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Building a nation of scientists

13 Feb 2012

Goverdhan Mehta talks to Sheena Elliott and Elinor Richards about the progress of science in India and the challenges scientists face

Goverdhan Mehta is a researcher, specialising in organic synthesis. He has helped to build institutions in India – the Indian Institute of Technology, Kanpur, the University of Hyderabad, and the Indian Institute of Science, Bangalore. He was director of the Indian Institute of Science (1998-2005) and vice chancellor of the University of Hyderabad (1994-1998).

Read the interview in Chemistry World

Link to Journal Article

Towards a temperature-guided molecular switch: an unusual reversible low-temperature polymorphic phase transition in a conformationally locked environment
Goverdhan Mehta and Saikat Sen
Chem. Commun., 2009, 5981-5983
DOI: 10.1039/B905651C

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Instant ecstasy detector

10 Feb 2012

An on the spot detector for ecstasy tablets has been made by scientists in Spain. The probe has been designed to detect the active ingredient in ecstasy – MDMA (3,4-methylenedioxymethamphetamine) – even when it is mixed with other common additives, which has been a challenge.

One way to detect ecstasy is a colorimetric test, but the test is not specific for MDMA and is unable to distinguish it from amphetamine and other common phenethylamines. Another method is chromatography, which can distinguish between these compounds but isn’t portable. Now, Tomás Torroba and his team from the University of Burgos have made a fluorimetric compound that can be used to identify MDMA. ‘The fluorogenic probe may be used as an in situ test for fast detection. It only needs a small sample and can be checked with a portable ultraviolet lamp,’ says Torroba.

The probe – a diaryl urea tagged with two fluorescent indicator units – is selective for primary and secondary amines, so it can only reveal that a primary or secondary amine is present. ‘It would be difficult to distinguish the difference between amphetamine or MDMA by the naked eye,’ says Torroba. ‘A mathematical trick is required.’

The fluorogenic probe (structure shown) was developed to detect MDMA from ecstasy tablets, even when it's mixed with other common additives such as sucrose, chalk and caffeine, showing a green fluorescent emission at 517nm

Read the full story in Chemistry World

Link to Journal Article
A turn-on fluorogenic probe for detection of MDMA from ecstasy tablets
Daniel Moreno , Borja Díaz de Greñu , Begoña García , Saturnino Ibeas and Tomás Torroba
Chem. Commun., 2012, Advance Article
DOI: 10.1039/C2CC17823K

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Mineral regulates early metabolism

16 Jan 2012

Chinese scientists have taken a step towards further understanding the reactions that led to the origin of life by showing that a crucial metabolic process can be photocatalysed on the surface of a common mineral.

The citric acid or tricarboxylic acid cycle is central to almost all life and is used to generate energy from the conversion of acetate from fats, proteins and carbohydrates to carbon dioxide and water. Some bacteria run this cycle in reverse in a reductive tricarboxylic acid cycle (rTCA), making carbon compounds from carbon dioxide and water, and this has been suggested to be the central part of primordial metabolism.

Wei Wang from Harbin Institute of Technology and colleagues claim that early reactions to form biological molecules and metabolic pathways could have occurred on the surface of sulfide minerals in under-sea hydrothermal vents. This could explain why enzymes containing transition metal-sulfide clusters play a vital role in the metabolism of most organisms.

Early metabolic reactions could have happened on the surface of the mineral sphalerite (ZnS)

Read the full article in Chemistry World

Link to Article
Photocatalytic reversible amination of α-keto acids on a ZnS surface: implications for the prebiotic metabolism
Wei Wang, Qiliang Li, Bin Yang, Xiaoyang Liu, Yanqiang Yang and Wenhui Su
Chem. Commun., 2012, Advance Article
DOI: 10.1039/C2CC15665B

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Catalyst clears up corrosion

12 Dec 2011

UK scientists have developed a cheap way of cleaning tarnished metals in industry to prevent corrosion using a UV activated photocatalyst ink. The dirty surface can then simply be washed away with water.

Stainless steel corrosion in industry costs the UK around 4 per cent of gross national product each year. The corrosion is caused by a build up of metal oxides on the metals’ surfaces, which can become contaminated with corrosion products. Currently, aggressive chemicals such as strong acids and chelating agents are used to remove the oxides.

Andrew Mills and David Hazafy from Queen’s University, Belfast, have made anatase titania (TiO₂) films to apply to the metal surfaces to clean them. The team was initially interested in titania’s ability to drive ‘useful photo-reduction reactions’, says Mills. It was while preparing TiO₂ photocatalyst films on stainless steel as part of a water-splitting photo diode project that they noticed that the appearance of tarnish was diminished.

TiO₂ is a well known photocatalyst used in the redox reductions of metal oxides. When it is exposed to ultraviolet light, conduction band electrons and valence band holes are produced. The electrons and holes can either recombine or move to the surface of the film where they undergo redox reactions with adsorbed chemical species. But, on introduction of an electron donor, such as ethanol, the donor reacts with the holes, leaving the electrons free to react with metal oxides.

A stainless steel sample without (A) and with (B) the ink on its surface. (C): irradiation of sample B with UV light through a brass TiO₂ template. (D): washing off the ink using water. The bronze coloured oxide coating has been removed by the illuminated section of the ink

Read the full story in Chemistry World

Link to journal article
UV-activated photocatalyst films and inks for cleaning tarnished metals
Andrew Mills and David Hazafy
Chem. Commun., 2012, 48, 525-527
DOI: 10.1039/C1CC15774D

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Artificial enzyme outperforms nature

01 Dec 2011

Scientists from China and the US have made an artificial enzyme that may provide new hope for the treatment of Lou Gehrig’s disease (a degenerative neuromuscular disease that destroys nerve cells in the brain and spinal cord). In tests, the apoferritin–CeO₂ nanocomposite cleared harmful reactive oxygen species – which have been linked to the disease – in living cells better than the natural antioxidant enzyme superoxide dismutase.

Reference:
Apoferritin-CeO₂ nano-truffle that has excellent artificial redox enzyme activity
X Liu, W Wei, Q Yuan, X Zhang, N Li, Y Du, G Ma, C Yan and D Ma, Chem. Commun., 2011
DOI: 10.1039/c1cc15815e

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Catalyst to wash tarnished metals in industry

24 Nov 2011

A simple and cheap way to clean tarnished metals using a UV activated photocatalyst ink has been developed by UK scientists. Removing steel corrosion is a major concern in many industries. Most metals are thermodynamically unstable in air and aqueous solution but owe their durability to metal oxides that form on the surface. However, when the metal oxides thicken, it leads to contamination with undesirable corrosion products that need to be removed. Aggressive chemicals such as strong acids and chelating agents are usually required to remove them.

The photocatalyst ink was applied to the tarnished metal and then UV light was shone onto it. This produced conduction band electrons and valence band holes. An electron donor species in the ink reacted with the holes, leaving the photogenerated electrons to react with absorbed metal ions. The metal oxide layer could then be removed with water.

: Photographs of an annealed stainless steel coupon without (A) and with (B) a rectangle of the inks cast on its surface. UVA irradiation of sample B through a brass ‘TiO2’ template (C) revealed an image of the ‘TiO2’ template on the coupon, (D)

Reference:
Photocatalyst film and ink for cleaning tarnished metals
A Mills and D Hazafy, Chem. Commun., 2011
DOI: 10.1039/c1cc15774d

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Author Archive

Building a nation of scientists

Instant ecstasy detector

Mineral regulates early metabolism

Catalyst clears up corrosion

Artificial enzyme outperforms nature

Catalyst to wash tarnished metals in industry

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