[ExI] Help with freezing phenomenon

[Eugen Leitl]

On Sat, Jan 29, 2011 at 10:49:34AM -0700, Keith Henson wrote:
> On Sat, Jan 29, 2011 at 5:00 AM,  "spike" <spike66 at att.net> wrote:
> 
> > ... On Behalf Of Keith Henson
> 
> >>...Spike, the point of all current procedures is to vitrify without any
> > freezing at all, i.e., NO expansion...
> >
> > There is that, but I myself have not been convinced that vitrification is
> > the way.  Perhaps if I studied it more, it would work for me.

Vitrification is not trivial to control. But when it works, it works
very well.
 
> Actually, the damage from freezing is dehydration of the cells.  Ice

There are several damage mechanisms.

> forms outside the cells, pulling water out and the salt concentration
> reaches damaging levels before the concentrated salt solution freezes.
> 
> This is all fairly well understood because because human embryos are
> routinely in cryoprotective solutions, cooled to LN2 temperature and
> later revived for implantation.  Tens of thousands of examples walk
> the streets.
> >
> > Wasn't it you who commented about creating room below the brain cavity to
> > allow a bit of expansion?
> 
> No.
> >
> > In keeping with my earlier notion of cryonics as a marketing task, it would
> > be a Good Thing if you could tell your clients you know how to keep them
> > from cracking.
> 
> We don't.  We have a choice of being honest and saying what we are
> reasonably sure about, and what we don't know how to do, and lying.
> If this conflicts with marketing, too bad.
> 
> I don't know if cracking can be solved or not.  It's partly an
> engineering problem and partly an economic problem.

Cracking is largely solved by intermediate storage (Brian Wowk).
I think it is largely a cosmetic problem. I don't see how anyone
would expect that cryopreserved patients would be be rewarmed
as is, if at all.
 
> I can go into details if enough people are interested.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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