Host: Shamini Bundell
Welcome back to the Nature Podcast. This week a new twist in the study of 2D materials.
Host: Benjamin Thompson
And science in Ukraine, one year into Russia's invasion. I'm Benjamin Thompson.
Host: Shamini Bundell
And I'm Shamini Bundell.
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Host: Shamini Bundell
First up on the show, reporter Nick Petrić Howe finds out about a new kind of microscope that could unlock the secrets of 2D materials.
Reporter: Nick Petrić Howe
How do you take a picture of an electron? Being a subatomic particle, a camera isn't going to cut the mustard. So, what you do is use something called a scanning tunneling microscope. This is a tool that has a scanning tip, which is a single atom, which you can kind of think of as like a record needle that moves up and down over a surface.
Interviewee: Shahal Ilani
So there you kind of have the needle that translate the mechanical trenches’ information into acoustic information. So the same thing here is you basically go through the trenches, which are the atoms, and you can basically build a picture of atoms.
Reporter: Nick Petrić Howe
This is Shahal Ilani, a condensed matter physicist, who's very familiar with this technique. As the tip of the scanning tunneling microscope moves across the surface of a material, it reveals the properties of the atoms it's made of. It works because electrons can tunnel, they can jump from the needle to the surface generating current. Researchers can then measure the current to figure out what the material and the electrons are like. This is how they take a picture. This technique was cool enough to win the Nobel Prize back in 1981 and has since led to all sorts of advances in things like nanotechnology, electronics, and even biology. But it has a fatal flaw.
Interviewee: Shahal Ilani
They always measure the properties of electrons at one point at a time, what you do is you probe this or that property at this point, then you move to the next point, measure this property and so on. And this is nice, but you're missing one important crucial factor. So you are missing a direct axis to the fact that an electron in, or most, in most material electrons are basically at the same time at multiple places.
Reporter: Nick Petrić Howe
Because you can only look at one point at a time, it means that the scanning tunneling microscopes may not be showing us all that's going on in a material, especially with regards to what electrons are doing, because to doubly complicate things, when you measure electrons, they stop behaving like waves. Quantum physics does like to make things tricky. But Shahar and his team have developed a new approach that may let them view lots of electrons at once, and with the electron still behaving like waves. The new approach, in a paper this week in Nature, is called the quantum twisting microscope, and it's designed to visualize so called 2D materials, things that are a layer of material only one atom thick, like graphene. In order to visualize one 2D material, the quantum twisting microscope uses another layer of a 2D material on the microscope itself. Here's John Birkbeck, another author from the paper, who's been pioneering this technique to explain how they bring the layers together.
Interviewee: John Birkbeck
So the idea is you have to bring two incredibly small, smaller than the width of a hair materials together, very controllably without breaking them. So, we use what is called an atomic force microscope, which is like a microscope that you use to really control the force. So one layer is kind of sitting on a nice flat substrate happily, and then the other we built on the tip of atomic force microscope, and then we use the incredible force sensitivity to bring them very gently together.
Reporter: Nick Petrić Howe
When the 2D layers are brought together, they interact in a similar way to the scanning tunneling microscope, but with a whole layer of atoms rather than a single atom at the tip, so the team are able to get measurements and essentially visualize electrons in their natural habitats, giving them an idea of what they're doing within a layer rather than just at one point, which potentially tells us a lot more about how materials are made up. The straightforward technique of just bringing two 2D materials together surprised the team as they didn't think it would be so simple. Normally in experiments where 2D materials are interacting, you need very low temperatures and incredible vacuums, as even a single atom in the wrong place can throw everything off. The quantum twisting microscope though, works at room temperature and without a vacuum.
Interviewee: John Birkbeck
It turned out that, you know, nature was very kind to us in the sense that everything kinda works out almost out of the box, right? Almost the first time we did it, it kinda showed like well, it works beautifully as it is but it impressed even us right, we weren't expecting something so, so nice, and so easy.
Reporter: Nick Petrić Howe
It turned out that the attraction between the two materials as they came together was enough to push out any dirt or other atoms that could disrupt the experiment, meaning it didn't need this intense vacuum. Also, it was such thin atomic layers, the team were worried that slight vibrations might ruin their experiments. But again, the attraction seemed to resolve that for them. But the microscope wasn't able to just view electrons in their natural habitat, it had another function. Remember, they call it the quantum twisting microscope. And that's not just to make it sound cool. Here’s Shahal again.
Interviewee: Shahal Ilani
We can bring any two, two dimensional materials into contact and rotate them in situ, okay, and with really good accuracy of the angle like one milli degree, it's really, really tiny change that we can do and we can measure the properties of these materials as we do that.
Reporter: Nick Petrić Howe
Now, this may not sound terribly exciting, but looking at how two different materials interact at different angles can reveal all sorts of extraordinary properties. You may have heard of magic angle graphene, it has been called a wonder material, as it has all sorts of useful properties like superconductivity, and it's made from two layers of graphene misaligned at a precise angle of 1.1 degrees. The new microscope can move to lots of different angles in one experiment, so it’ll move to one angle, do the same viewing of the electrons we talked about, and then move to a new angle and do the same thing again, uncovering the properties of a whole range of angles in one go, which may make it a lot easier to potentially find new magic angles. One person who's excited about this work is Jeanie Lau, another condensed matter physicist. Here was her first reaction.
Interviewee: Jeanie Lau
Oh, I was just like, oh my god, this is so interesting. This is so exciting, and I actually came back and told my students, we should try to make something like this.
Reporter: Nick Petrić Howe
Jeanie wasn't associated with this work, but she first came across the quantum twisting microscope at a talk from the team. She's also written about some of the issues with doing experiments in this field, and thinks that this microscope may go a long way towards resolving them.
Interviewee: Jeanie Lau
One of the challenges faced by the field is that it's very difficult to control the twist angle, and so with this twisting microscope, what it offers is that you can change the twist angle continuously by 0.001 degree resolution. So you can just measure the property, you know, as you change by, you know, this is like a one out of a thousandth degree, and they measure the property changed again and see how the property change continuously, so I think this will be a huge boost to the field.
Reporter: Nick Petrić Howe
Jeanne pointed out that the next challenge will be integrating super low temperatures into the technique, as many of the really interesting properties of twisted 2D materials tend to come out at very low temperatures. This is also where John and Shahal are taking the research next. Even without this though, the team feels like it will have a big impact on the field and may reveal new properties of 2D materials.
Interviewee: Shahal Ilani
While the good thing about this tool is its simplicity as compared to the previous tools, so to make a scanning microscope, typically it's, it's hard and very few groups do it because it requires very stringent conditions. And it turns out that this new machine, the quantum twisting microscope, is much less sensitive to that. I believe that it would make the discovery rate of new things much quicker, we will discover things that we otherwise would be very hard to discover.
Host: Shamini Bundell
That was Shahal Ilani. You also heard from John Birkbeck, and they're both from the Weizmann Institute of Science in Israel. In this piece you also heard from Jeanie Lau who's from The Ohio State University in the US. For more on this quantum twisting microscope, check out the show notes for a link to the paper.
Host: Benjamin Thompson
Coming up, we'll be hearing how Russia's ongoing invasion is affecting science in Ukraine. Right now though, it's time for the research highlights read by Noah Baker.
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Noah Baker
A new fossil found in Mongolia has revealed a Jurassic giraffe, at least a metaphorical one. This fossil is actually an insect with an extraordinarily long skinny neck. The fossil is a lacewing larvae, and it's the oldest of its kind ever discovered, and at least 159 million years old. Lacewing larvae are known for their stylets, fang like head mounted mouthparts that can be used to pierce prey, and this ancient specimen is no different sporting a sizable pair, but they were held aloft by an impressively long neck-like structure. The insect’s closest living relatives are typically found in mountain streams or moist leaf litter and this ancient species probably lived in the bottom of shallow lakes. The researchers hypothesize that the long neck could have allowed it to strike its prey from a distance, hiding the rest of its more conspicuous body. Read more over at the Proceedings of the Royal Society B.
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The world's major coastal cities have added more than 2,500 square kilometers of land to their coastlines between the years 2000 and 2020. That's more than 40 times the size of Manhattan. Scientists analyzed more than 20 years of satellite data covering 135 cities. The team found that 106 of them have expanded their coastlines by filling in wetlands and other coastal water bodies. The most common use of the land was port extensions, followed by residential or commercial uses, then industrial uses. China has added the most land: Shanghai alone added more than 350 square kilometers or 14% of the global total. Also topping the list are Indonesia and the United Arab Emirates, the site of the huge artificial archipelago Palm Jumeirah. The authors argue that these land expansions have often overlooked ecological consequences, and they also note that more than 70% of the new land is in areas that are vulnerable to sea level rise as the climate warms. You can read more on that research in the journal Earth's Future.
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Host: Benjamin Thompson
This week sees the first anniversary of Russia's invasion of Ukraine, and Nature has a number of articles looking at how the ongoing conflict has affected research in Ukraine. Joining me to discuss how international connections and sheer determination are helping keep Ukraine's research system going is Richard Van Noorden, Features Editor here at Nature. Richard, hi.
Interviewee: Richard Van Noorden
Hi, Ben.
Host: Benjamin Thompson
Now, Richard, we're recording this shortly before the anniversary of Russia's invasion, and Nature has a feature looking at where Ukrainian science is 12 months in? What's the picture like now, because there are a lot of things that were unknown, like how many researchers had fled the country at the start of the conflict, for instance.
Interviewee: Richard Van Noorden
So, Ukraine has about 95,000 scientists, and at the beginning of the war, it was estimated that maybe 20,000 or so had left. Now the ministry of science in Ukraine thinks about 6,000 are out of the country but these are very, very rough estimates. So most, by any light, are still in the country. And one of the reasons is that men aged 18 to 60 can't leave except for a few exceptions, like maybe you're a single parent. So most of those who have left, from what we can tell, are women and many of them have children but many people have stayed in Ukraine and in fact, that's where most researchers still are, although a lot of them have moved westwards, and many of them are displaced from where they used to work.
Host: Benjamin Thompson
And in terms of where they used to work, what does the scientific infrastructure look like at the moment? Because of course, many researchers need specialist facilities or equipment in order to be able to do their job.
Interviewee: Richard Van Noorden
So about a quarter of the country's research in higher education institutes have been damaged, and at least four have been totally destroyed, that's according to the science ministry. But the other problem now is the blackouts, so because of Russia's targeting of the energy infrastructure, water supply, heating and electricity is unreliable, and generators and fuel are quite hard to come by, and so there's a lot of elaborate scheduling for experiments and online teaching, because you've got often the students in different places. They don't even always have access to electricity at the same time.
Host: Benjamin Thompson
But despite these problems, research is still going on, and we cover a few researchers and what they're up to in the feature.
Interviewee: Richard Van Noorden
Yeah, so we talked to Kseniia Minakova, who stayed in Ukraine when the war started, and she had signed a collaboration agreement with an American university, and that very same night a Russian missile hit her campus and destroyed her lab. So, they managed to get various microscopes and welding equipment and computers from the rubble and they moved into a space nearby, it's about a quarter of the size, and the American University, Tulane University in Louisiana, sent across a kind of care package of solar cells and cameras and other equipment. And Minakova is now still working, she's collaborating with Tulane, they're working on high efficiency solar cells, and she's just one of 10s of 1,000s of very determined scientists keeping the thing alive and keeping going.
Host: Benjamin Thompson
And one thing that comes across reading the feature is that maybe the essence of assistance has changed. If we think back to when the invasion began, the thrust was very much the research community helping to get scientists out and helping them get set up in other countries. But now it appears that it's more about getting research funding into the country itself.
Interviewee: Richard Van Noorden
It's definitely changed. Thousands of researchers have been placed in universities outside of Ukraine, but there's many more inside Ukraine. And so we talked to Olga Polotska who heads the country's National Research Foundation, which gives out grants, and she's quite pleased that now they've teamed up with Switzerland, with the Netherlands, and with the UK to launch these schemes where grants are going to researchers in Ukraine, and the idea is to ensure that the scientists who are in Ukraine can, can still remain scientists and don't lose contact with the international community.
Host: Benjamin Thompson
And presumably this will have knock on effects on things like collaborations and what have you.
Interviewee: Richard Van Noorden
Yeah, completely. We talked to Ivan Brusak, who’s a young specialist in geodesy, and when the war began, he was actually weaving camouflage nets around Lviv, and he'd like many people we talked to, he said, he's constantly fatigued from the war around him and the deaths of people he knew, but he really values the collaboration he has with Polish scientists that began in July, and this understanding that keeping cooperating gives great motivation for people to keep up the research and teaching within the country.
Host: Benjamin Thompson
And might this be a marker then for how Ukraine scientific collaborations might change in the future, do you think?
Interviewee: Richard Van Noorden
That's absolutely to be expected. I took a look at scientific publications in 2022 and obviously, most of these were submitted to journals before the war began, but even so there does seem to be a signal of Ukraine's international papers being co-authored more with researchers from Poland's and from Europe, and far, far less with researchers from Russia. As I say, this is just a signal starting to come through. And in fact, Germany's science ministry and Poland’s science ministry I know both recommended to researchers that they not collaborate and co-author with Russian scientists – just a recommendation not a mandate. But at least for Ukraine, you're going to see the flavour of its international scientific work change quite radically, and that's already starting to become apparent.
Host: Benjamin Thompson
And if that's perhaps the broader picture of what's happening with money coming into Ukraine. What about the researchers who no longer find themselves in the country? What's the situation for them?
Interviewee: Richard Van Noorden
Yeah, it's difficult to know. There has been one survey of about 600 Ukrainian researchers who left the country but it was done through an organization called Science for Ukraine and other sort of supporting institutions, so this survey really reached people who were already embedded in these sort of supportive networks, and for those people, most of them were women, many of them had children, and of them, around a third were actually continuing their work in Ukraine remotely, although also around a third, so there were sort of some tensions, like their institutions had told people they wouldn't return, and many of them were not really sure whether they would return at the time of the survey, you know, even though the war ended soon, they were asked. So, some people were a little bit worried about the idea of brain drain that they would leave Ukraine and not come back. Now, that's been sort of countered by some people we talked to you said, well, this idea of these fears of brain drain are not really substantiated, people go away from a country they return, even when they don't return, they still pass on their knowledge.
Host: Benjamin Thompson
And so here we are a year in then, and the landscape has obviously changed in terms of the war, and of course, the conflict is still going on, it has to be said, but things as you've laid out, have shifted for researchers in Ukraine as well. What happens now, do we think? What's the feeling about where research and science in Ukraine goes from here?
Interviewee: Richard Van Noorden
Well, definitely the feeling is that there should be more support for people and science in Ukraine, so Nature has run an opinion column from Svitlana Arbuzova, who is a medical scientist, who won a British Researchers at Risk fellowship to allow her to keep on doing her work. And in that column, she calls for science have a proper place in Ukraine's national reconstruction, and notes that the Scientific Committee of the National Council of Ukraine, that she sits on, has already developed proposals to revive science in Ukraine, and she's essentially calling right now for more money for Ukraine scientists from outside. There's been some hopeful signs already, so in February, the European Commission said it would open an office in Kyiv for Horizon Europe, which is the EU’s key research funding program, and some of the other things that are mentioned in our feature. So that's the priority for the scientists right now. But of course, they're all also thinking about the biggest priority of all for Ukraine, which is support for the war efforts, and that's, you know, overrides the science really, and researchers are obviously hoping that Ukraine wins this war and then is able to rebuild its science system.
Host: Benjamin Thompson
Nature's Richard van Noorden there. Head over to the show notes for links to the articles we discussed today and the rest of Nature's coverage on Russia's war in Ukraine.
Host: Shamini Bundell
Finally, on the show, it's time for the briefing chat, where we talk about a couple of articles have been highlighted in the Nature Briefing, and I have been reading a Nature news article today, Ben, all about some changes to clinical trial regulations in the US.
Host: Benjamin Thompson
I mean, we talk about clinical trials a lot Shamini, usually in terms of vaccines. But what's going on here then, what's this story about?
Host: Shamini Bundell
Yeah, so this could apply to vaccines, could apply to over-the-counter medicines, because the change is coming from the US Food and Drug Administration, the FDA, who are the ones who regulate those kinds of things, and they are changing their requirements for researchers and companies seeking approval for late-stage clinical trials. And the aim is to make sure that the diversity of people who are enrolled in these kinds of trials actually match up with the kind of people who are going to be using the vaccines or medicines or whatever it is.
Host: Benjamin Thompson
Which hasn't been the case previously?
Host: Shamini Bundell
Yes, and I think this is something we've discussed before, how representative are trials. People might be familiar that sort of historically, in the past, often, a lot of these trials weren't really representing women in the trial participants. So, there was a report on cancer therapeutics that had been approved by the FDA between 2012 and 2017, and that found that 79% of these clinical trials adequately represented women. So adequately represented means the proportion kind of matches up the proportion of people who have that type of cancer and 79% is actually a massive improvement on what it has been. What's still an issue is things like minority racial and ethnic groups not being adequately represented, and older people, pregnant people and people with disabilities. These groups are sometimes just excluded entirely. So that same report I mentioned, found that, for example, 27% of those clinical trials adequately represented older adults, and only 11% adequately represented minority, racial and ethnic groups.
Host: Benjamin Thompson
And this I'm sure can have some quite significant knock-on effects. Have you got any examples of where this has proved to be a real issue?
Host: Shamini Bundell
Well there was one example mentioned in the article, actually, which was from early on in the COVID-19 pandemic when we were rolling out vaccines, a lot of the vaccine trials didn't include pregnant people. So unsurprisingly, a lot of people who are pregnant were reluctant to get vaccinated, and that actually resulted in a disproportionate number of COVID-19 related deaths in pregnant people compared to the rest of the population, and that's just one recent example.
Host: Benjamin Thompson
And so here we are now then, what is the FDA mandated moving forward?
Host: Shamini Bundell
So what they're requiring of people running the trials is that they submit a plan for ensuring the correct diversity of their trial participants. What's not clear is how they will necessarily enforce that actually happening, some people are concerned about that. But it is a big change in the sort of landscape of ensuring clinical trial diversity in the US.
Host: Benjamin Thompson
And what are researchers saying about these measures then?
Host: Shamini Bundell
So, one bioethicist in the US notes that this is the first time we're going to have companies proactively plan enrollment targets and submit them to regulators. Another researcher notes that this is a way to make researchers think about diversity and could even inspire countries such as the United Kingdom to introduce similar requirements, but some people are worried that maybe it doesn't go far enough. So there is actually an exemption, that sort of waives this requirement in certain circumstances, like during public health emergencies, or if a disease or condition is not considered prevalent in the general population, so one researcher felt that this sort of took the teeth out of the legislation.
Host: Benjamin Thompson
And in a practical sense Shamini, how straightforward is this to do to make sure that diversity is included in clinical trials?
Host: Shamini Bundell
Yeah, it's definitely easier said than done. And you know, this isn't a case of trials will need to say yes, we'll be very diverse, they actually have to have a plan for achieving that. Some of the examples are, you know, people running the trials might need to consider relocating their research sites to places that are like more accessible for members of underrepresented groups. Another issue is that they might need to build some trust in local communities that might have previously experienced quite exploitative medical practices.
Host: Benjamin Thompson
Well a significant development in clinical trials Shamini, I'm sure we'll be keeping an eye on moving forward. But let's move on to my story today and something that I read about on Science Alert and it's based on a paper in PLOS ONE, and it's about snake hearing, okay? And some new research that suggests that hearing might play a more important role in the snake lifestyle than folk previously thought.
Host: Shamini Bundell
Oh, I think my first important question here, because it's not obvious, do snakes have ears?
Host: Benjamin Thompson
I mean, that's an important question Shamini and snakes don't have external ears, nor do they have ear drums, but otherwise, they do have inner ear structures, so their hearing is very different to human hearing, but they can hear sounds right, but it was mainly thought to be, you know, picking up vibrations in their heads, you know, like if someone was walking by, they'd be able to detect the vibrations, for example, but it was always a bit of a puzzle as to whether snakes could hear airborne sounds rather than vibrations in the ground. But as I say, now some researchers have shed a lot more light on that question.
Host: Shamini Bundell
So how do you give a snake a hearing test then?
Host: Benjamin Thompson
Well, what you do is you get a bunch of different snakes, 19 captive bred snakes from five different genera and you put them in a soundproof room, and you play sounds to them. Okay. Now, one of the sounds that the research group tested was a frequency that produced vibrations in the floor, and two of the sounds, were at a frequency only detected through the air and they wanted to see what happened to the snakes, and it kind of varied depending on what sort of a snake it was, and there was one type, the Woma Python, that actually tended to move towards the airborne sound, and when it did so, it kind of lifted up the front third of its body, they call it ‘periscoping’. So, I mean, it's obviously hard to know exactly what was going on, but it seemed to be quite curious, okay. And the researchers think that this is a nocturnal snake, it's a pretty big snake, and it doesn't have many predators, so it doesn't have too much to worry about, so it wanted to see what was going on. But the opposite effects were seen in a bunch of the smaller snakes, so brown snakes, death adders, and taipans. Now, these taipans actively moved away from the airborne sounds, and these are snakes that tend to pursue their prey, but they also need to be aware of predators that will eat them during the day. Okay, so it seems like they're keeping an inner ear out for noises in the environment, and this work suggests that hearing airborne sounds does play a role in snake lives, and it was always assumed that it was kind of taste or vision that were the most important that and that sound was kind of down there somewhere, but no, it seems like snakes are having a little listen.
Host: Shamini Bundell
So what kind of sounds were the snakes actually hearing?
Host: Benjamin Thompson
Well, they played a bunch of frequency ranges up to about 450 Hertz, and what's interesting is that human speech is somewhere around the 100 to 250 Hertz range, so could potentially snakes hear humans? And the frequencies they tested included those around where human speech would be, and they found that at the volumes they were testing, the snakes could hear it. So maybe if you're out walking around in a place that snakes might be found, for example, if you were talking loudly or shouting or singing, maybe the snakes are actually cocking an ear and having to listen to you and slithering off to make sure they don’t get stood on, so yeah, still loads to learn about these animals.
Host: Shamini Bundell
Well, I'm gonna make sure I'm not having any private conversations anywhere where snakes might be listening. Thanks very much for that Ben, and listeners, if you want more on either of these stories, you can check out the show notes, and while you're there, you can also sign up to the Nature Briefing to get more articles like these ones delivered straight to your inbox.
Host: Benjamin Thompson
And that's all for this week. But as always, you can follow us on Twitter, we're @naturepodcast, or send an email to podcast@nature.com. I'm Benjamin Thompson.
Host: Shamini Bundell
And I'm Shamini Bundell, see you next time.