(n.) The regular form which a substance tends to assume in solidifying, through the inherent power of cohesive attraction. It is bounded by plane surfaces, symmetrically arranged, and each species of crystal has fixed axial ratios. See Crystallization.
(n.) The material of quartz, in crystallization transparent or nearly so, and either colorless or slightly tinged with gray, or the like; -- called also rock crystal. Ornamental vessels are made of it. Cf. Smoky quartz, Pebble; also Brazilian pebble, under Brazilian.
(n.) A species of glass, more perfect in its composition and manufacture than common glass, and often cut into ornamental forms. See Flint glass.
(n.) The glass over the dial of a watch case.
(n.) Anything resembling crystal, as clear water, etc.
(1) Such a signal must be due to a small ferromagnetic crystal formed when the nerve is subjected to pressure, such as that due to mechanical injury.
(2) A comprehensive review of the roentgenographic features of calcium pyrophosphate crystal deposition disease (pseudogout) is presented.
(3) CW Nd:YAG light transmitted by fiber optic cable and sapphire crystal was applied transsclerally to the ciliary body of pigmented and albino rabbits.
(4) The crystal structure of the biological stain, "acridine orange," has been determined.
(5) Urinalysis revealed a low pH, increased ketones and bilirubin excretion, dark yellowish change in color, the appearance of "leaflet-shaped" crystals and increased red blood cells and epithelial cells in the urinary sediment, increased water intake, decreased specific gravity and decreased sodium, potassium and chloride in the urine.
(6) Early in the regression process, cholesterol esters are reduced at least partly by hydrolysis to yield cholesterol, some of which may crystallize and inhibit rapid regression.
(7) Here we determine the position of bound ADP diffused into the recA crystal.
(8) The virus material in these crystals had been subjected to treatment with EDTA at pH 8.0 before crystallization at pH 6.5.
(9) Results obtained show that chlorophyll is more active than other inhibitors studied and suggest a higher surface adsorption intensity on the primary sources of the crystal surface.
(10) The "Mg(2+)-Sarkosyl crystals" (M band) technique distinguishes between membrane-bound and free intracellular DNA.
(11) The molecular structure of the hexagonal crystal form of porcine pepsin (EC 3.4.23.1), an aspartic proteinase from the gastric mucosa, has been determined by molecular replacement using the fungal enzyme, penicillopepsin (EC 3.4.23.6), as the search model.
(12) In vitro experiments show that these macromolecules are able to interact with specific faces of different crystals, influencing both nucleation and crystal growth.
(13) 2 Each of the drugs significantly increased leucocyte cyclic AMP content within 3 h of the injection of crystals.
(14) For Kevin Phillips, just like Wilfried Zaha, this might have been his final act as a Crystal Palace player.
(15) In ancillary studies, multiple cycles of direct dissolution of UCB crystals revealed a progressive decrease in aqueous solubility of UCB as fine crystals were removed; this effect was minimal in CHCl3.
(16) Six dogs were instrumented with electromagnetic flow probes and subendocardial ultrasonic crystals.
(17) The crystallization of the lipase was successfully carried out.
(18) The values of the energy level distributions in crystals obtained from the measurements and analysis reported here are compared with those obtained by a different method for the same protein complex in frozen solution.
(19) The crystal structure of proteolytically modified human ACT has been solved at 2.7-A resolution (Baumann et al., 1991).
(20) These observations support our hypothesis that calcium pyrophosphate dihydrate crystal deposition in joints is regulated by the physical chemical gel state of the connective tissue matrix.
Devitrification
Definition:
(n.) The act or process of devitrifying, or the state of being devitrified. Specifically, the conversion of molten glassy matter into a stony mass by slow cooling, the result being the formation of crystallites, microbites, etc., in the glassy base, which are then called devitrification products.
Example Sentences:
(1) This suggests that the devitrification occurring during the use of these materials in high-temperature environments will not necessarily enhance their adverse biological activities despite the production of one phase of crystalline silica.
(2) Devitrification (ice formation during warming) is one of the primary obstacles to successful organ vitrification (solidification without ice formation).
(3) The fibres were examined in the 'as-manufactured' state and after heating at 1200 and 1400 degrees C. Devitrification of the fibres at 1200 degrees C probably gave mullite crystals on the surface and caused the formation of the high-temperature form of cristobalite and, in zirconia grade fibres, the high-temperature, tetragonal form of zirconia as well.
(4) The highest heating rates we observed using catheters occurred at temperatures ranging from about -70 to -40 degrees C, the temperature zone where devitrification usually appears in unstable solutions during slow warming.
(5) Biological data showed that this devitrification was associated with severe loss of cell function.
(6) This, together with the RGA results, suggests the absence of devitrification or ice crystal growth during the drying procedure.
(7) Of particular note is the anomalous shift in devitrification temperature (Td) to lower temperatures following increased time of annealing at sub-Tg temperatures.
(8) The purpose of the present studies was to define the devitrification process: to determine nucleation rates, ice-crystal growth rates, and the distribution of ice-crystal size and to evaluate the applicability of existing quantitative models of these processes which have successfully approximated the behavior of other aqueous systems.
(9) Very high rates of survival (77-89%) of oocytes exposed to the cryoprotectant media, but without the vitrification, together with extreme variability in results between straws in the vitrified groups, suggest that losses in viability during vitrification may result from ice damage during devitrification of the medium.
(10) Devitrification is a major problem which must be overcome for successful organ cryopreservation.
(11) However, if these cell suspensions were warmed rapidly to -70 degrees C and then held for 5 min, allowing devitrification to occur, the preparation contained significant amounts of both intra- and extracellular ice.
(12) Results obtained indicate that drying is complete below the devitrification temperature of amorphous phase tissue water.
(13) It appears that it should be possible to warm vitrified rabbit kidneys rapidly enough under high-pressure conditions to protect them from devitrification.
(14) As a result of these studies we concluded that: intracellular freezing is lethal, but avoidance of freezing during fast cooling is not sufficient to provide complete protection; a subtle freezing injury in the cryoprotected monocytes can be correlated with a measurable increase in devitrification on warming; and the cell contents form more stable glasses than the Hanks' balanced salt solution with fetal calf serum used as the extracellular medium.
(15) In both cases, high survival requires that subsequent warming be rapid, to prevent recrystallization or devitrification.
(16) A systematic study of the errors of low-temperature recording of kinetics of the cytochrome oxidase-CO reaction had identified the classic devitrification process of Keilin & Hartree [(1950) Nature (London)165, 504-505].
(17) Devitrification can be initiated on fracture planes and on bubbles, but the focus of attention here is on devitrification by ordinary heterogeneous and homogeneous mechanisms, which are the most relevant for organ preservation by vitrification.
(18) An apparatus has been produced that can remove amorphous phase tissue water via molecular distillation without devitrification or rehydration.
(19) Whether corneas can be cooled fast enough in these solutions to achieve vitrification and warmed fast enough to avoid devitrification remains to be determined.
(20) Glass transitions, devitrification, recrystallization and melting behaviour of aqueous solutions of polyvinylpyrrolidone, hydroxyethyl starch and dextran have been established.