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https://www.readbyqxmd.com/read/28445823/engineering-metal-hydr-oxide-sorbents-for-removal-of-arsenate-and-similar-weak-acid-oxyanion-contaminants-a-critical-review-with-emphasis-on-factors-governing-sorption-processes
#1
Kiril D Hristovski, Jasmina Markovski
To create an integrative foundation for engineering of the next generation inexpensive sorbent systems, this critical review addresses the existing knowledge gap in factor/performance relationships between weak-acid oxyanion contaminants and metal (hydr)oxide sorbents. In-depth understanding of fundamental thermodynamics and kinetics mechanisms, material fabrication, and analytical and characterization techniques, is necessary to engineer sorbent that exhibit high capacity, selectivity, stability, durability and mass transport of contaminants under a wide range of operating and water matrix conditions requirements...
April 22, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28445763/myosin-rod-hypophosphorylation-and-cb-kinetics-in-papillary-muscles-from-a-tnc-a8v-ki-mouse-model
#2
Masataka Kawai, Jamie R Johnston, Tarek Karam, Li Wang, Rakesh K Singh, Jose R Pinto
The cardiac troponin C (TnC)-A8V mutation is associated with hypertrophic and restrictive cardiomyopathy (HCM and RCM) in human and mice. The residue affected lies in the N-helix, a region known to affect Ca(2+)-binding affinity to the N-terminal domain. Here we report on the functional effects of this mutation in skinned papillary muscle fibers from homozygous knock-in TnC-A8V mice. Muscle fibers from left ventricle were activated at 25°C under the ionic conditions of working cardiomyocytes. The pCa-tension relationship showed a 3× increase in Ca(2+)-sensitivity and a decrease (0...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445754/probing-the-dynamics-of-clot-bound-thrombin-at-venous-shear-rates
#3
Laura M Haynes, Thomas Orfeo, Kenneth G Mann, Stephen J Everse, Kathleen E Brummel-Ziedins
In closed system models of fibrin formation, exosite-mediated thrombin binding to fibrin contributes to clot stability and is resistant to inhibition by antithrombin/heparin while still susceptible to small, active-site inhibitors. Each molecule of fibrin can bind ∼1.6 thrombin molecules at low-affinity binding sites (Kd = 2.8 μM) and ∼0.3 molecules of thrombin at high-affinity binding sites (Kd = 0.15 μM). The goal of this study is to assess the stability of fibrin-bound thrombin under venous flow conditions and to determine both its accessibility and susceptibility to inhibition...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445753/pyroglutamate-modified-amyloid-%C3%AE-3-42-shows-%C3%AE-helical-intermediates-before-amyloid-formation
#4
Christina Dammers, Kerstin Reiss, Lothar Gremer, Justin Lecher, Tamar Ziehm, Matthias Stoldt, Melanie Schwarten, Dieter Willbold
Pyroglutamate-modified amyloid-β (pEAβ) has been described as a relevant Aβ species in Alzheimer's-disease-affected brains, with pEAβ (3-42) as a dominant isoform. Aβ (1-40) and Aβ (1-42) have been well characterized under various solution conditions, including aqueous solutions containing trifluoroethanol (TFE). To characterize structural properties of pEAβ (3-42) possibly underlying its drastically increased aggregation propensity compared to Aβ (1-42), we started our studies in various TFE-water mixtures and found striking differences between the two Aβ species...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445749/equilibrium-ensembles-for-insulin-folding-from-bias-exchange-metadynamics
#5
Richa Singh, Rohit Bansal, Anurag Singh Rathore, Gaurav Goel
Earliest events in the aggregation process, such as single molecule reconfiguration, are extremely important and the most difficult to characterize in experiments. To this end, we have used well-tempered bias exchange metadynamics simulations to determine the equilibrium ensembles of an insulin molecule under amyloidogenic conditions of low pH and high temperature. A bin-based clustering method that uses statistics accumulated in bias exchange metadynamics trajectories was employed to construct a detailed thermodynamic and kinetic model of insulin folding...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445704/development-of-standard-methods-for-zika-virus-propagation-titration-and-purification
#6
Sharton Vinicius Antunes Coelho, Rômulo Leão Silva Neris, Michelle Premazzi Papa, Laila Castro Schnellrath, Lana Monteiro Meuren, Diogo A Tschoeke, Luciana Leomil, Brunno Renato Farias Verçoza, Milene Miranda, Fabiano L Thompson, Andrea Thompson Da Poian, Thiago Moreno L Souza, Fabiana Avila Carneiro, Clarissa R Damaso, Iranaia Assunção-Miranda, Luciana Barros de Arruda
The emergence of Zika virus (ZIKV) infection has stimulated several research groups to study and collaborate to understand virus biology and pathogenesis. These efforts may assist with the development of antiviral drugs, vaccines and diagnostic tests, as well as to promote advancements in public health policies. Here, we aim to develop standard protocols for propagation, titration, and purification of Asian and Brazilian ZIKV strains, by systematically testing different cell types, kinetics, multiplicity of infection and centrifugation protocols...
April 23, 2017: Journal of Virological Methods
https://www.readbyqxmd.com/read/28445648/electron-radiolysis-of-ammonium-perchlorate-a-reflectron-time-of-flight-mass-spectrometric-study
#7
Sándor Góbi, Alexandre Bergantini, Andrew M Turner, Ralf I Kaiser
Thin films of ammonium perchlorate (NH4ClO4) were exposed to energetic electrons at 5.5 K to explore the radiolytic decomposition mechanisms. The effects of radiolysis were monitored on line and in situ via Fourier-transform infrared spectroscopy (FTIR) in the condensed phase along with electron impact ionization quadrupole mass spectrometry (EI-QMS) and single-photon photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS) during the temperature programmed desorption (TPD) phase to probe the subliming molecules...
April 26, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28445626/fabrication-and-characterization-of-chitosan-polyvinylpyrrolidone-and-cellulose-nanowhiskers-nanocomposite-films-for-wound-healing-drug-delivery-application
#8
Abshar Hasan, Gyan Waibhaw, Sakshi Tiwari, K Dharmalingam, I Shukla, Lalit M Pandey
This study describes the preparation of composite film using chitosan (CS) and polyvinylpyrrolidone (PVP) with incorporated cellulose nanowhiskers (CNWs) for drug delivery application. CNWs were prepared by acid hydrolysis of cellulose with sulfuric acid. Field emission scanning electron microscopy studies revealed nanofibrous morphology of CNWs with 20-30 nm diameter and 200-250 nm in length. X-ray powder diffraction (XRD) analysis confirmed highly crystalline nature of CNWs with 92.81% crystallinity. Incorporation of CNWs enhanced the thermal and mechanical properties of films...
April 26, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28445622/thiocarbohydrates-on-gold-nanoparticles-strong-influences-of-stereocenters-on-binding-affinitiy-and-interparticle-forces
#9
Torsten Linker, Prashant Pavashe, Werner Fudickar
Carbohydrates carrying thiol groups at the C-2 position have been attached to gold nanoparticles (AuNP) with stereocenters in close proximity to the surface for the first time. Their configurations can be clearly distinguished by the tendency of particle aggregation. AuNP surface plasmon resonance (SPR), x-ray photoelectron spectroscopy (XPS), and IR spectroscopy indicate that the thiocarbohydrates replace citrate molecules at different rates causing aggregation and eventually precipitation. A quantitative formulation of this aggregation process shows that reactivities can vary by several magnitudes...
April 26, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28445455/structural-insight-into-allosteric-modulation-of-protease-activated-receptor-2
#10
Robert K Y Cheng, Cédric Fiez-Vandal, Oliver Schlenker, Karl Edman, Birte Aggeler, Dean G Brown, Giles A Brown, Robert M Cooke, Christoph E Dumelin, Andrew S Doré, Stefan Geschwindner, Christoph Grebner, Nils-Olov Hermansson, Ali Jazayeri, Patrik Johansson, Louis Leong, Rudi Prihandoko, Mathieu Rappas, Holly Soutter, Arjan Snijder, Linda Sundström, Benjamin Tehan, Peter Thornton, Dawn Troast, Giselle Wiggin, Andrei Zhukov, Fiona H Marshall, Niek Dekker
Protease-activated receptors (PARs) are a family of G-protein-coupled receptors (GPCRs) that are irreversibly activated by proteolytic cleavage of the N terminus, which unmasks a tethered peptide ligand that binds and activates the transmembrane receptor domain, eliciting a cellular cascade in response to inflammatory signals and other stimuli. PARs are implicated in a wide range of diseases, such as cancer and inflammation. PARs have been the subject of major pharmaceutical research efforts but the discovery of small-molecule antagonists that effectively bind them has proved challenging...
April 26, 2017: Nature
https://www.readbyqxmd.com/read/28445143/the-igh-locus-relocalizes-to-a-recombination-compartment-in-the-perinucleolar-region-of-differentiating-b-lymphocytes
#11
Andrey Pichugin, Olga V Iarovaia, Alexey Gavrilov, Ilya Sklyar, Natalja Barinova, Aleksandr Barinov, Evgeny Ivashkin, Gersende Caron, Said Aoufouchi, Sergey V Razin, Thierry Fest, Marc Lipinski, Yegor S Vassetzky
The immunoglobulin heavy chain (IGH) gene loci are subject to specific recombination events during B-cell differentiation including somatic hypermutation and class switch recombination which mark the end of immunoglobulin gene maturation in germinal centers of secondary lymph nodes. These two events rely on the activity of activation-induced cytidine deaminase (AID) which requires DNA double strand breaks be created, a potential danger to the cell. Applying 3D-fluorescence in situ hybridization coupled with immunofluorescence staining to a previously described experimental system recapitulating normal B-cell differentiation ex vivo, we have kinetically analyzed the radial positioning of the two IGH gene loci as well as their proximity with the nucleolus, heterochromatin and γH2AX foci...
April 7, 2017: Oncotarget
https://www.readbyqxmd.com/read/28445137/monitoring-of-kras-mutated-ctdna-to-discriminate-pseudo-progression-from-true-progression-during-anti-pd-1-treatment-of-lung-adenocarcinoma
#12
Nicolas Guibert, Julien Mazieres, Myriam Delaunay, Anne Casanova, Magali Farella, Laura Keller, Gilles Favre, Anne Pradines
OBJECTIVES: Pseudo-progression is a rare but worrying situation for both clinicians and patients during immunotherapy. Dedicated ir-RECIST criteria have been established to improve this situation. However, this can be sometimes considered inadequate and patients experiencing true progression may then receive inefficient treatments. Additional reliable tools to discriminate pseudo from true progression are thus needed. So far, no biomarker has been identified to distinguish pseudo from true progression...
April 7, 2017: Oncotarget
https://www.readbyqxmd.com/read/28445031/importance-of-loop-l1-dynamics-for-substrate-capture-and-catalysis-in-pseudomonas-aeruginosa-d-arginine-dehydrogenase
#13
Daniel Ouedraogo, Michael Souffrant, Sheena Vasquez, Donald Hamelberg, Giovanni Gadda
Mobile loops located at the active site entrance in enzymes often participate in conformational changes required to shield the reaction from bulk solvent, to control substrate access to the active site, and to position residues for substrate binding and catalysis. In D-arginine dehydrogenase from Pseudomonas aeruginosa (PaDADH) previous crystallographic data suggested that residues 45-47 in the FAD-binding domain and 50-56 in the substrate-binding domain in loop L1 could adopt two distinct conformations. In this study, we have used molecular dynamics, kinetics, and fluorescence spectroscopy on the S45A and A46G enzyme variants of PaDADH to investigate the impact of mutations of loop L1 on the catalytic function of the enzyme...
April 26, 2017: Biochemistry
https://www.readbyqxmd.com/read/28445026/chromium-poisoning-effects-on-surface-exchange-kinetics-of-la0-6sr0-4co0-2fe0-8o3-%C3%AE
#14
Yi-Lin Huang, A Mohammed Hussain, Christopher Pellegrinelli, Chunyan Xiong, Eric D Wachsman
The presence of Cr has already been reported in literature to cause severe degradation to La0.6Sr0.4Co0.2Fe0.8O3- δ (LSCF). However, fundamental understanding of Cr effects on the surface exchange kinetics is still lacking. For the first time in-situ gas phase isotopic oxygen exchange was utilized to quantitatively determine Cr effect on oxygen exchange kinetics of LSCF powder as a function of temperature and water vapor. Our investigations revealed that the formation of secondary phases, such as SrCrO¬4, Cr2O3, Cr-Co-Fe-O, and La-Co-Fe-O, can affect both the oxygen dissociation step and overall surface exchange...
April 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28444930/does-postexercise-modelled-capillary-blood-flow-accurately-reflect-cardiovascular-effects-by-different-exercise-intensities
#15
F Stöcker, C Von Oldershausen, F K Paternoster, T Schulz, R Oberhoffer
Blood flow (BF) in exercising muscles is an important factor for exercise capacity. Recently, a non-invasive method to estimate capillary BF (Qcap ) was introduced. Using this method, the Fick principle is re-arranged by using relative differences in deoxygenated haemoglobin (ΔHHb) as a surrogate for arteriovenous O2 difference and pulmonary oxygen uptake (VO2 ) instead of muscular oxygen uptake. The aim of this study was to examine (I) the relationship between Qcap and exercise intensity during and following exercise, and (II) to critically reflect the Qcap approach...
April 26, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28444918/kinetic-resolution-of-2-substituted-indolines-by-n-sulfonylation-using-an-atropisomeric-4-dmap-n-oxide-organocatalyst
#16
James I Murray, Nils J Flodén, Adriano Bauer, Nico D Fessner, Daniel L Dunklemann, Opetoritse Bob-Egbe, Henry S Rzepa, Thomas Bürgi, Jeffery Richardson, Alan C Spivey
The first catalytic kinetic resolution by N-sulfonylation is described. 2-Substituted indolines are resolved (s=2.6-19) using an atropisomeric 4-dimethylaminopyridine-N-oxide (4-DMAP-N-oxide) organocatalyst. Use of 2-isopropyl-4-nitrophenylsulfonyl chloride is critical to the stereodiscrimination and enables facile deprotection of the sulfonamide products with thioglycolic acid. A qualitative model that accounts for the stereodiscrimination is proposed.
April 26, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28444869/assessment-of-the-usage-of-biodegradable-polymeric-matrix-in-vaginal-devices-to-sustain-progesterone-release-in-cows
#17
José Rodrigo Valim Pimentel, Milton Maturana Filho, Lucio Cardozo-Filho, José Augusto M Agnelli, Jefter Nascimento, Ed Hoffmann Madureira
The usage of timed artificial insemination (TAI) at a low cost leading to better reproductive rates has been the aim of several research groups in the field. Usually during TAI protocols, sustained progesterone (P4 ) release devices are employed. Most devices are constituted of a nylon skeleton covered with a silicon layer with P4 . A device based on biopolymers was developed in order to reduce costs and decrease its environmental impact. In this study, we compared the kinetics of sustained progesterone release among devices manufactured with a polymeric blend made of polyhydroxybutyrate-valerate (PHBV) and poly-ε-caprolactone (PCL) (DISP) which were compared with DIB® (Internal Bovine Device) used as the control...
April 25, 2017: Animal Science Journal, Nihon Chikusan Gakkaihō
https://www.readbyqxmd.com/read/28444793/dietary-mannoheptulose-does-not-alter-glucose-or-lipid-metabolism-in-adult-labrador-retrievers
#18
L L McKnight, J France, D Wright, G Davenport, A K Shoveller
Mannoheptulose (MH), a glycolytic inhibitor, has been preliminarily investigated as a novel functional food ingredient for dogs. This study aimed to determine the effects of dietary MH, delivered as an extract of un-ripened avocados, on fatty acid and glucose kinetics in healthy adult Labrador Retriever dogs (n = 12 dogs). The study was a double-blindcrossover with each dog receiving both dietary treatments, control (CON) and MH (400 mg/kg of diet), in random order. Glucose and glycerol plasma turnover (Ra) and oxidation (Ox) were measured in fasting and in response to repeated meal feeding ("fed") with stable isotope tracers (U-(13) C-glucose, 1,1,2,3,3-D5 -glycerol) and indirect calorimetry...
April 26, 2017: Journal of Animal Physiology and Animal Nutrition
https://www.readbyqxmd.com/read/28444761/photon-counting-ct-for-simultaneous-imaging-of-multiple-contrast-agents-in-the-abdomen-an-in-vivo-study
#19
Rolf Symons, Bernhard Krauss, Pooyan Sahbaee, Tyler E Cork, Manu N Lakshmanan, David A Bluemke, Amir Pourmorteza
PURPOSE: To demonstrate the feasibility of spectral imaging using photon-counting detector (PCD) x-ray computed tomography (CT) for simultaneous material decomposition of 3 contrast agents in vivo in a large animal model. METHODS: This Institutional Animal Care and Use Committee-approved study used a canine model. Bismuth subsalicylate was administered orally 24-72 hours before imaging. PCD CT was performed during intravenous administration of 40-60 ml gadoterate meglumine; 3...
April 26, 2017: Medical Physics
https://www.readbyqxmd.com/read/28444733/hybridization-increases-mitochondrial-production-of-reactive-oxygen-species-in-sunfish
#20
Sherry N N Du, Fariborz Khajali, Neal J Dawson, Graham R Scott
Mitochondrial dysfunction and oxidative stress have been suggested to be possible mechanisms underlying hybrid breakdown, as a result of mito-nuclear incompatibilities in respiratory complexes of the electron transport system. However, it remains unclear whether hybridization increases the production of reactive oxygen species (ROS) by mitochondria. We used high-resolution respirometry and fluorometry on isolated liver mitochondria to examine mitochondrial physiology and ROS emission in naturally occurring hybrids of pumpkinseed (Lepomis gibbosus) and bluegill (L...
April 26, 2017: Evolution; International Journal of Organic Evolution
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