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Oxygen kinetics

D Schleier, P Constantinidis, N Faßheber, I Fischer, G Friedrichs, P Hemberger, E Reusch, B Sztáray, K Voronova
The kinetics of the combustion-relevant reaction of the allyl radical, a-C3H5, with molecular oxygen has been studied in a flow tube reactor at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source storage ring, using the CRF-PEPICO (Combustion Reactions Followed by Photoelectron Photoion Coincidence Spectroscopy) setup. The ability to measure threshold photoelectron spectra enables a background-free detection of reactive species as well as an isomer-specific analysis of reaction products. Allyl was generated by direct photodissociation of allyl iodide at 266 nm and 213 nm and indirectly by the reaction of propene with Cl atoms, which were generated by photolysis from oxalyl chloride at 266 nm...
January 17, 2018: Physical Chemistry Chemical Physics: PCCP
Jessica G Swallow, Ja Kyung Lee, Thomas Defferriere, Gareth Martin Hughes, Shilpa N Raja, Harry L Tuller, Jamie H Warner, Krystyn J Van Vliet
Thin film non-stoichiometric oxides enable many high temperature applications including solid oxide fuel cells, actuators, and catalysis. Large concentrations of point defects (particularly, oxygen vacancies) enable fast ionic conductivity or gas exchange kinetics in these materials, but also manifest as coupling between lattice volume and chemical composition. This chemical expansion may be either detrimental or useful, especially in thin film devices that may exhibit enhanced performance through strain engineering or decreased operating temperatures...
January 16, 2018: ACS Nano
Muadh Hussain, Vanessa Zimmermann, Sjoerd J L van Wijk, Simone Fulda
Mouse embryonic fibroblasts (MEFs) have extensively been used to study necroptosis, a recently identified form of programmed cell death. However, very little is yet known about the role of necroptosis and its regulation by reactive oxygen species (ROS) in cell types naturally exposed to high oxygen levels such as mouse lung fibroblasts (MLFs). Here, we discover that MLFs are highly susceptible to undergo necroptosis in a ROS-dependent manner upon exposure to a prototypic death receptor-mediated necroptotic stimulus, i...
January 11, 2018: Biochemical Pharmacology
Nicholas M Beltz, Fabiano Amorim, Ann L Gibson, Jeffrey M Janot, Len Kravitz, Christine M Mermier, Nathan Cole, Terence A Moriarty, Tony P Nunez, Sam Trigg, Lance Dalleck
PURPOSE: Recent examinations have shown lower maximal oxygen uptake (VO2max) during traditional ramp (RAMP) compared to self-paced (SPV) graded exercise testing (GXT) attributed to differences in cardiac ouput. The current study examined the differences in hemodyamic and metabolic responses between RAMP and SPV during treadmill exercise. METHODS: Sixteen recreationally trained men (23.7±3.0 yrs) completed two separate treadmill GXT protocols. SPV consisted of five 2-min stages (10 min total) of increasing speed clamped by the Borg RPE6-20 scale...
January 15, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Yingpu Bi, Beibei Zhang, Lei Wang, Yajun Zhang, Yong Ding
Photoelectrochemical (PEC) water splitting is a promising method for storing solar energy in the form of hydrogen fuel, but greatly hindered by the sluggish kinetics of the oxygen evolution reaction (OER). Herein, a facile solution impregnation method is developed for growing highly crystalline β-FeOOH nanolayers with ultrathin thickness (2 nm) and abundant oxygen vacancies on BiVO4 photoanodes, which exhibited a remarkable photocurrent density of 4.3 mA cm-2 at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1...
January 14, 2018: Angewandte Chemie
Mohamed E M Ali, Azza M Abd El-Aty, Mohamed I Badawy, Rizka K Ali
Pharmaceutical compounds are considered emerging environmental pollutants that have a potential harmful impact on environment and human health. In this study, the biomass of alga (Scenedesmus obliquus) was modified using alkaline solution, and used for the biosorption of tramadol (TRAM) and other pharmaceuticals. The adsorption kinetics and isotherms were investigated. The obtained results reveal high adsorption capacity of tramadol over modified algal biomass (MAB) after 45min with removal percentage of 91%...
January 11, 2018: Ecotoxicology and Environmental Safety
Almudena Marrufo-Curtido, Vanesa Carrascón, Mónica Bueno, Vicente Ferreira, Ana Escudero
The rates at which wine consumes oxygen are important technological parameters for whose measurement there are not accepted procedures. In this work, volumes of 8 wines are contacted with controlled volumes of air in air-tight tubes containing oxygen-sensors and are further agitated at 25 °C until O2 consumption is complete. Three exposure levels of O2 were used: low (10 mg/L) and medium or high (18 or 32 mg/L plus the required amount to oxidize all wine SO2). In each oxygen level, 2-4 independent segments following pseudo-first order kinetics were identified, plus an initial segment at which wine consumed O2 very fast...
May 15, 2018: Food Chemistry
L Schiavo, S De Nicola, G Carotenuto
Pd(0) is able to catalyze oxygen-involving reactions because of its capability to convert molecular oxygen to the very reactive atomic form. Consequently, the embedding of a little amount of Pd(0) clusters in polymeric phases can be technologically exploited to enhance the incineration kinetic of these polymers. The effect of nanostructuration on the Pd(0) catalytic activity in the polymer incineration reaction has been studied using poly(N-vinyl-2-pyrrolidone) ([Formula: see text] = 10,000 gmol-1) as polymeric model system...
January 11, 2018: Nanoscale Research Letters
Zahra Derakhshan, Amir Hossein Mahvi, Mohammad Taghi Ghaneian, Seyed Mohammad Mazloomi, Mohammad Faramarzian, Mansooreh Dehghani, Hossein Fallahzadeh, Saeed Yousefinejad, Enayat Berizi, Mohammad Hassan Ehrampoush, Shima Bahrami
In this study, an anaerobic moving bed biofilm reactor (AMBBR) was designed to biodegrade atrazine under mesophilic (32 °C) condition and then it was evaluated for approximately 1 year. After biofilm formation, acclimation, and enrichment of microbial population within the bioreactor, the effect of various operation conditions such as changes in the concentration of influent atrazine and sucrose, hydraulic retention time (HRT), and salinity on the removal of atrazine and chemical oxygen demand (COD) were studied...
January 8, 2018: Journal of Environmental Management
Boyli Ghosh, Ambar Banerjee, Ankan Paul
Oxidation of non-metallic singlet molecules by oxygen has its own share of intricacies. Herein using DFT and ab inito techniques we shed light on the mechanistic details of the aerial oxidation of NHC stabilized diphosphorus complex. This particular oxidation process is known to produce an unexpected P-P bond containing diphosphorus tetroxide complex instead of the more thermodynamically stable oxobridged (P-O-P) compound. Our findings suggest that, the P-P bond containing less stabilized species is a kinetically controlled product (KCP) and obtained due to the presence of lower lying transition states (TSs) in the pathway leading to its formation, as compared to the higher lying corresponding Minimum Energy Crossing Points (MECPs) present in the pathway involved in the formation of the oxobridged species, the thermodynamically controlled product (TCP)...
January 11, 2018: Chemistry: a European Journal
David Bajnai, Jens Fiebig, Adam Tomašových, Sara Milner Garcia, Claire Rollion-Bard, Jacek Raddatz, Niklas Löffler, Cristina Primo-Ramos, Uwe Brand
Brachiopod shells are the most widely used geological archive for the reconstruction of the temperature and the oxygen isotope composition of Phanerozoic seawater. However, it is not conclusive whether brachiopods precipitate their shells in thermodynamic equilibrium. In this study, we investigated the potential impact of kinetic controls on the isotope composition of modern brachiopods by measuring the oxygen and clumped isotope compositions of their shells. Our results show that clumped and oxygen isotope compositions depart from thermodynamic equilibrium due to growth rate-induced kinetic effects...
January 11, 2018: Scientific Reports
Kyle Swovick, Kevin A Welle, Jennifer Hryhorenko, Andrei Seluanov, Vera Gorbunova, Sina Ghaemmaghami
The constitutive process of protein turnover plays a key role in maintaining cellular homeostasis. Recent technological advances in mass spectrometry have enabled the measurement of protein turnover kinetics across the proteome. However, it is not known if turnover kinetics of individual proteins are highly conserved or if they have evolved to meet the physiological demands of individual species. Here, we conducted systematic analyses of proteome turnover kinetics in primary dermal fibroblasts isolated from eight different rodent species...
January 10, 2018: Molecular & Cellular Proteomics: MCP
Xiqian Jiang, Lingfei Wang, Shaina Laufer Carroll, Jianwei Chen, Meng C Wang, Jin Wang
SIGNIFICANCE: The concentrations of reactive oxygen/nitrogen species (ROS/RNS) are critical to various biochemical processes. Small molecule fluorescent probes have been widely used to detect and/or quantify ROS/RNS in many redox biology studies and serve as an important complementary to protein-based sensors with unique applications. Recent Advances: New sensing reactions have emerged in probe development allowing more selective and quantitative detection of ROS/RNS, especially in live cells...
January 10, 2018: Antioxidants & Redox Signaling
Markus Antonietti, Alexandr Savateev
Water splitting to its elements, either by electrochemistry or by solar light, is among the most covered areas in nanostructured functional materials. This personal account article analyzes potential downstream translation problems and reviews alternative chemistries with a potential higher return. Liberation of oxygen for accepting the holes is a kinetically demanding half reaction afflicted with kinetic hindrances and high overpotentials, while at the same time no marketable value is created (atmospheric oxygen is free to use)...
January 10, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Alexandra T P Carvalho, Daniel F A R Dourado, Timofey Skvortsov, Miguel de Abreu, Lyndsey J Ferguson, Derek J Quinn, Thomas S Moody, Meilan Huang
Phenylacetone monooxygenase is the most stable and thermo-tolerant member of the Baeyer-Villiger monooxygenases family, and therefore it is an ideal candidate for the synthesis of industrially relevant ester or lactone compounds. However, its limited substrate scope has largely limited its industrial applications. Linear substrates are interesting from an industrial point of view, it is thus necessary to identify the essential spatial requirement for achieving high conversions for non-native linear substrates...
January 10, 2018: Physical Chemistry Chemical Physics: PCCP
Xingxing Cheng, Ming Zhang, Zhiqiang Wang, Guiying Xu, Chunyuan Ma
Thermal degradation of sewage sludge disposal is attracting more attention due to the increase in municipal wastewater treatment. In this work the performance of the thermochemical processes of sewage sludge at different oxygen concentrations was investigated by thermogravimetric (TG) and Fourier transform infrared analysis (FTIR) study. The oxygen concentrations were varied systematically from 0 to 20%, representing heating process from pyrolysis to full combustion. The evolutions of surface functional groups in these processes were also investigated by in situ diffuse reflectance infrared Fourier transform spectra (DRIFT), which helped to understand the reaction mechanism during the thermal degradation, especially when the reaction conditions were different...
January 6, 2018: Waste Management
Anthony Pinon, Michèle Vialette
Water, a frequent vehicle for the transmission of viruses, may permit their survival, but many environmental factors will have an adverse effect on the viral population. Risk evaluation requires identification of these factors and assessment of the inactivation rate of infectious viruses. A higher temperature means a faster reduction of the viral population, as do increased sunlight, higher antimicrobial concentration, or higher oxygen levels. Another documented impact is linked to the presence of indigenous microbial populations: virus survival is higher in sterile water...
January 10, 2018: Intervirology
Wei Wang, Ye Wang, Gui-Chang Wang
Although the reaction mechanism of syngas on Fe or Cu(Pd)-doped Fe has been studied extensively both experimentally and theoretically, the systematic prediction of the catalytic activity and selectivity for the formation of ethanol at the molecular level has not been reported to the best of our knowledge. In our present work, density functional theory calculations were performed to investigate the reaction mechanisms of the synthesis of ethanol, methanol, and methane from syngas over bimetallic Cu/Fe and Pd/Fe catalysts...
January 9, 2018: Physical Chemistry Chemical Physics: PCCP
Tricia L Meyer, Ryan Jacobs, Dongkyu Lee, Lu Jiang, John W Freeland, Changhee Sohn, Takeshi Egami, Dane Morgan, Ho Nyung Lee
Oxygen defect control has long been considered an important route to functionalizing complex oxide films. However, the nature of oxygen defects in thin films is often not investigated beyond basic redox chemistry. One of the model examples for oxygen-defect studies is the layered Ruddlesden-Popper phase La2-xSr x CuO4-δ (LSCO), in which the superconducting transition temperature is highly sensitive to epitaxial strain. However, previous observations of strain-superconductivity coupling in LSCO thin films were mainly understood in terms of elastic contributions to mechanical buckling, with minimal consideration of kinetic or thermodynamic factors...
January 8, 2018: Nature Communications
Jie Qiao, Lixin Ma, Justine Roth, Yamin Li, Yi Liu
Numerous studies have shown that nitric oxide (NO) interacts with human cyclooxygenase (COX); however, conflicting results exist with respect to their interactions. Herein, recombinant human COX-1 and COX-2 were prepared and treated with NO donors individually under anaerobic and aerobic conditions. The S-nitrosylation detection and subsequent kinetic investigations into the arachidonic acid (AA) oxidation of COX enzymes indicate that NO S-nitrosylates both COX-1 and COX-2 in an oxygen-dependent manner, but enhances only the dioxygenase activity of COX-2...
January 8, 2018: Organic & Biomolecular Chemistry
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