| acrylic | <dentistry> A plastic used to false teeth, retainers, and other dental products. Dental acrylic has been tested and thought to be perfectly safe. (08 Jan 1998) |
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| acrylic acids | A series of unsaturated aliphatic acids of the general formula R==CH-COOH; the prototype, acrylic acid (R=CH2) or 2-propenoic acid, is derived from propionic acid by reduction or from glycerol by dehydration. Synonym: acroleic acids. (05 Mar 2000) |
| acrylic resin | A general term applied to a resinous material of the various esters of acrylic acid; used as a denture base material, for other dental restorations, and for trays. (05 Mar 2000) |
| acrylic resin base | A form made of acrylic resin molded to conform to the tissues of the alveolar process and used to support the teeth of a prosthesis. (05 Mar 2000) |
| acrylic resin tooth | A tooth made of acrylic resin. (05 Mar 2000) |
| direct acrylic restoration | A direct resin restoration of autopolymerizing acrylic. (05 Mar 2000) |
| 3-(2,4--dioxo-6-methyl-5-pyrimidinyl)acrylic acid synthase | <enzyme> Involved in sparsomycin biosynthesis; catalyses conversion of 3-(4-oxo-6-methyl-5-pyrimidinyl)acrylic acid to 3-(2,4-dioxo-6-methyl-5-pyrimidinyl)acrylic acid Registry number: EC 1.14.13.- Synonym: (e)-uca synthase (26 Jun 1999) |
| 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) |
| aspheric lens | A lens with a paraboloidal surface that eliminates spherical aberration. (05 Mar 2000) |