Wikipedia:Reference desk/Archives/Science/2020 December 24

= December 24 =

vaccine injection
I had what I think was an an MMR vaccine as a kid. Instead of a needle they used some kind of compressed air sprayer. Apparently a jet of vaccine droplets is shot into the person's arm at high enough speed that it goes through the skin without needing a needle. Therefore they were able to do a room full of kids in what seemed like just a few minutes.

1) what is that thing called, and 2) could they use it for covid vaccine, maybe after they get that vaccine a little bit more nailed down? Thanks. 2602:24A:DE47:BB20:50DE:F402:42A6:A17D (talk) 01:46, 24 December 2020 (UTC)


 * The thing is a jet injector. DuncanHill (talk) 01:55, 24 December 2020 (UTC)
 * Apparently it's being considered; hypodermic needles are cheaper but more prone to cause accidental injury and there are other pros and cons; see PREPARING FOR MASS VACCINATION (Oct. 2020). Alansplodge (talk) 15:54, 24 December 2020 (UTC)
 * Not to mention painful as a hypodermic needle can only make the incision as fast as a human can do it then stop at an acceptable geometry. Then the medicine is given at lower miles per hour and non-simultaneous with the piercing and retrieving the device irritates the wound significantly more than just taking the jet injector. In a jet injector the medicine is moving faster than the human throwing speed record probably and you aim before you pierce so it feels much better. As we want the first vaccination categories vaccinated first (even if they have a high "pain-per-neuron-cut ratio") and there won't be herd immunity till enough persons in later categories get immune this is an important consideration. Sagittarian Milky Way (talk) 17:40, 24 December 2020 (UTC)
 * I really don't think the physical speed of the movement of molecules in the vaccine into the injection site is the biggest factor in how rapidly vaccines can be delivered to a population. In fact, I highly doubt it is a factor at all. That's ignoring the fact that the issue right now in getting to herd immunity isn't the speed of delivery per dose, rather, it's actually having enough doses to deliver. --OuroborosCobra (talk) 18:20, 24 December 2020 (UTC)
 * It helps how much it hurts which can mildly affect how many high risk of coronadeath people die if there's no hypospray and some people on the high pain-per-neuron-cut end of the bell curve decide to just skip the injection and wait many months for herd immunity instead. I do note that I'm high pain sensitivity and intramuscular injections are too quick to hurt bad if they insert and retrieve at enough inches per second, and the actual injecting is bearable (your mileage may vary), this is why blood drawing especially some drawers is horrible as they have a tiny target. So if pain is a consideration make sure they don't rack up the inserting milliseconds like how the ones who do that probably would if they had to do their own shoulder or butt. Sagittarian Milky Way (talk) 18:48, 24 December 2020 (UTC)
 * Does the covid vaccine use a bigger needle (or anything like that) compared to other injections, blood draws, etc.? I've had several of those and they haven't ever hurt much in a purely physical way.  It's always been enough to just look in a different direction and think about something else while they stick the needle in.  Vaccines often have post-injection side effects for a day or so, that (if you experience them) will be way more annoying than the momentary needle prick of the injection itself, but are themselves no big deal except in some rare acute (allergic reaction) cases.  2601:648:8202:96B0:0:0:0:313A (talk) 01:59, 25 December 2020 (UTC)
 * Forgot about that, annoying day+ long vaccine ache. I really do not understand heroin addicts, if I had to inject myself without anesthetic that often I wouldn't live long before suicide. Sagittarian Milky Way (talk) 02:49, 25 December 2020 (UTC)
 * Note that the link I posted above doesn't mention anything about jet injectors being quicker, but does say that the patient doesn't have to be particularly compliant, which is a big advantage where children are concerned (wriggling while there's a needle in your arm is obviously problematic). Also that a smaller dose might be needed because the agent is delivered into the skin layer: "The dermis and epidermis of human skin are rich in antigen-presenting cells. As such, focusing the delivery of vaccines to these layers – rather than to muscle or subcutaneous tissue – should be more efficient, inducing protective immune responses with smaller amounts of vaccine antigen". However, that would require more research to determine. Alansplodge (talk)
 * If a smaller dose can be used that would be a big ameliorator for the manufacturing bottleneck and probably not make the site so sore. Sagittarian Milky Way (talk) 14:26, 25 December 2020 (UTC)

Plutonium tetroxide
My research indicates at least two reported observations of plutonium(VIII) oxide, though I am not 100% confident that these findings are definitive. The resources where I found such indicia were: –LaundryPizza03 ( d c̄ ) 02:06, 24 December 2020 (UTC)
 * Zaitsevskii et al. (2013). J. Chem. Phys. 139 (3): 034307. (citing an empirical study in 2011 that I could not access.)
 * Kiselev et al. (2014). Radiochimica Acta 102 (3).


 * Is there a question? --174.95.161.129 (talk) 07:39, 24 December 2020 (UTC)


 * Presumably the implied question is whether this warrants a mention in the section Plutonium, which only goes up to Pu(VII). The 2005 article "Experimental data points to the existence of plutonium(VIII) in alkaline solutions" sounds rather tentative, but the 2014 article "A spectrophotometric study of the reduction of Pu(VIII) and Pu(VII) in alkaline solutions" with the same first author (also the corresponding author of Kiselev et al. (2014), mentioned above) has a more definitive ring. The talk page of the Plutonium article may be a more appropriate place to signal this, but I think we'd like to see more independent confirmation. --Lambiam 09:14, 24 December 2020 (UTC)
 * Some past reports of Pu(VIII) were debunked by Shilov et al. in 2017, though some of the papers above are not mentioned in the cites. So I would use caution and not include it. That said, Shilov et al. allow that Pu(VIII) and Am(VIII) might be reachable through other means, so maybe one day we will get to have an update. Double sharp (talk) 09:22, 24 December 2020 (UTC)
 * Are any elements in the even longer 8th row predicted to be able to form neutral compounds above VIII in the brief moments before radioactive decay? Sagittarian Milky Way (talk) 17:12, 26 December 2020 (UTC)
 * See extended periodic table. Calculations predict it is likely possible for the early 6f elements (eka-actinides). Though that being said, we should also take everything with a grain of radioactive salt past maybe the very start of the 5g elements: they are tentative calculations. Double sharp (talk) 07:04, 5 February 2021 (UTC)

Your first article is a modelling study and predicts Pu(VIII) will be unstable. The article itself has been cited 17 times.

This article says, "In neutral chemical compounds, the highest known oxidation state of all elements in the Periodic Table is +VIII. While PuO4 is viewed as an exotic Pu(+VIII) complex, we have shown here that no stable electronic homologue of octavalent RuO4 and OsO4 exists for PuO4, even though Pu has the same number of eight valence electrons as Ru and Os."

This article says, "Metal tetraoxygen molecules (MO4, M = Fe, Ru, Os, Hs, Sm, Pu) of all metal atoms M with eight valence electrons are theoretically studied using density functional and correlated wave function approaches. The heavier d-block elements Ru, Os, Hs are confirmed to form stable tetraoxides of Td symmetry in 1A1 electronic states with empty metal d0 valence shell and closed-shell O2– ligands, while the 3d-, 4f-, and 5f-elements Fe, Sm, and Pu prefer partial occupation of their valence shells and peroxide or superoxide ligands at lower symmetry structures with various spin couplings."

Your second article has been cited six times. It says, "The existence of Pu(VIII) was shown in alkaline solutions and in nonpolar solvents (CCl4 and CHCl3) on the ground of such experimental facts like extraction of plutonium species, obtained by means of ozonization of Pu(VI) alkaline solutions into CCl4 and CHCl3; volatility of Pu compounds out of aqueous alkaline solutions, and the mentioned solvents."

This article suggests the existence of Pu(VIII) in alkaline media, and has been cited 32 times.

It would certainly be worth mentioning something about all of this, with citations, for at least the following reasons. 1: Since Pu's lighter d-block chum, Os, can reach VIII, it's interesting to speculate if Pu could follow suit; 2: Such references provide a great starting point for students or researchers; 3: As a reader, those are the same sources you might want to find, or look up again, in future.

At the least you could say something like, "Claims for Pu(VIII) have been reported [ref 1, ref 2 etc] but remain unconfirmed in light of the expected instability of this state. [ref 3, ref 4 etc]." From my limited reading of the sources it looks like Pu(VIII) in aqueous solution is expected to be more achievable than e.g. PuO4. --- Sandbh (talk) 00:33, 27 December 2020 (UTC)

How to plot magnetic field lines around a metal?
Imagine I want to simulate the magnetic field lines of a magnet when there is a metal nearby, how could I do this? I've searched, but all I find is the usual dipole plot. For reference: https://www.kjmagnetics.com/blog.asp?p=shielding-materials, https://www.kjmagnetics.com/magneticfield.asp https://www.kjmagnetics.com/blog.asp?p=block-or-extend If you know a software that's awesome, but if you also can derive a formula to simulate it, that's great too. I'd like to plot https://physics.stackexchange.com/questions/464272/magnetic-field-gradient-of-a-ring-magnet Thanks Sistemx (talk) 20:26, 24 December 2020 (UTC)
 * You could ask K&J Magnetics, Inc. about the particular FEA (Finite Element Analysis) software they mention at your second link. Wikipedia offers a List of finite element software packages. I can't give any specific recommendation but here is a review of 7 popular programs. 84.209.119.241 (talk) 23:09, 24 December 2020 (UTC)