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Atmospheric chemistry work published in Science
7 September 2012
Work from the School of Chemistry has recently been published in Science demonstrating that chemically activated reactions can be important in the lower atmosphere. It is generally assumed that in the atmosphere reactions occur with ground state reagents, but experimental results from PhD student James Lockhart and NCAS Fellow Dr Mark Blitz have shown that the degree of vibrational excitation in the intermediates of the acetylene oxidation process controls the distribution of products between the atmospherically important products of glyoxal and formic acid.
James’ and Mark’s data have been combined by Dr David Glowacki (Univ Bristol) with theory developed at Leeds by Prof Mike Pilling and Dr Struan Robertson and with other calculations from Argonne National Laboratory (Dr Stephen Klippenstein) to elegantly demonstrate how vibrational excitation of the OH-acteylene adduct controls the distribution between possible products. If O2 reacts with the nascent vibrationally excited adduct then the two isomers (which each lead to unique products) are present at ~50:50 and both glyoxal and formic acid products are formed. However if the adducts are relaxed before their subsequent reaction with O2, the distribution of adducts is dominated by the more stable adduct that leads to glyoxal formation.
The Science paper (published Aug 31 2012) explores the potential applications to other oxygen reactions in the atmosphere or in combustion.
The paper can ve viewed at http://www.sciencemag.org/content/337/6098/1066.full?sid=66673f6a-0f83-43de-bd50-2d13bb06c3b8
Nanotoxicology research featured on ACS journal cover
4 September 2012
Nanotoxicology research in Leeds has been featured on the front cover of the American Chemical Society journal Langmuir. The related paper, published inside the journal, is by Dr. Ann Zhang, Prof. Andrew Nelson and Dr. Paul Beales (all from the School of Chemistry). The article explains the impact of the size of silica nanoparticles on their interaction with biological membranes.
Engineered nanoparticles are becoming more commonly used as additives to enhance consumer products, including coatings, foods and cosmetics. They are also being investigated as novel excipients for drug delivery as they show promise to increase therapeutic efficacy, while decreasing unwanted off-target side effects. It has therefore become a high priority to understand how engineered nanoparticles interact with biological systems in order to understand the mechanisms that might lead to toxicity and to optimise their interactions beneficial for intracellular drug delivery. A detailed understanding of how nanoparticle properties relate to their interactions with biological systems, in particular the membrane barriers of cells, will allow industry to develop safe nanomaterials by design. This will be of significant benefit to public health and quality of life as it will facilitate the development of new, safe nanoparticle-enhanced products and medicines.
The work found a highly size-dependent interaction mechanism between silica nanoparticles and DOPC lipid membranes. The smallest particles studied (18 nm) caused the lipids to “freeze” and the resultant condensing of the membrane caused it to fracture, opening a microscale hole. Conversely, larger nanoparticles were shown to disorder the lipids by being wrapped by the membrane in a passive interaction similar to endocytosis in live cells. A theoretical model to explain these observations was developed that considered the competition between nanoparticle adhesion to the membrane and the elastic energy cost for the membrane to bend around the particle. The balance of these two interactions suggested a cross-over in interaction mechanism for these nanoparticles in the size range 28 – 40 nm, consistent with the experimental findings.
The journal cover and full paper is available online at the Langmuir website: http://pubs.acs.org/action/showLargeCover?jcode=langd5&vol=28&issue=35 and http://pubs.acs.org/doi/abs/10.1021/la301771b.
Olympics air monitoring features on the BBC
13 August 2012
Researchers are part of the ClearFlo project which featured on the BBC News.
The ClearFlo project runs for three years. Data is collected from a ground station on a school playground in North Kensington in central London, the top of the BT tower and a research aircraft. The current phase of the project is timed to provide extensive data during the Olympic Games.
Dr. Lisa Whalley (NCAS Fellow), Dr. Daniel Stone (Research Fellow) and Noel Clancy (1st year PhD student), who are members of Professor Dwayne Heard's group, made measurements of short lived radical species that are responsible for the processing and ultimate removal of air pollutants using laser-based instrumentation housed in a purpose-built mobile laboratory.
The BBC item by science editor David Shukman can been seen at http://www.bbc.co.uk/news/science-environment-19180981 and the project's own website is at http://www.clearflo.ac.uk/
New graduates
10 July 2012
Chemistry's class of 2012 received their degrees at a graduation ceremony today.
After the ceremony the School hosted a reception for graduates and their guests and the formal year photograph was taken.
Chemistry team triumphs at Astbury Sports Day
5 July 2012
The 2012 Annual Astbury Lecture was given by Professor Roger Goody of the Max Planck Institute of Molecular Physiology on July 3rd 2012.
Professor Goody’s lecture “Combining structural biology, chemical biology and kinetics to understand Ras-family GTPases” was delivered to a packed Chemistry Lecture theatre A.
The lecture was followed by the traditional Astbury sports day in which Professor Goody narrowly beat Astbury Director Professor Sheena Radford in the egg and spoon race. Nine teams from across the Astbury Centre entered this year’s tournament which involved the obstacle race; relay; medley (sack, wheelbarrow, three-legged and space hopper races); leap-frog; and three team tag rugby.
The winning team was “Brucie’s Bonus” comprising members of the Turnbull and Webb groups. Last year’s winners “The Notorious ASN” (Nelson group) came second with the Astbury executive committee coming third. In a triumphalist speech to accept the trophy, Dr Turnbull inadvertently forgot to thank the Astbury Society for organising a great day, and the other competitors for the high standard of sporting prowess and fair play (Thank you!).
The day concluded with a barbeque in Chancellor’s Court.
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