| 释义 |
dextro-
combining form of L. dexter, dextra, used in the sense ‘(turning or turned) to the right’, in physical and chemical terms, chiefly having reference to the property possessed by certain substances of causing the plane of a ray of polarized light to rotate to the right. Among these are: a. dextrogyre |ˈdɛkstrəʊdʒaɪə(r)| a. [L. gȳrus, Gr. γῦρος circuit], gyrating or circling to the right. dextroˈgyrate a. [L. gyrāt-us, pa. pple. of gȳrāre to wheel round], characterized by turning the plane of polarization to the right, as a dextrogyrate crystal. dextroˈgyrous a. = dextrogyre. dextro-roˈtation, rotation to the right. dextro-ˈrotatory a., having or producing rotation to the right; dextrogyrous.
b. dextro-ˈcompound, a chemical compound which causes dextro-rotation. dextro-ˈglucose, the ordinary variety of glucose or grape-sugar, dextrose. dextro-raˈcemic, dextro-tarˈtaric acid, the modifications of racemic and tartaric acid which cause dextro-rotation. Hence dextro-racemate, -tartrate, the salts of these.
a.1876Harley Mat. Med. 366 Called mycose, because it is rather less dextrogyre than cane sugar. 1878Foster Phys. ii. i. 197 The solutions of both acids have a dextro-rotatory action on polarized light. 1882Nature XXV. 283 With each electrode, diverging currents produce dextro- and converging ones lævo-rotation. 1883Athenæum 29 Dec. 871/1 The dextrorotatory and optically inactive gums. 1891Lancet 3 Oct. 751 The dextro-rotatory tartaric acid.
b.1853Pharmac. Jrnl. XIII. 111 Pasteur discovered that racemic acid is a compound of two acids, one of which turns the plane of polarization of a ray of light to the right, and the other to the left; he therefore called them Dextro-racemic-acid and Levo-racemic-acid. Ibid. 112 A solution of dextro-racemate of soda and ammonia. Ibid. 377 The dextro-tartrate crystallizes out. 1863–72Watts Dict. Chem. II. 855 Dextro-glucose occurs abundantly in sweet fruits, frequently together with cane sugar. 1873Fownes' Chem. (ed. 11) 731 Dextrotartaric Acid is the acid of fruits. |