Self-cleaning solar panels and suicidal cancer cells

13 September 2010

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In this NewsFlash, we hear how scientists have created self cleaning solar panels using Mars Lander technology, how modified yeast could be used to make bioethanol more efficient, and how a new model of climate change suggests it may not be too late to reverse current trends. Plus what it is about particular pieces of music that can make you laugh or cry.

In this episode

00:28 - Self cleaning solar cells

A new high voltage way to clean your solar cells with less water and elbow grease involved.

Self cleaning solar cells

Many of the sunniest places on earth are also deserts, therefore the best place to put your solar cell is both very dusty and also very short of water to wash the dust off your panels, this can seriously reduce the efficiency of the system. Not only is this a problem on earth but the Mars rovers Spirit and Opportunity have been slowly loosing power and if it wasn't for the occasional martian mini whirlwind they would have conked out years ago.The Sun, as seen from the surface of Earth through a camera lens.

Malay Mazumder, a from Boston University has been working on this problem for lunar landers and may have come up with a neat water free solution which will work on earth too. The idea is to cover the solar cell with small transparent electrodes and then occasionally apply high voltage to these electrodes. The voltages are arranged to form waves moving across the panel, which charge up and then push dust particles away from and then across they panel.

They can remove 90% of the dust on a panel in about 60 seconds, and the energy use is very small despite the high voltages involved as the currents are tiny. So future Mars missions may be less dependent on lucky dust devils, and on earth solar power could be cheaper in deserts.

"The Blue Marble" is a famous photograph of the Earth taken on December 7, 1972, by the crew of the Apollo 17 spacecraft en route to the Moon at a distance of about 29,000 kilometres (18,000 mi). It shows Africa, Antarctica, and the Arabian Peninsula.

02:10 - A breath of fresh air in climate change debate

A new model of future greenhouse gas emissions suggests that it's not too late to reverse predicted climate change trends. In fact, the new study shows that the main greenhouse gas threats to Earth's future climate have yet to be built.

A breath of fresh air in climate change debate

A new model of future greenhouse gas emissions suggests that it's not too late to reverse predicted climate change trends. In fact, the new study shows that the main greenhouse gas threats to Earth's future climate have yet to be built.

Writing in Science, Carnegie Institution-based researcher Steven Davis and his colleagues mathematically "froze" the Earth in its present state of emissions and asked what would happen if all of the present grenhouse gas sources on the planet were allowed to continue emitting for their working lifetime, but without any new CO2-sources being added. In other words, is there already sufficient climate-change inertia with the greenhouse-gas-producing infrastructure we already have to mean that it's too late to make a difference? earthSurprisingly, the answer that emerged from the analysis was no; in fact, the study shows that it's what we build next that matters most to the future of the planet. Reassuringly, the team found that our present CO2-producing capacity, in its working lifetime of up to about 40 years, would see the CO2 level stabilise at about 430 parts per million (ppm), some way short of the 450ppm viewed by many scientists as the point of no return.

But we cannot afford to be complacent, caution the researchers. According to co-author Ken Caldeira, "because most of the threat from climate change will come from energy infrastructure we have yet to build, it is critically important that we build the right stuff now - that is, low carbon energy technologies."

05:16 - Asteroids in the outer Solar System

A paper published this week in the Astrophysical Journal presents the first direct observations of small asteroids in the outer solar system.

Asteroids in the outer Solar System

Gaspra AsteroidA paper published this week in the Astrophysical Journal presents the first direct observations of small asteroids in the outer solar system. This all began in June, when two amateur astronomers, on different continents, happened to be pointing their telescopes at Jupiter when they both simultaneously observed a two-second flash, apparently in Jupiter's atmosphere. Since then, astronomers have been working to explain what was seen.

It's likely that what was seen was a small meteor burning up in Jupiter's upper atmosphere, and research published this week produces a fairly precise estimate of the size of the object: probably around 10 metres across.

That's fascinating because it's the first time that such a small object has been directly observed at such a distance. We've always suspected that there must be a large number of small rocks in the solar system, but have never been able to see them at these distances or get much idea of how many there might be.Jupiter's Great Red Spot

This story was given another exciting twist in August when a second similar flash was observed by another pair of amateur astronomers. It seems highly likely that these events have always been occuring at a rate of a few per year, but that because they've generally been thought impossible to observe, they've gone unrecorded. If so, we may well expect to see a flurry of more similar discoveries in coming months.

If we do, that will be really exciting because we will begin to get an idea of exactly how many asteroid there are around Jupiter, and what the distribution of their sizes looks like. That will really help us to understand how material is distributed in the asteroid belt, and perhaps help us to understand where it came from.

08:29 - RNA-away cancer cells

A molecular magic bullet could hold the key to selectively deleting cancer cells from the body, a new study has shown.

RNA-away cancer cells

A molecular magic bullet could hold the key to selectively deleting cancer cells from the body, a new study has shown. Writing in PNAS, California Institute of Technology researcher Niles Pierce and his colleagues describe how they have developed a new breed of intelligent smart bombs that can penetrate cells but then only "detonate" if a cell is cancerous. A Prostate Cancer Cell

The technique makes use of short pieces of genetic material called small conditional RNAs. These molecules consist of two linked components, a "diagnostic" detection sequence, which probes the genes inside a cell for a predetermined tell-tale cancer sequence, and a therapeutic tail structure which, if activated by the diagnostic component locating its target cancer-specific gene sequence, triggers the cells to self-destruct. The technique works by fooling cancerous cells into thinking they been infected by a virus so that they activate an enzyme called PKR, which destroys the cell to prevent the imaginary virus from spreading. This occurs because when the diagnostic component of the conditional RNA identifies its genetic target, it triggers the "therapeutic" component to unwind itself and begin to join up with the therapeutic tails of other conditional RNA molecules producing double stranded RNA, which is usually only found in virally-infected cells. The team tested their anti-cancer bullets against four different cultured human cancer cell lines and were able to achieve between 20 and 100 fold reductions in the cancer cell populations.

If the approach can be successfully translated to patients it will provide a powerful way to selectively remove cancerous cells, including those that have spread (metastasised) around the body, whilst sparing patients the unpleasant side effects associated with current chemotherapy regimes.

11:58 - Variable fundamental constants

Some evidence has been found of the fine structure constant... varying.

Variable fundamental constants

Something which perplexes physicists is why the fundamental physical constants are what they are, why is the speed of the light about 300 000km/s, why is the charge on an electron 1.6 x 10-19C etc. and for that matter are they actually constant. This boils down to why does physics behave as it does, and is it the same everywhere?Artists concept of a quasar

The problem is that we can only do experiments to measure them precisely where we can get an experiment to - essentially just in our solar system. Otherwise we are limited to what we can observe. One fundamental constant we can observe very accurately is called the fine structure constant - this is a combination of the charge of an electron, the plank constant and the speed of light, and measures how electric field and quantum mechanics interact to create energy levels in an atom. And it can be measured by looking at the spectra of atoms, so it is very convenient for astronomers.

Close to the earth this seems to be constant, but John Webb and collegues from the university of New South Wales have been looking at some of the most distant sources we can see - quasars which are thought to be huge black holes accreting material billions of light years away. In 2003 they discovered that the fine structure constant appears to have increased about 1 part in 200 000 since the light left the quasars.

But this study was only done in the northern hemisphere, they have recently done a simlar study in the southern hemisphere using the Very Large Telescope in Chile, which has found something possibly even more interesting - the result was that to the south the fine structure constant was changing by about the same amount as you go back in time but it was decreasing rather than increasing.

They have found a fairly strong signal but only time and more experiments will tell if it continues to hold up. If it does it might explain why fundamental physics is so well suited to life, essentially because it varies throughout the universe and our form of life has only developed in the part of the universe where it can survive.

16:00 - Music, Emotion, and Pain Control

Also in the news this week, EPSRC funded researchers up in Glasgow have been investigating how we respond emotionally to music, and how this could lead to music being used in pain control. Sarah Castor-Perry caught up with the researchers involved to find out more ...

Music, Emotion, and Pain Control
Professor Raymond MacDonald, Dr Don Knox, Glasgow Caledonian University

Chris -  Also in the news this week, EPSRC funded researchers up in Glasgow have been investigating how we respond emotionally to music, and how this could lead to music being used in pain control. Sarah Castor-Perry caught up with the researchers involved to find out more ...

Professor Raymond Macdonald -  "We are all musical; every human being has a biological and social guarantee of musicianship. Everybody can learn to express themselves and communicate through music. Also, we are all musical in the sense that Louis Armstrong, jazz trumpeterwe all respond emotionally to music. When we listen to music, we are moved in quite profound and powerful ways."

Sarah -  So whether it's a soothing classical melody, or a raging angry rock song, we all have a hugely emotional relationship with music. That was Professor Raymond MacDonald at Glasgow Caledonian University, who is part of a project being funded by the Engineering and Physical Sciences Research Council to find out how music conveys emotion.

The project brings together Music Psychologists like Professor MacDonald, with expert audio engineers like Dr Don Knox, who has been using volunteers and specially developed computer software to analyse a huge range of pieces of contemporary music to determine the mood and emotion that they express.

Dr Don Knox -  " We try to classify and categorise music in terms of two axes - one of which is intensity and loudness and the other one is valence or stress - negative/positive stress. So they look at the general loudness and activity levels in the music and if they are above a certain point it might be classed as being exuberant and if it was negatively stressed it might be anxious or frantic. And we analyse and extract lots of audio and acoustical parameters from the music and map those pieces of music onto the axes."

Sarah -   But what makes us choose particular pieces of music in different situations?MaTrace Music Emotion Axes

Dr Don Knox -  "When we first say to people what we're doing, classifying music and emotion, some of the first comments you get are 'well, I put happy music on to do happy things and dance, and I'll put sad or relaxing music on to do this'. Really, it's much more complicated than that and the music psychologists are really opening our eyes to how people actually interact with music. That relationship and emotional connection with music and how people use it for stress relief and pain reduction is much more complicated than just happy music for happy things and sad music for sad things."

Sarah -  And classifying each piece of music in such a detailed way is allowing the music psychologists to figure out exactly what it is in the music that makes us choose it for a particular situation, and how it can affect not just our emotions, but our physical perception too.

Professor MacDonald explained to me how the project is building on previous studies, carried out with his colleague Laura Mitchell...

Professor MacDonald - "Earlier work purely looked at people's preference; so what we initially found out was that listening to your favourite music reduced your anxiety perceptions and your pain perceptions. We had a huge range of different types of music that was selected - things like Hotel California by the Eagles, Pachelbel's Cannon, In My Place by Coldplay. And we originally suggested that there were no common structural features between these pieces of music but Don's work along with Scott Beveridge has started to show how certain structural features of music are important in trying to predict their emotional effect on the listener."

Sarah -   So although there is still work to be done, the implications of the project are really exciting. On the one hand, knowing how people respond emotionally to particular structures found in music, like rhythm and timbre, could have clinical applications in music therapy and using music for pain control, and also, for all those music lovers out there addicted to their mp3 players, it could herald a new way of classifying the music in your library and new ways of searching for music to match your mood.

How music conveys emotion could benefit the treatment of depression and the management of physical pain.

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