(n.) A mineral having a glassy fracture, occurring in translucent trapezohedral crystals. It is a silicate of alumina and potash. It is found in the volcanic rocks of Italy, especially at Vesuvius.
(n.) A leucoplast.
Example Sentences:
(1) Quantitative x-ray diffraction was performed on the fast- and slow-cooled porcelain specimens with standards containing leucite volume fractions of 0.111, 0.223, 0.334, and 0.445.
(2) Recently introduced with pleasing aesthetic qualities, IPS-Empress (Ivoclar, Schaan, Liechtenstein), a new European leucite-reinforced glass-ceramic, has finally drawn attention in some journals and has been reviewed with promising in vitro test results.
(3) Unpaired, one-tailed t tests were performed on the fast- and slow-cool data, and a significant increase (p less than 0.05) in the amount of leucite (as a function of the slow cooling) was found for each of the porcelains.
(4) A better understanding of compatibility of alloy and ceramic during refiring schedules based upon leucite phase transformations and the ramifications for porcelain failure is emerging.
(5) Besides low leucite and glass, we have found a second crystalline phase in the sintered and slow-cooled porcelains that we propose to be potash feldspar (K2O.Al2O3.6SiO2).
(6) The present study was undertaken to determine whether the increase in porcelain thermal expansion might be attributable to crystallization of additional leucite during slow cooling of the porcelain.
(7) Ceramography confirms the martensitic (displacive) nature of the transformation from high (cubic) to low (tetragonal) leucite upon cooling.
(8) X-ray diffraction analyses verified the leucite content in metal ceramic systems and ceramics of the nonbonded systems.
(9) The chief ingredient of each porcelain was leucite (K2O .
(10) Comparing the metal ceramic systems with the nonbonded systems, an increase in leucite content was observed in the nonbonded systems.
(11) Most commercial dental porcelains designed for ceramo-metallic restorations are partially crystallized feldspathic glasses (glass-ceramics) that consist of low (tetragonal) leucite (K2O.Al2O3.4SiO2) crystals embedded in a glassy matrix.
(12) The purpose of this study was to test the hypothesis that high-leucite content feldspathic porcelain can be strengthened best by thermal tempering followed by ion exchange, compared with either thermal tempering or ion exchange alone.
(13) The increases in the leucite volume fractions resulting from the slow cooling ranged from a low of 8.5% to a high of 55.8%, with an average increase of 26.9%.
(14) The structure analysed in the scanning electron microscope showed leucite in the dendritic and idiomorphic form.
(15) Some other components were metal oxides used as pigment and opaque, for regulating the recrystallization of leucite in the fused porcelain, for controlling the thermal expansion, and for diffusing in the both sides of alloy and porcelain.
(16) The dentine materials of the metal ceramic systems VMK 68 and Biodent as well as the ceramics of all ceramic systems Duceram, Cosmotech, Optec, IPS-Empress and Corum were tested for their leucite content.
White
Definition:
(superl.) Reflecting to the eye all the rays of the spectrum combined; not tinted with any of the proper colors or their mixtures; having the color of pure snow; snowy; -- the opposite of black or dark; as, white paper; a white skin.
(superl.) Destitute of color, as in the cheeks, or of the tinge of blood color; pale; pallid; as, white with fear.
(superl.) Having the color of purity; free from spot or blemish, or from guilt or pollution; innocent; pure.
(superl.) Gray, as from age; having silvery hair; hoary.
(superl.) Characterized by freedom from that which disturbs, and the like; fortunate; happy; favorable.
(superl.) Regarded with especial favor; favorite; darling.
(n.) The color of pure snow; one of the natural colors of bodies, yet not strictly a color, but a composition of all colors; the opposite of black; whiteness. See the Note under Color, n., 1.
(n.) Something having the color of snow; something white, or nearly so; as, the white of the eye.
(n.) Specifically, the central part of the butt in archery, which was formerly painted white; the center of a mark at which a missile is shot.
(n.) A person with a white skin; a member of the white, or Caucasian, races of men.
(n.) A white pigment; as, Venice white.
(n.) Any one of numerous species of butterflies belonging to Pieris, and allied genera in which the color is usually white. See Cabbage butterfly, under Cabbage.
(v. t.) To make white; to whiten; to whitewash; to bleach.
Example Sentences:
(1) This study compares the mortality of U.S. white males with that of Swedish males who have had the highest reported male life expectancies in the world since the early 1960s.
(2) Cranial MRI revealed delayed myelination in the white matter but no brain malformation.
(3) Positivity was not correlated with current residence census tract socioeconomic indicators in black or white females.
(4) The urine compositions of the European mole Talpa europaea and of the white rat Rattus norvegicus (albino) kept on a carnivore's diet were compared.
(5) Fluttering in the background was a black flag adorned with white script, the “black flag of jihad”.
(6) The vulvar white keratotic lesions which have been subjected to histological examination in Himeji National Hospital (1973-1987) included 13 cases in benign dermatoses, 4 cases in vulvar epithelial hyperplasia, 3 cases in lichen sclerosus, and 3 cases in lichen sclerosus with foci of epithelial hyperplasia.
(7) Instead, the White House opted for a low-key approach, publishing a blogpost profiling Trinace Edwards, a brain-tumour victim who recently discovered she was eligible for Medicaid coverage.
(8) The flow properties of white cells were tested after myocardial infarction, by measuring the filtration rates of cell suspensions through 8 microns pore filters.
(9) The findings confirm and quantitate the severe atrophy of the neostriatum, in addition to demonstrating a severe loss of cerebral cortex and subcortical white matter in HD.
(10) Tottenham Hotspur’s £400m redevelopment of White Hart Lane could include a retractable grass pitch as the club explores the possibility of hosting a new NFL franchise.
(11) We identified four distinct clinical patterns in the 244 patients with true positive MAI infections: (a) pulmonary nodules ("tuberculomas") indistinguishable from pulmonary neoplasms (78 patients); (b) chronic bronchitis or bronchiectasis with sputum repeatedly positive for MAI or granulomas on biopsy (58 patients, virtually all older white women); (c) cavitary lung disease and scattered pulmonary nodules mimicking M. tuberculosis infection (12 patients); (d) diffuse pulmonary infiltrations in immunocompromised hosts, primarily patients with AIDS (96 patients).
(12) In 60 rhesus monkeys with experimental renovascular malignant arterial hypertension (25 one-kidney and 35 two-kidney model animals), we studied the so-called 'hard exudates' or white retinal deposits in detail (by ophthalmoscopy, and stereoscopic color fundus photography and fluorescein fundus angiography, on long-term follow-up).
(13) African Americans also have more outpatient episodes than whites.
(14) As a Native American I am pretty sensitive to charges of racism and white supremacy,” the Oklahoma congressman added.
(15) The White House denied there had been an agreement, but said it was open in principle to such negotations.
(16) The charges against Harrison were filed just after two white men were accused of fatally shooting three black people in Tulsa in what prosecutors said were racially motivated attacks.
(17) Today, she wears an elegant salmon-pink blouse with white trousers and a long, pale pink coat.
(18) The relative effect of the intramammary infections and of different factors related to the cow (parity, stage of lactation, milk yield) on the individual cell counts, were studied for 30 months on the 62 black-and-white Holstein cows of an experimental herd.
(19) The administration of stable analogue of the leu-enkephalin did not alter the concentration of cortisole and aldosterone in the blood of white male rats whereas this concentration increased after administration of the parathormone.
(20) The patient, a 12 year-old boy, showed a soft white yellowish mycotic excrescence with clear borders which had followed the introduction of a small piece of straw into the cornea.