Chemistry World Podcast -May 2011
1:16 - Battery turns entropy into electricity
3:35 - Antibacterial clays kill with iron
5:54 - Yi-Fang Chu from Kraft Foods explains the potential health benefits and pitfalls drinking coffee
13:06 - Origin of life experiments revisited
15:53 - Cleaning up nuclear storage ponds
19:16 - Katherine Holt from University College London escapes from her addiction to caffeine as part of Chemistry World's Chemistry in its element sister podcast series
25:20 - Nanoparticles help reveal hidden fingerprints
28:05 - Cool roof coating inspired by the poplar leaf
31:40 - Trivia - how long and at what temperature should you cook a boiled egg to get the perfect runny yolk?
(Promo)
Brought to you by the Royal Society of Chemistry, this is the Chemistry World Podcast.
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Interviewer - Chris Smith
Hello welcome to the May 2011 edition of the Chemistry World podcast. With me this month are Laura Howes, Mike Brown and Andrew Turley and they're here to discuss how to turn salty seawater into electricity, how clay can slay E. coli and the world's number 1 chemical vise.
Interviewee - Katherine Holt
I sustained myself to the withdrawal symptoms, the headaches, the tiredness, the irritability, the aching muscles and joints waiting for the promised land where I would sleep more deeply, be more focussed, concentrate better and no longer have to plan my holidays or indeed my life around the availability of coffee.
Interviewer - Chris Smith
And the good 80% of the world's population are probably similarly hooked including me, that's the chemistry and addictive potential of caffeine and coffee and it's on its way. So put the kettle on and enjoy this very well brewed edition of the Chemistry World podcast, with me Chris Smith.
(Promo)
The Chemistry World Podcast is brought to you by the Royal Society of Chemistry. Look us up online at chemistryworld dot org.
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(1:16 - Battery turns entropy into electricity)
Interviewer - Chris Smith
They say that you shouldn't mix water and electricity but that could be about to change, thanks to a new way of extracting energy from salinity, Laura.
Interviewee - Laura Howes
Well obviously when water from the river runs into the sea there's actually quite a lot of entropy from the mixing and the difference in the entropy between the two water sources.
Interviewer - Chris Smith
Because the sea is very concentrated and fresh is less.
Interviewee - Laura Howes
Exactly, so people have been trying to use this to extract electricity.
Interviewer - Chris Smith
I have come across this before but they have been doing this with membranes where you put salt water on one side of the membrane, fresh water on the other, use the movement of the ions to drive the current.
Interviewee - Laura Howes
Yeah, that's right but this sounds different and the way this is different is that is it has no membrane at all, instead they are using a sort of flow of water between two electrodes, the electrode lattices actually absorb the ions and so that the sodium, say, and the chlorine and absorb them into the lattice and then you put freshwater in between the two and the ions come out.
Interviewer - Chris Smith
So you have these electrodes. They dangle into a solution, let's say you put salt water in first, these electrodes in some way take out some of the ions walk away somewhere, you then what change the water?.
Interviewee - Laura Howes
Yeah, so then got the freshwater come in, so what the scientists are thinking at Stanford University, Yi Cui and his team are thinking is that you could actually use the flow of water and the river water so you could have it sacked up the river mouth getting the salt water ions and then using the flow of river water to actually flush in and flush out the salt water and do a charge-recharge process in that way.
Interviewer - Chris Smith
That sounds fantastic but is it viable?
Interviewee - Laura Howes
Well I mean it's working in the lab, obviously getting it to the river mouth is obviously a bit of a stretch. I mean, they hypothetically think that if they used all of the river mouths that would sort of suitably put a plant on every river mouth you could make about 13% of the current energy consumption of the world.
Interviewer - Chris Smith
Gosh! That's a lot but what sort of infrastructure do you need to build, because is this going to mean that you render a river mouth completely useless for shipping or anything else, is this a huge great building?
Interviewee - Laura Howes
It wouldn't be a huge great building, obviously you would have to divert some of the river water into your plant but you shouldn't have to plunk a great big building in the middle of your rivers, you should still be able to use it for other purposes.
(3:35 - Antibacterial clays kill with iron)
Interviewer - Chris Smith
To watch that one, that sounds interesting, I haven't come across that before. And Andrew from one wet thing, rivers to clay and it has antibacterial properties.
Interviewee - Andrew Turley
Yes apparently, historically clay has been used to combat various conditions to heal the skin and very recently in Ivory Coast people have been using it for something called Buruli ulcer, it's a flesh eating disease.
Interviewer - Chris Smith
Not nice.
Interviewee - Andrew Turley
Specifically they've been putting on something called French green clays and this group led by Linda Williams of Arizona State University in the US has been investigating what makes these clays work or if indeed they do work although it does seem that they do.
Interviewer - Chris Smith
Is this a sort of a self remedy than that is now being used in a pharmacological way, people found it does appear to work and now they're trying to work it why?
Interviewee - Andrew Turley
That exactly, the clays vary in their ability to combat bacterial infections. Some of the batches are better than others. So what this group did was look at a wide range. They pulled out the one that had the best properties which had come from the Cascade Mountains in Oregon from an open pit mine there and what they found is the iron in or what they're speculating is the iron that combats the bacteria.
Interviewer - Chris Smith
Do they know how?
Interviewee - Andrew Turley
They ran some tests on E. coli and they found that the iron accumulated in the E. coli in the presence of clays, the antibacterial clays had eight times as much iron inside the cells and they think that the iron is oxidizing inside the cells and forming hydroxyl radicals which are destroying the cells from the inside.
Interviewer - Chris Smith
So can we expect to see Ivory Coast green clays finding their way on to the shelves of chemists in the near future? I mean are they saying this is actually practical?
Interviewee - Andrew Turley
I think this is probably a long way off for this particular remedy but obviously there's a huge amount of interest in new antibacterial agents, new antibiotics and this is one of many different ways that researchers are trying to fill that need.
Interviewer - Chris Smith
I think I will stick to a helping of Dettol in the meantime all the same. Thanks Andrew. Now to an extraordinary scientific field previously was believed to be impossible. Yes researchers have actually found something that not only tastes great but it's apparently also good for you.
(5:54 - Yi-Fang Chu from Kraft Foods explains the potential health benefits and pitfalls drinking coffee)
Interviewee - Yi-Fang Chu
My name is Yi-Fang Chu and I work for Kraft Foods, who are the second largest coffee companies in the world and I am a scientists with Kraft. My area has been coffee research.
Interviewer - Chris Smith
Hi, Fang thank you very much or joining us, now I've got in front of me my cup of coffee, this is finest Arabica I'm told by the company, not yours, that made this blend for me, what questions do you ask about coffee?.
Interviewee - Yi-Fang Chu
First can we swap that to our blend?
Interviewer - Chris Smith
Well it depends maybe if you show me some nice free samples, I'll consider it. Anyway what are the questions you're looking at?
Interviewee - Yi-Fang Chu
A couple of years ago when we're starting to look at the scientific literature on coffee we start to notice that knowing more evidence of its original evidence suggested that coffee may have some health benefits, so that's a surprise to us too because not many people think about coffee as a guilty pleasure that you can doubt yourself that you have to suffer the consequences.
Interviewer - Chris Smith
Are there a mixture of both health benefits and health dis-benefits, in other words, are you just reporting to us the positives because this is in the company's interest to do that or are there clear net benefits of being a coffee consumer, I hope there are being as I am one.
Interviewee - Yi-Fang Chu
We want to portray this area pretty fairly so the prior research have indicated some health disadvantages of coffee, but scientists now look back into the literature and start to find that all the findings are probably a little bit of misunderstanding because at that time people did not adjust cigarette smoking and alcohol consumption along with coffee, so they started to realize that if you put coffee separately, it actually has a pretty surprising finding that its correlated to health benefits, mainly for type 2 diabetics and some cognitive benefits in Parkinson's disease.
Interviewer - Chris Smith
So you're saying that many of the prior studies had other confounding variables in them, people pouring themselves a cup of coffee but then lighting a cigarette and some of the health dis-benefits that was spotted could well have been allied to those other behaviours. What sorts of positive health benefits are associated with coffee and to what extent is that the caffeine and to what extent is that other things in the coffee.
Interviewee - Yi-Fang Chu
I will take type 2 diabetes for example. I think this is so far the most convincing evidence showing that coffee is correlated to reduce risk of type 2 diabetes. The recent meta analysis that summarize the data show pretty clear correlation between one cup of additional coffee consumption has 7% reduced risk of type 2 diabetes. On the other hand caffeine itself - it's actually not good for diabetes, it can actually increase your glucose intolerance, so it's not that good for you in the short term but in the long term if you keep drinking coffee for 10-15 years the study has been concluded that it's pretty good for you in terms of managing your type 2 diabetic risk.
Interviewer - Chris Smith
What mechanism do you think is going on to help to reduce the risk of type 2 diabetes in people who do have that additional cup of coffee?
Interviewee - Yi-Fang Chu
We are looking that three main hypothesis, the first one is antioxidant, where the coffee can help manage the oxidative stress that may be caused by stress in life maybe caused by getting old, maybe caused by you have some food that's not good and that increase in the oxidative stress level in the body and then whether coffee, antioxidant can help combat when the level back to balance a little bit; that's the first one - antioxidant activity. The second one we're looking at is anti-inflammation activity to see whether coffee can help manage that because in long term it has been shown to be very bad for our health. So we want to see if coffee can help manage this inflammatory biomarkers that in return does help us manage our health, therefore we want to see if coffee molecules can help to manage our blood glucose; so that can eventually help us manage type 2 diabetes.
Interviewer - Chris Smith
Do you actually know what chemicals in the coffee might be the key players in achieving some of these effects?
Interviewee - Yi-Fang Chu
The main compound that's being hypothesized is chlorogenic acids. They are a group of compounds that has different forms. They're probably around 10 to 15% dry weight in coffee and also we are finding more and more evidence to think that maybe during the roasting process, some of the compound will form and also chlorogenic acid will become dense, into a chlorogenic acid lactone. So, we are still trying to figure out exactly how the compound that's in coffee that can help manage the health.
Interviewer - Chris Smith
What about the caffeine though, I mean, that's the thing that I'm hooked on. If I don't drink coffee regularly, I do get side effects. I had a test on myself last week. I went cold turkey for a day. By about 10 o'clock in the morning, I was feeling quite shaky, by midday I had the world's worst headache, and by 1 o'clock I was almost asleep in my desk and I caved in by 2 o'clock. What do you say about that aspect because caffeine is very motivating on the one hand but then cynic say that the reason it's so motivating is that as soon as we have some, it releases us from our withdrawal effects and so we can concentrate better?
Interviewee - Yi-Fang Chu
Yeah, caffeine can reduce withdrawal syndrome. You can have physiological effects that have different effect to different people. The European Food Safety Regulation Agency does have this report about caffeine and coffee that the only population we have to worry about - pregnant woman, lactating, also very young child - that's the population we really have to be careful about. Where while it has many benefits, but it still has this alcohol so they will be pretty similar to, to keep that in mind that coffee is this thing that even though we have many beneficial components that may contribute to your health, but there is pretty sure an acute effect to your performance day to day. So you just have to be aware of that.
Interviewer - Chris Smith
As the old saying goes, do stupid things more quickly with caffeine. That was Yi-Fang Chu from Kraft. And in case, you're now developing chemical cravings for more on the science of coffee, don't despair, Katherine Holt is waiting in the wings to talk about her own experiences of kicking the habit.
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Interviewer - Chris Smith
You're listening to Chemistry World, with me Chris Smith. Still to come, how scientists have revolutionized fingerprinting process with a bit of help from nanoparticles and why poplar trees might hold the key to more efficient air con. First though, Laura to new insights into where the building blocks of life came from.
(13:06 - Origin of life experiments revisited)
Interviewee - Laura Howes
That's right. In 2007, a chemist called Stanley Miller died, sadly obviously, but his former student Jeffrey Bada inherited the contents of Miller's lab and office and started playing around with some of the samples, he was finding there. We've spoken before because he's been looking at vials from Stanley Miller's earlier experiments.
Interviewer - Chris Smith
Maybe we should just remind people. I mean, these experiments were seminal, well the idea of what the early earth was like, putting mixtures of gases like nitrogen and hydrogen , methane into flasks and some water, boiling it out and sparking it. You get all these interesting chemicals.
Interviewee - Laura Howes
Yeah, exactly. Stanley Miller was very involved in origin of life experiments, tried to find out possible ways that life could've come into being on early primordial, sort of parts of the earth, looking at whether they probably happened in the sea or whether it was by volcanoes, and he was trying out lots of different sort of potential conditions to see whether he could spark and make amino acids, the building blocks of life.
Interviewer - Chris Smith
So, what is different in this experiment compared with the experiments that Jeff Bada did a few years ago reanalysing Stanley Miller's stuff?
Interviewee - Laura Howes
So, the really kind of fun thing for me personally about this experiment, although it does actually give us new scientific knowledge is that Miller had actually done these experiments in 1958 and he'd done them in a similar way to his sort of seminal important works, but he'd actually introduced some hydrogen sulfide into the mix, and he'd done all the work, he's got his samples, but he doesn't seem he's actually ever analyzed them or written up about them.
Interviewer - Chris Smith
Intriguing. So not only is it a variant on the stuff we already knew about, but it also had never been further developed either by him or anyone else.
Interviewee - Laura Howes
Exactly. So he'd actually just sort of left them. It seems like he's just forgotten about them, although the writing was in his lab, but samples were there, all neatly arranged, neatly labelled, exactly as he should do for scientific experiments and it's actually quite a nice example of why you should always keep your samples labelled nicely because you never know someone can prove that you've been a genius and you never knew.
Interviewer - Chris Smith
So they've come along and put these samples from many years ago through modern day analytical techniques. What did they find?
Interviewee - Laura Howes
So they found many amino acids. One of the most important things that they found is that with the addition of the hydrogen sulphide, they've got the sulphur-containing amino acids and the products with the sulphur-containing amino acids. Miller has actually made the sulphur-containing amino acids cysteine and methionine, but he didn't manage to do that until 1970 odd and you know, he did it in a different way. So this is a sort of tandem method that you could also get these amino acids containing sulphur.
(15:53 - Cleaning up nuclear storage ponds)
Interviewer - Chris Smith
Amazing how his results continue to be generated even years after his death. Thank you very much. Now Mike this is a relevant story because of what's been happening over in Japan, but it isn't directly about Japan, it's a more generic thing about the nuclear industry.
Interviewee - Mike Brown
Yeah, that's right Chris. We've heard a lot in the news about the nuclear disasters and what can happen when a natural disaster occurs. We've got danger to our nuclear reactors. This is talking about spent nuclear rods, spent uranium rods that's stored in nuclear power stations, and what we can do with them afterwards. How we can make them safe, maybe recycle the plutonium in them to be used again and then dispose of them properly.
Interviewer - Chris Smith
Because after they finish being reacted in the core, they're taken out and put into a pond, just a swimming pool, basically to cool down as in cooling the thermal as well as the radioactivity sense aren't they?
Interviewee - Mike Brown
Yeah that's right. So what will happen is the fuel rods are called Magnox rods, and they basically got a uranium core which is what's used in the nuclear reactor and they're encapsulated with magnesium and aluminium alloy. So what happens is after the uranium has been used, it goes into the ponds as you said and the uranium decays into other radioactive isotopes and one of these is plutonium. What they suggest is that because you've got loads of these rods decaying at the same time, you actually have tons of plutonium that you could actually recycle and use. So what they're looking at is trying to recycle it, trying to get this out and use it.
Interviewer - Chris Smith
Sure what's the technique?
Interviewee - Mike Brown
They've made their own nuclear storage pond.
Interviewer - Chris Smith
Simulate them without having to actually play around with plutonium presumably.
Interviewee - Mike Brown
Well, they have actually put some plutonium in it, so that the storage pond that they've made consist of plutonium, also some sludge stimulant which includes magnesium hydroxide, sodium carbonate, polyelectrolytes and some silica and the magnesium hydroxide has been seen to sequester the plutonium forming a colloid and what they've found is that using neutral pH or acidic pH, they can actually dissolve the plutonium into a solution and then they can actually filter it out.
Interviewer - Chris Smith
I get it. So you have a way of sequestering it under one pH condition, you then filter it off as a solid or extract it as a solid and then you remobilise it by just switching the pH and you got your plutonium out.
Interviewee - Mike Brown
Yeah, yeah.
Interviewer - Chris Smith
And what sort of scale could this be used on? Is this scalable, could you actually apply this with this work, industrially?
Interviewee - Mike Brown
It is just an experiment at the moment, but it does give indications as to, you know, scaling up in the future. With nuclear power becoming much more important at the moment with carbon emission and things like that, we need cleaner fuels, this kind of research is becoming more and more important especially with all the spent nuclear rods that we've got.
Interviewer - Chris Smith
Are there any risks though Mike? Because obviously one worry is yes you might get back X amount of the plutonium but is there any leakage from the system as in any that you don't manage to get and therefore that could be lost or contaminate things?
Interviewee - Mike Brown
Yeah, I think at the moment, that's another question that is still out there. The team are going to be doing further experiments to see whether they can actually quantify this and see whether this is actually happening, but it's definitely a step in the right direction.
(19:16 - Katherine Holt from University College London escapes from her addiction to caffeine as part of Chemistry World's Chemistry in its element sister podcast series)
Interviewer - Chris Smith
Mike Brown. Thank you Mike. If you're a Chemistry World regular, then you might know that in 2008, we launched a sister program called Chemistry in its Element and that's set out to tell the story in weekly instalments of the elements that make up the periodic table. We've played some of the episodes for you here, but after the periodic table was completed, we then began to take a look at what happens when those elements join together to make the compounds that count. And with the story of 1, 3, 7-trimethylxanthine better known as caffeine, here's Katherine Holt.
Interviewee - Katherine Holt
During the 17th and 18th centuries, some of the most creative ideas in art, literature and science emerged in the coffee houses of Europe. The finest minds of the time gathered daily to imbibe coffee and discuss the ideas of the day. Runners were employed to spread news between coffee shops. So they became an inevitable hub of the community and essential to the spread of information and inspiration. Whether such social progress was a consequence of the meeting of minds or the stimulating effect of caffeine can't really be quantified. Perhaps it was a bit of both. I used to think of myself as a modern day version of the coffee house intellectual. A good strong cup of coffee was required to blow away the cobwebs and sharpen the mind and the day could not possibly be started without one. But a few months ago, I realized I was no longer drinking coffee to feel good. I was drinking it to avoid feeling bad. I realized I was addicted to the stuff; addicted to such an extent that I took a cafeti?re and a bag of my favourite coffee backpacking with me because heaven forbid I should be without it even for one day. Enough was enough; I decided to give up this vice entirely. I sustained myself through the withdrawal symptoms, the headaches, the tiredness, the irritability, the aching muscles and joints, waiting for the promised land where I would sleep more deeply, be more focused, concentrate better and no longer have to plan my holidays or indeed my life around the availability of coffee. I read about the evils of coffee on the internet, how it supposedly causes dehydration, indigestion and most distressingly of all cellulite. Most of these claims are not however backed up by science. Caffeine is a mild diuretic, but studies have shown that it actually has about the same diuretic effect as plain old water. So drinking coffee is unlikely to cause dehydration. Any link between caffeine intake and indigestion also vanishes once other factors in particular degree of body fat are taken into account. Caffeine has some structural similarities to another molecule called adenosine. Adenosine accumulates in the brain as a product of various metabolic processes. After prolonged neuronal activity, for example, after thinking or working for a long time, higher concentrations of adenosine build-up in the brain. Adenosine is detected by specific receptors and high levels induce a feeling of tiredness or sleepiness. The build-up of adenosine is therefore a trigger that we should rest or sleep to allow our brain to recover. So where does caffeine come in? Well, it's structural similarity to adenosine means it can bind to adenosine receptors, but without triggering them. This prevents the receptors from detecting adenosine and thus the signal for tiredness is not given. Surely, I thought, giving up caffeine could only be a good thing. It must be better for my brain to regulate itself without intervention. Caffeine is however a safe and socially acceptable drug. Almost every nation on earth has their favourite version of a caffeinated drink from green tea in China to Yerba Mate in Argentina. The caffeine-containing Kola bean has for centuries been used by the people of West Africa to increase energy. The Mayans in South America produced the earliest forms of hot chocolate from cocoa beans, which was so esteemed they were used as a form of currency. Coffee was first drunk in Ethiopia, where the coffee plants grows wild. Legend has it that a goat herd had noticed that his goats became sleepless and excitable after nibbling at the berries on the coffee bush. After trying it himself, he experienced the same effects. Whatever the truth of this tale, coffee found its way to North Africa through Persia and eventually to Europe via Turkey, but why is caffeine found in so many different plants? Presumably its not there to keep the plant awake. Actually it's a natural pesticide; they can paralyze and kill insects that feed upon the plant. The soil around coffee seedlings is also been found to be rich in caffeine. It is believed this may inhibit the germination of other coffee seeds in the vicinity, giving the seedling a better chance of survival. So how is my caffeine-free existence? To be honest, I have mixed feelings. I enjoy the freedom of being released from my addiction, but I'm definitely aware that something subtle has changed in my brain chemistry. Scientific studies have shown that caffeine increases our capacity for physical work and may improve some aspects of mental performance - for example memory and ability to focus. Sometimes, I think that the caffeine free me is lacking a little edge. I can't say I've noticed much difference in the cellulite either.
(25:20 - Nanoparticles help reveal hidden fingerprints)
Interviewer - Chris Smith
Well, maybe that nonetheless explains my trim athletic and cellulite free physique or may be not. That was UCLs Katherine Holt and if you'd like to meet more of the compounds that count, they're all online at chemistryworld dot org forward slash compounds. Now Andrew - fingerprinting.
Interviewee - Andrew Turley
Right, so fingerprinting is very old technique, but it's actually still very important, very relevant for crime scene investigators, but you have an inherent problem in that. They're d
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