On Thu, Dec 18, 2014 'Chris de Morsella' via Everything List < [email protected]> wrote:
> Water expands when it freezes; Yes. > Until a method of preserving the exquisite micro (and possibly also > nano-scale) structures of the brain are developed freezing an organ > destroys it. Freezing will certainly destroy the functionality of my brain no doubt about it, but there is a far more important question, will it scramble the information on how the atoms in my brain were arranged before it was frozen so profoundly that even advanced nanotechnology can't recover it? Even functionality has been preserved in the case of human embryos frozen in liquid nitrogen and they contain millions of cells; granted that still vastly smaller than a human brain but still it gives some reason for optimism. > Certain species can freeze and thaw back out and be fine, but they have > evolved blood containing anti-freeze in it > And Alcor will infuse my brain with a cocktail of anti-freeze agents, the same sort of agents that are used to protect human embryos from minus 320 degree temperatures, except that Alcor will use much higher concentrations so my brain will not freeze but will undergo a glass transition process and vitrify. > (which is highly toxic to humans by the way). > Yes when anti-freeze agents are used in high concentrations (as Alcor does) they are highly toxic largely because they denature proteins, that is to say they change the way the sequence of amino acids fold up to form the protein, and the shape a protein folds up into determines how it functions. However the sequence of amino acids does not change so although the protein no longer works the information on what the shape the protein was in before it was denatured was not destroyed. > I do not see how the trillions of ruptured cells (from the micro-shards > of ice) With cryoprotectants that shards of ice business isn't much a problem but severe dehydration of cells is real and would totally destroy functionality, but as I said resorting functionality to that frozen block of protoplasm isn't my concern, preserving the information in it is. > constituting the resulting thawed mush of what once had been a > functioning system with trillions of parts can be put back together. First of all I'm not interested in what happens during thawing, I'm only interested in what happens during freezing because I'm only interested in preserving information. The key question is will my brain enter a turbulent state when it is frozen or will the flow be laminar. If it's turbulent then small changes in initial conditions will result in large changes in outcome and I'm dead meat, even nanotechnology couldn't put Humpty Dumpty back together again; but if it's laminar figuring out what things were like before they were frozen would be pretty straightforward. Fluid flow stops being smoothly Laminar and starts to become chaotically turbulent when a system has a Reynolds number between 2300 and 4000, although you might get some non chaotic vortices if it is bigger than 30. We can find the approximate Reynolds number by using the formula LDV/N. L is the characteristic size we're interested in, we're interested in cells so L is about 10^-6 meter. D is the density of water, 10^3 kilograms/cubic meter. V is the velocity of the flow, during freezing it's probably less than 10^-3 meters per second but let's be conservative, I'll give you 3 orders of magnitude and call V 1 meter per second. N is the viscosity of water, at room temperature N is 0.001 newton-second/meter^2, it would be less than that when things get cold and even less when water is mixed with glycerol as it is in cryonics but let's be conservative again and ignore those factors. If you plug these numbers into the formula you get a Reynolds number of about 1. 1 is a lot less than 2300 so it looks like any mixing caused by freezing would probably be laminar not turbulent, so you can still deduce the position where things are supposed to be. Actually to my mind the most serious obstacles to the success of my program are not scientific at all, they are these: 1) Will my brain really be frozen soon after my death? 2) Will my brain remain frozen until the age of nanotechnology? 3) When it becomes possible to retrieve the information in my frozen brain will anybody think I'm worth the trouble to actually do it? Concerning that last one, I think it will either be impossible to do so or cheap and easy to do so, the time when it will be possible but expensive to revive me will be very short. I'm willing to concede that my value to a Jupiter Brain will be almost zero, but my (perhaps hopelessly optimistic) hope is that it is not precisely zero. Given a choice between no chance and a slim chance I'll pick a slim chance every time. > > In the case of John Clark's brain... he won't care that the information > encoded in his brain has just been destroyed by the process -- he paid 80 > grand for -- meant to preserve it... because he will have died (and won't > miss that 80 grand either I guess) > If cryonics doesn't work I'll never have any regrets about doing it because I'll never know it didn't work, and If it doesn't work I won't be one bit deader than you will be who took a more conventional approach and had your brain rot in the ground or be burned up in a furnace. 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