Vitrification


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vitrification

[‚vi·trə·fə′kā·shən]
(engineering)
Heat treatment of a material such as a ceramic to produce a glazed surface.
(geology)
Formation of a glassy or noncrystalline material.
(medicine)
An experimental procedure for preserving human organs in which chemicals are added prior to cooling to prevent crystallization of water within and outside the cells, so that with coolings the molecules essentially become fixed in place.

Vitrification

 

change of a liquid into a glasslike state when the temperature is lowered. Vitrification occurs in plants and animals as well as in their isolated organs and tissues when they are abruptly chilled (below -20° C). Tissue thus frozen in an amorphous glasslike mass remains viable a long time; if carefully thawed, the vital activity of tis-sues and whole organisms can be restored.


Vitrification

 

the transition of a liquid to a solid glassy state as it is supercooled. In contrast to crystallization, where the liquid-crystal transition occurs in jumps at the melting point (Tmp) vitrification involves the conversion of melts of certain inorganic and organic substances (quartz, silicates, phosphates, borates, sulfur), which are undergoing cooling and a gradual increase in viscosity, to a solid state at the vitrification temperature (Tv). Upon vitrification, a liquid retains (inherits) the structural elements that characterized the liquid at temperatures above Tv.

With an increase in viscosity from 108to 1012newtons·sec/m2(l newton·sec/m2 = 10 poises) in the Tmp – Tv range, there is a continuous change in other physicochemical properties of the liquid being cooled. For example, the specific volume and conductivity in this range have smooth curves when plotted against temperature; the coefficient of thermal expansion and the index of refraction undergo changes in jumps.

Table 1. Anomalous ranges of certain types of glass
GlassTVTmp
Window ...............550700
Household glassware ...............530630
Optical F2 ...............430570
Vitreous silica ...............12501250

Because of the peculiarities of the changes in properties in the interval between Tmp and Tv, this range is described as anomalous. The plastic state is characteristic of various types of glass within this range (see Table 1), while the brittle state characterizes glass at temperatures below Tv.

N. M. PAVLUSHKIN

vitrification

Of a clay product, the condition resulting when kiln temperatures are sufficient to fuse grains and close the surface pores, making the mass impervious.
References in periodicals archive ?
Vitrification protocols depended on several factors such as appropriate cryopreservation techniques, type and concentration of cryoprotectant, number of equilibration, warming steps and cryopreservation devices (12-14).
As a result Genea Biomedx has developed the world's first automated vitrification instrument, and has other projects well advanced in the product pipeline.
Most clinicians still use the approach of placing an embryo during the same cycle when the oocyte was harvested, "the way it's always been done, but at many clinics now they see that with vitrification they can get pregnancy rates that are similar to or even better than fresh embryo transfer.
Vitrification is considered the "gold standard" in terms of immobilizing wastes and protecting the environment.
Vitrification: Embryo vitrification at different cell stages, selection of vitrification carrier, practical aspects of setting up a clinical vitrification program, frozen embryo replacement protocols.
Vitrification involves the rapid freezing of embryos and eggs and improves survival rates by up to 20%.
Dr Sharif said vitrification uses high concentrations of cryoprotectants (the substance used to protect tissue from freezing damage) and an extremely high cooling rate of -20,000 to -25,000 degrees Celsius per minute.
Vitrification uses high concentrations of cryoprotectants and an extremely high cooling rate (-20,000- 25,000 [euro]centsC per minute) that solidify without the formation of ice crystal by direct immersion into liquid nitrogen in order for the oocytes to be transitioned from 37[euro]centsC to -196[euro]centsC in less than one second and can be stored for future use.
The results of this review compared the outcomes of slow freezing and vitrification methods with those achieved in fresh cycles in ART.
Mr Reeves said the vitrification is a tough radioactive working environment and the presence of heat and chemicals makes it even more hostile.
In the case of undertaking vitrification, DMEM supplemented with 2 M DMSO (Edwards Lifesciences, Irvine, CA), 1 M acetamide, 3 M propylene glycol (Reubinoff et al.
Midland Fertility Services, based in Aldridge, will be the first in the West Midlands to offer egg vitrification, which uses the latest 'flash-freezing' method.