X-Message-Number: 4776
From: Garret Smyth <>
Newsgroups: sci.cryonics
Subject: Re: Blue Blood
Date: Sun, 13 Aug 95 14:27:07 GMT
Message-ID: <>
References: <40j3nk$>

> : > Ice expansion is a real problem for large object such a corpse.
 
> : I understand that this *isn't* a problem.

> Actually, there is a LOT of mechical damage at the macroscopic scale if a 
> whole body is placed in cryogenic suspension.  According to the FAQ, at 
> least one whole-body patient has been examined and found to have 
> extensive fracturing of internal organs, including the spinal cord 
> (remember, CNS tissues show great tolerance for freezing and thawing in 
> lab experiments).

Yes, there is cracking, but it is not thought to be because of the expansion

of water turning into ice. The peculiarity of water compared to other substances
is because of the molecular structure that occurs as it solidifies (actually,
although school is a long way off, I vaguely recall that expansion actually 
starts at around 4 degrees C). The bonds that form the molecules into the neat
lattice of a solid are long enough that the molecules in ice are further apart
that in water of the same temperature. However, as ice gets colder, it 
contracts.

The cracking in large tissue samples is usually attributed to mechanical strain
because of a temperature gradient. One part of the patient has contracted more
than the rest and stress is built up. Also, it is thought to occur only at
fairly low temperatures when expansion has finished. There has been a lot of
discussion of methods to overcome the problem - the main topics being rates of 
cooling and also a cheap and reliable method of storage at the relatively hot
temperature of -130(ish) degrees c.

Probably any solvent would have similar problems, (but this is a wild guess.)

One answer to the cracking problem is a bit of a "our friends in the future"
type (meaning we don't need to worry about it because those awfully nice people
in the future who will have nanotechnology, infinite wisdom, a cure for 

cellulite, and the ability to make every day the first day of spring, will sort
it out just and not charge us a penny). It isn't a bad one though, as that sort
of arguement goes: clean cracks that occur in solids should allow us (or our
friends in the future) to map both surfaces and work out where they fitted 
together, and then knit up the molecules. It may well be easier than repairing
very fine damage.

Research is going on into this I understand (but of course, too little) so try
to stay alive for the moment.

TTFN

Garret
-- 
Garret Smyth

Phone:  0181 789 1045 or +44 181 789 1045


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