Re: CRYONICS: Limits to storage [was: Where to look for the answers...]

Date: Thu Apr 27 2000 - 17:35:28 MDT

Rober writes:
> As I've stated before, and I'll state again, the limits on
> cryonic reanimation would appear to be fundamentally based
> on the question of whether or not the freezing process causes
> loss of positional information that could prevent 3D-reassembly.
> Given the size of synaptic and cellular structures, I strongly
> doubt that to be the case. These are hundreds of thousands to
> tens-of-millions of atoms in size. They are only going to match
> up in unique places. Only if you unfreeze the brain and let it
> decay away into a molecular soup have you lost that information.

I don't want to fully reopen the debate we had a few weeks ago about
this, but I do want to point out that this model makes most sense if
you think of the tissue as being frozen and then cracked apart. In
that case the problem is putting the pieces back together, and as you
say they would probably match up in unique places.

However in fact freezing is a dynamic, possibly chaotic process.
Ice crystals grow and spread through the tissues like spears, providing
signifcant mechanical stresses to cells that are still in the unfrozen
state. The chemistry of the intercellular medium changes drastically, as
water freezes and the concentration of larger molecules rises. The cells
dehydrate as fluids flow through the channels or perhaps even through
tears in the membrane, putting things into a highly unnatural state.

This whole process occurs before the local tissue actually freezes.
Once everything gets vitrified and/or frozen, things will pretty much
stay where they are, although there may be cracking and shifting at
some scale. But even before things are frozen there will be damage.
All of that occurs in the fluid state, and putting things back won't be
as easy as assembling a jigsaw puzzle.


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