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https://www.readbyqxmd.com/read/28937766/approach-toward-the-understanding-of-coupling-mechanism-for-edc-reagent-in-solvent-free-mechanosynthesis
#1
Aneta Wróblewska, Piotr Paluch, Ewelina Wielgus, Grzegorz Bujacz, Marta K Dudek, Marek J Potrzebowski
A unique approach in mechanosynthesis, joining solid-state NMR spectroscopy, X-ray crystallography, and theoretical calculations, is employed for the first time to study the mechanism of the formation of the C-N amide bond using EDC·HCl as a coupling reagent. It has been proved that EDC·HCl, which in the crystal lattice exists exclusively in the cyclic form (X-ray data), easily undergoes transformation to a pseudocyclic stable intermediate in reaction with carboxylic acid forming a low-melt phase (differential scanning calorimetry, solid-state NMR)...
September 22, 2017: Organic Letters
https://www.readbyqxmd.com/read/28937226/diblock-terpolymers-are-tunable-and-ph-responsive-vehicles-to-increase-hydrophobic-drug-solubility-for-oral-administration
#2
Swapnil Tale, Anatolii A Purchel, Molly C Dalsin, Theresa M Reineke
Synthetic polymers offer tunable platforms to create new oral drug delivery vehicles (excipients) to increase solubility, supersaturation maintenance, and bioavailability of poorly aqueous soluble pharmaceutical candidates. Five well-defined diblock terpolymers were synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) and consist of a first block of either poly(ethylene-alt-propylene) (PEP), poly(N-isopropylacrylamide) (PNIPAm), or poly(N,N-diethylaminoethyl methacrylate) (PDEAEMA) and a second hydrophilic block consisting of a gradient copolymer of N,N-dimethylacrylamide (DMA) and 2-methacrylamidotrehalose (MAT)...
September 22, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28936873/biochemical-characterization-of-arsi-a-novel-c-as-lyase-for-degradation-of-environmental-organoarsenicals
#3
Shashank S Pawitwar, Venkadesh S Nadar, Ashoka Kandegedara, Timothy L Stemmler, Barry P Rosen, Masafumi Yoshinaga
Organoarsenicals such as the methylarsenical methylarsenate (MAs(V)) and aromatic arsenicals including roxarsone (4-hydroxy-3-nitrobenzenearsenate or Rox(V)) have been extensively used as an herbicide and growth enhancers in animal husbandry, respectively. They undergo environmental degradation to more toxic inorganic arsenite (As(III)) that contaminates crops and drinking water. We previously identified a bacterial gene (arsI) responsible for aerobic demethylation of methylarsenite (MAs(III)). The gene product, ArsI, is an Fe(II)-dependent extradiol dioxygenase that cleaves the carbon-arsenic (C-As) bond in MAs(III) and in trivalent aromatic arsenicals...
September 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28936712/early-goal-directed-nutrition-versus-standard-of-care-in-adult-intensive-care-patients-the-single-centre-randomised-outcome-assessor-blinded-eat-icu-trial
#4
Matilde Jo Allingstrup, Jens Kondrup, Jørgen Wiis, Casper Claudius, Ulf Gøttrup Pedersen, Rikke Hein-Rasmussen, Mads Rye Bjerregaard, Morten Steensen, Tom Hartvig Jensen, Theis Lange, Martin Bruun Madsen, Morten Hylander Møller, Anders Perner
PURPOSE: We assessed the effects of early goal-directed nutrition (EGDN) vs. standard nutritional care in adult intensive care unit (ICU) patients. METHODS: We randomised acutely admitted, mechanically ventilated ICU patients expected to stay longer than 3 days in the ICU. In the EGDN group we estimated nutritional requirements by indirect calorimetry and 24-h urinary urea aiming at covering 100% of requirements from the first full trial day using enteral and parenteral nutrition...
September 22, 2017: Intensive Care Medicine
https://www.readbyqxmd.com/read/28936510/low-temperature-and-high-pressure-phases-of-a-room-temperature-ionic-liquid-and-polyiodides-1-methyl-3-propylimidazolium-iodide
#5
Hiroshi Abe, Hiroaki Kishimura, Mayumi Takaku, Mai Watanabe, Nozomu Hamaya
Using simultaneous small-angle X-ray scattering (SAXS) combined with differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) combined with DSC measurements, low-temperature (LT) solid phases of a room-temperature ionic liquid (RTIL) and its mixtures were examined at ambient pressure. The considered RTIL was 1-methyl-3-propylimidazolium iodide ([C3mim][I]), and the mixtures could be expressed as [C3mim][Im]. Under high-pressure (HP), the crystallization of pure [C3mim][I] was suppressed, as a LT-amorphous form of pure [C3mim][I] was formed...
September 22, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28936355/theoretical-and-experimental-study-of-the-antifreeze-protein-afp752-trehalose-and-dimethyl-sulfoxide-cryoprotection-mechanism-correlation-with-cryopreserved-cell-viability
#6
Irena Kratochvílová, Martin Golan, Karel Pomeisl, Jan Richter, Silvia Sedláková, Jakub Šebera, Júlia Mičová, Martin Falk, Iva Falková, David Řeha, K Wade Elliott, Krisztina Varga, Shelby E Follett, Daniel Šimek
In this work the physico-chemical properties of selected cryoprotectants (antifreeze protein TrxA-AFP752, trehalose and dimethyl sulfoxide) were correlated with their impact on the constitution of ice and influence on frozen/thawed cell viability. The freezing processes and states of investigated materials solutions were described and explained from a fundamental point of view using ab-initio modelling (molecular dynamics, DFT), Raman spectroscopy, Differential Scanning Calorimetry and X-Ray Diffraction. For the first time, in this work we correlated the microscopic view (modelling) with the description of the frozen solution states and put these results in the context of human skin fibroblast viability after freezing and thawing...
2017: RSC Advances
https://www.readbyqxmd.com/read/28935965/aromatic-side-chain-conformational-switch-on-the-surface-of-the-rna-recognition-motif-enables-rna-discrimination
#7
Nana Diarra Dit Konté, Miroslav Krepl, Fred F Damberger, Nina Ripin, Olivier Duss, Jiří Šponer, Frédéric H-T Allain
The cyclooxygenase-2 is a pro-inflammatory and cancer marker, whose mRNA stability and translation is regulated by the CUG-binding protein 2 interacting with AU-rich sequences in the 3' untranslated region. Here, we present the solution NMR structure of CUG-binding protein 2 RRM3 in complex with 5'-UUUAA-3' originating from the COX-2 3'-UTR. We show that RRM3 uses the same binding surface and protein moieties to interact with AU- and UG-rich RNA motifs, binding with low and high affinity, respectively. Using NMR spectroscopy, isothermal titration calorimetry and molecular dynamics simulations, we demonstrate that distinct sub-states characterized by different aromatic side-chain conformations at the RNA-binding surface allow for high- or low-affinity binding with functional implications...
September 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28935829/contribution-of-structural-brain-phenotypes-to-the-variance-in-resting-energy-expenditure-in-healthy-caucasian-subjects
#8
Corinna Geisler, Mark Hübers, Oliver Granert, Manfred James Muller
BACKGROUND: Brain gray (GM) and white matter (WM) volumes are related to weight changes. The impact of structural variations in GM and WM on the variance in resting energy expenditure (REE) and the REE on fat free mass (FFM) association is unknown. The aim of this study was to address this in healthy Caucasian subjects. METHODS: Cross-sectional data analysis of 493 healthy Caucasian subjects (age range 6 to 80 years; three age groups) with comprehensive information on FFM, organ and tissue masses and detailed brain composition as assessed by whole body magnetic resonance imaging (MRI) and REE (assessed by indirect calorimetry)...
September 21, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28935607/s-glutathionylation-of-glyceraldehyde-3-phosphate-dehydrogenase-induces-formation-of-c150-c154-intrasubunit-disulfide-bond-in-the-active-site-of-the-enzyme
#9
K V Barinova, M V Serebryakova, V I Muronetz, E V Schmalhausen
BACKGROUND: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a glycolytic protein involved in numerous non-glycolytic functions. S-glutathionylated GAPDH was revealed in plant and animal tissues. The role of GAPDH S-glutathionylation is not fully understood. METHODS: Rabbit muscle GAPDH was S-glutathionylated in the presence of H2O2 and reduced glutathione (GSH). The modified protein was assayed by MALDI-MS analysis, differential scanning calorimetry, dynamic light scattering, and ultracentrifugation...
September 18, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28934354/synthesis-of-irregular-graphene-oxide-tubes-using-green-chemistry-and-their-potential-use-as-reinforcement-materials-for-biomedical-applications
#10
Ángel Serrano-Aroca, Sanjukta Deb
Micrometer length tubes of graphene oxide (GO) with irregular form were synthesised following facile and green metal complexation reactions. These materials were obtained by crosslinking of GO with calcium, zinc or strontium chlorides at three different temperatures (24, 34 and 55°C) using distilled water as solvent for the compounds and following a remarkably simple and low-cost synthetic method, which employs no hazardous substances and is conducted without consumption of thermal or sonic energy. These irregular continuous GO networks showed a very particular interconnected structure by Field Emission Scanning Electron Microscopy with Energy-Disperse X-Ray Spectroscopy for elemental analysis and High-resolution Transmission Electron Microscopy with Scanning Transmission Electron Microscope Dark Field Imaging, and were analysed by Raman Spectroscopy...
2017: PloS One
https://www.readbyqxmd.com/read/28934147/effects-of-precipitant-and-ph-on-coprecipitation-of-nanosized-co-cr-v-alloy-powders
#11
Xiaoyu Chen, Yongxia Li, Lan Huang, Dan Zou, Enxi Wu, Yanjun Liu, Yuanyan Xie, Rui Yao, Songyi Liao, Guangrong Wang, Feng Zheng
Nanosized Co-Cr-V alloy powders were synthesized via coprecipitation method. Effects of precipitants ((NH₄)₂C₂O₄·H₂O and Na₂CO₃) and pH were investigated by X-ray diffraction (XRD), Zeta potential analyzer, thermogravimetry-differential scanning calorimetry (TG-DSC), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and scanning electron microscopy (SEM). Co-Cr-V alloy powders were consisted of major face-centered cubic Co (fcc Co) and minor hexagonal close-packed Co (hcp Co)...
September 21, 2017: Materials
https://www.readbyqxmd.com/read/28933861/differential-effect-of-bilayer-thickness-on-sticholysin-activity
#12
Juan Palacios Ortega, Sara Garcia-Linares, Esperanza Rivera-de-Torre, Jose G Gavilanes, Alvaro Martinez-Del-Pozo, J Peter Slotte
In this study, we examined the influence of bilayer thickness on the activity of the actinoporin toxins sticholysin I and II (StnI and StnII) at 25 °C. Bilayer thickness was varied using di-monounsaturated phosphatidylcholine (PC) analogs (with 14:1, 16:1, 18:1, 20:1, and 22:1 acyl chains). In addition, N-14:0-sphingomyelin (SM) was always included because StnI and StnII are SM specific. Cholesterol was also incorporated as indicated. In cholesterol-free large unilamellar vesicles (LUV) the PC:SM molar ratio was 4:1, and when cholesterol was included, the complete molar ratio was 4:1:0...
September 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28933744/energy-and-protein-in-critically-ill-patients-with-aki-a-prospective-multicenter-observational-study-using-indirect-calorimetry-and-protein-catabolic-rate
#13
Alice Sabatino, Miriam Theilla, Moran Hellerman, Pierre Singer, Umberto Maggiore, Maria Barbagallo, Giuseppe Regolisti, Enrico Fiaccadori
The optimal nutritional support in Acute Kidney Injury (AKI) still remains an open issue. The present study was aimed at evaluating the validity of conventional predictive formulas for the calculation of both energy expenditure and protein needs in critically ill patients with AKI. A prospective, multicenter, observational study was conducted on adult patients hospitalized with AKI in three different intensive care units (ICU). Nutrient needs were estimated by different methods: the Guidelines of the European Society of Parenteral and Enteral Nutrition (ESPEN) for both calories and proteins, the Harris-Benedict equation, the Penn-State and Faisy-Fagon equations for energy...
July 26, 2017: Nutrients
https://www.readbyqxmd.com/read/28933548/investigation-of-structure-and-crystallization-behavior-of-poly-butylene-succinate-by-fourier-transform-infrared-spectroscopy
#14
Shu-Fang Yao, Xiao-Tong Chen, Hai-Mu Ye
The detailed structure and crystallization behavior of poly(butylene succinate) (PBS) have been investigated by Fourier transform infrared (FTIR) and other methods systematically. For the first time, we confirmed that the C=O stretching modes of PBS can respond to three distinguish absorption bands in the FTIR spectrum, at around 1736, 1720 and 1714 cm-1 respectively. The 1736 cm-1 band is adopted as the stretching mode of C=O groups in free amorphous fraction (MAF); the 1714 cm-1 band which is relevant to more stable structure, displays more anisotropic in polarized FTIR spectra, and has been confirmed as stretching vibrations of hydrogen-bonded C=O groups in the crystalline phase...
September 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28933536/a-bimetallic-silver-neodymium-theranostic-nanoparticle-with-multimodal-nir-mri-ct-imaging-and-combined-chemo-photothermal-therapy
#15
Sandeep K Mishra, S Kannan
An engineered metallic nanostructure is an excellent candidate for "theranosis" of cancer, having intrinsic properties of multimodal imaging and therapy. Toward this target, the development of silver-neodymium bimetallic nanoparticles (Ag-Nd BNPs) via microwave-assisted polyol synthesis is presented. The resultant Ag-Nd BNPs exhibit good monodispersity with average size of 10 nm, fluorescence in the near-infrared (NIR) region, and magnetic properties. The Ag-Nd BNPs also validate MRI, CT, and NIR trimodal imaging ability and enunciate valuable temperature response upon irradiation under a NIR laser...
September 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28932695/disequilibrium-calorimetry-for-determination-of-ultrasonic-power-in-sonochemistry
#16
Mario Plattes, Christian Köhler, Tom Gallé
The two most characteristic properties of an ultrasonic wave are the frequency and the power. It is therefore important to determine the power in a given reactor. This can be done by calorimetry, i.e. by measuring the temperature rise in the vessel during sonication starting at thermal equilibrium with the surroundings (classic calorimetry) [1-3]. However, the classic ultrasonic calorimetry has drawbacks. In particular it is difficult to evaluate the temperature rise at thermal equilibrium, because the relevant initial time and temperature intervals are small and measurement errors in the temperature readings are large...
2017: MethodsX
https://www.readbyqxmd.com/read/28931677/structurally-guided-removal-of-deisgylase-biochemical-activity-from-papain-like-protease-originating-from-the-middle-east-respiratory-syndrome-virus
#17
Courtney M Daczkowski, Octavia Goodwin, John V Dzimianski, Jonathan J Farhat, Scott D Pegan
Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging human pathogen that is the causative agent for Middle East respiratory syndrome (MERS). With MERS outbreaks resulting in over 35% fatalities and now spread to 27 countries, MERS-CoV poses a significant on-going threat to global human health. As part of its viral genome, MERS-CoV encodes for a papain-like protease (PLpro) that has been observed to act as a deubiquitinase and deISGylase to antagonize IFN-I immune pathways. This activity is in addition to its viral polypeptide cleavage function...
September 20, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28930352/liquid-crystal-order-during-synthesis-affects-main-chain-liquid-crystal-elastomer-behavior
#18
N A Traugutt, R H Volpe, M S Bollinger, M O Saed, A H Torbati, K Yu, Natalia Dadivanyan, C M Yakacki
This study presents the first direct comparison of the influence of liquid-crystal order during synthesis on the thermo-mechanical behaviors of main-chain liquid-crystal elastomers (LCEs) in thiol-acrylate networks. Six polydomain nematic elastomer (PNE) chemistries were compared directly by synthesizing with the mesogens in either an isotropic state (i-PNE) or a nematic state (n-PNE). The i-PNE networks were created in the presence of solvent, which disrupted any liquid-crystal order during network formation...
September 20, 2017: Soft Matter
https://www.readbyqxmd.com/read/28930331/ils-through-the-looking-glass-electrostatics-and-structure-probed-using-charge-inverted-ionic-liquid-pairs
#19
Tiago F C Cruz, Karina Shimizu, José M S S Esperança, Luís Paulo N Rebelo, Pedro T Gomes, José N Canongia Lopes
Ionic liquids combining potassium cations with 1-alkyl-3-methylcyclopentadienyl anions, K[CnC1Cp] (n = 4, 6) have been synthesized. Differential scanning calorimetry measurements have shown that K[C4C1Cp] and K[C6C1Cp] melt without decomposition at around 90 °C. These two ionic liquids are the charge-inverted counterparts of [C4C1Im]Cl and [C6C1Im]Cl, two common ionic liquids. The concept of charge-inverted ionic pairs is used to explore the nature of the interactions and structure in different ionic compounds, from simple alkali halide salts to ionic liquids based on complex molecular ions...
September 20, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28929769/design-and-solidification-of-fast-releasing-clofazimine-nanoparticles-for-treatment-of-cryptosporidiosis
#20
Yingyue Zhang, Jie Feng, Simon A McManus, Hoang D Lu, Kurt D Ristroph, Eugene J Cho, Ellen L Dobrijevic, Hak-Kim Chan, Robert K Prud'homme
Clofazimine, a lipophilic (log P = 7.66) riminophenazine antibiotic approved by the US Food and Drug Administration (FDA) with a good safety record, was recently identified as a lead hit for cryptosporidiosis through a high-throughput phenotypic screen. Cryptosporidiosis requires fast-acting treatment as it leads to severe symptoms which, if untreated, result in morbidity for infants and small children. Consequently, a fast-releasing oral formulation of clofazimine in a water-dispersible form for pediatric administration is highly desirable...
September 20, 2017: Molecular Pharmaceutics
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