(n.) Any one of several isometric hydrocarbons, C7H16, of the paraffin series (nine are possible, four are known); -- so called because the molecule has seven carbon atoms. Specifically, a colorless liquid, found as a constituent of petroleum, in the tar oil of cannel coal, etc.
Example Sentences:
(1) The transport of two amino acid analogues, alpha-aminoisobutyric acid and 2-aminobicyclo [2,2,1]-heptane-2-carboxylic acid, which differ in their mode of uptake, was also measured following induction by DMSO.
(2) This technique includes extraction, purification using the solvents n-heptane and 0.5 M Na2CO3, and methylation by 0.1 M HCl-methanol.
(3) High concentrations of leucine or its non-metabolizable analogue, 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH), stimulated insulin release into the culture medium but did not preserve glucose-stimulated insulin release.
(4) Extractions by the Twisselmann method give increasing yields in the order n-pentane, hexane, and n-heptane.
(5) Mobile phases found useful were combinations of 2-propanol and n-heptane.
(6) Consistent with the FDA guidelines in effect at the time of this study, testing was performed with five FSL (water, 3% acetic acid, 8% and 50% ethanol, and n-heptane) at 49 degrees C. Detailed comparisons were made between the migrations to foods and to FSL; following are the more relevant conclusions.
(7) 2-Amino bicyclo-(2,2,1)-heptane-2-carboxylic acid produces a remarkable inhibition of the rate of L-Tyr uptake, but alpha-methylaminoisobutyric acid does not affect the rate of transport of this amino acid.
(8) The addition of the ion-pairing reagent heptane sulfonate was shown to be necessary to achieve separation of all of these bases.
(9) The analysis, in which mercaptopurine and the internal standard, 6-methylthio-2-hydroxypurine, are chromatographed as ion-pairs with heptane-sulfonic acid, employs a simple and rapid sample preparation based on deproteination using 60% trichloroacetic acid.
(10) The recovery of rodent hairs from chocolate has been significantly improved by the introduction of an additional defatting step, substitution of 40% isopropanol for water, and substitution of mineral oil-heptane (85+15) for heptane in the trapping-off step.
(11) This may be attributable to its relatively low partition coefficient (6.1 in n-heptane).
(12) This transport was preferentially inhibited by the system L specific analogue, 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid, the system T substrate tryptophan, and the sulphur homologue of tyrosine, 4-S-cysteinylphenol.
(13) The color reaction which is specific for estrogens is formed by shaking an aliquot of the heptane eluate of mestranol with a 30% methanol-sulfuric acid solution.
(14) 2-[Bicyclo(2,2,1)heptane-2-endo-3-endo-dicarboximido]-glutarimide (taglutimide, K-2004) proved to be a new sedative-hypnotic drug which did not produce any toxic effects when administered orally to mice even at a very high dosage.
(15) Infrared and NMR measurements on solutions of lithium and cesium dinonylnaphtalene sulfonates (DNNS-salts) in heptane show that the state of water in these systems is in several respects similar to its state in solid ion exchange resins and in some respects also similar to that in ordinary water.
(16) Radioligand binding affinities of four new muscarinic antagonists and six potential muscarinic agonists which possess the 2-alkyl-2-azabicyclo[2.2.1]heptane ring system have been determined in rat heart, rat brain, and m1- or m3-transfected CHO cell membrane preparations to examine the selectivity for subtypes of muscarinic receptor.
(17) A simple and convenient chromatographic method is described for the simultaneous and complete separation of the unconjugated steroids progesterone, deoxycorticosterone and 17 alpha-hydroxyprogesterone on 40-cm columns of Sephadex LH-20 using a water-saturated solvent system containing n-heptane-chloroform (1:1) plus 0.25% of ethanol.
(18) alpha Terpineol was recovered from equine tissues by extraction into heptane and detected by gas chromatography, using either flame ionization detection or pentafluoropropionic anhydride derivatization and electron capture detection.
(19) DU-6859, (-)-7-[(7S)-amino-5-azaspiro(2,4)heptan-5-yl]-8-chloro-6- fluoro-1-[(1R,2R)-cis-2-fluoro-1-cyclopropyl]-1,4-dihydro-4-oxoquinol one-3- carboxylic acid, is a new fluoroquinolone with antibacterial activity which is significantly better than those of currently available quinolones.
(20) Stomach and intestine contents and blood samples from guinea-pigs were cleaned up by use of a kieselguhr column followed by heptane-water partition.
Isomer
Definition:
(n.) A body or compound which is isomeric with another body or compound; a member of an isomeric series.
Example Sentences:
(1) An unsaturated fatty acid auxotroph of Escherichia coli was grown with a series of cis-octadecenoate isomers in which the location of the double bond varied from positions 3 to 17.
(2) Fluorination with [18F]acetylhypofluorite yields 6-[18F]fluoro-L-dopa with 95% radiochemical purity; fluorination of the same substrate with [18F]F2 yields a mixture of all three structural isomers in a ratio of 70:16:14 for 6-, 5-, and 2-fluoro compounds.
(3) The cis isomer was retained longer in liver, particularly in mitochondria, but had low retention in that portion of the endoplasmic reticulum isolated as the rough membrane fraction.
(4) The purity and configuration of each isomer of the free acid and N-chloroacetylated derivative were ascertained by: (a) paper chromatography in five solvent systems, (b) elemental analysis, (c) Van Slyke nitrous acid determination of alpha-carbonyl carbon, and (d) Van Slyke ninhydrin determination of alpha-carbonyl carbon, and (e) optical rotation.
(5) The stronger negative potentials may weaken electrostatic receptor interactions and, thereby, cause the trans(E)-isomers to be less active than cis(Z)-isomers.
(6) The identity of each of the three forms was determined by carboxymethylation of the free cysteines in each isomer with [3H]iodoacetic acid followed by determination of the labelled cysteines by tryptic peptide mapping.
(7) In contrast to the enantiomeric discrimination observed with racemic amine, the individual isomers were metabolized at approximately the same rate.
(8) To further assess different binding behavior of these two isomers, association rate was measured.
(9) None of the 3 beta- or 5 beta-isomers had any effect.
(10) Isomers and epimers of glucose influence insulin and cAMP in a parallel fashion as do sulfonylurea compounds (tolbutamide and glibenclamide).
(11) Bioaccumulation experiments were performed on the hexachlorocyclohexane isomers alpha-HCH, beta-HCH, gamma-HCH and delta-HCH, testing them simultaneously.
(12) Although serum total LDH activity was not altered, the LD5 isoenzyme was proportionately higher in the HCH isomers treated animals.
(13) Racemic verapamil and the L- and D-isomer increased cellular vincristine accumulation to the same extent.
(14) The hypothesis that opiate agonism requires an N substituent in the axial position does not appear to be consistent with the increased potency of beta isomers in which axial N substituents are thermodynamically more unstable.
(15) In the case of adducts with the diol-epoxides of benzo[c]phenanthrene, the energetically most favored structures are isomers with significant biological activity.
(16) Liver regeneration was stimulated in male rats with two-thirds of the liver removed by feeding a basal diet supplemented with acetaminophen (0.35-1.5%; weight basis), 2-acetamidophenol (1.0%) and acetophenetidin (1.0%) over a period of 10 days po, but was in the control range with the m-isomer, 3-acetamidophenol (1.0%), N-butyryl-p-aminophenol (1.0%), o-, m- and p-aminophenols (0.50%) and 4-acetamidothiophenol.
(17) However, exposure of the cells to either of the two isomers of azoxy-procarbazine led to significant DNA damage and cytotoxicity.
(18) 1"-Oxobufuralol (3) was reduced with a complex of (2S)-(-)-2-amino-3-methyl-1,1-diphenylbutan-1-ol and borane, yielding 2, which had a 95:5 ratio of the possible 1"R and 1"S isomers as determined by HPLC.
(19) As the two signals had the same intensities, it was suggested that equivalent amounts of cis and trans isomers of the alkenylmether were formed.
(20) The most important recent work has concerned the different anticoagulant potencies and metabolic pathways of the optical isomers of some of these drugs.