From: Robert J. Bradbury (bradbury@www.aeiveos.com)
Date: Fri Oct 22 1999 - 06:38:58 MDT
On Thu, 21 Oct 1999, Spike Jones wrote:
>
> If we are concerned with the Radioactive decay for cryonic preservation
> (now that I think about it, I believe it was Robert Bradbury that started
> this thread)
Me?!? I thought I was responding to one of your comments!
Although this does follow from the dicussion back in August where
were were discussing the radiation damage resulting from supernovas.
> then we also need to think about what effect typical ionizing
> radiation has on matter at liquid nitrogen temperatures.
Well, at LN2 temperatures you don't have very much chemical reaction
taking place, so what will happen is the accumulation of "unusual"
molecules. They will not be very different from the molecules that
are normally found in the body (after all are exposed to radiation
every day) but they will accumulate to higher levels than we normally
encounter.
> The potassium
> decays would be predominantly in the skull, the bony material having
> much more patassium than the brain itself.
Actually in the brain you presumably have a high K level in solution
since the neurons pump Na/K in and out to fire the neurons. I'm unsure
whether cerebral-spinal fluid has a higher K concentration than blood
in general though.
> I think that radiation would be of little consequence in comparison to
> the transmutation of elements resulting from beta decay. spike
As I showed in my discussion regarding DNA, you can probably tolerate
a fair amount of transmutation (C->N) and since K goes to Ca that
isn't going to hurt anything. Since the biological effectiveness
of alpha radiation is so much greater, I'd put my bets on that
as being a major player. But we need to know in fine detail the
quantity of various radioactive isotopes in the body, their
decay paths, the molecules they are in, etc. to know exactly
what the downstream effects would be. Most of the C is in proteins
and not in DNA and so the 14C decay may have more significant
consequences for enzyme function than it will for DNA preservation.
Robert
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