Education

What can Sugru do for scientists?

Chemistry World blog (RSC) - 9 hours 13 min ago

Looking around Form Form Form’s laboratory in Hackney, London, you can’t help but notice that the standard lab equipment has been modified, tweaked, personalised and adjusted using Sugru – the mouldable silicone rubber adhesive they manufacture. When I went to visit them with Phillip Broadwith, Chemistry World‘s business editor, to learn about the history and chemistry of Sugru, we asked a simple question: ‘what can Sugru do for scientists?’

Jude Pullen, head of R&D, took us through a handful of ‘lab hacks’ – quick and simple ways to make lab equipment safer, more efficient and easier to use:

Can you think of a way to use Sugru in the lab? Let us know by commenting below, or find us on Twitter: @ChemistryWorld

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Ideal Gas Law Simulation

Merlot chemistry - 15 hours 30 min ago
An effective tool to help students learn about all aspects of the ideal gas law. One of the best web gas law simulations.
Categories: Education

Assessing Blood Pressure

Merlot chemistry - 15 hours 30 min ago
This learning module presents the proper technique and common errors associated with assessment of blood pressure. The information is targeted at new learners in the clinical and health sciences and can serve as a review for current practitioners. The program includes audio of blood pressure sounds, interactive simulations, and self-assessment tools.
Categories: Education

DNA from the Beginning

Merlot chemistry - 15 hours 30 min ago
DNA from the Beginning is an animated tutorial on DNA, genes and heredity. The science behind each concept is explained using animations related to DNA topics, an image gallery, video interviews, problems, biographies, and links related to DNA. There are three sections, Classical Genetics, Molecules of Genetics and Organization of Genetic Material. Key features are the clear explanations of classical experiments and the excellent photographs of researchers and their labs.For information and credits on the development of DNA from the Beginning, go to http://www.dnaftb.org/dnaftb/credits.html
Categories: Education

VR Molecules

Merlot chemistry - 15 hours 30 min ago
VR Molecules presents dynamically and interactively the vibration and rotation modes for 24 molecules (out of a more extensive list) containing up to twelve atoms. It allows the user to create and save on his or her hard disk documents containing, much in the same way as Power Point presentations, up to 10 "pages״, each featuring one or two molecules with specific parameters (viewpoint, active modes, etc.). These presentations can be made available through the Internet, with optional sound and text explanations associated with each page.The latest, augmented version of VR Molecules, called VR Molecules Pro 1.1, is available online as well as in a stand-alone version (Mac and Windows). To view a video of the award winning author, go to View VR Molecules - Chemistry Award Winner 2007 video VR Molécules est un logiciel de simulation (en ligne et en mode local) permettant de visualiser et d'explorer les modes de vibration et de rotation des molécules (24 molécules sont disponibles). Il peut tout aussi bien être utilisé par le professeur pour préparer des démonstrations en classe, intégrer des animations (interactives ou non) dans ses documents HTML, que par les étudiants pour revoir les démonstrations présentées en classe et explorer par eux-mêmes la vibration et la rotation des molécules.La plus récente version (1.12) de VR Molécules, est accessible en deux versions : en ligne et en mode local (à télécharger, pour Mac et Windows).
Categories: Education

Neuroscience for Kids

Merlot chemistry - 15 hours 30 min ago
The entry point to an extensive site concerning the nervous system and neuroscience. The site includes descriptive materials, experiments, activities, links to articles, resources for teaching neuroscience, and a listing of Internet resources related to the neurosciences.
Categories: Education

Virtual Chemistry Laboratory

Merlot chemistry - 15 hours 30 min ago
Here's your chance to mix chemicals without wearing safety goggles. You won't spill any acid on the spectrometer in this lab. Choose solutions from the vast database and mix 'em together till the cloned cows come home. Marvel as the chemical solutions react in real time.
Categories: Education

PhET - Physics Education Technology at the University of Colorado

Merlot chemistry - 15 hours 30 min ago
A collection of simulations and virtual labs focusing on first-year college physics. An interview with the award winning author can be found in About us at Phet VideoPhET provides fun, interactive, research-based simulations of physical phenomena for free. We believe that our research-based approach- incorporating findings from prior research and our own testing- enables students to make connections between real-life phenomena and the underlying science, deepening their understanding and appreciation of the physical world. To help students visually comprehend concepts, PhET simulations animate what is invisible to the eye through the use of graphics and intuitive controls such as click-and-drag manipulation, sliders and radio buttons. In order to further encourage quantitative exploration, the simulations also offer measurement instruments including rulers, stop-watches, voltmeters and thermometers. As the user manipulates these interactive tools, responses are immediately animated thus effectively illustrating cause-and-effect relationships as well as multiple linked representations (motion of the objects, graphs, number readouts, etc.) PhET Interactive Simulations, University of Colorado, http://phet.colorado.edu
Categories: Education

Physlets

Merlot chemistry - 15 hours 30 min ago
Educational physics applets designed to be scripted in JavaScript for use in quizzes, homework problems, and Just in Time Teaching activities. Includes applets that can be used in a wide range of classes and at different levels.
Categories: Education

Music Acoustics

Merlot chemistry - 15 hours 30 min ago
The acoustics of musical instruments and the voice. The "Basics" directory introduces and explains general concepts. There are "Introduction to the Acoustics of [instrument name]״, data bases, technical material, web services (including a hearing test) and a FAQ.
Categories: Education

MecMovies

Merlot chemistry - 15 hours 30 min ago
MecMovies is an extensive collection of examples, theory, and games designed to complement the entire Mechanics of Materials course. The software features impressive graphics and animation that are highly effective in visually communicating course concepts to students. Special emphasis is placed on developing the learner?s understanding and proficiency in basic concepts and skills through interactive exercises and games. Classroom implementation of the software has produced improved student performance and more positive student attitudes regarding the Mechanics of Materials course. To see a video with the award winning author, go to View MecMovies video
Categories: Education

Is it a bird? Is it a plane? No, it’s Raney Cobalt-man!

Chemistry World blog (RSC) - 16 October, 2014 - 16:46

Guest post from Tom Branson

In a bold move by Organic and Biomolecular Chemistry, the journal has unveiled the latest superhero in the fight to save the common scientist from the ruthlessness of today’s laboratories.

With great power comes great selectivity

Standing firm with test tube in hand, Raney Cobalt-man is a new character from Catalyst Comics. The star wears a rather tight, bright cobalt blue coloured outfit, reflecting one of the element’s most notorious uses. How Raney Cobalt-man gained his powers, we will never know. But perhaps it was in a careless lab accident, and if so, he has certainly learnt his lesson. Now with goggles and elbow-length gloves (not to mention a full body suit and special groin area protection), Raney Cobalt-man is a true ambassador for PPE.

This first adventure takes our hero into the domain of the domino reaction where he’s be helped by his trusty sidekick, Dihydrogen Boy. The young assistant plays an essential role in their joint mission to catalyse peace and his support is needed even more as the hero ages. Here in the domino reaction, they join forces to selectively bring harmony cascading through the scientific community.

But where are the other great chemical heroes of today? Well, I suppose there is the elementally named Iron Man – a brilliant scientist, although he was actually more of an engineer. The Flash was first a forensic scientist who came by his powers after a lightning bolt hit his lab. This mishap is, of course, one of the many dangers of working alone late at night. The lovable Chemist Hulk may also be familiar to those folks on Twitter, this mean green scientist likes nothing better than to tweet about ‘SMASHING PUNY MOLECULES’.

Raney Cobalt-man is the hero that chemists deserve, but is it the one they need right now?

In this edition of the Raney Cobalt-man comics, the eponymous hero is helped by Martin Banwell and colleagues from the Australian National University. Together they review an underappreciated reagent and compare its powers to that of its nemesis, Raney Nickel-man. The story tells that high pressure from Dihydrogen Boy can often be off-putting for those wanting to call upon Raney Cobalt-man’s selective powers. But these drawbacks are simply overcome by using a larger amount of Raney Cobalt-man and therefore less of his annoying sidekick.

Comic book and science fans alike may be waiting a while before Raney Cobalt-man’s next adventure hits our book shelves, but be sure to pick up the first edition over at OBC.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

With this ring…

Chemistry World blog (RSC) - 16 October, 2014 - 11:22

Guest post by Jen Dougan

I attended five weddings this year, between February and October, making 2014 most definitely the Year of the Wedding. Each day was unique and reflected closely the couple, their relationship, vision and hopes for the future.  And while there was a broad range of traditions at each, whether religious or humanist approaches, one tradition – the exchange of rings – provided a common element throughout.

The element is, of course, gold. But what is the chemistry of this symbol that is ritually shared as a sign of commitment and lasting love?

© Murray Robertson / Visual Elements

Gold is the most noble of metals, it doesn’t corrode or oxidise in the Earth’s moist, oxygen-rich atmosphere. Ductile and malleable, it can be fashioned at will and, since it doesn’t tarnish, is an ideal material for producing jewellery. The decorative attributes of gold have long been coveted – examples of gold jewellery have been found in the tombs of the Queens of Egypt and Sumeria, 3000 years BC.

Gold is one of only three coloured elemental metals (the others being copper and caesium). Most metals appear whitish-grey as they reflect all wavelengths of visible light. Gold, on the other hand, due to its electronic configuration exhibits a reduction in reflectivity efficiency in the blue region of the visible spectrum. It has, in the pure form, a striking yellow colour and brilliant lustre for which it became known by the latin Aurum, meaning ‘shining dawn’ (depicted by artist Murray Robertson in the image above).

Today the purity of gold jewellery is expressed in terms of ‘karat’. Pure gold is 24 karat, where, K = 24(Masspure/Masstotal), meaning 24/24 parts of the material are gold, by weight. In practice, even 24K gold is often stated as 99.99% pure due to residual impurities from the extraction process. Although 24K gold can be used for jewellery, the softness of pure gold means that alloying the metal to improve its physical properties or to design colour variants is a popular approach. The European standard, for instance, is 18 karat, meaning 18/24 parts are gold (75% pure by weight). The other 25 % of the weight is made up of another material (in the case of jewellery, a second metal) to make an alloy, which is typically stronger than the pure metal.

The improved strength of gold alloys occurs when, having melted two or more metals together, a new structural phase is formed on cooling. The precipitation of the added metal atoms reduces slippage of the original atoms across one another.

Ternary plot of approximate colours of Ag–Au–Cu alloys, which are commonly used in jewellery making.
Original image: Metallos [CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Common alloys of gold for jewellery fall into the yellow gold or white gold categories. Most jewellery alloys of yellow gold, including that of rose and green-shade gold, fall within the Au-Ag-Cu system (see image above). Zn is sometimes added to further increase the alloy strength and to change the red colour of high Cu alloys to a paler rose.

For white gold, Au-Pd-Ag is a common alloy system, where Pd is used as a bleaching agent. Nickel, another metal capable of producing the desired bleaching effect to produce white gold, is a known skin sensitiser and has become less popular in jewellery making.

The bleaching effect occurs due to the added material changing the reflectivity of the alloy in the low energy part of the visible spectrum. In all cases, the relative ratio of the alloy’s components dictate the resulting hue and mechanical characteristics.  The alloy systems allow the characteristics to be achieved such that the design lasts the length of a marriage and beyond.

A word of warning/advice to the newlyweds: although your gold is stable, it is not chemically inert. Avoid exposure to mercury, with which the gold will form an amalgam; cyanide salts, which will react with your band; and aqua regia* in which it will dissolve. Of course, if you encounter any of these three materials by accident, you have greater worries than the integrity of your wedding ring!

The chemical susceptibility of gold for these reagents has proven useful. Mercury and cyanide salts have been used to extract gold from its ore. In fact, gold cyanidation, developed industrially in the 1880s by Glaswegian chemists John Stewart McArthur and Robert and William Forrest is still the main method of gold extraction – and the biggest use of sodium cyanide – globally. The ability of aqua regia to dissolve gold helped foil the Nazis during World War II. Two German Nobel laureates had placed their medals (23K gold) at the Niels Bohr Institute in Copenhagen for safe-keeping. But removing gold from Nazi Germany was a grievous offense and with the laureates names inscribed on the medal, this was an incriminating piece of evidence. ‘While the invading forces marched in the streets’, George de Hevesy – a (future) Nobel laureate himself – dissolved the medals in aqua regia. While the laboratories were laboriously searched by the Nazis, the medals remained dissolved, but undiscovered, on the bench. The metal was recovered after the war and the medals recast and returned to the laureates.

Whatever gold you choose for your wedding band, you add to a rich history of human civilisation fascinated by and adorned with gold. And to the newlywed class of 2014, congratulations!

 

 

* Note: Aqua regia is latin for ‘King’s water’, a 1:3 nitric:hydrochloric acid solution, it is known in Russia as Tsar’s vodka and its ability to dissolve gold is shown wonderfully in this Periodic Table of Videos.

References:

 

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Academic family: the Nobel prize in Chemistry 2014

Chemistry World blog (RSC) - 14 October, 2014 - 14:29

Guest post by JessTheChemist

‘Where the telescope ends, the microscope begins. Which of the two has a grander view?’ – Victor Hugo

In 1873, German physicist Ernst Abbe reported that the resolution limit of the optical microscope was 0.2 micrometres. Although this still remains true, recent work in the field of microscopy – specifically Stimulated Emission Depletion (STED) microscopy and single-molecule microscopy – has allowed scientists to visualise molecules smaller than this limit. This is accomplished by tagging molecules with fluorescent labels, which allows a more detailed picture to be visualised. On Wednesday 8th October 2014 Eric Betzig, Stefan Hell and William Moerner were awarded the Nobel prize in chemistry for their ground-breaking work in ‘the development of super-resolved fluorescence microscopy’. You can learn more about the ins and outs of the Nobel prize winners’ work by reading the recent Chemistry World article.

I am interested in finding out how chemists are connected to each other, and in particular, investigating whether your likelihood of winning a Nobel prize is increased by having a high number of laureates in your family tree.  It is also interesting to see how closely related, if at all, are the scientists that share a prize.

If we consider his academic pedigree, one might say that Eric Betzig was destined to become a Nobel prize winner. He is connected to a number of notable laureates, including the father of nuclear physics, Ernest Rutherford. Rutherford won the Nobel prize for chemistry in 1908 ‘for his investigations into the disintegration of the elements, and the chemistry of radioactive substances’. Through Rutherford, Betzig is also connected to Niels Bohr, who won the Nobel prize for physics in 1922 for ‘his services in the investigation of the structure of atoms and of the radiation emanating from them’.

Additionally, Betzig is academically related to John William Strutt (Lord Rayleigh) who won the prize for physics for the discovery of argon in 1904, along with his collaborator Sir William Ramsay, who won the 1904 chemistry prize for the same discovery. With ancestry like that, Betzig was always destined for greatness.

Alternatively, William Moerner is closely linked to Dudley Herschbach and Yuan T. Lee, who won the 1986 Nobel prize in chemistry ‘for their contributions to the dynamics of chemical elementary processes’. To find out more about Herschbach and Lee’s academic family connections, check out last month’s blog post about one of their connections, Sir Harry Kroto.

Although Eric Betzig and William Moerner worked independently from one another, they both developed single-molecule microscopy, so it is not a surprise that their lineage is intertwined. As you can see from the tree, they are connected via some of the science greats such as Linus Pauling.

Stefan Hell worked in a slightly different field to Betzig and Moerner and, amongst others, is connected to biochemists Robert Huber and Johann Deisenhofer, who won the 1988 Nobel prize for chemistry ‘for the determination of the three-dimensional structure of a photosynthetic reaction centre’.  As predicted, however, all three of the prize winners can be connected through their academic relations – via Deisenhofer, Hell can be connected to Moerner and, therefore, Betzig.

As you can see, all three winners have a rich Nobel history but what I found particularly interesting about this academic family tree is that it contains scientists from all sorts of backgrounds – from nuclear physics to biochemistry to organic chemistry. This led me to think, what kind of scientists am I connected to? To find out what kind of scientists you are connected to, head to academictree.org, where you can add yourself to the website and start creating your very own tree.  You never know who you may be connected to.

And don’t forget to tweet me (@Jessthechemist) with suggestions for the focus of next month’s blog post!

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

September 2014: Newton, sun and ice

Royal Society R.Science - 6 October, 2014 - 16:56

This podcast from the Royal Society has moved.

Please resubscribe to the podcast here:
http://rss.royalsociety.org/podcasts/rscience

Thank you for continuing to subscribe to our updates.
If you have any queries please contact us.

Categories: Education

Is someone drinking the solvents?

Chemistry World blog (RSC) - 2 October, 2014 - 15:46

Guest post by Heather Cassell

Space in the lab is always at a premium; you need more things than you have space for, so it makes sense for multi-group labs to share equipment, consumables and buffer stocks that everyone uses. This inevitably causes trouble when someone doesn’t look after the equipment, or fails to restock things after using them.

It is a frequent problem. You are about to start an experiment, so you’ve checked that the equipment will be free, you’ve planned your samples and now you just need to dilute from a communal buffer stock. All too often there is only a dribble left, so you have to make a fresh stock of buffer before you start, delaying your experiment by precious minutes. Your next stop is the communal chemical stocks, where you find there is either nothing left or such a trifling amount that it is of no use to anyone. This often prompts sarcastic mutterings of ‘how considerate’, or something rather more profane.

In my experience, this is especially common with flammable solvents. As these need to be kept in a special vented cupboard, there is only a limited amount of room for the big brown bottles they are delivered in. The nature of the bottles themselves also conspires to make it all too easy to get caught out: you check in advance that there is a bottle of solvent available, see one in the cupboard and relax into the next task. Of course, when you need it, the brown bottle has concealed the fact that there is only a drop left, never quite enough for what you need to do.

So how does a frustrated chemist deal with this situation? There are several options: you can go to the on-site chemical stores and buy a new one (assuming they are open and have what you need in stock); you can go begging to other groups to see if you can borrow some; or you can simply abandon your half made buffer or experiment and do something else instead.

Even for the renownedly polite English scientist, repeatedly buying a replacement bottle of the same solvent – even though you use only a small amount each time – can test the patience. You end up subtly enquiring to find out who else is using it, so you can politely suggest they stop leaving it in such a maddeningly useless state. Inevitably, your fellow lab denizens will only own up to using a small amount (never a large volume, oh no), and they always leave plenty in the bottle after use.

So where is the rest of the solvent going? As a scientist, I have to rule out untestable hypotheses like ‘the solution magically disappears’. I’ve also never seen a colleague drinking a cup of buffer (though it has occurred to me that they might), so either that isn’t the explanation or they’re very subtle about it. The answers to these questions may never found, but every time it happens you resolve to check more thoroughly before each planned experiment. Until the next time, of course…

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Who will get the 2014 chemistry Nobel?

Chemistry World blog (RSC) - 30 September, 2014 - 15:10

With just under week until the announcements start, Nobel prize fever is officially here.

The official shortlist is shrouded in secrecy, giving those making their predictions about who might win little to go on – but that hasn’t stopped them.

— Nobel medal

As usual, Thomson Reuters have released their Nobel forecast, which uses citation numbers and other statistical wizardry to predict the winners in each category. This approach has successfully predicted 35 Nobel prize winners over the past 12 years.

This time round they highlight three possible chemistry winners – the inventors of the organic light emitting diode (Ching Tang and Steven Van Slyke), RAFT polymerization (Graeme Moad, Ezio Rizzardo, San Thang) and mesoporous materials (Charles Kresge, Ryong Ryoo, Galen Stucky).

Elsewhere, less official speculations – perhaps based more on a hunch – have begun flying around.  On the Everyday Scientist blog, chemist Sam Lord has put together some suggestions. Like the number crunchers at Reuters, Lord has some past successes (though he didn’t predict last year’s computational chemistry winners - Karplus, Levitt and Warshel). He thinks the 2014 prize could go to a key historical invention, such as the contraceptive pill, or the lithium-ion battery (also a top pick for The Curious Wavefunction blogger Ashutosh Jogalekar), but also mentions broader areas such as microfluidics, nanotechnology and next-generation sequencing. If last year is anything to go by, there’s much to be said for gut feeling as well as advanced number crunching. As always, we’ll just have to wait a little longer for that all-important announcement from Sweden.

If you want to get into the Nobel spirit and hear more about the possible winners this year, our features editor Neil Withers joined representatives from Nature Chemistry and C&EN to begin the countdown to the 2014 chemistry Nobel in a Google hangout – watch the whole discussion here.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Nylon – a bit of a stretch

Chemistry World blog (RSC) - 25 September, 2014 - 14:41

Guest post by Rowena Fletcher-Wood

I first heard the story of the discovery of nylon during a chemistry class in school – it was told as a serendipitous discovery. A young lab assistant, clearing up at the end of a long day, clumsily poured two mixtures in together and noticed a precipitate. Dipping in a stirring rod, he pulled out a thin string, which he stretched out into a tough, translucent fibre. He realised the potential of his discovery, reported it to his superiors and left them to the tiresome job of working out what he had done to make it.

The invention of nylon created a revolution in hosiery
©Shutterstock

It’s funny how we use accident to shape our understanding of discovery and achievement, as though we want to excuse hard work and apologise for years of learning. It’s somehow disappointing, unromantic: the story of research whisks away that tantalising fantasy of stumbling upon treasure, reserving discovery for the experts.

The real story of nylon, interesting though it may be, is a bit of stretch from serendipity.

There was a young lab assistant, and his name was Julian Hill. He was working in the DuPont research laboratory, led by the rigorous organic chemist Wallace Hume Carothers, who had taken on the challenging ‘synthetic fibre race’. At the time, synthetic polymers were a mysterious conception; what they were made of and how they related to simpler compounds was unknown. The DuPont team had studied complex natural products such as cellulose and silk and from their understanding had developed polyamides through the condensation of dicarboxylic acids with diamines – fantastically interesting but, at the time, not particularly useful.

Discovery of nylon, 1941 re-enactment. DuPont chemist Julian Hill (1904-1996) carrying out a re-enactment in 1941 of the discovery of nylon in 1935. A glass rod is being used to pull threads from the sample prepared in a glass tube. This discovery was made at DuPont’s Experimental Station near Wilmington, Delaware. Hill was a member of the team, along with other chemists. The molasses-like mass stuck to the glass stirring rod and was drawn out into a thin fibre. After more research and development, DuPont was able to commercialise the new material. Production started in 1939, twelve years after the research program had started in 1927. Credit: Hagley archive/Science Photo Library

Julian Hill had been working with polyester when, dipping in a stirring rod, he pulled out a thin string, which he stretched out into a tough, translucent fibre – just like in the story I was told. But this was not considered extraordinary. Often, discovery is not about observing properties, but recognising them. One day, when Carothers was absent from the lab, the chemists decided to go rogue with the polyester and have a competition to see how long they could stretch it. They raced down the hall, delicately extending the fibre. They had extended it to four times the original length when it stopped. It would not stretch any more.

Suddenly, Hill understood: as they stretched the fibre, chains of molecules snapped into position, orienting themselves into a chain of a discrete thickness. This would be the basis for the first fully synthetic fibres.

But nylon was far from invented. The melting points of the polyesters they had were far too low for any practical applications, and so they returned to polyamides and began stretching those instead. It took 9 months, a patent for the ’cold-drawing’ process of making fibres by removing them from the water of condensation, and 80 new polyamides before the most promising, nylon-6,6, was discovered in May 1934.

Nylon, a dyeable, durable, shiny thermoplastic first entered the market in 1938 as the bristles of a toothbrush, before being appropriated for women’s hosiery in 1940. DuPont declined to trademark the name ‘nylon’, instead allowing it to enter the lexicon as an alternative name for ‘stockings’. The new ‘nylons’ were a huge success. Nowadays, this fantastic fabric, which leaves a lower carbon footprint than wool, is used for meat wrappings, instrument strings and carpets, amongst many other things. Its only downside is its toxicity upon heating: it melts rather than burns, and breaks down to produce hydrogen cyanide.

This is ironic, actually, because Carothers never got to see his creation take hold. In 1937, just as his achievements were being celebrated and developed, he committed suicide with cyanide. He had suffered with depression and was grieving for the loss of his sister, but his suicide came as a shock. The suicide has been described as an ‘embarrassment’ for DuPont, and records relating to Carothers were lost or destroyed. This may help to explain why the discovery of nylon has since been wrapped in myth and mystery.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

A short time ago in a journal not so far, far away…

Chemistry World blog (RSC) - 18 September, 2014 - 14:16

Guest post from Tom Branson

Inside Back Cover: Selective Targeting of Tumor and Stromal Cells By a Nanocarrier System Displaying Lipidated Cathepsin B Inhibitor (Angew. Chem. Int. Ed. 38/2014)
Angewandte Chemie International Edition
Volume 53, Issue 38, pages 10251-10251, 22 JUL 2014
DOI: 10.1002/anie.201406845
http://onlinelibrary.wiley.com/doi/10.1002/anie.201406845/full#car1

Science fiction often predicts future advances and has even prompted the development of some technologies. So should we be taking advantage of this association? Can we use a science fiction setting to showcase science fact? That idea is exactly what the latest cover of Angewandte Chemie has attempted to do.

It’s a trap!

There may be some of you who don’t immediately recognise the image above. It’s an homage to a scene in the Star Wars movies, where the plucky rebel alliance (piloting the small x-wing fighters) mount an attack on the Death Star, a moon-sized weapon of mass destruction and flagship of the evil empire. Hijacking this iconic scene is a certain way to grab the attention (George Lucas himself used it twice), especially by tapping into the current hype for the forthcoming films. But there doesn’t immediately appear to be a solid link between the rebel’s cause and Angewandte’s publishing ideals. In this case I’m not sure if the cover image really works to enhance and explain the research or actually provides a distraction from the science within. It’s certainly a fun image and a good way to get instant recognition of an idea, especially with fans of the franchise. That idea being the destruction of the evil empire, or in this case, evil cells.

In this interpretation the x-wing fighters have their own force fields and are carrying pills towards the Death Star, which itself looks to be in a dire state probably due to the growths in its innards. It should be a straightforward mission as long as the ships watch out for rogue fluorescing cells and a giant-lipidated-space-peptide.

This cover is very similar to an example from 2012 that also showed up in Angewandte. In both cases the empire, represented by the Death Star, took a beating, suggesting that there’s no sympathy for the Sith in the scientific community. For balance, I’d like to see someone’s interpretation of a Death Star nanoparticle destroying the peaceful bacterial population of Alderaan (I will accept joint authorship).

Stay on target

I love all things Star Wars (excluding Jar Jar Binks, of course) but this latest tie in to the franchise does seem a little out of place with the expanded Star Wars universe. No mention of carbonite or even ion cannons. But it does hint at the true content of the article: a new targeted drug delivery method. The group led by Boris Turk and Olga Vasiljeva from the Jožef Stefan Institute in Slovenia, have developed lipid vesicles conjugated to peptides that target extracellular cathepsin B (CtsB). CtsB is a cysteine protease that only translocates to the cell surface during cancer progression and is therefore a cancer-specific target. The research showed fluorophores and anticancer drugs could be transported in their vesicles and target the tumour environment.

For more about targeting cancer and less about the rebel alliance’s struggle, have a look at Angewandte Chemie.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Fried eggs, frying pans and fluoropolymers

Chemistry World blog (RSC) - 16 September, 2014 - 15:57

Guest post by Jen Dougan

Of all the components of a cooked breakfast, a perfectly fried egg is arguably the most important. It’s for that reason, despite the myriad of other factors to consider – size/weight/colour/celebrity chef endorsement – that a frying pan’s non-stick credentials are key.

Polytetrafluoroethylene (PTFE), the ‘big daddy’ of non-stick, was discovered by accident in 1938. While attempting to make a new CFC refrigerant, American industrial research chemist Roy J. Plunkett noticed that a cylinder of tetrafluoroethylene had stopped flowing but its weight suggested something still inside. In his own words, ‘more out of curiosity… than anything else,’ Plunkett and his assistant cut open the cylinder to discover it was packed at the bottom and sides with a white, waxy solid. Analysis showed that the material was chemically inert, thermally and electrically resistant, and had very low surface friction.

What they had discovered was PTFE, a linear fluoropolymer prepared by the free-radical polymerisation of tetrafluorethylene. The carbon–fluorine bond is the strongest single bond in organic chemistry and the fluorine substituents shield the carbon skeleton from attack, making it chemically inert. Because of its useful material properties (and far from thoughts of fried eggs) PTFE was branded as Teflon and found uses in the Manhattan project, aerospace industries and even gecko research (it is the only known material to which a gecko’s feet cannot stick). But how did Teflon make its way from nuclear research into our kitchens?

By the 1950s Teflon was being used in fishing lines and a French woman asked her husband, an engineer, to coat her aluminium cooking pans with the material. PTFE-coated non-stick cookware was created, and launched as TefAl (from Teflon Aluminium). By the 1960s PTFE–coated cookware was being used in kitchens on both sides of the Atlantic.

However, on searching recently for a new frying pan I found many instances of implied safety issues with PTFE, mostly from ‘eco pan’ manufacturers and advocates. Two main themes recurred in accusations against PTFE cookware: concerns over perfluorooctanoic acid (PFOA), a surfactant used in its production, and ‘polymer fume fever’ – symptoms caused by inhaling polymer decomposition products.

PFOA is an environmentally persistent chemical and, in the mid-2000s, was classified by the US Environmental Protection Agency (EPA) as ‘likely to be carcinogenic to humans’. DuPont, a major user and producer of PFOA, settled with the EPA in 2005 over its failure to report possible health risks associated with PFOA. While PFOA is not present in PTFE cookware itself (it is destroyed during the manufacturing process), it was an environmental concern and after EPA stewardship, PFOA is no longer manufactured nor used by the major global fluoropolymer manufacturers, including DuPont.

Aside from PFOA concerns, PTFE coatings do begin to degrade at 260 °C. The decomposition of the polymer coating produces fumes, which, if inhaled, can cause ‘polymer fume fever’ – temporary symptoms much like the flu virus (see Shusterman DJ, Occup Med. 1993 8(3) 519). But just how likely is this to occur? It is possible to rapidly heat a pan to >260 °C, but if you follow the manufacturer’s instructions and don’t heat an empty pan,you would likely avoid any instances. The most common fats used in cooking have a smoke point well below 260 °C, which should act as a sufficient indicator of pan temperature and kitchen safety. Obviously, heating the pan without fat as a temperature gauge is riskier and should be avoided.

Still not keen on PTFE? There are alternatives. Used for cookware since the Han Dynasty in China (206 BC – AD 260) and still popular with cooks today, cast iron pans have unquestionably stood the test of time. Cast iron frying pans come bare or with an enamelled coating. Bare cast iron pans are porous and to achieve a non-stick finish worthy of a fried egg, oil is polymerised to form a hydrophobic layer across the pan surface. This process, known as ‘seasoning,’ can be repeated as required (depending on treatment of the pan), though is usually recommended yearly.

I’m satisfied that with normal use, PTFE pans will produce perfectly fried eggs without adverse health effects (apart from a risk of increased cholesterol). The only remaining question is whether to have them over-easy or sunny side up?

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.