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The ultimate objective is to freeze the specimen so rapidly (at 10 4 to 10 6 K per second) that ice crystals are unable to form, or are prevented from growing big enough to cause damage to the specimen's ultrastructure. The formation of samples containing specimens in amorphous ice is the "holy grail" of biological cryomicroscopy. [citation needed]
Controlled-rate and slow freezing, also known as slow programmable freezing (SPF), [18] is a technique where cells are cooled to around -196 °C over the course of several hours. Slow programmable freezing was developed during the early 1970s, and eventually resulted in the first human frozen embryo birth in 1984. Since then, machines that ...
A cryoprotectant is a substance used to protect biological tissue from freezing damage (i.e. that due to ice formation). Arctic and Antarctic insects, fish and amphibians create cryoprotectants (antifreeze compounds and antifreeze proteins) in their bodies to minimize freezing damage during cold winter periods. Cryoprotectants are also used to ...
At least six major areas of cryobiology can be identified: 1) study of cold-adaptation of microorganisms, plants (cold hardiness), and animals, both invertebrates and vertebrates (including hibernation), 2) cryopreservation of cells, tissues, gametes, and embryos of animal and human origin for (medical) purposes of long-term storage by cooling to temperatures below the freezing point of water.
During the final stage of freezing, an ice drop develops a pointy tip, which is not observed for most other liquids, and arises because water expands as it freezes. [8] Once the liquid is completely frozen, the sharp tip of the drop attracts water vapor in the air, much like a sharp metal lightning rod attracts electrical charges. [8]
By freezing at an ultra-fast rate and using osmotic dehydration, the water that is still present in the cell is unable to form crystals and will be part of a glass-like or vitrified solution. [10] This method can be further split in different variants e.g. droplet vitrification, encapsulation dehydration and plate vitrification.
The frozen section procedure as practiced today in medical laboratories is based on the description by Dr Louis B. Wilson in 1905. Wilson developed the technique from earlier reports at the request of Dr William Mayo, surgeon and one of the founders of the Mayo Clinic [3] Earlier reports by Dr Thomas S. Cullen at Johns Hopkins Hospital in Baltimore also involved frozen section, but only after ...
Real-time Java is a catch-all term for a combination of technologies that enables programmers to write programs that meet the demands of real-time systems in the Java programming language. Java's sophisticated memory management , native support for threading and concurrency, type safety , and relative simplicity have created a demand for its ...