(n.) A carbonate in which but half the hydrogen of the acid is replaced by a positive element or radical, thus making the proportion of the acid to the positive or basic portion twice what it is in the normal carbonates; an acid carbonate; -- sometimes called supercarbonate.
Example Sentences:
(1) To examine the central nervous system regulation of duodenal bicarbonate secretion, an animal model was developed that allowed cerebroventricular and intravenous injections as well as collection of duodenal perfusates in awake, freely moving rats.
(2) In addition to esophageal manometry, we also performed acid-clearance studies and examined salivary output, acid-neutralizing capacity, and bicarbonate concentration.
(3) Finally, it could be observed that elevated osmotic pressures reduced the lysis of isolated secretory granules when bicarbonate ions were present in the incubation medium.
(4) In vitro studies in cardiac Purkinje fibers suggested that reversal of amitriptyline-induced cardiac membrane effects by sodium bicarbonate may be attributed not only to alkalinization but also to increased in extracellular sodium concentration, diminishing the local anesthetic action of amitriptyline and resulting in less sodium channel block.
(5) In conclusion, the ability of distal tubules to establish a significant pH gradient will contribute to the titration of non bicarbonate buffers, i.e., to titratable acid formation.
(6) Increasing the pH of local anesthetics with sodium bicarbonate has been reported to hasten their onset of action.
(7) 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.
(8) The addition of sodium bicarbonate to gum containing sorbitol markedly enhanced its capacity to cause and maintain an elevation of interproximal plaque pH previously lowered by exposure to fermentable carbohydrate.
(9) Por the treatment of L.A., adjunction of dialysis and furosemide improved the efficacy of early and massive sodium bicarbonate infusion.
(10) The relationship between urine pH, modified by the oral administration of either ammonium chloride or sodium bicarbonate, and the urinary excretion of prostaglandin E (PGE) was studied in healthy female subjects.
(11) It is suggested that the limited renal capacity to reabsorb sodium may account for the low bicarbonate threshold in premature infants.
(12) The most substantial deviations between actual and theoretical osmolarity values occurred with the calcium chloride, sodium bicarbonate, potassium chloride and dextrose solutions.
(13) Outward Na+ cotransport fluxes significantly rose (p less than 0.05) after acetate hemodialysis and decreased (p less than 0.05) after bicarbonate hemodialysis.
(14) The results demonstrate that: (1) the administration of somatostatin at a low dose level does not affect human exocrine pancreatic secretion, at least under the experimental conditions of this study; and (2) the administration of larger doses of somatostatin inhibits pancreatic secretion of both protein and bicarbonate dose-dependently.
(15) It is suggested from these in vivo studies that renal carbonic anhydrase is present and active during fetal life and does not limit the capacity of the fetal kidney to reabsorb bicarbonate.
(16) These data demonstrate that PTH induces bicarbonate and phosphate excretion regardless of whether carbonic anhydrase is intact or nearly 100% inhibited by acetazolamide.
(17) We therefore investigated the influence of different carbon dioxide tensions and bicarbonate concentrations on directly measured pH of organ baths aerated with mass-spectrometric analyzed O2-CO2 gases.
(18) Bicarbonate administration by either route resulted in an elevated mixed venous partial pressure of carbon dioxide and an elevated arterial pH, but no significant change in the arterial partial pressure of carbon dioxide.
(19) More recently, attention has also been focussed on bicarbonate transport in attempts to identify a possible role for this ion in enhancing the rate of net fluid efflux by proximal tubules.
(20) VO2+ is more effective than Mg2+ in activation of the bicarbonate-dependent ATPase reaction of pyruvate kinase, and in the enzyme-catalyzed hydrolysis of phosphoenolpyruvate.
Hydrogen
Definition:
(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.