David Bradley – Page 351

Ionic Liquids Lose their Green Stripes

Despite being heralded as the green alternative to noxious, toxic, inflammable volatile organic compounds, room temperature ionic liquids are slowly losing their green stripes. In a paper published in the journal Green Chemistry (2006, 8, 238-240), Italian researchers report the acute toxicity of these compounds to zebra fish.

Luigi Intorre of the University of Pisa and colleagues, explain that although interest in ionic liquids because of claimed environmental safety is on the increase, these very good non-volatile solvents, could have harmful effects on certain ecosystems nevertheless.

The team has assessed the acute toxicity towards zebrafish of several ionic liquids with different anions and cations and found that toxic effects depended on the specific structure of the ionic liquid. However, the overall effect is potentially fatal harm to the fish’s gills.

This publication comes in the wake of earlier revelations that ionic liquids, although purportedly non-volatile, can indeed be distilled, according to a C&EN report.

Having said all that, ionic liquids still present a potentially “greener” alternative, if handled and disposed of safely, than many of the volatile organic solvents used in industry.

Pretti, C., Chiappe, C., Pieraccini, D., Gregori, M., Abramo, F., Monni, G., & Intorre, L. (2006). Acute toxicity of ionic liquids to the zebrafish (Danio rerio) Green Chemistry, 8 (3) DOI: 10.1039/b511554j

Black Eyed Peas – Big Hit in Nanotech

Researchers at the John Innes Centre in Norwich have grown particles of a mosaic virus that infects black-eyed peas and dressed them up with a redox-active organometallic compound* to convert the particles into nanoscopic molecular capacitors.

The virus, which is only harmful to black-eyed, or cowpea plants, has a unique structure making it the perfect scaffold for chemical modification, allowing the team to tailor its chemical and physical properties to particular applications.

‘This is an exciting discovery in bionanotechnology using plant viruses to produce electronically active nanoparticles of defined size’ says graduate student Nicole Steinmetz, who is working on the EU-funded project with project leader David Evans and George Lomonossoff of the Department of Biological Chemistry. ‘Future applications may be in, for example, biosensors, nanoelectronic devices, and electrocatalytic processes,’ she adds.

The project is still in the very early stages, by the JIC considered it newsworthy enough to publish a press release today and capitalise on the popularity of young people’s popular music beat combo the Black-eyed Peas, and never one to miss out on an opportunity for catching a few new readers, particularly among the youth of today, Sciencebase is getting down with it, to give it a mention too.

The work was published in detail in the journal ‘Small’ and is, the press release says, the first piece of nanotechnology from the John Innes Centre.

Meanwhile, if you want more on the business of nanotech, you might wish to subscribe to Small Times, which you can get for free for a year through this special Sciencebase link. Grab it while you can, as these magazines sometimes drop off the roster.

*240 units of a ferrocenecarboxylate, in fact.

The Chemical Name Game

Working chemists would much prefer to be left to their own devices to come up with names for the compounds they discover. Names that trip off the tongue, names that twist it. Names that honour colleagues, the famous, home towns and occasionally slime moulds are all much nicer than sticking to the rules. So what’s in a name? as the man asked, and why shouldn’t we keep it trivial?

Read my cynical take on all that is systematic and all that is trivial in the world of chemical nomenclature

Avian Influenza Lottery

According to a previous interviewee of mine, Sir David King (one-time UK chief advisor on science), you’ve got far more chance of winning the lottery than catching H5N1, the most-talked about of the avian influenza viruses. King told The Times that the chances of someone in Britain catching bird flu is 1 in 100 million. Compare that with the 14 million to one chance of winning the lottery and you can see just how small the risk is.

It’s essentially what we’ve been saying all along, the media generally loves a health scare, and H5N1 is just the latest of those (along with benzene in soft drinks of course). It is nevertheless only a matter of time before someone in the UK does succumb to this virus (unlocky sod), but even when they do, that does not herald the global pandemic of killer flu that the scaremongers are hoping for. I say hoping, they really will have a field day once that little bundle of genetic material and protein finds a way to carry itself from human to human…good news never sold papers, after all.

Pro Active Health and Diet

Catching up with the Sunday supplements two ads caught my eye. The first was for Flora pro.activ, which contains dairy peptides and supposedly is proven to help control blood pressure and maintain a healthy heart. The second was for Sirco, which is apparently approved by Heart UK and is supposed to “naturall” thin the blood to help improve its flow. On the same day, I read a BBC news item telling us that eating oily fish isn’t as good for us as we had been led to believe. Also in the mail that day was a reprint from by friend Bradford Frank (an MD at the University of Buffalo School of Medicine), his paper [Ann Clin Psyc, 2005, 17(4), 269-286] reviewed the various antioxidants and stacked up the evidence for which are any good at reducing the risk of developing Alzheimer’s disease. Seemingly, aged garlic extract, curcumin, melatonin, resveratrol, Gingko biloba extract, green tea, and vitamins C & E all have a strong association with a reduced risk of AD. On the other hand, acetyl-L-carnitine, alpha-lipoic acid, bacopa monniera, ferulic acid, and ginseng are only very weakly associated with any reduction in risk. Huperzine A, adds Frank, falls into a special category as this compound actually inhibits the very enzyme that AD drugs target – acetylcholinesterase (AChE).

So, what is one to make of all these various pieces of information. It seems to me that far too much effort is spent on trying to augment the healthy balanced diet we should all aspire to, but more importantly, all these various threads seem to suggest that exercise and mental activity play no role in protecting us from disease. The people who buy pro-activ and Sirco, and those who pop dozens of different antioxidants, trace elements, and vitamins might hope to live forever, but with the impending threat of emerging viral disease and nuclear terrorists, a splash of Sirco or a handful of Gingko leaves is probably not going to help.

Missing Bio Link

The missing piece in the biochemistry of haem (heme) is reported in this week’s spectroscopyNOW. Japanese researchers have used x-ray diffraction to determine the crystal structure of the enzyme human indoleamine 2,3-dioxygenase (IDO). This crucial enzyme splits the pyrrole ring of the amino acid L-tryptophan and incorporates both atoms of a molecule of oxygen, an essential step in dozens of metabolic reactions. The discovery could have implications for other studies involving this enzyme and medical problems with which it is associated.

Swell Gels

In my latest news round-up on spectroscopynow, we report on new materials based on cross-linking polymers have been shown to swell and contract in a controlled way depending on temperature an pH. The researchers used various analytical techniques to track the syntheses of these materials and their behaviour, including proton NMR, XPS (X-ray photoemission spectroscopy), and Fourier transform infrared spectroscopy.

Such smart gels may have applications in tissue engineering and drug delivery.

A Logical View of Enzymes

David Bradley reports in this week’s SpectroscopyNow on how scientists in Israel are using UV-Vis spectroscopy to track the underlying logic of enzyme systems that compute.

The research could lead ultimately to implantable enzyme-based computers that respond to metabolic changes in the body and allow complex drug therapies to be monitored and controlled.

Benzene Soda Sense

Sciencebase has just received some additional information from Sense About Sense on the benzene in soft drinks debacle. SAS, is a UK organisation that promotes an evidence-based approach to scientific issues (something that all organisation should be promoting to be honest!).

Anyway, according to their spokesman (Cambridge chemist Jonathan Goodman), one would have to drink almost a litre (800 ml) of soft drink containing five times the WHO limit to match exposure from a single car journey. This is a comparison to that made by Richard Laming of the BSDA who says that someone living in a city consumes, on average, 400 micrograms of benzene from exhaust fumes in a normal day, which is equivalent to consuming 40 litres of a soft drink containing benzene at just over the World Health Organization guideline level of 10 parts per billion.

SAS also told us that benzoate does indeed degrade to benzene, as other media reports claimed. However, either of the possible reaction pathways, while plausible, “are probably very slow.”

Speedy Molecular Movements

High-speed observations of hydrogen ions (protons) moving within a molecule could allow chemists to gain new insights into the fundamental processes that take place in reactions, according to UK scientists writing in the journal Science today.

John Tisch of Imperial College London and his colleagues have captured proton movements on the attosecond scale. (Check out our atto to yocto page for a definition). The research provides new clues as to how molecules behave in chemical and biological processes.

“Slicing up a second into intervals as miniscule as 100 attoseconds, as our new technique enables us to do, is extremely hard to conceptualise,” says Tisch, “It’s like chopping up the 630 million kilometres from here to Jupiter into pieces as wide as a human hair.”

Jon Marangos, Director of the Blackett Laboratory Laser Consortium at Imperial, adds that the new technique means scientists will now be able to measure and control the ultra-fast dynamics of molecules. “Control of this kind underpins an array of future technologies, such as control of chemical reactions, quantum computing and high brightness x-ray light sources for material processing. We now have a much clearer insight into what is happening within molecules and this allows us to carry out more stringent testing of theories of molecular structure and motion. This is likely to lead to improved methods of molecular synthesis and the nano-fabrication of a new generation of materials,” explains Marangos.

To make the breakthrough, the scientists, include lead author Sarah Baker, used a specially built laser system capable of producing extremely brief bursts of light. This pulsed light has an oscillating electrical field that exerts a powerful force on the electrons surrounding the protons, repeatedly tearing them from the molecule and driving them back into it. This process causes the electrons to carry a large amount of energy, which they release as an x-ray photon before returning to their original state. How bright this x-ray is depends on how far the protons move in the time between the electrons’ removal and return. The further the proton moves, the lower the intensity of the x-ray, allowing the team to measure how far a proton has moved during the electron oscillation period.

You can read more about the research in today’s issue of Science