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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 ...
The Downs cell uses a carbon anode and an iron cathode.The electrolyte is sodium chloride that has been heated to the liquid state. Although solid sodium chloride is a poor conductor of electricity, when molten the sodium and chloride ions are mobilized, which become charge carriers and allow conduction of electric current.
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]
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 ...
During slow freezing, cells are placed in a medium which is cooled below the freezing point using liquid nitrogen. This causes an ice mass to form in the medium. As the water in the medium freezes, the concentration of the sugars, salts, and cryoprotectant increase.
The solenoid moves the grinding media back and forth inside the vial, grinding the sample down to analytical fineness. This type of milling is especially useful in milling temperature sensitive samples, as samples are milled at liquid nitrogen temperatures. The idea behind using a solenoid is that the only "moving part" in the system is the ...
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Flash freezing being used for cryopreservation. Flash freezing is used in the food industry to quickly freeze perishable food items (see frozen food). In this case, food items are subjected to temperatures well below [clarification needed] the freezing point of water. Thus, smaller ice crystals are formed, causing less damage to cell membranes. [3]