Wikipedia:Reference desk/Archives/Science/2019 August 30

= August 30 =

Cant wear silver
I have met several people and have observed for myself that they are not able to wear silver. A close friend of mine is not able to wear gold or silver, but only white gold or platinum. If he wears silver is will tarnish to black within 24 hours or less, leaving a black mark on say a finger where the ring was. If earrings are left in they will start to fester just as quickly. Gold for my friend is worse and if worn as a ring can cause blisters and if in earrings can cause festering within hours. Is this a known side effect and why does this happen to him? Is this common? Can something be done to prevent this? Why does this not happen with white gold? His Aunt has the same affliction. If she tries on a piece of jewellery just for a moment, the gold necklace, when observed the next day will be tarnished and black, even though she only wore it for a minute or two. Thanks Anton 81.131.40.58 (talk) 07:31, 30 August 2019 (UTC)


 * It is possible to be allergic to a metal, an example of allergic contact dermatitis (mechanistically, the allergenic epitope is typically some dissolved metal ion bound to a protein). Since jewelry is usually some type of metal alloy, someone who reacts to wearing it would need to visit a doctor to find out precisely what they are reacting to. That is, a "gold" necklace could well contain copper, nickel, silver, or other metals. White golds are a different group of alloys as compared to yellow golds, and are also typically plated with another metal, so it's not surprising there would be a difference. "White gold" is also sometimes a reference to platinum. The blackening of silver is a result of sulfur tarnishing, and the sulfur content of skin/sweat can vary considerably from person to person, as well as in one person over time or with different diets. If someone is unable to wear jewelry but wants to, they should really visit a doctor to find out what's happening. If a person knows they are allergic to a certain metal, but they still want to wear it, they can talk to a jeweler - there are coatings that can be applied to metal jewelry to prevent the skin from coming into contact with the metal. Someguy1221 (talk) 07:58, 30 August 2019 (UTC)
 * This is pretty common, regularly addressed in women's/health magazines/blogs. A "jewelry itching" search returns tons of results. My sister as the same kind of concern, and she just adopted jewelry she can wear, instead of stubbornly trying to wear jewelry badly interacting with her skin. AFAIAC, this seems to me the best move. Plus, it just happened that she cannot bear jewelry that would be her second choice (silver, low grade gold), while her favorite (at least 18/24 gold, 900/1000 even better) is OK. Coincidence? Probably not. The aptitude to be turned into jewelry enjoyable for most people (not itching, not staining the skin, soft,...) certainly makes part of the ancestral value of gold. Gem fr (talk) 12:55, 30 August 2019 (UTC)


 * Tarnish is almost all due to sulfides, which are easily released through the skin. A diet rich in garlic, onions, eggs or especially any bodybuilder's powdered protein drink (they're based on dried eggs) will do this.
 * Intolerance is usually due to some nickel or nickel plating, rather than the piece being pure silver. This is why the EU have banned nickel for skin-worn jewellery. Andy Dingley (talk) 13:13, 30 August 2019 (UTC)
 * A friend, a smoker, once borrowed a lathe and managed to etch fingerprints in the chrome plate of one of the handwheels. Andy Dingley (talk) 14:16, 30 August 2019 (UTC)
 * Not important, but the most widely used protein supplement is whey protein, which is, well, whey. Any complete protein source will contain the sulfur-containing amino acids, methionine and cysteine. --47.146.63.87 (talk) 20:32, 1 September 2019 (UTC)
 * Would thick electroplating the gold with pure good solve this? You could get it recoated if it wears through. Why doesn't yellow jewelry gold tarnish if it's almost half silver and copper? Sagittarian Milky Way (talk) 13:41, 30 August 2019 (UTC)
 * It's remarkably difficult to predict the degree to which alloys will resist tarnish. There is a significant amount of prosthetic dentistry literature measuring this resistance for a huge variety of alloys. Someguy1221 (talk) 08:22, 31 August 2019 (UTC)
 * There could also be simple mechanical issues, regardless of the material. Jewelry that rubs against skin could cause irritation; while large, tight items of jewelry, like thick bracelets, could have an effect similar to a cast, by keeping oxygen away from skin and preventing sweat from evaporating. SinisterLefty (talk) 14:23, 30 August 2019 (UTC)

The most common cause of tarnishing of jewellery is cosmetics on the skin. Tarnishing can also be caused by prescription medications in the wearer's bloodstream. . Richerman (talk) 19:52, 31 August 2019 (UTC)

Could sex offenders be fixed with brain surgery?
Is it a reasonable idea to treat sex offenders by ablating the parts of the brain responsible for sexual motivation/impulses? I think this could be cheaper than incarceration in some countries (probably not the US). — Preceding unsigned comment added by 88.106.182.98 (talk) 15:00, 30 August 2019 (UTC)
 * You are assuming that sex offenders act on sexual motivation. 135.84.167.41 (talk) 15:01, 30 August 2019 (UTC)


 * Just FYI most motivation for sexual offences has a power motivation rather than a sexual motivation. Raping someone is not about having sex with them but rather having power over them.  Thanks Anton 81.131.40.58 (talk) 16:39, 30 August 2019 (UTC)
 * The technology does not yet exists, and therefore the OP actualy is asking us to predict the future . We don't do that here. --Lgriot (talk) 17:03, 30 August 2019 (UTC)
 * The OP's premise is flawed on several levels. ←Baseball Bugs What's up, Doc? carrots→ 18:41, 30 August 2019 (UTC)


 * It's an oversimplifiction to say most sex crimes only have a single motive, just as it would be to say that most murders have the same motive. SinisterLefty (talk) 13:54, 31 August 2019 (UTC)
 * Well said. Our article: Causes of sexual violence. -- 173.72.209.196 (talk) 20:44, 31 August 2019 (UTC)


 * This is an issue that will come up in the future. There was a time when a lobotomy was often performed when somebody exhibited "unacceptable behavior", with the goal of "fixing" them. It didn't work very well, as in the case of Rosemary Kennedy. But eventually, presumably, we will be able to modify whatever part of the brain we find objectionable, but this brings up all sorts of moral questions, such as whether we are "curing" something that doesn't need to be cured. For example, many have tried to "cure" homosexuality, "miscegenation", and even left-handedness. Now we would see it as unacceptable to perform brain surgery to "correct" such "conditions". Even conditions we still consider to be mental disorders, like bipolar disorder, have some benefits, as many such people achieve amazing things during their manic phases. And if such surgery was done without the consent of the patient, then there's the additional possibility of it being used punitively rather than therapeutically, as in the case of sterilizations done under NAZI Germany, and the law being applied unfairly, with poor people falling victim far more often than the rich. Also, could we be certain that such a law wouldn't be applied to the wrong cases, like a guy just over 18 having sex with his g/f just under 18 ? With "zero tolerance" laws, which really means "zero judgement", this scenario is possible. SinisterLefty (talk) 18:45, 30 August 2019 (UTC)


 * This smacks of eugenics. ←Baseball Bugs What's up, Doc? carrots→ 18:47, 30 August 2019 (UTC)


 * This is why at least some states have close age exceptions. Sagittarian Milky Way (talk) 18:57, 30 August 2019 (UTC)
 * Being as how sex offenders' core problem is a desire to control others, the first subjects submitted for this kind of treatment should be the ones who propose it! ←Baseball Bugs What's up, Doc? carrots→ 21:01, 30 August 2019 (UTC)
 * As with lobotomy itself, this sort of thing is reminiscent of the politician's syllogism. Someguy1221 (talk) 08:24, 31 August 2019 (UTC)
 * Politicians would be next on the list of experimental subjects. ←Baseball Bugs What's up, Doc? carrots→ 14:02, 31 August 2019 (UTC)
 * Please refer to the page header: "We don't answer requests for opinions, predictions, or debate." At present, medical science does not recognize any neurosurgical procedure as useful in treating mental or behavioral disorders with a sexual aspect. Note that "sex offender" is a legal classification; not all persons classified as such have a recognized medical disorder. We cannot predict what treatments may exist in the future. It is worth noting that the human neurobiology of sex and sexuality is complex; there is not a single "sex center" of the brain. If you want to learn more about this topic, we have some relevant articles; you may also wish to consult textbooks, lectures, and the like. --47.146.63.87 (talk) 21:00, 31 August 2019 (UTC)
 * The OP won't likely be back, so I'm boxing this one up. ←Baseball Bugs What's up, Doc? carrots→ 01:12, 1 September 2019 (UTC)

Chemical castration is also relevent, as many of the same moral and legal issues come up. SinisterLefty (talk) 03:01, 1 September 2019 (UTC)


 * Since the brain is who we are, it's possible in principle as changing the brain means changing the person to become someone else. Count Iblis (talk) 08:41, 1 September 2019 (UTC)


 * Exactly. At some point you're just executing the offender and creating a new person and placing that person in the body of the executed perp. SinisterLefty (talk) 00:45, 3 September 2019 (UTC)
 * We enter the rich and complex territory of identity, choke-full of Sorites paradoxes and non locality (that is, your identity is not just who you physically are, but also include who people think you are) Gem fr (talk) 01:00, 3 September 2019 (UTC)


 * You mean chock-full ? SinisterLefty (talk) 03:28, 4 September 2019 (UTC)
 * would also be ok, but I did meant choke-full https://en.wiktionary.org/wiki/choke-full#English Gem fr (talk) 11:59, 4 September 2019 (UTC)
 * Personal identity changes gradually as your brain changes, you are not the same person that came out of your mother's womb. In principle, you only exist at the present moment, if you are reading this part of this sentence you are not the same person as the one who is now reading this part. See also here. Count Iblis (talk) 09:35, 4 September 2019 (UTC)
 * As I said: sorites paradox Gem fr (talk) 11:59, 4 September 2019 (UTC)