X-Message-Number: 32931 Date: Wed, 13 Oct 2010 20:08:18 +0200 Subject: New paper from Alcor: Cryopreservation and Fracturing From: Jonano <> I'm happy to be an Alcor member. I just hope in the next 40 years, the technology and this science will improve so that I can benefit a good preservation. http://www.alcor.org/Library/html/CryopreservationAndFracturing.html Cryopatients are currently stored under liquid nitrogen at a temperature of -196A C. The first question that might come to mind is why so cold in the first place? The answer is provided in detail in the Alcor publication How Cold is Cold Enough? by Hugh Hixon [1]. In summary, when tissue is frozen, the freezing point of water is depressed by solutes concentrated between growing ice crystals. Water therefore remains a liquid (albeit a very viscous liquid) even at dry ice temperature (-79A C). Finally, usually at temperatures between -90A C and -130A C, a "glass transition" occurs and any remaining unfrozen water turns into a solid glass. Below this temperature, translational molecular motion is very slow to non-existent. With molecules able to do little more than vibrate in place, chemistry is effectively stopped, and extremely long storage times are possible. What do you think about this paper ? Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=32931