Archives for November 2008

Can you answer this?

Calculate the percentage by mass of phosphorus present in calcium phosphate, Ca3(PO4)2.
Relative atomic masses: Ca = 40; P = 31; O = 16.

No? Well, neither can the majority of the country's brightest 16-year-olds.

The question comes from an O-level chemistry paper set in 1965, and it's just one of 40 from 50 years of exams the Royal Society of Chemistry has put together to test the standard of science teaching in schools today.

Over the summer more than 1,000 of the best students from all over the country sat this extra paper online, and according to the RSC the results "demolish the myth of record-breaking educational performance in science".

The results do make painful reading, and although the winner of the "Five-Decade Challenge" managed an impressive 94%, the average score was just 25%.

Breaking the figures down by decade also reveals an alarming slump in performance over time, with pupils managing to answer 35% of the questions from the 2000s correctly, but only 15% from the 1960s.

The chief executive of the RSC, Dr Richard Pike, claims the results provide hard evidence of a catastrophic fall in the standard of science teaching, and explodes the myth that we've been enjoying a "great leap forward" in education.

"The brightest pupils," he says, "are not being stretched, or trained in mathematical techniques, because they can get an A* grade without doing a single calculation. Conversely, the majority get at least a 'good pass' (grade C) by showing merely a superficial knowledge on a wide range of issues, but no understanding of the fundamentals."

To press home the message the Society has launched an e-petition on the Downing Street website - it's already been signed by 1,500 people - and is sending a copy of the report to every MP.

But even if today's pupils can't answer the questions put to 16-year-olds in the 1960s and 1970s, does that really mean standards have fallen? Professor John Holman from the National Science Learning Centre in York is not so sure. In the first place, he says, the way science is taught is very different. In the past, students were taught a much more limited curriculum in greater depth. Today's syllabus is much broader.

And of course you can't go back in time and get pupils from the 1960s and 1970s to sit today's GCSE exams so the comparison isn't really valid.

By the way, the answer to the question I posed at the top is: 20%. Each molecule of calcium phosphate contains three atoms of calcium, and two sets of one atom of phosphorus and four atoms of oxygen. That gives you a calculation of 40x3 + (31 + 64)x2 which equals 310. The mass of the phosphorus (62) as a percentage of the whole (310) is 20%.

Phew!

High above the tree line in the Rocky mountains of British Columbia, on a ridge running between two jagged peaks, a thin strip of slate grey rock breaks the surface.

To the untrained eye this nondescript seam of sedimentary rock hardly rates a second look, but to palaeontologists, it's worth its weight in gold. The Burgess Shale contains some of the oldest and best preserved fossils anywhere in the world, and offers a unique insight into the blossoming of marine animal life known as the Cambrian explosion some 500 million years ago.

All the more remarkable because the Burgess Shale really shouldn't be there. Everything we know about the geophysical processes involved in mountain formation tells us the intense heat and pressure generated as the rocky mountains were thrust up should have destroyed these fragile deposits long ago.

Instead we're treated to a fantastic array of spiny, bug-eyed and armour plated monsters preserved in the kind of exquisite detail that even includes imprints of their soft fleshy parts - the eyes and internal organs - that almost never survive the process of fossilisation.

So what happened? Why are the Burgess Shale fossils there at all?

To answer that question, Dr Alex Page, at Cambridge University, and Dr Jan Zalasiewicz, at the University of Leicester, have painstakingly re-examined hundreds of Burgess Shale fossils, but this time paying much closer attention to the geophysical processes that were occurring as the shallow seabed these animals inhabited was sucked down into the earth's crust and then thrust back up again to form a ridge in the Rocky mountains.

They've shown that as the delicate organic tissues of these fossilised animals were heated deep in the earth's crust they became the site for clay mineral formation. These new minerals picked out the intricate detail of gills, guts and eyes we see today, enhancing their preservation.

As Alex Page says: "Far from cremating these unique specimens the processes that thrust up the rocky mountains actually baked the Burgess Shale fossils in."

As Claudia Castillo skips up the front steps of the Barcelona Hospital Clinic, or laughs and plays with her four-year-old daughter in the park, she looks just like any other happy, healthy young mum.

Only the thin scar at the base of her neck hints at how remarkable these everyday activities really are. As recently as last June, the trip to the park might have earned her a couple of nights on a ventilator and even a flight of stairs represented a major challenge.

But at a press conference in London yesterday her surgeon Paolo Macchiarini was able to roll his eyes as he recounted how Claudia had recently called him at home at five in the morning to complain about feeling breathless....she was ringing from a disco and had been dancing all night.

This miraculous transformation did not come easily. Teams of scientists from Spain, Italy and Britain have collaborated in a pioneering project to achieve a double first. The first transplant of a trachea (the windpipe) from an organ donor, and the first time a bio-engineered organ has been successfully grafted into a living patient.

First the donated trachea was removed and chemically treated to strip away the living cellular tissue, so that just the collagen framework of the original organ remained. Then in a separate procedure adult stem cells were taken from Claudia's bone marrow and stimulated to develop into chrondrocytes, or cartilage cells.

Using a technique originally developed to treat osteoarthritis, scientists at the University of Bristol stimulated these chrondrocytes to seed, or re-populate, the collagen framework creating a 'bio-engineered' trachea that's a perfect match to the patient.

And finally this new organ was cut and shaped to replace the damaged section of Claudia's windpipe and transplanted into place allowing her to breathe normally for the first time in years.

And because Claudia's new windpipe has been tailor-made from her own cells none of the usual problems associated with transplantation apply. There's no risk of rejection and Claudia will not have to spend the rest of her life on immunosuppressive drugs.

Professor Anthony Hollander whose team in Bristol developed the revolutionary stem cell techniques used to bio-engineer the new organ described the achievement as a significant step forward.

"At last," he said, "we can stop talking about the potential this technology offers...this is stem cell medicine in practice."

Last year 482 people, many of them children, died while waiting for a transplant. Almost as many died after being removed from waiting lists when it was judged they had become too ill to survive a transplant operation.

The simple fact is that Britain has one of the worst organ donation rates in Europe.

While polls show that between 65 and 90 percent of people support the idea of organ donation, only a quarter of adult's names appear on the Organ Donor Register. A mis-match that means the overall number of people on transplant waiting lists - currently more than 8,000 - is rising by 8 percent every year

That's why the Organ Donation Taskforce was set up in January - to look at ways of improving the number of organs available for transplant.

At the time both the Prime Minister and the Chief Medical Officer, Sir Liam Donaldson, appeared to pre-judge the issue - suggesting that thousands of lives could be saved if we switched to a system of presumed consent. A system that saw everyone who did not specifically opt out added to the register of organ donors. Announcing the move Gordon Brown talked about the "aching gap" between the demand for organs and their supply.

But it seems the Organ Donation Taskforce doesn't agree.

In a report to be published later today the Taskforce will reject presumed consent, arguing that a shortage of intensive care staff, transplant co-ordinators, and a lack of funding are the biggest obstacles to improving organ donation rates. Doctors too have raised concerns that a change could undermine people's confidence in the system, and erode the trust between intensive care staff and a patient's relatives.

If the government is worried about the rates for organ donation it seems, persuasion is better than presumption.

Trees are good. They store carbon, generate oxygen, suck pollutants out of the air, provide a habitat for complex ecosystems, promote water storage and rainfall, and (as every lazy lion knows) can even offer a little relief from an unforgiving sun. Ergo: planting trees is good for the planet.

Well, not necessarily. Sadly it turns out that things are not that simple. According to a new report from an international team of scientists it all depends where you plant them.

Too far north and you risk altering the albedo of the planet by replacing sunlight reflecting white snow with heat absorbing dark green. In the mid-latitudes the pros and cons are more finely balanced, and you need to make sure that extensive aforestation (that's converting open land previously used for crops or grazing to woodland) doesn't disrupt other ecological activities leading to an overall increase in greenhouse gas emissions.

By and large, planting trees in warm temperate regions and the tropics is most likely to succeed in reducing the global temperature, but - again - you need to be careful about the wider biophysical impact.

And getting it right matters because aforestation is an increasingly important part of the international carbon trading scheme. Big polluters can offset their emissions by planting trees or paying someone else to plant trees for them.

Today's report, published in the journal Environmental Research Letters, shows that simply throwing money at well-meaning tree huggers doesn't go far enough. Each individual aforestation scheme needs to be assessed against its overall impact on the environment.

Lead author Rob Jackson from North Carolina's Duke University says simple rules need to be developed to encourage best practice.

"Ignoring this challenge could result in millions of dollars being invested in mitigation projects that provide little climate benefit or, worse, are counter-productive," he says.

Just stop for a moment and consider what it means to be able to manipulate matter at the level of individual atoms.

Think how smooth you could make a surface, how sharp an edge or strong a fibre would be, how much more efficiently a chemical process might perform if each individual component was optimally aligned.

You're beginning to get an idea of the enormous potential nanotechnology offers. And it's a potential that industry has been quick to seize. From a standing start in 1990, the Woodrow Wilson Centre for Nanotechnology's database now lists more than 600 nanomaterial products already available in the global market place.

Things like the roof of the new St Pancras station, which is made of self-cleaning glass (it's coated with a nanomaterial that reacts with sunlight to breakdown dirt), or the sports gear that's impregnated with silver nanoparticles.

No, it's not a bling thing. Silver is a powerful anti-bacterial and these microscopic terminators poison the bugs that make your gym kit reek.

The problem comes when that silver impregnated material begins to degrade in your washing machine. Those silver nano particles are going to get washed out into the wider environment, and we don't really know what the consequences will be.

Although today's report - Novel Materials in the Environment: The case of nanotechnology - found no evidence of harm to human health or the environment, the Royal Commission on Environmental Pollution does raise serious concerns about our lack of understanding - the 'unknown unknowns' as the Commission's chairman Sir John Lawton put it.

It's the classic control dilemma. A new technology with obvious benefits emerges, but we really don't know anything about the long term risks associated with it. By the time hard evidence of a problem manifests itself that technology is already well embedded and doing something about it is much harder. Just think of asbestos, or organo-chlorine pesticides like DDT, lead in petrol or CFCs in fridges...the list goes on and on.

If we want to avoid a similar pattern with nanotechnology we need to start thinking about the long term impact of novel processes and applications now.

At long last (they first threatened to do it more than 4 years ago) European Commissioners have published plans for a comprehensive overhaul of the rules governing the use of animals in medical experiments.

And at first glance it looks like a significant tightening of the legislation. Launching the draft directive Environment Commissioner Stavros Dimas said it was time to "....steer away from testing on animals. Scientific research must focus on finding alternative methods to animal testing".

The top line is certainly the ban on experiments on the great apes - our closest relatives - but the proposal includes important caveats....research involving gorillas, chimpanzees and orangutans will still be allowed in exceptional circumstances (such as a serious pandemic threatening human health), and for the conservation of great apes themselves.

There are also stricter regulations governing the use of other non-human primates, measures to phase out the use of wild-caught animals, a significant widening of the directive's scope to include invertebrates; and a whole series of new rules governing the housing and welfare of captive animals in medical facilities.

Underpinning the draft directive is the principle of the 3R's - reducing the number of animals to a minimum, refining experiments to alleviate suffering, and replacing animals with alternatives wherever possible. It's an approach that has been pioneered here in the UK, and some are already referring to the plan as a Europe-wide adoption of "the British model".

That approach was given a cautious welcome by scientists here: The Research Defence Society's Dr Simon Festing called the draft proposals a "very good first stab", but warned against a significant increase in the bureaucratic hurdles facing researchers. The new proposals should promote animal welfare, but not compromise the good science we all want.

More than 12 million animals are used in research across Europe every year, and animal rights campaigners have been lobbying for reform since the original directive came into effect in 1986. Last night the BUAV congratulated the Commission for seizing a 'once in a generation' opportunity, but criticised the loopholes in the ban on great apes, and questioned what commissioners meant by "transitional periods" when it came to the ban on wild-caught monkeys.

And for those who want to see an immediate end to all experiments involving animals of course, this is not so much a 'once in a generation' as a missed opportunity.