| negative regulation | Negative feedback in biological systems mediated by allosteric regulatory enzymes. (18 Nov 1997) |
|---|---|
| down-regulation | <physiology> Development of a refractory or tolerant state consequent upon repeated administration of a pharmacologically or physiologically active substance. It is the process that decreases ligand and receptor interactions or reduces the responsiveness of a cell to a stimulus following first exposure. This is often accompanied by an initial decrease in affinity of receptors for the agent and a subsequent reduction in the number of available receptors expressed on the surface which can result from internalisation of the ligand:receptor complex or from decreased expression of the receptor. Classically the concept referred to hormone receptors but contemporary usage includes other cell surface receptors. (03 Jul 1999) |
| target regulation | <physiology> General term for an interaction between neurons and their targets by which target derived signals influence the differentiation of the innervating neurons. (18 Nov 1997) |
| enzyme regulation | <biochemistry> Control of the rate of a reaction catalyzed by an enzyme by some effector (e.g., inhibitors or activators) or by alteration of some condition (e.g., pH or ionic strength). (05 Mar 2000) |
| facility regulation and control | Formal voluntary or governmental procedures and standards required of hospitals and health or other facilities to improve operating efficiency, and for the protection of the consumer. (12 Dec 1998) |
| feedback regulation | <physiology> Control mechanism that uses the consequences of a process to regulate the rate at which the process occurs: if, for example: the products of a reaction inhibit the reaction from proceeding (or slow down the rate of the reaction), then there is negative feedback, something that is very common in metabolic pathways. Positive feedback is liable to lead to exponential increase and may be explosively dangerous in some cases. Other examples are the action of voltage dependent sodium channels in generating action potentials and the activation of blood clotting factors V and VIII by thrombin. Without damping, feedback can lead to resonance (hunting) and oscillation in the system. (18 Nov 1997) |
| up-regulation | Opposite of down-regulation. (05 Mar 2000) |
| up-regulation (physiology) | Process that increases ligand/receptor interactions due to an increase in the number of available receptors. (12 Dec 1998) |
| atomic heat | The amount of heat required to raise an atom from 0 |
| radiant heat | Heat given off from any body in the form of waves, similar to light waves but of greater wavelength. (05 Mar 2000) |
| molar heat capacity | <chemistry> The amount of energy required to raise the temperature of one mole of a substance by one degree Celsius (or Kelvin). (09 Jan 1998) |
| molecular heat | The product of the specific heat of a body multiplied by its molecular weight. (05 Mar 2000) |
| combined heat and power | An older term for what is now generally called cogeneration. The term is currently used in Europe and other foreign countries. (05 Dec 1998) |
| conductive heat | Heat transmitted by direct contact, as by an electric pad or hot water bottle. (05 Mar 2000) |
| convective heat | Heat conveyed by a warm medium, such as air or water, in motion from its source. (05 Mar 2000) |