(n.) A colorless nonmetallic element, tasteless and odorless, comprising four fifths of the atmosphere by volume. It is chemically very inert in the free state, and as such is incapable of supporting life (hence the name azote still used by French chemists); but it forms many important compounds, as ammonia, nitric acid, the cyanides, etc, and is a constituent of all organized living tissues, animal or vegetable. Symbol N. Atomic weight 14. It was formerly regarded as a permanent noncondensible gas, but was liquefied in 1877 by Cailletet of Paris, and Pictet of Geneva.
Example Sentences:
(1) These results are discussed in relation to the possible existence of enzyme-bound intermediates of nitrogen fixation.
(2) The measurement of the intestinal metabolism of the nitrogen moiety of glutamic acid has been investigated by oral ingestion of l-[15N]glutamic acid and sampling of arterialized blood.
(3) The induction of cells with two Y chromosomes by nitrogen mustard (NM) was examined.
(4) The disappearance of the herbicide, Avadex (40% diallate), from five agricultural soils (differing in either pH, carbon content, or nitrogen content), incubated under sterile and non-sterile conditions, was followed for a period of 20 weeks.
(5) Suspensions of isolated insect flight muscle thick filaments were embedded in layers of vitreous ice and visualized in the electron microscope under liquid nitrogen conditions.
(6) Airway closure (CV), functional residual capacity (FRC) and the distribution of inspired gas (nitrogen washout delay percentage, NWOD %) and arterial oxygen tension (PaO2) was measured by standard electrodes in eight extremely obese patients before and after weight loss (mean weights 142 and 94 kg, respectively) following intestinal shunt operation.
(7) Formula fed infants retained more nitrogen and gained weight faster.
(8) Triglyceride (Trigly) in female dogs, glutamic-pyruvic transaminase (GPT) and urea nitrogen (Urea-N) in male dogs tended to increase.
(9) Nitrogen retention was curvilinear in relation to metabolic live weight (kg0.75) in both series.
(10) Corynebacterium parvum-treated mice produce large amounts of circulating nitrogen oxides and develop a severe liver injury in response to lipopolysaccharide (LPS).
(11) Eight men and eight women each performed peak oxygen intake tests on a cycle ergometer breathing ambient air and a mixture of 12% oxygen in nitrogen (equivalent to an altitude of 4400 m) in the two experiments.
(12) From this, it was suggested that a negligible amount of oestradiol was released from these compounds and that the oestradiol moiety was useful as a carrier for the nitrogen mustard moiety.
(13) The intravenous administration of ovine placental lactogen to pregnant and non-pregnant sheep produced significant acute decreases in plasma free fatty acid, glucose and amino nitrogen concentrations.
(14) In contrast, nitrogen incubation did not alter the basal levels of TBA reactants except for a small rise associated with VE deficiency.
(15) MCT TPN was found to have some disadvantages, especially with regard to nitrogen balance and plasma albumin levels.
(16) Nitrogen mustard (N2M) treatment of rabbits induced neutropenia, and, in ligated ileal loops, it inhibited fluid secretion induced by salmonella or by cholera toxin (CT).
(17) For dipeptides containing the amino terminal residues glycine, alanine and phenylalanine, abstraction of the hydrogen from the carbon adjacent to the peptide nitrogen was the major process leading to the spin-adducts.
(18) The raw data are obtained by capillary gas chromatography using a nitrogen-phosphorus detector.
(19) Total protein, RNA, DNA, nitrogen, free amino acids and water content were determined in both lymphatic organs.
(20) This is the first evidence supporting carbon-nitrogen bond formation as the initial site of interaction between the two substrate molecules.
Piperidine
Definition:
(n.) An oily liquid alkaloid, C5H11N, having a hot, peppery, ammoniacal odor. It is related to pyridine, and is obtained by the decomposition of piperine.
Example Sentences:
(1) The N-nitrosamines studied were, N-nitroso: dimethylamine, diethylamine, dipropylamine, dibutylamine, pyrrolidine, piperidine, morpholine, methylbenzylamine, bis-(2-hydroxypropyl)amine, bis-(2-oxopropyl)amine and 3,4-dichloropyrrolidine.
(2) In addition, we have found that the dissociative anesthetic N-(1-[2-thienyl]cyclohexyl)3,4-piperidine ([3H]TCP) binds to a site whose regional distribution is highly correlated with that of NMDA receptor sites.
(3) Reduced MPTP (piperidine analog) is inactive in the tissue culture model, while fully oxidized MPTP (pyridinium analog) destroys dopamine neurons.
(4) By use of polyacrylamide sequencing gels the formation of piperidine-labile N7-methylguanine adducts from the reaction of 9 and MNU with 5'-32P-end-labeled DNA restriction fragments is reported.
(5) Drugs of the fentanyl series (4-anilino-piperidines) were potent displacers whereas agonists of the delta- (enkephalin derivatives), sigma- (phencyclidine, haloperidol, 3-hydroxyphenyl-propylpiperidine) or K- (U 50488) opiate sites had a low affinity (Ki greater than 0.5 microM) for 3H-lofentanil specific binding sites.
(6) Piperidine, pyrrolidine, 4-hydroxypiperidine and piperazine at concentrations of 1 microM-30 mM completed dose-dependently with [3H]nicotine and [3H]CD for the binding sites.
(7) It is concluded that the minimum structural requirement for inhibition of alpha-L-fucosidase is the correct configuration of the hydroxy groups at the piperidine ring carbon atoms 2, 3 and 4.
(8) Specific binding was prevented by various dopamine uptake blockers, pyrovalerone, GBR 13069, GBR 12783, N-[1-2-benzo(b)thiophenyl)cyclohexyl] piperidine, cocaine, methylphenidate and was inhibited in a stereoselective manner by the enantiomers of nomifensine.
(9) Chain breaks were induced at the crosslinked sites upon piperidine treatment.
(10) By the aid of enzymatic treatment with calf intestinal phosphatase, the 3'-phosphatase activity of T4-polynucleotide kinase, chemical modification with piperidine in addition to the Maxam-Gilbert sequencing procedure, followed by separation on a DNA-sequencing gel, the nature of the cleaved phosphodiester bond, both 3' and 5' to the cleavage site, has been established.
(11) The ability of the muscarinic receptor antagonists fenipramide, 4-diphenylacetoxy-N-methyl piperidine methiodide (4-DAMP) and secoverine to displace [3H]QNB binding was correlated with the inhibition of responses of cholinomimetics at muscarinic receptors in the atria and ileal longitudinal muscle of the guinea-pig.
(12) In competition studies, the pharmacologic profile of [3H]haloperidol-labeled sigma receptors in human PBL was virtually identical with that in rat cerebellum (slope, 0.87; correlation coefficient, 0.96); the rank order of potency of competing drugs was haloperidol greater than l-butaclamol = pentazocine greater than d-3-(hydroxyphenyl)-N-(1-propyl)-piperidine greater than DTG = d-butaclamol = d-SKF 10,047 greater than levallorphan greater than or equal to PCP greater than or equal to l-SKF 10,047 greater than TCP greater than MK-801.
(13) [3H]N-1-(2-Thienyl)cyclohexyl-3,4-piperidine binding to the phencyclidine site associated with the N-methyl-D-aspartate receptor was reduced by 60-80% in all brain regions examined (P less than 0.001).
(14) Subsequent piperidine hydrolysis produced more frequent breaks of the phosphodiester bonds at guanine positions, thus forming alkali-labile sites.
(15) The binding of [3H]TCP (N-[1-(2-thienyl)cyclo-hexyl]-3,4-piperidine) to the NMDA receptor remained unchanged in all the experimental groups tested.
(16) The postulated active conformation for 1-benzyl-4-[(5,6-dimethoxy-1-oxoindan-2-yl)methyl]piperidine hydrochloride (1a), a potent AChE inhibitor, is close to the crystal structures of 1a with respect to the indanone-piperidine substructure, but differs from the crystal structures for the benzylpiperidine moiety.
(17) Piperidine treatment of the irradiated samples led to specific cleavage of the target with the yield up to 40%.
(18) 65, 499-560) by which aqueous piperidine creates strand breaks at sites of N7-guanine alkylations: alkaline conditions catalyze rupture of the C8-N9 bond, forming a formamido-pyrimidine structure which is displaced from the ribose moiety by piperidine.
(19) Our results show that low energy conformers of the 4-phenyl piperidines have equatorial phenyl rings and cannot completely overlap with rigid opiates at the receptor.
(20) It appears that these piperidine derivatives interfere with the coupling mechanism between acetylcholine-receptor binding and ionic conductance increases.