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27th Jan 2008
Flu and Viruses
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In this week's not-to-be-sniffed-at infectious episode of the naked scientists, we find out the facts of flu, including how the virus hijacks your cells, how new strains of the virus emerge to trigger epidemics and pandemics, and how scientists can combat the threat with vaccines. Also under the microscope is a new technique to identify viruses within just 2 hours, providing patients with a fast track to the right treatment! Also, how bone marrow transplants can overcome organ rejection, how to stop a terrorist with a mobile phone, and the new material 30 times blacker than our current blackest black! Plus, in kitchen science, we'll be pouring cold water on claims of centrifugal force...
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Kitchen Science
Have a bucket full of water upside down over your head, and stay dry!
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Question of the Week
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Could a plane take off on a 'treadmill' runway?
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How funny - thanks for telling us! Chris...
- chris - 31st Jan 08
FYI: http://www.edcp.org/influenza/Influenza_serv.html if you want to know how flu is going on this side of the Atlantic. I keep tabs on how things ar...
- RenRen - 1st Feb 08
Thank you, we're very grateful for your feedback. And if you'd like to write an article for us about what you do, that would be wonderful! - chris - 1st Feb 08
I would be honored to write something up. There are two options, however... I could write as an epidemiologist and just talk about how we go about inv...
- RenRen - 1st Feb 08
Whole Thread | Post Reply
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Questions

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Fluorescent lights are already efficient when they’re running but I’ve heard that it takes a lot of energy to turn a fluorescent light tube on. So is it more efficient to turn off a fluorescent tube immediately when you’ve finished using it or is it better to leave it on and then wait until you’re more likely to not use it again for a while?
This question was first asked in last week's show.
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Last week Derek in Belgium asked a question about fluorescent lights, but we didn’t know what that period of time was to make switching off a light more efficient than leaving it on.
I have to say a very big thank you to Shia Frederick and also to Kurt Challetts who both found me the answer and they’ve sent me some references. Based on experimentation they have concluded that – these references they’ve sent me – a fluorescent light uses as much energy getting started as it des to run for 23.3 seconds. In other words, that is a bit of a myth about leaving it on for very long. If you’re going to be in the room and gone for less than 23.3 seconds there’s no point it on, basically. You might as well turn it off because it uses not very much more energy. To put that in comparison, an LED has to run for 1.28 seconds before it uses as much energy. The good old-fashioned incandescent lamp: 0.36 seconds before it’s used as much energy it does running as it does to turn it on.
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I recently bought some tiny magnets from a hardware store to stick things up on my wall. I bought these magnets called rare earth magnets. They’re so strong that now I can’t unstick them from each other. It’s amazing, can you tell me how these tiny magnets that’re about 1.5cm in diameter, different from other magnets that don’t have the same kind of power?
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On a fundamental minute scale iron, nickel and cobalt atoms have more electrons orbiting in one direction than the other. This means they produce little, tiny currents like electromagnets. With ferromagnetic things like iron, nickel and cobalt – these tend to like lining up into areas. Normally if you just take these areas, the north poles of these little areas will attract south poles of other little areas. They’ll all wind up going into circles and ovals in magnetism. If you put them in a strong magnetic field they’ll all line up. Normally with iron, if you take the magnetic field off, most of them will realign and then all the rest more randomly.
They get all jiggled up and end up pointing in random directions again. With very strong magnets, like rare earth magnets, the structure of the alloy tends to make it very hard to change the direction of the magnetic field. This means that more of them stay lines up, and you get a stronger magnet.
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My wife and I are expecting our first child and we’ve been using a Doppler machine to listen to the baby’s heartbeat. It’s very fast, at least 150bpm whereas ours is about 70. Why is this? Does an elephant have a very slow heartbeat and does it take longer for the blood to circulate in bigger animals, for example?
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You’re on the right lines there, George. The reason is that if you think of a heart as almost a sphere and the volume of a sphere is given by the mathematical formula 4/3πr3. That’s the volume of blood that a heart could hold. You could work out how much output’s coming out of your heart by multiplying the number of times per minute the heart beats (the heart rate) by what’s called the stroke volume (how much blood the heart squeezes out with every beat). Given that a heart that’s small, instead of it just decreasing its volume by a small amount when you shrink the heart a bit it will actually decrease the volume of blood proportionately by the radius cubed. For every shrinkage of the heart, if the heart gets smaller and smaller – in fact there’s a very big decrease in the amount of volume it can pump. You can compensate for the reduced volume by increasing the rate at which you pump. If you have a smaller heart you have to make it go faster. A mouse’s heart, for instance, can be pumping at two-four hundred times a minute whereas a big whale could have a heartbeat of say 20 or 10 times a minute but it has got a heart which is the same size as a Volkswagen beetle. That’s why.
On a related note, if you’ve got a very big heart it’s going to be almost impossible to empty that very, very quickly. It’ll be impossible to empty a whale’s heart which is several feet across 400 times per second. You just couldn’t shift the blood quick enough. It's likely that the dynamics of muscle contraction wouldn’t be able to occur fast enough to make the muscle get shorter quickly enough en masse to move that amount of blood at that speed. It is a phenomenal thing to have achieved.
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I’ve been in contact with someone who’s had the flu quite badly but I didn’t catch it. Why would that be?
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We put this question to Dr John Wood:
Well, I don’t know the particular circumstances. It’s possible, I hope, that maybe he had a vaccine but maybe not. He could have been exposed to flu in the past which gave him some immunity. Maybe he didn’t know he’d been exposed to flu in the past. It may have been a kind of sub-clinical infection he didn’t notice. I expect he had some kind of immunity.
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Since viruses aren’t technically living organisms, where did they come from and how were they formed how have they evolved?
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We put this question to Cambridge University Researcher Ed Hutchinson:
In the case of flu you’ve got the fact that flu will spread from organism to organism so although we’re worried particularly about a human virus or a virus of livestock as well it actually starts of as a virus in waterfowl. Things like ducks where it’s not really a pathogen at all. It just lives in there and gets along with them. That doesn’t really tell you where a virus has come from. We know that they can spread from organism to organism. In the first place viruses probably evolve as just bits of the genetic sequence which just get out of hand and start copying themselves, moving to places they shouldn’t and acquiring more and more abilities along the way. There are quite a few examples of this where thing start jumping around inside genomes eventually will get the ability to jump from cell to cell as well.
Chris: In the answer to what came first, chicken or the egg, the virus cell situation has to be the cell came first, the virus came later.
Ed: Remember, the defining feature of the virus is that it’s absolutely dependent on taking over a cell to work. Without a cell the virus isn’t going to do anything at all.
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If you suffer from coldsores, can you pass on the virus even when you don't have a coldsore showing?
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We put this question to Cambridge University researcher Ed Hutchinson:
I’m afraid, unfortunately the answer is sometimes, yes you can. Cold sores belong to a family of viruses called herpes viruses. These don’t just include the famous sort of herpes we’ve all heard of but a whole range of viruses. These viruses have a nasty trick of causing visible infection then hiding and coming back at various points in your life. It’s called latency. If the cold sore’s happening it’s hiding in some nerves in the side of your head and they’re coming back into you’re mouth on a regular basis. Sometimes this is going to cause a visible cold sore and sometimes it’s going to cause something you can’t see but it’s still going to be shedding infectious virus into your saliva. I’m afraid it’s always a risk.
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| Flu and Viruses - More about this podcastIf you've spent this winter curled up in bed, running a high temperature and sipping hot lemon, then you've probably had a brush with 'flu. This week on the Naked Scientists, we're looking into the science of flu, viruses and the vaccines that could keep us out of bed!
Who's Virus it it Anyway?
When your feeling achy or coughing hysterically, it can be frustrating when the doctor sends you for various time-consuming tests to find out what's wrong with you, and in many cases you often feel better by the time they find out what was wrong!
But now a new technique in use at Addenbrookes hospital in Cambridge is revolutionising diagnosis of flu and the common cold. Real-time PCR is a new sampling procedure that can tell you all the bugs you've got in your system within 2 hours!
Meera speaks to Dr Martin Curran about how this analysis works and the benefits associated with it.
If the genes don't fit...
Every so often, new strains of the influenza virus appear and cause devastating pandemics, which can kill millions of people. One way for these new strains to appear is when two different viruses, used to growing in different host species, infect a cell at the same time. The viruses produced from this cell will get some genes from one parent virus, and some from the other.
Influenza can do this as its genes are not all on a single strand but are divided between eight, physically separate, segments. These segments are a bit like chromosomes, and as well as allowing the virus to swap genes they also cause it problems. A new virus must include at least one copy of each of the eight segments, from whatever source, otherwise it will be missing genes. We know that influenza has evolved a mechanism to make sure that all eight segments are included when a new virus is put together, but we don’t know what it is or how it works.
Cambridge University researcher Ed Hutchinson is using a range of genetic techniques to identify the bits of segments involved in making sure influenza includes all its genes – something we need to know both to understand this deadly virus, and to design vaccines against it.
Virus Vaccines
Here in the UK, once you're collecting your pension you're also encouraged to collect a 'flu vaccination every year. But how are these vaccines made? If viruses are constantly mutating, how can we tell if a vaccine is any good? Will a winter flu jab keep you safe from other viruses, even bird flu?
Dr John Wood, Principal Scientist in the Division of Virology at the National Institute for Biological Standards and Control (NIBSC) in the UK, will be coming into the studio to tell us about his work. Dr Wood sits on the World Health Organisation advisory panel on influenza vaccine development, and is working on vaccinations that will protect across a broad range of viruses, including H5N1 bird flu.
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