(n.) An elementary substance, not metallic in its nature, which is present in all organic compounds. Atomic weight 11.97. Symbol C. it is combustible, and forms the base of lampblack and charcoal, and enters largely into mineral coals. In its pure crystallized state it constitutes the diamond, the hardest of known substances, occuring in monometric crystals like the octahedron, etc. Another modification is graphite, or blacklead, and in this it is soft, and occurs in hexagonal prisms or tables. When united with oxygen it forms carbon dioxide, commonly called carbonic acid, or carbonic oxide, according to the proportions of the oxygen; when united with hydrogen, it forms various compounds called hydrocarbons. Compare Diamond, and Graphite.
Example Sentences:
(1) Carbon dioxide (CO2) levels, volumes, and temperatures of expired gas were measured from the tracheal and esophageal tubes.
(2) Biochemical, immunocytochemical and histochemical methods were used to study the effect of chronic acetazolamide treatment on carbonic anhydrase (CA) isoenzymes in the rat kidney.
(3) To quantify the size of the lesion in mice, the area of the infarct on the brain surface was assessed planimetrically 48 h after MCA occlusion by transcardial perfusion of carbon black.
(4) Ethanol and L-ethionine induce acute steatosis without necrosis, whereas azaserine, carbon tetrachloride, and D-galactosamine are known to produce steatosis with varying degrees of hepatic necrosis.
(5) Heart rate (HR), pulmonary ventilation (V), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory quotient (RQ) were measured.
(6) Given Australia’s number one position as the worst carbon emitter per capita among major western nations it seems hardly surprising that islanders from Fiji, Samoa, Vanuatu and other small island developing states have been turning to Australia with growing exasperation demanding the country demonstrate an appropriate response and responsibility.
(7) 4) Parents imagined that fruit drinks, carbonated beverages and beverages with lactic acid promoted tooth decay.
(8) This capacity is expressed during incubation of the bacteria with the substrate and needs a source of carbon and other energy metabolites.
(9) The disappearance of the herbicide, Avadex (40% diallate), from five agricultural soils (differing in either pH, carbon content, or nitrogen content), incubated under sterile and non-sterile conditions, was followed for a period of 20 weeks.
(10) Environment groups Environment groups that have strongly backed low-carbon power have barely wavered in their opposition to nuclear in the last decade, although their arguments now are now much about the cost than the danger it might pose.
(11) Cultured cells from fourth to ninth passage showed positive labelling for S 100 protein, carbonic anydrase (CAA), glutamine synthetase (GS), alpha cristallin (alpha C) and polyclonal glial fibrillary acidic protein (GFAP) antibody, but were negative for both monoclonal GFAP antibody and also for Muller cells in the retina.
(12) They argue that the US, the world's largest producer of greenhouse gases per capita (China recently surpassed us in sheer volume), needs to lead the fight to limit carbon emissions, rather continuing to block global treaties as it has done in the past.
(13) Thin layers of carbon (20 microns) and vacuoles (30 microns) suggested a large temperature gradient along the tissue ablation front.
(14) Aryl hydrocarbon hydroxylase (AHH) inducibility, carbon monoxide in expired air (CO), serum gammaglutamyl-transferase (GGT), and total cholesterol were compared in equal-sized, age-matched samples of healthy middle-aged males born in 1921, 1934-1936, and 1946 attending the ongoing preventive medical population program in Malmö.
(15) The disappearance of ribosomes in Escherichia coli cells starved for a carbon source was studied.
(16) It was shown that the levels of ATP and ADP in the mycelium depended on the carbon source: the maximum and minimum ATP concentrations were found on the glucose and acetate media respectively, the maximum and minimum ADP concentrations showed inverse dependence.
(17) The mechanism by which such high levels were attained was primrily a combination of arterial hypoxia and a high carbon monoxide yield from tobacco.
(18) Nick Robins, head of the Climate Change Centre at HSBC, said: "If you think about low-carbon energy only in terms of carbon, then things look tough [in terms of not using coal].
(19) Immediately prior to and at maximal workloads, carbon monoxide shifted into extravascular spaces and returned to the vascular space within five minutes after exercise stopped.
(20) 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.
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.