Wikipedia:Reference desk/Archives/Science/2017 October 2

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October 2

Earaches

Quoting Ear pain#Primary ear pain:

Ear pain can be caused by disease in the external, middle, or inner ear, but the three are indistinguishable in terms of the pain experienced.

Why? Are all the pain-sensing nerve endings located in one place, so they can't tell where the problem is? Nyttend (talk) 01:46, 2 October 2017 (UTC)

More likely the few nerve endings aren't distinguished in the brain. Many areas of the body have the nerves lumped together, when it didn't make much difference, in our evolutionary past, where the pain was. After all, what would you do differently depending on where in the ear the pain was, and how would knowing where in the ear the pain was improve your survival chances ? (There's a test where you place one or two tines on the arm, and try to tell which is which, and this shows we don't have the ability to distinguish which you might expect.) StuRat (talk) 01:52, 2 October 2017 (UTC)

References explain this differently. I'm reading (1) the inner ear has no pain fibres The structures of the inner ear (i.e., cochlea and semicircular canals) are innervated by cranial nerve VIII (vestibulo-cochlear), which has no pain fibers. Therefore, most pathologic processes of the inner ear do not produce pain.¸and (2) the nerves in the outer ear are shared with other remote sites on the body making it difficult to know where along these long nerves is the stimulus causing the sensation of pain. The sensory innervation of the ear is served by the auriculotemporal branch of the fifth cranial nerve (CN V), the first and second cervical nerves, the Jacobson branch of the glossopharyngeal nerve, the Arnold branch of the vagus nerve, and the Ramsey Hunt branch of the facial nerve. Neuroanatomically, the sensation of otalgia is thought to center in the spinal tract nucleus of CN V. Not surprisingly, fibers from CNs V, VII, IX, and X and cervical nerves 1, 2, and 3 have been found to enter this spinal tract nucleus caudally near the medulla. Hence, noxious stimulation of any branch of the aforementioned nerves may be interpreted as otalgia. 70.67.222.124 (talk) 20:20, 2 October 2017 (UTC)

I'll reluctantly agree with Stu. When they had to remove two thirds of my colon, I first went to a urologist, thinking it was a bladder issue. Pain and touch sensors are not very specific internally. My cousin had a ruptured appendix for over a week--normally fatal--but lived through the sepsis. μηδείς (talk) 14:38, 2 October 2017 (UTC)

It's probably worth while to link to the Cortical homunculus, though it doesn't seem to deal with internal organs. AndrewWTaylor (talk) 17:00, 2 October 2017 (UTC)

Applying coloured print to silicone?

A lot of programs I use have handy keyboard shortcuts but I use so many different programs that I just can't remember the majority of the shortcuts. My favourite solution would be one of those $2000 USD Optimus Maximum keyboards with an OLED display inside each key which changes depending on what program you're using. However, I'm a baller on a budget and the best I can afford is this $1 USD silicone keyboard cover which I was thinking I could put shortcut symbols onto and then swap with others when changing application. The problem I want help to solve is how to apply the symbols cheaply but in an aesthetically-pleasing way. The only way I can think of is to print them out on paper and cut them out and glue the little squares inside the cover but there's nothing aesthetically-pleasing about that. Are there other ways to cheaply apply coloured print to such silicone covers?

• Buy an alphabet stamp kit. Available at most craft stores. Abductive (reasoning) 03:39, 2 October 2017 (UTC)

• I'd just write on them with permanent marker, but then, I have neat printing. StuRat (talk) 05:07, 2 October 2017 (UTC)

"Permanent" ink wouldn't stick to silicone (at least not for long). ... Apparently, the only ink that sticks to silicone is silicone ink : [1] — 2606:A000:4C0C:E200:E19A:1892:B4DC:8315 (talk) 07:37, 2 October 2017 (UTC)

The ink will last a lot longer if you write it on the inside - especially if you can carve a small groove and fill it with ink (maybe with a sharp-pointed pen like a fineliner.) Smurrayinchester 07:49, 2 October 2017 (UTC)

For that you will not just need neat printing, but neat mirror printing! -- Q Chris (talk) 07:58, 2 October 2017 (UTC)

Laboratory-grade markers will work on a variety of surfaces where more common "permanent" markers rub off. The brand I'm familiar with is VWR [2], but you can find others. I've never tried them on silicone so I can't swear whether that will work, but it is what I would try (of course, I also happen to have VWR markers lying around). Dragons flight (talk) 08:32, 2 October 2017 (UTC)

I suspect they will work. This product Staedtler Lumocolor permanent special 319 specifically says it's for use on silicone [3]. It's available at various crafts or office supply stores so you probably don't even have to find someone who'd sell single quantities of labroratory equipment to random people [4] [5] [6] [7] [8]. It's even on Amazon [9] but the price there seems a bit out of wack. Nil Einne (talk) 13:28, 2 October 2017 (UTC)

Let us know if you try. VWR markers have some pretty amazing powers of penetration, but silicone seems pretty resistant. It is practically irresistible force vs. immovable object, or at least ought to be . But actually, I remember that VWR markers could still be resisted by plastic. I mean, you could take your RNase-free Northern blot (on nitrocellulose) and heat-seal it with a radioactive RNA probe in what I think was a polyethylene sleeve, and then, to make sure you keep track which probe is which, you could write on the outside of the polyethylene to permanently and prominently label the Northern blot inside the bag, without getting any counts at all on your marker or anything else. But the bag itself would only take the faintest trace of color from this operation. Wnt (talk) 00:57, 3 October 2017 (UTC)

And, I suspect that a punch-type stamp wouldn't 'take' (too "rubbery"). 2606:A000:4C0C:E200:E19A:1892:B4DC:8315 (talk) 07:46, 2 October 2017 (UTC)

• Print them on little squares of adhesive plastic, using a print process that resists abrasion. £20 label makers do this quite well. Andy Dingley (talk) 08:35, 2 October 2017 (UTC)

If alphabet or alphanumeric is all you need, I suspect you could find mirror image alphanumeric stickers. How well they'd stick to the silicone I'm not sure but it might be well enough that'll last if you're careful Nil Einne (talk) 13:31, 2 October 2017 (UTC)

Article on pubmed

In this paper on pubmed about decreased testosterone levels in biotin deficient rats it states "Biotin treatment of biotin-deficient rats reversed this condition". Could anyone with access to the full text tell me how long it took for the biotin treatment to reverse the decreased testosterone levels? Could you also tell me if there were any effects of biotin deficiency that were not reversed by the biotin treatment? Thank you for your time. — Preceding unsigned comment added by 125.164.134.97 (talk) 17:22, 2 October 2017 (UTC)

If you look up the URL on Sci-Hub, you have access to this paper. I call this an interlibrary loan from friends in Russia. Some will call this "piracy"; the same people called ResearchGate appropriate a few months ago, and now are ready to call them 'pirates' too unless they arrange a special censorship interface. [10] At each moment in time the life of a slave is a shameless theft from his master, so learn to be shameless.

Now as for the data, the rats were fed a biotin deficient diet for 7 weeks, then injected intraperitoneally with 20 micrograms of biotin for 6 days and killed one day after that. This treatment restored testosterone partially (13.63 +- 3.42 to 70.68 +- 9.35 vs. 103.37 +- 8.65 for controls. It rather mysteriously caused cholesterol to go up to 1.73 in biotin-deficient rats given biotin, vs. 1.35 to 1.39 for all other conditions - biotin deficient and control and testosterone-treated! A clue is that the biotin-deficient rats had 1335 for cholesterol in testis vs. 923 micromol/gram in control, but the value for the treated rats is not given. Presumably the excess store of cholesterol rapidly dribbles out??? They say an acetyl CoA carboxylase deficiency causes cholesterol to accumulate because acetyl CoA is shunted to a malonyl CoA pathway, but don't ask me to explain why it takes to the bloodstream once biotin is restored! 14C-leucine incorporation to proteins was fully restored from 32 to 40 pmoles/mg protein, same as controls. Bear in mind though that this is a small, limited study that cannot possibly show that all effects of biotin deficiency are reversible because they only looked at this much. Wnt (talk) 22:53, 2 October 2017 (UTC)

Get h without h20

Suppose I have no water. What is the easiest way to make hydrogen? I'm not looking for smartass answers like buy it on Amazon. Since hydrogen is in all carbohydrates, I figure that there must be some way I can mix common household goods to extract hydrogen. — Preceding unsigned comment added by 2600:1004:B145:B4FB:E9FF:D136:CD9A:87BE (talk) 22:43, 2 October 2017 (UTC)

Hydrogen-containing acid and metal produce a salt and hydrogen. This may not be the easiest way. Sagittarian Milky Way (talk) 23:03, 2 October 2017 (UTC)

Also see hydrogen production. Most current production is from fossil fuels. —PaleoNeonate – 23:41, 2 October 2017 (UTC)

Conceptually, any combustion reaction will convert compounds of C, H, and O into CO2 and H2O in proportion to the C and H present. This water, from any source, can then be used to make hydrogen as desired. (Ideally, I suppose the electricity comes from a generator run by the combustion reaction...) Wnt (talk) 00:51, 3 October 2017 (UTC)

Alternatively, cracking (chemistry) can convert many hydrocarbons into mixtures that contain hydrogen + smaller hydrocarbons. Wnt (talk) 00:49, 3 October 2017 (UTC)

The easiest way would be to drop iron filings into acid (this was how the French and others made hydrogen for balloons when there were no other methods of hydrogen production yet). 2601:646:8E01:7E0B:D403:68F1:A297:C74A (talk) 01:13, 3 October 2017 (UTC)

• Victorian aviation balloons were filled by reacting scrap iron, usually high surface area iron filings, with acid. Look at photographs for observation balloons of the US civil war, there are some good photos around.[11] The reaction was done in wooden barrels carried on wagons. These wagons had to have their iron fittings replaced with bronze or lead ones, owing to their corrosion from the acid fumes. Andy Dingley (talk) 11:59, 3 October 2017 (UTC)

Been too long (45 years) since chemistry. I was trying to do a feasibility test. Assume that I have iron filings and vinegar - two things that I could likely get easily just about anywhere. It seems to me that if I were to try to separate the hydrogen and then burn it to make water, I would be much better off distilling the vinegar to separate out the water. Perhaps I'm misreading the question and it isn't about trying to get hydrogen to make water. 209.149.113.5 (talk) 15:10, 3 October 2017 (UTC)

• All of the methods appear to use water in some form. The big industrial approaches react steam (water) with natural gas or coal. Methods using acid and metal have water in the acid. -Arch dude (talk) 15:43, 3 October 2017 (UTC)

• "Since hydrogen is in all carbohydrates, I figure that there must be some way I can mix common household goods to extract hydrogen."

Not necessarily. Consider the energy aspects. Andy Dingley (talk) 17:15, 3 October 2017 (UTC)

Thanks. I wasn't trying to make water. I was thinking about a scenario where you send an empty shuttle to a planet without water and it sits for many years extracting hydrogen that will be used as fuel once humans arrive. That made me wonder how it could work and everything I found when searching started with water.— Preceding unsigned comment added by 71.85.51.150 (talk) 01:29, 4 October 2017‎

Pyrolysis of natural gas can make hydrogen without water -- but for every 2 moles of hydrogen, you'll end up making 1 mole of useless and highly toxic carbon monoxide! 2601:646:8E01:7E0B:D403:68F1:A297:C74A (talk) 08:23, 4 October 2017 (UTC)

You may be interested in reading our Mars Direct article. From §First launch:

The first flight ... would take an unmanned Earth Return Vehicle to Mars after a 6-month cruise phase, with a supply of hydrogen, a chemical plant and a small nuclear reactor. Once there, a series of chemical reactions (the Sabatier reaction coupled with electrolysis) would be used to combine a small amount of hydrogen (8 tons) carried by the Earth Return Vehicle with the carbon dioxide of the Martian atmosphere to create up to 112 tonnes of methane and oxygen.

The NET 2024 crewed Mars mission mentioned by SpaceX's Elon Musk at last week's IAC ^{(video transcript)} plans to create methane and liquid oxygen via ISRU, utilizing atmospheric CO2 and ground ice. Prospecting for that ice, believed to be abundant in many locations (some close to the equator), would be done as part of the uncrewed mission two years earlier. Should local propellant production prove unworkable and a rescue mission becomes necessary, eight 150 t cargo flights would be needed to supply the 1100 t of propellant required for a 40 t payload capacity return trip. If only the ice (and thus hydrogen) portion of ISRU were lacking, a single delivery of LH2 would suffice.

For your hypothetical mission to a waterless planet, the reaction necessary to produce hydrogen will depend on the hydrogen bearing-resources you hypothesize being present. Bringing your own LH2 may be the best option. -- ToE 12:37, 4 October 2017 (UTC)