Chemistry World Podcast - December 2009
00.11 - Introduction
01.52 - Nanoscience brings artworks back to life
04.30 - Monitoring asthma with mobile phones
07.00 - Mike Barlow on spectroscopy opening windows on the universe
14.03 - Acid solution for nanotube fibres
16.09 - New evidence for toxic effects of inhaled nanotubes
19.02 - Sigurd Hofmann on the discovery of element 112
25.28 - DNA stretching mystery solved
29.10 - New catalyst converts CO2 to useful molecules
32.00 - The chemical conundrum - what analytical technique is being used by scientists to prove the existence of water on the moon?
(Promo)
Brought to you by the Royal Society of Chemistry, this is the Chemistry World Podcast.
(End Promo)
(00.11 - Introduction)
Interviewer - Meera Senthilingam
Hello and welcome to the December edition of the Chemistry World Podcast with Bibiana Campos-Seijo, Phillip Broadwith and Anna Lewcock. I am Meera Senthilingam from the thenakedscientists dot com. Coming up in this month's show, how mobile phones could soon benefit our health.
Interviewee - Anna Lewcock
We have the latest, slightly unusual app for your mobile phone. They've basically implanted a sensor into a mobile phone that will measure levels of nitric oxide in your breath.
Interviewer - Meera Senthilingam
Anna Lewcock will be explaining how breathing into your phone could be the new way of monitoring asthma. Also on the way, why we have spectroscopy to thank for our understanding of our universe.
Interviewee - Mike Barlow
Almost all the information we gather about the universe is based on spectroscopy. Up until 1930, it was believed that the composition of stars was very similar to that of the Earth.
Interviewer - Meera Senthilingam
And Mike Barlow will be explaining how his team are using spectroscopy to understand the origins of life on Earth. Plus we will meet one of the founders of one of the newest elements to be added to the periodic table.
Interviewee - Sigurd Hofmann
We bombarded a lead target that has 82 protons with a zinc beam containing 30 protons and we were able to detect a single atom of an element with 112 protons, Element-112.
Interviewer - Meera Senthilingam
Sigurd Hofmann will be explaining how his team went about discovering this element and what this could mean for the future of elemental findings. That is all coming up on this month's Chemistry World Podcast.
(Promo)
The Chemistry World Podcast is brought to you by the Royal Society of Chemistry. Look us up online at chemistryworld dot org.
(End Promo)
(01.52 -- Nanoscience brings artworks back to life)
Interviewer - Meera Senthilingam
First this month, we discover how scientists have been trying to restore works of art, how are they doing that Bibi?
Interviewee - Bibiana Campos-Seijo
During the 1960s and 70s, restorers used to treat artwork with a polymer coating to protect it from damage.It used to act as a sealant and also some form of protection against light,but over the years, these polymers have oxidised and become yellow or darkened,and they need to be removed. Also they talk about some interaction with metals using ancient paints as well, so that needs to be resolved.
Interviewer - Meera Senthilingam
So, how have they gone about removing these?
Interviewee - Bibiana Campos-Seijo
Yes, a team led by Piero Baglioni at the University of Florence in Italy have designed a transparent gel that can be applied over the surface of the painting and it is made out of a small amount of a volatile solvent called para-xylene dissolved in water and then thickened into a gel with hydroxyethylcellulose.
Interviewer - Meera Senthilingam
And how does this gel actually work to remove the polymers and the damage caused to these arts?
Interviewee - Bibiana Campos-Seijo
The gel has a microstructure of tiny droplets of oil-coated water that are trapped in the cellulose chains, so they will dissolve the organic polymers that have been applied over the surface of the painting, but the advantages are that because this gels are so viscous they will not penetrate at the surface of the painting which is one of the problems that they had traditionally where the solvents were actually getting into the photo's matrix where there was the painting.
Interviewer - Meera Senthilingam
So essentially this is going to sit on top of the painting and drew around the polymers and draw out the impurities then?
Interviewee - Bibiana Campos-Seijo
Yes, and it can be monitored visually actually because this is transparent, so they can apply it and see how it cleans the surface, so it is allegedly very easy to use.
Interviewer - Meera Senthilingam
That sounds great, so what they have managed to use this on so far?
Interviewee - Bibiana Campos-Seijo
So far they have restored some wall paintings from the 15th century at the Santa Maria della Scala Sacristy in Siena, Italy and also they have applied it to a gilded frame from the 18th century, so yeah, obviously it works.
Interviewer - Meera Senthilingam
But is it applicable to all forms of art then?
Interviewee - Bibiana Campos-Seijo
Not yet, the next challenge for them is to assign a system that can be used to clean oil paintings, the difficulty with these is that these paintings are made with layer upon layer of organic-based paint - and there is the danger that important fixing molecules could be dissolved, so that is the next point that they are going to try and fix.
Interviewer - Meera Senthilingam
Okay, thank you Bibi.
(04.30 - Monitoring asthma with mobile phones)
Interviewer - Meera Senthilingam
And now moving away from pieces of art on to technology now and that is the mobile phone. Now I know mobile phones can be used for a lot Anna, but now they are also being used in medical monitoring of asthma.
Interviewee - Anna Lewcock
Yes that is it. We have the latest, slightly unusual app for your mobile phone that has been developed by a company called Applied Nanodetectors and they have basically implanted a sensor into a mobile phone that will measure levels of nitric oxide in your breath.
Interviewer - Meera Senthilingam
So how does this work to monitor the levels of nitric oxide and how is this inserted into your phone?
Interviewee - Anna Lewcock
Basically, there is a small hole in the top right hand corner of the phone and within that there is a carbon nanotube and silicon-based sensor. We do not know very much more about how it works because the company is reluctant to release anymore details, but basically when you breathe into the hole, the sensor works out the proportion of nitric acid in your breath and five seconds later, you could read out on your phone that tells you the amount of nitric acid in your breath in parts per billion and you get a traffic light warning icon indicating if the concentration is normal, so you get a green light or not so good, so you get a red light.
Interviewer - Meera Senthilingam
So all people really need to do is to monitor this then basically is to breathe onto their phone.
Interviewee -Anna Lewcock
Yeah that is it. So the idea is that hopefully it will help patients keep a daily record of how they are doing and how their asthma is progressing and also the information will hopefully be forwarded straight onto their doctor or their healthcare provider, so they can keep a record and if you end up getting a red traffic light warning, they will be able to drop you a line and you will be able to arrange an appointment straight away.
Interviewer - Meera Senthilingam
Now why is monitoring the levels of nitric oxide valuable for monitoring asthma in an individual?
Interviewee -Anna Lewcock
Okay. So inflammation in your airways causes elevated nitric oxide levels in your breath and nitric oxide has been used as a biomarker for asthma since about 1995 and using nitric oxide levels as a monitoring test for asthma has been approved by the US Food and Drug Administration for several years now.
Interviewer - Meera Senthilingam
And how often more people have to do this then?
Interviewee -Anna Lewcock
Ideally the developers would like it to become sort of a disease-monitoring habit, so you just have a breath and breathe in everyday, so you can keep track of how your asthma is coming along.
Interviewer - Meera Senthilingam
And I guess lastly, is it possible to monitor other diseases using this technology potentially then as well?
Interviewee -Anna Lewcock
Well, there are around 200 chemicals that get exhaled in every breath, so if there is a biomarker in one of those chemicals and if we can find a suitable sensor then there is no reason why other ones can be incorporated within the phone.
Interviewer - Meera Senthilingam
So as well as cameras and e-mails, our phones could also now help us have daily health checks without doctors. Thanks Anna.
(07.00 - Mike Barlow on spectroscopy opening windows on the universe)
Interviewer - Meera Senthilingam
Now the field of astrophysics still has many unanswered questions about the origins of our universe, but what we do know so far about our stars and our planets is largely down to the technique of spectroscopy. So to find out more about what spectroscopy is and just how it works, I went along to University College London to meet Mike Barlow.
Interviewee - Mike Barlow
Well, spectroscopy is a very powerful fundamental technique as widely used in astrophysics to diagnose particularly the chemical composition of stars and nebulae and galaxies. It basically splits light up into its component wavelengths, disperses as we say. We then have a detector, which collects the light, dispersed over its different wavelength ranges. When you inspect the resulting spectrum, you see absorption or emission lines which will allow you to identify them with particular ions or atoms or molecules and knowing that their present length immediately gives you information about the composition of an object. In particularly, rich spectra, you get many emission or absorption lines and the ratios of these different lines can allow you to infer the densities, the temperatures and the role of elemental abundances of the different elements.
Interviewer - Meera Senthilingam
And what forms of light and what wave lengths are used in spectroscopy?
Interviewee - Mike Barlow
Well, astronomers observe the entire electromagnetic spectrum all the way from gamma rays to radio, there are satellites that have to go into space for certain wavelength regions because the Earth's atmosphere does not transmit the radiation of those wavelengths, that includes x-rays, ultraviolet, and a lot of the infrared spectrum. For instance, x-rays, you see atomic transitions that originate from the inner electrons of tightly bound atoms like iron or oxygen and so forth, the K-and L-shell as they are called. They can again allow you to infer information about the regions that are emitting or absorbing these elements. You move into the ultraviolet and you see electronic transitions that are from less tightly bound elements but from very abundant elements like carbon, nitrogen and oxygen. Moving into the optical, you see less tightly bound elements, more like sodium, calcium, potassium and once you are in the infrared, you begin to see molecular transitions and it can be vibrational in near-infrared or if you go out to longer wavelengths which we call the mid-infrared or the far-infrared, we begin to see many rotational transition to molecules such as water or carbon monoxide and so on.
Interviewer - Meera Senthilingam
So what do you and your group look at, at the moment or what have you looked at in the past and which type of spectroscopy have you used?
Interviewee - Mike Barlow
Well, I have in the past used optical, ultraviolet and infrared spectroscopy to understand the composition of nebulae in our galaxy and in another nearby galaxies. The reason for this is we would like to know the abundances of elements like carbon, nitrogen, oxygen, very important elements, the most abundant elements after hydrogen and helium. And if we want to understand the role of abundances of these elements in the solar system and on Earth, we have got to work out how the stars made them by nuclear processes. Stars then later ejected these nebulae, maybe a supernovae or through a mass loss process of lower mass stars and they enrich the galaxy in heavy elements over time. So by observing nebulae in our own galaxy and other galaxies, we can diagnose their chemical composition today. We can compare that with galaxies which are less evolved and therefore have lower elemental abundances and we can look at the patterns in those galaxies and by comparing the patterns of elemental abundances we can get information about what types of objects like supernovae are responsible for enriching those elements.
Interviewer - Meera Senthilingam
And so what have you found so far about which elements are present here?
Interviewee -Mike Barlow
We would like to understand the origin of carbon, nitrogen and oxygen and one of the puzzles at the moment is we know that oxygen is dominantly produced by supernovae, massive stars that exploded at the end of their lives. Carbon is more controversial. For long time we thought that carbon came from low mass stars like the Sun, but more recently there has been claims that massive stars too might be able to make a lot of carbon. So we are going, I must say, back to basics to understand whether it is stars or the Sun that produced most of the carbon or whether it is massive stars, or outgoing supernovae that did it.
Interviewer - Meera Senthilingam
And so knowing where the main source of carbon came from then, what can this then be applied to help us understand?
Interviewee -Mike Barlow
Well, carbon is clearly an important element for life on Earth. There is a lot of evidence that complex molecules and complex organic dust particles existed in the earlier stages of solar system and helped to get the whole process of life going on a planet such as the Earth.
Interviewer - Meera Senthilingam
How important do you think the field of spectroscopy, say, has it been to the understanding of our planets, our stars, our universe?
Interviewee - Mike Barlow
Well, it is a bedrock tool for astrophysics. Almost all the information we gather about the universe is based on spectroscopy, in combination with imaging, but with imaging alone we would know very little about the universe. We need these key bits of information, if I could give an example of what spectroscopy did. Up until 1930, it was believed that the composition of stars was very similar to that of the Earth, dominated by heavy elements like iron, silicon and so forth and it was not until the study of a series of spectra of stars of different temperatures by an astrophysicist called Cecilia Payne-Gaposchkin, she realized that in fact hydrogen and helium are found more abundant in stars and it was that realization that was needed in order to work out what the energy source for stars. As soon as she knew that, hydrogen was the dominant element then it occurred to physicists through the 30s that fusion of hydrogen atoms into helium could provide the energy source that was needed to power stars. Prior to that nobody knew what the energy source was.
Interviewer - Meera Senthilingam
That was Mike Barlow, professor of astrophysics at University College, London explaining how the technique of spectroscopy has greatly increased our understanding of our universe.
(14.03 - Acid solution for nanotube fibres)
Interviewer - Meera Senthilingam
You are listening to Chemistry World with me Meera Senthilingam. And still to come we reveal just how far our DNA can be stretched and we reveal how chemists go about finding a new element, but before that we investigate why scientists have been dissolving carbon nanotubes, Phil.
Interviewee - Phillip Broadwith
Yes, that is right Meera. Matteo Pasquali and a group from Rice University in Texas have found that carbon nanotubes actually do dissolve in something and that something is chlorosulfonic acid, which is a superacid, which is even more acidic than concentrated sulphuric acid.
Interviewer - Meera Senthilingam
And now why is it useful to dissolve nanotubes?
Interviewee - Phillip Broadwith
Well, a lot of the excitement about carbon nanotubes is about their, sort of, engineering properties, they are very strong, but they also have, they also conduct electricity, but bringing those exciting properties into the real world means being able to process nanotubes on a large scale into things like fibres or films and that is just not possible unless you can get them properly into solution.
Interviewer - Meera Senthilingam
So how does this chlorosulfonic acid actually work to dissolve the nanotubes then?
Interviewee -Phillip Broadwith
Okay. Well, previous ways of making nanotube solutions type things have been to actually physically modify the surface of the nanotube, whereas chlorosulfonic acid is actually a strong enough acid to directly proteinate the surface of the carbon nanotubes. This makes them positively charged and they then repel each other which gets over the problem of nanotubes tending to clump together in solution, which is what stops them from dissolving.
Interviewer - Meera Senthilingam
And so what are the potential applications of this now?
Interviewee - Phillip Broadwith
Because they can make solutions in liquid crystals, there are lots of established ways of processing those solutions in liquid crystal phases into fibres or films or whatever, so they can use established technology such as that that is used for Kevlar, to process these into fibres. Then you can start making composite materials, but you can make composite materials that are not only very strong but also conduct electricity, so one thing that the authors have mentioned is that the aerospace industry, if you think of an aeroplane fuselage, it needs to conduct electricity to survive lightening strikes which is why aluminium is used quite often and but if you want to replace that with a lighter, composite material, to save weight and fuel, you still need something that conducts electricity which you might be able to do with nanotubes.
Interviewer - Meera Senthilingam
Well, thank you Phil.
(16.09 - New evidence for toxic effects of inhaled nanotubes)
Interviewer - Meera Senthilingam
And now staying on the topic of nanotubes, but moving over to the disadvantages Anna, and scientists are worried about the effects of nanotubes on our health.
Interviewee - Anna Lewcock
Yes, absolutely! If carbon nanotubes are going to be processed and used on a wider scale, it means that a lot more people could be exposed to carbon nanotubes at higher concentrations and this research has come from James Bonner of North Carolina State University in the US and his team suggest that inhaled carbon nanotubes could cause some damage when they reach the lungs.
Interviewer - Meera Senthilingam
So what damage is it thought that they may have on our lungs?
Interviewee - Anna Lewcock
Well, given that carbon nanotubes have a similar structure to asbestos, because they are long and fibrous, it is concerned that they have the same effect as inhaled asbestos dust, which was reaching a certain area of the lungs where they cause damage and lung disease.
Interviewer - Meera Senthilingam
Now what area does it reach and why does it getting into this area have a negative effect?
Interviewee - Anna Lewcock
Well, most particles are cleared out of the lungs quite effectively by the body's defences, but it is found that these long fibrous particles reach the pleura, the two-layered membrane separating the lung from the chest wall and they settle there, they are not cleared out as well as other particles.
Interviewer - Meera Senthilingam
And what is the kind of disadvantage of then sitting and settling there?
Interviewee - Anna Lewcock
Well, people are concerned that they have the same effect as asbestos, which was to cause mesothelioma, which is a slow growing lung cancer and cause other sort of scarring and tissue damage in that area of the lungs.
Interviewer - Meera Senthilingam
What is the kind of evidence backing this and so how did the scientists look into this?
Interviewee - Anna Lewcock
Well, this is the first research that has been carried out on carbon nanotubes where it has been in more of a real life setting. They got the mice to inhale the carbon nanotubes rather than injecting it to some part of the body as they had done in previous research. So the researchers exposed the mice to carbon nanotubes, which they inhaled for about 6 hours and then they collected lung tissues after 1 day, 2 weeks, 6 weeks and 14 weeks after the inhalation exposure.
Interviewer - Meera Senthilingam
But I guess 14 weeks is not that long in terms of a scientific study. So is this still early stages or is it actually something we should worry about already?
Interviewee - Anna Lewcock
It is still very early stages. This is something that the researchers are very keen to point out. For example, there is no sign of the slow-growing cancer because 14 weeks that is simply not long enough for such thing to develop, but also there are other concerns that there is some evidence of scarring after 2 weeks, 6 weeks and 14 weeks, but that could be down to the catalyst, the nickel catalyst that was used to form the carbon nanotubes. The researchers are very keen to stress that although they found evidence that the carbon nanotubes reaches the same place in the lungs as the asbestos particles, they have not made any conclusions as to the kind of damage that they do or do not cause there.
Interviewer - Meera Senthilingam
So it is something to maybe worry about but also something that needs just a lot more work to finalize the actual details of this.
Interviewee - Anna Lewcock
Absolutely! A lot more research is needed as to what damage is or isn't caused and how it would or would not happen.
Interviewer - Meera Senthilingam
So whilst we should keep an eye on carbon nanotubes, seeing if their popularity in industry is increasing, it is not quite something to worry about just yet. Thanks Anna.
(19.02 - Sigurd Hofmann on the discovery of element 112)
Interviewer - Meera Senthilingam
Now, have you ever wondered just how chemists go about finding a new element, especially an element that is so unstable that it only lasts for a few seconds. Well, this months for our sister podcast, Chemistry in its Element, where we bring you the stories and chemistry behind the elements in our period table, I met Sigurd Hofmann, who led the team that discovered element 112 and apparently this discovery all began with a question.
Interviewee - Sigurd Hofmann
Our question is simple, but difficult to answer. What we want to know is how many elements are there or where is the end of the periodic table? The elements beyond uranium (those with an atomic number greater than 92) are not found in nature because they have short half-lives, meaning they exist for only very short periods of time before they decay. So, if we want to know how many of these elements, called the transuranium elements exist we have to try and make them in the laboratory. In 1996 we set about producing element 112, inside a particle accelerator. We bombarded a lead target - that has 82 protons - with a zinc beam containing 30 protons for one week, and were able to detect a single atom of an element with 112 protons - element 112. As is standard for these types of experiments, we used isotopes of zinc and lead with high numbers of neutrons. Our zinc nuclei had 40 neutrons and our lead nuclei had 126 neutrons, so that the nucleus of our new element had 112 protons and 166 neutrons, me
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