(n.) A common mineral embracing many varieties varying in color and in composition. It occurs in monoclinic crystals; also massive, generally with fibrous or columnar structure. The color varies from white to gray, green, brown, and black. It is a silicate of magnesium and calcium, with usually aluminium and iron. Some common varieties are tremolite, actinolite, asbestus, edenite, hornblende (the last name being also used as a general term for the whole species). Amphibole is a constituent of many crystalline rocks, as syenite, diorite, most varieties of trachyte, etc. See Hornblende.
Example Sentences:
(1) Three subcohorts were defined: 3212 men whose only exposure to asbestos was to amosite; 3430 exposed to crocidolite; and 675 to both amphiboles.
(2) Amphibole fibre counts were raised when compared with a non-occupationally exposed group and matched those seen in cases of pleural plaques, mild asbestosis, and mesothelioma.
(3) The second, with amphibole or glassy fibres, is mediated by fibronectin which first binds to the fibre.
(4) Six measures of asbestos-in-air concentration were considered: (1) total asbestos structures per cubic centimeter: (2) chrysotile structures per cubic centimeter; (3) amphibole structures per cubic centimeter; (4) structures per cubic centimeter at least 0.5 micron long and at least five times wide; (5) structures per cubic centimeter at least 5 microns long; and (6) structures per cubic centimeter at least 5 microns long and at least 0.2 micron wide.
(5) The ingestion of filtered water results in the eventual disappearance of amphibole fibers from urine.
(6) When fibre-length distributions were calculated using a scanning electron microscope, however, it was found that the chrysotile clouds used in this study contained many more fibres over 20 microgram long than either of the amphibole clouds.
(7) A suitable quarry was found about 11 km from the port but unfortunately the rock was found to be contaminated to a small extent with a fibrous mineral identified with the analytical transmission electron microscope as a non-commercial type of fine amphibole with many long fibres.
(8) The most positive lavages, probably reflecting exposure to industrial amphiboles, were found in patients presenting with radiological evidence of asbestosis.
(9) The amphibolic asbestos types lie in the upper half and the rock wool sample in the lower half of the range.
(10) Based on the results obtained, the following metabolic pathway is proposed: isopropylbenzene----2,3-dihydro -2,3-dihydroxyisopropylbenzene----3-isopropylcatechol----2 -hydroxy-6-oxo-7-methylocta-2,4-dienoate----isobutyrate + 2-oxopent-4-enoate----amphibolic intermediates.
(11) While amphibole cleavage fragments are usually visible by PCM, asbestos fibers (such as amosite and chrysotile) have finer widths that may render them invisible by PCM.
(12) In general, chrysotile had a toxic effect on the macrophages, whereas amphibole varieties did not.
(13) Of particular importance is an apparent increase in the proportion of mesothelioma risk attributable to tremolite, since the fibers heretofore most responsible for that disease--commercial amphiboles--have been or are being severely regulated or completely eliminated in production and use.
(14) The first reported case was a village woman whose lung tissue contained amphibole asbestos fibres, which were later identified as tremolite.
(15) Crocidolite fiber, a commercial amphibole not native to the region, was nonetheless identified in lung tissue from 15 of 23 chrysotile miners and millers.
(16) There was a rather good correlation between numbers of amphibole fibers and asbestos bodies, with an average ratio of 10:1.
(17) Chrysotile asbestos was much more active in binding IgG than was amphibole asbestos.
(18) Analytical electron microscopy of asbestos body cores showed that in the BL group 95.6% were chrysotile fibres whereas in the AC group amphiboles accounted for 93.1%.
(19) The magnesium amphibole contained the longest (6.03 microns) fibres, and the nickel amphibole contained the shortest (2.7 microns) fibres, resembling those of crocidolite.
(20) Electron microscopic examination of these water samples confirms the presence of asbestiform amphibole fibers.
Magnesium
Definition:
(n.) A light silver-white metallic element, malleable and ductile, quite permanent in dry air but tarnishing in moist air. It burns, forming (the oxide) magnesia, with the production of a blinding light (the so-called magnesium light) which is used in signaling, in pyrotechny, or in photography where a strong actinic illuminant is required. Its compounds occur abundantly, as in dolomite, talc, meerschaum, etc. Symbol Mg. Atomic weight, 24.4. Specific gravity, 1.75.
Example Sentences:
(1) The following conclusions emerge: (i) when the 3' or the 3' penultimate base of the oligonucleotide mismatched an allele, no amplification product could be detected; (ii) when the mismatches were 3 and 4 bases from the 3' end of the primer, differential amplification was still observed, but only at certain concentrations of magnesium chloride; (iii) the mismatched allele can be detected in the presence of a 40-fold excess of the matched allele; (iv) primers as short as 13 nucleotides were effective; and (v) the specificity of the amplification could be overwhelmed by greatly increasing the concentration of target DNA.
(2) Subunits maintained under the above ionic conditions were compared with 30S and 50S particles at low (6 mM) magnesium concentration with respect to the reactivity of individual ribosomal proteins to lactoperoxidase-catalyzed iodination.
(3) The association constants K'A, KN, and K'N in the scheme (see article), were determined for the magnesium salts of ADP, adenyl-5'-yl imidodiphosphate AMP-P(NH)P, and PPi.
(4) Simple interconversion cannot account for the changes in binding that occur upon adding GMP-PNP or removing magnesium, since the increase in [R2]t exceeds the decrease in [R1]t. Moreover, the apparent amount of high-affinity complex exhibits a biphasic dependence on the concentration of [3H]histamine; an increase at low concentrations is offset by a decrease that occurs at higher concentrations.
(5) There were no relationships between blood pressure and calorie-adjusted intakes of fats, carbohydrates, sodium, potassium, calcium or magnesium.
(6) Renal excretion of calcium and magnesium postflight was higher than preflight.
(7) Although GTP most potently inhibited [125I]beta h-endorphin binding in the presence of sodium, inhibition of [125I]beta h-endorphin binding by GTP was also observed in the presence of the monovalent cations lithium and potassium, but not the divalent cations magnesium, calcium, or manganese.
(8) The contents of magnesium, potassium and zinc plasma did not correlate with the corresponding concentrations in skeletal muscle or circulating blood cells, as investigated in healthy controls, diabetics and in all subjects together, implying that the plasma concentrations are not useful in the assessment of electrolyte status.
(9) The decomposition of nafcillin and penicillin G solutions was hastened significantly by magnesium sulphate due to effect on the pH values of the solutions.
(10) In the present study, maternal and fetal zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), magnesium (Mg), and calcium (Ca) status has been studied in Sprague-Dawley (SD) and Wistar rats.
(11) The effect of age of the ewe and pregnancy on concentrations of plasma calcium, phosphorus and magnesium and its relationship to the bent-leg syndrome in lambs, were investigated.
(12) The slight radioprotective action of inosine, when injected intraperitoneally to mice shortly before gamma-irradiation, can be enhanced by the administration of magnesium aspartate.
(13) Thus, magnesium may be useful in the management of ventricular fibrillation during ischemia.
(14) It depended on the quantal content and 3-exponential EPC could be transformed in 2-exponential and later to monoexponential ones if increasing concentration of magnesium ions.
(15) The effect of volume expansion on sodium, calcium and magnesium remaining in the proximal tubule was relatively modest and not affected by furosemide.
(16) The dietary intake of magnesium is borderline compared with the recommended dietary allowances.
(17) Metabolism of carbaryl by the fat body is affected by the age of the larva, the pH of the incubation medium, and the concentration of magnesium chloride in the incubation medium.
(18) All calcium, magnesium, and zinc contents per bone decreased in the 1- and 2-mg caffeine groups as compared to either controls or 0.5-mg caffeine group, whereas phosphorus stayed relatively constant regardless of the different levels of caffeine intake.
(19) Magnesium (Mg) deficiency, nicotine, and high dietary cholesterol are contributing factors that accentuate adverse effects of vitamin D.
(20) With magnesium-Ringer as external bathing solutions, amiloride and ouabain failed to stimulate oxygen consumption.