X-Message-Number: 17759
From: 
Date: Sun, 14 Oct 2001 04:20:41 EDT
Subject: Size Matters

William Gale:

You identified the other significant visual difference between the species of 
lichen that I found and used and the photograph of the lichen specimen on the 
web site.  There is not the obvious hollowed out area/structure on the 
species I used, otherwise it appears to be a pretty good match--and certainly 
the best match of any of the photos I could find there, by far. Yes, you are 
about right on your estimation of the thickness of the stalk.  Actually the 
tallest of the stalks do extend to almost a centimeter, whereby the thickness 
of those stalks may be on the order of one and one-half millimeters.

You say:  "I believe the maximum thickness of a whole plant
or animal frozen to LN2 temperature would be an interesting number 
to watch for progress."

I agree completely.  My guess is that the *mass* of the specimen will be key 
to reanimation in the type of experiments that I am currently doing; and is 
probably more important than the complexity of the specimens' neural 
system/"brain" in the case of animals (e.g., insects & small aquatic 
creatures, etc.) 

William, you are likely versed on all the following, but for neophytes to 
cryonics and/or "bio-cryogenics," )as is a more appropriate "word" in this 
case,) I will elaborate:

*Thawing dynamics* appears to be the major issue here, where rates change 
exponentially with the size of the specimen due to inherent and significant 
differences in surface to volume ratios.  Increases in surface area are 
mathematically squared where increases in volume are cubed.  Both cooling and 
warming rates of a body/mass are a direct function of this ratio.  "System 
heat dissipation" is an entire sub-branch of science and technology (very 
much so including microtech and nanotech.)  Of course, thawing dynamics are 
related (to dissipation) but are actually an entirely different concern, and 
schemes for manipulation are distinct. Unfortunately, the best I can tell, we 
are on our own here.  Right now thawing dynamics are probably not very 
relevant to anything other than the final stage of cryogenic organ 
preservation (and later on, perhaps cryonics).

"Uneven or delayed thawing" from the periphery to the innermost parts of a 
specimen is the case but does not adequately define the concern.  It is the 
*slow thawing* (of any vital section of the specimen) that is killer.  Slow 
thawing means deleterious ice formation/growth as the inner sections rewarm 
(more slowly).  It is more a gradient temperature change over time rather 
than the more instant change for outerlying cells/tissues. This problem is 
obviously exacerbated as the mass of the specimen increases; and even if the 
specimen is small enough to nearly completely vitrify on "freezing" (again 
due to the favorable surface to volume ratio of a smaller specimen), heat 
always exits faster when dunked in LN2 than it reenters after being removed 
from LN2.  Of course, removing it and immediately redunking in a stream of 
warm water, rather than room temperature air, would almost certainly help so 
long as you did not drown the subject (which is a very real concern even for 
insects).  Hot water would be even better, but we do not want to cook the 
subjects!

I look forward later on to attempting to encourage marginal specimen-types to 
reanimate where they otherwise would not by attempting to unify, but more 
importantly, quicken, interior rewarming (e.g., instant pressure release, 
microwave and ultrasound techniques, etc.).

You write: "Does anyone have references to the freezing of whole insects 
or vinegar eels?"  I do not but would like to have them.  I know that 
nematodes have been successfully reanimated from LN2 (see last issue of "The 
Immortalist.")  They are about the size of mosquito larvae.  By the way, 
mosquito larvae are top on my hit list.  Count on a report from me next 
mosquito season (tadpoles would be well advised to make themselves scarce the 
following year.)

Now it's time to see if I can figure out how to download and listen to the 
interview of Robert and James by Dr. J.

D.C. Johnson

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