Effects of mild heat exposure on fatigue responses during two sets of repeated sprints matched for initial mechanical output

The effects of mild heat exposure (30�C; 30% relative humidity), and of the suppression of prolactin secretion under such conditions, were studied in anoestrous ewes given daily 791 g dry matter of a pelleted mixture of lucerne hay and oat grain (3: 2). 51Cr-EDTA, 103Ru-phenanthroline and lignin were used to determine mean retention times (MRT) in the gastro-intestinal (01) tract by a continuous infusion-total sampling procedure.

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Effects of mild heat exposure on sleep stages and body temperature in older men

International Journal of Biometeorology ◽

10.1007/s00484-004-0209-3 ◽

2004 ◽

Vol 49 (1) ◽

Cited By ~ 24

Author(s):

K. Okamoto-Mizuno ◽

K. Tsuzuki ◽

K. Mizuno

Keyword(s):

Body Temperature ◽

Heat Exposure ◽

Older Men ◽

Sleep Stages ◽

Mild Heat

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Regional differences in temperature sensation and thermal comfort in humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.90466.2008 ◽

2008 ◽

Vol 105 (6) ◽

pp. 1897-1906 ◽

Cited By ~ 97

Author(s):

Mayumi Nakamura ◽

Tamae Yoda ◽

Larry I. Crawshaw ◽

Saki Yasuhara ◽

Yasuyo Saito ◽

...

Keyword(s):

Thermal Comfort ◽

Cold Exposure ◽

Regional Differences ◽

Heat Exposure ◽

Major Effect ◽

Whole Body ◽

Mild Heat ◽

Temperature Sensation ◽

Body Regions ◽

The Face

Sensations evoked by thermal stimulation (temperature-related sensations) can be divided into two categories, “temperature sensation” and “thermal comfort.” Although several studies have investigated regional differences in temperature sensation, less is known about the sensitivity differences in thermal comfort for the various body regions. In the present study, we examined regional differences in temperature-related sensations with special attention to thermal comfort. Healthy male subjects sitting in an environment of mild heat or cold were locally cooled or warmed with water-perfused stimulators. Areas stimulated were the face, chest, abdomen, and thigh. Temperature sensation and thermal comfort of the stimulated areas were reported by the subjects, as was whole body thermal comfort. During mild heat exposure, facial cooling was most comfortable and facial warming was most uncomfortable. On the other hand, during mild cold exposure, neither warming nor cooling of the face had a major effect. The chest and abdomen had characteristics opposite to those of the face. Local warming of the chest and abdomen did produce a strong comfort sensation during whole body cold exposure. The thermal comfort seen in this study suggests that if given the chance, humans would preferentially cool the head in the heat, and they would maintain the warmth of the trunk areas in the cold. The qualitative differences seen in thermal comfort for the various areas cannot be explained solely by the density or properties of the peripheral thermal receptors and thus must reflect processing mechanisms in the central nervous system.

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Sorbitol enhances the physicochemical stability of B12 vitamers

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000578 ◽

2020 ◽

Vol 90 (5-6) ◽

pp. 439-447 ◽

Cited By ~ 1

Author(s):

Andrew Hadinata Lie ◽

Maria V Chandra-Hioe ◽

Jayashree Arcot

Keyword(s):

Ascorbic Acid ◽

Uv Light ◽

Heat Exposure ◽

Water Soluble ◽

Uv Exposure ◽

Physicochemical Stability ◽

Before And After ◽

The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

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Effect of prolactin inhibition under heat exposure on water intake and excretion of urine, sodium and potassium in bulls

Acta Endocrinologica ◽

10.1530/acta.0.0940315 ◽

1980 ◽

Vol 94 (3) ◽

pp. 315-320 ◽

Cited By ~ 8

Author(s):

D. Schams ◽

E. Stephan ◽

R. D. Hooley

Keyword(s):

Water Intake ◽

Heat Exposure ◽

Physiological Role ◽

Treated Group ◽

Serum Prolactin ◽

Control Value ◽

Light Regimen ◽

Group I ◽

Urinary Potassium ◽

Group Ii

Abstract. Six Holstein bulls were housed in a climate-chamber under constant light regimen and after two weeks of preconditioning at 15°C, 60% relative humidity RH (day) and 12°C, 60% RH (night) were subjected to two weeks of heat exposure. This involved one week at 30°C and 60% RH (day) and 25°C and 60% RH (night) and a further week at 35°C, 60% RH (day) and 30°C, 60% RH (night). Three bulls were untreated (group I) and 3 bulls were treated (group II) just before and during heat exposure with a prolactin inhibitor to study the possible physiological role of prolactin on the regulation of water, potassium and sodium. Serum prolactin levels increased significantly (P < 0.01) in group I from the control value of 6 ng/ml to 33 and 44 ng/ml when the ambient temperature was increased (weeks 3 and 4) and then decreased to 21 and 12 ng/ml after reduction in temperature during weeks 5 and 6, respectively. For group II prolactin values decreased under the treatment with the prolactin inhibitor to 0.5 ng/ml and remained at this level throughout the experiment. GH levels were unaffected by heat treatment or by treatment with prolactin inhibitor. There were no differences between groups I and II in respiratory rate, pulse rate and rectal temperature. Water intake increased in both groups under heat exposure but decreased significantly afterwards only in group II. Differences in urinary excretion volume and blood serum osmolality were not significant. Urinary potassium and sodium excretion were unchanged in group II but increased with heat exposure in group I. During heat exposure 2 bulls of group II lost weight despite maintaining food intake.

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The influence of repeated sprints over the aerobic performance at swimmers

10.15405/epsbs.2018.03.25 ◽

2018 ◽

Author(s):

Jari Sabri

Keyword(s):

Aerobic Performance ◽

Repeated Sprints

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A Practical Ultrasonic Inspection Method for Detecting and Characterising Defects Found Within Composite Repairs

10.24868/issn.2515-818x.2018.013 ◽

2018 ◽

Author(s):

J Downing ◽

A Hook

Keyword(s):

Wall Thickness ◽

Steel Substrate ◽

Ultrasonic Method ◽

Ultrasonic Inspection ◽

Heat Exposure ◽

Matrix Cracking ◽

Ultrasonic Technique ◽

Inspection Method ◽

Composite Repairs ◽

Layered Matrix

Two steel substrate test panels were developed to represent common plate thicknesses found on naval vessels and scanned using the Babcock developed ultrasonic technique. One sample comprised of a series of slotted surface breaking flaws of varying widths and through thicknesses to represent fracturing/cracking. The inspection method detected simulated cracking to a depth of 2mm and 0.5mm in width. The second sample included numerous loss of wall thickness areas of varying diameters and through thicknesses, with the smallest detectable loss of wall thickness being 0.1mm at a 15mm diameter. After proving confidence in detection, there was a need to characterise flaws to provide support and ascertain a repair action. Samples were produced that were subjected to either impact or heat exposure to induce realistic representative damage. The practical ultrasonic method was successfully used to independently characterise between the samples, with induced de-laminations caused by blisters, and multi layered matrix cracking caused by varying levels of projectile impacts, due to their unique morphology.

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