Podcast: Best of 2023, sustainable flight fuel, and better bones

December podcast


In this edition: 2023 in review, the first transatlantic flight using 100% sustainable aviation fuel, and improving bone quality.

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News: Best of 2023 – We hear about some of the best quantum breakthroughs and how science has met art at Imperial in 2023, as told by our science communication interns.

Sustainable aviation fuel flights – We talk to Dr Marc Stettler and Dr Roger Teoh, two of the researchers involved in the world’s first transatlantic flight using 100% sustainable aviation fuel, made primarily of waste fats and cooking oil. The Imperial team helped assess the potential impact of such flights, including the formation of contrails.

Bone up on bones – We catch up with the Bone Up podcast, which discusses everything about bones: how we make them, why we break them, and what we still don’t fully understand about them. In this clip, we hear about how improving diet and lifestyle can impact the quality of bones and help prevent fractures in the most vulnerable people.


(20 December 2023)


Gareth Mitchell:               Hello everyone. I'm Gareth Mitchell. Today, have we all inched a bit closer to sustainable aviation? One researcher thinks that we have. He was on board the other day for a transatlantic flight on a 787, running 100% on sustainable aviation fuel.

Mark Stettler:                    There is a demand for sustainable aviation fuel. There's no technical reason why it can't be used. This is one important small step along the way to making aviation more sustainable.

Gareth Mitchell:               But there are worries over what sustainable really means. Stay with us for an insightful chat and in our pick of the pods this month. A remarkable finding about how good old cheese and yogurt seem to improve bone health for elderly people in care homes.

Gareth Mitchell:               All right, well, let's jump in with our usual news update. When I say our usual news update, actually it's a bit different this time here goes.

Sharvani:                            Hi everyone, I'm Sharvani. I'm a science communication master student at Imperial College London. And I'm also the digital intern for the communications division at Imperial, where I'm helping create content for Imperial's various social media channels like YouTube, Instagram, Facebook. And I'm working alongside my supervisor who's in the communications team.

Alex:                                    I'm Alex. I am also on the masters of Science Communication at Imperial, and I'm working as a news intern for the communications division, which includes writing features and news articles as I'm sure you'll hear later in this podcast.

Helena:                               Hi, I'm Helena and I'm also doing my masters in Science communication here at Imperial. I am part one of the news interns for Imperial, where I am writing stories about all the exciting things that are happening at Imperial.

Gareth Mitchell:               Great to meet you folks. Well, I'm saying that as if I've just met you and as a kind of treat for the end of the year, we'd like to do something a bit special as we're coming up to Christmas, we're just going to run round some of the listicles that you've been writing. It sounds very seasonal, doesn't it? It's like icicles, listicles. I don't know if that's where it came from.

                                             Why don't we get you, Sharvani, to introduce the two sets of listicles that we're going to be talking about because they're on different subjects. So there are three of you, two subjects. So you just summed them both up for us if you will.

Sharvani:                            Yep. It's been a year of breakthroughs for Imperial, and Imperial has pushed a lot of boundaries this year in terms of research as well as how to communicate that research. Quantum's been the buzzword in science for a long time now, and Imperial's had numerous quantum breakthroughs ranging from wave function experiments to satellite free navigation systems. And Alex is going to tell us a bit about her favorite quantum breakthroughs from Imperial.

Gareth Mitchell:               Oh, all right. A quantum, fascinating and there's a lot of it about, you'd expect so at Imperial, wouldn't you, Alex?

Alex:                                    Definitely, yeah.

Gareth Mitchell:               So your brief has been to write a list of five quantum things that have happened at Imperial then.

Alex:                                    Well, our brief was we basically just got given this lump of the most popular news stories at Imperial and we got to pick out our few favorite ones and I gravitated towards the quantum physics ones. Give myself a little challenge.

Gareth Mitchell:               What has stuck with you for the year?

Alex:                                    Well, when you were talking about the icicles, listicles, the one that stood out to me in my little listicles was Imperial's magnetometer, the mission titled it Juice, which stands for Jupiter Icy Moons Explorer. Then it's going to try and measure the magnetic field of Jupiter. So what Imperial has been doing in this development is actually testing it for the extreme conditions that it'll be facing in space. For example, going in with intense radiation and zero gravity and extreme temperatures. And it's managed to actually pass all those tests so it's ready for launch.

Gareth Mitchell:               And at the heart of it, quantum technology, there'll be more.

Alex:                                    Yeah, so much more. I mean, there's actually been the launch of the new department called Quest, which is a Center of Quantum Engineering, Science and Technology at Imperial. And that will be the center that's focused on all quantum research and that will include different sensors, different machinery, lots of space stuff, which you'll be hearing more.

Gareth Mitchell:               You're so lucky getting to write about quantum. Sharvani, back to you then. What else has been catching your eye in these Christmas listicles?

Sharvani:                            Yeah, so I think within science there's this trend to just have lots of interdisciplinary research, bringing together researches from so many disciplines and producing all of this cool science that Alex has kind of just spoken about. But what you probably wouldn't expect from Imperial is that there's lots of overlaps between science and other disciplines such as art. So lots of interdisciplinary work, even outside science.

                                             Imperial has pushed a lot of boundaries this year in terms of communicating science and making the people aware of all this wonderful research that's going on within science at Imperial. So one of the major breakthroughs for Imperial this year has been combining science and art to communicate to the wider public and to engage people through lots of sensory experiences and memorable things that they can connect to the science with.

                                             So now Helena is going to be telling us a bit about this intersection between science and art through which Imperial's using to communicate science to the public.

Gareth Mitchell:               Wow. So again, Helena, there must've been a whole lot of stuff to pick through to give us those top five or top 10 whatever, great highlights from the art and the sensory world, and of course all the science, technology, engineering, business, mathematics and everything else that goes on here.

Helena:                               Yeah, definitely. All right. There's so many interesting ways Imperial has used arts to communicate science this year. One I found really interesting was the Future Fridge, and I actually got to sample this at the Imperial Lates recently, which was about the future of food. That's a collaboration between a design agency and a community center and Imperial researchers. And it's actually an interactive fridge, but it's not your typical fridge because there's no actual food you can eat inside it. There's familiar and not so familiar types of food. There's milk, little cartons and milk, obviously you can't drink them. And then there's also chicken nuggets made from insect protein.

                                             So the purpose of the fridge is for us to understand how trends in food are going to evolve over the next few years, and for Imperial researchers to understand how attitudes in food production might change. Obviously we know that climate change and different things are impacting food production and farmers and designers are trying to come up with new ways to produce food. So this fridge is a great way for researchers to understand, first of all how we think food is going to change in the next few years, and second, what are people's attitudes to how these foods are going to change. And they can kind of use this public engagement to help shape communications of when these new foods do come out to make sure they're kind of addressing the public's concerns. So like I said, I got to try playing out with the fridge, at the Imperial Lates, and it was a really fun experience. So yeah.

Gareth Mitchell:               Sure, yeah. It had these chicken nuggets, but they weren't chicken. They were made out of insect protein. So did you get to try any of those?

Helena:                               No, no. The thing about the fridge, it's just kind of packages and it says, chicken nuggets made from insect protein. So there's not actually any food in there, I think because it's not cold, so it'll be a bit of a health hazard.

Gareth Mitchell:               Oh, yeah. I'm glad you pointed this out.

Helena:                               More of a cardboard fridge but it was really cool to kind of imagine and think about, "Oh, I wonder how chicken nuggets would taste if they were made from insects. Would they taste nicer? Would they taste worse?” That kind of thing.

Gareth Mitchell:               I got it. But nonetheless, you're just very much presented with this fridge of the future and it's a good conversation starter as it's doing now as well. Excellent. So all of you, your news interns. So how's that been going then? There's a whole lot of news coming out of this place. I bet you've been busy, haven't you?

Sharvani:                            Yeah, it's been really good. So I think one of my personal interests with this internship is just making human stories of researchers involved in science more accessible to the public. And there's just so much cool science going on, but even cooler than that to me are just the scientists and the people working behind the scenes to produce this science. So a project that I'm going to be starting early next year is just going into various labs and interviewing scientists and getting them to talk about their daily lives and what they're interested in, how they got into research and kind of how their research connects to wider society beyond just explaining scientific concepts to people. So that's the project I'm quite excited to work on next year.

Gareth Mitchell:               Yeah. What about you then, Alex? Any thoughts about next year already?

Alex:                                    Yes, definitely. One amazing thing that I got to do this year was conduct my first journalistic style interview, but one of the pieces that I did, and I was very, very nervous about it because these were incredible researchers. But then once I sat down with them and they gave me a lab tour and I took some photos and wrote it all up, I just got this thrill and I'm definitely going to try and hassle some more researchers next semester and get them to do some interviews with me.

Gareth Mitchell:               Yeah, you get some great access doing this job. So a very good way of legitimately finding out all about the gossip around the college.

Alex:                                    Exactly.

Gareth Mitchell:               Must say. So Helena, in my case, I just do this, I'm pathologically nosy, so is that you as well then nosing around the campus finding these amazing researchers?

Helena:                               Yeah, I was going to say, when you talked about finding out all the gossip, that's what I really enjoyed doing the internship. What I really enjoy is kind of hearing about what's kind of happening at Imperial. I don't know if you heard but there was a Virgin Atlantic satellite that went off and we were talking.

Gareth Mitchell:               That's the next item in the podcast. Yes.

Helena:                               So we were talking about that about a few weeks before it actually happened. It was really cool seeing social media from other places like the BBC and I was like, "Oh wow, there was someone from Imperial who was on their flight." And we talked about that in the communications team. So that was a really, really fun experience getting to hear about the news agenda.

Gareth Mitchell:               So gossip jokes aside. Yeah, let's face it, this is a big high profile University. A lot of news comes out of here and what you're doing and as part of, it's such an important function. So keep at it and thanks for bringing us those listicles. I've learned a lot, fridges and quantum, my goodness. All right, thanks a lot folks and have a lovely Christmas.

Helena:                               Thank You. Thank you.

Gareth Mitchell:               There they are. The news interns that's Alex, Sharvani and Helena. All right, so last week at Cop 28 in Dubai, nations agreed to transition away, careful wording there, transition away from fossil fuels and the move adds further salience really to the rather special flight at the end of November of a Virgin Atlantic Boeing 787 from London's Heathrow Airport to New York.

                                             The aircraft was powered by 100% sustainable aviation fuel or SAF. Now one of the research priorities in SAF is investigating how the fuel affects contrails. You know those white trails that we sometimes see at high altitude when we look up at planes? Though contrails might look quite benign, they actually have significant warming effects. So will sustainable aviation fuels help to reduce those effects?

                                             And then of course there are questions about sourcing enough SAF to support the global aviation fleet. These are just some of the research questions behind the project that led to that 787 taking off from Heathrow a few weeks ago. Well let's hear more now from a couple of the researchers involved. First, Dr. Mark Stetler, who's at Imperial's Department of Civil and Environmental Engineering. So Mark, welcome to the podcast and you were on that flight, weren't you? So how was it?

Mark Stettler:                    So in some ways it was unlike any other flight I've been on, but in other ways, and in the ways you'd really care about, it was just like any other flight. So we didn't experience any technical issues. There was just a smooth flight. There was no difference from the passenger's perspective.

Gareth Mitchell:               In fact, we have a little bit of video that you took. This is just a bit of video from the cabin and we can just hear just basically how normal it sounded. Here it goes. But of course this was an unusual flight. It wasn't a scheduled passenger flight and the culmination of a big project researching sustainable aviation fuel. So just tell me about this project.

Mark Stettler:                    Yeah, so the project was in response to a government call to operate a flight from the UK to the US on 100% sustainable aviation fuel and Virgin Atlantic pulled together a consortium of partners, which included Boeing, Rolls Royce, fuel supply partners, Byron and BP and the University of Sheffield and Imperial. And our role predominantly was to work on quantifying the non CO2 climate effects of sustainable aviation fuel. It's been a huge effort on the technical side to get through all of the regulatory approval hoops, just to get this through.

Gareth Mitchell:               We'd better talk about the fuel itself. So what is this non kerosene based fuel?

Mark Stettler:                    In almost all respects, it is identical to fossil derived jet fuel. So it operates in the same way. There's no required modifications to the aircraft or to the engine. It's often referred to as a drop-in fuel, which means that it can just be used in substitution for fossil derived jet fuel.

                                             The fuel that was used on this flight was predominantly from waste fats and cooking oil that were then turned into the molecules that make up jet fuel. Ultimately when you burn the fuel, the same amount of carbon and the same amount of CO2 is released, but you've in theory, absorbed carbon in the production of that fuel. In this case, it was because those waste oils didn't degrade and it's all to do with that lifecycle.

Gareth Mitchell:               Right, okay. So what is it? Partly because the argument is that those are waste oils anyway. They've come from the likes of presumably palm oil or coconut oil or what have you. So as this is being burnt, then other plantations or coconut or, insert your equivalence if you need to, are being planted and then that would be the mitigation for the carbon that's emitted during the flight.

Mark Stettler:                    Well, in this case there was a specific requirement not to include any palm oil because that has been a controversial issue and there has been controversy about taking what would be a source of food and turning that into a fuel that's used for transport mode. In fact, when we go to fill up at the petrol station, 10% of the petrol comes from a bio-derived pathway. In some cases sustainable aviation fuel could reduce the overall lifecycle of CO2 by somewhere up to 80 to 90%. And that's where you get the CO2 benefit. It's over the lifecycle of the fuel, even though the carbon dioxide emitted by the engine is exactly the same.

Gareth Mitchell:               All right, and that's something that's important to get across. Especially as we sit here, we just got to the end of COP 28 and people listening to this thinking we've just had COP and these guys are talking about a flight that admits as much carbon as a regular flight. But you're talking about the lifecycle. And you are addressing this concern that some people say when you're talking about, let's just say plant oils, that this isn't about displacing crops that would otherwise be used for food and creating a whole other sustainability issue then. That's been thought out as part of this project, has it?

Mark Stettler:                    It has, yeah. So as part of this project, but also as part of the wider industry efforts to increase the amount of sustainable aviation fuel that's used.

Gareth Mitchell:               Okay, well let's bring in your colleague here also on the project. Dr Roger Teoh, he's with Imperial's Departments of Civil and Environmental Engineering as well. So Roger, you're very much on the data side of things here. You weren't on the flight, but nonetheless, you were supporting from the ground. So how were you doing that?

Roger Teoh:                       Yes, essentially there are three different tasks that we need to do on the ground. We need to simulate the fuel consumption and the particle emissions that will be emitted from the Boeing 787. We then feed it into a control model to simulate, to see whether or not persistence contrails form and how does it evolve over its lifetime. Contrails are line-shaped clouds that form behind an aircraft when the air is supersaturated with respect to ice.

                                             So when under favorable atmospheric conditions, the water vapor would condense onto this particle, the particles that are emitted by the aircraft and those water droplets then freeze to form control ice crystals. The third task is to compare the simulated contrail outputs with the satellite observations to somewhat validate our model to see whether our predictions are correct or not.

Gareth Mitchell:               So you are looking at the contrails. Why are the contrails so interesting in this research?

Roger Teoh:                       We see that on average the annual climate effects from contrails is about two to three times more than the cumulative CO2 emissions that has been emitted since the 1940s.

Gareth Mitchell:               How does a control have such big effects?

Roger Teoh:                       Based on our earlier publications, we see that 2% of flights are responsible for 80% of the contrail controversy. The reason for that is because for these flights, these contrails can persist for a long period of time. So while they stay in that atmosphere, they can spread horizontally to a very large area up to hundreds of kilometers. Because it covers such a large area, therefore it can trap more heat and remit it back to the surface of the earth, causing a warming effect.

Gareth Mitchell:               Especially when you aggregate it up amongst all the global air fleet. That aggregates into a big global warming like greenhouse effect trapping heat in the atmosphere.

Roger Teoh:                       That's right.

Gareth Mitchell:               Now the flight that we're talking about, the atmospheric conditions meant that there weren't any contrails on the day to measure, but data from elsewhere says that sustainable aviation fuel, SAF, does reduce contrails. We also know there's not enough of this sustainable fuel around and you are bringing these two pieces of evidence together, aren't you?

Roger Teoh:                       Yes, that's a very important point. So if you can target and you can identify the flights with the most strongly warming contrails and target the scarce supply of SAF to these flights, there could be a multiplier in terms of the environmental benefits of SAF, not just on the CO2 effects, CO2 and non CO2.

Gareth Mitchell:               Right. So a targeted effect then. Mark, is that the full solution here?

Mark Stettler:                    So I think what Roger said there is really important while we're scaling up the supply of SAF. When we consider the amount of supply that's available today, it's very low. What this flight has done has shown that technically there's no barriers. It also has shown that there is industry demand. We are also seeing very strong policy indicators in the EU, in the UK and to some extent in the US. Where there is governments that are putting in place mandates on the amount of SAF that needs to be used as jet fuel.

                                             So for instance, in the EU, in the UK and in the US, there are policy measures now which are targeted at increasing the proportion of sustainable aviation fuel used in the fuel that's supplied in those countries and regions. There's a very clear policy incentive to ramp up the amount of sustainable aviation fuel that's being used by the industry.

Gareth Mitchell:               And of course there will be those saying, well rather than trying to tinker with the providence of the fuel on aircraft, we should just have less aviation. That's really the only way we're going to make a significant difference to tackle climate change. Is there a case for that argument?

Mark Stettler:                    Yes, I think there is an argument. But really that has to be based around what is the target? Where do we want to be able to get to? We acknowledge that all sectors are going to have to decarbonize, how do we manage that and also not completely get rid of the benefits that come with being able to share cultures and experiences and travel across the world.

Gareth Mitchell:               Now Mark, this was a very high profile flight and you were one of the key people involved. So how is it for you?

Mark Stettler:                    Yeah, so I can see the huge amount of effort that went into the project to demonstrate scale, to demonstrate that there is a demand for sustainable aviation fuel. It is much more expensive than fossil derived jet fuel. But what this shows is there's no technical reason why it can't be used. This is one important small step along the way to making aviation more sustainable.

Gareth Mitchell:               All right Mark, we'll leave it there. Thank you very much. That's Dr. Mark Stetler from the Department of Civil and Environmental Engineering. And thank you also to you Dr Roger Teoh.

                                             All right now for our monthly check-in with just one of the many podcasts from around Imperial College. This month, it's time to Bone Up. Before we hear a clip, let's meet the hosts.

David Armstrong:             Hello, my name is David Armstrong. I'm a doctor who specializes in osteoporosis. And as you might guess from my accent, I work in Northern Ireland.

Richie Abel:                        Hi, I'm Richie Abel, a scientist working at Imperial College in the faculty of medicine. And together we are the co-host of our podcast Bone Up.

David Armstrong:             In every episode we discuss bones. We have interviews with researchers. We've had some interviews with patients. I think we enjoy ourselves as well, Richie. Just bouncing ideas off one another and finding out all about bones, about as we say in our introduction, how we make them. Why we break them. And I think we've decided that we still don't fully understand them.

Richie Abel:                        It's really good fun recording the podcast. Initially when we started the podcast we really thought we were aiming at kind of a public audience, a lay audience, but we realized over time that actually a lot of professional people listen to the podcast as well. And that's really great because I hope that what we're doing is we're linking up the professional researchers and the professional clinicians. So they can start to share information and knowledge. And ultimately I hope for the public we're going to be able to empower people living with bone disease and their families.

David Armstrong:             I think empowerment is key to what we're doing. I had a patient at the clinic just this morning who was telling me that she listened to the podcast. She said while she didn't understand everything that was said, she was very excited to hear about new treatments. She was very excited to hear about people all over the world are doing research and actually was excited to hear both practicing doctors and what she described as high level scientists, that's you Richie, working together, talking about things and sort of enjoyed listening to us bouncing ideas off one another.

                                             We've got through 19 episodes now and we haven't been closed down yet. We've still got plenty of new ideas. You were telling me, Richie, we've been streamed over 20,000 times now in 40 different countries. Although we don't do it for the baubles, we were awarded the Neil McKenzie Public Engagement Award in 2022 by the Bone Research Society here in the UK.

Richie Abel:                        It was really nice to get a bit of recognition for the work. Anyway, I think you're going to hear a clip of the podcast now so you can make up your own minds.

David Armstrong:             One of the conferences I was at was the European Geriatric Medicine meeting in London. I'm not a geriatrician, I'm a rheumatologist, but we're all friends together when we're talking about osteoporosis and bone health. And while I was there I was asked to chair a symposium with a scientist from Melbourne in Australia called Dr Sandra Luliano. And Sandra produced some fascinating work really on that area, on lifestyle and diet and how it can impact on bone health and fracture risk.

                                             And Sandra picked up on a group of patients who were particularly vulnerable to fracture and those were patients living in nursing homes or residential homes, in the longer term. She noticed that their calcium intake and their protein intake was quite poor and she sought to see how she could address that. Not with artificial supplements, but just with food, then indeed with food in the terms of dairy produce. And as an interesting, Richie, at the complete other end of the spectrum, you're working on the nano scale with bones and you're talking about how diet and lifestyle can actually impact upon quality of bone as well.

Richie Abel:                        I think that's important. If we do studies at the population level, epidemiological studies. Looking at associations between say, diet and disease or fracture, or even if we do interventions where we test whether or not diet might be able to reduce falls and reduce hip fractures, 50% is amazing. I'm really excited to talk to Dr Luliano today.

Sandra Luliano:                 What we did is we observed in residential aged care, which is the care homes, that the intake of protein and calcium foods was declining. So we know that their intake of foods that have calcium, i.e., the dairy foods and also foods with protein. So the foods in the meat food group and the dairy food group were declining. And so you've got a group that are deficient in these two nutrients. So we went about looking at if we improve the intake of dairy foods in this group, so they improved their protein and calcium intake, would it reduce falls and fractures? This trial involved 60 aged care facilities or aged care homes across metropolitan Melbourne and regional Victoria. What we try to do is get a really big variety of homes. So homes that were small, medium and large not-for-profit, for-profit, singularly owned. So we really wanted a good cross-section of facilities and of the 60 facilities, they were randomized.

                                             So we randomized by facility, not by person. So by facility we randomized 30 of the facilities to improve the dairy content of their menu. And the other 30 facilities went about their usual menu as it stands, what they're providing. So for the intervention facilities, we had a dietician that was really good with food service, work directly with the food service team. So the importance here of the trial is not saying this is how you have to do it. It's about saying' "How do you cook? What do your residents like to eat and how can we accommodate that by improving the dairy content?" Now by dairy, we need to be quite specific here. In Australia, dairy is milk, yogurt and cheese. All we did was improve the dairy content of the menu. So we made sure that there were lots of opportunities throughout the entire menu. So we are looking breakfast, lunch, dinner, all the snacks in between, that there was the provision of dairy food, milk, yogurt, cheese.

David Armstrong:             So tell us about the outcomes then because I think that's the really exciting thing. You actually managed to reduce the number of fractures in the care homes in which you had the intervention. Is that right?

Sandra Luliano:                 Yeah, we did. Look, so what we observed is that in the facilities or the aged care homes that received the additional dairy food, so just to give you an idea, they went from two servings to three and a half servings. So we're still within recommended levels. We observed a 33% reduction in all fractures and a 46% reduction in hip fractures.

                                             So when you look at that number, you go, "Oh my god, this is massive." But what we observed is all but one of our fractures resulted from a fall and we observed an 11% reduction in falls. So with the falls, we look at it and go 11%, not much. But two thirds of residents fall. And so over the period of time we observed 23,000 falls. So an 11% reduction now becomes a quite significant number of falls that have been reduced.

David Armstrong:             So that almost asks one of the other questions about why this might've been the case. So you were reducing falls, which you feel was at least partly a big contributor to the reduced number of fractures.

Sandra Luliano:                 Yeah, look, I think so. So there's two parts to it. One is that we know calcium has a very modest effect on bone remodeling. So it's not like the bisphosphonates. It's not like the medications. But those medications can only be used in people that have either osteoporosis or have had a prior fracture or have a risk factor. We can't just give these drugs to everybody that is in a care home. What we needed was an intervention that was safe but effective.

                                             So you can imagine across the entire care home, all we did was increase the dairy content of the menu. So in a sense, if you imagine the beautiful, your usual bell shaped curve. So you've got the high risk people with osteoporosis at one end. You've got the low risk people that have just amazing bones at the other end. And you've got the bulk of people in the middle that are at moderate risk. We shifted that entire bowel curve to a lower level of risk. So the majority of people are at moderate risk but they contribute the greatest number of fractures. So we just shifted that entire group to a lower level of risk.

Gareth Mitchell:               Amazing results. Dr Sandra Luliano of the University of Melbourne, talking to Richie and Davey on the Bone Up Podcast. Now there is just a clip. It's just to give you a taster. I have edited it but then the whole idea is to leave you wanting more. A bit like a cheese sandwich really. So to hear the rest of the interview and to check out all the latest editions, do search for Bone Up on any of your favorite podcast apps. It's dead easy to find out there and when you tune in, you will understand why the podcast is doing so well. Keep up the good work, David and Richie.

                                             As for us, there's more from this podcast including our sizable back catalog via the Be Inspired pages on the Imperial College website. Thanks as ever to the team who do all the hard work behind the scenes getting this podcast uploaded and published. And of course, thank you to you for listening. I'll see you in January. Have a wonderful festive break. I'm Gareth Mitchell. Bye-Bye.