From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Thu Jul 11 2002 - 13:56:51 MDT
Michael Dickey wrote:
> The reason I am asking is because I have read of 'bulk metallic glass',
> that is, the vitrification of large chunks of molten steel solidifies the
> metal without crystallization. As far as I know the process requires a very
> rapid cool down, going from molten metal to solid temperatures in seconds.
Precisely and the heat transfer characteristics of a human body
(essentially salt water) don't allow that. Cells may be ~3 cell
widths away from the nearest capillary and the entire capillary
system is pressure (and therefore heat transport) limited.
I believe the vitrification process Greg is working on is an attempt
to perfuse the capillaries and cells with liquids that are highly
resistant to forming crystal nuclei and combine that with
appropriate pressures to limit crystal formation.
But here is the way I think about it.
a) Are you going to know the complete genetic sequence of the
individual?
Yes. Even if you get ice crystals slicing and dicing the DNA
during the freezing process, you have so many copies of your
genomic sequence that you will be able to recover it. (It
is worth noting that the shotgun sequencing methods used
to sequence genomes today start by segmenting the genomes
into small fragments first, then reassembling them on the
computer after many fragments are sequenced.)
b) Are you going to know the complete 3D structure of all of
the proteins in your body?
Yes. Either through X-ray crystallography, NMR or computer
simulations (e.g. Blue Gene) we will likely have all this
information within this decade.
These two facts suggest to me that any damage that is done
to the actual molecules during freezing should easily be
repairable.
c) Is your neural network a unique 3D map?
Presumably yes. Even if a crystal or complete fracture
slices through an synapse or axon and repositions it
10, 100, 1000 nm away it should still form a unique 3D
jigsaw puzzle that can only go back together correctly
just one way.
So, IMO, there is too much emphasis placed on the damage
caused during freezing. That we will be able to deal
with.
More emphasis needs to be placed on (a) Making sure the
bodies/heads are safely preserved; (b) whether there
might be any showstoppers during a recovery process,
e.g. nanorobots cannot grasp axons sufficiently
well or operate within synaptic clefts (too small
a volume) to be able to put everything back in its
proper place. Though in theory, one ought to be able
to direct the assembly of a copy of the neural net that
is a functional equivalent of the original. Of course
this raises the ugly issue of it not being "oneself".
For people who haven't read it, the current best effort
discussing reanimation is Ralph Merkle's paper:
The Molecularr Repair of the Brain, parts I and II,
Cryonics, January & April 1994, Vol. 15 No's 1 & 2.
http://www.merkle.com/cryo/techFeas.html
Robert
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