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"Oxygen kinetics"

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https://www.readbyqxmd.com/read/28919166/kinetic-analysis-of-oxygen-dynamics-under-a-variable-work-rate
#1
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/28753391/differences-in-forearm-strength-endurance-and-hemodynamic-kinetics-between-male-boulderers-and-lead-rock-climbers
#2
S Fryer, K J Stone, J Sveen, T Dickson, V España-Romero, D Giles, J Baláš, L Stoner, N Draper
This study examined differences in the oxygenation kinetics and strength and endurance characteristics of boulderers and lead sport climbers. Using near infrared spectroscopy, 13-boulderers, 10-lead climbers, and 10-controls completed assessments of oxidative capacity index and muscle oxygen consumption (mV˙O2) in the flexor digitorum profundus (FDP), and extensor digitorum communis (EDC). Additionally, forearm strength (maximal volitional contraction MVC), endurance (force-time integral FTI at 40% MVC), and forearm volume (FAV and ΔFAV) was assessed...
July 28, 2017: European Journal of Sport Science
https://www.readbyqxmd.com/read/28530476/time-trials-versus-time-to-exhaustion-tests-effects-on-critical-power-w-and-oxygen-uptake-kinetics
#3
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/28524207/untangling-surface-oxygen-exchange-effects-in-yba2cu3o6-x-thin-films-by-electrical-conductivity-relaxation
#4
P Cayado, C F Sánchez-Valdés, A Stangl, M Coll, P Roura, A Palau, T Puig, X Obradors
The kinetics of oxygen incorporation (in-diffusion process) and excorporation (out-diffusion process), in YBa2Cu3O6+x (YBCO) epitaxial thin films prepared using the chemical solution deposition (CSD) methodology by the trifluoroacetate route, was investigated by electrical conductivity relaxation measurements. We show that the oxygenation kinetics of YBCO films is limited by the surface exchange process of oxygen molecules prior to bulk diffusion into the films. The analysis of the temperature and oxygen partial pressure influence on the oxygenation kinetics has drawn a consistent picture of the oxygen surface exchange process enabling us to define the most likely rate determining step...
May 31, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28301444/hemodynamic-and-cardiorespiratory-predictors-of-sport-rock-climbing-performance
#5
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
#6
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/28283422/importance-of-compensatory-heart-rate-increase-during-myocardial-ischemia-to-preserve-appropriate-oxygen-kinetics
#7
Sadamitsu Yoshida, Hitoshi Adachi, Makoto Murata, Junichi Tomono, Shigeru Oshima, Masahiko Kurabayashi
BACKGROUND: Myocardial ischemia induces cardiac dysfunction, resulting in insufficient oxygen supply to peripheral tissues and mismatched energy production during exercise. To relieve the insufficient oxygen supply, heart rate (HR) response is augmented; however, beta-adrenergic receptor blockers (BB) restrict HR response. Although BB are essential drugs for angina pectoris, the effect of BB on exercise tolerance in patients with angina has not been studied. The aim of this study was to clarify the importance of HR augmentation to preserve exercise tolerance in patients with angina pectoris...
March 7, 2017: Journal of Cardiology
https://www.readbyqxmd.com/read/28095747/effects-of-roller-massager-on-muscle-recovery-after-exercise-induced-muscle-damage
#8
Nuno Casanova, Joana F Reis, João R Vaz, Rita Machado, Bruno Mendes, Duane C Button, Pedro Pezarat-Correia, Sandro R Freitas
Two experiments (n = 10) were conducted to determine the effects of roller massager (RM) on ankle plantar flexor muscle recovery after exercise-induced muscle damage (EIMD). Experiment 1 examined both functional [i.e., ankle plantar flexion maximal isometric contraction and submaximal (30%) sustained force; ankle dorsiflexion maximal range of motion and resistance to stretch; and medial gastrocnemius pain pressure threshold] and morphological [cross-sectional area, thickness, fascicle length, and fascicle angle] variables, before and immediately, 1, 24, 48, and 72 h after an EIMD stimulus...
January 18, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/27984902/ab-initio-study-of-nitrogen-and-position-specific-oxygen-kinetic-isotope-effects-in-the-no-o3-reaction
#9
Wendell W Walters, Greg Michalski
Ab initio calculations have been carried out to investigate nitrogen (k(15)/k(14)) and position-specific oxygen (k(17)/k(16)O & k(18)/k(16)) kinetic isotope effects (KIEs) for the reaction between NO and O3 using CCSD(T)/6-31G(d) and CCSD(T)/6-311G(d) derived frequencies in the complete Bigeleisen equations. Isotopic enrichment factors are calculated to be -6.7‰, -1.3‰, -44.7‰, -14.1‰, and -0.3‰ at 298 K for the reactions involving the (15)N(16)O, (14)N(18)O, (18)O(16)O(16)O, (16)O(18)O(16)O, and (16)O(16)O(18)O isotopologues relative to the 14N(16)O and 16O3 isotopologues, respectively (CCSD(T)/6-311G(d))...
December 14, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27827796/effect-of-body-position-and-ventilation-on-umbilical-artery-and-venous-blood-flows-during-delayed-umbilical-cord-clamping-in-preterm-lambs
#10
Stuart B Hooper, Kelly J Crossley, Valerie A Zahra, Jeroen van Vonderen, Alison Moxham, Andrew W Gill, Martin Kluckow, Arjan B Te Pas, Euan M Wallace, Graeme R Polglase
OBJECTIVE: While delayed umbilical cord clamping (UCC) is thought to facilitate placental to infant blood transfusion, the physiological factors regulating flow in the umbilical arteries and veins during delayed UCC is unknown. We investigated the effects of gravity, by changing fetal height relative to the placenta, and ventilation on umbilical blood flows and the cardiovascular transition during delayed UCC at birth. METHODS: Catheters and flow probes were implanted into preterm lambs (128 days) prior to delivery to measure pulmonary, carotid, umbilical artery (UaBF) and umbilical venous (UvBF) blood flows...
July 2017: Archives of Disease in Childhood. Fetal and Neonatal Edition
https://www.readbyqxmd.com/read/27790156/locomotor-muscle-fatigue-does-not-alter-oxygen-uptake-kinetics-during-high-intensity-exercise
#11
James G Hopker, Giuseppe Caporaso, Andrea Azzalin, Roger Carpenter, Samuele M Marcora
The [Formula: see text] slow component ([Formula: see text]) that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre-fatigue condition) or rest for 33 min (control condition) according to a random and counterbalanced order...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27598811/oxygen-and-perfusion-kinetics-in-response-to-fractionated-radiation-therapy-in-fadu-head-and-neck-cancer-xenografts-are-related-to-treatment-outcome
#12
Fangyao Hu, Karthik Vishwanath, Joseph K Salama, Alaattin Erkanli, Bercedis Peterson, James R Oleson, Walter T Lee, David M Brizel, Nimmi Ramanujam, Mark W Dewhirst
PURPOSE: To test whether oxygenation kinetics correlate with the likelihood for local tumor control after fractionated radiation therapy. METHODS AND MATERIALS: We used diffuse reflectance spectroscopy to noninvasively measure tumor vascular oxygenation and total hemoglobin concentration associated with radiation therapy of 5 daily fractions (7.5, 9, or 13.5 Gy/d) in FaDu xenografts. Spectroscopy measurements were obtained immediately before each daily radiation fraction and during the week after radiation therapy...
October 1, 2016: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/27594875/submaximal-oxygen-uptake-kinetics-functional-mobility-and-physical-activity-in-older-adults-with-heart-failure-and-reduced-ejection-fraction
#13
Scott L Hummel, John Herald, Craig Alpert, Kimberlee A Gretebeck, Wendy S Champoux, Donald R Dengel, Peter V Vaitkevicius, Neil B Alexander
BACKGROUND: Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. METHODS: Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls...
July 2016: Journal of Geriatric Cardiology: JGC
https://www.readbyqxmd.com/read/27508761/-op-5d-05-impaired-skeletal-muscle-oxygenation-and-endothelial-function-in-women-with-gestational-diabetes-mellitus-assessed-by-near-infrared-spectroscopy
#14
K Dipla, E Kintiraki, I Grigoriadou, G Triantafyllou, A Triantafyllou, I Zografou, I S Vrabas, A Zafeiridis, D G Goulis, S Douma
OBJECTIVE: Patients with Gestational diabetes mellitus (GDM) are at increased risk for gestational hypertension. Although GDM is considered a mild metabolic dysfunction, some studies have associated GDM with alterations of endothelial responsiveness, whereas, other studies suggested that the time of exposure to hyperglycemia might be insufficient to induce micro- and macrovascular dysfunction. Near-infrared spectroscopy (NIRS) allows a non-invasive monitoring of functional changes in oxygenated hemoglobin (O2Hb) and oxygen tissue saturation (TSI) and the assessment of microvascular function within the skeletal muscle...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27214658/real-time-monitoring-of-specific-oxygen-uptake-rates-of-embryonic-stem-cells-in-a-microfluidic-cell-culture-device
#15
Alexandre Super, Nicolas Jaccard, Marco Paulo Cardoso Marques, Rhys Jarred Macown, Lewis Donald Griffin, Farlan Singh Veraitch, Nicolas Szita
Oxygen plays a key role in stem cell biology as a signaling molecule and as an indicator of cell energy metabolism. Quantification of cellular oxygen kinetics, i.e. the determination of specific oxygen uptake rates (sOURs), is routinely used to understand metabolic shifts. However current methods to determine sOUR in adherent cell cultures rely on cell sampling, which impacts on cellular phenotype. We present real-time monitoring of cell growth from phase contrast microscopy images, and of respiration using optical sensors for dissolved oxygen...
September 2016: Biotechnology Journal
https://www.readbyqxmd.com/read/27145534/differences-in-oxygenation-kinetics-between-the-dominant-and-nondominant-flexor-digitorum-profundus-in-rock-climbers
#16
David Giles, Vanesa España Romero, Inmaculada Garrido, Alejandro de la O Puerta, Keeron Stone, Simon Fryer
PURPOSE: To examine differences in oxygenation kinetics in the nondominant and dominant flexor digitorum profundus (FDP) of rock climbers. METHODS: Participants were 28 sport climbers with a range of on-site abilities (6a+ to 8a French Sport). Using near-infrared spectroscopy, oxygenation kinetics of the FDP was assessed by calculating the time to half recovery (t1/2 recovery) of the tissue-saturation index (TSI) after 3-5 min of ischemia. RESULTS: A 2-way mixed-model ANOVA found a nonsignificant interaction (P = ...
January 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/27089311/development-of-singlet-oxygen-luminescence-kinetics-during-the-photodynamic-inactivation-of-green-algae
#17
Tobias Bornhütter, Judith Pohl, Christian Fischer, Irena Saltsman, Atif Mahammed, Zeev Gross, Beate Röder
Recent studies show the feasibility of photodynamic inactivation of green algae as a vital step towards an effective photodynamic suppression of biofilms by using functionalized surfaces. The investigation of the intrinsic mechanisms of photodynamic inactivation in green algae represents the next step in order to determine optimization parameters. The observation of singlet oxygen luminescence kinetics proved to be a very effective approach towards understanding mechanisms on a cellular level. In this study, the first two-dimensional measurement of singlet oxygen kinetics in phototrophic microorganisms on surfaces during photodynamic inactivation is presented...
April 13, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/26987416/prospects-of-in-vivo-singlet-oxygen-luminescence-monitoring-kinetics-at-different-locations-on-living-mice
#18
Michael Pfitzner, Jan C Schlothauer, Estelle Bastien, Steffen Hackbarth, Lina Bezdetnaya, Henri-Pierre Lassalle, Beate Röder
BACKGROUND: Singlet oxygen observation is considered a valuable tool to assess and optimize PDT treatment. In complex systems, such as tumors in vivo, only the direct, time-resolved singlet oxygen luminescence detection can give reliable information about generation and interaction of singlet oxygen. Up to now, evaluation of kinetics was not possible due to insufficient signal-to-noise ratio. Here we present high signal-to-noise ratio singlet oxygen luminescence kinetics obtained in mouse tumor model under PDT relevant conditions...
June 2016: Photodiagnosis and Photodynamic Therapy
https://www.readbyqxmd.com/read/26510884/renal-hemodynamics-in-aki-in-search-of-new-treatment-targets
#19
Martin Matejovic, Can Ince, Lakhmir S Chawla, Roland Blantz, Bruce A Molitoris, Mitchell H Rosner, Mark D Okusa, John A Kellum, Claudio Ronco
Novel therapeutic interventions are required to prevent or treat AKI. To expedite progress in this regard, a consensus conference held by the Acute Dialysis Quality Initiative was convened in April of 2014 to develop recommendations for research priorities and future directions. Here, we highlight the concepts related to renal hemodynamics in AKI that are likely to reveal new treatment targets on investigation. Overall, we must better understand the interactions between systemic, total renal, and glomerular hemodynamics, including the role of tubuloglomerular feedback...
January 2016: Journal of the American Society of Nephrology: JASN
https://www.readbyqxmd.com/read/26373659/temperature-responses-of-c4-photosynthesis-biochemical-analysis-of-rubisco-phosphoenolpyruvate-carboxylase-and-carbonic-anhydrase-in-setaria-viridis
#20
Ryan A Boyd, Anthony Gandin, Asaph B Cousins
The photosynthetic assimilation of CO2 in C4 plants is potentially limited by the enzymatic rates of Rubisco, phosphoenolpyruvate carboxylase (PEPc), and carbonic anhydrase (CA). Therefore, the activity and kinetic properties of these enzymes are needed to accurately parameterize C4 biochemical models of leaf CO2 exchange in response to changes in CO2 availability and temperature. There are currently no published temperature responses of both Rubisco carboxylation and oxygenation kinetics from a C4 plant, nor are there known measurements of the temperature dependency of the PEPc Michaelis-Menten constant for its substrate HCO3 (-), and there is little information on the temperature response of plant CA activity...
November 2015: Plant Physiology
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