July
Chemistry World Podcast - July 2012
1:00 - How does your buckyball grow?
7:47 - Performance nutritionist Mayur Ranchordas tells us what Olympic athletes should be eating and drinking
16:50 - Which energy-saving light bulb is best for sensitive skin?
19:15 - Computations on cuprous fluoride will re-write inorganic textbooks
23:11 - Damian Bailey discusses the oxygen chemistry in the brain where exercise starts and end
30:55 - A paper and plastic HIV test - that takes just 15 minutes
34:10 - The textbook 'umbrella' mechanism of an SN2 reaction is complicated by solvent molecules
38:28 - Trivia: How much gold is in a gold medal?
(Promo)
Brought to you by the Royal Society of Chemistry, this is the Chemistry World Podcast.
(End Promo)
Interviewer - Chris Smith
This month, how buckyballs grow and the smallest one made so far; PCR on paper, this is a revolutionary test for HIV, that takes just 15 minutes and happens on a piece of card, and why Olympic hopefuls should perhaps stop for a Starbucks on the way to the track.
Interviewee - Mayur Ranchordas
Caffeine has been researched in sports and exercise in well over 30 years now and the majority of the research seems to indicate that it has a performance enhancing effect regardless of it being team sport endurance or strengthen power.
Interviewer - Chris Smith
Hello I'm Chris Smith and with me for this month's Chemistry World podcast, our Bibiana Campos-Seijo, Elinor Richards and Patrick Walter.
(Promo)
The Chemistry World podcast is brought to you by the Royal Society of Chemistry, look us up online at chemistry world dot org.
(End Promo)
Interviewer - Chris Smith
And we're kicking off this month with some exciting new work on element number 6. Patrick, tell us more.
Interviewee - Patrick Walter
Okay, so what links a candle and supernova? Fact is it's buckyballs. So Buckyballs are these football shaped allotropes of carbons that builds up these hexagons and pentagons into a nice football shape, but the mystery that's been puzzling scientists for some time is how buckyballs grow larger, how is it that you get from a buckyball that contains 60 carbon atoms to one that contains a 76.
Interviewer - Chris Smith
Do you find those sorts of things in nature, then we'll find one with 60 and one with 76 and one with something in the 80s. Do you actually find them?
Interviewee - Patrick Walter
Well yeah, you can see this distribution in candles. So when you light candle you can actually capture the soot coming off and you can get a distribution of all these different buckyballs, so very large ones, much less likely ones like C-60 much more common and the same thing happens around supernova. No one really understood how they're growing, that's been the problem.
Interviewer - Chris Smith
So, what with the theories, presumably a sheet of something like graphene folding in on itself or something to give you a ball from a flat sheet.
Interviewee - Patrick Walter
Yep, that's certainly been one idea but there were certain problems with that and people will never quite show how this could happen, how you could have sheets of graphene in space in the first place.
Interviewer - Chris Smith
Indeed I suppose that is a consideration. So who's been doing this and how did they try to solve it?
Interviewee - Patrick Walter
Harry Kroto, he is the Nobelist, the chemistry Nobelsit of buckyball fame. Okay, so it's. He discovered them. He's at Florida State University in the US. Obviously with the background in buckyballs, he was very interested to try and solve this mystery of how buckyballs grow bigger. So, he investigated this by blasting a source of carbon 60 with a laser and at the same time blasting an amorphous carbon source.
Interviewer - Chris Smith
Which can give you this supply of carbon atoms?
Interviewee - Patrick Walter
Exactly.
Interviewer - Chris Smith
When you bust open the ball with the laser.
Interviewee - Patrick Walter
In this case, you're not trying to bust open the C-60, you're freeing it from its source, it's kind of mixed with the individual carbon atoms as a vapour
Interviewer - Chris Smith
And occasionally incorporate that carbon atom.
Interviewee - Patrick Walter
Well that is what seems to be happening. So the answer to the mystery is that buckyballs eat individual carbon atoms.
Interviewer - Chris Smith
How did they know that? What were they doing to be able to detect that?
Interviewee - Patrick Walter
They used a very sensitive mass spectrometry technique to follow just how they're growing. So you can pick up the masses of these different buckyballs and what they got was a distribution of the buckyballs. So obviously the C-60 which is the source is there, but then there are slight bigger ones as well. So they're growing up to like C-76, C-84, so you get these much bigger ones and all it's got to grow is these individual carbon atoms.
Interviewer - Chris Smith
So, that shows that it can as you say eat individual carbon atoms. Do we know what the intermediates are then, does it in some way form some unstable intermediate, where you haven't got a nice beautifully regular buckyball for a while, until it grabs a few more carbon atoms and then assembles and reconfigures itself into one of those stable forms.
Interviewee - Patrick Walter
So, from a distribution, you can see that it focuses on the stable version. So if you think about it like a football, if you try to grow a football, you need to add another hexagon or another pentagon to make it grow into a stable shape. So in this case, adding just one atom at a time, you can have these intermediates, but they don't stick around long, so you keep adding more.
Interviewer - Chris Smith
And in a natural environment they would just grab some more carbon atoms and incorporate them into one of the stable forms or keep on incorporating them until they reached one of these stable shapes.
Interviewee - Patrick Walter
Exactly yeah, or if they couldn't find any more carbon, they might just kick it out and eject.
Interviewer - Chris Smith
So, chemically speaking because you started this by saying the question is well how these things grow and accretes carbon to form the structures we observe in nature. Do they have an idea as to the chemistry that's going on to enable them to grab these individual carbon atoms like this?
Interviewee - Patrick Walter
Well, this is what professor Kroto actually says that there still are missing piece of the puzzle. He says he's just not quite sure at the moment, how he can even begin to start investigating this.
Interviewer - Chris Smith
Gosh, there's a mystery. The same group Bibi have gone to also in the reverse direction and asked what's the smallest that we can make one of these buckeyballs, so what have they've been doing in that direction?
Interviewee - Bibiana Campos-Seijo
Yeah, Harry Kroto has been very busy lately. They've been trying to synthesize the smallest fullerene to date and actually formed spontaneously around a metal atom. They've used titanium, zirconium and uranium and they've been able to form a spherical C-28. The technique is called endohedral doping and they've been able to detect it.
Interviewer - Chris Smith
How does that work?
Interviewee - Bibiana Campos-Seijo
Scientists know that incorporating a metal into the fullerene makes it more stable and they wanted to synthesize the smallest fullerene possible because they knew in particular the C-28 was suspected to have really interesting properties. One of them would be ideally, if this were true, or if they were able to synthesize the compound, it would be room temperature superconductivity.
Interviewer - Chris Smith
So they predict that behaviour. They've got to make it though, so how do they actually make these very tiny metal doped structures?
Interviewee - Bibiana Campos-Seijo
It's a very similar technique to what Patrick was describing before, where they actually use a laser to vaporize the end of a carbon rod that has been lightly doped with the metal atoms. And basically, they use the same technique that Patrick was referring to before, the mass spectrometry to actually look at the vapour and see what's in there, and for the first time, they have been able to detect it. Now isolating it is going to be the trouble because..
Interviewer - Chris Smith
I did sense the 'but' coming along, so it's easy to make, in levels that a mass spec will pick up, but, I was going to ask you about stability and I guess you're going to say, it isn't very stable.
Interviewee - Bibiana Campos-Seijo
No, it is very highly reactive, thus the problem with these small fullerene. Kroto says that it should be structable, but probably in very small amounts, others doubt that it can be made into a significant amount. Once you take it out of vapour state, it's going to react with something else. So I guess that they will have to keep trying.
Interviewer - Chris Smith
Do they think that it's worth pursuing this or are they just going to say, or they have just said look it's not worth it for these reasons?
Interviewee - Bibiana Campos-Seijo
I think they'll persevere definitely. It is worth it because it's the smallest ever, So, I think they will definitely stick with it.
Interviewer - Chris Smith
Food for thought, thank you Bibi. Now from food for thought to food for fitness.
Interviewee - Mayur Ranchordas
My name is Mayur Ranchordas and I'm a senior lecturer and performance nutritional consultant at Sheffield Hallam University. The title performance nutritionist, the title first to helping athletes with their day-to-day nutrition in order for them to get the most out of their training that they do, so the three parts to it are fuelling the body for the training because the majority of the athletes train, you know, 30 to 40 hours a week,. And the second one would be recovery from exercise, so being able to recover from one so you can get the most out of the next. And the third one really is getting the most out of the adaptation so that you're getting the most out of your training sessions.
Interviewer - Chris Smith
So, just run us through then, what the key points of someone who is interested in optimizing nutrition in all those contexts? What sort of a role does it play?
Interviewee - Mayur Ranchordas
It can play a huge role, particularly when it comes to the adaptation from exercise. It all depends on the setting. So for example, if you are an endurance athlete, so you are a marathon runner or someone doing triathlons, then the majority of the training is spent doing endurance work, so their heart rates will be around 70 to 85 percent of their maximum for the majority of the training sessions and there will be, you know, 2 to 3 hours with this continuous exercise. In that respect, the goal of the training session is to maximize fuel use, you want to maximize the amount of fatty acid and lipids that the body is using, you can preserve carbohydrates in order to prolong the training session and enhance performance. There's some exciting research about training faster, so if you go out for say hour run, having breakfast before you go for your run could potentially impact some of the adaptation to that fuel equalization. So, having a strong cup of coffee and getting around sort of a 120 to 180 milligrams of caffeine would be fine in the typical strong espresso can actually enhance some of those fat adaptations, before you go for your training session.
Interviewer - Chris Smith
But to what extent is this just genetics. I mean, I'm different from you both biochemically and physiologically in many ways. So, is there just a simple rule of thumb, you should do this and this will apply to all, it doesn't sound intuitive really?
Interviewee - Mayur Ranchordas
It depends on your sports, so when we look at the physiology, you know, sprinters and marathon runners are born, they're not made. We can help them maximize the potential, so we can't make someone who isn't a sprinter run under 10 seconds, but if someone has the potential and has the genetic makeup, we can help them get the most of the physiology.
Interviewer - Chris Smith
But does the same rule, that would make one person run better tend to apply across the board or is there some sort of scientific way of saying, well we'll analyze you biochemically and we can see that you need to do the following things in order to get the genetic maximum out of you.
Interviewee - Mayur Ranchordas
It entirely depends. Some principles apply across the board. So, for example, the research that I was talking about earlier on training faster, enhancing you know, take the fuel utilization, that will be similar across the board in all endurance athletes, where the differences would lie would be everyone has individual biochemical makeup, so if you were then to analyze, something else that's popular in the media at the moment is vitamin D. We know that vitamin D is correlated with performance and muscle function and you know, if you've got very light skin or very dark skin or you spend majority of your time indoors, then you're at high risk at developing vitamin D either insufficiency or deficiency and that can impact performance and that could vary because that can be very genetically determined. So we need to measure that in order to correct it. So in that respect, you would have to give out individualized advice.
Interviewer - Chris Smith
How do you actually do your research there, would you work on an individual athlete, do some tests, make some changes and then almost like complete the audit cycle, you go back to the beginning and say, well how have we changed this person's performance and is it going in the right and anticipated direction?
Interviewee - Mayur Ranchordas
Yeah research in elite sports is really quite tricky because when you pick up a randomized control trial and you pick up a study that has been done on a number of recreational athletes, they respond very differently to a particularly nutrition intervention or some sort of training program an elite athlete would. So these are two different types of research you got your single case study design type research where you purely focus on enhancing performance and you're not interested in having a controlled group, you're not interested in having a placebo group, because you're purely interested on what can I do to enhance performance for this particular athlete and that will be the field research that we do. On the opposite end of the continuum in the laboratory setting some of these questions that arise from the field, so for example, you know this guy is improving once we give him this particular drink then we take that into the laboratory setting, then we set up a controlled, more of a mechanistic type example, so one of the recent things that we're doing is adding caffeine to a recovery drink because we found that there is evidence that adding caffeine to your recovery drink can enhance glycogen re-synthesis. In other words, if you're adding caffeine to your recovery drink more of that carbohydrate is being restored in the muscle compared to if the caffeine wasn't present and now we've seen that in the field, we actually need to measure that in the laboratory using muscle biopsies.
Interviewer - Chris Smith
So, if you prove that caffeine does have a performance enhancing effect does it then become judged to be a performance enhancing drug and potentially get banned or is it so ubiquitous that the Olympic authorities and others would never have a hope in having to pulling that one off.
Interviewee - Mayur Ranchordas
Yeah, the whole caffeine debate is very interesting. I personally feel that if caffeine was discovered today it would be placed in the banned list of substances, prohibited substances, because it is so ergogenic. Caffeine is an interesting one from the wider perspective because it used to be on the banned list at a certain level but it now has been removed and you know if we look through the caffeine literature, caffeine has been researched in sports and exercise , you know, well over 30 years now and the majority of the research seems to indicate that it has a performance enhancing effect regardless of it being team sport endurance or certain power.
Interviewer - Chris Smith
So, we are sticking with the caffeine, I will just take a sip of my coffee, when you work with professional sports people they're hiring you and they're saying okay I want to optimize my performance, so how do you approach that, how do you go up to Usain Bolt or whoever and say right we only make you run fast or what's your approach.
Interviewee - Mayur Ranchordas
Well you have to use what we call a multidisciplinary approach because in sports science, there are various aspects that can enhance the performance, the psychological aspects, the training and adaptation aspects, you have the nutrition aspects, you have the recovery and sleep and your point of sleep. So first and foremost, before you give out any advice, it's important to conduct what we call a need analysis. The need analysis really gives you an overall picture of what I like to call a helicopter view, what the athlete does. So how often do they train, what's his sessions, what's the volume, what's the intensity, their adequate recovery, what's being eaten before doing and after, what's the recovery after exercise, how much sleep does the athlete get and once you build that picture, then the majority of athletes start to see certain holes, where they're not doing things that they should be doing, where they might be taking a particular meal or a supplement, but at the wrong time or the wrong dosage, and that's really where our work comes in. We kind of fine tune all that, you know, make sure you're having breakfast at this time, you know, having your recovery in this particular ratio immediately after training so for example, carbohydrate protein in the ratio of 4:1 is ideal for recovery, but if you are just going to an extended training session in the gym, then you need to increase the protein to be about 30 grams and the quality of the protein can have a big difference on the adaptation to the muscle. So, these fine tuning things that make quite a considerable difference because if you think about an athlete training twice a day, six days a week, with one rest day, if you can get 1% out of every single training session. If you add those percent so, then you can have a dramatic impact on performance.
Interviewer - Chris Smith
Mayur Ranchordas from Sheffield Hallam University. Now how many scientists does it take to change a light bulb. Well, quite a few because the lighting industry is moving forward at a ferocious space, but on health grounds, what should I install at home, should I go for old fashioned incandescent bulbs, LED lamps or compact fluorescence. Elinor.
Interviewee - Elinor Richards
Well, it depends on whether you've got photosensitive skin or not, and UK researchers led by Leona Fenton and his colleagues at the University of Dundee have been looking at an ultraviolet emission that is given off by different types of light bulbs because of course the US legislated that now the traditional incandescent bulbs to be phased out by the end of this year.
Interviewer - Chris Smith
I know, we're going to have no traditional light bulbs to screw in, from the end of the year. The people that have made a noise about this, I suppose justifiably say, some people say that they have a skin issue, people with lupus for example say that their skin is very photosensitive and they have noticed that if they're exposed to say compact fluorescent lamps of certain types, then they do get skin reactions and they can be quite unpleasant for them. So, I suppose they're wanting to know well what could I use .
Interviewee - Elinor Richards
Yeah, so the researchers found out that's it's the LED lamps that give off the lowest ultraviolet levels. So they compared three main types of energy saving light bulb, compact fluorescent lamps as you just mentioned, energy efficient halogen lamps and the light emitting diodes or LEDs. An interesting thing that they did find that there was considerable variation amongst the compact fluorescent lamps. This isn't just between models and makes but within a single box of supposedly identical bulbs, there was a difference in UV emission.
Interviewer - Chris Smith
I mean, is it enough that we would want to worry, all these people with skin sensitivities would want to worry. Did they say this may have implications?
Interviewee - Elinor Richards
Possibly so for photosensitive skin, yeah, but they say it's impossible for them to recommend to the use of CFLs for photosensitive individuals, in lamps close to the skin for prolonged periods for example, on the desk, a desk lamp would be quite close.
Interviewer - Chris Smith
I wonder if the problem will be sort of solved by the fact that LED technology has moved on so fast and so far and these LED lamps are really now very good, very low power, I wonder if we're just going to leapfrog the CFL problem largely. Most people would just go straight to the LEDs.
Interviewee - Elinor Richards
Possibly yes.
Interviewer - Chris Smith
Let's take a sort of historical look now, Bibi what have you got for us going back to the 1930s is it, chemically speaking?
Interviewee - Bibiana Campos-Seijo
Yes, this is a really interesting piece of research actually that could contradict what you can see in many inorganic text books. This is a team of researchers from University of Bath and from UCL both in the UK and they describe this project as something that was bubbling along in the background. So, it wasn't their main idea of interest, but it's really interesting because basically they're saying that they were looking at, they were doing a systematic review of crystal types and they came across cuprous fluoride, so they looked in the text books and it says that well depending on the text book, it says that either it doesn't exist or it was synthesized in 1933 and has a zinc blende type structure. So, they felt well this is very interesting, we're going to do some sort of modelling of the compound and see what happens and actually they discovered that that structure is not quite right that it should have been quite unstable.
Interviewer - Chris Smith
So what is it, copper atom and fluoride atom, literally CuF, that's the chemical that they're looking at?
Interviewee - Bibiana Campos-Seijo
Yes, yes absolutely. So they did the modelling for that, they were interested in it because it was the missing semiconductor between zinc oxide and gallium nitride, they thought it would have really interesting properties, optical and conducting properties and wanted to see whether it could be prepared but looking at the report from 1933, they can see that it is inconsistent with what the modelling discovered and actually it shows us, well I've read that this structure has never been reproduced.
Interviewer - Chris Smith
So, do you think that people in 1930s really didn't make it after all then?
Interviewee - Bibiana Campos-Seijo
That's their conclusion. They say that they made an, well it is possible that they made an error and what they reported as cuprous fluoride it wasn't. Theoretically, it should have a completely different structure, it should be a cinnabar-type arrangement and it's not in any way what was predicted, but if somebody could produce it, they predict really interesting properties, in particular they're talking about doping cuprous fluoride with zinc oxide for example and they predict that this could be used as a visible light harvesting material for application in photochemistry.
Interviewer - Chris Smith
Because those little things that you put on key rings, that soak up light and glow in the dark, they're zinc sulphide and copper doped zinc sulphide things aren't they? So this would be an even better one of those, just saying.
Interviewee - Bibiana Campos-Seijo
Yes.
Interviewer - Chris Smith
So, why don't people make it is there a reason why we can't go out and get some CuF
Interviewee - Bibiana Campos-Seijo
Well, what they say in the paper literally is that a physical reason for the absence of reports for cuprous fluoride could be that the material is not thermodynamically stable. We are able to synthesize cuprous chloride, cuprous bromide, so all the other elements in the halogen group, we can make them react with copper, but for some reason, cuprous fluoride is one that we haven't been able to make.
Interviewer - Chris Smith
Fluorine is pretty horrible stuff, isn't it, they say, a brave person who would want to make that?
Interviewee - Bibiana Campos-Seijo
Yes absolutely.
Jingle
Interviewer - Chris Smith
You're listening to Chemistry World with me Chris Smith. Still to come PCR on paper, this is a card based test for HIV that's quick and very cheap. Plus why winners at the Olympics will be getting silver rather than gold medals this summer, oh dear! But first, when you're exerting yourself, you must have had that experience that you just can't give anymore. The brain's willing but the body can't deliver, but how does this happen. Our next guest has been working on how the brain controls the body's response to the demands we place on it and how this impacts on training.
Interviewee - Damien Bailey
My name is Damien Bailey, I'm professor of physiology and biochemistry at the University of Glamorgan, where I lead the neurovascular research laboratory. The main reason I was interested in the brain and interested in performance is because it all relates back to what I call the wonder molecule which is oxygen and it's always fascinated me, if you like from an evolutionary perspective, how we've become so incredibly reliant on a molecule which is potentially deadly when in excess. Certainly in terms of predicting athletic performance, we're coming to understand that those individuals that are capable of taking on board huge volumes of oxygen and be very efficient at using the oxygen in particular the way the brain handles oxygen, these are the best performance athletes in the world, these are the endurance athletes.
Interviewer - Chris Smith
So when you say, you're really interested in looking at the brain, as a model, is that because the brain is extremely good at regulating its own oxygen supply sometimes to the detriment it caused to the other tissues, it preserves its supply at all costs, and if you can understand how the brain does it in the phase of being extremely metabolically hungry, I think it's 20% of the entire oxygen consumption of a person, is just their brain, 2% of body mass, isn't it?.
Interviewee - Damien Bailey
That's right, yes. We think that exercise starts and ends in the brain, and again we think that oxygen and the amount of oxygen that the brain sees dictates how well we perform. At the top end of exercise, when individuals are about to become completely exhausted and fall off a bike for example, if they're pushing very very hard, an incremental exercise challenge. We've actually identified that there's a small dip in the amount of oxygen that the brain sees. I mean, we identified that this could be one of the limiting factors that dictates at least endurance exercise performance and the brain puts the break if you like on the rest of the body to protect it from the real extremes of exercise.
Interviewer - Chris Smith
Do you know where in the brain this happens and how it happens, is it the level of things like the hypothalamus at the bottom of the brain that controls bodily functions, is that the sensitive bit that then demotivates other senses in the brain stopping you working so hard.
Interviewee - Damien Bailey
We're limited if you like as to where in the brain we can look. For example, we use a technique known as the infrared spectroscopy, which allows us to measure cerebral oxygenation, so the concentration of oxygen in the brain and this focuses really on the cortex, the frontal cortex which is involved in information processing, if you like. We're interested in this area of course because of the rise in dementia, vascular dementia and neurocognitive decline, the mental agility as we get older slowly starts to decline and again we think oxygen is important. So we use this technique and focus on the frontal cortex, which we can detect changes during exercise. But some of the older structures within the brain certainly the brain stem and as you mention the hypothalamus hippocampus as well are very important areas and these areas are technically very challenging to image with a new real conviction using other technologies including magnetic resonance imaging of course.
Interviewer - Chris Smith
So, at the moment we don't really know how the brain is detecting this oxygen, we just know that it in some way it is and that's affectin
No comments yet