Naked Science Q&A Show

29 July 2007
Presented by Chris Smith, Phil Rosenberg.

This week, clean coal technology - how to get the energy from coal without digging it up, why GM goats are helping to combat nerve gas attacks, and how scientists have found the 'itch' gene. We also find out why smog causes heart disease, how seafood in space can help to heal astronauts, and the weight of leaves on an average tree. Plus Drs Chris and Phil take a look at your science questions including 'tasting' music, the best way to dry your washing and can the moon affect the shapes of weather systems? In Kitchen Science Ben and Dave explain how to make a lens with a plastic bottle and some water.

In this episode

Scratching an itch

01:27 - Researchers scratch the surface of understanding itching

Researchers have uncovered a gene that transmits the itch sensation.

Researchers scratch the surface of understanding itching

Researchers have uncovered a gene that transmits the itch sensation.

The result means that drugs capable of providing the pharmacological equvalent of a "scratch" could soon be on the way, sparing pruritic patients the misery of chronic itch disorders like eczema.

Writing in this week's Nature, Yan-Gang Sun and Zhou-Feng Chen from Washington University in St Louis describe how they homed-in on a small population of sensory nerves that release a transmitter substance called GRP - gastrin-releasing peptide.

GRP locks onto a chemical docking station in the spinal cord called GRPR - the gastrin releasing peptide receptor. The researchers found that when they "knocked out" the gene coding for GRPR in mice, the animals became much less susceptible to itch-provoking stimuli than normal mice, but were otherwise normal.

The team also found that normal mice could be made itch-resistant by injecting into the spinal fluid a chemical that blocks GRPR, confirming its role in the itch-sensing pathway.

However, it's almost certain that there are some other itch pathways still waiting to be uncovered.

"The fact that the knockout mice still scratched a little suggests there are additional itch receptors," Chen points out.

But the good news is that GRP has been studied previously in connection with certain types of cancer, so there are already a number of drugs available that are known to block it.

"So now researchers can study the effect of these agents on the itch sensation and possibly move that research to clinical applications fairly soon," says Chen.

Astronauts to test the healing power of shrimps

American astronauts intend to test out a chemical found in the shells of shrimps that may help with healing in case of an accident on a long duration space mission.

Unfortunately our human bodies are not well adapted to coping with weightlessness. Our muscles waste away and so do our bones and it even effects astronauts immune systems. Bacteria, however seem to thrive under zero g. The Russian Mir space station was overrun by a bacterial colony that began making astronauts sick and similar biological activity is arising on the international space station. It's therefore vital that if an astronaut is injured we are capable of treating them. This may be particularly important in future long duration missions. NASA is aiming to put astronauts on Mars in the next 20-30 years and it will be an 18 month round trip with no ability to head home quickly in a medical emergency.

The chemical being tested is called chitin and is found in the shells of sea creatures and insects. It is a natural antibacterial agent that works by carrying an electric charge that attracts the surface of the bacteria, this kills them or stops them multiplying. The tests involve comparing mixtures of chitin, human white blood cells and bacteria fragments flown in zero g with identical mixtures on Earth.

Chitin is already being used by the US army, who impregnate bandages with the healing agent, and the work in space may allow the further development of treatment techniques back on Earth.

Diesel exhaust at the heart of arterial disease

Researchers have found that airbourne pollution can trigger damage to blood vessels. Ke Wei Gong and colleagues, from the University of California at Los Angeles, culture endothelial cells of the type that line blood vessels with particles from diesel exhaust and oxidised phospholipids of the kind associated with LDL or "bad" cholesterol. The cells were then analysed to study the patterns of genes that had been switched on or off in response to the exposure, compared with unexposed controls. The researchers found the diesel exhaust particles were affecting at least three genetic pathways linked to inflammatory processes in the linings of blood vessels. Next they exposed mice, which had been genetically programmed to develop the rodent equivalent of high cholesterol levels, to the diesel particles. They found the same pattern of altered gene activity in the animals as they had seen in the cell cultures. These results may explain the observed link between heart attacks and strokes and levels of atmospheric pollution, and also highlight a mechanism by which pollution might increase the risk of vascular diseases.

Super paper - tough as steel

Scientists at Northwest University in Illinois have created a super-paper, made of carbon that is tougher than steel, but still more flexible than ordinary carbon fibre. And even better than that, it's cheap!

Carbon has always been known as a fantastic chemical for producing strong materials, diamond, for example is made of a regular lattice of carbon atoms making it incredibly tough. Scientists have also created super strong carbon nanotubes, which are hollow fibres only a few atoms across made of carbon. The problem with carbon nanotubes is that they are expensive and complicated to make, which limits their usefulness.

The new carbon paper, by contrast is cheap and easy to produce, the team put graphene oxide particles which contain carbon into specially treated water and suck it through a filter. The water causes the grapheme to form a paper like structure on the surface of the filter, although exactly how this works isn't known.

This cheap strong product has potential applications in protective coating or electronic components, however it does have one problem - re-exposing the paper to water causes it to break down. Because water is so common, either in liquid form or just as vapour in the air this poses significant limitations. The race is now on the produce a waterproof version of the paper to increase its usefulness and who knows in a few years time you may be able to fly away on holiday in a paper plane.

China Cleaning up Beijing's Act for Olympics

The Chinese government have announced funding for a large-scale wind farm on the outskirts of Beijing in an effort to cut pollution in time for the 2008 Olympics. The 580 million Yuan (£50million) project, said to be the tenth largest in the world and Beijing's first, will involve the construction of 33 wind turbines with an annual generating capacity of 100 million kWh. Although slightly more costly (0.3 Yuan) per kWh generated, the wind installation will save 10 million tonnes of CO2 emissions per year, and Chinese officials have announced that 20 percent of Olympic venues are powered by wind-generated electricity. However, despite these measures, some are still sceptical that Beijing can clean up its air in time for next year's games. As recently as 2004 figures showed that the city only achieved clean targets on about 280 days of the year, and since then traffic has been rising by 15% per year. So don't hold your breath. Then again, perhaps do hold your breath...

Is it possible to have sinus problems without the pain around the nose and eyes?

Normally when you get a cold the reason that you get lots of mucus in the nose is that most colds are produced by viruses. Viruses can only reproduce if they infect one of our cells, when they do this the cell turns into a virus factory and pumps out thousands of new viruses which jump into the cells next door and you get a big area of inflamation which causes the local blood vessels to get leaky and the immune system moves in. You get the sensation of a blocked nose because of this swelling as well as the mucus. This mucus acts as a filter trapping dust bacteria etc. The mucus drains back into your mouth through a series of little tubes called sinuses. Most ways that this can go wrong are inherited, but some are not such as a pollip which is a localised growth of cells which can block one of these sinuses so the mucus can't escape and can build up and cause lots of pain.

Why does my nose go runny when I cry?

When you make tears which come from the lacrimal gland in the eye, they run through a tiny duct into the eye. They then run across the eye to the middle of the lower eyelid where there is a little hole called the puncton through which they drain into your nose. So when you cry you make an excess of tears so there is more to drain into your nose making your snot more liquid and your nose runs.

Would a candle flicker on a hot air balloon?

This would be the case if the wind was completely uniform and moving at a constant speed, because the balloon will get blown at the same speed as the wind so you wouldn't feel it. However if the wind changes speed in a small gust it will take a while for the balloon to catch up with the air and you would feel a gust, or if the wind isn't uniform over the whole balloon you will not be travelling at the same speed as the air near the basket so you will feel some wind. Also a balloon works because hot air is less dense than cold so rises, this means that air around the balloon will get heated up and rise, so the balloon itself will create weak air currents.

Why do towels absorb the water off your body after a bath?

Towels comprise lots of tiny fluffy fibres made out of a material that attracts water, such as cotton.

Because these tiny fibres have such a large surface area, you can get loads of water stuck to a towel instead of yourself.

As a rule, water tends to move from areas of high contentration to areas of lower concentration. A wet body has a relatively high concentration of water. When this is transferred to a towel, the large surface area of the towel fabric distributes the water molecules over a much greater surface area, so the relative concentration is lower. As such, the water is encouarged to move from the higher concentration on your skin to the lower concentration on the towel, and you get drier...

How much heavier do deciduous trees get when they grow leaves in the summer?

There are 177 000 leaves on a 48 foot Maple tree which has an area of about 1/6th of an acre - a lot of leaf area. A leaf weighs between 1 and 5g where 5g is for a big leaf like a horse chestnut so if you multiply 5g by 177 000 you get about 1 tonne, about the same as a small family car, not a huge weight as the wood of the tree will weigh a lot more than this. The big problem that leaves pose is their surface area because they trap wind the means that the wind exerts a big force on the tree which is much more difficult to deal with than their actual weight.

22:10 - Why has the summer been so wet?

In the UK, this summer has been the wettest on record so far, so what is going on with the weather?

Why has the summer been so wet?
with John Law from Weatherquest

Chris - What is contributing to the freaky weather conditions that we have seen so far this year?

John - The biggest thing is that we have seen lots of low pressures a lot further south than we would do normally.  They are driven mostly by the jet stream which is a really fast moving area of high altitude winds and is a lot further south this year than we would normally see.  It is the real driving force behind these low pressure areas which have been coming a lot further south and running across our country as opposed to being a lot further north which is I think where most of this rain has been coming from.

Chris - Why should a low pressure system trigger us to have rain in the first place?

John - In a low pressure system a lot of air converges into one place and as the air rises they produce clouds and with the clouds comes the rain, and this time of year with the temperatures higher than what you would find in the winter time there is a lot more moisture around and so a lot more energy to create lots of rain.

Chris -   Do we know why the jet stream is doing this unusual thing?  As I am not that old but this is by far the wettest summer I have seen.

John - Yes this is by far and away the wettest 3 month period, May, June, July we have seen since records began in the 1700s.  But there seems to be a lot of variation at the moment as last year we had a very dry summer.

Chris - What do you think is going to happen next month, is there going to be a late summer or are we going to go into winter having been acclimatised to it?

John - It is very hard to say what is going to happen next month, longer range forecasts are exceptionally hard to do, at the moment it looks like things are definitely set to improve in the next week or so it looks like things are going to get slightly more settled.

How do clouds stay up?

The droplets in clouds are very small things, only about 20microns or 0.02mm in size so it only takes a very small updraght to keep those droplets suspended in the atmosphere. Raindrops are above about 2mm so about 1,000,000 cloud droplets. When they are big enough to overcome the updraught they will fall down to earth as rain.

Does the moon exert an influence on cloud formation?

It is unlikely that it has an influence on individual clouds, as the tides are a tiny effect (they only alter the height of an ocean by less than 0.1%) but they may affect the whole atmosphere slightly by affecting the atmospheric pressure slightly. But the moon is unlikely to make much difference on an individual cloud.

Is the world running out of water?

As we have seen in southern Europe; Greece, Turkey etc. there has been a lot of hot dry weather. The water cycle in the world as a whole is very closed so water can't escape, so we are not going to run out of water. It is possible that the amount of rainfall will decrease, although most predictions say that it will increase, but the areas it is falling in and the times of year it will fall are both probably going to change causing upheavals.

Do the cells in a transplanted organ get replaced by your own?

No they definitely won't. Cystic fibrosis is a good example, when you are suffering from it you can't make the right type of ion channel - a pore in the surface of the cells - which means that the mucus gets really sticky and you can't get it out of your lungs easily. If it gets really bad you can transplant new lungs from a healthy donor and this work fine because they have a healthy copy of the cystic fibrosis gene in their stem cells which are making the lung wall cells, so the cells in the transplant work fine.

On a potato shaped object would gravity be the same all over?

Yes, these things are irregularly shaped, because they are not very large, their gravity is not enough to pull them into a sphere, so you are not always the same distance from the mass in the object so the gravity changes. Mars' moon Phobos is irregularly shaped and its gravity varies by about 50% depending on where you are standing which is important for the mission that is headed for this moon. With something this small the gravity is so weak that you want to land on the area with the most gravity or you will tend to float off or at least find it difficult to stay stable, so you may want to fire something like a harpoon into the ground to tie yourself down.

Could you have solar powered air conditioning?

A gas powered fridge is an immensely cunning device invented by Einstein that works by seperating ammonia from water by boiling the mixture then cooling the ammonia to liquify it which gives out lots of heat. This heat can then be absorbed again when the ammonia evaporates in a hydrogen atmosphere a bit like when your sweat evaporates, cooling down the fridge. The hydrogen is then seperated from the ammonia by dissolving it in water which makes an ammonia water mixture to go back to the start.If you could get the boiler hot enough there is no reason that you shouldn't use this principle to cool buildings, although it would probably involve concentrating the sun with lots of mirrors.Perhaps a better solution would be to use a stirling cycle engine, this is a form of engine that generates heat by moving heat from a hot place to a cold one, by allowing gas to expand at the hot end and then contract at the cold one. This drives a piston back and forth. So if you concentrated sunlight on the hot end and cooled the other end with air or water you cound generate power which could be used to drive an air conditioner.All of these processes move a lot of heat from somewhere hot to somewhere warm in order to pump a little heat from somewhere cold to somwhere warm, by far the most efficient solution is to not heat up the building in the first place by painting the roof white and insulating it, or to cool the building by natural convection.

39:30 - Chemistry World - Clean Coal and Anti-Nerve Gas Goats

Coal without the miners and goats fighting chemical weapons - we catch up with Mark Peplow, editor of Chemistry World Magazine

Chemistry World - Clean Coal and Anti-Nerve Gas Goats
with Mark Peplow, Royal Society of Chemistry

Mark - A group of scientists in china have been developing a way of getting energy from coal without having to dig it out of the ground. It uses the same technology as the Victorians did to make gas for their gas lamps. In this chinese pilot trial they have drilled into a coal seam first pumped air down ignited the coal and then pumped down steam. At the other end of the seam there is another pipe and through this pipe comes something called syn gas a mixture of carbon dioxide, carbon monoxide and hydrogen. This is half burned coal and can be turned into a variety of liquid fuels using a process called the Fischer Tropf process.

Chris - So you don't have to dig a vast hole in the ground, you can get energy out whenever you want it,

Mark - When they first tried this in the 1970s was to send miners down and essentially create a reaction vessel inside the coal seam. With this method they carefully control the heat and air and burrow their own pipe through the coal seam which is about half a metre wide which completely removes the need for anyone to go down there. With 5000 miners a year dieing in coal mining accidents this will clearly make a big difference?

Chris - How do you make sure the gas comes out in the right place?

Mark - This is about how some coal seams are layed down, they are surrounded by rocks which trap the gasses and only let it escape where you have drilled the hole.

Chris - So what is this I hear about goats and chemical weapons?

Mark -   A research company called Pharmathene based in Canada have genetically modified a herd of goats to produce a protective enzyme in their milk. This is an enzyme that can chew up organo-phosporous compounds such as Sarin which was used in the Tokyo underground attack in 1995. This enzyme is called Butyralcolinesterase and out of that herd of goats they can produce about 5g of this enzyme in every litre of milk. They have already stockpiled about 15kg of this enzyme.

Chris - So you extract this enzyme out of the milk and then inject it into someone who has been exposed to something nasty.

Mark - Yes we talked to a researcher called Patrick Massam in France at the military health service research centre, he told us that a dose of about 200mg of the enzyme can protect humans up to about 5 times the lethal does of something like VX or sarin.

Chris - Or even sheep dip? As organophosphates are implicated in farmers having problems with sheepdip and gulf war syndrome.

Mark - Yes that's right they kill the insects which kill the insect which cause problems in sheep, but they have also been implicated in something called sheep dipper's flu due to an accumulation of these organophosphates in the farmer's bodies when they have not been using proper protective equipment.

Synethesia and being blind?

There is someone who has perfect pitch because she related the pitch of notes to tastes in a similar way to you, so she could tell exactly which note she was listening to by what it tasted like. Some people can taste shapes for example. We think it is because of some crossed wiring in the brain so when you hear a note the nerves also stimulate the part of the brain that processes taste. Synesthesia quite often gets passed down in families so some of your relatives may be similarly affected. It is unlikely to be related to you being blind as a child.

Why does lightning rumble?

If a lighting strike is very close to you it sounds like a very sharp crack and then a bit of a rumble afterwards, the further away you get the longer the rumble can sound. So a lightning bolt will make a sharp short noise, but first of all the noise is produced along a line up to a couple of kilometers long (if you live in Arizona), so because sound travels at 330m/s it could take up to 6 seconds for the sound from the top to reach you so the sound will be spread out over several seconds. The sound is then further spread out as you move further away from the lightning because the sound can get to you directly or by bouncing off things. This means that the sound will take lots of different times to get to you and therefore be spread out over several seconds as a rumble.

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