That's my concern - I can't find any evidence of *any* awareness by mission planners as to this issue.It's not just about depression, either:https://en.wikipedia.org/wiki/Deuterium-depleted_water"Experiments have shown that consumption of light water may be beneficial as an adjunct to chemotherapy. A 1999 Romanian study found that water with only 30 ppm deuterium produced marked improvement in survival rates of mice bombarded with ionizing radiation.[3] A study of four patients with brain metastases from lung cancer found a three-month regimen of light water "noticeably prolonged" their survival time.[4] A 2010 Hungarian study found significant improvement in the survival times of prostate cancer patients treated with light water.[5] Despite Gilbert Lewis' call in 1934 for such experiments,[6] research on the effects of deuterium-depletion on living cells has been very limited with less than a dozen peer-reviewed research papers available via PubMed in mid-2011[7]"The lack of study on the issue that they mention matches my experience in digging up information. The existing research points to a significant potential problem here - depression, radiation vulnerability, susceptibility to cancer, etc all seem positively correlated with deuterium levels. Yet it seems to just be flying under the radar.There are solutions. But is anyone paying enough attention to incorporate them?
I'm a neurobiologist in my day job. I can assure you that all of the papers you linked to/cited are in journals nobody takes seriously or bothers reading. Basically nobody has properly looked at this, but from basic biology, there is no reason to assume there would be any effect of deuterium depletion, and very limited effects of increases, which are only significant in vastly higher fractions.
It's a potential export item, too, if you can get your transport costs down enough. Of course, Venus is even richer in deuterium - the ratio there is just crazy, like 1,2% in the habitable zone. But Mars presents a significantly weaker gravity well to lift it out of. There's no question that access to orbit on Mars could be achieved by a SSTO; Venus is a big "maybe" in this regard.D2O is worth about $300-400/kg. Given that D2O is only 20% deuterium by mass, pure D2 gas would probably be around $1,2k/kg; creating D2O from D2 is as simple as burning it. Of course with D2 gas there's the tankage mass issue. Other options that are deuterium-richer than D2O but easier to store than D2 include CD4 (40%), C2D6 (33%), C3D8(31%), ND3 (30%), C4D10(29%), BeD2(29%), etc.
Basically nobody has properly looked at this, but from basic biology, there is no reason to assume there would be any effect of deuterium depletion, and very limited effects of increases, which are only significant in vastly higher fractions.
Many, like Concert’s deuterated version of GHB, will work best only when partially deuterated in a specific way. But Graham Timmins, a medicinal chemist at the University of New Mexico who has been studying the field, reckons that when all is done and dusted, perhaps 5-10% of drugs on the market will be deuterated. The question is by whom?
Chemical isotope effects are particularly large for lighter elements in biological systems. The chlorella algae prefers deuterium over hydrogen, and tritium over deuterium. The enrichment factor depends on the conditions of growth; for deuterium to hydrogen an enrichment factor of 1.6 - 3 has been found, while for tritium to hydrogen the enrichment factor is about 2.5. Bacteria behave similarly, e.g. coli bacteria showing an enrichment factor for deuterium of 3.9.In as much as some of the hydrogen atoms are not exchanged readily due to the inertness of their chemical bonds, the isotopic fractionation which involves the easily exchangeable hydrogen atoms in these biological processes must have even larger enrichment factors for deuterium and tritium than their measured values would indicate
Quote Basically nobody has properly looked at this, but from basic biology, there is no reason to assume there would be any effect of deuterium depletion, and very limited effects of increases, which are only significant in vastly higher fractions.If that were true than why would anyone make deuterated drugs?
As for your comments dismissing peer-reviewed research... I don't have time to check every journal, but I pulled up the journal for one of them at random:http://www.ncbi.nlm.nih.gov/pubmed/23441611... and looked up its impact factor:http://www.tandfonline.com/toc/hnuc20/current2.322. Now, that's not spectacular, but it's not exactly fly-by-night either. Looking further:
Concerning the original depression study I posted:http://www.sciencedirect.com/science/article/pii/S0166432814004884... it's in Behavioral Brain Research. It has an impact factor of 3.028 (5-year=3.298) Again, hardly fly-by-night.One dismisses peer reviewed research at their own peril. Or, in this case, at the peril of their crew.
Quote from: Rei on 04/15/2016 11:15 amQuote Basically nobody has properly looked at this, but from basic biology, there is no reason to assume there would be any effect of deuterium depletion, and very limited effects of increases, which are only significant in vastly higher fractions.If that were true than why would anyone make deuterated drugs? Patentbusting
Something that low means it's essentially irrelevant....Still not impressive, and this is evident in the poorly controlled experiments they did
Quote from: Welsh Dragon on 04/15/2016 12:10 pmQuote from: Rei on 04/15/2016 11:15 amQuote Basically nobody has properly looked at this, but from basic biology, there is no reason to assume there would be any effect of deuterium depletion, and very limited effects of increases, which are only significant in vastly higher fractions.If that were true than why would anyone make deuterated drugs? PatentbustingSeriously, you're dismissing the entire concept, which there are tons of companies involved in and lots of papers being written about? So people are throwing their money at nothing and wasting their time researching nothing? Even just the filing costs on the patents alone - have you ever filed a patent? Just getting protection in a single country usually costs over $10k. Global rights can run into the hundreds of thousands. For a single patent.
QuoteSomething that low means it's essentially irrelevant....Still not impressive, and this is evident in the poorly controlled experiments they didOkay, what sort of journals are you publishing in? There's nothing at all wrong with a 3+ impact factor in neuroscience. And asserting that the peer review process must simply be wrong because you don't like the results is weak tea.
Which is small change compare to the billions you can make on drugs, so yes, patentbusting. Don't confuse scientific merit with commercial merit. Pharmaceutical companies priorities the latter.
I said nothing about peer review. I said their experimental setup was not good, not using the right controls.
I don't see how this discussion (or indeed topic) is relevant.
Are you seriously claiming peer review prevents crap from being published?
For other readers, this is a non-item. I don't know why the OP insists it's a problem, but it can be safely disregarded in the context discussed here. No properly done study has ever shown a problem with deuterium at Martian levels. I'm not here to prove a negative.
Poorly controlled experiments in secondary research journals touted by people selling over-priced miracle cures (literally one of the products is called "Miracle Light Water") is a major clue to be skeptical of these claims.