Chemistry World Podcast - March 2008
00:10 -- Introduction
02.30-- Pernod still baffles chemists
04.30-- Robots wake up and smell the coffee
07.08-- Debate: Paul Burton from the Senlis Council think-tank and Thomas Pietschmann from the UN Office on Drugs and Crime discuss whether Afghanistan could redirect some of its illegal opium crop for licensed medicinal use
15.25-- Supercritical chemistry makes polymers that heal bone
17.40-- The energy-efficient house that BASF built
20.55 -- Interview: Peter Leadlay from the University of Cambridge explains how natural products are producing new weapons against antibiotic-resistant bacteria
26.55-- Reading genetic code directly from RNA
30.00-- Nanowires power up clothing
31.55-- What makes safety matches safe? And spring is in the air with this month's chemistry conundrum
(Promo)
Brought to you by the Royal Society of Chemistry, this is the Chemistry World Podcast.
(End Promo)
(00:10 -- Introduction)
Interviewer - Chris Smith
Hello welcome to this month's Chemistry World podcast with Mark Peplow, Victoria Gill, James Mitchell Crow and I'm Chris Smith. Coming up why the drink that turns white when you add water to it might be just the kind of tonic that the pharmaceutical sector is looking for.
Interviewee - Victoria Gill
What the team think is that if they can figure out the secret the sort of super stable Pastis emulsion, they'll be able to use it to form nanocapsules to encapsulate drugs for drug delivery for example, because this is obviously a really energy-efficient form of making oil droplets.
Interviewer - Chris Smith
More from Victoria on the science of ouzo on the way. And we'll also be meeting the robot with the taste for Arabica.
Interviewee - Mark Peplow
Researchers at Nestl? in Lausanne in Switzerland have basically developed a machine that can accurately tell you what a coffee tastes like.
Interviewer - Chris Smith
Sounds like the kind of caffeine fuelled-job I'd like and on the subject of addictive substances we'll also be looking at the problem of opium in Afghanistan; this of course turns the opium into heroin which then reaches the streets of Europe, but the chemical culprits are getting much harder to catch.
Interviewee - Paul Burton
Previously there were fairly large and fairly static labs usually around the tribal areas abutting Pakistan that would convert this opium into heroin. We're now seeing a high prevalence of mobile labs that enable conversion at a more local level within the country.
Interviewer - Chris Smith
More from Paul Burton of the Senlis Council on the way. They are proposing that we should buy the opium off the farmers so that it can be used legitimately. This we'll be hearing. The United Nations have every reason to think that's a bad idea. Plus in the future, if you think the music on your i-Pod sounds pense there might be a good reason.
Interviewee - James Mitchell Crow
Your i-Pod could one day be powered by your trousers, so it's literally when these crystals get bent or twisted, they generate a current, a very small current, but if you have enough of these, then you could potentially get enough power to run something like a mobile phone or an i-Pod.
Interviewer - Chris Smith
Sounds good. And also on the way is the solution to the last month's Chemical Conundrum
Interviewee - Mark Peplow
What makes safety matches safe?
Interviewer - Chris Smith
So if you were struck by the answer and you sent it in to us, then you could be a winner. We'll be giving you the correct explanation and the names of the winning entries later in the program.
(Promo)
The Chemistry World podcast is brought to you by the Royal Society of Chemistry. Look us up online at chemistryworld.org
(End Promo)
(02.30 -- Pernod still baffles chemists)
Interviewer - Chris Smith
Now some people love this stuff, but others can't stand it and I think I am probably among them, but the science of the famous aniseed drinks like Ouzo, Pernod, pastis and raki that turn white when you add water to them is fascinating, but it has also got chemists confused, Victoria!
Interviewee - Victoria Gill
Yeah! This seems to be baffling chemists. It's quite surprising that all the state-of-the-art chemistry that we have in Pernod seems to be defying theoretical chemistry. This comes out of a research institute in the Netherlands. The lead researcher is now based at MIT in the US and she has measured the tension between the bubbles that form in the emulsion in Pernod. Pernod being this oil-based aniseed drink that goes cloudy when you add water, which is known as the ouzo-pastis effect and the reason it forms is because the oil that gives Pernod its aniseed flavour is called trans-anethole oil and its insoluble in water, so when you add water to Pernod, the droplets of oil sort of form and suspend and form this milky solution because it doesn't dissolve. What they found looking at the energy between the water and these droplets is that they will stay stable in this solution even if you add more ethanol, which should technically make these droplets more soluble because they're soluble in alcohol, which is why Pernod or Ouzo is clear in the bottle.
Interviewer - Chris Smith
So, what are the things going on?
Interviewee - Victoria Gill
They don't know that's the really confusing thing. The emulsion remains stable over a very wide concentration of ethanol and water. And what the team think is that if they can figure out the secret, this sort of super stable Pastis emulsion, they'll be able to use it to form nanocapsules to encapsulate drugs, for drug delivery for example, because this is obviously a really energy-efficient form of making oil droplets. They form on their own without any additional energy. You'll know that in some emulsions you have to shake them up and add energy to cause this droplet formation, but in Pernod and water, they form and stay stable over a very wide concentration period.
(04.30 -- Robots wake up and smell the coffee)
Interviewer - Chris Smith
Well, from one exciting beverage to another, Mark. And that's coffee and a better way to taste it.
Interviewee - Mark Peplow
Yeah! That's right. One day machines may be able to wake up and smell the coffee; it's true. Researchers at Nestle in Lausanne in Switzerland have basically developed a machine that can accurately tell you what a coffee tastes like. Now for aficionados of coffee, they are often able to discern subtle differences in different types of blend, this complex aroma that comes from coffee is made up of more than a thousand different volatile compounds and if almost the taste is in the smell that you get in the air just above the coffee. Now these researchers have been able to develop a device that can basically sample the gas above a cup and relate the mass spectrometry results of that gas analysis to flavour profiles, which have been built up by human experts. So, what this group did was to ask experts to classify coffees in 10 different taste categories, such as bitter, woody or acid, things like that. The machine would then go away and with that knowledge compare it with the mass spectrometry results. Now mass spectrometer basically takes molecules, chops them up to do different pieces to create a sort of fingerprint jigsaw, if you like that tells you the profile of original compounds that were in the sample. Now the crucial thing about this machine is that it actually learns from experience. The more coffee it smells, the better it gets at correlating the data that it produces with what human experts have actually described about the aromas.
Interviewer - Chris Smith
But there's a lot more to coffee than just the way it smells, when you experience, the texture and the overall experience rather than just have taste.
Interviewee - Mark Peplow
That's true. But at some point and indeed these researchers have reached this point, the aroma research is an important part of process of experiencing coffee that they've now got this machine to the stage where, if they feed the machine with coffee first it can accurately predict what the human experts are going to say about the coffee, the machine can predict how the experts are going to rate this on these sorts of flavour categories like bitter or acid. Now ultimately, the researchers are trying to develop this so that they can basically enable rapid quality control on Nestl?'s coffees -- the whole process only takes about two minutes. I'm sure you've all seen these flavour experts that you see in tea or coffee manufacturers where they're slurping along a hundred different cups of tea in an afternoon, just to check that all the bags are coming out right. This is a way that it might actually be quicker and just as efficient to do it by machine.
Interviewer - Chris Smith
But not half as fun though, I'm sure, thank you Mark.
(07.08 -- Debate: Paul Burton from the Senlis Council think-tank and Thomas Pietschmann from the UN Office on Drugs and Crime discuss whether Afghanistan could redirect some of its illegal opium crop for licensed medicinal use)
Interviewer - Chris Smith
Now thankfully caffeine isn't very addictive, but morphine and heroin certainly are and a major street source of these drugs is the opium that's grown in Afghanistan, some of which they're hoping to fund the Taliban. The solution so far has been for the military to attempt to destroy the crops, but they're fighting a losing battle and now the European think tank, the Senlis Council is suggesting that farmers could be licensed to grow opium, which would then be bought back from them for pharmaceutical purposes, but the United Nations think that the plan is flawed. From the Senlis Council, here's Paul Burton.
Interviewee - Paul Burton
What we see within Afghanistan over the last 2-3 years, an explosion in the growths of poppy. With the Senlis Council contended at the current policies that are on the table are pretty much proven itself to be dysfunctional now. We have the option of eradication either by ground based teams, which is happening to a certain degree in different parts of the South in Helmand, in particular, at present.
Interviewer - Chris Smith
So, when you say they're eradicating things what's actually going on? How are people seeking to control these poppy growths?
Interviewee - Paul Burton
A US private military company called DynCorp has a very good contrast in their perspective to actually get in among some of the villages and destroy it. They do this on the ground either by ploughing trucks and SUVs through the field or informal crude measures by hacking away with sites at the poppy crops themselves.
Interviewer - Chris Smith
So they employ locals to do this or do they bring people in from outside to do it?
Interviewee - Paul Burton
DynCorp mentors the ANA or the ANP or some local body to do this.
Interviewer - Chris Smith
So where does all that material that gets produced if it isn't destroyed end up and how?
Interviewee - Paul Burton
At present, we know that there is a very direct correlation between the burgeoning insurgency and the cash that's generated for that insurgency by the opium crop. There's a very clear link now as indeed and the United Nations itself has demonstrated between the Taliban and Al Qaeda, whichever way you wanted to pick the insurgency in their capacity to launch increasingly judicious and high tempo asymmetric race against the west and the capacity of those groups to turn the opium into heroin onward to the European markets which are now awash with heroin in a way that we haven't seen for many years.
Interviewer - Chris Smith
Is that heroin produced on the ground so to speak in Afghanistan or has it moved out of the country as the raw material and then refined elsewhere?
Interviewee - Paul Burton
Yeah. I mean that's an interesting point previously there were fairly large and fairly static labs usually around the tribal areas abutting Pakistan that would convert this opium into heroin. We're now seeing a high prevalence of mobile labs that enable conversion at a more local level within the country.
Interviewer - Chris Smith
And so what would the Senlis Council, would like to see happen instead of external companies going in and driving trucks through people's fields?
Interviewee - Paul Burton
Well the Senlis Council has developed a Poppy for Medicine project model that involves licensing the controlled cultivation of poppy to produce essential poppy-based medicine such as morphine with unlicensed poppy cultivation remaining a criminal activity. Poppy licensing for the production of medicine is actually an alternative counter narcotic strategy that has been successfully implemented in many countries, Turkey and India in particular.
Interviewer - Chris Smith
Now, Dr. Thomas Pietschmann works for the United Nations office on Drugs and Crime. Thomas do you see this working?
Interviewee - Thomas Pietschmann
There was a doubling of production between 2005 and 2007, so we are talking now about 8200 tons of production in Afghanistan in the year 2007.
Interviewer - Chris Smith
That's a lot of opium isn't it?
Interviewee - Thomas Pietschmann
It's a lot of opium and there's the problem when you wanted to use this opium and put it into the licit circles, it just wouldn't work-you have far too much opium already. The licit production at the moment has gone down over the last few years, simply because there was too much opium on the market and we have in the year 2006, licit production of opium and opium equivalents transformed into morphine of a total of 335 tons.
Interviewer - Chris Smith
So what you are saying is that the world is already awash with these opium materials; we don't need anymore of them and therefore the strategy, which is being proposed by the Senlis Council isn't going to work because why should we need anymore?
Interviewee - Thomas Pietschmann
We have huge stocks we have 2 years of production in stocks at the moment. Countries have had to reduce dramatically the opium production, so we had a decline in the licit opium production of 65% between 2003 and 2007 in terms of hectors.
Interviewer - Chris Smith
So, Paul Burton from the Senlis Council -- The world is awash with morphine and we don't need anymore.
Interviewee - Paul Burton
I mean, that's just a standard argument that's put to it. I just like draw upon the stocks issue and yes of course there are significant stocks of raw poppy materials within several countries. The United States, France and Japan for example have stocks of around 200 tons between them; however, these stocks do not represent a global over supply. Stocks appear in the current poppy-based medicine supply system for two reasons. Firstly the International Narcotics Control Board, which oversees the amounts of morphine that each country has, their commodities constitute the raw materials over a range of essential medicines. Consumer countries often build up strategic methods to cope with future shortage. Secondly, producing countries build stocks to buy smooth price trend over time and compete effectively with other producing companies. So typically stocks of agricultural commodities are in levels, the wasting can sufficiently cover several years of consumption. In comparison stocks of raw poppy are relatively low because they manage within the current supply system -- the current supply system is deeply flawed. There is, as the World Health Organization said, "an unmet need for morphine" and if you break down the figures of all the morphine that's in existence in the world at the moment, over 90% of that is used by 6 countries, so there's a huge unmet need for morphine particularly in the developing world. We don't seek to convert all of Afghanistan's poppy into opium, but we do seek to convert sufficient quantities to start to address the unmet need in the developing world.
Interviewer - Chris Smith
Thomas that sounds like quite a compelling argument.
Interviewee - Thomas Pietschmann
Yeah. The basic argument is right that you have too little morphine being consumed in the developing countries and this comes from us-- this is our analysis and again we agree with our own analysis and which is also the analysis of Senlis Council. The problem here is not that there is not sufficient supply over here there is a problem on the demand side that you don't have systems in place, which allow morphine to get to people who are in need of it. It's not the question it's not available. It is there, it is waiting, but it's just not being used.
Interviewer - Chris Smith
So Paul, just returning to you finally, it sounds to me like there's a bit of a way to go before the strategy that you are trying to propose could possibly be rolled out.
Interviewee - Paul Burton
Sure and in the interim what we propose is the introduction of two pilot projects within villages in southern Afghanistan. This would allow us to test all facets of the Poppy for Medicine idea from the lowest level capacity of the farmer to turn it into the morphine tablets at the local level up the scale, right up to Kabul and onward to the international market and we have actually established a requirement for morphine form of a pilot project within the Brazilian context. So we have an onward market here for this brand of Afghan trade morphine if you like, that we are proposing. There is a critical mass building up within various countries to support pilot projects and we look to take this forward for the next planting season.
Interviewer - Chris Smith
Paul Burton from the Senlis Council and Thomas Pietschmann who works at the UNODC.
(Music)
(15.25 -- Supercritical chemistry makes polymers that heal bone)
Interviewer - Chris Smith
Now 'break a leg' as they say because there is every reason to be enthusiastic about getting better bone repairs in future, Victoria!
Interviewee - Victoria Gill
Yeah! This research comes out of the UK, one of the researchers is based at the University of Southampton and they've made a polymer that could be a replacement for bone grafts that could heal bone. Bone grafts are surgical procedures that take place when a bone has been so badly damaged that surgeons will take a little bit of bone and put it onto where you need your bone to be repaired so that it can undergo the healing process, but this polymer can replace that very invasive procedure. The tricky thing about it is you need sponge-like polymer that's full of holes and you need it to be seeded with bone marrow cells and with healing factors and growth factors to promote this healing process. Now these factors and these cells are extremely delicate physiological chemicals and cells, so the process to make these polymers, it needs to be very gentle, but to make a sponge like a very holey polymer often needs very aggressive solvents and high temperatures.
Interviewer - Chris Smith
Which would kill those living elements that you mentioned?
Interviewee - Victoria Gill
Yeah exactly! Which would damage those chemicals and damage the cells.
Interviewer - Chris Smith
So have they got around the problem?
Interviewee - Victoria Gill
They have used a solvent under pressure and the cells seem to tolerate this pressure, but their clever bit of chemistry is the solvent; its supercritical CO2; supercritical meaning that it's between being a liquid and a gas. Under pressure, the polymer mixed with the liquid CO2 forms and mixes together and the cells and chemicals that are needed to survive well and then as the pressure is released, it bubbles up and forms this holey-sponge-like polymer.
Interviewer - Chris Smith
And presumably the CO2 because the pressure is gone and evaporates.
Interviewee - Victoria Gill
Yes. Exactly! And this then produces a biodegradable and biocompatible polymer that has no toxic effects and they've tested it in animals and it heals well and works fine and biodegrades away; it all works extremely well.
Interviewer - Chris Smith
Yeah, they're going to unite say the two broken ends of the bone so that then you can get growth across using the graft as a sort of scaffolding.
Interviewee - Victoria Gill
Yeah, using the graft as scaffolding but also seeding the graft itself with your own bone marrow cells, it's sort of a form of tissue engineering as well.
Interviewer - Chris Smith
And given that it works so successfully in animals, have they given any indication as to when they see trials happening in humans?
Interviewee - Victoria Gill
That's a big jump and it's a big clinical trial to be able to undertake, as patients would have to actually undergo surgery, but yeah that's the next step to take it clinical.
(17.40 -- The energy-efficient house that BASF built)
Interviewer - Chris Smith
We're talking about building things, not necessarily out of bone, but out of environmentally friendly things, James amazing that BASF have done this with this house.
Interviewee - James Mitchell Crow
That's exactly right Chris. Yes at last the BASF have finished up in Nottingham. I went and visited them and they've used all sorts of clever bits of chemistry to make this house as energy efficient as they can.
Interviewer - Chris Smith
I mean, you wouldn't say looking at the picture that it's the most exciting looking house, certainly looks futuristic, but it also looks like a Lego house, forgive me, but what's so special about it?
Interviewee - James Mitchell Crow
Funny you should say that it's a Lego house, because the ground floor walls of the house actually are made of polystyrene blocks that slot together exactly like Lego bricks, but around the other side of the house, the south-facing side is basically the entire wall is made of glass.
Interviewer - Chris Smith
So a massive sun trap in other words.
Interviewee - James Mitchell Crow
Exactly yes! The whole idea is to get as much energy as possible directly from the sun through passive heating.
Interviewer - Chris Smith
And then keep it in by using the fact that you got this polystyrene, which is a very poor conductor of heat, so once the heat is in it stays in.
Interviewee - James Mitchell Crow
That's right. Yes. So there are various bits of technology that they've used to keep the heat in. So as well as being polystyrene these blocks are grey rather than the white of your usual polystyrene coffee cup, because they've got little flexive graphite in, now what this does is reflects back in heat that is radiating out of the room.
Interviewer - Chris Smith
Ingenious! What else have they done?
Interviewee - James Mitchell Crow
The roof and upper floor of the house are made from another kind of polymer -- polyurethane panels. These are big panels sandwiched between two pieces of wood, so there is very little air transfer and then any extra bit of heat that needs to be used to top-up the house comes from a biomass boiler. So what this boiler uses is locally sourced chips of waste from oil seed rape plants that sort of tops out the heat. The house also features a ground heat exchanger. So, it uses the fact that the ground is always at constant 10 degrees, summer or winter. So, in the summer the air is taken through pipes in the ground and by the time it comes into the house it's cooled down, but in the winter, it's actually warmed up by the ground.
Interviewer - Chris Smith
They seemed to have thought of everything. How does this compare with say, a standard house, if you do the energy calculations? How much better is this?
Interviewee - James Mitchell Crow
It's actually a whole lot better. A typical house uses about 200 kilo an hour per meter square of energy whereas this house only uses 15; that's only about 7% of the energy used within the house.
Interviewer - Chris Smith
Wow! And in CO2 terms what would that equate to, in terms of emissions you don't make because your house is so much more efficient.
Interviewee - James Mitchell Crow
It would produce 7% of the CO2 because it only uses 7% of the energy. This is a step towards the UK's government stated goal by 2016 all houses will be zero net energy emitting houses.
Interviewer - Chris Smith
And taking a look at it, as you have, would you live in it?
Interviewee - James Mitchell Crow
I would actually. I think its well; it's a different looking house. People will actually be living in the house in order to sort of test in real conditions, just how much energy the house does use. Initially its going to be students living in the house in order to test in realistic conditions exactly how much energy the house does use, although I think the professors (UNCLEAR 20:42), want to live in it themselves.
Interviewer - Chris Smith
Thank you, James. Although I'm not sure of the logic behind testing is supposedly environmentally friendly house on students, mind you noise pollution is probably not part of the equation.
(20.55 -- Interview: Peter Leadlay from the University of Cambridge explains how natural products are producing new weapons against antibiotic-resistant bacteria)
Interviewer - Chris Smith
Now something that regularly makes headlines is the issue of antibiotic resistance and the rise of super bucks. So I met up with Cambridge University biochemist, Peter Leadlay, to find out how he is trying to tackle the problem.
Interviewee - Peter Leadlay
For a number of years now, we've been asking the question where do antibiotics come from, I mean, the natural products and we know they are produced largely by bacteria in the cell, but we've been using them for 40 years without much clue and so we've been sequencing genes and trying to understand how these things are made.
Interviewer - Chris Smith
In other words the organisms that naturally make what we call antibiotics, or antimicrobials, why then make them in the first place?
Interviewee - Peter Leadlay
It is, if you like, nature's chemistry set and we believe that they are produced to defend the organism against competition in the cell, which is a very difficult habitat and particularly for certain bacteria with a complicated life cycle. They actually create food for themselves by part of the colony sacrificing themselves for the greater good and it's just at that point that they produce the antibiotics.
Interviewer - Chris Smith
So the idea here is that these would then fend off other things coming in to scrape up the debris and scavenge, so the bacteria then don't get any competition.
Interviewee - Peter Leadlay
Yeah. That's right and so they would need to make agents that would defend them against both bacteria and fungi.
Interviewer - Chris Smith
Does this mean then that pretty much every antimicrobial we are using, we are developing probably already has a correlate in nature.
Interviewee - Peter Leadlay
Ever since penicillin, the natural world has been plundered for new antimicrobials. It's only in the last 30 years or so that people have tried to make synthetic compounds that would do the same job and the richest vein for discovery of new drugs is natural products.
Interviewer - Chris Smith
How do we go about getting a new kind of antimicrobial from nature's chemistry set?
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