Chemistry Blog

Jan 30

Wellcome chemical images


The UK’s leading medical research charity, the Wellcome Trust, have donated a treasure trove to the world; 100,000 images covering the history of all aspects of medicine, science and technology are now freely available to any and all.

The database contains pictures of weird and wonderful medical instruments, copies of historical documents and stunning examples of science related works of art from Van Goghs to cartoons. It’s a joy just to peruse the library jumping from one fascinating image to the next. But, being a chemist, I was of course, particularly drawn to the documents and apparatus depicting the history of my chosen field.

Take the paraphernalia of the great and the good which gives a wonderful insight into their lives, working habits and personalities.

Of course Watson and Crick are well represented. There’s the draft of their famous paper describing the double helix of DNA, complete with hand written notes and annotations. But a better testament to Crick’s temperament and modesty is a photo of some graffiti allegedly scrawled by him. It seems to be part of a exchange with Enoch [Powell?] whilst also suggesting Crick may have had ambitions beyond a mere Nobel Prize.

Francis Crick’s graffiti, date unknown

Francis Crick wall graffiti Credit: Wellcome Library, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Francis Crick wall graffiti, Location and date unknown 'Keep the Lefties Out. Crick for God' Crick Papers Published:  -  Copyrighted work available under Creative Commons by-nc 2.0 UK, see http://wellcomeimages.org/indexplus/page/Prices.html

Credit: Wellcome Library, London. Wellcome Images
Copyrighted work available under Creative Commons by-nc 2.0 UK,

 

There’s plenty of material on double Nobel Laurette, Marie Curie. Images of her laboratory are fascinating insight into her practices.

However, it’s her scruffy laboratory notebook that I find most interesting. Madam Curie was certainly a genius but her notes probably won’t pass muster with most PhD supervisors today.

Pages from Marie Curie’s notebook 27 May 1899 – 4 December 1902 

redit: Wellcome Library, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Page from notebook. 27 May 1899 - 4 December 1902 Holograph note-book containing notes of experiments, etc. on radio-active substances. Marie Curie Published:  -  Copyrighted work available under Creative Commons by-nc 2.0 UK, see http://wellcomeimages.org/indexplus/page/Prices.html

Credit: Wellcome Library, London. Wellcome Images
Copyrighted work available under Creative Commons by-nc 2.0 UK

 

Then there’s the equipment that highlights how science has progressed.

Take the X-ray spectrometer lovingly developed by the Leeds physicist William Henry Bragg. The 100 year old device is  the direct ancestor of equipment housed at synchrotron like the massive Diamond light source.

Bragg’s X-ray Spectrometer 1910-1926

Bragg X-ray spectrometer, England Credit: Science Museum, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Bragg X-ray spectrometer, England, 1910-1926 Developed by William Henry Bragg (1862-1942), a professor of physics based in Leeds, England, this X-ray spectrometer was used by him and his son William Lawrence Bragg (1890-1971) to investigate the structure of crystals. The Braggs developed new tools and techniques to understand crystals. Their research was the basis of ¬X-ray crystallography, a technique that was used to advance chemistry, physics and biology. The Braggs won the Nobel Prize for Physics in 1915. 1910-1926 Published:  -  Copyrighted work available under Creative Commons by-nc-nd 2.0 UK, see http://wellcomeimages.org/indexplus/page/Prices.html

Credit: Science Museum, London. Wellcome Images
Copyrighted work available under Creative Commons by-nc-nd 2.0 UK

Or the penicillin fermentation vessel, one of thousands originally used by Glaxo (now GlaxoSmithKline) to grow the penicillium mould from which the antibiotic was extracted. Later the mould was grown in fermentors. Now of course the antibiotics are made synthetically.

Penicillin fermentation vessel, 1940-45

Credit: Science Museum, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Penicillin fermentation vessel, England, 1940-1945 Thousands of glass fermentation vessels like this one were used in Glaxo (now GlaxoSmithKline) laboratories to produce penicillin. The penicillium mould was grown on the surface of a liquid filled with all the nutrients it needed. This approach was superseded by the method of growing the mould within large industrial fermenters. The antibiotic was first used in the early 1940s and saved the lives of many soldiers during the Second World War. 1940-1945 Published:  -  Copyrighted work available under Creative Commons by-nc-nd 2.0 UK, see http://wellcomeimages.org/indexplus/page/Prices.html

Credit: Science Museum, London. Wellcome Images
Copyrighted work available under Creative Commons by-nc-nd 2.0 UK

And there’s a wealth of early infographics, like this table of chemical characteristics from 1799, which predates the modern periodic table and chemical notation. Instead the elements (along with light and combustion) have been given symbols which are then combined to represent the compounds formed when these element are reacted together. The result is a beautiful if confusing representation of the state of chemistry in the 18th century.

 

Chemistry: symbols of elements and substances. Coloured engraving by H. Ashby, 1799, after W. Jackson. 

Chemistry: symbols of elements and substances. Coloured engr Credit: Wellcome Library, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Chemistry: symbols of elements and substances. Coloured engraving by H. Ashby, 1799, after W. Jackson. 1799 By: William Jacksonafter: Henry AshbyPublished: 26 October 1799 Copyrighted work available under Creative Commons by-nc 2.0 UK, see http://wellcomeimages.org/indexplus/page/Prices.html

Credit: Wellcome Library, London. Wellcome Images
. Coloured engraving by H. Ashby, 1799, after W. Jackson.
1799 By: William Jacksonafter: Henry AshbyPublished: 26 October 1799
Copyrighted work available under Creative Commons by-nc 2.0 UK

Finally the mundane but no less fascinating. How about a cunning 3D representation of the periodic table lovingly mounted in a jam jar!

L0002952 Model showing Periodic Elements of Chemistry Credit: Wellcome Library, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Model showing Periodic Elements of Chemistry. From a model prepared at the Royal Institute of Chemistry Published:  -  Copyrighted work available under Creative Commons by-nc 2.0 UK, see http://wellcomeimages.org/indexplus/page/Prices.html

Credit: Wellcome Library, London. Wellcome Images From a model prepared at the Royal Institute of ChemistryCopyrighted work available under Creative Commons by-nc 2.0 UK 

 

This post originally appeared in the Guardian.

Jan 28

Yes, there are chemicals in the shampoo!


‘Organic’ cosmetics manufacturers, the very epicentre of chemophobia, right? All those ‘chemical-free’ bottles of deodorants, shampoos and hair dyes.  It makes you want to pull your hair out just so there’s no need for their nonsensical products.  And here’s the latest from Daniel Field Organic and Mineral Hairdressing, tucked away in the FAQs is this gem.

Are there any chemicals in Daniel’s Watercolour [hair dyes]?

This is a question we are often asked and understandably so because there has been much discussion concerning the term “chemicals”.

Wait for it….

Many materials – both natural and man-made have a definite chemical composition; a common example of a chemical substance is pure water (H20) and so no manufacturer can claim that any product is devoid of chemicals – in fact all matter is made up of chemicals.

Well, that’s a turn up for the books!

And there’s more, the ingredients FAQs don’t shy away from ‘scary’ sounding names.

The nine ingredients for the dye pigments are as follows, followed by their safety ratings:

i. p-toluene diamine sulphate – PTDS

ii. m-amino phenol sulphate

iii. 2.4 diaminophenoxyethanol hcl

iv. p-aminophenol sulpahte

v. 4-amino 2 hydroxytoluene sulphate

vi. 4-amino -m-creosol

vii. 2-amino 6-chloro -4-nitrophenol

viii. 2-methyl-5-hydroxyethylaminophenol

ix. 4.5 diamino-1-(2-hydroxyethyl) pyrazole sulphate

 

Plus there’s real advice on the safety of each of the above.

All in all its very sensible. So bravo to Daniel Field, very well done indeed (edit: honestly no sarcasm here I really do think they’ve done a good job) ! You win the 1st Chemistry-Blog award for sensible chemistry information on an ‘organic’ product.

Now, what colour shall I have my hair?

 

 

 

Hat tip to @corrineburns

Jan 26

Molecule of the day with a difference


Everyday Zoë Waller posts a drawing of a molecule on her twitter feed. A quick trawl pulls up others who do similar.  But Zoë’s uses a rather unusual canvass … herself. She doesn’t graffiti herself with ink, instead she takes advantage of her unusual skin.

 

Zoë has dermatographia, a condition which results in her skin releasing histamines  in response to physical pressure. This manifests as an apparent mild allergic response, with localised swelling when she scratches herself.  The effect fadesafter about 30 minutes, but that’s plenty of time to use a her favourite bamboo skewer, or tablet stylus to doodle a molecule on her skin.

 

And the results are fascinating insight into the molecules that Zoë, as a chemical biologist comes across.

 

There’s allicin the molecule responsible for garlic smells.

Allicin

 

Capsaicin for those that like it hot,

 

Capsaicin

 

and lycopene, the red pigment from tomatoes

 

Lycopene

She’s also done macromolecules,

 

SP1, transcription factor

 

or the intricate oxytocin.

 

Oxytocin

 

And, many, many more.
Make sure you follow Zoë’s tweets for daily updates. And she even does request.

Jan 18

Photo Friday (#picpickoftheweek)


My graduate student, Sean Hill, became the Hanson Research Group twitter account manager last week. We first talked about what is and isn’t acceptable to post on the internet. Then Sean explained to me the nuances of hash tags and how I’ve underutilized them.  He also suggested something brilliant: a photo of the week.

One of the things I like most about doing research in molecular photophysics is the beautiful color chemistry. Now, every Friday, Sean will tweet (#picpickoftheweek) our best photo taken during the prior week. Our first image (below) is very fun and depicts a photon upconversion solution.

Upconversion

This image shows green laser pointer light (532 nm) causing blue (~430 nm) emission from the solution.  What makes this image really interesting, from a photophysics standpoint, is that we’re  observing the conversion of lower energy green photons into higher energy blue photons.

The reverse—higher energy blue light turning into lower energy green light—is easy. Many molecules absorb a single high energy photon and then emit a single lower energy photon with some energy lost in the process due to vibrational relaxation.  The more difficult green-to-blue light change depicted above is only possible if we combine the energy from two green photons to produce one higher energy blue photon.  This process is known as photon upconversion.

While it can be observed in inorganic nanoparticles, the solution above is a mixture of two types of molecules that undergo excitation, energy transfer, triplet-triplet annihilation and then emission.  Our research group is interested in studying these upconversion systems because they could potentially provide a mechanism to harness low energy light and increase the theoretical maximum solar cell efficiency from 33% to >40%. If you’re interested in learning more about photon upconversion through triplet-triplet annihilation, here is a good review article.

Follow us, @HansonFSU, on twitter for more molecular color chemistry.

Dec 31

Garlic Challenge, the results show!


Back in October I posed a question: Is there any truth in the old wives tale that rubbing your hands on stainless steel gets rid of garlic smells? Various theories as to how steel may achieve this were posited. But I wanted to know if there was a real effect in the first place. Kitchen chemists everywhere helped answer this by taking part in a stinky citizen science challenge. And the results are, well, interesting.

Garlic

I asked people to conduct a quick experiment whilst prepping dinner. The task was simply to rub the palms of their hands with garlic. Then treat one hand with a wipe from a stainless steel spoon and the other with a wooden spoon. Finally participants asked some other poor soul to take a sniff of their hands and report on whether there was a discernible difference.

Thanks to everyone who took up the garlic challenge (especially the person who did their experimenting whilst cooking Christmas dinner).

And so to the results.

These were collected via surveymonkey, with the question “Which hand smelt more of garlic?” and the answer choices a) The hand rubbed with the wooden spoon, b) The hand rubbed with the stainless steel spoon, c) Couldn’t tell the difference.

44 allium lovers responded. Of those 17 thought the hand treated with the wooden spoon smelt more garlicky, 6 said the stainless steel treated hand was the stinkier. So far, so good. Looks like the stainless steel effect might be real. But here’s the rub, there’s still the other 21 responses, none of whom could tell the difference between the smelly hands.

 

Screen Shot 2013-12-31 at 10.48.37

 

So we’ve got results that are significantly different from an even distribution between the options (the two-tailed P value equals 0.0163 ,according to a chi squared test) . However, the stainless steel treatment seems to be only about 38% effective, assuming the wooden spoon is a good negative control. But maybe the abrasive, absorbent wooden spoon is also quite good at removing garlic smells? In which case the effectiveness of the stainless steel is an underestimate.

Oh well, sorry people, but it looks like I can’t really offer a definitive answer. In hind sight I think the experimental design could have been better. A before and after spoon treatment sniff test would have been a good idea. And maybe a better negative control was in order.

Looks like another round of experiments  could be in order. Or can anyone offer a better way of analysing the data (I suspect sensitivity vs specificity analysis might be more appropriate)?

Dec 20

And From the Other Side of the Pond… We Wish You a…


MerryChristmas

And from reader Darwin, a 3D version!

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