Brains, Batteries and Nuclear Fusion

Chris -   I've just met a robot driving itself down a hall pursued by two people, one of whom was wearing a hat covered in electrodes.  The other was Swiss Scientist Jose del Millan...

Jose -   There is a general problem of providing people the capability to control prosthetic devices, like small robot wheelchairs, by decoding the electrical activity of the brain that they can generate spontaneously as they execute different mental tasks related to motor movements.  So this is the general problem.  The specific progress that we are reporting here today is the fact that through appropriate probabilistic methods, we are able to decode when people want to intentionally deliver the command and when they don't want to deliver any commands.  So the robot keeps doing whatever it is doing, for example moving forward or staying stationary in front of a target.

Chris -   First of all, let's look at how you actually use the power of thought to control a robot.  How are you actually doing that?

Jose -   What we do is to record the so-called electroencephalogram, this is done by simply putting in contact some electrodes on top of the head.  Then we are using sophisticated algorithms to find patterns, prototypical patterns of electrical activity in the brain that are associated with the different mental commands that people want to deliver to the prosthetic device.

Chris -   And Michele, you're wearing a hat with all these electrodes on.  How does it work?

Michele -   Well, the hat is very simple.  It's a very light hat.  We use some gel to be sure we provide a contact and by imagining moving my right hand or my left hand I can give right and left hand commands.  As soon as the computer accumulates enough evidence about the fact they're really willing to perform right or left then a command is delivered, and the robot turns, for instance. 

Chris -   So you think 'I want to move my right hand', this changes the activity of certain parts of the brain which is reflected in a change in the signal picked up from the scalp by the electrodes, the computer can decode that.

Michele -   The most important thing is that - what you said is that this process of imaging these movements is really, really easy.  It's really, really spontaneous.  Everybody can do it quite quickly.  We don't need long periods of training actually.  Usually a couple of hours are enough.

Chris -   How do you then translate what the computer hears in terms of the electric signals, into what the robot does?

Michele -   We continuously classify the information extracted statistically then a command is delivered to the robot.  But the robot is smart, so it's not simply executing it.  It has some extra sensors that are designed to allow easier navigation.  For instance, we've put in cameras and we have an obstacle detection system.  The robot tends to dock itself automatically as soon as he understands if it's in front of a person, and we have other kinds of proximity sensors to avoid obstacles automatically.

Chris -   In the real world of course, someone wouldn't be able to think in excruciating detail all the time about the trajectory or the movement they want to make.  So the robot's sort of doing some bits automatically and you can influence them.

Michele -   Exactly.  So it's not that we are competing.  I'm not competing with the robot, but the robot is providing a continuous high quality aid to my task of navigating the environment and I'm interacting with this modality of automatic navigation.

Chris -   How long did it take you to learn to control the robot like this?

Michele -   The first time I tried, when we were building all the system, it took me a couple of hours to be able to control it well, robot wheelchairs, keyboards, whatever.  And it's not just for me.  I mean, I'm here today but we have many more subjects and patients that can actually control the very same devices with very high accuracy, and speed.

Chris - We've probably all had the problem of the rechargeable battery that lasts less and less long after each recharge. Usually it's terminal (sorry about the pun) and the battery has to be replaced, which is not ideal given how much they can cost. But now help is at hand, with the equivalent of an internal plaster for a battery. Here's Scott White:

Scott - In a nutshell what we do is we put things into batteries that make them perform much better and a lot safer. These little things that we put in are microcapsules - very tiny capsules that you can think of as being like 'drugs'. And inside these capsules are special materials that when they get released, make the battery healthy and last longer and be a lot safer.

Chris - When you say "last longer", you're not just talking about how batteries go flat because they've run out of juice, you mean how their ability to recharge and discharge decays with time?

Scott - Exactly, well put. We would like batteries to last ten years. But they don't because of the charge and discharge cycling that we do to them.

Chris - What's actually happening - if I were to zoom in inside the battery with some kind of very powerful microscope and I could physically see inside the battery at a molecular level - what's going on to make my batteries last less long as they age?

Scott - There's a lot of things happening. Probably the simplest way to explain it is that there are small cracks that open up inside the battery. So physically, particles are breaking and two layers of different materials are separating. There's all kinds of interesting electrochemical reactions that are undergoing at the same time, but physically particles break, things separate, interfaces build up, and the end result is that the battery can no longer give you the power that you need.

Chris - But all of the ingredients are still in there, and so if you could stop that happening you'd have a battery that did continue to perform well. So what you're saying is that your work is dedicated to stopping that decay happening in that way?

Scott - Exactly. We're giving it a dose of loving medicine when it needs it. So when little cracks open up, we put things in there that heal those cracks so you're battery is like new.

Chris - OK, well could you explain that then in slightly more detail. So you are literally doping the electrodes with stuff so that if an area breaks it repairs itself. This is, I suppose, like those self-repairing car paints, where there are little capsules of various things, and when they get exposed by the paint being damaged they 'heal' the paint. You're doing the same with batteries?

Scott - Exactly, in fact we started with the very work that you're talking about - self-healing coating, self-healing paint, self-healing polymers. And in those systems we would put microcapsules in that would release a monomer, which is a polymer precursor, that would eventually heal that crack. So now we've translated that technology into batteries. The materials that we deliver to the batteries are of course completely different, they have different intended functions, but it's still predicated on the same thing: we have a capsule with a very thin wall, you can think of it as being like an egg shell, and inside our eggs are materials that will lead to the restoration of battery function. In terms of combating the longevity issue for this battery, we actually deliver conductive particles. So there are conductive particles on the inside of these egg shells that are in suspension, and when the egg shell breaks these particles come flooding out into the area of damage, where cracks have formed, and they bridge the cracks so they conduct electrons, so it restores conductivity.

Chris - I suppose you have to choose the composition of those repair particles very carefully so that they don't participate in other reactions inside the battery, which would be unsafe or, if given enough time, further erode the capacity of the battery.

Scott - Oh absolutely. We have one matre in our work and that is to do no harm, so whatever we put into the battery cannot disrupt its natural performance from the outset. What we do is we give it additional functionality, in this case self-healing behaviour.

Chris - And with this approach applied to a battery, how much better does it become? How much longer can you extend the working life of a Lithium cell?

Scott - Well I can't answer that conclusively yet because it is very new, but I can give you a flavour of how well this works. For example, some of the initial work that we have done on restoration of conductivity shows that within as little as 40 microseconds we get full restoration of conductivity. That's an incredibly short period of time - much faster than a humming bird can beat its wings - and it's 100% restoration of conductivity. Now, what that means in terms of how many more years you could use a battery, I don't know the answer yet. It's still way too new and a little bit far away to be able to predict. My goal is to be able to extend the lifetime by two, three or four times. If you did that, imagine how the economics of electric vehicles would change. We're not talking about replacing a battery pack every three or four years now, we're talking about one battery pack that could last the lifetime of the car or even longer.

Chris - Does this potentially also extend and expand the functionality of the battery? Certain batteries can only do certain things because the current required for some applications would be way beyond the capacity of the battery because they would degrade. So if you could enable them to put themselves right, does that mean that the batteries could be used in more different applications?

Scott - Absolutely. If you push a Lithium ion battery at a very high rate you see degradation mechanisms that kick in immediately and basically they toast your battery. So there's circuitry that's put in to prevent you from pushing the battery that hard. But certainly the battery is capable of doing it, and if this wouldn't hurt it, then you could use it very quickly and also for a long period of time.  Hopefully these kinds of functionalities will be built in to the next generation of batteries and I'll give you everything you ever wanted.

Chris - Scott White, from the University of Illinois

Chris -   The world is united behind a project called ITER, the International Thermonuclear Experimental Reactor. Later this decade, it will attempt to recreate on earth the physics that powers the sun. The aim is to harness fusion power to produce electricity. Brad Nelson is the chief engineer for the US arm of the project.

Brad -   The nuclear power stations we have now are based on the fission process. Heavy nuclei are split to release energy - the famous e=mc2 equation. Whereas fusion occurs on the sun where lighter elements are fused to form heavier elements and to give off power.

Chris -   I suppose one of the problems though is that the sun is a million earths  - the temperature at the centre is really quite high, the pressure is huge, and we're trying to do what the sun does on the scale of a star on the surface of the earth.

Brad -   That's correct. What the Sun uses is gravitational attraction to confine the fuel to create the very high densities you just mentioned. But in reality the temperatures in the ITER reaction will be higher than they are in the sun - about 200 million degrees.

Chris -   This is to make the particles move a lot faster so that they hit each other harder and can get closer together. So you'll get those nuclei to fuse together which the sun does, as you say, by squeezing things very hard with gravity. We've got to do it another way.

Brad -   That's correct. We use a plasma, which is a conducting, high temperature gas that we then confine with magnetic fields, certainly at 200 million degrees there is no material that will withstand that temperature so we must be very careful to keep the plasma away from any kind of wall.

Chris -   So talk us through the process. What chemically will go into the reactor? What will be the process that happens? What will come out, apart from heat and energy?

Brad -   The fuels that we will use in the ITER reactor are deuterium and tritium, they're heavy isotopes of hydrogen. Deuterium is found in sea water. We've heard of heavy water, well deuterium is the hydrogen isotope in heavy water. Tritium is a more unstable isotope which has to be created. In this case, if you bombard lithium with neutrons you can create tritium. And so in future reactors where we want to be self-sufficient in fuel we would have a tritium breeding blanket around the outside of the plasma where neutrons would interact to create tritium and the process would be self-sustaining.

Chris -   And the tritium and the deuterium are fused together to make what?

Brad -   In the reactor the tritium and deuterium are fused together making an alpha particle, or a helium nucleus, which has a fair amount of energy, and then a high energy neutron - 14 MeV neutron. So it's a very energetic neutron, and has some issues with the damaging materials. So materials issues are a big problem, and what ITER's trying to discover is whether the alpha particle, or helium nucleus, which is charged, will remain in the plasma long enough to give off its energy and heat the new fuel coming in and keep the reaction sustained.

Chris -   Can you then talk us through exactly how it will work? So, if I were to set foot in the core of what will be the core of the ITER reactor in the future, what will I see?

Brad -   The ITER is what's called a tokamak, which is a toroidal magnetic device. So imagine a doughnut which you surround with very strong electromagnets, creating a very high electromagnetic field. You first create a plasma by heating up some very rarefied gas inside the doughnut, ionising it, and then you gradually induce a very high current in the gas. In this case, 15 million amps. So we have a plasma, with 15 million amps, inside a very strong magnetic field, and this provides a magnetic bottle if you will that contains the plasma, keeps it in the core of the reactor and away from the walls. We then continue to heat the plasma until it reaches the thermonuclear conditions which allow the fuel to fuse. The neutrons come out, the neutrons hit the wall, and we absorb the power in the walls, carry the heat away - in water in the case of ITER, but in future reactors it would probably be helium. And that power would be used to run turbines and generate electricity.

Chris -   It's being built in France, isn't it? But it's an international project?

Brad -   Yes, it's an international project. Roughly half the world's populations are living in countries where the government is subscribed to build ITER. So the European Union is involved, Japan is involved, the Russian federation, the US, Korea, China, and India are all involved in this effort.

Chris -   And dare I ask the price tag?

Brad - It's hard to say exactly because the countries are providing the equipment for the project as an in-kind contribution. So, rather than all send money and have the project buy the equipment, the parties to the agreement are actually sending the equipment itself. So the exact cost is hard to say, but in round numbers it's something around 20 billion dollars.

Chris -   Two or three LHCs?

Brad -   I suppose that would be right, yes.

Chris -   So, not cheap. But if it does deliver then the future energy savings will be huge. That was Brad Nelson, ITER's chief engineer.

Chris - Traditionally, mouth and throat cancers have been largely associated with using tobacco products.  But in the last 20 years the incidence of these diseases has doubled, especially amongst young people.  Scientists studying the tumours have found an unexpected change - over 90% of them contain the genetic signature of the Human Papilloma Virus - HPV, which is more commonly associated with causing cervical cancer in women.

Scientists think that people having oral sex is spreading the virus to the mouth where it triggers tumours in the same way that it does in the cervix.  Maura Gillison from Ohio State University was one of the first people to spot this trend...

Maura - In 2000, we published the first compelling research that HPV is a cause of oropharynx cancers.  In 2007 we published a study in which we compared the behavior of people with cancers to the behavior of people without cancers.  And we found that oral sexual behavior was associated with risk of oropharynx cancer.  In that study we estimated that an individual with an oral HPV-16 infection had about a 15-fold increase in risk for oropharynx cancer.  The fact that most of these cancers occur in men, we're trying to increase awareness that HPV is not solely a problem for the women of the world.  The men of the world need to wake up and recognise they are also at risk for cancers caused by HPV infection.

Chris - So the same forms of HPV, because it's quite a big family of viruses, can translocate from one bit of the body, be applied to another and be equally pathogenic there?

Maura - HPV is a very unusual virus in that it doesn't travel through the bloodstream.  It's spread by direct human to human contact.  So an individual can become infected in their inner genital region from an infected partner and depending on their behaviors, that infection can also be transferred to the oral cavity.

Chris - What's the evidence that these tumours are now being caused by HPV and weren't before?

Maura - That's a very good question.  What we know from the United States is that as of about 2005, 64% of oropharynx cancers are caused by HPV infection.  We also know that in the United States over the last 20 years the incidence of these cancers has increased by approximately 200%. We do not know, through direct measurement of tumours over calendar time, that that increase is caused by HPV in the United States. However, our colleagues in Scandinavia have shown from their tumour banks, that in the 1970's, about 23% of tonsil cancers in Stockholm had HPV in them and by 2005 that had increased to 93%.  So a 70% increase over a pretty short period of time.

Chris - What if something else was making the cancers happen in the mouths of the individuals who are affected and those cells, being abnormal, are more vulnerable to getting infected with HPV?  If people are just having more oral sex which is transmitting it, maybe the effect you're seeing is just because the HPV sees more cells it can infect so you detect it?

Maura - I think the question you're asking me is, is there any evidence that HPV is there but not really the cause?  We've been able to demonstrate that the HPV is very specific to the tumour and the tumour and the virus have what's called a clonal relationship.  If you look at each tumour cell, it has the HPV in it and it's often integrated into the genome and integrated in the same place, indicating that there was one preceding event and then that clonal outgrowth turned into the tumour.  We can look at it also visually, because we've now developed very sensitive techniques for looking actually for the presence of the virus specifically in a tumour and we can create these beautiful pictures of the pathology showing HPV in the nucleus of each tumour cell and not anywhere else in the surrounding normal tissue.  So it's now accepted that the virus is indeed present in the tumours, its causal and its not just a passenger or coincident infection.

Chris - Why has the rate gone up so much in men but not in women?

Maura - That is the multi-million dollar question of the hour.  We really don't understand why that is.  We do know from women that hormonal influences do dramatically affect what happens to an HPV infection in the inner genital canal.  So given gender is really the most profound hormonal difference in humans, we really do wonder whether or not the natural history of infection may be different by men and women.  The alternate explanation is that sexual behavior differences in men and women may account for it.  In support of that are all of the studies we've done to date looking at infection.  Men have about a 3-fold increase in risk of oral infection compared to women and that's about the ratio of men:women with cancer, 3:1.

Chris - Do you think men being circumcised makes a difference?  Because it protects the female partner against cervical cancer, so if the person is shedding less HPV because they're circumcised, it might mean their partner is less exposed?

Maura - That's a great hypothesis.  It's clear from research now, both from randomised controlled trials and observational studies, that men who are circumcised have fewer infections and are less likely to transmit those infections to their sexual partners.  But all of those outcomes have been through genital infection.  We don't yet have any data showing that women who have partners who are circumcised versus those who are not are at reduced risk for acquiring an oral infection while performing oral sex on either a circumcised or uncircumcised man.

Chris - What about prevention?  You've identified there is a problem.  We can screen for these viruses to a limited degree.  What about the vaccines and things like that?  Are we in a position to do something about this?

Maura - I've been very interested in trying to find out if the currently available HPV vaccines could prevent oral HPV-16 infections.  No one in the field believes that you can get an oral cancer caused by HPV-16 without having a preceding infection.  So, if you could demonstrate that the vaccines were effective in preventing an individual from acquiring an oral HPV-16 infection, then its logical to believe then that that person would be prevented against oral cancers.  Unfortunately those studies that have been planned were cancelled.  It was a business decision on the part of the vaccine manufacturers.  So I think at this point, what we'll have to do is observe populations like in Australia where the government recognise these vaccines as potentially important as cancer prevention.  They made a very aggressive decision to vaccinate boys and girls in schools and did so with tremendous efficiency.  So now in the target age range about 80% of Australian girls and boys in the vaccine targeted age have been vaccinated.  So I think at this point we're going to have to get information on how the vaccines might reduce oral cancer through passive observation over the next 15, 20, 30 years.  Hopefully what we'll see in Australia is they've made an excellent decision for the prevention of oral cancers in boys and girls.

Chris - Let's hope so. Maura Gillison, from Ohio State University.