Wikipedia:Reference desk/Archives/Science/2014 July 13

= July 13 =

"Nutritional" Insulin Antagonists?
Did someone here herad of any Insulin-Antagonistical foods (Or effective Supplements for that matter) documented in some "serious" Scientific literature? Thanks. Ben-Natan (talk) 01:27, 13 July 2014 (UTC)


 * Were you really concerned people reading this would need to know what food is? -- Jayron  32  04:04, 13 July 2014 (UTC)


 * Pardon? Ben-Natan (talk) 04:39, 13 July 2014 (UTC)


 * Of all the words you thought people would need to read a Wikipedia article about because they wouldn't understand it, why would "food" be the one you choose to direct them too? -- Jayron  32  04:56, 13 July 2014 (UTC)


 * To clarify, are you asking about foods that destroy insulin in the blood, or that prevent the release of insulin into the blood ? StuRat (talk) 05:03, 13 July 2014 (UTC)
 * I'm asking what foods can interfere with the Biosynthesis of Insulin (another good question will be what are it's precursors - One can avoid them to achieve this goal too). Ben-Natan (talk) 11:47, 13 July 2014 (UTC)


 * Insulin is a protein, and as such its precursors are basically the same as those of all proteins, namely, the level of protein in the diet. Because it is a large molecule, substances that act as agonists or antagonists to it are rare.  A few have been synthesized in the laboratory, but as far as I can tell none have been found that occur naturally. Looie496 (talk) 16:06, 13 July 2014 (UTC)


 * Precursors of proteins include amino acids. StuRat (talk) 19:43, 13 July 2014 (UTC)
 * Sure they include them - But isn't there any specific A.Acid (Or A.Acids) we can associate with Insulin? Thanks. Ben-Natan (talk) 22:18, 13 July 2014 (UTC)


 * You can look up the amino acid sequence, but any such effect would be very subtle and hard to exploit. As our Insulin article explains, there are lots of factors that influence insulin release, and I'm sure you'll get a lot more mileage working with them.  I can't see any sign of a usable way of altering insulin synthesis. Looie496 (talk) 01:04, 14 July 2014 (UTC)


 * As far as proteins go, insulin is quite tiny. In fact the monomer is a little under 6kDa in molecular weight, which means even the hexamer (the inactive/storage form) is a mere 36kDa which is still small-to-medium in size for a globular protein. Small side point, the active form of the monomer is actually a heterodimer formed from cleavage of a single precursor. Another confounding variable here is that insulin is sometimes referred to as a "peptide hormone" which is misleading, as it has a very well defined tertiary structure. To make a true insulin antagonist you'd need something with the same structure and surface properties as insulin, but incapable of eliciting a pharmacological response. I don't think it would be that difficult to do recombinantly, in fact given the huge number of synthetic insulin analogs already in existence it's likely someone already has. Although these certainly wouldn't be considered GRAS, so it's doubtful you'd ever encounter them in food. (+)H3N-Protein\Chemist-CO2(-) 14:44, 14 July 2014 (UTC)

Solar roadways
is this for real or just some well-connected people bilking the public out of its money? can they keep the money? and how to pull off something like this oneself (I really, really hate my current job)? I mean, they did their homework, by securing a grant from DOT and getting a has-been scifi actor plug them to his 8M Twitter followers Asmrulz (talk) 09:33, 13 July 2014 (UTC)


 * Any citeable info, especially third-party analysis such as you seek, might be suitable to add to the Solar Roadways article. But see also its talkpage, where there are strong opinions about various such analyses and other material in that article (you might find useful commentary to answer your question, but you also might find it doesn't meet wikipedia's standard to include). DMacks (talk) 09:49, 13 July 2014 (UTC)


 * We recently had this Q here (see Reference_desk/Archives/Science/2014_May_24 and the earlier Reference_desk/Archives/Science/2011_December_23). I believe the consensus was that, while it might be useful in areas where you want to put signals in the road at night using built-in LEDs, especially if that area is off the grid, actually using solar roadways to produce electricity for the grid is absurd.  The cost would be far higher than current methods, and also solar roadways would need to be kept clean to work well.  And even using them for LED in-road signals is much more expensive than signs that reflect headlights, but some might be willing to pay the higher price, since signs represent a danger, should a car run into them.  Signs are also more likely to become dangerous projectiles in a hurricane or tornado. StuRat (talk) 15:00, 13 July 2014 (UTC)


 * The project has many *many* problems. It's fairly clear that it doesn't make logical/scientific/economic sense.  However, a $100,000 DOT grant isn't really very much - they give small businesses grants to develop all sorts of "out there" ideas in the hope that one day one of them will make it big.  The idea of using them for in-road LED signals doesn't work because the density of LED's required to do that would make the panels unaffordable.  Having to heat them to remove snow and ice in order to get enough solar power to heat them...is kinda circular - and besides, if there was enough sunlight hitting the surface to generate that much heat, it would already have melted the snow and ice!  The concept is totally full of holes.   BUT with crowdfunding, you don't have to have an idea that actually works - only one that enough people THINK will work...and for that, this works just fine.


 * Can you pull something like this off yourself? Maybe. Can you think of something sufficiently plausible - can you make a reasonable prototype - do you have the interpersonal skills to convince other people that your idea is good - and are your moral standards low enough that you don't give a damn that it obviously won't work?   There are plenty of people like that - they'll happily sell you a magnetic bracelet to cure your arthritis or a set of pads you stick onto the soles of your feet to 'draw out toxins'....claim to have a car that runs on water (that's always a popular one!).  Hardly any of them go to jail for doing it.


 * Alternatively, you can try to do something useful and meaningful with your life. SteveBaker (talk) 20:09, 15 July 2014 (UTC)


 * As for the LEDs not working when the road is covered with snow, note that the alternative, reflective signs, often doesn't work either, when the signs are covered with snow. And during a blizzard, you aren't likely to be able to see either, in any case. Then there's information painted on the road itself, such as indicating a left turn lane.  I hate those.  No only are they unreadable when covered by snow, but also when the car in front is idling on top of one.  And then the paint inevitable starts to wear off.  (Lane markers are OK, as cars rarely drive on those, but painting within the lane where it will be run over by every set of passing wheels is impractical.) StuRat (talk) 23:30, 16 July 2014 (UTC)

Can you identify this yellow moth, seen in Yorkshire, UK, Yesterday
It looked very like a yellow leaf, which seems odd for this time of year. It must be unusual in the UK as I have not seen one before. -- Q Chris (talk) 15:27, 13 July 2014 (UTC)


 * Yes, that's a Brimstone moth (Opisthograptis luteolata). Handsome chap. Richard Avery (talk) 15:31, 13 July 2014 (UTC)


 * Our brimstone moth article says that sometimes they have 3 broods per 2 year period, resulting in adults at odd times of the year, where their presumably fall camo doesn't work well. I wonder why this happens, though, as they would seem to be "sitting ducks" for predators, as a result.  If they also aren't native to the UK, I wonder how that one got there or if they are an introduced species.  StuRat (talk) 15:37, 13 July 2014 (UTC)


 * Its range is across the Palearctic which includes the British Isles. It is actually widespread in the UK . Richerman    (talk) 18:56, 13 July 2014 (UTC)


 * I'd looked at the Brimstone moth article, but the shape of the one in my picture is much more of a delta than that in the article. I suppose it could just be holding its wings in a different position. -- Q Chris (talk) 15:40, 13 July 2014 (UTC)


 * The delta shape is more apparent in the photo here, which is very like yours. It shows the distinctive reddish markings near the "leading edge" of the wing, and the less obvious greyish "dots" across the wings. AndrewWTaylor (talk) 18:43, 13 July 2014 (UTC)

Hiv transmission
How is HIV transmitted in those very few cases where people claimed to have caught it despite having protected sex? The only thing I can think of is that the condom broke or failed in some way so that fluid leaked from it. Are there any other ways? — Preceding unsigned comment added by 90.192.101.145 (talk) 17:20, 13 July 2014 (UTC)


 * The [] and [] pages have all about it. OsmanRF34 (talk) 19:30, 13 July 2014 (UTC)


 * (ec) It seems that the mouth can transmit HIV, although not from saliva, but from blood, due to small injuries. (You might get blood when using dental floss, for example.)  See  (same as 2nd source above.) StuRat (talk) 19:32, 13 July 2014 (UTC)


 * The bulk of HIV as well as hepatitis C transmission goes through shared needles by drug abusers. --AboutFace 22 (talk) 23:45, 14 July 2014 (UTC)


 * Actually, our article indicates that the bulk of HIV transmission is through sexual contact. While direct blood-to-blood contact (as with shared needles) is a much more effective route to infection on a per-incident basis, there are a lot more people having sex than sharing dirty needles. TenOfAllTrades(talk) 12:34, 15 July 2014 (UTC)
 * In addition, while our article on hepatitis C doesn't seem to have an overall picture of transmission, the info it does have suggests the bulk of hepatitis C is not via intravenous drug users sharing needles. In particular, it notes that in developing countries, blood transfusion and unsafe medical practices generally represent the bulk of transmissions. Since it's likely a big percentage of transmissions are in the developing world (both because of their higher population and their more limited control over transmission), probably enough that regardless of how the higher rate of IDU in developed countries compares with the lower rate in developing ones, it' likely most transmissions are not IDU. For example Egypt evidentally has the highest rate of infection in the world and the majority of their cases comes from such health care transmission. And our article notes, with a 2007 source that some countries don't screen blood transfusions for HCV. While the rates among IDU users are very higher in many countries (as noted by our article), somewhat similar to the sexual intercourse-HIV case, there is often a lot more people receiving medical treatments. (Hepatitis C doesn't appear to significantly spread by sexual intercourse, so it's not a major risk factor.) Nil Einne (talk) 13:45, 15 July 2014 (UTC)