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Oxygen kinetics

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https://www.readbyqxmd.com/read/28738154/modifying-surface-chemistry-of-metal-oxides-for-boosting-dissolution-kinetics-in-water-by-liquid-cell-electron-microscopy
#1
Yue Lu, Jiguo Geng, Kuan Wang, Wei Zhang, Wenqiang Ding, Zhenhua Zhang, Shaohua Xie, Hongxing Dai, Fu-Rong Chen, Manling Sui
Dissolution of metal oxides is fundamentally important for understanding mineral evolution and micromachining oxide functional materials. In general, dissolution of metal oxides is a slow and inefficient chemical reaction. Here, by introducing oxygen deficiencies to modify the surface chemistry of oxides, we can boost the dissolution kinetics of metal oxides in water, as in situ demonstrated in a liquid environmental transmission electron microscope (LETEM). The dissolution rate constant significantly increases by 16-19 orders of magnitude, equivalently a reduction of 0...
July 24, 2017: ACS Nano
https://www.readbyqxmd.com/read/28737918/reactive-inelastic-and-dissociation-processes-in-collisions-of-atomic-oxygen-with-molecular-nitrogen
#2
Fabrizio Esposito, Iole Armenise
We report the results of detailed calculations of reactive, inelastic and dissociative processes in collisions of atomic oxygen with molecular nitrogen in their respective electronic ground states. Cross sections are calculated as a function of collision energy in the range 0.001-10eV, considering the whole rovibrational ladder. Some problems related to the vibrational energy levels of the asymptotes of 3A" and 3A' potential energy surfaces used in this work are solved by an appropriate scaling at the level of cross sections...
July 24, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28735650/prognostic-utility-of-neuroinjury-biomarkers-in-post-out-of-hospital-cardiac-arrest-ohca-patient-management
#3
S S Gul, K W Huesgen, K K Wang, K Mark, J A Tyndall
Despite aggressive intervention, patients who survive an out-of-hospital cardiac arrest (OHCA) generally have very poor prognoses, with nationwide survival rates of approximately 10-20%. Approximately 90% of survivors will have moderate to severe neurological injury ranging from moderate cognitive impairment to brain death. Currently, few early prognostic indicators are considered reliable enough to support patients' families and clinicians' in their decisions regarding medical futility. Blood biomarkers of neurological injury after OHCA may be of prognostic value in these cases...
August 2017: Medical Hypotheses
https://www.readbyqxmd.com/read/28735401/determination-of-enzymes-associated-with-sulfite-toxicity-in-plants-kinetic-assays-for-so-apr-sir-and-in-gel-sir-activity
#4
Galina Brychkova, Assylay Kurmanbayeva, Aizat Bekturova, Inna Khozin, Dominic Standing, Dmitry Yarmolinsky, Moshe Sagi
The amino acid cysteine plays a major role in plant response to abiotic stress by being the donor of elemental sulfur for the sulfuration of the molybdenum cofactor, otherwise the last step of ABA biosynthesis, the oxidation of abscisic aldehyde, is inactivated. Additionally, cysteine serves as a precursor for the biosynthesis of glutathione, the reactive oxygen species scavenger essential for redox status homeostasis during stress. Cysteine is generated by the sulfate reductive pathway where sulfite oxidase (SO; EC 1...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28734543/crouch-severity-is-a-poor-predictor-of-elevated-oxygen-consumption-in-cerebral-palsy
#5
Katherine M Steele, Benjamin R Shuman, Michael H Schwartz
Children with cerebral palsy (CP) expend more energy to walk compared to typically-developing peers. One of the most prevalent gait patterns among children with CP, crouch gait, is often singled out as especially exhausting. The dynamics of crouch gait increase external flexion moments and the demand on extensor muscles. This elevated demand is thought to dramatically increase energy expenditure. However, the impact of crouch severity on energy expenditure has not been investigated among children with CP. We evaluated oxygen consumption and gait kinematics for 573 children with bilateral CP...
July 5, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28734291/relaxation-dynamics-and-transformation-kinetics-of-deeply-supercooled-water-temperature-pressure-doping-and-proton-deuteron-isotope-effects
#6
Sonja Lemke, Philip H Handle, Lucie J Plaga, Josef N Stern, Markus Seidl, Violeta Fuentes-Landete, Katrin Amann-Winkel, Karsten W Köster, Catalin Gainaru, Thomas Loerting, Roland Böhmer
Above its glass transition, the equilibrated high-density amorphous ice (HDA) transforms to the low-density pendant (LDA). The temperature dependence of the transformation is monitored at ambient pressure using dielectric spectroscopy and at elevated pressures using dilatometry. It is found that near the glass transition temperature of deuterated samples, the transformation kinetics is 300 times slower than the structural relaxation, while for protonated samples, the time scale separation is at least 30 000 and insensitive to doping...
July 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28734248/effects-of-constructed-wetland-design-on-ibuprofen-removal-a-mesocosm-scale-study
#7
Liang Zhang, Tao Lv, Yang Zhang, Otto R Stein, Carlos A Arias, Hans Brix, Pedro N Carvalho
This study aimed to investigate the effects of constructed wetland design (unsaturated, saturated and aerated saturated) and plant species (Juncus, Typha, Berula, Phragmites and Iris) on the mass removal and removal kinetics of the pharmaceutical ibuprofen. Planted systems had higher ibuprofen removal rates (29%-99%) than in the unplanted ones (15%-85%) in all designs. The use of forced aeration improved ibuprofen removal only in the unplanted mesocosms. In general, ibuprofen removal followed an area-based first-order removal kinetics model with removal rate coefficients (kA) varying between 3 and 35cm/d...
July 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28732965/facile-and-cost-effective-preparation-of-pva-modified-calcium-carbonate-nanocomposites-via-ultrasonic-irradiation-application-in-adsorption-of-heavy-metal-and-oxygen-permeation-property
#8
Shadpour Mallakpour, Elham Khadem
This work is focused on the fabrication and determination of physicochemical behaviors of new poly(vinyl alcohol) (PVA) nanocomposites (NCs) containing various contents of calcium carbonate (CC) nanoparticles modified with γ-aminopropyl triethoxy silane (ATS) (henceforth designated as CC-ATS) which could be a crucial treatment for their application as gas barrier to O2 gas and uptake of metal ions in waste waters. Samples were produced through the solution casting method under ultrasound irradiation. Thermal and mechanical performances were also evaluated for all ultrasonically synthesized nanocomposites and the results indicated that thermal and mechanical stability are dramatically enhanced by addition of a small amount of modified CC-ATS within PVA up to 5wt% and higher amounts has low effect on the composite properties...
November 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28732443/a-first-principles-study-on-o2-adsorption-and-dissociation-processes-over-rh-100-and-rh-111-surfaces
#9
Lu Tan, Liangliang Huang, Qi Wang, Yingchun Liu
Through DFT calculations, a systematic description of O2 adsorption and dissociation processes over Rh(100) and Rh(111) surfaces has been provided. The dominance of parallel orientation in molecularly adsorbed states and during the impinging processes has been identified, along with the explicit adsorption configurations and preferred impinging trajectories on both surfaces. The dissociation of O2 is found to occur either by precursor mediated adsorption or by direct dissociation. O2 in initial precursor state dissociates facilely on Rh(100) but a little harder on Rh(111) by going through a two-step process...
July 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28731691/singlet-oxygen-photophysics-in-liquid-solvents-converging-on-a-unified-picture
#10
Mikkel Bregnhøj, Michael Westberg, Boris F Minaev, Peter R Ogilby
Singlet oxygen, O2(a(1)Δg), the lowest excited electronic state of molecular oxygen, is an omnipresent part of life on earth. It is readily formed through a variety of chemical and photochemical processes, and its unique reactions are important not just as a tool in chemical syntheses but also in processes that range from polymer degradation to signaling in biological cells. For these reasons, O2(a(1)Δg) has been the subject of intense activity in a broad distribution of scientific fields for the past ∼50 years...
July 21, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28731326/oxygen-partial-pressure-during-pulsed-laser-deposition-deterministic-role-on-thermodynamic-stability-of-atomic-termination-sequence-at-srruo3-batio3-interface
#11
Yeong Jae Shin, Lingfei Wang, Yoonkoo Kim, Ho-Hyun Nahm, Daesu Lee, Jeong Rae Kim, Sang Mo Yang, Jong-Gul Yoon, Jin-Seok Chung, Miyoung Kim, Seo Hyoung Chang, Tae Won Noh
With recent trends on miniaturizing oxide-based devices, the need for atomic-scale control of surface/interface structures by pulsed laser deposition (PLD) has increased. In particular, realizing uniform atomic termination at the surface/interface is highly desirable. However, a lack of understanding on the surface formation mechanism in PLD has limited a deliberate control of surface/interface atomic stacking sequences. Here, taking the prototypical SrRuO3/BaTiO3/SrRuO3 (SRO/BTO/SRO) heterostructure as a model system, we investigated the formation of different interfacial termination sequences (BaO-RuO2 or TiO2-SrO) with oxygen partial pressure (PO2) during PLD...
July 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28730698/boar-sperm-quality-after-supplementation-of-diets-with-omega-3-polyunsaturated-fatty-acids-extracted-from-microalgae
#12
Y T Andriola, F Moreira, E Anastácio, F A Camelo, A C Silva, A S Varela, S M M Gheller, K L Goularte, C D Corcini, T Lucia
This study evaluated effects of diet supplementation with omega-3 polyunsaturated fatty acids (PUFA) from microalgae on boar sperm quality. Two groups of boars (n = 3 each) were fed during 75 days either a commercial diet (control), or the same diet supplemented with omega-3 PUFA from the heterotrophic microalgae Schizochytrium sp. (120 g/kg). Sixteen ejaculates were collected per boar. Some sperm kinetics parameters were inferior for supplemented than for control boars (p < .05): distance average path; distance in both curved and straight line; velocity average path, velocity in both curved and straight line; and amplitude of lateral head displacement...
July 21, 2017: Andrologia
https://www.readbyqxmd.com/read/28729534/uv-activated-zno-films-on-a-flexible-substrate-for-room-temperature-o2-and-h2o-sensing
#13
Christopher B Jacobs, Artem B Maksov, Eric S Muckley, Liam Collins, Masoud Mahjouri-Samani, Anton Ievlev, Christopher M Rouleau, Ji-Won Moon, David E Graham, Bobby G Sumpter, Ilia N Ivanov
We demonstrate that UV-light activation of polycrystalline ZnO films on flexible polyimide (Kapton) substrates can be used to detect and differentiate between environmental changes in oxygen and water vapor. The in-plane resistive and impedance properties of ZnO films, fabricated from bacteria-derived ZnS nanoparticles, exhibit unique resistive and capacitive responses to changes in O2 and H2O. We propose that the distinctive responses to O2 and H2O adsorption on ZnO could be utilized to statistically discriminate between the two analytes...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28729509/experimentally-realized-mechanochemistry-distinct-from-force-accelerated-scission-of-loaded-bonds
#14
Sergey Akbulatov, Yancong Tian, Zhen Huang, Timothy J Kucharski, Qing-Zheng Yang, Roman Boulatov
Stretching polymer chains accelerates dissociation of a variety of internal covalent bonds, to an extent that correlates well with the force experienced by the scissile bond. Recent theory has also predicted scenarios in which applied force accelerates dissociation of unloaded bonds and kinetically strengthens strained bonds. We report here unambiguous experimental validation of this hypothesis: Detailed kinetic measurements demonstrate that stretching phosphotriesters accelerates dissociation of the unloaded phosphorus-oxygen bond orthogonal to the pulling axis, whereas stretching organosiloxanes inhibits dissociation of the aligned loaded silicon-oxygen bonds...
July 21, 2017: Science
https://www.readbyqxmd.com/read/28728976/effect-of-alkylaminophenols-on-growth-inhibition-and-apoptosis-of-bone-cancer-cells
#15
Phuong Doan, Tien Nguyen, Olli Yli-Harja, Nuno R Candeias, Meenakshisundaram Kandhavelu
In this work, we report the anticancer properties of a series of 11 chemically synthesized alkylaminophenols against human osteosarcoma U2OS tumor cell line. Several assays including cytotoxicity, inhibitor kinetic study, cell migration, Annexin-V/PI double staining, reactive oxygen species (ROS) and caspase 3/7 assays were conducted on this cell line. Cytotoxic 2-((3,4-dihydroquinolin-1(2H)-yl)(p-tolyl)methyl)phenol was determined to have an IC50 value of 36.6μM against U2OS cells and it also inhibits the cell growth in time-dependent manner...
July 17, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28726960/robust-triplet-triplet-annihilation-photon-upconversion-by-efficient-oxygen-scavenging
#16
Damir Dzebo, Kasper Moth-Poulsen, Bo Albinsson
We hereby present a simple method for reducing the effect of oxygen quenching in Triplet-Triplet Annihilation Upconversion (TTA-UC) systems. A number of commercially available thioethers and one thiol have been tested as singlet oxygen scavengers. Recording of the upconverted emission from a well-studied PdOEP (sensitizer)-DPA (annihilator/emitter) couple has been made over time with steady-state excitation capturing the steady-state kinetics of the TTA-UC process as the solubilized oxygen is depleted by reaction with the scavengers...
July 20, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28726229/monitoring-and-modeling-4-chlorophenol-biodegradation-kinetics-by-phenol-acclimated-activated-sludge-by-using-open-respirometry
#17
Cintia C Lobo, Nora C Bertola, Edgardo M Contreras, Noemí E Zaritzky
The aim of this study was to analyze the mechanisms, stoichiometry, and stability of 4-chlorophenol (4CP) biodegradation kinetics by phenol-acclimated activated sludge using open respirometry. While the removal of 4CP was higher than 98%, the removal of chemical oxygen demand (COD) ranged between 69 and 79% due to the accumulation of an intermediate metabolite. The value obtained from respirometric profiles for the stoichiometric ratio of O2 to 4CP (YO2/4CP) was 1.95 ± 0.04 mol of oxygen consumed per mol of 4CP removed...
July 20, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28725263/modeling-and-simulation-of-the-redox-regulation-of-the-metabolism-in-escherichia-coli-at-different-oxygen-concentrations
#18
Yu Matsuoka, Hiroyuki Kurata
BACKGROUND: Microbial production of biofuels and biochemicals from renewable feedstocks has received considerable recent attention from environmental protection and energy production perspectives. Many biofuels and biochemicals are produced by fermentation under oxygen-limited conditions following initiation of aerobic cultivation to enhance the cell growth rate. Thus, it is of significant interest to investigate the effect of dissolved oxygen concentration on redox regulation in Escherichia coli, a particularly popular cellular factory due to its high growth rate and well-characterized physiology...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28721747/faster-v%C3%AC-o2-kinetics-after-priming-exercises-of-different-duration-but-same-fatigue
#19
Felipe Mattioni Maturana, Arthur Peyrard, John Temesi, Guillaume Y Millet, Juan M Murias
This study compared the responses of two priming exercises of similar fatigue on the adjustment of the oxygen uptake time constant (τV̇O2) in cycling. Ten healthy young adults (25 ± 3 yr) performed: three step transitions from a 20-W baseline to the power output (PO) below the gas exchange threshold (MOD, MODPRE); a 3-min bout (P3MIN) at 90% of peak PO (POpeak), followed by MOD (MOD3MIN); and a 6-min bout (P6MIN) at 80% of POpeak, followed by MOD (MOD6MIN). The O2 supply-to-O2 demand ([HHb]/V̇O2) ratio was calculated for MODPRE, MOD3MIN, and MOD6MIN...
July 19, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28718625/controlling-the-interfacial-environment-in-the-electrosynthesis-of-mnox-nanostructures-for-high-performance-oxygen-reduction-evolution-electrocatalysis
#20
Pooya Hosseini-Benhangi, Chun Haow Kung, Akram Alfantazi, Elod L Gyenge
High-performance, non-precious metal bifunctional electrocatalysts for oxygen reduction and evolution reactions (ORR and OER, respectively) are of great importance for rechargeable metal-air batteries and regenerative fuel cells. A comprehensive study based on statistical design of experiments is presented to investigate and optimize the surfactant-assisted structure and the resultant bifunctional ORR/OER activity of anodically deposited manganese oxide (MnOx) catalysts. Three classes of surfactants are studied: anionic (sodium dodecyl sulfate, SDS), non-ionic (t Octylphenoxypolyethoxyethanol, Triton X-100) and cationic (cetyltrimethylammonium bromide, CTAB)...
July 18, 2017: ACS Applied Materials & Interfaces
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