Features

What do shells, solar panels and DVDs have in common?

At the atomic scale they are ‘amorphous’, that is – unlike crystals – they are built from irregular arrangements of atoms.

As Andrew Goodwin of Oxford University’s Department of Chemistry explains this irregularity is important: it’s what allows shells to grow their curved edges and gives silicon its incredibly useful electronic properties.

But for scientists this irregularity also makes such materials tricky.

‘Our main technique for establishing what materials look like on the atomic scale is crystallography,’ Andrew tells me, ‘and this relies explicitly on the existence of a repeating arrangement of atoms in order to work. So the problem of studying amorphous materials with their seemingly-random arrangements of atoms has remained just that: a problem.’

Now, Andrew, and colleagues from Cambridge and Ohio, report in this week’s Physical Review Letters how tantalising crystallographic clues could offer a new approach to understanding amorphous materials.

‘For decades we’ve known that the ring-like patterns amorphous materials produce in crystallographic experiments contain limited information about the surrounding environment of each atom,’ Andrew comments, ‘but the big question has always been how to use this to create a coherent picture of the structure of a material.’

He explains that the new approach comes from the ‘neighbourly behaviour’ of atoms which means that similar atoms should experience a similar environment.

‘The spacing of the rings in the 'ring-like pattern' is related to the distances between atoms in the material, and the intensity of the rings is essentially related to how many neighbours each atom has,’ Andrew tells me.

‘So, using silicon as an example, a typical analysis of its corresponding crystallographic pattern would have told us that the distance between silicon atoms is about 235 trillionths of a metre [picometres], and that on average each silicon atom has four neighbours.’

Yet this information alone isn’t enough to build reliable models of what the atomic structure of a material such as silicon actually looks like.

Such models fail because they rely on the average ‘neighbourly behaviour’ of the atoms which means in these models some silicon atoms can have three neighbours if others have five – something other techniques such as spectroscopy show is incorrect.

The new insight relates to the fact that such experiments are sensitive to the number of neighbours each atom has, so an atom with three neighbours would appear as a different ‘type’ of atom to one with five neighbours.

‘Because there is only one ‘type’ of atom observed for silicon we know that not only is the average number of neighbours equal to four, but that each silicon atom must have exactly four neighbours,’ Andrew adds.

‘If we incorporate this extra information when building a model, the answer seems to fall out almost straight away. We simply tell our program how many different types of atom there are, and in what proportions, and this is enough to produce a realistic model from the ring-like patterns.’

The findings suggest that crystallography might, after all, be able to unlock the structural secrets of some of Nature’s most irregular materials: opening the way for new kinds of science and powerful new technologies.

Dr Andrew Goodwin is based at Oxford University's Department of Chemistry.

Image: Ring-like pattern observed using crystallographic techniques, in this example silicon has been used.

The first UK trial of a promising new retinal implant technique is to be led by Oxford University researchers.

The technology, developed by the firm Retinal Implant, AG, involves implanting a device underneath a patient's retina.

The device itself is light sensitive, with a 1,500 pixel array, and is stimulated by the natural image focused by the eye - eliminating the need for an external camera (typically mounted on spectacles).

Retinal implants hold particular promise for the treatment of retinitis pigmentosa (RP) a form of inherited retinal degeneration affecting approximately 200,000 people worldwide that typically causes severe vision problems in adulthood.

The trial will be led by Professor Robert MacLaren of Oxford University's Nuffield Laboratory of Ophthalmology. 'I have been working in developing new treatments for patients with retinal diseases for many years and I was initially sceptical about the role of electronic devices,' he said.

'However, this recent work by the Retina Implant team is very impressive indeed and I would now certainly consider this technology as a viable treatment option for patients blind from RP.'

He described it as 'much more logical' to implant a device underneath the retina, as this is 'where the residual neurons are orientated towards the implant electrodes, because this should equate to a much higher pixel resolution.'

Making the implant itself light sensitive is, he believes, a major advance 'because the whole device can be contained within the eye. A power supply is fed through a battery behind the ear similar to a hearing aid.'

'This represents a true fusion of an electronic interface with the human central nervous system and we are likely now to learn a lot more about this technology as the trial progresses.' 

The Oxford-led clinical trial using the technology, which will take place at the John Radcliffe Hospital, is due to start later this year.

Images: courtesy of Retinal Implant, AG.

A hydrogel material promises better treatment for cleft palates - a birth defect that affects 1 in 700 babies in the UK.

As today's Daily Mail reports the breakthrough comes from work by researchers at Oxford University, the John Radcliffe Hospital, and the Georgia Institute of Technology using STFC's ISIS neutron source.

The team, including Jinhyun Hannah Lee and Zamri Radzi from Oxford University's Department of Materials, used ISIS to look at the hydrogel polymer's molecular structure in order to see how the material might be used as part of a simplified surgical treatment.

The treatment involves inserting an anisotropic hydrogel material - similar to that used in contact lenses - under the mucosa of the roof of the mouth.

Once inserted, the hydrogel gradually expands as fluid is absorbed, encouraging skin growth over and around the plate. After sufficient skin has been generated to repair the palatal cleft, the plate is removed and the cleft is repaired using this additional tissue.

The success of the preliminary results of self-inflating anisotropic hydrogel tissue expanders means clinical trials are expected to take place early in 2011.

The study is the first to be carried out using the Offspec instrument at the recently opened second target station at ISIS.

Offspec is the world’s most advanced neutron instrument for studying new surface structures and can be used for a number of applications including biological membranes and patterned materials for data storage media.

Read more about the research in this ISIS release

Oxford University's technology transfer company Oxford University Innovation is looking for commercial partners to help develop the technology, for more details, contact Renate Krelle: [email protected]

The reddest part of Jupiter’s Great Red Spot corresponds to a warm core within this otherwise cold storm system.

The discovery comes from new thermal images taken by ground-based telescopes that have enabled scientists to make the first detailed interior weather map of the Solar System’s biggest storm.

The international team, including scientists from Oxford University and NASA JPL, used thermal images from the Very Large Telescope (Chile), Gemini Observatory telescope (Chile) and Japan’s Subaru telescope (Hawaii). They report their findings in the journal Icarus.

‘This is the first time we can say that there’s an intimate link between environmental conditions - temperature, winds, pressure and composition - and the actual colour of the Great Red Spot,’ lead author Leigh Fletcher, from Oxford University’s Department of Physics, told me.

‘Although we can speculate, we still don’t know for sure which chemicals or processes are causing that deep red colour, but we do know now that it is related to changes in the environmental conditions right in the heart of the storm.’

As well as this warm ‘heart’ the images show dark lanes at the edge of the storm where gases are descending into the deeper regions of the planet.

One of the most intriguing findings is that the most intense orange-red central part of the spot is about 3 to 4 Kelvin warmer than the environment around it.

Leigh explains that while this temperature differential might not seem like a lot it is enough to allow the storm circulation, usually counter-clockwise, to shift to a weak clockwise circulation in the very middle of the storm. Not only that, but on other parts of Jupiter the temperature change is enough to alter wind velocities and affect cloud patterns in the belts and zones.

‘This is our first detailed look inside the biggest storm of the solar system,’ said Glenn Orton, a senior research scientist at NASA’s Jet Propulsion Laboratory, one of the authors. ‘We once thought the Great Red Spot was a plain old oval without much structure, but these new results show that it is, in fact, extremely complicated.’

Unlocking the secrets of Jupiter’s giant storm systems will be one of the targets for infrared spacecraft observations from future missions including NASA’s Juno and the NASA/ESA Europa-Jupiter System Mission concept.

Dr Leigh Fletcher is based at Oxford University’s Department of Physics

In the 1970s Oxford University engineer John O’Connor with surgeon John Goodfellow invented the Oxford Knee.

This prosthetic device, which has gone through many incarnations since, is an alternative to complete knee replacement, helping patients recover mobility faster after the operation and giving them an implant that, in over 90 per cent of cases, lasts for over 20 years.

It’s a great example of where an engineering idea results in a successful new medical technology but for every success story are other ideas that aren’t as commercially viable or don’t address a real clinical need.

So how can we ensure that tomorrow’s young engineers invent new technologies that will transform patients’ lives?

Ideas into products
Part of the answer could be found in the new Centre for Doctoral Training [CDT] in Healthcare Innovation which is officially launched today at Oxford University’s Institute of Biomedical Engineering [IBME].

It’s one of 44 new CDTs supported by the Engineering and Physical Sciences Research Council [EPSRC] as a focal point for PhD training in the UK - Oxford now has four such centres.

‘Biomedical engineering is an applied subject that aims to have clinical impact,’ Alison Noble Director of the CDT, tells me, ‘so it’s important to understand  that not all good research ideas make good products, and that listening to customer needs, in our case clinicians, can suggest the best research questions to work on that lead to useful solutions – and profits.’

The new centre aims to equip a new generation of postgraduate researchers not just with traditional academic biomedical engineering skills, but with an appreciation of the clinical environment in which new inventions have to succeed, and the routes to commercialising a new product or service.

So what’s different about training at the CDT?

‘The traditional doctoral training route focuses on research training in one sub-discipline of biomedical engineering. This is an excellent route for students who know exactly which research area they want to work in, but the onus is on the student to fill in their gaps of knowledge and build up an interdisciplinary skills base,’ Alison tells me.

‘By contrast the CDT programme provides a solid grounding of advanced biomedical engineering research skills and an introduction to healthcare technology commercialisation and clinical translation up-front in the first year.’

Understanding these issues from the very start of their doctoral training, before they specialise, is, she believes, very important so that this understanding can inform the development of each student’s research.

As part of the 4 Year DPhil programme at the CDT students cover three key themes; Information Driven Healthcare, Modelling for Personalised Healthcare and Cancer Therapeutics and Delivery.

Software to cancer therapy
Each theme is an area already being investigated at the IBME, so in information-driven healthcare, for instance, Oxford researchers are currently looking how to use intelligent signal processing methods to automate the monitoring of signals from devices in the ITU, and developing software-based clinical decision-support systems for monitoring breast cancer treatment.

Whilst in cancer therapeutics and delivery on-going research includes work on molecular imaging, development of ultrasound-based methods for detecting early response to cancer therapy, monitoring of high-intensity focused ultrasound, and new drug delivery technologies.

But the programme is about more than academic research:

‘We want students to consider careers in industry as well as academia and we offer various activities over the 4-year programme: business and entrepreneurship modules, seminar series, events, and placements or PhDs involving industry partners,’ Alison explains. ‘These aim to expose students to the breadth of the healthcare industry and associated businesses to enable them to make an informed decision about their future careers.’

The goal is for the CDT to form the focal point for postgraduate training at the IBME over the next 8 years, with an estimated 75-100 students passing through the programme, providing an invaluable alternative to traditional doctoral training.

Alison tells me: ‘we want to make the CDT a flagship postgraduate programme in the UK and internationally, and judging by the quality of overseas applications we are receiving, it has strong global appeal. We already have one university-funded overseas scholarship and are looking to raise funds for more.’

‘Our aim is, whether they work in industry or academia, for our graduates to go on to become global leaders in their field.’

Professor Alison Noble is Director of the new CDT and is based at the IBME, part of Oxford's Department of Engineering Science.