| light adaptation | The visual adjustment occurring under increased illumination in which the retinal sensitivity to light is reduced. See: light-adapted eye. Synonym: photopic adaptation. (05 Mar 2000) |
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| light-adapted eye | An eye that has been exposed to light, with bleaching of rhodopsin (visual purple) and insensitivity to low illumination. Synonym: photopic eye. (05 Mar 2000) |
| light bath | Therapeutic exposure of the skin to radiant light. (05 Mar 2000) |
| light cells of thyroid | Cell's present between follicles or interspersed among follicular cell's; they are rich in mitochondria and are believed to be the source of thyrocalcitonin. Synonym: C cell, light cells of thyroid. (05 Mar 2000) |
| light chain | <immunology, protein> The lighter of the two types of polypeptide chains that are found in immunoglobulin and antibody molecules. Also used as a non-specific term for the smaller subunits of several multimeric proteins such as immunoglobulin, myosin, dynein, clathrin. (14 Oct 1997) |
| light chain-related amyloidosis | A form of primary amyloidosis in which the fibrillar amyloid deposits are derived from the amino terminal variable region of the light chains of immunoglobulin; seen in B-lymphocyte and plasma-cells dyscrasias. (05 Mar 2000) |
| light coagulation | The coagulation of tissue by an intense beam of light, including laser (laser coagulation). In the eye it is used in the treatment of retinal detachments, retinal holes, aneurysms, haemorrhages, and malignant and benign neoplasms. (12 Dec 1998) |
| light-cured resin | A resin which uses visible or ultraviolet light to excite a photoinitiator which interacts with an amine to form free radicals and initiate polymerization. Used mainly in restorative dentistry. Synonym: light-activated resin. (05 Mar 2000) |
| light dependent reaction | The reaction taking place in the chloroplast in which the absorption of a photon leads to the formation of ATP and NADPH. (18 Nov 1997) |
| light difference | The difference in light sensitivity of the two eyes. Synonym: brightness difference threshold. (05 Mar 2000) |
| light differential threshold | The smallest difference in light intensity that can be appreciated. (05 Mar 2000) |
| light green SF yellowish | An acid arylmethane dye, used as a cytoplasmic stain in plant and animal histology; fades badly in bright light. (05 Mar 2000) |
| light harvesting system | Set of photosynthetic pigment molecules that absorb light and channel the energy to the photosynthetic reaction centre, where the light reactions of photosynthesis occur. In higher plants, contains chlorophyll and carotenoids and is present in two slightly different forms in photosystems I and II. (18 Nov 1997) |
| light-hearted | Free from grief or anxiety; gay; cheerful; merry. Light-heartedly, Light-heartedness. Source: Websters Dictionary (01 Mar 1998) |
| light-horseman | 1. A soldier who serves in the light horse. 2. <zoology> A West Indian fish of the genus Ephippus, remarkable for its high dorsal fin and brilliant colours. Source: Websters Dictionary (01 Mar 1998) |