X-Message-Number: 3424 Date: 21 Nov 94 14:17:08 EST From: yvan Bozzonetti <> Subject: CRYONICS: CO2 drying Emma Young reports in the November 19 issue of New Scientist about supercritical CO2 drying. At 40 degree C and 90 bar, carbon gas becomes supercritical, it is at the same time a gas, a liquid and a solid. Its ability as solvent is used to extract cafeine from whole coffee grains. With 2,2 dimethoxypropane, water is turned into methanol and acetone, both are then removed with supercritical CO2 ( water is not directly soluble into CO2). For objects such wood there is less cell damage than with freeze drying. It remain to be seen if the CO2 bath doesn't remove usefull molecular compounds. If there is no such problems, CO2 could look as a promising way: a full processing takes four days against months for a good freeze drying. Without liquid water, protein are denatured and there is no proof the effect would be reversible. Such conservation must be seen as an information preservation for copying on a material or virtual medium. It would for example be legal in British Columbia, because there is no possibility to live again for the storred corpse. On the technical ground, the 90 bar presure is less than what is found in air bottles used for diving. The temperature is not very high and some antioxydants could limit any chemical destruction. Yvan Bozzonetti. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3424