X-Message-Number: 3190 Subject: CRYONICS: High Pressure CRYONICS From: (Ben Best) Date: Thu, 29 Sep 1994 01:49:00 -0400 (This is a modified reposting of a message evidently lost.) I have recently returned from Europe, where I spent some time with Klaus Reinhard, who is Germany's only signed-up cryonicist (he is an Alcor member). (There was another German Alcor member, but he terminated membership when he learned of the Alcor/CryoCare split.) Klaus has a friend, Nikolaus George Hergenhahn, who has training in physical chemistry. With Klaus Reinhard as translator, N-G Hergenhahn suggested to me that high pressure may be the best means of eliminating freezing damage. The following table for water inspired his thinking: Freezing Point Pressure Temperature (H20) (atmospheres) (degrees Celcius) 1 0 1,000 -10 2,045 -22 3,420 -17 6,160 0 7,390 10 9,800 25 13,970 50 36,500 175 The relevance of this table is that as pressure is increased, the freezing point of water falls to a low of -22 Celcius at 2,045 atmospheres, and then increases to a +175 degrees Celcius at 36,500 atmospheres. This table is inaccurate in the sense that I have taken values from different water-phase tables, but that should not matter, since the relevant figures are those at -22 Celcius and the freezing point temperatures at very high pressures. Hergenhahn suggests application of about 2,000 atmospheres to a brain at a temperature of about -20 Celcius (above freezing point) and then sudden increase in pressure to about 20,000 atmospheres in less than one second. Since the heat of fusion for water is 79 cal/gm, a temperature rise to +60 Celcius would not alter the rapid conversion of the brain to a solid state -- WITHOUT ice crystal formation. (The heat of fusion might actually be lower for a brain than for pure water.) (I was told that pressures of 100,000 atmospheres are used in the synthesis of artificial diamonds.) Pressure could then be maintained as the brain is cooled to some suitable temperature (perhaps room temperature) for long-term, high-pressure storate. Or perhaps the brain could remain vitrified and pressure could be removed after cooling to cryogenic temperatures. A crucial factor in the removal (and application) of high pressure would be the stress factors (possible cracking or other mechanical damage) and volume changes. Remarkably, the figures Hergenhahn showed me suggest that for +60 Celcius at 20,000 atmospheres there would be very little volume change for water. Greg Fahy froze kidneys at 1,000 atmospheres and found that this reduced viability -- a problem that was not encountered at 500 atmospheres. Nonetheless, Greg did not instantaneously apply pressure and he eventually released pressure -- with both operations being potentially damaging. In any case, Greg was concerned with viability, whereas high pressure cryonics is only concerned with eliminating structural damage. The problem of removing a human brain from the skull while keeping it viable could be difficult, but doing-so quickly at low temperature might eliminate the need for constant perfusion. As Klaus Reinhard pointed-out, Suda must have had a similar procedure for his cat brains. I would like to hear comments on the feasability of this proposal. Better yet, I would like to see people with money and technical capability get together and try some experiments on the brains of small mammals. -- Ben Best (ben.best%) Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3190