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.

Music Taste Linked to Brain Type

How does the way you think influence the music you choose to listen to? Scientists at Cambridge University have developed a test that marries up a person’s personality traits including how empathic they are, and how systematically they think, with the tunes most likely to resonate with them. I went to see the lead researcher David Greenberg to discover what the test revealed about my own musical tastes…

David – The measure of empathy is called the empathy quotient and it’s a sixty-item measure that asks about how you interact in your daily life and your care for others, how you perceive emotion and react to emotion and thoughts of others. Another dimension is called systemising and systemising is the drive to construct, analyse and look at the rules that govern different aspects of the world.

Tom on the empathy quotient you scored a 56, and the average male scores around 30 so you were slightly above average on empathising. On systemising you scored very high – so you’re score is a 95 and the average male usually scores a 68.

Tom – Okay so that makes sense I guess – I do maths, I do see patterns in things and so this is sort of reflecting how I would have thought my brain worked.

David – It’s not too surprising because previous research has shown that males tend to score higher than females on systemising. And mathematicians score higher on systemising than for example students who are studying humanities.

Tom – And then once you’ve worked out how someone thinks, how did you then try to find out their musical preferences – do you say to them perhaps ‘here’s a list of band names who’d you like’?

David – No, so that’s been done previously where participants would just list how much they like a genre, but the problem with genres is that they’re so vast. If you take the rock genre in general, you have heavy metal, punk and you have bands like Metallica. But also in the rock genre you have Jeff Buckley or Jodie Mitchell and so there’s a vast difference. So we thought a more accurate way of doing it could be to just administer pieces of music to the participants: have them listen and then to indicate how much they liked each piece of music.

Tom – And so what did you find then? Once these participants have done this questionnaire you’ve worked out how they think – how did this affect their music choices?

David – What we found quite consistently over several studies was that empathisers in terms of the style of music that they liked, they were preferring music that was mellow and was from R&B, adult contemporary and soft rock genres. Whereas, systemisers were preferring music that was more intense and that was from the punk and heavy metal genres.

Tom – So what do I like? What did you find out about me?

David – You scored for example with mellow music or unpretentious styles which is from the folk genres or music that’s from classical or jazz, you scored average on those preference dimensions. But you scored the highest on intense music – so musical extracts that were from the punk, heavy metal and hard rock genres those were your favourites by far.

[MUSIC]

Tom – That was my favourite one that I listened to yesterday! I feel like I’ve been the perfect test student here! We’ve just been discussing exactly what type of music a systemiser should like and we’re just looking at my results here and I’ve nailed it to be honest!

And are there any applications for this beyond just figuring out which music people should and shouldn’t like?

David – A lot of research and there’s volumes of it has shown that music can be effective in music therapies. So, for example in terms of social skills or emotion recognition, we could use these results as a way of say teaching emotion recognition to children through music.

Tom – Based on my test results, play me the song that I should absolutely hate – I should leave the room I should dislike it that much!

[MUSIC]

…Yeah not liking that! That’s just so depressing I’m just not buying it.

David – But that’s the great thing about this study: there’s really no right or wrong answer. It’s just that people like different things and you can actually say that music is a mirror of the self in a way, it’s a reflective of who we are. And that our musical choices are a link or an expression of our mind, our personalities and the way we interact with the world.

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

Can a pill make you fitter?

These days it seems that we are always hearing about the latest ‘wonder pill’ that will help you to get fit – often with very little science to back it up. Well, this time things are a little different. Scientists at the Salk Institute in California have discovered a new pathway used by the body during exercise and are able to recreate its effects in mice by simply giving them a pill. The mice were able to run for a much longer period of time and gained less weight! I spoke to senior researcher Weiwei Fan to find out how it all works…

  • The process involves a protein called PPL-delta which during exercise turns up the genes that burn fat and turns down the genes that burn sugar.
  • Mice that were given a chemical to activate the PPL-delta protein over an 8-week period could run for about 270 minutes, whereas mice that were not on the drug could only run for about 160 minutes.
  • The activation of the protein not only increases endurance, but by burning fat instead of glucose it can also result in weight loss, making it a possible treatment for type 2 diabetes, obesity and fatty liver disease.
  • On a high-fat diet, the mice with the drug gained 50% less weight than those without, with the weight loss occurring almost entirely in fat rather than muscle.
  • The ultimate goal is to test the findings in humans once the current negative side effects of the drug are eliminated.

 

 

 

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

World Cup 2018: The Perfect Penalty Kick

 

The 2018 World Cup in Russia kicks off today and so I bring you a special double-edition of Throwback Thursday looking at the science behind the perfect penalty kick… Fingers crossed the England players listen/read my website and we don’t lose to Germany in a penalty shootout (though let’s be honest we probably will).

Live interview with BBC Radio Cambridgeshire looking at the ‘unsaveable zone’ and the best way to mentally prepare for a penalty.

 

And if that wasn’t enough, here’s a full description of the ‘Penalty Kick Equation’…

For all of the footballers out there who have missed penalties recently, I thought I would explain the idea of the science behind the perfect penalty a little further, and in particular the maths equation that describes the movement of the ball. On the radio of course I couldn’t really describe the equation, so here it is:

Screen Shot 2017-06-05 at 10.09.22

If you’re not a mathematician it might look a little scary, but it’s really not too bad. The term on the left-hand side, D, gives the movement of the ball in the direction perpendicular to the direction in which the ball is kicked. In other words, how much the ball curves either left or right. This is what we want to know when a player is lining up to take a penalty, because knowing how much the ball will curl will tell us where it will end up. To work this out we need to input the variables of the system – basically use the information that we have about the kick and input it into the equation to get the result. It’s like one of those ‘function machines’ that teachers used to talk about at school: I input 4 into the ‘machine’ and it gives me 8, then I put in 5 and I get 10, what will happen if I input 6? The equation above works on the same idea, except we input a few different things and the result tells us how much the ball will curl.

So, what are the inputs on the right-hand side? The symbol p just represents the number 3.141… and it appears in the equation because footballs are round. Anytime we are using circles or spheres in maths, you can bet that p will pop up in the equations – it’s sort of its job. The ball itself is represented by R which gives the ball’s radius, i.e. how big it is, and the ball’s mass is given by m. We might expect that for a smaller ball or a lighter ball the amount it will curl will be different, so it is good to see these things are represented in the equation – sort of a sanity test if you will. The air that the ball is moving through is also important and this is represented by r, which is the density of the air. It will be pretty constant unless it’s a particularly humid or dry day.

Now, what else do you think might have an effect on how much the ball will curl? Well, surely it will depend on how hard the ball is kicked… correct. The velocity of the ball is given by v. The distance the ball has moved in the direction it is kicked is given by x, which is important as the ball will curl more over a long distance than it will if kicked only 1 metre from the goal. For a penalty this distance will be fixed at 12 yards or about 11m. The final variable is w – the angular velocity of the ball. This represents how fast the ball is spinning and you can think of it as how much ‘whip’ has been put on the ball by the player. Cristiano Ronaldo loves to hit them straight so w will be small, but for Beckham – aka the king of curl- w will be much larger. He did of course smash that one straight down the middle versus Argentina in 2002 though…

So there you have it. The maths equation that tells you how much a football will curl based on how hard you hit it and how much ‘whip’ you give it. Footballers often get a bad reputation for perhaps not being the brightest bunch, but every time they step up to take a free kick or a penalty they are pretty much doing this calculation in their head. Maybe they’re not quite so bad after all…

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