Host: Benjamin Thompson
Welcome back to the Nature Podcast. This week: creating water with holes in it.
Host: Shamini Bundell
And investigating when hominins may walked on two feet. I’m Shamini Bundell.
Host: Benjamin Thompson
And I’m Benjamin Thompson.
[Jingle]
Host: Shamini Bundell
Chemists use all sorts of solvents to dissolve gases for use in reactions. But in many cases, these solvents aren't necessarily very environmentally friendly and they can be unsuitable for medical applications. To get around this, a long-held pipe dream has been to instead transport gases in water. But just one problem: water isn't the best at carrying gas molecules. Now, a team have developed porous water, containing tiny cages that can hold large numbers of gas molecules. And they think that in the future, this method could have an important medical use. Reporter Geoff Marsh spoke to one of the authors, Jarad Mason, to find out more.
Interviewee: Jarad Mason
So, if a person is walking down the street and has a heart attack, the amount of oxygen in their bloodstream begins to rapidly decrease and it becomes extremely important to try to get oxygen back into the body, and the quicker that one can get oxygen back into the body, the better the outcomes are. And one of the most frustrating aspects of oxygen deprivation is that we're surrounded by a ton of oxygen. But when the typical mechanisms for getting that oxygen into the body fail, such as during a heart attack, it becomes really hard to get that oxygen effectively into the body. You can't inject oxygen gas directly into the bloodstream. And so, if you could effectively deliver large amounts of oxygen rapidly into the bloodstream, this would have tremendous implications for emergency medicine and for being able to significantly improve outcomes from events like cardiac arrest.
Interviewer: Geoff Marsh
So, yeah, as you say, you can't just inject pure oxygen. That's a great way to kill someone. So, the ideal scenario is that you could infiltrate some sort of benign liquid that would be fine to go in the body, and infuse that with enough oxygen to buy someone more time.
Interviewee: Jarad Mason
Exactly, and that's something people have been interested in trying to do for the last several decades, both for acute emergency situations like cardiac arrest, but also as a way of developing artificial blood substitutes and overcoming challenges with donated human blood and blood shortages and things like that.
Interviewer: Geoff Marsh
And this is a surprisingly tricky chemistry problem, isn't it, just because of some fundamental characteristics of water itself.
Interviewee: Jarad Mason
Yeah, there's a very fundamental chemistry problem here, and that's how do you get a large density of oxygen or other gas molecules into water or any kind of aqueous environment. Water as a solvent really likes to interact with itself, and it doesn't like interacting with most gases like oxygen, or nitrogen or carbon dioxide, and the amount of gas that can be dissolved in water is typically about an order of magnitude or so less than that which can be dissolved in other common organic solvents. And that's one of the major challenges that was overcome by evolution, which was how do you effectively deliver enough oxygen to large organisms and allow life to become larger in size.
Interviewer: Geoff Marsh
Right, yeah, because blood is largely composed of water, but the oxygen isn't just sort of freely floating in that water, is it? It's in these cleverly packaged molecules called haemoglobin in our red blood cells.
Interviewee: Jarad Mason
Exactly, and the sole function of red blood cells really is just to transport oxygen. 84% of our cells in our body are red blood cells, and they're just packed full of haemoglobin, as you said. Blood contains about an order of magnitude more oxygen than water.
Interviewer: Geoff Marsh
Can you talk us through what's actually happening when, let's say, a molecule of oxygen dissolves in water?
Interviewee: Jarad Mason
Yeah, so in order for a gas to be dissolved in water, water molecules have to move slightly further apart from one another and create space to accommodate that gas molecule, and there's an energetic penalty associated with doing that because water molecules have much stronger interactions with each other. And so, that's in large part why there's so few gas molecules dissolved in water compared to other liquids which are not as strongly associated with one another.
Interviewer: Geoff Marsh
And so, your team’s solution to this was to create permanent cavities in water that will basically let in more gas molecules and keep water out.
Interviewee: Jarad Mason
Exactly, yes. So, we try to kind of overcome this penalty for creating more space for oxygen molecules in water by building that space intrinsically into the solution. And this is building off some very pioneering work from 2015, where researchers first reported in Nature the design of porous liquids that relied on having very large solvent molecules, organic solvent molecules, that could not fit into empty cavities to create empty space inside of liquid.
Interviewer: Geoff Marsh
Okay, so they made molecular cages that were just physically too small to let in those big solvent molecules, and that left room then for the smaller gas molecules to dissolve. But then water itself is a very small molecule, isn't it, so that strategy isn't going to work so well with water.
Interviewee: Jarad Mason
Exactly, you can't rely on size to prevent water molecules from getting inside a pore. If you did, then the pores would also be too small to allow gas molecules to diffuse inside, and so they wouldn't be so useful for storing large densities of gas molecules. So, you have to rely on something else, and so we relied on thermodynamics or the fact that water much prefers to interact with itself than it does to interact with kind of less sticky surfaces. And so, we have networks of cages that are connected together to form nanosized objects that don't like to interact with water on their inside surfaces, and these are microporous materials known as metal-organic frameworks and zeolites. So, their inside surfaces are very hydrophobic, kind of like oil, and they repel water to some degree, but we make the outside surfaces of these particles very hydrophilic, that they have strong interactions with water.
Interviewer: Geoff Marsh
Yeah, I suppose you don't want water-repellent or hydrophobic molecules on the outside of these kinds of cave matrix because otherwise it wouldn't form a nice suspension in the water.
Interviewee: Jarad Mason
Exactly. If the external surfaces are also hydrophobic then the particles will just clump up together, and that does nothing for you for actually increasing the density of gas molecules throughout the entire liquid.
Interviewer: Geoff Marsh
These materials sound incredible. You mentioned zeolites there. Bearing in mind that we have lots of non-chemist listeners, could you just tell me a little bit more about those materials and how challenging is to make them?
Interviewee: Jarad Mason
Yeah, zeolites are materials that have been around for quite some time. They were originally discovered actually all the way back in the 1800s. Many zeolites are naturally occurring porous minerals. They're an extremely important commercial class of materials. One of the things we were excited about, about certain types of zeolites, is that it had been known that they can have very hydrophobic surfaces. And so, what we realised is we could leverage that to create these zeolite nanoparticles that have very hydrophobic internal pores, where we anticipated water would not be able to go inside, but gas molecules would. And because of their high surface areas, we thought we would be able to get really high densities of gases inside water much higher than had been possible with other approaches.
Interviewer: Geoff Marsh
So, if we go back to our initial challenge that you were trying to get a solution to, how do your porous liquids compare in their oxygen density to, say, haemoglobin, or even just like pure oxygen?
Interviewee: Jarad Mason
Yeah, so we're able to get densities now that are about an order of magnitude than the density of oxygen that's present in blood. And we're also able to get about two or three times higher density than pure oxygen.
Interviewer: Geoff Marsh
I'm sure a lot of people are probably going to be a bit confused by that. It seems a bit paradoxical.
Interviewee: Jarad Mason
Indeed, it does seem paradoxical, and that's one of the really powerful things about microporous materials more broadly, including zeolites and metal-organic frameworks, that when you have these very high internal surface areas, so surface areas approaching that of a football field in a very tiny volume, what that allows you to do is to pack gas molecules really closely together. So, if you think about our football field analogy, you can imagine that if the football field kind of has a little bit of a stickiness for a gas molecule, so when gas molecules get close to the surface, they stick to the surface to some degree. This is what's known as adsorption. And the density of gas molecules at the surface or at our football field is much higher than the density of gas molecules in the gas phase above the football field. And so, now you can kind of imagine crinkling up and rolling up your football field to really tiny dimensions to form these nanosized porous objects, and you have all those kinds of sticky gas surface interactions in a very small volume. And that's what's allowing you to pack gas molecules really, really tightly together and get to these much higher gas densities.
Interviewer: Geoff Marsh
So, in terms of these porous liquids working in a biomedical setting, I can imagine that one thing that they need to be able to do in the way that haemoglobin can do near a cell is to let go of the oxygen at the right time in the right place.
Interviewee: Jarad Mason
Yeah, certainly. There’s a few things that these need to do in order to actually be able to be translated into something that's a viable biomedical technology. One, as you mentioned, is to be able to release oxygen, and that actually happens very quickly and effectively in our materials. So, the sticky interactions between oxygen molecules and the porous surfaces are actually very weak, much more weakly than oxygen binds to haemoglobin. And so, as soon as you get to a place where there is less oxygen than is present inside of our porous liquid, oxygen will be quickly released until you re-equilibrate, and this happens in all of our experiments very quickly. Beyond gas release, though, of course for any biological application, biocompatibility is really important, and so you need to design materials that will not trigger unwanted immune responses or anything like that, and that's something we're very interested in pursuing going forward. But this initial work really focused on just establishing design principles and demonstrating that it is possible to make aqueous fluids that can transport such a high density of gas molecules.
Host: Shamini Bundell
That was Jarad Mason from Harvard University in the US. To find out more about this work, check out the link to the paper in the show notes.
Host: Benjamin Thompson
Coming up, we'll be hearing about a new paper looking at some ancient bones to try and pin down when hominins may have started walking. Right now, though, Dan Fox is here with the Research Highlights.
[Jingle]
Dan Fox
Stretchable electronic nerves that can sense muscle strain have allowed paralysed mice to walk, run and kick. Some spinal-cord injuries and neural disorders can cause paralysis by preventing signals from the brain reaching muscles. Scientists have developed electronic devices that can restore this communication. But these devices are often rigid, consume a lot of energy and don't provide feedback on muscle movement and tautness. That feedback is important for producing smooth motion and preventing strained muscles. Now, researchers have attempted to address these problems by developing stretchable, low-energy nerves with strain sensors. The team anaesthetised mice to simulate the effects of a spinal-cord injury or motor-neuron disease and ran their electronic nerves from a transistor outside the body to an implant in the rodents’ hind legs, allowing the mice to generate walking and kicking motions without overstretching the muscle. Read that research in full in Nature Biomedical Engineering.
[Jingle]
Dan Fox
Researchers have spotted what could be the first planetary system to be discovered around a star destined to end its existence in a supernova explosion. There are over 5,000 known planets beyond the Solar System, but most of them orbit relatively lightweight stars, no more than roughly twice the mass of the Sun. Whether planets can form and survive around stars big enough to go supernova remains relatively unexplored. A team of researchers have been using the European Southern Observatory's Very Large Telescope to search for planets around 85 massive stars. One of the stars is μ2 Scorpii, a star 474 light years away from us and about 9 times the mass of the Sun. Nearby, the astronomers spotted a planet roughly 14 times bigger than Jupiter, along with hints of a second even larger object closer to the star than the first one. The presence of two planets around such a massive star suggests that large stars circled by large planets could be more common than expected. Read that research before μ2 Scorpii explodes in Astronomy and Astrophysics.
[Jingle]
Interviewer: Benjamin Thompson
Bipedalism – or walking about on two legs – is one of humanity's defining characteristics. But like so many of the things that make us us, exactly when this mode of getting about evolved is unknown. This week in Nature, there's a paper building on some earlier work suggesting that it may have been several million years ago, in what is perhaps one of the most ancient hominins yet discovered. But as is often the case with palaeoanthropology, things are quite complicated. So, to find out more about the work, I'm joined on the phone by Ewen Callaway, a senior reporter here at Nature, who's been reporting on the story. Ewen, how're you doing today?
Interviewee: Ewen Callaway
I’m good. How are you?
Interviewer: Benjamin Thompson
Yeah, doing okay. Thanks for joining me today. Now, this story actually begins about 20 years ago with the discovery of some bones that were found in Chad, right?
Interviewee: Ewen Callaway
Yeah, this is surrounding a species – I'll use that term instead of hominin and I'll explain why a bit later – called Sahelanthropus tchadensis. It was discovered as a result of an expedition from French and Chadian researchers in the early 2000s. And in 2001, I think, they found a fairly complete but really battered skull that was very swiftly described in Nature. And this skull – it’s about 7 million years old – they nicknamed it Toumaï, which means ‘hope of life’ in the local Daza language. And the researchers argued that it was, based on its shape, a hominin. And so, for those of us who aren't up on our paleo lingo, a hominin includes humans and all fossil species that are closer to the human lineage than the chimp lineage. So, 6-10 million years ago, the ancestors of humans and chimps split, and everything on the human line is a hominin. Everything on the other lines is not. And so, that was their argument. They also argued, on the basis of this skull, that where the spine entered the skull, it was at an angle such that it was indicative of bipedalism. So, that was their argument: this 7-million-year-old thing is a hominin based on the shape of its skull. And it walked upright, and that would have made it the earliest known hominin yet discovered.
Interviewer: Benjamin Thompson
So, that was the paper from 20 years ago then, but let's fast forward to now, and there's a new paper out, which is looking at some different bones.
Interviewee: Ewen Callaway
Yeah, so they were uncovering these remains. I think, when you see a skull, a hominin skull or even a large primate skull, I'd say, it's pretty darn clear. But then you’re tromping around the desert and picking up lots of other bones that might be from different animals et cetera, and it's all collected. So, in 2001, I think around the same time that Toumaï the skull was discovered, some other remains were discovered and put in a box or something like that, just kind of there for storage. And a few years later, some researchers not affiliated with this team but at the same university, they were just kind of looking through these bones as part of like a training exercise for a student. And this student identified one of the bones as a primate femur, or part of a primate femur, just the shaft so it doesn't have either end attached to it. And other researchers, I think part of this team, identified an ulna, which is an arm bone. And then a couple years later, this expedition, these researchers in Chad, found another arm bone. And so, this paper that we're talking about, is describing this femur shaft, and these two arm bones that were found between 2001 and 2003, but they have not been properly or fully described until now, 20-some years later, which has led to quite a lot of speculation and intrigue and controversy surrounding these remains, to be honest.
Interviewer: Benjamin Thompson
And what sort of intrigue are we talking about?
Interviewee: Ewen Callaway
Well, the femur, in particular, has gotten a lot of attention because a femur, even one that's not fully complete, might say a lot more about bipedalism. And so, the researchers who uncovered the femur and got to look at it for, I think it was just a few days in 2004 or something like that, they published a paper in 2020 finally, saying, based on their brief analysis, it does not look like an upright, walking hominin. And two years later, this paper comes out, which is a much more careful analysis from the French-Chad team and they said it does. And so, that's kind of where it stands. I mean, there are these arm bones as well, which look really quite ape-like and similar to what we think early hominins had. Possibly, they were quite adept at tree climbing and this was a trait that was retained in the hominin lineage for quite some time, all the way until a few million years ago with Lucy. Maybe the last time we were talking about her – this is Australopithecus afarensis – it's a really famous fossil. We think she might have met her and falling out of a tree. So, it's this kind of mix of traits behind this really controversial fossil.
Interviewer: Benjamin Thompson
So, there are some differences of opinion there clearly. What are other people you spoke to saying about it?
Interviewee: Ewen Callaway
I've gotten a diversity of opinions. I think some people who say, yeah, this is probably a hominin, probably bipedal, but we've got some other candidates, maybe a little bit younger than Sahelanthropus, that are probably a little bit closer to the lineage that led to our kind, and figuring out the relationship between these early hominins is not really helped by this paper. I've got some people who are really critical of the evidence that the researchers put forward in favour of bipedalism. So, it really spans the gamut. There's a News and Views author – I didn't speak with him but I've read his really excellent essay – his name is Dan Lieberman. He’s a paleoanthropologist at Harvard. He said the Sahelanthropus femur doesn't have smoking gun traces of bipedalism, but it looks more like that of a bipedal hominin that of a quadrupedal ape. And so, on the balance of evidence, he's saying that this looks like a biped, but maybe not. A lot of people aren't going to be convinced, and I don't think this paper is going to change a lot of people's opinions.
Interviewer: Benjamin Thompson
And what do you think it will take then to put this disagreement to bed?
Interviewee: Ewen Callaway
I mean, maybe more discoveries from the species? Certainly, that would be helpful. I think that's what it would take. I mean, now that the bones have been described, they're out there for other people to hopefully analyse. I mean, there are some people I spoke with suggest to me that just because this thing potentially walked on two feet, that doesn't make it a hominin. I mean, we really don't know what the common ancestor of humans and chimps looked like and how it walked. And we don't really know when bipedality developed on our lineage. So, there are just a lot of questions. And so, I think finding additional fossils, not only from on the hominin lineage but also in the chimpanzee lineage, could be really illuminating about what great apes looked like in this period, you know, 10 to 5-6 million years ago. Was there a lot of diversity, or is it clear that this one's in the chimp box and this one's in the hominin box? We just don't know.
Interviewer: Benjamin Thompson
And finally then, I mean, why is it important to know when hominins started walking? Why do we need an answer to that question?
Interviewee: Ewen Callaway
I mean, as you said in the intro, this is one of the defining traits of our lineage. I wouldn't even call it just curiosity. But it's just interesting, isn't it?
Interviewer: Benjamin Thompson
Nature’s Ewen Callaway there. Head over to the show notes to find a link to his news article and to the paper.
Host: Shamini Bundell
Finally on the show, it's time for the Briefing Chat, where we discuss some of the stories that have been highlighted in the Nature Briefing. So, Ben, what have you found for us this week?
Host: Benjamin Thompson
Well, Shamini, I've got a story that was reported on in The Guardian, and it's based on a paper in Science Advances, and it's all about megalodon, the extinct giant shark that lived millions of years ago and one of the biggest predatory fish of all time.
Host: Shamini Bundell
Oh, you know how I love extinct things, especially giant, scary, extinct things. This is a type of creature we've known about for a while though, right?
Host: Benjamin Thompson
Yeah, that's right. I mean, so megalodon is obviously kind of the poster shark for giant, huge extinct creatures, right? But we don't know a huge amount about it. Like you can get a lot of teeth right, they’re about the size of your fist, right, but in terms of what the actual animal itself looked like, it’s a bit more of a mystery because, of course, its skeleton was mostly made of cartilage, right, so it didn't preserve well.
Host: Shamini Bundell
Oh.
Host: Benjamin Thompson
Yeah, so it's been hard to kind of work out what this animal looks like. You think about dinosaurs, right, their bones preserve pretty nicely, right, so you can sort of dig them up and then reconstruct what the animal would have looked like. But that's not necessarily the case here. So, in the past, scientists have had to make sort of inferences from the teeth and comparing it to things like great white sharks as well, which are obviously an apex predator from today, and try and work out what the animal might have looked like, right? And I think estimates say it would have been about 20 metres long, something like that. But now, some researchers have gone about it in a slightly different way and are having another go to see what megalodon might have looked like.
Host: Shamini Bundell
Okay, so beyond just, hey, these teeth are sort of like great whites but even bigger therefore megalodon must have been even bigger, what other evidence is there out there about the body shape of this creature?
Host: Benjamin Thompson
Well, body parts are vanishingly rare, as I say, Shamini, but not completely absent, right. So, for example, in a Belgian museum, there are these portions of vertebrae from the megalodon, right. They've been there since the 1860s, right. And so, what these researchers have done is used these to make a 3D model of what this animal might have looked like. And so, looking at them, it's suggested that this animal died at 46 years old, right, and lived about 18 million years ago. And so, what they've done is they've taken these partial vertebrae, extended it out to imagine what all the vertebrae would look like, put in a bunch of teeth, which obviously are ten a penny, relatively speaking, and kind of thrown in a little bit of a great white morphology as well, right, into the mix to try and flesh out the bones, so to speak, and then made a computer model of what this animal might have been like.
Host: Shamini Bundell
And now that they've got a sort of 3D model of this particular individual, what does it tell us?
Host: Benjamin Thompson
What this allows them to do, Shamini, is to try to work out the biological properties of this individual animal. And so, this 3D reconstruction, they suggest that the animal was about 16 metres long, which is longer than a bus, which also puts it within the kind of estimate for how long scientists thought megalodons might grow. They suggest it was probably 61 tons, which is very, very heavy indeed, and that its mouth span would have been about 2 metres across, right, so that's about as tall as me, right? So, I could have just gone in, without crouching down, into its mouth, had I lived 18 million years ago. And they suggest that maybe this individual had a cruising swimming speed that was actually higher than sharks that are alive today. And all these facts are super interesting, of course, but I think what they're inferring as well is maybe it gives a bit more of an insight into the megalodon’s lifestyle. They say that it needed a huge amount of calories, and its mouth was so big, it could really kind of devour giant other predators, for example. Something the size of a modern-day killer whale, it could just gobble it down and a few bites, right. And they suggest that this animal could have been quite good at really long-distance migrations and doing it quite quickly, which would increase the chance it would have of coming across things to eat because it really needed to get these calories on board.
Host: Shamini Bundell
Oh, this sounds like a terrifying but awesome mega-predator. I guess I suppose I'm glad megalodons aren't around anymore.
Host: Benjamin Thompson
Yeah, and what happened to them, I guess, is one of the big sort of unanswered questions. And the reason for their extinction is, well, it's unknown. Maybe they were outcompeted by smaller, more mobile sharks. Maybe it was habitat loss. But I think this work is interesting because, of course, it is a lot of extrapolation as well. There's still some great white data in there. And as we've covered on the podcast before, there's some evidence about what megalodons ate, right, from looking at the chemistry of their teeth. Suggestions that they like to eat top predators, for example. And so, maybe their extinction altered the food web and allowed whale species to thrive when they would previously be predated. I mean, there's a bunch of questions about this animal, and I guess we'll never really get to the bottom of them. But this work kind of gives a little bit of a new flavour about what life might have been like for this 46-year-old megalodon 18 million years ago.
Host: Shamini Bundell
And next time someone wants to make one of those terrifying giant shark horror movies, they’ve got some more scientific basis for it.
Host: Benjamin Thompson
Yeah, that's what those movies are missing, Shamini, definitely. Anyway, let's move on. What's your story today?
Host: Shamini Bundell
So, I've been reading a news article in Nature about a new paper out in Science, about a class of chemicals that are sort of nicknamed ‘forever chemicals’.
Host: Benjamin Thompson
Yes, I've heard about these things. They're often found in like cooking pans and stuff like that, right?
Host: Shamini Bundell
Yes, a lot of these chemicals are sort of oil-repellent water repellents used in things like, yeah, like non-stick coating, waterproofing, firefighting foam, things like that. And the fact that they don't break down easily is like a great property in some situations, but it's starting to have potentially environmental and health impacts. But this new paper shows a possible new way to neutralise some of the dangers of these chemicals.
Host: Benjamin Thompson
Right, and what are some of these potential dangers then?
Host: Shamini Bundell
Yeah, so these are substances, these forever chemicals, are actually per- and polyfluoroalkyl substances, or PFASs, and they are basically sort of carbon chains with a very strong carbon-fluorine bond. And as well as being very useful for all sorts of things, they’re also hard to get rid of. So, if these products are going into sort of waste disposal, these chemicals are not easily dealt with. They tend to accumulate in the soil, in the water, even in humans, actually. So, a 2015 study found these PFASs in the blood of 97% of Americans, and they may be linked to medical conditions such as thyroid disease, high cholesterol, cancer, potentially.
Host: Benjamin Thompson
And so, yeah, there's a drive then to try and clean them up.
Host: Shamini Bundell
Which, unfortunately at the moment, has been very difficult. So, you can treat them to basically break them down so that they can be disposed of properly. But so far, the processes needed were requiring very high pressures, temperatures above 1,000 °C, and are just generally very expensive, which is where this new research comes in and hopefully has actually come across a cheaper and more practical solution.
Host: Benjamin Thompson
And what is that solution then?
Host: Shamini Bundell
Well, there's some chemistry involved and, as I mentioned, these chemicals have a very strong carbon-fluorine bond and actually, what this new chemical process does is avoid targeting the really strong bond and go to another part of the chemical, knocking off sort of another section of it that starts a cascade reaction that results in this big, long chemical being broken down into then harmless products. So, this was sort of discovered by a group of scientists who sort of realised that it worked and then used computational analysis to kind of work out actually what was going on with the with the chemistry there, how it was actually working, which is super useful because if they can work out what exactly is going on with the method that they found, they might be able to develop methods that work for this whole class of chemicals, not just the ones that they were working on.
Host: Benjamin Thompson
So, they're testing a subset of these chemicals then and they extrapolate it out. But are there any downsides, I guess, to this new technique?
Host: Shamini Bundell
Well, some of the same downsides still apply, which is that it can be quite hard to kind of isolate the chemicals from things like groundwater and from waste to actually treat it. And this chemical process involves another chemical called DMSO as part of the reaction, but that might not be terribly practical. You can't put it down a sewer. You then have to dispose of that chemical as well. So, this isn't the single perfect solution for all treatment, but the better understanding in general could lead to that kind of a solution.
Host: Benjamin Thompson
Well, a problem that is looking for a solution then, Shamini, and we shall watch this space, as they say. But let’s leave it there for today’s Briefing chat. And listeners, if you'd like to know more about either of these stories, head over to the show notes, where you'll find links to them, and also a link to where you can sign up for the Nature Briefing to have even more stories from the wide world of science delivered direct to your inbox.
Host: Shamini Bundell
That’s all for this week. As always, you can keep with us on Twitter – we’re @NaturePodcast. Or you can send an email to podcast@nature.com. I’m Shamini Bundell.
Host: Benjamin Thompson
And I’m Benjamin Thompson.