l-arabinose, and d-glucuronic acid. Structures and thermochemistry were computed for stable species and pericyclic transition states using CBS-QB3, and high-pressure-limit Arrhenius reaction parameters were predicted and fitted from 300 to 1000 K. Activation energies for the ring-opening reactions were 162–217 kJ/mol for four-center pericyclic separation of the lactol group but were reduced by catalytic participation of a hydroxyl group within the monosaccharide or an external R–OH group represented by an explicit water molecule, reaching activation energies as low as 97 and 67 kJ/mol, respectively. Equilibrium constants implied increasing fractions of furanose and linear aldehyde anomers with increasing temperature. DA - 2019/1/10/ PY - 2019/1/10/ DO - 10.1021/acs.jpca.8b07217 VL - 123 IS - 1 SP - 120-131 SN - 1089-5639 ER - TY - JOUR TI - SnS hollow nanofibers as anode materials for sodium-ion batteries with high capacity and ultra-long cycling stability AU - Jia, Hao AU - Dirican, Mahmut AU - Sun, Na AU - Chen, Chen AU - Zhu, Pei AU - Yan, Chaoyi AU - Dong, Xia AU - Du, Zhuang AU - Guo, Jiansheng AU - Karaduman, Yekta AU - Wang, Jiasheng AU - Tang, Fangcheng AU - Tao, Jinsong AU - Zhang, Xiangwu T2 - CHEMICAL COMMUNICATIONS AB - In this study, a novel anode material of SnS hollow nanofibers (SnS HNFs) was rationally synthesized by a facile process and demonstrated to be a promising anode candidate for sodium-ion batteries. The synergetic effect of unique hollow and porous microstructures of SnS HNFs led to high capacity and ultra-long cycling stability. DA - 2019/1/14/ PY - 2019/1/14/ DO - 10.1039/c8cc07332e VL - 55 IS - 4 SP - 505-508 SN - 1364-548X UR - https://publons.com/publon/2973443/ ER - TY - JOUR TI - Hydrothermally synthesised NiCoP nanostructures and electrospun N-doped carbon nanofiber as multifunctional potential electrode for hybrid water electrolyser and supercapatteries AU - Surendran, Subramani AU - Shanmugapriya, Sathyanarayanan AU - Zhu, Pei AU - Yan, Chaoyi AU - Vignesh, Ramasamy Hari AU - Lee, Yun Sung AU - Zhang, Xiangwu AU - Selvan, Ramakrishnan Kalai T2 - ELECTROCHIMICA ACTA AB - In this work, a facile single-step hydrothermal technique is used to prepare a spherically concomitant foamy NiCoP as positrode for supercapatteries. Similarly, the nitrogen-doped carbon nanofibers are prepared by simple electrospinning technique to use as negatrode. The prepared materials are raptly examined through primary studies for both energy conversion and storage applications. Fascinatingly, NiCoP electrode encourages oxygen evolution reaction, and the carbon nanofiber electrode emboldens hydrogen evolution reaction with the minimum overpotential of 257 mV and 160 mV, respectively. In addition, a supercapattery is designed and operated at a full voltage window of 1.6 V using the fusion of carbon nanofiber as the negatrode and the cutting-edge NiCoP as the positrode, which presents a superior energy (56 Wh kg−1) and an improved power density (5333 W kg−1) with a long cyclic stability (5000 cycles). Finally, the fabricated supercapattery device is used to power the constructed hybrid water electrolyser that requisites a low cell voltage of 1.71 V to afford a current density of 10 mA cm−2. Overall, the prepared electrodes reveal its superiority of handling the multifunctional challenges for both water electrolyzer and supercapatteries. DA - 2019/2/10/ PY - 2019/2/10/ DO - 10.1016/j.electacta.2018.11.078 VL - 296 SP - 1083-1094 SN - 1873-3859 UR - https://publons.com/publon/21201014/ KW - Supercapattery KW - Water electrolyzer KW - Electrospinning KW - Phosphides KW - Carbon nanofiber ER - TY - JOUR TI - Reaction of phenol with singlet oxygen AU - Al-Nu’airat, Jomana AU - Dlugogorski, Bogdan Z. AU - Gao, Xiangpeng AU - Zeinali, Nassim AU - Skut, Jakub AU - Westmoreland, Phillip R. AU - Oluwoye, Ibukun AU - Altarawneh, Mohammednoor T2 - Physical Chemistry Chemical Physics AB - Photo-degradation of organic pollutants plays an important role in their removal from the environment. This study provides an experimental and theoretical account of the reaction of singlet oxygen O2(1Δg) with the biodegradable-resistant species of phenol in an aqueous medium. The experiments combine customised LED-photoreactors, high-performance liquid chromatography (HPLC), and electron paramagnetic resonance (EPR) imaging, employing rose bengal as a sensitiser. Guided by density functional theory (DFT) calculations at the M062X level, we report the mechanism of the reaction and its kinetic model. Addition of O2(1Δg) to the phenol molecule branches into two competitive 1,4-cycloaddition and ortho ene-type routes, yielding 2,3-dioxabicyclo[2.2.2]octa-5,7-dien-1-ol (i.e., 1,4-endoperoxide 1-hydroxy-2,5-cyclohexadiene) and 2-hydroperoxycyclohexa-3,5-dien-1-one, respectively. Unimolecular rearrangements of the 1,4-endoperoxide proceed in a facile exothermic reaction to form the only experimentally detected product, para-benzoquinone. EPR revealed the nature of the oxidation intermediates and corroborated the appearance of O2(1Δg) as the only active radical participating in the photosensitised reaction. Additional experiments excluded the formation of hydroxyl (HO˙), hydroperoxyl (HO2˙), and phenoxy intermediates. We detected for the first time the para-semibenzoquinone anion (PSBQ), supporting the reaction pathway leading to the formation of para-benzoquinone. Our experiments and the water-solvation model result in the overall reaction rates of kr-solvation = 1.21 × 104 M-1 s-1 and kr = 1.14 × 104 M-1 s-1, respectively. These results have practical application to quantify the degradation of phenol in wastewater treatment. DA - 2019/// PY - 2019/// DO - 10.1039/c8cp04852e VL - 21 IS - 1 SP - 171-183 J2 - Phys. Chem. Chem. Phys. LA - en OP - SN - 1463-9076 1463-9084 UR - http://dx.doi.org/10.1039/c8cp04852e DB - Crossref ER - TY - JOUR TI - Carbon-enhanced centrifugally-spun SnSb/carbon microfiber composite as advanced anode material for sodium-ion battery AU - Jia, Hao AU - Dirican, Mahmut AU - Aksu, Cemile AU - Sun, Na AU - Chen, Chen AU - Zhu, Jiadeng AU - Zhu, Pei AU - Yan, Chaoyi AU - Li, Ya AU - Ge, Yeqian AU - Guo, Jiansheng AU - Zhang, Xiangwu T2 - JOURNAL OF COLLOID AND INTERFACE SCIENCE AB - Antimony tin (SnSb) based materials have become increasingly attractive as a potential anode material for sodium-ion batteries (SIBs) owing to their prominent merit of high capacity. However, cyclic stability and rate capability of SnSb anodes are currently hindered by their large volume change during repeated cycling, which results in severe capacity fading. Herein, we introduce carbon-coated centrifugally-spun [email protected] microfiber (CMF) composites as high-performance anodes for SIBs that can maintain their structural stability during repeated charge-discharge cycles. The centrifugal spinning method was performed to fabricate [email protected] due to its high speed, low cost, and large-scale fabrication features. More importantly, extra carbon coating by chemical vapor deposition (CVD) has been demonstrated as an effective method to improve the capacity retention and Coulombic efficiency of the [email protected] anode. Electrochemical test results indicated that the as-prepared [email protected]@C anode could deliver a large reversible capacity of 798 mA h∙g−1 at the 20th cycle as well as a high capacity retention of 86.8% and excellent Coulombic efficiency of 98.1% at the 100th cycle. It is, therefore, demonstrated that [email protected]@C composite is a promising anode material candidate for future high-performance SIBs. DA - 2019/2/15/ PY - 2019/2/15/ DO - 10.1016/j.jcis.2018.10.101 VL - 536 SP - 655-663 SN - 1095-7103 UR - https://publons.com/publon/26924626/ KW - Energy storage KW - Sodium-ion battery KW - Carbon microfibers KW - Antimony tin KW - Composite KW - Centrifugal spinning KW - CVD coating KW - Anode KW - Cycling stability KW - Capacity KW - Rate capability KW - Coulombic efficiency ER - TY - JOUR TI - Recent progress in polymer materials for advanced lithium-sulfur batteries AU - Zhu, Jiadeng AU - Zhu, Pei AU - Yan, Chaoyi AU - Dong, Xia AU - Zhang, Xiangwu T2 - Progress in Polymer Science AB - Polymers play essential roles in the research and development of rechargeable batteries, especially, lithium-sulfur (Li-S) batteries which have been considered as a promising candidate of the next-generation power supply mainly because of their high theoretical energy density (up to five-fold compared to state-of-the-art lithium-ion batteries). However, practical applications of Li-S batteries are mainly hindered by the insulating nature of sulfur and its intermediates, the polysulfide shuttle effect, and the formation and growth of lithium dendrites. Polymer materials play an important role in addressing these issues of Li-S batteries and their structures and functionalities can be manipulated to control the electrochemical performance of Li-S batteries (e.g., cylability, rate capability, lifespan, etc.). In this review, we concentrate on the recent development of various polymer materials for Li-S batteries. It starts with a brief introduction of the Li-S battery followed by its fundamental electrochemistry and challenges. Significant attention is then paid to the applications of various polymers in each component of Li-S batteries with a focus on the mechanisms behind their operation which are presented and further discussed from five perspectives: i) polymers in cathodes, ii) polymer electrolytes, iii) polymer interlayers, iv) polymer separators, and v) polymers for the lithium metal anode protection. The aim is to present a detailed review of the critical aspects related to the functional polymers that can be used as important resources for researchers working in a diverse range of fields dealing with Li-S batteries. Finally, conclusions and perspectives are presented. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.progpolymsci.2018.12.002 VL - 90 SP - 118-163 UR - https://doi.org/10.1016/j.progpolymsci.2018.12.002 KW - Polymers KW - Lithium-sulfur batteries KW - Cathodes KW - Electrolytes KW - Interlayers/separators KW - Lithium metal ER - TY - JOUR TI - Facile and solvent-free fabrication of PEG-based membranes with interpenetrating networks for CO2 separation AU - Deng, Jing AU - Dai, Zhongde AU - Yan, Jiaqi AU - Sandru, Marius AU - Sandru, Eugenia AU - Spontak, Richard J. AU - Deng, Liyuan T2 - JOURNAL OF MEMBRANE SCIENCE AB - For nearly two decades, membranes derived from polyethers have served as promising candidate materials for CO2 separation. Due to the inherent tendency of high-molecular-weight poly(ethylene oxide) (PEO) to crystallize and thus reduce its CO2 permeability, prior studies have focused on membranes produced from low-molecular-weight poly(ethylene glycol) (PEG). In this work, a novel series of cross-linked PEG-based membranes composed of interpenetrating polymer networks has been generated through the use of amine-terminated Jeffamine and multiple acrylate-functionalized cross-linkers in a facile, solvent-free, two-stage reaction. Evidence of cross-linked interpenetrating polymer networks formed by aza-Michael addition and acrylate polymerization is confirmed by real-time fourier-transform infrared spectroscopy. In addition, we systematically investigate the thermal stability, mechanical properties and water sorption of these multicomponent membranes. Corresponding CO2 and N2 transport properties, evaluated by single-gas permeation tests, are found to depend on both the chemical nature of the cross-linkers and the ratio of the interpenetrating networks. Moreover, free PEG dimethyl ether has been added into the optimized cross-linked matrix at different loading levels to further enhance gas-transport properties. DA - 2019/1/15/ PY - 2019/1/15/ DO - 10.1016/j.memsci.2018.10.031 VL - 570 SP - 455-463 SN - 1873-3123 KW - Polymer cross-linking KW - Poly(ethylene glycol) KW - Interpenetrating networks KW - Aza-Michael addition KW - CO2 separation membrane ER - TY - JOUR TI - Kinetics of photocatalytic, self-cleaning surfaces: A decision tree approach for determination of reaction order AU - Ollis, David T2 - APPLIED CATALYSIS B-ENVIRONMENTAL AB - Self-cleaning photocatalytic surfaces have several decades of application, yet satisfactory rate equations for analyzing the kinetics of reactions on such solid surfaces are lacking, due in large part to the many configurations of the catalyst and the deposited contaminants. We analyze the existing literature and show that nearly all studies can be described by application of the power law for rate of reaction: Rate = kcat [C] n where n = apparent reaction order, and kcat is a fundamental constant of the catalytic material. The value of reaction order, n, we show requires answers to the following six questions. In each case, the observed apparent kinetic order depends upon interplay among the distributions of photocatalyst, reactant, and irradiance. 1. Is the photocatalyst porous or non-porous? Example: Stearic acid on/within non-porous/porous photocatalyst layer. 2. Is the photocatalytically active layer optically thin or thick? Example: Dye conversion in TiO2 layers vs. 10% TiO2/SiO2? 3. Is the probe reactant deposit a submonolayer or multilayer? Examples: Dye sub/multilayers with TiO2 4. Is probe reactant light absorption negligible or important? Example: Stearic acid vs. soot 5. Is the probe reactant present as a continuous film or as a distribution of discrete islands? Example: Long chain carboxylic acids on TiO2 6. If distributed, what is breadth of distribution? Example: Stearic acid on TiO2 For contaminant removal we demonstrate apparent reaction orders of 0, ½, 1, and 2! Simple analysis is used to explain this diversity of apparent reaction orders. We use the six questions posed to construct a decision tree for determination of the apparent reaction order, n, as a function of responses to the six questions. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.apcatb.2018.08.079 VL - 242 SP - 431-440 SN - 1873-3883 KW - Photocatalyst KW - Self-cleaning KW - Kinetics KW - Power law KW - Decision table ER - TY - JOUR TI - Composite solid electrolytes for all-solid-state lithium batteries AU - Dirican, Mahmut AU - Yan, Chaoyi AU - Zhu, Pei AU - Zhang, Xiangwu T2 - Materials Science and Engineering: R: Reports AB - Compared to currently used liquid-electrolyte lithium batteries, all-solid-state lithium batteries are safer and possess longer cycle life and have less requirements on packaging and state-of-charge monitoring circuits. Among various types of solid electrolytes, composite solid electrolytes, which are composed of active or passive inorganic fillers and polymer matrices, have been considered as promising electrolyte candidates for all-solid-state lithium batteries. Incorporation of inorganic fillers into the polymer matrices has been demonstrated as an effective method to achieve high ionic conductivity and excellent interfacial contact with the electrodes. In this review article, we first summarize the historical development of composite solid electrolytes. Contribution of both inert inorganic fillers and active Li-ion conductors to the ionic conductivity, electrochemical stability, and mechanical properties of the composite solid electrolytes are elaborated. Possible mechanisms of conductivity enhancement by inorganic fillers are broadly discussed. Examples of different composite solid electrolyte design concepts, such as inorganic nanoparticle/polymer, inorganic nanofiber/polymer, and other inorganic/polymer composite solid electrolytes, are introduced and their advantages and disadvantages are discussed. Inorganic filler/polymer composite solid electrolytes studied for use in various Li battery systems including Li-ion, Li-sulfur, and Li-metal batteries are evaluated. Promising designs of composite solid electrolytes and cathode materials used in all-solid-state Li batteries are also introduced. Finally, future perspectives on current requirements of composite solid electrolyte technologies are highlighted. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.mser.2018.10.004 VL - 136 SP - 27-46 UR - https://doi.org/10.1016/j.mser.2018.10.004 KW - All-solid-state lithium battery KW - Composite solid electrolyte KW - Inorganic filler KW - Ionic conductivity ER -