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Podcast TranscriptThe Naked Scientists: Science Radio & Science Podcasts |
| 30th Nov 2003 | < Previous Show | Next Show > | |||||||||||
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Water From Ancient Rocks Clue To Life’s Origins
Fossils can tell us an enormous amount about the kinds of things that were living on the earth before we came along, but fossils can’t tell us everything. That's because the fossil record becomes less reliable the farther back in time you go. So scientists at the universities of Aberdeen and Glasgow have hit upon the idea of analysing traces of water that have been trapped inside rocks for millions or billions of years. The scientists hope that the water will contain a chemical ‘snapshot’ of the conditions on earth at the time when the water was locked away inside the rock, and possibly also substances called ‘biomolecules’ – the hallmarks of life – providing us with an insight into early life on earth. The technique could also be used to analyse meteorites from outer space and the scientists are working on the possibility of building a miniature version of the machine that could be sent on space-craft to other planets.
30th Nov 2003
No More Fruit Squeezing
Shoppers may no longer need to squeeze their pears to test if they are ready to eat. A new label developed by researchers in New Zealand, is designed to change colour and show you when your fruit is at it’s best, without any squeezing needed. It does this by reacting to different levels of gases that fruit emit while they ripen, changing colour accordingly. So far a label is being tested for pears, which are notoriously difficult to tell when they are ripe, and if that takes off then the researchers are planning versions for kiwi fruit, avocados and melons.
30th Nov 2003
Oxygen Sensitive Dye To Detect Unsafe Food
Scientists at the University of Strathclyde have developed an oxygen-sensitive ink that to warn you that food packaging is leaky. Food is normally packaged in a protective oxygen-free atmosphere containing nitrogen or carbon dioxide which helps to keep the food fresh. The new ink, which is colourless, turns blue when it comes into contact with oxygen. So a blue spot on the inside of the food packaging would alert you that the packet is leaky. The new ink consists of a dye called methylene blue, and nanoparticles of titanium dioxide. When the dye is activated with ultraviolet light it becomes colourless, but when it comes into contact with oxygen, it goes blue again.
30th Nov 2003
How Fruit Can Protect You From Cancer
We’ve all heard the advice to eat our five portions of fruit and vegetables a day, as they contain vitamins and minerals essential for our health. Now some new studies have suggested that fruit extracts might provide protection against skin cancer. When tested on mice, pomegranate extract significantly protected them from developing skin cancers in response to skin-damaging chemicals. Another molecule, perillyl alcohol (found in cherries, mint and citrus fruits) protected cells from the damaging UV rays found in sunlight, indicating that it might be of future use in sunscreens. Finally, one of the chemicals in grapes, resveratrol, has been known for some time to have anticancer effects when incorporated into wine, but American researchers have now shown it can protect against UV rays. The researchers suggest that more research should be done to out resveratrol into skin products, and also recommend moderate consumption of grapes and red wine (Bio.com).
30th Nov 2003
Cinnamon Can Lower Blood Glucose
There’s some good news for sufferers of diabetes these week, with research revealing that eating just half a teaspoon of cinnamon a day can significantly reduce blood sugar levels. American researchers discovered this by accident when looking at the effects of common foods on blood sugar. They tested apple pie, expecting to see a bad effect, but found that the cinnamon in the pies was in fact helping. People with Type 1 diabetes don’t produce enough insulin, the hormone that makes cells in your body convert the simple sugar glucose either into fats for storage or into energy. Type 2 diabetics produce enough insulin, but are not sensitive to it. Either way this leads to high levels of glucose in the blood which can lead to long-term damage to the eyes, kidneys, nerves and other organs. the active ingredient in cinnamon turns out to be a compound called MHCP, which does acts in the same way as insulin. In trials, a group of Type 2 diabetics were given supplements of cinnamon and showed on average 20% lower blood sugar levels, as well as decreases in the levels of fat and bad cholesterol. So you can add cinnamon to your normal diet, by sprinkling powdered cinnamon to your toast, coffee or cereal. The effect can even be produced by soaking a cinnamon stick in your tea.
30th Nov 2003
Can Green Tea Prevent Hiv Infection ?
Green tea is slightly different from your average cuppa. It is made from the leaves of the evergreen Camellia sinensis plant, and is touted by many people as a bit of a wonder-drink, preventing cancer and heart disease. It contains chemicals called catechins, especially one called epigallocatechin gallate, or EGCG. This chemical is thought to be responsible for the health benefits of green tea. Now researchers in Texas have found that EGCG can stop HIV, the virus that causes AIDS, from binding to cells in the immune system. This binding is the first step in HIV infection, so if it can be blocked, then HIV infection might be avoided. But the researchers stress that drinking green tea is not enough to avoid HIV infection- as the amounts of EGCG they used in their experiments were many times greater than the amount you get from a cup of tea. But they think that agents based on EGCG, or which work in a similar way, might form the basis of new anti-HIV drugs in the future.
30th Nov 2003
Researchers Discover Man's Oldest Habit
How long have people been cleaning their teeth ? Well, if palaeontologist Leslea Hlusko from the University of Illinois has got it right, the answer could be over 1.8 million years making it the oldest human habit yet recorded ! Indeed the teeth of our ancient relatives are often found to have curved grooves a couple of millimetres wide on their roots which, it has been suggested, were made by primitive toothpicks. But critics of this toothpick theory point out that today’s toothpick users have no such grooves. But what about if the grooves were made by something more abrasive than the wooden picks we use ? Hlusko thinks that the culprit might be grass stems. They are the right size to cause the grooves and, unlike wood, contain abrasive silica particles which are quite literally like sand-paper. Obviously the ultimate test is to try out the theory, so Hlusko spent 8 hours rubbing a tooth from a baboon, and 3 hours rubbing a grass stem against a human tooth. In both cases the grass left marks almost identical to those seen in early hominid teeth.
30th Nov 2003
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