Cambridge’s Science Magazine produced by
Issue 10 Michaelmas 2007
in association with
www.bluesci.org
The Large Hadron Collider Europe’s £5 billion experiment
Mining the Moon An unexpected fuel source
Sea Monsters In the wake of the giant squid
Extremes of Pain • Ruby Hunting • Science Blogging The Matangini Project • The Government’s Chief Scientific Advisor
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Issue 10
Michaelmas 2007
contents
Features Squeaky Clean
12
Gillian Brodie investigates what has gone wrong with our immune system..............................
In the Wake of the Giant Squid
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James Bullock explores the underwater world of sea monsters.............................................................
Mining the Moon
16
Michaela Freeland explores a far-reaching project to replace fossil fuels...................................
Stem Cells and Cancer
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Brynn Kvinlaug reveals the role of stem cells in cancer..................................................................................
Extremes of Pain
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Alexandra Lopes explores the science behind feeling pain............................................................
How Green is Your Lab? Dr Joanna Baxter finds out what fellow scientists can do to keep Cambridge green...........
Regulars
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Editorial .............................................................................................................................. 03 Focus ................................................................................................................................... 04 Book Reviews ................................................................................................................... 11 A Day in the Life of ......................................................................................................... 22 Away from the Bench ..................................................................................................... 24 Initiatives ............................................................................................................................ 25 History ............................................................................................................................... 26 Arts and Reviews ............................................................................................................. 28 In Brief ................................................................................................................................ 30 On the Cover ................................................................................................................... 31 Dr Hypothesis .................................................................................................................. 32
BlueSci Film Team is offering ideal opportunities for people interested in producing, filming and directing science-related films and podcasts. No experience is necessary and training will be provided. Get involved as a project editor or as a general member to work on short film projects, news interviews for the BlueSci website and podcasts, from conception to filming and post-production with industry standard software. You will be free to take on as much or as little as your free time and enthusiasm allow, but whatever you do put in is guaranteed to be enjoyable and worthwhile. Whether filming or podcasting are your hobby, or you are considering a career in the media, BlueSci is highly respected in the science media industry for its quality output and has alumni working presently at Nature and New Scientist magazines and the BBC, among many other outlets. For further information on how to get involved contact: Head of BlueSci Film, Chloe Stockford (cas84@cam.ac.uk)
Kelly Neaves
From The Editor Welcome to the tenth issue of BlueSci! Within the following pages, you will find a host of entertaining and informative articles; our editorial aim has been to include a wide range of scientific topics, and to make them comprehensible to all. Our agenda includes more serious issues, too. The ARTS AND REVIEWS article discusses the dissemination of knowledge via blogs. Whilst publishing scientific material that has not been peer reviewed remains controversial, it is gaining in popularity. For example, Nature Precedings was recently established by Nature Publishing Group as an online forum for presenting preliminary findings and opinion. This theme is extended in A DAY IN THE LIFE OF... where the Chief Scientific Advisor to HM Government discusses journalistic and editorial responsibility. In a climate where we are so frequently exposed to scare-mongering and scandal, it can be difficult to know what to believe—
but Professor King’s message is clear: “Science can inform!” Whilst Professor King gives a run-down of what the big issues facing the world are (in relation to climate change, he has suggested that as many as three billion lives hang on 3ºC), our HISTORY article trains its lens on the other side of the stratosphere, and tells the story of Cambridge’s role in elucidate the structure of the cosmos. Our FOCUS article takes us from the incomprehensibly vast to the vanishingly small: it tells how £5 billion is being spent on a single experiment to explode subatomic particles—an experiment that may explain phenomena such as gravity and mass. The tale is extraordinary, highly readable, and clear detail is provided for the aficionados in the text boxes. Go on—take a dip into the world of particle physics! Terry John Evans issue-editor@bluesci.org
Lorina Naci
From The Managing Editor Welcome to the new issue of BlueSci! Many thanks to everybody in the CUSP team for their hard work that made this issue possible, and to Varsity for its continued support. As Cambridge’s leading popular science magazine run by students and postdocs, BlueSci brings to you the latest cutting-edge scientific research. Central to BlueSci’s raison d’etre is the democratization of access to scientific inquiry via transparent and interactive reporting. Our Film Team travelled to CERN—the world’s largest particle physics laboratory—to find out why smashing protons moving at 99.9% the speed of light, in a 27 kilometre-wide underground tunnel, may help us understand the beginning of our Universe. We hope you will join us and become involved in debating and communicating science within Cambridge and beyond.
This Michaelmas, BlueSci’s past members and other professionals working in science media will offer weekly workshops in popular science writing, photography, filming, podcasting, online publishing, web development and careers in media. If you’d like to take advantage of these training opportunities or to become part of BlueSci, be it with writing, illustrating, graphics, or production please do not hesitate to get in touch with us at enquiries@bluesci.org. To check out our CERN movie and for other complimentary material to the printed edition of BlueSci, as well as weekly news, podcasts and videos of high-impact Cambridge science events don’t forget to visit www.bluesci.org. Please do let us know what you think. Lorina Naci managing-editor@bluesci.org
Next Issue: 18 January 2008 Submissions Deadline: 30 October 2007
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Issue 10: Michaelmas 2007 Published by Varsity Publications Ltd Editor: Terry John Evans Managing Editor: Lorina Naci Production Manager: Lara Moss Pictures Editor: Kelly Neaves Submissions Editor: Maya Tzur Publicity Officer: Collette Johnson In Brief Team: Beth Ashbridge, Subhajyoti De, Thomas Kluyver, Michelle Percharde, Book Review Editors: Margaret Olszewski,Tom Walters Focus Editor: Tristan Farrow Focus Team: Amy Chesterton, Michaela Freeland, Alexandra Lopes, Chloe Stockford Features Editors: Chris Adriaanse, Beth Ashbridge, Peter Basile, Miriam Ferrer, Michaela Freeland, Lara Moss, Michelle Percharde A Day in the Life of... Editor: Chloe Stockford Away from the Bench Editor: Matthew Yip Initiatives Editor: Lara Moss History Editor: Jonathan Zwart Arts and Reviews Editor: Mico Tatalovic Dr Hypothesis: Mike Kenning, Rob Young Second Editors: Tamara Evans Braun, Amy Chesterton, Kevin Dingwell, Juliette Gray, Alexandra Lopes, Matthew Yip Copy Editors: Peter Davenport, Lara Moss, Lorina Naci Production Team: Jon Heras, Lara Moss, Kelly Neaves Pictures Team: Sonia Aguera, Jon Heras, Kelly Neaves, Adam Moughton,Tom Walters, Richard Ward, Catherine Williams, Sanne de Wit CUSP Chairman: Steven Ortega ISSN 1748–6920
Varsity Publications Ltd Old Examination Hall Free School Lane Cambridge, CB2 3RF Tel: 01223 337575 www.varsity.co.uk business@varsity.co.uk BlueSci is published by Varsity Publications Ltd and printed by Warners (Midlands) plc. All copyright is the exclusive property of Varsity Publications Ltd. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, without the prior permission of the publisher.
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Deep underground, beneath the border between France and Switzerland, thousands of physicists and engineers are busy putting the finishing touches to a machine so complex and so large that you could fit London Underground’s Circle Line into it, tunnel and train. Housed at CERN, the European particle accelerator facility, it is called the Large Hadron Collider (LHC), and is the most powerful particle accelerator ever built. Seven times more powerful than anything that has gone before, it will accelerate protons—particles that together with neutrons compose atomic nuclei—very close to the speed of light before smashing them together. Using a sledgehammer to crack a nut doesn’t quite do justice to the violence of the collisions. The energies are so large that scientists hope to re-create conditions present in the Big Bang, which exploded our Universe into existence about 14 billion years ago. And the aim? Why, no less than to solve some of the deepest mysteries man ever pondered: where do mass and gravity come from? Are there more than three dimensions of space? Is most of our Universe made up of a different kind of matter that is invisible? The LHC is due to be switched on next year, but it will take months, if not years, before physicists learn to drive the machine and tune it to full power.Yet, the timing of the inauguration couldn’t be better. Europe celebrated its Golden Jubilee this year, and what present other than the LHC could better celebrate what co-operation can achieve? “The LHC is an enterprise that shows European collaboration at its best,” says Sir Martin Rees, Master of Trinity College, Cambridge, and President of the Royal Society.“It will ensure that Europe retains a world lead in particle physics for at least the next decade.” With a price tag of £5 billion (half the building cost of the Channel Tunnel), the LHC is a birthday present on a scale that would have made pharaohs blush. But the collaborative nature of the project costs the UK a more modest £70 million each year. Still, it is no wonder that many in the scientific community are nervous at the prospect that the machine may well
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Scientists hope to re-create conditions of the Big Bang
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fail to make any radical discoveries, or, woe betide, that the veteran of US particle physics, the Fermilab Tevatron particle accelerator in Chicago, might get there first, following an upgrade to whip a final drop of power out of the old workhorse. The race is now on.
04
When Science Cau
Our Focus team explores the Large Hadron Collide You could be forgiven for thinking that what follows is an extract from a of befogging the intuition of the tidiest minds, so readers are urged to leave in Wonderland may seem rather dull as you read through the next few “Particle physics is a science that’s highly capital intensive,” argues Rees, “and the best strategy to make progress is to put most of the money into one huge instrument. When the history of science in these decades is written, then the deeper understanding of fundamental particles will be one of the most important chapters—by any criterion of importance and interest it will be more than two percent of the story. We in the UK are spending rather less than two percent of our public budget for our participation in the LHC, and I think that’s entirely appropriate.” But a high price tag naturally attracts high expectations.Yet the basic fact about science remains: research can often be at best an informed shot in the dark. The last missing piece of evidence in the Standard Model—the theory that classifies
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particles into a neat botanical garden of the building blocks of the Universe—is the Higgs boson. Theorists predict that the mysterious particle gives mass to other particles, including us, by producing a treacle-like field through which it is hard to move. But some particles, like photons, don’t feel that field, which would explain why nothing can travel faster than light. Until the LHC manages to detect the Higgs, the particle will remain a convenient postulate to get around a mathematical problem in the Standard Model, but without it, the Model unravels. Finding the Higgs is the benchmark by which the LHC will be judged, and to which the entire project was pegged and ‘sold’ to policy makers. Perversely, should the existence of the Higgs particle be contradicted by findings made at CERN, many
Michaelmas 2007
uin
ox
G rap hic sa nd Ke lly N
eav es
ght up with Fiction
er, one of the world’s largest scientific experiments science fiction novel. Modern physics now has a well-established tradition behind their workaday common sense at the end of this paragraph. Alice pages. would relish the prospect of re-writing or refining a theory that was thought complete, much like Newton’s laws of mechanics were eventually overtaken by Einstein’s theory of relativity. The LHC is actually the collective name given to four principle particle detectors threaded together by a 27 kilometre-long ring tunnel. The protons are accelerated by thousands of superconducting magnets along the tunnel in two beams rotating in opposite directions and are brought together inside the detectors to produce head-on collisions.The beams themselves are pumped through a pipe no wider than a 20 pence coin, but at full power, each beam bristles with as much energy as a 200,000 tonne supertanker steaming at 20 miles per hour. Inhabitants of nearby Geneva can be reassured that if some of the particles
www.bluesci.org
don’t make the bends, the hard Alpine bedrock will obligingly offer itself up for instantaneous vaporisation. But building underground wasn’t only a safety measure—in a hilly region, it is the only place that might offer a flat location sheltered from vibrations. Brian Cox, a key worker on the ATLAS detector who recently starred in the BBC’s Horizon programme about the LHC, likes to retell the happy anecdote of the mysterious vibrations in the tunnel. Engineers were puzzled for months on end by tiny periodic vibrations, until that is, they realised by consulting the French railway timetable that the periodicity of the mystery corresponded exactly to the passage of a TGV train nearby. One cannot help but feel sympathy for poor UK-based physicists who would stand no chance of solving that one.
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Eq
In the jargon, each proton in the beam has an energy of seven teraelectronvolts (TeV). That’s equivalent to the energy of a mosquito in flight. An underwhelming statistic maybe, but not when you consider that all the energy is concentrated into a volume astronomically small compared to the gargantuan mosquito. So when two protons collide head-on 14 TeV of energy will be released into a vanishingly small volume. With the odds of that collision being 1 in 10 billion, producing them at all is quite an art.The particles are so small that it would be next to impossible to engineer the knocking together of two individual protons. But brute force offers a way around this: inject into each beam literally trillions of protons travelling in 20 centimetre-long bunches with 120 billion protons each and crossing every 25 nanoseconds, and your odds are dramatically improved. In the best-case scenario, physicists expect up to 35 collisions each second. The largest detector at the LHC, ATLAS, sits in a vast cavern that could house London’s St Paul’s Cathedral. Its smaller brother, the Compact Muon Solenoid (CMS), contains more iron than the Eiffel Tower and weighs 12,500 tonnes—more than 30 jumbo jets—in order to produce the huge magnetic field needed to bend the flight path of particles whizzing through it at high speed. Particle detectors are essentially giant digital cameras that take snapshots of collision products as they fly apart.They have an onion layer-like structure, where each layer specialises in the detection of a different particle species. Particle physicists are science’s answer to bush trackers, spending their time identifying the unique footprints left behind by different particles. “Both ATLAS and CMS are general purpose detectors, but they adopt a very different design to tackle the same problem [of finding the Higgs],” says Geoff Hall, who leads the CMS team of Imperial College London. “Unlike CMS, which has a traditional cylindrical shape, the magnetic field created by ATLAS is the shape of a toroid—a doughnut.” Hall’s team plays a major role in developing high-speed electronics for the core of the
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Particle physicists are science's answer to bush trackers
CMS. “A
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big challenge was to make sure that it could withstand a very hostile radiation environment not found anywhere on earth except in the centre of nuclear reactors.” Another detector, dubbed ALICE, will perform perhaps the more bizarre exper-
05
Focus
iment at CERN, according to Mark Lancaster from University College London, who is helping to develop the ‘Grid’—a worldwide network of interconnected computers that will crunch through the deluge of data from the LHC.“ALICE will study quark-gluon plasmas,” explains Lancaster. “That’s the primordial particle soup present in the early Universe that coalesced into bigger particles and the building blocks of galaxies.” The choice to smash protons together is only second-best, because in the world of elementary particle physics, protons are akin to flying rubbish bins. When they collide, particle physicists must sift painstakingly through untold amounts of
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In the world of elementary particle physics, protons are akin to flying rubbish bins
debris to find the particles that matter, such as the Higgs. Life would be so much easier if only they could collide simple particles such as electrons instead. Unlike protons, electrons are fundamental particles with a simple internal structure.That makes the collisions much easier to study. Ironically, in its previous incarnation ten years ago, the tunnel at CERN housed an electron accelerator, the LEP (Large Electron Positron collider). But the Achilles’ Heel of that machine was a law of physics that requires very light
CERN Press & Media
particles moving in a circle to lose energy by radiation, so-called synchrotron radiation. This by-product of particle physics is so useful nowadays in cancer therapy, that some hospitals are equipped with their own mini particle accelerators in the basement. Back to CERN. Worse still, the lighter the particle, the more synchrotron energy it emits. Given that electrons are almost 2000 times lighter than protons, mustering the energy needed to circulate them anywhere near as fast as the heavier protons is paradoxically next to impossible. Incidentally, plans are already afoot to build an even more powerful international particle collider,
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which, crucially, would accelerate electrons in a straight line of 40 kilometres before smashing them. The problem of synchrotron radiation doesn’t exist in straight lines. But that won’t happen before the first results from the LHC give an idea if spending billions won’t just feed a black hole.Yet, circular accelerators do have a big advantage, because particles can be ‘stored’, circulating in the ring for hours before being collided. Beyond constraints on the mass and internal complexity of the particle accel-
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erated, that choice is somewhat arbitrary. The key is that mass and energy are interchangeable. Einstein said this with the famous equation E = mc2. So all that matters is that the particle is given enough energy to reach the predicted mass range of the massive Higgs boson. Plans have already been drawn up to upgrade the facility ten years from now to a super-LHC, with denser particle beams. Upgrading the LHC is a cost-effective way of extending research, rather than investing more in an uncertain start or building a brand new experiment. The scale of the LHC caught the attention of the BBC’s Horizon programme. “We spent four days filming at CERN,” says science film director James van der Pool, who made a documentary about the LHC for Horizon, aired in May. “I am overusing superlatives here, but the ambition and scope of the project is extraordinary. It is a truly awesome piece of engineering.” But he says, “you cannot help but wonder if this will turn out like the genome project where you stand at the cusp of major scientific insights, only to discover that there is still more complexity beyond.” www.cern.ch An interview with Sir Martin Rees is available online at www.bluesci.org Tristan Farrow is a PhD student in the Cavendish Laboratory
View of an open interconnection in the LHC particle accelerator tunnel
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Equinox Graphics and Kelly Neaves
Detection Experiments at the LHC A simulation of Higgs boson detection as expected to be produced in the (adapted from a CERN Press & Media image)
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experiment
many collisions are needed. The creation of microscopic black holes is another real possibility. But those would evaporate before they had the chance to swallow CERN! Amy Chesterton
CERN Press & Media
crucial therefore, that all non-neutrino particles are detected accurately. If the Higgs boson is produced it would instantly decay into, and be detected as, the production of two photons. However, this is likely to occur only 1% of the time, which is why so
CERN Press & Media
Discovering new, high-energy particles at the LHC is the job of a total of six detectors located at the tunnel’s collision points. The two largest detectors, ATLAS and CMS, are general purpose detectors whose principal objective is to find the Higgs boson. The other four detectors, namely LHCc, ALICE, TOTEM and LHCf, are smaller and highly specialised. ATLAS and CMS have a stratified structure, with concentric layers around the central collision point, each made of a different material. Each layer detects and tracks a specific type of particle. A complete picture of the physics is obtained by gathering together the information recorded by all the layers in the detector. When protons collide and the byproducts fly apart, the newly-created particles travel through the various layers of the detector. The paths of charged particles are bent by a very strong magnetic field.The momentum of each particle can be measured by the curvature of its path, whilst the charge carried by that particle is revealed by following the direction that the particle takes. The magnet size dictates the detector size, and explains why the detectors attain their gigantic proportions. ATLAS is eight times the volume of CMS due to its novel toroidal magnet, which is much larger than the traditional cylindrical magnet of CMS. Particles firstly penetrate the Silicon Tracker which follows charged particles such as muons, electrons and hadrons. Precision is vital in order to identify the exact origin point of each species. Calorimeters absorb particles into their highly dense metal and calculate the energy by observing the resultant ‘particle shower’. An electromagnet calorimeter absorbs charged particles and photons, whereas the hadron calorimeter absorbs particles such as protons, neutrons, pions and kaons. The outermost layer of the detector is a Muon Spectrometer which identifies and measures highly penetrating muons, which are essentially heavy electrons. Since neutrinos cannot be measured by detectors, their presence is deduced by adding up the total momentum in the collision. It is
CMS
Top: Layout of ATLAS detector, a proposed experiment at the LHC. Bottom: Central view of the ATLAS detector with its eight toroids around the calorimeter.
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Focus
The Elusive Higgs Boson Imagine a world where there is no such concept as mass. All building blocks of matter would be similar to the photon—the particle that carries electromagnetic force and travels at the speed of light. This could be our world if it were not for the existence of a very peculiar particle, the Higgs boson. This hypothesised particle is expected, according to the Standard Model, to give mass to all other particles, including those that make up our bodies, by interacting with them
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Our conception of the world will be defied in many ways
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through the so-called Higgs field. Mass is thought to result from the effect of each particle being slowed down by this omnipresent field, as a sphere would be slowed down when falling through honey. Until now, the existence of this particle has only been postulated—the hope of seeing it lies in the highly energetic proton collisions that will occur
inside the LHC. Here, energy released by smashing particles into one another is literally transmuted into matter, or more precisely, into new particles.According to Einstein’s famous equation, E = mc2, the more massive the particle, the more energetic a collision needs to be in order to produce it.To date, no particle accelerator has been able to create enough energy to reach the predicted mass range of the Higgs. Physicists are now holding their breath for a sign of this enigmatic boson. Interestingly, the Higgs boson predicted by the Standard Model could have a myriad different properties, and different findings could support alternative theories that are more successful in unifying the several forces of nature: electromagnetic, weak and strong forces, and gravity. Incompatibilities between quantum mechanics (which describes interactions at the microscopic scale) and the theory of general relativity (which characterizes the gravitational interactions that become important on the scale of planets and galaxies) can only be alleviated if new concepts and particles are considered. In the theory of supersymmetry, which brings us a step closer to the ‘Theory of Everything’, each elementary particle would have a heavier superpartner and the Higgs boson would be no exception.Thus
if signs of a particle corresponding to a supersymmetric Higgs are found, even more exciting possibilities open up, offering proofs and explanations for the elusive dark matter, whose invisible presence can currently only be deduced from its gravitational effects on visible matter. Our conception of the world will be defied in many ways by this new-generation accelerator. More daring theories have raised the possibility that our Universe is trapped in a three-dimensional ‘membrane’ embedded in a higher dimensional space—which could explain the apparent weakness of gravitational force.We may be unaware of such additional dimensions due to the fact that electromagnetic forces do not permeate them, but gravitons, the particles that carry gravity, might be able to cross into them and escape to extra-dimensional space. Unexpected energy levels resulting from the collision of specific particles at the LHC may be a hint that gravitons are being produced and ‘lost’ to other dimensions. So we may well be on the brink of discovering that the 3D world we perceive is only a small bubble in a 10dimensional Universe! Alexandra Lopes
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A representation of all the fundamental particles believed to exist (adapted from a figure produced by CERN Press & Media)
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Supersymmetry lenses’ of dark matter in its path. Currently, cosmologists believe there is nearly five times more dark matter than normal matter in our Universe. A promising potential explanation for dark matter is the theory of supersymmetry, which could be confirmed when the LHC is switched on. One of the characteristics of every elementary particle is its spin, which measures its angular momentum. Supersymmetry proposes that each particle is related to
NASA, ESA, and R. Massey (California Institute of Technology)
Dark matter is the mysterious, undetected ‘missing mass’ which makes up nearly 23% of the Universe. As the name suggests, it cannot be observed directly, but astronomers find situations in which the gravitational forces are much greater than should be caused by the visible matter present. For example, most galaxies rotate much faster than would be expected from the number and mass of the stars they contain; and light from distant objects is distorted and amplified by hidden ‘gravitational
another—its so-called ‘superpartner’— which has a related value of spin. The theory of supersymmetry conveniently explains several significant omissions within the current Standard Model—solving the so-called ‘hierachy problem’ related to the anomalous mass of the Higgs boson, and correctly predicting the relative strengths of the electrostatic, strong and weak nuclear forces. It also appears that string theory, the current favourite route towards a Theory of Everything, actually requires supersymmetr y in order to be consistent. However, none of the superpartners for any known particles have yet been discovered. It is hoped that at the extremely high energies reached by the LHC, these superparticles (or ‘sparticles’) will be created and detected. It is these particles that are thought to make up dark matter. Since every particle has a superpartner, incorporating supersymmetry into the Standard Model means doubling the number of particles thought to exist. Consequently, theories of supersymmetry are highly complex, because so many interactions between different combinations of particles can occur. Michaela Freeland
Three-dimensional distribution of dark matter in the Universe
From Print to Podcast BlueSci’s Film Team travel to Geneva to produce a documentary on the Large Hadron Collider
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the internet—the group finally flew out to Geneva on 1 August. None of this would have been possible without the generous funding from the Institute of Physics, or the immensely appreciated help from all the people the team met at CERN. On location for four days, the group hardly spent a moment apart. They had access to all areas at CERN, filming the 8 storey-high detectors located 100 metres below the Earth’s surface, as well as the more modestly sized physicists, who had big personalities nonetheless. The Team came away with some amazing footage, and some answers to questions which play on the minds of many, not just the scientists. The Film Team’s efforts are still being carefully stitched together. Music and sound will be provided by Jonathon Hill, a Cambridge music student. Graphics are being created by Jon Heras, a former BlueSci pictures editor and founder of Equinox Graphics (www.e-nox.net). You will be able to
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catch the 15 minute documentary at the BlueSci launch or on the BlueSci website from the middle of October. www.bluesci.org Vincent Carta
Vincent Carta
The BlueSci Film Team, led by the Head of Film, Chloe Stockford, had taken it upon themselves to produce something special. The ambitious project was as follows: to fly out to CERN, Geneva, and interview some of the biggest names in particle physics.The intention was to make CERN accessible to the masses. After all, what are the governments of the world spending billions of taxpayers’ money on? No, it’s not some doomsday device as the media would love to portray. The Team were going out to dispel the pop-science rumours and shed light on what was actually important—the Higgs and its effects, black holes, dark matter, and the immense scale of international collaboration in finding the answers to the most fundamental questions posed by physics today.The project was born. After months of meticulous planning, question writing, storyboarding and hours spent exchanging emails with CERN—incidentally, the birth place of
From left to right: Vincent Carta, Benjamin Collie, Kelly Neaves, Amy Chesterton, Adam Moughton, Chloe Stockford
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Elevate yourself
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31 October 2007 The Institute of Physics, London
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IOP Institute of Physics
This book is a new, abridged version of the findings and conclusions of the Copenhagen Consensus, a project set up
by Bjørn Lomborg, in which leading economists met to prioritise goals for global development and welfare.The full report of the 2004 meeting, Global Crises, Global Solutions, weighs in at 700 pages. How to spend $50 billion to Make the World a Better Place, on the other hand, is a mere 200 pages, and aims, in the words of its publishers, to provide a “serious yet accessible springboard for debate and discussion.” The goal of the 2004 conference was to produce a ranked list of the order in which the greatest challenges facing the world should be solved, given an extra $50 billion, and this book is a collection of essays by the participants. They deal with climate change, disease, conflict, education, corruption, malnutrition, migration, sanitation and trade. It is certainly a wide-reaching remit, and the book aims to provide a short summary of the arguments made and the responses to them. This is a book about economics and social sciences, and it is written by economists. I initially tried to read the book as a scientist, but rapidly became exasperated by apparently sweeping, unreferenced statements. However, this isn’t
Human memory can be described as fleeting, unpredictable and unreliable. Why is it that we can remember a humiliating event in minute detail but often fail to retell past joyous encounters with equal vivacity? Why can we remember where we were during a moment of national importance but can’t seem to remember the word on the tip of our tongue? In his titillating examination of autobiographical memory, Douwe Draaisma, professor of History of Psychology at the University of Groningen in the Netherlands, attempts to answer these questions and asks many others in his book on memory and our past. Draaisma begins with the first recorded memory research: the memory experiments devised independently by English scientist Sir Francis Galton and German philosopher Hermann Ebbinghaus in the late nineteenth century. These two men, on opposite sides of the science and arts spectrum, identified memory as a double-edged phenomenon. On the one hand our memory is subject to statistical analysis, but on the other it is riddled with inherent unquantifiable characteristics. This tension underlies much of Draaisma’s investigations. From this platform, Draaisma launches the reader into a chronologically organized look at memory. Some memories, Draaisma suggests, are kept vivid because they often include life-time firsts, like a
first kiss or first day at school.As we move into old age, our memories lose vibrancy because our lives settle into a monotony. A lack of new experiences alters our perception of memory, leading many to think that life speeds up as we get older simply because there are fewer landmarks to signpost its passing. Whilst this forms the crux of Draaisma’s argument, along the way he takes us on a fascinating journey through the labyrinthine paths that our memory can take, including déjà vu, savant syndrome, and traumatic memory. In effect, he offers a glimpse into all aspects of memory and supports his assertions with a variety of data, ranging from quantitative analysis to personal recollection and photographs. The only shortfall of Draaisma’s wellresearched book is that it is at times an erratic read. By rapidly hopping from one memory-related phenomenon to the next he steers away from the book’s main premise and fails to draw links back to his argument. However, these minor digressions add rich layers to Draaisma’s work and stimulate the reader to wander into the mysterious neurological workings of memory. It is not surprising that Draaisma’s book was shortlisted for the Aventis Prize for Science Books in 2005. Its approach, that of a historian of science, situates memory within a historical context, as well as an experimental one, and
Edited by Bjørn Lomborg (Cambridge University Press, 2006, £9.99)
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really what this book is about—as a summary of a larger work, it’s about getting a feel for the problems facing the world, and gaining a better practical understanding of the steps we need to take to solve them. The first chapter,‘Meeting the challenge of global warming’, deals with the economic impact of climate change. The problem, we learn, is that huge investments are required now to bring about changes in the future, and these changes may not become apparent for decades or even centuries to come. The main debate in the chapter centres on how to value these future benefits against short-term costs. All in all, the book provides an insight into the economics of human progress and development. It also puts into perspective the major issues facing the global population today. You may not agree with everything you read, but you’ll almost certainly emerge with a changed view of what’s really important for the world.
B o o k R ev i ew s
Book reviews
Tom Walters is a PhD student in the Department of Physiology, Development and Neuroscience
Written by Douwe Draaisma (Cambridge University Press, 2004, £19.99) draws from medicine, politics and sociology. His writing is further enhanced by the inclusion of pleasant and insightful literary references, making the book an engaging read for the scientist and nonscientist alike. Margaret Olszewski is a PhD student in the Department of History and Philosophy of Science
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Equinox Graphics and Kelly Neaves
Gillian Brodie investigates what has gone wrong with our immune system
Kelly Neaves
Many important scientific discoveries begin with simple observations. A notable increase in the number of hayfever sufferers, particularly over the last 30 years, is one observation that set Professor Strachan thinking. Working at the London School of Hygiene and Tropical Medicine, Professor Strachan described a peculiar correlation between the increased occurence of this allergy and decreased household sizes in the UK. Seemingly inscrutably related, hay-fever was nicknamed the ‘post industrial revolution epidemic’. Prior to the industrial revolution, a sizeable portion of the population died from diseases spread owing to cramped living conditions. Typhoid and smallpox were rife, as was cholera from contaminated water supplies and open sewers. Post-industrial Britain, however, witnessed the rise of considerably cleaner cities and a subsequent decline in the transmission of diseases. This coincided with rapid medical advances and virtual eradication of many debilitating diseases.
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Scientific discoveries were gradually eliminating the threat of human infection by micro-organisms. Further research revealed that this phenomenon extended far beyond hay-fever and British households; an interesting pattern emerged between developing and developed countries: westernised populations appeared to have distinctly higher
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Scientific discoveries are gradually eliminating the threat of human infection
incidences of autoimmune and allergic conditions in general. This phenomenon was dubbed the ‘hygiene hypothesis’. But why would a pathogen-free environment produce such outcomes? The immune system relies on interactions between hundreds of immune cells and molecules, all with specific roles. These dynamic interactions have been
A false-coloured scanning electron micrograph of pollen
greatly influenced by the surrounding environment in which they matured, as with every living system or organism. Micro-organisms have been a constant presence throughout the immune system’s evolution, and consequently they have played a prominent role in shaping our defence network.With the advent of antibiotics and vaccinations these
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pathogens are being flushed from our natural environmental pool. Allergies occur when a misguided assault is mounted against a foreign substance, whether that be pollen or peanuts. The immune system’s T cells can inappropriately recognise these innocent substances as harmful, and react to protect their host. Armies of immune cells respond to these false alarms, sometimes resulting in symptoms similar to those seen during genuine infections when the body is defending itself against a truly dangerous organism. Allergies can often be managed, mainly through avoidance of the offending substance. In certain cases however, severe allergic reactions may produce anaphylactic shock, which can prove fatal through collapse of the heart and lungs. Individuals can inherit allergic tendencies from their parents but, with the current high rate of allergic conditions, it is speculated that environmental factors may be more important than genetics in today’s climate. Autoimmunity, on the other hand, arises when the immune system fails in one of its most critical roles: to discriminate effectively between foreign agents and the body’s own tissues.The manifestations of such an error can be deadly serious. Type 1 diabetes (T1D) is amongst the most common autoimmune diseases in the UK. The inability to store ingested glucose through lack of insulin production would prove fatal if it were not kept under constant control with medication. Multiple sclerosis (MS) is another autoimmune disease, where brain and spinal cord function are lost through an
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onslaught of immune attack on the protective fatty layer that surrounds nerves, the myelin sheath. In the case of MS, inflammation is thought to cause a leak in the blood-brain barrier, allowing T cells to enter the central nervous system, a privileged site of the body that never usually comes into contact with immune cells. Acquainting themselves with a completely unknown tissue, the T cells initiate an attack as if it were presented with invading micro-organisms. Layers of myelin are able to reform leading to periods of relapse and remission, but repeated attacks result in the build up of scar-like plaques around damaged nerves.The patient becomes progressively more disabled, and is eventually unable to co-ordinate even simple tasks. The massive modern-day increase in new cases of immune-related diseases such as hay-fever and T1D provides strong evidence that environmental factors are at play. Before the discovery of insulin in the 1920s, T1D was a rare and deadly condition. Worryingly, during the last 10 years, its prevalence has doubled in under-five-year-olds, and it is now increasing in the UK by around 3.5% every year, a rate that cannot possibly be accounted for by natural genetic change. So have our immune systems become restless owing to a lack of challenges from environmental stimuli? Fortunately, current research gives cause for hope. T cells follow one of two main developmental pathways.Those belonging to individuals prone to autoimmune disease are thought to migrate down a path in which inflammatory factors cause cells to become aggressive. These cells may then attack susceptible tissues. Professor Anne Cooke and her group at the University of Cambridge’s Department of Pathology are studying the immune-modulating effects of the parasite Schistosomiasis mansoni, a flatworm prevalent in Africa, Asia and
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South America. She has shown that during parasitic worm infections, the immune response can be skewed away from this aggressive course, and instead favour a path whereby less destructive cell types form. Parasites can also influence the formation of regulatory cells. These recognise dangerous T cells with the potential to react against host tissues, and curb their action before any damage occurs.
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extremely serious and debilitating cases of autoimmunity? Conventional wisdom tells us that infections of any sort—bacterial, viral, parasitic, fungal—are to be avoided at all costs. It may prove fortunate therefore that the work being carried out at the University of Cambridge has demonstrated that in order to experience protection, an individual may not need to be
Micro-organisms have been a constant presence throughout evolution
This bewildering protective action of pathogens is mirrored in many different types of micro-organism, including that of Salmonella typhimurium. Mice infected with this bacterium have long-lasting protection against T1D development due to a small number of protective immune cells generated during the infection. These cells have the ability to survive long after the pathogen has been cleared, and continue to protect the host. Another study, carried out in South America, monitored the progression of a group of MS patients over a two-year period. On entering the study, blood tests revealed elevated levels of a population of cells involved in the innate immune response called eosinophils, an indicator of a parasitic infection. Further tests revealed a number of the patients were indeed playing host to different species of worm. As the parasites were not causing serious health problems, no treatment was administered to eliminate them. By the end of the study, infected patients showed remarkably fewer relapses of MS and their brain scans appeared far healthier with fewer areas of scarring. Could this offer new hope for treating
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infected with a whole, live organism: a soluble extract of the schistosome worm or egg can also protect against T1D development in mice if administered before onset of the disease. This could prove to be a promising new therapy when future advances can accurately identify susceptible individuals. Professor Cooke believes that “we could identify developmental pathways that if tweaked or changed, might be able to get the immune system into a state that is more regulatory,” to help prevent allergic and autoimmune conditions. As privileged as we may be to live in a largely disease-free environment, many of us now face attack from our own defence system. Given that we are beleaguered by so few pathogens today in evolutionary terms, microbial by-products may need to be used to retrain our immune system. Reintroducing some of our natural history may help to discipline our over-enthusiastic immune system—a lesson to be learned from our neighbours in the developing world. Gillian Brodie is a graduate student in the Department of Pathology
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James Bullock explores the underwater world of sea monsters With our deep seas teeming with a seemingly endless array of fascinating creatures, no animal captures the imagination quite like the giant squid. A sea monster straight out of seafaring legend, it has become the inspiration for countless works of fiction, from the early Norse tales of the Kraken to Jules Verne’s Twenty Thousand Leagues Under the Sea and the film Pirates of the Caribbean. Neither is it ever far from the scientific and even global headlines whenever new discoveries are announced regarding this enigmatic animal. The giant squid, Architeuthis dux, is a genuinely massive cephalopod belonging to the Architeuthidae family, which simply translates as ‘arch-squid’. The largest specimens are estimated to be an enormous 13 metres from caudal fin to tentacle tip, with the mantle which makes up the bulk of the squid reaching lengths of up to two-and-a-half metres. That’s a total length of more than seven times the height of an average man and puts the giant squid amongst the largest living organisms on Earth. Although claims of 20-metre-plus squid are widely discredited (with accusations of ‘tentacle stretching’), there are still many who believe there are even larger cephalopods hiding deep in the oceans.
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Squid-like sea monsters have been written about since Norse sailors first encountered them in the thirteenth century. Architeuthis, however, was not scientifically classified until 1857 when the Danish zoologist Japetus Steenstrup succeeded in bringing it to the attention of his contemporaries, who were studying specimens that had been causing interest by intermittently washing up on beaches around the globe. At first, his work
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Squid-like sea monsters have been written about since the thirteenth century
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was based on local legends and sketchy evidence, with samples dating back as far as the 1700s. But as the number of sightings of dead animals increased, the sceptical scientific community gradually began to accept the giant squid as more than just a tall story for sailors. Yale’s Professor Addison E.Verrill added credi-
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bility to Stennstrup’s research in 1873 when he identified two beached ‘Kraken’ as Architeuthis. Also in 1873, a group of frightened Newfoundland fishermen killed “a sea monster” and took it to their local priest, who displayed it draped over his bathtub. This was the first complete giant squid specimen available to science.Two mysterious mass strandings followed during the late nineteenth century, which left a number of giant squid beached off the coast of Newfoundland, Canada, and around the New Zealand shoreline. Still no explanation has been accepted as to the reason for these, and to date there has been no repeat of this strange occurrence. Nevertheless, as a result, many giant squid specimens were made available for scientific study. So what has changed since then and, Johnny Depp aside, how does Architeuthis fit into the public consciousness and twenty-first century science? In September 2005, headlines were made around the world when two Japanese researchers, Tsunemi Kubodera and Kyoichi Mori, finally succeeded in photographing the living cephalopod in its natural habitat, 900 metres below the surface. The photos showed a mass of tentacles emerging from the black depths and vigorously attacking a line baited
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Adam Moughton
In the Wake of the Giant Squid
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The giant squid is an active hunter, snaring its prey with its powerful tentacles
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Wikimedia Commons
The key to locating Architeuthis was to track its principal predator, the sperm whale (Physeter macrocephalus). Believed until recently (when joined by the sleeper shark) to be the only animals big enough to predate the giant squid, sperm whale specimens are regularly recovered with undigested chitin squid beaks in their stomachs. Giant sucker scars on the whales’ skin suggest that the conflict is not entirely one-sided, and much focus has been placed on these encounters as a basic location system for giant squid. Dr Kubodera explains, “the reason why we thought those large
Giant squid from Logy Bay, Newfoundland, in Reverend Moses Harvey's bathtub, November/December, 1873
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mesopelagic squids could escape from trawl nets and submersibles when approached was due to the unusual undulation and strong light they produced. Instead, we applied a compact underwater camera and video system which caused a minimum disturbance to the deep-sea environment.” This approach has proved extremely successful, as he has obtained images not only of Architeuthis, but also of the beautiful Taningia danae octopus-squid, filmed earlier this year exhibiting a stunning bioluminescent hunting behaviour. Besides this, last December, Dr Kubodera followed up on his breakthrough images with the first ever video of a giant squid as it was pulled to the surface from a depth of 650 metres. It is often said that the deep ocean is less explored than the surface of the Moon but it is safe to say that there is a lot more life in the oceans. Without doubt there are many undiscovered species left at the bottom of our seas and it is very tempting to believe that there are still more monsters lurking out there. Dr Kubodera agrees: “There should be a huge biomass of large cephalopods existing in the mesopelagic waters, given the feeding habits of the top marine predators, especially the sperm whales.” Yet, he notes, they are largely hidden “behind the darkness of the deep-sea.” This was reinforced in 1925 when it was discovered that Architeuthis was not the only massive cephalopod inhabiting our oceans.Two strange barbed tentacles were found in the stomach of a sperm whale. Morphologically different from the giant squid due to the presence of swivelling hooked barbs protruding from the tentacle suckers, this identified a species previously unknown to science, the so-called ‘colossal’ squid. The colossal squid (Mesonychoteuthis hamiltoni) is in fact even larger than the Architeuthis, at least in terms of weight (it is often misreported as being longer, though its tentacles are usually less pronounced). Its football-sized eyes are also the biggest of any animal. Very little is known about the colossal squid and only a few specimens have ever been recorded—though in February this year a trawler in the Antarctic Ross Sea picked up the largest colossal squid, and the first male specimen, ever seen. At 10 metres long and just short of half a tonne, it is not only the largest squid, but the largest invertebrate ever recorded. The rarity of the creatures has meant that our understanding of deep-sea cephalopods is limited. In an interesting historical note, the giant squid was proposed as an explanation for another one of the ocean’s mysteries—the ‘St Augustine Monster’. An enormous five tonne mass of rotting white flesh that washed ashore in Florida in 1896, it is the most famous example of what are now commonly known as ‘globsters’. It was believed by many observers (including
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with smaller squid. It was so active that, having been snared, it took the squid four hours to struggle free, leaving behind a five-and-a-half-metre-long tentacle for the scientists to study. This unexpected sample allowed Kubodera to confirm the identity of the specimen through DNA sequencing and morphological analysis of the paired suckers, which are unique to giant squid, and helped to put its total length at around eight metres.The key outcome from this study was the wider acceptance of the idea that the squid is an active and aggressive predator, snaring its prey with its powerful feeding tentacles, rather than a passive drifting scavenger.
The largest squid found was 13m long
the attending physician and many subsequent researchers) to be a stranded “gigantic octopus,” with a predicted tentacle span of anything up to 60 meters. However, this idea changed in 1995, when Sidney Pierce and colleagues took a closer look at a sample that had been kept for posterity at the Smithsonian Institute. They used electron microscopy to show that the material was almost pure collagen, claiming that it had neither the necessary fibre arrangement nor the biochemical signature to be of invertebrate origin. They came to the rather more mundane conclusion that the giant corpse was in fact the decomposed skin and blubber of a sperm whale, largely dismissing the idea of the gigantic octopus. Several species of the more modest giant octopus do however exist and are well documented. The biggest confirmed measurement belongs to the rare four
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It’s tempting to believe that there are more monsters lurking out there
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metre-long gelatinous octopus, Haliphron atlanticus, as recorded in 2002 by New Zealand biologist Dr Steve O’Shea. There is undoubtedly more work to be done before we fully understand the giant squid. Despite being found in every ocean of the world, very little is known about its life cycle and nothing is known of its social behaviour. Plans are already in place to attempt to raise squid larvae in aquariums in the hope of observing some of its life cycle. As research continues and commercial fishermen begin to trawl at even greater depths for healthy fish stocks, bringing more intact specimens up to the surface, it seems only a matter of time until we know what else the deep ocean is hiding from us. Here be monsters… James Bullock is a PhD student in the Department of Zoology
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Kelly Neaves
Mining the Moon Michaela Freeland explores a far-reaching project to replace fossil fuels on a global scale Robotic mining vehicles trawling the Moon's surface; cargo spacecraft delivering the lode back to Earth; a clean energy source, just 150 tonnes of which could power the world for a year. It is a futuristic vision that could be surprisingly close at hand. The super-fuel behind this vision is helium-3, an isotope containing one fewer neutron than standard helium, and extremely rare on Earth yet tantalisingly abundant in the wider Solar System.
A futuristic vision could be surprisingly close at hand
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In spite of the obvious difficulties in transporting the extracted isotope from elsewhere back to Earth, lunar helium-3 is widely regarded as having huge potential for power generation due to the vast amounts of energy released by just small quantities in nuclear fusion reactions. The current annual consumption in the USA is over 1100 million tonnes of coal, whereas a mere 25 tonnes of helium-3 could supply the same electricity demand. The nucleus of a light element can achieve greater stability by fusing with another to form a heavier element, possibly with the release of surplus protons and neutrons. The total mass of the final products is slightly less than that of the
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original nuclei—and Einstein’s formula E = mc2 relates this mass difference to the energy released in the fusion process. By harnessing this so-called ‘binding energy’, many researchers believe that, ultimately, fusion power could provide all our planet’s electricity requirements. However, current facilities, such as the ITER facility (meaning “the way” in Latin) in France and the NIF (National Ignition Facility) in California, are still very much at the experimental stage— even optimistic forecasters acknowledge that commercial power generation cannot be expected until about 2050. The current reactors utilise deuteriumtritium (D-T) fusion (deuterium being an isotope of hydrogen, containing one proton and one neutron), the simplest nuclear fusion process.A helium-3 nucleus is fused with a deuterium nucleus to produce an ion of standard helium (helium-4, with two protons and two neutrons) and a free, high-energy proton. The greater charges on a helium-3 ion means that the electrostatic repulsion between it and the deuterium nucleus is stronger than in D-T fusion, hence more energy (through higher temperatures) is required to start the process. It also means that the helium-3 reaction proceeds more slowly. However, the great advantage of helium-3 fusion over other reactions is that electric, rather than magnetic, fields can be used to control the process, focusing the reacting nuclei into a dense core, and guiding the resulting protons, converting their energy into electricity.The appeal of helium-3 fusion is further increased by the absence of radioactive waste and byproducts such as water in the reaction.
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Scientists have known the potential of helium-3 for some time—the isotope’s existence was first theorised at the Cavendish Laboratories in 1934 by nuclear physicist Mark Oliphant, and it was first observed by Alvarez and Cornog at the Lawrence Berkeley National Laboratory five years later. Only recently, however, has fusion technology matured to the point of experimental helium-3 reactors being developed. A team led by Gerald Kulcinski at the University of Wisconsin recently reported to have achieved helium-3-deuterium fusion at a sustained rate of 2.6 million reactions per second. Whilst still far below the rate required for a power plant, Kulcinski argues that this provides a pleasing proof of principle. Eventually, it is estimated that energy generation efficiencies of up to 70% may be possible.
Mining the Moon is an increasingly appealing option
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But why do we need to go to the Moon to obtain this promising resource? Current stocks of helium-3 on Earth are simply too small to sustain a power-generating industry. The deposits that exist on the Moon (and the trace geological deposits on Earth) were originally produced by fusion reactions in the Sun, and deposited on the surface by the solar wind. The isotope is then dispersed
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scientists believe the most viable areas for mining would be the maria or ‘seas’ on the far side of the Moon.The mining process would involve heating the soil to 700˚C, vaporizing helium-3 so that it could be collected and stored in its gaseous form. Several designs for robotic mining vehicles have already been developed. Even if the technological hurdles are being tackled, there remain significant legal obstacles facing the enterprises seeking to mine the Moon. The current state of regulation over the lunar surface is widely accepted as being inadequate, in large part because the major relevant agreements, such as the 1967 Outer Space Treaty, were drawn up in a Cold War climate, when few countries possessed space programmes. Currently, the Moon (and all of outer space) has a unique legal status as res communis— “Common Heritage for Mankind”— and, as such, activities taking place on the Moon cannot be subject to control by a particular body or nation. Therefore, there can be no formal property rights claimed by individuals, companies or indeed countries. Furthermore, the 1979 Moon Agreement makes matters more complicated for lunar mining operations, expressly stating that the surface (and subsurface) “shall [not] become property of any State, international…or national organization…or of any natural person.” A system of granting leasehold rights to mining companies has been proposed, but it remains unclear which bodies would oversee and regulate the system.
Helium-3 enthusiasts continue to aim even higher
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pendent country.” Perhaps more realistically, lunar mining enterprise could be the forerunner of larger-scale mining of the helium-rich gas giants in the outer Solar System. Following the resolution of these legal and political issues surrounding the lunar industry, the pace of technological developments suggests that exploratory mining on the Moon could begin by 2020. Nikolai Sevastyanov, President of Russia’s RKK Energiya—the state-run enterprise which developed the Soyuz and Prospect spacecraft and plans to establish lunar mining bases in the next 10-15 years— comments: “Maybe it's science fiction right now, but we need to start moving in that direction.” Michaela Freeland is a third year undergraduate studying Mathematics
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throughout the lunar topsoil by meteorite impacts. Its rarity on Earth is a result of the solar wind being deflected away from the planet by the Earth’s magnetic field, but geological deposits of helium-3 on Earth are difficult to gauge—estimated at just half a tonne within the Earth’s crust—and virtually inaccessible. Small amounts are released in certain volcanoes, such as those in the Hawaiian islands, but extracting the isotope from these deep deposits would require more energy than the fuel would provide. The current stocks of helium-3 that we do have were largely produced as an end product of the radioactive decay of tritium, a radioisotope of hydrogen containing one proton and two neutrons. Since tritium is commonly used in nuclear warheads, much of our helium-3 has been obtained since the 1950s from the decommissioning of nuclear weapons in the US arsenal. Producing helium-3 in this way, however, would not be economically feasible on an industrial scale due to the difficulties in producing and storing tritium gas, and the inefficiency of the reaction, with the production of one tonne of helium-3 requiring 18 times this amount of tritium. Thus, mining the Moon is an increasingly appealing option, and is attracting growing attention, including that of the emerging and ambitious space programmes of India and China.The former Indian President, Dr Kalam, for example, stated that “the moon contains 10 times more energy in the form of helium-3 than all the fossil fuels on the earth.” Ouyang Ziyuan, Director of the Chinese Lunar Exploration Programme, was more specific: “Each year three space shuttle missions could bring enough fuel for all human beings across the world.” The first step toward helium-3 extraction taken by the Chinese team was a satellite survey of the Moon’s surface, begun in 2004. The greatest concentrations of the isotope should be found in older regions of the surface, since they have been exposed to the solar wind for longer, and are composed of fine aggregate sand that absorbs the isotope. So too does titanium dioxide, hence regions with high concentrations of this chemical are also promising. Looking at the lunar surveys,
As on Earth, there is also the issue of the environmental disturbance caused by mining activities. The contamination and pollution of space is a consideration being brought increasingly to the fore with, for example, the retrieval from the Moon of stowaway E. coli bacteria from the Apollo 12 mission.The ring of ‘space junk’ in Earth orbit, which NASA estimates amounts to 5500 tonnes, presents a disturbing precedent of discarded mining operations left strewn across the lunar surface. In spite of these major legal obstacles, helium-3 enthusiasts continue, quite literally, to aim even higher in their plans for mining enterprises. Harris Hagan Schmidt, a US Senator, geologist and Apollo 17 astronaut suggested in a 2003 US Government report that helium-3 mining would be the best way to finance further exploration and settlement on the Moon. Wisconsin’s Kulcinski goes further, envisioning the Moon's helium3 as an inter-planetary trading commodity “when the moon becomes an inde-
Moon volumes represent the mass of substance required to produce a unit of energy. For example, 5.4 g of Helium-3 could produce 1000 kWh of energy.
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Stem Cells and Cancer Brynn Kvinlaug reveals the role of stem cells in cancer where tumour cells survive: the tumour reappears. Some current evidence suggests that CSCs are at the core of tumour formation. Even if nearly all the tumour mass is removed, a few remaining CSCs may be all that is necessary for cancer to recur. CSCs were first identified in patients with acute myeloid leukaemia, but since then they have also been identified in solid tumours in the breast, brain and other organs. In the healthy state, each of these organs is comprised of the mature, differentiated, short-lived cell types characteristic of the tissue. The mature cells are replenished by long-lived stem cells unique to the organ. Through a tightly regulated process, each stem cell has the ability either to form another stem cell through selfrenewal, or to differentiate into the progenitor cells that give rise to the mature cell types of that tissue. These daughter progenitor cells are more restricted in their lineage choice and divide frequently. To date, several factors have been found to have a role in controlling the selfrenewal of haematopoietic stem cells (HSCs)—stem cells of the blood. These factors include specialized proteins involved in gene transcription, as well as molecular signalling pathways within the cells. In leukaemia, mutation of this tightly regulated process occurs and the selfrenewal of the stem cell becomes deregulated.This may then lead to its development into a CSC. However, as most biological pathways and features are the same in normal stem cells and CSCs, it is very difficult to target CSCs specifically with medical intervention. The few unique differences that do exist may be the only means of eradicating the CSC population, while sparing normal and healthy stem cells.
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Have you ever experienced difficulty removing a dandelion from your garden? In an attempt to rid the garden of its nuisance, the roots are dug out, but even a minute portion remaining can enable the weed to grow back with a vengeance. The root cells that allow this regeneration can be likened to a specific group of cells within cancerous tumours, termed cancer stem cells (CSCs). Normal stem cells are vital to the body, serving to provide new populations of cells for growth and repair. CSCs have similar characteristics to normal stem cells, but with mutations that give them the dangerous ability to reform tumours if not removed from the body. Stem cells frequently feature in the media as potential cures for degenerative diseases. As cells with infinite capabilities to divide and differentiate into new cell types, they may eventually be used to regenerate tissues and organs. When mutated, however, stem cells also seem to play a role in cancer, and can develop into entire tumours if even a few cells are present. Cancer stem cells may soon change how we identify and treat the disease, becoming a new target in the battle to find an effective cancer cure. Despite improvements to the early detection and treatment of cancer, current therapies are limited in their ability to cure the disease completely. Common methods of cancer treatment such as radiotherapy, chemotherapy and surgery all target and reduce the tumour mass as a whole.These treatments are extremely toxic and nonspecific, destroying not only the susceptible tumour cells, but also healthy neighbouring cells. Despite such toxic treatments, complications frequently arise
Stem cell self-renewal and differentiation pathways
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Importantly, last year, two groups demonstrated that the removal of a protein called the phosphatase and tensin homologue (PTEN) gave rise to differentiation changes of HSCs and the subsequent development of leukaemia. PTEN normally works in the cell by terminating
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Evidence suggests that cancer stem cells are at the core of tumour formation
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the positive growth signals that promote cell proliferation. Inactivation of PTEN could lead to increased growth signalling and transformation into a CSC. Other research has found that CSCs in breast tumours have different types of protein molecules on their surface from normal breast stem cells. Such differences between healthy and cancerous stem cells will need to be exploited in the development of new therapies if better prognoses are to be achieved. Another consequence of the discovery of CSCs is that the tumour mass is no longer viewed as a homogeneous entity. Current evidence suggests that a small group of CSCs amongst the other cells of blood and solid tumours are specifically responsible for tumour growth and resistance to therapeutic agents. For example, these cells can contain more membrane efflux pumps compared to normal stem cells.These pumps are capable of pumping chemotherapeutic drugs back out of the cell, making CSCs more resistant to treatment. Other mechanisms that CSCs adopt include alterations to their cell cycle and activation of DNA repair mechanisms, protecting them from radiotherapy. Although no CSC-specific drugs have reached clinical trials, it is only a matter of time until our understanding of these destructive cells improves. Targeting these cells directly may hold the key to effectively treating cancer. Just as the garden weed is tackled, to truly eradicate cancer, tumours must be pulled out at their roots. Brynn Kvinlaug is a PhD student at the Cambridge Institute for Medical Research
Michaelmas 2007
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Alexandra Lopes explores the science behind feeling pain
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Have we found an on/off switch for pain in SCN9A?
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It is one thing to bear pain courageously, but remarkably, a few people do not know what pain is at all. The first scientific report of congenital indifference to pain goes back to the early twentieth century, with the description of a man who performed as a human pincushion in a circus. Since then, this condition has been well characterized. Typically, such individuals have a complete absence of any feeling of pain, in spite of having the sensation of temperature and pressure. Furthermore, they have no detectable neurological damage. The biological reason behind this condition has been unearthed only recently. In 2006, a genetic analysis was performed in three families from northern Pakistan who were indifferent to pain. The team, led by C. Geoffrey Woods, a medical geneticist at the Cambridge Institute for Medical Research, identified the gene involved—SCN9A. This gene was found to encode the alpha subunit of a voltagegated sodium channel. Sodium channels are located in the membrane of excitable
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cells, neurons in this case, and underlie the generation of action potentials by transporting sodium ions into the cell upon stimulation. In the patients who felt no pain, SCN9A was mutated, preventing proper functioning of the channel. The sodium channel encoded by SCN9A is highly expressed in neurons that transmit pain signals, and may therefore be needed to make the signals that carry information about pain to the brain. Furthermore, although it is also expressed in neurons which have functions other than pain perception, mutations in SCN9A still seem completely specific to pain. It is possible that for other stimuli, different sodium channels may compensate for SCN9A, allowing them to be felt. Indeed, although insensitive to pain, the patients studied were all able to perceive touch, temperature and pressure. This study has been extended in a recent report from researchers in Canada to a larger number of families of seven nationalities, reported to be indifferent to painful stimuli such as wounds, dental abscesses, ulcers and remarkably, to nonanesthetized surgery. According to this report, only 30 cases of this condition are known worldwide. From the two studies, it emerges that inactivating defects in SCN9A have a very similar outcome in individuals from diverse human populations. Such defects either result in a truncated form of the protein being produced, or to a process termed ‘nonsense-mediated decay’, whereby the mutation prevents the protein from being produced at all. The central role of SCN9A in pain perception mechanisms has become even
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more irrefutable by the parallel finding that other types of defects in the gene have the opposite effect, resulting in episodic acute pain syndromes. These defects seem to make the channel over-sensitive to pain stimuli.The individuals suffering from the associated disorders feel intense pain caused by everyday activities such as walking, stretching and experiencing cold. Have we found an on/off switch for pain in SCN9A? If so, this finding will have an enormous potential for the development of new analgesic drugs. Not only could the blockage of this specific sodium channel completely eliminate pain, such a drug may also avoid the sideeffects of less specific analgesics. Current neurodepressive drugs, for example the local anesthetic, lidocaine, affect all sodium channel proteins and can have dangerous effects such as cardiovascular disturbances, and can even interfere with the central nervous system when administered in high doses. As the prospect of a global analgesic rises, new concerns are thrown into the equation. By abolishing the feeling of pain, physicians will be relieving suffering, yet will also be shutting down the body’s alarm sensor. Although otherwise healthy, several patients mutant in SCN9A had accidentally harmed themselves as children due to being unable to feel pain. So whilst the discovery of SCN9A signifies promising developments in pain medicine, we should remember that pain is indeed useful, and is likely here to stay. Alexandra Lopes is a postdoc in the Department of Pathology
Sonia Aguera
Pain signifies discomfort, suffering and even agony...but not to everyone. By analysing individuals who cannot feel pain, researchers have recently found that changes to a single gene affect whether the body is capable of experiencing painful sensations. In addition to shedding light on how the body perceives pain, these findings may pave the way towards better forms of analgesic medicine. The word pain conveys a highly subjective experience with several dimensions.This includes both how pain is evaluated, for example how strong a painful sensation will feel, and also the different emotions that may be evoked from painful experiences. It is well known that pain thresholds vary between individuals. Such differences are evident in street performers who undertake daring stunts seemingly unaffected, though most other people would cry out in agony.
A schematic diagram of a voltage-gated sodium channel
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Equinox Graphics and Kelly Neaves
How Green is Your Lab?
Dr Joanna Baxter finds out what fellow scientists can do to keep Cambridge green Science has never been easy on the purse strings but now it appears that sometimes it can be bad for the environment too. In Cambridge we boast leading researchers in environmental management, climatology, sustainability and energy efficiency, but are we listening to them and taking enough responsibility for our environment? In a recent study, People & Planet, a student campaign group, ranked all universities in the UK for good practices by considering their environmental policy, carbon emissions, recycling and other initiatives such as ‘green’ travel plans that encourage cycling and car sharing. The University of Cambridge was ranked a
is, by “ Science its nature, an
energy-expensive endeavour
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respectable eighth, equal with a number of other institutions including our neighbours, Anglia Ruskin University—a considerable achievement considering the difficulties posed by working on a historic campus (Oxford came 27th), which restricts new constructions and the rejuvenation of older facilities. But the
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potentially massive environmental cost of our research is still a cause for concern. The University’s current practice certainly has many positive points to tackle these difficulties. Although our carbon dioxide emissions for 2005-2006 totalled nearly 58,000 tonnes, our electricity currently comes from emission-free hydroelectric generators. We also recycle 230 tonnes of paper, 200 tonnes of cardboard, 12,000 fluorescent tubes and 2000 redundant IT systems. Despite these extensive measures to reduce our environmental impact it remains to be seen whether the message is filtering through to individual laboratories. Science is, by its nature, an energyexpensive endeavour. An article in Nature recently estimated that over a year the average fume hood consumes as much energy as three households. An ultra-low temperature freezer, used across the biological sciences and clinical medicine, costs ten times more to run than its domestic counterpart. In many departments, computer simulations also run through the night, soothed by gentle airconditioning to prevent overheating. It is easy to forget that we have already burdened the environment even before we start the day’s experimentation. Pressure to make full use of expensive laboratory equipment also leads to high energy expenditure. However, it is possible to run laboratories efficiently. For example, equipment at the Magnetic Resonance Research Centre on the West Cambridge site, runs nearly 365 days a year, but,
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according to the University’s Energy Office, it is one of the University’s most energy efficient buildings. With the responsibilities and time pressures on our research group leaders, the impetus may have to come from within our labs to change by example with a common work ethic. Support comes from the University, which has had a full-time Environment Officer since 1995 who gives advice to staff and students about policies on environmental issues—promoting environmental sustainability, conserving and enhancing natural resources, and preventing environmental pollution—but without hindering the experiments necessary to fur-
“mayConsideration benefit more than just the environment
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ther our research. The advice begins with common sense measures such as reducing the volume of print-outs and turning off non-essential equipment, computers and lights at the end of the day. Just turning off the monitor but leaving the rest of the computer running reduces energy expenditure by two-
Michaelmas 2007
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thirds. Moreover, with an estimated 35,000 computers in the University, switching every non-essential machine off at night could save up to 530,000 kW electricity per week, adding up to approximately 12,000 tonnes of carbon dioxide per year. Careful consideration of how we use equipment may benefit more than just the environment. The generally accepted practice in molecular biology of cooling polymerase chain reaction (PCR) products to 4°C after thermocycling is as damaging to the PCR machine as it is to the environment. Stability of the products is unaffected by leaving them at 10°C, but this dramatically reduces the energy consumed and extends the working life of the machine. In the Cambridge Institute for Medical Research, half of the labs surveyed had already changed to the increased temperatures—up to room temperature in some cases—but many had not been aware of the damage done to the equipment until routine servicing had brought up the issue. New scientific facilities are getting in on the green act right from the start. Guidelines from the Environment Office and the University’s Estate Management and Building Service also cover the construction of new buildings. New projects must take into account not only the environmental costs of the construction materials but also the running and deconstruction costs.The new wing of the Magnetic Resonance Research Centre, a shining example that opened last year, combines features such as motion-sensitive lights and external, heat-deflecting blinds in a bid to reduce wasted energy. Even those responsible for purchasing consumables can consider the environmental impact during the decision making.There may not always be an alternative, but wherever possible, laboratories could favour companies with recyclable components, green manufacturing poli-
cies and sensible and returnable packaging. Some chemical suppliers, Fisher Scientific for example, have taken some responsibility for the incredible amount of waste produced by scientific institutions and are reducing the use of nonrecyclable materials such as polystyrene and taking back empty bottles and cardboard packaging. Several life sciences companies, including Promega, New England Biolabs and Sigma, even send their products with return labels for the packaging. We have a powerful voice with the companies supplying our labs—expenditure for consumables with Fisher Scientific in one institute alone exceeded £35,000 last year. Failure of these companies to improve their green performance could result in the loss of valuable custom. The University recommends suppliers with green credentials. For stationary they favour Office Depot who have a directory containing green alternatives to all kinds of office
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items. The Environment Office is also working with them and others to coordinate deliveries in an attempt to reduce emissions resulting from the many delivery runs made to the campus every day. Careful initial purchase and sensible use of equipment are not the only ways we can make a difference. Since July of this year we have become obliged by the Waste Electrical and Electronic Equipment (WEEE) directive to dispose responsibly of equipment, whether functional or not. This may involve appropriate disposal or passing equipment on to another organization. Microscope Services will try to match your surplus equipment with those who need it. For example, they send microscopes and their spare parts to schools and recently to universities in Romania, where they have very little modern equipment. Another potential source of energy and financial cost is the disposal of waste chemicals. Ordering the minimum amount of the chemical required is by far the simplest way to minimise the cost, financially and environmentally, of the disposal of hazardous materials. Information and guidelines, from recycling to waste disposal, are readily available to us through the Estate and Management Service or through the Environmental Co-ordinator of your department. To keep us updated, the Environment Office publishes the Greenlines bulletin several times a year, briefly outlining any changes that may be relevant to your work situation. If we can take a little time to incorporate a greener attitude to every facet of our working lives and encourage this ethic, slowly we can change our little bit of the world. Dr Joanna Baxter is a postdoc at the Cambridge Institute for Medical Research
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A D ay i n t h e L i f e o f …
A Day in the Life of the Chief Scientific Advisor to HM Government Chloe Stockford visits Professor Sir David King to discover what being one of the country’s most powerful men in science entails David King was appointed Chief Scientific Advisor to HM Government in 2001. In this role he has, in particular, raised the profile of the dangers of climate change. In addition, he is the director of the Surface Science Research Group at the Department of Chemistry at the University of Cambridge, where he was formerly Head of Department. He was born in South Africa in 1939 and immigrated to the UK during the Apartheid era. In the week of Tony Blair’s departure from Downing Street, we visited Professor King in his Westminster office.
David King
doing something about it? And if you do something about it you get into trouble. I also became president of the Association of University Teachers in 1977; that was also very political.
What does your job as Chief Scientific Advisor involve? My responsibility is to the Prime Minister and the Cabinet for the quality of science advice across the whole spectrum of current issues. What does a typical day involve? Generally I begin at 8am and finish at 10pm. Between 10pm and 8am I prepare for meetings the following day! It’s a big job and it’s very busy. My private office consists of five people—it has tripled in
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I was, I believe, the most hated figure in the United States
size since I started. That’s because, when I arrived, the definition of science was very narrow. I have been broadening this and demonstrating the wide applicability of science. Have you always had a strong interest in politics? That was the reason why I left South Africa! It was very difficult to have lived in South Africa in the Apartheid era. There were very few fence sitters. You were either for or against. And if you were against, this was difficult in two ways: how do you live with your conscience without
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How can the government best use science to make better policies? After the tsunami in Indonesia I set up a group at the request of the Prime Minister to look into what could be done internationally to prevent such large scale natural catastrophes. As a group, we called in representatives from the United Nations and were told that natural disasters like the tsunami happen on a probabilistic basis, and that science can’t predict them. As it happens, seismologists had predicted a tsunami off the Indonesian coast. But why didn’t governments take notice, and why was there no early warning system in place? It would have cost $30 million but it would probably have saved close to 150,000 lives. So why wasn’t that done? Because the UN emergency team doesn’t understand plate tectonics.There is no mechanism in place to ensure that decisions are supported by up-to-date science. My suggestion to the Prime Minister was to
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form an intergovernmental panel that could discuss improving the management of natural disasters.The next step is going to the UN. It takes years to get these things into place. The whole point in this is to say, “No you’re wrong! Science can inform!” But how do you go about communicating science to non-specialists? Never talk down to people.Treat them as they are: intelligent people that don’t have your private terminology. Explain complex things without dumbing them down, but using everyday language.
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It seems that communication is a key skill in your job. That’s definitely true. In terms of newspaper column inches we have doubled the amount of science topics in the broadsheets in a two-year period. My mantra is “Openness, Honesty and Transparency.” This isn’t always easy because the advice I give to the Cabinet also ends up in the public domain. One criticism of science graduates in this country is that we are not well-rounded enough. Do you agree? I think the way that we specialise after GCSEs in this country is damaging to education.You specialise at a remarkably young age, when it’s difficult to make the right decision. Often children are influenced by one good teacher, not necessarily by their own abilities.The British education system is far too narrow—the International Baccalaureate is better in that respect. Do you think that the media can be irresponsible in misinforming the public about scientific topics? There are examples, such as The Daily Mail and BBC Radio 4’s Today Programme, of the media not always being responsible. They ran a campaign that effectively backed one doctor’s publication that proposed a correlation between the taking of the MMR vaccine and the development of autism in children. Our immediate response when an article like that is published is to fill any information gaps with research. In that particular case, this was done using a Danish study in which 510,000 children were analysed.Those children who had received the vaccine had virtually the same incidence of autism as those who did not, but the newspapers didn’t publish that; neither did the Today Programme. My position is that journalists have an enormous responsibility. You must come under a lot of criticism. How do you deal with it? It turns out that I am very thick skinned, but it also depends on who the criticism comes from. If it comes from
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You have held a number of high profile positions, such as Head of the Department of Chemistry, Master of Downing College, and now as Chief Scientific Advisor to the Government. Which was your favourite? I became Head of the Department of Chemistry because it was a tremendous opportunity. As I saw it, the department
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Cambridge outsider in that I was never a student here.
national forum in which that can take place…but I am working on that!
What would you say was your greatest achievement? I’d say it is still to come. But the most important thing I’ve done to date is pushing climate change issues forward.
Are you sad to see Tony Blair stepping down? I have had a tremendous six years working with Tony Blair. The feedback I’ve had, whilst working on Foot and Mouth disease, obesity or preparing for a possible H5N1 pandemic, has been exceptionally good. I think we’ve made a good working team. In terms of global leadership on climate change and on African development, which have been my two priorities, I couldn’t have asked for more. When Blair put both of those issues at the top of the G8 agenda when we were presidents in 2005, I was delighted.
On a different note, do you think that the £5 billion experiment at CERN is worth the investment? By the middle of this century there will be 9 billion people on the planet, and we will be running out of fresh water. So what about using the biggest brains on the planet to look at desalina-
The most important thing I’ve done to date is pushing climate change issues forward
Catherine Williams
here in Cambridge deserved to be the very best in the world, but there were things that needed to be improved. Helping to raise nearly £50 million to refurbish the place was a big challenge. Being the Master of Downing College was more of an interest—I am a
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tion more effectively? We need to feed the expanding population who also aspire to our standard of living. But the money we are putting into these issues compared to experiments at CERN are miniscule. So I would like to see an analysis of priorities in front of an inter-
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A D ay i n t h e L i f e o f …
people that should be fighting the same battles as me then I am pretty upset by it. I was, I believe, the most hated figure in the United States after I said that global warming was more of a challenge to us than terrorism. I’m quite proud about that.
So Tony Blair has been good for science? Do you think Gordon Brown will live up to these standards? Tony Blair has been good for science and has taken great care to listen to what the science advice has been. But I am very much looking forward to Gordon Brown coming in. I’m certain that he will continue to raise the profile of science. Lastly, what’s next for you? My next career move? I am going to keep up my research in Cambridge.That’s all I’ll say for now! Chloe Stockford is a PhD student in the Department of Chemistry
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Away from the Bench
The Quest of the Ruby Hunter
www.truenorthgems.com
This morning I was woken at six by the thudding growl of a helicopter passing twenty metres over my tent— so much more effective than any wimpy alarm clock. After three summer seasons of field work in remote areas of Greenland, some of them a mere stone’s throw from the ice cap, nothing is likely to get my attention more quickly than the distinctive whop of a rotor blade. Just over two years ago I was midway through my undergraduate degree in the Department of Earth Sciences at the University of Cambridge, when I decided that graduating with little but a selection of cashier and babysitting references on my CV might not be the best of plans. Within a few weeks, I had secured myself a position with a small Canadian company called True North Gems, Inc. And that’s how, a couple of months later, I found myself sitting in a hotel room in Nuuk, the capital of Greenland, with a backpack full of Goretex and no idea what I was doing. Three days later I was dropped off alone on a barren shore with a radio and instructions to “walk between the white rock and the black rock, and look for rubies.” As a result of its complex tectonic history, Greenland, like Canada and Australia, is currently a hotbed of geological and mining activity. Small companies are flocking to remote regions to search for metals and minerals, which was noneconomic 20 years ago. For two summer seasons I worked for True North Gems on their ruby venture in the Fiskenæsset region of southwest Greenland. When I began work on the project, little was known about the ruby deposits there and the company itself was just starting to explore the area. A few
The Kitaa Ruby—the largest ruby ever found in the northern hemisphere
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Meghan Ritchie
Meghan Ritchie searches for treasure on the world’s largest island
Meghan Ritchie in a remote area of Greenland
years ago, the majority of the world’s most prized rubies came out of the Mogok district in Myanmar (formerly known as Burma), an area under martial law and rife with corruption and chaos. In 2003, the US imposed a trade embargo on Burmese rubies, which put intense strain on the industry to find an alternative source of gemstones. The discovery of rubies in Greenland has the potential to impact the coloured gemstone industry in much the same way that ‘bloodless’ Canadian diamonds have transformed the diamond industry. Ruby is the red variety of the mineral corundum; the blue variety is better known as sapphire. Corundum is pure aluminium oxide and its colour is the result of trace amounts of ‘contamination’ by chromium, iron, titanium and vanadium. Few people know that, carat for carat, ruby is far more valuable than diamond: in fact, the only gem worth more than ruby is the extremely rare emerald. A fine quality ruby can fetch up to $25,000 per carat (0.2 grams), so when I found myself standing on an area of rock much larger than my college room with a surface thickly studded with rubies, each more than one centimetre across, I was a little overwhelmed. My primary tasks for True North Gems were to prospect for ruby deposits, and to produce detailed geological maps of the most significant occurrences, in order to identify potential drilling targets for future years. The deposits individually can seem deceptively small on the surface: some exceptional ones, such as the Aappaluttoq occurrence, are only two metres wide
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and 20 metres long. Finding these in the rocky expanse of the Greenland coast can seem like searching for a needle in a haystack, but there was method to apply to the madness. Using geological maps produced by the Greenland Geological Survey in the 1970s to identify and constrain our prospecting targets, we used
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There is nothing like finding a half-million dollar gemstone laying in the mud
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boats, helicopters and sometimes even our own legs to scour the region for ruby localities. Being an exploration geologist in Greenland is much like being in the North American gold rush of the late 1800s: isolated camps of people eating tinned and wild food and spending long, wet, cold, mosquito-plagued days doggedly pursuing the one lucky strike that could change everything. Young geologists are in high demand, and those willing to camp, fly and hike in the Arctic are finding themselves the subjects of bidding wars between employers desperately seeking to staff their projects. And I can tell you that there is nothing quite like finding a half-million dollar gemstone laying in the mud. Meghan Ritchie recently graduated from the Department of Earth Sciences
Michaelmas 2007
I n i t i at i ve s
The Matangini Project The Schistosomiasis Research Group in the Department of Pathology has studied the disease, a parasitic infection, since the early 1980s. Their work has included extensive field research within affected communities in Kenya and, more recently, in villages on the shores of Lake Albert in Northern Uganda. Without access to safe sources of water, the people living in these areas are at high risk from many dangerous diseases, not least of all, schistosomiasis. Schistosomiasis is a tropical disease caused by one of the five species of parasitic flatworm of the Schistosoma genus. It is prevalent in Africa, the Caribbean, the Middle East and parts of South America and Asia. The disease is carried by approximately 200 million people worldwide, 80% of whom live in subSaharan Africa. The natural host of the
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Schistosomiasis affects 200 million people worldwide
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Schistosoma flatworm is a particular species of water snail, and the parasite is most commonly contracted by wading or swimming in water infested with these infected snails. Parasite larvae emerge from snails daily, and have specialised mechanisms for penetrating human skin. Once inside the human body, the parasite is passively transferred from the blood to the lungs and then to the liver, where the worm feeds on red blood cells and matures into its adult form. Adult worms reside in the mesenteric veins that connect the gut with the liver.
Here, they produce eggs, which elicit a strong immune response by the human host as they either become trapped in the liver or exit the body through the gut wall. It is this immune response rather than the eggs themselves that causes the pathology of the disease. Symptoms depend on the species of infection, and can range from diarrhoea and fever to, after prolonged infection, liver and intestinal damage or severe cystitis and ureteritis, the latter of which can progress to bladder cancer. The worms live in the body for four or five years on average, but can persist for as long as 20 years. Despite having a low mortality rate, schistosomiasis is a seriously debilitating disease. The drug praziquantel cures schistosomiasis with a single dose. This drug, however, does not prevent re-infection by the parasite and so is only a short term solution. As for many pathogens, there is a strong need to find a vaccine to prevent the parasite’s life cycle in humans but, in the meantime, we need to focus on preventing infection amongst people who are exposed due to their reliance on contaminated water. Prevention is best achieved either by eliminating the water snails or by providing clean sources of water. In 2005, Dr Mark Booth, a researcher in the Schistosomiasis Research Group, set up the Matangini Project in response to his desire to take a more practical and immediate approach to tackling this disease. The Matangini Project is now a subsidiary programme of the registered charity Stand Up for Africa, which is committed to eradicating the poverty and suffering of children and young people in Africa. When asked by Dr Booth what would most benefit the Matangini School, a primary school in Mtito Andei, Kenya, the
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Lara Moss describes a proactive approach to disease prevention
headmaster replied that they would like to have a borehole so that the children could have a source of safe and clean water. And so, to provide the communities integral to the research of the Cambridge Schistosomiasis Research Group with a permanent and potentially life-saving ‘Thank you’, the Matangini Project was conceived. The Matangini Project undertakes a variety of fundraising ventures to raise money for the boreholes. A collection of photo-gifts are available, including calendars and mouse mats. All profits from the sale of these gifts go straight to the Matangini Project, as costs are covered by the regular activities of the Schistosomiasis Research Group. All author royalties from Dr Booth’s uproarious book, The Wonderful World of Joseph McCrumble, also fund work in Kenya and Uganda. The book is a diary of the eponymous parasitologist who gets expelled from his local village for accidentally poisoning the entire population of pet rabbits with an experimental drug for a parasitic disease. Thanks to the success of the Matangini Project, a borehole with a water pump has recently been constructed in the playground of the Matangini School. Construction of the next borehole, in Mbeetwani School, should start soon and hopefully many more will follow.
Richard Ward
www.standupforafrica.org.uk www.matangini.org.uk
initiatives@bluesci.org
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Lara Moss is a PhD student in the Department of Pathology
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History
Cambridge Tuning into the Universe
The Arcminute Microkelvin Imager Small Array—the MRAO’s latest telescope
Cygnus A.A second survey (dubbed 2C), undertaken using the 81.5 MHz Cambridge Interferometer, was published in 1955. The 1C and 2C results were considered by other radio astronomy groups to be controversial, because the numbers of sources of different luminosities implied that there were substantially more sources in the early Universe than at the present time. This could only be explained by assuming a cosmological model in which the Universe was expanding from an initial singularity—the Big Bang model.The later 3C observations, made with the Cambridge Interferometer at 159 MHz, were more widely accepted and confirmed Ryle’s earlier conclusion that the ‘steady state’ model of a static Universe— advocated by Fred Hoyle, Tommy Gold and Hermann Bondi—should be ruled out.The personal tension between Hoyle and Ryle was national news.
Cavendish Astrophysics
England, 1940. Five miles outside Cambridge, an RAF forward storage facility for high explosive and incendiary bombs was supporting aircraft stationed across East Anglia. The facility was known as Lord’s Bridge Air Ammunition Park, and would be supplemented by a mustard gas filling station four years later. Throughout the country, Britain’s bright young things were being enlisted to exploit technology for the war effort. One of them, Martin Ryle, had just finished his physics degree at the University of Oxford and was now helping to develop radar. This secret weapon was plagued by interference—interference that was identified by the British Army scientist Stanley Hey in 1942 to be radio emission from the Sun. Martin Ryle joined the Cavendish Laboratory immediately after the War. Here he built up a group of brilliant physicists in the embryonic field of radio astronomy—a field sparked by Hey’s very discovery of the Sun’s radio emission. Similar groups of war-heroes-turnedastronomers also established themselves at that time at Jodrell Bank near Manchester and in Sydney, Australia. Ryle and company initially set up an observatory at the rifle range just west of the University rugby ground on Grange Road. Research students lodged at Ryle’s house adjacent to the site. The group’s interest widened from the study of the Sun, and they employed the Long Michelson Interferometer—two radio telescopes that work together—at Grange Road to compile the First Cambridge Catalogue of Radio Sources. The catalogue, known colloquially as 1C, was completed in 1950 and detailed 50 radio sources. Many of these extragalactic radio sources were associated with massive, energetic galaxies such as
Kelly Neaves
Jonathan Zwart charts the discoveries of the Mullard Radio Astronomy Observatory
Left: Graham Smith and Martin Ryle building the Long Michelson Interferometer. Right: Antony Hewish with the Interplanetary Scintillation Array.
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The Radio Astronomy Group at the Cavendish Laboratory soon outgrew its home at the rifle range. The Mullard Radio Valve Company, a subsidiary of the Dutch firm Philips, donated £100,000, allowing the group to acquire a new site at Lord’s Bridge near Barton. This location was ideal because it is protected from terrestrial radio interference by hills that create a natural bowl. Nowadays a reflective metal fence
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The personal tension between Hoyle and Ryle was national news
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affords extra protection from the M11 motorway. Thus, two participants in the war were united: Ryle (and others) and the Air Ammunition Park at Lord’s Bridge. The Mullard Radio Astronomy Observatory (MRAO) was opened by Sir Edward Appleton on 25 July 1957, and its 50th anniversary is being celebrated this year. The first telescope at MRAO was the 4C Array, a 450-metre long, cylindrical parabolic array.This ship-like instrument surveyed the northern hemisphere for radio sources with unprecedented sensitivity.The 4C Array exploited the ‘Earthrotation aperture synthesis’ technique whose implementation Ryle pioneered. ‘Aperture synthesis’ uses a number of distinct antennas instead of one dish to collect signals from outer space. It also uses the Earth’s rotation to its advantage as the antennas collect data at a number of different orientations relative to the
Michaelmas 2007
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This was the first ever Nobel Prize to be awarded for astronomy
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remarkable man, who not only provided the inspiration and driving force but actually designed most of the bits and pieces, charmed or savaged official persons according to their deserts, wielded shovels and sledgehammers, mended breakdowns, and kept the rest of us on our toes.” For his observations and inventions, in particular of the aperture synthesis technique, Martin Ryle was awarded the Nobel Prize in Physics in 1974.This was the first Nobel Prize ever to be awarded for astronomy, which Ryle shared with another MRAO astronomer, Antony Hewish. Hewish, who had worked on radar with Ryle during the War, had designed the Interplanetary Scintillation Array (IPS) to pinpoint radio sources that were less than one second of an arc across (less than 1/3600°). Only such small sources would demonstrate the atmospheric ‘twinkling’ to which the IPS was sensitive. In November 1967, Hewish and his student Jocelyn Bell discovered a radio source that emitted pulses of radio waves as regularly as an atomic clock.The pulses were so regular that the pair named the source LGM-1, for Little Green Men. Terrestrial interference was ruled out, other pulsing sources were identified, and within a few months the pulses
were attributed to spinning neutron stars—dense, collapsed supernova remnants with masses similar to that of the Sun, but with a diameter of only about 10 kilometres. A new class of astronomical object, the pulsar, had been discovered in Cambridge, leading Hewish to his Nobel Prize. Meanwhile, the development of aperture synthesis techniques continued with the commissioning of the 5-Kilometre Array in 1972. This was the first Earthrotation aperture synthesis telescope in the world to have a resolution comparable to that of an optical telescope. By now, radio astronomy was big business, with no expense spared: the array was built by Marconi and cost £2.1 million (about £22 million in 2007).The control room contained a viewing gallery for VIPs to watch the scientists at work.The eight individual antennas that made up the telescope were spread out in an almost exactly east-west line, up to five kilometres apart. Four of them were mounted on railway tracks, after Lord’s Bridge railway station and a section of the Cambridge-Oxford line were acquired by MRAO. Being able to move the antennas made the instrument more flexible. The contribution of the 5Kilometre Array and subsequent telescopes at MRAO to our understanding of the substructure and physics of radio galaxies cannot be underestimated. In the 1980s, John Baldwin led a breakaway group of astronomers in applying the aperture synthesis technique to an optical telescope. Although this is much harder, because the antenna positions must be known to a fraction of a much shorter wavelength, it is possible to obtain resolution as good as that of the Hubble Space Telescope from the ground. The Cambridge Optical Aperture Synthesis Telescope was the first optical interferometer in the world. Many technical challenges have since been solved, permitting optical interferometry to become a more widespread method in the 21st century. In 1984, Mark Birkinshaw and Steve Gull detected another phenomenon for
the first time: they noticed that the amount of cold microwaves—the afterglow of the Big Bang—detected when looking in the direction of a cluster of galaxies is lower than expected.The explanation was that the photons in the microwaves gain energy en route to the Earth by scattering off gas around the galaxies. This was named the SunyaevZel’dovich (SZ) effect, after its discoverers. The 5-Kilometre Array was upgraded in bandwidth at this time, and renamed the Ryle Telescope after his death in 1984. In 1993, it was the first instrument in the world to image a cluster of galaxies, Abell 2218, using the SZ effect. Once again MRAO astronomers were leading the way. The modern Cavendish Astrophysics has a diverse research programme. The Cambridge surveys to date have completed as many as nine catalogues of radio sources. The Ryle Telescope has recently become part of the Arcminute Microkelvin Imager, an SZ survey telescope at Lord’s Bridge. Other important cosmic microwave background observations have been made with the Cosmic
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They named the source Little Green Men
History
object being studied as the Earth spins. This provides a much clearer overall picture and is the only way that much radio astronomy can be done—a dish as we would conventionally think of one might need to be five kilometres across to produce similar results. According to the eminent theoretical astrophysicist Peter Scheuer (1930–2001), the development of aperture synthesis “was the story of one
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Anisotropy Telescope, also at Lord’s Bridge, and the Very Small Array, assembled at MRAO and sited in Tenerife.The group is an active participant in the Planck satellite mission—launching in 2008 and precisely measuring substructure in the cosmic microwave background—and in the next-generation radio observatory, the Square Kilometre Array, to name but a few. Lord’s Bridge will be integral to developing and testing technology for the latter in particular. And all around stand beautiful historic telescopes amongst 300 acres of historic bomb bunkers. A new Kavli Institute of Cosmology in 2009 will be followed by the co-location of Cavendish Astrophysics with Hoyle’s old group, the Institute of Astronomy. Although neither Hoyle nor Ryle would have approved, the combined clout makes this a shrewd move for both groups. The fusion of technology and hard work has allowed MRAO to make some astonishing discoveries in its 50 years. But to leave it at that would be to dismiss out of hand the rich tapestry that is its protagonists, its character, its history and its beauty. Many happy returns, MRAO— and here’s to the next fifty.
Jonathan Zwart
A podcast of Prof. Malcolm Longair’s lecture, “A Celebration of 50 Years of the Mullard Radio Astronomy Observatory at Lord’s Bridge” is available at www.bluesci.org The Arcminute Microkelvin Imager Large Array. Four antennas are mounted on the railway.
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Jonathan Zwart is a postdoc at the Cavendish Laboratory
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Arts & Reviews
Science Blogging Weblog 1: Introduction Unless you have not used the internet in the last four or five years, ‘blogging’ is a term that you cannot easily have missed. Its popularity has exploded in recent years, with diverse groups of people using the forum to write and publish on a bewildering range of topics: politics, fashion, personal thoughts, travel and more. Readers are able—and encouraged—to leave feedback on what they find. More recently, an unlikely crowd has taken to blogging: scientists are now using the medium to write in an informal style about topics beyond their narrow window of expertise, and to discuss ideas that may not conform to the desired style and content of peerreviewed journals. Alongside podcasting, this is the latest development in science communication, and enthusiasts are realising that blogs are an excellent medium for presenting their work. Science blogs are defined either by their subject or by the experience and position of the author; that is, whether they are written by a practising scientist,
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Seeing the paper in print does not mean that the work is over
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Sanne de Wit
a student, or perhaps a science journalist. Thus, many different kinds of writing are lumped together under this amorphous title of ‘science blog’; but as their number grows (and there may be around 1000 in the English language already) distinctions will arise: science teaching (including classroom) blogs, popular science, science & politics, ‘life in the lab’, and ‘open lab notebooks’ may all become recognised genres.
Weblog 2: The reliability of blogs We are constantly fed the idea that internet sources are untrustworthy, and undoubtedly a critical approach is essential to matter published in cyberspace. But what we often forget is that the reliability of newspaper or magazine articles cannot be guaranteed; nor can we rely absolutely on the accuracy of scientific papers published in peer-reviewed journals. Indeed, a non-negligible number of papers are subsequently retracted or are found to be plagiarised, including several recent high-profile instances, such as that of the disgraced South Korean scientist, Dr Hwang Woo-suk. However, it typically takes some time for a community of experts to demonstrate that a published article is fallacious. Blogging trumps traditional media in this respect since it can speed up post-publication discussion due to the ease of leaving comments or posting counter-arguments. And just as conventional publications exist in a hierarchy of authority, blogs can be assessed for their provenance: a reliable blogger will not just experience a high number of hits on his site, but may also be ‘blog-rolled’, where unrelated websites advertise the blog and include a link to it. Some red flags are obvious: bad spelling, bad grammar and a lack of links to supporting documents. However, most science bloggers are good writers, and routinely refer to peerreviewed literature. Weblog 3: The future of blogging Science blogging opens up the subject to the public in a number of ways. Firstly, it shows scientists to be human, countering the stereotype of mad, analytical and humourless researchers. It translates ‘scientese’ into a language understandable to a lay audience, and can demonstrate the excitement of science in realtime. Blogs also provide a venue for nonscientists to interact directly with scientists on a regular basis.
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Galileo Galilei was mocked, and not just for his name
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Sanne de Wit
Mico Tatalovic and Bora Zivkovic explore the future of science communication
“Some red flags are obvious” Secondly, it opens up the publishing process. With an increasing number of open-access journals, the introduction of online journals that allow comment to be left, and the ability of independent science bloggers to respond to newly published research, the publication of a paper is not the end of a process so much as the beginning. After months or even years, seeing the paper in print does not mean that the work is over. Rather, an idea has been born and then takes on a life of its own.This could lead to an improved quality of work: criticism can be lodged more readily, demanding more clarification of the results. Additionally, some laboratories are now ‘weblogging’ their less interesting or negative results online, thus pushing otherwise unpublishable—yet useful—data into the public domain. Finally, blogging may foster collaboration. There is a misconception that the world of science is one of cut-throat competition and dark secrecy. This may provide for good stories in films. In practice, however, this might be the case in a couple of prominent areas of research, but for the most part, people are eager to share and collaborate. Scientists are more likely to be excited about each others’ research than threatened by it. With faster and easier communication provided by the web, rather than being afraid of getting scooped, scientists may link up with others who have similar interests, to exchange ideas and notes, and possibly to carry out and publish research together. This is particularly beneficial for researchers outside elite institutions in the USA and western Europe, who cannot rely on local funding and infrastructure.
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The anthology showcases the quality and diversity of science blogging
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interested groups—science bloggers, working scientists who knew very little about blogs, professional science journalists, and science educators.Their goal was to teach and inform each other about what they want from the internet, their expectations of each other, their strengths and expertise, and how they can work together to reach those goals. The conference generated many
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novel ideas, and its success will be built on by a second one to be held early next year. Zivkovic says about his newly published book of blogs: “The anthology was designed to complement the science blogging conference, aiming to showcase the quality and diversity of science blogging.” The two media are different—parchment and pixels—so the articles included in the anthology are out of their original context: they are standalone articles, whereas blogging is realtime communication. The book has been well-received, and nominations for the second edition are currently being accepted. The hope is that more nonbloggers will read it and see that blogs are not just personal diaries, but can serve to communicate high-quality and often fun reports.
Sanne de Wit
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Arts & Reviews
Weblog 4: The first science blogging conference and anthology Bora Zivkovic, a Serbian-born PhD student from North Carolina University, organized the first science blogging conference, held this year. He also writes his own blog, and has compiled and edited the first science blog anthology. The blogging conference was born out of the desire of a group of science bloggers “to meet offline and have a beer!” says Zivkovic. It gathered four
The conference was a big success Weblog 5: Where to blog, how to blog, why to blog. “Go slowly,” advises Zivkovic. “Start reading first.” A logical starting place is Seed Magazine’s scienceblogs.com which now has 61 blogs, including some of the best to be found. You can expand your reading list further by following the links and blog-rolls outside the Seed Science Blogging universe. “Next, start commenting. Observe the rules of
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etiquette. Check the standard of discourse.Then, if you feel that you have a voice and something original to say, start a blog of your own and tell others about it!” www.scienceblogs.com/clock/ Mico Tatalovic is a PhD student in the Department of Zoology
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In Brief
In Brief The spotted hyena, a native of the Ngorongoro Crater in Tanzania, is noted for its social groups or ‘clans’. It has long been known that it is predominantly the males of the species that leave the clan to join other social groups, behaviour which minimizes inbreeding.Theories have suggested that this is due to competition within a clan between rivalling males, or a shortage of food forcing the males to disperse in favour of a better standard of living. However, a study published in Nature suggests that the main factor in this male-dominated dispersion is the preference of the female. Female spotted hyenas mate with several different males in one monthly cycle and may not be able to identify her own father. The mate-choice rule states that
the female must avoid males that were members of their group when they were born, and favour males that immigrated into their group after their birth. Rearing the young hyenas occurs over a very long period, and is the responsibility of the mother alone; it is in her best interests to choose a mate wisely. With ten years of detailed demographic data and by observing the behaviours of 426 offspring using microsatellite technology, research groups based in Berlin and Sheffield were able to collect data supporting the female mate-choice method in many different clans in the Crater. This is the first study of its kind to assess the reproductive success of social mammals related to male dispersion decisions. BA
Wikimedia Commons
The Hyenas
A spotted hyena and her two cubs in the Ngorogoro Crater,Tanzania
“Youth! Arts! Science!”
Energy required
Roche, one of the top pharmaceuticals and diagnostics companies in the world, recently invited 99 graduate students from across Europe, including seven from the University of Cambridge, to participate in an exciting oneweek cultural workshop named “Roche Continents— Youth! Arts! Science!” in Salzburg. The workshop overlapped with the famous Salzburg Festival, allowing the students to enjoy fine contemporary musical performances.The workshop was aimed at stimulating the creative sides of young minds: the students learned about arts, culture and innovation, and participated in debates. “It is really impressive how the young participants from different backgrounds can come and work together to present innovative ideas and inspire creativity among others.” Niggi Iberg, the program director for Roche, commented. The participants found the program inspiring and refreshing, enabling them to explore other dimensions of life beyond academia and to promote networking. Roche’s five-year commitment to the Continents workshop will encourage other young scientists to discover the links between arts and science, innovation and technology, academia and industry. SD www.roche-continents.net
Scientists at the Karolinska Institutet, Stockholm, have discovered the first ever mitochondrial factor to repress expression of mitochondrial DNA. Mitochondria are organelles within the cell that function as the producers of the body’s ATP, its universal energy store. ATP is used throughout the body, powering everything from keeping warm to movement. A vital question is how mitochondria can tailor their energy output to match the constantly changing needs of the body. Discovery of the new protein, MTERF3, is a step towards solving this problem. MTERF3 is the first mitochondrial protein discovered to specifically repress production of mitochondrial genes. It has been found to work by binding to mitochondrial DNA and preventing transcription. Thus, proteins encoded by mitochondrial DNA, such as subunits of the mitochondria’s own ATP-producing machinery, are downregulated. By altering the expression of proteins needed for ATP-production, MTERF3 might help to control how much energy is produced in the cell, such as reducing ATP synthesis when less is required. Its discovery may also lead to the development of new therapies for diabetes, Parkinson’s disease, and even ageing, all of which can result from mitochondrial disfunction. MP
Shining a light on drug design A team of researchers at Queen’s University, Belfast, may have found a way to release drugs only where they are needed. The scientists, led by Dr Colin McCoy, have proposed that a technique of lightbased activation of chemical compounds, common in organic synthetic chemistry, can be borrowed by drug designers. In organic synthesis, specific functional groups of a compound can be blocked by chemicals such as 3,5-dimethoxybenzoin
(3,5-DMB). Light of a suitable wavelength can remove the masking agent, re-activating the compound. To prevent the freed masking chemicals from circulating around the body, the drug can be immobilised on a synthetic polymer from which the activated drug could escape but the masking agent could not. Dr McCoy and colleagues showed that three common drugs—aspirin,
ibuprofen and ketoprofen—could be inactivated by attaching 3,5-DMB. The masked drug was then immobilised in a synthetic hydrogel. They found that it was possible to vary the amount of drug released by adjusting the duration of exposure to light. The researchers suggested that the technology could be used for medical devices that are prone to bacterial infection, such as catheters. SD
SciSoc 2007 This Michaelmas, SciSoc will be holding three special events in addition to its regular weekly talks. On 3 October, we will be welcoming Bjørn Lomborg, author of the controversial book The Skeptical Environmentalist, and one of TIME's top 100 globally most influential people. We are delighted to have secured the hugely popular Simon Singh for an enthralling talk on Cosmology and his new book Big Bang at our ‘Enhanced SciSoc Squash’ on 16 October. And finally, our acclaimed Annual Founder's Dinner will be held on 3 November, with an address by Nobel Laureat,Tim Hunt. DG For more details on these and our other events, log on to www.scisoc.com.
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news@bluesci.org
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Michaelmas 2007
O n t h e C ove r
Faster, higher, stronger...smaller?
Luis M. Fidalgo
How many experiments can you do in a day? If you’re a particle physicist, a single experiment might be hanging on years of preparation and billions of pounds. But, as Luis M. Fidalgo explains, getting those yearned-for results need not be such a time-consuming pursuit. Fidalgo, who took the image on the cover of this issue with his colleague Dr Graeme Whyte, works in the Department of Chemistry where he develops miniature devices in which as many as 1000 reactions can be carried out—each second. His microdevices allow reagents to be mixed together in droplets of a tiny volume. The reagents, which are supplied through separate channels only 50 micrometres in diameter, are mixed within the device. Oil is delivered by other channels and separates the reaction stream into droplets (see diagram). Each droplet represents a distinct reaction whose composition can be altered by changing the flow rate of one of the reagents. But how do you detect which droplet has the most product? “Fluorescence,” Fidalgo explains, “makes detecting products simple.We use specially modified reagents that have fluorescent products.” The green colour in the cover
image is emitted by a fluorescent dye as it is injected into the device. But detection is not limited to fluorescence; efforts towards incorporating other analytical techniques to microdroplets are being carried out both in Cambridge and at Imperial College London. Studies on single molecules and individual cells are also possible using these microreactors.This is achieved by diluting the chemical solution so that each droplet is unlikely to contain more than one molecule. Whilst this necessarily calls for vast dilution factors, Fidalgo remains unmoved: “It doesn’t matter that 80% of the droplets will have no protein at all when you can produce thousands of droplets per second,” he explains. The directed evolution of enzymes is one application of single molecule studies. Enzymes are proteins that catalyse reactions. Being proteins, they are polymers of subunits called amino acids. A whole library of enzymes with a diverse subunit composition can be readily synthesised, with the aim of creating an enzyme with improved catalytic activity. Each droplet in a microreactor experiment of this sort would contain just one enzyme molecule. It’s a simple matter to pick out the best enzymes: any droplets with increased fluorescence due to the presence of an improved enzyme are isolated. After separating them, the exact sequence of the most catalytic enzymes can be determined, and the changes that made them more efficient can be explained. Eventually, this could help us understand how enzymes have been selected through evolution, and which ones are likely to disappear. It isn’t all plain sailing, however. Microfluidics, as this technology is called, has problems of its own. Creating the tiny
A microdroplet reaction chamber photographed from above
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Aitor Mesa
Terry Evans meets Luis M. Fidalgo, the scientist behind our cover image
channels in the microdevices requires the use of microfabrication techniques taken directly from computer manufacturing. And that is not the most difficult part. Existing in a macroscopic world of measuring cylinders and beakers, trying to relate to a world of microchannels and
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1000 reactions can be carried out each second
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microdroplets represents one of the permanent challenges of this technology. “Water doesn’t behave in the same way on the micrometre scale,” Fidalgo explains. “The surface area to volume ratio of these droplets causes the properties of the liquids to change—think of a liquid rising up a capillary tube.” The mind boggling capacity of the microdevices (which dwarfs the notion of ‘high throughput’) is not the only advantage: Fidalgo needs only 200 microlitres of reagents per day. With volumes like that, a teaspoonful of liquid would keep him occupied for a month. Microfluidics technology relies on a fusion between engineering, chemistry and biology. Most of the interest is currently centred on the biosciences, especially directed evolution and chemical biology, but Fidalgo is keen to point out that “anyone with a need for highthroughput might benefit from the microreactor technology.” And with a projected one hundred million reactions taking place per day, who wouldn’t want to downsize? Terry J. Evans is a PhD student in the Department of Biochemistry
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Please email your queries to drhypothesis@bluesci.org for your chance to win a £10 book voucher Dear Dr Hypothesis, I’m a keen climber, and yet I watch with green envy videos of gecko lizards scurrying about on smooth surfaces. How do they do it? Agile Annie DR HYPOTHESIS SAYS: Dear Annie, the effect you’re seeing is the result of a high degree of adaptation in the gecko. Each of a gecko’s toes is covered with millions of tiny hairs called satea, each of which is further split into hundreds of bristles called spatulae. As the gecko places a toe on a surface, each of the tiny spatulae forms a bond at the molecular level with the surface, using tiny forces called Van der Waals interactions.Although weak individually, together, billions of these interactions are so strong that all four feet of a gecko could hold the equivalent of 90 lbs. Now that would be a large gecko! These interactions are of great interest to nanoscientists, who have recently come up with a version that works underwater, called geckel. Hang on in there, Annie—you may yet get some use from this technology yet! Dear Dr Hypothesis, Why do I feel tired after a meal—and work less efficiently? Why does my supervisor experience a post-lunch dip? Could it be due to stomach distension, an increased blood supply for the digestive system compromising brain circulation, hypoglycaemia as a result of over-reacting to the initial rise in blood sugar levels, or perhaps there are other reasons? Kipping Kristjan
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DR HYPOTHESIS SAYS: Well, Kristjan, you’ve certainly given me food for thought! Actually, there are a number of reasons that act together to cause the ‘post-prandial lull’: it costs energy (an increase in metabolism of 25-50%) to digest the food; and, due to digestion, the hormone CCK is released to tell the brain that you’re full while simultaneously activating the areas of the brain involved in sleep. Finally, when you eat lots of carbohydrate the level of tryptophan (an amino acid) in your blood increases, which is converted into serotonin in the brain, and this also makes you sleepy. My only advice to you is to avoid eating a particularly large meal before that important meeting with your supervisor. Dear Dr Hypothesis, My friend recently lost a hand in a potting shed-related accident. What are the recent advances in bionic hands so that he may continue his gardening in the future? Friendly Fred DR HYPOTHESIS SAYS: Dear Fred, your friend is indeed most fortunate—a Scottish firm has just created a new bionic hand. It features fully articulated joints, as well as myoelectrical sensors, allowing the motors to be controlled by thought alone. The artificial joints allow a dexterity of movement never seen before, which gives the patient the ability to grip gently. One soldier fitted with the hand commented that he was now able to hold polystyrene cups again—so a pair of gardening shears should ‘posie’ no problem!
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Think you know better than Dr Hypothesis? He challenges you with this puzzle: How fast could a human run? Please email him with answers, the best of which will be printed in the next edition.
Dear Dr Hypothesis, I’m a keen meat-eater, but I’m worried about the global impact of my diet. How much of a carbon footprint do I leave? Ravenous Ron DR HYPOTHESIS SAYS: Dear Ron, it’s an important question that you ask. Quite aside from the ethical questions about eating meat, there is a real environmental impact associated with being carnivorous. The carbon costs include the production and transportation of feed, the process of calf rearing, and getting the meat from the farm to the shops. A recent study suggested that one kilogram of beef on the table has the equivalent footprint of travelling 250 kilometers by car, as a conservative estimate. Cows also produce a large amount of methane (an important greenhouse gas), but carnivores like to remind us that the personal gaseous emissions of vegetarians exceeds that of their meat-eating friends!
Sanne de Wit
Dr Hypothesis
Dr Hypothesis
Michaelmas 2007
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