Temperature, environmental

When administered intraperitoneaHy, sulfolane is excreted both unchanged and as 3-hydroxysulfolane [13031 -76-0] (24). Sulfolane injected intraperitoneaHy in mice and rats at 200—800 mg/kg at ambient temperatures of 15 and 25°C caused a dose-related inhibition of the metaboHc rate and hypoactivity, accompanied by hypothermia 60 min after injection. Despite their hypothermic condition these animals did not select a warm ambient temperature. Because sulfolane toxicity appears to be greater upon increased tissue temperature, the behavior of these animals seeking lower environmental temperature appears to enhance their chance of survival (25—28). 

Organisms evolving under aimual temperature cycles and in environments with varying temperatures spatially have incorporated thermal cues in reproductive behavior, habitat selection, and certain other features which act at the population level. Thus, the balance of births and mortaUties, which determines whether a species survives, is akin to the metaboHc balance at the physiological level in being dependent upon the match, within certain limits, to prescribed temperatures at different times of year. At the ecosystem level, relationships among species, eg, predators, competitors, prey animals, and plant foods, are related to environmental temperatures in complex ways. Many of these interactions are poorly understood. 

E. Ronde, H. Bechen, and M. Metzger, Kautsch. Gummi, Kunstst. 42, 1121 (1989) E. Ronde. H. Bechen, and M. Mezger, Polychloroprene Grades and Compoundingfor Eong Term Flexibility atEow Environmental Temperatures, Scandinavian Rubber Conference SCR/1989, Tampere, Einland, Jan. 30,... 

With heavy fuels, the ambient temperature and the fuel type must be considered. Even at warm environmental temperatures, the high viscosity of the residual could require fuel preheating or blending. If the unit is planned for operation in extremely cold regions, the heavier distillates could become too viscous. Fuel system requirements limit viscosity to 20 centi-stokes at the fuel nozzles. 

The operating environmental temperature has an effect on the carbon canister performance [20]. Fig. 14 shows a 10% degradation in GWC as the environmental temperature increases from 25 to 80 °C. The hydrocarbon heel decreases by 55% during the same test. The hot environment helps to pui ge out the canister, but adsorption is reduced under the same conditions. Ideally the canister would be packaged in an area where it would not pick up heat from vehicle operation. 

Olsson, P., and Bende, M. (198.5). Influence of environmental temperature on human nasal mucosa. Ann. Otol. Rhinol. Laryngol. 94, 1.53-155. 

Environmental temperature A design value used by the CIBSE in heating and cooling calculations, equal to 0.33 6, + 6. ... 

The effect of high or low environmental temperature on skilled performance is important for industrial or service personnel. Operators often have to work in extreme thermal conditions, such as in furnaces or when they need to operate a pump in cold weather at night. Errors of omission are quite often due to the workers trying to minimize the time period they have to be exposed to high or low temperatures. Particular emphasis has been placed on the effects of cold on manual performance. Cold can affect muscular control, reducing such abilities as dexterity and strength. 

Internal environmental temperature required = 15°C. External air temperature = —3°C. 

Ablative systems are not limited by the heating rate or environmental temperature, but rather by the total heat load. In spite of this limitation, however, the versatility of ablation has permitted it to be used on various hypervelocity atmospheric vehicles. No single, universally acceptable ablative material has been developed. Nevertheless, the interdisciplinary efforts of materials scientists and engineers have resulted in obtaining a wide variety of ablative compositions and constructions. These thermally protective materials have been arbitrarily categorized by their matrix composition, and typical materials are given in Table 2-9. 

Thus by analyzing the thermal limits of the various materials available, starting with the maximum and minimum environmental temperatures under which a product must operate and adding any thermal increase... 

Some fifty years ago, a classic theoretical paper (Urey 1947) proposed that the oxygen isotope ratio ( 0/ 0) in various minerals depends on two variables the local environmental temperature and the oxygen isotopic ratio in the environmental water. The proposal was verified experimentally in carbonates (Epstein et al. 1951, 1953 McCrea 1950) where the oxygen isotope ratio is dependent on the temperature of formation and the ratio in... 

PFPE, AI2O3, and X-IP were 500 mg, 200 mg, and 100 mg, respectively. The materials in Samples 2 to 4 were sufficiently mixed to ensure that the liquid PFPE and X-IP completely wet the alumina powders. These specimens were put in a closed space hlled with inert nitrogen. The flow rate of the nitrogen gas was kept at 20 milliliters per minute. The environmental temperature of the system was set at 220 ° C and the duration time was 250 minutes per sample for each individual operation procedure. PFPE used in the experiment was Z-dol and the alumina was in ultra-fine powders with chemical analytic grade purity. 

The melting points of even-numbered-carbon fatty acids increase with chain length and decrease according to unsaturation. A triacylglycerol containing three sam-rated fatty acids of 12 carbons or more is solid at body temperature, whereas if the fatty acid residues are 18 2, it is liquid to below 0 °C. In practice, natural acylglyc-erols contain a mixture of fatty acids tailored to suit their functional roles. The membrane lipids, which must be fluid at all environmental temperatures, are... 

Egaas E, U Varanasi (1982) Effects of polychlorinated biphenyls and environmental temperature on in vitro formation of benzo[a]pyrene metabolites by liver of trout (Salmo gairdneri). Biochem Pharmacol 31 561-566. 

Heat shock proteins (HSPs) are synthesized by cells in response to an increase in temperature, as well to various other stressful stimuli. Their main function is to ensure intracellular protein homeostasis, thus preserving the cells viability in the presence of aggression. Current evidence points to a protective role for HSPs in several aspects of critical disease, such as ischemia-reperfusion, ARDS, and multiple organ failure. The increase of a few degrees Celsius above the normal environmental temperature of cells leads to the heat shock response 1) rapid expression of heat shock genes, 2) suppression of normal protein synthesis, and 3) the ability of cells to survive a second and otherwise lethal heat challenge (thermotolerance). 

MM deVilliers, JG Van der Watt, AP l.otter. Interconversion of the polymorphic forms of chloramphenicol palmitate (CaP) as a function of environmental temperature. Drug Dev Ind Pharm 17(10) 1295—1303, 1991. 

If the environmental temperature is constant, the racemization process takes place at a uniform rate, which is determined, at any time during the process, by the relative amounts of / and d forms of the amino acid can be measured. As the racemization proceeds and the concentration of the / form amino acid decreases, the rate of racemization gradually slows down. When there is a mixture of 50% of each of the d and / forms, the racemization process stops altogether. The half-life of the racemization of aspartic acid, for example, a common amino acid in proteins, at 20°C is about 20,000 years. This half-life makes it possible to date proteins as old as about 100,000 years. So far, however, the dates obtained with the technique have proved somewhat inconsistent, probably because of the difficulty in verifying whether the temperature of the amino acids has been constant. 

FIGURE 23 Hydration layer in obsidian. When obsidian is broken into two or more pieces, new surfaces are created. As a new surface is exposed to the environment, water (from atmospheric humidity, rain, or the ground) penetrates the surface gradually, the water diffuses into the bulk and forms hydrated obsidian, that is, obsidian containing water. With time, the thickness of the hydration layer, as such a layer is known, gradually increases the rate of increase is affected by such factors as the vapor pressure of the water in the atmosphere, the environmental temperature, and the composition of the surrounding environment as well as of the obsidian. If the hydration layer reaches a thickness of 0.5 microns or more, it becomes discernible under a microscope, the thickness can be measured, and the age of the surface calculated. The microphotograph shows an hydration layer on obsidian. 

In this barrel, air is expected to come naturally. Temperature and leachate volume were measured twice a week. Once a week, waste was taken out to mix with air and then put back into the barrel. At the same time, sample was taken to measure water content. Stabilization step ended when waste body stopped generating water, varied from 18 to 51 days, due to waste input characteristic and environmental temperature. After this time, raw RDF was collected and stored for further analysis. Stabilization time of El > E3 and R1 > R3 was compared with that of other study (Table 8). 

Bowyer, J.F., Tank, A.W., Newport, G.D. et al. The influence of environmental temperature on the transient effects of methamphetamine on dopamine levels and dopamine release in rat striatum. J. Pharmacol. Exp. Ther. 260 817, 1992. 

Ali, S.F., Newport, G.D., Holson, R.R., Slikker, W.J., Bowyer, J.F. Low environmental temperatures or pharmacologic agents that produce hypothermia decrease methamphetamine neurotoxicity in mice. Brain Res. 58 33, 1994. 

---