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Talk:Caffeine

Pardon me for not keeping track, but what was the decision on images in wikipedia for things like molecule structures? I've just sent Larry a .png I created of the caffeine molecule, b/c the transcription on the main page looks so foreign to what I'm used to seeing--but I'm not a chemist, nor did I progress beyond CHM 2400. :-) Should we create our own images, or handle it through ASCII art? The advantage of images would be that some vandal can't come in and change, say, an "H" to a "C" and slip it through. The disadvantage is that some professor can't come in and change, say, an "H" to a "C" and have it be duly noticed. Also, the images won't display in text browsers. Opinions? --KQ

Without images, the web wouldn't be what it is; I say, go for the images.

Yay! that's the quickest turnaround on any request for a new entry that *I've* ever made! MichaelTinkler, caffeine-addict

That's because you're not the only caffeine addict here. :) -- Taw (who started Caffeine entry and is proud of it).

KQ, a professor could still come in and make a note that the depiction isn't right, and someone could just then go fix it and repost it. Right?

That's true I guess. The .png doesn't show up in IE 5.0 tho (or Opera 5.01), for some reason. It works in Photoshop, Irfanview, and NS 6.1. Any suggestions? Lee? Optimum format, preferences to toggle, etc.? --Koyaanis Qatsi

What PNG? IE 5.0 should be fine (See, for example, http://www.libpng.org/pub/png/pngsuite (http://www.libpng.org/pub/png/pngsuite) to verify your browser). If you can give me a URL for the actual file you're talking about, I'll see if it is a correctly coded image file. --LDC

The reason it doesn't show might be that there's no link in the article... --Magnus Manske

Since I can't work out (from the discusion above) whether anybody has actually made an image, I went ahead and made one for my favourite molecule. BTW I'm not really a chemist so I used the ASCII structure as a reference, somebody else should check it. -- DrBob

I have made an image, which I emailed to Larry, but I did something wrong and it doesn't work in IE 5.0. I'll send it to LDC so he can point out what I've done wrong, but right now I'm at work and the image is at home. Thanks for making an image of your own, but the diagram leaves out the individual carbon atoms, and also has a shape different from how it's usually drawn, because it's based on the ASCII art, which is limited to pipes and slashes to indicate bonds. I'll send the image to LDC tonight when I get home. --Koyaanis Qatsi

It was my impression that in schematic diagrams like this is was traditional to leave out the carbon atoms rather than clutter the diagram with what is otherwise obvious. Of course a more pictorial representation (such as a ray-traced picture with spherical atoms) has to leave them in. --LDC

Well, it's been a long time since CHM, but the only atoms I remember leaving out were the hydrogen ones. Is it customary to leave out the carbons, too? Anyone? --KQ

Well, I thought it was, which is why I left them out in the first place. I've certainly seen diagrams printed that way. But as I say, I'm not a chemist. -- DrBob

I'm seeing it half and half on a google image search. Maybe a chemist can come explain to us laypeople. :-) --KQ

There are lots of carbons in lots of compounds. We leave them out as often as possible -BUT we know what we are talking about. That may not hold for a general audience. -A chemist.

As a to-be-biochemist, it looks good to me. Definitely sufficient. --Magnus Manske

I'm not a chemist, or looking to be one, and it definitely wouldn't have been clear to me. Who is your audience, anyway?

We can't teach all of chemistry in the caffeine article, don't you agree? Those who know what the image means (at least roughly;) will welcome it, and the others should take a chemistry class! The image is additional, it is not the central part of the article. But, if you (whoever you are) would like to start a "how to learn chemistry" wiki, go ahead, I will contribute when I have some time :) --Magnus Manske

I'm not sure I agree. I know what the image means, but I wouldn't have guessed that there were Carbons at the intersection of each 4 bonds without a letter there--though, with the C listed, I could tell you that the C stood for Carbon. Is it a stylistic matter (some of the images do show the C)? --KQ

In chemistry texts, carbon atoms in rings are left out more often than not, especially aromatic rings like benzene but other rings as well, and occasionally in straight chains. The only real exceptions are when you want to point out optical activity and when you want to make it really, really plain what is happening. I think it would be better to explain the convention somewhere than to try and put carbons in everywhere - consider what will happen with chlorophyll and heme.

For a practical example when to draw carbons, see [1] (http://www.chemheritage.org/EducationalServices/pharm/asp/draw.htm) for aspirin drawn with and without carbon atoms. I think the initial remark was about "images of Lewis structures are too complicated for the unwashed masses", though. Or am I mistaken? --Magnus Manske

That ring (the benzene ring) is, as they say, so common that it is usually drawn like that, but if you'll notice, the Carbons are still indicated in the attached molecule. --KQ

That's because the attachment is a straight chain, corresponding to the CH₃ groups here, where carbon are shown. It is fairly rare, though not unheard of in larger molecules, for carbons to be omitted in straight chains, since it isn't quite as clear how to replace them.

Here's the image KQ sent; I don't have any particular preference, but someone might.

Tuxisuau - toxicity is measured using a measurement called LD50 (Lethal dose for 50% of a population), and so the use of the term half the population is actually correct. I am going to change back for now, but please feel free to add info to the discussion. Thanks Ddroar

Ddroar - Ok, then u're right. But if u know about LD50, it will be better to add some reference to it (as u can see, i had no idea, so I invite u to write it) (Tuxisuau)

Ok, I just looked up "mateine" in response to the claim that yerba mate doesn't have caffeine, but a similar chemical compound called "mateine." I found 132 results in google, most of them in fringe or alternative publications. I'd feel much better about it if we had some backing from a recognized authority, such as a peer-reviewed scientific journal. Koyaanis Qatsi, Monday, April 1, 2002

it does not have it... i just checked all the 4 diff. types of mate packages i found at home now; they have all the other things like potassium content specified; no caffeine... as far as you won't find the mate in your supermarket i suppose you wont find the non-recognised articles either. try some of these: http://www.lasmarias.com.ar/ilayerba_nut.htm http://www.yerbamate.co.uk/pages/page10.htm Zisa

I will find mate in my supermarket, and my package (Yogi Green tea mate) says it contains 44mg caffeine per cup. The Yogie mint mate says "7.5 mg" per cup, so I'm guessing that mate itself has at least 7.5 mg caffeine, as it's commonly understood. Thanks for the links though. Koyaanis Qatsi, Monday, April 1, 2002

okay... the mates i have found here i have bought in uk, italy and argentina and in none of these packets i have found any mgs or mentions of caffeine, instead e.x. taragui mate has specified its kcals, proteines, lipides, glucidos, fibers, pantonine acids, riboflavine, potasium, magnesium and other minerals. Zisa btw, 'green tea mate' is partly green tea and partly yerba or pure mate?

Partly green tea and partly mate. But the green tea mate' (w/ 7.5mg caffeine [or mateine]) has no other caffeine-containing ingredient. I think LDC, below, is on to somethine when he suggests we let scientists come to a conclusion on it, then just report what they determine. cheers, Koyaanis Qatsi

I changed the Yerba Mate page; for this page, though, I think it's fine to just leave out any mention of mate. It's not really critical to describing caffeine as such, and it avoids having to change the article when later research finally decides the question. -- Lee Daniel Crocker

That sounds like a good approach. Koyaanis Qatsi

How and why does caffeine stimulate the nervous system? AxelBoldt

Could the person who posted the 3D caffeine picture please shrink and crop it -- it's larger than my monitor!
Also, if you didn't use freeware to produce the caffeine model, you probably need to mention the name of the software (I know you do, if it's from Insight II, since I used to work at Accelrys when it was MSI). -- Marj Tiefert, Tuesday, April 2, 2002

I'll even do some of the work for you--I'll crop it and shrink it when I get home tonight. But it still probably ought to be attributed. --LDC

I temporarily removed said picture (uploaded by Little_guru) from the article. For the curious, here it is again:

I think a 3d picture of caffeine (and indeed of all important molecules, especially water) are very desirable. They can be made easily with the free software RasMol: http://www.umass.edu/microbio/rasmol/ In order to render a molecule, you need a coordinate file; these are also widely available for free on many sites. AxelBoldt

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