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1
Martin, David E. „The effect of heat stress on excess post exercise oxygen consumption“. Virtual Press, 1992. http://liblink.bsu.edu/uhtbin/catkey/834623.
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While a great deal of research has been directed towards the phenomena of excess post exercise oxygen consumption (EPOC), the effect of thermal stress on EPOC is not well defined. To assess the effect of heat stress on EPOC, seven healthy, active subjects (4 female, 3 male; 23.9 ± 2.0 years of age) performed 4 trials: one control (quiet rest) and one exercise (45 minutes of cycling at 65% VO2max workload) trial in moderate (23° C, 50% humidity) and hot (35° C, 50% humidity) environments. Oxygen consumption (V02), heart rate (HR) and rectal temperature (RT) were assessed pre, during and post control or exercise. Subjects were monitored until post exercise VO2 had returned to within ±2% of baseline. EPOC was determined by subtracting baseline VO2 from total V02 during the post exercise period. During the first 15 minutes (acute) post exercise, a significant EPOC (p = 0.0019) was seen in both exercise conditions over both control conditions. During the slow phase (> 15 minutes post exercise to baseline), there was no significant difference between the hot control (HC), moderate exercise (ME), or hot exercise (HE) EPOC. Total time post exercise until baseline was achieved was 35, 44, and 51 minutes for HC, ME, and HE respectively. HR was significantly elevated in both exercise conditions. During the acute post exercise period, HR in HE was elevated above MC, ME and HC (p < 0.05). RT was elevated in both exercise conditions during and post exercise. The present data indicate that heat stress does not have a significant effect on the magnitude or duration of EPOC.School of Physical Education
2
Houmard, Joseph A. „Rate of heat acclimation : effects of exercise intensity and duration“. Virtual Press, 1988. http://liblink.bsu.edu/uhtbin/catkey/533882.
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Hogan, Kyla B. „The hemostatic responses to exercise in hot and cold temperatures“. Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1398717.
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Purpose: The impact of temperature on the coagulative response to exercise has not been well described. The purpose of this study was to assess the response of plasma thrombin-antithrombin (TAT) to exercise during exposure to both hot and cold temperatures, and to compare those responses to exercise under normal, temperate conditions. Methods: Fifteen healthy male subjects (25.3 + 4.3 years) volunteered to participate in this study. Subjects completed maximal cycle ergometer exercise tests in three different temperatures (20°C, 5° or 8° C, and 30°C) in an environmental chamber. All tests were conducted in random order and separated by at least seven days. Blood samples were obtained before and immediately after exercise and analyzed by Elisa to determine plasma concentrations of thrombin-antithrombin complex (TAT). Results: Subjects demonstrated significantly elevated plasma levels of TAT in all three temperatures immediately after exercise (normal =1.04 ± 0.44 ng/ml, cold =1.34 ± 0.79 ng/ml, hot =1.18 + 0.95 ng/ml) when compared to baseline measures (normal = 0.45 ± 0.26 ng/ml, cold = 0.88 + 0.57 ng/ml, hot = 0.64 + g/ml). Subjects also showed significant elevations in TAT concentrations both before and after exercise in the cold temperature when compared with the normal temperature. There was no significant difference between the hot and normal temperatures. Conclusion: An individual's coagulation potential is increased following maximal physical exertion and may be further increased by exposure to colder temperature. Key Words: coagulation, physical exertion, temperature, thrombosis.School of Physical Education, Sport, and Exercise Science
4
Davis, Jacqueline A. „The hypertensive response to repeated days of heat-exercise exposure“. Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/562777.
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The physiological responses of hypertensive subjects to a single bout of exercise in a hot environment have been investigated. It was the purpose of this study to compare the effect of successive days of exercise in the heat on borderline hypertensive and normotensive individuals, with particular interest being paid to the positive relationship that exists between plasma volume and blood pressure. Eight hypertensive subjects (HT) and 8 normotensive controls (NT) performed a standardized work task, (walking for 60 minutes at 3.5 mph on a 5% grade), in dry heat, (40C, 257. RH), on 7 successive days. Working capacity and acclimatization were compared during two, 90 minute heat tolerance tests (HTT), one prior to, and the other following the acclimation period.Both groups demonstrated a similar degree of heat acclimation, as reflected in significantly lower HTT2 core temperatures, (P< 0.05), and heart rates, (p< 0.01). Plasma volume expansion over the 9 days was also equal for both groups (+77.), but appeared to have no effect on their resting or exercising blood pressures. No differences were observed in the ability of either group to complete the work task, although the HT group exercised at a significantly higher percentage of their maximal oxygen uptake, (p< 0.05), than the NTs.These results indicate that no abbreviation in working capacity is experienced by borderline HT'% during exercise in the heat as a consequence of their high blood pressure. The anticipated elevation in blood pressure as a result of an expansion i n plasma volume did not occur. Consequently, these individuals show the same positive acclimation to exercise in the heat as their NT counterparts.School of Physical Education
5
Kerr, Chadwick G. „Hypothermia during Olympic triathlon : influence of body heat storage during the swimming stage“. Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1014852.
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The purpose of this study was to determine if mild heat stress induced by wearing a wet suit while swimming in relatively warm water (25.4 ± 0.1°C) increases the risk of heat injury during the subsequent cycling and running stages. Specificlly, during an Olympic distance triathlon in a hot and humid environment (32°C & 65% RH). Five male triathletes randomly completed two simulated triathlons (Swim=30 min; Bike=40 km; Run=10 km) in the laboratory using a swimming flume, cycle ergometer, and running treadmill. In both trials, all conditions were identical, except for the swimming portion in which a full length, sleeveless neoprene wet suit was worn during one trial (WS) and a competitive brief swimming suit during the other (SS). The swim portion consisted of a 30 min standardized swim in which oxygen consumption (V02) was replicated, regardless of WS or SS. During the cycling and running stages, however, the subjects were asked to complete the distances as fast as possible. Core Temperature (T) was not significantly different between the SS and WS trials at any time point during the triathlon. However, mean skin temperature (TSk) and mean body temperature (Tb) were higher (p<0.05) in the WS at 15 (TSk=+4.1°C, Tb=+1.5°C) and 30 min (TSk=+4°C, Tb=+1.6°C) of the swim. These TSk and Tb differences were eliminated by 15 min of the cycling stage and remained similar (p>0.05) through the end of the triathlon. Moreover, there were no differences (p>0.05) in V02, heart rate (HR), rating of perceived exertion (RPE), or thermal sensation (TS) between the WS and SS. Additionally, no significant differences were found in cycling (SS=1:14:46 ± 2:48 vs. WS=1:14:37 ± 2:54 min), running (SS=55:40 ± 1:49 vs. WS=57:20 ± 4:00 min) or total triathlon times (SS=2:40:26 ± 1:58 vs. WS=2:41:57 ± 1:37 min). Therefore, the primary finding was that wearing a wet suit during the swimming stage of an Olympic distance triathlon in 25.4°C water does not adversely affect the thermal responses or the triathlete's ability to perform on the subsequent cycling and running stages.School of Physical Education
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Arjona, Anibal Augusto. „Molecular responses of neonatally heat stressed broilers exposed to acute heat stress“. Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39965.
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Exposure of broiler cockerels to between 35.0 to 37.8 C for 24 hr at 5 days of age increases their survival when exposed to a heat challenge at 6 weeks of age (35.0-37.8 C; RH 50% ). This' phenomenon does not resemble acclimation since the physiological changes known to occur in acclimated birds exposed to heat have not been observed in the neonatally stressed birds. A series of experiments were conducted to elucidate the mechanisms of neonatally induced thermotolerance. In Experiment 1, the erythrocyte protein profile of control and 5 days heated birds prior to and during exposure to acute heat were determined. Prior to juvenile heat exposure no differences in the erythrocytic protein profile of neonatally stressed and control birds were observed at any age (10, 17, 24, 31 and 38 days of age) when maintained under control conditions. However, upon exposure to an acute heat challenge (40.5 C; 52 days of age) temporal and differential expressions of proteins similar in molecular weight to heat shock proteins (HSPs) were observed between the neonatally stressed and control birds. In Experiment 2, the effects of neonatal heat stress at various ages (5, 8, 12, 16 days of age) on the protein synthesis profile of heart, brain (telencephalon, diencephalon, brain stem, cerebellum) and liver tissues during exposure to an acute heat challenge were studied. In addition, body temperature during neonatal heat exposure was monitored. A significant increase in body temperature was observed during neonatal heat stress. A steady increase in the magnitude of the temperature change was noticed up to 12 days of age. Body temperature of birds exposed to neonatal heat at 16 days of age was similar to that of birds heated at 5 days of age.Ph. D.
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Heyns, Gerhardus Johannes. „Influence of macro- versus microcooling on the physiological and psychological performance of the human operator“. Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1016247.
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This study evaluated the effect of a macro- versus a microcooling system on the cognitive, psychomotor and physiological performance of human operators. Male subjects (n = 24) were acclimatized for four days and then subjected to three different environmental conditions: hot ambient (40°C; 40% RH), microcooling and macrocooling. Each environmental condition was repeated twice; once under a rest condition and once while simulating a physical workload of 40 W. Four performance tests (reasoning, eye-hand coordination, memory, reaction time) were conducted once every hour for four hours. Five physiological measurements, viz rectal temperature, skin temperature, heart rate, total sweat loss and sweat rate, were taken. A significant difference existed between the physiological responses under the hot ambient condition and both cooling conditions. For all five physiological parameters he human operator benefitted substantially whatever the cooling condition. The psychological performance results indicated a greater benefit under the cooling conditions, though various external factors may have influenced responses. User perception showed that macrocooling was perceived to be the optimal method of cooling. The results showed that there was no difference in the extent to which both rectal temperature and heart rate (for rest and work conditions) decreased over the 4-hour study period with micro- and macrocooling. In the baseline hot environment both increase. Sweat rate was lowest when resting or working in a microcooled environment and at its highest in the hot baseline environment. Mean skin temperature was lowest (for rest and work conditions) with microcooling and highest in the hot baseline environment. Reaction time and memory/attention were the same under all three environmental conditions. Eye-hand coordination was better with cooling than without, but did not differ between the two cooling conditions. Reasoning ability was poorest under the hot baseline condition and best in the macrocooled environment. User perception showed that the subjects found macrocooling highly acceptable. Microcooling was found to be uncomfortable, particularly because cold air (18 - 21°C) entered the jacket at one point which caused numbness of the skin at that point. Jackets did not always fit subjects well and the umbilical cord restricted free movement.
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WIDELITZ, RANDALL BRUCE. „HEAT SHOCK PROTEIN SYNTHESIS AND THERMOTOLERANCE EXPRESSION IN RAT EMBRYONIC FIBROBLASTS (HYPERTHERMIA, GENE REGULATION)“. Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183851.
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In response to a variety of hyperthermic treatments, rat embryonic fibroblasts synthesize heat shock proteins (hsps), including those with molecular weights of 68,000 (hsp 68), 70,000 (hsp 70) and 89,000 (hsp 89). Hyperthermic stresses, which produce the hsps, also cause expression of thermotolerance. The dependence of thermotolerance expression on hsp synthesis was investigated in this mammalian cell line under different heating conditions. Temperature shift experiments showed that hsp synthesis and thermotolerance expression were dependent not only on the absolute hyperthermic temperature, but also on the difference between the initial incubation temperature and the hyperthermic temperature. Small temperature differences which produced no cell killing did not cause detectable synthesis of hsp 68. Increasing the difference of the initial and hyperthermic temperatures reduced cell survival and increased the synthesis of hsp 68. Thermotolerance could be expressed by surviving cells following an initial heat stress even when both heat shock and general protein synthesis were inhibited. Cells exposed to cycloheximide were heated, incubated at their initial temperature for six hours and reheated in the presence of the drug. The inhibitor was then removed and the cells plated for colony formation. The hsps were expressed during this latter incubation period. The regulation of hsp 70 in rat fibroblasts was investigated next. Hsp 70 synthesis rates correlated with the amount of hsp 70 encoding mRNA. The time course of heat shock synthesis and general protein synthesis recovery were each dependent on the duration of the heat stress. Inhibiting protein synthesis with cycloheximide resulted initially in the accumulation of the RNA encoding hsp 70 but did not effect the normal turnover of this RNA species. The conclusions based on these findings are that thermal survival adaptation can be expressed in the absence of hsp 68 synthesis. Hsp 68 is expressed by cells that will ultimately die (see Chapter 2). The hsps do not appear to protect cells against subsequent heat stress. They may function in a repair capacity (see Chapter 3). Hsp 70 expression is primarily regulated by transcription in Rat-1 cells. Hsp 70 does not act to regulate its own turnover (see Chapter 4).
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Martin, Andrew. „Measurement of heat strain in firefighters“. Thesis, Queensland University of Technology, 1990. https://eprints.qut.edu.au/35956/1/35956_Martin_1990.pdf.
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A comparative study of six different fire-fighting clothing ensembles to determine the heat stress
imposed on the wearer was conducted. Physiological indicators of heat strain were monitored while
subjects performed set tasks for up to 30 minutes in controlled environments. The differences between
ensembles was considered. For each ensemble, six subjects performed set tasks in two controlled environments for 30 minutes or until one of a set of termination criteria was met. In the first environment subjects stepped at a set rate
in 40°C dry bulb and 60% humidity conditions. A number of weights, pre-determined to work the subject
at a set level of the individual's Heart Rate Increase Capacity, were carried. In the second environment
subjects lifted bricks at a set rate in front of two 1500 W radiators in 30°C and 60% conditions. Dry bulb
temperature, Wet Bulb Globe Temperature, and humidity were monitored to ensure consistency of test
conditions. A control test with light clothing was performed before the suit testing. Subjects were partially acclimatised prior to testing. Physiological indicators of strain (mean skin temperature, heart rate, blood pressure, and body fluid loss) were monitored and differences between ensembles considered. Skin temperature was calculated from a weighted average of measurements at 6 sites (chest, back, cheek, thigh, calf, and upper arm). Thermocouples (#32 gauge T-type) were attached to the skin with Leukoplast adhesive tape and the temperatures were recorded using a Fluke digital thermometer (sensitivity of 0.1°C) after every minute
of work.
Heart rate was stored every 15 seconds with one monitor and a backup monitor stored the rate at
every heart beat. Body fluid loss and amount of fluid absorbed by the clothing were found by weighing
nude subjects and clothing before and after testing. Scales accurate to 1 O g were used. Final systolic
and diastolic blood pressures were compared to resting values using an automatic monitor. Perceived views of the subjects were also obtained using a questionnaire.
Heart rate showed a steady cyclic increase during each test. Skin temperature rose in the hot environment and partially recovered in the moderate environment also producing a cyclic increase. The subjects lost from 600 g to 1200 g of fluid in each test. Systolic B.P. consistently increased and diastolic B.P. on average decreased. The ranks of the suits obtained were similar for all the measured parameters and the questionnaire. Skin temperature and heart rate clearly showed differences between the ensembles.
10
Williams, Winifred Elizabeth. „HEAT TRANSFER IN THE MICROCIRCULATION“. Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275277.
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Lambert, Charles Paul. „Fluid replacement after exercise in the heat : influence of beverage carbonation and carbohydrate content“. Virtual Press, 1990. http://liblink.bsu.edu/uhtbin/catkey/722187.
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This investigation evaluated the Influence of beverage carbonation and carbohydrate content on fluid replacement following exercise/thermal dehydration. Eight recreationally trained men cycled at 50% of their maximal aerobic power in a hot environment (40°C 40% relative humidity) until a body weight loss of 4.12 ± 0.02% was attained. In the subsequent four hours subjects ingested one of four randomly assigned solutions at 15 minute intervals. The total volume ingested equalled that lost during dehydration. The solutions varied in their carbohydrate and carbonation content as follows: 1) CK: carbonated 10% carbohydrate solution, 2) NCK: non-carbonated 10% carbohydrate solution, 3) CNK: carbonated non-caloric solution, and 4) NCNK: non-carbonated non-caloric solution. Before dehydration and at 0, 60, 120, 180, and 240 minutes of recovery subjects performed a five minute cycling bout (SCB) at 70% venous blood samples were obtained before and after dehydration, and at 30, 90, 150, and 240 minutes of of their maximal aerobic power. In addition, resting data from the carbohydrate treatments were pooled and recovery. Rehydration evaluated from body weight, plasma volume, plasma protein, and urine volume data was not significantly (p> 0.05) different between treatments at any time. In addition, carbonated beverage (CK and CNK) ingestion did not significantly alter the pC02 or pH of venous blood at rest or the respiratory exchange ratio (RER) during exercise, however, the ingestion of carbohydrate beverages (CK and NCK) elevated the RER during the SCB relative to the level elicited by Ingestion of non-carbohydrate beverages. Oxygen consumption during the SCB at 240 minutes was significantly (p< 0.05) higher in the non-carbohydrate treatments (NCNK vs. CK and CNK and NCNK vs. NCK), however, no differences in caloric expenditure were observed. Arterialized blood lactate one minute after each SCB was not different between treatments. Lactate levels were significantly higher, however, when compared to the non-carbohydrate treatments. No significant differences were observed in ratings of perceived exertion, or ratings of gastrointestinal comfort. The results of this Investigation suggest that solutions which are carbonated and/or contain a carbohydrate concentration of 10 b are as effective as non-carbonated and/or non-carbohydrate solutions with regard to fluid replacement. In addition, the ingestion of carbonated beverages does not appear to be associated with alterations in the pC02 or pH of venous blood or gastric distress relative to the levels attained with non-carbonated beverages.School of Physical Education
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Morrison, Shawnda A., und n/a. „Causes and effects of cardiovascular strain in the heat“. University of Otago. School of Physical Education, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080404.162058.
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Passive and active heat loading causes cardiovascular strain, which can have diverse and substantial effects. Thus, cardiovascular function is integral to work and heat stress tolerance, but recent hyperthermia and exercise literature has not emphasised this relationship, instead focusing on the roles of upper �critical� core temperature or rate of heat storage as primary mechanisms of fatigue. Therefore, the aim of this thesis was to examine some potential causes and effects of cardiovascular strain under heat stress, including potential strategies for attenuating that strain.
Body precooling before exercise increases heat storage capacity; the primary mechanism by which attenuations in thermal and cardiovascular strain, and improved work capacity is thought to occur. However, no precooling study has utilised realistic airflow in the laboratory, possibly inflating its purported benefits. Therefore, Study One examined the cardiovascular, thermal, psychophysical and ergogenic effects of precooling with and without airflow in the heat (30�C, 50% rh). Ten males completed four trials in balanced order, comprising 60- min immersion in thermoneutral (35�C) or cool (24�C) water before cycling at 95% ventilatory threshold with airflow (~4.8 m�s⁻�) or no airflow, until exhaustion. Heart rate and mean core, body, and skin temperatures were attenuated for 15 min into cycling after precooling. Endurance time was extended by 30 � 23 min with airflow, and 16 � 15 min with precooling relative to control (28 � 12 min) but not further extended with strategies combined (29 � 21 min). Precooling removed 784 � 223 kJ�m⁻� (calorimetrically); less than the effect of airflow alone (1323 � 1128 kJ�m⁻�).
Competition for blood between tissues is pronounced during exercise in the heat: skin and gut have marked increases and decreases, respectively. Gut ischemia affects epithelial tight junction integrity, allowing lippopolysaccharide ingress and immune responses. Bovine colostrum may attenuate gut permeability. Study Two (double-blind, placebo controlled) investigated the effects of aerobic fitness (7 highly fit, 8 moderately fit) and bovine colostrum on physiological and perceived strain, and performance during mixed-mode exercise; cycle 15 min at 50% maximal heart rate range (HRR), run 30 min at 80% HRR then 30 min self-selected paced before another 15 min cycle at the same work-rate. Airflow was graded to running speed. During the last cycle, blood pressure, stroke volume and total peripheral resistance were lower, heart rate and skin blood flow increased, and skin temperature was unchanged compared to the first cycle. Indices of fever response (IL-1β, TNF-α) were not evident during exercise, nor were those of blood-brain barrier permeability (S100β) or cognitive impairment (Stroop test). Neither bovine colostrum, nor higher fitness modified these measures.
Moving to upright posture is orthostatically stressful and can initially decrease cerebral perfusion. Compression garments are used to assist venous return; while their effectiveness is unknown, they could reduce heat or orthostatic-induced hypoperfusion. Study Three investigated the cardiovascular and cerebrovascular responses to orthostatic stress with and without passive heating (+0.5�C). Fifteen participants completed two trials (compression v placebo garments) in balanced order. Cerebral autoregulation was assessed via 3-min stand, and via thigh cuff inflation. All participants experienced initial orthostatic hypotension upon standing in one or more trials, with 4/15 individuals experiencing presyncopal symptoms, aborting the standing protocol. In those who "fainted", reductions in blood pressure and partial pressure of end-tidal CO₂ reduced middle cerebral artery velocity. Neither training status nor compression trousers modified the responses.
Collectively, cardiovascular strain to heat stress is attenuated when realistic airflow is provided. Increased cardiovascular strain does not inevitably result in clinical outcomes to heat stress. Higher fitness does not necessarily attenuate cardiovascular responses or higher tolerance to heat stress.
13
Bolster, Douglas R. „The effects of precooling on thermoregulation during subsequent exercise in the heat“. Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1041903.
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The purpose of this study was to lower body core temperature prior to a simulated portion of a triathlon (swim-15min; bike-45min) and examine whether precooling could attenuate thermal strain and increase subjective exercise tolerance in the heat. Six endurance trained triathletes (mean ± SE, 28 ± 2 yr, 8.2 ± 1.7 % body fat) completed two randomly-assigned trials, one week apart. The precooling trial (PC) involved lowering body core temperature (-0.5°C) in water prior to swimming and cycling. The control trial (CON) was identical except no precooling was performed. Water temperature and environmental conditions were maintained at -25.6°C and -26.6°C/60% RH respectively, throughout all testing. Mean time to precool was 31:37 ± 8:03 and average time to reach baseline temperature during cycling was 9:35 ± 7:60. Oxygen consumption (VO2), heart rate (HR), rate of perceived exertion (RPE), thermal sensation (TS), and skin (Tsk) and core (Ta) temperatures were recorded following the swim segment and throughout cycling. No significant differences in mean body (TO or Tsk were noted between PC and CON, but a significant difference (P<0.05) in T, between treatments was noted through the early phases of cycling. No significant differences were reported in HR, V02, RPE, TS or sweat rate (SR) between treatments. Body heat storage (S) was negative following swimming in both PC (92 ± 6 W/m2) and CON (66 ± 9 W/m2). A greater increase in S occurred in PC (109 ± 6 W/m2) vs. CON (79 ±4 W/m2) during cycling (P<0.05) . Precooling attenuated the rise in T,, but this effect was transient. Based on the results from this study, precooling is not recommended prior to endurance exercise in the heat.School of Physical Education
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Alm, David Michael. „Comparison and interaction of heat and salt stress in cultured tobacco cells“. Virtual Press, 1986. http://liblink.bsu.edu/uhtbin/catkey/445616.
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Cultured tobacco cells (Nicotiana tabacum L., cv Wisconsin-38) were subjected to temporary sub-lethal heat and salt shock treatments to determine the effects of these treatments on various physiological parameters after subsequent lethal heat or salt stresses. Tobacco cells developed a tolerance to a non-permissive temperature stress (54C for 14 min) when pretreated with heat shock of 38C for 2h but not when pretreated at 42C for 2h. Cells pretreated at 38 (2h) exhibited less than 30% normal growth when the 54C stress came immediately after the 38C treatment. Tolerance to the 54C stress developed with increased interval between shock and stress with cells exhibiting 95% normal regrowth when the 54C stress was administered 8h after the 38C shock. The developement of heat tolerance was inhibited if heat shock was done in the presence of a non-injuring level of EGTA (.0.5mM). Cells treated with EGTA during heat shock grew normally at 23C but not after a 54C heat stress. EDTA (0.5mM) had little effect on the acquisition of tolerance to heat stress.Wisconsin-38 cells developed a tolerance to a non-permissive salt stress (2% NaCl for 16h) when pretreated at a lower salt level (1.2% NaCl) for 3h. Cells heat shocked at 38C exhibited increased tolerance of the lethal salt stress up to 8h. Conversely, cells heat shocked at 42C exhibited immediate tolerance to lethal salt stress and this tolerance decayed over eight hours. The heat shock-induced acquisition of salt tolerance was inhibited by both EGTA and EDTA.Proteins synthesized during heat and salt stress treatments were labeled with [35S]-methionine and/or [3H]-leucine and separated using Sodium dodecylsulfate polyacrylamide gel electrophoresis. Fluorographic analysis of the gels indicate that a number of proteins are produced in response to heat shock. Similar analysis of proteins from salt shocked cells indicates that no salt shock proteins are produced in response to a brief low-level sodium chloride shock.
15
Chen, Zong-Ping. „Three-dimensional hyperthermia cancer treatment simulation“. Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184852.
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A simulation program to study the three dimensional temperature distributions produced by hyperthermia in anatomically realistic inhomogeneous tissue models has been developed. The anatomical data for the inhomogeneous tissues of the human body are entered on a digitizing tablet from serial CT scans. The program not only predicts temperature distributions in regions dominated by blood perfusion (with large number of small capillaries), but it can also predict the temperatures inside of and at the vicinity of large blood vessels. The program can be used for different power deposition patterns from various heating modalities, but they must be calculated independently. In this study, the author's attention has been focused on ferromagnetic implants. The program has been used to comparatively evaluate two and three dimensional simulations in a series of parametric calculations based on simple tissue models for both uniform power deposition and ferromagnetic implants. The conclusions drawn from these studies are that two dimensional simulations can lead to significant errors in many situations, and therefore three dimensional simulations will be necessary for accurate patient treatment planning. The conclusion from the geometrically simple model is substantiated by the results obtained using the full 3D model for actual patient anatomical simulations. The program has also been used for several parametric studies. The effect of the thermal conductivity used in the models on the temperature field has been studied, and the results show that its value in the range of 0.4 to 0.6 W/m/°C (valid for most soft tissues) has only a slight effect on the resultant temperature fields. The heating ability of the ferromagnetic implants has also been investigated for different blood perfusions. The effects of the Curie point of the ferromagnetic seeds, and seed spacing are also studied. Finally, the impact of large blood vessels on the resultant temperatures are studied, and the results show that the effect is dramatic and therefore it must be included in the simulations in order to predict accurate temperature fields. Finally, the program has been used to analyze a previously performed dog experiment, and a previously performed clinical treatment. A comparison between the predicted temperatures and the measured ones show that good agreement has been achieved for the clinical treatment, but not for the dog experiment. These results are studied in detail, and the conditions under which this program can be used as a hyperthermia patient treatment planning tool is discussed.
16
Johnsen, Suzanne Louise 1960. „Early embryos of dams of heat stress“. Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277034.
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Increased environmental heat causes early embryonic death before implantation. This study was designed to examine tissues of dams exposed to environmental temperatures of 36°C and to examine 72 hour old embryos from these dams. Results showed adult mice exposed to heat stress had significant changes in liver morphology with hepatocyte swelling and vacuolization of the cytoplasm, organelles in the hepatocytes were displaced next to the cell membrane. After 48 hours of recovery from heat stress, liver morphology appeared normal. Embryos from heat stressed dams had delayed development indicated by increased 2alpha helical cellular inclusions. Embryos responded differently to different fixation techniques indicated permeability changes in either the zona pellucida or cellular membranes. Litter size or pup survivability from heat stressed dams allowed to recover indicated changes seen at this point were reversible
17
Wall, Bradley A. „Effect of exercise-induced hypohydration on body temperature and cycling time trial performance in the heat with adequate facing wind speed“. Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/167.
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"Background: Laboratory studies have shown during prolonged exercise that 2-3% dehydration can lead to greater increases of body temperature and cardiovascular work, altered metabolic function, and impaired exercise performance, compared to when no fluid deficit occurs. However, previous studies were conducted in relatively windless environments (i.e. wind speeds
18
Peiffer, Jeremiah J. „Short term recovery with cold water immersion following cycling in the heat“. Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/209.
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Increases in core temperature are associated with perceptions of fatigue and reductions in physical work capacity. Following completion of a bout of exercise in the heat, cold water immersion (CWI) is sometimes used by athletes to rapidly decrease their core temperature, and may facilitate recovery. Few studies however, have examined the effects of CWI after exercise in the heat on short term recovery. In addition, whether or not performance benefits can arise from this recovery modality is equivocal. This thesis incorporates four individual studies surrounding the area of CWI recovery and one study that ,examined the reliability of a measure used to estimate blood flow. All of these studies have been published or submitted to refereed sport science journals.
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Ott-Reeves, Ellen (Ellen Theresa). „In Situ Hybridization of 70 kD Heat Shock Protein mRNA in a Rat Model of Ethanol Self-Administration“. Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc332564/.
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Sucrose fading was used to initiate self-administration of ethanol on an FR4 schedule in male Fischer 344 rats. Rats showed low response rates for ethanol alone. After administration of liquid diet containing ethanol, ethanol intake increased over levels prior to administration of the liquid diet. In situ hybridization compared mRNA for the inducible or constitutive 70 kD heat shock proteins in ethanol and nonethanol rats. Both inducible and constitutive mRNAs were found in nonethanol and ethanol tissues. In peripheral organs, radiolableling was higher in ethanol tissue. In brain regions, nonethanol tissues showed higher radiolabeling.
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Hobbs, Forrest Craig. „The effects of neonatal/juvenile heat stress and varying L- tryptophan levels on growth parameters, meat quality, and brain neurotransmitter levels in turkeys“. Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/46040.
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A 2 x 2 x 4 factorial experiment utilizing 640 male Large White turkeys was conducted to determine the effects of neonatal/juvenile heat stress and tryptophan supplementation upon growth to 129 days of age, as well as meat quality and brain neurotransmitter levels. Treatments consisted of neonatal heat stress (36 continuous hours at 38 C) starting at 5 days of age, juvenile heat stress (8 hours a day at 38 C for 5 consecutive days) starting at 106 days of age, and tryptophan supplementation (0, .1, .2, and .3 % added to the diet) from 112 days of age to market (129 or 138 days of age). Feed consumption, weight gain, and mortality were l recorded and selected meat quality measurements and brain neurotransmitter levels were determined. Weight gain and feed consumption were significantly reduced by juvenile heat stress treatment while early stress, late stress (EL) treatment significantly increased mortality as compared to CC treatment during this period. Such findings revealed that neonatal heat stress did not reduce losses due to heat stress at market age. After live haul, (129 days of age), EC birds had significantly greater cooking loss as compared to birds of the other three treatments and CC birds had significantly larger thigh weights than EL treated birds. In birds analyzed at 138 days of age, CL treatment resulted in a significantly higher Hunter L-value (lightness) in pectoralis major tissue as compared to CC treatment, indicating a darkening of pectoralis musculature due to juvenile heat stress treatment. Tryptophan supplementation resulted in no significant differences in food intake, body weight, or body weight gain. Serotonin, 5 hydroxyindole acetic acid (5-HIAA), and norepinephrine levels increased linearly with dietary tryptophan supplementation in the four brain regions analyzed while linear increases in L-dihydroxyphenylalanine (L·DOPA) occurred in all regions analyzed except for the cerebellum due to Lâ tryptophan supplementation. Plasma levels of serotonin also increased in a positive dose-response fashion while tryptophan supplementation at all levels significantly reduced norepinephrine levels as compared to the basal diet. The addition of .1% tryptophan to the tinisher diet significantly increased carcass weight and thigh weights while no significant differences occurred in breast protein and ether extract, or in either pectoralis major and biceps femoris shear or Hunter color values due to supplemental tryptophan.
Master of Science
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Hayamanesh, Shahnoosh. „The effect of high temperature on physiological and metabolic parameters and reproductive tissues of okra (Abelmoschus esculentus (L.) Moench)“. Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18097.
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Okra is an important summer vegetable crop and high temperature has been shown to lower its growth and yield. In this study, 119 okra genotypes were initially screened for their response to a short period of heat shock (45°C for 4h and 6h) in a controlled environment facility by assessing chlorophyll fluorescence (Fv/Fm and Fv’/Fm’), photosynthesis (A), stomatal conductance (gs) and electrolyte leakage (EL) in control and heat. Additionally, DNA of fresh green leaf of okra was isolated by a modified CTAB method with additional PVP and RNase and amplified by 8 polymorphic SSR markers to generate a dendrogram. This preliminary screening identified 8 polymorphic genotypes with less than 50% genetic similarity, reduced Fv’/Fm’ in the heat with varying responses in gs, A and EL. These 8 genotypes were studied for their response in a long-term heat stress environment in two adjacent plastic tunnel houses, with 10°C warmer average temperatures in the hot tunnel house. After 15 weeks, high temperature had no significant effect on Fv’/Fm’ and A, while gs and EL increased significantly and yield decreased due to significant reduction in pollen germination. The tunnel house experiment was repeated (with 4 genotypes) assessing physiological, biochemical and histological parameters at flowering and bud initiation stages and monitored every 2 weeks for a total of 6 weeks. Okra demonstrated a physiological acclimation response however yield decreased severely due to heat damage in reproductive tissue. In the heat, plants produced lower anther numbers and pollen germination. The shape and structure of male tissues was altered in the early stage of bud development which may have resulted from alteration in carbohydrate content in the leaves. The results of this study suggest that okra is more vulnerable in the early stages of growth and development.
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Al-Abry, Ghaita Suleiman Nasser. „The effect of transportation and heat as stress factors on some physiological aspects of Omani goats“. Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546463.
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Iyasere, Oluwaseun Serah. „Effect of heat and physiological stress on the growth performance, physiology and welfare of broiler chickens“. Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2585.
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Broilers can be faced with a several stressful conditions during their production cycle which can have implications for both growth performance and animal welfare. Animal welfare encompasses the physical and mental well-being of animals, assessed from the biological functioning and subjective experience. The aims of this thesis were i) to develop and validate non-invasive means of assessing the welfare of broilers under physiological and episodic heat stress conditions, ii) to investigate the impact of episodic heat stress, physiological stress and light wavelength on the growth performance, physiology and welfare of broiler chickens and, finally, iii) to investigate a novel means of alleviating heat stress in broilers. Endogenous corticosterone measured in the urate sphere was suppressed by dexamethasone administration. In a cognitive bias task, birds offered mealworms injected with corticosterone to mimic chronic stress were pessimistic in their judgement about ambiguous positions. A positive correlation was established between physiological indicators of stress and cognitive bias. Although light wavelength was confounded with light intensity in our study, there was no difference in growth performance and cognitive ability of birds reared in the blue and red light, except for increased activity of birds in red light. Under simulated episodic heat stress, the change in CBT measured from a temperature-ID chip (ΔCBT-chip) and a data logger (ΔCBT-logger) was positively correlated. Significant positive correlations were found between the change in surface body temperature (SBT) under wing (ΔWT) and ΔCBT-chip, and between ΔWT and ΔCBT-logger. Significant positive regression equations relating change in CBT and RR with apparent equivalent temperature (a factor which combines environmental temperature and RH) were also developed. High temperature coupled with high RH aggravated the respiratory rate (RR) of broilers and this was accompanied by suppression of peening behaviour. High heat stress for 3 hours had a greater impact on birds than moderate heat stress for 6 hours. For broilers exposed to moderate heat stress, the provision of additional cup drinkers reduced the rise in CBT and the proportion of time spent in wing drooping behaviour, but enhanced SBTs suggesting increased heat dissipation.
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Venable, Adam Steven. „Women Have Higher Skin Temperature on the Back during Treadmill Exercise in a Hot, Humid Environment“. Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc794927/.
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A common measurement of body temperature during exercise in a hot, humid environment is mean skin temperature collected from 3-12 sites on the body. However, such an approach fails to demonstrate localized differences in skin temperature that are likely to exist as a function of gender. The purpose of this study was to examine potential differences in skin temperature between men and women at 17 different locations on the body. Young women (21 ± 1 y; n = 11) and men (23 ± 3; n = 10) were recruited to complete a 60-min walk/jog interval protocol in a hot (34 ± 1 °C), humid (64 ± 8%) environment while skin temperature was measured. Data was analyzed using a repeated-measures ANOVA (p < 0.05) and location of interaction effects determined using a Fisher’s least squares difference test. We observed a higher change (p < 0.05) from baseline skin temperatures (ΔTsk) for women in three locations: left upper back (women: avg. ΔTsk = 4.12 ± 0.20 °C; men: avg. ΔTsk = 2.70 ± 0.10 °C), right upper back (women: avg. ΔTsk = 4.19 ± 0.07 °C; men: avg. ΔTsk = 2.92 ± 0.05 °C), and right mid-back (women: avg. ΔTsk = 4.62 ± 0.14 °C; men: avg. ΔTsk =3.55 ± 0.09 °C). Individual time differences between genders occurred after 7- (left upper back) and 15-min (right upper back, right mid-back) of exercise and were maintained until the end of exercise. Women have a greater increase in skin temperature at three locations on the back following the onset of exercise in a hot, humid environment. This report provides important information regarding the implications of women exercising in a hot, humid environment.
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Reynoso, Francisco J. „Modeling of near infrared laser-mediated plasmonic heating with optically tunable gold nanoparticles for thermal therapy“. Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45966.
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Clinical hyperthermia refers to treatment of tumors by heating the lesions between 40 and 45° C. Several clinical trials have demonstrated that hyperthermia provides significant improvements in clinical outcomes for a variety of tumors, especially when combined with radiotherapy. However, its routine clinical application is still not optimal and major improvements are needed. The temperature distributions achieved are far from satisfactory and improved temperature control and monitoring are still in need of further development.
The use of gold nanoparticles (GNPs) has emerged as a good method to achieve local heat delivery when combined with near-infrared (NIR) laser. GNPs have a plasmon resonance frequency that can be tuned to absorb strongly in the NIR region where tissue absorption of laser light is minimal, allowing for less tissue heating and better penetration. For further development of the technique and appropriate clinical translation, it is essential to have a computational method by which the temperature distribution within the tumor and surrounding tissue can be estimated. Previously, our group developed a technique to estimate the temperature increase in a GNP-filled medium, by taking into account the heat generated from individual GNPs. This method involved a two-step approach combining the temperature rise due to GNPs and the solution to the heat equation using the laser light as heat source. The goal of this project was to develop a one-step approach that calculates the temperature distribution using the solution to the heat equation with multiple heat source terms, the laser light, and each individual GNP. This new method can be of great use in
developing a treatment planning technique for GNP-mediated thermal therapy including hyperthermia.
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Miller, William Harley. „AN INTRODUCTION TO A HYPERTHERMIA PATIENT PLANNING AND PATIENT TREATMENT EVALUATION SYSTEM (NUMERICAL, CANCER)“. Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275373.
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Lee, B. „Cross acclimation : the effect of prior acute and repeated heat exposures on physiological responses and performance in acute normobaric hypoxia“. Thesis, Coventry University, 2014. http://curve.coventry.ac.uk/open/items/54b8590a-13db-4ec9-a2ff-ecbfd07ad08b/1.
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The independent effects of acute heat and hypoxic stress on human physiological function and performance are relatively well documented. Although in the field these environmental stressors rarely occur in isolation the effects of combined or sequential exposure to them has not been extensively studied in humans. Animal models have however shown that acclimation to one stressor can induce ‘cross acclimation’ a positive adaptive response upon exposure to a different stressor. The three studies within this thesis were conducted in humans to assess how exposure to acute and repeated exposures to heat affects the later physiological and cellular responses to acute exercise in normobaric hypoxia. A possible site for any cross-acclimatory affects and conferred cellular tolerance resides in the heat shock response (HSR) and the increased expression of heat shock proteins (HSPs). The 72 kilodalton HSP, HSP72 has been implicated in heat acclimation mediated cross acclimation in rodent models, and also shown to be important in the human adaptation to heat and hypoxic stressors. Study One determined the physiological and HSR to exercise in both heat (HEAT; 40°C) and hypoxia (HYP; FIO2 0.14) alone, and in combination (COM) as well as a normothermic normoxic control (NORM). 24 hours after the initial exposure a hypoxic stress test (HST; 15 minutes of seated rest and 60 minutes of cycling exercise at 50% normoxic peak) was conducted to determine what effect the prior stress exposure had on both whole body physiological responses and the cellular HSR. It was hypothesised that the stressor that elicited the greatest physiological strain and HSR on day one would have the biggest effect on reducing physiological strain in a subsequent HST. Twelve male participants completed 4 trials consisting of a 15 minute rest period in normoxic temperate conditions, followed by 30 minutes seated rest and 90 minutes cycling exercise at 50% Npeak within NORM, HEAT, HYP and COM. 24 hours after completing this exercise bout, participants undertook a HST. Exercise duration was reduced in HEAT (78 ± 12mins), HYP (81 ± 13mins) and the CON (73 ± 19mins) trial compared to the NORM (89 ± 3mins). HR and core body temperature (Tcore), and thus physiological strain, were greater in the HEAT and COM trial compared to HYP alone. This response was also observed with post exercise monocyte HSP72 (mHSP72). Basal HSP72 was elevated 24 hours after the HEAT and COM and attenuated post HST. Exercising HR, Tcore and PSI was reduced during the HST 24 hours after a heat stressor had been applied, but unaffected by a prior hypoxic exposure. Therefore the hypothesis was accepted. It was concluded that at the temperature and level of hypoxia studied, a prior exposure to exercise heat stress was beneficial when conducting subsequent acute hypoxic exercise. Study Two investigated the effect of short-term heat acclimation (STHA) on subsequent hypoxic tolerance in 16 male participants divided equally into 2 matched groups. This study also examined the response of extracellular HSP72 (eHSP72) to acute hypoxic exercise. It was hypothesized that STHA would increase basal HSP72 and that the post HST increase in HSP72 would be attenuated in this group, indicating conferred cellular tolerance. Eight males completed a HST one week before undertaking 3 consecutive days of STHA (60 min/day, 40°C, 50%peak) followed by a final HST 48-hours after the last acclimation day. The matched controls (CON) completed an identical protocol in normothermic, normoxic conditions. The initial HST induced a post exercise increase in HSP72 in both groups. HSP72 was increased after the first day of heat acclimation and unchanged in the control group. After acclimation day 2, basal HSP72 was increased from on day 1 basal values and the post exercise increase observed on day 1 was absent in the heat group. The increase in basal HSP72 persisted until the post acclimation HST for the STHA group and post exercise HSP72 was attenuated. eHSP72 increased immediately after the HST in both groups, however large inter-individual variation was evident. Mean exercising HR, Tcore and physiological strain was reduced during the HST in the STHA group, indicating that a short period of heat acclimation can improve both cellular and physiological tolerance to exercise in acute normobaric hypoxia. Study Three examined how a prior period of long term heat acclimation (LTHA) or time and absolute exercise intensity matched hypoxic acclimation (HA) affects both tolerance and performance to a HST and 16.1 km time trial (TT). Plasma hypoxia inducible 1 alpha (HIF-1α) was assessed before and after the acclimation periods as this transcription factor plays an important role in heat acclimation mediated cross tolerance. Twenty-one male participants completed ten 60-minute cycling bouts (50% Npeak) in thermoneutral, normoxic conditions (CON, 18°C, FIO2 0.209; n = 7), heated conditions (LTHA, 40°C, n = 7) or hypoxic conditions (HA, FIO2 0.14, n = 7). A HST immediately followed by a 16.1 km TT was completed one week before and 48 hours after the acclimation period. Both LTHA and HA induced increases in basal HSP72 by the end of the 10-day period. Increases in basal HSP72 occurred earlier in the acclimation period and to a greater magnitude with LTHA. Prior to the post acclimation HST both basal HSP72 and plasma HIF1-α were elevated in the LTHA and HA groups, with no changes observed in CON compared to the initial HST. Post HST mHSP72 and HIF1-α was attenuated in LTHA and HA. Mean exercising HR, Tcore and PSI were reduced in the LTHA group with no changes in these physiological variables observed in the HA or CON groups. During the TT, mean power output (MPO) was elevated at each kilometer in the HA group, leading to an improved performance after acclimation. The LTHA group produced greater power outputs between km 1 – 8 and 14-16 and consequently were faster overall compared to their pre acclimation TT. This indicates an altered pacing strategy following the LTHA period. The data suggests that, at the levels studied herein, LTHA induces a faster accumulation of basal mHSP72 over a 10-day period, occurring to a greater magnitude. This is the first study to examine the plasma HIF-1α response to both heat and hypoxic acclimation in humans. The data suggest that each environmental stressor induces an increase in resting levels of this transcription factor, however further study is required due to the large variation in response. It is not yet known whether the benefits conferred from heat to acute bouts of hypoxia would translate to more prolonged hypoxic exposures. Both the mechanisms of cross-acclimation and the effects of extended or prolonged hypoxic exposure following heat acclimation require further study. The immediate post exercise mHSP72 increase to exercise was consistently shown to be greater following a heat stress condition when compared to hypoxia. STHA induced greater increases in basal mHSP72 compared to the acute exposure, further attenuating post HST mHSP72 elevations and physiological strain. LTHA increased basal mHSP72 at a faster rate and magnitude than HA and 16.1km time trial performance improved to a similar magnitude following both heat and hypoxic acclimation It is speculated that heat acclimation mediated activation of HIF-1α may hold a key mechanistic role in the observed cross-acclimatory response. From a practical perspective, the use of heat-stress based acclimation/training programs may provide a cheaper and more effective means of preparing individuals for subsequent hypoxic exposure. Future studies should confirm these observations hold true in a hypobaric environment and establish how prior heat acclimation may impact on longer term exposures and adaptations to hypoxic environments.
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Kim, Seong-Han. „The effects of heat stress on operator perceived workload in tracking“. Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-02132009-171117/.
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Zaerr, Jon Benjamin 1963. „Development and evaluation of a dynamic phantom using four independently perfused in vitro kidneys as a tool for investigating hyperthermia systems“. Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/291341.
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A dynamic phantom for use in investigating hyperthermia heating systems has been designed, constructed, and tested. A computer controlled the flow rate of 80% Ethanol to each of 4 preserved in vitro canine kidneys which acted as the phantom material. The flow rates were regulated with stepper motor controlled valves and measured with flow meters by the computer. This provided a flexible system for adjusting the perfusion as desired. The system was tested with step and ramp changes in perfusion under constant power ultrasound and with a temperature controlled perfusion algorithm, all of which yielded repeatable results. The dynamic phantom developed in this work shows potential for expediting investigations of hyperthermia controllers, temporal blood flow patterns, and inverse problems. Its computer based nature gives it great flexibility which would lend itself well to automated testing procedures.
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Di, Corleto Ross, und mikewood@deakin edu au. „The Evaluation of heat stress indices using physiological comparisons in an alumina refinery in a sub-tropical climate“. Deakin University, 1998. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050915.124324.
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The production of alumina involves the use of a process known as the Bayer process. This method involves the digestion of raw bauxite in sodium hydroxide at temperatures around 250°C. The resultant pregnant liquor then goes through a number of filtering and precipitation processes to obtain the aluminium oxide crystals which are then calcined to obtain the final product. The plant is situated in a sub tropical climate in Northern Australia and this combined with the hot nature of the process results in a potential for heat related illnesses to develop. When assessing a work environment for heat stress a heat stress index is often employed as a guideline and to date the Wet Bulb Globe Temperature (WBGT) has been the recommended index. There have been concerns over the past that the WBGT is not suited to the Northern Australian climate and in fact studies in other countries have suggested this is the case. This study was undertaken in the alumina plant situated in Gladstone Queensland to assess if WBGT was in fact the most suitable index for use or if another was more applicable. To this end three indices, Wet Bulb Globe Temperature (WBGT), Heat Stress Index (HSI) and Required Sweat Rate (SWreq) were compared and assessed using physiological monitoring of heart rate and surrogate core temperature.
A number of different jobs and locations around the plant were investigated utilising personal and environmental monitoring equipment. These results were then collated and analysed using a computer program written as part of the study for the manipulation of the environmental data . Physiological assessment was carried out using methods approved by international bodies such as National Institute for Occupational Safety & Health (NIOSH) and International Standards Organisation (ISO) and incorporated the use of a Physiological Factor developed to enable the comparison of predicted allowable exposure times and strain on the individual.
Results indicated that of the three indices tested, Required Sweat Rate was found to be the most suitable for the climate and in the environment of interest. The WBGT system was suitable in areas in the moderate temperature range (ie 28 to 32°C) but had some deficiencies above this temperature or where the relative humidity exceeded approximately 80%. It was however suitable as a first estimate or first line indicator. HSI over-estimated the physiological strain in situations of high temperatures, low air flows and exaggerated the benefit of artificial air flows on the worker in certain environments ie. fans.
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O'Sullivan, Joseph C. „The effect of diazoxide upon heat shock protein expression and physiological response to hemorrhagic shock and cerebral stroke“. Download the dissertation in PDF, 2006. http://www.lrc.usuhs.mil/dissertations/pdf/O'Sullivan2006.pdf.
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Huggett, Jenny A. „The effect of chlorine, heat and physical stress on entrained plankton at Koeberg Nuclear Power Station“. Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/17079.
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Bibliography: pages 112-138.The large volume of seawater used for cooling at Koeberg Nuclear Power Station contains many planktonic organisms which are exposed to heat, chlorine and physical stress during their passage through the system. Phytoplankton biomass, measured as chlorophyll a, was reduced by an average of 55.32% due to entrainment, and productivity was decreased by 38.30% on average, mainly due to chlorination. Zooplankton mortality averaged 22.34% for all species and 30.52% for copepods, the dominant group. The copepod Paracartia africana was used in laboratory experiments designed to simulate entrainment. Latent mortality was monitored up to 60 hours after a 30-minute application of stress factors (physical stress was not simulated), and approximately 75% of the total mortality occurred within the 30-minute period. Male Paracartia experienced higher mortalities than females. Extrapolation of these results predicts an overall entrainment mortality (including latent mortality) of 40% for copepods and 29.04% for total zooplankton, although the latter cannot be substantiated. Plankton entrainment at Koeberg was not considered to be overly detrimental to the marine environment because of the very localised area affected, rapid dispersion of heat and chlorine, rapid regeneration times of phytoplankton and some zooplankton, low abundance of commercially important species and potential recruitment from the surrounding productive Benguela upwelling region.
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Soares, André Luiz. „Análise do estresse térmico por calor na produtividade de operadores em uma fundição“. Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/935.
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A Ergonomia busca em sua essência adaptar o trabalho ao homem, usando de diversas ferramentas para atingir este objetivo, entre elas a análise ambiental. As características do ambiente como ruído, temperatura e iluminação podem influenciar o trabalho de um funcionário, e por isso necessitam ser avaliadas para verificar o seu efeito sobre a saúde dos trabalhadores e sua capacidade de trabalho. O estresse térmico, causado por calor, é a condição onde tanto o sistema fisiológico quanto o sistema psicológico são afetados pela temperatura do ambiente em que se encontra, quando esta temperatura encontra-se em níveis extremos, e pode causar efeitos como: hipertermia, tontura, desidratação, dor de cabeça, entre outros. A proposta desta pesquisa foi avaliar o efeito quantitativo que os sintomas de estresse térmico podem causar na produtividade de operadores em uma fundição. Foram empregadas duas normalizações para analisar o estresse térmico: ISO 7243 (1989), a qual apresenta a metodologia do Índice de Bulbo Úmido Termômetro de Globo (IBUTG), e ISO 7933 (2004), a qual apresenta a Taxa Requerida de Suor. Após a coleta de dados ambientais e pessoais em seis pontos diferentes do layout da fábrica, realizou análises de correlação e regressão linear entre os índices de estresse térmico e a produtividade para verificar a relação entre as mesmas. Os resultados demonstraram que a produtividade é inversamente proporcional ao nível de estresse térmico, e que o índice que apresenta a melhor correlação com a produtividade é o IBUTG, com coeficiente de determinação 94,05%, o que significa que 94,05% da variação encontrada para o tempo de vazamento de peças, indicador de produtividade, é justificada pela variação do índice IBUTG, indicador de estresse térmico. Os demais índices apresentaram correlações de 82,16% e 78,26%, e a regressão linear proporcionou em todos os métodos determinar uma equação para prever a produtividade em função da variação do estresse térmico.Ergonomics seeks in essence to adapt the work to the individual, using various tools to achieve this goal, including environmental analysis. The characteristics of the environment such as noise, temperature and lighting can influence the work of an employee, and therefore need to be evaluated to assess its effect on the health of workers and their working ability. The thermal stress caused by heat is the condition where both the physiological system as the psychological system are affected by the environment in which it is , when this temperature is in extreme levels, and can cause effects such as: hyperthermia, dizziness, dehydration, headache, among others. The purpose of this research was to evaluate the quantitative effect that the symptoms of heat stress can cause on the productivity of operators in a foundry. Two normalizations were used to analyze the thermal stress: ISO 7243 (1989), which presents the methodology of the Index Wet Bulb Globe Temperature (WBGT) and ISO 7933 (2004), which presents the Required Sweat Rate method. After collecting environmental and personal data in six different points of the foundry, it was conducted analyzes of correlation and linear regression between the index of thermal stress and productivity to verify the relation between them. The results showed that productivity is inversely proportional to the level of heat stress, and that the index that has the best correlation with productivity is the WBGT, with a determination coefficient 94.05% , ie 94.05% of the variation found for the time of casting parts, productivity indicator is justified by the variation of WBGT index. The other indices had correlations of 82.16 % and 78.26%, and the linear regression provided in all methods determine an equation to predict productivity as a function of the variation of heat stress.
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LAIBI, SAMI RESHAK. „EFFECT OF ENVIRONMENTAL FACTORS AND APPLIED GROWTH REGULATORS ON GROWTH, CYTOKININ PRODUCTION AND PHYSIOLOGICAL CHANGES OF PEPPERS (CAPSICUM ANNUUM L.) (ARIZONA)“. Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188004.
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Pepper plants (Capsicum annuum L.) were grown in field and a greenhouse in Arizona to determine the effects of water stress, root temperature, and exogenously applied growth regulators on cytokinin production and the resulting growth. Research showed that vegetative plants were significantly higher in cytokinin activity and growth parameters than fruiting plants. Also, in root-pruned fruiting plants, cytokinin activity was less than that of intact fruiting plants. In vegetative plants, the competition between removed sinks and the rest of the shoot was reduced and, hence, more cytokinin came from the roots to the shoots. Besides, additional carbohydrates were available and recycled to the roots. In respect to temperature effect, elevating temperature from 15 to 30°C had a pronounced effect of increasing the growth rate and cytokinin activity. The measured parameters declined when temperature exceeded 30°C. Temperatures between 25 and 30°C were found to be optimum. Under experimental conditions, growth regulators (Cytex® and Burst®) applied to the soil or foliage had no significant effect on growth rates or cytokinin activity in roots. Also, applying Burst® or kinetin to the nutrient medium had inconsistent and statistically nonsignificant effects on photosynthesis and transpiration.
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Anhalt, Dennis Paul 1960. „MODIFICATION OF A DIAGNOSTIC ULTRASOUND UNIT'S MOVEMENT SYSTEM TO PERFORM SCANNING DURING FOCUSSED, ULTRASOUND HYPERTHERMIA“. Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275546.
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Deresz, Fermino. „Effect of different cooling systems on concentrations of certain hormones and free fatty acids at varying times during lactation of Holstein cows“. Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184260.
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In experiment 1, fourteen cows were blocked for milk yields and balanced for days in lactation. Treatments were: (1) Air conditioning (AC), five cows; (2) Evaporative cooling (EC), four cows; and (3) Conventional shade (S), five cows. Sequential samples were taken for 8 h at 12 min intervals starting at 2200 and then at hourly intervals for 13 h. Serum was assayed for insulin, thyroxine (T4), triiodothyronine (T3) and cortisol using a double-antibody radioimmunoassay procedure. Free fatty acids (FFA) were determined in serum by an enzymatic method. In experiment 2, ten cows were blocked for milk yields and days in lactation. Treatments were: (1) Evaporative cooling (EC), five cows; and (2) conventional shade (S), five cows. Blood was drawn at 60 and 90 d of lactation. Blood sampling, hormone and FFA assays were carried out as in experiment 1. Sequential samples were taken for 8 h at 12 min intervals starting at 2300 and then at hourly intervals from 1030 to 1830. In experiment 1, insulin was depressed (P <.05) treatment effects for T3 in either experiment. There were significant treatment differences (P <.05) in respiration rates and body temperatures in experiment 1. Shade were higher than AC or EC cows. These studies demonstrated that summer heat stress depressed insulin and increased FFA with variable effects on T4 and cortisol but no effect on T3.
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Yaeram, Jakrit. „The effect of whole body heating on testis morphology and fertility of male mice“. Title page, table of contents and summary only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phj259.pdf.
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Higginbotham, Gerald Ernest. „Influence of protein level and degradability on performance of lactating cows during hot and cool environmental temperatures“. Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184265.
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One hundred and twenty lactating Holstein cows in mid-lactation were offered diets varying in protein level and degradability at two locations during hot and moderate weather. Treatments were: (1) High protein (19%), high degradability (65%); (2) High protein (19%), medium degradability (40%); (3) Medium protein (15.5%), high degradability (65%); (4) Medium protein (15.5%), medium degradability (40%). Diets were individually fed during hot weather at the University of Arizona Dairy Farm and contained 38.4% alfalfa hay, 12.4% cottonseed hulls, 9.8% whole cottonseed, and 39.4% concentrate (dry matter). Diets were group fed during moderate weather at the Brigham Young University Dairy Farm, Provo, Ut, and contained 31.3% corn silage, 14% alfalfa haylage, 9.4% whole cottonseed and 45.3% concentrate (dry matter). Average daily ambient temperatures were 35.1°C for hot and 26.8°C for moderate weather locations. Fat-corrected milk (3.5%, 2 x milkings) and milk persistency were lower for treatment 1 than other treatments. For the respective treatments during hot weather means were: 23.4, 26.6, 28.5, 28.4 kg/d; 83.2, 91.2, 90.9, 90.3%; and for moderate weather means were: (3 x milkings): 34.7, 31.8, 32.2, 32.4 kg/d; 97.0, 93.4, 92.1, 90.3%. Dry matter intakes during hot weather were 21.5, 21.9, 23.3, and 23.1 kg/d. Respiration rate and rectal temperature during hot weather were: 90.1, 87.9, 90.9, 94.7 counts/min; 39.0, 39.3, 39.3, 39.5°C and for moderate weather: 61.2, 58.2, 55.5, 67.4 counts/min; 38.8, 38.6, 38.7, 38.8°C. Serum T₃,T₄ and cortisol were generally unaffected by treatment, but were depressed during hot weather. Serum glucose was not significantly affected by treatments at either environmental locations. Animals consumed more water with highly degradable protein diets at each location along with consuming more water during thermal stress. These data show that 3.5% fat-corrected milk and milk persistency are significantly affected (P <.01; P <.025) by rations high in protein of high degradability during heat stress.
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Blood, Alan Physics Faculty of Science UNSW. „Biological effects of GSM mobile phone microwave radiation: an investigation of gene expression“. Awarded by:University of New South Wales. School of Physics, 2005. http://handle.unsw.edu.au/1959.4/22071.
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There is evidence that athermal radiofrequency radiation can alter Heat Shock Protein (HSP) expression or protein phosphorylation, or alter MAP kinase signalling. Effects of long-term exposure in brain tissue due to repeated HSP perturbation (eg an inhibition of apoptosis) have been hypothesised (French et al, 2001). This study aimed to investigate the RNA expression profile (12,000 genes) and HSP family protein expression levels after either acute 1-hour or chronic 4-day intermittent exposures to simulated GSM radiation in a human primary fibroblast model. The results found minimal or no effects of GSM. Flasks were exposed to 900 MHz (217 Hz modulation) at 0.18 W/kg SAR within a Transverse Electromagnetic Mode chamber (TEM cell). Cultures rested for 2 hours before exposures. Affymetrix U95A microarray analysis of a single pilot set of experiments showed that about 40 genes were reported as upregulated >=2.5 fold in each condition. There was no evidence of altered expression of any MAPK-associated genes. Target genes reported in both conditions (CBFA2T1, ZNF148, ITGA1), and genes altered in one condition (CCS, PLEC1, BIRC5), and marginally altered HSP72 were selected for PCR analysis. No other members of the HSP family were altered. In three replicate experiments assayed by real-time PCR, six genes were either unchanged or showed randomly variable expression. However HSP72 RNA showed possible consistent slight upregulation of 1.37 +/- 0.21 in the chronic condition. Western immunoblots of HSP-60, -70, -72 and -V90 proteins showed no significant changes 5 hours after exposure. In preliminary studies using a serum starvation protocol, ERK-1 phosphorylation was unaltered after 5 or 30 minutes GSM (single experiments). When flasks were transiently cooled, ERK-1 phosphorylation was increased 20 minutes later, indicating a source of artefact in some protocols. An inflammatory challenge experiment with a low-dose of the cytokine IL-1???? found that acute GSM exposure post-challenge inhibited NF????B-mediated GRO???? induction by 1.5 fold (2 experiments). Preconditioning with mild heat induces transient inhibition of both NF????B signalling and apoptosis. Other studies indicate that EMF exposures similarly evoke cytoprotection. It is suggested that GSM evoked cytoprotective signalling in this inflammatory model.
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Kessler, Jeffrey C. (Jeffrey Charles). „Physiological Effects of Monetary Consequences“. Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc278141/.
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Electrodermal responding (EDR) and heart rate (HR) were assessed for seven subjects participating in a reaction time task consequated with monetary bonuses (250, 100, and 10), monetary penalties (250,100, and 10), and a monetary neutral value (00). Unlike previous research employing group designs and a tonic measure (i.e., mean over long periods of time), this study utilized a single-subject design and a phasic measure (i.e., mean over 2-s intervals). Heart rate data was too variable for meaningful analysis. EDR data showed that the peak levels of EDR were higher for penalties than for the corresponding values of bonuses (e.g., -250 vs. +250) for most subjects. Similarly, peak levels of EDR were generally higher during sessions in which consequences were presented than in sessions during which consequences were absent.
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Woods, Barbara Jane Simmons. „Mirthful Laughter and Directed Relaxation: a Comparison of Physiological Response“. Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc331273/.
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The differences among certain physiological changes occurring in response to mirthful laughter, directed relaxation, and verbal speech were investigated. These changes included amount of muscle tension, as measured with surface electromyography, in the forehead and in the upper body as recorded from the forearms bilaterally, peripheral surface skin temperature, heart rate, and respiration rate. The study sought to determine whether the net effect of laughter, as measured on these five variables after a three-minute refractory period, is a more relaxed state than existed before the laughter. Determination of the similarity between the changes following laughter and the changes following directed relaxation was made in comparison with the changes following verbal speech. Factors of prior anxiety, pre- and post-self-esteem levels, humor level, and laughter intensity were examined. Historical and theoretical perspectives were reviewed, as well as the known information on physiological responses to laughter.
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Maune, Jerene Mary 1953. „THE EFFECT OF CAFFEINE ON HEART RATE, RHYTHM AND BLOOD PRESSURE“. Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276372.
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Zhang, Yi. „Implications of natriuretic peptides and endothelin-1 release during myocardial ischaemia“. Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phz6334.pdf.
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Addenda and corrigenda are tipped-in & numbered leaves 281-282. Copies of author's previously published articles are inserted back end paper. Bibliography: leaves 222-279. Studies were performed in the Langendorff-perfused isolated rat heart, using a paradigm in which atrial distension was prevented. The release of natriuretic peptides and endothelin-1, along with cardiac function was monitored during periods of transient ischaemia or hypoxia. Additional studies were performed in patients undergoing cardiac catheterization.
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Reed, Daniel Kelvin. „THE EFFECT OF HYPEROXIC GAS MIXTURES ON RECOVERY FROM SHORT-TERM MAXIMAL EXERCISE (VENTILATION, HEART RATE, PH)“. Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276382.
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Brunelle, Caroline. „The role of alcohol-induced cardiac reactivity in addiction : investigations into a positive reinforcement pathway“. Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102482.
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Alcohol abuse is the second most prevalent lifetime psychiatric disorder. However, individuals do not face an equal risk of developing problematic alcoholrelated behaviors. Alcohol use disorders are heterogeneous conditions whose development may be caused by a variety of factors and vulnerabilities. The identification of markers of risk is necessary in order to identify individuals at higher risk for addiction early on as well as to help develop treatment interventions which target an individual's specific risk factors. The goal of the present dissertation is to increase our understanding of the role that one putative risk factor, an exaggerated cardiac response to alcohol, may play in the development of addictive behaviors. Five studies are reported.The first study revealed that an exaggerated heart rate response to alcohol is associated with subjective reports of increased alcohol-induced stimulation. In a second study, the relationship between the cardiac response to alcohol and personality characteristics was examined. Individuals who demonstrated the elevated cardiac response to alcohol displayed a distinct personality profile characterized by high sensation-seeking and sensitivity to reward. Two separate studies followed investigating the relationship between this physiological response to alcohol and other addictive behaviours. One study found that individuals with an exaggerated cardiac response to alcohol were more likely to obtain superior scores on a measure of pathological gambling, while the next study found that users of psychostimulants (e.g., cocaine) also displayed heightened alcohol-induced cardiac responses. A final study examined the impact of conditioned cues of reward and non-reward on alcohol-induced cardiac responses. Individuals who had previously displayed elevated cardiac responses to ethanol showed reduced cardiac reactivity when alcohol ingestion occurred in a non-rewarding environment. Overall, these findings suggest that the cardiac response to alcohol is a marker of a pathway that may lead to addictive behaviors through increased sensitivity to incentive reward.
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何頌詩 und Chung-sze Joyce Ho. „Effects of preconditioning with metabolic inhibition or U50488H or high CA2+ on CA2+ homeostasis in ventricular myocytes subjected tosevere metabolic inhibition or high CA2+“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31226024.
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Torres, Esperanza. „THE EFFECTS OF CAFFEINE INGESTION ON FETAL HEART RATE IN PREGNANT COLOMBIAN WOMEN“. Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275340.
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Chung, Siu-fung, und 鍾少鳳. „A case control study on smoking, alcohol drinking and other risk factors of coronary heart disease in Hong Kong“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B29775334.
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Assaad, Jean-Marc. „The heart rate response to alcohol intoxication and its relationship with alcohol consumption, delinquency, and intoxicated aggressive and disinhibited behaviors /“. Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38457.
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Alcohol abuse/dependence frequently co-occurs with antisocial personality disorder (ASPD) and conduct disorder (CD). Furthermore, crime studies have generally found that alcohol is involved in over 50% of violent crimes, and experimental studies support the notion that acute alcohol consumption indirectly increases the likelihood of aggressive and disinhibited behaviors in the laboratory. However, the mechanisms underlying alcohol's association with such behaviors remain unclear. The goals of this thesis were therefore to further elucidate potential mechanisms underlying (a) alcohol-induced aggressive, disinhibited behaviors and (b) the high comorbidity between delinquent, aggressive behaviors (characterizing CD/ASPD) and alcohol misuse/abuse/dependence. Thus, four studies were conducted, focusing on individual differences in the physiological response to alcohol intoxication. Specifically examined was the elevated heart rate (HR) response to alcohol, which is thought to reflect an increased sensitivity to alcohol-induced reward.Results of Study I indicated that high HR Responders to alcohol self-reported increased multiple year delinquency (physical aggression, theft, and destruction of property), as well as more alcohol consumption and an increased positive subjective feeling following intoxication, as compared to low HR Responders. Furthermore, a high HR response was related to increased extraversion, disinhibition, boredom susceptibility, and total sensation seeking. Study II revealed that Aggressive Sons of Male Alcoholics (Agg-SOMAs) had the highest intoxicated HR response, and reported the most alcohol consumption, as compared to Non-Agg-SOMAs, or Agg - or Non-Agg - Non-SOMAs. Studies III and IV revealed that intoxicated high HR responders exhibited the most physical aggression (assessed by the Taylor Aggression Paradigm), as well as the most behavioral disinhibition (assessed by the Go/No-Go task) as compared to sober high HR Responders, or sober/intoxicated low HR responders.
In summary, individuals with a high HR response to alcohol appear to have an increased propensity for multiple addictive, disinhibited and aggressive behaviors. This determines a phenotype of both potential heuristic and clinical importance. These findings are discussed within the context of a hypothetical model of (a) the high comorbidity between alcohol use/misuse and aggression/ASPD, and (b) the increased likelihood of alcohol-induced aggressive, disinhibited behaviors.
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Fu, Shing-yan Karen, und 符誠欣. „Cigarette smoke-induced inflammatory changes in rat heart in vivo“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48333864.
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Cigarette smoke (CS) is a well-established risk factor to cardiovascular health and the most preventable cause of death. Countless studies have demonstrated its harm to health and many more studies investigating its pathogenic mechanisms. While the CS-induced pathogenic mechanism of cardiovascular dysfunction has been mainly attributed to a combination of oxidative imbalance, vascular endothelial dysfunction, inflammation and modification of lipid profile, the focus of the current study was on the mediators of inflammation and the activation of signal pathways. In this study, we investigated the effects of CS on the pro-inflammatory/anti-inflammatory status in the heart and to elucidate the activation of specific signaling pathways in an in vivo rat model. Male Sprague-Dawley rats were divided into groups of CS exposure and sham air (SA) and exposed to 1 hour of respective CS and SA exposure daily for 56 days. The rats were then sacrificed and the ventricular homogenates were examined. Cardiac pro- inflammatory and anti-inflammatory mediators such as C-reactive protein (CRP), interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (CINC-1), transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF) and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA) and the activation of specific signaling pathways was determined by Western blot analysis. CS caused suppression of cardiac CRP, IL-6, TGF-β1, and IL-10 and elevation of VEGF, revealing the imbalance of pro-inflammatory/anti-inflammatory status. Nuclear factor-κB (NF-κB) was also activated along with the activation of extracellular-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) but not p38 mitogen-activated protein kinase (MAPK) after 56 days of CS exposure. These data suggests the presence of a local adaptive mechanistic response to modulate cardiac pro-inflammatory/anti-inflammatory status via NF-κB/MAPK pathways after exposure to CS. These findings shed insight into the mechanistic pathways of CVD progression, allowing possible identification of selected mediators as biomarkers that could benefit early detection of CVD arisen from cigarette smoking.published_or_final_version
Pharmacology and Pharmacy
Master
Master of Medical Sciences