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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/28088096/mycelium-transformation-of-streptomyces-toxytricini-into-pellet-role-of-culture-conditions-and-kinetics
#1
Punit Kumar, Kashyap Kumar Dubey
The present study envisages the role of different carbon sources, nitrogen sources, metals, pH, inoculum volume and agitation rate in pellet formation of S. toxytricini at shake-flask level. It was found that galactose, ammonium sulphate, sodium nitrate, Cu(2+), Zn(2+), higher inoculum volume (5% v/v) and agitation rate at 300rpm caused significant reduction in pellet size (up to the range of 30μm-0.5mm) but biomass formations was also reduced subsequently. Interestingly diffused type of morphology was obtained in Fe(2+) supplemented medium with reduced biomass (1...
January 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28057820/blood-flow-regulation-and-oxygen-uptake-during-high-intensity-forearm-exercise
#2
Stian Kwak Nyberg, Ole Kristian Berg, Jan Helgerud, Eivind Wang
The vascular strain is very high during heavy handgrip exercise, but the intensity and kinetics to reach peak blood flow, and peak oxygen uptake, are uncertain. We included 9 young (25±2yr) healthy males to evaluate blood flow and oxygen uptake responses during continuous dynamic handgrip exercise with increasing intensity. Blood flow was measured using Doppler-ultrasound and venous blood was drawn from a deep forearm vein to determine arteriovenous oxygen difference (a-vO2diff) during 6-minutes bouts of 60, 80 and 100% of maximal work rate (WRmax), respectively...
January 5, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28018674/early-phase-recovery-of-cardiorespiratory-measurements-after-maximal-cardiopulmonary-exercise-testing-in-patients-with-chronic-obstructive-pulmonary-disease
#3
Marie Bellefleur, David Debeaumont, Alain Boutry, Marie Netchitailo, Antoine Cuvelier, Jean-François Muir, Catherine Tardif, Jérémy Coquart
Background. This study investigated respiratory gas exchanges and heart rate (HR) kinetics during early-phase recovery after a maximal cardiopulmonary exercise test (CPET) in patients with chronic obstructive pulmonary disease (COPD) grouped according to airflow limitation. Methods. Thirty control individuals (control group: CG) and 81 COPD patients (45 with "mild" or "moderate" airflow limitation, COPDI-II, versus 36 with "severe" or "very severe" COPD, COPDIII-IV) performed a maximal CPET. The first 3 min of recovery kinetics was investigated for oxygen uptake ([Formula: see text]O2), minute ventilation ([Formula: see text]), respiratory equivalence, and HR...
2016: Pulmonary Medicine
https://www.readbyqxmd.com/read/27994556/endurance-performance-during-severe-intensity-intermittent-cycling-effect-of-exercise-duration-and-recovery-type
#4
Luis F Barbosa, Benedito S Denadai, Camila C Greco
Slow component of oxygen uptake (VO2SC) kinetics and maximal oxygen uptake (VO2max) attainment seem to influence endurance performance during constant-work rate exercise (CWR) performed within the severe intensity domain. In this study, it was hypothesized that delaying the attainment of VO2max by reducing the rates at which VO2 increases with time (VO2SC kinetics) would improve the endurance performance during severe-intensity intermittent exercise performed with different work:recovery duration and recovery type in active individuals...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27993287/addition-of-vitamin-b12-to-exercise-training-improves-cycle-ergometer-endurance-in-advanced-copd-patients-a-randomized-and-controlled-study
#5
Fernanda Viana Paulin, Alessandro Moura Zagatto, Gaspar R Chiappa, Paulo de Tarso Müller
Vitamin B12 is essential in the homocysteine, mitochondrial, muscle and hematopoietic metabolisms, and its effects on exercise tolerance and kinetics adjustments of oxygen consumption (V'O2p) in rest-to-exercise transition in COPD patients are unknown. This randomized, double-blind, controlled study aimed to verify a possible interaction between vitamin B12 supplementation and these outcomes. After recruiting 69 patients, 35 subjects with moderate-to-severe COPD were eligible and 32 patients concluded the study, divided into four groups (n = 8 for each group): 1...
January 2017: Respiratory Medicine
https://www.readbyqxmd.com/read/27979503/effect-of-physical-training-on-the-recovery-of-acute-exercise-among-patients-with-cardiovascular-disease
#6
Marianna García-Saldivia, Hermes Ilarraza-Lomelí, Jonathan Myers, Jorge Lara, Leopoldo Bueno
INTRODUCTION: Physical training programs (PTP) have shown several beneficial effects for patients with cardiovascular disease (CVD), particularly by increasing survival and quality of life. Physiological response during the effort and recovery phases of an exercise testing, is one of the strongest prognostic markers among patients with CVD. A reasonable mechanism that explains those training effects on survival is through the adaptations seen on heart rate recovery (HRR) and oxygen uptake kinetics at the post-exertional phase (RVO2)...
December 12, 2016: Archivos de Cardiología de México
https://www.readbyqxmd.com/read/27951646/phe28-b10-induces-channel-forming-cytotoxic-amyloid-fibrillation-in-human-neuroglobin-the-brain-specific-hemoglobin
#7
Sheetal Uppal, Amit Kumar Singh, Richa Arya, Debanjan Tewari, Neha Jaiswal, Abhijeet Kapoor, Amal Kanti Bera, Alo Nag, Suman Kundu
Since its discovery, neuroglobin (Ngb), a neuron-specific oxygen binding hemoglobin, distinct from the classical myoglobin and blood hemoglobin, has attracted attention as an endogenous neuroprotectant. Recent reports suggest that Ngb protects neurons from brain stroke, ischemic stress-induced degeneration, and other brain disorders. Proteins with a specific role in neuroprotection are often associated with neurodegeneration, as well, depending on the cellular environment or specific cellular triggers that tilt the balance one way or the other...
December 13, 2016: Biochemistry
https://www.readbyqxmd.com/read/27920767/ecophysiology-and-comparative-genomics-of-nitrosomonas-mobilis-ms1-isolated-from-autotrophic-nitrifying-granules-of-wastewater-treatment-bioreactor
#8
Soe Myat Thandar, Norisuke Ushiki, Hirotsugu Fujitani, Yuji Sekiguchi, Satoshi Tsuneda
Ammonia-oxidizing bacteria (AOB), which oxidize ammonia to nitrite in the first step of nitrification, play an important role in biological wastewater treatment systems. Nitrosomonas mobilis is an important and dominant AOB in various wastewater treatment systems. However, the detailed physiological and genomic properties of N. mobilis have not been thoroughly investigated because of limited success isolating pure cultures. This study investigated the key physiological characteristics of N. mobilis Ms1, which was previously isolated into pure culture from the nitrifying granules of wastewater treatment bioreactor...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27904989/respirometric-response-and-microbial-succession-of-nitrifying-sludge-to-m-cresol-pulses-in-a-sequencing-batch-reactor
#9
Alberto Ordaz, Mariana Sánchez, Rodrigo Rivera, Rafael Rojas, Alejandro Zepeda
A nitrifying consortium was kinetically, stoichiometrically and molecularly characterized via the in situ pulse respirometric method and pyrosequencing analysis before and after the addition of m-cresol (25 mg C L(-1)) in a sequencing batch reactor (SBR). Five important kinetic and stoichiometric parameters were determined: the maximum oxygen uptake rate, the maximum nitrification rate, the oxidation yield, the biomass growth yield, and the substrate affinity constant. An inhibitory effect was observed in the nitrification process with a recovery of this by up to eight SBR cycles after m-cresol was added to the system...
November 30, 2016: Biodegradation
https://www.readbyqxmd.com/read/27825150/oxygen-uptake-recovery-kinetics-after-the-6-minute-walk-test-in-patients-with-chronic-obstructive-pulmonary-disease
#10
Florent Baty, Arnoldus J R van Gestel, Lukas Kern, Martin H Brutsche
BACKGROUND: There is a growing interest in exercise parameters capable of objectively evaluating the functional capacity of patients with chronic obstructive pulmonary disease (COPD). OBJECTIVES: The purpose of the present study was to analyze breath-by-breath cardiopulmonary and gas exchange recovery responses of patients with COPD after a 6-minute walk test (6MWT). METHODS: Oxygen uptake (VO2) kinetics of patients were obtained using mobile telemetric cardiopulmonary monitoring during and after a 6MWT...
2016: Respiration; International Review of Thoracic Diseases
https://www.readbyqxmd.com/read/27819153/faster-heart-rate-and-muscular-oxygen-uptake-kinetics-in-type-2-diabetes-patients-following-endurance-training
#11
Jessica Koschate, Uwe Drescher, Christian Brinkmann, Klaus Baum, Thorsten Schiffer, Joachim Latsch, Klara Brixius, Uwe Hoffmann
Cardiorespiratory kinetics were analyzed in type 2 diabetes patients before and after a 12-week endurance exercise-training intervention. It was hypothesized that muscular oxygen uptake and heart rate (HR) kinetics would be faster after the training intervention and that this would be detectable using a standardized work rate protocol with pseudo-random binary sequences. The cardiorespiratory kinetics of 13 male sedentary, middle-aged, overweight type 2 diabetes patients (age, 60 ± 8 years; body mass index, 33 ± 4 kg·m(-2)) were tested before and after the 12-week exercise intervention...
November 2016: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/27816527/comprehensive-study-of-hexarhenium-cluster-complex-na4-re6te8-cn-6-in-terms-of-a-new-promising-luminescent-and-x-ray-contrast-agent
#12
Anna A Krasilnikova, Anastasiya O Solovieva, Anton A Ivanov, Kristina E Trifonova, Tatyana N Pozmogova, Alphiya R Tsygankova, Anton I Smolentsev, Evgeniy I Kretov, David S Sergeevichev, Michael A Shestopalov, Yuri V Mironov, Alexander M Shestopalov, Alexander F Poveshchenko, Lidiya V Shestopalova
Octahedral rhenium cluster complexes may have considerable potential as therapeutic and diagnostic drugs due to their luminescent and X-ray contrast properties, as well as their ability to generate singlet oxygen upon photoirradiation. However, their potential biological effects and toxicity in vitro and in vivo are rather far from being understood. Thus, the aim of our research was to study cytotoxicity, intracellular localization and cellular uptake/elimination kinetics in vitro, biodistribution and acute intravenous toxicity in vivo of a complex Na4[{Re6Te8}(CN)6] as the promising compound for biomedical application...
November 2, 2016: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/27793061/cardiorespiratory-kinetics-determined-by-pseudo-random-binary-sequences-comparisons-between-walking-and-cycling
#13
J Koschate, U Drescher, L Thieschäfer, O Heine, K Baum, U Hoffmann
This study aims to compare cardiorespiratory kinetics as a response to a standardised work rate protocol with pseudo-random binary sequences between cycling and walking in young healthy subjects. Muscular and pulmonary oxygen uptake (V̇O2) kinetics as well as heart rate kinetics were expected to be similar for walking and cycling. Cardiac data and V̇O2 of 23 healthy young subjects were measured in response to pseudo-random binary sequences. Kinetics were assessed applying time series analysis. Higher maxima of cross-correlation functions between work rate and the respective parameter indicate faster kinetics responses...
December 2016: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/27790156/locomotor-muscle-fatigue-does-not-alter-oxygen-uptake-kinetics-during-high-intensity-exercise
#14
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/27787608/the-constant-work-rate-critical-power-protocol-overestimates-ramp-incremental-exercise-performance
#15
Matthew I Black, Andrew M Jones, James A Kelly, Stephen J Bailey, Anni Vanhatalo
PURPOSE: The parameters of the power-duration relationship (i.e., the critical power, CP, and the curvature constant, W') may theoretically predict maximal performance capability for exercise above the CP. The CP and W' are associated with the parameters of oxygen uptake ([Formula: see text]O2) kinetics, which can be altered by manipulation of the work-rate forcing function. We tested the hypothesis that the CP and W' derived from constant work-rate (CWR) prediction trials would overestimate ramp incremental exercise performance...
December 2016: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/27786541/postexercise-cold-water-immersion-improves-intermittent-high-intensity-exercise-performance-in-normothermia
#16
Avina McCarthy, James Mulligan, Mikel Egaña
A brief cold water immersion between 2 continuous high-intensity exercise bouts improves the performance of the latter compared with passive recovery in the heat. We investigated if this effect is apparent in normothermic conditions (∼19 °C), employing an intermittent high-intensity exercise designed to reflect the work performed at the high-intensity domain in team sports. Fifteen young active men completed 2 exhaustive cycling protocols (Ex1 and Ex2: 12 min at 85% ventilatory threshold (VT) and then an intermittent exercise alternating 30-s at 40% peak power (Ppeak) and 30 s at 90% Ppeak to exhaustion) separated by 15 min of (i) passive rest, (ii) 5-min cold-water immersion at 8 °C, and (iii) 10-min cold-water immersion at 8 °C...
November 2016: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/27784687/dietary-nitrate-supplementation-and-exercise-tolerance-in-patients-with-heart-failure-with-reduced-ejection-fraction
#17
Daniel M Hirai, Joel T Zelt, Joshua H Jones, Luiza G Castanhas, Robert F Bentley, Wendy Earle, Patti Staples, Michael E Tschakovsky, John McCans, Denis E O'Donnell, J Alberto Neder
Endothelial dysfunction and reduced nitric oxide (NO) signaling are key abnormalities leading to skeletal muscle oxygen delivery-utilization mismatch and poor physical capacity in patients with heart failure with reduced ejection fraction (HFrEF). Oral inorganic nitrate supplementation provides an exogenous source of NO that may enhance locomotor muscle function and oxygenation with consequent improvement in exercise tolerance in HFrEF. Thirteen patients (left ventricular ejection fraction ≤40%) were enrolled in a double-blind, randomized crossover study to receive concentrated nitrate-rich (nitrate) or nitrate-depleted (placebo) beetroot juice for 9 days...
January 1, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/27777059/metabolic-mechanisms-of-vocal-fatigue
#18
Chayadevie Nanjundeswaran, Jessie VanSwearingen, Katherine Verdolini Abbott
OBJECTIVE: This study aimed to identify potential metabolic mechanisms including (1) neuromuscular inefficiency, (2) cardiovascular recovery deficits, or (3) both, in individuals with complaints of vocal fatigue. STUDY DESIGN: Within- and between-subjects group design was used in this study. METHODS: Three groups of women participated in the study, including (1) individuals with complaints of vocal fatigue; (2) vocally healthy sedentary individuals; and (3) vocally healthy, cardiovascularly conditioned individuals...
October 21, 2016: Journal of Voice: Official Journal of the Voice Foundation
https://www.readbyqxmd.com/read/27765748/limitations-of-skeletal-muscle-oxygen-delivery-and-utilization-during-moderate-intensity-exercise-in-moderately-impaired-patients-with-chronic-heart-failure
#19
Victor M Niemeijer, Ruud F Spee, Thijs Schoots, Pieter F F Wijn, Hareld M C Kemps
The extent and speed of transient skeletal muscle deoxygenation during exercise onset in patients with chronic heart failure (CHF) are related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired patients with CHF (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-min exercise tests (bouts 1 and 2) with measurements of pulmonary oxygen uptake kinetics and SmO2 using near-infrared spatially resolved spectroscopy at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics...
December 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27748598/probing-the-heterogeneous-ozonolysis-of-squalene-nanoparticles-by-photoemission
#20
Michael I Jacobs, Bo Xu, Oleg Kostko, Nadja Heine, Musahid Ahmed, Kevin R Wilson
The heterogeneous reaction of ozone (O3) with 200 nm squalene nanoparticles is studied using near edge X-ray absorption fine structure (NEXAFS), ultraviolet (UPS) and X-ray photoelectron spectroscopy (XPS). Photoelectrons are detected from free nanoparticle beams using a velocity map imaging (VMI) spectrometer capable of detecting photoelectrons with up to 40 eV of kinetic energy. Heterogeneous kinetics are quantified using changes in the UPS, XPS and NEXAFS spectrum, yielding uptake coefficients for the decay of the double bonds in squalene of (3...
October 17, 2016: Journal of Physical Chemistry. A
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