Author: David Bradley

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

Benzene in the London Times

Benzene RingUK paper the Times today picked up on the benzene in soft drinks problem I mentioned in sciencebase on February 22.

The paper reports how the Food Standards Agency has found levels of benzene (“six parts carbon, six parts hydrogen”) at eight times the level permitted in drinking water in samples from some 230 drinks on sale in Britain and France.

What’s more interesting than this finding, eight times a miniscule amount remains a miniscule amount, is that the paper lists several sources of benzene to which we might be exposed. It is, says reporter Rajeev Syal, It is produced during incomplete combustion of carbon-rich substances: “produced from petrochemicals, but occurs naturally in volcanoes, forest fires and in cigarette smoke. Volcanologists, forestry firefighters, and smokers should be listed among those banned from worrying about their being too much benzene in their cola, bottled water, or ‘fruit’ drink.

Regardless of the actual hazards involved, what’s the betting that benzene in soft drinks will displace fears of bird flu, in the UK, for at least a couple of weeks. It might just be long enough to keep the media fed until all those ducks have flown the coop, as it were…

You can read The Times’ article (here).

Spectral Lines

The latest news round-up science news at spectroscopyNOW from David Bradley is now available online. Read about how Crystallography finds missing piece of haem puzzle, Computing enzymes, The inside story of rocks and fossils, Portable IR lays David’s surface bare, Swell idea for medicine, Electronic speed camera; all the latest spectroscopy news and more.

While you’re there you can grab a free subscription to spectroscopy magazine too.

Scurrying Salamanders

TL:DR – Short news article from 2006 about salamanders. The headline alludes to a lyric from a song by the band Genesis, The Carpet Crawlers.

Salamanders can transform from an aquatic juvenile form into their terrestrial, adult form only if the stream bed on which they develop is of the right nature. A study published today in the journal BMC Biology reveals that the Oklahoma salamander Eurycea tynerensis metamorphoses into a terrestrial adult form in streambeds composed of fine, tightly packed gravel but stays in the juvenile form in loosely packed streambeds composed of large particles.

The study by Ronald Bonett and Paul Chippindale from the University of Texas at Arlington, Texas, USA, exemplifies how small habitat differences can influence developmental patterns and morphology, they also suggest that such microstructure changes could influence a species’ evolution too.

Bonett and Chippindale explain that large gravel creates porous streambeds with large spaces between particles, where aquatic paedomorphic salamanders can access sub-surface water during dry months. However, if these spaces are filled in by small particles, metamorphosis is the only way they can survive when surface streams dry-up.

The Inner Secrets of Rocks and Fossils

Researchers at UCLA have produced the first 3D images of fossils embedded in rocks aged between 650 and 850 million years old. New microscopy and spectroscopy techniques allowed them to sneak an interior peek inside ancient rocks without having to crack them open. The research allows them to spot signs of ancient microscopic life, such as fossil cell walls and could be useful in studying extraterrestrial rocks in the search for alien life.

Dig inside the full story in David Bradley’s news page on spectroscopynow.com

Electronic Speed-trap

A speed-trap for electrons joyriding through single crystals based on MRI can reveal their velocities and produce an image showing an electron density map of the electrons in the crystal. In a kind of cold-case re-opened, the technique provides new evidence to show that the electrons are not breaking Ohm’s law.

Noam Kaplan of the Hebrew University in Jerusalem and colleagues M Drescher and E Dormann at Karlsruhe University, Germany, have developed a technique to measure electron velocity, separate from the electric current flowing through the material. Current is analogous to measuring the number of cars that pass a speed trap rather than the velocity of individual vehicles. The team used MRI, not to produce an image, but to detect electrons simply by monitoring their spin. To measure electron velocity, however, they scanned the crystal, a radical cation salt, with no current flowing.

You can find out what their experiments revealed in David Bradley’s latest news round-up on spectroscopynow.com

The Alchemist Born Again

For those of you who didn’t know, ChemWeb’s “The Alchemist” was given a new lease of life by chemical searching company Chemindustry.com some time ago now. In fact, I’ve just compiled issue 38 of the “new” chemistry news round-up. It’s live today and covers a diverse range of chemical matter including an expose on how soil-eating microbes can be engineered to produce biodegradable plastics, more revelations on benzene in soft drinks, and the scandal surrounding the US’s refusal to grant eminent Indian chemist Goverdhan Mehta an entry visa

Read on…

Regulatory Compliance

Did you know that all US firms have to keep all records, including e-mails and other electronic records for at least five years under the Sarbanes-Oxley Act of 2002? Moreover, if your company is in healthcare, then you also have to hang on to a variety of emails and documents, such as contracts, policy and procedure documents, patient communications, authorizations and consumer complaints for six years! You can find out more and how to manage your email and IM (instant messaging) files in this White Paper

Mormon Crickets Go Cannibal

Mormon Cricket - CannibalismHunger for protein and salt, and a fear of cannibalism, drives the
mass migration of Mormon crickets across western North America, says Stephen Simpson of the University of Sydney, Australia. Mormon cricket swarms, sometimes millions strong covering more than 50 miles in a season. They destroy vegetation in their path and are a severe hazard to drivers.

Locust plagues of Biblical proportions have been with mankind, since, well, Biblical times, at least(!) and usually these creatures swarm in response to a shortage of food. The precise nutritional triggers for the migrations of Mormon crickets though have remained a mystery. Now, field observations by Simpson and his colleagues offer an explanation.

It seems that total starvation is not the driving force, rather migratory crickets preferentially feed at experimental protein-rich and salt rich sources. In the field, crickets were frequently observed feeding on carrion and on each other. When the movement of crickets was experimentally impaired (immobilized by gluing and/or tethering), these insects became targets for cannibalism by neighbouring crickets. These results thus reveal a different model for collective motion, with the crickets’ migration in effect a forced march, the researchers say. The constant threat of cannibalism from the rear appears to push the crickets’ movement as much as the need to find protein and salt pulls it.

Simpson and his colleagues publish further details of their findings today in the online edition of PNAS.