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Mujika Iñigo - - 2010
Team sports are based on intermittent high-intensity activity patterns, but the exact characteristics vary between and within codes, and from one game to the next. Despite the challenge of predicting exact game demands, performance in team sports is often dependent on nutritional factors. Chronic issues include achieving ideal levels of ...
Janssen C - - 2009
The contribution of the peripheral chemoreflex to the ventilatory response to exercise and aerobic exercise capacity remains incompletely understood. Low-dose dopamine has been reported to specifically inhibit the peripheral chemoreceptors. We therefore investigated the effects of intravenous dopamine (3 microg kg(-1)min(-1)) on cardiopulmonary exercise test (CPET) variables in 13 healthy ...
Wood Helen E - - 2009
INTRODUCTION: The effects of head-down rest (HDR) and microgravity on cardiovascular control have been widely studied; however, their effects on ventilatory control are less clear. An increased ventilatory response to exercise and/or to hypercapnia (HCVR) could cause significantly increased ventilatory demand and/or dyspnea, and thus limit the ability of flight ...
Kutsch Werner L - - 2008
Potential losses by advection were estimated at Hainich Forest, Thuringia, Germany, where the tower is located at a gentle slope. Three approaches were used: (1) comparing nighttime eddy covariance fluxes to an independent value of total ecosystem respiration by bottom-up modeling of the underlying processes, (2) direct measurements of a ...
Ekkekakis Panteleimon - - 2008
The determination of the ventilatory threshold has been a persistent problem in research and clinical practice. Several computerized methods have been developed to overcome the subjectivity of visual methods but it remains unclear whether different computerized methods yield similar results. The purpose of this study was to compare nine regression-based ...
Chapman Robert F - - 2008
INTRODUCTION/PURPOSE: Many athletes with exercise-induced hypoxemia (EIH) show an insufficient ventilatory response to exercise and low resting ventilatory responsiveness. The purpose of this project was to determine whether a moderate dosage of caffeine, a common ventilatory stimulant, could augment resting ventilatory responsiveness, exercise ventilation (V E), end-tidal O2 partial pressure ...
Brando Paulo M - - 2008
The Amazon Basin experiences severe droughts that may become more common in the future. Little is known of the effects of such droughts on Amazon forest productivity and carbon allocation. We tested the prediction that severe drought decreases litterfall and wood production but potentially has multiple cancelling effects on belowground ...
Lundgren, Claes E.
The objective of this Postdoctoral fellowship was to provide education to extend their training to embarking on an independent research. Two Postdoctoral Fellows were trained. Important safety issues of breath-holding and limitations to diver performance were studied. Two studies showed the potential for increased risk of loss of consciousness (LOC) ...
Leonenko Yuri - - 2008
It is possible to accelerate the dissolution of CO2 injected into deep aquifers by pumping brine from regions where it is undersaturated into regions occupied by CO2. For a horizontally confined reservoir geometry, we find that it is possible to dissolve most of the injected CO2 within a few hundred ...
Ekkekakis Panteleimon - - 2008
BACKGROUND: A causal chain linking exercise intensity, affective responses (e.g., pleasure-displeasure), and adherence has long been suspected as a contributor to the public health problem of physical inactivity. However, progress in the investigation of this model has been limited, mainly due to inconsistent findings on the first link between exercise ...
Kamakura Mai - - 2008
The responses of individual stomata to CO2 concentrations ranging from 0 to 900 micromol mol(-1) air were analysed in Ipomoea pes-caprae L. Sweet (Convolvulaceae). The stomata were directly observed using a measurement system that permitted continuous observation of stomatal movement under controlled light and CO2 conditions. A CO2 concentration of ...
Liu Peng - - 2008
The work function of carbon nanotubes might depend on their diameters and the number of walls, and be different for their tips and sidewalls. Here we report the work function measurement of single-walled, double-walled, and multiwalled carbon nanotubes by investigating the thermionic emission from the middle of their bundles. It ...
Tcherkez Guillaume - - 2008
Day respiration is the process by which nonphotorespiratory CO2 is produced by illuminated leaves. The biological function of day respiratory metabolism is a major conundrum of plant photosynthesis research: because the rate of CO2 evolution is partly inhibited in the light, it is viewed as either detrimental to plant carbon ...
Fuglestvedt Jan - - 2008
Although the transport sector is responsible for a large and growing share of global emissions affecting climate, its overall contribution has not been quantified. We provide a comprehensive analysis of radiative forcing from the road transport, shipping, aviation, and rail subsectors, using both past- and forward-looking perspectives. We find that, ...
Cathcart Andrew J - - 2008
Intermittent supra-maximal cycling of varying work: recovery durations was used to explore the kinetics of respiratory compensation for the metabolic acidosis of high-intensity exercise (> lactate threshold, thetaL). For a 10:20s duty-cycle, blood [lactate] ([L-]) was not increased, and there was no evidence of respiratory compensation (RC); i.e, no increase ...
Whipp Brian J - - 2007
This case report describes the responses to incremental work-rate exercise in a healthy subject (with normal pulmonary function), for whom the pulmonary gas exchange (V-slope) and ventilatory-related indexes (ie, ventilatory equivalents and end-tidal partial pressures for O2 and CO2) uncharacteristically do not occur at the same metabolic rate. Based on ...
Wood Helen E - - 2008
Arterial isocapnia is a hallmark of moderate exercise in humans and is maintained even when resting arterial Pco(2) (Pa(CO(2))) is raised or lowered from its normal level, e.g., with chronic acid-base changes or acute increases in respiratory dead space. When resting ventilation and/or Pa(CO(2)) are altered, maintenance of isocapnia requires ...
Jin Lan - - 2008
The sensitivity of cryoprobes, which are rapidly becoming available, have brought about the possibility of measurement of (13)C, (13)C coupling constants at the natural abundance of (13)C using tens rather than hundreds of milligrams of compounds. This relatively recent development lays the foundation for a more routine use of the ...
Turnbull Tarryn L - - 2007
Increased photosynthetic rates following partial defoliation may arise from changes in leaf biochemistry, water relations or nutrient status. Twelve-month-old field-grown Eucalyptus globulus Labill. seedlings were pruned from below to reduce the green crown depth by 50 (D50) or 70% (D70). Photosynthetic responses to light and CO2 concentration were examined before ...
Aström Elisabet - - 2008
OBJECTIVE: To avoid ventilator induced lung injury, tidal volume should be low in acute lung injury (ALI). Reducing dead space may be useful, for example by using a pattern of inspiration that prolongs the time available for gas distribution and diffusion within the respiratory zone, the mean distribution time (MDT). ...
Esquivel Gabriel - - 2008
BACKGROUND: Chronic exercise has been shown to have therapeutic effects in panic disorder (PD). The mechanism of these effects is unknown. Acute exercise reduces the effect of a panic challenge in healthy volunteers. Such an effect has not yet been demonstrated in PD patients. The present study aimed at exploring ...
Romero Steven A - - 2007
Hyperventilation performed by athletes during preparation for resistance exercise might contribute to reports of postexercise orthostatic instability. PURPOSE: To test the hypothesis that post-resistance exercise orthostatic instability is associated with exaggerated reductions of cerebral blood-flow velocity after hyperventilation. METHODS: We recorded the ECG, end-tidal CO2, beat-by-beat finger arterial pressure, and ...
Christensen T R - - 2007
This is the first attempt to budget average current annual carbon (C) and associated greenhouse gas (GHG) exchanges and transfers in a subarctic landscape, the Lake Torneträsk catchment in northern Sweden. This is a heterogeneous area consisting of almost 4000 km2 of mixed heath, birch and pine forest, and mires, ...
Mert Agali - - 2007
INTRODUCTION: In motion sickness desensitization programs, the motion sickness provocative stimulus is often a forward bending of the trunk on a rotating chair, inducing Coriolis effects. Since respiratory relaxation techniques are applied successfully in these courses, we investigated whether these repetitive trunk movements by themselves may induce hyperventilation and consequently ...
Tang Y - - 2007
BACKGROUND: Anatomical dead space is usually measured using the Fowler equal area method. Alternative methods include the Hatch, Cumming, and Bowes methods, in which first, second, and third order polynomials, respectively, fitted to an expired CO2 volume vs expired volume curve, intercept the x-axis at the anatomical dead space. This ...
Nettlefold Lindsay - - 2007
We examined the effect of menstrual cycle (MC) phase on acid-base regulation and ventilatory control at rest in monophasic oral contraceptive (OC) users. Twelve healthy women (25+/-1 years; mean+/-S.E.) were tested during the inactive (IP; 5.1+/-0.2 days) and active (AP; 21.1+/-0.7 days) pill phase of the MC. Central and peripheral ...
Ainsworth Elizabeth A - - 2007
This review summarizes current understanding of the mechanisms that underlie the response of photosynthesis and stomatal conductance to elevated carbon dioxide concentration ([CO2]), and examines how downstream processes and environmental constraints modulate these two fundamental responses. The results from free-air CO2 enrichment (FACE) experiments were summarized via meta-analysis to quantify ...
Ward Susan A - - 2007
Below the lactate threshold ((thetaL)), ventilation (V(E))responds in close proportion to CO(2) output to regulate arterial partial pressure of CO(2) (PaCO2). While ventilatory control models have traditionally included proportional feedback (central and carotid chemosensory) and feedforward (central and peripheral neurogenic) elements, the mechanisms involved remain unclear. Regardless, putative control schemes ...
Zuccarelli Micah D - - 2007
Motility of salmonid sperm is inhibited by the presence of carbon dioxide (CO2) in vitro; however, whether this occurs in response to challenges to the adult in vivo is not known. To determine whether CO2 negatively impacts sperm function in vivo, mature males were exposed to exhaustive exercise as well ...
Michalewicz Betty A - - 2007
We investigated ventilatory and metabolic demands in healthy adults when placed in the prone maximal restraint position (PMRP), i.e., hogtie restraint. Maximal voluntary ventilation (MVV) was measured in seated subjects (n=30), in the PMRP, and when prone with up to 90.1 or 102.3 kg of weight on the back. MVV ...
Werner Christiane - - 2007
Recent insights into fractionation during dark respiration and rapid dynamics in isotope signatures of leaf- and ecosystem-respired CO(2) indicate the need for new methods for high time-resolved measurements of the isotopic signature of respired CO(2) (delta(13)C(res)). We present a rapid and simple method to analyse delta(13)C(res) using an in-tube incubation ...
Martin Daniel - - 2007
Using automated air gastric tonometry, the hypothesis that gastric perfusion is reduced while exercising at high altitude was explored. This prospective observational study of 5 well acclimatized healthy volunteers was performed during a medical research expedition to Chamlang base camp (5000 m), Hongu valley, Nepal. We used gastric tonometry at ...
Thomas Vincent - - 2007
The aim of this study is to propose a new approach to estimate non-invasively arterial carbon dioxide partial pressure (P(a)CO2) approach was based on the reconstruction of alveolar gas composition over each breath from a tidally ventilated lung model (P(M)(CO2)). Eight healthy young subjects were studied during a ramp exercise ...
Day Trevor A - - 2007
Inputs from central (brainstem) and peripheral (carotid body) respiratory chemoreceptors are coordinated to protect blood gases against potentially deleterious fluctuations. However, the mathematics of the steady-state interaction between chemoreceptors has been difficult to ascertain. Further, how this interaction affects time-dependent phenomena (in which chemoresponses depend upon previous experience) is largely ...
Bhambhani Yagesh - - 2007
During incremental exercise PaCO2 and PETCO2 begin to decline at the respiratory compensation threshold (RCT-GEX). Since PaCO2 alters cerebral blood flow it was hypothesized that there would be a systematic decline in cerebral oxygenation (Cox) measured by near infrared spectroscopy above the RCT (RCT-NIRS). Cardiorespiratory and NIRS responses were simultaneously ...
Itoh Masahiro - - 2007
We studied the relationship between exercise hyperpnea (i.e., ventilatory dynamics) at the onset of exercise and hypercapnic ventilatory response (HCVR), and their differences between the follicular (FP) and luteal (LP) phases of the menstrual cycle in six healthy females. HCVR was tested under three O(2) conditions: hyperoxia (FiO(2)=1.0), normoxia (0.21), ...
Arena Ross - - 2007
BACKGROUND: The partial pressure of end-tidal carbon dioxide production (P(ET)CO2) at ventilatory threshold (VT) has been shown to be strongly correlated with cardiac output during exercise in patients with heart failure (HF), but few data are available regarding its prognostic utility. AIMS: The purpose of this study was to assess ...
Tipton M - - 2006
Hyperbaric Escape Systems (HES) are used when saturation diving bells have to be evacuated and divers transported to safety. The aim of the present investigation was to determine the levels of metabolic CO2 production expected from the occupants of an HES in different wave states, and from this, to recommend ...
Collins Sinéad - - 2006
Selective history is thought to constrain the extent and direction of future adaptation by limiting access to genotypes that are advantageous in a novel environment. Populations of Chlamydomonas previously selected at high CO2 were either backselected at ambient levels of CO2, or selected at levels of CO2 that last occurred ...
Dimopoulos Konstantinos - - 2006
BACKGROUND: Limited data exist with which to stratify risk in adult congenital heart disease (ACHD). An increased ventilatory response to exercise, expressed as ventilation per unit of carbon dioxide production (V(E)/V(CO2) slope), is an established predictor of impaired survival in acquired heart disease. We sought to establish the distribution, relation ...
Martino P F - - 2006
The purpose of this study was to test the hypothesis that an intact cerebellar fastigial nucleus (CFN) is necessary for the hyperpnea to meet the gas exchange needs of submaximal exercise. Bilateral stainless steel microtubules were implanted in the cerebellum inside (n = 12) or outside (n = 2) the ...
Gerritzen M A - - 2006
Large groups of poultry, including ducks and turkeys, are killed for disease control purposes with CO2. In this study, we examined the physiological reaction of White Pekin ducks and turkeys to increasing CO2 concentrations. Additionally, we examined the suitability of killing both species with increasing CO2 concentrations. Blood gas values ...
Li Wan - - 2006
We investigated the effects of anxiety on the intensity of air hunger during gradually increasing levels of CO2 until the end-tidal fractional concentration of CO2 was 7.9% or air hunger was intolerable. Normal high and low (trait) anxious participants (N=23) went through three rebreathing trials (15 min interval). Breathing behaviour ...
Zhang Jianmin - - 2006
Ecosystem-scale estimation of photosynthesis and respiration using micrometeorological techniques remains an important, yet difficult, challenge. In this study, we combined micrometeorological and stable isotope methods to partition net ecosystem CO2 exchange (FN) into photosynthesis (F(A)) and respiration (F(R)) in a corn-soybean rotation ecosystem during the summer 2003 corn phase. Mixing ...
Mitchell Gordon S - - 2006
Despite the fundamental biological significance of the ventilatory response to mild or moderate physical activity (the exercise hyperpnea), we still know remarkably little concerning its underlying mechanisms. Part of the difficulty in revealing those mechanisms may arise due to confusion between multiple mechanistic layers, each contributing to the impressive degree ...
Manolis Evangelos N - - 2006
BACKGROUND: Although beam-scanning carbon dioxide (CO2) lasers have provided a highly efficient tool for esthetic skin rejuvenation there has been no comprehensive animal studies looking into microbial skin changes following CO2 laser skin resurfacing. OBJECTIVE: To evaluate the in vivo effects of CO2 laser skin resurfacing in an experimental rat ...
Gheshmy Afshan - - 2006
Anuran amphibians have multiple populations of pH/CO2-sensitive respiratory-related chemoreceptors. This study examined in cane toads (Bufo marinus) whether chronic hypercapnia (CHC) altered the pH/CO2 sensitivity of central respiratory-related chemoreceptors in vitro and whether CHC altered the acute hypercapnic ventilatory response (HCVR; 5% CO2) in vivo. Toads were exposed to CHC ...
Hartzler L K - - 2006
A large alkaline tide (up to 20 mmol l(-1) increase in bicarbonate concentration [HCO3-] with an accompanied increase in blood pH) has previously been reported for some carnivorous reptiles within 24 h after ingesting a large meal. This phenomenon has been attributed to the secretion of large amounts of H+ ...
Wahl Ed H - - 2006
Recent measurements of carbon isotopes in carbon dioxide using near-infrared, diode-laser-based cavity ring-down spectroscopy (CRDS) are presented. The CRDS system achieved good precision, often better than 0.2 per thousand, for 4% CO2 concentrations, and also achieved 0.15-0.25 per thousand precision in a 78 min measurement time with cryotrap-based pre-concentration of ...
Péronnet François - - 2006
It has been suggested that hyperventilation and the disproportionate increase in VCO2 versus VO2 above the ventilatory threshold (V(TH)) in ramp exercise are due to the production of nonmetabolic CO2 in muscle because of lactic acid buffering by plasma bicarbonate entering the cell in exchange with lactate [Wasserman, K., 1982. ...
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