| TTI | tension-time index; time-tension index; timepto-intubation; torque-time interval; transtracheal insu... |
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| AFB | Acid-Fast Bacillus(Type that causes Tuberculosis) |
| AFB Stain | Acid Fast Bacilli Stain |
| FLASH | Fast Low Angle SHot |
| AF | abnormal frequency; acid-fast; adult female; afebrile; aflatoxin; albumin-free; albumose-free; aldeh... |
| dissociation constant of a base | Expressed by the general equation [B+][OH-]/[BOH] = Kb, where BOH is the undissociated base. (05 Mar 2000) |
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| dissociation constant of an acid | Expressed by general equation [H+][A-]/[HA] = Ka, where HA is the undissociated acid. (05 Mar 2000) |
| dissociation constant of water | Expressed by the equation [H+][OH-] = Kw = 10-14 at 25캜. (05 Mar 2000) |
| immunoglobulin constant region | That region of the immunoglobulin (antibody) molecule that is invariable in its amino acid sequence within any class of immunoglobulins. It confers the biological specificity to the ig and is grossly species specific. It comprises the c-terminus half of the light chains and three quarters or more of the heavy chains, all of the fc fragment, and the c-terminus half of the fab fragment. (12 Dec 1998) |
| transformation constant | <physics, radiobiology> The fraction of the amount of a radionuclide that undergoes transition per unit time. Formally: Lamda=dP/dt Where dP is the probability of a given nucleus undergoing spontaneous nuclear transition in the time interval dt. (16 Dec 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) |
| universal gas constant | <radiobiology> R = 8.314 x 10^7 ergs per degree C per mole. (09 Oct 1997) |
| flotation constant | Characteristic sedimentation behaviour of a lipoprotein fraction of plasma in a centrifugal field in a medium of appropriate density, achieved by adding a salt or D2O to the plasma. Synonym: negative S, Svedberg of flotation. (05 Mar 2000) |
| law of constant numbers in ovulation | The number of ova discharged at each ovulation is nearly constant for any given species. (05 Mar 2000) |
| activated clotting time | The most common test used for coagulation time in cardiovascular surgery. (05 Mar 2000) |
| activated partial thromboplastin time | The time needed for plasma to form a fibrin clot following the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system. (05 Mar 2000) |
| A-H conduction time | Forward conduction of the cardiac impulse from atria to ventricles via the A-V node or any bypass tract, represented in the electrocardiogram by the P-R interval. P-H conduction time is from the onset of the P wave to the first high frequency component of the His bundle electrogram (normally 119 ± 38 msec); A-H conduction time is from the onset of the first high frequency component of the atrial electrogram to the first high frequency component of the His bundle electrogram (normally 92 ± 38 msec); P-A conduction time is from the onset of the P wave to the onset of the atrial electrogram (normally 27 ± 18 msec). (05 Mar 2000) |
| association time | Time elasping between a stimulus and the verbalised response to it. (05 Mar 2000) |
| biologic time | The concept that our appreciation of time varies with age and is governed by the neural organization of the individual; it obeys a logarithmic rather than an arithmetic law. (05 Mar 2000) |
| bleeding time | <haematology> A test which measures the time it takes for small blood vessels to close off and bleeding to stop. Abnormal results can be seen in those with congenital or acquired platelet function disorders or thrombocytopenia. (27 Sep 1997) |