| 释义 |
lævo-, levo-|ˈliːvəʊ|
used as combining form of L. lævus, in the sense ‘(turning or turned) to the left’, 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 left (cf. dextro-). Among these are: a. lævoˈgyrate, lævoˈgyrous adjs., characterized by turning the plane of polarization to the left. lævo-roˈtation, rotation to the left. lævo-ˈrotatory a., = lævogyrate. b. lævo-ˈcompound, a chemical compound which causes lævo-rotation. lævo-ˈglucose = lævulose. lævo-raˈcemic, lævo-tarˈtaric acid, the modifications of racemic and tartaric acid which are lævo-rotatory. Hence lævo-ˈracemate, -ˈtartrate, the salts of these.
a1856Haydn (Cent. s.v. Levogyrate), If the analyser has to be turned from right to left to obtain the natural order of colours, the quartz is called left-handed or *levogyrate. 1853*Levoracemic acid [see dextro- b].
1882Nature XXV. 283 With each electrode, diverging currents produce dextro- and converging ones *lævo-rotation.
1873Fownes' Chem. (ed. 11) 779 Both are *levorotatory. 1897Allbutt's Syst. Med. III. 216 When the urine is lævo-rotatory after trituration with Fehling.
1876tr. Schützenberger's Ferment. 6 Paratartaric acid easily splits up..into dextro-tartaric and *lævo-tartaric acid. |