TY - JOUR TI - Oxygen Reduction on TiO2-Coated Carbon Nanofibers Decorated with Graphene Platelets AU - McClure, Joshua P. AU - Devine, Christina AU - Loebl, Andrew AU - Jiang, Rongzhong AU - Chu, Deryn AU - Cuomo, Jerome AU - Parsons, Gregory AU - Fedkiw, Peter S. T2 - ECS Transactions AB - The oxygen reduction reaction (ORR) was studied on heat-treated electrospun polyacrylonitrile (PAN) nanofibers with and without iron (II) phthalocyanine using rotating ring disk electrode voltammetry. In an effort to mitigate loss of the active sites and increase durability, atomic layer deposition was used to coat the nanofibers with TiO2 thin films. The results show that Fe-containing heat-treated nanofibers and TiO2-coated Fe-containing nanofibers exhibit a ~4-electron reduction of O2 with low % H2O2 yields (~1-1.5 %). DA - 2013/3/15/ PY - 2013/3/15/ DO - 10.1149/05002.1791ecst VL - 50 IS - 2 SP - 1791-1800 J2 - ECS Trans. OP - SN - 1938-5862 1938-6737 UR - http://dx.doi.org/10.1149/05002.1791ecst DB - Crossref ER - TY - SOUND TI - Enhancing Student Creativity and Writing Skills Through Engineering Statistics AU - Cooper, M. DA - 2013/// PY - 2013/// M3 - Workshop ER - TY - SOUND TI - The TurnItIn.com Debate: Plagiarism Detection Software and Academic Integrity AU - Cooper, M. DA - 2013/// PY - 2013/// ER - TY - SOUND TI - Use of Plagiarism Screening Software in Engineering Courses AU - Cooper, M. DA - 2013/// PY - 2013/// M3 - Workshop ER - TY - JOUR TI - Microfluidics as a tool for C. elegans research. AU - San-Miguel, Adriana AU - Lu, Hang T2 - WormBook : the online review of C. elegans biology AB - Microfluidics has emerged as a set of powerful tools that have greatly advanced some areas of biological research, including research using C. elegans. The use of microfluidics has enabled many experiments that are otherwise impossible with conventional methods. Today there are many examples that demonstrate the main advantages of using microfluidics for C. elegans research, achieving precise environmental conditions and facilitating worm handling. Examples range from behavioral analysis under precise chemical or odor stimulation, locomotion studies in well-defined structural surroundings, and even long-term culture on chip. Moreover, microfluidics has enabled coupling worm handling and imaging thus facilitating genetic screens, optogenetic studies, and laser ablation experiments. In this article, we review some of the applications of microfluidics for C. elegans research and provide guides for the design, fabrication, and use of microfluidic devices for C. elegans research studies. DA - 2013/// PY - 2013/// DO - 10.1895/wormbook.1.162.1 SP - 1-19 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=MEDLINE&KeyUT=MEDLINE:24065448&KeyUID=MEDLINE:24065448 ER - TY - JOUR TI - Labeling Thiols on Proteins, Living Cells and Tissues with Enhanced Emission Induced by FRET AU - Yuan, Yue AU - Wang, Xijun AU - Mei, Bin AU - Zhang, Dongxin AU - Tang, Anming AU - An, Linna AU - He, Xiaoxiao AU - Jiang, Jun AU - Liang, Gaolin T2 - Scientific Reports AB - Using N-(2-Aminoethyl)maleimide-cysteine(StBu) (Mal-Cys) as a medium, protein thiols were converted into N-terminal cysteines. After a biocompatible condensation reaction between the N-terminal cysteine and fluorescent probe 2-cyanobenzothiazole-Gly-Gly-Gly-fluorescein isothiocyanate (CBT-GGG-FITC), a new fluorogenic structure Luciferin-GGG-FITC was obtained. The latter exhibits near one order of magnitude (7 folds) enhanced fluorescence emission compared to the precursor moiety due to fluorescence resonance energy transfer (FRET) effect between the newly formed luciferin structure and the FITC motif. Theoretical investigations revealed the underlying mechanism that satisfactorily explained the experimental results. With this method, enhanced fluorescence imaging of thiols on proteins, outer membranes of living cells, translocation of membrane proteins, and endothelial cell layers of small arteries was successfully achieved. DA - 2013/// PY - 2013/// DO - 10.1038/srep03523 VL - 3 IS - 1 ER - TY - JOUR TI - Multifunctional Fluorescent Probe for Sequential Detections of Glutathione and Caspase-3 in Vitro and in Cells AU - Huang, Rui AU - Wang, Xijun AU - Wang, Dingli AU - Liu, Fang AU - Mei, Bin AU - Tang, Anming AU - Jiang, Jun AU - Liang, Gaolin T2 - Analytical Chemistry AB - Herein, we report a new “On–On” strategy based on the assembly and disassembly of fluorescein isothiocyanate nanoparticles (FITC-NPs) for sequential detections of glutathione (GSH) and caspase-3 (Casp3) with a multifunctional fluorescent probe 1. Theoretical investigations revealed the underlying mechanism that satisfactorily explained experimental results of such consecutive enhancements of fluorescence. Using this probe, we also successfully imaged the Casp3 activity in apoptotic cells. DA - 2013/6// PY - 2013/6// DO - 10.1021/ac4014012 VL - 85 IS - 13 SP - 6203-6207 ER - TY - RPRT TI - Gas Delivery Devices and Associated Systems and Methods AU - Li, Fanxing AU - Hu, Weiwei AU - Liu, Yang AU - Wiltberger, Kelly AU - Peng, Haofan AU - Ferguson, Rachel DA - 2013/// PY - 2013/// M1 - US10023831B2 M3 - Patent SN - US10023831B2 ER - TY - JOUR TI - Iron oxide with facilitated O2- transport for facile fuel oxidation and CO2 capture in a chemical looping scheme AU - Galinsky, N.L. AU - Huang, Y. AU - Shafiefarhood, A. AU - Li, F. T2 - ACS Sustainable Chemistry and Engineering DA - 2013/// PY - 2013/// DO - 10.1021/sc300177 VL - 1 IS - 3 SP - 364-373 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84884212784&partnerID=MN8TOARS ER - TY - CONF TI - Development of Fe-Cu oxygen carriers for solid fuel gasification and hydrogen production AU - Galinsky, N. AU - He, F. AU - Li, F. C2 - 2013/// C3 - Engineering Sciences and Fundamentals 2013 - Core Programming Area at the 2013 AIChE Annual Meeting: Global Challenges for Engineering a Sustainable Future DA - 2013/// VL - 2 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84911890253&partnerID=MN8TOARS ER - TY - JOUR TI - Atomic Layer Deposition of High Performance Ultrathin TiO2 Blocking Layers for Dye-Sensitized Solar Cells AU - Kim, Do Han AU - Woodroof, Mariah AU - Lee, Kyoungmi AU - Parsons, Gregory N. T2 - ChemSusChem AB - Abstract Invited for this month′s cover is the group of Gregory Parsons at North Carolina State University. The image shows one cycle of TiO 2 atomic layer deposition (ALD), in which the sequential dosing and purging of TiCl 4 and H 2 O forms ultrathin and conformal TiO 2 films on rough FTO glass. Pinhole‐free ALD TiO 2 forms a blocking layer to impede electron–hole recombination at the FTO/electrolyte interface in dye‐sensitized solar cells. The ALD process allows discrete tuning of the blocking‐layer thickness to maximize performance improvement. Read the full text of the article at 10.1002/cssc.201300067 DA - 2013/6// PY - 2013/6// DO - 10.1002/CSSC.201300468 VL - 6 IS - 6 SP - 930–930 SN - 1864-5631 UR - http://dx.doi.org/10.1002/CSSC.201300468 ER - TY - JOUR TI - Cover Picture: Atomic Layer Deposition of High Performance Ultrathin TiO2Blocking Layers for Dye-Sensitized Solar Cells (ChemSusChem 6/2013) AU - Kim, Do Han AU - Woodroof, Mariah AU - Lee, Kyoungmi AU - Parsons, Gregory N. T2 - ChemSusChem AB - The Cover Image shows the sequential dosing and purging of TiCl4 and H2O in atomic layer deposition (ALD) through step-like pressure changes in an effort to saturate the surface of fluorine doped tin oxide (FTO) glass with each reactant. These ultra-thin and uniform ALD TiO2 films with thicknesses of only 5 nm form a blocking layer on the rough FTO surface to be used in dye-sensitized solar cells (see the report by Kim et al. on page 1014) as the yallow photogenerated electrons to move to the FTO side effectively, thus inhibiting the recombination with holes at the FTO/electrolyte interface. DA - 2013/6// PY - 2013/6// DO - 10.1002/CSSC.201390023 VL - 6 IS - 6 SP - 929-929 J2 - ChemSusChem LA - en OP - SN - 1864-5631 UR - http://dx.doi.org/10.1002/CSSC.201390023 DB - Crossref ER - TY - JOUR TI - Spectroscopic Detection of Medium Range Order in Hydrogenated Amorphous Silicon, a-Si(H): Applications in Photovolatics, Thin Film Transistors and Si-based Microelectronics AU - Lucovsky, G. AU - Parsons, G. AU - Zeller, D. AU - Wu, K. AU - Papas, B. AU - Whitten, J. AU - Lujan, R. AU - Street, R.A. T2 - Physics Procedia AB - Hydrogenated amorphous silicon, a-Si1-xHx, with ~ at.10% or x ~0.1±0.02, is used in photovoltaics (PV), and thin film transistors (TFT's). Amorphous Si (a-Si) thin films, thought to be free of H, are used as precursors for polycrystalline gate electrodes in microelectronics. PV and TFT alloys has been deposited by the glow discharge method (GD), remote plasma-enhanced chemical vapor deposition (RPECVD, and reactive magnetron sputtering (RMS) with bonded-H determined by deposition precursors and substrate temperatures. Two conditions are required for low Si dangling bond densities ~0.5 to 1x1016 cm−3: (i) a bonded monohydride, Si-H, concentration of ~10 at. % H, and (ii) a deposition, and/or a post-deposition anneal at ~240 °C to 300 °C. These reduce strain by introducing medium range order (MRO) as nano-meter scale aperiodically-assembled clusters. Si L2,3 X-ray absorption spectroscopy (XAS) has been used to confirm MRO extending beyond short-range order (SRO) of continuous random networks (CRN) through observation of ligand-field split d-state features. These are associated with symmetry-adapted linear combinations (SALCs) of atomic states forming molecular orbital valence bands. XAS and photoelectron spectroscopy (PES) studies have confirmed that a-Si used for microelectronic applications also has MRO as well. This is associated with a H-transfer reaction from an Si-H bond of the cluster into a Si-H-Si bonding arrangement on near-neighbor sites. MRO has also identified by other spectroscopic techniques: spectroscopic ellipsomentry (SE), and ultra-violet or X-ray photoemission spectroscopy (UPS or XPS). The same H-atom motion induced by absorption of sun-light is responsible for the Staebler-Wronski Effect (SWE); the generation of Si-atom dangling bonds that degrade PV performance. DA - 2013/// PY - 2013/// DO - 10.1016/J.PHPRO.2013.04.012 VL - 44 SP - 91-98 J2 - Physics Procedia LA - en OP - SN - 1875-3892 UR - http://dx.doi.org/10.1016/J.PHPRO.2013.04.012 DB - Crossref KW - hydrogenated amorphous Si KW - a-Si-H KW - photovoltaic applications KW - thin film transistors KW - fine grain polycrystalline Si KW - medium range order KW - ligand field splittings KW - X-ray absorption spectroscopy KW - photemission spectroscopy KW - Staebler-Wronski Effect ER - TY - CONF TI - Plastics and Sustainability AU - Andrady, A.L. T2 - 2nd Middle East Process Engineering Conference C2 - 2013/9/29/ CY - Bahrain International Exhibition and Conference Center, Kingdom of Bahrain DA - 2013/9/29/ PY - 2013/9/29/ ER - TY - JOUR TI - Chemical sensing using electrospun polymer/carbon nanotube composite nanofibers with printed-on electrodes AU - Han, Li AU - Andrady, Anthony L. AU - Ensor, David S. T2 - Sensors and Actuators B: Chemical AB - An integrated sensor system was developed using mats formed of electrospun polymer/single-walled carbon nanotube composite nanofibers combined with inter-digitated electrodes directly printed on the surface to detect volatile organic compounds. When the polymer in the fibers swells due to vapor adsorption, the carbon nanotubes separate from each other and increase electrical resistance of the material. The conductivity change of the composite-sensing material was monitored with a multi-meter when exposed to volatile organic compounds. The response to different vapors showed a linear relationship between resistance change and vapor concentration. We obtained both sensitivity and selectivity data on the sensor with several different vapor analytes – methanol is used as an example in this paper. DA - 2013/9// PY - 2013/9// DO - 10.1016/j.snb.2013.05.069 VL - 186 SP - 52-55 J2 - Sensors and Actuators B: Chemical LA - en OP - SN - 0925-4005 UR - http://dx.doi.org/10.1016/j.snb.2013.05.069 DB - Crossref KW - Electrospinning KW - Sensor KW - Polymer KW - Printed electrodes KW - Carbon nanotubes ER - TY - JOUR TI - Quantitative Analysis of Phosphoinositide 3-Kinase (PI3K) Signaling Using Live-Cell Total Internal Reflection Fluorescence (TIRF) Microscopy AU - Johnson, Heath E. AU - Haugh, Jason M. T2 - Current Protocols in Cell Biology AB - Abstract This unit focuses on the use of total internal reflection fluorescence (TIRF) microscopy and image analysis methods to study the dynamics of signal transduction mediated by class I phosphoinositide 3‐kinases (PI3Ks) in mammalian cells. The first four protocols cover live‐cell imaging experiments, image acquisition parameters, and basic image processing and segmentation. These methods are generally applicable to live‐cell TIRF experiments. The remaining protocols outline more advanced image analysis methods, which were developed in our laboratory for the purpose of characterizing the spatiotemporal dynamics of PI3K signaling. These methods may be extended to analyze other cellular processes monitored using fluorescent biosensors. Curr. Protoc. Cell Biol . 61:14.14.1‐14.14.24. © 2013 by John Wiley & Sons, Inc. DA - 2013/// PY - 2013/// DO - 10.1002/0471143030.cb1414s61 ER - TY - JOUR TI - Model-based design of synthetic, biological systems AU - Crook, Nathan AU - Alper, Hal S. T2 - Chemical Engineering Science AB - Synthetic biology brings engineering tools and perspectives to the design of living systems. In contrast to classical cell engineering approaches, synthetic biology enables cellular networks to be understood as a combination of modular elements in much the same way as unit operations combine to describe a chemical plant. Consequently, models for the behavior of these designed systems are inspired by frameworks developed for traditional chemical engineering design. There are direct analogies between cellular metabolism and reaction networks in a chemical process. As examples, thermodynamic and kinetic models of chemical reaction networks have been used to simulate fluxes within living systems and predict the performance of synthetic parts. Concepts from process control have been brought to bear on the design of transcriptional and translational regulatory networks. Such engineering frameworks have greatly aided the design and understanding of living systems and have enabled the design of cells exhibiting complex dynamic behavior and high productivity of desirable compounds. This review summarizes efforts to quantitatively model cellular behavior (both endogenous and synthetic), especially as related to the design of living systems. DA - 2013/11// PY - 2013/11// DO - 10.1016/j.ces.2012.12.022 VL - 103 SP - 2-11 KW - Cellular biology and engineering KW - Mathematical modeling KW - Biological and biomolecular engineering KW - Metabolism KW - Molecular biology KW - Synthetic biology ER - TY - JOUR TI - Synthesis of Mixed Ceramic MgxZn1–xO Nanofibers via Mg2+ Doping Using Sol–Gel Electrospinning AU - Aykut, Yakup AU - Parsons, Gregory N. AU - Pourdeyhimi, Behnam AU - Khan, Saad A. T2 - Langmuir AB - We report on the synthesis of tuned energy band gap MgxZn1–xO nanofibers (NFs) with different Mg2+ content via the sol–gel electrospinning (ES) technique wherein the addition of the doping material affects not only the morphologies of as-spun ZnAc/PVA and MgAc/ZnAc/PVA nanofibers but also the crystal microstructure and optical properties of calcined ZnO and MgxZn1–xO nanofibers. Following an appropriate aqueous solution preparation of magnesium acetate (MgAc) and zinc acetate (ZnAc) with poly(vinyl alcohol) (PVA), electrospinning is performed and then as-spun nanofibers are calcined in an air atmosphere at 600 °C for 3 h. As-spun and calcined nanofiber diameters and morphologies are evaluated with scanning (SEM) and transmission (TEM) electron microscopies, whereas crystalline microstructural interpretations of ZnO and MgxZn1–xO are conducted with wide-angle X-ray diffraction spectra (XRD). Surface chemical composition and elemental evaluation of calcined nanofibers are examined with X-ray photoelectron spectroscopy (XPS), and optical properties and crystal defect analyses of the calcined nanofibers are conducted with photoluminescence spectra (PL). We observe a sharp reduction in fiber diameter upon calcination as a result of the removal of organic species from the fibers and conversion of ceramic precursors into ceramic nanofibers, and the appearance of a range of fiber morphologies from “bead in a string” to “sesame seed” coverage depending on fiber composition. Because Zn2+ and Mg2+ have similar ionicity and atomic radii, some Zn2+ atoms are replaced by Mg2+ atoms in the crystals, leading to a change in the properties of crystal lattices. The band gap energy of the calcined fibers increases significantly with addition of Mg2+ along with an increase in the ultraviolet (UV) photoluminescence emission of the fibers. DA - 2013/3/15/ PY - 2013/3/15/ DO - 10.1021/LA400281C VL - 29 IS - 12 SP - 4159-4166 J2 - Langmuir LA - en OP - SN - 0743-7463 1520-5827 UR - http://dx.doi.org/10.1021/LA400281C DB - Crossref ER - TY - JOUR TI - Alginate–Polyethylene Oxide Blend Nanofibers and the Role of the Carrier Polymer in Electrospinning AU - Saquing, Carl D. AU - Tang, Christina AU - Monian, Brinda AU - Bonino, Christopher A. AU - Manasco, Joshua L. AU - Alsberg, Eben AU - Khan, Saad A. T2 - Industrial & Engineering Chemistry Research AB - We present here a systematic investigation to understand why aqueous sodium alginate can only be electrospun into fibers through a blend with another polymer; specifically, polyethylene oxide (PEO). We seek to examine and understand the role of PEO as the “carrier polymer”. The addition of PEO favorably reduces electrical conductivity and surface tension of the alginate solution, aiding in fiber formation. While PEO has the ability to coordinate through its ether group (−COC−) with metal cation like the sodium cation of sodium alginate, we demonstrate in this study using PEO as well as polyvinyl alcohol (PVA) that coordination may have little effect on electrospinnability. More importantly, we show that PEO as carrier polymer provides molecular entanglement that is required for electrospinning. Since the selected carrier polymer provides the necessary entanglement, this carrier polymer must be electrospinnable, entangled and of a high molecular weight (more than 600 kDa for PEO). On the basis of these requirements, we stipulate that the PEO–PEO interaction of the high molecular-weight entangled PEO is key to “carrying” the alginate from solution to fibers during electrospinning. Further, using the resulting understanding of the role of PEO, we were able to increase the alginate concentration by employing a higher molecular-weight PEO: up to 70 wt % alginate using 2000 kDa PEO and, with, the addition of Triton X-100 surfactant, up to 85 wt % alginate, higher than previously reported. DA - 2013/3/19/ PY - 2013/3/19/ DO - 10.1021/IE302385B VL - 52 IS - 26 SP - 8692-8704 J2 - Ind. Eng. Chem. Res. LA - en OP - SN - 0888-5885 1520-5045 UR - http://dx.doi.org/10.1021/IE302385B DB - Crossref ER - TY - JOUR TI - Effects of surfactants on the microstructures of electrospun polyacrylonitrile nanofibers and their carbonized analogs AU - Aykut, Yakup AU - Pourdeyhimi, Behnam AU - Khan, Saad A. T2 - Journal of Applied Polymer Science AB - ABSTRACT In this study, the influence of surfactants on the processability of electrospun polyacrylonitrile (PAN) nanofibers and their carbonized analogs was investigated. The surfactants employed in this effort are Triton X‐100 (nonionic surfactant, SF‐N), sodium dodecyl sulfate (SDS) (anionic surfactant, SF‐A), and hexadecyltrimethylammonium bromide (HDTMAB) (cationic surfactant, SF‐C). Interactions between electrospun PAN and the surfactants, reflected in effects on as‐spun and carbonized nanofiber morphologies and microstructures, were explored. The results show that uniform nanofibers are obtained when cationic and anionic surfactants (surfactant free and nonionic surfactants) are utilized in the preparation of electrospun PAN. In contrast, a bead‐on‐a‐string morphology results when the aniconic and cationic surfactants are present, and defect structure is enhanced with cationic surfactant addition. Moreover, fiber breakage is observed when the nonionic surfactant Triton X‐100 is employed for electrospinning. After carbonizaition, the PAN polymers were observed to have less ordered structures with addition of any type of surfactant used for electrospinning and the disorder becomes more pronounced when the anionic surfactant is utilized. Owing to the fact that microstructure defects create midband gap states that enable more electrons to be emitted from the fiber, an enhancement of electron emission is observed for PAN electrospun in the presence of the anionic surfactant. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3726–3735, 2013 DA - 2013/6/29/ PY - 2013/6/29/ DO - 10.1002/APP.39637 VL - 130 IS - 5 SP - 3726-3735 J2 - J. Appl. Polym. Sci. LA - en OP - SN - 0021-8995 UR - http://dx.doi.org/10.1002/APP.39637 DB - Crossref KW - electrospinning KW - nanostructured polymers KW - morphology ER - TY - JOUR TI - ASI:Dunaliellamarine microalgae to drop-in replacement liquid transportation fuel AU - Wang, Wei-Cheng AU - Allen, Elle AU - Campos, Andrew A. AU - Cade, Rushyannah Killens AU - Dean, Lisa AU - Dvora, Mia AU - Immer, Jeremy G. AU - Mixson, Stephanie AU - Srirangan, Soundarya AU - Sauer, Marie-Laure AU - Schreck, Steven AU - Sun, Keyi AU - Thapaliya, Nirajan AU - Wilson, Cameron AU - Burkholder, JoAnn AU - Grunden, Amy M. AU - Lamb, H. Henry AU - Sederoff, Heike AU - Stikeleather, Larry F. AU - Roberts, William L. T2 - Environmental Progress & Sustainable Energy AB - Microalgae are a promising biofuels feedstock, theoretically yielding concentrations of triacylglycerides (TAGs) per unit area that are far higher than traditional feedstocks due to their rapid growth. Dunaliella is particularly advantageous as a feedstock because it is currently commercially mass cultured, thrives in salt water, and has no cell wall. Fourteen strains of Dunaliella have been investigated for growth rates and lipid production in mass culture and tested for enhanced lipid production under a range of environmental stressors including salinity, pH, nitrogen and phosphorus limitation, and light regime. The nuclear genome has been sequenced for four of these strains, with the objective of increasing carbon flux through genetic engineering. Electroflocculation followed by osmotic membrane rupturing may be a very energy and cost efficient means of harvesting the lipid bodies from Dunaliella. A technically feasible and scalable thermo-catalytic process to convert the lipids into replacements for liquid transportation fuels has been developed. The lipids were converted into long-chain alkanes through continuous thermal hydrolysis followed by fed-batch thermo-catalytic decarboxylation. These alkanes can be reformed into renewable diesel via conventional catalytic hydrocarbon isomerization reactions to improve cold flow properties, if desired. © 2013 American Institute of Chemical Engineers Environ Prog, 32: 916–925, 2013 DA - 2013/9/11/ PY - 2013/9/11/ DO - 10.1002/EP.11855 VL - 32 IS - 4 SP - 916-925 J2 - Environ. Prog. Sustainable Energy LA - en OP - SN - 1944-7442 UR - http://dx.doi.org/10.1002/EP.11855 DB - Crossref ER - TY - JOUR TI - A generalized approach for measuring microcapsule permeability with Fluorescence Recovery After Photobleaching AU - Scrimgeour, Jan AU - San-Miguel, Adriana AU - Curtis, Jennifer E. AU - Behrens, Sven H. T2 - Journal of Materials Science DA - 2013/3// PY - 2013/3// DO - 10.1007/S10853-012-6997-7 VL - 48 IS - 5 SP - 2215–2223 SN - 0022-2461 1573-4803 UR - http://dx.doi.org/10.1007/S10853-012-6997-7 ER - TY - JOUR TI - Microstructures: 3D Printing of Free Standing Liquid Metal Microstructures (Adv. Mater. 36/2013) AU - Ladd, Collin AU - So, Ju-Hee AU - Muth, John AU - Dickey, Michael D. T2 - Advanced Materials AB - A direct-write method for writing 3D freestanding, liquid-metal microcomponents from the binary eutectic alloy of gallium and indium at room temperature is described in work by Prof. Michael Dickey, Prof. John Muth, and co-workers on page 5081. The smallest components fabricated by the technique are of the order of 10 μm in size, and smaller–sized structures may be possible. The technique allows the formation of mechanically stable structures and is capable of printing wires, spheres, arches, and interconnects. DA - 2013/9// PY - 2013/9// DO - 10.1002/ADMA.201370225 VL - 25 IS - 36 SP - 4953-4953 J2 - Adv. Mater. LA - en OP - SN - 0935-9648 UR - http://dx.doi.org/10.1002/ADMA.201370225 DB - Crossref ER - TY - JOUR TI - Macromol. Theory Simul. 1/2013 AU - Bain, Erich D. AU - Turgman-Cohen, Salomon AU - Genzer, Jan T2 - Macromolecular Theory and Simulations AB - Cover: Polymerizations in confined geometries result in deviations from predicted properties, including molecular weight distribution, topology, and composition. Similar effects are encountered in surface-initiated polymerizations, where confinement arises from grafting of chain ends. Recent developments in computer simulations of bulk, confined, and surface-initiated polymerizations are reviewed, and the cover image compares systems with varying degrees of confinement and analogous surface-initiated examples. Further details can be found in the article by E. D. Bain, S. Turgman-Cohen, J. Genzer* on page 8. DA - 2013/1// PY - 2013/1// DO - 10.1002/mats.201370001 VL - 22 IS - 1 SP - 1-1 J2 - Macromol. Theory Simul. LA - en OP - SN - 1022-1344 UR - http://dx.doi.org/10.1002/mats.201370001 DB - Crossref ER - TY - JOUR TI - Pan-neuronal maturation but not neuronal subtype differentiation of adult neural stem cells is mechanosensitive AU - Keung, Albert J. AU - Dong, Meimei AU - Schaffer, David V. AU - Kumar, Sanjay T2 - Scientific Reports AB - Most past studies of the biophysical regulation of stem cell differentiation have focused on initial lineage commitment or proximal differentiation events. It would be valuable to understand whether biophysical inputs also influence distal endpoints more closely associated with physiological function, such as subtype specification in neuronal differentiation. To explore this question, we cultured adult neural stem cells (NSCs) on variable stiffness ECMs under conditions that promote neuronal fate commitment for extended time periods to allow neuronal subtype differentiation. We find that ECM stiffness does not modulate the expression of NeuroD1 and TrkA/B/C or the percentages of pan-neuronal, GABAergic, or glutamatergic neuronal subtypes. Interestingly, however, an ECM stiffness of 700 Pa maximizes expression of pan-neuronal markers. These results suggest that a wide range of stiffnesses fully permit pan-neuronal NSC differentiation, that an intermediate stiffness optimizes expression of pan-neuronal genes, and that stiffness does not impact commitment to particular neuronal subtypes. DA - 2013/5/10/ PY - 2013/5/10/ DO - 10.1038/SREP01817 VL - 3 IS - 1 J2 - Sci Rep LA - en OP - SN - 2045-2322 UR - http://dx.doi.org/10.1038/SREP01817 DB - Crossref ER - TY - JOUR TI - Producing biodiesel from cottonseed oil using Rhizopus oryzae ATCC #34612 whole cell biocatalysts: Culture media and cultivation period optimization AU - Athalye, Sneha AU - Sharma-Shivappa, Ratna AU - Peretti, Steven AU - Kolar, Praveen AU - Davis, Jack P. T2 - Energy for Sustainable Development AB - The effect of culture medium composition and cultivation time on biodiesel production by Rhizopus oryzae ATCC #34612 whole cell catalysts, immobilized on novel rigid polyethylene biomass supports, was investigated. Supplementation of the medium with carbon sources led to higher lipase activity and increased the biomass immobilized on the BSPs. Statistical analysis indicates that a cultivation period of 72 h in a basal medium supplemented with both cottonseed oil and glucose is optimal for biodiesel production by R. oryzae, resulting in a fatty acid methyl ester (FAME) yield of 27.9 wt.% (228.2 g/L). DA - 2013/8// PY - 2013/8// DO - 10.1016/J.ESD.2013.03.009 VL - 17 IS - 4 SP - 331-336 J2 - Energy for Sustainable Development LA - en OP - SN - 0973-0826 UR - http://dx.doi.org/10.1016/J.ESD.2013.03.009 DB - Crossref KW - Rhizopus oryzae KW - Biodiesel KW - Cottonseed oil KW - Whole cell biocatalysts KW - Fungal catalysis ER - TY - JOUR TI - Carbohydrate and lignin are simultaneously solubilized from unpretreated switchgrass by microbial action at high temperature AU - Kataeva, Irina AU - Foston, Marcus B. AU - Yang, Sung-Jae AU - Pattathil, Sivakumar AU - Biswal, Ajaya K. AU - Poole II, Farris L. AU - Basen, Mirko AU - Rhaesa, Amanda M. AU - Thomas, Tina P. AU - Azadi, Parastoo AU - Olman, Victor AU - Saffold, Trina D. AU - Mohler, Kyle E. AU - Lewis, Derrick L. AU - Doeppke, Crissa AU - Zeng, Yining AU - Tschaplinski, Timothy J. AU - York, William S. AU - Davis, Mark AU - Mohnen, Debra AU - Xu, Ying AU - Ragauskas, Art J. AU - Ding, Shi-You AU - Kelly, Robert M. AU - Hahn, Michael G. AU - Adams, Michael W. W. T2 - Energy & Environmental Science AB - The three major components of plant biomass, cellulose, hemicellulose and lignin, are highly recalcitrant and deconstruction involves thermal and chemical pretreatment. Microbial conversion is a possible solution, but few anaerobic microbes utilize both cellulose and hemicellulose and none are known to solubilize lignin. Herein, we show that the majority (85%) of insoluble switchgrass biomass that had not been previously chemically treated was degraded at 78 °C by the anaerobic bacterium Caldicellulosiruptor bescii. Remarkably, the glucose/xylose/lignin ratio and physical and spectroscopic properties of the remaining insoluble switchgrass were not significantly different than those of the untreated plant material. C. bescii is therefore able to solubilize lignin as well as the carbohydrates and, accordingly, lignin-derived aromatics were detected in the culture supernatants. From mass balance analyses, the carbohydrate in the solubilized switchgrass quantitatively accounted for the growth of C. bescii and its fermentation products, indicating that the lignin was not assimilated by the microorganism. Immunoanalyses of biomass and transcriptional analyses of C. bescii showed that the microorganism when grown on switchgrass produces enzymes directed at key plant cell wall moieties such as pectin, xyloglucans and rhamnogalacturonans, and that these and as yet uncharacterized enzymes enable the degradation of cellulose, hemicellulose and lignin at comparable rates. This unexpected finding of simultaneous lignin and carbohydrate solubilization bodes well for industrial conversion by extremely thermophilic microbes of biomass that requires limited or, more importantly, no chemical pretreatment. DA - 2013/// PY - 2013/// DO - 10.1039/C3EE40932E VL - 6 IS - 7 SP - 2186 J2 - Energy Environ. Sci. LA - en OP - SN - 1754-5692 1754-5706 UR - http://dx.doi.org/10.1039/C3EE40932E DB - Crossref ER - TY - JOUR TI - simple method to encapsulate SnSb nanoparticles into hollow carbon nanofibers with superior lithium-ion storage capability AU - Xue, L. G. AU - Xia, X. AU - Tucker, T. AU - Fu, K. AU - Zhang, S. AU - Li, S. L. AU - Zhang, X. W. T2 - Journal of Materials Chemistry A DA - 2013/// PY - 2013/// VL - 1 ER - TY - JOUR TI - Synthesis and characterization of xLi(2)MnO(3) center dot (1-x)LiMn1/3Ni1/3Co1/3O2 composite cathode materials for rechargeable lithium-ion batteries AU - Toprakci, O. AU - Toprakci, H. A. K. AU - Li, Y. AU - Ji, L. W. AU - Xue, L. G. AU - Lee, H. AU - Zhang, S. AU - Zhang, X. W. T2 - Journal of Power Sources DA - 2013/// PY - 2013/// VL - 241 ER - TY - JOUR TI - Si/C composite nanofibers with stable electric conductive network for use as durable lithium-ion battery anode AU - Xue, L. G. AU - Fu, K. AU - Li, Y. AU - Xu, G. J. AU - Lu, Y. AU - Zhang, S. AU - Toprakci, O. AU - Zhang, X. W. T2 - Nano Energy DA - 2013/// PY - 2013/// VL - 2 ER - TY - CHAP TI - PRINT Technology: A Versatile Platform for Novel Applications in Nanomedicine AU - Byrne, J.D. AU - Hasan, W. AU - Blake, S. AU - Farrell, C. AU - DeSimone, J. T2 - Nanomaterials for Pharmaceutical Scientists A2 - Yin, S. A2 - Wei, A. PY - 2013/// PB - Wiley ER - TY - JOUR TI - Nanotechnology: An Enduring Bridge Between Engineering and Medicine AU - Petrosko, S.H. AU - Fromen, C.A. AU - Auyeung, E. AU - DeSimone, J.M. AU - Mirkin, C.A. T2 - The Bridge: Linking Engineering and Society DA - 2013/// PY - 2013/// SP - 7–15 ER - TY - JOUR TI - Development of a nanoparticle-based influenza vaccine using the PRINT® technology AU - Galloway, Ashley L. AU - Murphy, Andrew AU - DeSimone, Joseph M. AU - Di, Jie AU - Herrmann, Jennifer P. AU - Hunter, Michael E. AU - Kindig, Jeffrey P. AU - Malinoski, Frank J. AU - Rumley, Megan A. AU - Stoltz, Daria M. AU - Templeman, Thomas S. AU - Hubby, Bolyn T2 - Nanomedicine: Nanotechnology, Biology and Medicine AB - Historically it is known that presentation of vaccine antigens in particulate form, for a wide range of pathogens, has clear advantages over the presentation of soluble antigen alone [J.C. Aguilar, E.G. Rodriguez, Vaccine adjuvants revisited. Vaccine 25 (2007) 3752–3762, M. Singh, D. O'Hagan, Advances in vaccine adjuvants. Nature Biotechnology 17 (1999) 1075–1081]. Herein we describe a novel particle-based approach, which independently controls size, shape, and composition to control the delivery and presentation of vaccine antigen to the immune system. Highly uniform particles were produced using a particle molding technology called PRINT® (Particle Replication in Non-wetting Templates) which is an off-shoot of imprint lithography [J Am Chem Soc 127 (2005) 10096–10100, J Am Chem Soc 126 (2004) 2322–2323, Chem Soc Rev 35 (2006) 1095–1104, J Am Chem Soc 130 (2008) 5008–5009, J Am Chem Soc 130 (2008) 5438–5439, Polymer Reviews 47 (2007) 321–327, Acc Chem Res 41 (2008) 1685–1695, Acc Chem Res 44 (10) (2011) 990–998]. Cylindrical (diameter [d] = 80 nm, height [h] = 320 nm) poly (lactide-co-glycolide) (PLGA) based PRINT particles were designed to electrostatically bind commercial trivalent injectable influenza vaccine. In a variety of blended PLGA formulations, these particles were safe and showed enhanced responses to influenza hemagglutinin in murine models. Shape is one of the determining factors in interactions of nanoparticles with their biologic environment. PRINT technology is able to fabricate nearly uniform nanoparticles and this technology is tested here in murine models to effectively deliver influenza vaccine. DA - 2013/5// PY - 2013/5// DO - 10.1016/j.nano.2012.11.001 VL - 9 IS - 4 SP - 523-531 J2 - Nanomedicine: Nanotechnology, Biology and Medicine LA - en OP - SN - 1549-9634 UR - http://dx.doi.org/10.1016/j.nano.2012.11.001 DB - Crossref KW - Nanotechnology KW - Influenza vaccine KW - PRINT KW - Soft lithography KW - Hemagglutinin ER - TY - BLOG TI - Second Phase of Education: Lane Daley at Eastman Chemical in Kingsport AU - Westmoreland, P.R. T2 - ChEnected DA - 2013/12/4/ PY - 2013/12/4/ UR - https://www.aiche.org/chenected/2013/12/second-phase-education-lane-daley-eastman-chemical-kingsport ER - TY - BLOG TI - Second Phase of Education: Mariam Al-Meer at Shell in Qatar AU - Westmoreland, P.R. T2 - ChEnected DA - 2013/11/21/ PY - 2013/11/21/ PB - American Institute of Chemical Engineers UR - https://www.aiche.org/chenected/2013/11/second-phase-education-mariam-al-meer-shell-qatar ER - TY - BLOG TI - The Second Phase of ChE Education AU - Westmoreland, P.R. T2 - ChEnected DA - 2013/10/23/ PY - 2013/10/23/ PB - American Institute of Chemical Engineers UR - https://www.aiche.org/chenected/2013/10/second-phase-che-education ER - TY - JOUR TI - Electrospun nanofiber-coated separator membranes for lithium-ion rechargeable batteries AU - Lee, Hun AU - Alcoutlabi, Mataz AU - Watson, Jill V. AU - Zhang, Xiangwu T2 - Journal of Applied Polymer Science AB - Abstract Nanofiber‐coated composite membranes were prepared by electrospinning polyvinylidene fluoride‐ co ‐chlorotrifluoroethylene (PVDF‐ co ‐CTFE) and PVDF‐ co ‐CTFE/polyvinylidene fluoride‐ co ‐hexafluoropropylene (PVDF‐ co ‐HFP) onto six different Celgard® microporous battery separator membranes. Application of a PVDF‐based copolymer nanofiber coating onto the surface of the battery separator membrane provides a method for improving the electrolyte absorption of the separator and the separator‐electrode adhesion. Peel tests showed that both PVDF‐ co ‐CTFE and PVDF‐ co ‐CTFE/PVDF‐ co ‐HFP nanofiber coatings have comparable adhesion to the membrane substrates. Electrolyte uptake capacity was investigated by soaking the nanofiber‐coated membranes in a liquid electrolyte solution. PVDF‐ co ‐CTFE and PVDF‐ co ‐CTFE/PVDF‐ co ‐HFP nanofiber‐coated membranes exhibited higher electrolyte uptake capacities than uncoated membranes. It was also found that PVDF‐ co ‐CTFE nanofiber‐coated membranes have higher electrolyte uptakes than PVDF‐ co ‐CTFE/PVDF‐ co ‐HFP nanofiber‐coated membranes due to the smaller diameters of PVDF‐ co ‐CTFE nanofibers and higher polarity of PVDF‐ co ‐CTFE. The separator–electrode adhesion properties were also investigated. Results showed PVDF‐ co ‐CTFE and PVDF‐ co ‐CTFE/PVDF‐ co ‐HFP nanofiber coatings improved the adhesion of all six membrane substrates to the electrode. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 DA - 2013/// PY - 2013/// DO - 10.1002/app.38894 VL - 129 IS - 4 SP - 1939-1951 UR - https://publons.com/publon/7178362/ KW - batteries and fuel cells KW - blends KW - coatings ER - TY - CONF TI - Loose Change and Dishwasher Optimization: Creative Applications of Engineering Statistics AU - Cooper, M. C2 - 2013/// C3 - Proceedings of the ASEE National Meeting CY - Atlanta, GA DA - 2013/// ER - TY - JOUR TI - The Case Against the Use of Solution Manuals AU - Bullard, L.G. T2 - Chemical Engineering Education DA - 2013/// PY - 2013/// VL - 47 IS - 1 ER - TY - JOUR TI - Navigating the Grad School Application Process: A Training Schedule AU - Swindlehurst, G.R. AU - Bullard, L.G. T2 - Chemical Engineering Education DA - 2013/// PY - 2013/// VL - 47 IS - 4 ER - TY - JOUR TI - Design of Linear Ligands for Selective Separation Using a Genetic Algorithm Applied to Molecular Architecture AU - Santiso, Erik E. AU - Musolino, Nicholas AU - Trout, Bernhardt L. T2 - Journal of Chemical Information and Modeling AB - Continuous purification of chemical reaction products through adsorption-based operations during workup may present advantages over batch chromatography or crystallization. In pharmaceutical syntheses, however, the desired product is often structurally similar to byproducts or unconverted reactant, so that identifying a suitable adsorption medium is challenging. We developed an in silico screening process to design organic ligands which, when chemically bound to a solid surface, would constitute an effective adsorption for a pharmaceutically relevant mixture of reaction products. This procedure employs automated molecular dynamics simulations to evaluate potential ligands, by measuring the difference in adsorption energy of two solutes which differed by one functional group. Then, a genetic algorithm was used to iteratively improve a population of such ligands through selection and reproduction steps. This procedure identified chemical designs of the surface-bound ligands that were outside the set we considered using chemical intuition. The ligand designs achieved selectivity by exploiting phenyl-phenyl stacking which was sterically hindered in the case of one solution component. The ligand designs had selectivity energies of 0.8-1.6 kcal/mol in single-ligand, solvent-free simulations, if entropic contributions to the relative selectivity are neglected. We believe this molecular evolution technique presents a useful method for the directed exploration of chemical space or for molecular design, when the chemical properties of interest can be efficiently evaluated through simulations. DA - 2013/7/11/ PY - 2013/7/11/ DO - 10.1021/ci400043q VL - 53 IS - 7 SP - 1638-1660 J2 - J. Chem. Inf. Model. LA - en OP - SN - 1549-9596 1549-960X UR - http://dx.doi.org/10.1021/ci400043q DB - Crossref ER - TY - CONF TI - XanoShear™ Large-scale fabrication of functional Nanofibers AU - Vitchuli, N. AU - Tian, T. AU - Smoukov, S. AU - Gangwal, S. AU - Geisen, P. AU - Wright, M. AU - Velev, O. C2 - 2013/// C3 - International Symposium on Fibers Interfacing the World DA - 2013/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84969813025&partnerID=MN8TOARS ER - TY - BOOK TI - Transport control of fluid and solutes in microchannels using ac field and semiconductor diodes AU - Petsev, D.N. AU - Velev, O.D. DA - 2013/// PY - 2013/// SE - 241-258 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84892285213&partnerID=MN8TOARS ER - TY - JOUR TI - Stability and Viscoelasticity of Magneto-Pickering Foams AU - Blanco, Elena AU - Lam, Stephanie AU - Smoukov, Stoyan K. AU - Velikov, Krassimir P. AU - Khan, Saad A. AU - Velev, Orlin D. T2 - Langmuir AB - We have developed a new class of bistable Pickering foams, which can remain intact for weeks at room temperature but can be destroyed rapidly and on-demand with the use of a magnetic field. Such responsive foam systems can find application in various industrial and environmental processes that require controlled defoaming. These foams are stabilized by particles of hypromellose phthalate (HP-55) and contain oleic acid-coated carbonyl iron particles embedded in the HP-55 matrix. The complex behavior of these foams arises from several factors: a robust anisotropic particle matrix, the capacity to retain a high amount of water, as well as an age-dependent response to an external field. We report how the structure and viscoelastic properties of the foams change with time and affect their collapse characteristics. The evolution of foam properties is quantified by measuring the rate of liquid drainage from the foam as well as the rate of bubble growth in the foam with respect to time elapsed (in the absence of a magnetic field). We also evaluate the time necessary for foam collapse in magnetic fields as a function of magnetic particle content. A decreasing liquid volume fraction in the foam during aging leads to an increase in the elasticity and rigidity of the foam structure. These data allow us to identify a transition time separating two distinct stages of foam development in the absence of field. We propose different mechanisms which control foam collapse for each stage in a magnetic field. The stiffening of foam films between air bubbles with age plays a key role in distinguishing between the two destabilization regimes. DA - 2013/8/2/ PY - 2013/8/2/ DO - 10.1021/LA4014224 VL - 29 IS - 32 SP - 10019-10027 J2 - Langmuir LA - en OP - SN - 0743-7463 1520-5827 UR - http://dx.doi.org/10.1021/LA4014224 DB - Crossref ER - TY - CONF TI - External field directed co-assembly of rigid and ultra-flexible permanent chains AU - Bharti, B. AU - Fameau, A.L. AU - Findenegg, G.H. AU - Velev, O.D. C2 - 2013/// C3 - Engineering Sciences and Fundamentals 2013 - Core Programming Area at the 2013 AIChE Annual Meeting: Global Challenges for Engineering a Sustainable Future DA - 2013/// VL - 2 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84911871745&partnerID=MN8TOARS ER - TY - JOUR TI - Exploring a direct injection method for microfluidic generation of polymer microgels AU - Wang, Yihe AU - Tumarkin, Ethan AU - Velasco, Diego AU - Abolhasani, Milad AU - Lau, Willie AU - Kumacheva, Eugenia T2 - Lab on a Chip AB - Microfluidics (MFs) offers a promising method for the preparation of polymer microgels with exquisite control over their dimensions, shapes and morphologies. A challenging task in this process is the generation of droplets (precursors for microgels) from highly viscous polymer solutions. Spatial separation of MF emulsification and gelation of the precursor droplets on chip can address this challenge. In the present work, we explored the application of the “direct injection” method for the preparation of microgels by adding a highly concentrated polymer solution or a gelling agent directly into the precursor droplets. In the first system, primary droplets were generated from a dilute aqueous solution of agarose, followed by the injection of the concentrated agarose solution directly in the primary droplets. The secondary droplets served as precursors for microgels. In the second system, primary droplets were generated from the low-viscous solution of methyl-β-cyclodextrin and poly(ethylene glycol) end-terminated with octadecyl hydrophobic groups. Addition of surfactant directly into the primary droplets led to the binding of methyl-β-cyclodextrin to the surfactant, thereby releasing hydrophobized poly(ethylene glycol) to form polymer microgels. Our results show that, when optimized, the direct injection method can be used for microgel preparation from highly viscous liquids and thus this method expands the range of polymers used for MF generation of microgels. DA - 2013/// PY - 2013/// DO - 10.1039/c3lc41385c VL - 13 IS - 13 SP - 2547 ER - TY - JOUR TI - Bubble gate for in-plane flow control AU - Oskooei, Ali AU - Abolhasani, Milad AU - Günther, Axel T2 - Lab on a Chip AB - We introduce a miniature gate valve as a readily implementable strategy for actively controlling the flow of liquids on-chip, within a footprint of less than one square millimetre. Bubble gates provide for simple, consistent and scalable control of liquid flow in microchannel networks, are compatible with different bulk microfabrication processes and substrate materials, and require neither electrodes nor moving parts. A bubble gate consists of two microchannel sections: a liquid-filled channel and a gas channel that intercepts the liquid channel to form a T-junction. The open or closed state of a bubble gate is determined by selecting between two distinct gas pressure levels: the lower level corresponds to the “open” state while the higher level corresponds to the “closed” state. During closure, a gas bubble penetrates from the gas channel into the liquid, flanked by a column of equidistantly spaced micropillars on each side, until the flow of liquid is completely obstructed. We fabricated bubble gates using single-layer soft lithographic and bulk silicon micromachining procedures and evaluated their performance with a combination of theory and experimentation. We assessed the dynamic behaviour during more than 300 open-and-close cycles and report the operating pressure envelope for different bubble gate configurations and for the working fluids: de-ionized water, ethanol and a biological buffer. We obtained excellent agreement between the experimentally determined bubble gate operational envelope and a theoretical prediction based on static wetting behaviour. We report case studies that serve to illustrate the utility of bubble gates for liquid sampling in single and multi-layer microfluidic devices. Scalability of our strategy was demonstrated by simultaneously addressing 128 bubble gates. DA - 2013/// PY - 2013/// DO - 10.1039/c3lc50075f VL - 13 IS - 13 SP - 2519 ER - TY - JOUR TI - On-Chip Cytometry using Plasmonic Nanoparticle Enhanced Lensfree Holography AU - Wei, Q. S. AU - McLeod, E. AU - Qi, H. F. AU - Wan, Z. AU - Sun, R. AU - Ozcan, A. T2 - Scientific Reports AB - Computational microscopy tools, in particular lensfree on-chip imaging, provide a large field-of-view along with a long depth-of-field, which makes it feasible to rapidly analyze large volumes of specimen using a compact and light-weight on-chip imaging architecture. To bring molecular specificity to this high-throughput platform, here we demonstrate the use of plasmon-resonant metallic nanoparticles to automatically recognize different cell types based on their plasmon-enhanced lensfree holograms, detected and reconstructed over a large field-of-view of e.g., ~24 mm². DA - 2013/// PY - 2013/// DO - 10.1038/srep01699 VL - 3 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000317892500002&KeyUID=WOS:000317892500002 ER - TY - CONF TI - Lensfree holographic cytometry using plasmonic nanoparticles AU - Wei, Q. AU - McLeod, E. AU - Qi, H. AU - Wan, Z. AU - Sun, R. AU - Ozcan, A. AB - Cellular contrast was demonstrated for the first time in lensfree on-chip holography by employing antibody-conjugated gold and silver nanoparticles (NPs) as contrast agents. Cytometric differentiation of CD4+ and CD8+ lymphocytes was achieved, after NP labeling, using machine learning algorithms. C2 - 2013/// C3 - 2013 IEEE Photonics Conference, IPC 2013 DA - 2013/// DO - 10.1109/IPCon.2013.6656337 SP - 3-4 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84892689806&partnerID=MN8TOARS ER - TY - JOUR TI - Giga-pixel fluorescent imaging over an ultra-large field-of-view using a flatbed scanner AU - Gorocs, Z. AU - Ling, Y. Y. AU - Yu, M. D. AU - Karahalios, D. AU - Mogharabi, K. AU - Lu, K. AU - Wei, Q. S. AU - Ozcan, A. T2 - Lab on a Chip AB - We demonstrate a new fluorescent imaging technique that can screen for fluorescent micro-objects over an ultra-wide field-of-view (FOV) of ∼532 cm2, i.e., 19 cm × 28 cm, reaching a space-bandwidth product of more than 2 billion. For achieving such a large FOV, we modified the hardware and software of a commercially available flatbed scanner, and added a custom-designed absorbing fluorescent filter, a two-dimensional array of external light sources for computer-controlled and high-angle fluorescent excitation. We also re-programmed the driver of the scanner to take full control of the scanner hardware and achieve the highest possible exposure time, gain and sensitivity for detection of fluorescent micro-objects through the gradient index self-focusing lens array that is positioned in front of the scanner sensor chip. For example, this large FOV of our imaging platform allows us to screen more than 2.2 mL of undiluted whole blood for detection of fluorescent micro-objects within <5 minutes. This high-throughput fluorescent imaging platform could be useful for rare cell research and cytometry applications by enabling rapid screening of large volumes of optically dense media. Our results constitute the first time that a flatbed scanner has been converted to a fluorescent imaging system, achieving a record large FOV. DA - 2013/// PY - 2013/// DO - 10.1039/c3lc51005k VL - 13 IS - 22 SP - 4460-4466 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000325946800024&KeyUID=WOS:000325946800024 ER - TY - JOUR TI - Fluorescent Imaging of Single Nanoparticles and Viruses on a Smart Phone AU - Wei, Q. S. AU - Qi, H. F. AU - Luo, W. AU - Tseng, D. AU - Ki, S. J. AU - Wan, Z. AU - Gorocs, Z. AU - Bentolila, L. A. AU - Wu, T. T. AU - Sun, R. AU - Ozcan, A. T2 - Acs Nano AB - Optical imaging of nanoscale objects, whether it is based on scattering or fluorescence, is a challenging task due to reduced detection signal-to-noise ratio and contrast at subwavelength dimensions. Here, we report a field-portable fluorescence microscopy platform installed on a smart phone for imaging of individual nanoparticles as well as viruses using a lightweight and compact opto-mechanical attachment to the existing camera module of the cell phone. This hand-held fluorescent imaging device utilizes (i) a compact 450 nm laser diode that creates oblique excitation on the sample plane with an incidence angle of ∼75°, (ii) a long-pass thin-film interference filter to reject the scattered excitation light, (iii) an external lens creating 2× optical magnification, and (iv) a translation stage for focus adjustment. We tested the imaging performance of this smart-phone-enabled microscopy platform by detecting isolated 100 nm fluorescent particles as well as individual human cytomegaloviruses that are fluorescently labeled. The size of each detected nano-object on the cell phone platform was validated using scanning electron microscopy images of the same samples. This field-portable fluorescence microscopy attachment to the cell phone, weighing only ∼186 g, could be used for specific and sensitive imaging of subwavelength objects including various bacteria and viruses and, therefore, could provide a valuable platform for the practice of nanotechnology in field settings and for conducting viral load measurements and other biomedical tests even in remote and resource-limited environments. DA - 2013/// PY - 2013/// DO - 10.1021/nn4037706 VL - 7 IS - 10 SP - 9147-9155 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000326209100088&KeyUID=WOS:000326209100088 ER - TY - JOUR TI - Surface wrinkling by chemical modification of poly(dimethylsiloxane)-based networks during sputtering AU - Casper, Michelle D. AU - Gözen, Arif Ö. AU - Dickey, Michael D. AU - Genzer, Jan AU - Maria, Jon-Paul T2 - Soft Matter AB - Wrinkling is an important mechanical phenomenon that generates periodic topographical patterns across a surface. This paper presents experimental evidence that surface wrinkles, which form consequent to thin film magnetron sputtering of either indium tin oxide (ITO) or aluminum on poly(dimethylsiloxane) networks (PDMS-N) made from a commercial Sylgard-184 kit, result from chemical modification of the PDMS-N surface as opposed to extrinsic thermomechanical stresses originating from differential thermal expansion. X-ray photoelectron spectroscopy results reveal that the PDMS-N surface becomes depleted in carbon and concurrently enriched in oxygen relative to silicon due to sputtering. This silica-like surface layer possesses intrinsic compressive stress that leads to wrinkle formation during the first ≈5 seconds of sputtering. The wrinkles maintain their periodicity irrespective of the thickness of the ITO film formed during subsequent deposition. Furthermore, upon removal of the ITO layer, the wrinkles persist with their periodicity unchanged. A narrow sputtering pressure window between 2 and 12 mTorr generates wrinkles. Pressures below this range cannot sustain a radio frequency plasma, while pressures above this range provide sufficient thermalization of kinetic energy as to eliminate the energetic bombardment that modifies the PDMS-N. This study provides a new understanding of the origins of wrinkling in sputtered films on polymeric substrates and creates opportunities to manipulate the topography produced by spontaneous surface wrinkling. DA - 2013/// PY - 2013/// DO - 10.1039/C3SM50966D VL - 9 IS - 32 SP - 7797 J2 - Soft Matter LA - en OP - SN - 1744-683X 1744-6848 UR - http://dx.doi.org/10.1039/C3SM50966D DB - Crossref ER - TY - JOUR TI - Integration of pre-aligned liquid metal electrodes for neural stimulation within a user-friendly microfluidic platform AU - Hallfors, Nicholas AU - Khan, Asif AU - Dickey, Michael D. AU - Taylor, Anne Marion T2 - Lab Chip AB - Electrical stimulation of nervous tissue is used clinically for the treatment of multiple neurological disorders and experimentally for basic research. With the increase of optical probes to record neuronal activity, simple and user-friendly methods are desired to stimulate neurons and their subcellular compartments for biological experimentation. Here we describe the novel integration of liquid metal electrodes with microfluidic culture platforms to accomplish this goal. We integrated electrode and cell channels into a single poly(dimethylsiloxane) (PDMS) chip, eliminating entirely the need to align electrodes with microchannels. We designed the electrode channels such that the metal can be injected by hand and when the device is non-covalently bound to glass. We demonstrated the biocompatibility of the electrodes for long-term cultures (12 days) using hippocampal neurons. We demonstrated the use of these electrodes to depolarize neurons and recorded neuronal activity using the calcium indicator dye, Fluo-4. We established optimal stimulation parameters that induce neuronal spiking without inducing damage. We showed that the liquid metal electrode evoked larger calcium responses in somata than bath electrodes using the same stimulus parameters. Lastly we demonstrated the use of these liquid metal electrodes to target and depolarize axons. In summary, the integration of liquid metal electrodes with neuronal culture platforms provides a user-friendly and targeted method to stimulate neurons and their subcellular compartments, thus providing a novel tool for future biological investigations. DA - 2013/// PY - 2013/// DO - 10.1039/c2lc40954b VL - 13 IS - 4 SP - 522-526 ER - TY - JOUR TI - 3D Printing of Liquid Metals AU - Ladd, C. AU - Dickey, M.D. T2 - Circuit Cellar DA - 2013/// PY - 2013/// N1 - Invited RN - Invited ER - TY - JOUR TI - Novel atmospheric plasma enhanced chitosan nanofiber/gauze composite wound dressings AU - Nawalakhe, R. AU - Shi, Q. AU - Vitchuli, N. AU - Noar, J. AU - Caldwell, J. M. AU - Breidt, F. AU - Bourham, M. A. AU - Zhang, X. AU - McCord, M. G. T2 - Journal of Applied Polymer Science AB - Abstract Electrospun chitosan nanofibers were deposited onto atmospheric plasma treated cotton gauze to create a novel composite bandage with higher adhesion, better handling properties, enhanced bioactivity, and moisture management. Plasma treatment of the gauze substrate was performed to improve the durability of the nanofiber/gauze interface. The chitosan nanofibers were electrospun at 3–7% concentration in trifluoroacetic acid. The composite bandages were analyzed using peel, gelbo flex, antimicrobial assay, moisture vapor transmission rate, X‐ray photoelectron spectroscopy (XPS), absorbency, and air permeability tests. The peel test showed that plasma treatment of the substrate increased the adhesion between nanofiber layers and gauze substrate by up to four times. Atmospheric plasma pretreatment of the gauze fabric prior to electrospinning significantly reduced degradation of the nanofiber layer due to repetitive flexing. The chitosan nanofiber layer contributes significantly to the antimicrobial properties of the bandage. Air permeability and moisture vapor transport were reduced due to the presence of a nanofiber layer upon the substrate. XPS of the plasma treated cotton substrate showed formation of active sites on the surface, decrease in carbon content, and increase in oxygen content as compared to the untreated gauze. Deposition of chitosan nanofibers also increased the absorbency of gauze substrate. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 DA - 2013/// PY - 2013/// DO - https://doi.org/10.1002/app.38804 VL - 129 ER - TY - JOUR TI - Multifunctional and durable nanofiber-fabric-layered composite for protective application AU - Shi, Q. AU - Vitchuli, N. AU - Nowak, J. AU - Jiang, S. AU - Caldwell, J. M. AU - Breidt, F. AU - Bourham, M. AU - Zhang, X. W. AU - McCord, M. T2 - Journal of Applied Polymer Science AB - A multifunctional and durable nanofiber-fabric-layered composite (NFLC) material was prepared by depositing electrospun Ag/PAN hybrid nanofibers onto a Nylon/cotton 50: 50 fabric substrate. The NFLCs showed excellent aerosol barrier efficiency and good air/moisture permeability. In addition, they showed excellent antibacterial efficiency by completely inhibiting the growth of both Gram-negative E. coli and Gram-positive S. aureus. The interfacial adhesion between the nanofiber layer and fabric substrate was significantly improved by atmospheric plasma pretreatment of the substrate. The resultant NFLCs showed excellent resistance to peeling, twisting, and flexing forces. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 DA - 2013/// PY - 2013/// DO - https://doi.org/10.1002/app.38465 VL - 128 ER - TY - JOUR TI - Co3O4/Carbon Composite Nanofibers for Use as Anode Material in Advanced Lithium-Ion Batteries AU - Li, Shuli AU - Fu, Kun AU - Xue, Leigang AU - Toprakci, Ozan AU - Li, Ying AU - Zhang, Shu AU - Xu, Guanjie AU - Lu, Yao AU - Zhang, Xiangwu AU - Hu, YH AU - Burghaus, U AU - Qiao, S T2 - Nanotechnology For Sustainable Energy DA - 2013/// PY - 2013/// VL - 1140 SP - 55-66 ER - TY - CONF TI - Novel Nanofibers for Biomedical Textiles C2 - 2013/3// C3 - Joint US EPA-NCSU Interactive Collaboration Forum and Poster Session DA - 2013/3// ER - TY - CONF TI - Hybrid PEMs Incorporated with Solid Superacidic Nanofibers C2 - 2013/4// C3 - 2013 MRS Spring Meeting & Exhibit DA - 2013/4// ER - TY - CONF TI - Flexible and Binder-Free Design: Nonwoven Structure Based Si Materials as Anodes for Lithium-Ion Batteries C2 - 2013/3// C3 - The 8th Annual NC State University Graduate Student Research Symposium DA - 2013/3// ER - TY - CONF TI - Nano in Lithium-Ion Battery C2 - 2013/6// C3 - FREEDM Systems Center Student Research Workshop DA - 2013/6// ER - TY - CONF TI - High-Power and High-Energy Electrochemical Electrodes and Supercapacitors C2 - 2013/11// C3 - Center for Dielectric Studies 2013 Fall Meeting DA - 2013/11// ER - TY - JOUR TI - Heat treatment of electrospun Polyvinylidene fluoride fibrous membrane separators for rechargeable lithium-ion batteries AU - Liang, Yinzheng AU - Cheng, Sichen AU - Zhao, Jianmeng AU - Zhang, Changhuan AU - Sun, Shiyuan AU - Zhou, Nanting AU - Qiu, Yiping AU - Zhang, Xiangwu T2 - Journal of Power Sources AB - Li2MnSiO4 has been considered as a promising cathode material with an extremely high theoretically capacity of 332 mAh g−1. However, due to its low intrinsic conductivity and poor structural stability, only about half of the theoretical capacity has been realized in practice and the capacity decays rapidly during cycling. To realize the high capacity and improve the cycling performance, Li2Mn0.8Fe0.2SiO4/carbon composite nanofibers were prepared by the combination of iron doping and electrospinning. X-ray diffraction, scanning electron microscope, and transmission electronic microscope were applied to characterize the Li2Mn0.8Fe0.2SiO4/carbon nanofibers. It was found that Li2Mn0.8Fe0.2SiO4 nanoparticles were embedded into continuous carbon nanofiber matrices, which formed free-standing porous mats that could be used as binder-free cathodes. The iron doping improved the conductivity and purity of the active material, and the carbon nanofiber matrix facilitated ion transfer and charge diffusion. As a result, Li2Mn0.8Fe0.2SiO4/carbon nanofiber cathodes showed promising improvement on reversible capacity and cycling performance. DA - 2013/10// PY - 2013/10// DO - 10.1016/j.jpowsour.2012.04.011 VL - 240 SP - 204-211 UR - https://doi.org/10.1016%2Fj.jpowsour.2013.04.019 KW - Li2MnSiO4 KW - Iron doping KW - Cathode KW - Electrospinning KW - Carbon nanofibers ER - TY - CONF TI - Fast and Low-Cost Production of Nanofibers by Centrifugal Spinning C2 - 2013/8// C3 - College of Textiles’ Composites Symposium DA - 2013/8// ER - TY - CONF TI - Aligned Carbon Nanotube-Silicon f Sheets: A Novel Nano-Architecture for Flexible Lithium-ion Battery Electrodes C2 - 2013/11// C3 - North Carolina American Chemical Society’s 127th Sectional Conference DA - 2013/11// ER - TY - CONF TI - Aligned Carbon Nanotube-Silicon Sheets: A Novel Nano-Architecture for Flexible Lithium-ion Battery Electrodes C2 - 2013/11// C3 - MRS/ASM/AVS/AReMS Meeting DA - 2013/11// ER - TY - CONF TI - Aligned Carbon Nanotube-Silicon Sheets: A Novel Nano-Architecture for Flexible Lithium-ion Battery Electrodes C2 - 2013/12// C3 - 2013 MRS Fall Meeting & Exhibit DA - 2013/12// ER - TY - BOOK TI - Upstream industrial biotechnology DA - 2013/// PY - 2013/// PB - Hoboken, New Jersey: John Wiley & Sons Inc. ER - TY - BOOK TI - Encyclopedia of industrial biotechnology. Selections DA - 2013/// PY - 2013/// PB - Hoboken, New Jersey: Wiley ER - TY - JOUR TI - Implications: Societal Collective Outcomes, Including Manufacturing AU - Cao, J. AU - Meador, M. A. AU - Baba, M. L. AU - Ferreira, P. M. AU - Madou, M. AU - Scacchi, W. AU - Spohrer, J. C. AU - Teague, C. AU - Westmoreland, Phillip AU - Zhang, X. AU - al. T2 - CONVERGENCE OF KNOWLEDGE, TECHNOLOGY AND SOCIETY: BEYOND CONVERGENCE OF NANO-BIO-INFO-COGNITIVE TECHNOLOGIES AB - The convergences in advanced science and engineering interconnect with a number of core social issues that include the arrangement of means and modes of production and the associated labor skill requirements, training, costs of investments, and other matters. This chapter suggests that a highly customized, modularized, and broadly distributed manufacturing model is emerging that has great potential globally to open up creativity and access at the same time as it allows establishment of small-scale operations that benefit small communities by enabling them to fulfill their own immediate needs, drawing on local talent and labor, with reasonable investment costs. The trends in manufacturing technology that will contribute to establishment of new models of production include additive and other advanced manufacturing processes; small-scale multifunctional manufacturing; human-like smart robotic assistance; universally accessible, rapidly updatable, individualized education; and a dramatically expanded cyberinfrastructure. The disruptive potential of the trends in knowledge creation and production management suggests the need for a proactive approach to monitoring and governing the changes in manufacturing and society to ensure, in particular, equity of access and positive modes of human–machine interaction. DA - 2013/// PY - 2013/// DO - 10.1007/978-3-319-02204-8_7 SP - 255-285 SN - 2213-1965 ER - TY - CONF TI - Thermal phase behavior and electrochemical/physicochemical properties of carbonate and ester electrolytes with LiBF4, LiDFOB and LiBOB AU - Allen, J. L. AU - Seo, D. M. AU - McOwen, D. W. AU - Han, S. D. AU - Knight, B. A. AU - Boyle, P. D. AU - Henderson, W. A. C2 - 2013/// C3 - Lithium-ion batteries -and- non-aqueous electrolytes for lithium batteries - prime 2012 DA - 2013/// VL - 50 SP - 381-387 M1 - 26 ER - TY - CONF TI - Electrolyte solvation and ionic association: Cyclic carbonate and Ester-LiTFSI and -LiPF6 mixtures AU - Seo, D. M. AU - Allen, J. L. AU - Gardner, L. A. AU - Han, S. AU - Boyle, P. D. AU - Henderson, W. A. C2 - 2013/// C3 - Lithium-ion batteries -and- non-aqueous electrolytes for lithium batteries - prime 2012 DA - 2013/// VL - 50 SP - 375-380 M1 - 26 ER - TY - JOUR TI - Opto-Mechanical Scission of Polymer Chains in Photosensitive Diblock-Copolymer Brushes AU - Kopyshev, Alexey AU - Galvin, Casey J. AU - Genzer, Jan AU - Lomadze, Nino AU - Santer, Svetlana T2 - LANGMUIR AB - In this paper we report on an opto-mechanical scission of polymer chains within photosensitive diblock-copolymer brushes grafted to flat solid substrates. We employ surface-initiated polymerization of methylmethacrylate (MMA) and t-butyl methacrylate (tBMA) to grow diblock-copolymer brushes of poly(methylmethacrylate-b-t-butyl methacrylate) following the atom transfer polymerization (ATRP) scheme. After the synthesis, deprotection of the PtBMA block yields poly(methacrylic acid) (PMAA). To render PMMA-b-PMAA copolymers photosensitive, cationic azobenzene containing surfactants are attached to the negatively charged outer PMAA block. During irradiation with an ultraviolet (UV) interference pattern, the extent of photoisomerization of the azobenzene groups varies spatially and results in a topography change of the brush, i.e., formation of surface relief gratings (SRG). The SRG formation is accompanied by local rupturing of the polymer chains in areas from which the polymer material recedes. This opto-mechanically induced scission of the polymer chains takes place at the interfaces of the two blocks and depends strongly on the UV irradiation intensity. Our results indicate that this process may be explained by employing classical continuum fracture mechanics, which might be important for tailoring the phenomenon for applying it to poststructuring of polymer brushes. DA - 2013/11/12/ PY - 2013/11/12/ DO - 10.1021/la403241t VL - 29 IS - 45 SP - 13967-13974 SN - 0743-7463 ER - TY - JOUR TI - Durability of LDPE Nanocomposites With Clay, Silica, and Zinc Oxide II. Weatherability of the Nanocomposites AU - Redhwi, Halim Hamid AU - Siddiqui, Mohammad Nahid AU - Andrady, Anthony L. AU - Syed, Hussain T2 - POLYMER COMPOSITES AB - Three LDPE nanocomposites based on the nanoscale fillers, montmorillonite clay, silica, and zinc oxide were studied to determine if the reinforcement they imparted was accompanied by any change in the weatherability of the nanocomposite. Changes in weathering behavior were monitored in samples exposed to natural weathering outdoors over a period of 24 months of exposure. Because of superior light‐shielding afforded by the high specific surface area of nanofillers a stabilization effect might be anticipated. Alternatively chemical effects may enhance weatherability. In all three nanocomposites studied, the weatherability compared to unfilled LDPE did not significantly change due to the presence of 5 wt% of the nanofillers. The efficient reinforcement afforded by the nanofillers is not accompanied by a loss or enhancement in durability of the material. POLYM. COMPOS., 34:1878–1883, 2013. © 2013 Society of Plastics Engineers DA - 2013/11// PY - 2013/11// DO - 10.1002/pc.22594 VL - 34 IS - 11 SP - 1878-1883 SN - 1548-0569 ER - TY - JOUR TI - The theory of non-electrolyte solutions: an historical review AU - Gubbins, Keith E. T2 - MOLECULAR PHYSICS AB - Starting with the work of van der Waals in 1873, a historical review is given of theories of non-electrolyte mixtures that are based on a well-defined Hamiltonian, and thus can be tested against molecular simulation, as well as experiment. Most of the first 100 years covered here were devoted to attempts to find a successful theory of simple mixtures, culminating in the van der Waals 1-fluid theory of conformal solutions, and perturbation theories based on a hard-sphere reference fluid. The last 40 years has seen the more rapid development of theories for fluids of more complex molecules, including strongly polar liquids, chain molecules and liquids in which molecular association is important. DA - 2013/12/1/ PY - 2013/12/1/ DO - 10.1080/00268976.2013.831140 VL - 111 IS - 24 SP - 3666-3697 SN - 1362-3028 KW - solution theory history KW - polar liquids KW - perturbation theory KW - associating liquids KW - non-electrolyte solution ER - TY - JOUR TI - Semi-Batch Deoxygenation of Canola- and Lard-Derived Fatty Acids to Diesel-Range Hydrocarbons AU - Ford, Jeffrey P. AU - Thapaliya, Nirajan AU - Kelly, M. Jason AU - Roberts, William L. AU - Lamb, H. Henry T2 - ENERGY & FUELS AB - Fatty acids (FAs) derived via thermal hydrolysis of food-grade lard and canola oil were deoxygenated in the liquid phase using a commercially available 5 wt % Pd/C catalyst. Online quadrupole mass spectrometry and gas chromatography were used to monitor the effluent gases from the semi-batch stirred autoclave reactors. Stearic, oleic, and palmitic acids were employed as model compounds. A catalyst lifetime exceeding 2200 turnovers for oleic acid deoxygenation was demonstrated at 300 °C and 15 atm under 10% H2. The initial decarboxylation rate of palmitic acid under 5% H2 decreases sharply with increasing initial concentration; in contrast, the initial decarbonylation rate increases linearly, indicative of first-order kinetics. Scale-up of diesel-range hydrocarbon production was investigated by increasing the reactor vessel size, initial FA concentration, and FA/catalyst mass ratio. Lower CO2 selectivity and batch productivity were observed at the larger scales (600 and 5000 mL), primarily because of the higher initial FA concentration (67 wt %) employed. Because unsaturated FAs must be hydrogenated before deoxygenation can proceed at an appreciable rate, the additional batch time required for FA hydrogenation reduces the batch productivity for unsaturated feedstocks. Low-temperature hydrogenation of unsaturated feedstocks (using Pd/C or another less-expensive catalyst) prior to deoxygenation is recommended. DA - 2013/12// PY - 2013/12// DO - 10.1021/ef4016763 VL - 27 IS - 12 SP - 7489-7496 SN - 1520-5029 ER - TY - JOUR TI - RNA Replicon Delivery via Lipid-Complexed PRINT Protein Particles AU - Xu, Jing AU - Luft, J. Christopher AU - Yi, Xianwen AU - Tian, Shaomin AU - Owens, Gary AU - Wang, Jin AU - Johnson, Ashley AU - Berglund, Peter AU - Smith, Jonathan AU - Napier, Mary E. AU - DeSimone, Joseph M. T2 - MOLECULAR PHARMACEUTICS AB - Herein we report the development of a nonviral lipid-complexed PRINT (particle replication in nonwetting templates) protein particle system (LPP particle) for RNA replicon delivery with a view toward RNA replicon-based vaccination. Cylindrical bovine serum albumin (BSA) particles (diameter (d) 1 μm, height (h) 1 μm) loaded with RNA replicon and stabilized with a fully reversible disulfide cross-linker were fabricated using PRINT technology. Highly efficient delivery of the particles to Vero cells was achieved by complexing particles with a mixture of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) lipids. Our data suggest that (1) this lipid-complexed protein particle is a promising system for delivery of RNA replicon-based vaccines and (2) it is necessary to use a degradable cross-linker for successful delivery of RNA replicon via protein-based particles. DA - 2013/9// PY - 2013/9// DO - 10.1021/mp400190z VL - 10 IS - 9 SP - 3366-3374 SN - 1543-8384 KW - RNA replicon KW - gene delivery KW - PRINT KW - protein particle KW - lipid ER - TY - JOUR TI - Polymeric Systems Incorporating Plant Viral Nanoparticles for Tailored Release of Therapeutics AU - Honarbakhsh, Sara AU - Guenther, Richard H. AU - Willoughby, Julie A. AU - Lommel, Steven A. AU - Pourdeyhimi, Behnam T2 - ADVANCED HEALTHCARE MATERIALS AB - Therapeutic polylactide (PLA) nanofibrous matrices are fabricated by incorporating plant viral nanoparticles (PVNs) infused with fluorescent agents ethidium bromide (EtBr) and rhodamine (Rho), and cancer therapeutic doxorubicin (Dox). The native virus, Red clover necrotic mosaic virus (RCNMV), reversibly opens and closes upon exposure to the appropriate environmental stimuli. Infusing RCNMV with small molecules allows the incorporation of PVN(Active) into fibrous matrices via two methods: direct processing by in situ electrospinning of a polymer and PVNs solution or immersion of the matrix into a viral nanoparticle solution. Five organic solvents commonly in-use for electrospinning are evaluated for potential negative impact on RCNMV stability. In addition, leakage of rhodamine from the corresponding PVN(Rho) upon solvent exposure is determined. Incorporation of the PVN into the matrices are evaluated via transmission electron, scanning electron and fluorescent microscopies. Finally, the percent cumulative release of doxorubicin from both PLA nanofibers and PLA and polyethylene oxide (PEO) hybrid nanofibers demonstrate tailored release due to the incorporation of PVN(Dox) as compared to the control nanofibers with free Dox. Preliminary kinetic analysis results suggest a two-phase release profile with the first phase following a hindered Fickian transport mechanism for the release of Dox for the polymer-embedded PVNs. In contrast, the nanofiber matrices that incorporate PVNs through the immersion processing method followed a pseudo-first order kinetic transport mechanism. DA - 2013/7// PY - 2013/7// DO - 10.1002/adhm.201200434 VL - 2 IS - 7 SP - 1001-1007 SN - 2192-2659 KW - controlled release KW - drug delivery KW - nanofibers KW - plant viral nanoparticles KW - virus ER - TY - JOUR TI - Mechanisms and reactions during atomic layer deposition on polymers AU - Parsons, Gregory N. AU - Atanasov, Sarah E. AU - Dandley, Erinn C. AU - Devine, Christina K. AU - Gong, Bo AU - Jur, Jesse S. AU - Lee, Kyoungmi AU - Oldham, Christopher J. AU - Peng, Qing AU - Spagnola, Joseph C. AU - Williams, Philip S. T2 - COORDINATION CHEMISTRY REVIEWS AB - There is significant growing interest in atomic layer deposition onto polymers for barrier coatings, nanoscale templates, surface modification layers and other applications. The ability to control the reaction between ALD precursors and polymers opens new opportunities in ALD materials processing. It is well recognized that ALD on many polymers involves subsurface precursor diffusion and reaction which are not encountered during ALD on solid surfaces. This article reviews recent insights into chemical reactions that proceed during ALD on polymers, with particular focus on the common Al2O3 reaction sequence using trimethyl aluminum (TMA) and water. We highlight the role of different polymer reactive groups in film growth, and how the balance between precursor diffusion and reaction can change as deposition proceeds. As a strong Lewis acid, TMA forms adducts with Lewis base sites within the polymer, and the reactions that proceed are determined by the neighboring bond structure. Moreover, the Lewis base sites can be saturated by TMA, producing a self-limiting half-reaction within a three-dimensional polymer, analogous to a self-limiting half-reaction commonly observed during ALD on a solid planar surface. DA - 2013/12// PY - 2013/12// DO - 10.1016/j.ccr.2013.07.001 VL - 257 IS - 23-24 SP - 3323-3331 SN - 1873-3840 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000327915000012&KeyUID=WOS:000327915000012 KW - Atomic layer deposition KW - Polymers KW - Thin films KW - Inorganic coatings KW - Al2O3 ER - TY - JOUR TI - Functional Consequences of the Open Distal Pocket of Dehaloperoxidase-Hemoglobin Observed by Time-Resolved X-ray Crystallography AU - Zhao, Junjie AU - Srajer, Vukica AU - Franzen, Stefan T2 - BIOCHEMISTRY AB - Using time-resolved X-ray crystallography, we contrast a bifunctional dehaloperoxidase-hemoglobin (DHP) with previously studied examples of myoglobin and hemoglobin to understand the functional role of the distal pocket of globins. One key functional difference between DHP and other globins is the requirement that H2O2 enter the distal pocket of oxyferrous DHP to displace O2 from the heme Fe atom and thereby activate the heme for the peroxidase function. The open architecture of DHP permits more than one molecule to simultaneously enter the distal pocket of the protein above the heme to facilitate the unique peroxidase cycle starting from the oxyferrous state. The time-resolved X-ray data show that the distal pocket of DHP lacks a protein valve found in the two other globins that have been studied previously. The photolyzed CO ligand trajectory in DHP does not have a docking site; rather, the CO moves immediately to the Xe-binding site. From there, CO can escape but can also recombine an order of magnitude more rapidly than in other globins. The contrast with DHP dynamics and function more precisely defines the functional role of the multiple conformational states of myoglobin. Taken together with the high reduction potential of DHP, the open distal site helps to explain how a globin can also function as a peroxidase. DA - 2013/11/12/ PY - 2013/11/12/ DO - 10.1021/bi401118q VL - 52 IS - 45 SP - 7943-7950 SN - 0006-2960 ER - TY - JOUR TI - Educational Practice and Educational Research in Engineering: Partners, Antagonists, or Ships Passing in the Night? AU - Felder, Richard M. AU - Hadgraft, Roger G. T2 - JOURNAL OF ENGINEERING EDUCATION AB - Journal of Engineering EducationVolume 102, Issue 3 p. 339-345 Guest Editorial Educational Practice and Educational Research in Engineering: Partners, Antagonists, or Ships Passing in the Night? Richard M. Felder, Richard M. Felder North Carolina State UniversitySearch for more papers by this authorRoger G. Hadgraft, Roger G. Hadgraft RMIT University, Melbourne, AustraliaSearch for more papers by this author Richard M. Felder, Richard M. Felder North Carolina State UniversitySearch for more papers by this authorRoger G. Hadgraft, Roger G. Hadgraft RMIT University, Melbourne, AustraliaSearch for more papers by this author First published: 17 October 2013 https://doi.org/10.1002/jee.20015Citations: 21Read 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 Citing Literature Volume102, Issue3July 2013Pages 339-345 RelatedInformation DA - 2013/7// PY - 2013/7// DO - 10.1002/jee.20015 VL - 102 IS - 3 SP - 339-345 SN - 2168-9830 ER - TY - JOUR TI - Crossing the divide between homogeneous and heterogeneous catalysis in water oxidation AU - Vannucci, Aaron K. AU - Alibabaei, Leila AU - Losego, Mark D. AU - Concepcion, Javier J. AU - Kalanyan, Berc AU - Parsons, Gregory N. AU - Meyer, Thomas J. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Enhancing the surface binding stability of chromophores, catalysts, and chromophore-catalyst assemblies attached to metal oxide surfaces is an important element in furthering the development of dye sensitized solar cells, photoelectrosynthesis cells, and interfacial molecular catalysis. Phosphonate-derivatized catalysts and molecular assemblies provide a basis for sustained water oxidation on these surfaces in acidic solution but are unstable toward hydrolysis and loss from surfaces as the pH is increased. Here, we report enhanced surface binding stability of a phosphonate-derivatized water oxidation catalyst over a wide pH range (1-12) by atomic layer deposition of an overlayer of TiO2. Increased stability of surface binding, and the reactivity of the bound catalyst, provides a hybrid approach to heterogeneous catalysis combining the advantages of systematic modifications possible by chemical synthesis with heterogeneous reactivity. For the surface-stabilized catalyst, greatly enhanced rates of water oxidation are observed upon addition of buffer bases -H2PO(-)(4)/HPO(2-)(4), B(OH)3/B(OH)2 O-, HPO(2-)4 /PO(3-)(4) - and with a pathway identified in which O-atom transfer to OH(-) occurs with a rate constant increase of 10(6) compared to water oxidation in acid. DA - 2013/12/24/ PY - 2013/12/24/ DO - 10.1073/pnas.1319832110 VL - 110 IS - 52 SP - 20918-20922 SN - 0027-8424 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000328858800030&KeyUID=WOS:000328858800030 KW - electrocatalysis KW - surface stabilization ER - TY - JOUR TI - Bioactive Cellulose Nanofibrils for Specific Human IgG Binding AU - Zhang, Yanxia AU - Carbonell, Ruben G. AU - Rojas, Orlando J. T2 - BIOMACROMOLECULES AB - Bioactive films were produced by conjugation of a short peptide onto modified cellulose nanofibrils (CNF). Specifically, a hydrophilic copolymer, poly(2-aminoethyl methacrylate hydrochloride-co-2-hydroxyethylmethacrylate) (poly(AMA-co-HEMA)), was grafted via surface initiated polymerization from an initiator coupled to CNF. The poly(AMA-co-HEMA) was used as a spacer and support layer for immobilization of the peptide, acetylated-HWRGWVA, which has specific affinity with human immunoglobulin G (hIgG). Two methods for peptide grafting were compared: modification of CNF in aqueous suspension followed by assembly into a bioactive film and peptide grafting on a preformed CNF film. The CNF-based networks were examined on solid supports via atomic force microscopy (AFM) and extreme resolution imaging with ultralow electron landing energies (scanning low energy electron microscopy). The specific binding capability of hIgG and nonspecific protein resistance of the resultant peptide-modified CNF were evaluated by using quartz crystal microgravimetry (QCM). The effects of initiator concentration and thickness of poly(AMA-co-HEMA) layer on hIgG adsorption were investigated in the developed systems, which exhibited high signal-to-noise response. DA - 2013/12// PY - 2013/12// DO - 10.1021/bm4007979 VL - 14 IS - 12 SP - 4161-4168 SN - 1526-4602 ER - TY - JOUR TI - Activated carbon from biochar: Influence of its physicochemical properties on the sorption characteristics of phenanthrene AU - Park, Junyeong AU - Hung, Ivan AU - Gan, Zhehong AU - Rojas, Orlando J. AU - Lim, Kwang Hun AU - Park, Sunkyu T2 - BIORESOURCE TECHNOLOGY AB - The relationship between physicochemical properties of biochar-based activated carbons and its adsorption was investigated using an aromatic model compound, phenanthrene. Solid-state 13C NMR analysis indicated more condensed aromatic structures when pyrolysis temperature increased or after activation process induced. The increasing aromaticity and non-protonated carbon fraction of the activated biochar treated at 300 °C amounted to 14.7% and 24.0%, respectively, compared to 7.4% and 4.4% for biochar treated at 700 °C. The surface area and pore volume were reduced with the increase in pyrolysis temperature, but increased after activation. Surface characteristics correlated with the initial sorption rate and equilibrium concentration of phenanthrene, but not with the aromaticity. Solid-state 2H NMR for phenanthrene-d10 saturated activated biochars, however, showed substantial difference in molecular mobility, which might be due to the high aromaticity of the activated biochars. Overall, these results provide an opportunity to manipulate the characteristics of biomass-based adsorbents based on the application needs. DA - 2013/12// PY - 2013/12// DO - 10.1016/j.biortech.2013.09.085 VL - 149 SP - 383-389 SN - 1873-2976 KW - Biochar KW - Solid-state NMR KW - Activation Activated biochar KW - Phenanthrene adsorption ER - TY - JOUR TI - Thermomechanical Properties of Lignin-Based Electrospun Nanofibers and Films Reinforced with Cellulose Nanocrystals: A Dynamic Mechanical and Nanoindentation Study AU - Ago, Mariko AU - Jakes, Joseph E. AU - Rojas, Orlando J. T2 - ACS APPLIED MATERIALS & INTERFACES AB - We produced defect-free electrospun fibers from aqueous dispersions of lignin, poly(vinyl alcohol) (PVA), and cellulose nanocrystals (CNCs), which were used as reinforcing nanoparticles. The thermomechanical performance of the lignin-based electrospun fibers and the spin-coated thin films was improved when they were embedded with CNCs. Isochronal dynamic mechanical analysis (DMA) was used to assess the viscoelastic properties of the lignin:PVA electrospun fiber mats loaded with CNCs. DMA revealed that α relaxation processes became less prominent with an increased lignin content, an effect that correlated with the loss tangent (tan δ = E″/E') and α peak (Tg) that shifted to higher temperatures. This can be ascribed to the restraint of the segmental motion of PVA in the amorphous regions caused by strong intermolecular interactions. The reinforcing effect and high humidity stability attained by addition of CNCs (5, 10, or 15 wt %) in the multicomponent fiber mats were revealed. Nanoindentation was performed to assess the elastic modulus and hardness of as-prepared and cross-section surfaces of spin-coated lignin:PVA (75:25) films loaded with CNC. The properties of the two surfaces differed, and only the trend in cross-section elastic modulus correlated with DMA results. After addition of 5 wt % CNCs, both the DMA and nanoindentation elastic modulus remained constant, while after addition of 15 wt % CNCs, both increased substantially. An indentation size effect was observed in the nanoindentation hardness, and the results provided insight into the effect of addition of CNCs on the microphysical processes controlling the yield behavior in the composites. DA - 2013/11/27/ PY - 2013/11/27/ DO - 10.1021/am403451w VL - 5 IS - 22 SP - 11768-11776 SN - 1944-8252 KW - cellulose nanocrystals KW - lignin KW - nanofibers KW - electrospinning KW - dynamic mechanical analysis KW - nanoindentation KW - thermomechanical properties KW - lignin films ER - TY - JOUR TI - Solar water splitting in a molecular photoelectrochemical cell AU - Alibabaei, Leila AU - Brennaman, M. Kyle AU - Norris, Michael R. AU - Kalanyan, Berc AU - Song, Wenjing AU - Losego, Mark D. AU - Concepcion, Javier J. AU - Binstead, Robert A. AU - Parsons, Gregory N. AU - Meyer, Thomas J. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Artificial photosynthesis and the production of solar fuels could be a key element in a future renewable energy economy providing a solution to the energy storage problem in solar energy conversion. We describe a hybrid strategy for solar water splitting based on a dye sensitized photoelectrosynthesis cell. It uses a derivatized, core-shell nanostructured photoanode with the core a high surface area conductive metal oxide film--indium tin oxide or antimony tin oxide--coated with a thin outer shell of TiO2 formed by atomic layer deposition. A "chromophore-catalyst assembly" 1, [(PO3H2)2bpy)2Ru(4-Mebpy-4-bimpy)Rub(tpy)(OH2)](4+), which combines both light absorber and water oxidation catalyst in a single molecule, was attached to the TiO2 shell. Visible photolysis of the resulting core-shell assembly structure with a Pt cathode resulted in water splitting into hydrogen and oxygen with an absorbed photon conversion efficiency of 4.4% at peak photocurrent. DA - 2013/12/10/ PY - 2013/12/10/ DO - 10.1073/pnas.1319628110 VL - 110 IS - 50 SP - 20008-20013 SN - 0027-8424 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000328061700026&KeyUID=WOS:000328061700026 ER - TY - JOUR TI - Scalable Manufacture of Built-to-Order Nanomedicine: Spray-Assisted Layer-by-Layer Functionalization of PRINT Nanoparticles AU - Morton, Stephen W. AU - Herlihy, Kevin P. AU - Shopsowitz, Kevin E. AU - Deng, Zhou J. AU - Chu, Kevin S. AU - Bowerman, Charles J. AU - DeSimone, Joseph M. AU - Hammond, Paula T. T2 - ADVANCED MATERIALS AB - Scalable methods, PRINT particle fabrication, and spray-assisted Layer-by-Layer deposition are combined to generate uniform and functional nanotechnologies with precise control over composition, size, shape, and surface functionality. A modular and tunable approach towards design of built-to-order nanoparticle systems, spray coating on PRINT particles is demonstrated to achieve technologies capable of targeted interactions with cancer cells for applications in drug delivery. DA - 2013/9/14/ PY - 2013/9/14/ DO - 10.1002/adma.201302025 VL - 25 IS - 34 SP - 4707-4713 SN - 1521-4095 KW - core KW - shell nanoparticles KW - thin films KW - nanoimprinting KW - nanomedicine ER - TY - JOUR TI - Rapidly-Dissolvable Microneedle Patches Via a Highly Scalable and Reproducible Soft Lithography Approach AU - Moga, Katherine A. AU - Bickford, Lissett R. AU - Geil, Robert D. AU - Dunn, Stuart S. AU - Pandya, Ashish A. AU - Wang, Yapei AU - Fain, John H. AU - Archuleta, Christine F. AU - Adrian T. O'Neill, AU - DeSimone, Joseph M. T2 - ADVANCED MATERIALS AB - Microneedle devices for transdermal drug delivery have recently become an attractive method to overcome the diffusion-limiting epidermis and effectively transport therapeutics to the body. Here, we demonstrate the fabrication of highly reproducible and completely dissolvable polymer microneedles on flexible water-soluble substrates. These biocompatible microneedles (made by using a soft lithography process known as PRINT) showed efficacy in piercing both murine and human skin samples and delivering a fluorescent drug surrogate to the tissue. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. DA - 2013/9// PY - 2013/9// DO - 10.1002/adma.201300526 VL - 25 IS - 36 SP - 5060-5066 SN - 1521-4095 KW - microneedles KW - microprojections KW - PRINT KW - soft lithography KW - drug delivery ER - TY - JOUR TI - Influence of solvent on ion aggregation and transport in PY15TFSI ionic liquid-aprotic solvent mixtures AU - Borodin, O. AU - Henderson, W. A. AU - Fox, E. T. AU - Berman, M. AU - Gobet, M. AU - Greenbaum, S. T2 - Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces & Biophysical DA - 2013/// PY - 2013/// VL - 117 IS - 36 SP - 10581-10588 ER - TY - JOUR TI - Genetically encoded light-activated transcription for spatiotemporal control of gene expression and gene silencing in mammalian cells AU - Hemphill, J. AU - Chou, C. J. AU - Chin, J. W. AU - Deiters, A. T2 - Journal of the American Chemical Society AB - Photocaging provides a method to spatially and temporally control biological function and gene expression with high resolution. Proteins can be photochemically controlled through the site-specific installation of caging groups on amino acid side chains that are essential for protein function. The photocaging of a synthetic gene network using unnatural amino acid mutagenesis in mammalian cells was demonstrated with an engineered bacteriophage RNA polymerase. A caged T7 RNA polymerase was expressed in cells with an expanded genetic code and used in the photochemical activation of genes under control of an orthogonal T7 promoter, demonstrating tight spatial and temporal control. The synthetic gene expression system was validated with two reporter genes (luciferase and EGFP) and applied to the light-triggered transcription of short hairpin RNA constructs for the induction of RNA interference. DA - 2013/// PY - 2013/// DO - 10.1021/ja4051026 VL - 135 IS - 36 SP - 13433-13439 ER - TY - JOUR TI - Controllable atomistic graphene oxide model and its application in hydrogen sulfide removal AU - Huang, Liangliang AU - Seredych, Mykola AU - Bandosz, Teresa J. AU - van Duin, Adri C. T. AU - Lu, Xiaohua AU - Gubbins, Keith E. T2 - The Journal of Chemical Physics AB - The determination of an atomistic graphene oxide (GO) model has been challenging due to the structural dependence on different synthesis methods. In this work we combine temperature-programmed molecular dynamics simulation techniques and the ReaxFF reactive force field to generate realistic atomistic GO structures. By grafting a mixture of epoxy and hydroxyl groups to the basal graphene surface and fine-tuning their initial concentrations, we produce in a controllable manner the GO structures with different functional groups and defects. The models agree with structural experimental data and with other ab initio quantum calculations. Using the generated atomistic models, we perform reactive adsorption calculations for H2S and H2O/H2S mixtures on GO materials and compare the results with experiment. We find that H2S molecules dissociate on the carbonyl functional groups, and H2O, CO2, and CO molecules are released as reaction products from the GO surface. The calculation reveals that for the H2O/H2S mixtures, H2O molecules are preferentially adsorbed to the carbonyl sites and block the potential active sites for H2S decomposition. The calculation agrees well with the experiments. The methodology and the procedure applied in this work open a new door to the theoretical studies of GO and can be extended to the research on other amorphous materials. DA - 2013/11/21/ PY - 2013/11/21/ DO - 10.1063/1.4832039 VL - 139 IS - 19 SP - 194707 J2 - The Journal of Chemical Physics LA - en OP - SN - 0021-9606 1089-7690 UR - http://dx.doi.org/10.1063/1.4832039 DB - Crossref ER - TY - JOUR TI - Aligned Carbon Nanotube-Silicon Sheets: A Novel Nano-architecture for Flexible Lithium Ion Battery Electrodes AU - Fu, Kun AU - Yildiz, Ozkan AU - Bhanushali, Hardik AU - Wang, Yongxin AU - Stano, Kelly AU - Xue, Leigang AU - Zhang, Xiangwu AU - Bradford, Philip D. T2 - ADVANCED MATERIALS AB - Aligned carbon nanotube sheets provide an engineered scaffold for the deposition of a silicon active material for lithium ion battery anodes. The sheets are low-density, allowing uniform deposition of silicon thin films while the alignment allows unconstrained volumetric expansion of the silicon, facilitating stable cycling performance. The flat sheet morphology is desirable for battery construction. DA - 2013/9// PY - 2013/9// DO - 10.1002/adma.201301920 VL - 25 IS - 36 SP - 5109-5114 SN - 1521-4095 UR - https://publons.com/publon/7178364/ KW - silicon KW - carbon nanotube KW - super-aligned KW - anode KW - lithium ion batteries ER - TY - JOUR TI - A simple method to encapsulate SnSb nanoparticles into hollow carbon nanofibers with superior lithium-ion storage capability AU - Xue, Leigang AU - Xia, Xin AU - Tucker, Telpriore AU - Fu, Kun AU - Zhang, Shu AU - Li, Shuli AU - Zhang, Xiangwu T2 - JOURNAL OF MATERIALS CHEMISTRY A AB - The practical use of high-capacity anodes in lithium-ion batteries generally suffers from significant volume changes upon lithium insertion and extraction. The volume changes induce cracks and loss of inter-particle electronic contact in the electrode, resulting in rapid capacity decay. The use of fiber-like materials to prevent cracks and accommodate volume changes is widely observed in many animal and human activities. Birds mix grass and feathers into mud to build nests, and humans in ancient times blended straw with mud to produce adobe bricks for housing construction. In view of this point, this research designed a porous nanofiber structure to resolve the unstable structure problem of anode materials. The three-dimensional network structure composed of nanofibers provides a highly elastic matrix to accommodate the volume changes of high-capacity Sn and Sb particles and pores around the active particles, induced by CO2 evolution, serve as an additional buffer zone for the volume changes. This unique structure prepared by using a new SnSb alloy precursor and a simple electrospinning technique leads to excellent lithium storage performance in terms of energy density, cycling stability, and rate capability. DA - 2013/// PY - 2013/// DO - 10.1039/c3ta12921g VL - 1 IS - 44 SP - 13807-13813 SN - 2050-7496 UR - https://publons.com/publon/7178344/ ER - TY - JOUR TI - 3D Printing of Free Standing Liquid Metal Microstructures AU - Ladd, Collin AU - So, Ju-Hee AU - Muth, John AU - Dickey, Michael D. T2 - ADVANCED MATERIALS AB - This paper describes a method to direct-write 3D liquid metal microcomponents at room temperature. The thin oxide layer on the surface of the metal allows the formation of mechanically stable structures strong enough to stand against gravity and the large surface tension of the liquid. The method is capable of printing wires, arrays of spheres, arches, and interconnects. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. DA - 2013/9// PY - 2013/9// DO - 10.1002/adma.201301400 VL - 25 IS - 36 SP - 5081-5085 SN - 1521-4095 KW - direct-write KW - 3D printing KW - liquid metal KW - egain KW - stretchable electronics ER - TY - JOUR TI - Three-dimensional self-assembled photonic crystals with high temperature stability for thermal emission modification AU - Arpin, Kevin A. AU - Losego, Mark D. AU - Cloud, Andrew N. AU - Ning, Hailong AU - Mallek, Justin AU - Sergeant, Nicholas P. AU - Zhu, Linxiao AU - Yu, Zongfu AU - Kalanyan, Berc AU - Parsons, Gregory N. AU - Girolami, Gregory S. AU - Abelson, John R. AU - Fan, Shanhui AU - Braun, Paul V. T2 - NATURE COMMUNICATIONS AB - Selective thermal emission in a useful range of energies from a material operating at high temperatures is required for effective solar thermophotovoltaic energy conversion. Three-dimensional metallic photonic crystals can exhibit spectral emissivity that is modified compared with the emissivity of unstructured metals, resulting in an emission spectrum useful for solar thermophotovoltaics. However, retention of the three-dimensional mesostructure at high temperatures remains a significant challenge. Here we utilize self-assembled templates to fabricate high-quality tungsten photonic crystals that demonstrate unprecedented thermal stability up to at least 1,400 °C and modified thermal emission at solar thermophotovoltaic operating temperatures. We also obtain comparable thermal and optical results using a photonic crystal comprising a previously unstudied material, hafnium diboride, suggesting that refractory metallic ceramic materials are viable candidates for photonic crystal-based solar thermophotovoltaic devices and should be more extensively studied. DA - 2013/10// PY - 2013/10// DO - 10.1038/ncomms3630 VL - 4 SP - SN - 2041-1723 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000326472200019&KeyUID=WOS:000326472200019 ER - TY - JOUR TI - The Regulatory Implications of Hydroquinone for the Multifunctional Enzyme Dehaloperoxidase-Hemoglobin from Amphitrite ornata AU - Zhao, Jing AU - Zhao, Junjie AU - Franzen, Stefan T2 - JOURNAL OF PHYSICAL CHEMISTRY B AB - Hydroquinone (H2Q) has been observed to compete with the oxidation of substrates 2,4,6-tribromophenol (2,4,6-TBP) and 2,4,6-trichlorophenol (2,4,6-TCP) catalyzed by the dehaloperoxidase-hemoglobin (DHP) from Amphitrite ornata in the presence of H2O2. This competition is observed as a lag phase during which H2Q is preferentially oxidized to 1,4-benzoquinone (1,4-BQ) while totally inhibiting either 2,4,6-TBP or 2,4,6-TCP oxidation. The inhibition by H2Q is distinct from that of the native competitive inhibitor 4-bromophenol (4-BP) since H2Q is itself oxidized and its product 1,4-BQ is not an inhibitor. Thus, once H2Q is completely consumed, the inhibition is removed, and normal substrate turnover is initiated, which explains the lag phase. To probe the mechanism of lag phase, the reactions between H2Q and DHP were both studied both in the presence and in the absence of H2O2. The reversible reactions between ferric/oxyferrous DHP A and H2Q/1,4-BQ are shown to involve a proton-coupled electron transfer (PCET) mechanism, where the distal histidine His55 serves as the proton acceptor. The pKa of the distal histidine His55 has been determined by resonance Raman spectroscopy in order to corroborate its involvement in this mechanism. Consistent with the proposed mechanism, kinetic assays have shown that H2Q serves as a substrate for DHP that follows the Michaelis–Menten kinetics. Unlike H2Q, the product 1,4-BQ has a relatively large Ki value and therefore has negligible inhibition. This study sheds light on understanding the difference between substrate and inhibitor binding sites and regulatory implication for the peroxidase and oxygen-transporter functions in DHP. It also provides information on PCET in DHP, which is important for resolving the switching between the ferric peroxidase catalytic function and the ferrous oxygen transport function. DA - 2013/11/28/ PY - 2013/11/28/ DO - 10.1021/jp407663n VL - 117 IS - 47 SP - 14615-14624 SN - 1520-6106 ER - TY - JOUR TI - Stabilizing molecular sensitizers in aqueous environs AU - Losego, M. D. AU - Hanson, K. T2 - Nano Energy DA - 2013/// PY - 2013/// VL - 2 IS - 5 SP - 1067-1069 ER - TY - JOUR TI - Solid Electrolyte Interphase on Lithium-Ion Carbon Nanofiber Electrodes by Atomic and Molecular Layer Deposition AU - Loebl, Andrew J. AU - Oldham, Christopher J. AU - Devine, Christina K. AU - Gong, Bo AU - Atanasov, Sarah E. AU - Parsons, Gregory N. AU - Fedkiw, Peter S. T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - Carbon nanofibers were coated with Al2O3 by atomic layer deposition (ALD) or with an alumina-organic hybrid thin film layer by molecular layer deposition (MLD) to produce an artificial solid electrolyte interphase (SEI) prior to use as a lithium-ion battery electrode. The elemental composition of the materials was investigated using energy dispersive X-ray spectroscopy (EDX) and inductively coupled plasma mass spectrometry (ICP-MS). A coating of ten Al2O3 layers reduced the lithium lost to the SEI formation from 359 to 291 mAh/g (24%) during the first charge. These same cells possessed 370 mAh/g of stable reversible capacity when tested at low current density (25 mA/g), similar to uncoated material. At increased currents, Al2O3 films of either ten or twenty layers lowered the capacity retention when compared with uncoated materials. When compared to the ALD material, films deposited by MLD resulted in less improvement to reversible capacity and a greater loss of reversible capacity. These results indicate the use of ALD to create a new electrode surface and mitigate the Li losses to SEI formation may be a viable method of addressing the challenges associated with high-surface area electrode materials. DA - 2013/// PY - 2013/// DO - 10.1149/2.020311jes VL - 160 IS - 11 SP - A1971-A1978 SN - 1945-7111 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000326905000006&KeyUID=WOS:000326905000006 ER - TY - JOUR TI - Reversible cyclic peptide libraries for the discovery of affinity ligands AU - Menegatti, S. AU - Ward, K. L. AU - Naik, A. D. AU - Kish, W. S. AU - Blackburn, R. K. AU - Carbonell, R. G. T2 - Analytical Chemistry AB - A novel strategy is presented for the identification of cyclic peptide ligands from combinatorial libraries of reversible cyclic depsipeptides. A method for the solid-phase synthesis of individual cyclic depsipeptides and combinatorial libraries of these compounds is proposed, which employs lactic acid (Lact) and the dipeptide ester (Nα-Ac)-Ser(Ala)- as linkers for dilactonization. Upon alkaline treatment of the beads selected by screening a model library, the cyclic depsipeptides are linearized and released from the solid support to the liquid phase, to be sequenced via single-step tandem mass spectrometry (MS/MS). The protocol presented for library synthesis provides for wide structural diversity. Two model sequences, VVWVVK and AAWAAR, were chosen to present different structural examples for depsipeptide libraries and demonstrate the process of sequence determination by mass spectrometry. Further, a case study using the IgG binding cyclic depsipeptide cyclo[(Nα-Ac)-S(A)-RWHYFK-Lact-E] is presented to demonstrate the process of library screening and sequence determination on the selected beads. Finally, a method is shown for synthesis of the irreversible cyclic peptide corresponding to the proposed depsipeptide structure, to make the ligand stable to the aqueous acid and alkaline conditions encountered in affinity chromatographic applications. The cyclic peptide ligand was synthesized on a poly(methacrylate) resin and used for chromatographic binding of the target IgG. DA - 2013/// PY - 2013/// DO - 10.1021/ac401954k VL - 85 IS - 19 SP - 9229–9237 ER - TY - PCOMM TI - Reply to Perkin et al.: Experimental observations demonstrate that ionic liquids form both bound (Stern) and diffuse electric double layers AU - Gebbie, M. A. AU - Valtiner, M. AU - Banquy, X. AU - Henderson, W. A. AU - Israelachvili, J. N. DA - 2013/// PY - 2013/// SP - E4122-4122 ER - TY - JOUR TI - Preservation of Cell Viability and Protein Conformation on Immobilization within Nanofibers via Electrospinning Functionalized Yeast AU - Canbolat, M. Fatih AU - Gera, Nimish AU - Tang, Christina AU - Monian, Brinda AU - Rao, Balaji M. AU - Pourdeyhimi, Behnam AU - Khan, Saad A. T2 - ACS APPLIED MATERIALS & INTERFACES AB - We investigate the immobilization of a model system of functionalized yeast that surface-display enhanced green fluorescent protein (eGFP) within chemically crosslinked polyvinyl alcohol (PVA) nanofibers. Yeast is incorporated into water insoluble nanofibrous materials by direct electrospinning with PVA followed by vapor phase chemical crosslinking of the polymer. Incorporation of yeast into the fibers is confirmed by elemental analysis and the viability is indicated by live/dead staining. Following electrospinning and crosslinking, we confirm that the yeast maintains its viability as well as the ability to express eGFP in the correct conformation. This method of processing functionalized yeast may thus be a powerful tool in the direct immobilization of properly folded, active enzymes within electrospun nanofibers with potential applications in biocatalysis. DA - 2013/10/9/ PY - 2013/10/9/ DO - 10.1021/am4022768 VL - 5 IS - 19 SP - 9349-9354 SN - 1944-8252 KW - electrospinning KW - nanofiber KW - protein KW - biocatalyst immobilization KW - yeast surface display ER - TY - JOUR TI - Potential of ozonolysis as a pretreatment for energy grasses AU - Panneerselvam, Anushadevi AU - Sharma-Shivappa, Ratna R. AU - Kolar, Praveen AU - Ranney, Thomas AU - Peretti, Steven T2 - BIORESOURCE TECHNOLOGY AB - This study investigated the effect of ozonolysis on Miscanthus × giganteus, Miscanthus sinensis 'Gracillimus', Saccharum arundinaceum and Saccharum ravennae, collectively referred to as 'energy grasses'. Studies were conducted at three different ozone concentrations (40, 50 and 58 mg/l) using two ozone flow configurations - uni-directional and reversed flow. Pretreatment conditions for each variety were optimized based on lignin content and glucan recovery in ozonated solids. Results showed that ozonolysis was effective in removing up to 59.9% lignin without cellulose degradation. However, subsequent hydrolysis of pretreated solids with Cellic® CTec2 at 0.06 g/g raw biomass provided glucan conversion lower than untreated samples suggesting enzyme inhibition by lignin degradation products formed during ozonolysis. Future studies investigating hydrolysis efficiency of washed pretreated solids with higher enzyme loadings are therefore warranted to optimize the hydrolysis process and make it functionally feasible. DA - 2013/11// PY - 2013/11// DO - 10.1016/j.biortech.2013.08.129 VL - 148 SP - 242-248 SN - 1873-2976 KW - Miscanthus KW - Saccharum KW - Optimization KW - Flow configuration KW - Enzymatic hydrolysis ER - TY - JOUR TI - Polymer Nanocomposites Containing Carbon Nanofibers as Soft Printable Sensors Exhibiting Strain-Reversible Piezoresistivity AU - Toprakci, Hatice A. K. AU - Kalanadhabhatla, Saral K. AU - Spontak, Richard J. AU - Ghosh, Tushar K. T2 - ADVANCED FUNCTIONAL MATERIALS AB - Abstract Designed as flexible and extendable conductive print media for pervasive computing as strain sensors, nanocomposites composed of a plasticized thermoplastic or a cross‐linked elastomer and containing carbon nanofibers at concentrations just above the percolation threshold are observed to exhibit a uniquely strain‐reversible piezoresistive response upon application of quasi‐static tensile strain. At small strain levels, the electrical resistance of these nanocomposites reduces with increasing strain, indicative of negative piezoresistivity. Beyond a critical strain, however, the resistance reverses and increases with increasing strain, revealing the existence of a negative‐to‐positive piezoresistivity transition that is fully strain‐reversible and repeatable upon strain cycling. These characteristics imply that the nanocomposite morphologies are highly stable with little evidence of mechanical hysteresis. The mechanism underlying this transition is attributed to reorientation of high‐aspect‐ratio nanofibers (initially homogeneously dispersed) at low strains, followed by separation at high strains. While deposition of these nanocomposites as robust print coatings on textile fabric alters the percolation threshold, strain‐reversible piezoresistivity is retained, confirming that they are suitable as printable strain sensors. DA - 2013/11/26/ PY - 2013/11/26/ DO - 10.1002/adfm.201300034 VL - 23 IS - 44 SP - 5536-5542 SN - 1616-3028 KW - electronic textiles KW - piezoresistive nanocomposites KW - printable sensors KW - percolative elastomers KW - pervasive computing ER - TY - JOUR TI - Parameter study and characterization for polyacrylonitrile nanofibers fabricated via centrifugal spinning process AU - Lu, Yao AU - Li, Ying AU - Zhang, Shu AU - Xu, Guanjie AU - Fu, Kun AU - Lee, Hun AU - Zhang, Xiangwu T2 - EUROPEAN POLYMER JOURNAL AB - Electrospinning is currently the most popular method for producing polymer nanofibers. However, the low production rate and safety concern limit the practical use of electrospinning as a cost-effective nanofiber fabrication approach. Herein, we present a novel and simple centrifugal spinning technology that extrudes nanofibers from polymer solutions by using a high-speed rotary and perforated spinneret. Polyacrylonitrile (PAN) nanofibers were prepared by selectively varying parameters that can affect solution intrinsic properties and operational conditions. The resultant PAN nanofibers were characterized by SEM, and XRD. The correlation between fiber morphology and processing conditions was established. Results demonstrated that the fiber morphology can be easily manipulated by controlling the spinning parameters and the centrifugal spinning process is a facile approach for fabricating polymer nanofibers in a large-scale and low-cost fashion. DA - 2013/12// PY - 2013/12// DO - 10.1016/j.eurpolymj.2013.09.017 VL - 49 IS - 12 SP - 3834-3845 SN - 1873-1945 UR - https://publons.com/publon/7178360/ KW - Nanofibers KW - Centrifugal spinning KW - Electrospinning KW - Polyacrylonitrile KW - Diameter KW - Crystallinity ER - TY - CONF TI - Organic surface modifications on silicone elastomers: Impact on moisture vapor permeability and surface energy dynamics AU - Grewal, R. AU - Willoughby, J. A. AB - The purpose of this study was to observe the effects of organic surface modifications on silicone elastomers with respect to moisture vapor permeability properties as a function of both grafted moiety functionality and packing density. We utilized chemical vapor deposition and mechanical manipulation of the elastomer to deposit (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane and 3-aminopropyltrimethoxysilane. As expected, the chemical vapor deposition of both species altered the chemistry of the elastomer surface to more hydrophobic for the fluorinated silane and more hydrophilic for the amino - terminated silane in the absence of mechanical elongation during the modification. As previously demonstrated, increasing the packing density of the silanes by increasing the degree of tension on the substrate during activiation and deposition, resulted in an increase in the contact angle of water. This turned out to be true even for the hydrophilic species. In all modified samples, the moisture vapor permeability (MVP) decreased by about 50% and is attributed to the ultraviolet/ ozone activation step that created a silica-like layer. Despite the reduction in MVP, the modified elastomer films are still considered to have a high moisture vapor permeability on the order of 5·10-1 g·mm/m2·hr·kPa. C2 - 2013/// C3 - Progress in silicones and silicone-modified materials DA - 2013/// DO - 10.1021/bk-2013-1154.ch009 VL - 1154 SP - 113-132 ER - TY - JOUR TI - On the Calculation of Solid-Fluid Contact Angles from Molecular Dynamics AU - Santiso, Erik E. AU - Herdes, Carmelo AU - Mueller, Erich A. T2 - ENTROPY AB - A methodology for the determination of the solid-fluid contact angle, to be employed within molecular dynamics (MD) simulations, is developed and systematically applied. The calculation of the contact angle of a fluid drop on a given surface, averaged over an equilibrated MD trajectory, is divided in three main steps: (i) the determination of the fluid molecules that constitute the interface, (ii) the treatment of the interfacial molecules as a point cloud data set to define a geometric surface, using surface meshing techniques to compute the surface normals from the mesh, (iii) the collection and averaging of the interface normals collected from the post-processing of the MD trajectory. The average vector thus found is used to calculate the Cassie contact angle (i.e., the arccosine of the averaged normal z-component). As an example we explore the effect of the size of a drop of water on the observed solid-fluid contact angle. A single coarse-grained bead representing two water molecules and parameterized using the SAFT-γ Mie equation of state (EoS) is employed, meanwhile the solid surfaces are mimicked using integrated potentials. The contact angle is seen to be a strong function of the system size for small nano-droplets. The thermodynamic limit, corresponding to the infinite size (macroscopic) drop is only truly recovered when using an excess of half a million water coarse-grained beads and/or a drop radius of over 26 nm. DA - 2013/9// PY - 2013/9// DO - 10.3390/e15093734 VL - 15 IS - 9 SP - 3734-3745 SN - 1099-4300 KW - cloud data set KW - interfacial tension KW - coarse-graining KW - water KW - line tension KW - graphene ER - TY - JOUR TI - Nanoscale distribution and segregation of midblock-selective co-penetrants in ABA triblock copolymer lamellae AU - Piephoff, D. Evan AU - Rasmussen, Kim O. AU - Spontak, Richard J. T2 - RSC ADVANCES AB - In addition to their attractive and tunable macroscopic properties, microphase-ordered block copolymers serve as model systems capable of providing fundamental insight into the thermodynamic factors that govern the arrangement of spatially-confined molecules in soft, nanostructured environments. Of particular interest in this study is the spatial distribution of co-penetrant molecules in the design of dense polymeric materials intended for use as gas-separation membranes or responsive sensors. Here, we employ self-consistent field theory to examine the spatial distributions of two midblock-selective co-penetrants in ordered triblock copolymers exhibiting the lamellar morphology. Our results establish how differences in block copolymer incompatibility and penetrant selectivity, size and concentration affect the spatial distributions of the penetrant species, and reveal the extent to which macroscopically miscible penetrants spatially segregate due to nanoscale confinement. DA - 2013/// PY - 2013/// DO - 10.1039/c3ra44253e VL - 3 IS - 45 SP - 22863-22867 SN - 2046-2069 ER - TY - JOUR TI - Nanoconfinement-Induced Structures in Chiral Liquid Crystals AU - Melle, Michael AU - Theile, Madlona AU - Hall, Carol K. AU - Schoen, Martin T2 - INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES AB - We employ Monte Carlo simulations in a specialized isothermal-isobaric and in the grand canonical ensemble to study structure formation in chiral liquid crystals as a function of molecular chirality. Our model potential consists of a simple Lennard-Jones potential, where the attractive contribution has been modified to represent the orientation dependence of the interaction between a pair of chiral liquid-crystal molecules. The liquid crystal is confined between a pair of planar and atomically smooth substrates onto which molecules are anchored in a hybrid fashion. Hybrid anchoring allows for the formation of helical structures in the direction perpendicular to the substrate plane without exposing the helix to spurious strains. At low chirality, we observe a cholesteric phase, which is transformed into a blue phase at higher chirality. More specifically, by studying the unit cell and the spatial arrangement of disclination lines, this blue phase can be established as blue phase II. If the distance between the confining substrates and molecular chirality are chosen properly, we see a third structure, which may be thought of as a hybrid, exhibiting mixed features of a cholesteric and a blue phase. DA - 2013/9// PY - 2013/9// DO - 10.3390/ijms140917584 VL - 14 IS - 9 SP - 17584-17607 SN - 1422-0067 KW - liquid crystal KW - chirality KW - cholesteric and blue phases KW - confinement KW - Monte Carlo simulation ER - TY - JOUR TI - Large effect of titanium precursor on surface reactivity and mechanical strength of electrospun nanofibers coated with TiO2 by atomic layer deposition AU - McClure, Christina D. AU - Oldham, Christopher J. AU - Walls, Howard J. AU - Parsons, Gregory N. T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Encapsulating and functionalizing polymer nanofibers can improve the polymers chemical resistance and surface reactivity, enabling new applications including biosensing, flexible electronics, gas filtration, and chemical separations. Polymer fiber functionalization typically involves energy intensive wet chemical treatments and/or plasma exposure. Recent results show low temperature atomic layer deposition (ALD) to be a viable means to coat nanofibers with uniform and conformal inorganic and hybrid organic–inorganic layers. For this article, the authors describe how the mechanical properties of nylon-6 nanofibers are affected by ALD coatings of TiO2 and other metal oxides. They find that the stress–strain behavior of nylon-6 nanofibers depends strongly on the specific precursor chemistry used in the coating process. For ALD TiO2 coatings, titanium tetrachloride tended to embrittle the fibers, whereas titanium isopropoxide had a more subtle effect. Physical characterization shows that the TiCl4 diffused into the nylon-6 and reacted subsurface, whereas the titanium isopropoxide tended to react on the surface producing a more abrupt organic/inorganic interface. Results show that precursor choice is an important factor when designing thin film coating processes on polymeric substrates. DA - 2013/// PY - 2013/// DO - 10.1116/1.4817718 VL - 31 IS - 6 SP - SN - 0734-2101 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000327253900031&KeyUID=WOS:000327253900031 ER - TY - JOUR TI - Fabrication and Characterization of SiO2/PVDF Composite Nanofiber-Coated PP Nonwoven Separators for Lithium-Ion Batteries AU - Yanilmaz, Meltem AU - Chen, Chen AU - Zhang, Xiangwu T2 - JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS AB - ABSTRACT SiO 2 /polyvinylidene fluoride (PVDF) composite nanofiber‐coated polypropylene (PP) nonwoven membranes were prepared by electrospinning of SiO 2 /PVDF dispersions onto both sides of PP nonwovens. The goal of this study was to combine the good mechanical strength of PP nonwoven with the excellent electrochemical properties of SiO 2 /PVDF composite nanofibers to obtain a new high‐performance separator. It was found that the addition of SiO 2 nanoparticles played an important role in improving the overall performance of these nanofiber‐coated nonwoven membranes. Among the membranes with various SiO 2 contents, 15% SiO 2 /PVDF composite nanofiber‐coated PP nonwoven membranes provided the highest ionic conductivity of 2.6 × 10 −3 S cm −1 after being immersed in a liquid electrolyte, 1 mol L −1 lithium hexafluorophosphate in ethylene carbonate, dimethyl carbonate and diethyl carbonate. Compared with pure PVDF nanofiber‐coated PP nonwoven membranes, SiO 2 /PVDF composite fiber‐coated PP nonwoven membranes had greater liquid electrolyte uptake, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. SiO 2 /PVDF composite fiber‐coated PP nonwoven membrane separators were assembled into lithium/lithium iron phosphate cells and demonstrated high cell capacities and good cycling performance at room temperature. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51 , 1719–1726 DA - 2013/12/1/ PY - 2013/12/1/ DO - 10.1002/polb.23387 VL - 51 IS - 23 SP - 1719-1726 SN - 1099-0488 UR - https://publons.com/publon/7178359/ KW - battery separators KW - electrospinning KW - fibers KW - nanocomposites KW - nanoparticles KW - polyvinylidene fluoride KW - SiO2 nanoparticles ER - TY - JOUR TI - Evaluation of O/W microemulsions to penetrate the capillary structure of woody biomass: interplay between composition and formulation in green processing AU - Carrillo, Carlos A. AU - Saloni, Daniel AU - Rojas, Orlando J. T2 - GREEN CHEMISTRY AB - The ability of microemulsions to overcome the complex capillary structure of wood is revealed in relation to its composition and formulation. The oil phase (limonene in this study) of O/W microemulsions is found to be critical for effective flooding. The type of amphiphile molecule used, including sodium lignosulfonate and alkyl polyglucosides as well as reference sodium dodecylsulfate and silicone-based surfactants, together with the viscosity of the resulting microemulsions were the main factors determining the dynamics and extent of fluid penetration. The associated observations were ascribed to the balance of the affinities of the surfactants for the substrate and its conductive elements. Owing to the inherent morphological and chemical features, large differences were observed as far as impregnation susceptibility of different wood types is concerned. By using appropriate surfactant mixtures it was possible for the microemulsions to penetrate the most recalcitrant woody biomass studied, with efficiencies up to 83% higher than that of water, at atmospheric pressure and room temperature. Application of microemulsions is a new alternative for green and efficient pre-treatment of woody biomass in biorefineries, to deliver (bio)chemical functions to the constrained spaces of the cell wall and to increase its accessibility. DA - 2013/// PY - 2013/// DO - 10.1039/c3gc41325j VL - 15 IS - 12 SP - 3377-3386 SN - 1463-9270 ER - TY - JOUR TI - Epitaxial lead zirconate titanate on gallium nitride (vol 113, 074107, 2013) AU - Paisley, E. A. AU - Craft, H. S. AU - Losego, M. D. AU - Lu, H. AU - Gruverman, A. AU - Collazo, R. AU - Sitar, Z. AU - Maria, J. P. T2 - Journal of Applied Physics DA - 2013/// PY - 2013/// VL - 114 IS - 23 ER - TY - JOUR TI - Electrolyte solvation and ionic association IV. Acetonitrile-lithium difluoro(oxalato)borate (LiDFOB) mixtures AU - Han, S. D. AU - Borodin, O. AU - Allen, J. L. AU - Seo, D. M. AU - McOwen, D. W. AU - Yun, S. H. AU - Henderson, W. A. T2 - Journal of the Electrochemical Society DA - 2013/// PY - 2013/// VL - 160 IS - 11 SP - A2100-2110 ER - TY - JOUR TI - Effect of CVD carbon coatings on Si@CNF composite as anode for lithium-ion batteries AU - Fu, K. AU - Xue, L. G. AU - Yildiz, O. AU - Li, S. L. AU - Lee, H. AU - Li, Y. AU - Xu, G. J. AU - Zhou, L. AU - Bradford, P. D. AU - Zhang, Xiangwu AU - al. T2 - NANO ENERGY AB - Lithium-ion battery (LIB) anodes with high capacity and binder free structure were synthesized from carbon nanofibers that contained silicon nanoparticles (Si@CNF). The particle filled nonwoven structures were produced by an electrospinning and subsequent carbonization process. Pristine Si@CNF composites had Si nanoparticles exposed on the fiber surface. As produced, the Si nanoparticles could become detached from the nanofiber surface during cycling, causing severe structural damage and capacity loss. In order to prevent Si from detaching from the nanofiber surface, the Si@CNF composite was then treated with a thermal chemical vapor deposition (CVD) technique to make Si completely coated with a carbon matrix. The carbon coated Si@CNF (Si@CNF-C) composites were synthesized with different Si contents (10, 30, and 50 wt%) for different CVD treatment times (30, 60, and 90 min). It was found that the initial coulombic efficiency of Si@CNF-C could be increased via the amorphous carbon by stabilizing solid-electrolyte-interface (SEI) formation on surface. The capacity and cyclic stability were improved by the CVD carbon coating, especially for the 30 wt% Si@CNF-C composite with 90 min CVD coating, a CVD amorphous carbon coating of less than 1% by weight on Si@CNF composites contributed to more than 200% improvement in cycling performance. Results indicate that the CVD carbon coating is an effective approach to improve the electrochemical properties of Si@CNF composites making this a potential route to obtain high-energy density anode materials for LIBs. DA - 2013/9// PY - 2013/9// DO - 10.1016/j.nanoen.2013.03.019 VL - 2 IS - 5 SP - 976-986 SN - 2211-3282 UR - https://publons.com/publon/7178363/ KW - Lithium-ion battery anode KW - Silicon KW - Carbon nanofibers KW - CVD KW - SEI KW - Coulombic efficiency ER - TY - JOUR TI - Bidirectional coupling between integrin-mediated signaling and actomyosin mechanics explains matrix-dependent intermittency of leading-edge motility AU - Welf, Erik S. AU - Johnson, Heath E. AU - Haugh, Jason M. T2 - MOLECULAR BIOLOGY OF THE CELL AB - Animal cell migration is a complex process characterized by the coupling of adhesion, cytoskeletal, and signaling dynamics. Here we model local protrusion of the cell edge as a function of the load-bearing properties of integrin-based adhesions, actin polymerization fostered by adhesion-mediated signaling, and mechanosensitive activation of RhoA that promotes myosin II-generated stress on the lamellipodial F-actin network. Analysis of stochastic model simulations illustrates how these pleiotropic functions of nascent adhesions may be integrated to govern temporal persistence and frequency of protrusions. The simulations give mechanistic insight into the documented effects of extracellular matrix density and myosin abundance, and they show characteristic, nonnormal distributions of protrusion duration times that are similar to those extracted from live-cell imaging experiments. Analysis of the model further predicts relationships between measurable quantities that reflect the partitioning of stress between tension on F-actin-bound adhesions, which act as a molecular clutch, and dissipation by retrograde F-actin flow. DA - 2013/12/15/ PY - 2013/12/15/ DO - 10.1091/mbc.e13-06-0311 VL - 24 IS - 24 SP - 3945-3955 SN - 1939-4586 ER - TY - JOUR TI - Water-Wettable Polypropylene Fibers by Facile Surface Treatment Based on Soy Proteins AU - Salas, Carlos AU - Genzer, Jan AU - Lucia, Lucian A. AU - Hubbe, Martin A. AU - Rojas, Orlando J. T2 - ACS APPLIED MATERIALS & INTERFACES AB - Modification of the wetting behavior of hydrophobic surfaces is essential in a variety of materials, including textiles and membranes that require control of fluid interactions, adhesion, transport processes, sensing, etc. This investigation examines the enhancement of wettability of an important class of textile materials, viz., polypropylene (PP) fibers, by surface adsorption of different proteins from soybeans, including soy flour, isolate,glycinin, and β-conglycinin. Detailed investigations of soy adsorption from aqueous solution (pH 7.4, 25 °C) on polypropylene thin films is carried out using quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). A significant amount of protein adsorbs onto the PP surfaces primarily due to hydrophobic interactions. We establish that adsorption of a cationic surfactant, dioctadecyldimethylammonium bromide (DODA) onto PP surfaces prior to the protein deposition dramatically enhances its adsorption. The adsorption of proteins from native (PBS buffer, pH 7.4, 25 °C) and denatured conditions (PBS buffer, pH 7.4, 95 °C) onto DODA-treated PP leads to a high coverage of the proteins on the PP surface as confirmed by a significant improvement in water wettability. A shift in the contact angle from 128° to completely wettable surfaces (≈0°) is observed and confirmed by imaging experiments conducted with fluorescence tags. Furthermore, the results from wicking tests indicate that hydrophobic PP nonwovens absorb a significant amount of water after protein treatment, i.e., the PP-modified surfaces become completely hydrophilic. DA - 2013/7/24/ PY - 2013/7/24/ DO - 10.1021/am401065t VL - 5 IS - 14 SP - 6541-6548 SN - 1944-8252 KW - soy proteins KW - surface modification KW - polypropylene nonwovens KW - protein adsorption KW - wettability KW - wicking ER - TY - JOUR TI - Synthesis and characterization of xLi(2)MnO(3) center dot (1-x)LiMn1/3Ni1/3Co1/3O2 composite cathode materials for rechargeable lithium-ion batteries AU - Toprakci, Ozan AU - Toprakci, Hatice A. K. AU - Li, Ying AU - Ji, Liwen AU - Xue, Leigang AU - Lee, Hun AU - Zhang, Shu AU - Zhang, Xiangwu T2 - JOURNAL OF POWER SOURCES AB - Various xLi2MnO3·(1 − x)LiCo1/3Ni1/3Mn1/3O2 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) cathode materials were prepared by the one-step sol–gel route. The structure of xLi2MnO3·(1 − x)LiCo1/3Ni1/3Mn1/3O2 composites was determined by X-ray diffraction analysis. The surface morphology and microstructure of xLi2MnO3·(1 − x)LiCo1/3Ni1/3Mn1/3O2 composites were characterized using scanning electron microscopy and transmission electron microscopy. Electrochemical performance of xLi2MnO3·(1 − x)LiCo1/3Ni1/3Mn1/3O2 composites was evaluated in terms of capacity, cycling performance and rate capability. Although the morphology and structure were found to be affected by the Li2MnO3 content, all composites showed an α-NaFeO2 structure with R3m space group. Electrochemical results showed that cells using 0.3Li2MnO3·0.7LiCo1/3Ni1/3Mn1/3O2 composites had good performance, in terms of large reversible capacity, prolonged cycling stability, and excellent rate capability. DA - 2013/11/1/ PY - 2013/11/1/ DO - 10.1016/j.jpowsour.2013.04.155 VL - 241 SP - 522-528 SN - 0378-7753 UR - https://publons.com/publon/674386/ KW - Lithium-ion batteries KW - Cathodes KW - Electrochemical performance KW - Li-rich KW - xLi(2)MnO(3)center dot(1-x)LiCo1/3Ni1/3Mn1/3O2 ER - TY - JOUR TI - Stabilizing Small Molecules on Metal Oxide Surfaces Using Atomic Layer Deposition AU - Hanson, Kenneth AU - Losego, Mark D. AU - Kalanyan, Berc AU - Parsons, Gregory N. AU - Meyer, Thomas J. T2 - NANO LETTERS AB - Device lifetimes and commercial viability of dye-sensitized solar cells (DSSCs) and dye-sensitized photoelectrosynthesis cells (DSPECs) are dependent on the stability of the surface bound molecular chromophores and catalysts. Maintaining the integrity of the solution-metal oxide interface is especially challenging in DSPECs for water oxidation where it is necessary to perform high numbers of turnovers, under irradiation in an aqueous environment. In this study, we describe the atomic layer deposition (ALD) of TiO2 on nanocrystalline TiO2 prefunctionalized with the dye molecule [Ru(bpy)2(4,4'-(PO3H2)bpy)](2+) (RuP) as a strategy to stabilize surface bound molecules. The resulting films are over an order of magnitude more photostable than untreated films and the desorption rate constant exponentially decreases with increased thickness of ALD TiO2 overlayers. However, the injection yield for TiO2-RuP with ALD TiO2 also decreases with increasing overlayer thickness. The combination of decreased injection yield and 95% quenched emission suggests that the ALD TiO2 overlayer acts as a competitive electron acceptor from RuP*, effectively nonproductively quenching the excited state. The ALD TiO2 also increases back electron transfer rates, relative to the untreated film, but is independent of overlayer thickness. The results for TiO2-RuP with an ALD TiO2 overlayer are compared with similar films having ALD Al2O3 overlayers. DA - 2013/10// PY - 2013/10// DO - 10.1021/nl402416s VL - 13 IS - 10 SP - 4802-4809 SN - 1530-6992 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000326356300035&KeyUID=WOS:000326356300035 KW - Dye-sensitized KW - stability KW - atomic layer deposition KW - photoelectrochemical cell KW - water splitting KW - electron transfer ER - TY - JOUR TI - Spectroscopic Detection of Medium Range Order in Device Grade Hydrogenated Amorphous Silicon AU - Lucovsky, Gerry AU - Parsons, Greg AU - Zeller, Daniel AU - Kim, Jinwoo T2 - JAPANESE JOURNAL OF APPLIED PHYSICS AB - This article addresses low defect densities in hydrogenated amorphous silicon, a-Si 1- x :H x with approximately 10 at. % bonded H, x ∼0.1. Based low defect densities at mid-gap, ∼0.5 to 1×10 16 cm -3 , a-Si:H thin films have been integrated into photovoltaic (PV) devices and thin film transistors (TFT's). Amorphous Si (a-Si) thin films with no detectable bonded-H have been used as precursors for polycrystalline gate electrodes in microelectronic applications. PV and TFT alloys have been deposited by glow discharge (GD), remote plasma-enhanced chemical vapor deposition (RPECVD), and reactive magnetron sputtering (RMS) with different bonded-H content determined by deposition precursors and substrate temperatures. Two conditions are required for the lowest Si dangling bond densities: (i) a monohydride, Si–H, concentration of ∼10 at. % H, and (ii) deposition, and/or a post-deposition annealing at 240 to 300 °C. DA - 2013/4// PY - 2013/4// DO - 10.7567/jjap.52.04cr10 VL - 52 IS - 4 SP - SN - 1347-4065 ER - TY - JOUR TI - Size-dependent regulation of dorsal–ventral patterning in the early Drosophila embryo AU - Garcia, Mayra AU - Nahmad, Marcos AU - Reeves, Gregory T. AU - Stathopoulos, Angelike T2 - Developmental Biology AB - How natural variation in embryo size affects patterning of the Drosophila embryo dorsal-ventral (DV) axis is not known. Here we examined quantitatively the relationship between nuclear distribution of the Dorsal transcription factor, boundary positions for several target genes, and DV axis length. Data were obtained from embryos of a wild-type background as well as from mutant lines inbred to size select embryos of smaller or larger sizes. Our data show that the width of the nuclear Dorsal gradient correlates with DV axis length. In turn, for some genes expressed along the DV axis, the boundary positions correlate closely with nuclear Dorsal levels and with DV axis length; while the expression pattern of others is relatively constant and independent of the width of the Dorsal gradient. In particular, the patterns of snail (sna) and ventral nervous system defective (vnd) correlate with nuclear Dorsal levels and exhibit scaling to DV length; while the pattern of intermediate neuroblasts defective (ind) remains relatively constant with respect to changes in Dorsal and DV length. However, in mutants that exhibit an abnormal expansion of the Dorsal gradient which fails to scale to DV length, only sna follows the Dorsal distribution and exhibits overexpansion; in contrast, vnd and ind do not overexpand suggesting some additional mechanism acts to refine the dorsal boundaries of these two genes. Thus, our results argue against the idea that the Dorsal gradient works as a global system of relative coordinates along the DV axis and suggest that individual targets respond to changes in embryo size in a gene-specific manner. DA - 2013/9// PY - 2013/9// DO - 10.1016/J.YDBIO.2013.06.020 VL - 381 IS - 1 SP - 286-299 J2 - Developmental Biology LA - en OP - SN - 0012-1606 UR - http://dx.doi.org/10.1016/J.YDBIO.2013.06.020 DB - Crossref KW - Developmental patterning KW - Dorsal gradient KW - Gene expression KW - Morphogen KW - Scaling KW - Drosophila melanogaster ER - TY - JOUR TI - Shock tube measurements and model development for morpholine pyrolysis and oxidation at high pressures AU - Li, Sijie AU - Davidson, David F. AU - Hanson, Ronald K. AU - Labbe, Nicole J. AU - Westmoreland, Phillip R. AU - Oßwald, Patrick AU - Kohse-Höinghaus, Katharina T2 - Combustion and Flame AB - Fuel decomposition time-history measurements during morpholine pyrolysis and ignition delay time measurements during morpholine oxidation were carried out behind reflected shock waves in a high-pressure shock tube. For the pyrolysis studies, morpholine concentrations of 5000 ppm in argon were employed, with experiments covering the temperature range 1086–1404 K and pressure range 20–23.6 atm. For the ignition delay time measurements, experiments covered the temperature range 866–1197 K with pressures near 15 and 25 atm, oxygen mole fractions of 4% and 21%, and equivalence ratios of 0.5, 1, and 2. A morpholine reaction set developed to simulate low-pressure flames was updated based on the current shock tube data, recently published rate constants for relevant reactions, and newly calculated thermochemistry. The simulations from the updated set were in good agreement with the current shock tube experiments. DA - 2013/9// PY - 2013/9// DO - 10.1016/j.combustflame.2013.03.027 VL - 160 IS - 9 SP - 1559-1571 J2 - Combustion and Flame LA - en OP - SN - 0010-2180 UR - http://dx.doi.org/10.1016/j.combustflame.2013.03.027 DB - Crossref KW - Morpholine KW - Pyrolysis KW - Oxidation KW - Model development KW - Shock tube KW - Laser absorption ER - TY - JOUR TI - Protein selection using yeast surface display AU - Gera, Nimish AU - Hussain, Mahmud AU - Rao, Balaji M. T2 - METHODS AB - Binding proteins are typically isolated from combinatorial libraries of scaffold proteins using one of the many library screening tools available, such as phage display, yeast surface display or mRNA display. A key principle underlying these screening technologies is the establishment of a link between each unique mutant protein and its corresponding genetic code. The mutant proteins binding a desired target species are separated and subsequently identified using the genetic code. In this review, we largely focus on the use of yeast surface display for the isolation of binding proteins from combinatorial libraries. In yeast surface display, the yeast cell links the mutant protein to its coding DNA. Each yeast cell expresses the mutant proteins as fusions to a yeast cell wall protein; the yeast cell also carries plasmid DNA that codes for the mutant protein. Over the years, the yeast surface display platform has emerged as a powerful tool for protein engineering, and has been used in a variety of applications including affinity maturation, epitope mapping and biophysical characterization of proteins. Here we present a broad overview of the yeast surface display system and its applications, and compare it with other contemporary screening platforms. Further, we present detailed protocols for the use of yeast surface display to isolate de novo binding proteins from combinatorial libraries, and subsequent biophysical characterization of binders. These protocols can also be easily modified for affinity maturation of the isolated de novo binders. DA - 2013/3/15/ PY - 2013/3/15/ DO - 10.1016/j.ymeth.2012.03.014 VL - 60 IS - 1 SP - 15-26 SN - 1046-2023 KW - Yeast surface display KW - Protein engineering KW - Library screening KW - Biophysical characterization KW - Alternative scaffolds ER - TY - JOUR TI - Plasma, tumor and tissue pharmacokinetics of Docetaxel delivered via nanoparticles of different sizes and shapes in mice bearing SKOV-3 human ovarian carcinoma xenograft AU - Chu, Kevin S. AU - Hasan, Warefta AU - Rawal, Sumit AU - Walsh, Mark D. AU - Enlow, Elizabeth M. AU - Luft, J. Christopher AU - Bridges, Arlene S. AU - Kuijer, Jennifer L. AU - Napier, Mary E. AU - Zamboni, William C. AU - DeSimone, Joseph M. T2 - Nanomedicine: Nanotechnology, Biology and Medicine AB - The particle fabrication technique PRINT® was used to fabricate monodisperse size and shape specific poly(lactide-co-glycolide) particles loaded with the chemotherapeutic Docetaxel. The pharmacokinetics of two cylindrical shaped particles with diameter=80nm; height=320nm (PRINT-Doc-80×320) and d=200nm; h=200nm (PRINT-Doc-200×200) were compared to Docetaxel in mice bearing human ovarian carcinoma SKOV-3 flank xenografts. The Docetaxel plasma exposure was ~20-fold higher for both particles compared to docetaxel. Additionally, the volume of distribution (Vd) of Docetaxel in PRINT formulations was ~18-fold (PRINT-Doc-80×320) and ~33-fold (PRINT-Doc-200×200) lower than Docetaxel. The prolonged duration of Docetaxel in plasma when dosed with PRINT formulations subsequently led to increased tumor exposure of Docetaxel from 0 to 168h (~53% higher for PRINT-Doc-80×320 and ~76% higher for PRINT-Doc-200×200 particles). PRINT-Doc-80×320 had lower exposures in the liver, spleen and lung compared with PRINT-Doc-200×200. Thus, the use of particles with smaller feature size may be preferred to decrease clearance by organs of the mononuclear phagocyte system.In this study, the plasma, tumor, and tissue pharmacokinetics of different Docetaxel nanoparticles of precise shape and size were characterized in mice with human ovarian carcinoma xenograft. It is concluded that the use of particles with smaller feature size may be preferred to decrease clearance by organs of the mononuclear phagocyte system. DA - 2013/7// PY - 2013/7// DO - 10.1016/j.nano.2012.11.008 VL - 9 IS - 5 SP - 686-693 J2 - Nanomedicine: Nanotechnology, Biology and Medicine LA - en OP - SN - 1549-9634 UR - http://dx.doi.org/10.1016/j.nano.2012.11.008 DB - Crossref KW - Soft-lithography KW - PLGA KW - Nanoparticle KW - Shape KW - Pharmacokinetics ER - TY - JOUR TI - Low-Temperature Atomic Layer Deposition of Tungsten using Tungsten Hexafluoride and Highly-diluted Silane in Argon AU - Kalanyan, Berc AU - Losego, Mark D. AU - Oldham, Christopher J. AU - Parsons, Gregory N. T2 - CHEMICAL VAPOR DEPOSITION AB - Abstract Inherent chemical hazards in atomic layer deposition (ALD) processes can be mitigated significantly by careful selection of precursor materials. This work describes the effect of silane (SiH 4 ) exposure on tungsten ALD growth when the silane is heavily diluted (2 at.‐%) in argon. A wide ALD temperature window from 200 to ∼300°C is identified, exhibiting a growth rate of between 5 and 6 Å per ALD cycle using SiH 4 and tungsten hexafluoride (WF 6 ) exposures of ∼6 × 10 5 and ∼5 × 10 5 Langmuirs (L), respectively. For deposition at lower temperature (150°C), growth rates of ∼4.5 Å per cycle are obtained using a silane exposure of 30 s per cycle, where the partial pressure of silane at the inlet is controlled at 40 mTorr (corresponding to 1.2 × 10 6 L of silane). Compositional analysis by secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES) show less than ∼5 at.‐% Si in the W films, with the smallest Si content in films deposited at 300°C. We also describe effects of hot‐wall reactor preconditioning on film growth. We conclude that the dilute silane co‐reactant offers an alternative to the common disilane, borosilane, or undiluted silane precursors, allowing well‐controlled W deposition at 150°C. DA - 2013/6// PY - 2013/6// DO - 10.1002/cvde.201307053 VL - 19 IS - 4-6 SP - 161-166 SN - 0948-1907 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000320470300013&KeyUID=WOS:000320470300013 KW - Aluminum oxide KW - Atomic layer deposition KW - Process safety KW - Silane KW - Tungsten ER - TY - JOUR TI - Ionic liquids behave as dilute electrolyte solutions AU - Gebbie, M. A. AU - Valtiner, M. AU - Banquy, X. AU - Fox, E. T. AU - Henderson, W. A. AU - Israelachvili, J. N. T2 - Proceedings of the National Academy of Sciences of the United States of America DA - 2013/// PY - 2013/// VL - 110 IS - 24 SP - 9674-9679 ER - TY - JOUR TI - Improvement of cyclability of silicon-containing carbon nanofiber anodes for lithium-ion batteries by employing succinic anhydride as an electrolyte additive AU - Li, Ying AU - Xu, Guanjie AU - Yao, Yingfang AU - Xue, Leigang AU - Zhang, Shu AU - Lu, Yao AU - Toprakci, Ozan AU - Zhang, Xiangwu T2 - JOURNAL OF SOLID STATE ELECTROCHEMISTRY DA - 2013/5// PY - 2013/5// DO - 10.1007/s10008-013-2005-7 VL - 17 IS - 5 SP - 1393-1399 SN - 1433-0768 UR - https://publons.com/publon/674383/ KW - Electrospinning KW - Carbon nanofiber KW - Si nanoparticle KW - Succinic anhydride KW - Lithium-ion batteries ER - TY - JOUR TI - Highly Conductive and Flexible Nylon-6 Nonwoven Fiber Mats Formed using Tungsten Atomic Layer Deposition AU - Kalanyan, Berç AU - Oldham, Christopher J. AU - Sweet, William J., III AU - Parsons, Gregory N. T2 - ACS Applied Materials & Interfaces AB - Low-temperature vapor-phase tungsten atomic layer deposition (ALD) using WF6 and dilute silane (SiH4, 2% in Ar) can yield highly conductive coatings on nylon-6 microfiber mats, producing flexible and supple nonwovens with conductivity of ∼1000 S/cm. We find that an alumina nucleation layer, reactant exposure, and deposition temperature all influence the rate of W mass uptake on 3D fibers, and film growth rate is calibrated using high surface area anodic aluminum oxide. Transmission electron microscopy (TEM) reveals highly conformal tungsten coatings on nylon fibers with complex “winged” cross-section. Using reactant gas “hold” sequences during the ALD process, we conclude that reactant species can transport readily to reactive sites throughout the fiber mat, consistent with conformal uniform coverage observed by TEM. The conductivity of 1000 S/cm for the W-coated nylon is much larger than found in other conductive nonwovens. We also find that the nylon mats maintain 90% of their conductivity after being flexed around cylinders with radii as small as 0.3 cm. Metal ALD coatings on nonwovens make possible the solvent-free functionalization of textiles for electronic applications. DA - 2013/5/31/ PY - 2013/5/31/ DO - 10.1021/AM401095R VL - 5 IS - 11 SP - 5253-5259 J2 - ACS Appl. Mater. Interfaces LA - en OP - SN - 1944-8244 1944-8252 UR - http://dx.doi.org/10.1021/AM401095R DB - Crossref KW - tungsten KW - atomic layer deposition KW - conductive fibers KW - flexible electronics KW - nonwovens ER - TY - JOUR TI - High-performance Sn/Carbon Composite Anodes Derived from Sn(II) Acetate/Polyacrylonitrile Precursors by Electrospinning Technology AU - Li, Shuli AU - Xue, Leigang AU - Fu, Kun AU - Xia, Xin AU - Zhao, Chengxin AU - Zhang, Xiangwu T2 - CURRENT ORGANIC CHEMISTRY AB - Sn/carbon composite nanofibers with various compositions were prepared from Sn(II) acetate/polyacrylonitrile (PAN) precursors by a combination of electrospinning and carbonization methods, and their potential use as anode materials for rechargeable lithiumion batteries was investigated. The composite electrode derived from 20 wt% Sn(II) acetate/PAN precursor showed excellent electrochemical properties, including a large reversible capacity of 699 mAh g‾1 and a high capacity retention of 83% in 50 cycles. Sn/carbon composite nanofibers exhibited enhanced electrochemical performance ascribing to the combination of the properties of both Sn nanoparticles (large Li storage capability) and carbon matrices (long cycle life), and therefore could be potentially used in high-energy rechargeable lithium-ion batteries. Keywords: Tin, tin(II) acetate, Composite nanofiber, Electrospinning, Lithium-ion battery. DA - 2013/7// PY - 2013/7// DO - 10.2174/1385272811317130011 VL - 17 IS - 13 SP - 1448-1454 SN - 1385-2728 UR - https://publons.com/publon/7178342/ KW - Tin KW - tin(II) acetate KW - Composite nanofiber KW - Electrospinning KW - Lithium-ion battery ER - TY - JOUR TI - High pressure effect in nanoporous carbon materials: Effects of pore geometry AU - Long, Yun AU - Śliwińska-Bartkowiak, Małgorzata AU - Drozdowski, Henryk AU - Kempiński, Mateusz AU - Phillips, Katherine A. AU - Palmer, Jeremy C. AU - Gubbins, Keith E. T2 - Colloids and Surfaces A: Physicochemical and Engineering Aspects AB - Abundant experimental evidence suggests that adsorbates confined in nanoporous materials exhibit high pressures, such as high pressure crystal structures, high pressure chemical reactions, and the deformation of pore walls due to the adsorbate. We report molecular simulation studies of the pressure tensor for simple adsorbates (e.g. argon) in carbon nanopores of slit, cylindrical and spherical geometries. We find that for modest bulk phase pressures of 1 bar or less, the pressures parallel to the pore walls (tangential pressure) is of the order 104–105 bar, while the pressure normal to the wall is of the order of 103 bar, and can be positive or negative depending on the pore size. Moreover, we find that the pore geometry has a large effect on the structure of the adsorbate and thus on the in-pore pressure because of the curvature that determines the strength of the adsorbate–wall interaction. For the same pore size, temperature and bulk pressure, the in-pore tangential pressure is the largest in spherical pores, followed by that in cylindrical pores and slit pores. We also study the normal pressure of carbon tetrachloride and water confined in activated carbon fibers by molecular simulations and experiments. The pressure acting on the pore wall is found to be of the order of several thousand bar by both methods. Experiments also find that the pore can be expanded or contracted, depending on pore width, as we predict by molecular simulation. DA - 2013/11// PY - 2013/11// DO - 10.1016/j.colsurfa.2012.11.024 VL - 437 SP - 33-41 J2 - Colloids and Surfaces A: Physicochemical and Engineering Aspects LA - en OP - SN - 0927-7757 UR - http://dx.doi.org/10.1016/j.colsurfa.2012.11.024 DB - Crossref ER - TY - JOUR TI - Generation and Properties of Antibacterial Coatings Based on Electrostatic Attachment of Silver Nanoparticles to Protein-Coated Polypropylene Fibers AU - Goli, Kiran K. AU - Gera, Nimish AU - Liu, Xiaomeng AU - Rao, Balaji M. AU - Rojas, Orlando J. AU - Genzer, Jan T2 - ACS APPLIED MATERIALS & INTERFACES AB - We present a simple method for attaching silver nanoparticles to polypropylene (PP) fibers in a two-step process to impart antibacterial properties. Specifically, PP fibers are pretreated by the adsorption from an aqueous solution of heat-denatured lysozyme (LYS) followed by LYS cross-linking using glutaraldehyde and sodium borohydride. At neutral pH, the surface of the adsorbed LYS layer is enriched with numerous positive charges. Silver nanoparticles (AgNPs) capped with trisodium citrate are subsequently deposited onto the protein-coated PP. Nanoparticle binding is mediated by electrostatic interactions between the positively charged LYS layer and the negatively charged AgNPs. The density of AgNPs deposited on PP depends on the amount of protein adsorbed on the surface. UV-vis spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy are employed to follow all preparation steps and to characterize the resulting functional surfaces. The antibacterial activity of the modified surfaces is tested against gram negative bacteria Escherichia coli (E. coli). Overall, our results show that PP surfaces coated with AgNPs exhibit excellent antibacterial activity with 100% removal efficiency. DA - 2013/6/12/ PY - 2013/6/12/ DO - 10.1021/am4011644 VL - 5 IS - 11 SP - 5298-5306 SN - 1944-8252 KW - antibacterial KW - polypropylene KW - protein adsorption KW - nanoparticle KW - functional coating ER - TY - JOUR TI - Embedded collagen deformation models for computational modeling of healthy, keratoconic, and crosslinked corneas AU - Foster, C. D. AU - Gongal, D. AU - Begaj, T. AU - Luo, M. T2 - Journal of Mechanics in Medicine and Biology DA - 2013/// PY - 2013/// VL - 13 IS - 3 ER - TY - JOUR TI - Effect of Protein-like Copolymers Composition on the Phase Separation Dynamics of a Polymer Blend: A Monte Carlo Simulation AU - Malik, Ravish AU - Hall, Carol K. AU - Genzer, Jan T2 - MACROMOLECULES AB - We use kinetic Monte Carlo simulation based on the bond fluctuation model to investigate the dynamics of phase separation in immiscible 80/20 A/B binary polymer blends, comprising 80% and 20% of A and B components, respectively, in the presence of ≈4.92% 30-mer protein-like copolymer (PLC) made of C and D segments. The molecular interactions are chosen such that there is an attraction between A and C and between B and D segments and no interaction between like segments; all other interaction energies have been chosen to be repulsive. The PLC migration to and presence at the A/B interface effectively slow down the process of phase separation in binary blends, thereby minimizing the unfavorable A/B contacts and reducing the A/B interfacial tension. The ability of PLCs to effectively retard the process of phase separation depends sensitively on the PLC composition. PLCs with 0.3 ≤ xC ≤ 0.5, where xC is the mole fraction of C, are most effective in compatibilizing the 80/20 A/B binary blend. The growth of phase-separated domains follows a dynamical scaling law for both the binary and ternary blends compatibilized by PLCs in the late stage of phase separation with universal scaling functions that are nearly independent of PLC composition. DA - 2013/5/28/ PY - 2013/5/28/ DO - 10.1021/ma400187u VL - 46 IS - 10 SP - 4207-4214 SN - 1520-5835 ER - TY - JOUR TI - Cilia-Mimetic Hairy Surfaces Based on End-Immobilized Nanocellulose Colloidal Rods AU - Lokanathan, Arcot R. AU - Nykanen, Antti AU - Seitsonen, Jani AU - Johansson, Leena-Sisko AU - Campbell, Joseph AU - Rojas, Orlando J. AU - Ikkala, Olli AU - Laine, Janne T2 - BIOMACROMOLECULES AB - We show a simple method toward nanoscale cilia-like structures, i.e., functional hairy surfaces, upon topochemically functionalizing nanorods of cellulose nanocrystals (CNCs) with thiol end groups (CNC-SHs), which leads to their immobilization onto a gold surface from one end, still allowing their orientational mobility. CNCs having a lateral dimension of 3-5 nm and length of 50-500 nm incorporate the native crystalline structure with hydrogen-bonded cellulose chains in the parallel configuration. This facilitates asymmetric, selective chemical modification of the reducing ends through reductive amination. Successful thiol functionalization is demonstrated using cryo transmission electron microscopy based on selective attachment of silver nanoparticles to the CNC-SH ends to form Janus-like colloidal rod-sphere adducts. The extent of thiol modification of CNC-SHs is quantified using X-ray photoelectron spectroscopy. The promoted binding of CNC-SHs on gold surfaces is shown by atomic force microscopy and quartz crystal microbalance, where the high dissipation suggests pronounced orientational mobility due to flexible joints at one rod end onto the surfaces. That the joints are flexible is also shown by the bending and realignment of the CNC-SH rods using a receding triple-phase evaporation front of a drying drop of water. The ability of the hairy surface to size-selectively resist particle binding was also investigated. As the CNCs are piezoelectric and allow magnetic functionalization by nanoparticles, we foresee a general platform for nanosized artificial cilia for fluid manipulation and controlled adsorption/desorption. DA - 2013/8// PY - 2013/8// DO - 10.1021/bm400633r VL - 14 IS - 8 SP - 2807-2813 SN - 1526-4602 ER - TY - JOUR TI - Atomic Layer Deposition of High Performance Ultrathin TiO2 Blocking Layers for Dye-Sensitized Solar Cells AU - Kim, Do Han AU - Woodroof, Mariah AU - Lee, Kyoungmi AU - Parsons, Gregory N. T2 - CHEMSUSCHEM AB - Abstract Dye‐sensitized solar cells (DSSCs) often use a thin insulating or semiconducting layer (typically TiO 2 ) between the transparent conductive oxide and the mesoporous TiO 2 to block electron/hole recombination at the conducting oxide/electrolyte interface. The blocking layer (BL) is essential to maintain efficient charge generation under low light conditions, at which DSSCs perform well compared to common semiconductor‐based photovoltaic devices. In this work, we show that atomic layer deposition (ALD) can produce ultrathin (<10 nm) BLs that significantly impede charge recombination in functional DSSCs, leading to improved photocurrents, open‐circuit photovoltages, and fill factors; this results in an increase in the overall efficiency from ≈7 % to ≈8.4 % under AM 1.5 G illumination. The 5–10 nm ALD BLs are the thinnest optimized DSSC BLs reported to date. The BL retards the open‐circuit voltage decay and extends the electron lifetime from ≈0.2 s to more than 10 s at 0.3 V, confirming that the ALD films significantly impede photogenerated charge recombination. By preparing BLs through other deposition techniques, we directly demonstrate that ALD results in better performance, even with thinner films, which is ascribed to the lower pinhole density of ALD materials. DA - 2013/6// PY - 2013/6// DO - 10.1002/cssc.201300067 VL - 6 IS - 6 SP - 1014-1020 SN - 1864-564X UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000319828000011&KeyUID=WOS:000319828000011 KW - atomic layer deposition KW - blocking KW - dye-sensitized solar cells KW - electrochemistry KW - titanium ER - TY - JOUR TI - Synthesis and characterization of monodisperse uniformly shaped respirable aerosols AU - Fromen, Catherine A. AU - Shen, Tammy W. AU - Larus, Abigail E. AU - Mack, Peter AU - Maynor, Benjamin W. AU - Luft, J. Christopher AU - DeSimone, Joseph M. T2 - AICHE JOURNAL AB - The top‐down, micromolding technique, referred to as Particle Replication in Nonwetting Templates (PRINT ® ), affords a new opportunity for the generation of inhalation therapeutics. Powders were fabricated with predetermined particle size and shape; when dispersed with a collision jet nebulizer, these particles resulted in monodisperse aerosols with geometric standard deviations well below 1.2. Dynamic shape factors for this novel set of uniformly shaped particles were determined by correcting the drag of nonspherical particles in the ultra‐Stokesian flow conditions of the aerodynamic particle sizer (APS). This convenient approach for shape factor determination agreed well with current literature approaches and allowed for the correction of APS results for particles with known volumes. Determined shape factor values of PRINT geometries were used to estimate the theoretical median aerodynamic diameters of individual aerosols, which were then compared to actual inhalation powders. © 2013 American Institute of Chemical Engineers AIChE J , 59: 3184–3194, 2013 DA - 2013/9// PY - 2013/9// DO - 10.1002/aic.14157 VL - 59 IS - 9 SP - 3184-3194 SN - 1547-5905 KW - aerosols KW - biomedical engineering KW - nanotechnology KW - particle technology KW - particle KW - count KW - measurements ER - TY - JOUR TI - Stimuli-responsive copolymer solution and surface assemblies for biomedical applications AU - Kelley, E. G. AU - Albert, J. N. L. AU - Sullivan, M. O. AU - Epps, T. H. T2 - Chemical Society Reviews DA - 2013/// PY - 2013/// VL - 42 IS - 17 SP - 7057-7071 ER - TY - JOUR TI - Specificity and Regenerability of Short Peptide Ligands Supported on Polymer Layers for Immunoglobulin G Binding and Detection AU - Zhang, Yanxia AU - Islam, Nafisa AU - Carbonell, Ruben G. AU - Rojas, Orlando J. T2 - ACS APPLIED MATERIALS & INTERFACES AB - We demonstrate the specificity, regenerability, and excellent storage stability of short peptide-based systems for detection of immunoglobulin G (IgG). The bioactive component consisted of acetylated-HWRGWVA (Ac-HWRGWVA), a peptide with high IgG binding affinity, which was immobilized onto copolymer matrixes of poly(2-aminoethyl methacrylate hydrochloride-co-2-hydroxyethyl methacrylate) (poly(AMA-co-HEMA)). Surface plasmon resonance (SPR) and quartz crystal microgravimetry (QCM) were utilized with other complementary techniques to systematically investigate interfacial activities, mainly IgG binding performance as a function of the graft density and degree of polymerization of the poly(AMA-co-HEMA) support layer. Results from sodium dodecyl sulfate polyacrylamide gel electrophoresis and fluorescence microscopy indicate that the bioactive system is highly specific to IgG and resistant to nonspecific interactions when tested in mixed protein solutions. DA - 2013/8/28/ PY - 2013/8/28/ DO - 10.1021/am4021186 VL - 5 IS - 16 SP - 8030-8037 SN - 1944-8244 KW - short peptide ligands KW - immunoglobulin G detection KW - surface plasmon resonance KW - quartz crystal microgravimetry KW - regenerability KW - storage stability ER - TY - JOUR TI - Regenerable Photovoltaic Devices with a Hydrogel-Embedded Microvascular Network AU - Koo, Hyung-Jun AU - Velev, Orlin D. T2 - SCIENTIFIC REPORTS AB - Light-driven degradation of photoactive molecules could be one of the major obstacles to stable long term operation of organic dye-based solar light harvesting devices. One solution to this problem may be mimicking the regeneration functionality of a plant leaf. We report an organic dye photovoltaic system that has been endowed with such microfluidic regeneration functionality. A hydrogel medium with embedded channels allows rapid and uniform supply of photoactive reagents by a convection-diffusion mechanism. A washing-activation cycle enables reliable replacement of the organic component in a dye-sensitized photovoltaic system. Repetitive restoration of photovoltaic performance after intensive device degradation is demonstrated. DA - 2013/8/5/ PY - 2013/8/5/ DO - 10.1038/srep02357 VL - 3 SP - SN - 2045-2322 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84881402485&partnerID=MN8TOARS ER - TY - JOUR TI - Preservation of H-2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures AU - Piskorska, M. AU - Soule, T. AU - Gosse, J. L. AU - Milliken, C. AU - Flickinger, M. C. AU - Smith, G. W. AU - Yeager, C. M. T2 - MICROBIAL BIOTECHNOLOGY AB - To assess the applicability of latex cell coatings as an 'off-the-shelf' biocatalyst, the effect of osmoprotectants, temperature, humidity and O₂ on preservation of H₂ production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H₂ production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H₂ production activity, whereas considerable H₂ production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H₂ production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H₂ (0-0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27-53% of their H₂ production activity after 8 weeks of storage. When stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H₂ production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state. DA - 2013/9// PY - 2013/9// DO - 10.1111/1751-7915.12032 VL - 6 IS - 5 SP - 515-525 SN - 1751-7907 ER - TY - JOUR TI - Peptide-based affinity adsorbents with high binding capacity for the purification of monoclonal antibodies AU - Kish, W. S. AU - Naik, A. D. AU - Menegatti, S. AU - Carbonell, R. G. T2 - Industrial & Engineering Chemistry Research AB - High binding capacity and selectivity are key features for the successful application of affinity adsorbents for antibody purification. This study presents the development of affinity resins based on hexapeptide ligand HWRGWV for recovering monoclonal antibodies from cell culture fluids. Methods are presented for the immobilization of the peptide ligand and its variants on polymethacrylate and agarose based chromatographic supports using two main coupling strategies. The first one involves the formation of a peptide bond between the amino groups on the substrate and the peptide C-terminus activated with the uronium coupling agent HATU. The second approach involves resin activation with iodoacetic acid, followed by coupling of a cysteine-terminated variant of the ligand to form a thioether bond. The reaction conditions of peptide coupling were optimized to maximize the binding capacity of the resulting adsorbents. The peptide resins were characterized by measuring their static IgG binding capacities. The measured static binding capacity ranged from 35 to 48 mg/mL. The dynamic binding capacities (DBC) of four selected adsorbents were also determined, and they ranged from of 35 to 42 mg/mL with a 5-min residence time. All the resins exhibited high selectivity toward the Fc fragment of IgG. The affinity resins were used to purify two MAbs, a chimeric IgG1 and a humanized IgG4, from commercial CHO cell culture fluids. The resulting yields and purities for both MAbs were found to be in the range of 87–93% and >94%, respectively, which compare well with the purity and yield values obtained using commercially available Protein A media. Finally, the peptide resin with the highest IgG binding capacity, HWRGWVC-WorkBeads, was tested for 20 DBC cycles which included cleaning in place with 0.1 M NaOH after every cycle. The resin showed a high degree of reusability and alkaline stability, as it maintained 90% of its initial capacity. DA - 2013/// PY - 2013/// DO - 10.1021/ie302345w VL - 52 IS - 26 SP - 8800–8811 ER - TY - JOUR TI - PATCHY NANOPARTICLES Curvature makes a difference AU - Velev, Orlin D. T2 - NATURE NANOTECHNOLOGY DA - 2013/9// PY - 2013/9// DO - 10.1038/nnano.2013.173 VL - 8 IS - 9 SP - 620-621 SN - 1748-3387 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84883740888&partnerID=MN8TOARS ER - TY - JOUR TI - Oxygen Electroreduction on Ti- and Fe-Containing Carbon Fibers AU - McClure, Joshua P. AU - Devine, Christina K. AU - Jiang, Rongzhong AU - Chu, Deryn AU - Cuomo, Jerome J. AU - Parsons, Gregory N. AU - Fedkiw, Peter S. T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - A mixture of iron (II) phthalocyanine and polyacrylonitrile (PAN) was electrospun into fibers and pyrolyzed to form Fe-containing carbon fibers (Fe-PAN). Subsequent atomic layer deposition (ALD) coated the fibers with TiOy deposits (TiOy-Fe-PAN). Scanning transmission electron microscopy equipped with energy dispersive spectroscopy (STEM-EDS) detected C, Fe, and Ti across the diameter of the fiber, and X-ray photoelectron spectroscopy (XPS) revealed Fe(III) and CNx species present. After the ALD process, XPS revealed TiOy species on the Fe-PAN fibers, and heat-treating the TiOy-Fe-PAN samples created TiNxOy and TiNx species. Heat-treating Fe-PAN and TiOy-Fe-PAN samples resulted in a slight decrease in the Fe wt.% but affected an increase in the oxygen reduction reaction (ORR) activity in 0.5M H2SO4 at room temperature compared to the samples not heat treated. Moreover, the presence of Ti species decreased the production of H2O2 and increased the mass activity of the ORR on fibers subjected to cyclic potential excursions relative to samples without Ti species. DA - 2013/// PY - 2013/// DO - 10.1149/2.029308jes VL - 160 IS - 8 SP - F769-F778 SN - 1945-7111 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000324810000079&KeyUID=WOS:000324810000079 ER - TY - JOUR TI - Nanoparticle drug loading as a design parameter to improve docetaxel pharmacokinetics and efficacy AU - Chu, Kevin S. AU - Schorzman, Allison N. AU - Finniss, Mathew C. AU - Bowerman, Charles J. AU - Peng, Lei AU - Luft, James C. AU - Madden, Andrew J. AU - Wang, Andrew Z. AU - Zamboni, William C. AU - DeSimone, Joseph M. T2 - BIOMATERIALS AB - Nanoparticle (NP) drug loading is one of the key defining characteristics of an NP formulation. However, the effect of NP drug loading on therapeutic efficacy and pharmacokinetics has not been thoroughly evaluated. Herein, we characterized the efficacy, toxicity and pharmacokinetic properties of NP docetaxel formulations that have differential drug loading but are otherwise identical. Particle Replication in Non-wetting Templates (PRINT®), a soft-lithography fabrication technique, was used to formulate NPs with identical size, shape and surface chemistry, but with variable docetaxel loading. The lower weight loading (9%-NP) of docetaxel was found to have a superior pharmacokinetic profile and enhanced efficacy in a murine cancer model when compared to that of a higher docetaxel loading (20%-NP). The 9%-NP docetaxel increased plasma and tumor docetaxel exposure and reduced liver, spleen and lung exposure when compared to that of 20%-NP docetaxel. DA - 2013/11// PY - 2013/11// DO - 10.1016/j.biomaterials.2013.07.038 VL - 34 IS - 33 SP - 8424-8429 SN - 1878-5905 KW - Soft-lithography KW - Docetaxel KW - Polylactic acid KW - Drug loading KW - Pharmacokinetics ER - TY - JOUR TI - N-Alkyl-N-methylpyrrolidinium difluoro(oxalato)borate ionic liquids: Physical/electrochemical properties and Al corrosion AU - Allen, J. L. AU - McOwen, D. W. AU - Delp, S. A. AU - Fox, E. T. AU - Dickmann, J. S. AU - Han, S. D. AU - Zhou, Z. B. AU - Jow, T. R. AU - Henderson, W. A. T2 - Journal of Power Sources DA - 2013/// PY - 2013/// VL - 237 SP - 104-111 ER - TY - JOUR TI - Multi-stimuli responsive foams combining particles and self-assembling fatty acids AU - Fameau, Anne-Laure AU - Lam, Stephanie AU - Velev, Orlin D. T2 - CHEMICAL SCIENCE AB - Foams that respond to external stimuli are a new type of highly functional soft matter and an emerging research subject in the field of materials and colloid science. Herein, we report a new way to control foam stability using light irradiation. This unconventional approach involves a combination of the thermal response of a fatty acid and the ability of carbon black to convert light stimulus to heat. This simple system features both high foamability and high foam stability, but can easily be destroyed by light. Upon exposure to UV or solar illumination, the carbon black particles absorb light causing an increase in temperature inside the foam lamella. This results in a transition of the fatty acid assemblies from tubes, which stabilize the foam films, to micelles, leading to rapid foam destabilization. The foam destabilization rate under UV irradiation was correlated to foam liquid fraction, fatty acid concentration, as well as carbon black concentration. Our approach for the formulation of photo-thermo-responsive foams could be easily generalized and extended to magnetic particles, giving rise to the first foams exhibiting thermo-photo-magneto-tuneable stability. Such multi-stimuli responsive systems can find applications in diverse industries requiring highly stable systems which can be destroyed on-demand. DA - 2013/// PY - 2013/// DO - 10.1039/c3sc51774h VL - 4 IS - 10 SP - 3874-3881 SN - 2041-6539 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84883269113&partnerID=MN8TOARS ER - TY - JOUR TI - Future of the Particle Replication in Nonwetting Templates (PRINT) Technology AU - Xu, Jing AU - Wong, Dominica H. C. AU - Byrne, James D. AU - Chen, Kai AU - Bowerman, Charles AU - DeSimone, Joseph M. T2 - ANGEWANDTE CHEMIE-INTERNATIONAL EDITION AB - Particle replication in nonwetting templates (PRINT) is a continuous, roll-to-roll, high-resolution molding technology which allows the design and synthesis of precisely defined micro- and nanoparticles. This technology adapts the lithographic techniques from the microelectronics industry and marries these with the roll-to-roll processes from the photographic film industry to enable researchers to have unprecedented control over particle size, shape, chemical composition, cargo, modulus, and surface properties. In addition, PRINT is a GMP-compliant (GMP=good manufacturing practice) platform amenable for particle fabrication on a large scale. Herein, we describe some of our most recent work involving the PRINT technology for application in the biomedical and material sciences. DA - 2013/// PY - 2013/// DO - 10.1002/anie.201209145 VL - 52 IS - 26 SP - 6580-6589 SN - 1521-3773 KW - colloids KW - drug delivery KW - nanomedicine KW - nanoparticles KW - soft lithography ER - TY - JOUR TI - Frontiers in thin film epitaxy and nanostructured materials introduction AU - Narayan, J. AU - Schwartz, J. AU - Goyal, A. AU - Wang, H. Y. AU - Jin, S. H. AU - Liao, X. Z. T2 - Journal of Materials Research DA - 2013/// PY - 2013/// VL - 28 IS - 13 SP - 1625-1625 ER - TY - JOUR TI - Field-directed assembly of patchy anisotropic microparticles with defined shape AU - Shields, C. Wyatt AU - Zhu, Shan AU - Yang, Ye AU - Bharti, Bhuvnesh AU - Liu, Jonathan AU - Yellen, Benjamin B. AU - Velev, Orlin D. AU - Lopez, Gabriel P. T2 - SOFT MATTER AB - Electromagnetic fields can generate orientation-dependent, long range interactions between colloidal components that direct their assembly into highly ordered structures, such as small ordered clusters, chains, and large crystalline lattices. While much effort has been devoted to exploring the assembly of spherical colloids, few reports have investigated the directed assembly of non-spherical particles with Janus or patchy morphologies. Here, we use photolithographic techniques to fabricate a wide range of anisotropically shaped patchy particles and follow their assembly in liquid suspensions under the influence of electric and magnetic fields. We analyze the assembly of several types of patchy particles across a range of field parameters and fluid compositions, and report a number of distinct, well-ordered, assembly architectures including cylindrical, prismatic, and staggered chains. The structures assembled from anisotropic patchy components provide a glimpse into the range of architectures that can be created by combining field directed assembly with rationally designed particles. By using numerical simulations to model the electric and magnetic field interactions between these particles, we interpret the results of the assembly process and explain how they can be controlled by the position of the metal facet, the frequency (for AC fields), or magnetic susceptibility of the medium. The resulting structures, and similar ones produced through the field-directed assembly of patchy anisotropic particles, can possess unique electrical and optical properties and may have potential applications in a number of future technology applications such as microactuators, metamaterials and multiferroic materials. DA - 2013/// PY - 2013/// DO - 10.1039/c3sm51119g VL - 9 IS - 38 SP - 9219-9229 SN - 1744-6848 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84884128329&partnerID=MN8TOARS ER - TY - JOUR TI - Electrolyte solvation and ionic association III. Acetonitrile-lithium salt mixtures-transport properties AU - Seo, D. M. AU - Borodin, O. AU - Balogh, D. AU - O'Connell, M. AU - Ly, Q. AU - Han, S. D. AU - Passerini, S. AU - Henderson, W. A. T2 - Journal of the Electrochemical Society DA - 2013/// PY - 2013/// VL - 160 IS - 8 SP - A1061-1070 ER - TY - JOUR TI - Bi-layer Al2O3/ZnO atomic layer deposition for controllable conductive coatings on polypropylene nonwoven fiber mats AU - Sweet, William J., III AU - Jur, Jesse S. AU - Parsons, Gregory N. T2 - JOURNAL OF APPLIED PHYSICS AB - Electrically conductive zinc oxide coatings are applied to polypropylene nonwoven fiber mats by atomic layer deposition (ALD) at 50–155 °C. A low temperature (50 °C) aluminum oxide ALD base layer on the polypropylene limits diffusion of diethyl zinc into the polypropylene, resulting in ZnO layers with properties similar to those on planar silicon. Effective conductivity of 63 S/cm is achieved for ZnO on Al2O3 coated polypropylene fibers, and the fibers remain conductive for months after coating. Without the Al2O3 precoating, the effective conductivity was much smaller, consistent with precursor diffusion into the polymer and sub-surface ZnO nucleation. Mechanical robustness tests showed that conductive samples bent around a 6 mm radius maintained up to 40% of the pre-bending conductivity. Linkages between electrical conductivity and mechanical performance will help inform materials choice for flexible and porous electronics including textile-based sensors and antennas. DA - 2013/5/21/ PY - 2013/5/21/ DO - 10.1063/1.4804960 VL - 113 IS - 19 SP - SN - 0021-8979 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000319295200047&KeyUID=WOS:000319295200047 ER - TY - JOUR TI - Understanding and exploiting feedback in synthetic biology AU - Afroz, Taliman AU - Beisel, Chase L. T2 - CHEMICAL ENGINEERING SCIENCE AB - Synthetic biology employs traditional engineering concepts in the construction of cells and organisms. One of the most fundamental concepts is feedback, where the activity of a system is influenced by its output. Feedback can imbue the system with a range of desirable properties such as reducing the rise time or exhibiting an ultrasensitive response. Feedback is also commonly found in nature, further supporting the incorporation of feedback into synthetic biological systems. In this review, we discuss the common attributes of negative and positive feedback loops in gene regulatory networks, whether alone or in combination, and describe recent applications of feedback in metabolic engineering, population control, and the development of advanced biosensors. The examples principally come from synthetic systems in the bacterium Escherichia coli and in the budding yeast Saccharomyces cerevisiae, the two major workhorses of synthetic biology. Through this review, we argue that biological feedback represents a powerful yet underutilized tool that can advance the construction of biological systems. DA - 2013/11/15/ PY - 2013/11/15/ DO - 10.1016/j.ces.2013.02.017 VL - 103 SP - 79-90 SN - 1873-4405 KW - Biological engineering KW - Feedback KW - Genetic circuit KW - Mathematical modeling KW - Process control KW - Synthetic biology ER - TY - JOUR TI - The unusual interactions between polymer grafted cellulose nanocrystal aggregates AU - Rojas, Orlando J. AU - Lokanathan, Arcot R. AU - Kontturi, Eero AU - Laine, Janne AU - Bock, Henry T2 - SOFT MATTER AB - Using computer simulations we study how a corona of polymer molecules grafted to cellulose nanocrystal aggregate (CNA) particles influences the interaction between pairs of parallel CNAs. The resulting distance and orientation (face-to-face versus edge-to-edge) dependence is very rich and counterintuitive. Although the unperturbed polymer corona assumes cylindrical symmetry relatively quickly as the degree of polymerisation increases, the polymer mediated interactions between the grafted particles are strongly orientation dependent. Rather unexpectedly we find that the forces in the face-to-face orientation are much larger than in the edge-to-edge configuration although in the latter case the distance between the particle surfaces is much smaller. The reason for this effect is that overall the face-to-face orientation leads to larger chain confinement. Interestingly, we find that the deviations of the polymer mediated interactions from cylindrical symmetry are larger in the case of longer grafted molecules compared to shorter ones. When the distance between the CNAs becomes larger and the overlap of the polymer coronas becomes small, the orientation dependence of the mediated interaction vanishes and the particles behave as cylindrical rods. However, this is only a crossover point where the behaviour of the system inverts to slightly larger forces in the edge-to-edge compared to the face-to-face configuration. Thus, even though the polymer density around the CNAs is nearly perfectly cylindrically symmetric the polymer mediated interactions are strongly orientation dependent, revealing the polygon character of the CNA cross-section. DA - 2013/// PY - 2013/// DO - 10.1039/c3sm51494c VL - 9 IS - 37 SP - 8965-8973 SN - 1744-683X ER - TY - JOUR TI - Synthesis and properties of Li2MnO3-based cathode materials for lithium-ion batteries AU - Xue, Leigang AU - Zhang, Shu AU - Li, Shuli AU - Lu, Yao AU - Toprakci, Ozan AU - Xia, Xin AU - Chen, Chen AU - Hu, Yi AU - Zhang, Xiangwu T2 - JOURNAL OF ALLOYS AND COMPOUNDS AB - Lithium-ion batteries have been wildly used in various portable electronic devices and the application targets are currently moving from small-sized mobile devices to large-scale electric vehicles and grid energy storage. Therefore, lithium-ion batteries with higher energy densities are in urgent need. For high-energy cathodes, Li2MnO3–LiMO2 layered–layered (M = Mn, Co, Ni) materials are of significant interest due to their high specific capacities over wide operating potential windows. Here, three Li2MnO3-based cathode materials with α-NaFeO2 structure were prepared by a facile co-precipitation method and subsequent heat treatment. Among these three materials, 0.3Li2MnO3·0.5LiMn0.5Ni0.5O2·0.2LiCoO2 shows the best lithium storage capability. This cathode material is composed of uniform nanosized particles with diameters ranging from 100 to 200 nm, and it could be charged to a high cutoff potential to extract more lithium, resulting in a high capacity of 178 mAh g−1 between 2.0 and 4.6 V with almost no capacity loss over 100 cycles. DA - 2013/11/15/ PY - 2013/11/15/ DO - 10.1016/j.jallcom.2013.07.029 VL - 577 SP - 560-563 SN - 1873-4669 UR - https://publons.com/publon/674387/ KW - Cathode material KW - Li2MnO3 KW - High capacity KW - Structure stability KW - Cycling performance ER - TY - JOUR TI - Soy protein-nanocellulose composite aerogels AU - Arboleda, Julio C. AU - Hughes, Mark AU - Lucia, Lucian A. AU - Laine, Janne AU - Ekman, Kalle AU - Rojas, Orlando J. T2 - CELLULOSE DA - 2013/10// PY - 2013/10// DO - 10.1007/s10570-013-9993-4 VL - 20 IS - 5 SP - 2417-2426 SN - 0969-0239 KW - Composite aerogels KW - Soy proteins KW - Nanocellulose KW - Cellulose nanofibrils KW - Freeze casting KW - Nanofibrillated cellulose KW - Microfibrillated cellulose (MFC) KW - NFC KW - Porous solids ER - TY - JOUR TI - On the molecular origin of high-pressure effects in nanoconfinement: The role of surface chemistry and roughness AU - Long, Yun AU - Palmer, Jeremy C. AU - Coasne, Benoit AU - Sliwinska-Bartkowiak, Malgorzata AU - Jackson, George AU - Mueller, Erich A. AU - Gubbins, Keith E. T2 - The Journal of Chemical Physics AB - Experiments and simulations both suggest that the pressure experienced by an adsorbed phase confined within a carbon nanoporous material can be several orders of magnitude larger than the bulk phase pressure in equilibrium with the system. To investigate this pressure enhancement, we report a molecular-simulation study of the pressure tensor of argon confined in slit-shaped nanopores with walls of various models, including carbon and silica materials. We show that the pressure is strongly enhanced by confinement, arising from the effect of strongly attractive wall forces; confinement within purely repulsive walls does not lead to such enhanced pressures. Simulations with both the Lennard-Jones and Barker-Fisher-Watts intermolecular potentials for argon-argon interactions give rise to similar results. We also show that an increase in the wall roughness significantly decreases the in-pore pressure due to its influence on the structure of the adsorbate. Finally, we demonstrate that the pressures calculated from the mechanical (direct pressure tensor calculations) and the thermodynamic (volume perturbation method) routes yield almost identical results, suggesting that both methods can be used to calculate the local pressure tensor components in the case of these planar geometries. DA - 2013/10/14/ PY - 2013/10/14/ DO - 10.1063/1.4824125 VL - 139 IS - 14 SP - 144701 J2 - The Journal of Chemical Physics LA - en OP - SN - 0021-9606 1089-7690 UR - http://dx.doi.org/10.1063/1.4824125 DB - Crossref ER - TY - JOUR TI - Microfluidic channels fabricated from poly(vinylmethylsiloxane) networks that resist swelling by organic solvents AU - Mays, Robin L. AU - Dickey, Michael D. AU - Genzer, Jan T2 - LAB ON A CHIP AB - This paper describes the use of poly(vinylmethylsiloxane) (PVMS) networks for fabricating microfluidic channels that resist swelling in the presence of organic solvents, thus providing a versatile alternative to poly(dimethylsiloxane) (PDMS). In particular, we demonstrate that in contrast to PDMS microchannels, the UV-treated PVMS structures exhibit high resistance to swelling by toluene. DA - 2013/// PY - 2013/// DO - 10.1039/c3lc50848j VL - 13 IS - 22 SP - 4317-4320 SN - 1473-0189 ER - TY - JOUR TI - History of atomic layer deposition and its relationship with the American Vacuum Society AU - Parsons, Gregory N. AU - Elam, Jeffrey W. AU - George, Steven M. AU - Haukka, Suvi AU - Jeon, Hyeongtag AU - Kessels, W. M. M. AU - Leskela, Markku AU - Poodt, Paul AU - Ritala, Mikko AU - Rossnagel, Steven M. T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - This article explores the history of atomic layer deposition(ALD) and its relationship with the American Vacuum Society (AVS). The authors describe the origin and history of ALD science in the 1960s and 1970s. They also report on how the science and technology of ALD progressed through the 1990s and 2000s and continues today. This article focuses on how ALD developed within the AVS and continues to evolve through interactions made possible by the AVS, in particular, the annual International AVS ALD Conference. This conference benefits students, academics, researchers, and industry practitioners alike who seek to understand the fundamentals of self-limiting, alternating binary surface reactions, and how they can be applied to form functional (and sometimes profitable) thin filmmaterials. The flexible structure of the AVS allowed the AVS to quickly organize the ALD community and create a primary conference home. Many new research areas have grown out of the original concepts of “Atomic Layer Epitaxy” and“Molecular Layering,” and some of them are described in this article. The people and research in the ALD field continue to evolve, and the AVS ALDConference is a primary example of how the AVS can help a field expand and flourish. DA - 2013/9// PY - 2013/9// DO - 10.1116/1.4816548 VL - 31 IS - 5 SP - SN - 1520-8559 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000324388800018&KeyUID=WOS:000324388800018 ER - TY - JOUR TI - Graphene-coated pyrogenic carbon as an anode material for lithium battery AU - Zhang, Ming AU - Gao, Bin AU - Li, Ying AU - Zhang, Xiangwu AU - Hardin, Ian R. T2 - CHEMICAL ENGINEERING JOURNAL AB - Abstract In this work, cotton fibers and pyrene-dispersed graphene sheets were used to produce graphene-coated pyrogenic carbon as an anode material for lithium battery. The graphene sheets were wrapped around the cotton fibers by simply dipping the fabric in a graphene/pyrene-derivative suspension. And then the cotton/graphene textile was annealed at 700 °C in a quartz tube furnace under Ar flow conditions. During the annealing process, the gaps between separated graphene sheets were “soldered” by “glue” molecules (aromatic molecular surfactant) to form graphene-coated pyrogenic carbon. Because of the unique electric properties of the graphene “skin” on the pyrogenic carbon, the flexible graphene-coated pyrogenic carbon showed relatively large storage capacity to lithium. Galvanostatic charge–discharge experiments also showed that the graphene-coated pyrogenic carbon electrode provided a reversible discharge capacity as high as 288 mA h g−1 even after 50 cycles and thus can be used an anode material in lithium battery. DA - 2013/8/1/ PY - 2013/8/1/ DO - 10.1016/j.cej.2013.06.025 VL - 229 SP - 399-403 SN - 1385-8947 UR - https://publons.com/publon/7178361/ KW - Graphene KW - Pyrogenic carbon KW - Cotton fibers KW - Annealing KW - Lithium battery ER - TY - JOUR TI - From Core-Shell to Alloys: The Preparation and Characterization of Solution-Synthesized AuPd Nanoparticle Catalysts AU - Wilson, Adria R. AU - Sun, Keyi AU - Chi, Miaofang AU - White, Ryan M. AU - LeBeau, James M. AU - Lamb, H. Henry AU - Wiley, Benjamin J. T2 - JOURNAL OF PHYSICAL CHEMISTRY C AB - This article describes the solution-phase synthesis of 4 nm gold nanoparticles with 0.7 atom-thick, 1.9 atom-thick, and 3.8 atom-thick layers of Pd on their surfaces. These well-defined core–shell nanoparticles were deposited on a silica support, calcined, and reduced at 300 °C to create alloyed nanoparticles containing 10.9, 20.2, and 28.5% Pd (w/w). Monometallic Pd nanoparticles sintered during calcination at 300 °C, but no sintering was observed for AuPd nanoparticles. Diffuse reflectance infrared Fourier transform (DRIFT) spectra of adsorbed CO suggests that Au donates d electron density to Pd in the core–shell and alloy structures and confirms the presence of Au and Pd atoms on the surface of the nanoparticles after calcination and reduction. The properties of the AuPd alloy catalysts were tested in the vapor-phase conversion of α-limonene to p-cymene. AuPd nanoparticles containing 20% or more Pd per particle produced p-cymene yields greater than 80%, equivalent to conventional Pd catalysts prepared by incipient wetness and ion exchange methods. Very low yields of p-cymene were obtained from dehydrogenation of p-menthane under equivalent conditions, suggesting that the production of p-cymene from α-limonene proceeds through terpinene intermediates. DA - 2013/8/29/ PY - 2013/8/29/ DO - 10.1021/jp404157m VL - 117 IS - 34 SP - 17557-17566 SN - 1932-7447 ER - TY - JOUR TI - Biomimetic photocatalytic reactor with a hydrogel-embedded microfluidic network AU - Koo, Hyung-Jun AU - Velev, Orlin D. T2 - JOURNAL OF MATERIALS CHEMISTRY A AB - We present a light driven biomimetic reactor where photocatalytic TiO2 nanoparticles are embedded into water-based gels. Uniform supply of the reactants and extraction of the products is accomplished via a microfluidic channel network in a permeable hydrogel, broadly similar to the vein structure of live leaves. Quantitative analysis shows that the microvascular reactor has high quantum efficiency per mass of the catalyst. DA - 2013/// PY - 2013/// DO - 10.1039/c3ta12483e VL - 1 IS - 37 SP - 11106-11110 SN - 2050-7496 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84883295175&partnerID=MN8TOARS ER - TY - JOUR TI - Analysis of compound weighing precision in drug discovery AU - Popa-Burke, I. AU - Novick, S. AU - Mantilla, M. AU - McGrath, K. T2 - Journal of Biomolecular Screening DA - 2013/// PY - 2013/// VL - 18 IS - 3 SP - 331-340 ER - TY - JOUR TI - Ultrastretchable, cyclable and recyclable 1- and 2-dimensional conductors based on physically cross-linked thermoplastic elastomer gels AU - Mineart, Kenneth P. AU - Lin, Yiliang AU - Desai, Sharvil C. AU - Krishnan, Arjun S. AU - Spontak, Richard J. AU - Dickey, Michael D. T2 - SOFT MATTER AB - Stretchable conductors maintain electrical conductivity at large strains relative to their rigid counterparts that fail at much lower strains. Here, we demonstrate ultrastretchable conductors that are conductive to at least 600% strain and may be strain-cycled without significant degradation to the mechanical or electrical properties. The conductors consist of a liquid metal alloy injected into microchannels composed of triblock copolymer gels. Rheological measurements identify the temperature window over which these gels may be molded and laminated to form microchannels without collapsing the microscale features. Mechanical measurements identify the gel composition that represents a compromise between minimizing modulus (to allow the polymer to be stretched with ease) and maximizing interfacial adhesion strength at the laminated polymer–polymer interface. The resulting 2D stretchable conductors are notable for their ability to maintain electrical conductivity up to large strains, their mechanical durability, and their ability to be recycled easily with full recovery of the component species. DA - 2013/// PY - 2013/// DO - 10.1039/c3sm51136g VL - 9 IS - 32 SP - 7695-7700 SN - 1744-6848 ER - TY - JOUR TI - Synthesis and characterization of silver/lithium cobalt oxide (Ag/LiCoO2) nanofibers via sol-gel electrospinning AU - Aykut, Yakup AU - Pourdeyhimi, Behnam AU - Khan, Saad A. T2 - JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS AB - We report on the preparation and characterization of Ag/LiCoO2 nanofibers (NFs) via the sol–gel electrospinning (ES) technique. Ag nanoparticles (NPs) were produced in an aqueous polyvinyl pyrrolidone (PVP) solution by using AgNO3 precursor. A viscous lithium acetate/cobalt acetate/polyvinylalcohol/water (LiAc/(CoAc)2/PVA/water) solution was prepared separately. A Ag NPs/PVP/water solution was prepared and added to this viscous solution and magnetically stirred to obtain the final homogeneous electrospinning solution. After establishing the proper electrospinning conditions, as-spun precursor Ag/LiAc/Co(Ac)2/PVA/PVP NFs were formed and calcined in air at a temperature of 600 °C for 3 h to form well-crystallized porous Ag/LiCoO2 NFs. Various analytical characterization techniques such as UV–vis, SEM, TEM, TGA, XRD, and XPS were performed to analyze Ag NPs, as-spun and calcined NFs. It was established that Ag NPs in the precursor Ag/LiAc/Co(Ac)2/PVA/PVP NFs are highly self-aligned as a result of the behavior of Ag in the electric field of the electrospinning setup and the interaction of Ag ions with Li and Co ions in the NF. Ag/LiCoO2 NFs exhibit a nanoporous structure compared with un-doped LiCoO2 NFs because the atomic radius of Ag is larger than the radius of Co and Li ion; thus, no substitution between Ag and Li or Ag and Co atoms occurs, and Ag NPs are located at the interlayer of LiCoO2 while some are left in the fiber. DA - 2013/11// PY - 2013/11// DO - 10.1016/j.jpcs.2013.05.021 VL - 74 IS - 11 SP - 1538-1545 SN - 1879-2553 KW - Nanostructures KW - Sol-gel growth KW - Crystal structure KW - Microstructure ER - TY - JOUR TI - Stationary Phase and Nutrient Levels Trigger Transcription of a Genomic Locus Containing a Novel Peptide (TM1316) in the Hyperthermophilic Bacterium Thermotoga maritima AU - Frock, Andrew D. AU - Montero, Clemente I. AU - Blumer-Schuette, Sara E. AU - Kelly, Robert M. T2 - APPLIED AND ENVIRONMENTAL MICROBIOLOGY AB - ABSTRACT The genome of the hyperthermophilic bacterium Thermotoga maritima encodes numerous putative peptides/proteins of 100 amino acids or less. While most of these open reading frames (ORFs) are transcribed during growth, their corresponding physiological roles are largely unknown. The onset of stationary phase in T. maritima was accompanied by significant morphological changes and upregulation of several ORFs located in the TM1298-TM1336 genome locus. This region contains putative HicAB toxin-antitoxin pairs, hypothetical proteins, radical S -adenosylmethionine (SAM) enzymes, and ABC transporters. Of particular note was the TM1315-TM1319 operon, which includes a putative 31-amino-acid peptide (TM1316) that was the most highly transcribed gene in the transcriptome during stationary phase. Antibodies directed against a synthetic version of TM1316 were used to track its production, which correlated closely with transcriptomic data. Immunofluorescence microscopy revealed that TM1316 was localized to the cell envelope and prominent in cell aggregates formed during stationary phase. The only functionally characterized locus with an organization similar to that of TM1315-TM1319 is in Bacillus subtilis , which contains subtilosin A, a cyclic peptide with Cys–to–α-carbon linkages that functions as an antilisterial bacteriocin. While the organization of TM1316 resembled that of the Bacillus peptide (e.g., in its number of amino acids and spacing of Cys residues), preparations containing high levels of TM1316 affected the growth of neither Thermotoga species nor Pyrococcus furiosus , a hyperthermophilic archaeon isolated from the same locale as T. maritima . Several other putative Cys-rich peptides could be identified in the TM1298-TM1336 locus, and while their roles are also unclear, they merit examination as potential antimicrobial agents in hyperthermophilic biotopes. DA - 2013/11// PY - 2013/11// DO - 10.1128/aem.01627-13 VL - 79 IS - 21 SP - 6637-6646 SN - 1098-5336 ER - TY - JOUR TI - Si/C composite nanofibers with stable electric conductive network for use as durable lithium-ion battery anode AU - Fu, Kun AU - Xue, Leigang AU - Yildiz, Ozkan AU - Li, Shuli AU - Lee, Hun AU - Li, Ying AU - Xu, Guanjie AU - Zhou, Lan AU - Bradford, Philip D. AU - Zhang, Xiangwu AU - al., T2 - NANO ENERGY AB - High-energy anode materials have attracted significant attention because of their potential applications in large-scale energy storage devices. However, they often suffer from rapid capacity fading due to the pulverization of the electrode and the breakdown of electric conductive network caused by the large volume changes of active material upon repeated lithium insertion and extraction. In this work, a new electrode composed of Si/C composite nanofibers was prepared, aiming at the improvement of cycling performance of Si anodes through the establishment of a stable electric conductive network for Si during cycling. By electrospinning, a three-dimensional network of carbon nanofibers, which possesses good elasticity to maintain the structure integrity and stable electric conductive network, is formed; by carbon coating, all Si nanoparticles are tightly bonded with carbon fibers to form a stable electric conductive pathway for electrode reactions. The nanofiber structure and the carbon coating on Si, combined with the binder, lead to a stable network structure that can accommodate the huge volume change of Si during the repeated volume expansion and contraction, thus resulting in excellent cycling performance. DA - 2013/5// PY - 2013/5// DO - 10.1016/j.nanoen.2012.11.001 VL - 2 IS - 3 SP - 361-367 SN - 2211-3282 UR - https://publons.com/publon/674385/ KW - Lithium-ion battery anode KW - Volume change KW - Electric conductive network KW - Cycling stability KW - Carbon coating KW - Nanofiber ER - TY - JOUR TI - Reversible patterning and actuation of hydrogels by electrically assisted ionoprinting AU - Palleau, Etienne AU - Morales, Daniel AU - Dickey, Michael D. AU - Velev, Orlin D. T2 - NATURE COMMUNICATIONS AB - The ability to pattern, structure, re-shape and actuate hydrogels is important for biomimetics, soft robotics, cell scaffolding and biomaterials. Here we introduce an 'ionoprinting' technique with the capability to topographically structure and actuate hydrated gels in two and three dimensions by locally patterning ions via their directed injection and complexation, assisted by electric fields. The ionic binding changes the local mechanical properties of the gel to induce relief patterns and, in some cases, evokes localized stress large enough to cause rapid folding. These ionoprinted patterns are stable for months, yet the ionoprinting process is fully reversible by immersing the gel in a chelator. The mechanically patterned hydrogels exhibit programmable temporal and spatial shape transitions, and serve as a basis for a new class of soft actuators that can gently manipulate objects both in air and in liquid solutions. DA - 2013/8// PY - 2013/8// DO - 10.1038/ncomms3257 VL - 4 IS - 1 SP - SN - 2041-1723 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84881440081&partnerID=MN8TOARS ER - TY - JOUR TI - Nanoparticle clearance is governed by Th1/Th2 immunity and strain background AU - Jones, Stephen W. AU - Roberts, Reid A. AU - Robbins, Gregory R. AU - Perry, Jillian L. AU - Kai, Marc P. AU - Chen, Kai AU - Bo, Tao AU - Napier, Mary E. AU - Ting, Jenny P. Y. AU - DeSimone, Joseph M. AU - Bear, James E. T2 - JOURNAL OF CLINICAL INVESTIGATION AB - Extended circulation of nanoparticles in blood is essential for most clinical applications. Nanoparticles are rapidly cleared by cells of the mononuclear phagocyte system (MPS). Approaches such as grafting polyethylene glycol onto particles (PEGylation) extend circulation times; however, these particles are still cleared, and the processes involved in this clearance remain poorly understood. Here, we present an intravital microscopy-based assay for the quantification of nanoparticle clearance, allowing us to determine the effect of mouse strain and immune system function on particle clearance. We demonstrate that mouse strains that are prone to Th1 immune responses clear nanoparticles at a slower rate than Th2-prone mice. Using depletion strategies, we show that both granulocytes and macrophages participate in the enhanced clearance observed in Th2-prone mice. Macrophages isolated from Th1 strains took up fewer particles in vitro than macrophages from Th2 strains. Treating macrophages from Th1 strains with cytokines to differentiate them into M2 macrophages increased the amount of particle uptake. Conversely, treating macrophages from Th2 strains with cytokines to differentiate them into M1 macrophages decreased their particle uptake. Moreover, these results were confirmed in human monocyte-derived macrophages, suggesting that global immune regulation has a significant impact on nanoparticle clearance in humans. DA - 2013/7// PY - 2013/7// DO - 10.1172/jci66895 VL - 123 IS - 7 SP - 3061-3073 SN - 1558-8238 ER - TY - JOUR TI - Ionic current devices-Recent progress in the merging of electronic, microfluidic, and biomimetic structures AU - Koo, Hyung-Jun AU - Velev, Orlin D. T2 - BIOMICROFLUIDICS AB - We review the recent progress in the emerging area of devices and circuits operating on the basis of ionic currents. These devices operate at the intersection of electrochemistry, electronics, and microfluidics, and their potential applications are inspired by essential biological processes such as neural transmission. Ionic current rectification has been demonstrated in diode-like devices containing electrolyte solutions, hydrogel, or hydrated nanofilms. More complex functions have been realized in ionic current based transistors, solar cells, and switching memory devices. Microfluidic channels and networks-an intrinsic component of the ionic devices-could play the role of wires and circuits in conventional electronics. DA - 2013/5// PY - 2013/5// DO - 10.1063/1.4804249 VL - 7 IS - 3 SP - SN - 1932-1058 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84880119681&partnerID=MN8TOARS ER - TY - JOUR TI - Image analysis and empirical modeling of gene and protein expression AU - Trisnadi, Nathanie AU - Altinok, Alphan AU - Stathopoulos, Angelike AU - Reeves, Gregory T. T2 - Methods AB - Protein gradients and gene expression patterns are major determinants in the differentiation and fate map of the developing embryo. Here we discuss computational methods to quantitatively measure the positions of gene expression domains and the gradients of protein expression along the dorsal-ventral axis in the Drosophila embryo. Our methodology involves three layers of data. The first layer, or the primary data, consists of z-stack confocal images of embryos processed by in situ hybridization and/or antibody stainings. The secondary data are relationships between location, usually an x-axis coordinate, and fluorescent intensity of gene or protein detection. Tertiary data comprise the optimal parameters that arise from fits of the secondary data to empirical models. The tertiary data are useful to distill large datasets of imaged embryos down to a tractable number of conceptually useful parameters. This analysis allows us to detect subtle phenotypes and is adaptable to any set of genes or proteins with a canonical pattern. For example, we show how insights into the Dorsal transcription factor protein gradient and its target gene ventral-neuroblasts defective (vnd) were obtained using such quantitative approaches. DA - 2013/7// PY - 2013/7// DO - 10.1016/j.ymeth.2012.09.016 VL - 62 IS - 1 SP - 68-78 J2 - Methods LA - en OP - SN - 1046-2023 UR - http://dx.doi.org/10.1016/j.ymeth.2012.09.016 DB - Crossref KW - Quantitative measurements KW - Gene expression KW - Protein gradient KW - Drosophila melanogaster KW - Dorsal-ventral patterning KW - Empirical modeling ER - TY - JOUR TI - Heat treatment of electrospun Polyvinylidene fluoride fibrous membrane separators for rechargeable lithium-ion batteries AU - Liang, Yinzheng AU - Cheng, Sichen AU - Zhao, Jianmeng AU - Zhang, Changhuan AU - Sun, Shiyuan AU - Zhou, Nanting AU - Qiu, Yiping AU - Zhang, Xiangwu T2 - JOURNAL OF POWER SOURCES AB - Polyvinylidene fluoride (PVDF) fibrous membranes for use as lithium-ion battery separators were prepared by electrospinning technique. Heat treatment was introduced to improve the tensile strength and elongation-at-break as well as the tensile modulus of PVDF fibrous membranes, with the best mechanical properties achieved after treatment at 160 °C for 2 h. After heat treatment at 160 °C for 2 h, the ionic conductivity of the liquid electrolyte-soaked PVDF fibrous membranes was 1.35 × 10−3 S cm−1 at room temperature. Moreover, compared with commercial Celgard 2400 separator, heat-treated PVDF fibrous membranes exhibited higher electrochemical stability window and lower interfacial resistance with lithium electrode. In addition, at a 0.2C rate, Li/LiFePO4 cells using heat-treated PVDF fibrous membrane separator showed high charge/discharge capacities and stable cycle performance. DA - 2013/10/15/ PY - 2013/10/15/ DO - 10.1016/j.jpowsour.2013.04.019 VL - 240 SP - 204-211 SN - 0378-7753 UR - https://publons.com/publon/7178365/ KW - Lithium-ion battery KW - Electrospinning KW - PVDF KW - Separator KW - Heat treatment ER - TY - JOUR TI - Fibroblast Migration Is Regulated by Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS) Protein AU - Ott, Laura E. AU - Sung, Eui Jae AU - Melvin, Adam T. AU - Sheats, Mary K. AU - Haugh, Jason M. AU - Adler, Kenneth B. AU - Jones, Samuel L. T2 - PLOS ONE AB - Myristoylated alanine-rich C-kinase substrate (MARCKS) is a ubiquitously expressed substrate of protein kinase C (PKC) that is involved in reorganization of the actin cytoskeleton. We hypothesized that MARCKS is involved in regulation of fibroblast migration and addressed this hypothesis by utilizing a unique reagent developed in this laboratory, the MANS peptide. The MANS peptide is a myristoylated cell permeable peptide corresponding to the first 24-amino acids of MARCKS that inhibits MARCKS function. Treatment of NIH-3T3 fibroblasts with the MANS peptide attenuated cell migration in scratch wounding assays, while a myristoylated, missense control peptide (RNS) had no effect. Neither MANS nor RNS peptide treatment altered NIH-3T3 cell proliferation within the parameters of the scratch assay. MANS peptide treatment also resulted in inhibited NIH-3T3 chemotaxis towards the chemoattractant platelet-derived growth factor-BB (PDGF-BB), with no effect observed with RNS treatment. Live cell imaging of PDGF-BB induced chemotaxis demonstrated that MANS peptide treatment resulted in weak chemotactic fidelity compared to RNS treated cells. MANS and RNS peptides did not affect PDGF-BB induced phosphorylation of MARCKS or phosphoinositide 3-kinase (PI3K) signaling, as measured by Akt phosphorylation. Further, no difference in cell migration was observed in NIH-3T3 fibroblasts that were transfected with MARCKS siRNAs with or without MANS peptide treatment. Genetic structure-function analysis revealed that MANS peptide-mediated attenuation of NIH-3T3 cell migration does not require the presence of the myristic acid moiety on the amino-terminus. Expression of either MANS or unmyristoylated MANS (UMANS) C-terminal EGFP fusion proteins resulted in similar levels of attenuated cell migration as observed with MANS peptide treatment. These data demonstrate that MARCKS regulates cell migration and suggests that MARCKS-mediated regulation of fibroblast migration involves the MARCKS amino-terminus. Further, this data demonstrates that MANS peptide treatment inhibits MARCKS function during fibroblast migration and that MANS mediated inhibition occurs independent of myristoylation. DA - 2013/6/19/ PY - 2013/6/19/ DO - 10.1371/journal.pone.0066512 VL - 8 IS - 6 SP - SN - 1932-6203 ER - TY - JOUR TI - Enzymatic processing of renewable glycerol into value-added glycerol carbonate AU - Cushing, Kerri A. AU - Peretti, Steven W. T2 - RSC ADVANCES AB - Increased production of biodiesel has led to excess glycerol production worldwide, which has resulted in a significant drop in glycerol prices. Glycerol carbonate is a multifunctional compound used as chemical intermediates, solvents, additives and monomers. In this study, the enzymatic synthesis of glycerol carbonate from glycerol and a dialkyl carbonate was investigated. Glycerol carbonate was formed when reacting glycerol with dimethyl carbonate, diethyl carbonate or dibutyl carbonate in the presence of Candida antarctica lipase B (Novozym 435), using tert-butanol as a solvent. Nearly 100% glycerol conversion was reached after 12 h, with glycerol carbonate being the primary product. The effects of reaction parameters including solvent choice and biocatalyst loading were also examined. The highest activity was found at restricted water conditions and when using tert-butanol as a solvent. DA - 2013/// PY - 2013/// DO - 10.1039/c3ra43811b VL - 3 IS - 40 SP - 18596-18604 SN - 2046-2069 ER - TY - JOUR TI - Engineering Cellular Photocomposite Materials Using Convective Assembly AU - Jenkins, Jessica S. AU - Flickinger, Michael C. AU - Velev, Orlin D. T2 - MATERIALS AB - Fabricating industrial-scale photoreactive composite materials containing living cells, requires a deposition strategy that unifies colloid science and cell biology. Convective assembly can rapidly deposit suspended particles, including whole cells and waterborne latex polymer particles into thin (<10 µm thick), organized films with engineered adhesion, composition, thickness, and particle packing. These highly ordered composites can stabilize the diverse functions of photosynthetic cells for use as biophotoabsorbers, as artificial leaves for hydrogen or oxygen evolution, carbon dioxide assimilation, and add self-cleaning capabilities for releasing or digesting surface contaminants. This paper reviews the non-biological convective assembly literature, with an emphasis on how the method can be modified to deposit living cells starting from a batch process to its current state as a continuous process capable of fabricating larger multi-layer biocomposite coatings from diverse particle suspensions. Further development of this method will help solve the challenges of engineering multi-layered cellular photocomposite materials with high reactivity, stability, and robustness by clarifying how process, substrate, and particle parameters affect coating microstructure. We also describe how these methods can be used to selectively immobilize photosynthetic cells to create biomimetic leaves and compare these biocomposite coatings to other cellular encapsulation systems. DA - 2013/5// PY - 2013/5// DO - 10.3390/ma6051803 VL - 6 IS - 5 SP - 1803-1825 SN - 1996-1944 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84881288013&partnerID=MN8TOARS KW - cellular photocomposites KW - continuous convective-sedimentation assembly KW - colloidal coatings KW - artificial leaves KW - biocomposite materials ER - TY - JOUR TI - Elastomeric microparticles for acoustic mediated bioseparations AU - Johnson, Leah M. AU - Gao, Lu AU - Shields, C. Wyatt AU - Smith, Margret AU - Efimenko, Kirill AU - Cushing, Kevin AU - Genzer, Jan AU - Lopez, Gabriel P. T2 - JOURNAL OF NANOBIOTECHNOLOGY AB - Acoustophoresis has been utilized successfully in applications including cell trapping, focusing, and purification. One current limitation of acoustophoresis for cell sorting is the reliance on the inherent physical properties of cells (e.g., compressibility, density) instead of selecting cells based upon biologically relevant surface-presenting antigens. Introducing an acoustophoretic cell sorting approach that allows biochemical specificity may overcome this limitation, thus advancing the value of acoustophoresis approaches for both the basic research and clinical fields.The results presented herein demonstrate the ability for negative acoustic contrast particles (NACPs) to specifically capture and transport positive acoustic contrast particles (PACPs) to the antinode of an ultrasound standing wave. Emulsification and post curing of pre-polymers, either polydimethylsiloxane (PDMS) or polyvinylmethylsiloxane (PVMS), within aqueous surfactant solution results in the formation of stable NACPs that focus onto pressure antinodes. We used either photochemical reactions with biotin-tetrafluorophenyl azide (biotin-TFPA) or end-functionalization of Pluronic F108 surfactant to biofunctionalize NACPs. These biotinylated NACPs bind specifically to streptavidin polystyrene microparticles (as cell surrogates) and transport them to the pressure antinode within an acoustofluidic chip.To the best of our knowledge, this is the first demonstration of using NACPs as carriers for transport of PACPs in an ultrasound standing wave. By using different silicones (i.e., PDMS, PVMS) and curing chemistries, we demonstrate versatility of silicone materials for NACPs and advance the understanding of useful approaches for preparing NACPs. This bioseparation scheme holds potential for applications requiring rapid, continuous separations such as sorting and analysis of cells and biomolecules. DA - 2013/6/28/ PY - 2013/6/28/ DO - 10.1186/1477-3155-11-22 VL - 11 SP - SN - 1477-3155 KW - Cell separation KW - Continuous cell sorting KW - Acoustofluidics KW - Particle synthesis KW - Ultrasound standing wave ER - TY - JOUR TI - Dynamics of nanoconfined water under pressure AU - Diallo, S. O. AU - Jazdzewska, M. AU - Palmer, J. C. AU - Mamontov, E. AU - Gubbins, K. E. AU - Sliwinska-Bartkowiak, M. T2 - PHYSICAL REVIEW E AB - We report a study of the effects of pressure on the diffusivity of water molecules confined in single- wall carbon nanotubes (SWNT) with average mean pore diameter of 16 Angstroms. The measurements were carried out using high-resolution neutron scattering, over the temperature range 220 < T < 260 K, and at two pressure conditions: ambient and elevated pressure. The high pressure data were collected at constant volume on cooling, with P varying from 1.92 kbar at temperature T = 260 K to 1.85 kbar at T = 220 K. Analysis of the observed dynamic structure factor S(Q, E) reveals the presence of two relaxation processes, a faster diffusion component (FC) associated with the motion of "caged" or restricted molecules, and a slower component arising from the free water molecules diffusing within the SWNT matrix. While the temperature dependence of the slow relaxation time exhibits a Vogel-Fulcher-Tammann law and is non-Arrhenius in nature, the faster component follows an Arrhenius exponential law at both pressure conditions. The application of pressure remarkably slows down the overall molecular dynamics, in agreement with previous observations, but most notably affects the slow relaxation. The faster relaxation shows marginal or no change with pressure within the experimental conditions. DA - 2013/8/26/ PY - 2013/8/26/ DO - 10.1103/physreve.88.022316 VL - 88 IS - 2 SP - SN - 2470-0053 ER - TY - CONF TI - Co3O4/carbon composite nanofibers for use as anode material in advanced lithium-ion batteries AU - Li, S. L. AU - Fu, K. AU - Xue, L. G. AU - Toprakci, O. AU - Li, Y. AU - Zhang, S. AU - Xu, G. J. AU - Lu, Y. AU - Zhang, Xiangwu AB - Co3O4/carbon composite nanofibers were prepared by a combination of electrospinning and carbonization methods using 10 - 30 nm and 30 - 50 nm Co3O4 nanoparticles, respectively, and their potential use as the anode material in rechargeable lithium-ion batteries was investigated. The composite Co3O4/carbon nanofiber electrode containing 30 - 50 nm Co3O4 nanoparticles showed large reversible capacities and good cycleability with charge capacities of 677 and 545 mAh g-1 at the second and twentieth cycles, respectively. In contrast, the composite Co3O4/carbon nanofiber electrode containing 10 - 30 nm Co3O4 nanoparticles showed fast capacity fading during cycling due to severe nanoparticle aggregation. Results suggested that the good electrochemical performance of Co3O4/carbon nanofiber electrode containing 30 - 50 nm Co3O4 nanoparticles was ascribed to the combination of the properties of both Co3O4 nanoparticles (large Li storage capability) and carbon nanofiber matrix (long cycle life), and therefore this electrode material could be potentially used in high-energy rechargeable lithium-ion batteries. C2 - 2013/// C3 - Nanotechnology for sustainable energy DA - 2013/// DO - 10.1021/bk-2013-1140.ch003 VL - 1140 SP - 55–66 UR - https://publons.com/publon/7178343/ ER - TY - JOUR TI - Chemical looping gasification of solid fuels using bimetallic oxygen carrier particles - Feasibility assessment and process simulations AU - He, Feng AU - Galinsky, Nathan AU - Li, Fanxing T2 - INTERNATIONAL JOURNAL OF HYDROGEN ENERGY AB - The chemical looping gasification (CLG) process utilizes an iron-based oxygen carrier to convert carbonaceous fuels into hydrogen and electricity while capturing CO2. Although the process has the potential to be efficient and environmentally friendly, the activity of the iron-based oxygen carrier is relatively low, especially for solid fuel conversion. In the present study, we propose to incorporate a secondary oxygen carrying metal oxide, i.e. CuO, to the iron-based oxygen carrier. Using the “oxygen-uncoupling” characteristics of CuO, gaseous oxygen is released at a high temperature to promote the conversion of both Fe2O3 and coal. Experiments carried out using a Thermal-Gravimetric Analyzer (TGA) indicate that a bimetallic oxygen carrier consisting of a small amount (5% by weight) of CuO is more effective for coal char conversion when compared to oxygen carrier without copper addition. ASPEN Plus® simulations and mathematical modeling of the process indicate that the incorporation of a small amount of copper leads to increased hydrogen yield and process efficiency. DA - 2013/6/27/ PY - 2013/6/27/ DO - 10.1016/j.ijhydene.2013.04.054 VL - 38 IS - 19 SP - 7839-7854 SN - 1879-3487 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84879093997&partnerID=MN8TOARS KW - Chemical looping KW - Gasification KW - Hydrogen KW - CO2 capture KW - Oxygen carrier ER - TY - JOUR TI - Cellulosic substrates for removal of pollutants from aqueous systems: A review. 3. spilled oil and emulsified organic liquids AU - Hubbe, M. A. AU - Rojas, O. J. AU - Fingas, M. AU - Gupta, B. S. T2 - BioResources AB - Water-insoluble oils, including crude petroleum and a wide variety of refined organic liquids, can cause major problems if spilled or leaked to aqueous environments. Potential environmental damage may be reduced if the spilled oil is promptly and efficiently removed from the water. This article reviews research that sheds light on the use of cellulose-based materials as sorbents to mitigate effects of oil spills. Encouraging results for oil sorption have been reported when using naturally hydrophobic cellulosic fibers such as unprocessed cotton, kapok, or milkweed seed hair. In addition, a wide assortment of cellulosic materials have been shown to be effective sorbents for hydrocarbon oils, especially in the absence of water, and their performance under water-wet conditions can be enhanced by various pretreatments that render them more hydrophobic. More research is needed on environmentally friendly systems to handle oil-contaminated sorbents after their use; promising approaches include their re-use after regeneration, anaerobic digestion, and incineration, among others. Research is also needed to further develop combined response systems in which biosorption is used along with other spill-response measures, including skimming, demulsification, biodegradation, and the use of booms to limit the spreading of oil slicks. DA - 2013/// PY - 2013/// DO - 10.15376/biores.8.2.3038-3097 VL - 8 IS - 2 SP - 3038-1179 ER - TY - JOUR TI - Catalytic graphitization and formation of macroporous-activated carbon nanofibers from salt-induced and H2S-treated polyacrylonitrile AU - Aykut, Yakup AU - Pourdeyhimi, Behnam AU - Khan, Saad A. T2 - JOURNAL OF MATERIALS SCIENCE DA - 2013/11// PY - 2013/11// DO - 10.1007/s10853-013-7463-x VL - 48 IS - 22 SP - 7783-7790 SN - 1573-4803 ER - TY - JOUR TI - Biological conversion of carbon dioxide and hydrogen into liquid fuels and industrial chemicals AU - Hawkins, Aaron S. AU - McTernan, Patrick M. AU - Lian, Hong AU - Kelly, Robert M. AU - Adams, Michael W. W. T2 - CURRENT OPINION IN BIOTECHNOLOGY AB - Non-photosynthetic routes for biological fixation of carbon dioxide into valuable industrial chemical precursors and fuels are moving from concept to reality. The development of 'electrofuel'-producing microorganisms leverages techniques in synthetic biology, genetic and metabolic engineering, as well as systems-level multi-omic analysis, directed evolution, and in silico modeling. Electrofuel processes are being developed for a range of microorganisms and energy sources (e.g. hydrogen, formate, electricity) to produce a variety of target molecules (e.g. alcohols, terpenes, alkenes). This review examines the current landscape of electrofuel projects with a focus on hydrogen-utilizing organisms covering the biochemistry of hydrogenases and carbonic anhydrases, kinetic and energetic analyses of the known carbon fixation pathways, and the state of genetic systems for current and prospective electrofuel-producing microorganisms. DA - 2013/6// PY - 2013/6// DO - 10.1016/j.copbio.2013.02.017 VL - 24 IS - 3 SP - 376-384 SN - 1879-0429 ER - TY - JOUR TI - Trophoblast differentiation of human embryonic stem cells AU - Tiruthani, Karthik AU - Sarkar, Prasenjit AU - Rao, Balaji T2 - BIOTECHNOLOGY JOURNAL AB - Abstract Molecular mechanisms regulating human trophoblast differentiation remain poorly understood due to difficulties in obtaining primary tissues from very early developmental stages in humans. Therefore, the use of human embryonic stem cells (hESCs) as a source for generating trophoblast tissues is of significant interest. Trophoblast‐like cells have been obtained through treatment of hESCs with bone morphogenetic protein (BMP) or inhibitors of activin/nodal/transforming growth factor‐β signaling, or through protocols involving formation of embryoid bodies (EBs); however, there is controversy over whether hESC‐derived cells are indeed analogous to true trophoblasts found in vivo. In this review, we provide an overview of previously described efforts to obtain trophoblasts from hESCs. We also discuss the merits and limitations of hESCs as a source of trophoblast derivatives. DA - 2013/4// PY - 2013/4// DO - 10.1002/biot.201200203 VL - 8 IS - 4 SP - 421-+ SN - 1860-7314 KW - Bone morphogenetic protein KW - CDX2 KW - ELF5 KW - hESC KW - Trophoblast ER - TY - JOUR TI - Structural and Kinetic Study of an Internal Substrate Binding Site in Dehaloperoxidase-Hemoglobin A from Amphitrite ornata AU - Zhao, Jing AU - Serrano, Vesna AU - Zhao, Junjie AU - Le, Peter AU - Franzen, Stefan T2 - BIOCHEMISTRY AB - X-ray crystal structures of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata soaked with substrate, 2,4,6-tribromophenol (2,4,6-TBP), in buffer solvent with added methanol (MeOH), 2-propanol (2-PrOH), and dimethyl sulfoxide (DMSO) reveal an internal substrate binding site deep in the distal pocket above the α-edge of the heme that is distinct from the previously determined internal inhibitor binding site. The peroxidase function of DHP A has most often been studied using 2,4,6-trichlorophenol (2,4,6-TCP) as a substrate analogue because of the low solubility of 2,4,6-TBP in an aqueous buffer solution. Previous studies at low substrate concentrations pointed to the binding of substrate 2,4,6-TCP at an external site near the exterior heme β- or δ-edge as observed in the class of heme peroxidases. Here we report that the turnover frequencies of both substrates 2,4,6-TCP and 2,4,6-TBP deviate from Michaelis–Menten kinetics at high concentrations. The turnover frequency reaches a maximum in the range of 1400–1700 μM, with a decrease in rate at higher concentrations that is both substrate- and solvent-dependent. The X-ray crystal structure is consistent with the presence of an internal active site above the heme α-edge, in which the substrate would be oxidized in two consecutive steps inside the enzyme, followed by attack by H2O via a water channel in the protein. The physiological role of the internal site may involve interactions with any of a number of aromatic toxins found in benthic ecosystems where A. ornata resides. DA - 2013/4/9/ PY - 2013/4/9/ DO - 10.1021/bi301307f VL - 52 IS - 14 SP - 2427-2439 SN - 0006-2960 ER - TY - JOUR TI - Strain-controlled diffraction of light from stretchable liquid metal micro-components AU - Mohammed, Mohammed G. AU - Dickey, Michael D. T2 - SENSORS AND ACTUATORS A-PHYSICAL AB - This paper elucidates and characterizes the origin of the spectrum of colors that appear on the surface of polydimethylsiloxane (PDMS) microchannels filled with liquid metal. The use of an oxygen plasma to seal the PDMS microchannels results in a thin oxide layer on the walls of the channels that buckles under compression to create diffractive corrugations. The liquid metal reflects the light from these corrugations. The thin layer of gallium oxide that forms on the metal improves the adhesion of the metal to the walls and thereby keeps it conformal with the corrugations during the buckling process. The conformal coating of metal makes the diffraction pattern more evident than if the metal was placed directly onto a pre-corrugated surface. This approach represents a simple method of fabricating soft diffractive elements with lithographically defined shapes that can be switched between a metallic and a colored state in response to compression; this feature may be used to sense compressive forces optically or for inherently aligned diffractive elements for optofluidics. DA - 2013/4/15/ PY - 2013/4/15/ DO - 10.1016/j.sna.2013.01.031 VL - 193 SP - 246-250 SN - 0924-4247 KW - Diffraction grating KW - Microfluidics KW - Liquid metal KW - Stretchable electronics KW - Buckles ER - TY - JOUR TI - Self-Healing Stretchable Wires for Reconfigurable Circuit Wiring and 3D Microfluidics AU - Palleau, Etienne AU - Reece, Stephen AU - Desai, Sharvil C. AU - Smith, Michael E. AU - Dickey, Michael D. T2 - ADVANCED MATERIALS AB - This article describes the fabrication of self-healing stretchable wires formed by embedding liquid metal wires in microchannels composed of self-healing polymer. These stretchable wires can be completely severed with scissors and rapidly self-heal both mechanically and electrically at ambient conditions. By cutting the channels strategically, the pieces can be re-assembled in a different order to form complex microfluidic networks in 2D or 3D space. DA - 2013/3/20/ PY - 2013/3/20/ DO - 10.1002/adma.201203921 VL - 25 IS - 11 SP - 1589-1592 SN - 1521-4095 KW - self-healing polymer KW - liquid metal KW - stretchable wire KW - reconfigurable electrical wiring KW - 3D microfluidics ER - TY - JOUR TI - Prevention of Ultraviolet (UV)-Induced Surface Damage and Cytotoxicity of Polyethersulfone Using Atomic Layer Deposition (ALD) Titanium Dioxide AU - Petrochenko, Peter E. AU - Scarel, Giovanna AU - Hyde, G. Kevin AU - Parsons, Gregory N. AU - Skoog, Shelby A. AU - Zhang, Qin AU - Goering, Peter L. AU - Narayan, Roger J. T2 - JOM AB - Nanostructured surfaces are finding use in several medical applications, including tissue scaffolds and wound dressings. These surfaces are frequently manufactured from biocompatible polymers that are susceptible to ultraviolet (UV) damage. Polyethersulfone (PES) is a biocompatible polymer that undergoes oxidation and degradation when exposed to ultraviolet (UV) light. A uniform TiO2 coating can protect PES during exposure to UV sources (e.g., germicidal lamps and sunlight). The goal of this study was to determine whether atomic layer deposition (ALD) can successfully be used to grow TiO2 onto PES, protect it from UV irradiation, and reduce macrophage in vitro cytotoxicity. TiO2 was ALD-coated onto PES at 21 nm thickness. Uncoated PES exposed to UV for 30 min visibly changed color, whereas TiO2-coated PES showed no color change, indicating limited degradation. Macrophages exposed to UV-treated PES for 48 h showed reduced cell viability (via MTT assay) to 18% of control. In contrast, the cell viability for UV-treated TiO2-coated PES was 90% of control. Non-UV treated PES showed no decrease in cell viability. The results indicate that ALD of TiO2 thin films is a useful technique to protect polymers from UV damage and to retain low cytotoxicity to macrophages and other types of cells that are involved in wound healing. TiO2- coated PES membranes also have potential use in direct methanol fuel cells and in wastewater treatment membranes. DA - 2013/4// PY - 2013/4// DO - 10.1007/s11837-013-0565-8 VL - 65 IS - 4 SP - 550-556 SN - 1543-1851 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000316078500014&KeyUID=WOS:000316078500014 ER - TY - JOUR TI - On the Surface Interactions of Proteins with Lignin AU - Salas, Carlos AU - Rojas, Orlando J. AU - Lucia, Lucian A. AU - Hubbe, Martin A. AU - Genzer, Jan T2 - ACS Applied Materials & Interfaces AB - Lignins are used often in formulations involving proteins but little is known about the surface interactions between these important biomacromolecules. In this work, we investigate the interactions at the solid–liquid interface of lignin with the two main proteins in soy, glycinin (11S) and β-conglycinin (7S). The extent of adsorption of 11S and 7S onto lignin films and the degree of hydration of the interfacial layers is quantified via Quartz crystal microgravimetry (QCM) and surface plasmon resonance (SPR). Solution ionic strength and protein denaturation (2-mercaptoethanol and urea) critically affect the adsorption process as protein molecules undergo conformational changes and their hydrophobic or hydrophilic amino acid residues interact with the surrounding medium. In general, the adsorption of the undenatured proteins onto lignin is more extensive compared to that of the denatured biomolecules and a large amount of water is coupled to the adsorbed molecules. The reduction in water contact angle after protein adsorption (by ∼40° and 35° for undenatured 11S and 7S, respectively) is explained by strong nonspecific interactions between soy proteins and lignin. DA - 2013/1/9/ PY - 2013/1/9/ DO - 10.1021/am3024788 VL - 5 IS - 1 SP - 199–206 SN - 1944-8244 1944-8252 UR - http://dx.doi.org/10.1021/am3024788 KW - adsorption KW - lignin KW - proteins KW - soy glycinin KW - beta-conglycinin KW - quartz crystal microbalance ER - TY - JOUR TI - Multifunctional and Durable Nanofiber-Fabric-Layered Composite for Protective Application AU - Shi, Quan AU - Vitchuli, Narendiran AU - Nowak, Joshua AU - Jiang, Shan AU - Caldwell, Jane M. AU - Breidt, Frederick AU - Bourham, Mohamed AU - Zhang, Xiangwu AU - McCord, Marian T2 - JOURNAL OF APPLIED POLYMER SCIENCE AB - A multifunctional and durable nanofiber-fabric-layered composite (NFLC) material was prepared by depositing electrospun Ag/PAN hybrid nanofibers onto a Nylon/cotton 50: 50 fabric substrate. The NFLCs showed excellent aerosol barrier efficiency and good air/moisture permeability. In addition, they showed excellent antibacterial efficiency by completely inhibiting the growth of both Gram-negative E. coli and Gram-positive S. aureus. The interfacial adhesion between the nanofiber layer and fabric substrate was significantly improved by atmospheric plasma pretreatment of the substrate. The resultant NFLCs showed excellent resistance to peeling, twisting, and flexing forces. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 DA - 2013/4/15/ PY - 2013/4/15/ DO - 10.1002/app.38465 VL - 128 IS - 2 SP - 1219-1226 SN - 1097-4628 UR - https://publons.com/publon/7178347/ KW - nanostructured polymers KW - textiles KW - biomedical applications ER - TY - JOUR TI - Iron Oxide with Facilitated O2- Transport for Facile Fuel Oxidation and CO2 Capture in a Chemical Looping Scheme AU - Galinsky, Nathan L. AU - Huang, Yan AU - Shafiefarhood, Arya AU - Li, Fanxing T2 - ACS SUSTAINABLE CHEMISTRY & ENGINEERING AB - The chemical looping strategy offers a potentially viable option for efficient carbonaceous fuel conversion with a reduced carbon footprint. In the chemical looping process, an oxygen carrier is reduced and oxidized in a cyclic manner to convert a carbonaceous fuel into separate streams of concentrated carbon dioxide and carbon-free products such as electricity and/or hydrogen. The reactivity and chemical and physical stability of the oxygen carrier are of pivotal importance to chemical looping processes. A typical oxygen carrier is composed of a multi-valence transition metal oxide supported on an “inert” support. Although the support does not get reduced or oxidized at any significant extent, numerous studies have indicated that certain supports such as TiO2 and Al2O3 can improve oxygen carrier stability and/or reactivity. This study reports the use of mixed ionic–electronic conductive support in iron-based oxygen carriers. By incorporating a perovskite-based mixed conductive support such as lanthanum strontium ferrite (LSF), the reactivity of the oxygen carrier is enhanced by 5–70 times when compared to oxygen carriers with conventional TiO2-, Al2O3-, or yttria-stabilized zirconia (YSZ) support. The mixed conductivity enhanced oxygen carrier also shows good stability and coke resistance. Characterization studies indicate that the enhanced oxygen carrier is composed of intermixed nanoscale (<100 nm) crystallites of iron oxide and support. The mixed conductive support enables facile O2– transport to and from the iron oxide nanocrystallites to participate in the surface redox reactions. The support also allows counter-current or concurrent diffusion of electrons or holes to maintain charge balance within the oxygen carrier. With iron oxide as the nanoscale oxygen source and mixed conductive support as the oxygen/electron conductor, the mixed conductivity enhanced oxygen carrier particle can be considered as an ensemble of nanoscale mixed conductive membrane reactors that possess excellent redox activity. DA - 2013/3// PY - 2013/3// DO - 10.1021/sc300177j VL - 1 IS - 3 SP - 364-373 SN - 2168-0485 KW - CO2 capture KW - Oxygen carrier KW - Chemical looping ER - TY - JOUR TI - Epitaxial PbxZr1-xTiO3 on GaN AU - Paisley, E. A. AU - Craft, H. S. AU - Losego, M. D. AU - Lu, H. AU - Gruverman, A. AU - Collazo, R. AU - Sitar, Z. AU - Maria, J. -P. T2 - JOURNAL OF APPLIED PHYSICS AB - Epitaxial integration of PbxZr1−xTiO3 (PZT) (111) with GaN (0002) presents the possibility of polarity coupling across a functional-oxide/nitride heteropolar interface. This work describes the synthesis and characterization of such thin film heterostructures by magnetron sputtering, with specific attention given to process optimization. Using x-ray diffraction and electrical characterization, the growth of epitaxial PZT (∼250 nm) on GaN and PZT on MgO/GaN stacks was verified. A two-stage growth process was developed for epitaxial PZT with a deposition temperature of 300 °C and an ex-situ anneal at 650 °C, which was effective in mitigating interfacial reactions and promoting phase-pure perovskite growth. Electrical analysis of interdigital capacitors revealed a nonlinear and hysteretic dielectric response consistent with ferroelectric PZT. Piezoresponse force microscopy (PFM) characterization shows clear evidence of ferroelectric switching, and PFM hysteresis loop analysis shows minimal evidence for direct polarity coupling, but suggests that band offsets which accompany the oxide-nitride heterostructures influence switching. DA - 2013/2/21/ PY - 2013/2/21/ DO - 10.1063/1.4792599 VL - 113 IS - 7 SP - SN - 1089-7550 ER - TY - JOUR TI - Enhanced Rate Capability by Employing Carbon Nanotube-Loaded Electrospun Si/C Composite Nanofibers As Binder-Free Anodes AU - Li, Ying AU - Xu, Guanjie AU - Xue, Leigang AU - Zhang, Shu AU - Yao, Yingfang AU - Lu, Yao AU - Toprakci, Ozan AU - Zhang, Xiangwu T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - Si/C and Si/carbon nanotube (CNT)/C composite nanofibers were prepared by electrospinning and carbonization. The carbon nanofiber matrix can accommodate the volume change of Si nanoparticles and provide continuous pathways for efficient charge transport along the fiber axis. CNTs can improve the electronic conductivity and electrochemical performance of the composite nanofiber anodes. Results showed that many different types of connections between CNTs, Si nanoparticles and carbon matrix were formed. At a high current density of 300 mA g−1, after 30 cycles, the capacity of Si/CNT/C composite nanofiber anode was 44.3% higher than the anode without CNT and the C-rate performance of Si/CNT/C composite nanofiber anode was also superior to that of Si/C anode. It is, therefore, demonstrated that Si/CNT/C nanofibers are promising anode material with large capacities, good cycling stability, and good rate capability. DA - 2013/// PY - 2013/// DO - 10.1149/2.031304jes VL - 160 IS - 3 SP - A528-A534 SN - 1945-7111 UR - https://publons.com/publon/674380/ ER - TY - JOUR TI - Durability of LDPE Nanocomposites with Clay, Silica, and Zinc Oxide-Part I: Mechanical Properties of the Nanocomposite Materials AU - Redhwi, Halim Hamid AU - Siddiqui, Mohammad Nahid AU - Andrady, Anthony L. AU - Hussain, Syed T2 - JOURNAL OF NANOMATERIALS AB - Three types of LDPE-based nanocomposites with montmorillonite clay, silica, and zinc oxide were prepared by melt blending the nanofiller with the resin. As a prelude to studying their durability, the extent of reinforcement of the LDPE matrix by the nanofillers was investigated using mechanical, thermal, and microscopic studies of the composites. No significant chemical modification of the polyethylene matrix was observed as a result of the processing of the composite compound. While reinforcement was obtained in all cases, the efficiency of reinforcement appears to be qualitatively influenced by surface functionalization, filler interactions, and the extent of dispersion of the filler in the matrix as well as the specific surface area of the nanoparticle fillers. DA - 2013/// PY - 2013/// DO - 10.1155/2013/654716 VL - 2013 SP - SN - 1687-4129 ER - TY - JOUR TI - Carbon-Coated Si Nanoparticles Dispersed in Carbon Nanotube Networks As Anode Material for Lithium-Ion Batteries AU - Xue, Leigang AU - Xu, Guanjie AU - Li, Ying AU - Li, Shuli AU - Fu, Kun AU - Shi, Quan AU - Zhang, Xiangwu T2 - ACS APPLIED MATERIALS & INTERFACES AB - Si has the highest theoretical capacity among all known anode materials, but it suffers from the dramatic volume change upon repeated lithiation and delithiation processes. To overcome the severe volume changes, Si nanoparticles were first coated with a polymer-driven carbon layer, and then dispersed in a CNT network. In this unique structure, the carbon layer can improve electric conductivity and buffer the severe volume change, whereas the tangled CNT network is expected to provide additional mechanical strength to maintain the integrity of electrodes, stabilize the electric conductive network for active Si, and eventually lead to better cycling performance. Electrochemical test result indicates the carbon-coated Si nanoparticles dispersed in CNT networks show capacity retention of 70% after 40 cycles, which is much better than the carbon-coated Si nanoparticles without CNTs. DA - 2013/1/9/ PY - 2013/1/9/ DO - 10.1021/am3027597 VL - 5 IS - 1 SP - 21-25 SN - 1944-8252 UR - https://publons.com/publon/1792840/ KW - lithium-ion battery KW - si-based anode KW - cycling stability KW - carbon coating KW - CNT networks ER - TY - JOUR TI - Avidity-mediated virus separation using a hyperthermophilic affinity ligand AU - Hussain, Mahmud AU - Lockney, Dustin AU - Wang, Ruqi AU - Gera, Nimish AU - Rao, Balaji M. T2 - BIOTECHNOLOGY PROGRESS AB - Abstract Immunoaffinity separation of large multivalent species such as viruses is limited by the stringent elution conditions necessary to overcome their strong and highly avid interaction with immobilized affinity ligands on the capture surface. Here we present an alternate strategy that harnesses the avidity effect to overcome this limitation. Red clover necrotic mosaic virus (RCNMV), a plant virus relevant to drug delivery applications, was chosen as a model target for this study. An RCNMV binding protein (RBP) with modest binding affinity ( K D ∼100 nM) was generated through mutagenesis of the Sso7d protein from Sulfolobus solfataricus and used as the affinity ligand. In our separation scheme, RCNMV is captured by a highly avid interaction with RBP immobilized on a nickel surface through a hexahistidine (6xHis) tag. Subsequently, disruption of the multivalent interaction and release of RCNMV is achieved by elution of RBP from the nickel surface. Finally, RCNMV is separated from RBP by exploiting the large difference in their molecular weights (∼8 MDa vs. ∼10 kDa). Our strategy not only eliminates the need for harsh elution conditions, but also bypasses chemical conjugation of the affinity ligand to the capture surface. Stable non‐antibody affinity ligands to a wide spectrum of targets can be generated through mutagenesis of Sso7d and other hyperthermophilic proteins. Therefore, our approach may be broadly relevant to cases where capture of large multivalent species from complex mixtures and subsequent release without the use of harsh elution conditions is necessary. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013 DA - 2013/// PY - 2013/// DO - 10.1002/btpr.1655 VL - 29 IS - 1 SP - 237-246 SN - 8756-7938 KW - avidity KW - affinity ligand KW - hyperthermophilic KW - multivalent ER - TY - JOUR TI - Affinity chromatographic purification of human immunoglobulin a from chinese hamster ovary cell culture supernatant AU - Liu, Zhuo AU - Gurgel, Patrick V. AU - Carbonell, Ruben G. T2 - BIOTECHNOLOGY PROGRESS AB - Abstract Hexamer peptide ligand HWRGWV, initially screened from a solid phase combinatorial peptide library for immunoglobulins G (IgG) purification, is shown to also have potential for immunoglobulin A (IgA) purification. The determined dissociation constants for hIgA on HWRGWV resins at three different peptide densities from 0.11 to 0.55 meq/g fall in the range of 10 −6 –10 −7 M, which are somewhat lower than those for hIgG. Although relatively low dynamic binding capacity (DBC) in the range of 9.2–16.8 mg IgA/mL resin at linear flow rates from 173 to 35 cm/h were obtained for IgA compared to IgG, the DBC value of HWRGWV for IgA is much greater than current commercially available affinity ligands. Although relatively lower binding affinity to secretory IgA compared to monomeric IgA was observed, the peptide ligand resins exhibit great potential for large‐scale purification of both human IgA and secretory IgA. Recoveries of 96.0% and 94.3%, and purities of 90.3% and 91.7% were achieved for human IgA and secretory IgA purification, respectively, from spiked Chinese hamster ovary cell culture supernatants without an extra afterwash step. Over 95% in purities were achieved for IgA and secretory IgA with an extra afterwash step; however, the recoveries would decrease at least 15% and 40% for IgA and secretory IgA, respectively. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013 DA - 2013/// PY - 2013/// DO - 10.1002/btpr.1652 VL - 29 IS - 1 SP - 91-98 SN - 1520-6033 KW - affinity chromatography KW - hexamer peptide KW - CHO KW - human immunoglobulin KW - secretory IgA ER - TY - JOUR TI - Two-dimensional colloidal networks induced by a uni-axial external field AU - Schmidle, Heiko AU - Jaeger, Sebastian AU - Hall, Carol K. AU - Velev, Orlin D. AU - Klapp, Sabine H. L. T2 - SOFT MATTER AB - Based on Monte Carlo and Molecular Dynamics computer simulations we investigate the aggregation patterns and dynamics of model colloidal mixtures consisting of particles with either one or two, oppositely oriented, induced dipole moments. The mixtures are confined to two spatial dimensions. Our model is inspired by recent optical-microscopy experiments involving polystyrene particles with (and without) gold patches. For a broad range of parameters, we find the model systems to self-assemble via a two-step scenario involving first percolation along the field, followed by a percolation transition in the transverse direction. The resulting two-dimensional networks are characterized by strongly hindered translational dynamics. DA - 2013/// PY - 2013/// DO - 10.1039/c2sm27210e VL - 9 IS - 8 SP - 2518-2524 SN - 1744-6848 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84875860529&partnerID=MN8TOARS ER - TY - JOUR TI - Specific Binding of Immunoglobulin G with Bioactive Short Peptides Supported on Antifouling Copolymer Layers for Detection in Quartz Crystal Microgravimetry and Surface Plasmon Resonance AU - Zhang, Yanxia AU - Islam, Nafisa AU - Carbonell, Ruben G. AU - Rojas, Orlando J. T2 - ANALYTICAL CHEMISTRY AB - A new peptide-based system supported on copolymer brushes grafted from gold sensors and with resistance to nonspecific adsorption is reported for selective binding of human immunoglobulin G (IgG). A random copolymer rich in primary amines, poly(2-aminoethyl methacrylate hydrochloride-co-2-hydroxyethyl methacrylate) (poly(AMA-co-HEMA)) was first grafted from initiator-coated gold substrates via activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP), followed by immobilization of acetylated-HWRGWVA peptide, which has specific binding affinity with IgG. The peptide ligands covalently linked to the soft copolymer layer were characterized by X-ray photoelectron spectroscopy (XPS), water contact angle, ellipsometry, and atomic force microscopy (AFM). The extent of binding, binding affinity, and selectivity for target IgG molecules as well as the capability to minimize nonspecific interactions with other proteins were examined by fluorescence imaging, surface plasmon resonance (SPR), and quartz crystal microgravimetry (QCM). The effect of copolymer molecular composition and analyte concentration was elucidated in order to design systems based on immobilized peptides for high signal-to-noise response and detection limits that meet the requirements for IgG biosensing in fluid matrixes. DA - 2013/1/15/ PY - 2013/1/15/ DO - 10.1021/ac302874s VL - 85 IS - 2 SP - 1106-1113 SN - 1520-6882 ER - TY - JOUR TI - Solvate Structures and Computational/Spectroscopic Characterization of Lithium Difluoro(oxalato)borate (LiDFOB) Electrolytes AU - Han, Sang-Don AU - Allen, Joshua L. AU - Jonsson, Erlendur AU - Johansson, Patrik AU - McOwen, Dennis W. AU - Boyle, Paul D. AU - Henderson, Wesley A. T2 - JOURNAL OF PHYSICAL CHEMISTRY C AB - Lithium difluoro(oxalato)borate (LiDFOB) is a relatively new salt designed for battery electrolyte usage. Limited information is currently available, however, regarding the ionic interactions of this salt (i.e., solvate formation) when it is dissolved in aprotic solvents. Vibrational spectroscopy is a particularly useful tool for identifying these interactions, but only if the vibrational bands can be correctly linked to specific forms of anion coordination. Single crystal structures of LiDFOB solvates have therefore been used to both explore the DFOB–...Li+ cation coordination interactions and serve as unambiguous models for the assignment of the Raman vibrational bands. The solvate crystal structures determined include (monoglyme)2:LiDFOB, (1,2-diethoxyethane)3/2:LiDFOB, (acetonitrile)3:LiDFOB, (acetonitrile)1:LiDFOB, (dimethyl carbonate)3/2:LiDFOB, (succinonitrile)1:LiDFOB, (adiponitrile)1:LiDFOB, (PMDETA)1:LiDFOB, (CRYPT-222)2/3:LiDFOB, and (propylene carbonate)1:LiDFOB. DFT calculations have been incorporated to provide additional insight into the origin (i.e., vibrational modes) of the Raman vibrational bands to aid in the interpretation of the experimental analysis. DA - 2013/3/21/ PY - 2013/3/21/ DO - 10.1021/jp309102c VL - 117 IS - 11 SP - 5521-5531 SN - 1932-7447 ER - TY - JOUR TI - Solution-Processed, Antimony-Doped Tin Oxide Colloid Films Enable High-Performance TiO2 Photoanodes for Water Splitting AU - Peng, Qing AU - Kalanyan, Berc AU - Hoertz, Paul G. AU - Miller, Andrew AU - Kim, Do Han AU - Hanson, Kenneth AU - Alibabaei, Leila AU - Liu, Jie AU - Meyer, Thomas J. AU - Parsons, Gregory N. AU - Glass, Jeffrey T. T2 - NANO LETTERS AB - Photoelectrochemical (PEC) water splitting and solar fuels hold great promise for harvesting solar energy. TiO2-based photoelectrodes for water splitting have been intensively investigated since 1972. However, solar-to-fuel conversion efficiencies of TiO2 photoelectrodes are still far lower than theoretical values. This is partially due to the dilemma of a short minority carrier diffusion length, and long optical penetration depth, as well as inefficient electron collection. We report here the synthesis of TiO2 PEC electrodes by coating solution-processed antimony-doped tin oxide nanoparticle films (nanoATO) on FTO glass with TiO2 through atomic layer deposition. The conductive, porous nanoATO film-supported TiO2 electrodes, yielded a highest photocurrent density of 0.58 mA/cm2 under AM 1.5G simulated sunlight of 100 mW/cm2. This is approximately 3× the maximum photocurrent density of planar TiO2 PEC electrodes on FTO glass. The enhancement is ascribed to the conductive interconnected porous nanoATO film, which decouples the dimensions for light absorption and charge carrier diffusion while maintaining efficient electron collection. Transient photocurrent measurements showed that nanoATO films reduce charge recombination by accelerating transport of photoelectrons through the less defined conductive porous nanoATO network. Owing to the large band gap, scalable solution processed porous nanoATO films are promising as a framework to replace other conductive scaffolds for PEC electrodes. DA - 2013/4// PY - 2013/4// DO - 10.1021/nl3045525 VL - 13 IS - 4 SP - 1481-1488 SN - 1530-6992 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000317549300020&KeyUID=WOS:000317549300020 KW - Photoelectrochemical KW - water splitting KW - antimony-doped tin oxide KW - TiO2 KW - core-shell ER - TY - JOUR TI - Self-assembly fronts in collision: impinging ordering organosilane layers AU - Efimenko, Kirill AU - Oezcam, Ali E. AU - Genzer, Jan AU - Fischer, Daniel A. AU - Phelan, Fredrick R., Jr. AU - Douglas, Jack F. T2 - SOFT MATTER AB - Colliding autocatalytic wave-fronts of self-assembling organosilane (OS) layers are generated through the controlled positioning of sources of the volatile OS material at the edges of a silica wafer and through adjustment of the container dimensions in which the wafer sources are placed. The concentration profiles and molecular orientation of the OS colliding wave-fronts are assessed by means of combinatorial near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. For systems involving self-assembly wave-fronts developing from the same OS precursor molecule, the shapes of interfacial region arising from front collision are centro-symmetrical and slowly ‘heal’ to form a uniform OS layer. In contrast, heterogeneous systems, involving OS molecules having different chemistries exhibit different rates of advance and highly non-symmetrical concentration profiles after front collision. We discuss the general nature of our OS colliding front data in terms of a mean field model of colliding reaction–diffusion fronts that generalizes a model introduced before for describing single OS front propagation. DA - 2013/// PY - 2013/// DO - 10.1039/c2sm27600c VL - 9 IS - 8 SP - 2493-2505 SN - 1744-6848 ER - TY - JOUR TI - Scaffold Diversification Enhances Effectiveness of a Super library of Hyperthermophilic Proteins AU - Hussain, Mahmud AU - Gera, Nimish AU - Hill, Andrew B. AU - Rao, Balaji M. T2 - ACS SYNTHETIC BIOLOGY AB - The use of binding proteins from non-immunoglobulin scaffolds has become increasingly common in biotechnology and medicine. Typically, binders are isolated from a combinatorial library generated by mutating a single scaffold protein. In contrast, here we generated a “superlibrary” or “library-of-libraries” of 4 × 108 protein variants by mutagenesis of seven different hyperthermophilic proteins; six of the seven proteins have not been used as scaffolds prior to this study. Binding proteins for five different model targets were successfully isolated from this library. Binders obtained were derived from five out of the seven scaffolds. Strikingly, binders from this modestly sized superlibrary have affinities comparable or higher than those obtained from a library with 1000-fold higher sequence diversity but derived from a single stable scaffold. Thus scaffold diversification, i.e., randomization of multiple different scaffolds, is a powerful alternate strategy for combinatorial library construction. DA - 2013/1// PY - 2013/1// DO - 10.1021/sb300029m VL - 2 IS - 1 SP - 6-13 SN - 2161-5063 KW - hyperthermophilic protein scaffolds KW - yeast surface display KW - protein engineering KW - alternate scaffold KW - mRNA display ER - TY - JOUR TI - Protein-assisted 2D assembly of gold nanoparticles on a polysaccharide surface AU - Taajamaa, Laura AU - Rojas, Orlando J. AU - Laine, Janne AU - Yliniemi, Kirsi AU - Kontturi, Eero T2 - CHEMICAL COMMUNICATIONS AB - Site-specific assembly of gold nanoparticles on a polysaccharide surface was accomplished via a straightforward method exploiting interfacial polymer blends, selective protein adsorption and electrostatic interaction. The method could be useful in further applications due to the universal nature of the utilized phenomena. DA - 2013/// PY - 2013/// DO - 10.1039/c2cc37288f VL - 49 IS - 13 SP - 1318-1320 SN - 1364-548X ER - TY - JOUR TI - Preferential Adsorption and Activity of Monocomponent Cellulases on Lignocellulose Thin Films with Varying Lignin Content AU - Martin-Sampedro, Raquel AU - Rahikainen, Jenni L. AU - Johansson, Leena-Sisko AU - Marjamaa, Kaisa AU - Laine, Janne AU - Kruus, Kristiina AU - Rojas, Orlando J. T2 - BIOMACROMOLECULES AB - Understanding the enzymatic hydrolysis of cellulose and the influence of lignin in the process are critical for viable production of fuels and chemicals from lignocellulosic biomass. The interactions of monocomponent cellulases with cellulose and lignin substrates were investigated by using thin films supported on quartz crystal microgravimetry (QCM) resonators. Trichoderma reesei exoglucanase (CBH-I) and endoglucanase (EG-I) bound strongly to both cellulose and lignin but EG-I exhibited a distinctive higher affinity with lignin, causing a more extensive inhibition of the cellulolytic reactions. CBH-I was found to penetrate into the bulk of the cellulose substrate increasing the extent of hydrolysis and film deconstruction. In the absence of a cellulose binding domain (CBD) and a linker, the CBH-I core adsorbed slowly and was not able to penetrate into the film. Conversely to CBH-I, EG-I exhibited activity only on the surface of the lignocellulose substrate even when containing a CBD and a linker. Interestingly, EG-I displayed a clearly different interaction profile as a function of contact time registered by QCM. DA - 2013/4// PY - 2013/4// DO - 10.1021/bm400230s VL - 14 IS - 4 SP - 1231-1239 SN - 1526-4602 ER - TY - JOUR TI - Mid-infrared surface plasmon resonance in zinc oxide semiconductor thin films AU - Sachet, E. AU - Losego, M. D. AU - Guske, J. AU - Franzen, S. AU - Maria, J. P. T2 - Applied Physics Letters DA - 2013/// PY - 2013/// VL - 102 IS - 5 ER - TY - JOUR TI - Isotropic-polar phase transitions in an amphiphilic fluid: Density functional theory versus computer simulations AU - Giura, Stefano AU - Markus, Bence G. AU - Klapp, Sabine H. L. AU - Schoen, Martin T2 - PHYSICAL REVIEW E AB - We investigate the critical line separating isotropic from polar phases in an amphiphilic bulk fluid by means of density functional theory (DFT) and Monte Carlo (MC) simulations in the isothermal-isobaric ensemble. The intermolecular interactions are described by a Lennard-Jones potential in which the attractive contribution is modified by an orientation-dependent function. The latter consists of two terms: The first one has the orientation dependence of a classical three-dimensional Heisenberg interaction, whereas, the second one has the orientation dependence of a classical dipole-dipole interaction. However, both contributions are short range. Employing DFT together with a modified mean-field (MMF) approximation for the orientation-dependent pair correlation function, we derive an analytical expression for the critical line separating isotropic from polar liquidlike phases. In parallel MC simulations, we locate the line of critical points through an analysis of Binder's second-order cumulant of the polar-order parameter. Comparison with DFT shows that the dipolelike contribution is irrelevant for the isotropic-polar phase transition. As far as the Heisenberg contribution is concerned, the MC data are in semiquantitative agreement with the DFT predictions for sufficiently strong coupling between molecular orientations. For weaker coupling, the variation in the ratio of critical density and temperature ρ(c)/T(c) with the Heisenberg coupling constant ε(H) is underestimated by the MMF treatment. The MC results suggest that this is because ρ(c) increases with decreasing ε(H) such that the assumption on which the MMF approach rests becomes less applicable in the weaker-coupling limit. DA - 2013/1/31/ PY - 2013/1/31/ DO - 10.1103/physreve.87.012313 VL - 87 IS - 1 SP - SN - 1550-2376 ER - TY - JOUR TI - Computer Simulation of Template Polymerization Using a Controlled Reaction Scheme AU - Datta, Preeta AU - Genzer, Jan T2 - MACROMOLECULES AB - We employ a Monte Carlo simulation scheme based on the bond fluctuation model to simulate template polymerization via controlled polymerization scheme involving copolymerization of free monomers (A) and monomers bound to a template (B) that consists of linear or ring-like substrates with equidistant sites occupied by bound B monomers. Both A and B are chemically identical; i.e., there is no interaction potential acting between A and B. A new macromolecule is initiated in bulk by activation of an initiator; any monomer that is within the reaction distance (nearest neighbors) of the initiator can be incorporated into the chain. As the macromolecule grows, it adds either bulk (i.e., A) or template-bound monomers (i.e., B) to its chain. The living nature of the polymers is assured by eliminating any termination or chain transfer. We analyze the effect of the number and spacing of the B bound monomers on the substrate on the chemical composition and monomer distribution in the resultant A–B random copolymer. Our results reveal that the likelihood of B being incorporated in the A–B copolymer increases with increasing the number and density of the B monomers on the template substrate; the maximum sequence length of “polymerized” bound B monomers increases with increasing the number of bound B monomers present in a single substrate. Long consecutive sequences of B bound monomers in the A–B copolymer are formed when the B bound monomers are immobilized in space in high densities. DA - 2013/3/26/ PY - 2013/3/26/ DO - 10.1021/ma3025915 VL - 46 IS - 6 SP - 2474-2484 SN - 1520-5835 ER - TY - JOUR TI - Characterizing polymer macrostructures by identifying and locating microstructures along their chains with the kerr effect AU - Hardrict, S. N. AU - Gurarslan, R. AU - Galvin, C. J. AU - Gracz, H. AU - Roy, D. AU - Sumerlin, B. S. AU - Genzer, J. AU - Tonelli, A. E. T2 - JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS AB - Abstract In this brief report, we demonstrate that Kerr effect measurements, which determine the excess birefringence contributed by polymer solutes in dilute solutions observed under a strong electric field, are highly sensitive to and capable of determining their microstructures, as well as their locations along the macromolecular backbone. Specifically, using atactic triblock copolymers with the same overall composition of styrene (S) and p ‐bromostyrene ( p BrS) units, but with two different block arrangements, that is, p BrS 90 ‐ b ‐S 120 ‐ b ‐ p BrS 90 (I) and S 60 ‐ b ‐ p BrS 180 ‐ b ‐S 60 (II), which are indistinguishable by NMR, we detected a dramatic difference in their molar Kerr constants ( m K ), in agreement with those previously estimated. Although similar in magnitude, their Kerr constants differ in sign, with m K (II) positive and m K (I) negative. In addition, S/ p BrS random and gradient copolymers synthesized by reversible addition‐fragmentation chain‐transfer (RAFT) polymerization exhibit a heretofore unexpected enhanced enchainment of racemic ( r ) p BrS‐ p BrS diads. Comparison of their observed and calculated m K s suggests that the gradient S/ p BrS copolymers possess an unanticipated additional gradient in stereosequence that parallels their comonomer gradient, that is, as the concentration of p Brs units decreases from one end of the copolymer chain to the other, so does the content of r diads. This conclusion could only be reached by comparison of observed and calculated Kerr effects, which access the global properties of macromolecules, and not NMR, which is only sensitive to local polymer structural environments, but not to their locations on the copolymer chains. Molar Kerr constants are characteristic of entire polymer chains and are highly sensitive to their constituent microstructures and their distribution along the chain. They may be used to both identify constituent microstructures and locate them along the polymer chain, thereby enabling, for the first time, characterization of their complete macrostructures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 DA - 2013/5/1/ PY - 2013/5/1/ DO - 10.1002/polb.23248 VL - 51 IS - 9 SP - 735-741 SN - 0887-6266 KW - microstructure KW - solution properties KW - structure-property relations KW - thin films ER - TY - JOUR TI - Catalytic efficiency of dehaloperoxidase A is controlled by electrostatics - application of the vibrational Stark effect to understand enzyme kinetics AU - Schkolnik, Gal AU - Utesch, Tillmann AU - Zhao, Junjie AU - Jiang, Shu AU - Thompson, Matthew K. AU - Mroginski, Maria-Andrea AU - Hildebrandt, Peter AU - Franzen, Stefan T2 - BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS AB - The vibrational Stark effect is gaining popularity as a method for probing electric fields in proteins. In this work, we employ it to explain the effect of single charge mutations in dehaloperoxidase-hemoglobin A (DHP A) on the kinetics of the enzyme. In a previous communication published in this journal (BBRC 2012, 420, 733-737) it has been shown that an increase in the overall negative charge of DHP A through mutation causes a decrease in its catalytic efficiency. Here, by labeling the protein with 4-mercaptobenzonitrile (MBN), a Stark probe molecule, we provide further evidence that the diffusion control of the catalytic process arises from the electrostatic repulsion between the enzyme and the negatively charged substrate. The linear correlation observed between the nitrile stretching frequency of the protein-bound MBN and the catalytic efficiency of the single-site mutants of the enzyme indicates that electrostatic interactions play a dominant role in determining the catalytic efficiency of DHP A. DA - 2013/1/18/ PY - 2013/1/18/ DO - 10.1016/j.bbrc.2012.12.047 VL - 430 IS - 3 SP - 1011-1015 SN - 1090-2104 KW - Vibrational Stark effect KW - Hemoglobin KW - 4-mercaptobenzonitrile KW - Enzyme kinetics KW - Electric field ER - TY - JOUR TI - Affinity chromatographic purification of human immunoglobulin M from human B lymphocyte cell culture supernatant AU - Liu, Zhuo AU - Gurgel, Patrick V. AU - Carbonell, Ruben G. T2 - BIOCHEMICAL ENGINEERING JOURNAL AB - Abstract Compared to immunoglobulin G purification with extensively studied affinity ligands such as protein A and protein G, little work has been done on affinity chromatographic purification of immunoglobulin M. Hexamer peptide ligand HWRGWV, previously shown to bind specifically to the Fc fragment of IgG, also demonstrated potential for IgM purification. This study presents further characterization and investigation of this ligand for its potential for purification of IgM. Different running conditions were employed in order to improve the recovery and purity of IgM. The final recovery and purity of the antibody is feedstock dependent, but can reach levels of both recovery and purity as high as 95%. The dependence of the recovery and purity on total loading amount and initial IgM concentration were investigated and discussed. Although relatively low dynamic binding capacities (DBC) in the range of 4.6–13.1 mg IgM/mL resin at linear flow rates from 173 to 35 cm/h were obtained for IgM compared to IgG because of the large molecular weight of IgM, the DBC value of HWRGWV for IgM is much greater than protein-based IgM affinity ligands found in the literature and is competitive with current commercially available affinity ligands, such as KAPTIVE-M, CaptureSelect IgM and Ultralink Immobilized Mannan Binding Protein. DA - 2013/1/15/ PY - 2013/1/15/ DO - 10.1016/j.bej.2012.10.003 VL - 70 SP - 63-70 SN - 1873-295X KW - Affinity chromatography KW - Hexamer peptide KW - Human immunoglobulin KW - IgM KW - Dynamic binding capacity KW - Elution additive ER - TY - JOUR TI - Ultrastretchable Fibers with Metallic Conductivity Using a Liquid Metal Alloy Core AU - Zhu, Shu AU - So, Ju-Hee AU - Mays, Robin AU - Desai, Sharvil AU - Barnes, William R. AU - Pourdeyhimi, Behnam AU - Dickey, Michael D. T2 - ADVANCED FUNCTIONAL MATERIALS AB - Abstract The fabrication and characterization of fibers that are ultrastretchable and have metallic electrical conductivity are described. The fibers consist of a liquid metal alloy, eutectic gallium indium (EGaIn), injected into the core of stretchable hollow fibers composed of a triblock copolymer, poly[styrene‐ b ‐(ethylene‐ co ‐butylene)‐ b ‐styrene] (SEBS) resin. The hollow fibers are easy to mass‐produce with controlled size using commercially available melt processing methods. The fibers are similar to conventional metallic wires, but can be stretched orders of magnitude further while retaining electrical conductivity. Mechanical measurements with and without the liquid metal inside the fibers show the liquid core has a negligible impact on the mechanical properties of the fibers, which is in contrast to most conductive composite fibers. The fibers also maintain the same tactile properties with and without the metal. Electrical measurements show that the fibers increase resistance as the fiber elongates and the cross sectional area narrows. Fibers with larger diameters change from a triangular to a more circular cross‐section during stretching, which has the appeal of lowering the resistance below that predicted by theory. To demonstrate their utility, the ultrastretchable fibers are used as stretchable wires for earphones and for a battery charger and perform as well as their conventional parts. DA - 2013/5/13/ PY - 2013/5/13/ DO - 10.1002/adfm.201202405 VL - 23 IS - 18 SP - 2308-2314 SN - 1616-3028 KW - stretchable electronics KW - eutectic gallium indium KW - conductive fibers ER - TY - JOUR TI - Transformation of lignocellulosic biomass during torrefaction AU - Park, Junyeong AU - Meng, Jiajia AU - Lim, Kwang Hun AU - Rojas, Orlando J. AU - Park, Sunkyu T2 - JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS AB - In this study, the effect of torrefaction on the chemical and structural transformation of lignocellulosic biomass was investigated using complementary analytical tools. It was observed that the acid-insoluble fraction was increased from approximately 30 to 38% and the methoxyl content was decreased to about half after torrefaction at 330 °C for 2.5 min. These results highlight the formation of condensed structures along with lignin transformation via demethoxylation. Solid-state NMR spectroscopy indicated that upon torrefaction the aromaticity increased from about 36 to 60%. For the sample torrefied at 330 °C, the non-protonated aromatic carbon fraction was found to be about 60% of total aromatic carbons, indicating the formation of large aromatic clusters. The complementary analyses used in this study are proposed as a suitable approach for the elucidation of chemical and structural transformation of biomass during thermal treatment. DA - 2013/3// PY - 2013/3// DO - 10.1016/j.jaap.2012.12.024 VL - 100 SP - 199-206 SN - 0165-2370 KW - Lignocellulosic biomass KW - Torrefaction KW - Solid-state NMR KW - Non-protonated aromatic carbon KW - Methoxyl content analysis ER - TY - JOUR TI - Thiol-containing polymeric embedding materials for nanoskiving AU - Mays, Robin L. AU - Pourhossein, Parisa AU - Savithri, Dhanalekshmi AU - Genzer, Jan AU - Chiechi, Ryan C. AU - Dickey, Michael D. T2 - JOURNAL OF MATERIALS CHEMISTRY C AB - This paper describes the characterization of new embedding resins for nanoskiving (ultramicrotomy) that contain thiols. Nanoskiving is a technique to produce nanoscale structures using an ultramicrotome to section thin films of materials (e.g., gold) embedded in polymer. Epoxies are used typically as embedding resins for microtomy. Epoxies, however, do not adhere well to gold or other smooth metallic structures that are used commonly for nanoskiving. Thiol–ene and thiol–epoxy polymers provide improved adhesion to gold due to the thiol functional group. In addition, the thiol–ene polymers can be prepared within minutes using photopolymerization, which allows for rapid prototyping. Two commercial thiol-containing adhesives were evaluated as resins in addition to several formulations of commercially available monomers. The important physical and mechanical properties for microtomy of these unconventional embedding resins were characterized and the properties were compared to commercial epoxy resins. Gold nanowires were fabricated using nanoskiving of gold films embedded in these unconventional resins. These studies show that a 3 : 4 mixture of thiol (pentaerythritol tetra(3-mercaptopropionate)) and ene (triallyl-1,3,5-triazine-2,4,6-trione) works very well as a resin for nanoskiving and provides improved adhesion and reduced preparation time relative to epoxies. DA - 2013/// PY - 2013/// DO - 10.1039/c2tc00030j VL - 1 IS - 1 SP - 121-130 SN - 2050-7534 ER - TY - JOUR TI - Thermal transport: Breaking through barriers AU - Losego, M. D. AU - Cahill, D. G. T2 - Nature Materials DA - 2013/// PY - 2013/// VL - 12 IS - 5 SP - 382-384 ER - TY - JOUR TI - Structures and properties of SnO2 nanofibers derived from two different polymer intermediates AU - Xia, Xin AU - Li, Shuli AU - Wang, Xin AU - Liu, Junxiong AU - Wei, Qufu AU - Zhang, Xiangwu T2 - JOURNAL OF MATERIALS SCIENCE DA - 2013/5// PY - 2013/5// DO - 10.1007/s10853-012-7122-7 VL - 48 IS - 9 SP - 3378-3385 SN - 1573-4803 UR - https://publons.com/publon/7178341/ ER - TY - JOUR TI - Stabilization of [Ru(bpy)(2)(4,4 '-(PO3H2)bpy)](2+) on Mesoporous TiO2 with Atomic Layer Deposition of Al2O3 AU - Hanson, Kenneth AU - Losego, Mark D. AU - Kalanyan, Berc AU - Ashford, Dennis L. AU - Parsons, Gregory N. AU - Meyer, Thomas J. T2 - CHEMISTRY OF MATERIALS AB - ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTStabilization of [Ru(bpy)2(4,4′-(PO3H2)bpy)]2+ on Mesoporous TiO2 with Atomic Layer Deposition of Al2O3Kenneth Hanson†, Mark D. Losego‡, Berç Kalanyan‡, Dennis L. Ashford†, Gregory N. Parsons*‡, and Thomas J. Meyer*†View Author Information† Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States‡ Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States*E-mail: [email protected] (G.N.P.); [email protected] (T.J.M.).Cite this: Chem. Mater. 2013, 25, 1, 3–5Publication Date (Web):December 7, 2012Publication History Received1 October 2012Revised6 December 2012Published online18 December 2012Published inissue 8 January 2013https://doi.org/10.1021/cm303172wCopyright © 2012 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views2519Altmetric-Citations84LEARN 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. 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Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (567 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Atomic layer deposition,Chromophores,Desorption,Kinetic parameters,Oxides Get e-Alerts DA - 2013/1/8/ PY - 2013/1/8/ DO - 10.1021/cm303172w VL - 25 IS - 1 SP - 3-5 SN - 0897-4756 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000313303400002&KeyUID=WOS:000313303400002 KW - stability KW - dye-sensitized KW - atomic layer deposition (ALD) KW - TiO2 KW - Al2O3 ER - TY - JOUR TI - Progress in Computer Simulation of Bulk, Confined, and Surface-initiated Polymerizations AU - Bain, Erich D. AU - Turgman-Cohen, Salomon AU - Genzer, Jan T2 - MACROMOLECULAR THEORY AND SIMULATIONS AB - Abstract In this article we provide a brief summary of computational techniques applied to investigate polymerization reactions in general, with a focus on systems under confinement and initiated from surfaces. We concentrate on two major classes of techniques, i.e., stochastic methods and molecular modeling. We describe the major principles of the two classes of methodologies and point out their strengths and weaknesses. We review a variety of studies from the literature and conclude with an outlook of these two classes of computer simulation approaches as they are applied to “grafting from” polymerizations. magnified image DA - 2013/1// PY - 2013/1// DO - 10.1002/mats.201200030 VL - 22 IS - 1 SP - 8-30 SN - 1521-3919 KW - computer simulation KW - Gillespie KW - grafting from KW - polymerization KW - stochastic ER - TY - JOUR TI - Physicochemical properties of binary ionic liquid-aprotic solvent electrolyte mixtures AU - Fox, E. T. AU - Paillard, E. AU - Borodin, O. AU - Henderson, W. A. T2 - Journal of Physical Chemistry. C DA - 2013/// PY - 2013/// VL - 117 IS - 1 SP - 78-84 ER - TY - JOUR TI - Monte-carlo simulations of the order-disorder transition depression in ABA triblock copolymers with a short terminal block AU - Woloszczuk, S. AU - Banaszak, M. AU - Spontak, R. J. T2 - JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS AB - Abstract Although most ABA triblock copolymers are molecularly symmetric (i.e., the terminal blocks possess the same mass), molecularly asymmetric A1BA2 triblock copolymers are of greater fundamental interest in that they can be used to explore the transition from diblock to triblock copolymer in systematic fashion. In this study, we use a lattice Monte Carlo method known as the cooperative motion algorithm to simulate molten ABA triblock copolymers possessing a short terminal block to explore the effect of molecular asymmetry on the copolymer order–disorder transition (ODT). Reduced ODT temperatures, discerned by simultaneously analyzing several features of the simulation results, are found to compare favorably with experimental data. Of particular interest here is the initial depression in the ODT temperature for A1BA2 copolymers possessing a relatively short terminal (A2) block. This signature feature is successfully captured by the simulations and is found to be strongly dependent on composition, but weakly dependent on copolymer chain length. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 DA - 2013/3/1/ PY - 2013/3/1/ DO - 10.1002/polb.23215 VL - 51 IS - 5 SP - 343-348 SN - 1099-0488 KW - diblock copolymers KW - phase separation KW - molecular modeling KW - Monte Carlo simulation ER - TY - JOUR TI - Midblock-sulfonated triblock ionomers derived from a long-chain poly[styrene-b-butadiene-b-styrene] triblock copolymer AU - Vargantwar, Pruthesh H. AU - Brannock, Molly C. AU - Tauer, Klaus AU - Spontak, Richard J. T2 - JOURNAL OF MATERIALS CHEMISTRY A AB - Selective sulfonation of a poly[styrene-b-butadiene-b-styrene] (SBS) triblock copolymer has been performed with a sulfur trioxide–dioxane (SO3–dioxane) complex to generate midblock-sulfonated triblock ionomers possessing varying degrees of sulfonation (DOS). Products of the sulfonation reaction have been characterized by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopies to ensure sulfonation only involves the B midblocks. Due to this targeted sulfonation, the lower glass transition temperature (Tg) disappears completely in all the ionomers examined, indicating that the formation of ionic aggregates restricts the mobility of the B midblocks. Such aggregates hinder microphase separation and promote a diffuse interface, as established by progressive broadening of the upper Tg with increasing DOS. Additional evidence of diffuse interfaces and matrix densification is provided by small-angle X-ray scattering, which reveals a concurrent size reduction in microdomain spacing with increasing DOS. A sulfonation-induced order–order morphological transition from cylinders to lamellae is likewise observed. Due to the retention of microphase-separated glassy microdomains that serve as physical crosslinks, these triblock ionomers are capable of absorbing remarkably high solvent levels and forming highly swollen gel networks in polar media, thereby making them suitable for use in hygiene and healthcare applications, as well as in devices requiring ion transport. DA - 2013/// PY - 2013/// DO - 10.1039/c2ta00022a VL - 1 IS - 10 SP - 3430-3439 SN - 2050-7496 ER - TY - JOUR TI - Mechanical deconstruction of lignocellulose cell walls and their enzymatic saccharification AU - Hoeger, Ingrid C. AU - Nair, Sandeep S. AU - Ragauskas, Arthur J. AU - Deng, Yulin AU - Rojas, Orlando J. AU - Zhu, J. Y. T2 - CELLULOSE DA - 2013/4// PY - 2013/4// DO - 10.1007/s10570-013-9867-9 VL - 20 IS - 2 SP - 807-818 SN - 1572-882X KW - Cell wall deconstruction KW - Enzymatic hydrolysis KW - Saccharification KW - Lignocelluloses KW - Size reduction KW - Grinding KW - Nanocellulose KW - Nanofibers KW - Nanofibrils KW - Lignocellulose nanofibrils KW - Biofuel ER - TY - JOUR TI - Laccase-Mediated Coupling of Nonpolar Chains for the Hydrophobization of Lignocellulose AU - Garcia-Ubasart, Jordi AU - Vidal, Teresa AU - Torres, Antonio L. AU - Rojas, Orlando J. T2 - BIOMACROMOLECULES AB - We investigate the use of laccase enzymes to couple short nonpolar chains containing aromatic groups onto flax fibers and nanofibrillated cellulose (NFC) with different lignin contents. Trametes villosa, Pycnoporus cinnabarinus, and Myceliophthora thermophila were used to facilitate surface coupling and to produce materials with different levels of hydrophobicity. Heat treatment of fiber webs after lacccase-mediated coupling markedly increased the resistance to water absorption. The highest hydrophobization levels of flax fibers was achieved by coupling dodecyl 3,4,5-trihydroxybenzoate (HB-C12), which yielded water contact angles (WCAs) of 80–96 degrees and water absorption times (drop tests) of ca. 73 min. The results from apparent aromatic content and FTIR analyses confirmed the laccase-mediated coupling of HB-C12 onto the cellulose fibers. Ultrathin films of NFC were also used as substrates for enzyme-mediated hydrophobization with HB-C12. In these cases, WCAs in the range of 87–104 degrees were achieved, depending on the conditions. Quartz crystal microgravimetry (QCM) was used to study the dynamics and the extent of the coupling process onto cellulose. The results help to better understand the mechanisms involved in laccase-mediated hydrophobization and provide a proof of a biotechnological platform for the development of value-added fiber products. DA - 2013/5// PY - 2013/5// DO - 10.1021/bm400291s VL - 14 IS - 5 SP - 1637-1644 SN - 1525-7797 ER - TY - JOUR TI - Generating Better Medicines for Cancer AU - Dunn, Stuart S. AU - Byrne, James D. AU - Perry, Jillian L. AU - Chen, Kai AU - DeSimone, Joseph M. T2 - ACS MACRO LETTERS AB - The complexity of tumor biology warrants tailored drug delivery for overcoming the major challenges faced by cancer therapies. The versatility of the PRINT® (Particle Replication In Non-wetting Templates) process has enabled the preparation of shape- and size-specific particles with a wide range of chemical compositions and therapeutic cargos. Different particle matrices and drugs may be combined in a plug-and-play approach, such that physico-chemical characteristics of delivery vectors may be optimized for biocompatibility, cargo stability and release, circulation half-life, and efficacy. Thus, the engineering of particles for cancer therapy with specific biophysical behaviors and cellular responses has been demonstrated via the PRINT process. DA - 2013/5// PY - 2013/5// DO - 10.1021/mz400116a VL - 2 IS - 5 SP - 393-397 SN - 2161-1653 ER - TY - JOUR TI - Exploiting microbial hyperthermophilicity to produce an industrial chemical, using hydrogen and carbon dioxide AU - Keller, Matthew W. AU - Schut, Gerrit J. AU - Lipscomb, Gina L. AU - Menon, Angeli L. AU - Iwuchukwu, Ifeyinwa J. AU - Leuko, Therese T. AU - Thorgersen, Michael P. AU - Nixon, William J. AU - Hawkins, Aaron S. AU - Kelly, Robert M. AU - Adams, Michael W. W. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Microorganisms can be engineered to produce useful products, including chemicals and fuels from sugars derived from renewable feedstocks, such as plant biomass. An alternative method is to use low potential reducing power from nonbiomass sources, such as hydrogen gas or electricity, to reduce carbon dioxide directly into products. This approach circumvents the overall low efficiency of photosynthesis and the production of sugar intermediates. Although significant advances have been made in manipulating microorganisms to produce useful products from organic substrates, engineering them to use carbon dioxide and hydrogen gas has not been reported. Herein, we describe a unique temperature-dependent approach that confers on a microorganism (the archaeon Pyrococcus furiosus, which grows optimally on carbohydrates at 100°C) the capacity to use carbon dioxide, a reaction that it does not accomplish naturally. This was achieved by the heterologous expression of five genes of the carbon fixation cycle of the archaeon Metallosphaera sedula, which grows autotrophically at 73°C. The engineered P. furiosus strain is able to use hydrogen gas and incorporate carbon dioxide into 3-hydroxypropionic acid, one of the top 12 industrial chemical building blocks. The reaction can be accomplished by cell-free extracts and by whole cells of the recombinant P. furiosus strain. Moreover, it is carried out some 30°C below the optimal growth temperature of the organism in conditions that support only minimal growth but maintain sufficient metabolic activity to sustain the production of 3-hydroxypropionate. The approach described here can be expanded to produce important organic chemicals, all through biological activation of carbon dioxide. DA - 2013/4/9/ PY - 2013/4/9/ DO - 10.1073/pnas.1222607110 VL - 110 IS - 15 SP - 5840-5845 SN - 0027-8424 KW - anaerobe KW - archaea KW - biotechnology KW - metabolic engineering KW - thermophile ER - TY - JOUR TI - Development of a New Positron Emission Tomography Tracer for Targeting Tumor Angiogenesis: Synthesis, Small Animal Imaging, and Radiation Dosimetry AU - Patterson, Cam AU - Frederick, C. Brandon AU - Yuan, Hong AU - Dyer, Laura A. AU - Lockyer, Pamela AU - Lalush, David S. AU - Veleva, Anka N. T2 - MOLECULES AB - Angiogenesis plays a key role in cancer progression and correlates with disease aggressiveness and poor clinical outcomes. Affinity ligands discovered by screening phage display random peptide libraries can be engineered to molecularly target tumor blood vessels for noninvasive imaging and early detection of tumor aggressiveness. In this study, we tested the ability of a phage-display-selected peptide sequence recognizing specifically bone marrow- derived pro-angiogenic tumor-homing cells, the QFP-peptide, radiolabeled with 64Cu radioisotope to selectively image tumor vasculature in vivo by positron emission tomography (PET). To prepare the targeted PET tracer we modified QFP-phage with the DOTA chelator and radiolabeled the purified QFP-phage-DOTA intermediate with 64Cu to obtain QFP-targeted radioconjugate with high radiopharmaceutical yield and specific activity. We evaluated the new PET tracer in vivo in a subcutaneous (s.c.) Lewis lung carcinoma (LLC) mouse model and conducted tissue distribution, small animal PET/CT imaging study, autoradiography, histology, fluorescence imaging, and dosimetry assessments. The results from this study show that, in the context of the s.c. LLC immunocompetent mouse model, the QFP-tracer can target tumor blood vessels selectively. However, further optimization of the biodistribution and dosimetry profile of the tracer is necessary to ensure efficient radiopharmaceutical applications enabled by the biological specificity of the QFP-peptide. DA - 2013/5// PY - 2013/5// DO - 10.3390/molecules18055594 VL - 18 IS - 5 SP - 5594-5610 SN - 1420-3049 KW - development of new 64Cu radiolabeled peptide KW - radiopharmaceuticals KW - targeted radioconjugates KW - positron emission tomography (PET) imaging KW - tumor angiogenesis KW - tumor aggressiveness KW - responses to therapy ER - TY - JOUR TI - Atmospheric plasma application to improve adhesion of electrospun nanofibers onto protective fabric AU - Vitchuli, Narendiran AU - Shi, Quan AU - Nowak, Joshua AU - Nawalakhe, Rupesh AU - Sieber, Michael AU - Bourham, Mohamed AU - Zhang, Xiangwu AU - McCord, Marian T2 - JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY AB - Nylon 6 electrospun nanofibers were deposited on plasma-pretreated woven fabric substrates with the objective of improving adhesion between them. The prepared samples were evaluated for adhesion strength and durability of nanofiber mats by carrying out peel strength, flex resistance, and abrasion resistance tests. The test results showed significant improvement in the adhesion of nanofiber mats on woven fabric substrates due to atmospheric plasma pretreatment. The samples also exhibited good flex and abrasion resistance characteristics. X-ray photoelectron spectroscopy and water contact angle analyses indicate that plasma pretreatment introduces radicals, increases the oxygen content on the substrate surface, and leads to formation of active chemical sites that may be responsible for enhanced cross-linking between the substrate fabric and the electrospun nanofibers, which in turn increases the adhesion properties. The work demonstrates that the plasma treatment of the substrate fabric prior to deposition of electrospun nanofiber mats is a promising method to prepare durable functional materials. DA - 2013/4/1/ PY - 2013/4/1/ DO - 10.1080/01694243.2012.727164 VL - 27 IS - 8 SP - 924-938 SN - 0169-4243 UR - https://publons.com/publon/7178346/ KW - adhesion KW - atmospheric pressure plasma KW - cross-linking KW - dielectric barrier discharge KW - electrospinning KW - water contact angle ER - TY - JOUR TI - Alternating current-dielectrophoresis driven on-chip collection and chaining of green microalgae in freshwaters AU - Suscillon, Coralie AU - Velev, Orlin D. AU - Slaveykova, Vera I. T2 - BIOMICROFLUIDICS AB - The capability of the AC dielectrophoresis (DEP) for on-chip capture and chaining of microalgae suspended in freshwaters was evaluated. The effects of freshwater composition as well as the electric field voltage, frequency, and duration, on the dielectrophoretic response of microalga Chlamydomonas reinhardtii were characterized systematically. Highest efficiency of cell alignment in one-dimensional arrays, determined by the percentage of cells in chain and the chain length, was obtained at AC-field of 20 V mm(-1) and 1 kHz applied for 600 s. The DEP response and cell alignment of C. reinhardtii in water sampled from lake, pond, and river, as well as model media were affected by the chemical composition of the media. In the model media, the efficiency of DEP chaining was negatively correlated to the conductivity of the cell suspensions, being higher in suspensions with low conductivity. The cells suspended in freshwaters, however, showed anomalously high chaining at long exposure times. High concentrations of nitrate and dissolved organic matter decrease cell chaining efficiency, while phosphate and citrate concentrations increase it and favor formation of longer chains. Importantly, the application of AC-field had no effect on algal autofluorescence, cell membrane damage, or oxidative stress damages in C. reinhardtii. DA - 2013/3// PY - 2013/3// DO - 10.1063/1.4801870 VL - 7 IS - 2 SP - SN - 1932-1058 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84877681853&partnerID=MN8TOARS KW - biomembranes KW - bioMEMS KW - cellular biophysics KW - electrophoresis KW - lakes KW - microfluidics KW - microorganisms KW - rivers KW - toxicology ER - TY - JOUR TI - A new strategy for ultralow biofouling membranes: Uniform and ultrathin hydrophilic coatings using liquid carbon dioxide AU - Susanti, Ratna F. AU - Han, Yang Soo AU - Kim, Jaehoon AU - Lee, Young Haeng AU - Carbonell, Ruben G. T2 - JOURNAL OF MEMBRANE SCIENCE AB - Highly stable, uniform and ultrathin hydrophilic polymer coatings on the surface as well as in the pores of a PVDF microfiltration (MF) membrane are obtained by coating a hydrophilic monomer in liquid carbon dioxide (l-CO2) followed by subsequent crosslinking reaction. Polyethylene glycol diacrylate (PEGDA, Mn ~258 g/mol) is used as the l-CO2 soluble hydrophilic monomer source and azobisisobutyronitrile (AIBN) was used as a radical initiator. The extremely low surface tension and the low viscosity of l-CO2 result in ultrathin and uniform PEG coatings on the hydrophobic polyvinylidene fluoride (PVDF) microfiltration membrane. The chemical composition, morphology, and the depth profiles of the PEG-coated membranes are characterized in detail using X-ray photoelectron spectroscopy, scanning electron microscopy, electron probe microanalysis and energy dispersive X-ray microanalysis. Long-term permeation flux test using a bovine serum albumin solution shows that the 1.0 wt% PEGDA-coated membrane using l-CO2 exhibits 1.34 times larger BSA solution flux than that of the uncoated PVDF membrane, and 1.3 times larger flux than that of a commercial hydrophilic membrane. Fouling resistance estimation shows that the 1 wt% PEGDA-coated membrane exhibits ~30% lower internal fouling resistance than the pristine membrane, and ~24% lower internal fouling resistance than the commercial hydrophilic membrane. DA - 2013/8/1/ PY - 2013/8/1/ DO - 10.1016/j.memsci.2013.03.068 VL - 440 SP - 88-97 SN - 1873-3123 KW - Hydrophilization KW - Liquid carbon dioxide KW - Coating KW - Biofouling ER - TY - JOUR TI - mRNA display selection and solid-phase synthesis of Fc-binding cyclic peptide affinity ligands AU - Menegatti, S. AU - Hussain, M. AU - Naik, A. D. AU - Carbonell, R. G. AU - Rao, B. M. T2 - Biotechnology and Bioengineering AB - Abstract Cyclic peptides are attractive candidates for synthetic affinity ligands due to their favorable properties, such as resistance to proteolysis, and higher affinity and specificity relative to linear peptides. Here we describe the discovery, synthesis and characterization of novel cyclic peptide affinity ligands that bind the Fc portion of human Immunoglobulin G (IgG; hFc). We generated an mRNA display library of cyclic pentapeptides wherein peptide cyclization was achieved with high yield and selectivity, using a solid‐phase crosslinking reaction between two primary amine groups, mediated by a homobifunctional linker. Subsequently, a pool of cyclic peptide binders to hFc was isolated from this library and chromatographic resins incorporating the selected cyclic peptides were prepared by on‐resin solid‐phase peptide synthesis and cyclization. Significantly, this approach results in resins that are resistant to harsh basic conditions of column cleaning and regeneration. Further studies identified a specific cyclic peptide—cyclo[ Link ‐M‐WFRHY‐K]—as a robust affinity ligand for purification of IgG from complex mixtures. The cyclo[ Link ‐M‐WFRHY‐K] resin bound selectively to the Fc fragment of IgG, with no binding to the Fab fragment, and also bound immunoglobulins from a variety of mammalian species. Notably, while the recovery of IgG using the cyclo[ Link ‐M‐WFRHY‐K] resin was comparable to a Protein A resin, elution of IgG could be achieved under milder conditions (pH 4 vs. pH 2.5). Thus, cyclo[ Link ‐M‐WFRHY‐K] is an attractive candidate for developing a cost‐effective and robust chromatographic resin to purify monoclonal antibodies (mAbs). Finally, our approach can be extended to efficiently generate and evaluate cyclic peptide affinity ligands for other targets of interest. Biotechnol. Bioeng. 2013; 110: 857–870. © 2012 Wiley Periodicals, Inc. DA - 2013/// PY - 2013/// DO - 10.1002/bit.24760 VL - 110 IS - 3 SP - 857–870 KW - cyclic peptide KW - mRNA display KW - Fc binding KW - affinity ligand KW - library ER - TY - JOUR TI - Role of 4-Hydroxybutyrate-CoA Synthetase in the CO2 Fixation Cycle in Thermoacidophilic Archaea AU - Hawkins, Aaron S. AU - Han, Yejun AU - Bennett, Robert K. AU - Adams, Michael W. W. AU - Kelly, Robert M. T2 - JOURNAL OF BIOLOGICAL CHEMISTRY AB - Metallosphaera sedula is an extremely thermoacidophilic archaeon that grows heterotrophically on peptides and chemolithoautotrophically on hydrogen, sulfur, or reduced metals as energy sources. During autotrophic growth, carbon dioxide is incorporated into cellular carbon via the 3-hydroxypropionate/4-hydroxybutyrate cycle (3HP/4HB). To date, all of the steps in the pathway have been connected to enzymes encoded in specific genes, except for the one responsible for ligation of coenzyme A (CoA) to 4HB. Although several candidates for this step have been identified through bioinformatic analysis of the M. sedula genome, none have been shown to catalyze this biotransformation. In this report, transcriptomic analysis of cells grown under strict H(2)-CO(2) autotrophy was consistent with the involvement of Msed_0406 and Msed_0394. Recombinant versions of these enzymes catalyzed the ligation of CoA to 4HB, with similar affinities for 4HB (K(m) values of 1.9 and 1.5 mm for Msed_0406 and Msed_0394, respectively) but with different rates (1.69 and 0.22 μmol × min(-1) × mg(-1) for Msed_0406 and Msed_0394, respectively). Neither Msed_0406 nor Msed_0394 have close homologs in other Sulfolobales, although low sequence similarity is not unusual for acyl-adenylate-forming enzymes. The capacity of these two enzymes to use 4HB as a substrate may have arisen from simple modifications to acyl-adenylate-forming enzymes. For example, a single amino acid substitution (W424G) in the active site of the acetate/propionate synthetase (Msed_1353), an enzyme that is highly conserved among the Sulfolobales, changed its substrate specificity to include 4HB. The identification of the 4-HB CoA synthetase now completes the set of enzymes comprising the 3HP/4HB cycle. DA - 2013/2/8/ PY - 2013/2/8/ DO - 10.1074/jbc.m112.413195 VL - 288 IS - 6 SP - 4012-4022 SN - 1083-351X ER - TY - JOUR TI - Real-time monitoring of high-gravity corn mash fermentation using in situ raman spectroscopy AU - Gray, Steven R. AU - Peretti, Steven W. AU - Lamb, H. Henry T2 - BIOTECHNOLOGY AND BIOENGINEERING AB - Abstract In situ Raman spectroscopy was employed for real‐time monitoring of simultaneous saccharification and fermentation (SSF) of corn mash by an industrial strain of Saccharomyces cerevisiae . An accurate univariate calibration model for ethanol was developed based on the very strong 883 cm −1 C–C stretching band. Multivariate partial least squares (PLS) calibration models for total starch, dextrins, maltotriose, maltose, glucose, and ethanol were developed using data from eight batch fermentations and validated using predictions for a separate batch. The starch, ethanol, and dextrins models showed significant prediction improvement when the calibration data were divided into separate high‐ and low‐concentration sets. Collinearity between the ethanol and starch models was avoided by excluding regions containing strong ethanol peaks from the starch model and, conversely, excluding regions containing strong saccharide peaks from the ethanol model. The two‐set calibration models for starch ( R 2 = 0.998, percent error = 2.5%) and ethanol ( R 2 = 0.999, percent error = 2.1%) provide more accurate predictions than any previously published spectroscopic models. Glucose, maltose, and maltotriose are modeled to accuracy comparable to previous work on less complex fermentation processes. Our results demonstrate that Raman spectroscopy is capable of real time in situ monitoring of a complex industrial biomass fermentation. To our knowledge, this is the first PLS‐based chemometric modeling of corn mash fermentation under typical industrial conditions, and the first Raman‐based monitoring of a fermentation process with glucose, oligosaccharides and polysaccharides present. Biotechnol. Bioeng. 2013; 110: 1654–1662. © 2013 Wiley Periodicals, Inc. DA - 2013/6// PY - 2013/6// DO - 10.1002/bit.24849 VL - 110 IS - 6 SP - 1654-1662 SN - 1097-0290 KW - Raman spectroscopy KW - fermentation KW - ethanol KW - biofuels KW - chemometrics ER - TY - JOUR TI - Reactive adsorption of ammonia and ammonia/water on CuBTC metal-organic framework: A ReaxFF molecular dynamics simulation AU - Huang, Liangliang AU - Bandosz, Teresa AU - Joshi, Kaushik L. AU - Duin, Adri C. T. AU - Gubbins, Keith E. T2 - JOURNAL OF CHEMICAL PHYSICS AB - We report ReaxFF molecular dynamics simulations for reactive adsorption of NH(3) on dehydrated CuBTC metal-organic framework. If the temperature is moderate (up to 125 °C), the dehydrated CuBTC demonstrates a good hydrostatic stability for water concentrations up to 4.0 molecules per copper site. However, if the temperature increases to 550 K, the dehydrated CuBTC will collapse even at a small water concentration, 1.0 H(2)O molecule per copper site. When NH(3) molecules are adsorbed in the channel and micropores of CuBTC, they prefer to chemisorb to the copper sites rather than forming a dimer with another NH(3) molecule. The formation of equimolar Cu(2)(NH(2))(4) and (NH(4))(3)BTC structures is observed at 348 K, which is in good agreement with previous experimental findings. The dehydrated CuBTC framework is partially collapsed upon NH(3) adsorption, while the Cu-Cu dimer structure remains stable under the investigated conditions. Further calculations reveal that the stability of CuBTC is related to the ammonia concentration. The critical NH(3) concentration after which the dehydrated CuBTC starts to collapse is determined to be 1.0 NH(3) molecule per copper site. Depending on whether NH(3) concentration is below or above the critical value, the dehydrated CuBTC can be stable to a higher temperature, 378 K, or can collapse at a lower temperature, 250 K. H(2)O∕NH(3) mixtures have also been studied, and we find that although water molecules do not demonstrate a strong interaction with the copper sites of CuBTC, the existence of water molecules can substantially prevent ammonia from interacting with CuBTC, and thus reduce the amount of chemisorbed NH(3) molecules on CuBTC and stabilize the CuBTC framework to some extent. DA - 2013/1/21/ PY - 2013/1/21/ DO - 10.1063/1.4774332 VL - 138 IS - 3 SP - SN - 1089-7690 ER - TY - JOUR TI - Polyvinylidene fluoride-co-chlorotrifluoroethylene and polyvinylidene fluoride-co-hexafluoropropylene nanofiber-coated polypropylene microporous battery separator membranes AU - Lee, Hun AU - Alcoutlabi, Mataz AU - Watson, Jill V. AU - Zhang, Xiangwu T2 - JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS AB - Abstract Nanofiber‐coated polypropylene (PP) separator membranes were prepared by coating a Celgard® microporous PP membrane with electrospun polyvinylidene fluoride‐ co ‐chlorotrifluoroethylene (PVDF‐ co ‐CTFE) and PVDF‐ co ‐CTFE/polyvinylidene fluoride‐ co ‐hexafluoropropylene (PVDF‐ co ‐HFP) nanofibers. Three PVDF polymer solutions of varying compositions were used in the preparation of the nanofiber coatings. Two of the polymer solutions were PVDF‐ co ‐CTFE blends made using different types of PVDF‐ co ‐HFP copolymers. The PVDF‐ co ‐CTFE and PVDF‐ co ‐CTFE/PVDF‐ co ‐HFP blend nanofiber coatings have been found to have comparable adhesion to the PP microporous membrane substrate. The electrolyte uptakes and separator–electrode adhesion properties of nanofiber‐coated membranes were evaluated. Both the electrolyte uptake and the separator–electrode adhesion were improved by the nanofiber coatings. The improvement in electrolyte update capacity is not only related to the gelation capability of the PVDF copolymer nanofibers, but also attributed to the increased porosity and capillary effect on nanofibrous structure of the electrospun nanofiber coatings. Enhancement of the separator–electrode adhesion was owing to the adhesion properties of the copolymer nanofiber coatings. Compared with the PVDF‐ co ‐CTFE/PVDF‐ co ‐HFP blend nanofiber coatings studied, the PVDF‐ co ‐CTFE coating was more effective in improving the electrolyte uptake and separator–electrode adhesion. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 DA - 2013/3/1/ PY - 2013/3/1/ DO - 10.1002/polb.23216 VL - 51 IS - 5 SP - 349-357 SN - 0887-6266 UR - https://publons.com/publon/26924690/ KW - Adhesion KW - Coatings KW - Electrospinning KW - Lithium-ion batteries KW - Nanofibers KW - PVDF-co-CTFE KW - PVDF-co-HFP KW - Separators ER - TY - JOUR TI - Novel atmospheric plasma enhanced chitosan nanofiber/gauze composite wound dressings AU - Nawalakhe, Rupesh AU - Shi, Quan AU - Vitchuli, Narendiran AU - Noar, Jesse AU - Caldwell, Jane M. AU - Breidt, Frederick AU - Bourham, Mohamed A. AU - Zhang, Xiangwu AU - McCord, Marian G. T2 - JOURNAL OF APPLIED POLYMER SCIENCE AB - Abstract Electrospun chitosan nanofibers were deposited onto atmospheric plasma treated cotton gauze to create a novel composite bandage with higher adhesion, better handling properties, enhanced bioactivity, and moisture management. Plasma treatment of the gauze substrate was performed to improve the durability of the nanofiber/gauze interface. The chitosan nanofibers were electrospun at 3–7% concentration in trifluoroacetic acid. The composite bandages were analyzed using peel, gelbo flex, antimicrobial assay, moisture vapor transmission rate, X‐ray photoelectron spectroscopy (XPS), absorbency, and air permeability tests. The peel test showed that plasma treatment of the substrate increased the adhesion between nanofiber layers and gauze substrate by up to four times. Atmospheric plasma pretreatment of the gauze fabric prior to electrospinning significantly reduced degradation of the nanofiber layer due to repetitive flexing. The chitosan nanofiber layer contributes significantly to the antimicrobial properties of the bandage. Air permeability and moisture vapor transport were reduced due to the presence of a nanofiber layer upon the substrate. XPS of the plasma treated cotton substrate showed formation of active sites on the surface, decrease in carbon content, and increase in oxygen content as compared to the untreated gauze. Deposition of chitosan nanofibers also increased the absorbency of gauze substrate. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 DA - 2013/7/15/ PY - 2013/7/15/ DO - 10.1002/app.38804 VL - 129 IS - 2 SP - 916-923 SN - 1097-4628 UR - https://publons.com/publon/274769/ KW - biomedical applications KW - biopolymers and renewable polymers KW - nanostructured polymers KW - composites ER - TY - JOUR TI - Molecular Dynamics Simulations of DPPC Bilayers Using "LIME", a New Coarse-Grained Model AU - Curtis, Emily M. AU - Hall, Carol K. T2 - JOURNAL OF PHYSICAL CHEMISTRY B AB - A new intermediate resolution model for phospholipids, LIME, designed for use with discontinuous molecular dynamics (DMD) simulations is presented. The implicit-solvent model was developed using a multiscale modeling approach in which the geometric and energetic parameters are obtained by collecting data from atomistic simulations of a system composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) molecules and explicit water. In the model, 14 coarse-grained sites that are classified as 1 of 6 types represent DPPC. DMD simulations performed on a random solution of DPPC resulted in the formation of a defect-free bilayer in less than 4 h. The bilayer formed quantitatively reproduces the main structural properties (e.g., area per lipid, bilayer thickness, bond order parameters) that are observed experimentally. In addition, the bilayer transitions from a liquid-crystalline phase to a tilted gel phase when the temperature is reduced. Transbilayer movement of a lipid from the bottom leaflet to the top leaflet is observed when the temperature is increased. DA - 2013/5/2/ PY - 2013/5/2/ DO - 10.1021/jp309712b VL - 117 IS - 17 SP - 5019-5030 SN - 1520-5207 ER - TY - JOUR TI - Metastable Cu(I)-Niobate Semiconductor with a Low-Temperature, Nanoparticle-Mediated Synthesis AU - Choi, Jonglak AU - King, Nacole AU - Maggard, Paul A. T2 - ACS NANO AB - A nanoparticle synthetic strategy for the preparation of a new metastable Cu(I)-niobate is described, and that involves multipored Li3NbO4 nanoparticles as a precursor. A hydrothermal reaction of HNbO3 and LiOH·H2O in PEG200 and water at ∼180 °C yields ∼15–40 nm Li3NbO4 particles. These particles are subsequently used in a solvothermal copper(I)-exchange reaction with excess CuCl at 150 °C. Heating these products within the used CuCl flux (mp = 430 °C) to 450 °C for 30 min yields ∼4–12 nm Cu2Nb8O21 crystalline nanoparticles, and for a heating time of 24 h yields μm-sized, rod-shaped crystals. The new structure was characterized by single-crystal X-ray diffraction to have a condensed network consisting of NbO7 polyhedra and chains of elongated CuO4 tetrahedra. The compound thermally decomposes starting at ∼250 °C and higher temperatures, depending on the particle sizes, owing to the loss of the weakly coordinated Cu(I) cations from the structure and a concurrent disproportionation reaction at its surfaces. Thus, conventional solid-state reactions involving higher temperatures and bulk reagents have proven unsatisfactory for its synthesis. The measured bandgap size is ∼1.43–1.65 eV (indirect) and shows a dependence on the particle sizes. Electronic structure calculations based on density functional theory show that the bandgap transition results from the excitation of electrons at the band edges between filled Cu(I) 3d10-orbitals and empty Nb(V) 4d0-orbitals, respectively. The p-type nature of the Cu2Nb8O21 particles was confirmed in photoelectrochemical measurements on polycrystalline films that show a strong photocathodic current under visible-light irradiation in aqueous solutions. These results demonstrate the general utility of reactive nanoscale precursors in the synthetic discovery of new Cu(I)-based semiconducting oxides and which also show promise for use in solar energy conversion applications. DA - 2013/2// PY - 2013/2// DO - 10.1021/nn305707f VL - 7 IS - 2 SP - 1699-1708 SN - 1936-086X KW - nanoscale synthesis KW - solar energy KW - metastability KW - copper niobate KW - lithium niobate ER - TY - JOUR TI - Inhibitory effect of lignin during cellulose bioconversion: The effect of lignin chemistry on non-productive enzyme adsorption AU - Rahikainen, Jenni L. AU - Martin-Sampedro, Raquel AU - Heikkinen, Harri AU - Rovio, Stella AU - Marjamaa, Kaisa AU - Tamminen, Tarja AU - Rojas, Orlando J. AU - Kruus, Kristiina T2 - BIORESOURCE TECHNOLOGY AB - The effect of lignin as an inhibitory biopolymer for the enzymatic hydrolysis of lignocellulosic biomass was studied; specially addressing the role of lignin in non-productive enzyme adsorption. Botanical origin and biomass pre-treatment give rise to differences in lignin structure and the effect of these differences on enzyme binding and inhibition were elucidated. Lignin was isolated from steam explosion (SE) pre-treated and non-treated spruce and wheat straw and used for the preparation of ultrathin films for enzyme binding studies. Binding of Trichoderma reesei Cel7A (CBHI) and the corresponding Cel7A-core, lacking the linker and the cellulose-binding domain, to the lignin films was monitored using a quartz crystal microbalance (QCM). SE pre-treatment altered the lignin structure, leading to increased enzyme adsorption. Thus, the positive effect of SE pre-treatment, opening the cell wall matrix to make polysaccharides more accessible, may be compromised by the structural changes of lignin that increase non-productive enzyme adsorption. DA - 2013/4// PY - 2013/4// DO - 10.1016/j.biortech.2013.01.075 VL - 133 SP - 270-278 SN - 1873-2976 KW - Lignin KW - Steam explosion pre-treatment KW - Cellulase binding KW - Trichoderma reesei Cel7A KW - Carbohydrate binding module ER - TY - JOUR TI - Analysis of the Murine Immune Response to Pulmonary Delivery of Precisely Fabricated Nano- and Microscale Particles AU - Roberts, Reid A. AU - Shen, Tammy AU - Allen, Irving C. AU - Hasan, Warefta AU - DeSimone, Joseph M. AU - Ting, Jenny P. Y. T2 - PLOS ONE AB - Nanomedicine has the potential to transform clinical care in the 21(st) century. However, a precise understanding of how nanomaterial design parameters such as size, shape and composition affect the mammalian immune system is a prerequisite for the realization of nanomedicine's translational promise. Herein, we make use of the recently developed Particle Replication in Non-wetting Template (PRINT) fabrication process to precisely fabricate particles across and the nano- and micro-scale with defined shapes and compositions to address the role of particle design parameters on the murine innate immune response in both in vitro and in vivo settings. We find that particles composed of either the biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) or the biocompatible polymer polyethylene glycol (PEG) do not cause release of pro-inflammatory cytokines nor inflammasome activation in bone marrow-derived macrophages. When instilled into the lungs of mice, particle composition and size can augment the number and type of innate immune cells recruited to the lungs without triggering inflammatory responses as assayed by cytokine release and histopathology. Smaller particles (80×320 nm) are more readily taken up in vivo by monocytes and macrophages than larger particles (6 µm diameter), yet particles of all tested sizes remained in the lungs for up to 7 days without clearance or triggering of host immunity. These results suggest rational design of nanoparticle physical parameters can be used for sustained and localized delivery of therapeutics to the lungs. DA - 2013/4/12/ PY - 2013/4/12/ DO - 10.1371/journal.pone.0062115 VL - 8 IS - 4 SP - SN - 1932-6203 ER - TY - JOUR TI - Affinity membrane development from PBT nonwoven by photo-induced graft polymerization, hydrophilization and ligand attachment AU - Liu, Haiyan AU - Zheng, Yong AU - Gurgel, Patrick V. AU - Carbonell, Ruben G. T2 - JOURNAL OF MEMBRANE SCIENCE AB - Nonwoven fabrics are of great interest as potential materials for bioseparations due to their interconnected porous structure, relatively high surface area and low cost. In this paper we focus on the development of a potentially disposable affinity membrane for pathogen removal from biological systems such as human plasma. Poly glycidyl methacrylate (polyGMA) was grafted on the fiber surface of a polybutylene terephthalate (PBT) nonwoven using photo-induced graft polymerization. SEM and FTIR were used to characterize the pore structure and surface chemistry of the resulting material. To minimize nonspecific protein binding and hydrophilize the material, diethylene glycol (DEG) and diol groups were attached covalently to the grafted layer of polyGMA. The amount of nonspecific binding was quantified by the adsorption of bovine serum albumin (BSA) and an E. coli extract. The results showed that the grafted matrix containing DEG or diol groups bound significantly less total protein, compared with unmodified material. The DEG modified membrane was further developed by attachment of a specific proprietary ligand that binds to the prion protein, the agent responsible for transmissible spongiform encephalopathies. The affinity membrane showed good selectivity for the capture of prion protein from hamster brain homogenate. DA - 2013/2/1/ PY - 2013/2/1/ DO - 10.1016/j.memsci.2012.09.047 VL - 428 SP - 562-575 SN - 0376-7388 KW - Affinity membrane KW - Functional nonwoven fabrics KW - Surface modification KW - Protein purification KW - Nonspecific protein adsorption ER - TY - JOUR TI - A thermophile under pressure: Transcriptional analysis of the response of Caldicellulosiruptor saccharolyticus to different H-2 partial pressures AU - Bielen, Abraham A. M. AU - Verhaart, Marcel R. A. AU - VanFossen, Amy L. AU - Blumer-Schuette, Sara E. AU - Stams, Alfons J. M. AU - Oost, John AU - Kelly, Robert M. AU - Kengen, Serve W. M. T2 - INTERNATIONAL JOURNAL OF HYDROGEN ENERGY AB - Increased hydrogen (H2) levels are known to inhibit H2 formation in Caldicellulosiruptor saccharolyticus. To investigate this organism's strategy for dealing with elevated H2 levels the effect of the hydrogen partial pressure (PH2) on fermentation performance was studied by growing cultures under high and low PH2 in a glucose limited chemostat setup. Transcriptome analysis revealed the upregulation of genes involved in the disposal of reducing equivalents under high PH2, like lactate dehydrogenase and alcohol dehydrogenase as well as the NADH-dependent and ferredoxin-dependent hydrogenases. These findings are in line with the observed shift in fermentation profiles from acetate production to the production of acetate, lactate and ethanol under high PH2. Moreover, differential transcription was observed for genes involved in carbon metabolism, fatty acid biosynthesis and several transport systems. In addition, presented transcription data provide evidence for the involvement of the redox sensing Rex protein in gene regulation under high PH2 cultivation conditions. DA - 2013/2/12/ PY - 2013/2/12/ DO - 10.1016/j.ijhydene.2012.11.082 VL - 38 IS - 4 SP - 1837-1849 SN - 1879-3487 KW - Caldicellulosiruptor saccharolyticus KW - Hydrogen partial pressure KW - Chemostat KW - Metabolic shift KW - Gene expression KW - Rex transcriptional regulator ER - TY - JOUR TI - Structure control and performance improvement of carbon nanofibers containing a dispersion of silicon nanoparticles for energy storage AU - Li, Ying AU - Guo, Bingkun AU - Ji, Liwen AU - Lin, Zhan AU - Xu, Guanjie AU - Liang, Yinzheng AU - Zhang, Shu AU - Toprakci, Ozan AU - Hu, Yi AU - Alcoutlabi, Mataz AU - Zhang, Xiangwu T2 - CARBON AB - Si/C composite nanofibers were prepared by electrospinning and carbonization using polyacrylonitrile (PAN) as the spinning medium and carbon precursor. The nanofibers were used as lithium-ion battery anodes to combine the advantages of carbon (long cycle life) and silicon (high storage capacity) materials. The effects of Si particle size, Si content, and carbonization temperature on the structure and electrochemical performance of the anodes were investigated. Results show that anodes made from a 15 wt.% Si/PAN precursor with a Si particle size of 30–50 nm and carbonization temperature of 800 °C exhibit the best performance in terms of high capacity and stable cycling behavior. It is demonstrated that with careful structure control, Si/C composite nanofiber anodes are a promising material for next-generation lithium-ion batteries. DA - 2013/1// PY - 2013/1// DO - 10.1016/j.carbon.2012.08.027 VL - 51 SP - 185-194 SN - 1873-3891 UR - https://publons.com/publon/674384/ ER - TY - JOUR TI - Reaction pathways for butanoic acid decarboxylation on the (111) surface of a Pd nanoparticle AU - Lamb, H. Henry AU - Sremaniak, Laura AU - Whitten, Jerry L. T2 - SURFACE SCIENCE AB - Many-electron theory is applied to investigate decarboxylation of butanoic acid on the (111) surface of a Pd42 nanoparticle. Butanoic acid adsorbs weakly as an intact molecule (ΔH = − 28 kJ/mol) with the COOH moiety nearly parallel to the surface. In comparison, dissociative adsorption of butanoic acid to form surface butanoate (PrCOO) species and adsorbed H is exothermic by only 5 kJ/mol. Pathways for propane and CO2 formation are presented starting from adsorbed butanoic acid, PrCOO (ads) and a RCHCOO (R = C2H5) surface intermediate. An intramolecular pathway involves rotating the H of COOH toward the target (alpha) carbon. Following a series of bond distortions, the H is close enough to the target C to form a stretched HC bond. After propane begins to form, CO2 linearizes and CC dissociation is energetically favorable and rapid. Reaction of PrCOO (ads) and H (ads) also results in direct formation of propane and CO2. The energy barriers for H insertion are ~ 100 kJ/mol for both pathways; however, the dissociative pathway involves a high-energy precursor state with H in a 3-fold site under the CC bond undergoing reaction. An alternative decarboxylation pathway starting from RCHCOO leads to gas-phase CO2 and propylidene (in the absence of adsorbed H) or propyl (via insertion of adsorbed H) with energy barriers of 75 and 32 kJ/mol, respectively. The energy of the RCHCOO intermediate relative to gas-phase butanoic acid increases from 43 to 109 kJ/mol in the presence of adsorbed H, compensating for the lower decomposition barrier. DA - 2013/1// PY - 2013/1// DO - 10.1016/j.susc.2012.08.023 VL - 607 SP - 130-137 SN - 1879-2758 KW - Configuration interaction theory KW - Palladium KW - Fatty acid KW - Adsorption KW - Decarboxylation KW - Transition state KW - Adsorbed hydrogen ER - TY - JOUR TI - Production of polyhydroxybutyrate (PHB) by Alcaligenes latus using sugarbeet juice AU - Wang, Bingqing AU - Sharma-Shivappa, Ratna R. AU - Olson, Jonathan W. AU - Khan, Saad A. T2 - INDUSTRIAL CROPS AND PRODUCTS AB - The practicality of using sugarbeet juice as medium to grow Alcaligenes latus (ATCC 29714) for production of polyhydroxybutyrate (PHB), a biodegradable plastic, was explored in this study. Dilute sugarbeet juice, sugarbeet juice with partial and complete addition of nutrients other than sugar were used as culture media. Media with partial nutrient addition was shown to be optimal for PHB production, with final dry cell weight (DCW) 10.30 ± 1.01 g/L, PHB concentration 4.01 ± 0.95 g/L, PHB content 38.66 ± 7.28%, Yp/x (g PHB produced per g dry cell weight) 0.39 ± 0.07 and a maximum PHB productivity of 0.22 ± 0.01 g/L h. The melting temperature of PHB extracted from sugarbeet juice-grown cells supplemented with partial nutrients was measured to be 151.46 °C with crystallinity of 43.12% and the corresponding crystallinity temperature of 45.42 °C. Thermal degradation of extracted PHB occurred from 255.14 to 283.69 °C with the degradation peak at 273.86 °C. DA - 2013/5// PY - 2013/5// DO - 10.1016/j.indcrop.2012.08.011 VL - 43 SP - 802-811 SN - 1872-633X KW - Biodegradable plastics KW - Polyhydroxyalkanoate (PHA) KW - Sucrose KW - Two-stage batch fermentation ER - TY - JOUR TI - Preparation and properties of nanofiber-coated composite membranes as battery separators via electrospinning AU - Alcoutlabi, Mataz AU - Lee, Hun AU - Watson, Jill V. AU - Zhang, Xiangwu T2 - JOURNAL OF MATERIALS SCIENCE DA - 2013/3// PY - 2013/3// DO - 10.1007/s10853-012-7064-0 VL - 48 IS - 6 SP - 2690-2700 SN - 1573-4803 UR - https://publons.com/publon/7178345/ ER - TY - JOUR TI - Flame chemistry of tetrahydropyran as a model heteroatomic biofuel AU - Labbe, Nicole J. AU - Seshadri, Vikram AU - Kasper, Tina AU - Hansen, Nils AU - Oßwald, Patrick AU - Westmoreland, Phillip R. T2 - Proceedings of the Combustion Institute AB - Abstract The flame chemistry of tetrahydropyran (THP), a cyclic ether, has been examined using vacuum-ultraviolet (VUV)-photoionization molecular-beam mass spectrometry (PI-MBMS) and flame modeling, motivated by the need to understand and predict the combustion of oxygen-containing, biomass-derived fuels. Species identifications and mole-fraction profiles are presented for a fuel-rich ( Φ  = 1.75), laminar premixed THP–oxygen–argon flame at 2.66 kPa (20.0 Torr). Flame species with up to six heavy atoms have been detected. A detailed reaction set was developed for THP combustion that captures relevant features of the THP flame quite well, allowing analysis of the dominant kinetic pathways for THP combustion. Necessary rate coefficients and transport parameters were calculated or were estimated by analogies with a recent reaction set [Li et al., Combust. Flame 158 (2011) 2077–2089], and necessary thermochemical properties were computed using the CBS-QB3 method. Our results show that under the low-pressure conditions, THP destruction is dominated by H-abstraction, and the three resulting THP-yl radicals decompose primarily by β -scissions to two- and four-heavy-atom species that are generally destroyed by β -scission, abstraction, or oxidation. DA - 2013/1// PY - 2013/1// DO - 10.1016/j.proci.2012.07.027 VL - 34 IS - 1 SP - 259-267 J2 - Proceedings of the Combustion Institute LA - en OP - SN - 1540-7489 UR - http://dx.doi.org/10.1016/j.proci.2012.07.027 DB - Crossref KW - Molecular-beam mass spectrometry KW - Kinetics KW - Flat flame KW - Modeling KW - Quantum chemistry ER - TY - JOUR TI - Tuning morphology of mesoporous titanium oxides through fluorinated surfactants-based systems AU - Ruso, J. M. AU - Blanco, E. AU - Messina, P. V. T2 - Journal of Porous Materials DA - 2013/// PY - 2013/// VL - 20 IS - 1 SP - 95-105 ER - TY - JOUR TI - Fabrication of nanofiber meltblown membranes and their filtration properties AU - Hassan, Mohammad Abouelreesh AU - Yeom, Bong Yeol AU - Wilkie, Arnold AU - Pourdeyhimi, Behnam AU - Khan, Saad. A. T2 - JOURNAL OF MEMBRANE SCIENCE AB - Meltblowing is a unique one-step process for producing self-bonded fibrous nonwoven membranes directly from polymer resins, with average fiber diameter ranging between 1 and 2 μm. Determining routes for making nano- or submicron-fibers using this process are desirable since there are many manufacturing assets that are already in place. It is envisaged that these nonwoven membranes will find applications in critical areas such as medical, hygiene, filtration, bioseparation, and others. In this study, we investigate the influence of different die configurations and operating conditions on fiber and web characteristics. We also report on strategies for reducing the fiber size below one micron to achieve higher filtration quality at lower basis weight relative to the conventional meltblown webs. Their performance is compared to a control meltblown sample produced by using a typical die design. We find that production of nano-meltblown membranes with an average fiber size in the range of 300–500 nm using this new die design is possible and report on process operating conditions that result in such structures. These samples achieve equal filtration efficiencies to that of our control sample at 88% reduced basis weight but at a lower polymer throughput. The lower basis weight also resulted in a lower pressure drop and overall, the new samples exhibited a higher quality factor, twice that of the control. These results show significant promise for the use of nano-meltblown fibers in filtration applications. DA - 2013/1// PY - 2013/1// DO - 10.1016/j.memsci.2012.09.050 VL - 427 SP - 336-344 SN - 1873-3123 KW - Nanofibers KW - Meltbowing KW - Filtration KW - Nonwoven membranes KW - HEPA filters ER -