This week, we hear how one of the brightest lights in the Universe is helping scientists to build better jet engines, fight off antibiotic resistant bacteria and read the biochemical make-up of long-dead dinosaurs. Plus, how fears and phobias can pass from parent to child in a smell, why first impressions really do count, and also the physics of being a lead guitarist...
In this episode
01:07 - What does your face say about you?
What does your face say about you?
with Tom Hartley, York University
Helen of Troy apparently had a face that launched a thousand ships. And scientists say that we form an impression - by looking at the face - of what someone is like in less than a tenth of a second. But what features do we base these opinions on? By studying thousands of faces and peoples' reactions to them, scientists at York University have now produced a computer programme that can tell us how another person will respond when they see us. Which apparently could come in very handy in job interviews or even on dating websites! Tom Hartley led the research and spoke to Chris Smith...
Tom - When people look at a face, they start to form an impression about the person that they're looking at. So, they'll first of all be able to judge things like age and sex, maybe more objective features. But also, they form an impression about more subjective qualities. So, things like whether somebody is approachable or confident, healthy, aggressive - people can guess who's going to win the election based on what their face looks like. Another example would be court cases. So, there's been some work to show that the result of a court case can be determined by the face of the person that their looking at.
Chris - So, how did you try to approach this? What did you do to try and find out what the key features were that people, when assessing a face are actually looking for?
Tom - Well, what we had was a large collection of faces, just ordinary images drawn from the internet. We looked at all of these images and we went through them very carefully and placed 179 points all around the face to sort of form a join-the-dots-like picture that describes the whole face.
For the same pictures, we also asked judges to look at these pictures and tell us what do they think about the person so we would say, "Is this person approachable? Is this person aggressive?" We got 16 different ratings for each one of the thousand faces. And then what we really wanted to do was look at the relationship between the join-the-dots picture of the face on the one hand and the social impressions on the other hand. So, to do this, we trained a computer model to guess what somebody would say about the character based only on information about the shape of the face. We're able to show that just by training the computer, we could get fairly accurate guesses about what people would then say about the person's character.
Chris - Does it work? Can you take a person standing in front of you and get the computer to make a prediction about what the general public would say about that person?
Tom - Yes, as far as we can tell, it works. I mean, we know that it will work quite well from this, what's called a cross validation procedure where we train it on one set of data and then test it on another set. It does seem to work when we try out on our own pitches, we get ratings that accord with our own subjective judgement. And for future work obviously, it will be great to demonstrate this by using a whole new set of faces and finding out exactly whether the model's predictions accord with those that we have.
Chris - Do you think that it would be possible to take this sort of readout and use it to give feedback to a person because obviously, it's very difficult to change the face you have? People often say, "I've got a perfect face for radio." Perhaps we won't go there. But the point is, could I be given some feedback by your system that would help me to adjust the way in which I put a facial expression or the expression I tend to adopt to encourage me to generate greater sensations of trustworthiness amongst the people I deal with or a better friendly interaction with people for example?
Tom - Yeah, that's absolutely right. I mean, that's one of the most important implications of the work really. But one of the interesting things about what we found is that many of the features that vary and contribute to our social impressions are features that will not be the same in one image in the next - for example, approachability or trustworthiness, being signalled by a warm smile. Well, a warm smile is something that might be there in one photograph and not in another photograph. So, the first step if you want to appear to be more trustworthy is to have a photograph with a warm smile. The model can tell you exactly which photographs look the warmest, the most approachable, which evoke which impressions of dominance, which evoke impressions of attractiveness. And so, you can select images that either maximise all of those things at the same time which would be fantastic I guess or maybe you can pick images that are right for the particular purpose that you have at the moment.
So, if you were going to submit your picture for an online dating agency, you might be more concerned about appearing to be youthfully attractive. But if you're applying for a job and you're attaching your picture to a CV, maybe dominance and trustworthiness are more important. And so, for different situations, you might want to use a different picture to portray a different social impression. We now have a really good handle on what it is about these images that create those impressions. So, we've put this kind of instinctive knowledge onto a more scientific footing.
Chris - Tom Hartley from the University of York. He published that story this week in the journal PNAS.
07:08 - Cannabis rewires the brain
Cannabis rewires the brain
with Michael Bloomfield, Imperial College Longon
New research has shown that long-term marijuana use rewires the brain, making it less sensitive to a feel-good chemical called dopamine, and leaving users at risk of becoming depressed and demotivated. Hannah Critchlow visited the British Association of Psychopharmacology 2014 meeting to speak with Michael Bloomfield from Imperial College London...
Michael - Dopamine is a really interesting chemical in the brain that does lots and lots of things. One of the things that it does is send a signal within your brain when something exciting potentially is about to happen, something rewarding. And so, it's involved in motivation. Now, we found within cannabis users that there was a correlation so, a relationship between their motivation levels and their dopamine levels. What we found was that the lower their dopamine levels were, the more unmotivated that they felt.
Hannah - So, your brain lights up with dopamine and reward when you're feeling things of pleasure and when you're getting keyed up to be motivated with something and cannabis actually decreases the amount of dopamine that's in your brain. Is that right?
Michael - What we think is happening is that if you smoke cannabis, that it probably releases a bit of dopamine. When people smoke lots and lots of cannabis over time, the same with recreational drugs that people can use, the dopamine system can become used to being stimulated. And so, it tries to adapt by lowering the amount of dopamine that it makes.
Hannah - How much cannabis would you have to smoke in order to rewire and alter your dopamine pathways in the brain?
Michael - In our study, all of the cannabis users were quite heavy cannabis users. So, most cannabis in the UK is sold as 1/8th which is 1/8th of an ounce. That's roughly 3.5 grams. The cannabis users in our study was smoking a quarter of an ounce of cannabis a week which is quite a lot. So, we're talking about, at least from this study, quite heavy use. I think more work needs to be done to answer that question. I think the other really interesting thing is, increasingly, we're understanding bit more about the different chemicals in cannabis. So, there are probably almost a hundred different chemicals in cannabis. Depending on the balance between these, that they probably have different effects on the brain. So, there's one called THC which is the main one and another one called CBD. What we think is really important is, it's the balance between these as to the effects that they have on the brain in the short term but also the long term.
Hannah - So the bottom line then in your studies at least, regular cannabis use, so at least a few times a week can actually decrease or desensitise your brain's reward pathways so that you might get feelings of apathy and lack of motivation?
Michael - Certainly, that's what we believe based on the findings that we have. I think the story is beginning to fit together. Almost half of young people have tried cannabis at some point in their lives. I think that smoking lots of cannabis over a prolonged period of time does seem to have this effect. There is some work that's been done in the past that has looked at educational outcomes and it's found that people who smoke lots and lots of cannabis, and then importantly carry on smoking lots of cannabis can affect how they do at school or university or in their work life, and this might tie into that quite well.
The other thing as well is that there's some evidence that people who smoke lots of cannabis regularly are more likely to get depressed. This is a bit more controversial because it's very difficult to tease out if cannabis is making people depressed or if people who are depressed for example have low mood and more likely to smoke cannabis to try and feel better about it. But also, we know that this chemical dopamine is probably involved in depression as well. One of the key symptoms of depression is not being able to enjoy things. And that's - if anything - the one that people find the most upsetting is they're not able to enjoy things that they used to enjoy. I think it may tie in with that as well, but I think again, needs to do more research into how all these things affect dopamine and how that affects how we feel.
Hannah - And those people who have smoked cannabis regularly, if they stopped smoking now, would the brain rebalance itself and re-tweak itself so that they could feel feelings of joy and reward, and motivation later on?
Michael - Some of the studies that had been done have looked at people who used to smoke cannabis. In those studies, they've only found very, very small defects if any, on the dopamine system. So, what we think happens is that after a period of abstinence that the brain gets back to normal again. And so, I think if people are worried about the amounts of cannabis that they're smoking, if it's having negative effects on them then my advice would be to either stop or at least cut down the amount of cannabis that they're smoking.
11:44 - The Ebola Virus
The Ebola Virus
with Chris Smith, University of Cambridge
This week we've seen reports from West Africa of the worst outbreak of the ebola virus since the disease was first discovered in the 1970s. So far over 700 people have died in Sierra Leone, Guinea and Liberia. Governments internationally have been holding emergency meetings to discuss the threat. Ginny Smith put your questions to Virologist Chris Smith...
Ginny - But what exactly is Ebola? Where did it come from and what can we do to stop it? Chris, you are a virologist. In fact, we've already had a question in from Twitter (@chainG) wants to know what causes Ebola.
Chris - Ebola Ginny, is a virus. It's what we call a filovirus and down a microscope, you see this very thin, they look almost like little straws or tent pegs because they often bend over and tangle themselves up or sometimes even wire themselves up into sort of figure of 8 shape. They're about 18 nanometres. So, 80 millionth of a millimetre across and up to about a thousandth of a millimetre long. When they spread which they do via body fluids of an infected case, or sometimes even via the air possibly which is interesting because we've had a tweet here from Collin Parrington (13:15) who says, "Why do healthcare workers cover their noses with a mask if Ebola is not airborne? Do they think it's potentially airborne?" Yes, we do. And if a person has Ebola then any part of their body is infectious. When they're injured or a needle goes into them to take a sample or when they give fluids or if they're sick or they have diarrhoea, all of these body fluids are infectious and can go up into the air, and a person can get those particles landing on their eyes or in their mouth, and it can infect them.
Ginny - What makes Ebola so deadly? Why are so many people dying from it?
Chris - Well, it's not a human infection, and it's naturally an infection of fruit bats. We've found this since 2005 when a scientist called Eric Leroy did a big trapping exercise in Africa and went and trapped all the animals that he could around areas where there were outbreaks of Ebola actually affecting great apes because it's not just humans who succumb. And they found that when they tested the bats that they caught for antibodies to Ebola and also the genetic material of Ebola, they were positive of both proving that they were both infected and carrying the Ebola virus which is what you would expect of a carrier. And so, it looks like it's bats passing it into other animals and then into people or even directly into people and then you get an outbreak in humans.
Ginny - So, does that mean it's not quite as deadly for the bats.
Chris - Yes and that's why it's nasty for people because the viruses evolve to live in a bat and it's not very good if you kill your host too quickly because you can't pass yourself onto others. You want to maintain a state where your host is infectious in carrying you, but not killing you. But a bat's immune system and a bat's body is very different to a human. We're both mammals, but we're quite distinct from each other. The viruses evolved to outwit the immune system of the bat, but when it gets into a human, it's a massive case of overkill and the virus goes into actually our immune system itself. It attacks cells called dendritic cells, grows in those, but at the same time, triggers the release of huge numbers, or huge amounts, of immune signalling chemicals that drive the immune system absolutely haywire. And at the same time, cause lots of our first line of defence - our lymphocytes - which are the white blood cells that fight off infection. It drives them to commit suicide. And so, you end up with a very, very poorly functioning immune system and the release of lots of inflammatory chemicals that cause your body to go into a sort of shock.
Ginny - So, it's almost turning our own bodies against themselves. Are there any treatments for it?
Chris - At the moment, no and this is the big problem. The only thing we can offer people is supportive therapy. That means that basically, you prop up their failing organs using whatever means you can, making sure people have enough fluids, making sure they have calories going into them, making sure their blood pressure stays up. And also, dealing with the coagulation problem because the shock state that people go into means that they consume all of their owm clotting factors. As a result, there's a high risk of bleeding. One of the characteristics of late phase Ebola is people bleed from every orifice pretty much. Even their tears can be full of blood. So, making sure that doesn't happen by supportive management is the mainstay and ultimately we would hope we can get a vaccine.
Ginny - That was going to be my next question. I've heard talks of a vaccine. Are we far away from that?
Chris - There have been experiments done and scientists in a number of countries including in the States have done various studies where they have taken certain coat proteins, the outer coat of Ebola. They've inserted the gene for that into another harmless virus, an adenovirus that normally causes the common cold. The idea being that you could infect someone with that that when the common cold virus was multiplying, it would also show the immune system what Ebola looks like and you would therefore safely make antibodies against Ebola. So, if you did then catch Ebola, you'd have antibodies that could defend you and protect you.
Ginny - And how far is that away from being able to actually help people?
Chris - Well, it hasn't really been a research priority because until now, Ebola hasn't been a big threat to countries that have the money or the will to want to make a vaccine. This latest outbreak is the largest we've ever seen in the four decades since Ebola was first discovered in 1976. The fact that now, more than 700 people have died, we've got more than 1200 cases and it's affecting people who are going into airports and potentially, within striking distance of western countries. Suddenly the minds of western countries have been focused and it's been made a research priority now to try to develop a vaccine that might work.
Ginny - And how likely do you think it is that it might spread and affect say, us here in the UK?
Chris - Well, I think at the moment, the risk is really small, luckily. I don't think we have to worry straightaway. But the fact is that there are millions of airplane flights happening and people travelling via airplanes all the time. And as a result, you've got very rapid transit between countries and the incubation period of Ebola can be up to 3 weeks. So, it's perfectly feasible for someone to leave a country incubating, but not symptomatic with Ebola, arrive in another country like a western country and then go out, but go about their business becoming infectious and potentially infecting people before we actually know what they've got and therefore, we could get an outbreak. That's why governments have been meeting to discuss various strategies to stop it if that does happen.
17:44 - Driverless Cars
Since cars were first invented, they have slowly been becoming more and more automated- anti-lock breaking and cruise control are now common in most vehicles.
Cars which automatically maintain a safe distance from the car in front, and even which can park themselves are now available for sale. However it is likely that completely autonomous vehicles are still a way away.
Driverless cars use varying combinations of lasers, sonar, radar and infrared sensors to scan the road ahead and around them. Combined with cameras to detect road marking and signs and GPS to navigate, this allows them to build up a picture of the world they are travelling through.
Google's autonomous car, for example, uses 64 rotating laser beams called 'Lidar' taking more than a million measurements per second to form a 3D model that's accurate to the centimeter.
In the future, it is likely that cars will be able to communicate with each other. This means the car could have advance warning of vehicles ahead breaking or changing lane, making it much easier and safer for them to plan their manoeuvres. One of these systems is currently being tested in Detroit.
Better communication will also allow driverless cars to form 'road trains', following each other. This will reduce accidents and traffic jams, increasing the capacity of the roads. The aerodynamic effect will also to improve fuel efficiency by up to 30%.
The National Highway Traffic Safety Administration estimates that more than 90 percent of road crashes involve human error so it is likely that driverless cars will actually be safer than current vehicles.
One of the biggest barriers in bringing autonomous vehicle to market is price. The Lidar, on the roof of Google's cars, currently costs around $75,000. However they hope to have it down to a more affordable price by 2018.
Legal issues are also contentious, as many driving laws will need to be rewritten. If an autonomous car does crash, it isn't clear who would be responsible, so this makes insurance complicated.
20:27 - The smell of fear
The smell of fear
with Jacek Dubiec, University of Michigan
Psychiatrists know that fears and phobias - like being scared of spiders or needles - tend to run in families, and our sense of smell may be playing a part in the process. Jacek Dubiec told Chris Smith more...
Jacek - As a psychiatrist, I often see children of anxious parents that are anxious. So, I wanted to understand how does anxiety, how does fear is passed from parents to children. For that reason, we trained female rats to be scared of a smell. In our experiment, we use a peppermint smell. So, when the female rats were sniffing the smell, we gave them very mild electric shocks to produce fearful responses in these rats. Then we matched them with males and when they get pregnant and delivered their babies, we re-exposed them to the smell in the presence of their newborn pups. We observed that the pups later expressed fear and avoidance of the smell. It was dependent on the mother expressing fear to the smell in their presence.
Chris - How do you know that the mother was actually frightened of the smell?
Jacek - So, rodents that are usually very mobile, they move a lot. When they are scared, they freeze. They don't move.
Chris - When you then tested the pups, was that in the same way? You just presented this smell to them and then you saw them freezing as well.
Jacek - We did actually two behavioural tests. One was exposure to the smell and indeed, we observed that exposure to the smell caused them to freeze. Another test we did, it's a maze that has a shape of the letter-Y, two arms. In one arm, we placed the smell that was triggering maternal fear and in the other arm, we had a neutral smell. What we observed with the pups, they were avoiding the arm with the smell that was causing mother to be scared.
Chris - So, how do you think that the pups are picking up on their mother's fear and then learning to be frightened of the same thing that she is.
Jacek - The pups at 6, 7 days old pups cannot see and cannot hear. So, we hypothesised, the pups learn about maternal fear through smells. In one experiment, we isolated pups from the mothers and we scared the mother and at the same time, through the tubing, we pumped the air from the mother to the pups. That was enough for the pups to learn about maternal fear. We then look at the activity of the brain and we found that the site that process smells were activated and also, another important side of the brain that is known to be involved in detecting danger, the amygdala was also activated.
Chris - So, putting all these together, some kind of smell is given out by a frightened mother. It goes to her offspring and the presence of that scared smell plus whatever the smell is that she's experiencing at the same time tells these youngsters to themselves establish the same fear circuitry in the brain that the mother's got. So, they're frightened of the same thing in the future.
Jacek - Correct.
Chris - But at the moment, you don't know what the chemical is that's triggering this infectious fear response.
Jacek - We don't know, but we have some hints. In earlier studies, researchers isolated so-called alarm pheromone. So, a substance that mice or rat produces when it's facing any threat. Other mice or rats pick it up. We looked at the structures in the pup's brain that process alarm pheromones. We found that these structures were activated.
Chris - Do you think this fear transmission effect can also happen in humans?
Jacek - I do think I believe and I'm kind of almost convinced that it does because we have clinical studies showing that children of parents who, for example have a dental phobia, so have their fear of dentist that these children will likely develop this fear of a dentist too. And there are also other phobias that are transmitted from parents. In this case, I say parents because dads and their emotions matter too. Now, the question is, how these fears are transmitted. We know from human studies that babies are very sensitive to the emotions that mum expresses. One of the well-known phenomena is so-called social referencing with the infant is with the mum or with the dad. A stranger approaches if the mum let's say is smiling, is happy then the baby will welcome the stranger. But if the mum is upset then the baby may be upset, unhappy. So, we know that the babies will respond to emotional communication.
26:02 - The science of playing guitar
The science of playing guitar
with David Robert Grimes, University of Oxford
You're probably familiar with the sound of the electric guitar, which has dominated popular music for decades. But you may be less familiar with the techniques that some lead guitarists use to get expressive, voice-like sounds from their instruments, by subtly bending and vibrating the strings with their fingers as they play. Amateur guitarist and professional physicist at Oxford University, Dr David Robert Grimes, wanted to know more about what's going on scientifically when guitarists make these sounds. Kat Arney was all ears...
David - Any guitarist who plays has these intuitive techniques they use. Now, one of the reasons that guitar is interesting I think to most guitarist is the amount of expression you can get with it. When you're playing something like a piano where pitch is going discreet, you'll go between notes and you'll hit a C or a C-sharp and that's provided the piano a tune correctly, they're the notes you'll hear. When a human voice for example sings, we hit a note, but we shake around it. We put a natural vibrato on which we can control. That makes it quite nice to listen to.
On a guitar, your pitch in a similar way is not discreet. You can actually bend up in the microtones between notes and you can explore that and it gives it a human vocal quality to the guitar. You have to do is mechanistically, you have to manipulate the strings to get this. I think that's the motivation that I started with. I said, "I want to see what's happening from a physics perspective when I do this and why I get this pitch out?"
Kat - So, how did you go about trying to understand what's going on here?
David - The mathematics and physics of stretched strings have been known since antiquity. And I think any A level, or if you're in Ireland, Leaving Cert students will know the equation of the first stretched string which is related to its length and its tension and its linear density. So, I started and said, "Okay, let's see what happens if I'm bending string and readily displacing it from the fretboard." Now, I said, "If we do a force diagram of that and we work out what's happening and what tension forces are being added and let's see what the net result is." That's it. It started as an incremental step by step starting from a stretch string and then applying forces to it to see what the net effects would be.
Kat - So, that would be like a guitarist kind of bending a string up on a fret as they're playing a note.
David - Absolutely and seeing what happens to it pitch-wise when you resolve all the vectors and you add all the tension forces together, what are you left with and what impact does that have on pitch.
Kat - So, what can this model, this mathematics that you've worked at, what can it actually tell us about playing the guitar?
David - I think it was the mathematician G.H. Hardy who made a comment that he was delighted that none of his work will ever be useful. Sometimes I think a description like that might apply to some of my hobby work. But what it can do I suppose that would potentially be useful is, there is an abundance of different string types available to a player. If they want to pick a string for example that doesn't bend much, they might look at - they may do it intuitively - but if they wanted to quantify, they might look at the equations and say, "Yeah, I need a string that's relatively stiff and ideally has a large area and that will stop from bending when I don't want it to." Conversely, if they want to do big Eric Clapton style events, they might go for the exact opposite and even quantify what the best material is, based on these equations if they so desire.
Kat - There's an increasing number of computer programmes that are mimicking different instruments and different sounds. Do you think your mathematics could be useful for those?
David - In theory, yes. I play keyboards as well when I'm unfortunately roped in different bands I play in, and one of the things, if you're simulating instruments, I think most guitarist will notice that when you put the guitar string that you run, it sound diabolical. It's not even passable. I think a lot of us, due to the fact that it doesn't factor in the mechanics of human touch on that and how we explore around the string. So, someone was into digital instrument modelling and they wanted to say, factor in things like bending in the more natural way or even guitarist vibrato which I covered in the paper as well, in a more natural way. They could certainly use those equations for that.
Kat - And finally, who's your favourite lead guitarist?
David - That is a question I wrestle with every day. I see I'm into very non-cool genres of music. So, I mean, I probably would say John Petrucci from Dream Theatre is my favourite guitarist but I have the guys like Brian May I've loved since I was kid and Steve Vai and Joe Satriani. So, to take one of them, it would be like choosing between childre, I just can't do it.
Chris - David Robert Grimes. He was talking to Kat Arney. Who's your favourite guitarist, Ginny?
Ginny - I'm a big Red Hot Chilli Pepper fan, so I really like the guitar work in that or my parents used to play a lot of Eagles and there are some great guitar solos in the Eagles. So, probably one of those guys.
Chris - You didn't pick the Gilmours or the Townshends. I was a bit surprised. You're not The Who or Pink Floyd fan?
Ginny - Not so much. Kind of passed me by.
31:09 - How do synchrotrons work?
How do synchrotrons work?
with Ed Rial, Diamond Light Source
The Diamond Light Source is a synchrotron, which is a form of particle accelerator. It uses a powerful magnetic field to propel a stream of negative particles - called electrons - in a long circular path at close to the speed of light. As the electrons follow the curve of the half-a-kilometre long path they give off beams of x-rays 10,000 times brighter than the Sun, which scientists are able to tap-off and use to study the structures of crystals or jet engine parts and even to read ancient manuscripts! Graihagh Jackson went to Diamond, in Oxfordshire's countryside, to see how it works...
Ed - My name is Ed Rial. I work here as an Insertion Device Physicist. So, I make some of the special magnets here that make Diamond especially bright. Diamond is a series of particle accelerator that accelerate electrons up to pretty much the speed of light and basically, used light like a diamond microscope to really see the very small details of matter.
Graihagh - How is Diamond different from CERN?
Ed - So, CERN is a giant machine in the Swiss Alps and they accelerate particles called protons. They smash those together at massive energies to really look at fundamental sequence of matter and what was going on in the early stage of the universe.
At Diamond, we accelerate electrons and we put them into our storage room and we accelerate them into the light and then we don't want smashing into anything because we want to use the radiation they emit when they go through a magnet.
So, in terms of technology, we're very similar, but in terms of output, we're looking a very different science.
Graihagh - We're currently in the storage chamber and I can see multiple magnets of all different colours and sizes and cooling equipment and so many different wires. But this is only one facet of the whole of Diamond. Perhaps you can talk me through the very beginning of what happens and how we end up here in the storage room.
Ed - The electron will start their life at the centre of the facility. So, you look down at Diamond from the sky, you look at this giant spaceship donut. Inside of the donut, you have a short line and then a small donut, and then the large donut. The electron starts from the beginning of the short line and the electron, they're fired from a heated cathode and they're then traveling at about walking pace. Electrons then travel through their proper tube and this is the linear accelerator. It takes the electron from the initial 90-kilo electron volts up to 100 mega electron volts which is already 99.99% the speed of light.
Once we are at our operating energy, we head out into the main storage room of which we're sat in now in fact. We're just up as looking around of curved tunnel to where the electrons likely enter the main storage room. They then travel around the 560-meter circumference. They then travel in a vacuum vessel and that vessel is threaded through all of our electron magnets in the main storage room.
The magnets themselves are kind of big blocks of steel and that creates just a straight magnetic field that then bends the bunch of electrons and keeps them on the orbit in our ring. It's a little bit like a swing ball set. Once it turn, the swing ball comes around and you hit it with your bat and the electrons regain the energy that they've lost that they've gone around the storage room.
As they get bent, they emit very hard x-ray radiation and also lights down into the infrared. That light, the infrared visible, the x-rays then are sent down through beamlines into experimental stations where scientists do a variety of studies on crystals and other materials to find out their structure.
Graihagh - What happens in the beamlines?
Ed - There was a lot of techniques used here. A lot of beamlines here use crystallography, so they select their energy of x-rays, they will fire them through a small tiny crystal and they'll get a pattern of spots which they can then use to determine the actual structure of the protein or the molecule they're looking at.
Graihagh - So really, Diamond is like a giant microscope that enables you to see molecular levels of a material. So, whilst a regular microscope, that you might get in a lab you can then see cells, you can see a much higher fidelity atoms in the placements of atoms within a material.
Ed - That would be a very broad version brushstroke, there would be an awful lot of computing and an awful lot of science that goes into parts and terminal of these things. We really are standing on the shoulders of many generation for scientists here.
Ginny - Physicist Ed Rial speaking with Graihagh Jackson at the Diamond Synchrotron.
35:28 - Super strong airplane engines
Super strong airplane engines
with Lewis Owens, University of Cambridge
Each year, hordes of researchers visit Diamond to use the facility for their research. It's helping to discover new drugs and improve the performance of jet engines. Lewis Owens, from the University of Cambridge, joined Chris Smith and Ginny Smith in the studio with an experiment to show how they're testing the strength of metals...
Louis - So, most of you will have seen a jet engine on the side of a plane when you're taking a holiday or whatever, and you'll notice at the front that there's a huge fan blade, which effectively sucks air into the machinery and it goes through a series of compresses and chambers and where it's mixed with the fuel and creates very small timed explosion. And at the back of the engine you've got spinning at extremely fast speeds, incredibly high temperatures and under extreme amounts of force - so we need metals that need to be able to withstand these extreme temperatures and pressure conditions.
Chris - So when you say extreme temperatures, how extreme?
Louis - On the order of sort of 15-16 hundred degrees. It is very often hotter than the metal melts at. It is almost the equelvent of putting an ice cube in an oven and trying to keep it as a solid, even when you crank up the temperature of the oven, which most people know is almost impossible.
Chris - Why don't we just run the engine a little bit cooler so that they don't melt?
Louis - Well in fact, this engine, like most engines works on the transference of heat energy into motion. Infact what you find is, the hotter you can run this at, the more efficient the engine is.
Chris - But in order to do that, we need alloys or materials that can withstand increasingly harsh conditions and we don't have those at the moment.
Louis - Yes, at the moment we don't. We use a family of alloys called super alloys because their properties allow them to operate under such extreme conditions. But we're constantly looking for new ways of designing these alloys in order to create the physical properties that we want.
Chris - And how are you doing that?
Louis - So, one of the ways we do it is by using the Diamond Light Source in order to probe and understand exactly how the structure of these alloys works. In fact, most metals and alloys are a type of crystal, built - if you can imagine from a series of Lego bricks effectively that are all stacked on top of each other - but these bricks can often be of very slightly different sizes and then affected differently by the forces that they're put under in the engine. The spacings between these atoms is a billionth of a meter apart so, there's no sort of standard optical way that we can just look at these simply. So we have to use this extremely intense radiation in order to do it, this effect called diffraction, which if you can imagine, if you've ever seen waves going in or out of a harbour, when a wave reaches a small gap, those waves then spread out. We do exactly the same thing at Diamond. But instead of a harbour wall, you're looking at the gaps between these atoms and you're using x-rays, rather than a water wave in order to look at those.
Chris - Because of course, the x-rays are really small and you need to get between the gaps in the atoms which are really small.
Louis - Exactly.
Chris - Now, you've brought along something to show us.
Louis - I've brought along just a very simple little demonstration. What I've got is just an ordinary laser pointer and I borrowed very kindly from Ginny, one of her hairs in fact. So, if I just shine the laser pointer at the hair, you can see that the laser point on the wall produces tiny little spots on either side in a little light.
Chris - Yes, I can see. A nice big green central dot and then lots of little dots to either side of it. So, what is producing those little dots? Why are they there?
Louis - The light on either side is hitting the hair and spreads out on either side. Then the light from one side meets the light from the other side, it either adds together, like if you're adding two water waves you get a much bigger water wave - or they subtract from each other. And so, you get little patches where you see no light. So, you get this alternating pattern , we're probably about a metre and a half away from the wall and the spots are about a centimetre apart or so I'd say. And you can work out exactly what the size of the object you're looking at is from that distance. In fact you can do a simple back of the envelope calculation and work out the human hair is about 100 microns across. I've got two other things here that we could play with which are a CD and a DVD. So, a CD is obviously made up of a series of concentric tracks going around. If you shine the light off a CD...
Chris - Just watch my eyes here! We've got a spot appearing on the wall and then to either side of that spot, about a meter away on the wall, we've got vertical lines appearing in green laser lights. So, what's going on?
Louis - So, this is the light diffracting and producing what we call interference pattern from the individual tracks of a CD.
Chris - And because the hair is much bigger than the gaps between the tracks and the CD, the hair produced gaps or spots of light that were very close together. But these ones are much further apart because the track is smaller.
Louis - As you said Chris, they're now about a meter apart. If you then do the same thing bouncing the light off a DVD ...
Chris - That one's at the door! It's probably 2 meters actually.
Louis - This is simply because the tracks in the DVD are spaced so much closer together which obviously means that you can therefore store more information on a DVD.
Chris - And extrapolating this to Diamond in your alloys, we can actually say, "Well, with very tiny waves of x-rays, you can get into the gaps between atoms and actually work out what the structure of the alloys are like the other ones."
Louis - Exactly and you can imagine that if we're putting an alloy under a force, either compressing it by pushing it together or pulling it apart, we can imagine that those planes of atoms are going to move towards each other or away from each other, and therefore, we can work out how the stresses affect the alloy.
41:50 - Dinosaur detectives
with Phil Manning and Roy Wogelius, University of Manchester
Scientists haven't just been studying the materials that make up today's world. Fossil detectives Phil Manning and Roy Wogelius have been looking at specimens that are over 50 million years old. Incredibly, the original chemicals that were in the tissues when they were alive are still there; and using the Diamond synchrotron it's been possible to detect them and learn about more than just the shape of the Earth's earliest inhabitants. Graihagh Jackson went to the Manchester Museum to meet some of them...
Phil - Just behind me here at the Manchester Museum is this wonderful mounted skeleton gorgosaurus. You're looking at one of the ancestors of tyrannosaurus rex.
Graihagh - And she's quite spectacular. She's maybe 2 or 3 meters high would you say? She's towering over everyone who enters. What's so special about her?
Male - She really had a tough life and it's very easy when you start looking at the front of the jaw to see this horrible bony infection here. When you go back, she's got this huge tumorous growth on her shoulder blade as well. When you go to her right leg, she's got a compound fracture where some which show the small bone on the lower leg is poking out through the skin envelope. She was a mess. What is the reason behind this? It's only when they started prepping away at the brain crests, someone spotted little bony struts which shouldn't be there. Where there should be brain tissue, there were little pieces of bone. It's a very important part of the brain, these bony struts were occupying. It was the cerebellum. This is the motor control centre for this animal.
Graihagh - Well, what have caused this bony growth?
Phil - Well, that's the $64,000 question. What is fascinating with some of these tumours is they are prevalent in rapidly growing youngsters. What do we have here? we have a subadult predatory dinosaur that's showing rapidity in growth and as a result of that, we've got a potential tumour which is very, very similar to what we see in mammals today.
But if it's cancer or not, that's when we have to start looking at other possible signals and that's where we have to start picking apart the actual chemistry of this fossil. Fortunately, we have access to the Diamond Light Source. With it, we can pick apart the dilute traces of original chemistry to that arm, within your body, within my body, a fraction of 1% of our bodies is made up of these crucial trace metals that mediate enzymatic reactions and build the proteins that make you you and me, me. If we can measure those astoundingly dilute concentrations, we can literally look at the recipe of life itself.
Graihagh - Whilst the recipe of life is a tempting prospect, gorgosaurus is yet to go under the microscope. So, how do we know that these trace ingredients still exist? Well, Professor Roy Wogelius from the University of Manchester has already put a fossil to the test. Roy showed me a specimen taken especially out of the lab from its protective tin foil case, just for this report.
Roy - What I've brought down for you to have a look at is a 50 million year-old leaf.
Graihagh - When you say 50 million years, is that before the comet crashed into the Earth and killed all the dinosaurs or is this after?
Roy - So, this is after the extinction of the dinosaurs.
Graihagh - It's remarkable. It's really beautiful as well. Such an amazing specimen.
Roy - The preservation is absolutely amazing. It's a little bit smaller than my hand and you can see very, very clearly that's a fossil leaf. It looks an awful lot like a maple leaf or a sycamore leaf. The edge of the leaf isn't even flat. It's got little teeth on it. There's another thing that's really interesting about this. If you have a look at this leaf, you can see there's this little patterns that form on. In fact, it almost spells out CSI. Part of the leaf tissue is missing. You could see that the leaf has been kind of skeletonised. It means that just the veins are left behind.
What's really remarkable about this, these little things that I said kind of spelled out the letters CSI, if we focus in, they're actually leftover of insect poop. So, this is a life process - a 50 million year-old insect that's left inside this fossil leaf. Most people would think that this was just carbonised remains. There is no chemistry left behind, but in fact, that's not the case. Copper that's in this leaf, it's still organic, just the way that the copper is bound inside your hair, while I'm standing here talking to you. In your case, or in the case of humans, that's a pigment coordinated copper. Here, this is copper coordinated to some chemistry inside the leaf and in fact, the copper that we detect is still bounded exactly the same way in this fossil leaf that's bounded in the leaves of that tree right outside the window.
Graihagh - So, where exactly did you find the metal in the leaf? Was it all over or was it more concentrated in certain areas?
Roy - What's really interesting is that the metals concentrate themselves along the serration tips and we think that that's either, the metal is being put there as a reservoir so that as the leaf grows, there's a little bit of material there, some nutrients so it can grow larger, or it might actually have to do with armouring the tips of the leaves against insect predation.
Graihagh - This all sounds absolutely fascinating but I couldn't help but wonder what this meant in today's world. Do trace metals really matter? I put this question to Phil, back with gorgosaurus.
Phil - It's like a recipe in a cake. If you slice up the cake, you can look at it and say, "Yes, we've got cake." Once you start analysing the chemistry of that cake, you can see the different ingredients which have gone into that baking process to what you finally form. Here, we can pull apart the chemistry of the healing, and we can look at the various ingredients involved at the different stages of healing.
Graihagh - Does that mean that by looking at the bones of dinosaurs, there might be a potential future in how we might better heal ourselves?
Phil - This animal sits perfectly between two organisms we know very well. One birds and the other crocodiles and alligators. If they get a whole leg bitten off in the swamp, they can survive such massive trauma. Birds have this elevated metabolism. So, they've got the rapidity of healing. So, when you see bird, if it has an injury, it does tend to heal very quickly. Here, we've got an animal in the dinosaurs which slap-bang between this rapidity in healing and its remarkable immune system. When you look at animal like this gorgosaurus, she seems to display a suite of trauma that would kill us mammals. But she seems to have the elevated rates to aid and abet the recovery process, but also an amazing immune response which has permitted her to heal structures that would kill you and I. So, if we can look to animals like this and their descendants and ancestors, we might come up with a recipe for aiding and abetting the healing process in groups such as our own, the mammals.
Ginny - Phillip Manning and Roy Wogelius from the University of Manchester.
48:29 - New class of antibiotics discovered
New class of antibiotics discovered
with Neil Paterson, Diamond Light Source
The World Health Organization (WHO) estimates that antibiotics add an average of 20 years to all of our lives. But since the discovery of penicillin in 1928, overuse of these drugs has led bacteria to evolve resistance, meaning certain superbugs - like MRSA and tuberculosis, are becoming untreatable.Scientists are trying to solve the problem by learning more about the structure of bugs themselves in the hopes of finding a new chink in their armour that we can use to attack them. Dr Neil Paterson works at Diamond and he told Ginny Smith about a new class of antibiotic....
Neil - The main difference with the antibiotic target we've discovered is that it's located on the very outer surface of the bacterial cell. So hopefully, any new drugs that target this won't have to cross the cell membrane and enter the cell. And therefore, they're not subject to detoxification by proteins inside the organism or the the efflux pumping which is one of the major mechanisms for bacterial resistance.
Ginny - So, when you detoxification, what do you mean? What are the bacteria actually doing when they evolve resistance to normal antibiotics?
Neil - The main aim of the bacteria is to keep the level of drug below lethal concentration. So, they can achieve that either by binding the drug and preventing it getting to its target protein or they could bind the drug and change its chemical structure, or they could pump it back out. Bacteria have to deal with toxic compounds in their environment on a regular basis. They have these pumps that pick up a wide range of compounds that the cell doesn't want to have inside and they pump it straight back out. That just prevents the concentration reaching a lethal level.
Ginny - How does your new target solve those problems, get around those issues?
Neil - Well, it's located on the very surface of the cell. So, this is the part of the organism that's directly exposed to the host. For it to function, it needs to open up and allow the passage of a lipopolysaccharide molecule and that's a molecule that decorates the surface of a bacterial cell.
Ginny - Could we try and simplify the language a bit because you're throwing quite a few big words out there that I think I'm getting a bit lost and I think our listeners certainly will be? So, if you could just try and avoid using technical terms as much as possible? Should we go back to the beginning of that question? Is that alright?
How does your target solve those problems and avoid being caught up by those mechanisms?
Neil - Well, our target is located on the very surface of the bacterial cell. And because it needs to open to perform its function, we have an opportunity there to interact with that protein without the drug having to enter the cell in the first place.
Ginny - What does it actually do to kill the bacteria?
Neil - So, the protein we've solved the structure of, it's a pore. So, if you imagine a tube a bit like a piece of toilet roll holder, slightly squeezed and it sits within the surface of the spherical cell with an opening at either end. Now, what we've actually solved is a protein complex. So, there are two proteins in there. One sits inside this tube and this protein complex performs the final step in assembling the outer surface of a bacteria. It transports a large molecule through the pore in the centre and then it serves it into the outer side of the outer membrane.
Ginny - So, if you prevent that from working, then the bacteria kind of can't build its coat?
Neil - It can't build its coat and it can't survive.
Ginny - How has Diamond helped you in discovering that protein?
Neil - Proteins are very small. So, the protein we've solved the structure of is approximately 100,000th of a millimetre. What Diamond gives us is, it gives us very intense x-rays which is the sort of wavelength we need to be able to visualise something that small.
One of the main problems we have, of course, is that biological material and x-rays don't really work well together. You get a lot of radiation damage. And because of that, we have to encourage the protein to form a crystal so that we can spread that damage out across many copies of the protein.
Ginny - When you say crystal, what exactly do you mean? I mean, I'm thinking of a grain of salt here. Is that kind of what it looks like?
Neil - It looks very similar actually. All crystals are essentially repeating subunit. So, you have lots of copies of a certain thing, all arranged in the same manner and then built together like lego blocks.
Ginny - So, are there any drugs being developed using this new method?
Neil - Yes. A group in Switzerland have discovered that if they modify a naturally occurring antimicrobial agent, and that molecule is used by mammalian cells to kill bacteria. It looks like a bit like a hairpin and it inserts into the outer membrane. When it reaches a certain concentration, it forms a pore and spills cell contents. What they found is if you modify that, it no longer forms a pore, but it's still lethal. They discovered that it binds to the pore part of the complex we solved the structure of. Now, they've developed that a bit further prior to us, providing the protein structure. And they've got a compound in phase 2 clinical trials that's active against pseudomonas aeruginosa, an opportunistic lung infection. So, what we've provided in there was a structure of the target and hopefully, we can use that to understand how their drug works, how to perhaps allow it to be effective against other gram negative bacteria.
Ginny - So, if this is an entirely new class of antibiotics, does that mean we can stop worrying about antibiotic resistant bacteria?
Neil - Definitely, not. Bacteria in common with the other microorganisms have been engaged in chemical warfare for millions of years. When you look at the penicillins, they were originally from a mould that's used to kill bacteria that were competing for its nutrients.
What a new class would buy us is a good few decades probably of safety, if we're smart with the use of those compounds, we might be able to extend that further.
Ginny - Thanks, Neil. Dr. Neil Patterson from Diamond.
53:13 - Spontaneous human combustion possible?
Spontaneous human combustion possible?
I'm Hannah Critchlow and welcome to Question of the Week from the Naked Scientists. This week, we tackle the burning issue of spontaneous human combustion. Is it possible for humans to spontaneously burst into flames and if so, how? Well, bacteria in the human gut naturally produce phosphine gas, methane and hydrogen. Phosphine gas, also known as PH3, so phosphate attached to 3 hydrogens could feasibly, spontaneously convert to diphosphine P2H4. If this happens, it could ignite the methane and hydrogen fuels in the gut and send an explosion, igniting in our abdomen, providing high temperatures for the burning of the fat on our skin and the clothes on our back. Surely then, this could make spontaneous human combustion a possibility. Over to Dr. John Emsley, chemist and author. He's contributed his considerable spark to the scientific feasibility of such combustion in nature.
John - Spontaneous combustion is seen as a possible explanation for will-o-the-wisp that was flickering lights that can be seen over marshes at night when something appears to ignite methane as it bubbles to the surface.
Hannah - So, the explosive combination of phosphine gas, diphosphine, methane and hydrogen are emitted by the marsh bacteria that live there, eating the decomposing material - these mix, causing spontaneous combustion and a scientific explanation for the marsh folklore of small goblin-like fairies, mischievously leading travellers off the bitten path at night, using light that looked to be shelter. So, back to microbes living in the human gut, could phosphine gas mix with the hydrogen there to form diphosphine and thereby, ignite the methane? If so, surely, this could explain any reported cases of spontaneous human combustion. Back to John.
John - But it seems highly unlikely, why is that? Well, because getting two phosphorus atoms to bond together in diphosphine requires a lot of energy. They didn't see much point in microbes producing this.
Hannah - So, due to energy requirements, spontaneous human combustion seems improbable. But just to be sure, has diphosphine ever been found lurking in our guts?
John - Diphosphine has never been detected in human intestine or gas.
Hannah - Spontaneous human combustion, at least via this chemical pathway looks to be out of the question though. Thanks, John Emsley for setting us straight. We next turn our attention to this.
Neil - Hi. I'm Neil from Glasgow. I find that I can't work with music playing. All my attention is on the music and it distracts me. On the other hand, I have friends who can't work unless they have music, that loud volume blasting through their skulls via their headphones. Why does this difference exist?
Hannah - Music, a concentration aid or a complete distraction. Why do some people find it helpful and others disruptive? What do you think? you can post on our Naked Scientists Facebook page, you can tweet @nakedscientists, you can email email@example.com, or you can join in the debate on our forum which is at thenakedscientists.com/forum.