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Chemistry World

 

News in Brief



A carbon rich exoplanet orbiting a star 1200 light years away from Earth has been found by a team of astronomers. The hot planet, WASP-12b, has a carbon-oxygen ratio much higher than that seen in planets within our Solar System, indicating it could have an interior abundant with diamonds.

 

Carbon rich planet

Artist concept of the extremely hot exoplanet WASP-12b and the host star

© NASA

WASP-12b is 40 times closer to the star it orbits than Earth is to the Sun, making it one of the hottest known exoplanets, with a surface temperature exceeding 2200C. The team, led by Nikku Madhusudhan at Massachusetts Institute of Technology, Cambridge in the US, analysed the infrared spectrum emitted from the planet's atmosphere using Nasa's Spitzer Telescope and compared the absorption features caused by carbon rich molecules with those caused by water. 

Published in Nature (DOI: 10.1038/nature09602), the data suggest the planet's atmosphere has a carbon-oxygen ratio of at least one - indicating a carbide interior rather than silicate (like the Earth) that is abundant in carbon monoxide and has considerably more methane and less water than was expected. 

 

Water and sunlight: a winning catalytic combination

Researchers have incorporated a sunlight-activated trigger into an oxygenation process that uses water as the oxygen source. The combination approach is a step towards mimicking Nature's photocatalytic processes and could lead to a reduction of CO2 emissions and further applications for solar energy.  

Current industrial oxygenation processes are energy consuming, resulting in large amounts of CO2 emissions. The research published in Nature Chemistry  (DOI: 10.1038/nchem.905) by a team from Japan and Korea uses a ruthenium(II) complex to absorb sunlight energy that it uses to reduce a cobalt complex. The resulting ruthenium(III) complex reacts with a porphyrin oxygenation catalyst that gives off a proton to become the active species responsible for the oxidation of organic substrates, using water as the oxygen source. 

 

Enzyme holds promise as obesity target 

Blocking a key gut enzyme involved in hunger response can reduce weight gain in mice, say researchers. The approach could eventually lead to treatments for obesity in humans by damping down hunger pangs. 

Ghrelin, also known as 'the hunger hormone', is normally activated by the enzyme ghrelin O-acyltransferase (Goat), which attaches an eight-carbon fatty acid to one of the hormone's serine residues to produce acyl-ghrelin. Without Goat, ghrelin can't trigger hunger. The US and Taiwanese team who carried out the research designed a molecule to block Goat (GO-CoA-Tat) containing ghrelin residues and octanyl-CoA that reduced weight gain in normal mice, but not in mice that were deficient in the hunger hormone, suggesting the effect was due to a lack of activated ghrelin.  

The research is published in Science  (DOI: 10.1126/science.1196154). 

 

Climate deal back on track

The United Nations (UN) climate change summit in Cancun, Mexico has reached a global climate deal that includes a fund to help developing countries access low carbon technologies in order to meet their emission targets. 

The deal also includes agreements on: peak carbon dioxide emissions and an overall target to limit temperature rise to two degrees; that all countries must disclose the measures they employ to tackle climate change; that a system to monitor each country's progress to take action on emissions is set up; and that deforestation should be slowed. 

However, the draft deal, whilst saying more drastic cuts in carbon dioxide emissions are needed, does not establish a mechanism for achieving the targets each country has pledged to reach. It is hoped that these details will come in time. 

In a statement, the UK Prime Minister David Cameron said: 'The Cancun agreement is a very significant step forward in renewing the determination of the international community to tackle climate change.'

 

Grant proposal control

The Engineering and Physical Sciences Research Council (EPSRC) has recorded a four per cent rise in successful grant proposals this year, up from 26 per cent last year to 30 per cent. 

Research Councils in the UK have been under pressure to introduce measures that control the demand of grant applications for research in an effort to improve service. The EPSRC has introduced 'demand-management' measures, which include a ban on the resubmission of proposals that were not officially invited and temporary restrictions on repeatedly submitting unsuccessful applications. 

The measures have led to an increase in the number of grant applications being approved by the EPSRC, but have also led to a 35 per cent drop in applications overall.  

In contrast, other Research Councils such as the Medical Research Council have seen grant application success rates fall. Therefore, 'demand management' could be the answer for other UK Research Councils. 

 

Chemical water bottle

A carbon cage that can hold a single water molecule inside using a stopper, could be the smallest water bottle ever, say researchers.

Carbon spheres known as fullerenes have cavities large enough to encapsulate atoms or molecules inside and have many potential applications. In research published in Angewandte Chemie International Edition (DOI: 10.1002/anie.201004879), a team of German and Chinese chemists designed a molecular vial by opening an intact fullerene cage. They then finished off the water bottle with a stopper - a reversibly bound phosphate group - that can plug the opening or be removed to allow a molecule of water in and out. 

The molecular vial can be opened or closed in one easy step and could be used as a molecular transporter or carrier in future. 

 

Novel green separation system

Researchers in Canada have developed a new chromatographic separation method that could make an inexpensive and green contribution to the analytical chemist's toolbox.

The team at the University of Calgary were experimenting with water saturated with CO at high temperature and pressure as a mobile phase in a chromatography system. They used a conventional packed column as the stationary phase and stainless steel tubing either side of the column. When the experiment was finished they removed the column and flushed the remaining sample through. To their surprise, they realised that separation was still occurring. Further investigation revealed that water was coating the inner surface of the tubing and remaining stationary. 

 

Novel green separation system

The team analysed the caffeine content of a cup of coffee

To demonstrate the utility of the system, the team analysed the caffeine content of a cup of coffee. Because of the high differential solubility of caffeine between the phases, sharp peaks were observed with no sample preparation needed. 

The new technique published in Analytical Chemistry  (DOI: 10.1021/ac1018793) is green - it does not use organic solvents or an organic stationary phase - and is inexpensive. 

 

Imaging atomic control

Researchers in the Netherlands, US and UK have imaged for the first time an atomic angular momentum vector precessing in a magnetic field.  

Precession arises because angular momentum vectors, like nuclear spins, have an associated magnetic moment that can be made to align with a magnetic field. The team employed velocity map imaging - a technique widely used to study gas-phase photochemical reactions - to image molecular oxygen dissociated by a UV laser.  

The resulting oxygen atoms possess highly aligned orbital angular momenta, which the team then caused to precess by applying a magnetic field. They then ionised the atoms with a second polarised laser and used an electric field to accelerate the ions towards a detector that maps their positions in three dimensions.  

The research is published in Nature Chemistry  (DOI: 10.1038/nchem.929). 

 

Scientific advice not needed

New legislation that allows the UK government to change the law on controlled substances without consulting scientific experts has been published. 

At present the Advisory Council on the Misuse of Drugs (ACMD) - the UK government's drugs advisory panel - must include six doctors and scientists. But now the Police Reform and Social Responsibility Bill will abolish this legal requirement by removing clauses from the 1971 Misuse of Drugs Act, and will also allow the Home Secretary, Theresa May, to make substances illegal for up to a year without seeking advice. 

This move comes almost a year after six members of the ACMD resigned (see  Chemistry World, March 2010, p5) after the last Home Secretary Alan Johnson sacked David Nutt, the ACMD chair for questioning government decisions on drug classification. 

Also of interest

Water and sunlight

Water and sunlight: a winning catalytic combination

28 November 2010

Researchers have incorporated a sunlight-activated trigger into an oxygenation process that uses water as the oxygen source


Obese mouse

'Hunger hormone' activating enzyme holds promise as obesity target

18 November 2010

Blocking ghrelin activation with an experimental drug prevents weight gain in mice


Chromatography using water and carbon dioxide

Novel green separation system

23 November 2010

Canadian chemists serendipitously discover a new chromatography separation system that uses only carbon dioxide and water


Precession

Images show atom 'spinning top' control

12 December 2010

Precession of quantum mechanical angular momentum in atomic oxygen can be directed and pictured, potentially allowing more detailed reaction studies