X-Message-Number: 4690 From: (Brian Wowk) Newsgroups: sci.cryonics Subject: Re: Rebooting a suspendee Date: 29 Jul 1995 23:02:06 GMT Message-ID: <3veele$> References: <> In <> (Anders Sandberg) writes: >Have anybody found a solution to how to "reboot" a >suspendee after having the body repaired? In the most >detailed schemes I have seen, we let nanomachines >survey the body and the rearrange and repair it while >frozen. But how to thaw it without any additional >damage? Rebuilding it at room temperature is probably >not a good idea, since different parts will begin >to move around in a most complex way, from the >cellular level and up. I'm wondering what "detailed schemes" you have seen, since most of the ones I'm aware of (even Drexler's 1981 PNAS paper) do deal with this problem explicity. Solutions include: a) Selective blocking and unblocking of enzyme active sites to inhibit unwanted reactions during the rewarming phase. b) Crosslinking everything in place until rewarming is complete. (Leaving the crosslinks in place after rewarming also gives the option of true room temperature biostasis.) c) Continuous repair and reversal of unwanted reactions on the way back up. This is conceptually equivalent to progressive "redesign" of your metabolism so that it is optimized for operation at whatever temperature you are at-- essentially what Drexer meant in his PNAS paper when he spoke of "modifying metabolism to resemble that of freeze-tolerant species." Look, in the worst possible case, once you are repaired we can use rf heating to take you from -130'C to body temp in a matter of minutes (the approach now being used by organ preservationists to avoid devitrification and cryoprotectant toxicity in cryopreserved organs during rewarming). That leaves at worst a few minutes of ischemic injury to fix. To summarize: Taken in the context of the difficultly of the overall repair problem, the rewarming problem is TRIVIAL. This should be obvious after the most modest amount of thought. >This is of course yet another argument in my opinion >for uploading - Aye, and there's the rub. I don't think you gave this problem much thought because you simply saw it as an opportunity to post some uploading propaganda. Forgive me, but after years of being told that cryonics is obsolete and uninteresting because we are going to have uploading *real soon now*, I'm starting to develop a real disdain for uploaders. I do agree with you, though, that uploading (when it becomes available) will mostly likely be done with the brain in some kind of biostasis. This is of course yet another argument in my opinion for cryonics. :) ---Brian Wowk Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=4690