X-Message-Number: 1940 From: Ralph Merkle <> Subject: Glass Transition Temperature Storage Date: Wed, 10 Mar 1993 18:09:33 PST Storage at or near the glass transition temperature should indeed be able to reduce or eliminate the kinds of fracture damage that occurs today with storage at the temperature of liquid nitrogen. However, the kind of fractures that occur in a glassy substance should result in little or no loss of structural or ultrastructural information. As a consequence, if the objective is to provide the highest possible probability of information theoretic survival, then storage at or near the glass transition temperature offers little if any benefit over storage at the temperature of liquid nitrogen. Given the damage done by current suspension methods (and the likely requirement for a mature nanotechnology to achieve a satisfactory cure), the benefits of storage at the glass transition temperature are marginal. If and when "fully reversible" (e.g., reversible using today's technology) brain cryopreservation is achieved, storage near the glass transition temperature might offer the potential benefit of a cure without the need for a mature nanotechnology. In the meantime, storage in liquid nitrogen is safe, simple, reliable, and cheap. Any competing proposal for storage near the glass transition temperature must have these desirable properties for serious consideration, and a relatively conservative stance should be taken towards its adoption. Cheers! Ralph C. Merkle Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=1940