(n.) Calcium carbonate, or carbonate of lime. It is rhombohedral in its crystallization, and thus distinguished from aragonite. It includes common limestone, chalk, and marble. Called also calc-spar and calcareous spar.
Example Sentences:
(1) The crystallographic orientation of the calcite also appears to be independent of these fibrils.
(2) The calcium carbonates-calcite, aragonite, and vaterite-constitute most of the remainder of the calculi.
(3) Crystallographic analysis of stones from patients with nutritional pancreatitis (NP), as well as alcoholic pancreatitis (AP), revealed that the main constituent was calcite (CaCO3).
(4) Calcite was present in all stones, vaterite in 12%, and a central amorphous material in 30%.
(5) X-ray diffraction showed that calcite (CaCO3) was the major crystalline constituent of the calcareous deposits.
(6) When the doped glasses have been immersed in a physiological solution (199 medium), a film of calcite forms on the glass surface and this modification is related to the type of doping agent used, decisive for close linking between metal supports and the glass.
(7) We suggest that precipitation of calcite in the pancreatic duct occurs as the primary event in the formation of pancreatic calculi and that it may continue until the duct is completely occluded.
(8) 5-7): calcite and quartz are the principal components of the sinters, additional diffuse apatite lines appear in bone samples.
(9) These features are characteristic of sea urchin (Echinoderm) spines which are composed of ornately formed calcite crystals covered by an epithelium.
(10) Its absence in all analyzed invertebrate tissues (including calcitic, aragonitic, and apatitic mineral phases) indicates that matrix protein-bound gamma-carboxyglutamic acid is not obligatory for the calcification process in the invertebrates.
(11) Quantitatively, phosphate is by far the most important inhibitor of calcite precipitation present in saliva, suggesting that inhibition of calcite precipitation by the macromolecules may be of secondary significance.
(12) Plates of calcite (CaCO3) were implanted in rabbit tibiae, and their biocompatibility and bonding ability to bone were studied.
(13) Subsequent increase in diameter of the rod involves the radial development of irregular columns of calcite which arise from the peripheral nodules.
(14) The phenomenon of dissolution and recrystallisation in situ of the calcite can be a trap because it can be a reservoir for micro-organisms.
(15) Synechococcus strain GL24 was isolated from Fayetteville Green Lake, New York, where it has a demonstrated role in the formation of calcitic minerals.
(16) Pancreatic stones are observed in both humans and cattle, and are approximately 95% CaCO3 (calcite) in both species.
(17) Skeletal walls of more than one mineralogy have the magnesium-rich layer (calcite) surrounding the living chamber and the strontium-rich layer (aragonite) on the outside.
(18) Here we report on the ability of a soil bacterium to synthesize calcite in a calcium-stressed environment.
(19) Formation of inner protein nidus in the form of a cobweb is the first stage, then calcite is deposited on this fibrous network as tiny crystals.
(20) The biocompatibility of mammal bone with aragonite and calcite skeletons of aquatic invertebrates (Corals, Molluscs) led us, after animal experimentation, to implant in humans artificial dental roots derived from such invertebrates.
Quartz
Definition:
(n.) A form of silica, or silicon dioxide (SiO2), occurring in hexagonal crystals, which are commonly colorless and transparent, but sometimes also yellow, brown, purple, green, and of other colors; also in cryptocrystalline massive forms varying in color and degree of transparency, being sometimes opaque.
Example Sentences:
(1) There fore, the adverse effects may be induced by such quartz or silicon compounds.
(2) We have previously shown that intratracheally instilled silica (quartz) produces both morphologic evidence of emphysema and small-airway changes, and functional evidence of airflow obstruction.
(3) Lung sections of rats exposed to quartz particles were significantly different.
(4) Exposures to quartz amounting to less than about 10 per cent of mixed coal mine dust do not generally affect the probability of developing simple pneumoconiosis.
(5) The effect of quartz, bentonite and coal dusts as well as the effect of the artificial mixture of these dusts on TTC reduction and extra-and intra-cellular lactate dehydrogenase activity in peritoneal rat macrophages was determined in vitro.
(6) Silica quartz dust, a direct toxin of macrophages, suppressed demyelination and inflammation if begun at time of virus infection.
(7) As expected the proportion of quartz was greater in lymph nodes and lungs from men who had worked "low" rank (high ash) coal.
(8) Guinea pig splenic lymphocytes and peritoneal macrophage cultures were incubated with quartz (DQ12), Corundum and aspirin as prostaglandin inhibitor.
(9) A surgical system using 308 nm excimer laser radiation transmitted by quartz fibers is described.
(10) Cancer incidence and cause-specific mortality were studied in a male cohort of 94 talc miners and 295 talc millers, exposed to non-asbestiform talc with low quartz content.
(11) The pulsed dye laser can effectively fragment biliary calculi when transmitted through a small-diameter quartz fiber and may be useful as a tool for fragmenting retained common duct stones.
(12) In mice bearing the highly metastatic tumors B16 melanoma and Lewis lung carcinoma (LLC) treated with Hpd and laser light delivered through a quartz fiber optic significantly prolonged the median survival time.
(13) With a long-term (1 and 4 months) introduction of an additional amount of edible fats (beef, hog fats, butter, sunflower seed oil) to intact and intratracheally quartz-dust laden sexually mature male rats an organ-specific reaction to the supply of fat, and in intact rats, also some peculiarities of the reaction depending upon the kind of the introduced fats, were discovered.
(14) Using a fluorescence microscope with quartz optics and an image analyser, it was possible to measure the intracellular concentration of free calcium ions [Ca2+]i in single microvessels for the first time.
(15) The median amount of quartz for all cases, was 0.044 grams.
(16) The microscope is focused on an in-line quartz flow cell incorporated down stream of a microbore HPLC column or directly on an optically clear portion of fused-silica capillary columns for analyte detection.
(17) X-ray diffraction data from samples of 20, 60 and 100 mug quartz on poly-vinyl chloride membrane filters have been collected using a rotating anode x-ray source.
(18) Mentally,” an Uber driver who used to do contract limo work told a reporter from business magazine Quartz last week, “these rating systems affect us a lot… If I am driving somebody who doesn’t live in New York, and they complain that I took the wrong route, how would they know the route that I should have taken?” He went on to note that in 20 years of working with corporate employees, he hadn’t a single customer complaining.
(19) There are closed relations between progressive systemic sclerosis (PSS) and exposure to quartz dust in the GDR.
(20) A 630 nanometer wavelength of light was delivered through a quartz-optical fiber with either a regular flat end for focal illumination or a bulb-type end which produced an isotropic light pattern.