| screen-film contact | The closeness and uniformity with which the X-ray film in a cassette lies against the screen. Image resolution is dependent on this closeness and uniformity of contact. (05 Mar 2000) |
|---|---|
| nonreciprocal contact inhibition | <cell biology> Collision behaviour between different cell types in which one cell shows contact inhibition of locomotion and the other does not. An example is the interaction between sarcoma cells and fibroblasts (the former not being inhibited). (18 Nov 1997) |
| deflective occlusal contact | A condition of tooth contact's which diverts the mandible from a normal path of closure to centric jaw relation. Synonym: cuspal interference, interceptive occlusal contact, premature contact. (05 Mar 2000) |
| dermatitis, allergic contact | A contact dermatitis due to allergic sensitization to various substances. These substances subsequently produce inflammatory reactions in the skin of those who have acquired hypersensitivity to them as a result of prior exposure. (12 Dec 1998) |
| dermatitis, contact | A type of acute or chronic skin reaction in which sensitivity is manifested by reactivity to materials or substances coming in contact with the skin. It may involve allergic or non-allergic mechanisms. (12 Dec 1998) |
| initial contact | The first meeting of opposing teeth upon elevation of the mandible toward the maxillae, the initial occlusal contact of opposing teeth when the jaw is closed. (05 Mar 2000) |
| interceptive occlusal contact | A condition of tooth contact's which diverts the mandible from a normal path of closure to centric jaw relation. Synonym: cuspal interference, interceptive occlusal contact, premature contact. (05 Mar 2000) |
| irritant contact dermatitis | Skin reactions ranging from erythema and scaling to necrotic burns resulting from nonimmunologic damage by chemicals in contact with the skin immediately or repeatedly. (05 Mar 2000) |
| achromatic lens | A compound lens made of two or more lens's having different indices of refraction, so correlated as to minimise chromatic aberration. (05 Mar 2000) |
| acoustic lens | In ultrasonography, a lens used to focus or diverge a sound beam; may be simulated by electronic manipulation of signals. (05 Mar 2000) |
| anterior pole of lens | The central point on the anterior surface of the lens of the eye. Synonym: polus anterior lentis. (05 Mar 2000) |
| anterior surface of lens | The anterior surface of the lens of the eye. Synonym: facies anterior lentis. (05 Mar 2000) |
| aplanatic lens | A lens designed to correct spherical aberration and coma (q.v.). Synonym: periscopic meniscus. (05 Mar 2000) |
| apochromatic lens | A compound lens designed to correct both spherical and chromatic aberrations. (05 Mar 2000) |
| asphenc lens | <physics> A lens made aplanatic by grinding the outer zones to a greater radius than the inner zones. Aplanatic condensers can be made in this way. A simple aspheric lens is widely used as a lamp condenser because of its efficiency in converging light rays to one focal plane. (05 Aug 1998) |