the-BA : Science News Digest

Flood and trees (Copyright: iStockPhotos.com)

In the news this week: tumour paint from scorpions, how a megaflood shaped Britain, the world’s first household eco-computer and is listening to music really as good as sex?

Cancer surgeons have found an unlikely ally in the ongoing fight to improve survival rates, in the form of the scorpion. A team based in Seattle has found a chemical derived from scorpion venom, chlorotoxin, when bound to the florescent marker, Cy55, makes for a very effective infra red “tumour paint” which could help surgeons to distinguish between healthy and cancerous cells.

At present, surgeons still rely on the colour, texture and blood supply of the tissue to identify the malignant areas but this rudimentary method can be unreliable. Indeed, in brain surgery, 80 per cent of cancers return as not all the tumour cells have been removed by surgeons worried about damaging the precious neurons.

The use of the paint means that cancers can be detected earlier because even clusters of just 2000 cells will glow whereas the traditional MRI scanner can only pick up more advanced cancers of one million cells or more. The paint could also be used for non-invasive screening for many types of cancer. If it passes toxicology trials, then the technique could be use in 18 months time.

Dr James Olsen, the head of the Seattle based team told the Independent: ‘My greatest hope is that tumour paint will fundamentally improve cancer therapy. By allowing us to see cancer that would be undetectable by other means, we can give our patients better outcomes’.

The transition from knuckle walking on all fours to walking upright marked an important stage in the evolution of modern man. The reason why this happened has long divided scientists; is it to do with keeping cool in the tropical sun, enabling our early ancestors to wade through water or saving energy in a food scarce environment? A study published in Science this week, has added credence to the energy expenditure theory with some hard data.

A comparison of chimps and humans walking on a treadmill with various gaits has concluded that bipedalism is about four times more efficient than moving on all fours. Researchers from the University of Tuscon, Arizona, observed five adult chimps walking on a treadmill on two legs and then on four legs, BBC News reported. The oxygen content of their expelled breathe was analysed, their muscle exertion monitored by measuring the force on the treadmill and their gait recorded on video. The same experiment was carried out with humans.

It was found that although the energy expended by the chimps was about the same no matter how many limbs were used, they were more energy efficient if they walked upright, taking longer bipedal strides rather than shorter ones. This fits in with the energy hypothesis as the more efficiently our ancestors moved, the less food they would need. The theory is also supported by evidence from the fossil record that shows the lengthening of the leg as the early humans adapted to take longer strides. David Raichlen from Tuscon University said: 'What those results allowed us to do was to look at the fossil record and see whether fossil hominins [ancestors] show adaptations that would have reduced bipedal energy expenditure.'

Twenty years worth of high resonance sonar images of the English Channel have confirmed the theory that it was indeed a megaflood that severed Britain from the European mainland some 400,000 years ago. Images published in Nature show grooves, some 90m deep, and streamlined geological features that suggest it was a huge body of water moving at awesome speeds of up to 1 million cubic meters per second that was responsible for the formation of the White Cliffs of Dover and the submersion of the land bridge to France, BBC News reported.

During the last ice age, when glaciers extended as far south as north London, the geography of Europe was very different. An isthmus connected Britain with France, damming a giant lake to the south of the North Sea which was fed by glacial runoff from the rivers that became the Thames and the Rhine. Some unknown event caused the breach of this 30m high ridge, allowing a torrent of water to surge over the area that became the English Channel, carving out the forms we see today and ensuring that Britain got its island status rather than remaining a European peninsular.

Dr Sanjeev Gupta from Imperial College who collated the images said: ‘Britain's identity and historical development was shaped by what was essentially a chance geological event. The white cliffs of Dover make that rock ridge and they are so symbolic to Britain's identity. It was the creation of those white cliffs that created Britain as an island’.

Fast forward 200,000 years and jump from the white cliffs to southern Africa, a place that scientists can now more confidently dub “the cradle of humanity”. A study, published in Nature, has found that humans first arose from the African continent rather than from several different regions across the globe, confirming the “out of Africa” theory.

Scientists from the University of Cambridge looked at genetic information from 53 human populations and 6000 skulls from around the world. They found that the further away from Africa the data was from, the less variation there was in the DNA or in the size and shape of the skull. This implies that humans originated in Africa and then eventually migrated, colonizing other regions. In doing so, they thinned their regional populations, reducing the available gene pool and so producing less diverse offspring.

Andrea Manica told the Independent: ‘Some have used skull data to argue that modern humans originated in multiple spots around the world. We have combined our genetic data with new measurements of a large sample of skulls to show definitively that modern humans originated from a single area in sub-Saharan Africa.’

The researchers think that the first modern humans, Homo sapiens, evolved 200,000 years ago and didn’t move on until 55,000 years ago when they finally ventured into Asia, Europe and eventually the Americas and Australia. They overwhelmed our more primitive ancestors, Homo erectus and Neanderthal man, driving to them to extinction, rather than interbreeding.

Environmental groups have raised concerns about the impact that biofuel crops could have on the countryside. It is predicted that by 2020 2.5 million acres of British farmland will be used to harvest crops such as oil seed rape and willow, which will then be used to produce fuel. A report by eleven conservation groups, varying from the Bat Conservation Trust to the Council for British Architecture detail their concerns that wildlife will suffer from lack of food and shelter offered by these crops and that sites of historical importance may be damaged.

They say that while they welcome the move to more sustainable forms of energy production, strict guidelines need to be imposed to reduce the potential environmental damage and more research needs to be done into the consequences of intense farming of these crops. However, the groups acknowledge that this change in strategy could bring some benefits, for example, a rejuvenated wood-for-fuel sector would see the restoration of ancient forests and new conifers planted to help meet its demands.

Abi Bunker, Agriculture Policy Officer at the RSPB, said: ‘This report should serve as a wake-up call to government. Instead of jumping on the bioenergy bandwagon and regretting the damage later, the UK should be developing the bioenergy sector with care, avoiding damage to wildlife and making sure that emissions really are reduced.’ Read more at the Daily Telegraph. For a more indepth analysis of the current state of the biofuel industry and the conseqeunces for the English countryside, come along to the BA Festival of Science this September.

In related news, the rush to develop the biofuel industry has contributed to worldwide grain stocks being at their lowest level in 28 years. In response, the EU Agriculture Commissioner has scrapped the obligatory “set aside” scheme for the coming year. The scheme was introduced as part of the Common Agriculture Policy (CAP) review in 1992 to prevent embarrassing food surpluses, the so called EU “mountains and lakes” and to help ease the over-cultivation and mineral depletion of arable land. The scheme has been credited with aiding the recovery of bird, insect and wildflower populations.

By fixing the “set aside” rule at zero, farmers can choose whether or not to cultivate all their land whereas usually it is been compulsory to leave a proportion fallow. It is predicted that this should increase food grain production of crops such as barley and wheat by 11 to 17 million tonnes, easing the worldwide shortage. Several weak European harvests, an extended drought in Australia and the rise of the biofuel industry have all been blamed for the shortage. It is estimated that industrial grain production will rise by 23 per cent in 2007-2008, reported the Times.

The world’s first eco-computer will be on the shelves by October, its manufacturers, PC World say. The wooden PC is being heralded as the first truly carbon neutral, mass market computer. The company will offset the production and transport carbon emissions, throw in a few energy saving light bulbs, provide no paper manual and could save consumers an average of £29 a year based on 5 hours a day usage. At the same time, the producers promise that it will cost about the same as a standard model and be just as fast.

The computer industry is a well known culprit of environmental crime. Each PC requires ten times its mass in fossil fuels to produce whereas a fridge or car only needs one to two times. They are full of toxic chemicals which contaminate the areas around landfill sites, as with every new electronic device, there is the problem of style obsolescence. It is only ‘new’ until the next model arrives a few months later, leaving tonnes of redundant electronic waste as style conscious consumers rush to upgrade.

It is hoped that if the green PC proves popular it might herald the beginning of the end of our insatiable need for sleek, power hungry gadgetry, reported the Independent.

Other news in brief:

The Chief Medical Officer, Dr Liam Donaldson called for a rethink in the way people go about donating their organs to help reverse the current crisis in which one person dies every day in Britain awaiting a transplant. Dr Donaldson advocated an opt out scheme or “presumed consent” rather than the current opt in method, in his annual report on the nation’s health. He said 70 per cent of people are willing to donate their organs but only 20 per cent actually manage to register, reported the Times.

A link between asthma and obesity has been found by researchers from Kings College London, the Guardian reported. Both conditions have risen dramatically in the last few decades but this is the first time a study has shown they might be connected. Scientists extracted the cells that cause lung inflammation in asthma from obese asthmatics and found that the cells also produced high levels of the hormone, promelanin, which is involved in appetite regulation. However, they are unsure whether this is evidence of a direct causal link or just a vicious cycle whereby the obese person develops asthma and then sees their obesity worsen as more promelanin is produced.

A bionic hand invented by a Scottish NHS worker went on sale this week. The inventor, David Gow told BBC News: ‘It's the first hand to come to the market that's actually had bending fingers just like your own hand’. The digits are controlled by the patient’s muscles making its grip much more autonomous. So far the hand has received rave reviews from those testing it.

Also this week, from hands to paws as the world’s first prothestic animal limb was fitted to a Belgian Shepherd dog. It is special because the dog’s skin has grown into the metal, offering hope for human amputees. Noel Fitzgerald, the veterinary surgeon told the Daily Telegraph: ‘Because it has been implanted into the radius of the forearm of the dog, it will act as a model for human amputees in the future and provides hope for people without feet or hands.’

Genetic variations may be responsible for delaying the onset of AIDS in HIV sufferers, scientists say. There is wide variation in the time period of people being infected with HIV and it overwhelming their immune system to become full blown AIDS, but the reason for this has not been known. Researchers studied the genome of 486 HIV patients and found that people who had three specific genetic variations also had less of the virus in their system. This is exciting as the natural resistance could offer clues for the design of future drugs or even a vaccine. (The Times)

The caste system in the bee hive is chemically controlled, says a report in Science. The queen bee releases a pheromone to keep her nurse drones in check, effectively brainwashing them. The mechanism enables her to maintain her dominance and the hierarchy in the hive intact. Scientists from a university in New Zealand taught drones to associate a certain odour with an electric shock, when the bees were exposed to the odour they bared their stings but not if they had been hit with a whiff of the pheromone beforehand. (The Independent)

And finally:

Scientific evidence for the iPod generation. These days it seems that people can’t get through their everyday lives without being helped along by some kind of musical fix; whether it be to aid concentration, provide a distraction from household chores or perhaps just a bit of escapism during the commute to work. Everywhere you look, people are plugged into their MP3 players and now they have some hard scientific evidence of what they’ve known all along - music makes you feel good.

A rock producer-cum-neuroscientist from McGill University in Montreal, Canada has studied the physiological and psychological effects of listening to music and claims to have found the “sex, drugs and rock’n’roll” site of the brain. His team measured the heart rate, blood pressure, sweat and respiration responses and used scanners to measure brain activity whilst volunteers listened to music. He found that it provoked a release of the “feel good” chemical, dopamine, and triggered other physical reactions similar to those experienced during other more obvious thrill seeking pursuits such as gambling, sky diving or having sex.

Professor Daniel Levitin told the Daily Telegraph: ‘Music is effective at moderating arousal levels, concentration, and helping to regulate mood through its action on the brain's natural chemistry’. He hopes the more we understand the mechanisms at work the more people can take fine tune their choice of track to suit the task at hand, helping them get the most out of their day.