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  • 1
    ISSN: 1432-1246
    Keywords: Foundry welders ; Industrial heat exposures ; Thermal alliesthesia ; Work/rest regimen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A field study to optimize the work/rest regimen among foundry welders performing a light to medium work load and welding red-hot items was undertaken during the morning shift. Three work/rest regimens were tested, viz.: work(2h)/rest(1 h) with a team of three welders per shift work(1 h)/rest(1 h) with a team of four welders per shift work(2h)/rest(2h) with a team of four welders per shift. Pulse frequency and core temperature were measured at short intervals during working periods. Thermal alliesthesial reactions (used as a thermoregulatory behavioral indicator) were quantified by the aid of a 58 peripheral temperature stimulus of 15, 20, 25, 30, 35 and 38°C on hand, forehead, and back of neck. For each stimulus the subject voted his pleasantness sensation on a five point scale ranging from +10 for very pleasant to -10 for very unpleasant. Temperature stimuli were applied using a Peltier thermode 5.5 x 2.7 cm2 in area. The subject also voted his most pleasant temperature on back of neck by voluntary control. The results confirmed previous studies that thermoregulatory behavioral indicators are more sensitive than physiological (e.g., core temperature) indicators in revealing the thermal comfort state of man. The results indicated that the work(2h)/rest(2h) regimen was the most satisfactory of the three regimens tested and was associated with full recovery from thermal stress after the 2 h resting break. This work(2 h)/rest(2 h) regimen was then tested during afternoon and night shifts. The results indicated that the morning shift was more advantageous than the two other shifts with respect to cardiovascular load and thermal strain during working periods, although recovery from thermal stress was achieved after the 2 h resting break in all of the three shifts. Improvement of resting place ambient thermal conditions was proposed to shorten the downtime per man per shift. Radiation shielding of resting place was viewed as economic and effective under these conditions.
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  • 2
    ISSN: 1432-069X
    Keywords: 3H-8-MOP ; DNA-RNA protein activity ; 3H-8-MOP time activity curves ; Rat organs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tritiated 8-methoxypsoralen was given perorally to rats in amounts corresponding to therapeutic human doses. The rats were exposed to UVA light or kept in darkness. None of the fractions (apart from 3H2O from the lens) examined changed their level of radioactivity under the influence of UVA light. Time-radioactivity curves were recorded for the skin, lens, residual eye, and the liver. Four fractions were measured: 3H2O, soluble pool, DNA-RNA, and protein. Tritiated water appeared already 1 h after ingestion, and attained maximum value 9–24 h after ingestion, indicating the efficiency with which the liver degrades 8-MOP. 3H-8-MOP and metabolites could be detected in the soluble pool in maximum amounts 2–3 h after the administration. Pretreatment with trypsin increased the concentration of 3H-8-MOP and metabolites; the origin of this extra radioactivity was the protein fraction. The 3H-8-MOP binding to DNA or RNA was studied by pretreatments of the homogenates with DNase or RNase followed by measurement of radioactivity in the TCA extracts. This indicated that no measurable amount of 3H-8-MOP had been bound to DNA or RNA. We conclude that 8-MOP administered to rats in amounts corresponding to human therapeutic doses does not bind to DNA or RNA in measurable amounts either after UV-light or in darkness. The experiments have shown proteins to be the main binding site in rat organs.
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 40 (1984), S. 87-87 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
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  • 4
    ISSN: 1432-1246
    Keywords: Alliesthesia ; Circadian variations ; Onset of sweating ; Thermal comfort ; Thermoregulatory set point
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Different methods of quantifying thermal alliesthesia were used to examine the circadian variations of thermal comfort. At eight different times of the 24 h day, four subjects were exposed to a constant room temperature of 25°C. After 30 min rest, the subjects performed 50 W bicycle ergometer work for 45 min. A 5 s temperature stimulus of 15°, 20°, 25°, 30°, 35°, and 38°C was applied on the hand, forehead, and back of the neck. For each stimulus the subjects voted their degree of thermal comfort on the subjective thermal comfort scale, ranging from +2 for very pleasant to −2 for very unpleasant. The most pleasant temperature on the back of the neck was chosen by voluntary control. This procedure was performed at the start and repeated every 15 min throughout the exposure time. A 5:5 × 2.7 cm2 Peltier thermode was used to give the temperature stimuli. Voluntary control voting was carried out using the temperature control knob without looking at the temperature scale of the thermode. The results suggest that during rest in a state of thermal neutrality the core temperature is about 0.06°C lower than the thermoregulatory set point (Cabanac et al. 1976; Strempel et al. 1976). This deviation (Trect - Tset) from the set point is known in man-made servo-systems as the load error (Benzinger 1979). During rest in an atmosphere of thermal comfort, the “load error” in the human thermostat is found to be negative (Cabanac et al. 1976; Strempel et al. 1976; Benzinger 1979), i.e., Tset 〉 Trect, where Trect is the prevailing core temperature and Tset, is the thermoregulatory set point. The small deviation from the set point is viewed as being necessary to sustain the response and to keep the temperature in equilibrium between production and loss of heat (Benzinger 1979). Thermal comfort limits during work rise from the early morning to the afternoon and then fall slowly towards the minimum level in the morning. The circadian variations of the core temperature load error associated with onset of sweating have a phase shift of 180° (12 h) with the alliesthesial reactions. Using our results and the results from Cabanac et al. (1976), it has been possible to write a circadian thermoregulatory set function to estimate the set point at any point of day time.
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  • 5
    ISSN: 1439-6327
    Keywords: Thermal comfort ; Thermal pleasantness ; Thermal stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The degree of pleasantness or unpleasantness of thermal sensation aroused by a particular peripheral thermal stimulus has been shown to be an indicator of thermal state of the body in relation to the thermoregulatory set point. This phenomenon is known as thermal alliesthesia. The quantification of thermal alliesthesia was possible using two methods: (1) A set of temperature stimuli (15, 20, 25, 30, 35, and 38
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  • 6
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two sibs with the acute neonatal form of glutaric aciduria type II (deficientin vivo activity of multiple acyl-CoA dehydrogenases) are described. In the second case diagnosis was made prenatally on the basis of reduced oxidation of palmitate by cultured amniotic fluid cells. With prompt intervention in the neonatal period and a carefully controlled diet later, this second case progressed well up to 4 months of age but died suddenly of cardiac failure, probably attributable to accumulation of fat. Neither patient showed any congenital morphological abnormality. Cultured fibroblasts from the second case showed a marked defect in the oxidation of a range of substrates requiring acyl-CoA dehydrogenases for their catabolism, but residual activity for some substrates was quite high. Large quantities of sarcosine were excreted in urine, again suggesting that the mutation leaves some residual dehydrogenation activity. Butyryl-, octanoyl- and palmitoyl-CoA dehydrogenases were present in essentially normal quantities in postmortem liver.
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