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Hello! I'm just a medical student myself, but here's my take on this:

Your lungs operate on the principle of differential pressure. During normal breathing, hen the pressure inside your lungs becomes less than that of the surrounding atmosphere, air rushes in to normalize and fill it until they are again equal pressures. Gradually increasing or decreasing the pressure of the atmosphere around you (as on a plane or while diving) does not change the physical difficulty of breathing. It may slightly alter the diffusion coefficients of gasses passing through the membranes in your lungs, but this effect is mild at the pressures you could attain in an aircraft hull (and toxic at higher pressures! [0]).

For this reason, you'll notice in images of people in iron lungs, their heads are outside of the device. This allows those who cannot create negative pressure (due to damaged or paralyzed diaphragms or ribcage muscles) to follow a different path. The pressure outside of their chest becomes lower than that experienced in their lungs, forcing an expansion; in order to breath out, the pressure in the chamber is increased. In an aircraft hull a person's lungs/trachea/mouth would be exposed to the same pressure as their chests.

This of course does bring up the very valid question: What happened to all of the iron lungs after the decline of Polio?

[0] https://en.wikipedia.org/wiki/Nitrogen_narcosis

EDIT: Oh I realize I didn't fully discuss the possibility of using a plane as a hyperbaric chamber [1]. The constraints around this concept also rule it somewhere outside of what I would consider feasible. Aircraft typically use bottled oxygen (I believe the 737M does) or a chemical generator, neither of which can produce continuous oxygen or fill the entire plane with it to high levels [2]. If you were able to outfit patients with individual tanks (which would also have to accommodate for increased pressure), the gains seem mild at best compared to 100% O2 in a hospital setting. Fick's Law for the membranes in your lungs is roughly

Rate of diffusion = (Area * Solubility of gas * concentration gradient) / (membrane thickness * sqrt(molecular weight of solute))

The factor that increasing pressure would modify is the solubility of the gas, which according to Henry's Law [4] is directly proportional to pressure. At absolute best (100% O2 on the plane at 2atm), you could expect to get 2x improvement in blood oxygen saturation. Unfortunately I don't believe the breathing issues that are being described can be overcome by this strategy. It's an incredibly creative concept though!

[1] https://en.wikipedia.org/wiki/Hyperbaric_medicine

[2] https://en.wikipedia.org/wiki/Emergency_oxygen_system

[3] https://clinicalgate.com/gas-exchange-between-air-and-blood-...

[4] https://en.wikipedia.org/wiki/Henry%27s_law

The relationships and high-level effects are maintained in our body of literature. It's hard to resist wanting to put it all in some sort of megachart, but even the pathway diagrams vastly simplify the real interactions. The reason they don't seem to connect substance and effect is because often the substances are very far removed from effect, or may not lie on a known pathway at all.

It's still very much a "we don't know what we don't know" situation, which is both intimidating and exciting. There's a lot to be done before our models are even adequate, but we at least get to be part of that learning process.

The short answer here is yes. We're constantly working to get more complete models, but surprisingly big effects can come from surprisingly small pieces of the puzzle. We still don't even really understand how Tylenol/Paracetamol/Acetaminophen works!

A great example of the gap between our current models and what would be sufficient comes from the COX-2 inhibitors (Vioxx/Celebrex). Ibuprofin (Motrin/Advil) and other NSAIDs modulate both COX-1 and COX-2 receptors in the body to reduce inflammation, but inhibiting COX-1 also causes stomach damage. The early COX-2-specific inhibitors were designed from the ground up using our best models, which were thought to be well-understood. Unfortunately, after several years on the market, it was discovered that this also came with a large increased risk of heart attacks and strokes.

The body just has so so many moving pieces, and while we're getting better, it's going to be some time before we are able to base these studies entirely on theory, and when we get there we'll be able to skip the mice entirely!

Hey, I remember this project! I had the chance to give a bit of advice to the creator, Zach Scholl while I was working at Duke's Co-Lab [1]. It was cool then, and looks like it's only improved in robustness since (and it sounds like HN has plenty of ideas for PRs).

Although I no longer work/learn at the Co-Lab I'd love to plug the value of these sorts of programs at schools. They give encouragement with money and publicity, and most importantly, tools (VMs/APIs) and advice ("why won't this compile?"/"where do we start?"). I had a chance to see and help with a lot of projects that wouldn't have otherwise been possible to get built. Hopefully it helped a few people get into hacking that wouldn't have otherwise too!

[1]: colab.duke.edu

One big limitation that was glossed over in the presentation is radiation exposure. The only time it came up was the mention of a 'solar storm shelter'. The radiation exposure during the Martian transit would be much greater than the same time spent on the ISS, somewhere on the order of 200mSv [0] (the composition of this radiation also contains significantly greater proportions of heavy-ion radiation, which appears to be more damaging, so this may need to be adjusted upwards). According to the wonderful xkcd chart [1], this would be in the 'probably no radiation sickness, but certainly not good for you' territory.

I would love to know what their plans are, since shielding is heavy. [2] seems to suggest electromagnetic deflection as viable (which would be insanely cool, and could probably reuse SpaceX's cryogenics work for superconductors).

Also, a quick search didn't turn up much on the anisotropy of interplanetary radiation, but I wonder how much a reduction would be achieved by angling the crewless area of the ship towards the solar wind (which I think Musk had touched on in an earlier talk).

[0]: http://www.srl.caltech.edu/ACE/ASC/DATA/bibliography/ICRC200... [1]: https://xkcd.com/radiation/ [2]: https://engineering.dartmouth.edu/~d76205x/research/shieldin...

EDIT: Of course these sorts of talks are really exciting! This is just one more in a laundry list of crazy-cool engineering problems that have to be/are being solved.

At my University, where I both worked and studied, we had a second semester senior post his automatic registration script to the school's Facebook group. This sent up alarm bells and I sent emails to warn the appropriate people, but it was the night before registration. The load immediately and totally crushed the system, and registration had to be rescheduled. They switched around some tags on the page (the script did very fragile webscraping), and that was enough that there were no more issues. The student had to fight an academic misconduct trial for it as well. A painful situation all the way around.

Perhaps "prejudiced" might be an appropriate substitute for the situations that you're thinking of?

Last year I was able to play with one for a couple of hours. The most impressive and exciting part for me was that it wasn't bad. I don't know about others, but I had expected an unpolished feel, and to be continuing to say "oh this will be great when they ______". The latency is much lower (comparable to modern VR) than I expected; the occlusion of virtual objects by real ones works surprisingly well, even with weird shapes; even the gesture recognition worked well. My overall takeaway was that it was much further along than expected. It was genuinely fun to play with, and I felt able to walk around my office while wearing it. Obviously the FOV is an issue to be worked on, but overall I was just impressed. I wish I still had one I could play with.

It depends highly on the mechanism of carcinogenesis. Lead is a (possible) carcinogen, and accumulates even in relatively small quantities because it takes up residence in your bones and is slowly released back into your blood over years. Others may be eliminated rapidly and only cause damage in large or continuous doses. Frustratingly the answer is often "it depends". The very low end of the spectrum of exposures is often the most relevant to humans (due to our relatively low exposure to most things), but very hard to study, because the effects are often drowned out by other causes of morbidity/mortality.

In a side note, Organophosphates replaced Organochlorides for a very similar reason. They have a much faster elimination rate, reducing the time that they stay in the food chain (and hopefully reducing the exposure of non-target species). Organochlorines, on the other hand, were very stable, which made them easily stored, but also caused biomagnification, where animals further up the food chain started concentrating it in their bodies as they ate smaller animals that had been exposed. This caused serious environmental effects, leading to the shift to the pesticides we use today.

Just for reference, I've been doing this for a few months now. I'm not sure what's changed, but you'll need ubuntu 16 (you can uninstall 14 and reinstall WSL to get it) in WSL to do it.

What a great thought! I was having trouble justifying it myself, so I asked someone else around the lab. They pointed out the very important reason for doing a twin study (as opposed to just following them longitudinally like you're suggesting): you can identify effects that were "going to happen anyway". Sure, we might send them both up and see that they both experienced changes, but we wouldn't know whether this was simply due to genetic predisposition. By comparing the twins side-by-side, the goal is to rule out genetic contributions. Of course, this is difficult with such a small study group, but it represents the start of hopefully a larger set of data.

Your point is still important, whether or not it is valid, because it represents a not-uncommon sentiment in the public. It's up to many researchers to try to make the results and potential of their work accessible to the public. The best mentors I've seen are always able to transfer their own excitement for their work to others.

While "as safe as possible" is certainly the goal, most of the research is centered around first clearing the low bar of "safe enough to even make it there and then do some science". "Earlier death" might mean "on the way to mars", which would end up being a much bigger waste of money and effort (to say nothing of the political capital). Those are the questions we're trying to answer right now.

The other side of these things is that the research being done is not single-purpose. The lunar missions were an amazing human achievement, but their lasting legacy can be seen much more clearly on earth. Our radiation work has homeworld implications for understanding radiotherapy. Heavy ion therapy is a rapidly emerging technology that has the potential to make some previously-mortal cancers tractable, and understanding its full biological effects is critical. By exploring new worlds, we hope to be able to improve the lives on our own as well.

In orbit there is still the significantly protecting effect of the Earth's magnetic field, which deflects much of the heavy ion radiation. This more massive radiatiom has different mechanisms of damage, and we're finding that it is likely more damaging in many contexts. So all-in-all, the space station ends up being a minor simulation of the much harsher interplanetary environment. I have several theories about how musk's team intend to solve this issue, mostly talking about surrounding the crew quarters with water. That being said, this problem is still largely unsolved and remains one of the biggest barriers to interplanetary human spaceflight.

I think that's a great insight. At the very least, it gives us more points of comparison. I'll try to pass it along to those who might be able to do something with it! (And now I'm going to go down the rabbit hole to find out if there's been anything like that done before)

Okay the rabbit hole wasn't that deep. At the very least it appears that this [1] is ongoing.

[1] https://www.nasa.gov/mission_pages/station/research/experime...

Hey everyone! I work in a lab that studies the effects of interplanetary space radiation (NASA Grant), and we were actually discussing this study yesterday. While the data from this study is a wonderful first step forward, there has been a decent amount of criticism, because n is essentially 1 (with 1 control). This makes it very difficult to separate the inter-twin effects from the space effects.

If there is anything that you feel that we should be focusing on or any aspects of space radiation that haven't been properly explored, we're always looking for new ideas!