Just give me a second…

On the 30th June 2015 an extra second was added to clocks across the world. Seeing as you now have all of this extra time, here’s everything you need to know about the leap second…

  • The leap second arises because the atomic clocks that we use today are actually more accurate than the earth at time keeping – one million times more accurate to be exact.
  • Changes in the Earth’s orbit are influenced by a number of factors: from an occasional wobble to a gradual slowing of its rotation. This causes the Earth to speed up and slow down unpredictably and is the reason why we need to add leap seconds.
  • A total of 27 leap seconds have been added since 1972 when the idea was first introduced.
  • The last leap second was added at midnight on December 31st 2016, but due to the unpredictability of the Earth’s orbit I can’t actually tell you when the next one will be!
  • Don’t worry though, all electronic devices are updated automatically so long as they’re connected to the internet.

You can listen to the 2015 announcement with the Naked Scientists here.

Climate Change will increase Turbulence on Flights

We’ve seen many recent extreme weather events – from mudslides in Columbia to flooding in Australia – which scientists say are a consequence of climate change; but it’s not just the weather that is affected. The Earth’s atmosphere is made up of several layers of air which all flow around each other in patterns known as jet streams and an increase in temperature will cause these to speed up. This is bad news for air passengers, including the 1 million people currently airborne at this very instant, because an increase in the speed of the jet streams will cause more turbulence making flying less comfortable and potentially more dangerous. I spoke to atmospheric scientist Paul Williams…

  • Climate change will cause a 59% increase in light turbulence, 94% increase in moderate turbulence, and 140%  increase in severe turbulence.
  • Turbulence is measured on a scale from 1 to 7 where 1 means light turbulence, 3 means moderate, 5 means severe, and 7 means extreme.
  • Light turbulence is a slight strain against the seat belt, moderate turbulence causes unsecured objects to become dislodged and makes walking around difficult, and severe turbulence results in anything that isn’t strapped down being catapulted around the cabin.
  • Turbulence is caused by wind shear – the higher you go up into the atmosphere the windier it gets – and instabilities within these layers of shear generate turbulence.
  • As the atmosphere is heated, the temperature increase causes the jet streams to move faster, creating more wind shear and thus more turbulence.
  • The researchers hope that results such as this will encourage us to think more carefully about our carbon footprint as there are likely many effects of Climate Change that we do not know about.

You can listen to the full interview for the Naked Scientists here.

Purging the Detox Myth

We are now just over a week into the new year, how are those resolutions going? If like me you felt bad for (at least) a week’s worth of pigging out over the holiday season, then maybe you’ve been on a detox? They are a quick easy way to get healthy right? Yeah about that…

Most people think of a detox as some form of cleanse that removes various toxins from the body, usually after a period of excessive eating and drinking. While not completely incorrect, the use, or misuse, of the word nowadays is the result of very clever marketing. The correct definition of a detox is a medical procedure that removes dangerous and often life-threatening levels of drugs, alcohol and poisons from the body carried out by a trained medical professional in a hospital or clinic. Not quite the same as drinking some carrot juice then. What we’re doing is more of a ‘cleanse’.

The idea of cleansing the body isn’t new, but the way we do it has changed dramatically. Go back 100 years and we were using therapeutic vomiting, blood-letting and a process known as ‘smuding’ where smoke from burning sage is waved around the energy field of a person to destroy negative energy. These days it’s all intestinal cleaning, foot sponges which supposedly draw out toxins and coffee enemas (yes you read that correctly). The question is does detoxing (or cleansing) really do anything?

Let’s take a simple example: a master cleanse diet favoured by a number of Hollywood celebrities. Begin the day with a litre of warm salt water, consume 2 litres of a concoction of water, lemon juice, maple syrup and cayenne pepper throughout the day and finish with 250ml of laxative in the evening. Do this for 10 days and you will gain energy, lose weight and relieve symptoms of chronic conditions such as arthritis. Except you probably won’t. There are no data on this diet in the medical literature and similar studies on fasts and extremely low-calorie diets actually result in rapid weight gain following their completion. You will of course lose weight during the diet as you are only consuming 600 calories a day, but this is mostly due to fluid loss. Furthermore, the diet is lacking in protein, fatty acids and other essential nutrients, with the daily laxative regime likely to cause dehydration. Just this week doctors in the UK issued a health warning about the potential harms of undertaking a radical new year detox, highlighting the example of a 47-year-old woman admitted to intensive care following a detox diet of herbal remedies and water, that left her with dangerously low levels of salt in her body.

A search of medical literature using the words ‘detox’ and ‘clinical trial’ returns nothing. Quite simply there is no credible evidence to demonstrate that detox kits do anything at all. Perhaps most importantly they have not been shown to offer any of the supposed health benefits claimed by manufacturers and promoters. This may seem a little doom and gloom for the new year, but don’t worry, your body has got you covered. The human body is the best detoxing solution available and here’s how it works.

Let’s pretend I’m one of these mysterious ‘toxins’ trying to enter your body, cleverly concealed in your favourite alcoholic beverage. First up, I pass through the stomach and into the intestines, where I am confronted with lymph nodes called Peyer’s patches. These guys screen out parasites and other foreign substances before they are absorbed into the blood along with nutrients. Well, what if I disguise myself as a nutrient? Now I’m in the blood and ready to do some damage. But what’s this? An army of cells and molecules sent by the immune system are here to fight me off. They are specifically designed to recognise foreign substances and eliminate them from the body, making me target number one. Okay, well, suppose I somehow survive the onslaught from the army of cells, things must surely start to look up? Afraid not. The blood is passed through the liver where proteins called metallothioneins act to neutralise harmful metals and enzymes process drugs. The job of the liver is basically to break down anything that can cause harm to your body, which is bad news for me as a ‘toxin’. If by some miracle there is anything left of me after the liver has worked its magic then I will enter into the kidneys. These are the body’s natural filtration system and remove any waste substances that remain. I think it’s safe to say I’m done for…

If after all of that you still think the so-called ‘toxins’ have a chance, then by all means please do try that coffee enema, but if it were up to me I’d trust my body. The best new year detox plan is simply to concentrate on giving your body what it needs to do its job. That means a healthy diet, regular exercise and sufficient sleep. It might be less exciting than that Colon Detox Pro yoga session you had planned, but it also might actually work…

You can listen to the full interview for the Naked Scientists here.

Growing human hearts

Growing a human heart from a single cell may seem like science fiction, but scientists at the Gladstone Institute at the University of California San Francisco, have taken a huge step forward, by producing the first three-dimensional, beating, human heart chamber. Previously, it had been possible to produce a two dimensional sheet of beating heart cells, but to really gain an understanding of heart formation in a developing foetus and perhaps more importantly, how drugs given to women during pregnancy may affect this development, a three dimensional structure was needed. By treating stem cells with drugs and then confining them to a very small spherical geometry, Bruce Conklin and his team have managed to grow their very own three dimensional model of a human heart, as he explains…

Bruce – the cells around the edge became fibroblasts – a particular type of cell that you use to heal wounds and then only in the very centre were cardiac cells that beat. What this is forming is more of a little organoid is what we call it, where there’s beating cells but there’s also multiple other cell types and that’s what makes it so interesting is that these cell types are somehow talking to each other and somehow collaborating in some way so that they can actually make this structure that we didn’t expect.

Tom – It’s almost like they’re trying to form a heart…

Bruce – That certainly is the impression. They’re heart cells, they’re forming cavities so it could be a model of how parts of human development occurs, but it certainly is not a real human heart in the sense that there’s probably many things that we’re missing. We just have a simplified version with just one chamber, but having it in a controlled way where it happens the same way over and over again we can start asking questions about ‘how do these cells talk to each other?’ So once you have a system which is reproducible you can do experiments to break it in some way or to enhance it in another way.

Tom – What are the applications of this work then?

Bruce – The most obvious application of the work is to study human development. How do cells actually form a heart is something of basic interest. And also, the most common form of birth defects is actually cardiac defects. But the other application is that we can expose these developing human micro-chambers to drugs which are thought to cause developmental defects, specifically of the heart, and in fact one of the key experiments in this study was to use the drug thalidomide which is notorious for causing birth defects. When we expose these cells to the thalidomide they had a dramatic change in the morphology so that you could see that it was altering the developmental process in this micro-chamber. Thalidomide was tested in rodents before it was tried in people and there were no cardiac defects in the rodents. I think that more and more we’re thinking how do we get tests which use real human cells so that we can actually make safer drugs. And in this case say you turn back the hands of time and you had this sort of test perhaps you would have discovered that thalidomide was dangerous before it had gone on to be given to people.

You can listen to the full interview with the Naked Scientists here.

Can you pee on the moon?

Question

If, in some miraculous way, one were able to pee standing on the surface of the Moon, what kind of arc would it create?

Answer

Dr Chris Messenger from the University of Glasgow was on hand to help me with Michael’s question…

  • The moon’s gravity is 16% of that on Earth, which means the pee will travel in a straighter arc and about 2.5 times further
  • In a uniform gravitational field objects travel in a parabolic arc – sort of a ‘u-shape’
  • On the moon, the atmosphere is so thin that the pee would follow a very accurate parabola, as can be seen with the dust thrown up by the lunar rover
  • The low atmospheric pressure on the moon would immediately boil the pee which would then fall to the surface as steam
  • Despite the low temperature of the moon (as low as -170 degrees Celsius), the pressure reduces the boiling point of water so dramatically that your pee would boil way below body temperature of 37 degrees Celsius, which is why it immediately turns to steam
  • The freezing temperature of water on the moon also occurs in the same range as the boiling point, which means that the steam molecules will then freeze into yellow ice crystals

You can listen to the full version of Question of the Week with the Naked Scientists here.

Can ants feel pain?

Question

Carol asks: Can ants feel pain?

Answer

I went crawling around for the answer with York University’s Eleanor Drinkwater…

  • Ants can sense that they’ve been harmed and react but this is different to actually feeling pain
  • Nociception is the sensory nervous system informing the brain that you’ve been hurt, whereas pain is an unpleasant sensation with a negative emotional response
  • One can occur without the other eg. when playing sports you often don’t realise that you are injured until afterwards, or people who have lost limbs experience phantom limb pain
  • Robots can also be programmed to experience nociception without experiencing pain, for example in the video game The Sims characters will jump around if they’re burnt by fire
  • We currently know very little about insect expressions of pain, but we do know that the pain expression systems are different to those in mammals, meaning that insects are likely to experience pain in a different way to humans
  • In short, the jury is still out, so best to be nice to any ants that you may come across!

Part of the Naked Scientists Question of the Week series – you can listen to the full version here.

Do roast potatoes give you cancer?

The UK Foods Standard Agency issued a health warning in 2017 about the chemical acrylamide – found in starchy foods such as bread and potatoes – saying that it may cause cancer. The warning coincides with the launch of a new health initiative called ‘go for gold’ which encourages us to only cook foods to a golden yellow, rather than brown or black, to help to reduce the amount of acrylamide. I spoke to Jasmine Just at Cancer Research UK…

  • Acrylamide is produced naturally by starchy foods when they are cooked at high temperatures for a long period of time, such as when baked, fried, roasted or toasted.
  • It is created by the Maillard reaction that occurs between sugars and amino acids in the presence of water, which is also responsible for the brown colour and roasted taste.
  •  A number of animal studies have found that acrylamide has the potential to damage our DNA which can lead to cancer, but the same process has yet to be established in humans.
  • The risk is described as ‘probable’ but is certainly much less than that from smoking, obesity and alcohol.
  • The advice from Cancer Research UK is to maintain a healthy balanced diet, follow the cooking recommendations for baked or roasted goods, and to not store potatoes in the fridge as this increases the potential for acrylamide to develop when they are cooked.

You can listen to the full interview for the Naked Scientists here.

Cocaine addiction leads to iron build-up in the brain

Cocaine used to be the drug of the rich and famous, but over recent years it has become cheaper and more readily available, and as a result more and more people are becoming addicted to this highly dangerous substance. A report last year from the UK Government Advisory Council found that 1 in 10 people between the ages of 16 and 59 had used the drug at some point. The current treatment for cocaine addicts is through therapy, but relapse rates remain high. Now a new study has linked cocaine addiction with a build up of iron in certain parts of the brain, and particularly areas known to control our inhibitions, although the team don’t yet know what the iron is doing there. I spoke with lead author Dr Karen Ersche…

  • Cocaine addiction leads to disruptions in the regulation of iron, with reduced levels in the blood and higher levels in the brain
  • Iron build-up in the brain is highly toxic and can be seen in other degenerative diseases such as dementia and Parkinson’s
  • Participants in the study had a brain scan which identified iron build-up in the area of the brain that controls inhibition
  • Possible explanations are that cocaine users have an appetite for fatty foods which hampers the absorption of iron, or that the cocaine weakens or destroys the blood-brain barrier causing iron to leak into the brain
  • The study also found a relationship between the amount of iron accumulation and the duration of cocaine use, but further work is needed to clarify its effect on brain cells
  • Understanding the relationship between cocaine addiction and iron regulation in the body could provide a new avenue for treatment in the future

You can listen to the full interview for the Naked Scientists here.

The World’s Smallest Knot

What do a clove hitch, a sheet bend and a sheepshank all have in common? They are of course, as any former scout will tell you, all knots. But I bet they couldn’t tie an 819 knot: at less than a millionth of a millimetre across, it’s the world’s smallest knot and has been tied by a team at the University of Manchester. They made the molecular tangle in a test tube using a sequence of carefully-controlled chemical reactions that used iron catalysts to bend and entwine short strings of carbon-rich molecules. I heard how from lead author David Leigh…

  • The knot is 192 atoms long with eight crossings and is the smallest, tightest knot ever tied.
  • The width of the knot is half a nanometre – less than one millionth of a millimetre or ten thousand times thinner than a human hair.
  • In mathematics, a knot describes a closed loop, which means that the knot here with its ends fused together, is still by definition a knot.
  • By viewing the positions of the atoms using X-ray crystallography, the knot can be seen to look like a four-leaf clover with extra strands wrapping around the outside of the leaves to generate the 8 crossings.
  • The knot is made using the technique of self-assembly where molecular strands are woven around metal ions, not too dissimilar to knitting.
  • The new technique used to make the knot could lead to a method of weaving molecular strands together to form stronger, lighter and more flexible materials.
  • In particular, Kevlar vest could be made much stronger by weaving the ‘rods’ of material together, rather than having them packed closely together like pencils in a pencil box, as is currently the case.

You can listen to the full interview for the Naked Scientists here.

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