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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/28721747/faster-v%C3%AC-o2-kinetics-after-priming-exercises-of-different-duration-but-same-fatigue
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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...
June 20, 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
#12
Richie P Goulding, Denise M Roche, Simon Marwood
Critical power (CP) is a fundamental parameter defining high-intensity exercise tolerance and is related to the time constant of phase II pulmonary oxygen uptake kinetics (τV̇O2 ). To test the hypothesis that this relationship is causal we determined the impact of prior exercise ("priming") on CP and τV̇O2 in the upright and supine positions. 17 healthy men were assigned to either upright or supine exercise groups, whereby CP, τV̇O2 and muscle deoxyhaemoglobin kinetics (τ[HHb] ) were determined via constant-power tests to exhaustion at four work-rates with (primed) and without (control) priming exercise at ∼31%Δ...
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
#13
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...
June 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
#14
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
https://www.readbyqxmd.com/read/28596271/extracting-aerobic-system-dynamics-during-unsupervised-activities-of-daily-living-using-wearable-sensor-machine-learning-models
#15
Thomas Beltrame, Robert Amelard, Alexander Wong, Richard L Hughson
Physical activity levels are related through algorithms to the energetic demand with no information regarding the integrity of the multiple physiological systems involved in the energetic supply. Longitudinal analysis of the oxygen uptake (VO2) by wearable sensors in realistic settings might permit development of a practical tool for the study of the longitudinal aerobic system dynamics (i.e., VO2 kinetics). This study evaluated aerobic system dynamics based on predicted VO2 data obtained from wearable sensors during unsupervised activities of daily living (uADL)...
June 8, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28594114/defect-chemistry-electrical-properties-and-evaluation-of-new-oxides-sr2-conb1-x-tix-o6-%C3%AE-0%C3%A2-x%C3%A2-1-as-cathode-materials-for-solid-oxide-fuel-cells
#16
María Teresa Azcondo, Mercedes Yuste, Juan Carlos Pérez-Flores, Daniel Muñoz-Gil, Susana García-Martín, Alvaro Muñoz-Noval, Inés Puente Orench, Flaviano García-Alvarado, Ulises Amador
The perovskite series Sr2 CoNb1-x Tix O6-δ (0≤x≤1) was investigated in the full compositional range to assess its potential as cathode material for solid oxide fuel cell (SOFC). The variation of transport properties and thus, the area specific resistances (ASR) are explained by a detailed investigation of the defect chemistry. Increasing the titanium content from x=0-1 produces both oxidation of Co(3+) to Co(4+) (from 0 up to 40 %) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit), although each charge compensation mechanism predominates in different compositional ranges...
June 8, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28590161/nitrogen-and-phosphorus-treatment-of-marine-wastewater-by-a-laboratory-scale-sequencing-batch-reactor-with-eco-friendly-marine-high-efficiency-sediment
#17
Seonghyeon Cho, Jinsoo Kim, Sungchul Kim, Sang-Seob Lee
We screened and identified a NH3-N-removing bacterial strain, Bacillus sp. KGN1 and a PO4(3-)-P removing strain, Vibrio sp. KGP1, from 960 indigenous marine isolates from seawater and marine sediment from Tongyeong, South Korea. We developed eco-friendly high-efficiency marine sludge (eco-HEMS), and inoculated these marine bacterial strains into the marine sediment. A laboratory-scale sequencing batch reactor (SBR) system using the eco-HEMS for marine wastewater from land-based fish farms improved the treatment performance as indicated by 88...
June 7, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28589528/functional-evaluation-in-obese-patients-before-and-after-sleeve-gastrectomy
#18
Daniel Neunhaeuserer, Andrea Gasperetti, Francesco Savalla, Stefano Gobbo, Valentina Bullo, Marco Bergamin, Mirto Foletto, Roberto Vettor, Marco Zaccaria, Andrea Ermolao
BACKGROUND: Although sleeve gastrectomy (SG) has become an important treatment option in severe obesity, cardiorespiratory and muscle function after SG has not adequately been investigated. METHODS: This is an observational study in 26 obese patients (BMI 45.2 ± 5.8 kg/m(2)), comparing physical function before and after 6 months from SG. All available patients listed for SG were here included. Incremental cardiopulmonary exercise tests, standardized strength tests, and balance analysis were performed...
June 6, 2017: Obesity Surgery
https://www.readbyqxmd.com/read/28570840/sex-differences-in-the-oxygen-delivery-extraction-and-uptake-during-moderate-walking-exercise-transition
#19
Thomas Beltrame, Rodrigo Villar, Richard L Hughson
Previous studies in children and older adults demonstrated faster oxygen uptake (V̇O2) kinetics in males compared with females, but young healthy adults have not been studied. We hypothesized that young men would have faster aerobic system dynamics in response to the onset of exercise than women. Interactions between oxygen supply and utilization were characterized by the dynamics of V̇O2, deoxyhemoglobin (HHb), tissue saturation index (TSI), cardiac output (Q̇), and calculated arteriovenous O2 difference (a-vO2diff) in women and men...
June 1, 2017: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/28561192/heart-rate-and-oxygen-uptake-kinetics-in-type-2-diabetes-patients-a-pilot-study-on-the-influence-of-cardiovascular-medication-on-regulatory-processes
#20
Jessica Koschate, Uwe Drescher, Klaus Baum, Christian Brinkmann, Thorsten Schiffer, Joachim Latsch, Klara Brixius, Uwe Hoffmann
The aim of this pilot study was to investigate whether there are differences in heart rate and oxygen uptake kinetics in type 2 diabetes patients, considering their cardiovascular medication. It was hypothesized that cardiovascular medication would affect heart rate and oxygen uptake kinetics and that this could be detected using a standardized exercise test. 18 subjects were tested for maximal oxygen uptake. Kinetics were measured in a single test session with standardized, randomized moderate-intensity work rate changes...
May 2017: Experimental and Clinical Endocrinology & Diabetes
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