Search Results
Results 201 - 250 of 1112
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Spolyar Douglas - - 2008
A mechanism is identified whereby dark matter (DM) in protostellar halos dramatically alters the current theoretical framework for the formation of the first stars. Heat from neutralino DM annihilation is shown to overwhelm any cooling mechanism, consequently impeding the star formation process and possibly leading to a new stellar phase. ...
Rowland Thomas - - 2008
PURPOSE: Physiological responses to exercise in the heat differ between prepubertal children and young adults. Whether these maturity-related variations imply lower exercise tolerance, inferior thermoregulation, and greater risk for heat injury in the child is uncertain. This study directly compared thermoregulatory and cardiovascular responses as well as endurance performance between ...
Barwood Martin J - - 2008
INTRODUCTION: Fatigue occurs earlier when working at corresponding exercise intensities in hot compared with cool conditions. Psychological skills training (PST) can modify the responses evoked by thermal stimuli such as the respiratory responses on immersion to cold water. This study tested the hypothesis that a 4-d PST package would significantly ...
Leung May S F MS Physiotherapy Department, Our Lady of Maryknoll Hospital, Hong - - 2008
To determine whether the addition of deep or superficial heating to stretching produces better clinical outcomes than stretching alone in the management of frozen shoulder. A single-blinded, randomized controlled study. Thirty subjects suffering from the stiffness phase of frozen shoulder. Subjects were randomly allocated to receive: (i) deep heating plus ...
Kacin Alan - - 2008
Heat-loss responses during steady-load exercise are affected by an increase in relative work rate induced by muscle ischaemia or hypoxaemia. The present study investigated whether progressive increases in perception of exertion and relative oxygen uptake %VO2peak which occur during prolonged steady-load exercise as a result of progressively increased peripheral fatigue, ...
Bonde Pramod - - 2008
OBJECTIVE: Thoracoscopic sympathectomy has become an accepted therapeutic option for palmar hyperhidrosis. Objective assessment of sweat output after sympathectomy, however, has not been reported to date. We report for the first time sweat output measurements after sympathectomy during a 3-year postoperative period. METHODS: Thoracoscopic sympathectomy was performed by division of ...
Senthilkumar Sivaprakasam - - 2008
This study is focused on the biodegradation of saline tannery effluent by identified halotolerant bacterial consortia in a bench-scale reaction calorimeter. A satisfactory agreement was observed between oxygen uptake rate profiles and heat flux-time curves confirming that, under strict aerobic conditions, calorimetry and respirometry provided the same information. Oxycalorific equivalent ...
Simmons Shona E - - 2008
The capacity to perform exercise is reduced in a hot environment when compared to cooler conditions. A limiting factor appears to be a higher core body temperature (T (core)) and it has been suggested that an elevated T (core) reduces the drive to exercise, this being reflected in higher ratings ...
Marino Frank E - - 2008
The evolutionary history of mammals, but more specifically humans, indicates that heat stress was a decisive and powerful selection pressure. There is good evidence that early hominids had to adapt to a changing environment by assuming an upright posture and consequently bipedalism. Because of further distances between food sources and ...
Whitham Martin - - 2008
The cumulative stressors of exercise manifest themselves at a cellular level by threatening the protein homeostasis of the cell. In these conditions, Heat Shock Proteins (HSP) are synthesised to chaperone mis-folded and denatured proteins. As such, the intracellular HSP response is thought to aid cell survival in the face of ...
Harmsze Ankie M - - 2008
The aim of this study was to develop a model to evaluate the efficacy of drugs with expected sweat-reducing properties in healthy subjects in order to select candidate drugs for the systemic treatment of primary generalized hyperhidrosis. A randomized, double-blind, placebo-controlled cross-over study was performed in 8 healthy subjects. Sweating ...
Lambert G Patrick - - 2008
Reduced intestinal blood flow and high intestinal temperatures during exercise-heat stress can lead to intestinal barrier dysfunction. Such dysfunction may increase intestinal permeability to endotoxin. During exercise-heat stress, intestinal barrier dysfunction and endotoxemia can produce gastrointestinal symptoms and increased production of pro-inflammatory cytokines. Such problems may be a warning sign ...
Tucker Ross - - 2008
There are a number of studies which have utilised exercise protocols where subjects are free to vary the work rate rather than having it externally imposed as is the case in fixed intensity exercise. These studies have demonstrated that exercise performance is regulated in advance of an excessive rise in ...
Thambirajah Anita A - - 2008
PURPOSE: Since physical exertion is known to exacerbate the symptoms of chronic fatigue syndrome (CFS) and metabolic changes and including oxidative stress can modulate heat shock protein (HSP) expression responses, we sought to determine whether HSP expression is altered in CFS patients before and after exercise. Heat shock proteins (HSPs) ...
Bates Graham P - - 2008
Significant and poorly documented electrolyte losses result from prolonged sweating. This study aimed to quantify likely sodium losses during work in heat. Male subjects exercised in an environmental chamber on two consecutive days in both winter and summer. Sweat collecting devices were attached to the upper arms and legs. Sweat ...
Enstipp Manfred R - - 2008
Diving endotherms inhabiting polar regions face potentially high thermoregulatory costs. Unless properly insulated, these animals will lose vast amounts of heat when diving in cold water, which has to be balanced by heat production. Heat generated as a by-product of digestion (heat increment of feeding, HIF) or from exercising muscles ...
Duffield Rob - - 2008
The aim of this chapter is to review the literature on the use of cooling interventions in the protection of and recovery of performance from exercise-induced heat stress. This chapter will deal primarily with the effects of pre-cooling on the improvement in exercise performance and the effects of post-exercise cooling ...
Short Rebecca W - - 2008
To assess the effect of exercise-induced sweat on truncal acne, a prospective, single-blinded, randomized, controlled, institution review board-approved clinical trial was conducted on physically active males. Subjects were instructed to exercise long enough to break a sweat 5 days a week for 2 weeks. Group 1 did not exercise (n ...
Hahn Robert G - - 2008
BACKGROUND AND OBJECTIVES: There is a need for simple method allowing detection of dehydration and hypovolemia. Based on a new theory of homeostatic blood states, we hypothesized that hemodilution following standardized crystalloid fluid bolus can be used to discriminate between baseline normohydration and dehydration, also normovolemia and hypovolemia. METHODS: Computer ...
van Houte Marthe - - 2008
OBJECTIVES: Oxybutynin has been proven to be effective in patients with generalized hyperhidrosis. Some dermatoses aggravate as a result of sweating. Therefore, oxybutynin might also be useful in such normohidrotic patients. The aim was to evaluate the efficacy and safety of different doses of oxybutynin on exercise-induced sweating in healthy ...
Mündel Toby - - 2008
Apart from few studies, the majority of the research conducted on the effects of heat stress on energy metabolism during exercise has only been done so in the past two decades. Whilst increasing exercise duration under conditions of heat stress favours the oxidation of carbohydrate (CHO) and appears to increase ...
Grahn Dennis A - - 2008
BACKGROUND: Many individuals afflicted with multiple sclerosis (MS) experience a transient worsening of symptoms when body temperature increases due to ambient conditions or physical activity. Resulting symptom exacerbations can limit performance. We hypothesized that extraction of heat from the body through the subcutaneous retia venosa that underlie the palmar surfaces ...
Hadjicharalambous Marios - - 2008
BACKGROUND: The present experiment examined the responses of peripheral modulators and indices of brain serotonin (5-HT) and dopamine (DA) function and their association with perception of effort during prolonged exercise in the heat after creatine (Cr) supplementation. METHODS: Twenty one endurance-trained males performed, in a double-blind fashion, two constant-load exercise ...
Sandström Marie E - - 2008
The purpose of this study was to investigate the alterations in serum heat shock protein (Hsp) 70 levels during a 15-consecutive-day intermittent heat-exercise protocol in a 29-year-old male ultra marathon runner. Heat acclimation, for the purpose of physical activities in elevated ambient temperatures, has numerous physiological benefits including mechanisms such ...
Roemer E - - 2008
The effects of the addition of ammonium magnesium phosphate (AMP) to the paper of an electrically heated cigarette (EHC) prototype on smoke composition and toxicity were quantified and the underlying mechanisms investigated. Smoke from EHC prototypes with and without AMP and from conventional cigarettes, i.e. the University of Kentucky Standard ...
Machado-Moreira Christiano A - - 2008
Thermal sweating from the human torso accounts for about half of the whole-body sweat secretion, yet its intra-segmental distribution has not been thoroughly examined. Therefore, the aim of the current study was to provide a detailed description of the distribution of eccrine sweating within the torso during passively-induced (water-perfusion garment: ...
Machado-Moreira Christiano A - - 2008
The importance of the head in dissipating body heat under hot conditions is well recognised, although very little is known about local differences in sweat secretion across the surface of the head. In this study, we focused on the intra-segmental distribution of head sweating. Ten healthy males were exposed to ...
Rowland Thomas - - 2008
Children possess certain physiological and anatomic characteristics that have traditionally been considered to impair thermoregulatory responses to exercise in the heat: low exercise economy, high ratio of body surface area to mass, diminished sweating capacity, and less cardiac output at the same work load compared with adults. Consequently, children have ...
Bishop David - - 2009
This study examined the effects of active warm up on thermoregulatory responses and intermittent-sprint cycle performance in hot conditions (35.5+/-0.6 degrees C, RH 48.7+/-3.4%). Eight trained males performed a 36-min, intermittent-sprint test (IST) after no (WUP 0), 10-min (WUP 10) or 20-min warm up (WUP 20). The IST contained 2-min ...
Montain Scott J - - 2007
CONTEXT: Uncertainty exists regarding the effect of sustained sweating on sweat mineral-element composition. PURPOSE: To determine the effect of multiple hours of exercise-heat stress on sweat mineral concentrations. METHODS: Seven heat-acclimated subjects (6 males, 1 female) completed 5 x 60 min of treadmill exercise (1.56 m/s, 2% grade) with 20 ...
Lovvorn J R - - 2007
For diving endotherms, modelling costs of locomotion as a function of prey dispersion requires estimates of the costs of diving to different depths. One approach is to estimate the physical costs of locomotion (Pmech) with biomechanical models and to convert those estimates to chemical energy needs by an aerobic efficiency ...
Wilson Robbie S - - 2007
The mating system of eastern mosquito fish (Gambusia holbrooki) is dominated by male sexual coercion, where all matings are forced and females never appear to cooperate and actively avoid all attempts. Previous research has shown that male G. holbrooki offer a model system for examining the benefits of reversible thermal ...
Hu Zhenhu - - 2008
Radio-frequency (RF)-based dielectric heating was used in the alkali (NaOH) pretreatment of switchgrass to enhance its enzymatic digestibility. Due to the unique features of RF heating (i.e., volumetric heat transfer, deep heat penetration of the samples, etc.), switchgrass could be treated on a large scale, high solid content, and uniform ...
Brotherhood John R - - 2008
Heat stress arising from the thermal environment is of concern to sports medicine and to sports administration because of the perceived risk of heat casualties, in particular heat stroke. Many sports organizations recommend environmental indices such as the WBGT for assessing risk and setting environmental limits for training and competition. ...
McClung James P JP US Army Research Institute of Environmental Medicine, Natick, MA, - - 2008
The induction of cellular acquired thermal tolerance (ATT) during heat acclimation (HA) in humans is not well described. This study determined whether exercise-HA modifies the human heat shock protein (HSP)72 and HSP90 responses and whether changes are correlated with physiological adaptations to HA. Using a 10-day HA protocol comprising daily ...
Murray Bob - - 2007
There is a rich scientific literature regarding hydration status and physical function that began in the late 1800s, although the relationship was likely apparent centuries before that. A decrease in body water from normal levels (often referred to as dehydration or hypohydration) provokes changes in cardiovascular, thermoregulatory, metabolic, and central ...
Lin Yan-Fu - - 2008
Runaway reactions by methyl ethyl ketone peroxide (MEKPO) are an important issue in Asia, due to its unstable structure and extensive heat release during upset situations. This study employed differential scanning calorimetry (DSC) to draw the experimental data for MEKPO 31 mass% and with acetone 99 mass% on three types ...
Weller Andrew S - - 2007
Compared with the induction of heat acclimation (HA), studies investigating the decay and re-induction of HA (RA) are relatively sparse and have yielded conflicting results. Therefore, 16 semi-nude men were acclimated to dry-heat by undertaking an exercise protocol in a hot chamber (dry-bulb temperature 46.1 +/- 0.1 degrees C; relative ...
González-Alonso José - - 2008
Exercise in the heat can pose a severe challenge to human cardiovascular control, and thus the provision of oxygen to exercising muscles and vital organs, because of enhanced thermoregulatory demand for skin blood flow coupled with dehydration and hyperthermia. Cardiovascular strain, typified by reductions in cardiac output, skin and locomotor ...
Sihoe Alan D L - - 2007
We report the case of a physically fit young man who presented with severe, life-threatening heat stroke after running a 10 km road race. He had previously received bilateral thoracic sympathectomy for axillary hyperhidrosis at another hospital, and was known to have upper body and limb anhidrosis. Thoracic sympathectomy can ...
Watkins Austen M - - 2007
INTRODUCTION: Acute bouts of heat stress and exercise have been shown to independently increase heat shock protein levels; however, the combination of these two stressors on HSP-72 expression in human skeletal muscle has not been established. The purpose of this study was to determine the effect of a bout of ...
Hargreaves Mark - - 2008
Exercise in the heat results in major alterations in cardiovascular, thermoregulatory, metabolic and neuromuscular function. Hyperthermia appears to be the key determinant of exercise performance in the heat. Thus, strategies that attenuate the rise in core temperature contribute to enhanced exercise performance. These include heat acclimatization, pre-exercise cooling and fluid ...
Maxwell Neil S - - 2008
This study compared two intensities of active recovery on intermittent sprint exercise performance and the development of heat strain in hot, humid conditions. Eight male game players completed four Cycling Intermittent Sprint Protocols (CISP) consisting of twenty 2-min periods, each including 10-s passive rest, 5-s maximal sprint against a resistance ...
Tilkens Michael J - - 2007
Numerous studies have discussed the influence of thermoregulation on hominin body shape concluding, in accordance with Allen's rule, that the presence of relatively short limbs on both extant as well as extinct hominin populations offers an advantage for survival in cold climates by reducing the limb's surface area to volume ...
Rikke Brad A - - 2007
Numerous physiological and molecular changes accompany dietary restriction (DR), which has been a major impediment to elucidating the causal basis underlying DR's many health benefits. Two major metabolic responses to DR that potentially underlie many of these changes are the body temperature (T(b)) and body weight (BW) responses. These responses ...
Kosmulski Marek - - 2007
The electrokinetic potential of powders dispersed in concentrated solutions of salts can be determined by electroacoustic methods when the ESA (electrokinetic sonic amplitude) signal of electrolyte is properly corrected for. We propose an alternative solution to the problem of electroacoustic measurements at high ionic strengths; that is, the composition of ...
Whitham Martin - - 2007
The contribution of heat and exercise related stress to the release of heat shock protein 72 (HSP72) is currently unknown. The purpose of the present study was to determine the combined and independent effects of heat and exercise on the extracellular (e)HSP72 response. Eleven moderately trained male volunteers [means +/- ...
Murray Bob - - 2007
This article summarizes a case of ischemic colitis suffered by a triathlete during an Ironman competition. Exercise results in a significant reduction in splanchnic blood flow to help maintain cardiovascular function. When dehydration and heat stress accompany exercise, blood flow to the splanchnic vasculature is further reduced, increasing the risk ...
Kenny Glen P - - 2007
Recovery from dynamic exercise results in significant perturbations of thermoregulatory control. These perturbations evoke a prolonged elevation in core body temperature and a concomitant decrease in sweating, skin blood flow, and skin temperature to pre-exercise baseline values within the early stages of recovery. Cutaneous vasodilation and sweating are critical responses ...
Cheung Stephen S - - 2007
Over the past decade, research interest has risen on the direct effects of temperature on exercise capacity and tolerance, particular in the heat. Two major paradigms have been proposed for how hyperthermia may contribute to voluntary fatigue during exercise in the heat. One suggests that voluntary exhaustion occurs upon the ...
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