(n.) A nitrogenous base, C5H5N, obtained from the distillation of bone oil or coal tar, and by the decomposition of certain alkaloids, as a colorless liquid with a peculiar pungent odor. It is the nucleus of a large number of organic substances, among which several vegetable alkaloids, as nicotine and certain of the ptomaines, may be mentioned. See Lutidine.
Example Sentences:
(1) The 1-0-methylalduronic-acidmethylesters, obtained by the methanolysis of the polysaccharides, are reduced with boronhydrid to the corresponding methyl glycosides; there are split with acid to the aldoses, which are converted in pyridine with hydroxylamine to the aldoximes and than with acetic anhydride to the aldonitrilacetates, which can be separated by gaschromatography without difficulty.
(2) Vanadate-dependent oxidation of either pyridine nucleotide was inhibited by the addition of either superoxide dismutase or catalase, indicating that both superoxide and hydrogen peroxide may be intermediates in the process.
(3) In both cases, the intensity of cleavage was modulated by the position and the degree of methylation on the pyridinic ring, and results were correlated with cytotoxic activity expressed as the in vitro ID50 values for L1210 leukemia cells.
(4) After an appropriate dilution, the released pyridine-2-thione which has a strong absorbance at 343 nm, is quantified by reading its absorbance in a spectrophotometer at 343 nm.
(5) Oxidation of mitochondrial pyridine nucleotides by alloxan is not mediated by glutathione peroxidase and glutathione reductase and may occur largely nonenzymatically.
(6) The safety and diuretic activity of torasemide (1-isopropyl-3- ([4-(3-methyl-phenylamino)pyridine]-3-sulfonyl)urea) were investigated in a phase I single-blind clinical study.
(7) The non-carcinogens chosen were 4-nitro-o-phenylenediamine, p-phenylenediamine dihydrochloride, 3-nitropropionic acid, dichlorvos, 2-(chloromethyl)pyridine, N-(1-naphthyl)ethylenediamine 2HCl, O-anthranilic acid, 4-nitroanthranilic acid, anilazine and triphenyltin hydroxide.
(8) The alga may be defective in a regulatory mechanism that controls the reoxidation of reduced pyridine nucleotides formed during photosynthesis.
(9) Hydrolysis was inhibited competitively by all pyridine nucleotides when the concentration of Mg [gamma 32P]-ATP was varied between 0.1 mM to 3 mM, but NAD+ was less effective.
(10) Following derivatization with 50 microliters of N-methyl-N-trimethylsilyl trifluoroacetamide-pyridine (1:1) for 20 min at 65 degrees C the samples are analyzed by capillary column gas chromatography-mass spectrometry with selected-ion monitoring.
(11) For each regimen the capsule dose was administered every 8 hours (q 8 h) for 3 days and the plasma profiles of nicardipine and its pyridine analogue (M5) were determined following the last dose on day 4.
(12) Its effects were compared with those of its parent substance CGP 18 137A (2-hydrazino-5-n-butyl-pyridine) which is a general arteriolar dilator.
(13) Reaction of (9) with phosphorus oxychloride in pyridine afforded the desired 6-cyano dienone (4) in 70% yield.
(14) Serial dilutions of pyridine in water are employed for measuring the olfactory detection thresholds of patients.
(15) We have studied the binding of the enzymatically active NAD+ analogue, 3-iodopyridine-adenine dinucleotide, and the inactive analogue, pyridine-adenine dinucleotide to the enzyme horse liver alcohol dehydrogenase using X-ray crystallographic methods.
(16) Computer simulation of spectra using angle selected techniques enabled the assignment of parameters describing the hyperfine and quadrupole interactions for axially bound nitrogen of imidazole in MbOH, of axial pyridine and butylamine in the models, and for the porphyrin nitrogens of the heme in native MbOH.
(17) Since the initial reaction involves internal nucleophilic attack by the pyridine nitrogen, control of the pyridine pKa is critical.
(18) Time-course experiments did not indicate any delay in the peak micronucleus response to benzene caused by either pyridine or xylene.
(19) Similar effects were obtained with local application of 2 microliters of 10(-3) M 4-amino-pyridine to the stimulated cortex.
(20) Based on the analysis of Quantitative Structure--Activity Relationships (QSAR) three representatives of imidazo[4,5-b]pyridine derivatives of predicted high antibacterial activity against Mycobacterium tuberculosis were synthetized and tested bacteriologically.
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.