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Oxygen kinetics

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https://www.readbyqxmd.com/read/28340419/photolytic-degradation-of-the-%C3%AE-blocker-nebivolol-in-aqueous-solution
#1
Alaa Salma, Holger V Lutze, Torsten C Schmidt, Jochen Tuerk
Nebivolol (NEB) is one of the top-sold prescription drugs belonging to the third generation of beta-blockers. However, so far, occurrence data in the environment are lacking. Within this study NEB has been found for the first time in effluent samples of wastewater treatment plants in Germany with an average concentration of 13 ng L(-1). Its photodegradation behavior in the environment and in technical processes is largely unknown. To fill this gap, three different UV treatment procedures (UV-C at 254 nm, UV-B at 312 nm and UV-A at 365 nm) were investigated in three different matrices: pure water, pure water in presence of the hydroxyl radical (OH) scavenger tert...
March 13, 2017: Water Research
https://www.readbyqxmd.com/read/28339179/synthesis-of-111-facet-exposed-mgo-with-surface-oxygen-vacancies-for-ros-generation-in-the-dark
#2
Ying-Juan Hao, Bing Liu, Li-Gang Tian, Fa-Tang Li, Jie Ren, Shao-Jia Liu, Ying Liu, Jun Zhao, Xiaojing Wang
Seeking a simple and moderate route to generate reactive oxygen species (ROS) for antibiosis is of great interest and challenge. This work demonstrates that molecule transition and electron rearrangement processes can directly occur only through chemisorption interaction between the adsorbed O2 and high-energy {111} facet-exposed MgO with abundant surface oxygen vacancies (SOVs), hence producing singlet oxygen and superoxide anion radicals without light irradiation. These ROS were confirmed by electron paramagnetic resonance, in-situ Raman and scavenger experiments, respectively...
March 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28335257/characteristic-evaluation-of-graphene-oxide-for-bisphenol-a-adsorption-in-aqueous-solution
#3
Thatchaphong Phatthanakittiphong, Gyu Tae Seo
This paper investigates the characteristics of graphene oxide (GO) for Bisphenol A (BPA) adsorption in water. Batch experiments on the influence of significant parameters were performed. While an improvement of the adsorption capacity of BPA was obtained by the increment of contact time and the initial BPA concentration, the increment of pH above 8, GO dosage, and temperature showed the reverse results. The thermodynamic study suggested that BPA adsorption on GO was an exothermic and spontaneous process. The kinetics was explained by the pseudo-second-order model which covers all steps of adsorption...
July 2, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334542/-an-assessment-of-vo2-kinetics-in-the-recovery-phase-of-cardiopulmonary-exercise-test-in-patients-with-heart-disease-importance-and-classification
#4
Leona Mífková, František Várnay, Pavel Homolka, Petr Dobšák
The article reviews the course of VO2 in the phase of recovery kinetics of oxygen uptake (VO2rec) cardiopulmonary exercise test. VO2rec kinetics cannot be completely defined using a single parameter. The article describes the three most frequently used methods: %VO2-REC2, T1/2 VO2rec and TC VO2, and provides detailed procedures of their analysis. The three aforementioned parameters are also at the heart of our classification of VO2rec. The method %VO2-REC2 is an essential one, in our view, since its prognostic significance is proven and it can be also easily applied only based on a data record of the cardiopulmonary exercise test...
2017: Vnitr̆ní Lékar̆ství
https://www.readbyqxmd.com/read/28332113/the-critical-power-concept-applications-to-sports-performance-with-a-focus-on-intermittent-high-intensity-exercise
#5
REVIEW
Andrew M Jones, Anni Vanhatalo
The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship 'levels off' at a 'critical power' (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake ([Formula: see text]), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs...
March 22, 2017: Sports Medicine
https://www.readbyqxmd.com/read/28330350/communication-calculations-of-the-2-%C3%A3-1-o-reconstruction-kinetics-on-cu-110
#6
Xin Lian, Penghao Xiao, Renlong Liu, Graeme Henkelman
Density functional theory calculations are used to study the elementary processes of the formation of the (2 × 1)-O reconstruction on the Cu(110) surface. The (2 × 1)-O reconstruction requires additional Cu atoms to form Cu-O rows on top of the surface. Both terrace and step sites are considered as the source of Cu adatoms. On terraces, adsorbed oxygen induces the ejection of Cu atoms to form -O-Cu-O- units, leaving Cu vacancies behind. The barrier for subsequent unit growth, however, is prohibitively high...
March 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28328295/electrochemical-treatment-of-tannery-wastewater-raw-coagulated-and-pretreated-by-aops
#7
Jeremi H Naumczyk, Małgorzata A Kucharska
This study on tannery wastewater treatment showed that indirect electrooxidation by chlorine generated at a Ti/SnO2/PdO2/RuO2 (SPR) anode led to full ammonia removal, and a decrease in chemical oxygen demand (COD) of up to 77.0%. A combined process of coagulation + H2O2/UV + electrooxidation allowed us to achieve a decrease in COD of up to 97.5%. Equations describing the kinetics of the decrease in COD, the relationship between the decrease in COD and current, and the relationship between the current efficiency of COD reduction and the initial concentrations of the reagents were established...
March 22, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/28326231/in-situ-monitoring-by-raman-spectroscopy-of-the-thermal-doping-of-graphene-and-mos2-in-o2-controlled-atmosphere
#8
Aurora Piazza, Filippo Giannazzo, Gianpiero Buscarino, Gabriele Fisichella, Antonino La Magna, Fabrizio Roccaforte, Marco Cannas, Franco Mario Gelardi, Simonpietro Agnello
The effects of temperature and atmosphere (air and O2) on the doping of monolayers of graphene (Gr) on SiO2 and Si substrates, and on the doping of MoS2 multilayer flakes transferred on the same substrates have been investigated. The investigations were carried out by in situ micro-Raman spectroscopy during thermal treatments up to 430 °C, and by atomic force microscopy (AFM). The spectral positions of the G and 2D Raman bands of Gr undergo only minor changes during treatment, while their amplitude and full width at half maximum (FWHM) vary as a function of the temperature and the used atmosphere...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28325907/photosensitization-of-tio2-nanofibers-by-ag2s-with-the-synergistic-effect-of-excess-surface-ti-3-states-for-enhanced-photocatalytic-activity-under-simulated-sunlight
#9
Samina Ghafoor, Sadia Ata, Nasir Mahmood, Salman Noshear Arshad
TiO2 nanofibers, with mean diameter ~200 nm, were fabricated by electrospinning and successfully photosensitized with low bandgap Ag2S nanoparticles of 11, 17, 23 and 40 nm mean sizes, with corresponding loading of 4, 10, 18 and 29 wt.% Ag2S, respectively. 17 nm Ag2S@TiO2 nanofibers exhibited optimal activity in the photodegradation of methylene blue under simulated sunlight with pseudo-first order rate constant of 0.019 min(-1) compared to 0.009 min(-1) for pure TiO2 nanofibers. In spite of greater visible-light absorption and reduced bandgap, larger than 17 nm Ag2S nanoparticles exhibited sluggish photodegradation kinetics probably due to less photo-induced carriers generation in TiO2 and reduced electron injection rates from the larger sized Ag2S into TiO2...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28324835/flexible-biological-arsenite-oxidation-utilizing-nox-and-o2-as-alternative-electron-acceptors
#10
Jie Wang, Junfeng Wan, Zihao Wu, Hongli Li, Haisong Li, Christophe Dagot, Yan Wang
The feasibility of flexible microbial arsenite (As(III)) oxidation coupled with the reduction of different electron acceptors was investigated. The results indicated the acclimated microorganisms could oxidize As(III) with oxygen, nitrate and nitrite as the alternative electron acceptors. A series of batch tests were conducted to measure the kinetic parameters of As(III) oxidation and to evaluate the effects of environmental conditions including pH and temperature on the activity of biological As(III) oxidation dependent on different electron acceptors...
March 18, 2017: Chemosphere
https://www.readbyqxmd.com/read/28324710/dual-substrate-limitation-modeling-and-implications-for-mainstream-deammonification
#11
Heather A Stewart, Ahmed Al-Omari, Charles Bott, Haydee De Clippeleir, Chunyang Su, Imre Takacs, Bernhard Wett, Arash Massoudieh, Sudhir Murthy
Substrate limitation occurs frequently in wastewater treatment and knowledge about microbial behavior at limiting conditions is essential for the use of biokinetic models in system design and optimization. Monod kinetics are well-accepted for modeling growth rates when a single substrate is limiting, but several models exist for treating two or more limiting substrates simultaneously. In this study three dual limitation models (multiplicative, minimum, and Bertolazzi) were compared based on experiments using nitrite-oxidizing bacteria (limited by dissolved oxygen and nitrite) and ANaerobic AMMonia-OXidizing bacteria or Aanammox (limited by ammonium and nitrite) within mixed liquor from deammonification pilots...
March 9, 2017: Water Research
https://www.readbyqxmd.com/read/28322329/an-expanded-multi-scale-monte-carlo-simulation-method-for-personalized-radiobiological-effect-estimation-in-radiotherapy-a-feasibility-study
#12
Ying Zhang, Yuanming Feng, Wei Wang, Chengwen Yang, Ping Wang
A novel and versatile "bottom-up" approach is developed to estimate the radiobiological effect of clinic radiotherapy. The model consists of multi-scale Monte Carlo simulations from organ to cell levels. At cellular level, accumulated damages are computed using a spectrum-based accumulation algorithm and predefined cellular damage database. The damage repair mechanism is modeled by an expanded reaction-rate two-lesion kinetic model, which were calibrated through replicating a radiobiological experiment. Multi-scale modeling is then performed on a lung cancer patient under conventional fractionated irradiation...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28319867/phototherapeutic-spectrum-expansion-through-synergistic-effect-of-mesoporous-silica-trio-nanohybrids-against-antibiotic-resistant-gram-negative-bacterium
#13
Yaswanth Kuthati, Ranjith Kumar Kankala, Prabhakar Busa, Shi-Xiang Lin, Jin-Pei Deng, Chung-Yuan Mou, Chia-Hung Lee
The extensive impact of antibiotic resistance has led to the exploration of new anti-bacterial modalities. We designed copper impregnated mesoporous silica nanoparticles (Cu-MSN) with immobilizing silver nanoparticles (SNPs) to apply photodynamic inactivation (PDI) of antibiotic-resistant E. coli. SNPs were decorated over the Cu-MSN surfaces by coordination of silver ions on diamine-functionalized Cu-MSN and further reduced to silver nanoparticles with formalin. We demonstrate that silver is capable of sensitizing the gram-negative bacteria E...
March 7, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28319739/mechanism-and-kinetics-of-halogenated-compound-removal-by-metallic-iron-transport-in-solution-diffusion-and-reduction-within-corrosion-films
#14
Shun Tang, Xiao-Mao Wang, Shi-Ting Liu, Hong-Wei Yang, Yuefeng F Xie, Xiao-Yi Yang
A detailed kinetic model comprised of mass transport (ktra), pore diffusion (kdif), adsorption and reduction reaction (krea), was developed to quantitatively evaluate the effect of corrosion films on the removal rate (kobs) of halogenated compounds by metallic iron. Different corrosion conditions were controlled by adjusting the iron aging time (0 or 1 yr) and dissolved oxygen concentration (0-7.09 mg/L DO). The kobs values for bromate, mono-, di- and tri-chloroacetic acids (BrO3(-), MCAA, DCAA and TCAA) were 0...
March 6, 2017: Chemosphere
https://www.readbyqxmd.com/read/28319367/structural-stability-from-crystallographic-shear-in-tio2-nb2o5-phases-cation-ordering-and-lithiation-behavior-of-tinb24o62
#15
Kent J Griffith, Anatoliy Senyshyn, Clare P Grey
The host structure and reversible lithium insertion and extraction of an intercalation compound, TiNb24O62, are described. Neutron diffraction, applied for the first time to TiNb24O62, allowed an accurate refinement of the complex block superstructure, particularly with respect to the oxygen sublattice. Analysis of the transition-metal sites revealed significant cation ordering in the mixed-metal oxide. Electrochemical analysis demonstrated highly reversible lithium intercalation with ca. 190 mA·h·g(-1) after 100 cycles (C/10 rate, 3 months)...
March 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28304021/mechanisms-of-direct-hydrogen-peroxide-synthesis-on-silicon-and-phosphorus-dual-doped-graphene-a-dft-d-study
#16
Shuo Li, Zhansheng Lu, Yi Zhang, Dongwei Ma, Zongxian Yang
Hydrogen peroxide (H2O2) is an important chemical commodity, with demand growing significantly in chemical synthesis due to its green characteristics. The mechanisms of the direct synthesis of hydrogen peroxide (DSHP) on metal-free silicon and phosphorus dual-doped graphene (Si-P-G) catalyst, based on a dispersion-corrected density functional theory (DFT-D) method, are systematically investigated. The most stable Si-P-G catalyst is presented, with the local region of dopants shown to play an important role in the adsorption and reduction of oxygen...
March 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28301444/hemodynamic-and-cardiorespiratory-predictors-of-sport-rock-climbing-performance
#17
Simon Fryer, David Giles, Inmaculada Garrido Palomino, Alejandro de la O Puerta, Vanesa España Romero
Rock climbing performance has been suggested to involve a notable contribution from the aerobic metabolism. Previously it has been shown that forearm oxygenation kinetics can be used to distinguish ability groups and predict red-point sport climbing performance. Currently it is not known if forearm oxygenation kinetics, or a sport specific assessment of cardiorespiratory fitness best predicts sport rock climbing performance. The aim of the study was to determine whether forearm oxidative capacity index, maximal de-oxygenation (Δ score) during a treadwall V[Combining Dot Above]O[SUBSCRIPT TWO]peak test, treadwall V[Combining Dot Above]O[SUBSCRIPT TWO]peak, or running V[Combining Dot Above]O[SUBSCRIPT TWO]max best predicts self-reported sport climbing performance...
March 13, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28301436/the-effects-of-recovery-duration-during-high-intensity-interval-exercise-on-time-spent-at-high-rates-of-oxygen-consumption-oxygen-kinetics-and-blood-lactate
#18
Ilias Smilios, Aristides Myrkos, Andreas Zafeiridis, Argyris Toubekis, Apostolos Spassis, Savas P Tokmakidis
The recovery duration and the work to recovery ratio are important aspects to consider when designing a high-intensity aerobic interval exercise (HIIE). This study examined the effects of recovery duration on total exercise time performed above 80, 90 and 95% of maximum oxygen consumption (VO2max) and heart rate (HRmax) during a single-bout HIIE. We also evaluated the effects on VO2 and HR kinetics, blood lactate concentration and rating of perceived exertion (RPE). Eleven moderately trained males (22.1±1 yrs...
March 13, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28300349/equatorial-ligand-perturbations-influence-the-reactivity-of-manganese-iv-oxo-complexes
#19
Allyssa A Massie, Melissa C Denler, Luísa Thiara Cardoso, Ashlie N Walker, M Kamal Hossain, Victor W Day, Ebbe Nordlander, Timothy A Jackson
Manganese(IV)-oxo complexes are often invoked as intermediates in Mn-catalyzed C-H bond activation reactions. While many synthetic Mn(IV) -oxo species are mild oxidants, other members of this class can attack strong C-H bonds. The basis for these reactivity differences is not well understood. Here we describe a series of Mn(IV) -oxo complexes with N5 pentadentate ligands that modulate the equatorial ligand field of the Mn(IV) center, as assessed by electronic absorption, electron paramagnetic resonance, and Mn K-edge X-ray absorption methods...
March 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28300265/catalytic-routes-to-fuels-from-c1-and-oxygenate-molecules
#20
Shuai Wang, Iker Agirrezabal-Telleria, Aditya Bhan, Dante Simonetti, Kazuhiro Takanabe, Enrique Iglesia
This account illustrates concepts in chemical kinetics underpinned by the formalism of transition state theory using catalytic processes that enable the synthesis of molecules suitable as fuels from C1 and oxygenate reactants. Such feedstocks provide an essential bridge towards a carbon-free energy future, but their volatility and low energy density require the formation of new C-C bonds and the removal of oxygen. These transformations are described here through recent advances in our understanding of the mechanisms and site requirements in catalysis by surfaces, with emphasis on enabling concepts that tackle ubiquitous reactivity and selectivity challenges...
March 16, 2017: Faraday Discussions
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