| heat of dissociation | The heat (expressed in calories or joules) expended in the dissociation of 1 mol of a substance into specified products. (05 Mar 2000) |
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| heat of evaporation | The heat absorbed in the evaporation of water, sweat or other liquid; for water it amounts to 540 cal/g at 100캜. Synonym: heat of vaporization. (05 Mar 2000) |
| heat of formation | The heat (expressed in calories or joules) absorbed or liberated during the (hypothetical) reaction in which a mole of a compound is formed from the necessary elements, in elemental form. (05 Mar 2000) |
| heat of fusion | <chemistry> The enthalpy change that occurs to melt a solid at its melting point. (09 Jan 1998) |
| heat of hydration | <chemistry> The enthalpy change associated with placing gaseous molecules or ions in water. (09 Jan 1998) |
| heat of solution | <chemistry> The enthalpy change associated with dissolving a solute in a solvent. (09 Jan 1998) |
| heat of vaporization | <chemistry> The energy required to vaporise one mole of a liquid at a pressure of one atmosphere. (09 Jan 1998) |
| heat prostration | A form of heat illness that results when the victim is dehydrated (fluid depleted). Common symptoms include: fatigue, lightheadedness, nausea, vomiting, headache, rapid heartbeat and lowered blood pressure. (27 Sep 1997) |
| heat rash | An eruption of papules and vesicles at the orifices of sweat glands, accompanied by redness and inflammatory reaction of the skin. Synonym: heat rash, lichen infantum, lichen strophulosus, prickly heat, strophulus, summer rash, tropical lichen, lichen tropicus, wildfire rash. (05 Mar 2000) |
| heat rate | The amount of fuel energy required by a power plant to produce one kilowatt-hour of electrical output. A measure of generating station thermal efficiency, generally expressed in Btu per net kWh. It is computed by dividing the total Btu content of fuel burned for electric generation by the resulting net kWh generation. (05 Dec 1998) |
| heat rigor | Coagulation of muscle protein induced by heat. (05 Mar 2000) |
| heat-rigor point | <cell biology> The degree of elevated temperature at which coagulation of protoplasm occurs with death of the cell. (05 Mar 2000) |
| heat-shock factor | <cell biology, protein> A class of molecular chaperones found in both prokaryotes and in several compartments of eukaryotic cells. There is evidence that these proteins can interact with polypeptides during a variety of assembly processes in such a way as to prevent the formation of nonfunctional structures. (12 Dec 1998) Previous: heat-shock factor, heat-shock gene, heat-shock protein, heat-shock protein 27 kinaseNext: heat-shock proteins 90, heat-shock responseheat-shock factor -->heat-shock proteins 90 <cell biology, protein> A class of molecular chaperones whose members act in the mechanism of signal transduction by steroid receptors. (12 Dec 1998) |
| heat-shock gene | <molecular biology> A set of genes present in most animals which are transcribed suddenly, quickly, and with coordination when the animal is exposed to certain types of stress such as a sudden temperature increase. (09 Oct 1997) |
| heat-shock protein | <cell biology, molecular biology, protein> Families of proteins conserved through prokaryotic and eukaryotic cells and bacteria in response to hyperthermia and other environmental stresses, although some are constitutively expressed. They increase thermal tolerance and perform functions essential to cell survival under these conditions. Some serve to stabilise proteins in abnormal configurations, play a role in folding and unfolding of proteins and the assembly of oligomeric complexes and may act as chaperonins. Hsp90 complexes with inactive steroid hormone receptor and is displaced upon ligand binding. Four major sub classes are recognised: hsp90, hsp70, hsp60 and small hsps. Hsps have been suggested to act as major immunogens in many infections. Acronym: HSP (12 Dec 1998) |