| AC-DC, ac/dc | alternating current or direct current |
|---|---|
| bili T&D | bilirubin total and direct |
| DA | dark adaptation; dark agouti [rat]; daunomycin; degenerative arthritis; delayed action; Dental Assis... |
| DAGT | direct antiglobulin test |
| DAP | data acquisition processor; depolarizing afterpotential; diabetes-associated peptide; diaminopimelic... |
| focal illumination | Illumination in which a beam of light is directed diagonally to an object so that it is brilliantly illuminated while the surrounding area is in shadow. Synonym: lateral illumination, oblique illumination. Kohler illumination, a method of illumination of microscopic objects in which the image of the light source is focused on the substage condenser diaphragm and the diaphragm of the light source is focused in the same plane with the object to be observed; maximises both the brightness and uniformity of the illuminated field. (05 Mar 2000) |
|---|---|
| lateral illumination | Illumination in which a beam of light is directed diagonally to an object so that it is brilliantly illuminated while the surrounding area is in shadow. Synonym: lateral illumination, oblique illumination. Kohler illumination, a method of illumination of microscopic objects in which the image of the light source is focused on the substage condenser diaphragm and the diaphragm of the light source is focused in the same plane with the object to be observed; maximises both the brightness and uniformity of the illuminated field. (05 Mar 2000) |
| non-direct transmission | <epidemiology> A mode of transmission that differs in some mysterious way from indirect transmission. (05 Dec 1998) |
| direct | 1. Straight, in a straight line. 2. Performed immediately and without the intervention of subsidiary means. Origin: L. Directus (18 Nov 1997) |
| direct acrylic restoration | A direct resin restoration of autopolymerizing acrylic. (05 Mar 2000) |
| direct agglutination | A general term for techniques which use the agglutination (macroscopic clumping) of particulate reagents as an indicator of the presence of an antigen-antibody reaction. Examples (haemagglutination, latex agglutination and coagglutination) follow. (05 Mar 2000) |
| direct B-cell | Lymphocytes responding to a small range of antigens by antibody production without any requirement for T-cells. The antigens include flagellin and pokeweed mitogen. (18 Nov 1997) |
| direct bilirubin | Conjugated bilirubin = Direct bilirubin. Bilirubin that has been chemically attached to a glucuronide in the liver. The bilirubin that is excreted into the bile by the liver and stored in the gallbladder or transferred to the duodenum. Normal direct bilirubin is 0 to 0.3 mg/dl. Greater than normal values can be seen in bile duct obstruction, cirrhosis, Crigler-Najjar syndrome, Dubin-Johnson syndrome and hepatitis. (27 Sep 1997) |
| direct bone impression | An impression of denuded bone, used in the construction of subperiosteal denture implants. (05 Mar 2000) |
| direct composite resin restoration | A direct restoration made by inserting a plastic mix of auto or light-polymerised resins in a cavity prepared in a tooth. Synonym: direct composite resin restoration. (05 Mar 2000) |
| direct contamination | <dentistry> Direct contact with impurities or germs. (for example by a patient sneezing on the assistant.) (08 Jan 1998) |
| direct Coombs' test | A test for detecting sensitised erythrocytes in erythroblastosis foetalis and in cases of acquired immune haemolytic anaemia: the patient's erythrocytes are washed with saline to remove serum and unattached antibody protein, then incubated with Coombs' anti-human globulin (usually serum from a rabbit or goat previously immunised with human globulin); after incubation, the system is centrifuged and examined for agglutination, which indicates the presence of so-called incomplete or univalent antibodies on the surface of the erythrocytes. (05 Mar 2000) |
| direct current | (DC) Electric current which travels continuously in the same direction over a sustained period of time, contrast with AC (Alternating Current) which oscillates as a function of time. (09 Oct 1997) |
| direct diuretic | A diuretic whose primary effect is on renal tubular function. (05 Mar 2000) |
| direct drive | <radiobiology> An approach to inertial-confinement fusion in which the energy of the driver (laser or particle beam) is directly incident on the (usually spherical) target, causing compression heating via ablation of the target surface. (09 Oct 1997) |