| dark-ground illumination | dark-field illumination |
|---|---|
| dark reaction | <biochemistry, plant biology> The reactions in photosynthesis that occur after NADPH and ATP production and that take place in the stroma of the chloroplast. By means of the reaction, carbon dioxide is incorporated into carbohydrate. (18 Nov 1997) |
| dark t2 lesion | <radiology> (short T2), acute haemorrhage (deoxyHb), haemosiderin, physiologic iron (basal ganglia, etc.), mucinous lesions (?) most abnormalities have long T1 and T2 (dark/bright). Compare: bright T1 lesion. (07 Mar 2000) |
| 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) |