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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/29024783/oxygen-uptake-kinetics-following-six-weeks-of-interval-and-continuous-endurance-exercise-training-an-explorative-pilot-study
#1
U Drescher, T Schefter, J Koschate, T Schiffer, K Brixius, S Schneider, U Hoffmann
PURPOSE: The aim of the study was to compare the responses of pulmonary (V'O2pulm) and muscle (V'O2musc) oxygen uptake kinetics before (PRE) and after (POST) six weeks of endurance exercise training. METHODS: Nine untrained individuals performed pseudo-random binary sequences work rate changes between 30W and 80W at PRE and POST training intervention. Heart rate (HR) and V'O2pulm were measured beat-to-beat and breath-by-breath, respectively. V'O2musc was estimated applying the approach of Hoffmann et al...
October 9, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/29018361/new-methods-for-processing-and-quantifying-vo2-kinetics-to-steady-state-vo2-onset-kinetics
#2
Craig R McNulty, Robert A Robergs
Current methods of oxygen uptake (VO2) kinetics data handling may be too simplistic for the complex physiology involved in the underlying physiological processes. Therefore, the aim of this study was to quantify the VO2 kinetics to steady state across the full range of sub-ventilatory threshold work rates, with a particular focus on the VO2 onset kinetics. Ten healthy, moderately trained males participated in five bouts of cycling. Each bout involved 10 min at a percentage of the subject's ventilation threshold (30, 45, 60, 75, 90%) from unloaded cycling...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28990789/singlet-oxygen-production-and-biological-activity-of-hexanuclear-chalcocyanide-rhenium-cluster-complexes-re6q8-cn-6-4-q-s-se-te
#3
Anastasiya O Solovieva, Kaplan Kirakci, Anton A Ivanov, Pavel Kubát, Tatiana N Pozmogova, Svetlana M Miroshnichenko, Elena V Vorontsova, Anton V Chechushkov, Kristina E Trifonova, Maria S Fufaeva, Evgeniy I Kretov, Yuri V Mironov, Alexander F Poveshchenko, Kamil Lang, Michael A Shestopalov
Octahedral rhenium cluster complexes have recently emerged as relevant building blocks for the design of singlet oxygen photosensitizing materials toward biological applications such as blue-light photodynamic therapy. However, their singlet oxygen generation ability as well as biological properties have been studied only superficially. Herein we investigate in detail the singlet oxygen photogeneration, dark and photoinduced cytotoxicity, cellular uptake kinetics, cellular localization and in vitro photoinduced oxidative stress, and photodynamic cytotoxicity of the series of octahedral rhenium cluster complexes [{Re6Q8}(CN)6](4-), where Q = S, Se, Te...
October 9, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28961494/modeling-of-biotic-and-abiotic-processes-affecting-phosphate-oxygen-isotope-ratios-in-a-mineral-water-biota-system
#4
Deb P Jaisi, Yue Hou, Lisa M Stout, Arash Massoudieh
Abiotic and biotic reactions operate side by side in the cycling of phosphorus (P) in the environment, but the relative roles of these two reactions vary both spatially and temporally. In biotic reactions, the uptake and release of P are catalyzed by enzymes and thus change phosphate oxygen isotope ratios, while in abiotic reactions, the absence of hydrolysis-condensation reactions results in no apparent changes in isotope composition, except short-term kinetic isotope effect due solely to preferential ion exchange...
September 17, 2017: Water Research
https://www.readbyqxmd.com/read/28940557/skeletal-muscle-protein-accretion-rates-and-hindlimb-growth-are-reduced-in-late-gestation-intrauterine-growth-restricted-fetal-sheep
#5
Paul J Rozance, Laura Zastoupil, Stephanie R Wesolowski, David A Goldstrohm, Brittany Strahan, Melanie Cree-Green, Melinda Sheffield-Moore, Giacomo Meschia, William W Hay, Randall B Wilkening, Laura D Brown
Reduced skeletal muscle mass in the IUGR fetus persists into adulthood and may contribute to increased metabolic disease risk. To determine how placental insufficiency with reduced oxygen and nutrient supply to the fetus affects hindlimb blood flow, substrate uptake, and protein accretion rates in skeletal muscle, late gestation CON (n = 8) and IUGR (n = 13) fetal sheep were catheterized with aortic and femoral catheters and a flow transducer around the external iliac artery. Muscle protein kinetic rates were measured using isotopic tracers...
September 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28925377/applied-upper-airway-resistance-instantly-affects-breath-components-a-unique-insight-into-pulmonary-medicine
#6
Pritam Sukul, Jochen Schubert, Svend Kamysek, Phillip Trefz, Wolfram Miekisch
Respiratory parameters such as flow or rate have complex effects onto exhalation of volatile substances and can hamper clinical interpretation of breath biomarkers. We investigated effects of progressively applied upper-airway resistances onto exhalation of volatile organic compounds (VOCs) in healthy humans. We performed real-time mass-spectrometric determination of breath volatiles in 50 subjects with parallel non-invasive hemodynamic monitoring, breath-resolved spirometry and capnometry during controlled tidal breathing (12 breaths/min)...
September 19, 2017: Journal of Breath Research
https://www.readbyqxmd.com/read/28919863/oxygen-uptake-kinetics-is-slower-in-swimming-than-arm-cranking-and-cycling-during-heavy-intensity
#7
Ana Sousa, Fabio Borrani, Ferran A Rodríguez, Grégoire P Millet
Oxygen uptake ([Formula: see text]) kinetics has been reported to be influenced by the activity mode. However, only few studies have compared [Formula: see text]O2 kinetics between activities in the same subjects in which they were equally trained. Therefore, this study compared the [Formula: see text]O2 kinetics response to swimming, arm cranking, and cycling within the same group of subjects within the heavy exercise intensity domain. Ten trained male triathletes (age 23.2 ± 4.5 years; height 180.8 ± 8...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28919166/kinetic-analysis-of-oxygen-dynamics-under-a-variable-work-rate
#8
Alexander Artiga Gonzalez, Raphael Bertschinger, Fabian Brosda, Thorsten Dahmen, Patrick Thumm, Dietmar Saupe
Measurements of oxygen uptake are central to methods for the assessment of physical fitness and endurance capabilities in athletes. Two important parameters extracted from such data of incremental exercise tests are the maximal oxygen uptake and the critical power. A commonly accepted model of the dynamics of oxygen uptake during exercise at a constant work rate comprises a constant baseline oxygen uptake, an exponential fast component, and another exponential slow component for heavy and severe work rates...
September 14, 2017: Human Movement Science
https://www.readbyqxmd.com/read/28901530/metabolic-orchestration-of-t-lineage-differentiation-and-function
#9
REVIEW
Carmen S Yong, Daouda Abba Moussa, Gaspard Cretenet, Sandrina Kinet, Valérie Dardalhon, Naomi Taylor
T cells are stimulated by the engagement of antigen, cytokine, pathogen, and hormone receptors. While research performed over many years has focused on deciphering the molecular components of these pathways, recent data underscore the importance of the metabolic environment in conditioning responses to receptor engagement. The ability of T cells to undergo a massive proliferation and cytokine secretion in response to receptor signals requires alterations to their bioenergetic homeostasis, allowing them to meet new energetic and biosynthetic demands...
October 2017: FEBS Letters
https://www.readbyqxmd.com/read/28838760/in-vitro-assessment-of-anti-tumorigenic-mechanisms-and-efficacy-of-nanoala-a-nanoformulation-of-aminolevulic-acid-designed-for-photodynamic-therapy-of-cancer
#10
Laise Rodrigues de Andrade, Fernando Lucas Primo, Jaqueline Rodrigues da Silva, Antonio Claudio Tedesco, Zulmira Guerrero Marques Lacava
BACKGROUND: The development of nanocarriers is an important approach to increase the bioavailability of hydrophilic drugs in target cells. In this work, we evaluated the anti-tumorigenic mechanisms and efficacy of NanoALA, a novel nanoformulation of aminolevulic acid (ALA) based on poly(lactide-co-glycolide) (PLGA) nanocapsules designed for anticancer photodynamic therapy (PDT). METHODS: For this purpose, physicochemical characterization, prodrug incorporation kinetics, biocompatibility and photocytotoxicity tests, analysis of the cell death type and mitochondrial function, measurement of the intracellular reactive oxygen species production and DNA fragmentation were performed in murine mammary carcinoma (4T1) cells...
August 21, 2017: Photodiagnosis and Photodynamic Therapy
https://www.readbyqxmd.com/read/28819754/development-of-the-hybrid-cells-in-series-model-to-simulate-ammonia-nutrient-pollutant-transport-along-the-umgeni-river
#11
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
#12
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
#13
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
#14
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
#15
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...
December 31, 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
#16
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
#17
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
#18
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...
November 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
#19
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...
October 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28697646/effects-of-perlite-and-caustic-soda-on-microorganism-activities-of-leachate-in-sequence-batch-reactor
#20
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
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