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"Oxygen kinetics"

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https://www.readbyqxmd.com/read/29117249/multimodel-inference-applied-to-oxygen-recovery-kinetics-after-6-min-walk-tests-in-patients-with-chronic-obstructive-pulmonary-disease
#1
Florent Baty, Christian Ritz, Signe Marie Jensen, Lukas Kern, Michael Tamm, Martin Hugo Brutsche
6-min walk tests (6MWT) are routinely performed in patients with chronic obstructive pulmonary disease (COPD). Oxygen uptake ([Formula: see text]) kinetics during 6MWT can be modeled and derived parameters provide indicators of patients' exercise capacity. Post-exercise [Formula: see text] recovery also provides important parameters of patients' fitness which has not been extensively investigated in COPD. Several nonlinear regression models with different underlying biological assumptions may be suitable for describing recovery kinetics...
2017: PloS One
https://www.readbyqxmd.com/read/29059243/muscle-oxygenation-in-type-1-diabetic-and-non-diabetic-patients-with-and-without-chronic-compartment-syndrome
#2
Patrik Gustafsson, Albert G Crenshaw, David Edmundsson, Göran Toolanen, Sead Crnalic
BACKGROUND: Type 1 diabetic patients and non-diabetic patients were referred for evaluation for chronic exertional compartment syndrome (CECS) based on clinical examination and complaints of activity-related leg pain in the region of the tibialis anterior muscle. Previous studies using near-infrared spectroscopy (NIRS) showed greater deoxygenation during exercise for CECS patients versus healthy controls; however, this comparison has not been done for diabetic CECS patients. METHODS: We used NIRS to test for differences in oxygenation kinetics for Type 1 diabetic patients diagnosed with (CECS-diabetics, n = 9) versus diabetic patients without (CON-diabetics, n = 10) leg anterior chronic exertional compartment syndrome...
2017: PloS One
https://www.readbyqxmd.com/read/29049884/a-highly-efficient-and-robust-cation-ordered-perovskite-oxides-as-a-bi-functional-catalyst-for-rechargeable-zinc-air-batteries
#3
Yunfei Bu, Ohhun Gwon, Gyutae Nam, Haeseong Jang, Seona Kim, Qin Zhong, Jaephil Cho, Guntae Kim
Of the various catalysts that have been developed to date for high performance and low cost, perovskite oxides have attracted the attention due to their inherent catalytic activity as well as structural and structural flexibility. Especially, high amount of Pr substitution of the cation ordered perovskite oxide originated from the state-of-the-art Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) electrode could be a good electrode or catalyst because of its high oxygen kinetics, electrical conductivity, oxygen capacity and structural stability...
October 19, 2017: ACS Nano
https://www.readbyqxmd.com/read/29048161/effects-of-temperature-and-concentration-on-the-rate-of-photobleaching-of-erythrosine-in-water
#4
Joshua K G Karlsson, Owen J Woodford, Roza Al-Aqar, Anthony Harriman
Erythrosine, a popular food dye, undergoes fast O2-sensitive bleaching in water when subjected to visible light illumination. In dilute solution, erythrosine undergoes photobleaching via first-order kinetics, where the rate of bleaching depends critically on the rate of photon absorption and on the concentration of dissolved oxygen. Kinetic studies indicate that this inherent bleaching is augmented by self-catalysis at higher concentrations of erythrosine and on long exposure times. Under the conditions used, bleaching occurs by way of geminate attack of singlet molecular oxygen on the chromophore...
November 1, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29024227/impact-of-atrial-fibrillation-on-rest-and-exercise-haemodynamics-in-heart-failure-with-mid-range-and-preserved-ejection-fraction
#5
David M Kaye, Frank E Silvestry, Finn Gustafsson, John G Cleland, Dirk J van Veldhuisen, Piotr Ponikowski, Jan Komtebedde, Shane Nanayakkara, Dan Burkhoff, Sanjiv J Shah
AIMS: Heart failure with preserved (HFpEF) and mid-range ejection fraction (HFmrEF) are becoming the most prevalent forms of heart failure. Patients with HFpEF/HFmrEF in atrial fibrillation (AF) have poorer survival and quality of life, but the mechanism underpinning this is unknown. We sought to investigate the influence of AF on the haemodynamic profile of HFpEF/HFmrEF patients at rest and during exercise. METHODS AND RESULTS: We invasively measured central haemodynamics at rest and during symptom-limited supine bicycle exercise in HFpEF/HFmrEF patients, 35 in sinus rhythm and 20 in AF with matched left ventricular ejection fraction...
October 11, 2017: European Journal of Heart Failure
https://www.readbyqxmd.com/read/28919166/kinetic-analysis-of-oxygen-dynamics-under-a-variable-work-rate
#6
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
#7
COMPARATIVE STUDY
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 (m⩒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...
October 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
#8
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
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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