from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of a class of aromatic compounds found widely in plants, especially the yellow crystalline form, C6H4O2, used in making dyes, tanning hides, and photography.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. any of a class of aromatic compounds having two carbonyl functional groups in the same six-membered ring
from the GNU version of the Collaborative International Dictionary of English
- n. A crystalline substance, C6H4O2 (called also benzoketone), first obtained by the oxidation of quinic acid and regarded as a double ketone; also, by extension, any one of the series of which quinone proper is the type.
from The Century Dictionary and Cyclopedia
- n. The general name applied to all benzene derivatives in which two hydrogen atoms are replaced by two oxygen atoms.
- n. Specifically, a compound obtained by distilling kinic acid with diluted sulphuric acid and peroxid of manganese, or by the oxidation of aniline with chromic acid.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any of a class of aromatic yellow compounds including several that are biologically important as coenzymes or acceptors or vitamins; used in making dyes
Drink tonic water the quinone is a nerve relaxant and try Naphcon A eye drops.
There is now growing evidence that supplementation with a substance that many nutritional scientists believe is a newly discovered vitamin, pyrroloquinoline quinone, or PQQ, may also help reduce the risk of various forms of dementia, including Alzheimer's dementia.
The Zeta crystallin, quinone reductase, found in some mammals is transcribed from a lens specific promoter not present in other mammals.
He had just shown Mummy the letter he had written to Desmond Erb, apologising for correcting him when he wrote about 'the quinone structure'.
The figure shows how the photosynthetically active components bacteriochlorophyll (BK), bacteriopheophytin (BF), quinone
The structure shows the precise arrangement in the L and M subunits of the photochemically active groups – two chlorophyll molecules forming a dimer, two monomeric chlorophylls, two pheophytin molecules (these lack the central magnesium ion of chlorophyll), one quinone molecule, called
In this, as in his later work on quinone and quinone type compounds which are the basis of many dyestuffs, he sought to acquire skill in chemical methods in order to prepare himself for the extensive and more difficult work of investigating plant and animal pigments.
Among these was his work on the electrolysis of solid salts (1904), on the establishment of the quinone-hydroquinone equilibrium at the cathode, which laid the foundations for Biilmann's quinhydrone electrode for determining the acidity of a liquid; but Haber invented, in collaboration with Cremer, the glass electrode for the same purposes which is now widely used.
It may be noted that quinone only effects pseudo-tannage; quinone mixed with water deposits, in time, a black amorphous substance practically insoluble in water.
A spent quinone liquor contains considerable amounts of hydroquinone.