(n.) An ultimate particle of matter not necessarily indivisible; a molecule.
(n.) A constituent particle of matter, or a molecule supposed to be made up of subordinate particles.
(n.) The smallest particle of matter that can enter into combination; one of the elementary constituents of a molecule.
(n.) Anything extremely small; a particle; a whit.
(v. t.) To reduce to atoms.
Example Sentences:
(1) It has been conformed that catalase from bovine liver eliminates only the pro R hydrogen atom from ethanol.
(2) The results demonstrated that K2PtCl4 was bound to a greater degree than CDDP in this system with 3-5 and 1-2 platinum atoms respectively, bound per transferrin molecule.
(3) Richard Bull Woodbridge, Suffolk • Why does Britain need Chinese money to build a new atomic generator ( Letters , 20 October)?
(4) The bond distances of Cu to Cl(1), Cl(2), N(3) and N(3') atoms are 2.299 (1), 2.267 (1), 1.985 (4) and 1.996 (3) A, respectively.
(5) The common atoms of the [3Fe-4S] and [4Fe-4S] cores agree within 0.1 A; the three common cysteinyl S gamma ligand atoms agree within 0.25 A.
(6) This result was confirmed by atomic absorption spectroscopy, which indicated a stoicheiometry for copper and manganese of approx.
(7) The inter-molecular similarity measure used is the number of atoms in the 3-D common substructure (CS) between the two molecules which are being compared.
(8) The risks are determined, mainly by expert committees, from the steadily growing information on exposed human populations, especially the survivors of the atomic bombs dropped in Japan in 1945.
(9) All N and O atoms except N(3) and O(4') participate in a three-dimensional hydrogen-bonding system.
(10) This suggestion is supported by EPR studies, which show that the iron atoms in Fe(III)L-globin are in two low electronic states.
(11) The molar refractivity has been shown to be a superior parameter for the description of the activity of sulphonamides than the sum of electronegativities of atoms making up a heterocyclic substituent in the sulphonamide molecule and molecular weight of the substituent.
(12) Binding to HSA occurs primarily with the imidazolidine and thiazolidine groups of levamisole as it has been demonstrated by selective changes in the relaxation times and the chemical shifts of the protons attached to the carbon atoms.
(13) Each repeat unit contains thirty amino acids and is thought to bind a zinc atom using two cysteines and two histidines as ligands.
(14) NADP+ bound at the C8 atom in the adenine moiety proved to be the most efficient ligand whereas that bound at the C3 atom of the ribose moiety was relatively inefficient.
(15) This structure is further characterized by approaches of both the carbonyl and the furan O atoms to ring H atoms with separations which are slightly less than the sum of the relevant van der Waals radii.
(16) The magnitude of improvement achieved is dependent upon field size, SSD, the atomic number of the foil material, and foil thickness.
(17) For the liver enzyme, the logarithm of the inhibition constant was linearly related to the number of carbon atoms in the saturated fatty acids whereas the muscle enzyme, which was generally more strongly inhibited, showed a nonlinear dependence.
(18) Results obtained from a such study are here compared with levels obtained from a comparative determination of the metals in the mosses by three other techniques: Differential pulse anodic stripping voltammetry (DPASV), Direct current plasma (atomic emission) spectroscopy (DCPS) and X-ray fluorescence (XRF) spectroscopy.
(19) It was hypothesized that the observed activity variation of the paracetamol analogues was based on the relative abilities of these compounds to undergo H atom loss at the phenolic oxygen, and on the relative stabilities of the resulting free-radical species.
(20) The resulting family of structures has a mean backbone rmsd of 0.63 A (N, C alpha, C', O atoms), excluding the segments containing residues 45-59 and 84-88.
Pyridine
Definition:
(n.) A nitrogenous base, C5H5N, obtained from the distillation of bone oil or coal tar, and by the decomposition of certain alkaloids, as a colorless liquid with a peculiar pungent odor. It is the nucleus of a large number of organic substances, among which several vegetable alkaloids, as nicotine and certain of the ptomaines, may be mentioned. See Lutidine.
Example Sentences:
(1) The 1-0-methylalduronic-acidmethylesters, obtained by the methanolysis of the polysaccharides, are reduced with boronhydrid to the corresponding methyl glycosides; there are split with acid to the aldoses, which are converted in pyridine with hydroxylamine to the aldoximes and than with acetic anhydride to the aldonitrilacetates, which can be separated by gaschromatography without difficulty.
(2) 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.
(3) In both cases, the intensity of cleavage was modulated by the position and the degree of methylation on the pyridinic ring, and results were correlated with cytotoxic activity expressed as the in vitro ID50 values for L1210 leukemia cells.
(4) After an appropriate dilution, the released pyridine-2-thione which has a strong absorbance at 343 nm, is quantified by reading its absorbance in a spectrophotometer at 343 nm.
(5) Oxidation of mitochondrial pyridine nucleotides by alloxan is not mediated by glutathione peroxidase and glutathione reductase and may occur largely nonenzymatically.
(6) The safety and diuretic activity of torasemide (1-isopropyl-3- ([4-(3-methyl-phenylamino)pyridine]-3-sulfonyl)urea) were investigated in a phase I single-blind clinical study.
(7) The non-carcinogens chosen were 4-nitro-o-phenylenediamine, p-phenylenediamine dihydrochloride, 3-nitropropionic acid, dichlorvos, 2-(chloromethyl)pyridine, N-(1-naphthyl)ethylenediamine 2HCl, O-anthranilic acid, 4-nitroanthranilic acid, anilazine and triphenyltin hydroxide.
(8) The alga may be defective in a regulatory mechanism that controls the reoxidation of reduced pyridine nucleotides formed during photosynthesis.
(9) Hydrolysis was inhibited competitively by all pyridine nucleotides when the concentration of Mg [gamma 32P]-ATP was varied between 0.1 mM to 3 mM, but NAD+ was less effective.
(10) Following derivatization with 50 microliters of N-methyl-N-trimethylsilyl trifluoroacetamide-pyridine (1:1) for 20 min at 65 degrees C the samples are analyzed by capillary column gas chromatography-mass spectrometry with selected-ion monitoring.
(11) For each regimen the capsule dose was administered every 8 hours (q 8 h) for 3 days and the plasma profiles of nicardipine and its pyridine analogue (M5) were determined following the last dose on day 4.
(12) Its effects were compared with those of its parent substance CGP 18 137A (2-hydrazino-5-n-butyl-pyridine) which is a general arteriolar dilator.
(13) Reaction of (9) with phosphorus oxychloride in pyridine afforded the desired 6-cyano dienone (4) in 70% yield.
(14) Serial dilutions of pyridine in water are employed for measuring the olfactory detection thresholds of patients.
(15) We have studied the binding of the enzymatically active NAD+ analogue, 3-iodopyridine-adenine dinucleotide, and the inactive analogue, pyridine-adenine dinucleotide to the enzyme horse liver alcohol dehydrogenase using X-ray crystallographic methods.
(16) Computer simulation of spectra using angle selected techniques enabled the assignment of parameters describing the hyperfine and quadrupole interactions for axially bound nitrogen of imidazole in MbOH, of axial pyridine and butylamine in the models, and for the porphyrin nitrogens of the heme in native MbOH.
(17) Since the initial reaction involves internal nucleophilic attack by the pyridine nitrogen, control of the pyridine pKa is critical.
(18) Time-course experiments did not indicate any delay in the peak micronucleus response to benzene caused by either pyridine or xylene.
(19) Similar effects were obtained with local application of 2 microliters of 10(-3) M 4-amino-pyridine to the stimulated cortex.
(20) Based on the analysis of Quantitative Structure--Activity Relationships (QSAR) three representatives of imidazo[4,5-b]pyridine derivatives of predicted high antibacterial activity against Mycobacterium tuberculosis were synthetized and tested bacteriologically.