(n.) A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water gas. It is standard of chemical equivalents or combining weights, and also of valence, being the typical monad. Symbol H. Atomic weight 1.
Example Sentences:
(1) The hypothesis that proteins are critical targets in free radical mediated cytolysis was tested using U937 mononuclear phagocytes as targets and iron together with hydrogen peroxide to generate radicals.
(2) It has been conformed that catalase from bovine liver eliminates only the pro R hydrogen atom from ethanol.
(3) We investigated the possible contribution made by oropharyngeal microfloral fermentation of ingested carbohydrate to the generation of the early, transient exhaled breath hydrogen rise seen after carbohydrate ingestion.
(4) Hydrogen isotope effects on these mutants indicate that MotA catalyzes proton transfer.
(5) Excessive accumulation of hydrogen ions in the brain may play a pivotal role in initiating the necrosis seen in infarction and following hyperglycemic augmentation of ischemic brain damage.
(6) Studies were conducted in isolated, buffer-perfused rat lungs to determine if prostaglandin (PG) E1 attenuated pulmonary edema provoked by hydrogen peroxide (H2O2).
(7) All N and O atoms except N(3) and O(4') participate in a three-dimensional hydrogen-bonding system.
(8) 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.
(9) Control mutant S38N has stability essentially the same as that of wild-type lysozyme but hydrogen bonding similar to that of the stabilizing mutant S38D.
(10) High intensity ultrasound also enhances the heterogeneous catalysis of alkene hydrogenation by Ni powders.
(11) An atmosphere of hydrogen eliminates this inhibition in the hydrogenase-containing T. foetus but not in E. invadens which lacks the enzyme.
(12) 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.
(13) Our findings suggest that (a) the inclusion of a liquid meal provides a reproducible method of measuring orocaecal transit using the lactulose hydrogen breath test, (b) rapid small bowel transit in thyrotoxicosis may be one factor in the diarrhoea which is a feature of the disease and (c) if altered gut transit is the cause of sluggish bowel habit in hypothyroidism, delay in the colon, and not small bowel, is likely to be responsible.
(14) Stepwise hydrogenation of metal tetradehydrocorrin salts (10 double bonds) yields a series of macrocycles containing 9, 8, 7, 6 and 5 double bonds and conditions necessary to obtain corrins have been established.
(15) 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.
(16) (7) The first-order radical transformation rates are independent of the (initial) concentration of N3 or peptide and unaffected by urea (as a modifier of hydrogen bond structures).
(17) Intermolecular contacts occur in both oligomers in the minor groove: in the B form through twisted guanine-guanine hydrogen bonding, and in the Z form through base-base stacking and the water network.
(18) Equilibrium-partitioning measurements indicate that the relative affinities of different probes for PC-rich vesicles, in competition with HODMA or DOTAP vesicles, increase with increasing hydrogen-bonding capacity of the probe headgroup in the order PC less than N,N-dimethyl PE less than N-methyl PE less than PE approximately phosphatidyl-2-amino-1-propanol.
(19) When tissue metabolism was irreversibly inhibited by exposure to formaldehyde, hydrogen ion concentration and pCO2 were significantly decreased in the mucosal side of the chamber compared with the viable gall bladder.
(20) Based on the refined atomic coordinates of the tRNAphe in the orthorhombic crystal, on the recent advances in the distance dependence of the ring-current magnetic field effects and on the adopted values for the isolated hydrogen-bonded NH resonances, a computed spectrum consisting of 23 protons was constructed.
Pentyl
Definition:
(n.) The hypothetical radical, C5H11, of pentane and certain of its derivatives. Same as Amyl.
Example Sentences:
(1) Maximum potency was displayed by N-tert-pentyl-N'-3 pyridyl-N"-cyanoguanidine (20).
(2) The other compounds (1-cyclopentylfestuclavine, 13-bromo-1-cyclopropylmethylfestuclavine, 6-cyano-1-propyl-6-norfestuclavine and 6-allyl-1-propyl-6-norfestuclavine) showed mutagenic effects only in the presence of S9, as previously observed with other clavines (agroclavine and its 1-propyl and 1-pentyl derivatives).
(3) In hepatocytes from Aroclor-pretreated rats, 0.09% were pentyl conjugates and 1.1% methyl conjugates.
(4) N-Propyl-, N-butyl, N-isobutyl, and N-pentyl-NNG's were administered to rats as 0.34mM solutions in the drinking water for 12 months and the rats were killed about 6 months later.
(5) Indeed, authentic 4-POBN pentyl radical adduct obtained from the reaction between pentylhydrazine and 4-POBN gave the same mass spectrum as the product obtained from the reaction of linoleic acid and arachidonic acid with 4-POBN.
(6) The ferrochelatase-inhibitory activity of the 4-butyl, 4-pentyl, 4-hexyl, and 4-cyclopropylmethyl analogues of DDC was considered to be due to the formation of the corresponding N-alkylporphyrins.
(7) Determinations of epsilonM of some higher esters (ethyl to pentyl) and some partial methyl esters with one carboxyl group free are also presented.
(8) These compounds were converted to pentyl derivatives with pentyl Grignard reagent and then analysed by C-GC.
(9) Additionally, the ability of the mutant complexes to oxidize reduced benzyl viologen or reduce the ubiquinone analogue 2,3-dimethoxy-5-methyl-6-pentyl-1,4-benzoquinone and phenazine methosulfate with succinate as electron donor were also affected but to varying degrees.
(10) The dog's response magnitude dependence on the nasal flow rate was noticeable for n-pentyl acetates, but not so great as for n-butyric acid.
(11) P450IIB1 also catalyses the alpha-oxygenation of both the pentyl and methyl groups of N-nitrosopentylmethylamine, forming pentaldehyde and formaldehyde at a rate ratio of 2:1, as well as oxygenation at other carbons of the pentyl group.
(12) Finally, in agreement with earlier reports on the naturally occurring pentyl side chain acids, the synthetic acids showed little activity in producing catalepsy in the mouse, suggesting that they would be nonpsychotropic in humans.
(13) The effects of the hypoketonaemic and hypoglycaemic compound 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA) on fatty acid synthesis and fatty acid oxidation in rat hepatocytes were examined.
(14) Phenyl ethyl pentylphosphonate inhibits at least as well or probably better than p-nitrophenyl ethyl pentyl phosphonate, the chemotactic factor induced relase of lysozyme from polymorphonuclear leucocytes spread on Millipore filters in the absence of cytochalasin B.
(15) In the present study, we have investigated agroclavine and its 1-propyl and 1-pentyl derivatives for mutagenicity.
(16) An alpha-fucosidase from the liver of the marine gastropod Charonia lampas was purified to homogeneity using a procedure that included cation-exchange and gel-filtration chromatography, chromatofocusing and a final series of affinity-chromatography steps which involved the following gel-immobilized ligands: N-(5-carboxy-1-pentyl)-1,5-dideoxy-1,5-imino-L-fucitol, N-(5-carboxy-1-pentyl)-2-acetamido-1,5-imino-1,2,5-trideoxy-D-glucitol and thio-beta-D-galactoside.
(17) Systematic examination of a homologous series of omega-aminoalkyl agaroses showed that the pentyl derivative (Seph-C5-NH2) was best suited for the retention and subsequent separation of several proteins involved in the regulation of glutamine metabolism in Escherichia coli, including: glutamine synthetase [EC 6.3.1.2; L-glutamate:ammonia ligase (ADP-forming)], ATP:glutamine synthetase adenylyltransferase (EC 2.7.7.42), the PII regulatory protein which regulates the adenylylation and deadenylylation activities of the adenylyltransferase, the UTP:PII protein uridylyltransferase, and the uridylyl removing enzyme which catalyzes the removal of uridylyl groups from uridylylated PII protein.
(18) The receptor is adsorbed to uncharged pentyl-Sepharose but not to butyl-Sepharose at 1 M NaCl.
(19) The tritiated analogue of R75231 ((+-)-2-(aminocarbonyl)-N-(4-amino-2,6-dichlorophenyl)-4-[5,5-bis (4-fluorophenyl)pentyl]-1-piperazineacetamide) has been examined as a new radioligand for (nitrobenzylthioinosine sensitive) nucleoside transport proteins.
(20) In contrast, for leghemoglobin, although the rate constants decrease from methyl to n-propyl, they show a progressive and important rise with longer alkyl substituents: n-butyl and n-pentyl.