| thermodynamic equilibrium | <radiobiology> There is a very general result from statistical mechanics which states that, if a system is in thermodynamic equilibrium with another (or several other) system, all processes by which the systems can exchange energy must be exactly balanced by their reverse processes, so that there is no net exchange of energy. For plasma systems in thermodynamic equilibrium, ionisation must be balanced by recombination, Bremsstrahlung by absorption, and so on. When thermodynamic equilibrium exists, the distribution function of particle energies and excited energy levels of the atoms can be obtained from the Maxwell-Boltzmann distribution (which is a function only of the temperature). The Saha equation is a special application of this. (09 Oct 1997) |
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| equilibrium | Balance A condition in which no further net change is occuring in a system, and free energy is minimimal. (09 Oct 1997) |
| equilibrium centrifugation | A type of density gradient centrifugation used to separate proteins or nucleic acids from a mixture. (09 Oct 1997) |
| equilibrium constant | <chemistry> The ratio of the reverse and forward rate constants for a reaction of the type: A + B = AB at equilibrium the equilibrium constant (K) equals the product of the concentrations of reactants divided by the concentration of product and has dimensions of concentration. Kd = (concentration A.concentration B) / (concentration AB). The affinity constant (Ka) is the reciprocal of the equilibrium constant. Dimension: moles per litre. In general the concept of Kd is more readily understood than that of Ka, for example: in considering the conversion of A to AB by the binding of ligand B, the Kd = B when A = AB. Thus Kd is equal to the ligand concentration which produces half maximal conversion (response). (10 Jan 1998) |
| equilibrium dialysis | In immunology, a method for determination of association constants for hapten-antibody reactions in a system in which the hapten (dialyzable) and antibody (nondialyzable) solutions are separated by semipermeable membranes. Since at equilibrium the quantity of free hapten will be the same in the two compartments, quantitative determinations can be made of hapten-bound antibody, free antibody, and free hapten. (05 Mar 2000) |
| equilibrium potential | <physiology> The membrane potential at which a particular type of ion or other particle does not diffuse through the membrane in either direction. (09 Oct 1997) |
| linkage equilibrium | <genetics> Situation that should exist in a population undisturbed by selection, migration, etc., in which all possible combinations of linked genes should be present at equal frequency. The situation is no more common than are such undisturbed populations. (18 Nov 1997) |
| Venereal Disease Research Laboratory | <microbiology> A blood test used to diagnose syphilis. Read as nonreactive or negative if you do not have syphilis. The Venereal Disease Research Laboratory can also be positive is cases of leprosy, malaria, mononucleosis, lupus, hepatitis A and pregnancy. Positive Venereal Disease Research Laboratory tests are usually followed up by a more specific test (FTA antibodies). (12 Jan 1998) |
| Medical Research Council | <organisation> A UK Government funded body to promote the balanced development of medical and related biological research in the United Kingdom. It organises national clinical trials for the assessment of new treatment protocols for leukaemia and some of the related diseases. (05 Jan 1998) |
| research | Careful, a diligent search, a close searching, studious inquiry or examination. (18 Nov 1997) |
| research, controlled | The first controlled clinical research was probably done in 1875 by the british naval surgeon james lind who, on board the hms salisbury, gave sailors with scurvy either oranges or lemons or cider or vinegar or nutmeg (or another treatment) and after just six days discovered that the citrus-consuming sailors had recovered from scury, until then the scourge of extended sea voyages, while the sailors who had been given the other treatments remained uncured. (12 Dec 1998) |
| research design | A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly. (12 Dec 1998) |
| research personnel | Those individuals engaged in research. (12 Dec 1998) |
| research support | Financial support of research activities. (12 Dec 1998) |
| peer review, research | The evaluation by experts of the quality and pertinence of research or research proposals of other experts in the same field. Peer review is used by editors in deciding which submissions warrant publication, by granting agencies to determine which proposals should be funded, and by academic institutions in tenure decisions. (12 Dec 1998) |