@article{beachler_gracz_morgan_bembenek bailey_borst_ellis_von dollen_lyle_nebel_andrews_et al._2021, title={Plasma metabolomic profiling of healthy pregnant mares and mares with experimentally induced placentitis}, volume={53}, ISSN={["2042-3306"]}, DOI={10.1111/evj.13262}, abstractNote={BACKGROUND
Metabolomics may represent an avenue for diagnosis of equine ascending placentitis.


OBJECTIVES
To characterise the plasma metabolomic profile in healthy mares and mares with induced ascending placentitis, with the goal of identifying metabolites with potential clinical value for early diagnosis of placentitis.


STUDY DESIGN
Controlled in vivo experiment.


METHODS
Placentitis was induced in 10 late-term pregnant pony mares via Streptococcal equi subsp. zooepidemicus inoculation in five mares between days 285 and 290 of gestation, while five mares served as healthy controls. Repeated ultrasound examinations and jugular venipuncture were performed to obtain combined thickness of the uterus and placenta (CTUP) and plasma for NMR spectroscopy. Mares with increased CTUP were diagnosed with placentitis and treated in accordance with published therapeutic recommendations. NMR metabolomic analysis was performed to identify and quantify plasma metabolites at each time-point. Concentrations were compared using ANOVA with repeated measures and PLS-DA analysis.


RESULTS
Four hours post-inoculation, a significant increase was detected in the metabolites alanine, phenylalanine, histidine, pyruvate, citrate, glucose, creatine, glycolate, lactate, and 3-hydroxyisobutyrate that returned to baseline by 12 hours. On day 4, a significant reduction in the metabolites alanine, phenylalanine, histidine, tyrosine, pyruvate, citrate, glycolate, lactate, and dimethylsulfone was seen in infected mares compared to controls.


MAIN LIMITATIONS
There were small numbers of mares within groups. Additionally, this work compares healthy animals to animals treated with multimodal therapeutics following diagnosis of placentitis without an untreated cohort.


CONCLUSIONS
Two phases of metabolite changes were noted after experimental infection: An immediate rise in metabolite concentration involved in energy, nitrogen, hydrogen, and oxygen metabolism within 4 hours after inoculation that was followed by a decrease in metabolite concentrations involved in energy and nitrogen metabolism at 4 days, coinciding with ultrasonographic diagnosis of placentitis.}, number={1}, journal={Equine Veterinary Journal}, author={Beachler, T.M. and Gracz, H.S. and Morgan, D.R. and Bembenek Bailey, S.A. and Borst, L. and Ellis, K.E. and Von Dollen, K.A. and Lyle, S.K. and Nebel, A.M. and Andrews, N.C. and et al.}, year={2021}, month={Jan}, pages={85–93} }
 @article{green_jr_carey_morgan_gracz_sherman_rodriguez_edward l. d'antonio_2021, title={Synthesis, biochemical, and biological evaluation of C2 linkage derivatives of amino sugars, inhibitors of glucokinase from Trypanosoma cruzi}, volume={47}, ISSN={["1464-3405"]}, DOI={10.1016/j.bmcl.2021.128227}, abstractNote={Eighteen amino sugar analogues were screened against Trypanosoma cruzi glucokinase (TcGlcK), a potential drug-target of the protozoan parasite in order to assess for viable enzyme inhibition. The analogues were divided into three amino sugar scaffolds that included d-glucosamine (d-GlcN), d-mannosamine (d-ManN), and d-galactosamine (d-GalN); moreover, all but one of these compounds were novel. TcGlcK is an important metabolic enzyme that has a role in producing G6P for glycolysis and the pentose phosphate pathway (PPP). The inhibition of these pathways via glucose kinases (i.e., glucokinase and hexokinase) appears to be a strategic approach for drug discovery. Glucose kinases phosphorylate d-glucose with co-substrate ATP to yield G6P and the formed G6P enters both pathways for catabolism. The compound screen revealed five on-target confirmed inhibitors that were all from the d-GlcN series, such as compounds 1, 2, 4, 5, and 6. Four of these compounds were strong TcGlcK inhibitors (1, 2, 4, and 6) since they were found to have micromolar inhibitory constant (Ki) values around 20 μM. Three of the on-target confirmed inhibitors (1, 5, and 6) revealed notable in vitro anti-T. cruzi activity with IC50 values being less than 50 μM. Compound 1 was benzoyl glucosamine (BENZ-GlcN), a known TcGlcK inhibitor that was the starting point for the design of the compounds in this study; in addition, TcGlcK - compound 1 inhibition properties were previously determined [D'Antonio, E. L. et al. (2015) Mol. Biochem. Parasitol. 204, 64-76]. As such, compounds 5 and 6 were further evaluated biochemically, where formal Ki values were determined as well as their mode of TcGlcK inhibition. The Ki values determined for compounds 5 and 6 were 107 ± 4 μM and 15.2 ± 3.3 μM, respectively, and both of these compounds exhibited the competitive inhibition mode.}, journal={BIOORGANIC & MEDICINAL CHEMISTRY LETTERS}, author={Green, Scott B. and Jr, Robert J. Lanier and Carey, Shane M. and Morgan, David R. and Gracz, Hanna and Sherman, Julian and Rodriguez, Ana and Edward L. D'Antonio}, year={2021}, month={Sep} }
 @article{beachler_bailey_gracz_morgan_von dollen_ellis_gadsby_lyle_2020, title={Metabolomic Profile of Allantoic and Amniotic Fluid in Late-term Gestational Mares Characterized by H-1-nuclear Magnetic Resonance Spectroscopy}, volume={94}, ISSN={["1542-7412"]}, DOI={10.1016/j.jevs.2020.103235}, abstractNote={The amniotic and allantoic fluid compartments in the mare serve essential roles throughout pregnancy and parturition. Although the global metabolomic profile of amniotic fluid in women has been extensively characterized, current data for equine fetal fluids are limited. Therefore, the goal of this study was to characterize the global metabolomic profile of equine allantoic and amniotic fluid through nuclear magnetic resonance spectroscopy. Fetal fluids were collected between 270 and 295 days of gestation from 12 pregnancies through ultrasound-guided transabdominal puncture. A total of 24 samples (n = 10 allantoic fluid; n = 9 amniotic fluid; n = 5 admixed fluid) were analyzed by one-dimensional proton (1H) and two-dimensional (1H-13 C) nuclear magnetic resonance spectroscopy. Metabolites were integrated and compared between fluid types using a Kruskal-Wallis test at P < .05 significance. A total of 28 distinct metabolites were found in allantoic and admixed fluid, whereas 23 metabolites were identified in amniotic fluid. Allantoic fluid contained significant elevations (P < .05) in the metabolites betaine, creatine, creatinine, citrate, histidine, nitrophenol, tryptophan, π-methylhistidine, and unknown metabolite #1 compared with amniotic fluid, whereas amniotic fluid contained statistically increased concentrations of the metabolite lactate compared with allantoic fluid (P = .003).}, journal={JOURNAL OF EQUINE VETERINARY SCIENCE}, author={Beachler, Theresa M. and Bailey, C. Scott and Gracz, Hanna S. and Morgan, Davic R. and Von Dollen, Karen A. and Ellis, Katey E. and Gadsby, John E. and Lyle, Sara K.}, year={2020}, month={Nov} }
 @article{beachler_gracz_long_borst_morgan_nebel_andrews_koipillai_frable_bailey_et al._2019, title={Allantoic Metabolites, Progesterone, and Estradiol-17 beta Remain Unchanged After Infection in an Experimental Model of Equine Ascending Placentitis}, volume={73}, ISSN={["1542-7412"]}, DOI={10.1016/j.jevs.2018.11.014}, abstractNote={The objective of this study was to characterize the metabolomic profile of equine allantoic fluid in the pregnant mare with and without experimentally induced ascending placentitis with the goal of identifying biomarkers of this disease. We compared the onset of metabolomic changes with common modalities for diagnosis of ascending placentitis, including measurement of the combined thickness of the uterus and placenta (CTUP), hormonal profiling, and measurement of serum acute phase proteins. Ten pregnant pony mares were randomly divided into two groups: five healthy control mares (CONT) and five mares induced to develop ascending placentitis (PLAC) via inoculation with Streptococcus equi subsp. zooepidemicus bacteria at Days 280–285 of gestation. Allantoic fluid, whole blood, and serum were collected from both groups at 270–275 days of gestation and at the following time points postinoculation: 4 hours, Days 2, 4, 6, and 10. Differences between groups in identified metabolites, progesterone, estradiol-17β, lactate, and serum amyloid A (SAA) were assessed using an analysis of variance with repeated measures. A total of 27 metabolites were identified in allantoic fluid. No differences were detected between groups at any time point (P > .05) for any identified metabolite, progesterone, estradiol-17β, or lactate concentrations. Significant elevations in CTUP (P = .003) and SAA (P = .0001) were detected by Days 4 and 6 postinoculation, respectively. The results of this study established a database of equine allantoic fluid metabolites and confirmed the utility of uteroplacental ultrasound for detection of placentitis before the onset of hematologic changes.}, journal={JOURNAL OF EQUINE VETERINARY SCIENCE}, author={Beachler, Theresa and Gracz, Hanna and Long, Nathan M. and Borst, Luke and Morgan, David and Nebel, Amber and Andrews, Natalie and Koipillai, Joanna and Frable, Samantha and Bailey, Stasia Bembenek and et al.}, year={2019}, month={Feb}, pages={95–105} }
 @article{jardim_du_hart_lucia_jameel_chang_gracz_2019, title={Fundamental molecular characterization and comparison of the 0, D-0, and E stage effluents from hardwood pulp bleaching}, volume={18}, ISSN={["0734-1415"]}, DOI={10.32964/TJ18.6.341}, abstractNote={The present study characterized effluents from the O, D0, and E stages using nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques to better understand the chemical nature of the dissolved organics formed from the bleaching of a high-yield hardwood kraft pulp. Understanding the structures and molecular weight distribution of these organics is the first step in developing methods to mitigate these contaminates in the discharged effluents. The results indicated that the molecular weight distribution (MWD) of the dissolved organics from oxygen delignification effluent is broader than those from D0 and E stage effluents. In addition, the O stage filtrate contained considerable amounts of lignin and xylan fragments, which showed its efficiency in removing such materials. The effluent from the D0 stage contained a lower amount of high molecular weight fragments and a higher amount of low molecular weight fragments versus the O-stage filtrate. Aromatic structures were nearly absent in the D0 stage filtrate, but the degraded organic material, presumably from oxidized lignin, contained olefinic (C=C) and carbonyl (C=O) functional groups. Furthermore, higher molecular weight fragments were detected in the E-stage effluent, presumably due to the extensive solubilization and removal of the oxidized lignin generated from the D0 pulp.}, number={6}, journal={TAPPI JOURNAL}, author={Jardim, Juliana M. and Du, Xueyu and Hart, Peter W. and Lucia, Lucian and Jameel, Hasan and Chang, Hou-Min and Gracz, Hanna}, year={2019}, month={Jun}, pages={341–351} }
 @article{bembenek-bailey_niemuth_mcclellan-green_godfrey_harms_gracz_stoskopf_2019, title={NMR Metabolomic Analysis of Skeletal Muscle, Heart, and Liver of Hatchling Loggerhead Sea Turtles (Caretta caretta) Experimentally Exposed to Crude Oil and/or Corexit}, volume={9}, ISSN={2218-1989}, url={http://dx.doi.org/10.3390/metabo9020021}, DOI={10.3390/metabo9020021}, abstractNote={We used nuclear magnetic spectroscopy (NMR) to evaluate the metabolic impacts of crude oil, Corexit 5900A, a dispersant, and a crude oil Corexit 5900A mixture exposure on skeletal muscle, heart, and liver physiology of hatchling loggerhead sea turtles (Caretta caretta). Tissue samples were obtained from 22 seven-day-old hatchlings after a four day cutaneous exposure to environmentally relevant concentrations of crude oil, Corexit 5900A, a combination of crude oil and Corexit 9500A, or a seawater control. We identified 38 metabolites in the aqueous extracts of the liver, and 30 metabolites in both the skeletal and heart muscle aqueous extracts, including organic acids/osmolytes, energy compounds, amino acids, ketone bodies, nucleosides, and nucleotides. Skeletal muscle lactate, creatines, and taurine concentrations were significantly lower in hatchlings exposed to crude oil than in control hatchlings. Lactate, taurine, and cholines appeared to be the basis of some variation in hatchling heart samples, and liver inosine, uracil, and uridine appeared to be influenced by Corexit and crude oil exposure. Observed decreases in concentrations of lactate and creatines may reflect energy depletion in skeletal muscle of oil-exposed animals, while decreased taurine concentrations in these animals may reflect higher oxidative stress.}, number={2}, journal={Metabolites}, publisher={MDPI AG}, author={Bembenek-Bailey, Stasia and Niemuth, Jennifer and McClellan-Green, Patricia and Godfrey, Matthew and Harms, Craig and Gracz, Hanna and Stoskopf, Michael}, year={2019}, month={Jan}, pages={21} }
 @article{feese_gracz_boyle_ghiladi_2019, title={Towards microbe-targeted photosensitizers: Synthesis, characterization and in vitro photodynamic inactivation of the tuberculosis model pathogen M. smegmatis by porphyrin-peptide conjugates}, volume={23}, ISSN={1088-4246 1099-1409}, url={http://dx.doi.org/10.1142/S1088424619501505}, DOI={10.1142/S1088424619501505}, abstractNote={Porphyrin-peptide conjugates have a breadth of potential applications, including use in photodynamic therapy, boron neutron capture therapy, as fluorescence imaging tags for tracking subcellular localization, as magnetic resonance imaging (MRI) positive-contrast reagents and as biomimetic catalysts. Here, we have explored three general routes to porphyrin-peptide conjugates using the Cu(I)-catalyzed Huisgen-Medal-Sharpless 1,3-dipolar cycloaddition of peptide-containing azides with a terminal alkyne-containing porphyrin, thereby generating porphyrin-peptide conjugates (PPCs) comprised of a cationic porphyrin coupled to short antimicrobial peptides. In addition to characterizing the PPCs using a variety of spectroscopic (UV-vis, [Formula: see text]H- and [Formula: see text]C-NMR) and mass spectrometric methods, we evaluated their efficacy as photosensitizers for the in vitro photodynamic inactivation of Mycobacterium smegmatis as a model for the pathogen Mycobacterium tuberculosis. Difficulties that needed to be overcome for the efficient synthesis of PPCs were the limited solubility of the quaternized pyridyl porphyrin in common solvents, undesired (de)metallation and transmetallation, and chromatographic purification. Photodynamic inactivation studies of a small library of PPCs against Mycobacterium smegmatis confirmed our hypothesis that the porphyrin-based photosensitizer maintains its ability to efficiently inactivate bacteria when conjugated to a small peptide by upwards of 5–6 log units (99.999[Formula: see text]%) using white light illumination (400–700 nm, 60 mW/cm[Formula: see text], 30 min). Further, hemolysis assays revealed the lack of toxicity of the PPCs against sheep blood at concentrations employed for in vitro photodynamic inactivation. Taken together, the results demonstrated the ability of PPCs to maintain their antimicrobial photodynamic inactivation efficacy when possessing a short cationic peptides for enabling the potential targeting of pathogens in vivo.}, number={11n12}, journal={Journal of Porphyrins and Phthalocyanines}, publisher={World Scientific Pub Co Pte Lt}, author={Feese, Elke and Gracz, Hanna S. and Boyle, Paul D. and Ghiladi, Reza A.}, year={2019}, month={Dec}, pages={1414–1439} }
 @article{zhao_xue_gudanis_gracz_findenegg_gdaniec_franzen_2018, title={Dynamics of dehaloperoxidase-hemoglobin A derived from NMR relaxation spectroscopy and molecular dynamics simulation}, volume={181}, ISSN={["1873-3344"]}, DOI={10.1016/j.jinorgbio.2018.01.006}, abstractNote={Dehaloperoxidase-hemoglobin is the first hemoglobin identified with biologically-relevant oxidative functions, which include peroxidase, peroxygenase and oxidase activities. Herein we report a study of the protein backbone dynamics of DHP using heteronuclear NMR relaxation methods and molecular dynamics (MD) simulations to address the role of protein dynamics in switching from one function to another. The results show that DHP's backbone helical regions and turns have average order parameters of S2 = 0.87 ± 0.03 and S2 = 0.76 ± 0.08, respectively. Furthermore, DHP is primarily a monomer in solution based on the overall tumbling correlation time τm is 9.49 ± 1.65 ns calculated using the prolate diffusion tensor model in the program relax. A number of amino acid residues have significant Rex using the Lipari-Szabo model-free formalism. These include Lys3, Ile6, Leu13, Gln18, Arg32, Ser48, Met49, Thr56, Phe60, Arg69, Thr71 Cys73, Ala77, Asn81, Gly95, Arg109, Phe115, Leu127 and Met136, which may experience slow conformational motions on the microseconds-milliseconds time scale according to the model. Caution should be used when the model contains >4 fitting parameters. The program caver3.0 was used to identify tunnels inside DHP obtained from MD simulation snapshots that are consistent with the importance of the Xe binding site, which is located at the central intersection of the tunnels. These tunnels provide diffusion pathways for small ligands such as O2, H2O and H2O2 to enter the distal pocket independently of the trajectory of substrates and inhibitors, both of which are aromatic molecules.}, journal={JOURNAL OF INORGANIC BIOCHEMISTRY}, author={Zhao, Jing and Xue, Mengjun and Gudanis, Dorota and Gracz, Hanna and Findenegg, Gerhard H. and Gdaniec, Zofia and Franzen, Stefan}, year={2018}, month={Apr}, pages={65–73} }
 @article{westmoreland_niemuth_gracz_stoskopf_2017, title={Altered acrylic acid concentrations in hard and soft corals exposed to deteriorating water conditions}, volume={2}, url={https://dx.doi.org/10.1139/facets-2016-0064}, DOI={10.1139/facets-2016-0064}, abstractNote={A reliable marker of early coral response to environmental stressors can help guide decision-making to mitigate global coral reef decline by detecting problems before the development of clinically observable disease. We document the accumulation of acrylic acid in two divergent coral taxa, stony small polyp coral (Acropora sp.) and soft coral (Lobophytum sp.), in response to deteriorating water quality characterized by moderately increased ammonia (0.25 ppm) and phosphate (0.15 ppm) concentrations and decreased calcium (360 ppm) concentration, using nuclear magnetic resonance spectroscopy (NMR)-based metabolomic techniques. Changes in acrylic acid concentration in polyp tissues free of zooxanthellae suggest that acrylic acid could be a product of animal metabolism and not exclusively a metabolic by-product of the osmolyte dimethylsulfoniopropionate (DMSP) in marine algae or bacteria. Our findings build on previously documented depletions of acrylic acid in wild coral potentially correlated to temperature ...}, journal={FACETS}, publisher={Canadian Science Publishing}, author={Westmoreland, Lori S.H. and Niemuth, Jennifer N. and Gracz, Hanna S. and Stoskopf, Michael K.}, editor={Macdonald, Robie W.Editor}, year={2017}, month={Jun}, pages={531–544} }
 @article{gross_jensen_gracz_dancer_keener_2017, title={Evaluation of physical and chemical properties and their interactions in fat, oil, and grease (FOG) deposits}, volume={123}, ISSN={["0043-1354"]}, DOI={10.1016/j.watres.2017.06.072}, abstractNote={Fat, oil and grease (FOG) blockages in sewer systems are a substantial problem in the United States. It has been estimated that over 50% of sewer overflows are a result of FOG blockages. In this work, a thorough laboratory study was undertaken to examine key variables that contribute to FOG deposit formation under controlled conditions. Physical and chemical properties and their interactions were evaluated and conditions that generated deposits that mimicked field FOG deposits were identified. It was found that 96 of the of 128 reaction conditions tested in the laboratory formed FOG deposits with similar physical and chemical characteristics as field FOG deposits. It was also found that FOG deposits can be created through fatty acid crystallization and not just saponification. Furthermore FOG deposits were found to be more complex than previously documented and contain free fatty acids, fatty acid metal salts, triacylglycerol's, diacylglycerol's and, monoacylglycerol's. Lastly it was found that FOG deposits that only contained saturated fatty acids were on average 2.1 times higher yield strength than deposits that contained unsaturated fatty acids.}, journal={WATER RESEARCH}, author={Gross, Martin A. and Jensen, Jeanette L. and Gracz, Hanna S. and Dancer, Jens and Keener, Kevin M.}, year={2017}, month={Oct}, pages={173–182} }
 @article{mohiti-asli_saha_murphy_gracz_pourdeyhimi_atala_loboa_2017, title={Ibuprofen loaded PLA nanofibrous scaffolds increase proliferation of human skin cells in vitro and promote healing of full thickness incision wounds in vivo}, volume={105}, ISSN={["1552-4981"]}, DOI={10.1002/jbm.b.33520}, abstractNote={This article presents successful incorporation of ibuprofen in polylactic acid (PLA) nanofibers to create scaffolds for the treatment of both acute and chronic wounds. Nanofibrous PLA scaffolds containing 10, 20, or 30 wt % ibuprofen were created and ibuprofen release profiles quantified. In vitro cytotoxicity to human epidermal keratinocytes (HEK) and human dermal fibroblasts (HDF) of the three scaffolds with varying ibuprofen concentrations were evaluated and compared to pure PLA nanofibrous scaffolds. Thereafter, scaffolds loaded with ibuprofen at the concentration that promoted human skin cell viability and proliferation (20 wt %) were evaluated in vivo in nude mice using a full thickness skin incision model to determine the ability of these scaffolds to promote skin regeneration and/or assist with scarless healing. Both acellular and HEK and HDF cell-seeded 20 wt % ibuprofen loaded nanofibrous bandages reduced wound contraction compared with wounds treated with Tegaderm™ and sterile gauze. Newly regenerated skin on wounds treated with cell-seeded 20 wt % ibuprofen bandages exhibited significantly greater blood vessel formation relative to acellular ibuprofen bandages. We have found that degradable anti-inflammatory scaffolds containing 20 wt % ibuprofen promote human skin cell viability and proliferation in vitro, reduce wound contraction in vivo, and when seeded with skin cells, also enhance new blood vessel formation. The approaches and results reported here hold promise for multiple skin tissue engineering and wound healing applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 327-339, 2017.}, number={2}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS}, author={Mohiti-Asli, M. and Saha, S. and Murphy, S. V. and Gracz, H. and Pourdeyhimi, B. and Atala, A. and Loboa, E. G.}, year={2017}, month={Feb}, pages={327–339} }
 @article{gurarslan_hardrict_roy_galvin_hill_gracz_sumerlin_genzer_tonelli_2015, title={Beyond Microstructures: Using the Kerr Effect to Characterize the Macrostructures of Synthetic Polymers}, volume={53}, ISSN={["1099-0488"]}, DOI={10.1002/polb.23598}, abstractNote={The macrostructures of synthetic polymers are essentially the complete molecular chain architectures, including the types and amounts of constituent short-range microstructures, such as the regio- and stereosequences of the inserted monomers, the amounts and sequences of monomers found in co-, ter-, and tetra-polymers, branching, inadvertent, and otherwise, etc. Currently, the best method for characterizing polymer microstructures uses high field, high resolution 13C-nuclear magnetic resonance (NMR) spectroscopy observed in solution. However, even 13C-NMR is incapable of determining the locations or positions of resident polymer microstructures, which are required to elucidate their complete macrostructures. The sequences of amino acid residues in proteins, or their primary structures, cannot be characterized by NMR or other short-range spectroscopic methods, but only by decoding the DNA used in their syntheses or, if available, X-ray analysis of their single crystals. Similarly, there are currently no experimental means to determine the sequences or locations of constituent microstructures along the chains of synthetic macromolecules. Thus, we are presently unable to determine their macrostructures. As protein tertiary and quaternary structures and their resulting ultimate functions are determined by their primary sequence of amino acids, so too are the behaviors and properties of synthetic polymers critically dependent on their macrostructures. We seek to raise the consciousness of both synthetic and physical polymer scientists and engineers to the importance of characterizing polymer macrostructures when attempting to develop structure–property relations. To help achieve this task, we suggest using the electrical birefringence or Kerr effects observed in their dilute solutions. The molar Kerr constants of polymer solutes contributing to the birefringence of their solutions, under the application of a strong electric field, are highly sensitive to both the types and locations of their constituent microstructures. As a consequence, we may begin to characterize the macrostructures of synthetic polymers by means of the Kerr effect. To simplify implementation of the Kerr effect to characterize polymer macrostructures, we suggest that NMR first be used to determine the types and amounts of constituent microstructures present. Subsequent comparison of observed Kerr effects with those predicted for different microstructural locations along the polymer chains can then be used to identify the most likely macrostructures. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 155–166}, number={3}, journal={JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS}, author={Gurarslan, Rana and Hardrict, Shauntrece and Roy, Debashish and Galvin, Casey and Hill, Megan R. and Gracz, Hanna and Sumerlin, Brent S. and Genzer, Jan and Tonelli, Alan}, year={2015}, month={Feb}, pages={155–166} }
 @article{d'antonio_deinema_kearns_frey_tanghe_perry_roy_gracz_rodriguez_d'antonio_2015, title={Structure-based approach to the identification of a novel group of selective glucosamine analogue inhibitors of Trypanosoma cruzi glucokinase}, volume={204}, number={2}, journal={Molecular and Biochemical Parasitology}, author={D'Antonio, E. L. and Deinema, M. S. and Kearns, S. P. and Frey, T. A. and Tanghe, S. and Perry, K. and Roy, T. A. and Gracz, H. S. and Rodriguez, A. and D'Antonio, J.}, year={2015}, pages={64–76} }
 @article{hurley-sanders_stoskopf_nelson_showers_law_gracz_levine_2015, title={Tissue extraction methods for metabolic profiling of a freshwater bivalve, Elliptio complanata}, volume={33}, ISSN={0740-2783 2162-2698}, url={http://dx.doi.org/10.4003/006.033.0209}, DOI={10.4003/006.033.0209}, abstractNote={Abstract: 
 Much is still unknown about why freshwater mussels (Unionidae) are particularly sensitive to environmental change. A better understanding of freshwater mussel metabolism is needed, and the field of environmental metabolomics holds the promise to inform these questions. A number of protocols exist for the extraction of metabolites for identification from animal tissues. As a first step in the application of environmental metabolomics to the study of freshwater mussels, we compared extraction protocols using an inorganic oxidizing acid (perchloric acid), an organic nitrile (acetonitrile), and a salt/water solution (Ringer's solution) to establish an uncomplicated, robust, repeatable and inexpensive tissue extraction protocol for freshwater mussel tissue. Perchloric acid resulted in notable extraction of energy-related nucleotides (AMP/ADP/ATP), yet had the lowest peak count of the three extraction methods and showed poor repeatability. Acetonitrile and Ringer's solution yielded metabolite extraction results similar to each other with Ringer's solution having the greatest number of peaks particularly in the 3.0–4.5 ppm sugar/amino acid range. Ringer's solution is simple to use, safe and consistent and bears consideration when selecting an extraction protocol for 1H nuclear magnetic resonance experiments.}, number={2}, journal={American Malacological Bulletin}, publisher={American Malacological Society}, author={Hurley-Sanders, J.L. and Stoskopf, M. and Nelson, S.A.C. and Showers, W. and Law, J.M. and Gracz, H.S. and Levine, J.F.}, year={2015}, pages={185–194} }
 @article{cruz_yelle_gracz_barlaz_2014, title={Chemical Changes during Anaerobic Decomposition of Hardwood, Softwood, and Old Newsprint under Mesophilic and Thermophilic Conditions}, volume={62}, ISSN={["1520-5118"]}, DOI={10.1021/jf501653h}, abstractNote={The anaerobic decomposition of plant biomass is an important aspect of global organic carbon cycling. While the anaerobic metabolism of cellulose and hemicelluloses to methane and carbon dioxide are well-understood, evidence for the initial stages of lignin decomposition is fragmentary. The objective of this study was to look for evidence of chemical transformations of lignin in woody tissues [hardwood (HW), softwood (SW), and old newsprint (ONP)] after anaerobic decomposition using Klason and acid-soluble lignin, CuO oxidation, and 2D NMR. Tests were conducted under mesophilic and thermophilic conditions, and lignin associations with structural carbohydrates are retained. For HW and ONP, the carbon losses could be attributed to cellulose and hemicelluloses, while carbon loss in SW was attributable to an uncharacterized fraction (e.g., extractives etc.). The 2D NMR and chemical degradation methods revealed slight reductions in β-O-4 linkages for HW and ONP, with no depolymerization of lignin in any substrate.}, number={27}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Cruz, Florentino B. and Yelle, Daniel J. and Gracz, Hanna S. and Barlaz, Morton A.}, year={2014}, month={Jul}, pages={6362–6374} }
 @article{achinivu_howard_li_gracz_henderson_2014, title={Lignin extraction from biomass with protic ionic liquids}, volume={16}, ISSN={["1463-9270"]}, DOI={10.1039/c3gc42306a}, abstractNote={A highly effective method has been developed for the simple extraction of lignin from lignocellulosic biomass using a potentially inexpensive protic ionic liquid (PIL). After the lignin-extraction step, the PIL is easily recovered using distillation leaving the separated lignin and cellulose-rich residues available for further processing. Biopolymer solubility tests indicate that increasing the xylan (i.e., hemicellulose) solubility in the PIL results in greater fiber disruption/penetration, which significantly enhances the effectiveness of the lignin extraction.}, number={3}, journal={GREEN CHEMISTRY}, author={Achinivu, Ezinne C. and Howard, Reagan M. and Li, Guoqing and Gracz, Hanna and Henderson, Wesley A.}, year={2014}, pages={1114–1119} }
 @article{hardrict_gurarslan_galvin_gracz_roy_sumerlin_genzer_tonelli_2013, title={Characterizing polymer macrostructures by identifying and locating microstructures along their chains with the kerr effect}, volume={51}, ISSN={["0887-6266"]}, DOI={10.1002/polb.23248}, abstractNote={In this brief report, we demonstrate that Kerr effect measurements, which determine the excess birefringence con- tributed 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 sty- rene (S) and p-bromostyrene (pBrS) units, but with two differ- ent block arrangements, that is, pBrS90-b-S120-b-pBrS90 (I) and S60-b-pBrS180-b-S60 (II), which are indistinguishable by NMR, we detected a dramatic difference in their molar Kerr constants (mK), in agreement with those previously estimated. Although similar in magnitude, their Kerr constants differ in sign, with mK(II) positive and mK(I) negative. In addition, S/pBrS random and gradient copolymers synthesized by reversible addition- fragmentation chain-transfer (RAFT) polymerization exhibit a heretofore unexpected enhanced enchainment of racemic (r) pBrS-pBrS diads. Comparison of their observed and calculated mKs suggests that the gradient S/pBrS copolymers possess an unanticipated additional gradient in stereosequence that paral- lels their comonomer gradient, that is, as the concentration of pBrs 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 macromole- cules, and not NMR, which is only sensitive to local polymer structural environments, but not to their locations on the co- polymer chains. Molar Kerr constants are characteristic of entire polymer chains and are highly sensitive to their constitu- ent 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. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 735-741}, number={9}, journal={JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS}, author={Hardrict, S. N. and Gurarslan, R. and Galvin, C. J. and Gracz, H. and Roy, D. and Sumerlin, B. S. and Genzer, J. and Tonelli, A. E.}, year={2013}, month={May}, pages={735–741} }
 @article{scholl_rabbi_lee_manson_s-gracz_marszalek_2013, title={Origin of Overstretching Transitions in Single-Stranded Nucleic Acids}, volume={111}, ISSN={["1079-7114"]}, DOI={10.1103/physrevlett.111.188302}, abstractNote={We combined single-molecule force spectroscopy with nuclear magnetic resonance measurements and molecular mechanics simulations to examine overstretching transitions in single-stranded nucleic acids. In single-stranded DNA and single-stranded RNA there is a low-force transition that involves unwinding of the helical structure, along with base unstacking. We determined that the high-force transition that occurs in polydeoxyadenylic acid single-stranded DNA is caused by the cooperative forced flipping of the dihedral angle formed between four atoms, O5'-C5'-C4'-C3' (γ torsion), in the nucleic acid backbone within the canonical B-type helix. The γ torsion also flips under force in A-type helices, where the helix is shorter and wider as compared to the B-type helix, but this transition is less cooperative than in the B type and does not generate a high-force plateau in the force spectrums of A-type helices. We find that a similar high-force transition can be induced in polyadenylic acid single-stranded RNA by urea, presumably due to disrupting the intramolecular hydrogen bonding in the backbone. We hypothesize that a pronounced high-force transition observed for B-type helices of double stranded DNA also involves a cooperative flip of the γ torsion. These observations suggest new fundamental relationships between the canonical structures of single-and double-stranded DNA and the mechanism of their molecular elasticity.}, number={18}, journal={PHYSICAL REVIEW LETTERS}, author={Scholl, Zackary N. and Rabbi, Mahir and Lee, David and Manson, Laura and S-Gracz, Hanna and Marszalek, Piotr E.}, year={2013}, month={Oct} }
 @article{franzen_sasan_sturgeon_lyon_battenburg_gracz_dumariah_ghiladi_2012, title={Nonphotochemical Base-Catalyzed Hydroxylation of 2,6-Dichloroquinone by H2O2Occurs by a Radical Mechanism}, volume={116}, ISSN={1520-6106 1520-5207}, url={http://dx.doi.org/10.1021/jp208536x}, DOI={10.1021/jp208536x}, abstractNote={Kinetic and structural studies have shown that peroxidases are capable of the oxidation of 2,4,6-trichlorophenol (2,4,6-TCP) to 2,6-dichloro-1,4-benzoquinone (2,6-DCQ). Further reactions of 2,6-DCQ in the presence of H(2)O(2) and OH(-) yield 2,6-dichloro-3-hydroxy-1,4-benzoquinone (2,6-DCQOH). The reactions of 2,6-DCQ have been monitored spectroscopically [UV-visible and electron spin resonance (ESR)] and chromatographically. The hydroxylation product, 2,6-DCQOH, has been observed by UV-visible and characterized structurally by (1)H and (13)C NMR spectroscopy. The results are consistent with a nonphotochemical base-catalyzed oxidation of 2,6-DCQ at pH > 7. Because H(2)O(2) is present in peroxidase reaction mixtures, there is also a potential role for the hydrogen peroxide anion (HOO(-)). However, in agreement with previous work, we observe that the nonphotochemical epoxidation by H(2)O(2) at pH < 7 is immeasurably slow. Both room-temperature ESR and rapid-freeze-quench ESR methods were used to establish that the dominant nonphotochemical mechanism involves formation of a semiquinone radical (base -catalyzed pathway), rather than epoxidation (direct attack by H(2)O(2) at low pH). Analysis of the kinetics using an Arrhenius model permits determination of the activation energy of hydroxylation (E(a) = 36 kJ/mol), which is significantly lower than the activation energy of the peroxidase-catalyzed oxidation of 2,4,6-TCP (E(a) = 56 kJ/mol). However, the reaction is second order in both 2,6-DCQ and OH(-) so that its rate becomes significant above 25 °C due to the increased rate of formation of 2,6-DCQ that feeds the second-order process. The peroxidase used in this study is the dehaloperoxidase-hemoglobin (DHP A) from Amphitrite ornata , which is used to study the effect of a catalyst on the reactions. The control experiments and precedents in studies of other peroxidases lead to the conclusion that hydroxylation will be observed following any process that leads to the formation of the 2,6-DCQ at pH > 7, regardless of the catalyst used in the 2,4,6-TCP oxidation reaction.}, number={5}, journal={The Journal of Physical Chemistry B}, publisher={American Chemical Society (ACS)}, author={Franzen, Stefan and Sasan, Koroush and Sturgeon, Bradley E. and Lyon, Blake J. and Battenburg, Benjamin J. and Gracz, Hanna and Dumariah, Rania and Ghiladi, Reza}, year={2012}, month={Jan}, pages={1666–1676} }
 @article{d’antonio_d’antonio_de serrano_gracz_thompson_ghiladi_bowden_franzen_2011, title={Functional Consequences of the Creation of an Asp-His-Fe Triad in a 3/3 Globin}, volume={50}, ISSN={0006-2960 1520-4995}, url={http://dx.doi.org/10.1021/bi201368u}, DOI={10.1021/bi201368u}, abstractNote={The proximal side of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata has been modified via site-directed mutagenesis of methionine 86 into aspartate (M86D) to introduce an Asp-His-Fe triad charge relay. X-ray crystallographic structure determination of the metcyano forms of M86D [Protein Data Bank (PDB) entry 3MYN ] and M86E (PDB entry 3MYM ) mutants reveal the structural origins of a stable catalytic triad in DHP A. A decrease in the rate of H(2)O(2) activation as well as a lowered reduction potential versus that of the wild-type enzyme was observed in M86D. One possible explanation for the significantly lower activity is an increased affinity for the distal histidine in binding to the heme Fe to form a bis-histidine adduct. Resonance Raman spectroscopy demonstrates a pH-dependent ligation by the distal histidine in M86D, which is indicative of an increased trans effect. At pH 5.0, the heme Fe is five-coordinate, and this structure resembles the wild-type DHP A resting state. However, at pH 7.0, the distal histidine appears to form a six-coordinate ferric bis-histidine (hemichrome) adduct. These observations can be explained by the effect of the increased positive charge on the heme Fe on the formation of a six-coordinate low-spin adduct, which inhibits the ligation and activation of H(2)O(2) as required for peroxidase activity. The results suggest that the proximal charge relay in peroxidases regulate the redox potential of the heme Fe but that the trans effect is a carefully balanced property that can both activate H(2)O(2) and attract ligation by the distal histidine. To understand the balance of forces that modulate peroxidase reactivity, we studied three M86 mutants, M86A, M86D, and M86E, by spectroelectrochemistry and nuclear magnetic resonance spectroscopy of (13)C- and (15)N-labeled cyanide adducts as probes of the redox potential and of the trans effect in the heme Fe, both of which can be correlated with the proximity of negative charge to the N(δ) hydrogen of the proximal histidine, consistent with an Asp-His-Fe charge relay observed in heme peroxidases.}, number={44}, journal={Biochemistry}, publisher={American Chemical Society (ACS)}, author={D’Antonio, Edward L. and D’Antonio, Jennifer and de Serrano, Vesna and Gracz, Hanna and Thompson, Matthew K. and Ghiladi, Reza A. and Bowden, Edmond F. and Franzen, Stefan}, year={2011}, month={Nov}, pages={9664–9680} }
 @article{feese_sadeghifar_gracz_argyropoulos_ghiladi_2011, title={Photobactericidal Porphyrin-Cellulose Nanocrystals: Synthesis, Characterization, and Antimicrobial Properties}, volume={12}, ISSN={1525-7797 1526-4602}, url={http://dx.doi.org/10.1021/bm200718s}, DOI={10.1021/bm200718s}, abstractNote={Adherence and survival of pathogenic bacteria on surfaces leading to concomitant transmission to new hosts significantly contributes to the proliferation of pathogens, which in turn considerably increases the threat to human health, particularly by antibiotic-resistant bacteria. Consequently, more research into effective surface disinfection and alternative materials (fabrics, plastics, or coatings) with antimicrobial and other bioactive characteristics is desirable. This report describes the synthesis and characterization of cellulose nanocrystals that were surface-modified with a cationic porphyrin. The porphyrin was appended onto the cellulose surface via the Cu(I)-catalyzed Huisgen-Meldal-Sharpless 1,3-dipolar cycloaddition having occurred between azide groups on the cellulosic surface and porphyrinic alkynes. The resulting, generally insoluble, crystalline material, CNC-Por (5), was characterized by infrared and diffusion (1)H NMR spectroscopies, gel permeation chromatography, and thermogravimetric analysis. Although only suspended, and not dissolved, in an aqueous system, CNC-Por (5) showed excellent efficacy toward the photodynamic inactivation of Mycobacterium smegmatis and Staphylococcus aureus , albeit only slight activity against Escherichia coli . The synthesis, properties, and activity of CNC-Por (5) described herein serve as a benchmark toward our overall objectives of developing novel, potent, bioactive, photobactericidal materials that are effective against a range of bacteria, with potential utilization in the health care and food preparation industries.}, number={10}, journal={Biomacromolecules}, publisher={American Chemical Society (ACS)}, author={Feese, Elke and Sadeghifar, Hasan and Gracz, Hanna S. and Argyropoulos, Dimitris S. and Ghiladi, Reza A.}, year={2011}, month={Oct}, pages={3528–3539} }
 @article{balakshin_capanema_gracz_chang_jameel_2011, title={Quantification of lignin-carbohydrate linkages with high-resolution NMR spectroscopy}, volume={233}, ISSN={["0032-0935"]}, DOI={10.1007/s00425-011-1359-2}, abstractNote={A quantitative approach to characterize lignin-carbohydrate complex (LCC) linkages using a combination of quantitative ¹³C NMR and HSQC 2D NMR techniques has been developed. Crude milled wood lignin (MWLc), LCC extracted from MWLc with acetic acid (LCC-AcOH) and cellulolytic enzyme lignin (CEL) preparations were isolated from loblolly pine (Pinus taeda) and white birch (Betula pendula) woods and characterized using this methodology on a routine 300 MHz NMR spectrometer and on a 950 MHz spectrometer equipped with a cryogenic probe. Structural variations in the pine and birch LCC preparations of different types (MWL, CEL and LCC-AcOH) were elucidated. The use of the high field NMR spectrometer equipped with the cryogenic probe resulted in a remarkable improvement in the resolution of the LCC signals and, therefore, is of primary importance for an accurate quantification of LCC linkages. The preparations investigated showed the presence of different amounts of benzyl ether, γ-ester and phenyl glycoside LCC bonds. Benzyl ester moieties were not detected. Pine LCC-AcOH and birch MWLc preparations were preferable for the analysis of phenyl glycoside and ester LCC linkages in pine and birch, correspondingly, whereas CEL preparations were the best to study benzyl ether LCC structures. The data obtained indicate that pinewood contains higher amounts of benzyl ether LCC linkages, but lower amounts of phenyl glycoside and γ-ester LCC moieties as compared to birch wood.}, number={6}, journal={PLANTA}, author={Balakshin, Mikhail and Capanema, Ewellyn and Gracz, Hanna and Chang, Hou-min and Jameel, Hasan}, year={2011}, month={Jun}, pages={1097–1110} }
 @article{szulc_bai_bielawski_mayroo_miller_gracz_hannun_bielawska_2010, title={Synthesis, NMR characterization and divergent biological actions of 2 '-hydroxy-ceramide/dihydroceramide stereoisomers in MCF7 cells}, volume={18}, ISSN={["1464-3391"]}, DOI={10.1016/j.bmc.2010.08.050}, abstractNote={A straightforward method for the simultaneous preparation of (2S,3R,2'R)- and (2S,3R,2'S)-2'-hydroxy-ceramides (2'-OHCer) from (2S,3R)-sphingosine acetonide precursors and racemic mixtures of 2-hydroxy fatty acids (2-OHFAs) is described. The obtained 2'-OH-C4-, -C6-, -C12-, -C16-Cer and 2'-OH-C6-dhCer pairs of diastereoisomers were characterized thoroughly by TLC, MS, NMR, and optical rotation. Dynamic and multidimensional NMR studies provided evidence that polar interfaces of 2'-OHCers are extended and more rigid than observed for the corresponding non-hydroxylated analogs. Stereospecific profile on growth suppression of MCF7 cells was observed for (2'R)- and (2'S)-2'-OH-C6-Cers and their dihydro analogs. The (2'R)-isomers were more active than the (2'S)-isomers (IC(50) ∼3 μM/8 μM and IC(50) ∼8 μM/12 μM, respectively), surpassing activity of the ordinary C6-Cer (IC(50) ∼12 μM) and C6-dhCer (IC(50) ∼38 μM). Neither isomer of 2'-OH-C6-Cers and 2'-OH-C6-dhCers was metabolized to their cellular long chain 2'-OH-homologs. Surprisingly, the most active (2'R)-isomers did not influence the levels of the cellular Cers nor dhCers. Contrary to this, the (2'S)-isomers generated cellular Cers and dhCers efficiently. In comparison, the ordinary C6-Cer and C6-dhCer also significantly increased the levels of their cellular long chain homologs. These peculiar anabolic responses and SAR data suggest that (2'R)-2'-OHCers/dhCers may interact with some distinct cellular regulatory targets in a specific and more effective manner than their non-hydroxylated analogs. Thus, stereoisomers of 2'-OHCers can be potentially utilized as novel molecular tools to study lipid-protein interactions, cell signaling phenomena and to understand the role of hydroxylated sphingolipids in cancer biology, pathogenesis and therapy.}, number={21}, journal={BIOORGANIC & MEDICINAL CHEMISTRY}, author={Szulc, Zdzislaw M. and Bai, Aiping and Bielawski, Jacek and Mayroo, Nalini and Miller, Doreen E. and Gracz, Hanna and Hannun, Yusuf A. and Bielawska, Alicja}, year={2010}, month={Nov}, pages={7565–7579} }
 @article{davis_gracz_vendeix_serrano_somasundaram_decatur_franzen_2009, title={Different Modes of Binding of Mono-, Di-, and Trihalogenated Phenols to the Hemoglobin Dehaloperoxidase from Amphitrite ornata}, volume={48}, ISSN={["0006-2960"]}, DOI={10.1021/bi801568s}, abstractNote={The hemoglobin dehaloperoxidase (DHP), found in the coelom of the terebellid polychaete Amphitrite ornata, is a dual-function protein that has the characteristics of both hemoglobins and peroxidases. In addition to oxygen transport function, DHP readily oxidizes halogenated phenols in the presence of hydrogen peroxide. The peroxidase activity of DHP is high relative to that of wild-type myoglobin or hemoglobin, but the most definitive difference in DHP is a well-defined substrate-binding site in the distal pocket, which was reported for 4-iodophenol in the X-ray crystal structure of DHP. The binding of 2,4,6-trihalogenated phenols is relevant since 2,4,6-tribromophenol is considered to be the native substrate and 2,4,6-trichlorophenol also gives high turnover rates in enzymatic studies. The most soluble trihalogenated phenol, 2,4,6-trifluorophenol, acts as a highly soluble structural analogue to the native substrate 2,4,6-tribromophenol. To improve our understanding of substrate binding, we compared the most soluble substrate analogues, 4-bromophenol, 2,4-dichlorophenol, and 2,4,6-trifluorophenol, using (1)H and (19)F NMR to probe substrate binding interactions in the active site of the low-spin metcyano adduct of DHP. Both mono- and dihalogenated phenols induced changes in resonances of the heme prosthetic group and an internal heme edge side chain, while (1)H NMR, (19)F NMR, and relaxation data for a 2,4,6-trihalogenated substrate indicate a mode of binding on the exterior of DHP. The differences in binding are correlated with differences in enzymatic activity for the substrates studied.}, number={10}, journal={BIOCHEMISTRY}, author={Davis, Michael F. and Gracz, Hanna and Vendeix, Franck A. P. and Serrano, Vesna and Somasundaram, Aswin and Decatur, Sean M. and Franzen, Stefan}, year={2009}, month={Mar}, pages={2164–2172} }
 @article{whang_vendeix_gracz_gadsby_tonelli_2008, title={NMR studies of the inclusion complex of cloprostenol sodium salt with beta-cyclodextrin in aqueous solution}, volume={25}, ISSN={["1573-904X"]}, DOI={10.1007/s11095-007-9493-z}, abstractNote={[[{:Label=>"PURPOSE", :NlmCategory=>"OBJECTIVE"}, "Cloprostenol sodium salt (referred as cloprostenol) may be used for the synchronization of estrous cycles in farm animal species. Cyclodextrins (CDs) have potential as drug delivery systems through the formation of inclusion complexes between CDs and drugs. This is the first study of the inclusion complex of cloprostenol with beta-cyclodextrin (beta-CD) in aqueous solution using NMR and 3D molecular dynamics simulations."], [{:Label=>"METHODS", :NlmCategory=>"METHODS"}, "1D proton NMR spectra of beta-CD, a complex of cloprostenol with beta-CD, and cloprostenol in D(2)O were assigned and confirmed. The cross relaxation interactions from ROESY were used as constraints for 3D molecular modeling studies."], [{:Label=>"RESULTS", :NlmCategory=>"RESULTS"}, "In the 2D ROESY of the complex, cross-peaks were observed between the aromatic protons of cloprostenol and protons of the beta-CD as well as between aliphatic protons and protons of the beta-CD. The stoichiometry of the complex was found that beta-CD forms a 1:1 inclusion complex with cloprostenol. The association constant K was 968 +/- 120 M(-1) at 298 K."], [{:Label=>"CONCLUSIONS", :NlmCategory=>"CONCLUSIONS"}, "Aromatic side and/or aliphatic side chains of the cloprostenol is included in the beta-CD while aliphatic side and/or aromatic side chains wraps around beta-CD, respectively. The molecular modeling also confirms that beta-CD forms a 1:1 inclusion complex with cloprostenol."]]}, number={5}, journal={PHARMACEUTICAL RESEARCH}, author={Whang, Hyun Suk and Vendeix, Franck A. P. and Gracz, Hanna S. and Gadsby, John and Tonelli, Alan}, year={2008}, month={May}, pages={1142–1149} }
 @article{kim_gracz_roberts_kiserow_2008, title={Spectroscopic analysis of poly(bisphenol A carbonate) using high resolution C-13 and H-1 NMR}, volume={49}, ISSN={["0032-3861"]}, DOI={10.1016/j.polymer.2007.11.046}, abstractNote={Quantitative structural and end-group analysis of poly(bisphenol A carbonate) (BPA-PC) was carried out and number average molecular weights (Mn) were determined using 125.76 MHz 13C and 500.13 MHz 1H nuclear magnetic resonance (NMR) spectroscopy. BPA-PC with a wide range of end-group ratios (0.26–2.83) and number average molecular weights (1500–9000 g/mol) was synthesized using melt transesterification by changing the initial monomer (bisphenol A and diphenyl carbonate) ratios and reaction conditions. Results of the NMR analysis for the melt-polymerized samples were compared with those of a commercial BPA-PC with a Mn of 16,000 g/mol. It was demonstrated that NMR spectroscopy is a very selective and accurate method not only for quantification of both phenolic and phenyl chain end-groups but also in the structural analysis of main chain groups. Extremely small concentrations of end-groups (∼0.02 per repeating unit) were analyzed. In addition, NMR spectroscopy was found to be an excellent tool for detecting residual monomer and the presence of the reaction byproduct (phenol). The molecular weights that were determined using NMR end-group quantification agreed well with the molecular weights measured by gel-permeation chromatography (GPC).}, number={2}, journal={POLYMER}, author={Kim, Jaehoon and Gracz, Hanna S. and Roberts, George W. and Kiserow, Douglas J.}, year={2008}, month={Jan}, pages={394–404} }
 @article{ke_humeniuk_s-gracz_marszalek_2007, title={Direct measurements of base stacking interactions in DNA by single-molecule atomic-force spectroscopy}, volume={99}, ISSN={["1079-7114"]}, DOI={10.1103/physrevlett.99.018302}, abstractNote={We investigate the elasticity of two types of single-stranded synthetic DNA homopolydeoxynucletides, poly(dA) and poly(dT), by AFM-based single-molecule force spectroscopy. We find that poly(dT) exhibits the expected entropic elasticity behavior, while poly(dA) unexpectedly displays two overstretching transitions in the force-extension relationship. We suggest that these transitions, which occur at approximately 23 pN and approximately 113 pN, directly capture, for the first time, the mechanical signature of base-stacking interactions among adenines in DNA, in the absence of base pairing.}, number={1}, journal={PHYSICAL REVIEW LETTERS}, author={Ke, Changhong and Humeniuk, Michael and S-Gracz, Hanna and Marszalek, Piotr E.}, year={2007}, month={Jul} }
 @article{uyar_hunt_gracz_tonelli_2006, title={Crystalline cyclodextrin inclusion compounds formed with aromatic guests: Guest-dependent stoichiometries and hydration-sensitive crystal structures}, volume={6}, ISSN={["1528-7505"]}, DOI={10.1021/cg050500+}, abstractNote={A series of solid inclusion complexes (ICs) containing the aromatic guests aniline, benzene, ethylbenzene, phenol, p-xylene, styrene, and toluene were formed with host γ-cyclodextrin (γ-CD). IC stoichiometry was observed to depend on the nature of the included aromatic guest. The molar ratio of styrene, aniline, and phenol guests to γ-CD host was ∼2:1 in their individual IC crystals, whereas ethylbenzene, p-xylene, and toluene guests formed ∼1:1 inclusion complexes with γ-CD. Thermogravimetric analysis showed that the thermal stabilities of these volatile aromatic guest molecules increased due to guest−host interactions once they were included in their γ-CD-ICs. X-ray diffraction (WAXD) observations performed on the aromatic guest−CD-IC crystals showed that all of them have channel-type crystalline structures. Moreover, it was observed that the presence of guest molecules inside the γ-CD cavities stabilized the channel structure of stacked γ-CDs. However, a solid-phase transition from tetragonal to hexago...}, number={5}, journal={CRYSTAL GROWTH & DESIGN}, author={Uyar, T and Hunt, MA and Gracz, HS and Tonelli, AE}, year={2006}, month={May}, pages={1113–1119} }
 @article{uyar_gracz_rusa_shin_el-shafei_tonelli_2006, title={Polymerization of styrene in gamma-cyclodextrin channels: Lightly rotaxanated polystyrenes with altered stereosequences}, volume={47}, ISSN={["0032-3861"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33748531256&partnerID=MN8TOARS}, DOI={10.1016/j.polymer.2006.07.054}, abstractNote={Modeling of polystyrene (PS) with various stereosequences in γ-cyclodextrin (γ-CD) channels has been conducted and it was found that only isotactic PS stereoisomers can fit into the γ-CD cavity. Thus, based on the modeling of stereoisomeric polystyrenes in narrow γ-CD channels, it was suggested that PSs with unusual microstructures might be produced via constrained polymerization of styrene monomer in its γ-CD-IC crystals. The in situ polymerization of styrene inside the narrow channels of its γ-CD-IC crystals suspended in aqueous media was performed. Alternatively, the solid-state polymerization of styrene/γ-CD-IC has also been conducted by exposure to γ-radiation. It was found that most host γ-CD molecules slip off during polymerization and the channel structure was not preserved. Consequently, much of the guest styrene monomer polymerizes outside of the host γ-CD channels, where the constrained environment is absent. Yet, a lightly rotaxanated structure has been obtained, where some threaded γ-CD molecules ∼15 wt% (∼1 γ-CD per 70 PS repeat units) are permanently entrapped along the PS chains after polymerization. 13C NMR spectra of PSs synthesized from styrene/γ-CD-IC and homogeneously in toluene show some differences, which are presumably due to variations in the stereosequences of PSs obtained from the partially constrained polymerization of styrene/γ-CD-IC.}, number={20}, journal={POLYMER}, author={Uyar, Tamer and Gracz, Hanna S. and Rusa, Mariana and Shin, I. Daniel and El-Shafei, Ahmed and Tonelli, Alan E.}, year={2006}, month={Sep}, pages={6948–6955} }
 @article{szulc_bielawski_gracz_gustilo_mayroo_hannun_obeid_bielawska_2006, title={Tailoring structure-function and targeting properties of ceramides by site-specific cationization}, volume={14}, ISSN={["1464-3391"]}, DOI={10.1016/j.bmc.2006.07.016}, abstractNote={In the course of our studies on compartment-specific lipid-mediated cell regulation, we identified an intimate connection between ceramides (Cers) and the mitochondria-dependent death-signaling pathways. Here, we report on a new class of cationic Cer mimics, dubbed ceramidoids, designed to act as organelle-targeted sphingolipids (SPLs), based on conjugates of Cer and dihydroceramide (dhCer) with pyridinium salts (CCPS and dhCCPS, respectively). Ceramidoids having the pyridinium salt unit (PSU) placed internally (alpha and gamma- CCPS) or as a tether (omega-CCPS) in the N-acyl moiety were prepared by N-acylation of sphingoid bases with different omega-bromo acids or pyridine carboxylic acid chlorides following capping with respective pyridines or alkyl bromides. Consistent with their design, these analogs, showed a significantly improved solubility in water, well-resolved NMR spectra in D(2)O, broadly modified hydrophobicity, fast cellular uptake, and higher anticancer activities in cells in comparison to uncharged counterparts. Structure-activity relationship (SAR) studies in MCF-7 breast carcinoma cells revealed that the location of the PSU and its overall chain length affected markedly the cytotoxic effects of these ceramidoids. All omega-CCPSs were more potent (IC(50/48 h): 0.6-8.0 microM) than their alpha/gamma-CCPS (IC(50/48 h): 8-20 microM) or D-erythro-C6-Cer (IC(50/48 h): 15 microM) analogs. omega-DhCCPSs were also moderately potent (IC(50/48 h): 2.5-12.5 microM). Long-chain omega-dhCCPSs were rapidly and efficiently oxidized in cells to the corresponding omega-CCPSs, as established by LC-MS analysis. CCPS analogs also induced acute changes in the levels and composition of endogenous Cers (upregulation of C16-, C14-, and C18-Cers, and downregulation of C24:0- and C24:1-Cers). These novel ceramidoids illustrate the feasibility of compartment-targeted lipids, and they should be useful in cell-based studies as well as potential novel therapeutics.}, number={21}, journal={BIOORGANIC & MEDICINAL CHEMISTRY}, author={Szulc, Zdzislaw M. and Bielawski, Jacek and Gracz, Hanna and Gustilo, Marietta and Mayroo, Nalini and Hannun, Yusuf A. and Obeid, Lina M. and Bielawska, Alicja}, year={2006}, month={Nov}, pages={7083–7104} }
 @article{ha_gracz_tonelli_hudson_2005, title={Structural study of irregular amino acid sequences in the heavy chain of Bombyx mori silk fibroin}, volume={6}, ISSN={["1526-4602"]}, DOI={10.1021/bm050294m}, abstractNote={Recently, genetic studies have revealed the entire amino acid sequence of Bombyx mori silk fibroin. It is known from X-ray diffraction studies that the beta-sheet crystalline structure (silk II) of fibroin is composed of hexaamino acid sequences of GAGAGS. However, in the heavy chain of B. mori silk fibroin, there are also present 11 irregular sequences, with about 31 amino acid residues (irregular GT approximately GT sequences). The structure and role of these irregular sequences have remained unknown. One of the most frequently appearing irregular sequences was synthesized and its 3-D solution structure was studied by high-resolution 2-D NMR techniques. The 3-D structure determined for this peptide shows that it makes a loop structure (distorted omega shape), which implies that the preceding backbone direction is changed by 180 degrees, i.e., reversed, by this sequence. This may facilitate the beta-sheet formation between the crystal-forming building blocks, GAGAGS/GY approximately GY sequences, in the fibroin heavy chain.}, number={5}, journal={BIOMACROMOLECULES}, author={Ha, SW and Gracz, HS and Tonelli, AE and Hudson, SM}, year={2005}, pages={2563–2569} }
 @article{wachowicz_wolak_gracz_stejskal_jurga_mccord_white_2004, title={Length scales which perturb chain packing in amorphous polymers}, volume={37}, ISSN={["1520-5835"]}, DOI={10.1021/ma049263u}, abstractNote={Direct spectroscopic probes of individual chain conformation and free volume are used to measure the increasing perturbation in the local glass-transition temperature of one polymer chain with decreasing length scale of mixing in binary polyolefin blends. Solid-state 2H and 129Xe NMR experiments reveal a compositional miscibility window in side-chain concentration for polyisobutylene (PIB)/poly(ethylene-co-butene) (PEB) blends. A combination of pulsed-field gradient and chemical shift data for xenon gas absorbed in these polymer blends indicates that the presence of polymer chains within a radius of ∼35 nm of a different chain structure will perturb the intermolecular packing contribution to the total conformational energy of that chain, thereby changing its Tg.}, number={12}, journal={MACROMOLECULES}, author={Wachowicz, M and Wolak, J and Gracz, H and Stejskal, EO and Jurga, S and McCord, EF and White, JL}, year={2004}, month={Jun}, pages={4573–4579} }
 @article{guenther_sit_gracz_dolan_townsend_liu_newman_agris_lommel_2004, title={Structural characterization of an intermolecular RNA-RNA interaction involved in the transcription regulation element of a bipartite plant virus}, volume={32}, ISSN={["1362-4962"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-3042761419&partnerID=MN8TOARS}, DOI={10.1093/nar/gkh585}, abstractNote={The 34-nucleotide trans-activator (TA) located within the RNA-2 of Red clover necrotic mosaic virus folds into a simple hairpin. The eight-nucleotide TA loop base pairs with eight complementary nucleotides in the TA binding sequence (TABS) of the capsid protein subgenomic promoter on RNA-1 and trans-activates subgenomic RNA synthesis. Short synthetic oligoribonucleotide mimics of the RNA-1 TABS and the RNA-2 TA form a weak 1:1 bimolecular complex in vitro with a K(a) of 5.3 x 10(4) M(-1). K(a) determination for a series of RNA-1 and RNA-2 mimic variants indicated optimum stability is obtained with seven-base complementarity. Thermal denaturation and NMR show that the RNA-1 TABS 8mers are weakly ordered in solution while RNA-2 TA oligomers form the predicted hairpin. NMR diffusion studies confirmed RNA-1 and RNA-2 oligomer complex formation in vitro. MC-Sym generated structural models suggest that the bimolecular complex is composed of two stacked helices, one being the stem of the RNA-2 TA hairpin and the other formed by the intermolecular base pairing between RNA-1 and RNA-2. The RCNMV TA structural model is similar to those for the Simian retrovirus frameshifting element and the Human immunodeficiency virus-1 dimerization kissing hairpins, suggesting a conservation of form and function.}, number={9}, journal={NUCLEIC ACIDS RESEARCH}, publisher={Oxford University Press (OUP)}, author={Guenther, RH and Sit, TL and Gracz, HS and Dolan, MA and Townsend, HL and Liu, GH and Newman, WH and Agris, PF and Lommel, SA}, year={2004}, month={May}, pages={2819–2828} }
 @article{chen_capanema_gracz_2003, title={Comparative studies on the delignification of pine kraft-anthraquinone pulp with hydrogen peroxide by binucleus Mn(IV) complex catalysis}, volume={51}, ISSN={["0021-8561"]}, DOI={10.1021/jf034507f}, abstractNote={Pine kraft-anthraquinone (kraft-AQ) pulp was bleached in alkaline solution with hydrogen peroxide catalyzed by either [L(1)Mn(IV)(micro-O)(3)Mn(IV)L(1)](PF(6))(2)] (C1) or [LMn(IV)(2)(micro-O)(3)] (ClO(4))(2) (C2) at 60 and 80 degrees C for 120 min with a catalyst charge of 10 ppm on pulp. The resulting bleached pulp was hydrolyzed with cellulase to obtain insoluble and soluble residual lignins. The alkaline bleaching effluents were acidified to precipitate alkaline-soluble lignins. These lignin preparations were then characterized by 2D heteronuclear multiple-quantum coherence (HMQC) NMR spectroscopic techniques. The results showed that biphenyl (5-5) and stilbene structures of the residual lignin in the pulp are preferentially degraded in both the C1- and C2-catalyzed bleachings, whereas beta-O-4, beta-5, and beta-beta structures undergo degradation to a lesser extent. In both cases, the degradation of the residual lignin increased with the increase in reaction temperature from 60 to 80 degrees C. Thus, the result of C1-catalyzed delignification is not in agreement with the observed decrease in the disappearance rate for substrates in the C1-catalyzed oxidation of lignin model compounds with hydrogen peroxide when the reaction temperature is increased from 60 to 80 degrees C. In addition, the resulting residual lignins in the C2-catalyzed bleaching at 80 degrees C are less degraded than the corresponding lignins in the C1-catalyzed bleaching at both 60 and 80 degrees C. Thus, C1 is more effective than C2 as catalyst in the binucleus Mn(IV) complex-catalyzed bleaching of pine kraft-AQ pulp with hydrogen peroxide.}, number={21}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Chen, CL and Capanema, EA and Gracz, HS}, year={2003}, month={Oct}, pages={6223–6232} }
 @article{balakshin_capanema_chen_gracz_2003, title={Elucidation of the structures of residual and dissolved pine kraft lignins using an HMQC NMR technique}, volume={51}, ISSN={["1520-5118"]}, DOI={10.1021/jf034372d}, abstractNote={Comparative studies on the structures of residual and dissolved lignins isolated from pine kraft pulp and pulping liquor have been undertaken using the (1)H-(13)C HMQC NMR technique, GPC, and sugar analysis to elucidate the reaction mechanisms in kraft pulping and the lignin reactivity. A modified procedure for the isolation of enzymatic residual lignins has resulted in an appreciable decrease in protein contaminants in the residual lignin preparations (N content < 0.2%). The very high dispersion of HMQC spectra allows identification of different lignin moieties, which signals appear overlapped in 1D (13)C NMR spectra. Elucidation of the role of condensation reactions indicates that an increase in the degree of lignin condensation during pulping results from accumulation of original condensed lignin moieties rather than from the formation of new alkyl-aryl structures. Among aryl-vinyl type moieties, only stilbene structures are accumulated in lignin in appreciable amounts. Benzyl ether lignin-carbohydrate bonds involving primary hydroxyl groups of carbohydrates have been detected in residual and dissolved lignin preparations. Structures of the alpha-hydroxyacid type have been postulated to be among the important lignin degradation products in kraft pulping. The effect of the isolation method on the lignin structure and differences between the residual and dissolved lignins are discussed.}, number={21}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Balakshin, MY and Capanema, EA and Chen, CL and Gracz, HS}, year={2003}, month={Oct}, pages={6116–6127} }
 @article{wolak_jia_gracz_stejskal_white_wachowicz_jurga_2003, title={Polyolefin miscibility: Solid-state NMR investigation of phase behavior in saturated hydrocarbon blends}, volume={36}, ISSN={["0024-9297"]}, DOI={10.1021/ma0301449}, abstractNote={Chain-level mixing in polyolefins is investigated for blends of polyisobutylene (PIB) and polyethylene-co-1-butene (PEB). Previous reports suggest that PIB exhibits unusual mixing behavior in certain saturated blends relative to other polyolefins, even though it is immiscible with most. Variable-temperature 1H, 2H, 13C, and 129Xe NMR experiments are used to characterize local PIB chain dynamics in blends with PEB in which the concentration of 1-butene comonomer units is 23 or 66 wt %. Results from 1D and 2D solid-state 13C exchange experiments, 1H relaxation measurements, and 2H line shape analysis indicate that local conformational dynamics of the PIB CH2 group in the polymer backbone increase significantly in blends with PEB copolymers containing 66 wt % butene comonomer (PEB-66). Even though the PEB-66 is a higher Tg polymer than PIB, PIB exhibits a lower effective Tg when the blend is formed relative to its pure state. Similar perturbations are not observed in the PIB/PEB-23 blend, indicating that thi...}, number={13}, journal={MACROMOLECULES}, author={Wolak, J and Jia, X and Gracz, H and Stejskal, EO and White, JL and Wachowicz, M and Jurga, S}, year={2003}, month={Jul}, pages={4844–4850} }
 @article{chen_capanema_gracz_2003, title={Reaction mechanisms in delignification of pine Kraft-AQ pulp with hydrogen peroxide using Mn(IV)-Me4DTNE as catalyst}, volume={51}, ISSN={["0021-8561"]}, DOI={10.1021/jf020992n}, abstractNote={Pine Kraft-AQ pulp was bleached with hydrogen peroxide catalyzed by [LMn(IV)(2) (mu-O)(3)](ClO(4))(2) at 80 degrees C for 120 min under optimum reaction conditions. The resulting bleached pulp was hydrolyzed with cellulase to obtain insoluble and soluble residual lignins. The alkaline effluent from the bleaching was acidified to precipitate alkaline soluble lignin. These lignin preparations were purified, and then analyzed by 2D HMQC NMR spectroscopic techniques. The results showed that biphenyl (5-5) and stilbene structures are preferentially degraded in the bleaching process, while beta-O-4, beta-5, and beta-beta structures undergo degradation only to a lesser extent. This implies that hydrogen peroxide bleaching using the catalyst is more effective in delignification of softwood pulps than hardwood pulps. The possible reaction mechanisms for the delignification of residual lignin in the pine Kraft-AQ pulp in the bleaching process are discussed on the basis of the 2D HMQC NMR spectroscopic data and the model compound experiments.}, number={7}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Chen, CL and Capanema, EA and Gracz, HS}, year={2003}, month={Mar}, pages={1932–1941} }
 @article{mitchell_alejos-gonzalez_gracz_danehower_daub_chilton_2003, title={Xanosporic acid, an intermediate in bacterial degradation of the fungal phototoxin cercosporin}, volume={62}, ISSN={["0031-9422"]}, DOI={10.1016/S0031-9422(02)00517-4}, abstractNote={The red fungal perylenequinone phototoxin cercosporin is oxidized by Xanthomonas campestris pv zinniae to a non-toxic, unstable green metabolite xanosporic acid, identified via its lactone as 1,12-bis(2'R-hydroxypropyl)-4,9-dihydroxy-6,7-methylenedioxy-11-methoxy-3-oxaperylen-10H-10-one-2-carboxylic acid. Xanosporolactone was isolated in approximately 2:1 ratio of M:P atropisomers.}, number={5}, journal={PHYTOCHEMISTRY}, author={Mitchell, TK and Alejos-Gonzalez, F and Gracz, HS and Danehower, DA and Daub, ME and Chilton, WS}, year={2003}, month={Mar}, pages={723–732} }
 @article{ghatnekar_gracz_smoak_2002, title={C-13-NMR study of hypoglycemia-induced glycolytic changes in embryonic mouse heart}, volume={66}, ISSN={["0040-3709"]}, DOI={10.1002/tera.10103}, abstractNote={BACKGROUND
Glucose metabolites can be detected in embryonic mouse tissues using 13C-NMR spectroscopy. The advantage of this method is in its chemical specificity and the ability to follow metabolic changes.


METHODS
In this study, CD-1 mice were mated and embryos excised on gestational day (GD) 10.5 (plug = GD 0.5). Hearts were isolated and cultured in 150 mg/dl glucose (normoglycemic medium) or 40 mg/dl glucose (hypoglycemic medium) for 6 hr. 13C-labeled glucose comprised 62%-64% of total glucose in the culture medium. Pre- and postculture media were treated with deuterated water (D2O), and 13C spectra were obtained using a Bruker Avance 500 MHz spectrometer operating at 11.744 tesla (125.7 MHz for 13C). NMR spectra demonstrated resonances for 13C-glucose in preculture normoglycemic and hypoglycemic media. Postculture spectra for normoglycemic and hypoglycemic media demonstrated 13C-glucose signals as well as a signal for 13C-lactate. Area under the curve (AUC) was measured for the [1-(13)C-glucose] resonance from preculture media and the [3-(13)C-lactate] resonance from postculture media. The ratios of AUC for postculture [3-(13)C-lactate] to preculture [1-(13)C-glucose] were calculated and found to be higher in hypoglycemic than in normoglycemic media.


RESULTS
Our results confirm earlier findings using radiolabeled substrates and suggest that 13C-NMR spectroscopy can be used to study glucose metabolism in isolated embryonic hearts exposed to hypoglycemia.


CONCLUSIONS
NMR effectively measures glucose and its metabolite, lactate, in the same spectrum and thus determines metabolic flux in the isolated embryonic heart after exposure to hypoglycemia and normoglycemia. This method could evaluate glucose metabolism in embryonic tissues following other teratogenic exposures.}, number={5}, journal={TERATOLOGY}, author={Ghatnekar, GS and Gracz, HS and Smoak, IW}, year={2002}, month={Nov}, pages={267–272} }
 @article{merkel_toy_andrady_gracz_stejskal_2002, title={Investigation of Enhanced Free Volume in Nanosilica-Filled Poly(1-trimethylsilyl-1-propyne) by 129Xe NMR Spectroscopy}, volume={36}, ISSN={0024-9297 1520-5835}, url={http://dx.doi.org/10.1021/ma0256690}, DOI={10.1021/ma0256690}, abstractNote={The gas permeability of poly[1-(trimethylsilyl)-1-propyne] (PTMSP) containing nanoparticulate fumed silica increases with increasing filler content. This unusual phenomenon is explored using 129Xe NMR spectroscopy to examine the effect of filler on the free volume of the PTMSP host matrix. The 129Xe NMR chemical shift decreases regularly with increasing fumed silica concentration, consistent with an increase in the average size of free volume elements or cavities through which molecular transport can occur. A relationship between the chemical shift and gas permeability in the filled polymer is reported.}, number={2}, journal={Macromolecules}, publisher={American Chemical Society (ACS)}, author={Merkel, T. C. and Toy, L. G. and Andrady, A. L. and Gracz, H. and Stejskal, E. O.}, year={2002}, month={Dec}, pages={353–358} }
 @article{balakshin_capanema_chen_gratzl_kirkman_gracz_2001, title={Biobleaching of pulp with dioxygen in the laccase-mediator system - reaction mechanisms for degradation of residual lignin}, volume={13}, ISSN={["1873-3158"]}, DOI={10.1016/S1381-1177(00)00225-3}, abstractNote={Pine Kraft-AQ pulp was biobleached with pressurized dioxygen at 40°C in laccase-mediator system (LMS), i.e. in acetate buffer (pH 4.5) containing Coriolus-laccase and 1-hydroxy-benzotriazole (HOBT), the latter being as a mediator. The LMS-treatment was followed by alkaline extraction (E) under standard conditions. The structures of the residual lignins before and after the biobleaching did not differ appreciably. This indicates that only a part of the residual lignin in the pulp undergoes oxidative degradation in the LMS treatment. In contrast, the treatment resulted in strong changes in the structure of the lignin isolated from E-effluents. The 2D HMQC (1H13C correlation) spectra showed the disappearance of β-O-4′, β-β′ and β-5′ bonds in the structure of the alkaline soluble lignin (ASL) from E-effluents, which are present in the 2D spectrum of the original residual lignin (RKL). In addition, the spectra exhibited new signals that are assigned to ArCOOH in biphenyl (5-5′) moieties. This implies that oxidative cleavage of side chains plays an important role in the delignification of pulp. The NMR studies also indicated that intensive degradation of aromatic ring has occurred in the biobleaching. However, premethylation of neither benzyl alcohol nor phenolic hydroxyl groups of the residual lignin in pulp before the biobleaching affected the rate of delignification. The latter indicates that phenolic moieties participate not only in oxidative degradation but also dehydrogenative polymerization reactions in the biobleaching. This is consistent with an appreciable increase in the proportion of fractions with higher molecular mass in lignin isolated from E-effluents.}, number={1-3}, journal={JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC}, author={Balakshin, M and Capanema, E and Chen, CL and Gratzl, J and Kirkman, A and Gracz, H}, year={2001}, month={Apr}, pages={1–16} }
 @article{capanema_balakshin_chen_gratzl_gracz_2001, title={Structural analysis of residual and technical lignins by H-1-C-13 correlation 2D NMR-spectroscopy}, volume={55}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2001.050}, abstractNote={Summary Structural analysis was conducted on residual lignin from pine Kraft AQ pulp, Eucalyptus Kraft lignin from Eucalyptus globulus and Repap Organosolv lignin by 2D 13C-1H correlation NMR spectroscopic techniques such as HMQC sequence. These lignins contain a rather wide variety of saturated aliphatic groups. The HMQC NMR spectra of the lignins do not verify the presence of diarylmethane moieties in any lignin investigated. The type and amount of other condensed structures depend on the nature of lignin preparation. All the lignins investigated still contained β-O-4′, pino- and syringayresinol (β-β′) and phenylcoumarane (β-5′) structures. Stilbene structures were also identified. Vinyl ether structures were present only in Eucalyptus Kraft lignin. All the lignins contain α-carbonyl groups conjugated to aromatic moieties as terminal side chains rather than involving β-O-4′ structures. No coniferyl alcohol and coniferyl aldehyde type structures are detected in the lignins after pulping. The spectra of kraft lignins show some new signals, the origin of which is discussed.}, number={3}, journal={HOLZFORSCHUNG}, author={Capanema, EA and Balakshin, MY and Chen, CL and Gratzl, JS and Gracz, H}, year={2001}, pages={302–308} }
 @article{burns_burroughs_gracz_pritchard_brozena_willoughby_khan, title={Cyclodextrin facilitated electrospun chitosan nanofibers}, volume={5}, number={10}, journal={RSC Advances}, author={Burns, N. A. and Burroughs, M. C. and Gracz, H. and Pritchard, C. Q. and Brozena, A. H. and Willoughby, J. and Khan, S. A.}, pages={7131–7137} }