Host: Nick Petrić Howe
Welcome back to the Nature Podcast. This week making electronics faster with metadevices.
Host: Shamini Bundell
And how to best research the effects of social media on teen mental health. I’m Shamini Bundell.
Host: Nick Petrić Howe
And I’m Nick Petrić Howe.
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Host: Nick Petrić HoweFirst up on the show, a new way to make super-fast electrical components. As technology becomes more advanced, and we start seeing things like artificial intelligence, or 6G communications coming along, our tech is going to be transmitting more and more data to keep up.
Interviewee: Elison Matioli
All of these applications require fast electronic components. And the problem is that we are reaching to a point where the components cannot operate at the speed that they are required.
Host: Nick Petrić Howe
This is Elison Matioli, an applied physicist and electrical engineer who's trying to make sure that our components can keep up. In the past, increasing the speed of phones, computers, etc. has been achieved by making the electrical components that make them up smaller. For example, transistors are a key building block of modern electronics. They're little switches that control signals on things like computer chips. By making them smaller over the years, engineers have been able to increase their speed and pack more onto chips, enabling us to improve computers over time. But at a certain point, you start to run into problems. Get small enough and quantum effects, amongst other things are going to give you a headache. You start getting a lot of resistance, which limits the speed of signal transmission. So, getting smaller stops being a solution.
Interviewee: Elison Matioli
So we were trying to find an approach that can basically solve these limitations that the current approach of making a device smaller and smaller have.
Host: Nick Petrić Howe
This is no small feat. A goal in the field for some time has been to get electronics passing data so quickly that it enters terahertz frequencies. That’s cycling data, trillions of times per second, when your current phone or computer may only just go into the billions. It's such a challenge that is known as the terahertz gap. But in a new paper in Nature this week, Elison and his co-author think they've developed a material that switches signals on and off at these terahertz speeds. And they did it by creating something they call a metadevice.
Interviewee: Elison Matioli
There's the word that we borrowed from the field of optics, where generally means that a material has been patterned in a certain way that brings properties that are not natural to that material.
Host: Nick Petrić Howe
Such unnatural properties include things like terahertz signal transmissions, and as Elison alluded to, patterning the material appears to be key.
Interviewee: Elison Matioli
Instead of shrinking the size of the device. We rearranged the electrodes in a way that we can form some patterns in subwavelength distances.
Host: Nick Petrić Howe
Let's break that down a little bit. In a conventional electronic device, electric signals flow in and out through electrodes. At the electrodes, electric current can build up which creates resistance, thus slowing down the passing of signals, which isn't great if you want those superfast terahertz speeds. In this metadevice, the electrodes formed a pattern resembling interlocking fingers. To cut a long story short, this pattern meant it was possible to control the signals passing through the metal device at very specific active regions. This avoided the buildup of current, reducing the resistance, which allowed signals to be passed much more rapidly.
Interviewee: Elison Matioli
And the result is that we can confine currents only in the active part of the device rather than having this current spreading under unwanted regions, so that made the device much faster, and we could increase by almost a tenfold the frequencies.
Host: Nick Petrić Howe
By reaching such speeds, the metadevice could theoretically enable new technologies like 6G communications and more advanced computing. Of course, there's more research to be done, and our computers and phones are made up of more than just fast switches like this. But Elison and his co-author believed that what they've developed here could be the foundation of more superfast electronic devices in the future. They also think that there's not much more needed for these meta devices to become a reality.
Interviewee: Elison Matioli
Honestly, the type of devices and technologies are very similar to what exists in the real world. So, there is not much needed in terms of just applying these concepts into, you know, future devices. What is needed, and that's the vision of our lab, is basically making novel kinds of device that can provide other functions other than switching as we are demonstrating here, but also amplifying signals. That will be a very needed thing in the future.
Host: Nick Petrić Howe
That was Elison Matioli from EPFL in Switzerland. For more on that story, check out the show notes for a link to the paper
Host: Shamini Bundell
Coming up, can more granulated research help show how social media use is affecting mental health in adolescence? Right now, though, it's time for the research highlights with Dan Fox.
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Dan Fox
Waiting for basic services, like seeing a doctor or getting a haircut, feels like a universal experience. But in the United States, it seems some people are waiting longer than others. Research has shown that factors such as race and ethnicity can influence how people use their time, including how long they have to wait for goods and services. But little is known about how income affects waiting. To find out, researchers examined 17 years of data from a government-led survey on how people in the US spend their time. The results for a typical day aren't particularly striking. People with low income spend an extra minute waiting for services relative to their high-income peers. But that adds up to six hours lost every year. A figure the authors say is a conservative estimate. Don't wait to read that research in full in Nature Human Behavior.
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Dan Fox
How do you hear an alarm if you're asleep? When a person is awake, the brain's information relay center known as the thalamus is largely responsible for sending sound and other external sensory information to the cortex, the region responsible for cognition, but this circuit mostly shuts down during deep sleep. Now, researchers have identified a specialized neural circuit that works during this stage of slumber to ensure that you hear that alarm bell ring. To pinpoint the cells responsible, the researchers used a technique called optogenetics. Introducing a gene that encodes a light responsive protein into an animal's neurons. Neural activity can then be controlled by flashing a light. Working with mice, the author's identified a specific cluster of neurons in the thalamus known as mediodorsal thalamic neurons that were illuminated roused animals that were deeply asleep. Further experiments revealed that the medio dorsal phenomic neurons were stimulated by signals from another group of neurons in a region of the midbrain, which connects the brain to the spinal cord. Read that research in full in Current Biology.
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Host: Shamini Bundell
In the last 10 years, levels of social media use among young people have skyrocketed. Alongside this, there's been a significant increase in reported levels of mental health issues among adolescents. And there's been much discussion and debate about whether or not there's a causative link between these two trends. But concrete evidence has been hard to come by. Data's often in the hands of private companies, and how people actually use social media is quite varied. There are different apps, websites, and activities you can do, all of which count as using social media. And this lack of evidence is becoming an issue as governments start to develop and enact legislation to protect young people from harmful content online. So how can scientists get a better understanding of what's going on? Well, this week in a comment article in Nature, researchers are arguing that rather than just lumping young people into one homogenous group, future studies should consider who young people actually are, and how where they are in terms of their development could influence the potential impacts of social media use. One of the authors of the comment is Amy Orben, an experimental psychologist from the University of Cambridge here in the UK. Reporter Benjamin Thompson gave her a call and asked her why current studies have tended to treat adolescents as all the same.
Interviewee: Amy Orben
So, people often see young people as the canary in the coal mine. They're the first people who use a new technology and so adolescents are often the population we study first, whether that was about the radio in the 1940s, or the television 1960s, or now social media in the 2020s. But for the last five to ten years, we have seen adolescents at this sensitive group. This group we really want to understand and study because it's important for us to safeguard them and to support them. We have considered adolescence as being one homogenous group. So yes, we've lumped together 10-year-olds and 15-year-olds and 20-year-olds, often in research. However, adolescence is a time of major change, where young people start becoming really interested in what their peers think about them, for example, or where they go through pubertal and bodily changes that make other people start treating them differently. And so all these changes might really impact how they are themselves impacted by technologies. But we don't really know a lot about that yet, because a lot of research has often focused on smaller samples of specific age groups, or they've averaged bigger bunches of age groups together, I think, because we're just at the very beginning of trying to understand these sorts of relationships.
Interviewer: Benjamin Thompson
And you describe some efforts from yourself and your colleagues to take some early steps into that sphere, I guess, which is looking to segment young people more by age group and see how their social media use potentially affects their mental health. What did you find?
Interviewee: Amy Orben
What we found was that the link between social media use and while being changed over time, and it was changed in different ways for young people who reported as males or females. So, for the female group, we found that there were two times in adolescence where social media use predicted a decrease in life satisfaction one year later. And that was at age 11 to 13. When young girls start using a bit more social media than their own average, that predicted a small decrease in their life satisfaction one year later, and that was the same at age 19. For the group reporting as male, we found that this first window of sensitivity to social media was slightly later. So, it was between the ages of 14 and 15, while the second window at age 19 stayed the same. And this is really interesting for developmental researchers, because we do know that girls enter puberty earlier than boys, and so it was very interesting that we saw the female group show this window sensitivity to social media earlier than the male group. But then, at age 19, they were about the same and that might be because they are then going through processes, which are the same across all young people, for example, that's a time when there's a lot of social changes, because young people leave school to go to university for their education or work, and so that opened up a whole new range of research questions for us to consider.
Interviewer: Benjamin Thompson
And were you surprised by this result when you saw it?
Interviewee: Amy Orben
This research was exploratory, so we still want to replicate it with more research. And I wouldn't say that we've completely predicted what we'd found. But I think it now gives us a lot more things to explore. How does puberty relate to social media use? Or how does all these changes in the way we think that we experience when we're teenagers influence how we experience social media, for example, there has been a huge amount of research, which has shown that young people become really sensitive to the comments they get from their peers and there's been a huge amount of research in that area. And you started thinking, well, maybe an online environment that starts quantifying feedback and giving you likes and very concrete approval or disapproval might actually be more impactful in that time, where you're, for example, really prone to interpreting or being influenced by the feedback of your peers.
Interviewer: Benjamin Thompson
In your comment you describe this as the missing link. This dividing up of young people by age something is really, really important to this area of research. What needs to be done to make sure that it is embedded in further studies moving on, do you think?
Interviewee: Amy Orben
So, I think the next steps is just for research to not just study one age group, but to study in many different age groups, and have the necessary amount of young people to be able to do that. But then also to then use the right types of statistical models that don't treat a 10 and a 15-year-old as being the same but allow those to vary, and I think then once that foundation is set, we can start understanding a bit more about these relationships between social media use and mental health over adolescence. But I think the then the next step would be to do more targeted experiments or studies looking at how specific developments in adolescents interact with social media use.
Interviewer: Benjamin Thompson
Which seems like such a straightforward thing to say, like researchers is sure to do this. What are some of the stumbling blocks to making that happen?
Interviewee: Amy Orben
There are many and I think these stumbling blocks aren't just important to the question about social media, but to the question about how we study digital technologies in the 21st century, because after social media, there'll be new technologies that matter to parents, policymakers, and the public. One of the major stumbling blocks is that technology moves really fast. There are new platforms developing all the time. And scientists still really kind of stuck in the 20th century in the way that we do a lot of things. And so, we need to find a way to increase the speed in which we do research to still be relevant. But then the next thing is that we need really good data about what young people are doing online and we don't have that at the moment because that is being held by private digital companies that control the online spaces, so I think this is an ongoing problem around what transparency we need in the digital space to even understand the impact it's having on us in our society.
Interviewer: Benjamin Thompson
And researchers, like yourself, I'm guessing, are fundamentally doing this research to understand the issues that young people face and help ultimately improve their mental health. If this comes to pass what you've called for, and it's included in future studies, what difference do you think you could make to the lives of young people?
Interviewee: Amy Orben
The clear emphasis is that we need to start creating things that help young people, either those who are experiencing mental health disorders, or those who are vulnerable. And I think to do that, we need to start creating interventions or ways in which we can intervene in young people's lives, and those need to be very targeted. We can't just say, oh, let's shut down social media, it's not going to happen. So as researchers, we need to have very targeted recommendations of what we should do. And I think being able to think about age and development and how that impacts a link between social media use and mental health will be really valuable, because maybe we can target certain interventions to certain age groups, and really understand what makes certain young people vulnerable.
Host: Shamini Bundell
That was Amy Orben from the University of Cambridge. To read her co-authored comment, look for a link in the show notes.
Host: Nick Petrić Howe
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. Shamini, what have you brought for discussion this time?
Host: Shamini Bundell
So, I wanted to tell you about some research that came out in Nature and I've also made a film about it on our YouTube channel, and it's basically a team that have sort of designed an artificial seed carrier, and they have designed it sort of based on a real-life seed or sort of several real-life seeds found in nature and they sort of studied those and have made their own version.
Host: Nick Petrić Howe
And I guess my first thought is, why do we need a version of a seed carrier? Are seeds not good enough?
Host: Shamini Bundell
Well, different seeds of different species obviously have different properties based on what they need to do, so you sort of think about a dandelion seed, it's mainly wanting to be sort of floating on the wind, and the seed that they were looking at is a seed that is self-burying, so it can sort of twist itself down into a little nook or crevice in the ground, and thus sort of get itself under the surface, which is a better place for seed to be when it wants to germinate, and the reason that that is a sort of useful thing for a seed carrier to have is that across the world people are sort of starting to develop methods for aerial seeding, so basically seeding from the sky, now this could be useful just because you don't have to drive a tractor all the way over a huge patch of land, it could be much faster, it could be that area that you want to seed is harder to get to, it could be somewhere something remote like you want to replant a forest, for example. And in those situations, you can just sort of drop seeds and people are sort of doing that, but they have a really low germination rate, and that's at least partly because the seeds are lying out in the sun, they're getting dehydrated, they're potentially getting eaten, and this team thought you know what, the one thing that would really help this is if those seeds once you've dropped them, were a little carriers that could bury themselves just like these certain seeds found in nature.
Host: Nick Petrić Howe
Oh, okay. I had no idea that there were seeds that could bury themselves. So how does this work? In the sort of natural sense, and then I guess, how have they improved upon this sort of natural self-burying seeds?
Host: Shamini Bundell
Oh, yeah, well, it's very clever. So, the main seed that they were looking at is from a plant called Erodium, and basically, it looks like a little sort of hairy seed like very, very, very tiny hairs, with a sort of tail coming off the end, and that tail sort of coils out from the seed initially in quite tight coils, and then a sort of bigger, longer, slightly bending tail on the end. And the material that this sort of seed is formed off is such that when the seed gets wet or dry, depending on the moisture, that big tail bends, or unwinds, so what you get is you get these Erodium seeds, that sort of land on a piece of ground somewhere, hopefully already in a sort of slight crevice over there at a slight angle and this tail is sort of wiggles around, and as the tail wiggles, the seed part goes into the ground, the hairs stop it coming back out again, and you've also got this sort of coiled bit, sort of like a drill, so it can sort of twist more easily down into the earth.
Host: Nick Petrić Howe
And so that's how it works in nature. And then what have the researchers done to make this better?
Host: Shamini Bundell
Well, it's very similar, I think, you know, part of their plan was definitely sort of trying to find a way to recreate this. So they had to find the right material, for example. And they ended up making these little carriers out of a particular type of wood and it had to be I mean, biodegradable is a good one, if you're trying to sort of plant your crops, or replant a forest, and they had to sort of chemically treat it so it was kind of bendy enough. And it had to have this sort of property of it would kind of, you know, unwind and coil up when it gets wet and dry. But they did then, as they were sort of studying, okay, how does the geometry of this work? What are the kind of optimal shapes involved to get it to sort of bury itself most efficiently? They did come up with yeah, what could be seen as a sort of improvement on nature, perhaps, which is they developed a design, which has like three tails, with helicopter blades coming out the top rather than one. And the reason that that was helpful in their tests, certainly on sort of flat surfaces, is that when the seed lands, those three tails, sort of like prop it up like a tripod, so that the seed end is always sort of pointing down at a bit of an angle into the earth. So, it doesn't like the rhodium might need to find a sort of little bump or crevice to wiggle its way into, it's already kind of got a good angle to be working its way downwards as then the sort of winding uncoiling motion drives it around.
Host: Nick Petrić Howe
So then, how much better is this then nature? Or is it just, we can use this for all sorts of things, so we can use all different kinds of seeds and that's going to be really useful.
Host: Shamini Bundell
So that was my question at the beginning was like, wait a second, you've improved on nature so much, where’s nature been? What you're doing evolution? But of course, evolution has a lot of other factors, it has to consider when producing the seeds and growing them and sort of scattering them, so they need to do a lot more and sort of fill other functions. Whereas what we can do is, you know, design something specifically for exactly what it needs to be such as like, this is perfect for being dropped from a drone in this sort of particular area over this particular soil type of particular weather, theoretically, but you can see some of this on our YouTube channel, I'll just I'll just give you a quick plug, you should go to youtube.com/naturevideochannel, and check it out, because then you can actually see them doing their little digging. I don't know if it's, it's maybe hard to believe, but they do they spiral their way down into the soil, so check that out.
Host: Nick Petrić Howe
I certainly will. I want to see these little drill type things going into the ground. For my story this week, though. I've been reading about He Jiankui who you may remember as being the scientists behind the CRISPR babies. Well, he has popped up again at an event. And some scientists are not so happy about this.
Host: Shamini Bundell
Right. Okay, so this was a sort of controversial experiment on on CRISPR-ing humans from a few years ago, was it?
Host: Nick Petrić Howe
Yeah, that's right. So back in 2018. He Jiankui performed experiments on embryos that were then implanted into people. So, he was editing CCR5, which is a HIV co receptor, with the idea that will make them resistant to HIV, these babies, because their fathers were HIV positive. However, such experiments are banned in China. Where he does his research and also across many other countries in the world, and there are a lot of ethical considerations when it comes to editing embryos for implantation. And as a result of all this, he went to prison for several years. But now he is out. And he attended a bioethics event, and was talking about his sort of next steps.
Host: Shamini Bundell
So, he gave a talk at this event?
Host: Nick Petrić Howe
He did indeed. So he has been talking about how he set up a not-for-profit lab, developing affordable therapies for hereditary diseases. So, sort of in the same line, as it was before. And this has, well, frustrated a lot of researchers, especially because during this talk, he wouldn't answer any questions about the CRISPR baby work that he did before, and for a lot of scientists, this is quite concerning when there have been these unethical experiments done in the past. It sounds like he's going to do something akin to that and he's refusing to talk about the things that have happened before. One person described this as just a publicity stunt, and it shows that he really doesn't have much credibility in the eyes of his peers.
Host: Shamini Bundell
Are the kind of things that he's proposing to do now legal experiments and people think he's trying to sort of brush the previous work under the carpet? Or are people also concerned that his ongoing future research is also going to break the rules that were laid out?
Host: Nick Petrić Howe
A bit of both I think, the research he's proposing isn't to do with any research that's banned. So, he's actually looking at drugs that could do, sort of, gene therapy. So, these are things that you take, and they, you know, cause some alterations to DNA, which can help with certain kinds of hereditary diseases. So that is research that people are able to do, because it's not like a permanent change in someone, and it's not in someone who hasn't been born yet, so it's different to what has come before. But I think many scientists also found it a bit strange, because he just spent a lot of time just describing the basics of gene editing, which is a bit strange for a big conference, and then just, you know, refusing to answer questions about his work. So it was a little bit strange. And one person described it as bordering on being insulting.
Host: Shamini Bundell
And I wonder how much impact these kinds of reactions are gonna’ have on his work? Because obviously, to some extent, collaborations and science are, are really important, but if he's got his own funding, I suppose he can just carry on as long as he's not doing anything illegal.
Host: Nick Petrić Howe
Yeah, I mean, it's a tricky question, because it's hard to know exactly what it is he thinks or how he responds to the scientific community. He did say in his talk, that research must accept moral and ethical constraints, but he didn't really expand upon that. And the other problem is actually kind of what we're doing right now is some researchers worry that all this publicity is just diverting attention from actually discussing some of the real ethical issues that are around genome editing. So, you know, asking, will he apologize? What's he going to do now is maybe the wrong approach. Maybe instead, we need to think about discussing what are the times where maybe we should do editing or when we shouldn't, and that sort of thing. So, it's an ongoing question. As it stands, the US National Academy of Sciences and the UK Royal Society concluded that this technology is not ready for the kind of editing he did not for embryos destined to be implanted, and in 2021, the WHO advised against the use of it. So, the type of research he did on the CRISPR babies back in 2018, seems to be widely considered as not being ethical. But there are other kinds of genome editing, which will be going on. And as technology advances, there'll be more ethical things that we need to talk about and maybe we need to stop talking about He Jiankui.
Host: Shamini Bundell
That sounds like a good idea, and I'm sure as this sort of new technology is being developed, we're gonna’ have more opportunity to talk about what that is on the podcast, and then also talk about the ethical issues that comes along with it all. So, thank you, Nick, and listeners. If you want more on the stories, we'll have links in the show notes. And while you're there, you can also sign up to the Nature Briefing, and get more articles like these ones delivered straight to your email inbox.
Host: Nick Petrić Howe
That's all for this week. As always, you can follow us on Twitter, we're @naturepodcast, or you can send us an email to podcast@nature.com. I'm Nick Petrić Howe.
Host: Shamini Bundell
And I'm Shamini Bundell. Thanks very much for listening.