(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.
Tridymite
Definition:
(n.) Pure silica, like quartz, but crystallizing in hexagonal tables. It is found in trachyte and similar rocks.
Example Sentences:
(1) The crystals with more irregular surfaces and protruding oxygen atoms, which form surface pockets (quartz, tridymite, and cristobalite), showed a dramatic increase over saline controls for lung index (greater than 2 x), cell number and lavage protein concentration (greater than 4 x), and hydroxyproline level (greater than 2 x).
(2) Kieselguhr is a greyish-white powder which is made by heating lake ooze containing diatom skeletons to a temperature of about 1000 degrees C. It contains quartz, cristobalite and tridymite.
(3) Since crystalline silica is present in the occupational environment, the airborne dust content of various polymorphs of silica, especially quartz, cristobalite and tridymite, was determined by X-ray diffraction analysis.
(4) Complementary experiments with tridymite filtrates suggested that phagocytosis of tridymite particles by monocytes was a necessary step for the induction of SCEs in human lymphocytes.
(5) The crystals studied were quartz, tridymite, cristobalite, coesite, anatase, and rutile.
(6) As evidenced by IR spectroscopy, super microhardness of CGC, observed in practice, appears to be related to their higher solidity in contrast to that of Gamma porcelain, structurally similar to amorphous silica, and that of Sikor characterized by a poorly crystallized tridymite structure.
(7) The abilities of Min U Sil quartz or tridymite particles to induce sister chromatid exchanges (SCEs) in cultures of human lymphocytes plus monocytes or of human purified lymphocytes were investigated.