(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.
Metal
Definition:
(n.) An elementary substance, as sodium, calcium, or copper, whose oxide or hydroxide has basic rather than acid properties, as contrasted with the nonmetals, or metalloids. No sharp line can be drawn between the metals and nonmetals, and certain elements partake of both acid and basic qualities, as chromium, manganese, bismuth, etc.
(n.) Ore from which a metal is derived; -- so called by miners.
(n.) A mine from which ores are taken.
(n.) The substance of which anything is made; material; hence, constitutional disposition; character; temper.
(n.) Courage; spirit; mettle. See Mettle.
(n.) The broken stone used in macadamizing roads and ballasting railroads.
(n.) The effective power or caliber of guns carried by a vessel of war.
(n.) Glass in a state of fusion.
(n.) The rails of a railroad.
(v. t.) To cover with metal; as, to metal a ship's bottom; to metal a road.
Example Sentences:
(1) In this study of ten consecutive patients sustaining molten metal injuries to the lower extremity who were treated with excision and grafting, treatment with compression Unna paste boot was compared with that with conventional dressing.
(2) The LD50 of the following metal-binding chelating drugs, EDTA, diethylenetriaminepentaacetic acid (DTPA), hydroxyethylenediaminetriacetic acid (HEDTA), cyclohexanediaminotetraacetic acid (CDTA) and triethylenetetraminehexaacetic acid (TTHA) was evaluated in terms of mortality in rats after intraperitoneal administration and was found to be in the order: CDTA greater than EDTA greater than DTPA greater than TTHA greater than HEDTA.
(3) Our recurrences are due to local infections, removing the metal strut too early, i.e.
(4) "Acoustic" craters were produced by two laser pulses delivered into a saline-filled metal fiber cap, which was placed in a mechanically drilled crater.
(5) These results indicate that the inhibition of CarAc by heavy metals occurs by binding of the sulfhydryl on the enzyme by the metals.
(6) The consequences of proved hypersensitivity in patients with metal-to-plastic prostheses, either present prior to insertion of the prosthesis or evoked by the implant material, are not known.
(7) In general, enzyme activity was strongly reduced by heavy metal inorganic cations; less strongly by organometallic cations, some anions, and certain pesticides; and weakly inhibited by light metal cations and organometallic and organic compounds.
(8) EGTA was ineffective in removing calmodulin from particulate preparations, but treatment with the tervalent metal ion La3+ resulted in a loss of up to 98% of calmodulin activity from these preparations.
(9) Sift the cocoa powder over the top and lightly but thoroughly fold it in with the metal spoon.
(10) The results also suggest that both alkali metals most probably have been delivered to the suckling pups and some of their toxic effect was retarded.
(11) The radioprotective action in E. coli ATCC 9637 of ascorbate added to media containing the weak sensitizer, tetracycline (effect described by Pittillo and Lucas (1967)), was found to be dependent on the presence of metal catalysts of the autoxidation of ascorbate.
(12) This study introduces a simple in vitro arrangement to measure current densities of implant metals.
(13) A rubber cuff was fixed on the metal cylinder and let an opening of 8 cm, simulating the cervix uteri.
(14) Since the enzyme requires a metal ion (Co2+) we suggest that the RNA and heparin are inhibitory by virtue of their capacity to chelate the Co2+.
(15) Lesions of allergic contact type could not be induced in the oral mucosa to any of the metal salt preparations.
(16) As yet the observations demonstrate that workers exposed in their occupation to heavy metals (cadmium, lead, metalic mercury) and organic solvents should be subjected to special control for detection of renal changes.
(17) This study investigates the photoneutron field found in medical accelerator rooms with primary barriers constructed of metal slabs plus concrete.
(18) While a clearcut relationship cannot be established between heavy metal music and destructive behavior, evidence shows that such music promotes and supports patterns of drug abuse, promiscuous sexual activity, and violence.
(19) The physiologically important metal ion for catalysis is Mg2+; however, Mn2+ supports in vitro activity, though at a reduced level.
(20) We support the view that catalysis by metalloenzymes may be a reflection of the chemistry of the metal ion itself as a Lewis acid, and that perhaps too much emphasis has been placed on supposed special characteristics (such as strains, "entasis") of the enzyme-metal ion association.