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What happened to regrowing limbs? From what little I understand, with pluripotent stem cells we could do a lot, except cancer.
Why don't we use stem cells instead of drilling for cavities? While there are a few types of tissue, tumors are fairly rare in teeth, likely due to minimal blood flow.
In general the human body is only capable of healing injuries that are the kind of thing that, if they were smaller, would still leave the victim alive, in the Stone Age. If an injury is of a type that would be immediately fatal in the Stone Age, there’s no evolutionary pressure to make it survivable. For example, we can regrow peripheral nerves, because losing a peripheral nerve means a numb patch and a weak limb, but you could live with this for a few months even if you’re a caveman. On the other hand, we can’t regrow spinal cord, because a transected spinal cord is fatal within a day or two even given the finest Stone Age nursing care (it didn’t become survivable until about 1946.). On the third hand, we can heal brain from strokes, even though brain is more complex than spinal cord, because a small stroke is perfectly survivable as long as you have someone to feed you until you get better. We can survive huge surgical incisions, even though those would be fatal in the Stone Age, because small penetrating wounds were survivable, and the healing mechanisms can just do the same thing all along the incision. This is why we sew wounds up: to convince the healing mechanisms that it’s only a small cut.
Unfortunately this argument suggests regrowing limbs is impossible. An amputation is bad but survivable, and after it heals, you can still get around. But many years of spending a lot of bodily energy on regrowing a limb that is pretty useless for most of that time doesn’t seem worthwhile.
Some particular problems I see:
In humans, there’s no mechanism for a growing limb to connect correctly to an adult injury site. For example, there’s already a bunch of scar tissue there, which has to be cleared away progressively as the limb grows. Evolution has not seen fit to provide us with this complex biochemistry, unlike the case of salamanders.
Children have a high level of circulating growth hormone, which tells the arm cells how fast to grow. If you tried to provide this to an adult, their other bones would also grow, causing deformity (acromegaly).
It’s odd that we can’t grow new teeth when the old ones fall out. More than once, I mean. Drilling for cavities makes sense because the enamel (outer tooth layer) is essentially dead, and doesn’t regrow. But we should be able to grow a whole new tooth from the root when we get a cavity.
The regrowing limb thing is a nonstarter due to the issue of time if I understand correctly. Salamanders that can regrow limbs take roughly the same amount of time to regrow them as the limb takes to grow in the first place. So it would be 1-2 decades before the limb was of adult size. Secondly it's not as simple as just smearing on some stem cells to an arm stump. Limbs form because of specific signalling molecules in specific gradients. I don't think these are present in an adult body once the limb is made. So you'd need a socket which produces those which you'd have to build in the lab, attach to blood supply to feed the limb, etc.
For a good few years you'd have a tiny baby limb, which would make it impossible to have a normal prosthetic. I also think most people just don't want a tiny baby limb attached to them. I don't think growing it in the lab for a decade is feasible for a variety of reasons. I also don't know how they planned to wire the nervous system in, or ensure the bone sockets attach properly, or connect the right blood vessels. The challenge is just immense and it gets less and less worth over time it as trauma surgery and prosthetics improve.
There seem to be clinical trials underway for regrowing teeth in Japan: https://www.popularmechanics.com/science/health/a60952102/tooth-regrowth-human-trials-japan/
DOGE.
This is an opportunity to work with the levers of real power. If there are 5 people here who work on this for two years, that's an in with Senators, Congressman, bureaucrats and possibly Musk.
Just showing up and making connections while doing hard work is the most efficient way to get power right now, in the time before AI gets dangerous and power will be very relevant.
I do not believe that this should be taken as an opportunity to evangelize. People, not ideology.
This seems like something worth funding if someone would like to but can't afford it.
Why aren't research companies made in Africa/Middle East/China for human research- cut out most of the bureaucracy and find out fast if something works, if it does set up a company in a 1st world country to go through the steps?
Research companies work best when there's plenty of infrastructure that can supply stuff they need to do the research. Including, to mention one recent case, electricity. It also helps to be in an area where there is stable government that can protect the research site from civil or military unrest, and too much (or too unpredictable) corruption. You also want it to be a place where your researchers are happy to live while they do their research, and where you can relatively easily recruit other skilled workers.
China does meet these requirements, but it is not exactly lacking in bureaucracy so I'm not sure why it made the list. If you're doing research involving human trials of some sort, you also want to be able to communicate well with the participants so extensive knowledge of the language and culture will be very useful.
All that said, plenty of organizations do carry out research all over the world, not just in rich countries with a lot of bureaucracy.
Speaking as a low-level employee in the medtech industry, I can report that a lot of companies are satisfied doing human research in Eastern Europe, where costs are low and regulations lax, but infrastructure is still available. I have heard that there is a bit of "rotation" among these countries over time, since costs and regulations tend to increase wherever human research becomes popular.
Devops Mentality is correct:
Friction is a big deal.
Being able to change code and deploy immediately (or in a few minutes) matters immensely.
This might just be feedback loops at an extreme, but I believe it's something more.
The benefit of going from 20wpm to 40wpm was not ×2 to my writing and experience, it was more like ×8. I fully intend to reach 60wpm.
It was closer to a ×2 to my developing experience, which is interesting as most of software development isn't the actual typing. Another anecdote is that the best programmers I know all have 60+wpm (there was one react front end guy who was good, but mostly at design).
Reducing friction is underrated, even if friction is only 10% of a job (typing during coding), improving that friction substantially matters more than 10%.
This may have to do with flow, concentration or enjoyment
University education can be made free pretty cheaply.
The cost at scale is in the credentials- you need to make tests, test students, and check those tests.
The classes can be filmed once, and updated every few years if necessary. Each course can have a forum board for discussion and meeting up for studying in groups.
See course credentials for things like AWS.
Whether something is technically and economically possible is just a part of the puzzle. The remaining part is whether the people who make decisions have the incentives to do so.
According to Bryan Caplan, schools certify: intelligence, conscientiousness, and conformity. Online learning would certify intelligence, conscientiousness (even more than school attendance), but not conformity. Would the employers be okay with that?
Also, some prestigious universities select for having tons of money and/or the right social connections. The education is not the point. The point is that your parents had to be a part of the social "inner circle" to get you to the university, and you spent a few years socializing with other kids of the same kind, establishing the "inner circle" of the next generation. Making the credentials available to hoi polloi would defeat the entire purpose.
There is a beautiful thing called unilateral action.
I believe most employers mostly don't care about conformity as such.
The inner circle stuff is only true of elite schools AFAIK. You can outcompete the rest of the universities