Science Friday - Physics Mysteries, Appendix and Parkinson’s, Paralysis Treatment. Nov 2, 2018, Part 2

Episode Date: November 2, 2018

Ever wondered why your dog’s back-and-forth shaking is so effective at getting you wet? Or how bugs, birds, and lizards can run across water—but we can’t? Or how about why cockroaches are so darn good at navigating in the dark? Those are just a few of the day-to-day mysteries answered in the new book How to Walk on Water and Climb Up Walls: Animal Movement and the Robots of the Future, by David Hu. Once upon a time, there was very little hope for patients paralyzed by a spinal cord injury. The prevailing wisdom was that unless you could regenerate neurons across the spinal region of the injury these patients would never walk again. Now researchers say that perspective is based on an outdated way of thinking about the role of the spinal cord in movement. A new technique that delivers an electrical signal directly to the spinal cord has given a handful of patients the ability to move again and, as reported in a new study out this week in the journal Nature, has allowed them to walk. You’ve probably heard that you don’t necessarily need your appendix, especially if you’ve had it removed. But the appendix does have a function and scientists are learning more about how it affects our health. The organ plays a role in regulating the immune system, microbiome, and even Parkinson’s disease. A misfolding in the protein called alpha-synuclein has been linked to the disease, and researchers found abnormal clumps of this protein in the appendix. This week, a team of scientists found more evidence for the link. Reporting in the journal Science Translational Medicine, the researchers found that, for Parkinson’s patients, there was a 3.6 year delay in onset of the disease for those who had an appendectomy. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hey there, podcast listeners, Ira here. You've probably heard me say this before, but it is so important I need to say it again. If every one of our two million listeners gave Science Friday just $1 each year, we would never have to ask for money to support our programs. Can you imagine that? One buck a year. Well, you can't blame a geek for dreaming. So if you have a dollar to spare, or maybe 20, please consider support you.

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But first, once upon a time, there was very little hope that patients paralyzed by a spinal cord injury would ever walk again. Their prevailing wisdom was that unless you could regenerate neurons across the spinal injury, reestablishing a connection between the brain and the spinal cord, these patients would never walk. Well, thankfully, new research is changing that outlook. A new technique that delivers an electrical signal directly to the spinal cord has given a handful of patients the ability to not only move again, and as reported in journals Nature and Nature Neuroscience this week, it even allowed them to walk. Dr. Susan Harkama, a neuroscientist at the Kentucky Spinal Code Injury Research Center at the University of Louisville, was the first to use this technique on patients with paralysis.

and she joins us now to talk about it. And just to be... Gilles, she was not involved in this week's studies. Welcome to Science Friday. Thanks for having me. I'm really happy to be here. Oh, we're so happy to have you. Thank you.

Tell us how this technique works. How is the electrical stimulation being applied? Well, there's an electrode about the size of your pinky, but much thinner, that's placed in the lowest part of your spinal cord where circuitry exists that we now understand exists, that has been known for over 100 years in all other species that has a significant level of control over locomotion, which in our case is walking. So the electrodes placed over there, and then it's connected to a small battery and stimulator pack that's placed close to the skin, and then you can control it through the skin in that way.

So you place it below where the breakage occurred, the injury occurred? This is not placed across the injury, at all. So what's happening here is that, and what our research team has been studying for 25 years is how sophisticated is the human spinal circuitry. And I think what these results and the results that our group and the Mayo Group published in just recently as well shows that the human spinal cordial. circuitry is very sophisticated, and if you want to think of it, has a mind of its own. And that's how this is working. But it's amenable to being manipulated, it sounds like also. Well, yeah, so as it turns out, the spinal circuitry has intrinsic circuits that are ready

to control movement. And when someone has a spinal cord injury, as devastating as that is, the entire spinal cord actually isn't destroyed. Only where the bone is broken, do the neurons die. And unfortunately, that's thousands of neurons. However, there are millions more neurons below the injury that are alive, healthy, communicating with each other and under the right conditions can function. And so, yeah, sorry, go ahead. No, this is very interesting. Go ahead. Yeah, so what the circuitry expects is all this information from the environment about where your legs are in space, and so your spinal cord knows every second of every day what your body's doing.

And so after the spinal cord injury, all that circuitry is still healthy and alive, but you're sitting in a wheelchair that's taken away. So what has been done is you take the stimulator, and there's something called the central state of excitability. It's a scientific term, but you use that stimulator to sort of rejuvenate those circuits, and then you start retraining it with the information it's used to having. And so that's really the working theory behind what's going on. And so you're saying that there are, even though we talk about the spine being cut,

there are still millions of viable, healthy live neurons there. That's right, in every injury below the injury. Every injury. So every injury. No matter how severe that injury is at the site, there's millions of healthy neurons below that injury. Why did we not know that before? So, well, the reason is because there's long been a controversy that with humans,

because our miraculous brain must control everything. So regardless of that healthy spinal cord, unless we regenerated the lost neurons across the injury, there was nothing that we could do. So that's what our team's been looking at. We've been challenging that hypothesis for the last 25 years. And so we focused on a little bit differently than the Swiss study. We focused on looking at motor completes. So motor complete are those that by all international standards,

all clinical current standards, would have no viable cells across the injury level. And so we and the Mayo Clinic in the same week in Nature, us in New England Journal of Medicine, published showing people could also walk with the stimulator overground. And to us, that was that proof of principle that it was the circuitry. So you could try to mimic and create sophisticated circuitry that could control the muscles? Yeah, so there's actually three other individuals reported who have motor complete injury, who are walking overground as well. And so that demonstrated that circuitry.

And so now the Swiss study has followed up with three other individuals. Now they are incomplete, and so there's a distinction between the two populations still very, very important, and they have fibers, motor fibers that were known to be there that go all the way down to the spinal cord. Now, what's really important about that is it shows this plasticity, because all of these people had been injured for years, and by all medical standards, so for those patients in the Swiss study, they had reached all recovery that was ever thought possible. So again, by taking this human circuitry, rejuvenating it, if you will, training it, stimulated it in a sophisticated way,

they were able to drive much more motor recovery in these individuals. So I think if you take the studies collectively, what it tells us is that there's much more we can do for people with spinal cord injury than we ever thought we could do. A listener, Donald tweets a very, very incisive question. He says, fascinating. Would this also work for quadriplegic patients? Yes, in fact, our, so one of the two people that we showed was a quadriplegic. So again, theoretically, it does not matter where the injury is because you are functioning below the injury with these healthy millions of neurons of the spinal circuitry. Now, let me say that with caution because it's going to take, you know, of course, large cohort studies, large trials, a lot to understand who can best is best,

going to recover, how much people are going to recover. There's so many clinical factors that are going to go into this. But I think what's important about this is the proof of principle. A couple things that I think we've learned from this scientifically and clinically. First of all, those people that we thought remote or complete are completely paralyzed are not. Secondly, people who have had injuries for many years may have the potential to recover. And there's a whole approach to recovery paralysis that we have not tapped into. So there's a lot of research to be done. There's, you know, a lot of discoveries to be had, but I think there's, I would suggest there's enough evidence to invest in this and to move it forward.

You know, all the people listening who know people with injuries are injured themselves are going to say, oh, boy, I'm very hopeful now. Are they getting their hopes up too much? Well, I mean, I think that's always a difficult question. But what I would really say, is that you've now got three independent places that have taken individuals who, from all medical standards, were not expected to improve their function. And, in fact, in other areas of our research that we've also published recently, we've seen improvements in other secondary consequences, such as cardiovascular dysfunction and bladder. So what I would say is that there are many opportunities here for incremental improvements in health and function for people with spinal cord injury and that this is an amazing time for research and changes in clinical care for people with spinal cord injury.

I think there is a real opportunity. How fast that goes and how that moves forward is going to depend on a lot of things, resources, stakeholders input. And there's going to have to be a significant change in the technology to be designated specific for this use, for use with spinal cord injury. Because we use this experimentally off the shelf that's used for pain and other people. So there's a lot of work to be done. But I think, you know, these papers were in, you know, high-level journals, you know, peer-reviewed journals. I think that these results are very strong, and so I think it's a really important time in this field. You're saying, you know, we've underestimated the plasticity of our nervous system.

Could it also be underestimating the plasticity of our brain steel, maybe in stroke or Alzheimer's or something else like that? Well, I think that the plasticity of the brain has been well accepted. What's not been accepted is the sophistication of the spinal circuitry and the potential of plasticity also of the spinal circuitry. And that how they're integrated. So yes, I agree. And the other thing is when you think about a brain injury or a stroke,

you think we have to repair the brain. But I think also that taking this approach of retraining the circuitry to function again with what is left of the nerve system, working around what's still there. It doesn't mean that repair and restoration, you know, repair and regeneration strategies aren't as important as well. But this is an approach that we have not yet taken advantage of. Well, we hope to hear more about it and about your work, Dr. Harkama. Thank you for explaining all of this to us.

I appreciate it. Quite illuminating. Dr. Susan Harkima, neuroscientist at the Kentucky Spinal Court Injury Research Center at the University of Louisville. There are probably a lot of view listening. that have your appendix removed. Moving on to another topic, not elegantly, of course, but we're going to talk about that next,

because just as, you know, this is surprising news to hear about spinal cord injury. There's a new study that shows your appendix can affect your risk for Parkinson's disease. We've got all kinds of new stuff this hour. It's after the break. We'll find out more about that. Stay with us.

This is Science Friday. I'm Ira Flato. You've probably heard that you don't need your appendix. Who hasn't heard that? You can have your appendix out. It's just a vestigial organ. It doesn't do much for us anyhow. So, especially if you've had it taken out.

Well, that may not be entirely true. There's evidence that the appendix plays a role in regulating our immune system, our microbiome, and even Parkinson's disease. New research shows that a key protein linked to the development of Parkinson's disease is found in the appendix. Scientists found that in Parkinson's patients who'd had an appendectomy, onset of the disease was delayed by nearly four years. These findings were published in the journal Science Translational Medicine. So how does the appendix connect to a movement disorder like Parkinson's and should be rethinking our appendix?

Vivian LeBrie is an author on that study. She's also an assistant professor of neuroscience at Van Andell Research Institute in Grand Rapids, Michigan. Welcome to Science Friday. Thank you. We've often heard that we didn't really need our appendix, right? Yeah, normally when you think of the appendix, you think of this useless organ. It's attached to the large intestine, and an appendectomy is a very common surgical practice. But as it turns out, the appendix does have a function in our bodies. It plays a role in the immune system. It regulates and it regulates the microbiome. So we need to do it. We need to know that inflammation has been linked to Parkinson's disease, and there's changes in the microbiome

in Parkinson's patients. And the microbiome, the gut bacteria of your intestine, can regulate brain health. So this small tissue is actually an immune tissue, which samples and monitors pathogens, and will raise immune responses, and is a storage house for the gut bacteria in your intestine. And so does the gut bacteria travel then up to your brain from the appendix? No, the gut bacteria will communicate with the immune system. It can also modulate the firing of nerve cells in the GI track. Your study found that in people who had their appendix removed, their risk was 20% lower compared to those who still had their appendix.

What do you think is happening there? Right. So in our study, we looked at big medical history data sets, And we found when we looked at 1.6 million people that there was a lowered risk for Parkinson's disease. In fact, the risk was lowered after an appendectomy by nearly 20%. But the appendectomy had to have happened in early life. So an appendectomy occurring 20 or more years before the onset of Parkinson's symptoms. So most people have an appendectomy in their 20s.

And then if Parkinson's were to develop, that would be in their early 60s. And so what we think is happening is that the appendix could be involved in the early events or even in the triggering of changes that could lead to Parkinson's disease. And that's because when we looked inside the appendices of healthy individuals, as well as eventually we studied the appendix of Parkinson's patients, we found an abundance of this clumped protein called alpha-synuclin. Now, alpha-synuclin is a protein that makes up the hallmark pathology of Parkinson's disease, Louie bodies, they're called, and these are found in the Parkinson's brain. And what we saw in the appendix of even in healthy people, that the clumped

protein alpha-sineuclin was present in the nerve cells and very much resembled the protein that you would find in Louis bodies in the Parkinson's brain. So what we think might be happening is that if the clump protein were to accumulate in excess and potentially have escape and travel up nerves that connect the GI tract to the brain, this could have disaster. risk consequences that could lead to eventually Parkinson's disease. It's fascinating. Are we recommending people then have appendectomies or not have them? One thing we're definitely not recommending is for people to go out and have preventative

appendectomies. We're also not suggesting that just because you have an appendix, you're going to get Parkinson's disease. But what we are saying is that the human appendix, even under normal circumstances, contains an abundance of this clump protein we associate with. with Parkinson's disease. So what distinguishes a Parkinson's patient from a healthy individual's is not the presence or absence of this clump protein, as we once thought, but perhaps a difference in the

ability to manage this pathology. So if in some people it were to accumulate in excess and travel up nerves that connect the GI tract to the brain, this could cause Parkinson's disease. If there is a definite connection or a strong connection, why? Is the percentage is not different, much higher percentages, instead of a 20% or 40%, something like that, why not 70, 80%. So Parkinson's disease is really an umbrella term for a disorder that involves multiple trigger sites. So for some people, I may start in the GI track,

and so there's evidence that the pathology associated with Parkinson's disease is seen in patients even years before the onset of motor symptoms. We also know that this pathology, this clump protein called Alpha's Ninochlin, is a protein that doesn't like to stay put. It's able to travel between neurons and neurons, nerve cells to nerve cells. And there's a nerve of fiber that connects, or nerves that connect the GI tract to the brain. It's called the vagal nerve. It's not the longest nerve in the body, but certainly a very long one. And we know that this protein can travel up this nerve and enter the brain and see it and spread from there.

For other individuals, the disease might start in the brain or elsewhere in the body. So Parkinson's disease, you know, encompasses multiple trigger sites. What's surprising is that some of those trigger sites might be outside of the brain. That is surprising, isn't it? Mm-hmm. Yeah. I mean, it's amazing. I'm trying to digest, so to speak, digest it.

We talk a lot about the microbiome on Science Friday. So we're sort of connecting it in with the microbiome. with the microbiome here, are we not? Right. So the microbiome in Parkinson's patients is known to be different. And those changes are still being described. But these differences seem to be, you know, differences in the microbiome can affect brain health. So it can affect the singling of nerves. It can, it's also known to change mood like anxiety and depressive symptoms. So there's other symptoms in Parkinson's disease, such as the non-morty symptoms, which do involve things.

depression. So you could have the microbiome regulating the neurogenital aspects, but also the cognitive or the anxiety symptoms as well and the depressive symptoms. So the microbiome is a complex thing. It's made up of different bacteria. And if the bacteria ecology were to shift to, say, a pro-inflammatory microbiome, and if that pro-inflammatory microbiome were to be housed in, say, the appendix, which helps regulate the gut bacteria in the rest of the GI tract, that could have disastrous consequences. The other thing that I want to mention is that the appendix is really important in the immune system, and so inflammation has also been tied in to Parkinson's disease,

inflammation specifically in the GI track and in the brain. And they know that if there's a lowered risk that's associated with Parkinson's disease in people that take a compound that reduces GI-track inflammation, We also know that different illnesses like Crohn's disease have a greater risk. This is a disease that involves GI tract inflammation. These individuals have a greater risk for developing Parkinson's disease. So there seems to be connections related to the immune system, the microbiome, and this clump protein called alpha cyanuclin, and its ability to seed and spread.

So what would you like to know now that you know this? Where do you go from here? Well, we were really surprised to find the pathology associated with Parkinson's disease, this clump protein alpha cyanuclin, in the appendixes of healthy individuals. And we looked at young individuals under the age of 20, older individuals, inflamed or non-inflamed. It was in everybody. And so that made us realize that Parkinson's disease wasn't defined by this pathology. It's very normal to be present in the appendices of people. But it's very, if that pathology were to travel to the brain and enter the brain, that has neurotoxic effects.

So location is everything. Clump protein, alpha-signucline in the appendix, very normal. Clump protein of alpha-signucline in the brain, neurotoxic. And so what we think is going on is that there's possibly a difference in ability to manage this pathology between healthy individuals and people who will go on to develop Parkinson's disease. And what we want to get down to is those molecular mechanisms that will distinguish. a healthy individual from a Parkinson's person, and that will help us develop markers and perhaps improve the targets and develop new treatments for this illness. That would involve treatments that would be very exciting because they would target the GI track instead of, you know, the traditional

treatments which are focused on things that are happening in the brain. So it opens up a whole new avenue of therapies for Parkinson's disease. Very interesting. We had a tweet from Lisa who said, you know, what about, you know, the effects of diet? Could diet then, because we're talking about that GI area, and we're talking about the appendix, also play a role here? Well, I think that diet and inflammation do tie into each other. So good eating, good sleeping, exercise, all these things are beneficial to the immune system. And so anything that can kind of help,

dampen down inflammation in the area that the GI track. Now remember the GI track has an abundance of nerve cells. It's sometimes called the second brain because it has so many neurons that it's more than even the spinal cord, not as much as the brain, but more than the spinal cord. So if we were to turn down inflammation, which has a close communication with nerve cells in the GI track, that could only be a benefit. And so things like diet and exercise and good sleep are ways of doing that. Dr. LaBrie, thank you for taking time to be with us today. Fascinating.

Thank you. My pleasure. Vivian Lebris is an assistant professor of neuroscience at the Van Andal Research Institute in Grand Rapids, Michigan. Next up, ever wondered why your dogs back and forth shaking is so effective in getting you soaked? Oh, yeah. How bugs and birds and lizards they can run across the water without falling in. or how cockroaches are so darn good at navigating in the dark. I've noticed that many times. And they're kind of questions, right?

They leave you scratching your head that you may not have known you wanted to know the answer to until you, you know, but once you ponder them a little more, you think, yeah, how is that possible? I've thought about this all the time. Well, well, we're all in luck because all of these questions and more are answered in my next guest book, how to walk on water and climb up walls, animal movement, and the robots of the future. David, who is the author? He's a mathematician, professor of mechanical engineering and biology at Georgia Tech in Atlanta, and we have an excerpt up there at ScienceFriety.com slash walk on water.

Welcome back, David. Hi, Ira. It's great to be back. Nice to have you back. I want to send out a question to our listeners and ask them if there's anything in their day-to-day life that might make for a good physics experience. A mundane question that might have a fascinating answer. We'd like to hear from you. 844-724-8255-8-4-Sai Talk.

What do you wonder about nature that you want to know about, and maybe you can do an experiment to figure out how to do that? Because that's what you do all three. You just wonder about stuff around you, don't you, do? Yeah, everyday world is a great window into evolutionary history. You know, all the animals around us, all the people around us, They do the same functions that, you know, all animals have done from small all the way up to large. They give us a really good idea of, like, you know, what is like to be really small or really big or really hairy.

I'm Ira Flato. This is Science Friday from WNYC Studios. You've investigated something called the wet dog shake, and that's not a dance move I'm talking about. Tell us about that. Maybe it is a dance move. It would be very difficult one. Well, yeah, when I first met my wife, on our very first date, she brought this poodle that I basically had to learn to get to know and appease the next few years. And it was the first time I'd spend her time around dogs, and I noticed it was really, really good at shaking off water or any stickers I put on it. I mean, it was really, really fast, and I'd never seen it before.

So I decided to high-speed film it. And what I saw in the high speed of film just amazed me. I don't know if you've seen a dog shaking of water under slow-mo, but they can generate huge amount of forces. They generate basically 12 times Earth's gravity. It's the same force that a Formula F-1 race car takes when it takes around a curve. It's basically the limits of what the human being can take. There's this guy named Colonel John Stapp,

a scientist who tried to test the limits of human acceleration. and he strapped himself to a rocket sled and then slammed on the brakes. And he found out at about 10 Gs, 10 times Earth's gravity, your body's fine, but your eyeballs start detaching from the retinas. And so actually all these animals that are doing this wet dog shake, they're pushing the envelope of what their bodies can take. They're closing their eyes shut really tightly just don't get their eyeballs sort of attaching. And it's amazing how much water they actually get rid of, isn't it?

Yeah, we did these experiments. we weighed all sorts of animals before and after they shook off water. And in a single second, your average dog can remove 90% of its water. For a 60-pound laboratory retriever, that's about a pound of water. And it removes it all in a second. And that's comparable to what your laundry machines do in about an hour. That's amazing. If you stand, you know, stood next to dogs, you understand how much water that is.

They're really good at getting the water back on you, yeah. Now, I know one of your first projects you studied, you studied how water strider bugs, these great bogs, they can walk on water, you see them on lakes all the time, how they can paddle through the water without having oars on their feet. How do they do that? Yeah, that's right. I mean, imagine if you're going for a crew race, you know, a rowboat race, and someone handed you these long, just chopsticks and said, go row your boat. And that's basically what these water starters do. They row without any blades just with these long, spindly legs. Each of these legs is about a width of a human hair.

But what allows them to work is that they're covered in hair. These water strutters, they're the hairiest animals on earth. I mean, I've been to some swimming pools. I think I've seen the hairiest things on earth. But, no, it's these water striders. They've got about 10,000 hairs per square millimeter. And it's such a, you know, such a corrugated surface that water can't actually penetrate it. So when they're standing on water, they're actually standing on a cushion of air

that's trapped within their hairs. From beneath, they just look like a pin cushion. And because they're just floating on air, you can blow them and they just glide like the water's ice. Have we been able to mimic that at all? Yes. Well, when I was in grad school, we built this machine called RoboStreter. It's this device about a big as my hand weighs a third of a gram. and it's made with hydrophobic aluminum and steel, and it can actually support its weight on the water surface, like the water starter using surface tension. And it rose without getting wet.

It treats the water surface kind of like a saran wrap. It just deforms it, kind of massages it, and its oars don't actually break the surface. They just bend it, and it rose across the water. And since then, there's been lots more versions built. They're imagined to be sort of these cheap devices, maybe fueled by solar cells or fueled by electrolysis of water that you can spread out of the in the oceans,

and they'll just take data. Talking with David Who, author of How to Walk on Water and Climb Up Walls. We're going to take a break on number 844-4-4-7-24-8255. You can also tweet us at SciFry, things that you'd like to talk about, how animals do this stuff in the world, and David, he goes out and studies them all. We'll talk more with him after the break, so stay with us.

This is Science Friday. I'm Ira Flato talking about the physics phenomena of the animal world, the topic of the great new book, How to Walk on Water and Climb on Walls with mathematician David Hu of Georgia Tech. And we're looking for your questions. Anything that tickles your curiosity in your daily life, something that might be solved by creating an experiment. We're asking you to phone in 844-724. A255, and here's someone who I might be thinking like that. Sean in Cincinnati.

Hi, Sean. Welcome to Science Friday. Ira Glass. What a hoot. There you go. I love your show. Go ahead. Yes.

Well, this has been bothering me for about 25 years, and I can't understand how it is that a fly can land on a ceiling. David? How does a fly land on a ceiling? I'll have Ira Glass get back to you on that one. Dave, what do you think? Well, flies, ants, and a lot of insects, they have a couple ways to basically walk on walls or walk on the underside of ceilings. And a lot of these ways would be difficult for us, but there's actually new technologies that are making it possible. So there are actually people that have built devices that are allowing them to climb on glass buildings like geckos and flies.

So there's a couple ways. the flies do it. If you zoom in, imagine zooming in down to that little fly leg. First, they've got this little thing called an aerolium. These are a small balloon that pops up every time the fly puts its foot down, and on this balloon is a really thin layer of fluid. It's kind of like a glue. In fact, if you actually look really closely at your fly, and they've done this for ants, you'll see its footsteps. You'll see a trail of little drops of goo. that it's left behind. It's the surface tension of that goo that allows it to stick.

The same force that allows drops to cling to your ceiling or to your car windshield window. That's the same force that supports the fly weight because it's so light. So that's one way that the flies do it. They also have a series of hairs. The same hairs that the gecko has. There's an example of what's called convergent evolution

that two species they don't look at all like one's way bigger. In fact, one each the other. They have very hairy feet. And the gecko's hairs, for example, aren't just hairs. There's like Christmas trees with Christmas trees on the tips of the Christmas trees. I mean, they have a series of progressions that get more and more hairy. And it provides this really large surface area that's really close to that your ceiling.

That provides a huge what's called VanderWals, force. You don't even feel it. When you pick up things, there's always a vanderwal's force, intermolecular force between two objects. It's what allows pollen to kind of stick to your clothes. But when you have a really large surface area, it's enough to actually support the weight of these insects. And these engineers at Stanford have actually built versions of this, where they've engineered arrays of hairs and made sure that they can hold on to things. remember there was a big controversy about this. In Colbert report a while back, people were saying Spider-Man doesn't exist because people had shown that if you try to scale up Spider-Man's,

sorry, not Spider-Man, a spider's legs, it wouldn't be able to support the weight of human. And that's because when you have a large array of these hairs, they don't act as good as just one hair multiplied many times. They start to lose their effect because the weight support is not equally applied to all these hairs. There's some parts that get too much weight, and those hairs peel off. While these engineers have found a way to basically create these little kind of yokes,

like small, these things that are in front of cattle, there's ways to basically equally distribute weight. They applied these things to these hairs, and they're allowed to basically make these handheld plates that allowed a student to actually climb up a glass building, like a spider. Yeah, yeah. Our number 844-724-8255.

Let's go to Dave. Dave in Cheyenne, Wyoming has an idea for an experiment, right, Dave? Yeah, I do. I have always been interested ever since I saw it with the levitating frog in the high-intensity magnetic field. Yes, go ahead. And my experiment is I wonder if that could be done with human beings. Levitating a human being in a high-intensity magnetic field. What interesting idea?

What do you think, David? So that's used this idea called paramagnetism, where organic things, like things made in water, can actually become like magnets. The big issue was that that magnetic field, which was, I think, in Europe, was only big enough for strawberries and a frog. They still haven't big.

made one that's strong enough to levitate a person. But the frog, so that guy who won an Andre Geim, he's a fellow Ignobeau Prize winner, and he tells me that the frog was fine, so it's possible a human could do it too, but they would need a much bigger, much bigger magnet. That was the most expensive magnet they had, and it was just big enough for a frog. Or a really tiny human. Somewhere Galvani is laughing about that experiment. I want you to recount for us because you have a great story in your book.

You open your book about a story about you as a new father. Let me put it that way. An event that happened to you as a new father that launched into an investigation of yours. Did I give you enough information? Yeah, we can talk a little bit about what it's like to be urinated on. And so, yeah, when you change kid diapers, sometimes they play games, and one of their games they play is, let's wait the diapers off to urinate. And there was a time that happened, and I was kind of shocked.

And one of the things I was shocked by was how long it takes little kids to urinate. I mean, any parent that's waiting for a kid in the bathroom, you think if you're smaller, everything should be faster, but no. Urination takes about the same amount of time. And for my measurements, it was about 21 seconds for about a 10-pound kid. and those are comparable to my own measurements of my own urination time. And it just struck me because if you're 10 times smaller, you should have 10 times less urine.

Urines are a byproduct of the blood, urea, and the bladder should be 10 times smaller if you're smaller. So I couldn't wrap my head around it. And, you know, I got a PhD in fluid mechanics. I couldn't understand why it takes the same amount of time if you're smaller. So I said some undergraduates, One of them who's now a professional urologist, which I'm super, he just lifelong learning. Just couldn't stop.

Couldn't stop it. Couldn't stop the fun. And they went to the zoo, and I tell them, you know, bring this stopwatch and bring this dirty old bucket and this camera. And, you know, don't come back until you've taken all the animal urination videos and measured all the urination volumes of every animal in the zoo. And they took me seriously. And they actually did come back in a few weeks. They smelled disgusting and splattered in urine. and they told me the very worst was the rhino.

They were kind of traumatized by the rhino. But I said, just tell me one data point, and then I'll know everything I need to know. And that's the elephant. Just tell me how the elephant goes to the bathroom. And they said, the elephant doesn't listen to anything they tell it to do. It just wakes up in the morning. But when it does wake up, it takes a long urine.

And they put this kitchen garbage can. It's about 20 liters, you know, very large garbage. which can last for a week. And it fills the entire can. And I said, how long does it take? And they said, well, that bladder is about 100 times as big as your wife's dog, and it takes about 21 seconds. And I said, that's the most amazing discovery I've ever made.

That's pretty much this is the pinnacle of my career. And it turns out it's because they have this long pipe in their body. So doctors and veterinarians, have long known that in the body there's this thing called the urethra. My kids call it the pee-pipe. And I have to tell my kids, you know, boys have the pee-pipe and girls have a pee-pipe. It's just, you know, in different places. And it actually has the same aspect ratio. The length of width is the same for like mice all the way to elephants. And to put it put in perspective when an elephant urinates, it uses a female elephant uses a pee-pipe that's about

a meter long and about the width of my fist. So if you imagine that pee-pie pie is like a highway, you've got, you know, we wish we had this in Atlanta. We'd have like 20 lanes for the urine to come down. And, moreover, the length of that pipe, it uses this effect that dates back to the 1850s called Bernoulli's Law, where basically if you've got a long pipe underneath a sort of a vessel, that pipe can actually amplify the force of gravity and increase the speed of the urine. So much that when an elephant urinates, it's like five showerheads going on at once.

Wow. You've given us more to talk about tonight over a beer than any time in the recent past on size flight. Yeah, you would get really clean from five showerheads, but not five urine showerheads. That would be less clean. Yeah, we'll quote you on that. While we're on the topic, while we're talking about wet things and on the topic of water, there's a chapter about another question I never knew I had until I read it in your book. And that is, how do mosquitoes fly through the rain?

You know, I mean, if it's raining really hard and tiny little mosquito, why doesn't get pummeled and knocked their way and smashed by all that water? A woman would think that with the mass of water, it should be devastating for them, but not so. Yeah, it should be devastating. And if you, you know, take a picture of a mosquito in a rainstorm, you'll see this water drop. They're about, you know, the same size, but the mosquitoes doesn't, you know, it's long, gangly legs. So the water drop actually weighs 50 times as much as a storm.

mosquito. It's like you getting hit with a Volkswagen Beetle. It's a huge, huge difference in weight. But, you know, that's the amazing thing about nature. It's taken advantage of this, you know, huge David and Goliath story. And it's taken advantage of the mosquitoes really lightweight. And this is how it does it. Like when you go in a rainstorm, you stick out your hand, and water, a raindrop hit your hand and splashes. And you can feel it. It's a pretty, it's a hard force. And the reason the force is so high is because you're ricocheting the raindrop. You're actually throwing it back up in the air. It's splashing because it's hitting your hand.

But when raindrops hit mosquitoes, they don't splash. That's the thing we discovered in the high-speed film. They just keep on going. And so if you don't actually, this is kind of a Zen thing. If you don't slow down the drop, if you don't resist the drop, you don't get that much force. And so because you're not sort of exploding, the drop, you don't get that much force. And the mosquitoes, they just go along for the ride, sort of acts as like a stowaway on this drop.

I mean, they're so hydrophobic. They'll eventually sort of split off, but they don't resist the force, and they just survive that way. I'm Ira Flato. This is Science Friday from WNYC Studios. Talking with David Who, author of the new book, How to Walk on Water and Climb on Walls. Let's see if we can get a phone call in before we have to go. Let's go to Barb in Seattle. Hi, Barb.

Hi. Go ahead. Okay, so my question, going back to the fly theme that we had earlier, is those annoying little fruit flies, like in your kitchen, little tiny things, and you have a great big hand, and you go to swap them, and they seem to magically transport to someplace else. Why can we not hit those little bitty things? How do they maneuver so quickly and so agilely that we can't get them?

Good question. Yeah, David. Well, Sally, if you, if so, that has an evolved response for millions of years. I mean, those flies are tasty little protein, fatty treats. So if an animal could really get them, they would have. And the way they do it is all preparation. So if you actually, the fly has excellent vision. They can see what's called looming objects.

So your hand, as it's coming down from far away, it's increasing in size. And the flies can see that. And even before you're even close, they see this looming object, and they actually start preparing, far, like even inches, foot before your hand is even close. And what they do is they actually, Michael Dissan has filmed this at Caltech. They move their middle legs. They've got six legs. They move it in response, so they're actually – they feel the direction of this looming object,

and they move their legs in response, so they're ready to jump in the opposite direction as soon as possible. And they do all this without the brain. It's basically all sort of autonomous. It's just an instinct for them. So just from this Lumen response, they know what direction is coming from. And by the time your hand has even gotten close, they've prepared just take this catapult-like leap. And they just basically leap in the opposite direction before you even touch them. Before we go, I want to touch on a serious turn that your book takes at the end when you talk about how your research has been targeted by politicians for being so-called wasteful science.

Tell us about that. That's right. About two years ago, my university told me to turn on the TV show Fox and Friends, and there's this huge game show where they put all the names of these scientific studies. And I found out that I was on this list of the most wasteful scientists for the entire country. And not only that, but I was on the list three times, which made me responsible for 15% of the entire country, which I was kind of proud of because I'm just one person.

And I thought, that's pretty good this year. This I can go for 30% next year. Basically, they were saying that, and they don't just target me. They've targeted a lot of people who study animal movement. Sheila Paddock's Fight Club for Shrimp, basically, people who are studying how shrimp can, you know, use their fists to break open mollusks. Treadmills for shrimp. People that are basically studying animals and how they move, we're sort of easy prey for. these attacks against science.

You write that the concept of waste is based on the notion of a limited gas tank and a single known destination. People expect science is to save gas as they go from A to B, but the real power of science is to take us to destinations that we have never been to. That's right. It's hard for people who are not involved in science to know about that failure is an option in science. You know, making mistakes and failing is something you really welcome. as opposed to other places in life. Yeah, and the study of these animals, these animals are, I mean, for example, the people have been calling,

how do bugs escape a fly swatter? I mean, these animals are doing things that our machines are still not capable of doing. And this is important because we're hoping that our robots, I mean, these robots are trapped in factory floors. They're doing repetitive tasks. We were hoping they can actually face the great outdoors, places where there's, you know, leaves and wind,

and water. And to do that, they're going to have to become a lot more animal-like. They're going to have to learn to deal with different terrain, sand, water, rainstorms. We're going to have to, and the only way we can understand how to design those kind of things is to look at, you know, the things around us and how they're doing it. Well, you do a very good. And they're two of our first step. Yeah, and you do a very good job of that in your book, How to Walk on Water and Climb Up Walls,

animal movement and the Robots of the Future. Thank you, David. It's a great read. Thanks. Thanks for joining us. David Hu is a professor of mechanical engineering and biology at Georgia Tech in Atlanta, and we have an excerpt up on our website at ScienceFriety.com slash walk on water. B.J. Leatherman composed our theme music, and of course you can listen to our program.

Any way you like to listen to podcasts, we're there, and you can also ask your smart speaker to play Science Friday whenever you want. So every day now is Science Friday. Have a great weekend. I'm Ira Flato. Get out there and vote in New York.