Wikipedia:Reference desk/Archives/Science/2016 November 28

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November 28

video

What's happening in this video[1]? Is it for pipeline construction or something? ECS LIVA Z (talk) 04:28, 28 November 2016 (UTC)

It looks like an enormous mine-clearing line charge test; but without more context, it's hard to be certain. Do you have any further information, like where you found the video? Nimur (talk) 04:44, 28 November 2016 (UTC)

It was just randomly on the internet without any context. ECS LIVA Z (talk) 04:52, 28 November 2016 (UTC)

It appears to be an extract from Dykon Blasting Corporation's promotional video for the ISEE Conference a few years ago. Here is their 2016 video; there is an archive of older videos on their website. This company sells explosives services for construction and military purposes. Nimur (talk) 04:58, 28 November 2016 (UTC)

Here is the entry form for next year (2017): Give us Your Best Shot: 24th Annual Photo Contest. Be aware that the contest is intended for explosives professionals who have appropriate permissions, exercise proper procedures, and exhaustively enforce safety controls; it's not intended for home-brew bomb-makers. Don't play with explosives. Nimur (talk) 05:04, 28 November 2016 (UTC)

These seem like the kind of people who consider *only* triple checking something to be dangerous.Naraht (talk) 16:06, 28 November 2016 (UTC)

Thank a lot!

What are these blasted trenches used for? In the video I see some pipelines, so pipelining is probably one of the uses. Anything else? Would a road/railway need blasted trenches like these? ECS LIVA Z (talk) 00:21, 29 November 2016 (UTC)

Possibly, if the road has to e.g. cut across a ridgeline. 2601:646:8E01:7E0B:4C25:8F4F:2BC7:C702 (talk) 01:17, 29 November 2016 (UTC)

Removing red-28 dye from a carpet - and Red-28 in children's toothpaste.

So over Thanksgiving, two of our grandkids decided to have a "tea party" in their bedroom...which had a new carpet laid just a couple of weeks before.

They started out playing with cups of water - but then decided they needed "food"...and (by some peculiar twist of a 5 year-old's brain) they decided to use toothpaste - a Crest childrens paste in watermelon flavor.

Inevitably, this got dropped onto the new carpet - and in their efforts to clean it up before any parent/grandparent could find out - got it rubbed deeply into the pile over a large area.

OK - so we wash it, we try every carpet spot-remover we have, we Google "getting pink stain out of carpet" and try things like hydrogen peroxide and heat from an electric iron.

No luck whatever...which is weird because these techniques seem to work well for EVERYONE else.

In desperation, I look on the ingredients list - and discover that the toothpaste's coloring is "RED 28". This is not listed in Food dyes - and only after much cunning Googling do I discover that this particular chemical is banned for foodstuffs in the USA! It's allowed only for certain cosmetics - and for "drugs".

This paper: https://ntp.niehs.nih.gov/ntp/htdocs/chem_background/exsumpdf/reddyes_508.pdf seems to suggest that the stuff is pretty nasty - but my knowledge of the chemistry and the vocabulary of these kinds of reports is sadly lacking, so maybe I'm misunderstanding it.

Anyway: Two questions:

1. How do you get RED-28 out of a carpet?
2. How the heck can they put a not-allowed-in-foods chemical into toothpaste that's recommended for "2 years and up" kids - who are pretty much certain to swallow the stuff? Can they really classify toothpaste as "A Drug"? Also why would they do this? There are plenty of other red colorants they could have used instead.

TIA SteveBaker (talk) 19:01, 28 November 2016 (UTC)

1. How to clean the carpet. The linked report seems to imply that D&C Red No. 27 (insoluble) changes to D&C Red No. 28 in a high-pH environment. I would therefore try flushing with dilute sodium hydroxide (caustic soda). Wear rubber gloves, protect eyes and rinse thoroughly with water.
2. How could a potentially phototoxic colorant be allowed in toothpaste? According to the linked report, D&C Red Nos. 27 and 28 were approved as additives for some drugs and cosmetics in 1982. A toothpaste manufacturer's lawyers might see that as adequate and even argue that toothpaste is not intended to contact the eye nor be exposed long to light. Crest (toothpaste), possibly like this, is made by Procter & Gamble and there is consumer support at https://pgconsumersupport.secure.force.com/ContactUs/emailus?brand=Crest&country=United+States+of+America&language=English-US Blooteuth (talk) 20:51, 28 November 2016 (UTC)

Thanks...

1. I'm concerned that over-aggressive treatment might bleach out the other dyes in the (oatmeal-colored) carpet. So how dilute is "dilute" in this case?
2. The product you linked to seems to be green, and to use two food-legal colorings...it's from Colgate. The one we're concerned about is "Crest Stages Pro-health kids": LIKE THIS. I already contacted them twice - but so far, no response. SteveBaker (talk) 21:42, 28 November 2016 (UTC)

Obviously, you should test a series of bleach dilutions on a portion of the carpet that will be covered by a couch. Or test on a large region of the carpet, if you dislike it to begin with. Or just bleach the whole damn thing, to keep it even :) Someguy1221 (talk) 22:44, 28 November 2016 (UTC)

Lye will damage the rug and there are better alternatives, if you wanted high pH or alkalinity (such as washing soda). Page 5 does say No 28 is more soluble, but also says "The transition from D&C Red No. 27 to D&C Red No. 28 occurs between pH 3.4 and pH 5.0 (CRC, 1986)." So it appears you want an acid. So something like a mixture of baking soda (a little bit to raise the pH), lemon juice (pH 2) and water would be better. Since the dye was a toothpaste ingredient you might also try scrubbing with the brand's white toothpaste version in the hope that the dye is soluble in that. The iron may have set the dye into the fibers, so you may have to resort to experimenting with diluted chlorine bleach (perhaps testing solutions on a rag with the pink toothpaste rubbed into it). Four or five parts water to one part laundry bleach should suffice. Ideally the dye will vanish within 20 seconds or less (longer times would indicate it's ineffective and further risks fading and/or damaging the fibers). Ventilate the room and keep pets away before you begin: opening windows and using fans to direct any fumes away is recommended. Having put on gloves first, sponge the carpet with the bleach and then blot it with paper towels to remove the excess bleach as fast as you can and immediately flood with hydrogen peroxide. The peroxide will react with the remaining bleach and immediately stops further unwanted action on the rug. Apply only to small areas because noxious gases (chlorimides) can form from any nitrogenous compounds that happen to be in the rug. With a new rug this should not be a problem, but an old rug can accumulate these. --Modocc (talk) 22:52, 28 November 2016 (UTC)

I don't know. If I understand this correctly, the whole damn thing is an aromatic system (9 double bonds = 18 electrons, following Huckel's rule. Every position is oxygenated or halogenated. I don't know what bleach is going to do to that, though I'm not good enough at organic chemistry to be sure. If it works, great... The photoactivation might mean that room light has bound some of it to the carpet - I don't know that for sure either. Would some sort of nucleophile/reducing agent break apart ether linkages? No idea, I'm talking out my ass. If I had some beta-mercaptoethanol handy I'd be sorely tempted to dilute it way out and see what happened, but that would only get me in a lot more trouble... Wnt (talk) 01:16, 29 November 2016 (UTC)

I suppose the real answer here is "contact the manufacturer". They might have a clue, and if not, well, it would be nice if they couldn't play a "well, we would have just said..." game should you ever end up suing their asses. Wnt (talk) 01:26, 29 November 2016 (UTC)

Yes, the dye is a fluorescein derivative and it tends to be a very stable structure because its highly halogenated. I don't know either if bleach would help. When my friend bleaches his white dress shirts, if a touch of dilute bleach and an adequate quantity of hydrogen peroxide fails on a stain, he'll apply the dilute bleach then a drop of lemon juice or vinegar and then the peroxide. Unfortunately, this combination of bleach and acid liberates toxic chlorine gas which can be lethal in quantity, why you should not mix bleach and vinegar, until its stopped by the H₂O₂ . In fact, it is this unpleasant gas that you smell when CO₂ in the atmosphere reacts with the bleach solution. -Modocc (talk) 02:34, 29 November 2016 (UTC)

When laundering, a few minutes before washing I'll often use toilet bowl cleaner on the worst stains because the soil here has a lot of iron oxides in it. Sometimes only pure soup and a lot of heavy brushing gets whatever I happened to get into out. --Modocc (talk) 05:21, 29 November 2016 (UTC)

Ah - yes fluorescein - from the little chemistry I know, that sounds like bad news.  :-( With a dye that's as stable as that, it's likely to be as stable as the dyes that we don't want to destroy in the original carpet. Having a white patch on an oatmeal carpet would be at least as bad as a pink patch! SteveBaker (talk) 14:47, 29 November 2016 (UTC)

A white patch or any fading or damage to the original carpet would be bad. My friend and I have used this peroxide stopping technique on various carpets without causing that problem. The key factor is to not let the bleach react with the carpet for any length of time (on clothes after a few minutes it will turn it white and even eat holes in it too, also, undiluted bleach will do this in mere seconds so you have to slow the reaction down with dilution). To gain confidence and get the hang of it, you could try this on old clothes and carpets that you don't care about so you can estimate what to expect. Since you have to be quick with the peroxide, it helps to limit the size of area that you are targeting to something manageable. --Modocc (talk) 15:23, 29 November 2016 (UTC)

I suspect that even if you succeed in removing the colour of the stain without bleaching the carpet's colour, the area involved will always show a noticeably changed texture. I suppose you've considered just putting a rug over the stain? {The poster formerly known as 87.81.1230.195} 176.248.159.54 (talk) 08:20, 29 November 2016 (UTC)

Sadly, the "put a rug over the stain" doesn't really work here because it's right by the door as you step into the room...but something of that nature seems necessary here. SteveBaker (talk) 14:47, 29 November 2016 (UTC)

I suggested to my wife that we smear kids toothpaste all over the carpet and dye it all the same shade of pink!

This did not go over well!  :-)

New rule: Anything with Red 28 in it does NOT get into our house anymore! We'll be switching to kids' toothpaste with regular food dyes that are easy to get off in case of another "tea party" related disaster! (And also putting toothpaste into a cabinet that's out of kid's reach!)

Thanks for all the help! SteveBaker (talk) 14:47, 29 November 2016 (UTC)

You may have already found this, but one of the primary uses of Red 28 is to dye fabrics. In fact it is somewhat famous as one of the first modern dyes that didn't require a secondary fixative. All of which suggests you are pretty screwed. There are industrial systems for degrading Red 28, especially in the waste water from dye operations, but most of those are either going to be inappropriate or inaccessible. The only thing that comes to mind that you might consider is that prolonged exposure (hours) to UV light will degrade the dye especially is combined with activation agent like H2O2 or an aqueous suspension of powdered TiO2. However, I would suspect that anything strong enough to destroy Red 28 is going to fade the other dyes in your carpet. Depending on personal preference a larger whitish stain might be preferable to a small pink one. If you do try UV, at least there is the potential to illuminate it narrowly on the stain, which may allow for better targeting than bleach. If your carpet is a uniform color (rather than patterned) you might be able to excise the affected region and apply an inconspicuous patch. However, be warned that it takes a lot of skill to patch carpet in a way that looks good. Poor to middling efforts tend to be very conspicuous. Dragons flight (talk) 15:32, 29 November 2016 (UTC)

I realized after reading Modocc's comments below that I was apparently thinking of the wrong "Red 28". I had in mind "Direct Red 28" (aka Congo red) [2], which is apparently different from "FD&C Red 28". Sorry for any confusion. Dragons flight (talk) 09:05, 30 November 2016 (UTC)

Another option: a professional carpet cleaner outfit may have what's needed to clean it. The dye is soluble so there is hope, and the newer carpet fabrics are made to be more stain resistant, so its possible the dye has not yet fixed such that its indelible, but after already using various solvents and a hot iron on it... -Modocc (talk) 16:23, 29 November 2016 (UTC)

This data sheet of the compound list different manufacture names for the compound: [3] which should help us find out more about it. It has two table entries for color fastness against light: 1 and fading from soaping: 3. But I haven't found what these AATCC values mean yet. OK this source states that "Lightfastness is judged on a scale of 1 to 8, where 8 is most fade-resistant. Washfastness is judged on a scale of 1 to 5, where 5 is most resistant to washing out." I can't find mention of the AATCC and it does not list this dye (you would think it would be, errrrr). But assuming these are the scales being used having respective values one and three, it is very susceptible to light as Dragons flight pointed out above and will fade anyway with repeated washings. --Modocc (talk) 17:54, 29 November 2016 (UTC)

Turns out we do have an article on this dye, its called Phloxine. It states "For humans, the Food and Drug Administration deems phloxine B to be safe up to a daily dosage of 1.25 mg/kg." This Handbook of Biological Dyes and Stains: Synthesis and Industrial Applications lists it as Phloxine B. --Modocc (talk) 20:29, 29 November 2016 (UTC)

Good news, the Dictionary of the Coal Tar Colours states that this dye is not colorfast; confirming what I found above in this source. In other words, a moderate amount of light and washings should make a noticeable difference without affecting the carpet's more durable dyes. --Modocc (talk) 22:23, 29 November 2016 (UTC)

What is the common denominator of all the lipids?

I've read the article here, but I couldn't understand the answer and I'll explain why. In biochemistry we have monomers and polymers while the monomer is the basic unit molecule for the polymere. In protein for example, we have amino acid that this is the basic unit of the proteins. Amino acid is characterized as structure of 4 groups: Alpha carbon, amine group, carboxylic group, hydrogen and R chain. this is the basic of all the amino acids. But when we are talking about lipid as a main family of molecules (like what we have we have with protein) then I can not understand what is "amino acids" (parallel) of them, i.e. what is the basic unit of the lipids and what is the structure. Well, I could understand that the fatty acids are the analogous for the amino acids, but the problem is that fatty acids according the article (and other schemes that I saw on google pictures), they are considered as subgroup of the lipids, and that says that not all of the lipids are made of them. So I don't have clue for the answer to my question. 93.126.88.30 (talk) 21:07, 28 November 2016 (UTC)

Unlike amino acids, lipids as a group don't have a common structural definition. They are defined by certain properties rather than by structure, in particular the properties of being insoluble in water but soluble in certain nonpolar organic liquids. Looie496 (talk) 21:31, 28 November 2016 (UTC)

Yes, there are some odd "lipids" like cholesterol. But most "lipids" in the body are triglycerides, phospholipids and glycosylated derivatives of those, which have a fairly consistent structure. Blythwood (talk) 23:02, 28 November 2016 (UTC)

The definition of "lipides" apparently traces back to this article [4] from 1925. Needless to say, as always with ACS, they're demanding credentials to access the content. Aaron Swartz could have suggested something here. In general note that biological terms are typically defined historically and procedurally (though not infrequently they are redefined, which can add to the fun) - an enzyme is defined as an activity that converts one chemical to another in an assay, an allele is defined in terms of how it affects an organism. It came as a pretty big surprise over the years that so many of these things turned out to have a straightforward physical basis, most of the time. Wnt (talk) 01:00, 29 November 2016 (UTC)

@Wnt: They aren't really demanding credentials so much as payment, either in the individual case or through some academic affiliation. Subtle distinction, and yes, it is bullshit, but let's at least recognize that un-credentialed are welcome to read if they pay enough (for an article whose author, as well as original editors and publishing staff are all dead).

Anyway, the definition of 'lipides' given there is:

“ Substances having the following characteristics : as ether, chloroform, benzene. potential. a. Insolubility in water and solubility in the fat solvents, such b. Relationship to the fatty acids as esters, either actual or c. Utilization by living organisms. Fats-esters of the fatty acids with glycerol. Waxes-esters of the fatty acids with alcohols other than glycerol. Compound lipides. Esters of the fatty acids containing groups in addition to an alcohol and fatty acid. Phospholipides-substituted fats containing phosphoric acid and nitrogen-lecithin, cephalin, spingomyelin. Glycolipides-compounds of the fatty acids with a carbohy- drate and containing nitrogen but no phosphoric acid- cerebrosides. Aminolipides, s’ulfolipides, etc.-groups which are at present : not sufficiently well characterized for classification. Derived lipides. Substances derived from the above groups by hydrolysis. Simple lipides. Esters of the fatty acids with various alcohols. Fatty acids of various series. Sterols-mostly large molecular alcohols, found in nature combined with the fatty acids and which are soluble in the fat solvents-cholesterol ( C2,H4,0H), myricil alcohol (C30He10H), cetyl alcohol (CXH~~OH), etc. ”

Apologies for formatting; I'm happy to provide a pdf of the article to anyone who is interested. SemanticMantis (talk) 16:16, 30 November 2016 (UTC)

Stubborn fat???

Is some fat stubborn? Like visceral fat being more difficult to get rid off than subcutaneous fat?? — Preceding unsigned comment added by 31.4.136.234 (talk) 23:28, 28 November 2016 (UTC)

A detailed reading of our articles Adipose tissue and Abdominal obesity does not give a clear cut answer, but suggests that it is difficult to target specific areas or types of fat rather than the body's fat overall (see also Spot reduction).

After reading those articles, you might want to investigate some of the further links in their "See also" sections. {The poster formerly known as 87.81.230.195} 176.248.159.54 (talk) 17:23, 30 November 2016 (UTC)