April 2007



A major row has broken out about whether plants emit methane, a potent greenhouse gas.The startling claim that trees could be responsible for putting millions of tonnes of methane into the atmosphere every year was published last year in the prestigious journal Nature. But that has now been rubbished by rival researchers who report that plants emit virtually no methane whatsoever.

Tom Dueck, of Wageningen University in the Netherlands, says his team’s independent investigations are the first published results to show that plants’ methane emissions are negligible or zero. That means their contribution to the global methane budget, and potentially to climate change, simply isn’t worth worrying about.

But Frank Keppler, now at the Max Planck Institute for Chemistry, in Mainz, Germany – whose team announced in January 2006 they had detected methane exhaled from living plants – is sticking to his guns. ‘I am one hundred per cent confident that plants emit methane’, he told Chemistry World, insisting that as yet unpublished research would confirm his findings once and for all.

Read more here.

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These guys put the B in buckyball: they’re predicting the existence and stability of a boron buckyball, B80 : an elemental cousin for the carbon fullerene series, whose first C60 member was discovered back in 1985.

Boris Yakobson (right) and graduate student Arta Sadrzadeh, from Rice University, Texas, US say B80 looks just like a boron version of the carbon buckyball; except that another boron atom has been placed at the centre of each hexagon for more stability. This essentially makes it a football-shaped collection of triangles; closer to the original geodesic domes of architect Richard Buckminster Fuller, after whom the carbon buckminsterfullerene (buckyball) was named.

The molecule hasn’t yet been synthesised, but by analogy to the fullerenes, Yakobson has gone on to predict the (not quite as stable) structures of a whole new family of hollow boron cages, all the way up to B110.

It took 12 years before the first calculations of the carbon buckyball’s stability saw experimental vindication, so Yakobson’s vision could take some time to be fulfilled. And in case you were wondering, silicon doesn’t work – Yakobson predicts it will collapse in on itself.

Ref: N Gonzalez Szwacki, A Sadrzadeh and B I Yakobson, Phys. Rev. Lett., 2007, 98, 166804

 

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Echoing January’s news that drug giant Pfizer was to sell an unsuccessful obesity drug to fat dogs, rather than fat people (who wouldn’t have stood for the alarming side effects), fellow pharma giant Eli Lilly has re-launched its antidepressant Reconcile (a reformulated form of prozac) in chewable, meat flavoured form on the canine market. Reconcile doesn’t share the alarming side effects of Pfizer’s slimming drug Slentrol, but sales were down and, well, there was a gap in the doggy antidepressant market (up to 17 per cent of US dogs suffer from ‘separation anxiety’, according to a company spokesperson)

And perhaps a touch of botox around those wrinkles, Fido?

And perhaps a touch of botox around those wrinkles, Fido?

Good news or bad news? Certainly controversial news. Animal behaviouralists and dog trainers point out a few obvious alternatives for dog owners (boring stuff like ‘keep your dog company’ and ‘take it for regular walks’ etc… which might sort out the obesity, too) while anxious dog owners who simply haven’t got the time have, apparently, been crying out for just such a solution.

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A new study in PLoS Medicine has raised more questions about the supposed painlessness and peacefulness of lethal injection as a form of execution.

Established in Oklahoma as a more humane alternative to the electric chair, lethal injection is now carried out as a principal form of execution in 37 US states, the federal government and the US military. But botched injections have brought its inconsistencies under the microscope numerous times (see Chemistry World Feb 2007)

This study by Leonidas Koniaris from the Miami Miller School of Medicine in the US and his colleagues, analysed the medical data from executions released by some US states, as well as published clinical, laboratory and veterinary animal studies.

The standard three drug protocol (the ultra short acting barbiturate thiopental; the neuromuscular blocker pancuronium bromide and the electrolyte potassium chloride) is intended to produce anaesthesia followed by cardiac arrest. Secrecy surrounding executions means that limited medical data is available, but this study presents procedural problems during executions, insufficient anaesthesia and unreliable drug reactions as evidence that this mode of execution is often far from painless. A drug protocol replicated by so many US states may be fundamentally flawed.

The authors point out that techniques of animal euthanasia in the US and Europe are governed by strict regulations. ‘In stark contrast to animal euthanasia, lethal injection for judicial execution was designed and implemented with no clinical or basic research whatsoever,’ they write.

11 states have now suspended the death penalty as flaws in the lethal injection protocol emerge. Perhaps it is time, as Koniaris suggests, to break the secrecy around lethal injection and engage in an open debate.

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Readers of Chemistry World might remember the fastest synthesis in the west, the impressively speedy total synthesis of platensimycin back in October last year, just four months after its discovery was reported, by KC Nicolaou’s group at the Scripps Research Institute and the University of California, San Diego, US. Well a bunch of other researchers followed KC’s lead – and it would now be an understatement to say this promising antibiotic is well studied by synthetic chemists.

But … the original synthesis (and those that followed) were racemic, so it is possibly worth pointing out that KC has again won the race to the first asymmetric synthesis of platensimycin. In fact he’s got two of them. Well done.

Anyway, if you’d like to follow all the cut and thrust of platensimycin syntheses, everything you could possibly need is explained and discussed at the superb Totally Synthetic

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Scientists have used quantum mechanics to work out why green tea is good for you. The health benefits of the brew are all down to a quirk of the quantum world known as tunneling, they say.

Green tea is traditionally associated with good health and long life – benefits linked to chemicals known as catechins, which act as antioxidants. These polyphenolic flavonoid compounds disrupt the damaging chain reaction between free radicals and lipids.But no one understood how catechins work at micromolar concentrations in the body. Now, Àngels González-Lafont and colleagues at the Autonomous University of Barcelona in Spain have modelled the chemical reaction that allows green tea catechins to zap radicals.

The reaction involves the catechin losing a hydrogen atom to a reactive free radical. The scientists found that in this process the radical and catechin were bound together tightly, leading to very small energy changes as the reaction proceeds.

The compact structures and narrow energy profile revealed by González-Lafont’s calculations allows for a huge tunneling effect in the hydrogen transfer step. This makes the transfer much faster than the free radical’s reaction with the body’s vulnerable lipids, so the radicals are trapped before they can do harm.

Read more here.

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Who is the greatest living chemist? A league table, based on what some argue is the fairest measure of research achievement ever devised, may now provide the answer.

Top of the pile is organic chemist E J Corey of Harvard University, who won the Nobel Prize in Chemistry in 1990 for his ‘masterly development of organic synthesis’ – the ability to stitch together complex carbon-based molecules.

Harvard scientists also occupy slots two and three, in the form of George Whitesides – a pioneer of materials chemistry and nanotechnology – and Martin Karplus, a theoretical chemist. The leading British chemist indexed so far is placed at number 13 – Alan Fersht of Cambridge University, who studies protein chemistry. The full table is published on Chemistry World’s website.

The chemists were ranked by h-index, a number invented by physicist Jorge Hirsch in 2005 to measure research impact. A scientist’s h-index is the highest number of papers they have published which have each amassed at least that number of citations from other authors: Corey, with an h of 132, has published 132 papers which have each received at least 132 citations, for example.

Henry Schaefer, a chemist at the University of Georgia, US, created the rankings with colleague Amy Peterson, and describes it as a work in progress. Though the top 10 won’t surprise anyone, said Schaefer, some Nobel Prize winners are buried deep down in the table. Nobel-winning organometallic chemist E O Fischer, for example, squeezes in at joint 251st with an h of 60. That may be because the Nobel Prize is awarded for one achievement, while the h-index marks a whole career, suggests Schaefer.

Read the full list here.


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The use of ethanol as a gasoline substitute for motor vehicles may not be the environmental panacea that its proponents would have us believe, according to a US atmospheric scientist.

Read more here.

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The world’s smallest pipette has been developed by US scientists. It is capable of dispensing drops of a molten gold-germanium alloy with a volume of a few zeptolitres, that is, a billionth of a trillionth of a litre.

See pictures here.

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The US Food and Drug Administration’s (FDA’s) advisory committee has recommended that the agency does not approve Merck’s latest arthritis drug Arcoxia, a drug in the same class as the company’s withdrawn and now infamous Vioxx.The ruling does not bode well for the future of the much maligned class of cyclooxygenase-2 (Cox-2) selective inhibitor drugs. After Vioxx was shown to increase the risk of cardiovascular complications, the  FDA’s handling of drug safety came under fire. The agency has since ruled that all Cox-2 selective inhibitors carry amended warnings of their side effects.

Read more here.

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