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https://www.readbyqxmd.com/read/29145122/the-myo-inositol-proton-symporter-iolt1-contributes-to-d-xylose-uptake-in-corynebacterium-glutamicum
#1
Christian Brüsseler, Andreas Radek, Niklas Tenhaef, Karin Krumbach, Stephan Noack, Jan Marienhagen
Corynebacterium glutamicum has been engineered to utilize d-xylose as sole carbon and energy source. Recently, a C. glutamicum strain has been optimized for growth on defined medium containing d-xylose by laboratory evolution, but the mutation(s) attributing to the improved-growth phenotype could not be reliably identified. This study shows that loss of the transcriptional repressor IolR is responsible for the increased growth performance on defined d-xylose medium in one of the isolated mutants. Underlying reason is derepression of the gene for the glucose/myo-inositol permease IolT1 in the absence of IolR, which could be shown to also contribute to d-xylose uptake in C...
November 1, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29143152/electrochemical-and-theoretical-studies-of-the-interactions-of-a-pyridyl-based-corrosion-inhibitor-with-iron-clusters-fe15-fe30-fe45-and-fe60
#2
Julian Cruz-Borbolla, Esteban Garcia-Ochoa, Jayanthi Narayanan, Pablo Maldonado-Rivas, Thangarasu Pandiyan, José M Vásquez-Pérez
The capacity of 2,6-bis[((2-pyridylmethyl)oxy)methyl)]pyridine (BPMMP) to inhibit the corrosion of mild carbon steel in HCl was analyzed. In a polarization study, both the cathodic and anodic currents were appreciably decreased in the presence of BPMMP, suggesting that this ligand is effective at inhibiting corrosion at the metal surface. This conclusion is consistent with the results of impedance analysis, where only one time constant corresponding to one depressed capacitive loop was detected, and the diameter of the impedance plot was directly related to the concentration of BPMMP...
November 15, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/29140603/protic-nnn-and-ncn-pincer-type-ruthenium-complexes-featuring-trifluoromethyl-pyrazole-arms-synthesis-and-application-to-catalytic-hydrogen-evolution-from-formic-acid
#3
Yoshiko Nakahara, Tatsuro Toda, Asuka Matsunami, Yoshihito Kayaki, Shigeki Kuwata
The NNN and NCN pincer-type ruthenium(II) complexes featuring two protic pyrazol-3-yl arms with a trifluoromethyl (CF3) group at the 5-position were synthesized and structurally characterized to evaluate the impact of the substitution on the properties and catalysis. The Brønsted acidity increased by the highly electron-withdrawing CF3 pendants was demonstrated by the protonation-deprotonation experiments. By contrast, the infrared spectra of the carbonyl derivatives as well as the cyclic voltammogram indicated that the electron density of the ruthenium atom is little influenced by the CF3 group...
November 15, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29136787/-1-h-nmr-assisted-quantification-of-glycerol-carbonate-in-the-mixture-of-glycerol-and-glycerol-carbonate
#4
Avneet Kaur, Ranjana Prakash, Amjad Ali
Glycerol carbonate (GLC) is a very important chemical having a variety of application viz., green solvent in organic synthesis, an electrolyte in lithium batteries, wetting agent in cosmetics and precursor in polymer and food industry for the synthesis of 1,3-sn-diglycerides. Hence, it is vital to find out the quick and simple method for the quantification of GLC when it is synthesized via dimethyl carbonate (DMC) assisted transesterification with glycerol (GL). Present study, proposes simple, accurate and non destructive quantitative proton nuclear magnetic resonance (qHNMR) method for the determination of GLC...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136081/imaging-the-dynamics-of-ion-molecule-reactions
#5
REVIEW
Eduardo Carrascosa, Jennifer Meyer, Roland Wester
A range of ion-molecule reactions have been studied in the last years using the crossed-beam ion imaging technique, from charge transfer and proton transfer to nucleophilic substitution and elimination. This review presents the detailed insights that have been gained with respect to the dynamics of both cation-molecule and anion-molecule reactions studied with this method. In particular, we show the recent progress that has been achieved to understand the atomistic energetics and dynamics of ion-molecule reactions, such as the effects of vibrational quantum states, the formation of carbon-carbon bonds, and the competition between nucleophilic substitution and elimination...
November 14, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/29134806/acid-catalyzed-skeletal-rearrangements-in-arenes-aryl-vs-alkyl-ring-pirouettes-in-anthracene-and-phenanthrene
#6
Sarah L Skraba-Joiner, Jeffrey W Brulet, Min K Song, Richard P Johnson
In 1 M triflic acid/dichloroethane, anthracene is completely protonated at C9 and the resulting 9-anthracenium ion is easily observed at ambient temperature. When heated at > 84 °C as a dilute (10-3 M) solution in 1 M triflic acid/dichloroethane (DCE), anthracene undergoes conversion to phenanthrene as the major volatile product. Minor dihydro and tetrahydro products are also observed. MALDI analysis supports the simultaneous formation of oligomers, primarily dimeric, which represent 10 - 60% of the product mixture...
November 14, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29134686/selective-proton-observed-carbon-edited-selpoce-mrs-method-for-measurement-of-glutamate-and-glutamine-13-c-labeling-in-the-human-frontal-cortex
#7
Henk M De Feyter, Raimund I Herzog, Bart R Steensma, Dennis W J Klomp, Peter B Brown, Graeme F Mason, Douglas L Rothman, Robin A de Graaf
PURPOSE: (13) C magnetic resonance spectroscopy (MRS) in combination with infusion of (13) C-labeled substrates has led to unique insights into human brain metabolism and neurotransmitter cycling. However, the low sensitivity of direct (13) C MRS and high radiofrequency power requirements has limited (13) C MRS studies to predominantly data acquisition in large volumes of the occipital cortex. The purpose of this study is to develop an MRS technique for localized detection of (13) C-labeling of glutamate and glutamine in the human frontal lobe...
November 13, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29131471/the-toxicological-effects-of-some-avermectins-on-goat-liver-carbonic-anhydrase-enzyme
#8
Cuneyt Caglayan, İlhami Gulcin
Avermectins are used worldwide as antiparasitic drugs in the field of veterinary medicine and as agricultural pesticides and insecticides. Carbonic anhydrase (CA, E.C. 4.2.1.1) is a zinc-containing metalloenzyme that catalyzes the reversible hydration of carbon dioxide (CO2 ) to yield protons (H(+) ) and bicarbonate (HCO3(-) ). In this study, some avermectins, including abamectin, doramectin, eprinomectin, and moxidectin, were investigated for in vitro inhibitory effects on the CA enzyme purified from goat liver, which was purified (125...
November 13, 2017: Journal of Biochemical and Molecular Toxicology
https://www.readbyqxmd.com/read/29127743/three-dimensional-graphene-networks-with-abundant-sharp-edge-sites-for-efficient-electrocatalytic-hydrogen-evolution
#9
Gui Yu, Huping Wang, Xu-Bing Li, Lei Gao, Hao-Lin Wu, Jie Yang, Le Cai, Tian-Bao Ma, Chen-Ho Tung, Li-Zhu Wu
To achieve sustainable production of hydrogen (H2) through water splitting, establishing efficient and earth-abundant electrocatalysts is of great necessity. Here, we firstly reveal that morphology engineering of graphene can modulate the electronic structure of carbon skeleton and in turn endow it with excellent ability of proton reduction. Three-dimensional (3D) graphene networks with the high density of sharp edge sites are synthesized. Electrocatalytic measurements indicate that the obtained 3D graphene networks can electrocatalyze H2 evolution with an extremely low onset potential of ~18 mV in 0...
November 11, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29121512/composite-pulse-and-partially-dipolar-dephased-multicp-for-improved-quantitative-solid-state-13-c-nmr
#10
Pu Duan, Klaus Schmidt-Rohr
Improved multiple cross polarization (multiCP) pulse sequences for quickly acquiring quantitative (13)C NMR spectra of organic solids are presented. Loss of (13)C magnetization due to imperfect read-out and storage pulses in multiCP has been identified as a significant mechanism limiting polarization enhancement for (13)C sites with weak couplings to (1)H. This problem can be greatly reduced by composite 90° pulses with non-orthogonal phases that flip the magnetization onto the spin-lock field and back to the longitudinal direction for the (1)H repolarization period; the observed loss is <3% for over ±10 kHz resonance offset and up to 20% flip-angle error...
November 6, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29121067/high-yields-of-hydrogen-production-from-methanol-steam-reforming-with-a-cross-u-type-reactor
#11
Shubin Zhang, Yufeng Zhang, Junyu Chen, Xuelin Zhang, Xiaowei Liu
This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation...
2017: PloS One
https://www.readbyqxmd.com/read/29119856/radiological-properties-of-healthy-carcinoma-and-equivalent-breast-tissues-for-photon-and-charged-particle-interactions
#12
M Büyükyıldız, M Kurudirek
PURPOSE: In this paper, the effective atomic numbers (Zeff), electron densities (Neff), exposure buildup factor (EBF) and energy absorption buildup factor (EABF) of healthy (H), carcinoma (C) and equivalent (E) breast tissues were investigated to quantify differences in radiological parameters between the tissues in the continuous energy region. For these purposes, Zeffs and Neffs, of healthy, carcinoma and equivalent (H-C-E) breast tissues were calculated for interaction of gamma rays and charged particles with selected tissues...
November 9, 2017: International Journal of Radiation Biology
https://www.readbyqxmd.com/read/29119623/exponential-activation-of-carbonic-anhydrase-by-encapsulation-in-dynameric-host-matrices-with-chiral-discrimination
#13
Mihail Barboiu, Yan Zhang, Claudiu Supuran
This paper reports an unexpected exponential activation of bovine carbonic anhydrase (bCA) in aqueous solutions in the presence of dynameric host matrices. Successive experiments confirmed the important role of the dynamic imine-exchanges within the dynameric host structures for the direct enzyme activation. It allows the optimal encapsulation of guest enzyme, while the presence of external proton-sponge amino groups is less important. We note that the no-exchanging polymeric sec-amine congeners resulted from imine reduction of dynameric structures, show no obvious activation on bCA...
November 9, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29116014/quantitative-assessment-of-radiation-dose-and-fractionation-effects-on-normal-tissue-by-utilizing-a-novel-lung-fibrosis-index-model
#14
Cheng Zhou, Bleddyn Jones, Mahmoud Moustafa, Christian Schwager, Julia Bauer, Bing Yang, Liji Cao, Min Jia, Andrea Mairani, Ming Chen, Longhua Chen, Juergen Debus, Amir Abdollahi
BACKGROUND: Normal lung tissue tolerance constitutes a limiting factor in delivering the required dose of radiotherapy to cure thoracic and chest wall malignancies. Radiation-induced lung fibrosis (RILF) is considered a critical determinant for late normal tissue complications. While RILF mouse models are frequently approached e.g., as a single high dose thoracic irradiation to investigate lung fibrosis and candidate modulators, a systematic radiobiological characterization of RILF mouse model is urgently needed to compare relative biological effectiveness (RBE) of particle irradiation with protons, helium-, carbon and oxygen ions now available at HIT...
November 7, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/29115826/experimental-computational-synergy-for-selective-pd-ii-catalyzed-c-h-activation-of-aryl-and-alkyl-groups
#15
Yun-Fang Yang, Xin Hong, Jin-Quan Yu, K N Houk
C-H activation and functionalization are on the forefront of modern synthetic chemistry. Imagine if any C-H bond of a molecule could be converted to a C-X bond, where X is the target functionality-this would alter the synthetic blueprints for complex target molecules since it would provide novel disconnections in retrosynthetic analysis. Collaborations between many experimental and computational groups have led to rapid developments of new C-H functionalization methods. Our groups represent an example of this; we were brought together as part of the NSF-supported Center for Selective C-H Functionalization...
November 8, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29114615/risk-of-carotid-blowout-after-reirradiation-with-particle-therapy
#16
Jon Espen Dale, Silvia Molinelli, Elisa Ciurlia, Mario Ciocca, Maria Bonora, Viviana Vitolo, Alfredo Mirandola, Stefania Russo, Roberto Orecchia, Olav Dahl, Piero Fossati
Purpose: Carotid blowout (CB) is a serious complication in retreatment of neoplasms in the head and neck (H&N) region. Rates seem to increase in hypofractionated or accelerated hyperfractionated regimens. In this study, we investigate the CB rate and the cumulative doses received by the carotid artery (CA) in a cohort of patients who were reirradiated at CNAO with particle therapy in the H&N region. Methods and materials: The dosimetric information, medical records, and tumor characteristics of 96 patients were analyzed...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29112810/electronic-effects-on-room-temperature-gas-phase-c-h-bond-activations-by-cluster-oxides-and-metal-carbides-the-methane-challenge
#17
Helmut Schwarz, Sason Shaik, Jilai Li
This Perspective discusses a story of one molecule (methane), a few metal-oxide cationic clusters (MOCCs), dopants, metal-carbide cations, oriented-electric fields (OEFs), and a dizzying mechanistic landscape of methane activation! One mechanism is hydrogen atom transfer (HAT), which occurs whenever the MOCC possesses a localized oxyl radical (M-O(•)). Whenever the radical is delocalized e.g., in [MgO]n(•+) the HAT barrier increases due to the penalty of radical localization. Adding a dopant (Ga2O3) to [MgO]2(•+) localizes the radical and HAT transpires...
November 7, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29111963/endophytic-fungal-production-rates-of-volatile-organic-compounds-are-highest-under-microaerophilic-conditions
#18
Heidi R Schoen, Walter Berk Knighton, Brent M Peyton
Volatile organic compound (VOC) production from an endophytic fungus was quantified at four oxygen concentrations (0, 1, 13 and 21 %) throughout culture growth phases. The filamentous fungus, a Nodulisporium sp. (designated TI-13), was grown in a solid-state reactor with an agricultural byproduct, beet pulp, as the solid substrate. The VOCs, with potential applications as biofuels, natural flavour compounds and bioactive mixtures, were measured with a recently introduced platinum catalyst and proton transfer reaction mass spectrometry quantification system...
November 7, 2017: Microbiology
https://www.readbyqxmd.com/read/29102642/adsorptive-removal-of-indole-and-quinoline-from-model-fuel-using-adenine-grafted-metal-organic-frameworks
#19
Mithun Sarker, Ji Yoon Song, Ah Rim Jeong, Kil Sik Min, Sung Hwa Jhung
A highly porous metal-organic framework (MOF), MIL-101, was modified for the first time with the nucleobase adenine (Ade) by grafting onto the MOF. The Ade-grafted MOF, Ade-MIL-101, was further protonated to obtain P-Ade-MIL-101, and these MOFs were utilized to remove nitrogen-containing compounds (NCCs) (such as indole (IND) and quinoline (QUI)) from a model fuel by adsorption. These functionalized MOFs exhibited remarkable adsorption performance for NCCs compared with that shown by commercial activated carbon (AC) and pristine MIL-101, even though the porosities of the functionalized-MOFs were lower than that of pristine MIL-101...
October 28, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29099943/genetic-labeling-of-car4-expressing-cells-reveals-subpopulations-of-type-iii-taste-cells
#20
Kristina Lossow, Irm Hermans-Borgmeyer, Maik Behrens, Wolfgang Meyerhof
Carbonic anhydrases form an enzyme family of 16 members, which reversibly catalyze the hydration of carbon dioxide to bicarbonate and protons. In lung, kidney, and brain, presence of carbonic anhydrases is associated with protons and bicarbonate transport in capillary endothelium of lung, reabsorption of bicarbonate in proximal renal tubules, and extracellular buffering. In contrast, their role in taste is less clear. Recently, carbonic anhydrase IV expression was detected in sour-sensing presynaptic taste cells and was associated with the taste of carbonation, yet the precise role and cell population remained uncertain...
October 31, 2017: Chemical Senses
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