What is Quicksand?

There was a time when almost every action movie seemed to involve the hero or villain becoming swamped in quicksand, sinking away until only their hat remains on the surface; even Flash Gordon and vine-swinging ape-man Tarzan were victims during their careers.

But contrary to what Hollywood would have you believe, it’s actually impossible to drown in quicksand, but almost as impossible to escape, as a Dutch scientist found when he produced his own home-made variety in the laboratory.

Daniel Bonn was on holiday in the Iranian province of Qom when he saw a sign saying "Danger: Quicksand". Local shepherds had told him that, periodically, camels and people (usually those who had dared to disagree with the local regime) had disappeared in the area. Realising that science didn’t actually have an answer to the quicksand conundrum, he took some samples home with him.

So what is quicksand made of?
Analysis of the composition of the "quicksand" showed that there are four key ingedients – sand, obviously, water, clay and salt. Together these materials form a structure resembling a house of cards, with large water-filled gaps between the sand particles, which are loosely glued in place by the clay.

As long as it’s left alone, the structure remains stable. But as soon as it’s disturbed, by stepping on it, the clay changes from a jelly-like consistency to a runny liquid. The effect is the same as stirring a pot of yoghurt. Liquefying the clay makes the quicksand about one million times runnier, and the whole house of cards comes tumbling down, with you inside it.

Very quickly, the sand sinks to the bottom and the water floats to the top. This is where the salt comes in. When there’s enough salt present, as soon as the clay particles liquefy, electrical charges make them begin to stick together to form bigger particles and these also settle with the sand.

The result is a very stodgy layer of sand and clay, which is twice as dense as the original quicksand and packed tightly around the trapped body parts.

So how do you escape?
Well certainly not the way Hollywood would have you do it – by being pulled out by a horse – because Daniel Bonn’s measurements show that the force need to extract a trapped foot (ten thousand Newtons) is equivalent to that needed to lift the average family car. You’d probably escape, but minus your legs.

The best way out is to try to re-build the house cards around the trapped body parts. Making small circles with each part of your body re-introduces water between the sand and clay particles, reducing the density and making it easier for someone to heave you out.

But everyone apart from a Hollywood director can take solace from the most important finding of the research – that it’s impossible to drown in quicksand – you should only sink half way. The density of quicksand, at 2 grams per cubic centimetre, is twice the density of a human (1 gram per cubic centimetre), so stuck you might be, but drowned you wouldn’t!

Original Reference:
Khaldoun, Bonn et al., Nature 437; pp 635

Chris Smith

Do Bald Men get all the Girls ?

This is science, not science fiction. Research has shown that bald males command a larger harem of females than their hairier counterparts...that is, if the bald male is a maneless Tsavo lion from Kenya. In humans, male pattern baldness (or androgenic alopecia) has been linked to a number of biological pathways.

I will only focus on the best publicised cause, an over-responsiveness to DHT, or dihydrotestosterone for those who enjoy long words. This hypersensitivity may be due to a number of factors. For instance, high levels of the receptor for DHT on hair follicles, or a characteristic and more sensitive structure of the receptor in predisposed people, can cause the hair follicle to detect more DHT than is good for it. In fact, one proposal for why hair is lost in a particular pattern (hence the term male pattern baldness) is because hair follicles in the regions of typical hair loss normally express higher levels of the receptor. Chief among the culprits though, at least according to current thought, is an overproduction of DHT. The enzyme 5-alpha reductase converts testosterone into DHT. In people predisposed to baldness, the levels of this enzyme is often raised in the scalp and skin, resulting in a higher concentration of DHT that can attach to the receptors on hair follicles. On the flip side, if you have average levels of 5-alpha reductase but high levels of testosterone, it may also be possible to get more than a healthy balance of DHT, but this hypothesis is somewhat more controversial. But in support of this idea, although the pattern tends to look slightly different, women can also exhibit male pattern baldness. Normally, oestrogen counteracts the effects of testosterone, but after menopause a woman's oestrogen level falls and her testosterone (yes, women produce this 'male' hormone too) can now be turned into DHT and cause hair loss.

DHT is thought to promote hair loss in three ways: 1) Healthy follicles grow hair for a time, usually for 2-5 years, and then take a break before starting to grow hair again. DHT shortens the hair growth time and increases the follicle's hair growth holiday. This results in fewer new hairs and shorter ones at that. 2) Immediately before a healthy follicle stops hair growth, it shrinks and the hair it produces is thin and weak (vellus hair). DHT causes the follicle to shrink prematurely which is why bald people have peach fuzz on their heads. 3) Follicles need a blood supply to be nourished. DHT may cause less blood to flow to the follicles.

Bald lions
So where do the Tsavo lions come in? Unlike balding men, Tsavo lions do not lose their pre-existing hair - their manes just never grow. Nonetheless, it has been suggested that they are subject to something akin to male-pattern baldness because their manelessness may be caused by elevated levels of testosterone. This is only a hypothesis; the field work testing hormone levels of these lions has just been started a few months ago. However, maneless Tsavo lions have a reputation for being extremely aggressive, a trait linked to high testosterone. If they do have more testosterone than the average African lion it seems reasonable to suggest that more of this hormone is turned into DHT, which stops their manes from growing due to the three biological actions listed above. It is important to remember though that this may not be the cause of their baldness. Even if their testosterone levels are high, there may be other more important genetic reasons for their lack of manes. Male Tsavo lions live in two types of social groupings: Adults roam as the sole male among a very large number of females in a group called a 'pride'. This is an unusual social structure for lions since there are usually at least two males in every pride. Another bizarre social feature of these lions is that nomadic males stick together. This is very thought-provoking, particularly when it is realised that males in a pride actively do not allow other males to join. Why would some lions not tolerate other males while others seek their companionship? The idea is that these are coalitions of adolescent males that hunt together, but once their testosterone levels peak, they become too competitive and the group splits up.

Bald and a social outcast, or a sex magnet ?
Whether or not the attitude could be proven accurate statistically, there is a common conception out there that human females find bald men less attractive. Adult Tsavo lions don't seem to have that problem though. Not only does one guy get ALL the girls, but he gets more girls than the other African lions with hair would even if they were the only male in their pride. So, is this social construct a female choice or a male choice? Do the females choose to cluster around the bald male, truly making the group a 'male pride' or is the bald male forced to live only among females because there would be too much competition amongst other adult males? Unless we learn to speak Lion Lingo and question the lions directly, I suppose we will never know the answer to that question with absolute certainty. I am no zoologist, so it is possible that testosterone levels have nothing to do with social groupings, or manelessness, among Tsavo lions and it is just a peculiarity of this group.

But what if the social grouping of bald animals did have something to do with testosterone...perhaps if it we looked into it more closely, we would find something similar in humans. Perhaps men whose hair loss stems from other non-hormonal causes really ARE less attractive to women because, well, females like hair. In essence, nothing more than cosmetic squeamishness. And perhaps men whose hair loss is hormonal are MORE successful with the ladies because they send out invisible signals (pheromones) responsible for chemical attraction. Or perhaps they don't get along well with other males with clashing hormonal profiles and have had to learn to understand women better instead. Naturally, this is all speculation on my part, but it makes you wonder what lions from some remote part of the world could potentially teach us about ourselves and our dispositions !

Dalya Rosner

Ricin : The Secret Assassin

The recently discovered traces of ricin in a makeshift laboratory in a flat in London have caused a media frenzy over its potential use in a terrorist attack. Ricin was most famously used in the assassination of the Bulgarian dissident Georgi Markov when a platinum ball containing the poison was injected into his leg from the tip of an umbrella. He died three days later on 10 September 1978. The ricin-firing umbrella was developed by the Soviet secret police and was used to kill at least three other Bulgarian defectors and an attempted assassination of a fourth, again in London.

Ricin itself is made from a naturally occurring protein produced by the castor bean plant and the way that it exerts its toxic action in the body is a story of subterfuge and deception to rival the Cold War umbrella assassinations.

The ricin molecule contains two main parts; one acts as the weapon, the other as a disguise.

The weaponry consists of a protein molecule whose job it is to prevent other proteins from being made. A protein is just a large natural molecule which has a particular job to do in the body (e.g. hemoglobin is a protein whose job it is to carry oxygen around the body) and the instructions for making these proteins are contained within our DNA. Ricin sabotages the machinery within the body that turns the instructions in DNA into functioning proteins. Without these proteins cells cannot function and die. As a result the organs in the body that are exposed to ricin start to fail. If ingested (eaten), ricin causes severe gastroenteritis and hemorrhaging followed by failure of the liver, spleen and kidneys. If breathed in, the symptoms include weakness, fever, cough, pulmonary oedema (fluid collecting in the lungs) and respiratory distress. In severe cases exposure to ricin can cause death.

The body is not without defences and one of the simplest is just to deny entry of toxins into our cells in the first place, but that is where the disguise comes in. Each cell has to let some molecules in and out in order for it to work together with the cells around it. The second part of ricin is a disguise so that when the poison encounters a cell it goes to the door where molecules are let in and is recognized as a friend. Only when it has managed to gain entry into the cell does ricin discard its disguise and use its weaponary to sabotage the protein-making machinery.

Interestingly, ricin is toxic to the very plant that makes it, but the plant overcomes this toxicity by making ricin as one long molecule incorporating both disguise and weapon stuck together in such a way that the disguise can not be taken off. Only when the ricin is excreted are ties that bind the disguise to the weapon loosened to allow the toxin to perform its deadly deception.

Martin Westwell

Deadly Cone Snails (Conus) Harbour Painkillers of the Future

"I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me." Sir Isaac Newton (1642-1727)

Snails. Yes, I know, it's hard to get excited. You think snail, you think, slime. You think slow, squidgy, meandering ball of wibbly-gloop. With eyes on stalks. Then again, you might just think of garlic. Snails are pathetic English garden munchers!

Or are they? Not all snails are born equal. Some snails are born with heightened killer instincts, roaming beneath the ocean's surface, waiting, hunting for that one precious meal. And we're not talking limp lettuce - some snails are content with nothing less than bagging an entire fish! And should you, my friend, be unlucky enough to disturb one of these molluscs whilst out having a leisurely paddle, you could be well on your way to the great paddling pool in the sky.

Great White sharks are passé, welcome to the world of the genus, Conus…

Collecting beautifully patterned Conus snails off the north east coast of Australia might sound like hard work, but it's not all boats, sun, fresh air and sea. Dr Bruce Livett of Melbourne University takes it all in his stride, though. For nearly a decade, he and his team of enthusiastic colleagues, students and friends have sought and studied these spectacular snails.

But why is a neuroscientist interested in these animals? Because, apart from their spectacularly patterned shells, these molluscs have a secret weapon - one that may revolutionise the treatment of pain. A typical poisonous snake might unleash a couple of different nerve toxins on its furry victim; but what the Conus lacks in speed, it more than makes up for in poison. These snails are positively brimming with nasties, often shoving around 50 individual toxic mini-proteins into their victim.

Your brain, under normal circumstances, is a finely honed thinking machine. The reason being that all of its nerves are able to function correctly, sending messages, receiving messages, processing the information and giving a pretty good output. If the brain is like an organic computer, then being stung by a Conus is a bit like pouring a pint of ale on a laptop. Fizz, bang, splutter, dead.

The reason is that each of the tiny proteins that make up the toxic cocktail are targeted at different parts of the nervous system: these snails don't just 'blow the bloody doors off' your brain, they terminate it from every conceivable angle!

But not all the components in the venom are deadly. Some turn out to be good for you. As they say "no pain, no gain". So what about the future of pain? Painkiller research can be riddled with problems: side-effects, dependency, efficacy. What about a painkiller that is as effective as morphine but has no apparent side-effects? The relatively few humans who have witnessed a death-by-snail have noted the absence of pain. And Bruce Livett and his team now know why.

One of the toxins in the sting of the Conus victoriae species, is a string of just 16 amino acids (the Lego units that make proteins). This tiny protein, ACV1, binds to bits of the brain that would normally allow us to feel pain, and shuts them down. What we potentially have here is a powerful new generation of analgesics. This new 'drug' has done very well in pre-clinical trials and is now undergoing toxicity tests prior to entering clinical trials, the rights for development into a drug having been bought by a company called Metabolic Pharmaceuticals.

So, spare a thought for our British, plant bound relatives. Maybe they deserve a little more respect. After all, with relatives like the Conus, you don't need to be pretty.

"It is perhaps a more fortunate destiny to have a taste for collecting shells than to be born a millionaire."
Robert Louis Stevenson (1850-1894)

Barry Gibb

The Art of The Barbecue

Although the summer appears to have ended, I thought I would deal with something that provides a perfect opportunity to marry good food and wine: the barbecue.

What we mostly remember are alcohol fuelled, sun kissed days with our friends. The food on the whole is pretty ordinary, the standard fare being a variety of dried out, blackened sausages, burgers which consist of mostly bread, the dreaded vegetarian alternatives and meat off cuts. The worst are pre-marinated supermarket gloops with such exotic names as "honey, lime and ginger glazed chicken". By necessity these are often last minute affairs and we compensate for lack of quality with vast quantity (another example of our increasing Americanisation).

It doesn't have to be this way! By following a few basics barbecues can become fantastic fun AND provide great food.

The first pre-requisite is a decent barbecue. Aficionados will tell you the Weber kettledrum is the gold standard. Tedious arguments about the respective merits of gas vs. coal abound. In my experience although good gas barbecues are more user-friendly, these never quite match "coal kettles" for the unique flavors they impart on food. The other essentials are to source good quality raw materials and choose strong and sympathetic flavours but keep them simple. At two recent barbecues we had a near perfect whole leg of lamb which had been stuffed higgledy-piggledy with a mixture of bashed medjool dates, cumin and coriander seed and plenty of garlic mixed with good olive oil. The surface was smeared with preserved lemons mixed with cumin seed, salt and black pepper. This acquired fantastic smoky North African flavours with a slow roast over a bed of celery. Even more unique was a "stiff fresh" big turbot I lovingly brought back from Cornwall. We simply clipped its fins, placed it on a bed of sliced potatoes and fish stock, then barbecued it with plenty of slices of herb butter on top. The chunky, pale and flavorful flesh of the turbot took on the barbecue flavors as well as the herb butter and was utterly gorgeous.

This may sound like "posh-nosh" but was quite simple to prepare, even after work, mid-week! Speaking of turbot reminds me of my recent "surfing" trip to Padstow. We ate at Rick Stein's, which was as good as ever, although my last meal there on Sept 11th 2001 became memorable for all the wrong reasons. A poached hunk of skate with oodles of Moroccan flavours was particularly enjoyable, accompanied by a Grosset Polish Hill Riesling 1999 which was chock full of lime blossom, mango, hints of petrol (a compliment, really!) and racy acidity.

If you go to this lovely area though, please go to the Beach Hut at Watergate Bay. Run by a bunch of "extreme sport" dudes, the location is unbelievable, with views that would do California proud. More amazingly the food, whilst unpretentious, concentrates on prime seafood which has just stopped breathing and is consistently excellent. The service is relaxed and the prices very fair, although the wine list could do with a little beefing up. This is one of the best non-kept secrets of foodie Britain and daily flights from Stansted to Newquay bring it within range of long weekends...

So to barbecue wines…

La Spinetta Bricco Quaglia Moscato d'Asti 2001. Lovely grapey overripe fruit flavors with gentle froth and sweetness. Great aperitif or fruit salad wine (£8.00 in Noel Young, Cambridge. If you want a cheaper alternative Villa Jolanda from Tesco (£3.00 this month) is not bad).

'Vixen' Fox Creek NV. The ultimate barbecue wine. Creamy black cherry with spice and bubbles! Shiraz with bubbles? Stop being a snob and try it! (£11.00 in Noel Young, Cambridge).

Bollinger NV. My favourite champaign. Yeasty and meaty stuff with good acidity. Widely available at £22-26.

Soave Classico 2001 Pieropan. Not like your usual sugar and vinegar water Soave. Full of apricot and overripe melon, unctuous body and no acidity so not for keeping (around £8.50 Noel Young, Cambridge - pricey but well worth it).

Kleos Luigi Maffini 2000. Yummy smoky, blackberry jam and raisins. Classic bitter-sweet Italian flavors with plenty of guts to last. (£9.49 in Noel Young, Cambridge).

Tower Estate Shiraz 1999 Barossa and Hunter Valley. Who says vintages and regions don't matter in Oz? Both from the same estate but one is full on, with lots of spicy black cherry and oak while the other is more refined, leathery and cassis dominated. Both are good value at £12-13 from Rick Stein's deli.

Varuna Aluvihare