Research Horizons

Pioneering research from the University of Cambridge

Issue 24

Spotlight Advanced materials

Feature Invisible infertility & fragile masculinity

Feature D-Day’s forgotten commander www.cam.ac.uk/research Issue 24, June 2014 2 Contents Contents

News Things

4 – 5 Research news 16 – 17 D-Day’s forgotten commander

Features Spotlight: Advanced materials

6 – 7 Synthetic plants 18 – 19 Super steel

8 – 9 Male infertility 20 – 21 Gallium nitride LEDs

10 – 11 Irish literary history 22 – 23 Biological scaffolds

12 – 13 Bronze Age mystery 24 – 25 Graphene and carbon nanotubes

14 – 15 Reducing the risk of stillbirth 26 – 27 Nanophotonics

3 Research Horizons

Welcome

28 – 29 Wooden skyscrapers Advanced materials have a lot to live up to: according to the UK government, they are one of the “eight great technologies which will 30 – 31 Perovskite propel the UK to future growth and help it stay ahead in the global race.” With potential uses in applications like low-energy lighting and 32 – 33 Atomic building electrical wiring, advanced materials are an essential part of a future that is more energy efficient and less demanding of natural resources. They also underlie the technical wizardry that could give us mobile phones with in-built health diagnostics, windscreens with real-time Extreme sleepover information updates and even energy-generating clothes. Broad applications they may be, but at the heart of each material lie step changes that are taking place in the engineering 34 – 35 In the Atlantic Ocean or processing of materials to be stronger, cheaper, lighter, more conductive – simply better. The field of advanced materials has long been a research strength in Cambridge, and we cover some of the new developments in this area in this issue. With recent large-scale investments in infrastructure, and doctoral training and research programmes, we aim to continue to design materials with radically altered functionality, and take these from discovery through to application. Another area that depends on the production of new forms is synthetic biology. In this issue, we describe how a new open-access initiative in Cambridge plans to help synthetic biologists build new forms of plants to make food, fuel, chemicals and drugs. Elsewhere, readers will find coverage of Bronze Age archaeology and Ireland’s literary legacy, as well as two articles on reproductive health – research aimed at reducing the risk of stillbirth and a study uncovering the societal silence around male infertility. Finally, we continue the Extreme Sleepover series, in which we hear about some of the experiences of our researchers in the pursuit of their studies. This issue, Earth Sciences PhD student Julia Gottschalk tells us about her mud-spattered trip aboard a “science factory” floating on the Atlantic Ocean.

Professor Lynn Gladden Pro-Vice-Chancellor for Research

Editor Dr Louise Walsh

Design The District

Printers Micropress

Contributors Sarah Collins, Tom Kirk, Fred Lewsey, Stuart Roberts, Louise Walsh

T +44 (0)1223 765 443 E [email protected] W www.cam.ac.uk/research

Copyright ©2014 University of Cambridge and Contributors as identified. The content of Research Horizons, with the exception of images and illustrations, is made available for non-commercial re-use in another work under the terms of the Creative Commons Attribution-Non-Commercial-ShareAlike Licence (http://creativecommons.org/ licenses/by-nc-sa/3.0/), subject to acknowledgement of the original author/s, the title of the individual work and the University of Cambridge. This Licence requires any new work with an adaptation of content to be distributed and re-licensed under the same licence terms. Research Horizons is produced by the University of Cambridge’s Office of External Affairs and Communications. 4 News News

Investment to open new Credit: Stefanie Reichelt / Hironobu Fushiwara Hironobu / Reichelt Stefanie Credit: frontiers in astronomy

A £119 million boost will help astronomers, including researchers in Cambridge, to unveil the mysteries of the origin and evolution of the Universe.

Vast networks of radio telescopes are being built in Australia and Africa that, together, will provide a ‘collecting’ area of over one square kilometre. When fully operational Image in 2028, the Square Kilometre Array (SKA) Picture 3D confocal image will be able to survey the sky 10,000 times reconstruction of mouse skin faster than any radio telescope to date. this In March, the Science and Technology Facilities Council announced a major boost What links astronomers with oncologists, 200 years, is now less than 100 nanometres for the global project: £119 million for and chemists with art historians? “The desire with light. We can link imaging of whole the UK’s contribution of phase 1 of to visualise and record what no one has organisms with molecular detail in real time.” the instrument and to support the UK’s seen before.” The organisers view the multi- leading role in designing the computing disciplinary approach of the IMAGES and software that will underpin the SKA. In today’s digital world, an image can network – which currently spans 25 groups As part of the UK involvement, convey far more than a thousand words. across the arts and sciences – as a vital researchers at Cambridge’s Cavendish Technological advances have made forum for discovering and sharing new Laboratory, Department of Physics, are imaging a powerful tool, but until now tools and new perspectives. leading the Science Data Processor there has been little sharing of expertise “As developers of image analysis consortium and have a major role in the across disciplines. and processing methods, we are keen Low Frequency Aperture Array consortium. IMAGES, a recently launched network to overcome limitations in imaging The volume of data the SKA will in Cambridge, is redressing this balance by technologies that arise in applications,” produce is vast, amounting to around encouraging the sharing of software and said Dr Carola-Bibiane Schönlieb 20 times the current global traffic of the instrumentation developments, as well as (Department of Applied Mathematics and internet in its internal telecommunications of scientific ideas and proposals. Theoretical Physics), co-organiser of the system. In fact, to play back a single day’s “We are connected by the desire to network with Reichelt and Professor worth of SKA data on an MP3 player would visualise and record what no one has seen Stella Panayotova (The Fitzwilliam take 2 million years. The University’s before,” said Dr Stefanie Reichelt, from Museum). “A continuous dialogue High Performance Computing Service CRUK Cambridge Institute. “Imaging has with applied imaging researchers is will help researchers test the scalability of never been as exciting as it is now, with therefore essential to make advances in architectures to the enormous proportions new technologies emerging all the time. imaging research.” needed for the SKA. The resolution limit in light microscopy, which had seemed unbreakable for www.images.group.cam.ac.uk www.skatelescope.org

News in brief 14.05.14 06.05.14 Cambridge has signed the An £8 million donation by the James Dyson More information at Concordat on Openness on Animal Foundation will provide Cambridge’s Research in the UK, joining over brightest engineers with some of the www.cam.ac.uk/research 70 organisations. world’s most advanced laboratories. 5 Research Horizons

Image Roman CGI view of the inner canal entrance rethink

New archaeological discoveries will lead help the Italian authorities manage this to a major rethink of one of the iconic important area effectively. Roman cities in the Mediterranean, Now, a team led by Cambridge’s Credit: ©The Portus Project say researchers. Professor Martin Millett and Southampton’s Professor Simon Keay has shown that Ostia is The harbours and port facilities at the great far larger than previously thought, stretching twin sites of Ostia and Portus, at the mouth northwards beyond the Tiber. Moreover, the of the river Tiber, linked Rome with its whole recent finding of warehouses, including one Empire in the first two centuries via a network the size of a football pitch, along the northern of maritime routes forming the hub of the bank of the river provides further evidence Empire’s supply network. for the commercial activities that took For over a decade, researchers at place there. the Universities of Southampton and “The results of our work completely Cambridge, with colleagues in Italy, have transform our understanding of one of the been unearthing the treasures of these sites key cities of the Roman Empire,” said Millett, 30 miles from Rome. Using state-of-the- from the Faculty of Classics. “The enormous art geophysical techniques and funded by scale of the newly discovered warehouses the Arts and Humanities Research Council, will require a rethinking about the scale of the Portus Project has been gaining a fuller commerce passing through the port.” understanding of the site’s development, as well as providing information that will www.portusproject.org

Clinical trials have shown that the Department of Pathology in the late Alemtuzumab, marketed under the name 1970s as an immunosuppressant to prevent Lemtrada, reduces MS activity, limits the the rejection of bone marrow. However, accumulation of further disability over time the story of Campath stretches even further and may even allow some existing damage back, to research by Nobel-Prize-winning to recover. The decision by the National Dr César Milstein at Cambridge’s MRC Institute for Health and Care Excellence Laboratory of Molecular Biology in 1975 (NICE) brings to a conclusion work involving on monoclonal antibodies. several research groups in Cambridge, Compston identified Campath-1H stretching back over decades. as a potential treatment for MS in the late Professor Alastair Compston, Head 1980s. The first MS patient was treated of Cambridge’s Department of Clinical with the drug in 1991 and, as evidence Neurosciences, said: “I am delighted that began to mount that the drug would be the decision from NICE will make Lemtrada effective if used to treat people before NICE approves available on the NHS. [It] now provides an the disease process had progressed opportunity for neurologists to offer a highly too far, Compston and his colleague MS drug effective therapy for patients with MS early Dr Alasdair Coles expanded the trials. in the course of their illness.” The results of phase III clinical studies, Lemtrada, manufactured by published in 2012, confirmed that the drug A new drug based on decades of research pharmaceutical company Genzyme, began is effective both in MS patients who are at the University of Cambridge has been life as Campath-1H, a drug developed previously untreated (‘first-line’ therapy) approved for use in people with relapsing- out of research by Professor Herman and those who have already failed remitting multiple sclerosis (MS). Waldmann and colleagues in another treatment.

01.05.14 28.03.14 26.02.14 The government has approved Cambridge has been awarded Research growing ‘mini-livers’ a £165 million deal for Papworth EPSRC funding for two new from adult mouse stem cells has Hospital to move to the Cambridge doctoral training centres in won the NC3Rs prize for reducing Biomedical Campus. sensing and analysis. animal use in science. 6 Features

From foundry to factory building synthetic plants Synthetic biologists choose a ‘chassis’ and then bolt on standard parts to build something movement is under way that will fast-forward the design of new that’s tailor-made A plant traits. It takes inspiration from engineering and the software industry, and is being underpinned in Cambridge and Norwich by an initiative called OpenPlant.

Humans have been modifying plants for millennia, domesticating wild species and creating a bewildering array of crops. Modern agriculture allows global cultivation of plants at extremely low cost, with production on the gigatonne scale of a wide range of biostuffs – from fibres, wood, oils and sugar, to fine chemicals, drugs and food. But, in the 21st century, we face both Images ever-increasing demand and the need to Marchantia – a primitive plant form shift towards more sustainable production used as the ‘chassis’ for designing systems. Can we build new plants that make new plants better materials, act as miniature ‘factories’ for food and fuel, and minimise the human impact on the environment? With this in mind, synthetic biologists are beginning to build new organisms – or at least reprogramme existing organisms – by turning the biology lab into an engineering foundry. Synthetic biologists choose a ‘chassis’ and then bolt on standard parts – such as genes, the promoters that activate them and the systems they drive – to build something that’s tailor-made. And, like open-source software programmers, they have been looking to open-access and the sharing of code – in this case the DNA that codes for each part – as a practical means of speeding up innovation. “Providing free access to an inventory of molecular parts for use in the construction of diverse plant-based systems promotes their creative use by others, just as the open-source feature has driven innovation in the computer software industry,” explained and the Engineering and Physical Sciences Professor Sir David Baulcombe from Research Council. Cambridge’s Department of Plant Sciences. OpenPlant aims to establish the first Earlier this year, the University of UK open-source DNA registry for sharing Cambridge and the John Innes Centre in specific plant parts. It will also support Norwich received £12 million in funding for a fundamental science: “Construction new UK synthetic biology centre – OpenPlant of these parts will allow us to test our – to focus on the development of open understanding of natural plant systems in technologies in plant synthetic biology and which assemblages of parts create a greater their application in engineering new crop whole,” Baulcombe explained. traits. The effort is being led by Baulcombe Researchers like Baulcombe and and Dr Jim Haseloff in Cambridge, and by Haseloff, who also leads a new Strategic Professors Dale Sanders and Anne Osbourn Research Initiative to advance cross- Left to right in Norwich. disciplinary research in synthetic biology in Dr Jim Haseloff It’s one of three new UK centres for Cambridge, believe that the investment in the [email protected] synthetic biology that, over the next five three new centres will help the UK stay at the Professor Sir David Baulcombe years, will receive more than £40 million leading edge of plant synthetic biology. [email protected] in funding from the Biotechnology and “Any large-scale reprogramming of living Department of Plant Sciences Biological Sciences Research Council systems requires access to a large number 7 Research Horizons

of components and, as the number of these OpenLabTools parts balloons, the cost of building a portfolio of patents, or licensing parts from patent owners, could strangle the industry and OpenPlant is part of a wider move restrict innovation,” explained Haseloff. towards ‘sharing’ in Cambridge that “While US researchers lead in the now includes scientific tools of synthetic biology of microbes, the UK has the the trade. edge in plants. The field needs a new two-tier system for intellectual property so that new Resourcing laboratories with scientific tools including DNA components are freely tools is a costly business. An automated shared, while investment in applications can microscope, for instance, could cost Credit: All images, Jim Haseloff Jim images, All Credit: be protected.” upwards of £75,000, and yet be a key tool As well as new DNA components, in materials and biological laboratories. Haseloff and colleagues have been focusing Now, an initiative coordinated by Dr on a new plant chassis. Rather like the frame Alexandre Kabla, from the Department of of a car, the chassis is the body of the cell Engineering, is rethinking how scientists that houses the rest of the desired parts. And can access the tools that they need at a for this they have turned to liverworts, relics less-prohibitive cost. of the first land plants to evolve around He recognised that a wealth of 500 million years ago. instrument-building know-how exists The Marchantia polymorpha liverwort is across the University – expertise that small, grows rapidly, has a simple genetic could be drawn on to develop a suite of architecture and is proving such a useful low-cost open-access scientific tools. test-bed for developing new DNA circuits Raspberry Pi, for example, was that Haseloff has launched a web-based conceived and incubated in the resource (www.marchantia.org) for a growing Computer Laboratory to encourage international community to exchange children to learn programming for ideas. The hub characterises one of the themselves: this credit-card-sized wider aims of OpenPlant in promoting computer is now available for only $25. interdisciplinary exchange between The OpenLabTools initiative has fundamental and applied sciences, and is set itself the task of creating high-end one of a series of collaborative projects, tools such as microscopes, 3D printers, such as OpenLabTools (see panel), which are rigs for automation and sensors, with promoting open technology, innovation and an emphasis on undergraduate and exchange between engineers and physical, graduate teaching and research. It was biological and social scientists across created with funding from the University the University. and the Raspberry Pi Foundation, and In parallel with the development of is supported by an academic team standardised parts, the Centre will support of engineers, physicists, materials around 20 researchers and their teams in scientists, plant biologists and Cambridge and Norwich who are engineering computer scientists. new plant traits. For instance, scientists at “Current projects primarily focus on the John Innes Centre are investigating new the development of core components, systems for producing useful compounds thanks to the contributions of a team like vaccines. In Cambridge, researchers are of physics and engineering students. creating systems with altered photosynthetic However, we have already made capabilities and leaf structure to boost significant progress towards the conversion of the sun’s energy into food, development of imaging systems and as well as developing plant-based mechanical testing devices,” said Kabla, photovoltaics for fuel. whose own expertise lies in the physics Another of OpenPlant’s aims is to foster and mechanics of biological systems. debate on the wider implications of the “We anticipate that these will be rolled technology at local and global scales. As out in undergraduate laboratories Baulcombe described, “The open source sometime next year.” feature may allow straightforward discussion To encourage open access, ‘How To’ about the applications of synthetic biology manuals and designs are being published in plants. Societal discussion about other on the OpenLabTools website. strands of biotechnology has been greatly “It’s an exciting prospect,” said hampered by the complications following Kabla. “When you consider that from intellectual property restrictions.” consumer-grade low-cost microscopes “We think that biological technologies are essentially a digital camera with a are the underpinning of the 21st-century’s high magnification objective, not only industrial processes,” added Haseloff. can we build this but we can also provide “Plants are cheap and inherently sustainable, a means to automate the microscopy, and have a major role to play in our future. dramatically reducing the cost of the tool. In order to implement ideas and shift towards The blueprints and tutorials we make more rational design principles to support available will be useful for undergraduate advances, we need to have the ability to and research projects, as well as school exploit synthetic biology technologies in a activities and small-scale industrial responsive way, and that’s where we see applications running on OpenPlant contributing in the years to come.” a tight budget.”

www.openplant.org www.openlabtools.org 8 Features

ale infertility is as prevalent as “decades of misogynistic limelight on female infertility but it’s invisible infertile women has left a ‘categorical hole’ in M in our society, finds new research. medical systems, with very few male infertility specialists and no official board certification The day before the artificial insemination, for practitioners in the US,” she said. Dr Liberty Barnes’ husband came down Some men seeking treatment end up with flu, killing his sperm. The medical staff further damaged by malpractice – having assured him – incorrectly – that the fever been prescribed testosterone, for example, didn’t kill his sperm, that it was a ‘fluke’, which arrests sperm production; often this and that his wife’s infertility – the reason for is the result of them receiving treatment by the appointment – could be overcome, even specialists in the wrong areas, such as a though a scan had revealed her ovaries to general urologist or their wife’s doctor. contain healthy eggs. And those that do manage to engage “My husband’s sperm was dead and with male infertility specialists are often fed I had a live egg in the queue, yet infertility information about their disorder through was still my problem. If dead sperm doesn’t metaphors that mask infertility – frequently qualify as infertility, what does?” involving traditional male activities such For Barnes, a medical sociologist now as plumbing, sport or car mechanics – to based at the University’s Department of the point where two thirds of infertile men Sociology, the experience raised questions. interviewed for the study simply didn’t While she could find dozens of highly consider themselves infertile. regarded books on women, when it came to “This is not some kind of deep-seated infertility, men were missing – despite infertility denial on the part of these men. There is an being equally as common in both sexes. entire culture and medical system that makes Intrigued, she tried to find out more. it possible for men to be infertile and not “Initially, it seemed very strange: I couldn’t even realise it,” said Barnes, a member of the find the doctors, I couldn’t find any patients or Reproductive Sociology Research Group led figure out what the medical conditions were. It by Professor Sarah Franklin. “Male infertility was an information black hole.” is as prevalent as female infertility, but it’s Once some clinics were tracked down, invisible in our society.” research began in earnest. Barnes spent over Most cases of male infertility are referred 100 hours shadowing doctors in five clinics to IVF clinics – a process in which women in different states across the USA, as well as bear the brunt. For many, male infertility is interviewing many of the couples involved repaired in female bodies.” (men and women separately). The work Most infertile men, even those who forms the basis of a new book, do self-identify as infertile, are able to Conceiving Masculinity. ‘intellectually reframe’ their infertility issues During the research, she found a as a medical condition somehow separate “culturally sanctioned suppression of from their self, explained Barnes. dialogue around male infertility.” “This separation of body and self, while Even though male infertility is responsible rare in female infertility, is the standard for half of all cases of infertile couples, coping mechanism in men – that their

Invisible infertility & fragile masculinity 9 Research Horizons

when prescribing hormone treatment to boost testosterone, would tell patients that side effects include “the urge to hit a ball really hard or drive really fast.” Barnes describes this claim as scientifically “There is an entire debatable. culture and medical The assumed functionality of male sexual biology also translated to the first system that makes it experience of the clinic – the collection cup. Men describe being pushed into a room or possible for men to be even just behind a curtain with no instruction infertile and not beyond “fasten the lid tightly.” Medical institutions assume men can even realise it” masturbate under any conditions, will enjoy it, and be able to shoot semen straight into a cup, says Barnes. Some interviewees told her the semen they provided was both of particularly poor quality and limited due to stress and the amount they were able to catch. In fact, most men found this confusing ‘messed-up plumbing’ is not their fault and and uncomfortable – especially when in most cases repairable. Many men cling to confronted with the choice of ‘performing’ or the notion that if you have a problem that can extraction by needle from the testicle. be fixed, you don’t have a problem. Instead Barnes found the extraordinary lack of of telling these men they’re infertile, you hear medical professionals specialising in male doctors saying ‘oh, it’s just an issue with your infertility as opposed to those in female blocked exhaust.’ infertility to be part of a damaging cycle: “The doctors actually provide men with “When I spoke to organisations about this the linguistic strategies to separate body hole in the system, they would tell me it’s from self.” because it’s not needed. Men aren’t coming Culturally, male fertility is intrinsically forward for treatment, so there appears to bound up with ideas of virility, machismo be little demand. But then those that do and sexual potency because it hinges on come forward, struggle to find help, which that very essence of manliness – semen. As – combined with the social stigma – means William, a businessman in his late thirties that many give up.” interviewed for the research, puts it: “Men There is a medical and social price to should be able to gush sperm all over pay, she says. Research into male infertility is the place.” not as advanced as that for female infertility. For Barnes, the prevarication around And societal silence on the subject means male infertility is symptomatic of widespread men who want and may well be able to have cultural nervousness to expose masculinity children if treated are not. as in any way fragile: “Masculinity is equated The cultural invisibility of infertile men is with power; protecting and expressing power inherently conflicting, says Barnes. On the is a key function of societies and states.” In one hand, male infertility doctors complain the book, she cites the global media panic about the lack of attention the topic receives. around a 1992 study showing sperm counts But on the other, they realise this invisibility were dropping. protects men and masculinity by suppressing Male infertility hits masculine identities the issue. – from the personal to the national – “If you promote male infertility as a label right where it counts, says Barnes. One to encourage more men to come forward for interviewee described his desire for treatment, you will have a harder time helping fatherhood as “kind of the only purpose of them pretend they’re not actually infertile.” life.” Another said his infertility led him to “doubt the toughness” of his penis. Consequently, once a man is diagnosed, almost as much effort is taken to alleviate this perceived trauma to masculinity socially as is taken to treat it medically. When interviewed, doctors reeled out a progressive rhetoric. But in the infertility clinics, Barnes found a culture designed to enforce gender stereotypes and bolster masculinity. “Every doctor I spoke to and medical seminar I went to, I heard time and again: we’ve got to help society move past archaic ideas that reproduction is women’s work. Then when I was in the clinics, it was complete immersion in traditional gender ideology: penis jokes, talk of balls – everything was power and virility.” Diagnoses were shrouded in metaphors invoking factories/bridges/engines – Dr Liberty Barnes technological achievement hiding biological [email protected] failure. One doctor who Barnes shadowed, Department of Sociology 10 Features Credit: Isaacs Art Centre, Hawaii, on Wikimedia

resh analysis of the literary portrait of stay on record as the biggest millennial Beyond the Battle of Clontarf – a decisive battle reconstruction the world has ever seen. “For F fought a thousand years ago in Ireland our lifetime this is it,” Barry Gaynor, from the – offers a glimpse of a thriving intellectual Fingal Living History Society, enthused to the culture in the generations that followed. Irish Times. “This,” he added, “is the big one.” the blood In Ireland, children are still raised on the The Vikings were back in Dublin at Easter, story of the Battle of Clontarf, and many of this marching through the streets, screaming year’s anniversary activities follow the popular of Clontarf murderous battle cries, and demanding beer narrative. This styles the battle as a quasi- from the locals as if the last thousand years nationalistic, blood-soaked clash, between had never happened. The occasion was a the army of Brian Boru, the Irish High King re-enactment of the Battle of Clontarf, a pivotal who died at Clontarf, and an allied force led by struggle in Irish history which was fought on the rebel king of the territory of Leinster, Máel Good Friday, 23 April, 1014. For its millennium, Mórda, and Sitric, of the Dublin-based Vikings. some 500 costumed enthusiasts, dressed as Frequently, it is depicted as an Irish victory, either Viking invaders or Irish warriors, met which, with Brian’s death, came at a high price. in St Anne’s Park to reconstruct the bloody Recently, a Dublin-based historian has even encounter. Another 40,000 spectators turned asked whether Clontarf is “a medieval version Image up to watch. of 1916” – likening it to the Easter uprising, Battle of Clontarf Until the anniversary of the Battle of in which a later generation of Irishmen were by Hugh Frazer (1826) Hastings in 2066, this rematch is likely to martyred in the national cause. 11 Research Horizons

Re-enactments aside ... Clontarf remains a significant but mysterious moment in Ireland’s past, defined by an account which is as unreliable as it is popular

Equally, researchers have long pointed Close reading of this Hector comparison Such remarkable, creative scholarship out that the reality was more complex. For reveals that it drew in a sophisticated manner was, Ní Mhaonaigh argues, the achievement example, both Irish and Vikings clearly fought on an Irish translation of a 5th-century, Latin “of a consummate craftsman with a particular on both sides at Clontarf, while the outcome account of Troy by Dares Phrygius called De tale to tell.” More than a copy of Togail Troí, it – which seems something of a gory stalemate excidio Troiae historia, which became a staple would have demanded extensive learning, and – is just as doubtful as its nationalistic basis of medieval scholarly fascination with the access to wide-ranging cultural knowledge connotations. The debate is not helped by Trojan war. Tellingly, this Irish version – Togail and resources. scarce evidence from the battle itself. No Troí – also appears in the very same manuscript So where does it leave Clontarf, Murchad archaeological remains have survived and we in which the earliest (albeit fragmentary) version and Brian? Ní Mhaonaigh stresses that their still don’t know exactly where the battlefield of the Cogadh is found. It is hardly a leap to legacy was, in part, Cogadh itself. “This was was. Contemporary records offer little more suggest that, given the similarities, whoever the work of a sophisticated and learned than a date and a list of the dead; otherwise, wrote the story of Clontarf had it to hand. author,” she added, “skilfully weaving a we are reliant on later, more suspect accounts. Yet while this makes the conventional story cloth of his own design reflecting motifs and Of these, the most influential is called of Clontarf more literary history than historical patterns from his entire scholarly wardrobe.” Cogadh Gáedhel re Gallaibh (The fact, the document itself is a masterpiece. Re-enactments aside, then, Clontarf War of the Irish Against the Foreigners), Through it, we catch sight of a vision of remains a significant but mysterious moment a remarkable work which is the subject of a medieval Irish culture which, by the 12th in Ireland’s past, defined by an account which new study by Dr Máire Ní Mhaonaigh, from century, was achieving standards that rivalled is as unreliable as it is popular. Yet at the the Department of Anglo-Saxon, Norse and anything being produced in continental Europe same time, Cogadh offers a glimpse into the Celtic. Written about 100 years after the date at the time. vibrant intellectual world of the generations of the battle, it was probably commissioned Whoever wrote Cogadh was highly that followed. If its trustworthiness is in doubt, by Brian’s great-grandson, Muirchertach, sophisticated, and deeply learned. Far from its value as a work of literature seems beyond who was then the most powerful king in merely comparing Murchad to Hector, the question. Perhaps sensibly, however, nobody Ireland. Academics are rightly suspicious author places the Irish leader at the end of a has yet raised this rather subtle distinction of its depiction of Clontarf, seeing it as list of six great-warrior heroes, starting with with the latest horde of Dublin Vikings. skilful propaganda. Hector himself. This consciously imitates the Ní Mhaonaigh’s research, however, shows idea of a world with six “ages” represented by Cogadh to be something more – not merely six different stages of human life, from infancy, a partisan propaganda piece, but a brilliant through to old age. The concept, which dates work of art. “It is in this text that Brian’s image back to the 5th century, suggests that world was cultivated, and our perception of Clontarf history is one of gradual decline after a golden owes much to its learned author’s pen,” she youth. It was a recurring motif in the culture said. “Whatever the precise nature of the of medieval Europe, appearing, for example, battle, its cultivation as literary history tells in the work of Bede and the stained glass another, very important story.” windows of Canterbury Cathedral. Unfortunately for the re-enactment Cogadh’s author, however, did something enthusiasts, this also makes it an even less completely new, incarnating the six ages credible account of what happened. In fact, with six heroes, through whom we trace part of the depiction of the battle appears to the progressive descent of valour. He even have been based on an earlier work about calculated this mathematically: seven of each the siege of Troy. During a powerful, rousing hero are required to match the ability of his passage, the unknown author of Cogadh predecessor on the list, according to which it likens Brian’s son, Murchad, to the Trojan would have taken 16,807 Murchads to match hero, Hector. Murchad led Brian’s army at a single Hector. Murchad is the last, great hero Dr Máire Ní Mhaonaigh Clontarf (Brian himself was probably in his 70s the world will ever see, the author suggests, [email protected] at the time), and the author casts him as adding, rather despondently, that “it will be a Department of Anglo-Saxon, “the last man who had true valour in Ireland.” palsied, drivelling dotard ever after.” Norse and Celtic 12 Features

Whatever happened to the Harappans?

? Exhausted their resource base ? Population increased ? Glacier-fed rivers changed their course

? Trading economy broke down ? Climate change ? Succumbed to invasion and conflict

he Harappan Civilisation of ancient painting representations of themselves summer monsoon, causing long-term Pakistan and India flourished 5,000 all over their temples – is only part of the drought in north-west India around 4,100 T years ago, but a thousand years later mystery that surrounds the people of the years ago, was likely to have been a factor in their cities were abandoned. Researchers Indus Civilisation. this process. are piecing together what could have Indus cities – like Harappa in present- Intriguingly, the finding links the onset happened to this sophisticated Bronze day Pakistan and Rakhigarhi in India – of the decline of the Indus cities to a Age society of master builders and flourished in the mid-to-late third millennium documented global-scale climate event, master craftsmen. BC. However, by the start of the second which also had an impact on Old Kingdom millennium BC, their great urban centres Egypt, the Early Bronze Age civilisations of Often regarded as ‘faceless’, the Harappan had dramatically reduced in size or been Greece and Crete, and the Akkadian Empire or Indus Civilisation was a society who built completely abandoned. in Mesopotamia. ‘megacities’ and traded internationally in Now, researchers from Cambridge’s “There is plenty of archaeological luxury craft products, and yet seemed to Department of Archaeology and evidence from the five known large or have left almost no depictions of themselves. Anthropology and Department of Earth ‘megacities’ that have been found over the But their lack of self-imagery – at a Sciences have provided the first evidence past century to tell us about the rise of the time when the Egyptians were carving and that a widespread weakening of the Indian Indus Civilisation, but relatively little about 13 Research Horizons

It has long been suggested that other great Bronze Age civilisations also declined at a similar time, with a global-scale climate event being seen as the cause

its fall,” explained archaeologist Dr Cameron archaeological sites were not where they “Inevitably, the weakening monsoon must Petrie. “As populations increased, cities were were supposed to be, completely altering have had some impact on the population,” built that had great baths, craft workshops, understanding of the way that this region added Petrie. “We now have people looking palaces and halls laid out in distinct sectors, was inhabited in the past. at the detailed archaeological record and the and these centres covered a total area When they carried out a village-to- seed grains that people were using. We’re roughly the size of 100 football pitches. village survey of how the larger area was trying to work out whether the grains were Houses were arranged in blocks, with wide settled in relation to sources of water, they grown under extreme conditions of water main streets and narrow alleyways, and many found errors in the published geographic stress and whether they were adjusting the had their own wells and drainage systems. It locations of ancient settlements ranging from combinations of crops they were growing was very much a ‘thriving’ civilisation.” several hundred metres to many kilometres. for different weather systems. We are really Then around 2100 BC, a transformation They realised that any attempts to use the trying to understand details of how people began. Occupation in the cities seemed to existing data were likely to be fundamentally led their lives. This includes looking at have increased, then streets went uncleaned, flawed. Over the course of several seasons whether the types of pottery that they used buildings started to be abandoned, and of fieldwork they carried out new surveys, and other aspects of their material culture ritual structures fell out of use. After their finding in consecutive years an astonishing were distinctive to specific regions or were final demise, a millennium passed before 73 and 125 settlement sites that were more similar across larger areas. This really large-scale cities appeared once previously unknown. gives us insight into the types of interactive more in South Asia, some of which went Now, research published in the journal networks that the population was involved in, on to become capitals of the great Ganges Geology by former Gates scholar Dr Yama and whether those changed.” Kingdoms. Dixit and Professor David Hodell, both from Petrie believes that archaeologists are Some have claimed that major glacier- the Department of Earth Sciences, and Petrie in a unique position to investigate how past fed rivers changed their course, dramatically has provided the first definitive evidence for societies responded to environmental and affecting the water supply and agriculture; climate change affecting the plains of north- climatic change: “How did these populations or that the cities could not cope with an western India, where hundreds of Indus sites cope with less water? Were their existing increasing population, they exhausted their are known to have been situated. ways of life resilient? Were they forced to resource base, the trading economy broke The researchers collected Melanoides adapt to survive and, if so, what did they do? down or they succumbed to invasion and tuberculata snail shells from the sediments “By investigating responses to conflict; and yet others that climate change of an ancient lake in Haryana and used environmental pressures and threats,” he caused an environmental change that geochemical analysis as a means of tracing added, “we can hopefully learn from the affected food and water provision. the climate history of the region. “As today, past to engage with the public, and the “It is unlikely that there was a single the major source of water into the lake relevant governmental and administrative cause for the decline of the civilisation. throughout the Holocene is likely to have bodies, to be more proactive in issues such But the fact is, until now, we have had little been the summer monsoon,” said Dixit. as the management and administration solid evidence from the area for most of “But we have observed that there was an of water supply, the balance of urban and the key elements,” said Petrie. “A lot of the abrupt change about 4,100 years ago, when rural development, and the importance of archaeological debate has really only been the amount of evaporation from the lake preserving cultural heritage in the future.” well-argued speculation.” exceeded the rainfall – indicative of For the past seven years, Petrie has co- a drought.” led a project to understand what happened Hodell added: “We estimate that the to the Harappans with Dr Ravindanath weakening of the Indian summer monsoon Singh of Banaras Hindu University in India, climate lasted about 200 years before investigating the archaeology, river systems recovering to the previous conditions, which and palaeoclimate of north-west India. we still see today.” Funded primarily by the British It has long been suggested that other Council UK–India Education and Research great Bronze Age civilisations also declined Initiative, and also by the British Academy, at a similar time, with a global-scale climate Natural Environment Research Council, event being seen as the cause. While it is Isaac Newton Trust and McDonald possible that these local-scale processes Institute for Archaeological Research, were linked, the real archaeological interest the multidisciplinary project involves lies in understanding the impact of these archaeologists, earth scientists and larger-scale events on different environments geographers in Cambridge working together and different populations. Left to right with researchers at Imperial College London, “Considering the vast area of the Dr Cameron Petrie the University of Oxford, the Indian Institute Indus Civilisation with its variable weather [email protected] of Technology Kanpur and the Uttar Pradesh systems,” explained Singh, “it is essential Department of Archaeology State Archaeology Department. that we obtain more climate data from areas and Anthropology Almost immediately after the project’s close to the two great cities at Mohenjodaro Professor David Hodell beginning in 2008, the field reconnaissance and Harappa and also from the Indian [email protected] team discovered that many of the Punjab.” Department of Earth Sciences 14 Features Getting the true measure of pregnancy

ne in 200 babies dies before might be offered ultrasound, biochemical “Our primary aim birth in the UK. A study aimed at screening and genetic analysis, as well as O determining how to reduce the risk an early delivery if their baby should show is to generate of a pregnancy coming to a devastating signs of difficulty – most stillbirths occur in end is now producing its first results. women with no known risk factors. clinically useful For these low-risk women, the current “I’ve spoken to many bereaved parents and provision of antenatal care – established screening tests the loss of a baby has a profound and life- in 1929 – still relies on the use of a tape long impact,” said Gordon Smith, Professor measure. that allow us to of Obstetrics and Gynaecology. “There’s “We estimate that over half of the 4,000 a whole life to be gained if you identify a stillbirths a year in the UK are the result of focus medical care baby who will die in the womb at 40 weeks placental dysfunction, which is frequently of pregnancy, and this huge gain can be associated with impaired growth of the on women who are achieved relatively easily by early delivery fetus. Apart from urine and blood pressure of the baby at 38 or 39 weeks.” monitoring for pre-eclampsia – one of the truly high risk for Smith leads the Pregnancy Outcome conditions that can cause stillbirth – the Prediction (POP) study, which aims to standard means of identifying a baby that’s complications” determine both the risk women face small for gestational age in low-risk women of losing their baby during their first is measuring the mother’s ‘bump’ with a pregnancy and how this can be reduced. tape measure,” Smith explained. Although some women are identified Globally, every year 2.6 million babies as high risk for pregnancy complications are stillborn and 3.2 million live-born from their family or medical history – and children die in the first month of life. 15 Research Horizons

“Growth-restricted and premature children will include more-intensive monitoring and Every year globally can also suffer difficulties at delivery, earlier delivery.” childhood diseases, and educational, The situation with stillbirth has parallels social and health problems in later life. with sudden infant death syndrome (Sids), The emotional cost to families, coupled explained Smith: “In the 1980s, 1 in 500 with the associated healthcare and social babies died of Sids. But when research costs, means that research into the showed that sleeping on the front was a risk prevention of these conditions is more factor for the baby, this was followed by a crucial than ever.” public health campaign that reduced Sids Smith’s approach in the Department by 80–90%. Although the strategy to reduce of Obstetrics and Gynaecology, funded by stillbirth is unlikely to be as simple, one the National Institute for Health Research area that we can look at is whether we can (NIHR), was to monitor more than 4,500 generate biomarkers for the antecedents women during their first pregnancy at of stillbirth, and use these for population- 2 6 several stages until the end of pregnancy. based screening.” million babies are As well as regular ultrasound scans and Smith believes that placental blood sampling, maternal and paternal dysfunction might result in ‘a signature’ of stillborn and DNA samples were taken and, at the biomarkers that can be used to identify a time of delivery, samples of placenta, problem with the placenta even in a mother fetal membranes and umbilical cord were showing no symptoms, and he and others collected, together with details of the have identified several potential candidates. delivery and baby. Many of these studies address Completed a few months ago, the identifying a failing placenta. However, study has been a massive undertaking, but what remains uncertain is why the placenta one that Smith says has laid the basis for is dysfunctional in the first place. “One years of in-depth analysis: “With this core possible initiating factor is infection. resource of data and biological samples Consistent with this, some studies we can now ask whether there are novel have reported high rates of placental biomarkers to identify women at high risk inflammation in pregnancies with adverse of developing pre-eclampsia – something outcomes, but the evidence so far is poor.” that would be especially useful in low – and The search for an infectious agent, 3 2 middle-income countries where scanning possibly even a currently unrecognised million live-born may not be available. We can also ask bacterium or virus, has now begun, thanks questions such as is inflammation of the to a new four-year £1.6 million project children die in the placenta more common in complicated funded by the Medical Research Council pregnancies and can this be detected by using the data and biological samples first month of life measuring circulating markers?” gathered by the POP study. Smith and One of the first questions the team colleagues will be working with Professor asked was how effective routine ultrasound Sharon Peacock from the Department scans are as a screening test for babies of Medicine and Dr Julian Parkhill and who are small for gestational age; such Professor Paul Kellam from the Wellcome babies are thought to account for about Trust Sanger Institute, as well as industrial 30–40% of stillbirths. partners. “Although previously published It’s an intriguing possibility that some research had shown no beneficial effect hitherto unrecognised infectious agent of routine screening for identifying small might lead to a significant proportion of babies in the third trimester of pregnancy,” pregnancy complications. If so, there would said Smith, “it was unclear whether this be the possibility of treatment or vaccination was because ultrasound performed to prevent complications, in the same way poorly as a screening test, or whether the that women are now vaccinated against associated interventions were ineffective.” human papilloma virus to prevent cervical Smith and colleagues have now clearly cancer. shown that routinely scanning women “That said, the idea that we could during pregnancy increases the detection come up with one magic solution for of the smallest babies from 32% to 77%. pre-eclampsia or stillbirth is beyond “The problem with previous studies everyone’s expectations at the moment. is that they were designed without More realistically, it would seem plausible any information on how well scanning that diverse infectious agents could impair performed as a screening test. We now the function of the placenta, perhaps by know that ultrasound actually performs activating some common pathway,” he very well compared with screening tests explained. used in other areas of medicine. We are The overarching goal of the now focusing on how to differentiate Department’s research is to apply state- between healthy small babies and those of-the-art approaches in clinical study who are small due to a pathological design, biostatistics, molecular biology and process. When we can achieve this, we will sequencing to develop novel tools that will be able to identify the babies most likely to help differentiate between a healthy and benefit from intervention.” an unhealthy pregnancy. “Our primary aim “Practice only changes when guidelines is to generate clinically useful screening change, and guidelines only change when tests that allow us to focus medical care the evidence to support change is strong,” on women who are truly high risk for Professor Gordon Smith said Smith. “When we have refined our complications, and to avoid ‘medicalising’ [email protected] screening test, a next step may be large- the experience of pregnancy and birth for Department of Obstetrics scale trials of screening. The interventions the women who are at low risk.” and Gynaecology 16 Things

Things D-Day’s forgotten commander Images Film available Photos and Ramsay’s diary online

“ ur task in conjunction with the the Churchill Archives Centre, in Churchill Merchant Navies of the College, Cambridge, aims to bring Ramsay’s O United Nations, and supported by war-winning role back into the limelight. the Allied Air Forces, is to carry the Allied Ramsay’s personal archive, held Expeditionary Force to the Continent… alongside the papers of Winston Churchill, Let no one underestimate the magnitude Margaret Thatcher and others at the of this task.” Archives Centre, has been an invaluable resource for Gordon during his research for The message above was delivered by the upcoming biography on Ramsay. Admiral Sir Bertram Ramsay on 31 May, The Ramsay Archive includes his D-Day 1944. The ‘task’ was launching perhaps the diary, invasion maps, photographs and biggest amphibious invasion in the history correspondence – as well as eyewitness of warfare, the success or failure of which accounts from the Dunkirk evacuation, would likely decide the outcome of the another momentous occasion in British Second World War. Six days later, on D-Day, naval history overseen by Ramsay. after years of top-secret planning, Ramsay The collection spans his career from life was in overall command of Operation as a midshipman to D-Day and beyond, until Neptune as more than 4,000 ships and Ramsay’s untimely death in a plane crash in landing craft, nearly 200,000 men and 1945, when his aircraft crashed in France, thousands of aircraft took part in the first en route to meet Field Marshal Montgomery wave of Normandy landings. in Brussels. Seventy years on, Admiral Ramsay has become D-Day’s forgotten commander; The Churchill Archives Centre is home his pivotal role in organising what one to the papers of almost 600 important historian described as a “never surpassed political, military and scientific figures in masterpiece of planning” is largely 20th-century British history. overlooked. However, naval historian and biographer Andrew Gordon, with the help of www.chu.cam.ac.uk/archives 17 Research Horizons

Image D-Day invasion map Credit: All images the Churchill Archives Centre 18 Spotlight: Advanced materials

Image Steel’s inner strength Perforations in super bainite make the material even better at protecting armoured vehicles from projectiles 19 Research Horizons

By heat-treating steel at temperatures closer to those that are normally used for baking cakes, for 10 or more days, a new form results…

long-term collaboration between the Super bainite is strong – very strong. that of conventional monolithic rolled University and industry has resulted With a tensile strength of some 2.5 homogeneous armour,” said Brown. “By A in a super-strong form of steel, which gigapascals, just one square metre can introducing perforations into the steel, we is now being manufactured in the UK for support a weight equivalent to the weight of create a large number of edges, which use as stronger and cheaper armour for 2.5 billion apples. It has a higher density of interrupt the path of incoming projectiles.” front-line military vehicles. interfaces than any other type of metal, and Super bainite’s enormous strength makes is the world’s first bulk nanostructured metal. it ideal for these types of applications, where For thousands of years, steel has been The strength of super bainite derives not strength and toughness are paramount. In used to make or do just about whatever only from the lack of carbides, but also from addition to defence applications, there are we ask of it, from ancient suits of armour the tiny size of the iron crystals within its spin-off high-carbon alloys for which the to modern skyscrapers. It has been mass structure. Most types of steel are made up demand in Europe is up to 400,000 tonnes produced since the mid-19th century, and of very fine crystals: the smaller and finer the each year, for items such as springs, bearing global production of this most ubiquitous of crystals, the stronger the resulting steel will cages and hand tools, where hard and thin materials currently stands at more than 1.4 be. The crystals in super bainite are between sheets of steel are required. About 80% billion metric tonnes per year. 20 and 40 nanometres thick, comparable of these high-carbon steels that are being Although all steel consists primarily of iron to the width of carbon nanotubes. In manufactured in Wales are now exported to and carbon, it has an almost infinite variety of comparison, the crystals in conventional markets worldwide. properties, depending on the type or amount bainite are between 200 and 500 nanometres “In addition to its superior ballistic of other elements added to the mix, or the thick. properties, Pavise™ is manufactured in a temperature at which the steel is produced. “The size of these crystals means that far simpler way than other commercially This complexity makes steel extremely the steel is very difficult to deform, resulting available ballistic armour, and its versatile, but also very difficult to understand in a more perfect structure,” said Bhadeshia. performance comes from its unique and to design from the atomic level. “And because of the very slow cooking properties,” said Kevin Edgar, Head of Professor Harry Bhadeshia of the process, which is actually quite simple, we Marketing, Engineering Sectors at Tata Steel. Department of Materials Science and can make the steel in very large quantities at “Other armours have long lead times owing Metallurgy has spent the past three decades low cost.” to complex production routes, whereas we researching the nature of steel to develop The cooking time resulted in a product can produce this product alongside regular new alloys for a range of applications. One with highly desirable characteristics, but the production runs, which means we can react of these alloys, super bainite, has been long wait meant that super bainite was only more quickly to what the end users require licensed to Tata Steel and is currently being suitable for certain commercial applications. and work with them – this flexibility gives us manufactured in the UK by the company Supported by funding from the Engineering a real advantage.” for use as super-strong armour for military and Physical Sciences Research Council The researchers in Bhadeshia’s group vehicles, as well as for other applications. and the MoD, Dr Carlos Mateo (also from are now working with their partners in Bainite is a microstructure that forms Cambridge), Brown and Bhadeshia set out to industry to address super bainite’s main when austenite, a high-temperature phase accelerate the process. Through the use of weakness which, ironically, is its strength. of steel, is cooled to temperatures between kinetic and thermodynamic modelling, they “As it is so strong, super bainite cannot be 250 and 500°C. The structure of austenite found that by tailoring the composition of welded, so it cannot be made into very large transforms as it cools, when slender crystals super bainite and heat-treating it at slightly structures where pieces need to be joined of iron incorporate themselves into the higher temperatures, up to 250°C, it could together,” he said. “We are again working structure, and carbon compounds known as be manufactured in a matter of hours rather with MoD to further refine the structure so carbides form. The resulting bainite structure than days, without any significant loss that it can be welded, without losing the is very hard, but the carbides make it brittle in performance. characteristics that make it such a unique and prone to cracking. In 2011, super bainite was licensed to and high-performing material.” Working in collaboration with Professor Tata Steel, one of the world’s largest steel Peter Brown of the Ministry of Defence producers. Tata is now manufacturing (MoD), Bhadeshia and Dr Francisca the material at its facility at Port Talbot in Caballero in the Department of Materials South Wales, which is the first time that Science and Metallurgy set out to refine and high-carbon steel has been manufactured enhance the properties of bainite, originally on a large scale in the UK for 20 years. for use in gun barrels. It is currently available commercially for Using precise modelling, they determined civil applications such as automated teller that there is no lower limit to the temperature machines for dispensing money, and as at which bainite can be produced. By heat- super-strong armour for use on military treating it at temperatures around 200°C vehicles, under the name Pavise™. – closer to those that are normally used for Brown and his colleagues at the MoD’s baking cakes rather than for manufacturing Defence Science and Technology Laboratory steel – for 10 or more days, a new form at Porton Down determined that, counter- results: super bainite. In addition, by adding intuitively, perforations bored into super elements such as silicon and molybdenum, bainite made it even more capable of Professor Harry Bhadeshia carbides and harmful impurity phases are protecting vehicles from projectiles. [email protected] prevented from forming in the steel, reducing “The ability of perforated super bainite Department of Materials the likelihood of cracks. steel to resist projectiles is at least twice Science and Metallurgy 20 Spotlight: Advanced materials

Image Electron diffraction pattern of a thin film made of gallium nitride Credit: Wai Yuen Fu, Yucheng Zhang and Colin Humphreys

ritish manufacturer Plessey Out of the red and into Semiconductors is racing to be B the first company to make energy- efficient LEDs for home lighting at a the blue: making the LED price that consumers will pay, and they’re using a technology developed by revolution cost-effective Cambridge researchers. In 2012, Plessey acquired technology to grow a remarkable man-made material that can emit light in every part of the colour spectrum when electricity passes through it. They recommissioned a mothballed processing plant, created new jobs and hired three researchers from the University of Cambridge. Their aim: to put energy- efficient lighting within financial reach of the consumer. Prototypes of their light-emitting diodes (LEDs) rolled off the production line later that year, and by April 2013 the company was gearing up to fulfil its first commercial orders. In just 15 months, Plymouth-based Plessey had gone from never having made an LED to being the world’s first manufacturer of commercially available LEDs made on large-diameter silicon substrates. 21 Research Horizons

LEDs can last for 100,000 hours

compared with 10,000 hours for fluorescent tubes

and 1,000 hours for tungsten filament light bulbs

Today, the company is addressing a then cut into up to 150,000 pieces, each of the researchers will supply LEDs that can global market that, according to a report which forms the heart of a small LED. Using be implanted in the brain with the goal of released in 2013 by WinterGreen Research, this technology, Plessey hopes to become the mapping the activity of every neuron, to could be worth up to $42 billion by 2019. commercial leader in GaN-on-silicon LEDs, understand how the brain works both in What gives Plessey an edge over its producing billions per year. health and disease. competitors is its ability to manufacture “Growing GaN on silicon is quite a Water purification is another area where LEDs at a fraction of their costs, thanks to a complex process,” said Humphreys. A LEDs could benefit the health of millions. unique process developed by Professor Sir particular problem is the appearance of “Life on earth has developed in the absence Colin Humphreys in the Cambridge Centre for cracks on cooling from the growth conditions of deep UV and so we can kill bacteria and Gallium Nitride. of 1,000°C. This has now been solved by the viruses by damaging their DNA with deep Blue and white gallium nitride (GaN) LEDs researchers through careful balancing of the UV light,” he said. The idea is to have a ring have been commercialised around the world tension in the material as it cools down. of LEDs powered by solar cells on the inside since Shuji Nakamura in Japan developed Plessey acquired the technique when of water pipes. “We now have LEDs with the a method of growing thin GaN layers on it bought the spin-out company CamGaN, right energy level to do this, we just need to sapphire in the early 1990s. Although GaN set up by Humphreys and colleagues to increase the intensity.” LEDs are now expected to dominate the world commercialise the technology. The size of the Collaborative projects with the market for lighting, their performance and silicon wafers is greater than the conventional Universities of Glasgow and Strathclyde are cost both need to be improved. two-inch sapphire wafers, meaning a greater also investigating GaN transistors as power Humphreys’ team has developed a way of number of LEDs can be made. Fortuitously, electronics in devices that manage electrical growing GaN on the vastly cheaper substrate Plessey had a six-inch processing line that energy and LEDs as light-based Wifi (so- silicon and, crucially, a means of scaling this had been mothballed. called Li-Fi). Humphreys believes that the up for commercial purposes. “We’ve got lower “When we launched CamGaN, we were day will arrive when GaN devices will light our costs for growing GaN LEDs on silicon than contacted by companies all over the world homes, power our mobile phones, laptops, anyone else we know,” explained Humphreys. wanting to utilise the technology,” said cars and aircraft engines, and connect us “Potentially, this is an advantage that puts Humphreys. “The research has been funded wirelessly to information transmitted from Britain right at the forefront of LED research.” by government money through the Engineering traffic lights and street lights. Competition between manufacturers and Physical Sciences Research Council “In addition to the £2 billion per year (including Toshiba and Samsung) to lead the (EPSRC) and it was important to us that this in electricity savings from GaN LEDs, GaN market in competitively priced LEDs has been research be exploited here in the UK.” transistors could help the UK save £1 billion intense, driven by the increasing demand for Meanwhile, the researchers are from power electronics and 15–20% in carbon energy-efficient lights. continuing their work with what Humphreys emissions, and GaN UV LEDs could save LED bulbs have much longer working describes as a “truly remarkable” material. millions of lives,” said Humphreys. “It’s the lives than any other forms of artificial lighting: A new £1 million growth facility funded by the ultimate shopping list.” LEDs can last for 100,000 hours compared EPSRC and made by AIXTRON Ltd, a long- Plessey, in the meantime, is focusing with 10,000 hours for fluorescent tubes and term collaborator of Humphreys’ research on product improvement and reduction in 1,000 hours for tungsten filament light bulbs. group, has been installed in Cambridge, cost. “There are huge players in the market LEDs in dashboards frequently outlive the life where the researchers are adjusting minute but we were first to market with GaN-on- of the car; LED light bulbs in the home would aspects of the growth process to improve the silicon LEDs,” said Dr Keith Strickland probably have to be changed only once in a efficiency of light emission. Chief Technology Officer of Plessey. “Our person’s lifetime. The benefits of increased efficiency continuing relationship with the Cambridge LEDs also use less energy than other could go far beyond home lighting, and the research group will help us push this forms of lighting. UK homes use 20% of their researchers are now looking at applications technology to its highest potential.” energy on lighting and, because LEDs use that extend from biomedicine to power 90% less energy than incandescent bulbs, electronics. Humphreys estimates that the superior energy In collaboration with the University of efficiency of LEDs could save the UK £2 billion Manchester, they plan to build tiny LED per year in energy, and reduce CO2 emissions. devices that can be implanted by keyhole It’s little wonder that LEDs have been hailed surgery in cancer patients being treated as a lighting revolution. with radiotherapy. “If a patient moves while Yet, few homeowners have invested in an X-ray or proton beam is directed at their LEDs for home lighting. “A 48-watt equivalent tumour, then they risk healthy tissue being LED bulb costs around £15. Although it will damaged,” explained Humphreys. “An LED save people money over its lifetime, very few attached to a sensor would detect movement people will pay this. We think we can reduce at the site of the tumour in order to redirect the cost to £3,” said Humphreys. the beam.” Humphreys’ team has pioneered a Even tinier devices are being investigated technique for depositing successive layers as a means of firing single neurons in the Professor Sir Colin Humphreys of GaN and indium GaN, each only 5–10 brain. Working with US researchers involved [email protected] atoms thick and growing at the speed of in the Brain Activity Map Project – a flagship Department of Materials grass, on a six-inch silicon wafer. The wafer is initiative of the Obama administration – Science and Metallurgy 22 Spotlight: Advanced materials

Image Collagen scaffold imaged using X-ray microtomography to reveal its 3D structure; the length of the Z side of the cube is 1 mm

X Y

Body builders Credit: Jennifer Ashworth Jennifer Credit: 23 Research Horizons

iniature scaffolds made from other cells to migrate. Collectively, these scaffolds so that they encourage heart cells collagen – the ‘glue’ that holds our signals direct the scaffold to form a certain to grow. “Eventually, we hope to be able M bodies together – are being used to type of tissue or have a certain type of to use them, along with cells we’ve taken heal damaged joints, and could be used to biological response. directly from the patient, to enable the heart develop new cancer therapies or help repair “The scaffolds are a three-dimensional to heal itself following cardiac failure.” the heart after a heart attack. blank canvas – they can then be used in any Another potentially important application number of different ways,” said Cameron, for the scaffolds is in breast cancer research. It may not look like much to the naked eye, who is funded by the European Research By using them to grow mimics of breast but collagen is remarkably strong. The most Council. “They can be used to mimic the tissue, the scaffolds could help accelerate abundant protein in the animal kingdom, it way in which natural tissue behaves, or they the development of new therapies. Working gives strength and structure to skin, tendons, can be directed to form different sized or with Professor Christine Watson in the ligaments, smooth muscle tissue and many sequenced structures.” Department of Pathology, Best and Cameron other parts of the body. The technology has already gone from are fine-tuning the scaffolds so that they can Through precise manipulation at a the laboratory all the way to patients, first be used to create three-dimensional models structural level, collagen can also be used as as Chondromimetic, a product for the of breast tissue. If successful, this artificial a construction material in the laboratory or repair of damaged knee joints and bone breast tissue could assist with the screening clinic to help regenerate new tissue, repair defects associated with conditions such of new drugs for breast cancer, reduce the damaged cartilage and bone, or aid in the as osteoarthritis, trauma or surgery. By number of animals used in cancer research development of new therapies for cardiac adding calcium and phosphate to the and ultimately lead to personalised therapies. disease, blood disorders and cancer. scaffold to mimic the structure of bone, “This is a unique culture system,” said To understand these conditions better it helps regenerate bone and cartilage. Watson. “We are able to add different types and develop new treatments, or regenerate Chondromimetic has been through clinical of cells to the scaffold at different times, new tissue, researchers require models that trials and has received its CE mark, enabling which no-one else can do. Better models will very closely mimic the complex, three- its sale in Europe. make our work as cancer researchers much dimensional environments found in easier, which will ultimately benefit patients.” human tissue. Like breast tissue, blood platelets also As a natural material, collagen is ideal for require a very specific environment to grow. these biomimetic applications. By shaping Dr Cedric Ghevaert of the Department of it into porous structures, collagen acts as a Haematology is working with Best and ‘scaffold’ on which cells and tissue can grow “It could be Cameron to use the scaffold technology in three dimensions in predetermined forms, to create a bone-like niche to grow bone mimicking those found in the body. used in almost marrow cells, or megakaryocytes, for the The idea of using collagen as a scaffold is production of blood platelets from adult stem not new, but the very high level of control that any situation cells. In theory, this could be used Cambridge researchers are able to achieve to produce platelets as and when they over its properties has made a huge range where you’re trying are needed, without having to rely on of clinical applications possible, including blood donations. the repair of damaged joints or tissue, to regenerate “The technology for culturing the or accelerating the development of new cells is actually quite generic, so the range therapies for cancer. tissue” of applications it could be used for in future “There is an increasing need for is quite broad,” said Best. “In terms of clinical improved materials that work with the applications, it could be used in almost systems in the body to regenerate healthy any situation where you’re trying to tissue, rather than just replacing what’s regenerate tissue.” there with something synthetic,” said “In some senses, it can be used for Professor Ruth Cameron of the Department In future, the scaffolds could also see use anything,” added Cameron. “As you start of Materials Science and Metallurgy, as a treatment for cardiac disease. Working to create highly organised structures made who, along with Professor Serena Best, is with Professor Richard Farndale from the up of many different types of cells – such working with researchers from across the Department of Biochemistry and Dr Sanjay as the liver or pancreas – there is an ever- University to develop the scaffolds for a Sinha from the Department of Medicine, increasing complexity. But the potential of range of clinical applications. “You’re trying and supported by funding from the British this technology is huge. It could make a huge to help the body to heal itself and produce Heart Foundation, Best and Cameron are difference for researchers and patients alike.” what it needs in order to do that.” developing the scaffolds for use as patches To build the scaffolds, the researchers to repair the heart after a heart attack. begin with a solution of collagen and Heart attacks occur when there is an water and freeze it, creating ice crystals. interruption of blood to the heart, killing heart As the collagen cannot incorporate into muscle. The remaining heart muscle then ice, it gathers around the edges of the has to work harder to pump blood around the crystals. When the pressure around the ice body, which can lead to a thickening of the is dropped to very low levels, it converts heart wall and potential future heart failure. directly from a solid to vapour, leaving the By modifying the collagen scaffolds collagen structure behind. By precisely with the addition of peptide sequences, they controlling how the ice crystals grow as could be used to grow new heart cells to the water freezes, the researchers are able ‘patch’ over areas of dead muscle, to control the shape and properties of the regenerating the heart and helping it function resulting collagen scaffold. normally. Cells could be taken directly from By adding small groups of amino the patient and reprogrammed to form heart acids known as peptide sequences to the cells through stem cell techniques. Left to right surface of the scaffold at different points, While the work is still in its early stages, Professor Serena Best the way in which the collagen interacts the scaffolds could one day be an important [email protected] with the growing cells changes, altering the tool in treating coronary heart disease, which Professor Ruth Cameron potential uses for the scaffold. The peptide is the UK’s biggest killer. “These scaffolds [email protected] sequences signal certain cells to bind to the give cells a foothold,” said Farndale, who Department of Materials scaffold or to each other, while signalling is working with Sinha to characterise the Science and Metallurgy 24 Spotlight: Advanced materials

hat links legendarily sharp and from conducting polymers to diamond- Damascene swords of the past like carbon and graphene. W with flexible electronics and high- What makes carbon nanoforms such performance electrical wiring of the future? as graphene and CNTs so exciting is their They all owe their remarkable properties to electrical and thermal properties. Their different structural forms of carbon. potential use in applications such as lighter electrical wiring, thinner batteries, stronger History’s deadliest swords – the ‘Damascene’ building materials and flexible devices sabres forged in the Middle East from the could have a transformational impact on the 13th to the 18th centuries – were so sharp energy, transport and healthcare industries. they could slice through falling silk, so legend As a result, investment totalling millions of has it. Their astonishing qualities are thought pounds is now underpinning research and to have come from a combination of specific development in carbon-based research impurities in the iron ore and how hot and across the University. how long they were fired – a process that “But all of the superlatives attributed some scientists believe may have unwittingly to the materials refer to an individual, created carbon nanotubes (CNTs) atomically perfect, nanotube or graphene within them. flake,” Hofmann added. “The frequently These thin, hollow tubes are only a pictured elephant supported by a graphene single carbon atom in thickness. Like their sheet epitomises the often non-realistic carbon cousin, graphene – in which the expectations. The challenge remains to atoms lie flat, in a two-dimensional sheet achieve high quality on a large scale and at – they are among the strongest, most low cost, and to interface and integrate the lightweight and flexible materials known. materials in devices.” “Fast-forward centuries,” said Dr These are the types of challenges Stephan Hofmann from the Department that researchers in the Departments of Engineering, “and we now realise there of Engineering, Materials Science and is a whole family of these extraordinary Metallurgy, Physics and Chemistry, and the origami forms of carbon… and how to Cambridge Graphene Centre have been make them.” In fact, the University has over working towards overcoming. 25 years’ cutting-edge experience in carbon Professor Alan Windle from the nanotechnology, from diamond to nanotubes, Department of Materials Science and

6 12.0107 How C arbon Carbon 6 12.0107 C ousins shaped Carbon 6 12.0107 warfare and C an Carbon electrify the future 25 Research Horizons

Metallurgy, for instance, has been using a high-purity graphene being produced at 1 kg chemical vapour deposition process to ‘spin’ per hour. “The aim is to produce high-quality very strong and tough fibres made entirely materials that can be directly implemented of CNTs. The nanotubes form smoke in the into new devices, or used to improve other reactor but, because they are entangled and materials, like glass, metal or polymers,” elastic, fibres can be wound continuously said Koziol. out of the reactor like nano candy floss. The Working directly with industry will be yarn-like texture of the fibres gives them key to speeding up the transition from lab to extraordinary toughness and resistance to factory for new materials. Hofmann is leading cutting, making them promising alternatives a large effort to develop the manufacturing to carbon fibres or high-performance polymer and integrated processing technology for fibres like Kevlar, as well as for building CNTs, graphene and related nanomaterials, tailored fibre-reinforced polymers used in with funding from the ERC and Engineering aerospace and sports applications. and Physical Sciences Research Council It is on the electrical front that they meet (EPSRC), and in collaboration with a network their greatest challenge, as Windle explained: of industrial partners. “The process of manufacture is being “The field is at a very exciting stage,” scaled up through a Cambridge spin-out, he said, “now, not only can we ‘see’ and Q-Flo; however, electrical conductivity is the resolve their intricate structures, but you produce with the final application. Our facilities and equipment have been selected to promote alignment with industry; we have collaborations with over 20 companies who share our agenda of advancing real-life applications, and many more are discussing their involvement with our activities.” “The field is at a very exciting Cambridge has pioneered graphene engineering and technology from the very stage… we are beginning start and, with multiple spin-offs, has become a hub for graphene manufacturing and innovation. The Cambridge Graphene to understand what governs Centre aims to improve manufacturing techniques for graphene and related their growth and how they materials, as well as explore applications in the areas of energy storage and harvesting behave in industrially devices, high-frequency electronics, photonics, flexible and wearable electronics, and composites. Graphene is also the relevant environments” focus of large-scale European funding – the Graphene Flagship, a pan-European 10-year, €1 billion science and technology programme was launched in 2013. Ferrari was one of the key investigators who prepared the proposal, has led the development of the science and next grand challenge for CNT fibres in the new characterisation techniques allow technology roadmap for the project, and now laboratory. To understand and develop the us to take real-time videos of how they chairs the Flagship’s Executive Board. fibre as a replacement for copper conductors assemble, atom by atom. We are beginning Now, building work has begun on a will be world-changing, with huge benefits.” to understand what governs their growth £12.9 million bespoke facility that will host In 2013, Windle’s colleague Dr Krzysztof and how they behave in industrially relevant the Cambridge Graphene Centre, with Koziol succeeded in making electric wiring environments. This allows us to better control additional spaces for large-area electronics. made entirely from CNT fibres and developing their properties, alignment, location and The facility is due to open in late spring 2015. an alloy that can solder carbon wires to metal, interfaces with other materials, which is key “We recognise that there is still much to making it possible to incorporate CNT wires to unlocking their commercial potential.” be done before the early promise becomes into conventional circuits. The team now For high-end applications in the reality, but there are major opportunities now,” makes wires ranging from a few micrometres electronics and photonics industry, achieving said Ferrari. “We are at the beginning of a to a few millimetres in diameter at a rate of up this level of control is not just desirable journey. We do not know the final outcome, to 20 metres per minute – no small feat when but a necessity. The ability to produce but the potential of graphene and related you consider each CNT is ten thousand times carbon controllably in its many structural materials is such that it makes perfect sense narrower than a human hair. forms widens the ‘materials portfolio’ that a to put a large effort into this early on.” With funding from the Royal Society and modern engineer has at their disposal. With the European Research Council (ERC), the carbon films or structures already found in research is aimed at using CNTs to replace products such as hard drives, razor blades Professor Andrea Ferrari copper and aluminium in domestic electrical and lithium ion batteries, the industrial use of [email protected] wiring, overhead power transmission lines CNTs is becoming increasingly widespread, Cambridge Graphene Centre and aircraft. CNTs carry more current, lose driven, for instance, by the demand for new Dr Stephan Hofmann less energy in heat and do not require mineral technologies such as flexible devices and our [email protected] extraction from the earth. need to harvest, convert and store energy Department of Engineering Moreover, they can be made from more efficiently. Dr Krzysztof Koziol greenhouse gases; Koziol’s team is working Professor Andrea Ferrari, Director of the [email protected] with spin-out company FGV Cambridge Cambridge Graphene Centre and doctoral Department of Materials Nanosystems to become the world’s first training programme, which has been funded Science and Metallurgy company to produce high-grade CNTs through a £17 million grant from the EPSRC, Professor Alan Windle and graphene directly from natural gas explained: “People can now make graphene [email protected] or contaminated biogas. The company is by the tonne – it’s not an issue. The challenge Department of Materials already operating at an industrial scale, with is to match the properties of the graphene Science and Metallurgy 26 Spotlight: Advanced materials

Image Trapping the Light can be manipulated at the nanoscale, as in this elastic material which has been folded light fantastic like nano-origami

he development of a ‘nanobarrel’ that material is polystyrene or gold, changing and the permanence of their intense colour traps and concentrates light onto the shape of its nanostructure can give us make them ideal materials for security cards T single molecules could be used as a extraordinary control over how light energy and banknotes or to replace toxic dyes in the low-cost and reliable diagnostic test. is absorbed by the electrons locked inside. textile industry. We’re learning how to use this to develop “The crucial thing is that by assembling Jeremy Baumberg and his 30-strong team of new functionality.” things in the right way you get the function researchers are master manipulators of light. One of their recent achievements is to you want,” said Baumberg, who developed They are specialists in nanophotonics – the develop synthetic materials that mimic some the polymer opals with collaborators in control of how light interacts with tiny chunks of nature’s most striking colours, among Germany (at the DKI, now the Fraunhofer of matter, at scales as small as a billionth of a them the iridescent hue of opals. Naturally Institute for Structural Durability and System metre. It’s a field of physics that 20 years ago occurring opals are formed over millions of Reliability). “If the spheres are random, the was unknown. years at intense temperature and pressure, material looks white or colourless, but if At the heart of nanophotonics is the and consist of perfectly ordered glass stacked perfectly regularly you get colour. idea that changing the structure of materials spheres that diffract light. We’ve found that smearing the spheres at the scale of a few atoms can be used to ‘Polymer opals’, however, are plastic – against each other magically makes them alter not only the way light interacts with the like the polystyrene in drinking cups – and fall into regular lines and, because of the material, but also its functional properties. formed within a matter of minutes. With some chewing gum layer, when you stretch it the “The goal is to design materials with clever chemistry, the researchers have found colour changes too. really intricate architecture on a really a way of making polysterene spheres coated “It’s such a good example of small scale, so small it’s smaller than in a soft chewing-gum-like outer shell. nanotechnology – we take a transparent the wavelength of light,” said Baumberg, As these polymer opals are twisted and material, we cut it up in the right form, Professor of Nanophotonics in the stretched, ‘metallic’ blue–green colours we stack it in the right way and we get

Department of Physics. “Whether the starting ripple across their surface. Their flexibility completely new function.” Credit: Gen Kamita and Jeremy Baumberg 27 Research Horizons

Although nanophotonics is a A commonly used technique in medical self-assemble with CB at room temperature. comparatively new area of materials diagnostics is Raman spectroscopy, which Now, with funding from the Engineering research, Baumberg believes that within two detects the presence of a molecule by its and Physical Sciences Research Council, decades we will start to see nanophotonic ‘optical signature’. It measures how light is and working with companies and potential materials in anything from smart textiles to changed when it bounces off a molecule, end users (including the NHS), Baumberg buildings and food colouring to solar cells. which in turn depends on the bonds within and Scherman have begun the process of Now, one of the team’s latest discoveries the molecule. However, the machines need developing their ‘plasmonic sensors’ to test looks set to open up applications in to be very powerful to detect what can be biological fluids such as urine and tears, for medical diagnostics. quite weak effects. uses such as detecting neurotransmitters “We’re starting to learn how we can Baumberg has been working with Dr in the brain and protein incompatibilities make materials that respond optically to the Oren Scherman, Director of the Melville between mother and fetus. presence of individual molecules in biological Laboratory for Polymer Synthesis in the “At the same time, we want to fluids,” he explained. “There’s a large Department of Chemistry, on a completely understand how we can go further with demand for this. GPs would like to be able to new way to sense molecules they have the technology, from controlling chemical test the patient while they wait, rather than developed using a barrel-shaped molecular reactions happening inside the barrel, to sending samples away for clinical testing. container called cucurbituril (CB). Acting like making captured molecules inside ‘flex’ And cheap and reliable tests would benefit a tiny test tube, CB enables single molecules themselves, and detecting each of these developing countries that lack expensive to enter its barrel shape, effectively isolating modifications through colour change,” diagnostic equipment.” them from a mixture of molecules. added Baumberg. In collaboration with researchers in “The ability to look at small numbers of Spain and France, and with funding from the molecules in a sea of others has appealed European Union, Baumberg and Scherman to scientists for years. Soon we will be have found a way to detect what’s in each able to do this on an unprecedented scale: barrel using light, by combining the barrels watching in real time how molecules come with particles of gold only a few thousand together and undergo chemical reactions, atoms across. and even how they form a bond. This has “Eventually... “Shining light onto this gold–barrel huge implications for optimising catalysis mixture focuses and enhances the light in industrially relevant processes and is waves into tiny volumes of space exactly therefore at the heart of almost every product we will be able where the molecules are located,” Baumberg in our lives.” explained. “By looking at the colours of Baumberg views nanophotonics to build things the scattered light, we can work out which technology as a whole new toolbox. “The molecules are present and what they are excitement for me is the challenge of how with light itself” doing, and with very high sensitivity.” difficult the task is combined with the fact Whereas most sensing equipment that you can see that, if only you could do it, requires precise conditions that can only you can get things out that are incredible. really be achieved in the laboratory, this “At the moment we are capable of new technology has the potential to be a assembling new structures with different low-cost, reliable and rapid sensor for mass optical properties in a highly controlled way. markets. The amount of gold required for the Eventually, though, we will be able to build test is extremely small, and the gold particles things with light itself.”

Professor Jeremy Baumberg [email protected] Cavendish Laboratory, Department of Physics 28 Spotlight: Advanced materials rs pe ra c Credit: Michael Ramage Michael Credit:

Image

Seeds to Bamboo I-beam skys

ood is one of the oldest building for around 5% of total UK emissions. to create some of the most advanced and

materials but its use is limited Indeed, CO2 emissions embodied in how sustainable construction materials known.” W by its properties. With new the fabric of the building is constructed It’s a compelling vision, and one that funding, researchers aim to stretch these can be just as significant as the operational will require the combined efforts not just of properties to an unprecedented degree, emissions once it is occupied. architects and engineers, but also of plant creating the means to build a skyscraper “It’s doubtful that much can be done to biochemists, polymer chemists and experts out of plants. bring down the energy used in traditional in fluid mechanics. The ambitious five-year manufacturing of concrete and steel. project aims to “fundamentally transform the It’s not often that research begins with Primary savings will come only through way we build” and is led by Ramage from the designing a wooden 70-storey office demand reduction, including switching to Department of Architecture with £1.75 million building that falls over, at least on paper. other materials,” explained Michael Ramage, funding from the Leverhulme Trust. But this is what a group of architectural the architect behind the experimental “There are more varieties of plants engineers in Cambridge did to demonstrate wooden skyscraper. “We think there are than there are of manufactured materials,” that wood is simply not up to the task. tremendous opportunities for novel plant- added Ramage. “Although the techniques Today, almost all new large-scale based materials in construction but, as our to manipulate manufactured materials are buildings are constructed using concrete skyscraper showed, the material itself must better understood, the potential to generate and steel. Valued for their strength, be redesigned. materials with diverse properties based on flexibility and stability, these materials are “Forensic engineering showed that once plants may be far greater.” nonetheless notoriously energy-intensive, our test building reached a certain height the Plants derive much of their strength with the manufacturing of construction wood at the bottom began to crush. We want from the rigid cellulose wall that surrounds materials for buildings suggested to account to redesign wood from the molecular level each cell. What if this could be engineered 29 Research Horizons

“Although the techniques High and mighty: the new bamboo to manipulate manufactured t the World Conference on materials are better understood, Timber Engineering this A August, Michael Ramage will present research on new engineering the potential to generate materials products based on bamboo, a material that has been used to construct with diverse properties based houses for thousands of years.

As a building material, bamboo makes on plants may be far greater” great sense. It’s cheap, renewable, is found in areas of the world where structural timber is limited and it grows rs pe faster than wood. Little wonder then that new forms of laminated and resin- to have even greater strength, rather like mechanical and environmental properties impregnated bamboo are emerging as reinforcing steel bars are used to improve of naturally-based building materials. The building materials. the tensile strength of concrete? aim is to construct buildings that not only “Bamboo has captured the Team member Professor Paul Dupree use materials that have low embodied imagination of engineers and architects from the Department of Biochemistry is energy but also consume as little energy as worldwide, but its use has been limited an expert in understanding how plant cell possible when they are used. “Our ideas are largely because the material shows walls are built. Although this structure a step towards ‘living differently’,” explained variations in its geometry and structural ra forms one of the largest biomasses on Ramage. “It’s a vision that can only be properties,” explained Ramage. “Full Earth, many fundamental aspects of its achieved by strong multi-disciplinary acceptance of these materials has been structure and function, and the enzymes connectivity.” hindered by a lack of engineering data responsible for its synthesis, have largely The research programme fuses

c been a mystery. Dupree’s work focuses on fundamental and applied sciences, and is improving the efficiency of using plants as firmly connected with industrial applications. biofuels by determining how to release the Team member Dr Beatrix Schlarb-Ridley, myriad of sugars locked into the cell wall. By along with Dr Brenda Parker in the “Bamboo has deciphering how to unbuild cell walls, he is Department of Plant Sciences, supports also gaining understanding of how they can companies in the East of England in taking captured the be built better. Ultimately, the researchers up low-carbon solutions based on plant would like to understand the process materials as part of the InCrops Project. The imagination enough to be able to breed or genetically researchers hope that this interaction will engineer plants that are naturally stronger. provide a continuous flow of practical ideas of engineers Meanwhile, pioneering work by Ramage into the project and facilitate the transfer of and Dr Oren Scherman, in the Department new technologies into industry. and architects of Chemistry, is looking at boosting the “Effectively we are working from micro strength, stiffness and longevity of plant- to mega,” summed up Ramage. “We want worldwide” based materials by impregnating them with to redesign natural materials to carry out polymers. Their aim is to use low-value, different functions that will change the fast-growing species like spruce and way we construct cities. This starts at the

skys bamboo (see panel) in tall buildings. For molecular level and continues to engineered instance, they have shown that impregnation solutions to sustainable living. Our work will on which regulatory bodies can base of spruce by soaking in methacrylate, a show a way for improved natural materials building standards.” polymer commonly used in windscreen that are better for people, and better for With funding from the Engineering repair kits, can increase spruce’s strength the planet.” and Physical Sciences Research and resistance to fungal attack. And as the project nears completion, Council, Ramage and colleagues have This technology could be used to Ramage and colleagues aim to return to been investigating the properties of construct polymer-modified wooden beams their plans for a 70-storey skyscraper bamboo products. He has been working that are stronger at the ends for better made of wood, and show this time that it with the independent consultancy connections, and stiffer in the middle for can work. Cambridge Architectural Research greater spans. Scherman, Ramage and Limited, and in collaboration with the Dupree will work together to understand Massachusetts Institute of Technology where the polymers end up in the plant cell and the University of British Colombia. and what this means for improving structural Their preliminary results have properties. shown that some mechanical properties And it’s not just structural construction were similar to those of timber (such materials that the researchers have in mind. as stiffness), but others, like tensile They hope to uncover a range of uses and strength, are up to five times greater. scales of modified natural materials that This suggests that bamboo might even improve the sustainability of the way we be used to replace steel eventually, live, including new materials that moderate as Ramage explained: “We think that temperature and humidity in buildings. with some slightly more advanced The expertise of Professor Paul engineering we can reconstitute Linden from the Department of Applied bamboo into shapes like the rolled steel Mathematics and Theoretical Physics will joists, or I-beams, used in buildings. be crucial for this – his group develops Michael Ramage The time has come to exploit bamboo to models of the fluid flow in low-energy [email protected] its full potential as a durable, strong and buildings, which will be used to optimise the Department of Architecture beautiful material.” 30 Spotlight: Advanced materials

erovskite materials are the newest efficient at absorbing photons of light and ‘snapshots’ a few quadrillionths of contender for breaking the silicon that this can be converted into an electric a second apart. P ceiling in solar cell technology. But current in photovoltaic solar cells. As PhD student Michael Price described: they don’t just absorb light. Cambridge A defining moment came in 2012, when “This enables us to monitor directly what is researchers have found they emit it like a Professors Henry Snaith at the University of happening to the electrons, which generate laser, opening up an entirely new field Oxford and Michael Graetzel at the Federal the current in the material – where the of applications. Institute of Technology Lausanne, building excitations are and how they are destroyed, on the work of Tsotomu Mayasaka from essentially how fast they live and die.” Discovered 175 years ago in Russia’s Tokyo, found that solar cells with perovskite In collaboration with Snaith’s group mineral treasure box – the Ural Mountains – as the active component could be made in Oxford, the scientists are using and named after the mineralogist Count Lev with greater than 10% power conversion this fundamental insight to help them Aleksevich von Perovski, perovskite is fast efficiencies for turning the sun’s rays into understand how the efficiency of perovskite- becoming a ‘rock’ to be reckoned with. In electrical energy. A mere two years later, based photovoltaics might be extended 2013, the use of perovskite materials in solar Snaith increased this to 17%. For silicon- yet further. cells was voted as one of the breakthroughs based solar cells, it’s taken 20 years of The lasing properties (published in the of the year by Science magazine; more research to achieve this level. Journal of Physical Chemistry Letters in recently, the Guardian website declared Now, researchers in Cambridge have March) were discovered when Friend’s team that they “are the clean tech material found another property of this remarkable measured the photoluminescence efficiency development to watch right now.” material – it doesn’t just absorb light, it also of the material, and found that up to 70% Perovskite is a term used to describe emits it as a laser. of absorbed photons were emitted under a group of materials that have a distinctive Led by Professor Sir Richard Friend the right conditions. This led to the idea of crystal structure of cuboid and diamond from the Department of Physics, the sandwiching a thin layer of the lead halide shapes. They have long been of interest researchers have been investigating how perovskite between two mirrors to create an for their superconducting and ferroelectric perovskites work by exciting the material optically driven laser. properties. But, in the past five years, it was with light and monitoring energy absorption “It turns out that perovskites are discovered that they are also remarkably at incredibly fast timescales, taking remarkably fluorescent materials,” explained

Light in, light out: the ‘rock’ that breaks the rules

Image Laser using a ‘perovskite’ organic metal halide material Credit: Michael Price, Felix Deschler and Richard Friend 31 Research Horizons

Friend. This is not in itself a surprise – since Intriguingly, early results show that the early 1960s a relationship between the the material doesn’t appear to work in the generation of electrical charges following way that might be expected. “For me, the light absorbtion and the process of excitement is that these materials break the ‘recombination’ of these charges to emit light rules,” said Friend. “Many of their properties has been known. “But these materials do are somewhere between those of an organic so very efficiently,” said Friend. “It’s unusual and an inorganic semiconductor. The way The lasing properties in a material that is so simply and cheaply we make them, they should have too many prepared.” chemical and structural defects to work as were discovered when “Mix and squirt,” is how Price described well as they do and yet they are as efficient the preparation process: “we make a solution as purified silicon, which is a single crystal.” Friend’s team measured of the halide perovskites and spin- coat Would they be better if cleaned up? them onto an electrode. There’s no need for “Possibly,” said Friend, “but we want to have the photoluminescence elaborate purification.” This simple process, our cake and eat it. We want the efficiencies which the scientists say is scalable, is in and the ease of preparation.” efficiency of the material, contrast to the painstaking growth of crystals Defects in materials normally cause needed for other solar cell materials like charged electrons to get ‘stuck’ and lose and found that up to 70% silicon to ensure that the number of defects their energy. One possibility for perovskites in the materials is kept as low as possible. might be that the defects don’t matter of absorbed photons “Perovskites are cheap and abundant, because the material has the capacity to they are easily fabricated and they have ‘self-heal’. were emitted a high efficiency of energy conversion – “There’s something going on... these these three together are the holy grail of materials have a tolerance to disorder photovoltaics, which is why there is such which is unusual,” explained Friend. “It’s excitement about them at the moment,” speculation, but perhaps the material can fill added Dr Felix Deschler. defects on the fly. The way the material

The lasing properties of perovskites is prepared creates a lot of free ions, and “This feels like it’s the dawn of a new raise expectations for even higher solar cell these might move around and fill up defects. field,” said Friend. “So far we’ve looked at the efficiencies, as Friend explained: “There’s a Imagine a bumpy road with potholes – the materials as they are. The question now is fundamental relationship between how good ions might fill the potholes and then the how good will they be?” a material is at emitting light and how well it electrons have a smooth ride.” works in a solar cell.” A better understanding of these www.winton.phy.cam.ac.uk The team’s work is based on a processes will feed into the collaboration programme of research on organic (i.e. with Snaith’s group, helping the scale-up and carbon-containing) semiconductors that has commercial deployment of perovskite-based spanned over 20 years in Friend’s laboratory, photovoltaics through the Oxford spin-out most recently as part of the Winton Oxford Photovoltaics. Programme for the Physics of Sustainability, Meanwhile, the Cambridge team is and has resulted in the development also pursuing the material’s light-emitting of roll-to-roll printing of photovoltaic properties, as Deschler explained: “It opens materials, light-emitting diodes (LEDs) and up a completely new field of applications. printed transistors for paper displays. The The laser industry is huge – they are used in techniques Friend’s group has developed for areas that are critical for our lives, including characterising organic semiconductors are telecommunications, medicine and industry. now being deployed on the mostly inorganic We think there will be applications for perovskite materials. perovskites that extend far beyond the The current focus is on identifying the solar cell.” fundamental mechanisms that are at play In particular, the researchers are Left to right when photons of light raise electrons in the now looking at applying the high Michael Price material to higher energy states, and on luminescence efficiency to create light- Dr Felix Deschler looking at precisely how and where energy emitting diodes. Other members in the Professor Sir Richard Friend losses occur – an understanding of which research group have already had some very [email protected] will be crucial to maximising the efficiency promising results in this area, which should Cavendish Laboratory, of these light-harvesting solar cells. be published soon. Department of Physics 32 Spotlight: Advanced materials

The atomic The ability to building site control atoms as if they were billiard balls is required to make the next generation of advanced materials possible

he ability to design, control and build However, it’s extremely difficult to new materials at the level of individual control the growth of complex oxides at the T atoms could open up a whole new atomic level. To achieve this, new methods world of electronic devices. of laying down atoms need to be found, and any defects in the materials need to be Making a perfectly flat layer of billiard balls is minimised or eliminated. fairly straightforward. Doing the same thing Defects influence the electronic with atoms is rather more difficult. But as properties of a material. In conventional we demand more of materials, the ability to electronic devices, information is carried via control atoms as if they were billiard balls the charge or spin on electrons, so anything is required to make the next generation of Oxides are prime candidates for making interfering with the electrons will affect the advanced materials possible. these new applications possible. Complex material’s performance. Atoms located in Researchers in Cambridge are bringing oxides – compounds of oxygen and one the wrong place or missing entirely can these ‘made-to-measure’ materials one step or more metallic elements – potentially snare electrons like a mouse in a trap. The closer to practical applications, and soon they have new properties that surpass those number of defects that can be tolerated will do so at unprecedented levels, thanks to of silicon-based electronics. These make varies depending on the application. a new pulsed laser deposition (PLD) system them ideal for next-generation computing Semiconductors, for instance, need to – unique in the UK – that allows for atom-by- devices that process vast amounts of data be as close to perfection as possible: the atom design and growth. in an energy-efficient way. maximum amount of imperfection that 33 Research Horizons

can be tolerated is roughly equivalent to a Blamire explained: “Sputtering is a very Manufacturing with ultra precision pinhead on a football pitch. flexible and accurate technique for many “Designing and growing new materials types of metals, but it is not particularly at the atomic scale are not yet ‘made- well-suited to single-crystal oxide thin films. Developing advanced materials is only to-measure’ processes,” said Professor We have invested heavily in pulsed laser part of the journey that leads to new Judith Driscoll of the Department of deposition, but the thickness control and technologies. Manufacturing companies Materials Science and Metallurgy, who the range of materials which can be grown also need to make them with ultra specialises in fine-tuning the properties of is still limited.” precision. oxides for applications in energy, low- Now, Driscoll, along with colleagues energy electronics and photovoltaics. in Materials Science and the Department The next generation of smart phones The properties of oxide materials can be of Physics, has secured funding from the might monitor your heart rate, measure manipulated by changing the bond lengths University and the Engineering and Physical the alcohol in your blood or give you or angles between atoms, but cost- Sciences Research Council for state-of- a complete checkup by analysing the effectively designing them to be as close to the-art new PLD equipment that will make chemistry of your sweat. These ‘personal perfect as possible is not easy. ‘made-to-measure’ materials possible. assistants’ will have an array of embedded The new system uses advanced PLD with miniature sensors and processors reflective high-energy electron diffraction derived from the latest breakthroughs to control growth rate and produce single in microelectromechanical systems atomic layers with a minimum of defects. technology. The technique will give researchers the But to make devices like these capability to measure thin-film thicknesses requires extraordinary levels of precision with extremely high levels of accuracy – the ability to manufacture intricate – down to less than one nanometre in features that are smaller than thickness – as well as the ability to perform 100 nanometres. in situ chemical analysis to ensure the Diagnostic smartphones are just one materials and the surfaces they are creating example of the new kinds of products have the intended chemical and electronic that are going to need ultra precision structures. manufacturing. The emergence of polymer “In addition to helping us build really or carbon-based materials like graphene useful things from oxides, this new is driving research and development in technology will help us to discover and areas such as the production of lower explore the properties of new materials,” cost, more-efficient solar cells and added Driscoll. “It will take some long-term ‘printed electronics’ that can be used thinking to see them transition to practical for flexible display screens and smart “Over the past 15 years, we’ve made applications, but once we achieve control labelling. huge advances with making materials over these materials at the atomic scale, the “For these devices to become reality, perfect at nanometre-length scales, but we practical applications will follow. We believe companies are going to need a whole new still can’t easily understand things going on that such oxides could really revolutionise set of production capabilities,” explained at the atomic scale. You assume that things electronics.” Professor Bill O’Neill at Cambridge’s are perfect, but in reality they are not, and Institute for Manufacturing (IfM), in the you don’t know by how much – you can only Department of Engineering. The ultra infer it from indirect measurements. To make precision research his team carry out really perfect structures, you have to be at the IfM is focused on building these able to control the number of atoms being kinds of machines and developing the deposited and to stop at the exact point that associated systems and processes that a single complete layer has been grown.” can make things at nano levels of precision. Most metal oxides are grown using In 2011, the Engineering and Physical thin-film deposition techniques, where Sciences Research Council awarded atomic layers are built one on top of the £6 million to the Centre for Innovative other on a substrate. Thin-film techniques Manufacturing in Ultra Precision, a are used by several Cambridge research joint venture between the University of groups who are interested in the physics Cambridge and Cranfield University. and chemistry of functional materials, and “Cranfield has decades of experience how they can be manipulated. For instance, of designing machines, including some in the Department of Physics, researchers of the most precise machine tools in the are using these techniques to explore the world,” he said. “By virtue of the extensive quantum properties of semiconductors. In materials research taking place across the Materials Science, Professor Neil Mathur’s University, we have experience of working group uses thin films to study the electrical with the new generation of unconventional and magnetic properties of materials, for semiconductor materials. The partnership example attempting to control either their with Cranfield coupled with the cross- temperature or their magnetism through Cambridge collaborations creates a very voltage; and Professor Mark Blamire’s strong team with the potential to transform group is using them to create new kinds of the way we think about and make the next magnetic and superconducting devices. generation of products. While thin-film techniques such as “The endgame for us is to provide ‘sputtering’ (eroding material from a source industry with a wide range of experts in onto a substrate) have been vital in getting various disciplines that are centred around advanced materials such as metal oxides the design, development and production to their current state, they do not provide Professor Judith Driscoll of ultra precision products either the level of control that’s needed to [email protected] and processes.” see them used in practical applications nor Department of Materials the capabilities to make them at scale, as Science and Metallurgy Feature article available online 34 Inside out: Julia Gottschalk

Extreme sleepover: All aboard the floating science factory

eep sea sediment cores – they’re and a stop in Spain to load geophysical cold, they’re muddy, and they’re equipment, we have made our way to our D revealing 30,000 years of climate working area – the continental margin history – as PhD student Julia Gottschalk off Portugal. reports from her voyage aboard the James It’s an extraordinary region for the Cook research ship last summer. study of past ocean chemistry and climate dynamics. Sea floor sediments capture the The vast and enigmatic ocean covers ocean’s history because the nature and the about three quarters of the Earth, yet the chemical composition of particles settling to information we have from its depths is the sea floor varied as the atmospheric and comparable with the distribution and size of oceanic circulation changed over time. the holes on a golf course. The pioneering work of Cambridge I am waking up at sea. It is 7.50am. palaeoclimatologist Professor Sir In 10 minutes, my daily shift on our Nicholas Shackleton showed that these oceanographic expedition will start and I sediments record climate signals from the had better be on deck. North Atlantic and the Southern Ocean. The James Cook, a British Royal The discovery of interhemispherically Research Ship operated by the Natural linked climate changes recorded by tiny Environment Research Council and the microfossils the size of sugar grains National Oceanographic Centre, left preserved in sea floor sediments at a single I see a bright-blue Southampton about three weeks ago. site was a milestone in the field. Aboard with me are 26 scientists from I’m here as part of my PhD research with sea, glittering like silk Cambridge, Zurich, Lisbon, Barcelona and Dr Luke Skinner and Professor David Hodell, Bremen, plus crew. After rough seas in the and our mission is to continue Shackleton’s as the sun begins to Bay of Biscay, an escort of dolphins legacy by studying climate history further rise... and the arrival back in time and in more detail. The geophysical-acoustic imaging of of the box corer Iberian margin sediment below the sea floor, one of the objectives of this voyage, was finished several days ago and sediment coring operations have started – or as our geophysicist colleagues call it – playing with mud! It is very hard to get up from my berth. The topmost sediment reflects modern A quick look out of the porthole... it doesn’t conditions and can therefore be used for look like a washing machine, it will be a calibrations. The sediments are extremely calm day at sea. Making my way to the cold. It’s 2°C at that depth, quite a contrast ship’s working deck and jumping into my to the air temperature of 23°C today. already mud-covered overall, I discuss with We hand subsamples over to the micro- Natalia from the ‘four-to-eight’ shift what I sensor measurement and water chemistry can expect during my shift. groups who work in specialised labs on Stepping out onto the deck, I see a the ship while we continue sampling for bright-blue sea, glittering like silk as the later analyses. Other scientists prepare sun begins to rise... and the arrival of the new water sample measurements and add box corer, a 40 by 40 cm steel box that chemicals to the sampled sediments, the carves into the sediment to sample a chunk deck crew prepares the deployment of the of sea floor mud and ideally some bottom next coring device, the bridge plans the water from just above the sea floor. As we route to the next station, the geophysicists look at the newly retrieved box core we analyse data, and the kitchen crew prepares are impressed by the chunk of original sea another delicious meal… we are a floating floor that rose from 4 km below the point science factory at 10°W, 37.5°N on the we are standing now. Charly, my shift-mate, Atlantic Ocean. and I invent names for the tube worms and The digital screen showing data from the some gastropods we see, and then start to winch indicates 10 minutes to the retrieval of subsample and scrape off the surface of mud. the kasten corer. This long, steel 35 Research Horizons

Bolt by bolt, we open the lid of the barrel – the moment of revelation

container penetrates the sediment to much greater depths than the box corer. The deck crew lay the kasten corer horizontally down on the deck for us with a crane and after disassembling the 6-metre-long core barrel, bolt by bolt, we open the lid of the barrel – the moment of revelation. How much has been sampled? What does the sediment look like? We get a beautiful view of 4 m of original Iberian margin sediments – about 30,000 years of climate history. The changes in colour document the oxygen-rich, bright sediment full of tiny fossils of marine plankton that thrived in the oceans of the past 10,000 years. We even find a fossil coral. Sediments formed during the last ice age, when the oceans were much cooler, are usually much darker, which suggests that ocean circulation and ecosystems were very different. Everybody is excited about the new samples. Many hands are needed to process the bulky kasten core but this will yield enough study material for a range of different analyses. By the end of our five-week-long cruise, we will have sampled 166 m of ocean sediment, analysed 1,000 water samples, seismically imaged the sea floor along a track 755 km long and studied 47,000 litres of ocean water. The ocean remains big and mysterious but we are getting closer to its secrets day by day.

Audio slideshow available online

Julia Gottschalk [email protected] Department of Earth Sciences T +44 (0)1223 765 443 Contact E [email protected] Research Horizons W www.cam.ac.uk/research Office of External Affairs and Communications f www.facebook.com/cambridge.university The Pitt Building, Trumpington Street www.twitter.com/cambridge_uni Cambridge, CB2 1RP www.youtube.com/cambridgeuniversity Cover Electron diffraction pattern of a thin film made of gallium nitride, one of the advanced materials we focus on in this issue. Find out more on p. 20. Credit: Yucheng Wai Fu, Yuen Zhang and Colin Humphreys