Re: CRYONICS: feasibility [was Re: Fox cryonics show]

From: hal@finney.org
Date: Sun Feb 06 2000 - 20:04:49 MST


Robert J. Bradbury, <bradbury@aeiveos.wa.com>, writes:
> This is pretty much the question I'm trying to get at. Hal responded
> to some degree expressing his doubts. From my perspective, the
> questions are:
> (a) Does the process of ice crystal formation develop enough force
> to break interatomic bonds or will the crystals almost universally
> disrupt H-bonds and Van der Waals interactions?

I am concerned about synaptic structure. I don't know how rigidly the
synapse is held together, but I suspect that a growing ice crystal could
separate, perforate and even shred the membranes. I would suspect that
cell membranes are not strong enough to withstand ice crystal penetration.
I have the impression that synapses are relatively gently bound together.

> (b) What is the probability that within a some fixed (sub-cellular) volume
> that I will have identical surfaces that preclude putting things back
> together exactly the way they were originally?

The problem is that the shapes may not match very well once the ice
is removed. As the ice is forming, the material around it is at least
a semi liquid. Water flows out of the cells and they would partially
collapse due to dehydration. The cells themselves would be shoved
around by the ice, tugged and torn, and their shapes will change.

Hal



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