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June 3

Colchicine derivatives

I was reading the Colchicine article and came across this paragraph:

Because colchicine is so toxic, chemists are continuing to try to synthesize derivatives of the molecule that decrease the toxicity. The most important aspect of these derivatives is that they keep the tropolone ring (the ring with the methoxy group and the carbonyl) intact to retain the mechanistic properties of the molecule.

I googled around and found several Colchicine derivatives being studied like the paragraph says. [1][2][3][4]

Has any Colchicine derivatives been FDA approved yet? Daniel T Wolters (talk) 04:06, 3 June 2022 (UTC)

I did find a statement from 2018 that the novel colchicine derivative CR42-24 "is currently completing pre-clinical studies and is expected to be submitted for IND approval by FDA in a year".^[5] However, I did not find a follow-up. Four months ago CR42-24 was still being referred to as a "novel colchicine derivative".^[6]  --Lambiam 07:46, 3 June 2022 (UTC)

Thank you very much! I wish those scientists the best. Daniel T Wolters (talk) 20:09, 3 June 2022 (UTC)

Is the claim that relying on the pen causes forgetness, scientifically correct?

A few years ago, I've read books about memory techniques, and one of them (I don't remember) said that those who rely on their pen writing down, tend to forget things! But now I googled and found research that said that writing with a pen is much more effective for memory than typing on the keyboard. Is the claim that relying on what they write with their pen - causes forgetness, scientifically correct? --ThePupil (talk) 17:36, 3 June 2022 (UTC)

Was it writing with a pen vs typing on the keyboard only? Or, was it writing with a pen vs not writing at all? These seem to be two different scenarios. --Bumptump (talk) 19:32, 3 June 2022 (UTC)

I suspect that writing with a pen is better for recall. Writing with a pen is much faster than typing and you don't get distracted by correcting the inevitable typing errors. Well, that's true for older generation folk like me (aged 75) who were taught properly in primary school. Today's generation of kids don't even get told how to hold a pen properly and writing is not so easy for them and they can't spell. But they are more used to keyboarding, so maybe for them it is reversed and typing is better for recall. Dionne Court (talk) 03:09, 9 June 2022 (UTC)

What I saw (here, here, and here), was about handwriting Vs. typing.--ThePupil (talk) 02:20, 4 June 2022 (UTC)

What looks like poison ivy but has five leaves?

I didn't have any way to take a photo.

Like poison ivy, this plant had a leaf at the end, and two leaves on either side connected to the main stem. But then there were two more leaves connected to the main stem farther down the plant. I've seen this in my yard but not lately. I was in a park and there was poison ivy nearby.— Vchimpanzee • talk • contributions • 22:07, 3 June 2022 (UTC)

Poison sumac, maybe? --←Baseball Bugs ^{What's up, Doc?} carrots→ 01:00, 4 June 2022 (UTC)

Virginia Creeper is pretty common in the eastern United States. I see it both as ground cover and as climbing vines. -- Tom N talk/contrib 03:56, 4 June 2022 (UTC)

I'll second this. EvergreenFir (talk) 03:59, 4 June 2022 (UTC)

I described the leaves and I've known for a very long time what Virginia Creeper is. It also looks nothing like poison sumac.— Vchimpanzee • talk • contributions • 14:58, 4 June 2022 (UTC)

I think it is actually poison ivy, since the blog at poison-ivy.org records a rare observation of stalks with 5 leaflets. See The Mystery of 5-Leaf Poison Ivy.  Card Zero  (talk) 17:16, 4 June 2022 (UTC)

Until I can find a way to take a photo, that looks like it is correct, though the photo there is not what I saw,.— Vchimpanzee • talk • contributions • 18:39, 5 June 2022 (UTC)

June 4

UVPE?

I have a translucent white Nalgene-brand bottle that has a recycling symbol with 2 inside the triangle and "UVPE" below it instead of the expected "HDPE".

The product page is here,[7] and says it is made of HDPE.

Normally I would just dismiss this as a marketing neologism (UV resistant PE?) but seeing it as part of the official recycling symbol confuses me. Don't they have rules for that sort of thing or can the manufacturer just make new recycling symbols up?

I found our articles on Recycling symbol, Recycling codes (those two really should be merged into one article) and Resin identification code, but none of them mention UVPE.

I even searched for a MSDS, (Example:[8]) which was completely useless. Good to know that my water bottle isn't on the Chemical Weapons Convention List and that I should keep my water bottle "away from food and drink".

To confuse things further, [9] uses "UVPE" to describe Polyurethane instead of Polyethylene.

Does anyone know what the UV in UVPE means and whether there are any regulations concerning making up new recycling symbols? 2600:1700:D0A0:21B0:541C:3075:3AF9:5BBA (talk) 16:04, 4 June 2022 (UTC)

Googling UVPE yields various items, including [10], which says "The milky colored old style Nalgene bottles are UVPE which is HDPE treated to resist UV degradation." --←Baseball Bugs ^{What's up, Doc?} carrots→ 17:44, 4 June 2022 (UTC)

It should be noted that MSDS and SDS are often very product specific, as in specific to whatever purchase or lot they were ordered and shipped with. For many properties, this isn't of much consequence. Unless something like purity has changed significantly, the boiling point is likely to be the same across all SDS for a given compound or material. Some properties, however, will easily differ from SDS to SDS for the same product, and a big example of this is food safety. Your SDS sheet is from a supplier of UVPE, possibly one supplying it to the maker of the water bottle, but possibly not (and it doesn't really matter either way). It specifically notes that vapors may be released upon heating. This says to me that it isn't certified as food grade. Now, if prepared and treated properly, such as by heating to expel any remaining volatile organics that are dangerous, it may be possible to make the UVPE certifiable as food grade. So, the proper SDS to look at would be the SDS from the water bottle manufacturer, which will differ from the SDS from the UVPE supplier, as the bottle manufacturer should have done stuff to make it food grade. This is why I can use a plastic bucket that a bakery had received a shipment of flour to grow vegetables in a garden, but not a bucket made of the same material from a hardware store. The bucket for a shipment of flour was intentionally made to be food grade, while the hardware store bucket is not meant to be used with food, so they didn't go to the added expense of making it food grade. --OuroborosCobra (talk) 17:00, 8 June 2022 (UTC)

June 5

Why is it called lime?

None of the articles referring to limestone or Agricultural lime explain the term. I found a definition but don't know what to do with it. It seems like it should be mentioned on all those pages but that would be too much.— Vchimpanzee • talk • contributions • 18:38, 5 June 2022 (UTC)

It gets a mention in lime (material). First paragraph. Heh, and I see the short answer is "because it's slime", like when you're using it as cement.  Card Zero  (talk) 18:50, 5 June 2022 (UTC)

I guess that's enough for Wikipedia.— Vchimpanzee • talk • contributions • 21:15, 6 June 2022 (UTC)

I feel faintly irritated that the limestone article is useless to the visitor who wants to know "why is it called limestone". Does it have a citrus aroma? Is it sometimes bright green? Instead of easily finding out about the name, they will have to read about CaCO₃, 540 million years, dolomite and magnesium and karst and toothpaste, before finally getting to the little link to lime in the middle of the third paragraph, which is only likely to be noticed by people who already know the answer. I also dislike that it says "a chemical feedstock for the production of lime", which is probably technically correct, but seems to me to be needlessly opaque jargon. I want it to say something like "limestone is used for making lime", near the top. OK I made the change. I have a cynical feeling that somebody will be upset by change and will revert it.  Card Zero  (talk) 02:26, 7 June 2022 (UTC)

Further info,[11] and it may in fact be cognate with "slime". --←Baseball Bugs ^{What's up, Doc?} carrots→ 18:55, 5 June 2022 (UTC)

The entry in OED for lime has a note: "(In Old English any adhesive substance, e.g. glue, paste.)" See for example birdlime. But there is no specific mention in the etymology of a relation to slime as in the link above. A second note states: "another grade of the root occurs in loam n., lair n." The slime entry, however, states: "The stem is probably related to that of Latin līmus." Which google translate claims is the latin word for clay. An example usage from 1530 is "That slyme was a fatnesse that issued out of the earth, like vnto tarre; and thou mayst call it cement, if thou wilte." --mikeu ^talk 19:51, 5 June 2022 (UTC)

Improving the accuracy of certain Planck units

While reading through the above article it occurred to me that one should ostensibly be able to calculate the speed of light (exactly 299792458 m s^-1) by simply dividing out Planck length (1.61625518e-35 m) by Planck time (5.3912476e-44 s). In fact the absolute difference between the computed value of 299792422.815 m s^-1 and the current fixed value turns out to be -35.1849172711 m s^-1 so a respectable relative error of just -1.17364250942e-05%. Which isn't terribly bad obviously. But perhaps it would be possible to use something like the Von Klitzing constant or the fine structure constant to work our way backward (so to speak) to obtain even more precise values for these two Planck units? Earl of Arundel (talk) 20:10, 5 June 2022 (UTC)

First note that the "exact" character of the speed of light in SI units is an artifact of the definition of SI units. It isn't true, in practice, that we know the speed of light exactly. Because of the SI definitions, that uncertainty needs to be phrased in terms of our uncertainty as to how large a meter and/or a second is against our real-world artifacts. But this is a fact about SI; it's not a fact about the speed of light.

The Planck units are defined in terms of the speed of light c, Planck's constant h, and the gravitational constant G. The one we have the poorest estimate of is G, which per our article we know to about four significant figures. That is the limiting factor as to how well we know the Planck units relative to real-world artifacts, and you can't do better than that until you have a better estimate of G. --Trovatore (talk) 21:36, 5 June 2022 (UTC)

I do understand the inexact nature of measurement with respect to the speed of light itself, insofar as precise lengths and durations go. As you say, a much better approximation of G would help. But what are the chances of improving upon that? Earl of Arundel (talk) 00:33, 7 June 2022 (UTC)

Dimensional analysis shows that knowledge of the values of either the Von Klitzing constant or the fine structure constant, or for that matter of both, is not of any use here.  --Lambiam 19:13, 6 June 2022 (UTC)

Perhaps it could be approached like a maximization problem then? We have a fixed value for c, so for example just start from the current hypothesized value of Planck length then gradually adjust until its ratio with Plank time approaches the digits of c? Or vice versa. Either way, an error rate even better than ~0.00002% should be possible. No? Earl of Arundel (talk) 00:33, 7 June 2022 (UTC)

Just to illustrate, fix the Plank length at 1.61625518e-35 m then adjust the Planck time to 5.391246967e-44 s. That yeilds an error of less than 0.000000005%. Conversely, by adjusting the former to 1.61625537e-35 m and holding the latter instead fixed at 5.3912476 s, we achieve an error rate slightly below 0.00000002%. Maybe there is some intelligent way to explore the entire space of solutions? I don't know, but just fixing one of the two does at least bring their ratio a little bit closer to the speed of light. Earl of Arundel (talk) 00:48, 7 June 2022 (UTC)

No one has measured the number of Planck times in a second. We only know its magnitude in seconds by measuring G, taking the square root of the magnitude obtained, expressed in units N m²⋅kg^–2, and multiplying the result by 6.59912452×10⁻³⁹. Since the precision to which G is known is rather limited, so it is for the magnitude of t_P. It could be as little as 5.3911×10⁻⁴⁴ s or as much as 5.3913×10⁻⁴⁴ s. Since the ratio between t_P and ℓ_P is fixed by definition, it is pointless to attempt to tweak their ratio by tweaking one of the two, just as you cannot tweak the ratio between h and ħ by tweaking the value of h.  --Lambiam 05:52, 7 June 2022 (UTC)

June 6

Etiology of feline hepatic lipidosis

I’ve noticed that there is very little known about what causes feline diseases, in this particular case, feline hepatic lipidosis. What are the current trends, hypotheses, and theories about this disease in cats? Viriditas (talk) 02:15, 6 June 2022 (UTC)

respiration and oxygen

If plant respiration uses oxygen, why do plants release O2 into the atmosphere? Is it just that photosynthesis produces more oxygen than the plant can use? And do fungi also take oxygen from the atmosphere or soil gases? (I assume they do, since most are aerobic.) — kwami (talk) 04:03, 6 June 2022 (UTC)

Because in very simple terms, they use the energy from Photosynthesis, to split water, H₂O, and Carbon dioxide, CO₂, and recombine them to produce Carbohydrates and other organic compounds, H_nC_n+otherstuff, and Oxygen gas, O₂. The complex process may also use atmospheric O₂ (see Photorespiration and Cellular respiration), but overall more O₂ is created. The organics are what they build their physical material with, the surplus oxygen is a waste product. The Photosynthesis article says all this in its lede paragraph.

When Cyanobacteria first began using photosynthesis and similar processes (Green algae and their Plant descendents arrived a little later, see Evolutionary history of plants), resulting in the Great Oxidation Event, the extra oxygen they produced was toxic to almost all other living things on Earth and (it is thought) caused an Extinction event called the Oxygen catastrophe: eventually, Anaerobic organisms evolved the ability to tolerate increasing levels of oxygen, and then to use it. {The poster formerly known as 87.81.230.195} 90.199.171.123 (talk) 05:24, 6 June 2022 (UTC)

Yes, the lead says that, but poorly. Where it says that oxygen is also released as a waste product that stores three times more chemical energy than the carbohydrates, the obvious question is why the plant doesn't retain all that stored energy. So I take it that the O2 is surplus to need, with no good way for the individual plant to store it. (Or no need to store it, since enough is available in the atmosphere and soil.)

O2 will leave the plant very quickly. The O2 or the waste product is undoubtedly too difficult to store or to convert to energy on demand, unlike sugar. Abductive (reasoning) 07:00, 6 June 2022 (UTC)

And what of fungi? I assume that, having mitochondria, they share the basic cellular respiration of plants and animals. How do they get that oxygen? Is it passively absorbed from the environment, or is there something more active? And do they 'exhale' CO2 as a waste product? Do plants also exhale CO2, or do they manage to use what they produce?

Fungi respire. The issue in observing it is the low rate of metabolism in organisms that are not producing their own heat. The bubbles in beer are from yeast respiring. Plants must generate CO2 when they metabolize sugar, but they will grab it right back if they are photosynthesizing. Plants usually are CO2-limited, not energy-limited. Abductive (reasoning) 07:00, 6 June 2022 (UTC)

It's a bit difficult to work out which organisms do what from the main articles, because it's not clear if an article doesn't say because it's complicated or because it's simple. — kwami (talk) 05:43, 6 June 2022 (UTC)

Nearly all protists, plants, animals and fungi respire, and need oxygen to do so. The few exceptions prove the rule. Since plants produce their own oxygen, I'm told that they don't need oxygen from the air, but they do need oxygen. Abductive (reasoning) 07:00, 6 June 2022 (UTC)

Thanks. That helps. — kwami (talk) 07:25, 6 June 2022 (UTC)

Concerning oxygen is also released as a waste product that stores three times more chemical energy than the carbohydrates, I've just removed that statement from photosynthesis. See that article's talk page. IpseCustos (talk) 00:10, 8 June 2022 (UTC)

As for why the plant doesn't keep the waste oxygen which represents so much energy, oxygen is very reactive. And thus damaging to cells. Mitochondria exist to isolate the oxygen using reactions from the rest of the cell. --User:Khajidha (talk) (contributions) 14:19, 6 June 2022 (UTC)

To clarify a possible ambiguity, Khajidha, I think you mean "oxygen-using reactions"; correct? {The poster formerly known as 87.81.230.1965} 90.199.171.123 (talk) 07:34, 7 June 2022 (UTC)

Whoops. Yep. --User:Khajidha (talk) (contributions) 09:18, 7 June 2022 (UTC)

When making 1 kilogramme of carbohydrates, a plant produces about 1 kilogramme of oxygen, and when burning that kilogramme of carbohydrates, it consumes the same amount of oxygen. A plant only intends to burn a small fraction of the carbohydrates it makes. A large fraction is meant as structural material (wood consists of carbohydrates), which is not intended to burn. Best to get rid of the oxygen, or the wood might ignite to easily. Anyway, there's no way a one tonne tree can store one tonne of oxygen at standard pressure and temperature, as oxygen is a gas. PiusImpavidus (talk) 07:46, 7 June 2022 (UTC)

June 7

Is it known by what percentage does the vineyard yield increase if pruning it?

Is it known by what percentage does the vineyard yield increase if pruning it? I have heard it increases it, but I am not sure if it is a myth or supported by science. If it is scientifically approved, then what's the explanation behind it? --ThePupil (talk) 17:49, 7 June 2022 (UTC)

Hi, ThePupil. UC Davis have likely published data on that. Bottom line you're going to lose yield due to pest and disease if you don't spur prune at the start of the season, and likewise canopy management during the season is also important for those reasons and more. Grape vines are a lot like a plumbing system, if you got a double cordon with 6-8 spurs on each cordon then you're going to have an efficient transport of water and nutrients and a predictable (that's very important) yield. If you're letting a grape vine ramble you're creating ideal conditions (lack of airflow, less sunshine and more damp) for pests and disease (powdery, vine mealybug etc) and there won't be much of a basis for working out whether your yield is correct. Plus the rootstock might start to take over. Best to stay on top of it. You might find the 'umbrella canopy' system useful to protect from the increasing summer temperatures. Regards, Zindor (talk) 18:40, 7 June 2022 (UTC)

(Not the OP) Are you saying that it's not that the yield increases per se, it's that the yield per input (water, fertilizer, pesticide, etc.) gets better since the rambling bits are less efficient uses? 64.235.97.146 (talk) 19:47, 7 June 2022 (UTC)

In a rambling vine, because of the competition for nutrients and water, the fruit set would predictably be lower: there would be imbalanced cluster sizes and weights and in some clusters a lack of usable berries. With a trained vine you'll have a decent amount of inflorescences that set, a lack of useless bull shoots and suckers, and the resulting fruit quality will be high. Quality control for flavour is important in winemaking, so there needs to be the correct concentration of minerals, water, sugar and acids. Without even taking into account pest and disease, the actual yield (regarding area) will be higher. Additional costs are important too but the kind of problems not pruning would bring wouldn't be able to be solved with excessive fertiliser or pesticides. Regarding harvesting too, without a trellising system the machines will not be able to harvest the grapes, and with all the rambling vines even people hand-picking would find it abysmally difficult (grape vines attach themselves to each other with strong tendrils, making an impassable tangle). Hell, the snakes would be having a great time though! Zindor (talk) 21:06, 7 June 2022 (UTC)

Interesting - thank you! 64.235.97.146 (talk) 14:53, 9 June 2022 (UTC)

June 9

Determine a fluorescent lamp fixture's voltage requirement

I have a 6 W UV-C tube with a fluorescent lamp fixture. The seller says it's for 110 V. However, it failed to turn on after proper installation. The seller returned money to me and let me keep it. I now have a 220 V transformer. How do I know if it's safe to test if the fixture was actually a 220 V one? -- Toytoy (talk) 15:06, 9 June 2022 (UTC)