More thoughts on life-extending nanotech
Posted: 1/17/2001 4:46:28 PM
By: Comfortably Anonymous
Times Read: 1,689
0 Dislikes: 0
Topic: Nanotechnology, Quantum Physics, Etc.
Parent Message
I agree with a lot of the things you said, but I'm going to point out a few discrepancies:

Definitely there is deterioration-based aging. But most of this is caused by data corruption of the DNA in each cell. With each replication, a small amount of DNA data is not correctly replicated, due to things like Brownian motion, current chemical conditions in the cell at the time of replication, subatomic particles knocking a piece of data silly, etc.

However, the replication limit is not completely true. Most cells instead have conditions on when they replicate, which is part of the instructions in the DNA, otherwise every organ/bone/etc in your body would continue to expand, crowding out the others. Your brain would pop your skull eventually if it kept freely replicating.

However, theories like once your brain is fully developed, you never get any new brain cells, have been disproved. Same with the theory that your living brain cells are the same age as you. Instead, they have found that brain cells will 'die of age' or from injury, but then that re-invokes the replication trigger and enough are then replicated to fill the void. But just brain cells regenerating is not always enough to restore everything after a severe brain injury. In some places, it is replaced with non-processing scar tissue, and in other places the number of cells regenerate to the original level, but don't reconnect in the same pattern that the originals were, thus some memories are knocked out permanently. However, the new cells will be able to connect in new patterns as your brain records new data.

Heart cells will regenerate, but usually they are killed by oxygen starvation which then triggers scar tissue cells rather than heart cell replication.

Drexler's idea is good, and could be true, but I don't think that it would need to be a nanobot in each cell. I envision more of a concept where there is a 'mothership' nanobot that cruises the bloodstream and then attaches to the cells in a similar way that virii attach to a cell and inject their DNA-modifiers. The actual injection of the virus material is not what kills it, it's when the virus completely overrides the self-preservation processes of the cell and makes it completely concentrate on replicating the original virus until the cell walls break down, thus killing the cell. There are indeed some viruses that do not destroy the cell, but just lightly consume the cell resources.

But back to the point, mothership would 'inject' a probe appendage into the cell then doing something analogous to computing a hash value of the entire DNA strand to find out if it needs to go through and compare the cell's DNA to a copy of healthy DNA to find what is incorrect. It could then analyze the changes and make a decision whether the damage can be repaired, or if it instead should terminate the cell to prevent it from replicating with bad information, such as what happens with cancer cells - originally good information in the cells with a data error caused either by damage received from the environment or bad information in the original cells.

The copy of DNA in the mothership is the key. And how to get the original copy in the first place? Possibly two (or more) ways: You could harvest some DNA from a person when they are young - before much damage has occured. You would probably want to take a number of samples, (10,000 cells or so) do a comparison of the DNA of each cell against the others to make sure you don't make your master copy from a damaged cell, and then you have your master copies. Whether that should be stored biologically, or stored on a computer (with a lot of cross-checks to insure data integrity) will be something else to research. Another way would be simply to have the mothership store the 'hash value' of the DNA in the cells in encounters, possibly in a queue-type setup of hundreds or thousands, where the first samples in the queue will get pushed out/erased as the queue fills with new samples. And also comparing the samples against the other samples to invalidate samples that do not match the majority of the other cells, so that progressive degradation does not occur. Then the 'known-good' value deduced from the sampling will also be compared against the copy of the master copy that the mothership is carrying to ensure that the copy has not been corrupted. If the copy is corrupted, then it needs to be researched whether it would be better to have the mothership destroy itself, replace the copy with the DNA from a known-good sample, or something else. Also, when motherships encounter each other in the bloodstream, they could also compare their copies against each other. However, since it would not be definite which one (if either) is carrying a correct copy, perhaps using something similar to the moderation system here on .5e could be implemented: The motherships would have a 'counter' type thing, if two motherships 'disagree' on their copies, then a point is subtracted from a counter. If the counter reaches zero, the mothership terminates itself, as if a large number of comparisons fail, then that mothership near definitely has a corrupt copy and will do more harm than good. Possibly also a point booster for each comparison that succeeds. Small change of progressive degradation occuring here as occasionally motherships will encounter each other that are both corrupted, so to counter that, also have a max lifetime of each mothership, when past, the mothership destroys itself.

What about people with genetic disorders that will eventually kill or disable them? In that case, it depends on us discovering the patterns/sequences for each of these, the searching the original master copy for these sequences, and patching the master copy with to fix these sequences.
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