keyword
MENU ▼
Read by QxMD icon Read
search

Oxygen kinetics

keyword
https://www.readbyqxmd.com/read/28430375/electrochemical-water-oxidation-catalyzed-by-an-in-situ-generated-%C3%AE-co-oh-2-film-on-zeolite-y-surface
#1
Samar Kumar Das, Suranjana Bose, Joyashish Debgupta, Rani Ramsundar
The design and synthesis of an efficient and robust water oxidation catalyst (WOC) with inexpensive materials remain an important challenge in the context of 'artificial photosynthesis'. Herein, we report a simple but unique technique to generate in situ a thin-film of α-Co(OH)2 on the surface of zeolite-Y [hereafter named as Y-α-Co(OH)2] that acts as an efficient and stable catalyst for electrochemical water oxidation in an alkaline pH. Catalyst Y-α-Co(OH)2 is so stable that it retains its catalytic activity even after 2000 cyclic voltammetric cycles of water oxidation...
April 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28429831/one-step-fabrication-of-monolithic-electrodes-comprising-co9s8-particles-supported-on-cobalt-foam-for-efficient-and-durable-oxygen-evolution-reaction
#2
Dehua Xiong, Qingqing Zhang, Sitaramanjaneya Mouli Thalluri, Junyuan Xu, Wei Li, Xiuli Fu, Lifeng Liu
We report a very easy and cost-effective approach to the fabrication of monolithic Co9S8 water oxidation electrodes (Co@Co9S8), which is fabricated by one-step hydrothermal treatment of commercially available cobalt foam in the presence of thiourea. The morphology, crystal structure, microstructure, and composition of as-fabricated Co@Co9S8 electrodes are examined using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS), and their electrochemical properties are investigated by cyclic voltammetry (CV), chronopotentiometry (CP), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS)...
April 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28427623/degradation-of-reactive-blue-13-using-hydrodynamic-cavitation-effect-of-geometrical-parameters-and-different-oxidizing-additives
#3
Sunil Rajoriya, Swapnil Bargole, Virendra Kumar Saharan
Decolorization of reactive blue 13 (RB13), a sulphonated azo dye, was investigated using hydrodynamic cavitation (HC). The aim of research article is to check the influence of geometrical parameters (total flow area, the ratio of throat perimeter to its cross-sectional area, throat shape and size, etc.) and configuration of the cavitating devices on decolorization of RB13 in aqueous solution. For this purpose, eight cavitating devices i.e. Circular and slit venturi, and six orifice plates having different flow area and perimeter were used in the present work...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28426244/piperine-triggers-apoptosis-of-human-oral-squamous-carcinoma-through-cell-cycle-arrest-and-mitochondrial-oxidative-stress
#4
Sahabjada Siddiqui, Md Sultan Ahamad, Asif Jafri, Mohd Afzal, Md Arshad
Piperine is a nitrogenous pungent substance exhibiting multifunctional pharmacological properties. However, the mechanism underlying its anticancer potential is not well elucidated in human oral squamous carcinoma (KB) cell line. The anticancer potential of piperine was evaluated through potent biomarkers viz. reactive oxygen species (ROS), cellular apoptosis, and loss of mitochondrial membrane potential (MMP). In addition, cell cycle kinetics and caspases-3 activity were also carried out to confirm anticancer activity of piperine...
April 20, 2017: Nutrition and Cancer
https://www.readbyqxmd.com/read/28425293/cosensitized-porphyrin-system-for-high-performance-solar-cells-with-tof-sims-analysis
#5
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yi-Tao Long, He Tian, Wei-Hong Zhu
Up to date, development of organic sensitizers has been predominately focused on light harvesting, HOMO and LUMO energy levels, and electron transferring process. In contrast, their adsorption mode as well as dynamic loading behaviour onto nanoporous TiO2 is rarely considered. Herein we have employed the time of flight secondary ion mass spectrometry (TOF-SIMS) to take insight into the competitive dye adsorption mode and kinetics in cosensitized porphyrin system. Using the novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well compared with two different anchoring groups such as benzoic acid and cyanoacrylic acid...
April 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28425134/record-broken-a-copper-peroxide-complex-with-enhanced-stability-and-faster-hydroxylation-catalysis
#6
Sonja Herres-Pawlis, Patricia Liebhäuser, Kristina Keisers, Alexander Hoffmann, Thomas Schnappinger, Isabella Sommer, Anne Thoma, Claudia Wilfer, Roland Schoch, Kai Stührenberg, Matthias Bauer, Maximilian Dürr, Ivana Ivanovic-Burmazovic
Tyrosinase model systems pinpoint pathways to translate nature´s synthetic abilities into useful synthetic catalysts. Mostly, they use N-donor ligands which mimic the histidine residues coordinating the two copper centres. Copper complexes with bis(pyrazolyl)methanes with pyridinyl or imidazolyl moieties are already reported as excellent tyrosinase models. Substitution of the pyridinyl donor results now in the new ligand HC(3 tBuPz)2(4 CO2MePy) which stabilises a room-temperature stable -2:2-peroxide dicopper(II) species upon oxygenation...
April 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28421142/plackett-burman-design-for-rgilcc1-laccase-activity-enhancement-in-pichia-pastoris-concentrated-enzyme-kinetic-characterization
#7
Edwin D Morales-Álvarez, Claudia M Rivera-Hoyos, Ángela M Cardozo-Bernal, Raúl A Poutou-Piñales, Aura M Pedroza-Rodríguez, Dennis J Díaz-Rincón, Alexander Rodríguez-López, Carlos J Alméciga-Díaz, Claudia L Cuervo-Patiño
Laccases are multicopper oxidases that catalyze aromatic and nonaromatic compounds with concomitant reduction of molecular oxygen to water. They are of great interest due to their potential biotechnological applications. In this work we statistically improved culture media for recombinant GILCC1 (rGILCC1) laccase production at low scale from Ganoderma lucidum containing the construct pGAPZαA-GlucPost-Stop in Pichia pastoris. Temperature, pH stability, and kinetic parameter characterizations were determined by monitoring concentrate enzyme oxidation at different ABTS substrate concentrations...
2017: Enzyme Research
https://www.readbyqxmd.com/read/28418215/multichannel-porous-tio2-hollow-nanofibers-with-rich-oxygen-vacancies-and-high-grain-boundary-density-enabling-superior-sodium-storage-performance
#8
Ying Wu, Yu Jiang, Jinan Shi, Lin Gu, Yan Yu
TiO2 as an anode for sodium-ion batteries (NIBs) has attracted much recent attention, but poor cyclability and rate performance remain problematic owing to the intrinsic electronic conductivity and the sluggish diffusivity of Na ions in the TiO2 matrix. Herein, a simple process is demonstrated to improve the sodium storage performance of TiO2 by fabricating a 1D, multichannel, porous binary-phase anatase-TiO2 -rutile-TiO2 composite with oxygen-deficient and high grain-boundary density (denoted as a-TiO2-x /r-TiO2-x ) via electrospinning and subsequent vacuum treatment...
April 18, 2017: Small
https://www.readbyqxmd.com/read/28418073/evolved-changes-in-the-intracellular-distribution-and-physiology-of-muscle-mitochondria-in-high-altitude-native-deer-mice
#9
Sajeni Mahalingam, Grant B McClelland, Graham R Scott
High-altitude natives that have evolved to live in hypoxic environments provide a compelling system to understand how animals can overcome impairments in oxygen availability. We examined whether these include changes in mitochondrial physiology or intracellular distribution that contribute to hypoxia resistance in high-altitude deer mice (Peromyscus maniculatus). Mice from populations native to high- and low-altitudes were born and raised in captivity, and as adults were acclimated to normoxia or hypobaric hypoxia (equivalent to 4,300 m elevation)...
April 18, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28413882/consequences-of-surface-oxophilicity-of-ni-ni-co-and-co-clusters-on-methane-activation
#10
Weifeng Tu, Mireille Ghoussoub, Chandra Veer Singh, Ya-Huei Cathy Chin
This study describes a new C-H bond activation pathway during CH4-CO2 reactions on oxophilic Ni-Co and Co clusters, unlike those established previously on Ni clusters. The initial C-H bond activation remains as the sole kinetically relevant step on Ni-Co, Ni, and Co clusters, but their specific reaction path varies. On Ni clusters, C-H bond activation occurs via an oxidative addition step that involves a three center (H3C∙∙∙*∙∙∙H)(‡) transition state, during which a Ni atom inserts into the C-H bond and donates its electron density into the C-H bond anti-bonding orbital...
April 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28412156/tyrosine-oxidation-and-nitration-in-transmembrane-peptides-is-connected-to-lipid-peroxidation
#11
Silvina Bartesaghminni, Daniel Herrera, Débora M Martinez, Ariel Petruk, Verónica Demicheli, Madia Trujillo, Marcelo A Martí, Darío A Estrín, Rafael Radi
Tyrosine nitration is an oxidative post-translational modification that can occur in proteins associated to hydrophobic bio-structures such as membranes and lipoproteins. In this work, we have studied tyrosine nitration in membranes using a model system consisting of phosphatidylcholine liposomes with pre-incorporated tyrosine-containing 23 amino acid transmembrane peptides. Tyrosine residues were located at positions 4, 8 or 12 of the amino terminal, resulting in different depths in the bilayer. Tyrosine nitration was accomplished by exposure to peroxynitrite and a peroxyl radical donor or hemin in the presence of nitrite...
April 13, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28411622/modelling-oxide-formation-and-growth-on-platinum
#12
Heather A Baroody, Gregory Jerkiewicz, Michael H Eikerling
We present a mathematical model of oxide formation and growth on platinum. The motivation stems from the necessity to understand platinum dissolution in the cathode catalyst layer of polymer electrolyte fuel cells. As is known, platinum oxide formation and reduction are strongly linked to platinum dissolution processes. However, a consistent model of the oxidation processes on platinum does not exist. Our oxide growth model links interfacial exchange processes between platinum and oxygen ions with the transport of oxygen ion vacancies via diffusion and migration...
April 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28411556/hydrogen-peroxide-modifies-both-activity-and-isoforms-of-acetylcholinesterase-in-human-neuroblastoma-sh-sy5y-cells
#13
Alba Garcimartín, M Elvira López-Oliva, M Pilar González, Francisco J Sánchez-Muniz, Juana Benedí
The involvement of cholinergic system and the reactive oxygen species (ROS) in the pathogenesis of some degenerative diseases has been widely reported; however, the specific impact of hydrogen peroxide (H2O2) on the acetylcholinesterase (AChE) activity as well as AChE isoform levels has not been clearly established. Hence, the purpose of present study is to clarify whether H2O2 alters these parameters. Human neuroblastoma SH-SY5Y cells were treated with H2O2 (1-1000µM) for 24h and AChE activity and AChE and cytochrome c levels were evaluated...
April 4, 2017: Redox Biology
https://www.readbyqxmd.com/read/28409339/quantification-of-tumor-hypoxic-fractions-using-positron-emission-tomography-with-18-f-fluoromisonidazole-18-f-fmiso-kinetic-analysis-and-invasive-oxygen-measurements
#14
Olivia J Kelada, Sara Rockwell, Ming-Qiang Zheng, Yiyun Huang, Yanfeng Liu, Carmen J Booth, Roy H Decker, Uwe Oelfke, Richard E Carson, David J Carlson
PURPOSE: The purpose of this study is to use dynamic [(18)F]fluoromisonidazole ([(18)F]FMISO) positron emission tomography (PET) to compare estimates of tumor hypoxic fractions (HFs) derived by tracer kinetic modeling, tissue-to-blood ratios (TBR), and independent oxygen (pO2) measurements. PROCEDURES: BALB/c mice with EMT6 subcutaneous tumors were selected for PET imaging and invasive pO2 measurements. Data from 120-min dynamic [(18)F]FMISO scans were fit to two-compartment irreversible three rate constant (K 1, k 2, k 3) and Patlak models (K i)...
April 13, 2017: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
https://www.readbyqxmd.com/read/28407542/diclofenac-degradation-in-water-by-feceox-catalyzed-h2o2-influencing-factors-mechanism-and-pathways
#15
Shan Chong, Guangming Zhang, Nan Zhang, Yucan Liu, Ting Huang, Huazhen Chang
The degradation of diclofenac in a like Fenton system, FeCeOx-H2O2, was studied in details. The influencing factors, reaction kinetics, reaction mechanism and degradation pathways of diclofenac were investigated. The optimum conditions were at a solution pH of 5.0, H2O2 concentration of 3.0mmol/L, diclofenac initial concentration of 0.07mmol/L, FeCeOx dosage of 0.5g/L, and 84% degradation of diclofenac was achieved within 40min. The kinetics of FeCeOx catalyzed H2O2 process involved adsorption-dominating and degradation-dominating stages and fitted pseudo-second order model and pseudo-first order model, respectively...
April 5, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28406298/reaction-of-aniline-with-singlet-oxygen-o2-1-%C3%AE-g
#16
Jomana Al-Nu'airat, Mohammednoor K Altarawneh, Xiangpeng Gao, Phillip R Westmoreland, Bogdan Z Dlugogorski
Dissolved organic matter (DOM) acts as an effective photochemical sensitiser that produces the singlet delta state of molecular oxygen (O2 1Δg), a powerful oxidiser that removes aniline from aqueous solutions. However, the exact mode of this reaction, the para to ortho-iminobenzoquinone ratio, and the selectivity of one over the other remain largely speculative. This contribution resolves these uncertainties. We report, for the first time, a comprehensive mechanistic and kinetic account of the oxidation of aniline with the singlet delta oxygen using B3LYP and M06 functionals in both gas and aqueous phases...
April 13, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28406257/nitrogen-doped-carbon-encapsulating-%C3%AE-moc-ni-heterostructures-for-efficient-oxygen-evolution-electrocatalysts
#17
Xueping Zhang, Liang Huang, Yujie Han, Miao Xu, Shaojun Dong
Developing efficient and earth-abundant oxygen evolution reaction (OER) electrocatalysts is of great importance in renewable energy research. Herein, we report nitrogen-doped carbon encapsulating γ-MoC/Ni heterostructures (γ-MoC/Ni@NC) for the first time as efficient OER electrocatalysts. The composites can be controlled by the addition of a Mo source to form a nanoparticle-assembled hierarchically porous nanostructure, which can enlarge the specific surface area, thus exposing more active sites. Moreover, we demonstrate that the formation of γ-MoC@Ni heterostructures and the resulting synergistic effect between γ-MoC and Ni can facilitate the reaction kinetics, leading to significantly improved OER activity with an onset overpotential of merely 240 mV, and a low overpotential of 310 mV to afford a current density of 10 mA cm(-2)...
April 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/28405646/half-sandwich-iridium-n-heterocyclic-carbene-anticancer-complexes
#18
Chuanlan Wang, Jinfeng Liu, Zhenzhen Tian, Meng Tian, Laijin Tian, Wenqian Zhao, Zhe Liu
Half-sandwich pseudo-octahedral pentamethylcyclopentadienyl Ir(III) complexes of the type [(η(5)-Cp(x))Ir(C^C)Cl]PF6, where Cp(x) is pentamethylcyclopentadienyl (Cp*), or its phenyl (Cp(xph) = C5Me4C6H5) or biphenyl (Cp(xbiph) = C5Me4C6H4C6H5) derivatives, and the C^C-chelating ligands are different N-heterocyclic carbene (NHC) ligands, have been synthesized and characterized. Three X-ray crystal structures have been determined. Except for Cp* complex 1A, the other eleven complexes 1B-4C all showed potent cytotoxicity, with IC50 values ranging from 2...
April 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28403611/kot-bu-catalyzed-dehydrogenative-c-h-silylation-of-heteroaromatics-a-combined-experimental-and-computational-mechanistic-study
#19
Wen-Bo Liu, David P Schuman, Yun-Fang Yang, Anton Alexandrovich Toutov, Yong Liang, Hendrik F T Klare, Nasri Nesnas, Martin Oestreich, Donna G Blackmond, Scott C Virgil, Shibdas Banerjee, Richard N Zare, Robert H Grubbs, Kendall N Houk, Brian M Stoltz
We recently reported a new method for the direct dehydrogenative C-H silylation of heteroaromatics utilizing Earth-abundant potassium tert-butoxide. Herein we report a systematic experimental and computational mechanistic investigation of this transformation. Our experimental results are consistent with a radical chain mechanism. A trialkylsilyl radical may be initially generated by homolytic cleavage of a weakened Si-H bond of a hypercoordinated silicon species as detected by IR, or by traces of oxygen which can generate a reactive peroxide by reaction with (KOt-Bu)4 as indicated by density functional theory (DFT) calculations...
April 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28402870/long-chain-fatty-acid-feeding-frequency-in-anaerobic-codigestion-impacts-syntrophic-community-structure-and-biokinetics
#20
Ryan M Ziels, David A C Beck, H David Stensel
This study investigated the impacts of long-chain fatty acid (LCFA) feeding frequencies on microbial community structure, bioconversion kinetics, and process stability during anaerobic codigestion. Parallel laboratory-scale anaerobic codigesters fed with dairy cattle manure were either pulse-fed every two days or continuously-fed daily, respectively, with oleate (C18:1) in incremental step increases over 200 days up to 64% of the influent chemical oxygen demand (COD). The effluent acetate concentration exceeded 3000 mg/L in the continuous-fed codigester at the highest oleate loading rate, but remained below 100 mg/L in the pulse-fed codigester at the end of its 48-hr oleate feed cycle...
March 31, 2017: Water Research
keyword
keyword
6949
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"