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https://www.readbyqxmd.com/read/28806680/sequestration-of-aluminium-iii-by-different-natural-and-synthetic-organic-and-inorganic-ligands-in-aqueous-solution
#1
Paola Cardiano, Rosalia Maria Cigala, Francesco Crea, Fausta Giacobello, Ottavia Giuffrè, Anna Irto, Gabriele Lando, Silvio Sammartano
The speciation of Al(3+) in aqueous solutions containing organic and inorganic ligands important from a biological (citrate (Cit(3-)), gluconate (Gluc(-)), lactate (Lac(-)), silicate (H2SiO4(2-)), carbonate (CO3(2-)), fluoride (F(-))) and industrial (Gantrez(®); polymethyl-vinyl-ether-co-maleic acids; GTZ S95 and GTZ AN169) point of view is reported. The stability constants of Al(3+)/L(z-) complexes (L(z-) = ligand with z(-) charge) were determined by potentiometry at T = 298.15 K and 0.10 ≤ I/M ≤ 1...
August 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/28792111/solid-state-nmr-h-n-c-h-and-h-n-c-c-3d-4d-correlation-experiments-for-resonance-assignment-of-large-proteins
#2
Hugo Fraga, Charles-Adrien Arnaud, Diego F Gauto, Maxime J C Audin, Vilius Kurauskas, Pavel Macek, Carsten Krichel, Jia-Ying Guan, Jérôme Boisbouvier, Remco Sprangers, Cécile Breyton, Paul Schanda
Solid-state NMR can provide insight into protein structure and dynamics at the atomic level without inherent protein size limitations. However, a major hurdle to studying large proteins by solid-state NMR spectroscopy is related to spectral complexity and resonance overlap, which increase with molecular weight and severely hamper the assignment process. Here we show the use of two sets of experiments that expand the tool kit of 1H-detected assignment approaches, and which correlate a given amide pair either to the two adjacent CO-CA pairs (4D hCOCANH/hCOCAcoNH), or to the amide 1H of the neighboring residue (3D HcocaNH/HcacoNH, which can be extended to up to 5D)...
August 9, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28791907/a-one-step-procedure-for-immobilising-the-thermostable-carbonic-anhydrase-sspca-on-the-surface-membrane-of-escherichia-coli
#3
Sonia Del Prete, Rosa Perfetto, Mosè Rossi, Fatmah A S Alasmary, Sameh M Osman, Zeid AlOthman, Claudiu T Supuran, Clemente Capasso
The carbonic anhydrase superfamily (CA, EC 4.2.1.1) of metalloenzymes is present in all three domains of life (Eubacteria, Archaea, and Eukarya), being an interesting example of convergent/divergent evolution, with its seven families (α-, β-, γ-, δ-, ζ-, η-, and θ-CAs) described so far. CAs catalyse the simple, but physiologically crucial reaction of carbon dioxide hydration to bicarbonate and protons. Recently, our groups characterised the α-CA from the thermophilic bacterium, Sulfurihydrogenibium yellowstonense finding a very high catalytic activity for the CO2 hydration reaction (kcat = 9...
December 2017: Journal of Enzyme Inhibition and Medicinal Chemistry
https://www.readbyqxmd.com/read/28790982/isolation-and-characterization-of-terrein-an-antimicrobial-and-antitumor-compound-from-endophytic-fungus-aspergillus-terreus-jas-2-associated-from-achyranthus-aspera-varanasi-india
#4
Jyoti Goutam, Gunjan Sharma, Vinod K Tiwari, Amrita Mishra, Ravindra N Kharwar, Vijayakumar Ramaraj, Biplob Koch
The present study aimed at characterizing biological potentials of endophyte Aspergillus terreus JAS-2 isolated from Achyranthus aspera. Crude extracted from endophytic fungus JAS-2 was purified and chemically characterized by chromatographic and spectroscopic studies respectively. Spectral assignment of NMR (nuclear magnetic resonance) data, (1)H proton and (13)C carbon analysis along with FTIR data elucidated the structure of compound as 4,5-Dihydroxy-3-(1-propenyl)-2-cyclopenten-1-one. After purification and identification a set of experiment was conducted to explore efficacy of compound...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28773219/ion-beam-modification-of-carbon-nanotube-yarn-in-air-and-vacuum
#5
Jonathan G Gigax, Philip D Bradford, Lin Shao
We studied the effects ion beam irradiation on carbon nanotube (CNT) yarns. CNT yarn was fabricated by drawing and spinning CNT sheets from a vertically aligned CNT forest. The yarn was irradiated by 2.5 MeV protons in either vacuum or air. Irradiation in air was achieved by directing the proton beam through a 0.025 mm thick Ti window. Irradiation in vacuum occurred at a pressure of <10(-6) torr at room temperature and at an elevated temperature of 600 °C. Tensile testing revealed that CNT yarn irradiated in air increased in tensile strength with increasing proton fluence...
July 27, 2017: Materials
https://www.readbyqxmd.com/read/28770302/acetobacter-pasteurianus-metabolic-change-induced-by-initial-acetic-acid-to-adapt-to-acetic-acid-fermentation-conditions
#6
Yu Zheng, Renkuan Zhang, Haisong Yin, Xiaolei Bai, Yangang Chang, Menglei Xia, Min Wang
Initial acetic acid can improve the ethanol oxidation rate of acetic acid bacteria for acetic acid fermentation. In this work, Acetobacter pasteurianus was cultured in ethanol-free medium, and energy production was found to increase by 150% through glucose consumption induced by initial acetic acid. However, oxidation of ethanol, instead of glucose, became the main energy production pathway when upon culturing ethanol containing medium. Proteome assay was used to analyze the metabolism change induced by initial acetic acid, which provided insight into carbon metabolic and energy regulation of A...
August 2, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28764925/profile-of-european-proton-and-carbon-ion-therapy-centers-assessed-by-the-eortc-facility-questionnaire
#7
Damien C Weber, André Abrunhosa-Branquinho, Alessandra Bolsi, Andrzej Kacperek, Rémi Dendale, Dirk Geismar, Barbara Bachtiary, Annika Hall, Jens Heufelder, Klaus Herfarth, Jürgen Debus, Maurizio Amichetti, Mechthild Krause, Roberto Orecchia, Vladimir Vondracek, Juliette Thariat, Tomasz Kajdrowicz, Kristina Nilsson, Cai Grau
BACKGROUND: We performed a survey using the modified EORTC Facility questionnaire (pFQ) to evaluate the human, technical and organizational resources of particle centers in Europe. MATERIAL AND METHODS: The modified pFQ consisted of 235 questions distributed in 11 sections accessible on line on an EORTC server. Fifteen centers from 8 countries completed the pFQ between May 2015 and December 2015. RESULTS: The average number of patients treated per year and per particle center was 221 (range, 40-557)...
July 29, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28764859/modeling-3d-csia-data-carbon-chlorine-and-hydrogen-isotope-fractionation-during-reductive-dechlorination-of-tce-to-ethene
#8
Boris M Van Breukelen, Heloïse A A Thouement, Philip E Stack, Mindy Vanderford, Paul Philp, Tomasz Kuder
Reactive transport modeling of multi-element, compound-specific isotope analysis (CSIA) data has great potential to quantify sequential microbial reductive dechlorination (SRD) and alternative pathways such as oxidation, in support of remediation of chlorinated solvents in groundwater. As a key step towards this goal, a model was developed that simulates simultaneous carbon, chlorine, and hydrogen isotope fractionation during SRD of trichloroethene, via cis-1,2-dichloroethene (and trans-DCE as minor pathway), and vinyl chloride to ethene, following Monod kinetics...
July 17, 2017: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28763166/comparison-of-three-methods-for-the-methylation-of-aliphatic-and-aromatic-compounds
#9
Hyejung Lee, Sarah J Feakins, Zhiyao Lu, Arndt Schimmelmann, Alex L Sessions, Jessica E Tierney, Travis J Williams
RATIONALE: Methylation protocols commonly call for acidic, hot conditions that are known to promote organic (1) H/(2) H exchange in aromatic and aliphatic C-H bonds. Here we tested two such commonly-used methods and compared a third that avoids these acidic conditions, to quantify isotope effects with each method and to directly determine acidic-exchange rates relevant to experimental conditions. METHODS: We compared acidic and non-acidic methylation approaches catalyzed by hydrochloric acid, acetyl chloride and EDCI (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) / DMAP (4-dimethylaminopyridine) respectively...
August 1, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28762335/helium-ions-at-the-heidelberg-ion-beam-therapy-center-comparisons-between-fluka-monte-carlo-code-predictions-and-dosimetric-measurements
#10
T Tessonnier, A Mairani, S Brons, P Sala, F Cerutti, A Ferrari, T Haberer, J Debus, K Parodi
In the field of particle therapy helium ion beams could offer an alternative for radiotherapy treatments, owing to their interesting physical and biological properties intermediate between protons and carbon ions. We present in this work the comparisons and validations of the Monte Carlo FLUKA code against in-depth dosimetric measurements acquired at the Heidelberg Ion Beam Therapy Center (HIT). Depth dose distributions in water with and without ripple filter, lateral profiles at different depths in water and a spread-out Bragg peak were investigated...
August 1, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28759793/modelling-recovery-of-ammonium-from-urine-by-electro-concentration-in-a-3-chamber-cell
#11
Emma Thompson Brewster, Johannes Jermakka, Stefano Freguia, Damien J Batstone
Electro-concentration enables treatment and nutrient recovery from source-separated urine, and is a potential technology for on-site treatment using a 3 compartment configuration that has anode, cathode and middle concentrate compartments. There is a particular focus on driving concentration towards the precipitation threshold in the concentrate compartment to generate solid ammonium salts, including ammonium bicarbonate. To evaluate controlling mechanisms and the feasibility of achieving high concentrations, a dynamic mechanistic model was developed and validated using experiments with synthetic urine...
July 20, 2017: Water Research
https://www.readbyqxmd.com/read/28755418/a-13-c-nmr-method-for-determining-secondary-nitroxide-substrate-associations
#12
Nicholas A Eddy, Michael S Martin, Pranjali Ichalkaranje, Martha D Morton
The major effects of nitroxides on substrates in proton spectra is well studied, while the effect on carbon spectra has received less attention. Present knowledge relies on chemical shift differences between diamagnetic and paramagnetic solutions of the substrates to propose interactions. Changes in scalar coupling constants (JCH ) would, however, provide better insight. Herein, we present a method of utilizing coupled (13) C NMR spectra where differences in (1) JCH coupling show alternate modes of association between nitroxides and test substrates...
July 28, 2017: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/28748627/genetic-ablation-of-carbonic-anhydrase-ix-disrupts-gastric-barrier-function-via-claudin-18-downregulation-and-acid-backflux
#13
Taolang Li, Xuemei Liu, Brigitte Riederer, Katerina Nikolovska, Anurag Kumar Singh, Kari A Mäkelä, Anna Seidler, Yongjian Liu, Gerolf Gros, Helmut Bartels, Karl Heinz Herzig, Ursula Seidler
AIM: The study aims to explore the molecular mechanisms for the parietal cell loss and fundic hyperplasia observed in gastric mucosa of mice lacking the carbonic anhydrase 9 (CAIX). METHODS: We assessed the ability of CAIX knockout and WT gastric surface epithelial cells to withstand luminal acid load by measuring the pHi of exteriorized gastric mucosa in vivousing two photon confocal laser scanning microscopy. Cytokines and claudin-18A2 expression was analyzed by RT-PCR...
July 27, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28745360/investigating-synergistic-interactions-of-group-4-5-and-6-metals-with-gold-nanoparticles-for-the-catalysis-of-the-electrochemical-hydrogen-evolution-reaction
#14
Ubisha Joshi, Souradip Malkhandi, Boon Siang Yeo
An investigation of the catalysis of the electrochemical hydrogen evolution reaction (HER, 2H(+) + 2e(-) → H2) in aqueous 0.5 M H2SO4 electrolyte using composites consisting of gold nanoparticles (AuNP), carbon (Black Pearl 2000) and group 4, 5, and 6 metals is presented. This study is a continuation of our earlier work (Phys. Chem. Chem. Phys., 2016, 18, 21548-21553) on molybdenum and AuNP, which we found to interact synergistically to enhance the HER. We demonstrate here that tungsten not only also showed synergy with AuNP, but the extent of synergy is even larger than that of the Mo-AuNP composite...
August 9, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28742967/molybdenum-0-dihapto-coordination-of-benzene-and-trifluorotoluene-the-stabilizing-and-chemo-directing-influence-of-a-cf3-group
#15
Jeffery T Myers, Jacob A Smith, Steven J Dakermanji, Justin H Wilde, Katy B Wilson, Philip J Shivokevich, W Dean Harman
The preparation of the complex TpMo(NO)(DMAP)(η2-PhCF3) (5) and TpMo(NO)(DMAP)(η2-benzene) (3) are described. The CF3 group is found to stabilize the metal-arene bond strength in 5 by roughly 3 kcal/mol, compared to 3, allowing the large-scale synthesis and isolation of the trifluorotoluene analog (5, 37 g, 70%). When a benzene solution of 5 is allowed to stand, clean conversion to the benzene analog 3 occurs, and this complex may be precipitated from solution upon the addition of pentane, and isolated...
July 25, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28742965/sequential-tandem-addition-to-a-tungsten-trifluorotoluene-complex-a-versatile-method-for-the-preparation-of-highly-functionalized-trifluoromethylated-cyclohexenes
#16
Katy B Wilson, Jeffery T Myers, Hannah S Nedzbala, Logan A Combee, Michal Sabat, W Dean Harman
The effects of an electron-withdrawing group on the organic chemistry of an η(2)-bound benzene ring are explored using the complex TpW(NO)(PMe3)(η(2)-PhCF3). This trifluorotoluene complex was found to undergo a highly regio- and stereoselective 1,2-addition reaction involving protonation of an ortho carbon followed by addition of a carbon nucleophile. The resulting 1,3-diene complexes can undergo a second protonation and nucleophilic addition with a range of nucleophiles including hydrides, amines, cyanide, and protected enolates...
August 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28741854/toward-activity-origin-of-electrocatalytic-hydrogen-evolution-reaction-on-carbon-rich-crystalline-coordination-polymers
#17
Lihuan Wang, Diana C Tranca, Jian Zhang, Yanpeng Qi, Stavroula Sfaelou, Tao Zhang, Renhao Dong, Xiaodong Zhuang, Zhikun Zheng, Gotthard Seifert
The fundamental understanding of electrocatalytic active sites for hydrogen evolution reaction (HER) is significantly important for the development of metal complex involved carbon electrocatalysts with low kinetic barrier. Here, the MSx Ny (M = Fe, Co, and Ni, x/y are 2/2, 0/4, and 4/0, respectively) active centers are immobilized into ladder-type, highly crystalline coordination polymers as model carbon-rich electrocatalysts for H2 generation in acid solution. The electrocatalytic HER tests reveal that the coordination of metal, sulfur, and nitrogen synergistically facilitates the hydrogen ad-/desorption on MSx Ny catalysts, leading to enhanced HER kinetics...
July 25, 2017: Small
https://www.readbyqxmd.com/read/28737893/uncondensed-graphitic-carbon-nitride-on-reduced-graphene-oxide-for-oxygen-sensing-via-a-photoredox-mechanism
#18
James E Ellis, Dan C Sorescu, Seth C Burkert, David L White, Alexander Star
Melon, a polymeric, uncondensed graphitic carbon nitride with a two-dimensional structure, has been coupled with reduced graphene oxide (rGO) to create an oxygen chemiresistor sensor that is active under UV photoactivation. Oxygen gas is an important sensor target in a variety of areas including industrial safety, combustion process monitoring, as well as environmental and biomedical fields. Because of the intimate electrical interface formed between melon and rGO, charge transfer of photoexcited electrons occurs between the two materials when under UV (λ = 365 nm) irradiation...
August 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28731268/-13-c-metabolic-flux-profiling-of-pichia-pastoris-grown-in-aerobic-batch-cultures-on-glucose-revealed-high-relative-anabolic-use-of-tca-cycle-and-limited-incorporation-of-provided-precursors-of-branched-chain-amino-acids
#19
Meng Zhang, Xiao-Wei Yu, Yan Xu, Paula Jouhten, Gurla V T Swapna, Ralf W Glaser, John F Hunt, Gaetano T Montelione, Hannu Maaheimo, Thomas Szyperski
Carbon metabolism of Crabtree-negative yeast Pichia pastoris was profiled using (13) C nuclear magnetic resonance (NMR) to delineate regulation during exponential growth and to study the import of two precursors for branched-chain amino acid biosynthesis, α-ketoisovalerate and α-ketobutyrate. Cells were grown in aerobic batch cultures containing (a) only glucose, (b) glucose along with the precursors, or (c) glucose and Val. The study provided the following new insights. First, (13) C flux ratio analyses of central metabolism reveal an unexpectedly high anaplerotic supply of the tricarboxylic acid cycle for a Crabtree-negative yeast, and show that a substantial fraction of glucose catabolism proceeds through the pentose phosphate pathway...
July 21, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28731076/simple-gd-3-neu5nac-complexation-results-in-nmr-chemical-shift-asymmetries-of-structurally-equivalent-complex-type-n-glycan-branches
#20
Konstantin Usachev, Yoshiki Yamaguchi, Masayuki Takamatsu, Nataliya Pavlova, Vladimir Klochkov, Almira Kurbangalieva, Takefumi Murase, Taiji Shimoda, Katsunori Tanaka
In the present Communication, we propose a quite simple but previously overlooked approach for conveniently analyzing, assigning, and extracting sialic acid-containing N-glycan structures using high-resolution NMR spectroscopy without pre-installing metal chelators. Paramagnetic metals, such as Gd(3+), appear to bind to the carboxyl groups of N-acetylneuraminic acid when introduced at room temperature, leading to the measurement of nonequivalent proton and carbon NMR spectral signals among otherwise "identical" glycan branched structures...
August 7, 2017: Analyst
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