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Study reveals low density water structure in a cryoprotectant matrix

29 April 2016

Scientists from the School of Physics and Astronomy have determined the impact of cryoprotectant molecules on water, and gained access to the structure of water at temperatures far below zero degrees Celsius. The study was highlighted on the cover of The Journal of Physical Chemistry B, with cover art designed by Leeds Physics undergraduate Jamie Ridley.

 

Leeds physicists Dr Lorna Dougan and Dr James Towey showed that when the cryoprotectant molecule glycerol was mixed with water, the molecules nanosegregated into a mesh or 'or sponge' that locked small clusters of water molecules into pockets. They then cooled the mixture down to 238 K and found that these water clusters persisted. In normal freezing, water molecules link up to form ice crystals, however in the cryoprotectant mesh the water molecules remained liquid.  The study revealed that in this matrix the water forms a low density structure which is protected by an extensive and encapsulating glycerol interface.

The paper can be found here: http://pubs.acs.org/doi/abs/10.1021/acs.jpcb.6b01185


The study was supported by the Engineering Physical Sciences Research Council, through a PhD studentship to Dr James Towey, and the European Research Council, through a fellowship to Dr Lorna Dougan.




International Women's Day in Physics

14 March 2016

International Women’s Day recently took place across the world; a day to recognise women and their achievements in all fields. In Physics and Astronomy we celebrated by hosting an informal afternoon tea session, fuelled by discussions around Women in Science and each person’s journey to where they are now and how gender has impacted that

Professor Julia Yeomans FRS from the University of Oxford was our guest for the session and spoke about her experiences throughout her career, it generated some fascinating discussions and was a great opportunity for all women in the school, ranging from academics to administrators to look at how gender has impacted their career, both positively and negatively.

In addition to this, Professor Yeomans was also the speaker at the Stoner Colloquium, where she discussed ‘Nature’s Engines; Powering Life’, an inspiring talk about active matter.

Information about Stoner Colloquia is here.




Stoner Colloquium

3 December 2015

Dr Paul Collier, Head of Beams at CERN was the School of Physics and Astronomy’s invited speaker to give a Stoner Colloquium.

Paul’s background is in Applied Physics and Electrical Engineering, he studied his Undergraduate degree here at University of Leeds and has since studied and worked at Sheffield Hallam, so it was good to be able to welcome him back to Leeds.

Dr Collier spoke about ‘The LHC: Past, Present and Future’, and received a fantastic turnout from across the University and elsewhere.

Dr Collier also gave an alumni talk the following day to a variety of undergraduates, postgraduates and postdocs and highlight the relevant opportunities at CERN.

The next Stoner Colloquium will be on Tuesday 8th March 2016 and our invited speaker is Professor Julia Yeomans from University of Oxford.




Supercoiled DNA is far more dynamic than the “Watson-Crick” double helix

15 October 2015

Researchers have imaged in unprecedented detail the three-dimensional structure of supercoiled DNA, revealing that its shape is much more dynamic than the well-known double helix.

Various DNA shapes, including figure-8s, were imaged using a powerful microscopy technique by researchers at the Baylor College of Medicine in the US, and then examined using supercomputer simulations run at the University of Leeds.

As reported online in the journal Nature Communications, the simulations also show the dynamic nature of DNA, which constantly wiggles and morphs into different shapes – a far cry from the commonly held idea of a rigid and static double helix structure. Dr Sarah Harris from the School of Physics and Astronomy led the computer simulation research side of the study and explained that this is because the action of drug molecules relies on them recognising a specific molecular shape – much like a key fits a particular lock.

The double helix shape has a firm place in the public's collective consciousness. It is referenced in popular culture and often features in art and design. But the shape of DNA isn’t always that simple.
Dr Harris said, “When Watson and Crick described the DNA double helix, they were looking at a tiny part of a real genome, only about one turn of the double helix. This is about 12 DNA ‘base pairs’, which are the building blocks of DNA that form the rungs of the helical ladder.

“Our study looks at DNA on a somewhat grander scale – several hundreds of base pairs – and even this relatively modest increase in size reveals a whole new richness in the behaviour of the DNA molecule.”

There are actually about 3 billion base pairs that make up the complete set of DNA instructions in humans. This is about a metre of DNA. This enormous string of molecular information has to be precisely organised by coiling it up tightly so that it can be squeezed into the nucleus of cells.
To study the structure of DNA when it is crammed into cells, the researchers needed to replicate this coiling of DNA.

Improving our understanding of what DNA looks like when it is in the cell will help us to design better medicines, such as new antibiotics or more effective cancer chemotherapies.

See the full story…




Prof Gleeson gives Inaugural Lecture

12 October 2015

Prof Helen Gleeson OBE, Cavendish Chair and Head of School elect gave her Inaugural Lecture on 7 October, 2015, entitled 'Looking through the Liquid Crystal Ball'.

Helen was appointed as Cavendish Professor of Physics at the beginning of 2015, becoming the first woman to hold the position, and will take over as Head of the School of Physics and Astronomy in September 2016

Helen heads up the Soft Matter Physics research group at Leeds and the focus of her lecture was her work on liquid crystals.

'We are all familiar with the concept of materials as solids, liquids or gases. Another state of matter, the liquid crystal phase, discovered well over 100 years ago, is responsible for revolutionising our lives in recent years. Liquid crystal devices (LCDs) have allowed the development of mobile technology and have fundamentally changed society. It’s now hard to imagine life without LCDs.”

In her talk Helen described some of the unique features of liquid crystals, explaining how the combination of order, fluidity and functionality is used in technology and by nature, and went on to provide an insight into the future by ‘looking through a liquid crystal ball’! This covered some of the new liquid crystal phases with nanostructures that offer completely new electro-optical phenomena and Helen speculated on some of the emerging non-display applications of liquid crystals, showing that understanding the physics of liquid crystals is both intellectually stimulating and could offer new practical solutions for the future.

You can see Helen’s full lecture presentation here…




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