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Oxygen uptake kinetics

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https://www.readbyqxmd.com/read/29570982/using-ramp-incremental-v%C3%AC-o2-responses-for-constant-intensity-exercise-selection
#1
Daniel A Keir, Donald H Paterson, John M Kowalchuk, Juan M Murias
Despite compelling evidence to the contrary, the view that oxygen uptake (V̇O2) increases linearly with exercise intensity (e.g. power output, speed) until reaching its maximum (V̇O2max) persists within the exercise physiology literature. This viewpoint implies that the V̇O2 response at any constant-intensity is predictable from a ramp-incremental exercise test. However, the V̇O2 versus task-specific exercise intensity relationship constructed from ramp-incremental versus constant-intensity exercise are not equivalent preventing the use of V̇O2 responses from one domain to predict those of the other...
March 23, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/29553736/molecular-mechanism-of-uptake-of-cationic-photoantimicrobial-phthalocyanine-across-bacterial-membranes-revealed-by-molecular-dynamics-simulations
#2
Philipp S Orekhov, Ekaterina G Kholina, Marine E Bozdaganyan, Alexey M Nesterenko, Ilya B Kovalenko, Marina G Strakhovskaya
Phthalocyanines are aromatic macrocyclic compounds, which are structurally related to porphyrins. In clinical practice phthalocyanines are used in fluorescence imaging and photodynamic therapy of cancer and non-cancer lesions. Certain forms of the substituted polycationic metallophthalocyanines have been previously shown to be active in photodynamic inactivation of both Gram-negative and Gram-positive bacteria, one of them is zinc octakis(cholinyl)phthalocyanine (ZnPcChol8+ ). However, the molecular details of how these compounds translocate across bacterial membranes still remain unclear...
March 19, 2018: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29541131/oxygen-delivery-is-not-a-limiting-factor-during-post-exercise-recovery-in-healthy-young-adults
#3
Robert T Mankowski, Victor M Niemeijer, Jasper P Jansen, Lotte Spraakman, Henk J Stam, Stephan F E Praet
Purpose: It is still equivocal whether oxygen uptake recovery kinetics are limited by oxygen delivery and can be improved by supplementary oxygen. The present study aimed to investigate whether measurements of muscle and pulmonary oxygen uptake kinetics can be used to assess oxygen delivery limitations in healthy subjects. Methods: Sixteen healthy young adults performed three sub-maximal exercise tests (6 min at 40% Wmax ) under hypoxic (14%O2 ), normoxic (21%O2 ) and hyperoxic (35%O2 ) conditions on separate days in randomized order...
June 2017: Journal of Exercise Science and Fitness
https://www.readbyqxmd.com/read/29533156/sex-differences-in-wheelchair-propulsion-biomechanics-and-mechanical-efficiency-in-novice-young-able-bodied-adults
#4
Dhissanuvach Chaikhot, Matthew J D Taylor, Florentina J Hettinga
An awareness of sex differences in gait can be beneficial for detecting the early stages of gait abnormalities that may lead to pathology. The same may be true for wheelchair propulsion. The aim of this study was to determine the effect of sex on wheelchair biomechanics and mechanical efficiency in novice young able-bodied wheelchair propulsion. Thirty men and 30 women received 12  min of familiarisation training. Subsequently, they performed two 10-m propulsion tests to evaluate comfortable speed (CS). Additionally, they performed a 4-min submaximal propulsion test on a treadmill at CS, 125% and 145% of CS...
March 13, 2018: European Journal of Sport Science
https://www.readbyqxmd.com/read/29525330/post-exercise-oxygen-uptake-recovery-delay-a-novel-index-of-impaired-cardiac-reserve-capacity-in-heart-failure
#5
Cole S Bailey, Luke T Wooster, Mary Buswell, Sarvagna Patel, Paul P Pappagianopoulos, Kristian Bakken, Casey White, Melissa Tanguay, Jasmine B Blodgett, Aaron L Baggish, Rajeev Malhotra, Gregory D Lewis
OBJECTIVES: This study sought to characterize the functional and prognostic significance of oxygen uptake (VO2 ) kinetics following peak exercise in individuals with heart failure (HF). BACKGROUND: It is unknown to what extent patterns of VO2 recovery following exercise reflect circulatory response during exercise in HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF). METHODS: We investigated patients (30 HFpEF, 20 HFrEF, and 22 control subjects) who underwent cardiopulmonary exercise testing with invasive hemodynamic monitoring and a second distinct HF cohort (n = 106) who underwent noninvasive cardiopulmonary exercise testing with assessment of long-term outcomes...
March 1, 2018: JACC. Heart Failure
https://www.readbyqxmd.com/read/29517834/properties-of-the-vastus-lateralis-muscle-in-relation-to-age-and-physiological-function-in-master-cyclists-aged-55-79-years
#6
Ross D Pollock, Katie A O'Brien, Lorna J Daniels, Kathrine B Nielsen, Anthea Rowlerson, Niharika A Duggal, Norman R Lazarus, Janet M Lord, Andrew Philp, Stephen D R Harridge
In this study, results are reported from the analyses of vastus lateralis muscle biopsy samples obtained from a subset (n = 90) of 125 previously phenotyped, highly active male and female cyclists aged 55-79 years in regard to age. We then subsequently attempted to uncover associations between the findings in muscle and in vivo physiological functions. Muscle fibre type and composition (ATPase histochemistry), size (morphometry), capillary density (immunohistochemistry) and mitochondrial protein content (Western blot) in relation to age were determined in the biopsy specimens...
March 8, 2018: Aging Cell
https://www.readbyqxmd.com/read/29479342/adaptation-to-aerobic-environment-of-lactobacillus-johnsonii-gasseri-strains
#7
Diamante Maresca, Teresa Zotta, Gianluigi Mauriello
Oxygen is considered one of the main factors affecting probiotic bacteria survival due to the induction of oxidative damages caused by the action of reactive oxygen species (ROS). It has been shown that oxidative stress resistance in lactic acid bacteria is strongly dependent on the type of cell metabolism. Shift from fermentative to respiratory metabolism (through the addition of heme and menaquinone and in presence of oxygen) was associated to increase in biomass, long-term survival, and production of antioxidant enzymes...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29474423/seasonal-variability-in-the-persistence-of-dissolved-environmental-dna-edna-in-a-marine-system-the-role-of-microbial-nutrient-limitation
#8
Ian Salter
Environmental DNA (eDNA) can be defined as the DNA pool recovered from an environmental sample that includes both extracellular and intracellular DNA. There has been a significant increase in the number of recent studies that have demonstrated the possibility to detect macroorganisms using eDNA. Despite the enormous potential of eDNA to serve as a biomonitoring and conservation tool in aquatic systems, there remain some important limitations concerning its application. One significant factor is the variable persistence of eDNA over natural environmental gradients, which imposes a critical constraint on the temporal and spatial scales of species detection...
2018: PloS One
https://www.readbyqxmd.com/read/29394491/impact-of-l-citrulline-supplementation-on-oxygen-uptake-kinetics-during-walking
#9
John Ashley, Youngdeok Kim, Joaquin U Gonzales
Supplementation with L-citrulline (Cit) has been shown to improve muscle oxygenation and oxygen uptake (VO2) kinetics during moderate-to-high intensity cycling in young men. The aim of this study was to test the hypothesis whether Cit would improve VO2 kinetics during walking in older and young adults. In a randomized, double-blind study, 26 (15 women, 11 men) adults between the ages of 20-35y (n = 15) and 64-86y (n = 11) completed 7 day periods of taking placebo and L-citrulline (6 g/day) in a crossover manner...
February 2, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/29334615/hemodynamic-and-metabolic-responses-to-self-paced-and-ramp-graded-exercise-testing-protocols
#10
Nicholas M Beltz, Fabiano T Amorim, Ann L Gibson, Jeffrey M Janot, Len Kravitz, Christine M Mermier, Nathan Cole, Terence A Moriarty, Tony P Nunez, Sam Trigg, Lance C Dalleck
Recent examinations have shown lower maximal oxygen consumption during traditional ramp (RAMP) compared with self-paced (SPV) graded exercise testing (GXT) attributed to differences in cardiac output. The current study examined the differences in hemodynamic and metabolic responses between RAMP and SPV during treadmill exercise. Sixteen recreationally trained men (aged23.7 ± 3.0 years) completed 2 separate treadmill GXT protocols. SPV consisted of five 2-min stages (10 min total) of increasing speed clamped by the Borg RPE6-20 scale...
January 15, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
https://www.readbyqxmd.com/read/29331919/removal-of-pharmaceutical-pollutants-from-synthetic-wastewater-using-chemically-modified-biomass-of-green-alga-scenedesmus-obliquus
#11
Mohamed E M Ali, Azza M Abd El-Aty, Mohamed I Badawy, Rizka K Ali
Pharmaceutical compounds are considered emerging environmental pollutants that have a potential harmful impact on environment and human health. In this study, the biomass of alga (Scenedesmus obliquus) was modified using alkaline solution, and used for the biosorption of tramadol (TRAM) and other pharmaceuticals. The adsorption kinetics and isotherms were investigated. The obtained results reveal high adsorption capacity of tramadol over modified algal biomass (MAB) after 45min with removal percentage of 91%...
April 30, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29279000/oxygen-uptake-on-kinetics-during-six-minute-walk-test-predicts-short-term-outcomes-after-off-pump-coronary-artery-bypass-surgery
#12
Isadora Salvador Rocco, Marcela Viceconte, Hayanne Osiro Pauletti, Bruna Caroline Matos-Garcia, Natasha Oliveira Marcondi, Caroline Bublitz, Douglas William Bolzan, Rita Simone Lopes Moreira, Michel Silva Reis, Nelson Américo Hossne, Walter José Gomes, Ross Arena, Solange Guizilini
PURPOSE: We aimed to investigate the ability of oxygen uptake kinetics to predict short-term outcomes after off-pump coronary artery bypass grafting. METHODS: Fifty-two patients aged 60.9 ± 7.8 years waiting for off-pump coronary artery bypass surgery were evaluated. The 6-min walk test distance was performed pre-operatively, while simultaneously using a portable cardiopulmonary testing device. The transition of oxygen uptake kinetics from rest to exercise was recorded to calculate oxygen uptake kinetics fitting a monoexponential regression model...
December 26, 2017: Disability and Rehabilitation
https://www.readbyqxmd.com/read/29276855/assessing-differences-in-cardiorespiratory-fitness-with-respect-to-maturity-status-in-highly-trained-youth-soccer-players
#13
Greg Doncaster, John Iga, Viswanath Unnithan
PURPOSE: The purpose of the study was to examine differences in measures of cardiorespiratory fitness and determinants of running economy with respect to maturity status in a group of highly trained youth soccer players. METHODS: A total of 21 highly trained youth soccer players participated in this study. On separate visits, players' peak oxygen uptake (VO2peak ), running economy at 3 different speeds [8 km·h-1 , 80% gaseous exchange threshold (GET), and 95% GET], and pulmonary oxygen uptake (VO2 ) kinetics were determined...
December 23, 2017: Pediatric Exercise Science
https://www.readbyqxmd.com/read/29250707/non-invasive-estimation-of-muscle-oxygen-uptake-kinetics-with-pseudorandom-binary-sequence-and-step-exercise-responses
#14
Uwe Drescher, R Schmale, J Koschate, L Thieschäfer, T Schiffer, S Schneider, U Hoffmann
PURPOSE: The aim of the study was to test for significant differences in non-invasively estimated muscle oxygen uptake ([Formula: see text]) kinetics, assessed by a square-wave exercise protocol (STEP) as well as by a time series approach with pseudorandom binary sequence (PRBS) work rate (WR) changes. METHODS: Seventeen healthy and active individuals (10 women, 7 men; 23 ± 2 years old; height 175 ± 11 cm; body mass 73 ± 14 kg [mean ± SD]) completed five repetitions of WR transitions from 30 to 80 W for the STEP approach and two sequences of pseudorandom binary WR changes between 30 and 80 W for the PRBS approach...
February 2018: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/29239779/gender-differences-in-residual-effect-of-prior-drop-jumps-on-oxygen-uptake-during-heavy-cycling-exercise
#15
Neringa Baranauskienė, Sandra Kilikevičienė, Loreta Stasiulė, Genuvaitė Civinskienė, Arvydas Stasiulis
BACKGROUND AND OBJECTIVE: Unaccustomed eccentric or eccentric-concentric exercise leaves us stiff and sore the next day and can cause muscle damage. The data about the residual effect of prior eccentric-concentric exercises on oxygen uptake (VO2 ) during constant cycling exercise in women or the data about differences of such effect between genders are scarce. Therefore, the aim of this study was to assess differences of the residual effect of PDJ on VO2 during HCE and indirect muscle damage parameters between women and men...
December 2017: Medicina
https://www.readbyqxmd.com/read/29210688/the-importance-of-surface-functional-groups-in-the-adsorption-of-copper-onto-walnut-shell-derived-activated-carbon
#16
Ruzhen Xie, Yan Jin, Yao Chen, Wenju Jiang
In this study, activated carbon (AC) was prepared from walnut shell using chemical activation. The surface chemistry of the prepared AC was modified by introducing or blocking certain functional groups, and the role of the different functional groups involved in the copper uptake was investigated. The structural and chemical heterogeneity of the produced carbons are characterized by Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, Boehm titration method and N2 /77 K adsorption isotherm analysis...
December 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/29182413/energetic-profile-of-the-basketball-exercise-simulation-test-in-junior-elite-players
#17
Richard Latzel, Olaf Hoos, Sebastian Stier, Sebastian Kaufmann, Volker Fresz, Dominik Reim, Ralph Beneke
PURPOSE: To analyze the energetic profile of the basketball exercise simulation test (BEST). METHODS: 10 male elite junior basketball players (age: 15.5±0.6yrs, height: 180±9cm, body mass: 66.1±11.2kg) performed a modified BEST (20 circuits consisting of jumping, sprinting, jogging, shuffling, and short breaks) simulating professional basketball game play. Circuit time, sprint time, sprint decrement, oxygen uptake (VO2), heart rate (HR), and blood lactate concentration (BLC) were obtained...
November 28, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/29161578/probabilistic-pharmacokinetic-models-of-decompression-sickness-in-humans-part-2-coupled-perfusion-diffusion-models
#18
F Gregory Murphy, Ethan A Hada, David J Doolette, Laurens E Howle
Decompression sickness (DCS) can be experienced following a reduction in ambient pressure; such as that associated with diving or ascent to high altitudes. DCS is believed to result when supersaturated inert gas dissolved in biological tissues exits solution and forms bubbles. Models to predict the probability of DCS are typically based on nitrogen and/or helium gas uptake and washout in several theoretical tissues, each represented by a single perfusion-limited compartment. It has been previously shown that coupled perfusion-diffusion compartments are better descriptors than solely perfusion-based models of nitrogen and helium uptake and elimination kinetics observed in the brain and skeletal muscle of sheep...
January 1, 2018: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29157149/stabilized-landfill-leachate-treatment-using-guadua-amplexifolia-bamboo-as-a-source-of-activated-carbon-kinetics-study
#19
Bianka G Salas-Enríquez, Aidé M Torres-Huerta, Eloy Conde-Barajas, Miguel A Domínguez-Crespo, María L X Negrete-Rodríguez, Héctor J Dorantes-Rosales, Ana B López-Oyama
In the present study, the characteristics of leachate generated from dumpsite called 'Zapote' located in southern region of Tamaulipas, Mexico were evaluated. The adsorption of non-biodegradable organic matter measured as chemical oxygen demand (COD), color and heavy metals from leachate on activated carbon (AC) prepared in acid media from Guadua amplexifolia bamboo has been studied. In addition, the computation of kinetic parameters during the adsorption process as well as the most probable mechanisms was determined...
November 30, 2017: Environmental Technology
https://www.readbyqxmd.com/read/29154138/preparation-of-biochar-from-enteromorpha-prolifera-and-its-use-for-the-removal-of-polycyclic-aromatic-hydrocarbons-pahs-from-aqueous-solution
#20
Kaili Qiao, Weijun Tian, Jie Bai, Jie Dong, Jing Zhao, Xiaoxi Gong, Shuhui Liu
EP-biochar was produced from Enteromorpha prolifera (EP) at temperatures of 200-600°C under limited-oxygen conditions and then activated using HCl and HF. To optimize the sorption of pyrene (PYR) and benzo[a]pyrene (BaP), the effect of the pyrolysis temperature was studied, and the results showed that EP-biochar produced at 500°C gave the highest removal efficiency. The physiochemical properties of EP-biochar pyrolyzed at 500°C were characterized. The examination indicated that the surface area of EP-biochar was 205...
March 2018: Ecotoxicology and Environmental Safety
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