[extropy-chat] Alternative to CryowasTheAmazingCellularRepairdevice

[Eugen Leitl]

On Mon, Oct 17, 2005 at 09:37:33AM +1000, Brett Paatsch wrote:

> >You were put together in exactly a Lego block fashion.
> 
> Lego block construction proceeds with the construction tools
> (the kids hands) outside the block. And the instructions/design
> decisions about what will be build also outside the block (in the
> kids head). The lego blocks don't grow and divide steering
> themselves down developmental paths (as cells do), construction
> proceeds with the lego blocks being snapped in discretely to the
> outside of the first block that was laid down.

All accurate objections. But making copies of objects from
biological tissue glass at cryogenic conditions is something
else than weaving a live critter into being on a nanoscaffold
loom. That one is so much harder than one has to deposit
a vitrified critter around the scaffold, and flash-defrost it
into life. (Again, this is a ridiculous scenario I'm describing
just for the sake of what is possible in principle).
 
> Nature in growing Spike had the advantage of not caring about
> what particular Spike (Spikes neural structure and memories) in
> a range of possible Spikes would emerge as a result of the dna
> instructions meeting extracellular environmental stimuli. Nature
> wasn't trying to reverse engineer a particular Spike it was just
> getting on with building an original from a make-something-like
> -a-Spike genetic instruction set in the dna formed when Spike's
> mum and dad's dna got together.

Yes, nature does something different. We're not nature, so we're
taking a different approach, to achieve something else (nature
doesn't deal with resurrection nor immortality for higher organisms,
for instance).
 
> If you were going to use Drexlerian nanotechnology to build the
> cellular structure of Spikes brain you'd be trying to building lego
> block fashion using atoms as your base construction element not

Not atoms, just precursor feedstock.

> cells. But to recreate Spikes brain in flesh (and get Spike back)
> you would have to create a whole lot of cells (trillions of them)

You recreate structure. That it describes cell at some pretty
high level is implicit to the replication process.

> capable of functioning as the massive specific concert of cells
> that was biological Spike. And you'd have to create them on
> location because you couldn't move them past each other as
> assembled cells. Their shapes which are interlocking wouldn't
> allow that.

Of course. You can assemble blocks of them convergently, however.
 
> To build lipid layers of cells on location without using water
> chemistry (which you couldn't because of the temperature
> constraint, water doesn't act like water when its ice) you'd be
> placing molecules of lipid with nanobot tweezers. A broken
> lipid cell membrane (width 6 nanometres) means a non
> functional cell or cellular compartment and it would certainly
> mean non-functioning mitochondrion in the cell.

So, don't make holes into lipid bilayer membranes when nanoprinting
them. (Actually, preassembling whole mitochondrions and using them
as a building block is a good idear).
 
> It would take too long (I don't know how long but perhaps
> age of the universe timescales) to construct like this unless
> you had a massively parallel construction operation going

How else do you expect this could be done? Of course you
have to use massive parallelism. If you're limited to surface
work, this means convergent assembly. There is no other way.

> on. And you can't do that because there isn't space between
> the being build cells for your nanobots that are having to
> place molecules to less than 6 nanometre precision to get
> functioning cells.

No. See convergent assembly. Besides, no-one suggests you
nail down the entire structure from the atom tacker, nail by nail.
This is a bit like manicuring your golf course with nail 
clippers.
 
> All of which happens in a watery chemistry environment (important
> for causing the proteins made up of amino acids to take the three 
> dimensional
> shapes they do and for lipids to arrange themselves as they do) inside the 
> cell
> at  temperature of around 37 degrees. Much away from 37 degrees and the

The prefolded protein at 77 K or below is a hard brick, and can be easily
inserted as a whole before being cemented with water in place. Very much
like bricks, mortar and trowels. Very small trowels, of course.

> I'm effectively certain that they wouldn't try to.
> 
> But that was the scenario Spike was musing over, he wasn't musing over
> uploading (a separate thing with its own problems) he wanted his brain
> back in a new buff body.

And a habitat for life-support of that new buff body, no doubt. Sure,
if he wants to be a live exhibit in the zoo. (And if there are zoos.
Solid state culture, mumble. Rendering a fake is so much more cost-effective
that building a huge honking real thing, and the real thing is so *glacially slow* 
it bores you to virtual tears. A bit like watching the glacier front
receding due to climate change).
 
-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a>
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ICBM: 48.07100, 11.36820            http://www.leitl.org
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