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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/28634686/respiratory-uptake-and-depuration-kinetics-of-perfluorooctanesulfonate-pfos-in-a-marine-sandworm-species
#1
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
#2
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
#3
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 14, 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
#4
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
#5
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-ox-ides-sr2conb1-xtixo6-%C3%AE-0%C3%A2-x%C3%A2-1-as-cathode-materials-for-solid-oxide-fuel-cells
#6
M Teresa Azcondo, Mercedes Yuste, Juan Carlos Perez Flores, Daniel Muñoz Gil, Susana García Martín, Alvaro Muñoz Noval, Inés Puente Orench, Flaviano García Alvarado, Ulises Amador
The perovskite series Sr2CoNb1-xTixO6-δ (0≤x≤1) is investigated in the full compositional range to assess its potential as cathode material for solid state 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 titanium content from x=0 to x=1 produces both oxidation of Co3+ to Co4+ (from 0% up to 40%) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit) though 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
#7
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
#8
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
#9
Thomas Beltrame, Rodrigo Villar, Richard L Hughson
Previous studies in children and older adults demonstrated faster oxygen uptake (VO2) kinetics in males compared to females, but young health 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 VO2, deoxyhemoglobin (HHb), tissue saturation index (TSI), cardiac output (Q) 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
#10
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
https://www.readbyqxmd.com/read/28538301/proposal-of-a-new-specific-cardiopulmonary-exercise-test-for-taekwondo-athletes
#11
Marcus P Araujo, Antônio C L Nóbrega, Gabriel Espinosa, Matheus R Hausen, Renata R T Castro, Pedro P Soares, Jonas L Gurgel
The objective of this study is to evaluate the cardiorespiratory variables of Taekwondo athletes while performing incremental exercise test on an ergometer using a ramp protocol and to propose a specific protocol for assessing these physiological variables during Taekwondo practice. Fourteen athletes participated in 2 incremental exercise tests: a treadmill exercise test (TREADtest) and a Taekwondo-specific exercise test (TKDtest). The TKDtest consists in 1-minute stages of kicks with an incremental load between then...
June 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28537017/copper-bioaccumulation-photosystem-ii-functioning-and-oxidative-stress-in-the-seagrass-cymodocea-nodosa-exposed-to-copper-oxide-nanoparticles
#12
Michael Moustakas, Paraskevi Malea, Katerina Haritonidou, Ilektra Sperdouli
Photosynthetic activity, oxidative stress, and Cu bioaccumulation in the seagrass Cymodocea nodosa were assessed 4, 12, 24, 48, and 72 h after exposure to two copper oxide nanoparticle (CuO NP) concentrations (5 and 10 mg L(-1)). CuO NPs were characterized by scanning electron microscopy (SEM) and dynamic light scattering measurements (DLS). Chlorophyll fluorescence analysis was applied to detect photosystem II (PSII) functionality, while the Cu accumulation kinetics into the leaf blades was fitted to the Michaelis-Menten equation...
May 23, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28530505/ingestion-of-sodium-bicarbonate-nahco3-following-a-fatiguing-bout-of-exercise-accelerates-post-exercise-acid-base-balance-recovery-and-improves-subsequent-high-intensity-cycling-time-to-exhaustion
#13
Lewis A Gough, Steven Rimmer, Callum J Osler, Matthew F Higgins
This study evaluated the ingestion of sodium bicarbonate (NaHCO3) on post-exercise acid-base balance recovery kinetics and subsequent high-intensity cycling time to exhaustion. In a counterbalanced, crossover design, nine healthy and active males (age: 23±2 years, height: 179±5 cm, body mass: 74±9 kg, peak mean minute power (WPEAK) 256±45 W, peak oxygen uptake (V̇O2PEAK) 46±8 ml.kg(-1).min(-1)) performed a graded incremental exercise test, two familiarisation and two experimental trials. Experimental trials consisted of cycling to volitional exhaustion (TLIM1) at 100% WPEAK on two occasions (TLIM1 and TLIM2) interspersed by a 90 min passive recovery period...
May 22, 2017: International Journal of Sport Nutrition and Exercise Metabolism
https://www.readbyqxmd.com/read/28530476/time-trials-versus-time-to-exhaustion-tests-effects-on-critical-power-w-and-oxygen-uptake-kinetics
#14
Bettina Karsten, Jonathan Baker, Fernando Naclerio, Andreas Klose, Antonino Bianco, Alfred Nimmerichter
PURPOSE: To investigate single-day time-to-exhaustion (TTE) and time trial (TT) based laboratory tests values of critical power (CP), Wprime (W') and respective oxygen kinetics responses. METHODS: Twelve cyclists performed a maximal ramp test followed by three TTE and three TT efforts interspersed by a 60-min recovery between efforts. Oxygen uptake was measured during all trials. The mean response time (MRT) was calculated as a description of the overall V̇O2 kinetic response from the onset to 2 min of exercise...
May 22, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/28493692/uptake-kinetics-and-subcellular-compartmentalization-explain-lethal-but-not-sublethal-effects-of-cadmium-in-two-closely-related-amphipod-species
#15
Lena Jakob, Daria S Bedulina, Denis V Axenov-Gribanov, Michael Ginzburg, Zhanna M Shatilina, Yulia A Lubyaga, Ekaterina V Madyarova, Anton N Gurkov, Maxim A Timofeyev, Hans-O Pörtner, Franz J Sartoris, Rolf Altenburger, Till Luckenbach
Eulimnogammarus cyaneus and Eulimnogammarus verrucosus, closely related amphipod species endemic to Lake Baikal, differ with respect to body size (10- to 50-fold lower fresh weights of E. cyaneus) and cellular stress response (CSR) capacity, potentially causing species-related differences in uptake, internal sequestration, and toxic sensitivity to waterborne cadmium (Cd). We found that, compared to E. verrucosus, Cd uptake rates, related to a given exposure concentration, were higher, and lethal concentrations (50%; LC50) were 2...
June 1, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28476919/v%C3%AC-o2-kinetics-associated-with-moderate-intensity-exercise-in-heart-failure-impact-of-intrathecal-fentanyl-inhibition-of-group-iii-iv-locomotor-muscle-afferents
#16
Erik H Van Iterson, Bruce D Johnson, Michael J Joyner, Timothy B Curry, Thomas P Olson
Heart failure (HF) patients demonstrate impaired pulmonary, circulatory, and nervous system responses to exercise. While HF demonstrate prolonged (time-constant, τ) pulmonary oxygen uptake (V̇O2) on-kinetics contributing to exercise intolerance, it is unknown if abnormal V̇O2 kinetics couple with ventilatory and circulatory dysfunction secondary to impaired group III/IV afferents in HF. Because lower-lumbar intrathecal fentanyl inhibits locomotor muscle afferents resulting in improved exercise ventilation and hemodynamics, we tested the hypotheses, HF will demonstrate: 1) rapid V̇O2 on-kinetics, and 2) attenuated steady-state V̇O2 amplitude and oxygen deficit (O2def) during exercise with fentanyl versus placebo...
May 5, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28458202/toxicity-of-%C3%AE-fe2o3-nanoparticles-to-artemia-salina-cysts-and-three-stages-of-larvae
#17
Chunjie Wang, Huali Jia, Lili Zhu, Hui Zhang, Yunsheng Wang
Artemia salina cysts (capsulated and decapsulated) and larvae (instar I, II and III) were exposed to α-Fe2O3 nanoparticles (α-Fe2O3-NPs) to evaluate the effects on marine ecosystems. Hatchability, mortality and a number of ethological, morphological and biochemical parameters were selected as end-points to define the toxic responses. Results indicate that the hatchability of capsulated and decapsulated cysts was significantly decreased (p<0.01) following exposure to 600mg/L at 12, 18, 24 and 36h. Both increases of mortality and decreases of swimming speed were shown concentration-dependent manners...
November 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28450551/data-collection-handling-and-fitting-strategies-to-optimize-accuracy-and-precision-of-oxygen-uptake-kinetics-estimation-from-breath-by-breath-measurements
#18
Alan P Benson, T Scott Bowen, Carrie Ferguson, Scott R Murgatroyd, Harry B Rossiter
Phase 2 pulmonary oxygen uptake kinetics (ϕ2 τVO2P) reflect muscle oxygen consumption dynamics and are sensitive to changes in state of training or health. This study identified an unbiased method for data collection, handling and fitting to optimize VO2P kinetics estimation. A validated computational model of VO2P kinetics and a Monte Carlo approach simulated 2 x 10(5) moderate intensity transitions using a distribution of metabolic and circulatory parameters spanning normal health. Effects of averaging (interpolation, binning, stacking or separate fitting of up to 10 transitions) and fitting procedures (bi-exponential fitting, or ϕ2 isolation by time removal, statistical or derivative methods followed by mono-exponential fitting) on accuracy and precision of ϕ2 τVO2P estimation were assessed...
April 27, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28444930/does-postexercise-modelled-capillary-blood-flow-accurately-reflect-cardiovascular-effects-by-different-exercise-intensities
#19
F Stöcker, C Von Oldershausen, F K Paternoster, T Schulz, R Oberhoffer
Blood flow (BF) in exercising muscles is an important factor for exercise capacity. Recently, a non-invasive method to estimate capillary BF (Qcap ) was introduced. Using this method, the Fick principle is re-arranged by using relative differences in deoxygenated haemoglobin (ΔHHb) as a surrogate for arteriovenous O2 difference and pulmonary oxygen uptake (VO2 ) instead of muscular oxygen uptake. The aim of this study was to examine (I) the relationship between Qcap and exercise intensity during and following exercise, and (II) to critically reflect the Qcap approach...
April 26, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28402178/top-10-research-questions-related-to-youth-aerobic-fitness
#20
Neil Armstrong
Peak oxygen uptake ([Formula: see text]2) is internationally recognized as the criterion measure of youth aerobic fitness, but despite pediatric data being available for almost 80 years, its measurement and interpretation in relation to growth, maturation, and health remain controversial. The trainability of youth aerobic fitness continues to be hotly debated, and causal mechanisms of training-induced changes and their modulation by chronological age, biological maturation, and sex are still to be resolved...
June 2017: Research Quarterly for Exercise and Sport
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