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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/28819754/development-of-the-hybrid-cells-in-series-model-to-simulate-ammonia-nutrient-pollutant-transport-along-the-umgeni-river
#1
Kayode O Olowe, Muthukrishnavellaisamy Kumarasamy
Discharge of organic waste results in high nutrient pollution of the water bodies which is a major menace to the environment. A high quantity of nutrients such as ammonia causes a reduction in the dissolved oxygen level and induces algal growth in the water bodies. Water quality models have been the tools to evaluate the rate at which streams can disperse the pollutants they receive. Many water quality models are flawed either because of their inadequacy to completely simulate the advection component of the pollutant transport, or because of the limited application of the models, due to inaccurate estimation of model parameters...
August 17, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28810981/thermoregulatory-response-to-exercise-after-exertional-heat-stroke
#2
Emmanuel Sagui, Sophie Beighau, Arnaud Jouvion, Julie Trichereau, Delphine Cornet, René Charles Berthelot, Frédéric Canini, Laurent Grélot
BACKGROUND: After one episode of exertional heat stroke (EHS), risk factors must be identified to determine the potential for subsequent episodes. One of these risk factors, core body temperature (Tco) kinetics during strenuous exercise, may be a surrogate marker suggestive of impaired thermoregulation. This study aimed to determine the kinetics of increases in Tco among military subjects who had a history of EHS. METHODS: Forty subjects (38 males, mean age 28.4 ± 4...
July 2017: Military Medicine
https://www.readbyqxmd.com/read/28750180/association-between-inspiratory-muscle-weakness-and-slowed-oxygen-uptake-kinetics-in-patients-with-chronic-obstructive-pulmonary-disease
#3
Andiara Wolpat, Francisco V Lima, Fabiola M Silva, Micheli Tochetto, Andressa Freitas, Tatiane Grandi, Leonardo Rodrigues, Verônica Paiva, Gerson Cipriano, Adriana M Chiappa, Julio Zago, Gaspar R Chiappa
INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) may have poor inspiratory muscle function, which reduces minute and alveolar ventilation, leading to increased hypoxemia and slow pulmonary oxygen uptake ( O2) kinetics. However, little is known about the effect of inspiratory muscle weakness (IMW) on oxygen uptake kinetics in patients with COPD. Thus, we tested the hypothesis that COPD patients with IMW have slowed O2 kinetics. METHODS: An observational study was conducted including COPD patients with moderate to severe airflow limitation and a history of intolerance to exercise...
July 27, 2017: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/28740182/ultrahigh-adsorption-and-singlet-oxygen-mediated-degradation-for-efficient-synergetic-removal-of-bisphenol-a-by-a-stable-zirconium-porphyrin-metal-organic-framework
#4
Ai-Na Meng, Ling-Xiao Chaihu, Huan-Huan Chen, Zhi-Yuan Gu
Bisphenol A (BPA), one of 23 most important endocrine disrupting chemicals, was efficiently removed and sequentially photodegraded by a zirconium-porphyrin metal-organic framework (MOF) catalyst under visible light for water treatment. Well control of photodegradation allows the kinetic separation of adsorption step and photodegradation step. Ultrahigh adsorption uptake of 487.69 ± 8.37 mg g(-1) is observed, while efficient photodegradation could be observed within 20 min at the rate of 0.004 mg min(-1)...
July 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28734248/effects-of-constructed-wetland-design-on-ibuprofen-removal-a-mesocosm-scale-study
#5
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
#6
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/28721747/faster-v%C3%AC-o2-kinetics-after-priming-exercises-of-different-duration-but-same-fatigue
#7
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/28715773/developmental-toxicity-of-fe3o4-nanoparticles-on-cysts-and-three-larval-stages-of-artemia-salina
#8
Song Zhu, Ming-Yang Xue, Fei Luo, Wei-Chao Chen, Bin Zhu, Gao-Xue Wang
Using Artemia salina cysts (capsulated and decapsulated) and larvae (instar I, II and III) as experimental models, the potential effects of Fe3O4 nanoparticles (Fe3O4-NPs) on marine ecosystems were investigated. Hatchability, mortality and a number of ethological, morphological and biochemical parameters were selected as end-points to define the toxic responses. Data showed that the hatching rates of capsulated and decapsulated cysts were significantly decreased (p < 0.01) following exposure to 600 mg/L for 24 and 36 h...
July 14, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28711566/developmental-toxicity-of-oxidized-multi-walled-carbon-nanotubes-on-artemia-salina-cysts-and-larvae-uptake-accumulation-excretion-and-toxic-responses
#9
Song Zhu, Fei Luo, Xiao Tu, Wei-Chao Chen, Bin Zhu, Gao-Xue Wang
Using Artemia salina (A. salina) cysts (capsulated and decapsulated) and larvae [instar I (0-24 h), II (24-48 h) and III (48-72 h)] as experimental models, developmental toxicity of oxidized multi-walled carbon nanotubes (O-MWCNTs) was evaluated. Results revealed that hatchability of capsulated and decapsulated cysts was significantly decreased (p < 0.01) following exposure to 600 mg/L for 36 h. Mortality rates were 33.8, 55.7 and 40.7% for instar I, II and III larvae in 600 mg/L. The EC50 values for swimming inhibition of instar I, II and III were 535, 385 and 472 mg/L, respectively...
July 13, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28697646/effects-of-perlite-and-caustic-soda-on-microorganism-activities-of-leachate-in-sequence-batch-reactor
#10
Etesam Ganjian, Majid Peyravi, Ali Asqar Qoreyshi, Mohsen Jahanshahi, Soodabeh Khalili, Ali Shokuhi Rad
The purpose of this article is to evaluate the effect of adsorbents and alkali pre-treatment on microorganism activities of activated sludge (AS) for the treatment of landfill leachate (LFL). The COD and BOD5/COD ratio of LFL used in this research were 10500 and 0.68, respectively which they show the efficient biodegradation of LFL by aerobic bacteria. In order to survey the role of porous absorbent, perlite was employed as an alternative with low porosity and was compared to powdered activated carbon (PAC) which has been most widely used in the treatment process...
July 11, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28693357/effect-of-acute-ambient-temperature-exposure-on-cardio-pulmonary-and-respiratory-kinetics-in-men
#11
U Drescher, J Koschate, U Hoffmann, S Schneider, A Werner
PURPOSE: The goal of the study was to compare the kinetics responses of heart rate (HR) and pulmonary (V'O2pulm) and muscular (V'O2musc) oxygen uptake during dynamic leg exercise across different acute ambient temperature conditions in a climatic chamber. METHODS: Thirteen physically healthy, active male volunteers performed pseudo-random binary sequence (PRBS) work rate (WR) changes between 30 W and 80 W at 15°C, 25°C and 35°C, respectively. HR was measured beat-to-beat by echocardiogram and V'O2pulm by breath-by-breath gas exchange, and V'O2musc estimations were assessed by applying a circulatory model and cross-correlation functions based on the approach of Hoffmann et al...
July 10, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28689985/oxygen-consumption-and-carbon-dioxide-recovery-kinetics-in-the-prediction-of-coronary-artery-disease-severity-and-outcome
#12
Dejana Popovic, Dejana Martic, Tea Djordjevic, Vesna Pesic, Marco Guazzi, Jonathan Myers, Reza Mohebi, Ross Arena
BACKGROUND: Revascularization appears to be beneficial only in patients with high levels of ischemia. This study examined the utility of gas analysis during the recovery phase of cardiopulmonary exercise testing (CPET) in predicting coronary artery disease (CAD) severity and prognosis. METHODS: 40 Caucasian patients (21.2% females), mean age 63.5±7.6 with significant coronary artery lesions (≥50%) were studied. Within two months of coronary angiography, CPET on a treadmill (TM) and recumbent ergometer (RE) were performed on two visits 2-4days apart; subjects were subsequently followed 32±10months...
June 28, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28658949/sink-or-swim-ions-and-organics-at-the-ice-air-interface
#13
Arpa Hudait, Michael T Allen, Valeria Molinero
The ice-air interface is an important locus of environmental chemical reactions. The structure and dynamics of the ice surface impact the uptake of trace gases and kinetics of reactions in the atmosphere and snowpack. At tropospheric temperatures, the ice surface is partially premelted. Experiments indicate that ions increase the liquidity of the ice surface but hydrophilic organics do not. However, it is not yet known the extent of the perturbation solutes induce at the ice surface and what is the role of the disordered liquid-like layer in modulating the interaction between solutes and their mobility and aggregation at the ice surface...
July 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28657812/combined-prior-exercise-and-fast-start-improves-vo2-kinetics-and-cycling-performance
#14
Kirsty Brock, Prokopios Antonellis, Matthew I Black, Fred J DiMenna, Anni Vanhatalo, Andrew M Jones, Stephen J Bailey
PURPOSE: To investigate whether oxygen uptake (V̇o2) kinetics and simulated 4-km cycling performance are synergistically improved by prior 'priming' exercise and an all-out starting strategy. METHODS: Nine males completed four target work trials (114 ± 17 kJ) to assess V̇o2 kinetics and cycling performance in a repeated-measures, cross-over experimental design. Trials were initiated with either a 12-s all-out start or a self-selected start and preceded by prior severe-intensity (70%Δ) priming exercise or no priming exercise...
June 28, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/28646756/protein-functionalization-of-zno-nanostructure-exhibits-selective-and-enhanced-toxicity-to-breast-cancer-cells-through-oxidative-stress-based-cell-death-mechanism
#15
Sailendra Mahanta, S Prathap, Deependra Kumar Ban, Subhankar Paul
Zinc oxide nanostructure (ZnONS) was chemically synthesized and functionalized (FZnONSBLA) with a small protein bovine α-lactalbumin (BLA) by chemical cross-linking methods. Both nano-structures were characterized using various techniques such as electron microscopy, dynamic light scattering (DLS), UV-Vis spectroscopy, FT-IR, photo-luminescence and X-ray diffraction. Electron microscopy and DLS analysis revealed their (ZnONS and FZnONSBLA) average size of 200nm and 450nm, respectively. When cytotoxicity of both the nanostructures were assessed in breast cancer cells MCF-7 and MDAMB231 by MTT assay and PI/Annexin V staining (FACS), FZnONSBLA demonstrated higher cell death than ZnONS primarily due to generation of intracellular reactive oxygen species (ROS)...
June 15, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28642302/residual-erythropoiesis-protects-against-myocardial-hemosiderosis-in-transfusion-dependent-thalassemia-by-lowering-labile-plasma-iron-via-transient-generation-of-apotransferrin
#16
Maciej W Garbowski, Patricia Evans, Evangelia Vlachodimitropoulou, Robert Hider, John B Porter
Cardiosiderosis is a leading cause of mortality in transfusion-dependent thalassemias. Plasma non-transferrin-bound iron and its redox-active component, labile plasma iron, are key sources of iron loading in cardiosiderosis. Risk factors were identified in 73 patients with or without cardiosiderosis. Soluble transferrin receptor-1 levels were significantly lower in patients with cardiosiderosis (odds ratio 21). This risk increased when transfusion-iron loading rates exceeded the erythroid transferrin uptake rate (derived from soluble transferrin receptor-1) by >0...
June 22, 2017: Haematologica
https://www.readbyqxmd.com/read/28634686/respiratory-uptake-and-depuration-kinetics-of-perfluorooctanesulfonate-pfos-in-a-marine-sandworm-species
#17
Takeo Sakurai, Jun Kobayashi, Nozomi Ito, Shigeko Serizawa, Hiroaki Shiraishi, Tohru Yabe, Yuichi Ishii, Noriyuki Suzuki
We determined the respiratory uptake and depuration kinetics of perfluorooctanesulfonate (PFOS) in Perinereis wilsoni, a polychaete sandworm used as a model species to investigate the fate of chemical pollutants in coastal environments. The sandworms were kept in gravel-packed containers, and the water levels were varied cyclically to mimic the tides. We used seawater kept at 17.1°C. A 7-day exposure period was followed by a 9-day depuration period. The dissolved PFOS concentration averaged 28 ng/L during the exposure period...
August 2017: Bulletin of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/28627041/prior-exercise-speeds-pulmonary-oxygen-uptake-kinetics-and-increases-critical-power-during-supine-but-not-upright-cycling
#18
Richie P Goulding, Denise M Roche, Simon Marwood
What is the central question of this study? Critical power (CP) represents the highest work rate for which a metabolic steady state is attainable. The physiological determinants of CP are unclear, but research suggests that CP might be related to the time constant of phase II oxygen uptake kinetics (τV̇O2). What is the main finding and its importance? We provide the first evidence that τV̇O2 is mechanistically related to CP. A reduction of τV̇O2 in the supine position was observed alongside a concomitant increase in CP...
June 19, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28624444/distribution-lipid-bilayer-affinity-and-kinetics-of-the-metabolic-effects-of-dinoseb-in-the-liver
#19
Gabriela Bueno Franco Salla, Lívia Bracht, Anacharis Babeto de Sá-Nakanishi, Angela Valderrama Parizotto, Fabrício Bracht, Rosane Marina Peralta, Adelar Bracht
Dinoseb is a highly toxic pesticide of the dinitrophenol group. Its use has been restricted, but it can still be found in soils and waters in addition to being a component of related pesticides that, after ingestion by humans or animals, can originate the compound by enzymatic hydrolysis. As most dinitrophenols, dinoseb uncouples oxidative phosphorylation. In this study, distribution, lipid bilayer affinity and kinetics of the metabolic effects of dinoseb were investigated, using mainly the isolated perfused rat liver, but also isolated mitochondria and molecular dynamics simulations...
August 15, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/28619032/the-role-of-intracellular-trafficking-of-cdse-zns-qds-on-their-consequent-toxicity-profile
#20
Bella B Manshian, Thomas F Martens, Karsten Kantner, Kevin Braeckmans, Stefaan C De Smedt, Jo Demeester, Gareth J S Jenkins, Wolfgang J Parak, Beatriz Pelaz, Shareen H Doak, Uwe Himmelreich, Stefaan J Soenen
BACKGROUND: Nanoparticle interactions with cellular membranes and the kinetics of their transport and localization are important determinants of their functionality and their biological consequences. Understanding these phenomena is fundamental for the translation of such NPs from in vitro to in vivo systems for bioimaging and medical applications. Two CdSe/ZnS quantum dots (QD) with differing surface functionality (NH2 or COOH moieties) were used here for investigating the intracellular uptake and transport kinetics of these QDs...
June 15, 2017: Journal of Nanobiotechnology
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