(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.
Example Sentences:
(1) The thiol-conjugating capacity of quinones may, however, be applied to reduce the tissue-damaging effects of stimulated neutrophils.
(2) The effect of dicoumarol on glucuronidation of 3-OH-benzo(a)pyrene (BP) appears to be due to inhibition of UDPglucuronosyltransferase (UDPGT) and not to an inhibited DT-diaphorase (NAD(P)H:quinone oxidoreductase); to date the only enzyme known to be inhibited by dicoumarol.
(3) The coupled dienone-phenol re-arrangement and keto-enol tautomerism of this quinone methide produce the observed 3,4-dihydroxybenzaldehyde.
(4) Moreover, it seems unlikely that quinones are involved directly (e.g.
(5) The second-order rate constants appear to be at least 3 orders of magnitude lower than the second-order constants for quenching of the fluorescent probes; this is taken as a clear indication that ubiquinone diffusion is not the rate-determining step in the quinone-enzyme interaction.
(6) 15 human tumour cell lines (lung, breast and colon) have been evaluated for their sensitivity to the quinone based anti-cancer drugs Mitomycin C, Porfiromycin, and EO9 (3-hydroxymethyl-5-aziridinyl-1-methyl-2-(IH-indole-4,7-dione)prop-beta- en-alpha-ol).
(7) These studies provide evidence that GHB exerts cytotoxicity specifically for cells that by their content of tyrosinase convert the phenol to the quinone.
(8) Comparison of these two activities for both the quinone and hydroquinone showed that the hydroquinone form had superior activities.
(9) Bis(alkylthio)quinones 4a-d and 5a-d, and corresponding hydroquinones 9b-d exhibited high activities both in vitro and in vivo.
(10) It seems that quinone pigments, especially 2-oxyjuglone, react with complex I faster than it follows from their approximate values of one-electron reduction potential calculated from their reactivities with flavocychrome b2 and adrenodoxin.
(11) Formation of catechol from quinone by cyst extracts was observed spectrophotometrically and chromatographically.
(12) The present studies were conducted to evaluate the relative effect of the parent chemical BHT and two of its major oxidative metabolites, 2,6-di-tert-butyl-4-hydroxymethylphenol (BHT-BzOH) and 2,6-di-tert-butyl-1,4-benzoquinone (BHT-quinone), on DMBA-induced rat mammary tumorigenesis and on the formation of rat mammary DMBA-DNA adducts in vivo.
(13) Quinones play a major role in allergic contact dermatitis caused by plants.
(14) The urushiol analogs 5-pentadecylresorcinol (PDR) and 3-heptadecylveratrole (HDV) which cannot form o-quinones were found to be ineffective sensitizers as well.
(15) Toxicity of quinone(di)imines to hepatocytes and CHO cells was not related to superoxide anion radical formation, and toxicity to CHO cells was not affected by exclusion of oxygen during exposure of the cells to the compounds.
(16) The activity of cytochrome P-450 reductase, which reduces quinones to hydroquinones in the estrogen redox cycle, was 6-fold higher in liver than in kidney of both control and estrogen-treated animals.
(17) The interaction of pyrroloquinoline quinone (PQQ) with amino groups was followed by measuring the capacity of adducts to reduce nitroblue tetrazolium (NBT).
(18) The menadione-induced quinone reductase was isolated from the cytoplasmic fraction of induced cells.
(19) Hepa 1c1c7 murine hepatoma cells are plated in 96-well microtiter plates, grown for 24 h, and exposed to inducing agents for another 24 h. The cells are then lysed and quinone reductase activity is assayed by the addition of a reaction mixture containing an NADPH-generating system, menadione (2-methyl-1,4-naphthoquinone), and MTT [3-(4,-5-dimethylthiazo-2-yl)-2,5-diphenyltetrazolium bromide].
(20) quinone complex (X) was chemically reduced (state [PIX-]; P is the reaction center bacteriochlorophyll dimer, I is the long wavelength bacteriopheophytin), and compares these with the fluorescence observed when all the traps are open (state [PIX]) and with the fluorescence observed when all the traps are closed (state [P+IX]).
Ring
Definition:
(v. t.) To cause to sound, especially by striking, as a metallic body; as, to ring a bell.
(v. t.) To make (a sound), as by ringing a bell; to sound.
(v. t.) To repeat often, loudly, or earnestly.
(v. i.) To sound, as a bell or other sonorous body, particularly a metallic one.
(v. i.) To practice making music with bells.
(v. i.) To sound loud; to resound; to be filled with a ringing or reverberating sound.
(v. i.) To continue to sound or vibrate; to resound.
(v. i.) To be filled with report or talk; as, the whole town rings with his fame.
(n.) A sound; especially, the sound of vibrating metals; as, the ring of a bell.
(n.) Any loud sound; the sound of numerous voices; a sound continued, repeated, or reverberated.
(n.) A chime, or set of bells harmonically tuned.
(n.) A circle, or a circular line, or anything in the form of a circular line or hoop.
(n.) Specifically, a circular ornament of gold or other precious material worn on the finger, or attached to the ear, the nose, or some other part of the person; as, a wedding ring.
(n.) A circular area in which races are or run or other sports are performed; an arena.
(n.) An inclosed space in which pugilists fight; hence, figuratively, prize fighting.
(n.) A circular group of persons.
(n.) The plane figure included between the circumferences of two concentric circles.
(n.) The solid generated by the revolution of a circle, or other figure, about an exterior straight line (as an axis) lying in the same plane as the circle or other figure.
(n.) An instrument, formerly used for taking the sun's altitude, consisting of a brass ring suspended by a swivel, with a hole at one side through which a solar ray entering indicated the altitude on the graduated inner surface opposite.
(n.) An elastic band partly or wholly encircling the spore cases of ferns. See Illust. of Sporangium.
(n.) A clique; an exclusive combination of persons for a selfish purpose, as to control the market, distribute offices, obtain contracts, etc.
(v. t.) To surround with a ring, or as with a ring; to encircle.
(v. t.) To make a ring around by cutting away the bark; to girdle; as, to ring branches or roots.
(v. t.) To fit with a ring or with rings, as the fingers, or a swine's snout.
(v. i.) To rise in the air spirally.
Example Sentences:
(1) The Tyr side chain had two conformations of comparable energy, one over the ring between the Gln and Asn side chains, and the other with the Tyr side chain away from the ring.
(2) Sterile, pruritic papules and papulopustules that formed annular rings developed on the back of a 58-year-old woman.
(3) The teeth were embedded in phenolic rings with acrylic resin.
(4) Surgical removal was avoided without complications by detaching it with a ring stripper.
(5) The Labour MP urged David Cameron to guarantee that officers who give evidence over the alleged paedophile ring in Westminster will not be prosecuted.
(6) These results coupled with previous studies support activation of benz[j]aceanthrylene via both 2 and cyclopenta ring epoxidation.
(7) TK1 showed the most restricted substrate specificity but tolerated 3'-modifications of the sugar ring and some 5-substitutions of the pyrimidine ring.
(8) Endothelium-dependent relaxations to acetylcholine and endothelium-independent relaxations to nitric oxide were observed in rings from both strains during contraction with endothelin.
(9) Aortic rings from the rabbit were similarly potently antagonized by the protein kinase C inhibitors, however, K(+)-induced contractions were also equally sensitive to these agents in both rat and rabbit tissues.
(10) The intracellular distribution and interaction of 19S ring-type particles from D. melanogaster have been analysed.
(11) Rings of isolated coronary and femoral arteries (without endothelium) were suspended for isometric tension recording in organ chambers filled with modified Krebs-Ringer bicarbonate solution.
(12) In all cases Richter's hernia was at the internal inguinal ring.
(13) Seventy-five hands showed normal distal latency, in which cases, however, the SNCV of the ring finger was always outside the normal range, while the SNCVs of the thumb, index and middle fingers were abnormal in 64%, 80% and 92% of cases respectively.
(14) The cells are predominantly monopolar, tightly packed, and are flattened at the outer border of the ring.
(15) Defects in the posterior one-half of the trachea, up to 5 rings long, were repaired, with minimal stenosis.
(16) A new analog of salmon calcitonin (N alpha-propionyl Di-Ala1,7,des-Leu19 sCT; RG-12851; here termed CTR), which lacks the ring structure of native calcitonin, was tested for biological activity in several in vitro and in vivo assay systems.
(17) The chemical shift changes observed on the binding of trimethoprim to dihydrofolate reductase are interpreted in terms of the ring-current shift contributions from the two aromatic rings of trimethoprim and from that of phenylalanine-30.
(18) Three strains of fluorescent pseudomonads (IS-1, IS-2, and IS-3) isolated from potato underground stems with roots showed in vitro antibiosis against 30 strains of the ring rot bacterium Clavibacter michiganensis subsp.
(19) Both adiphenine.HCl and proadifen.HCl form more stable complexes, suggesting that hydrogen bonding to the carbonyl oxygen by the hydroxyl-group on the rim of the CD ring could be an important contributor to the complexation.
(20) Serial sections from over a hundred such structures show that these are tubular structures and that the 'test-tube and ring-shaped' forms described in the literature are no more than profiles one expects to see when a tubular structure is sectioned.