Quirks and Quarks - How dandelion seeds take flight, and more…

Episode Date: May 15, 2026

In a study inspired by a field of dandelions, researchers wanted to know why, when you blow on a dandelion seed head, only the seeds closest to you take flight. They found that a dimple in the seed heads where the seed attaches is larger on one side than the other, and that the seeds consistently broke off from the smaller side of that dimple. Once they take flight, each dandelion seed uses its unique shape to catch a ride on the wind.PLUS: Infrasound, not ghosts, may be why old buildings give us the heebie-jeebiesThese arms are made for lovin'. How male octopuses find their matesFrom the archives: Donald Johanson on the discovery of 'Lucy,' our missing linkVirtual hearts help doctors fix patients’ life-threatening irregular heart beatsQuirks Question: What’s the benefit for trees being evergreen?

If you sold somebody a loaded gun who you knew was in a vulnerable state and they shot themselves. I think it is murder. Just because you're using the internet doesn't mean you get away with murder. I'm Damon Fairless, host of Hunting Warhead. This season, I take you inside the business of suicide, and the places desperate people go when they can't find what they need in the real world. Hunting the Suicide Salesman. Available now, wherever you get your podcasts.

This is a CBC podcast. Hi, I'm Bob McDonald. Welcome to Quirks and Quarks. On this week's show, how inaudible sounds from old pipes in an abandoned house, not poltergeis, maybe what's leaving you spooked.

They might feel like there's some tension in their chest or the hair on the back of their neck goes up. And I think we might have at least a partial explanation for why that might be, and it's not ghosts. And an accidental discovery of how octopuses find mates in the deep dark ocean. What we didn't expect was actually that the male put this specialized arm through one of these holes, was able to identify the female and initiate mating.

Plus, the physics of dandelion seeds, virtual hearts for life-saving treatment, a question about conifers, and an archival interview with the paleoanthropologist who unearthed Lucy. All this today on Quarks and Quarks. Have you ever walked through an old building? and something just feels off, eerie, unsettling? Now, your first instinct might be to assume that the building is haunted by paranormal spirits,

but that explanation doesn't sit right with Dr. Rodney Schmaltz. As a psychologist, he wanted to investigate whether these seemingly paranormal experiences might be more scientific than supernatural. Now, in new research, he's found a potential culprit. And no, it's not a poltergeist. He suspects that low-frequency sound waves below our range of hearing, called infrasound, are actually giving us the hebi-g-bees. Dr. Schmaltz is a professor in the Department of Psychology at McEwen University in Edmonton.

Hello, and welcome to Quarks and Quarks. It's a pleasure to be here. Well, it's been a while since I've been in a haunted house, so take me through the feelings that people typically experience that you wanted to investigate. often people go into a haunted house, they report feeling just this general sense of unease or irritation, and they might feel like there's some tension in their chest or the hair on the back of their neck goes up. And I think we might have at least a partial explanation for why that might be, and it's not ghosts. And it's not just the power of suggestion because they were told it was haunted? The power of suggestion definitely plays a role.

And we think on top of that, when people are exposed to infrasound, especially we're, when they expect to see something spooky or a ghost, that might be driving what people are actually experiencing rather than any kind of paranormal activity. Well, why did you want to choose infrasound as a potential source of some of these paranormal experiences? Well, infrasound can be found in older buildings. It's things like low rumbling pipes, old boilers, ventilation system,

things like that. So if you think about a lot of hauntings, they tend to be reported in old buildings or old castles if you're in the UK, whatever it might be. And we were wondering if we could at least partially explain a piece of the puzzle by looking at infrasound. So what exactly is infrasound? Infrasound is a low frequency sound below 20 hertz. We can't consciously hear it, but we can feel it. The way I like to think about it is imagine you go to a concert. There's a lot of bass, the hair on the back. Your neck goes up, your chest

gets a little bit tight, but you know what it is. It's from the music. Now imagine you had that experience, maybe at a bit of a lower level, but a very similar physiological experience, but there's no sound. And imagine that you're in an old building. You've been told it's haunted and you have this feeling. It's quite reasonable then to think, maybe there's a haunting here. Maybe I've experienced a ghost when, in fact, what you very likely experienced was an old boiler. Now, is it just old buildings that do this, or can infrasound be created in other environments?

It can be created by things like traffic, subways, uh, low. machinery can do it. For the study we conduct in our lab, we actually built some speakers. Commercial speakers don't really generate infrasound. Why would they? People can't really hear it. So we built speakers for the study, but it is kind of all around us. Well, how did you test this theory? That infrasound could be the source of people's eerie feelings. We've conducted a few studies. Where we started was based on a study called the Haunt Project. And this was conducted in the UK. And what researchers did is they brought, brought people into this lab, and it was basically an apartment, and they had white sheets everywhere,

and they exposed people to infrasound and some other things in dim lighting. And people walked around for around 50 minutes or so, and they found that the infrasound didn't have any impact. So what we wondered is maybe you need a bit of that fear response first or something. So rather than just walking around a dimly lit building, maybe if there's something that's already a bit scary or the expectation of something scary, that would have the impact. So we did some research in Dedmonton, which is a commercial haunted house here in Eminton, and it's fantastic. It's Hollywood level of special effects.

We did this in the off hours, very scary place, and we had infrasound playing or not as people went through it. We had a number of measures. We had a few mechanical difficulties with our equipment on this one, but we did find that people went through the haunted house faster when infrasound was on than when it was off. That leads us to this study. We decided to bring it into the lab so we would have a more controlled environment. And what we did is we brought people into the lab and they listened to either ambient, scary sounding music, kind of like what you'd hear in the background of a horror film, or they listened to music that was relaxing and calming.

And they did this in the presence or absence of infrasound. So when they came into the lab, they were told they might be exposed to infrasound, but we didn't tell them until the study was complete whether or not it was actually on or off. What we found was that regardless of what type of music they listened to, cortisol levels went up. And cortisol is a hormone associated with stress. As well, general levels of irritation went up and people rated what they listened to as sadder and less interesting. And again, that's regardless of what type of music they were listening to. Wow. How did you test their cortisol levels? It was salivary tests.

So basically, we had people spit into a jar, a test tube, before they said. started, and then at the end of the study, they did it again, and that we did a pre-post comparison. Boy. So the infrasound really was having an effect. That's right. And we also asked people, before we revealed, whether or not they were exposed to infrasound, if they believed it was on.

And people performed basically a chance. They couldn't guess whether it was on or not. So they genuinely didn't consciously hear it, but it did have this physiological impact. So what does this tell you about what people might be experiencing in a spooky location? What's interesting about it is that when people go into these spooky locations, they actually are feeling something, which really shows that it's not maybe irrational to have this belief. Because if you think that something is haunted, you have these feelings. It's, again, fairly reasonable to attribute it then to, say, a ghost or a haunting. But if you know that it's infrasound, instead of going, this might be paranormal, you might say, I bet there's an old boiler or some low rumbling pipes in here.

I wonder if I can find them. So what about other sources of infrasound in buildings like, I don't know, maybe it has an old air conditioning system, an office building or something that has old equipment? Right. We looked at a five-minute exposure to infrasound, and we found these levels of irritation went up and the cortisol levels went up. So it could be that it's leading to more irritation, but we hesitate to go beyond the data. It might also be the case that people habituate to it. We just don't know. So we're interested in doing some follow-ups. We want to look at different exposure times, different frequency levels, different decibel levels. So there's still a lot of work to do. But we do know from this study that at least in this short exposure, that there's this physiological impact.

And again, people have that feeling of irritation. So if you have a bad day at work, maybe it's just because the furnace came on. Maybe. We don't know. But it's created by traffic, too. So we're not saying that this would explain why people are irritated in traffic. of course, but maybe it's a small piece of the puzzle, but again, we don't want to go beyond our data, but it would certainly be something interesting to look at.

If that's the case, do you think this disproves the existence of ghosts in haunted houses? No, we can't go that far, but I do think it gives us a small piece of the puzzle. Expectation is still a huge driver, and it could be that infrasound is a part of it, especially when it's coupled with that expectation. So, no, we're not disproving ghosts, but we are giving a piece. piece of the puzzle for at least some rational explanations and it well some of the hauntings some of the one last thing do you believe in ghosts i have not seen any evidence that leads me to believe that said if i did and i suspect i won't but if i did i would change my mind what i'm more

interested in is what people experience so i think when people report a haunting or a ghost they really are reporting a real experience and it's a meaningful experience I just think there's a rational explanation, and I find it fascinating to try to find out what that is. Dr. Schmaltz, thank you so much for your time. It's been a pleasure to be here. Dr. Rodney Schmaltz is a professor in the Department of Psychology at McEwen University in Edmonton. Whether it's using an app, a matchmaker, or even just chatting someone up at the bar, dating can be hard work. After all, as the saying goes, there are plenty of fish in the sea, and sometimes it can be hard to

recognize a good match when they first pass you by. And if it's challenging for humans, it's even more difficult for octopuses. Our many armed friends have to cover a lot of terrain to find potential mates, and they sometimes have to do it in the dark depths of the ocean, where it's not exactly easy to see who or what's around. Researchers at Harvard University have figured out how male octopuses feel their way to females using a special sensory organ in their arm. Dr. Nick Malono is a professor of molecular and cellular biology at Harvard University. He's a senior author on this paper. Hello and welcome back to our program. Hi, thank you. Now, before this study, what did we know about how octopuses find mates in the dark sea?

Well, we knew that the male uses a specialized arm called the hectorautilus to facilitate mating. And what they do is they use the hectoratolus to touch the female and then they They insert the hectoratolus into the female mantle or the body, and they feel around the internal organs, and then they find the oviduct, and then the male freezes, and it transfers a packet of sperm from its own mantle down the length of that arm until it meets the oviduct, and that's how fertilization happens. So it's a special arm, so it's one of the eight? Yep.

That's amazing. So how did you want to explore this further? So we kind of stumbled into this studies. The story was that postdoc in the lab wanted to see about mating in the lab. And so what we do is we get wildcaught octopuses. We put them in tanks in the lab and we individually house them because when octopuses are together, they're actually very aggressive because usually they're solitary animals that don't often interact. We first put two octopuses together in one tank, but we separated them by an opaque. barrier that they couldn't easily see through. And then we put three little holes in that barrier to allow the exchange of water, so maybe they would get a sense that another octopus is with them, and they would get used to it. So we put a male and female on either side, and then our plan was to remove that barrier after some amount of time and see if they would mate. What we didn't expect was actually that the male put this specialized arm, the hecticotolus, through one of these holes,

was able to identify the female and initiate mating. Wow. So you're saying that the octopus was able to find the female without actually seeing it? That's right. And we could even do it in pure darkness, and they could still find the female. And what was interesting was it was specific to females. So if we replaced the female with a male, the male would still explore, and then once it touched the other male, it would retract the arm and actually swim to the other side of the tank.

Well, tell me more about this arm. there's this sexually active arm. How does it actually detect things? So that's what we didn't know. And when we observed this interaction specifically with the female, we wondered if there was some kind of chemical coming from the female. And our idea was to think about what could be specific to the female. And we knew that the hectocotus not only has to identify female, but then it has to navigate the internal organs to find the oviduct. And so we looked at the oviduct and what kind of molecules it makes, and we found actually a very well-conserved steroid progesterone was made in the octopus ovaduct.

And when we learned that, we used it in two ways to ask about how the hectoros might interact with progesterone or the oviduct. And one was we applied progesterone to the hectocotolus and it responded on its own, even to that single molecule, which made us suspect that it might be sensory. And then the other thing that we did was we replaced the female octopus on the other side of that barrier with individual conical tubes. And in these tubes, we put individual molecules. And what was really shocking was that the male octopus put the hectocados through the hole and keep sort of exploring that tube. Wow. So the arm is able to detect molecules like

progesterone. So is it doing this by touch? Because usually we think about, you know, smelling or tasting molecules. Yeah. So what's interesting about the octopus system is it is chemosensation, but it's chemosensation in a contact-dependent manner. And the way that this works is the receptors that it uses, the proteins that actually detect these molecules in the arms, are really good at binding poorly soluble molecules. And so these are molecules that won't defy diffuse far in the water and are usually affixed to surfaces. And so the hectic cartilus senses progesterone, which itself is a relatively insoluble molecule. And what it uses is these same receptors that we've previously discovered are important for sensing microbial signals, but now

it's using them to instead sense steroids. So once a male and a female octopus do connect with each other, do they get all twined up with each other? I mean, that eight arms. Well, that would be 16 arms, I guess. That's a lot. Yeah, I think, I mean, there's a variety of ways that this happens across species. For the species that we've studied in most depth, it's a pretty striking behavior. Even when they're separated with the barrier, but if they aren't, what happens is once the hecticotolus makes contact internally with the oviduct, both of the animals freeze. and the female even changes the pigmentation to become pretty pale. And they both will sit like this for even up to hours and they don't move.

And so you'd think, yeah, there would be sort of a tangled mess of arms. But actually, they're very still while the transfer of those per metaphor happens. Wow, for hours. What about the female? What's her role in all of this? The female aspect is really interesting. and we haven't been able to study this in too much depth yet, although we would like to. But the female makes a choice for mating in two ways.

One is behaviorally. So when the male probes the female with the hecticotolus, even through the barrier, sometimes the female will decide that, you know, this is not the right male for her, and she will swim away from the male. And then sometimes, you know, specific mating pairs work. We don't know why that is. And then the other thing that the female does, that's really cool, is mating can happen many times in a female octopus's life.

And we can see this even by looking in the oviduct where sperm can be stored, actually, from different mating attempts. And we actually can see sperm both from the same species but also different species that try to mate with this specific female. And then once the female decides to fertilize the eggs, she'll maintain the eggs till her death. So this is a very final decision. And what's really interesting is somehow the female knows or makes this choice about which sperm to use for fertilization.

So how that selection process happens is really interesting toward asking these questions about how species barriers are maintained or perhaps how new species emerge through hybridization. Wow, that's amazing. So the female can choose which male sperm she is going to use to fertilize her egg. to choose the strongest or the best. That's right. By who knows what mechanism, but somehow. Dr. Bolano, thank you so much for your time. Thank you.

Dr. Nick Milono is a professor of molecular and cellular biology at Harvard University. Paleontologists are experts that scraping through the planet's earthly archives, looking for fossils of our human ancestors. Our own Quarks and Quarks Archive may not be as old as the Earth's, but we have a treasure for you today to celebrate our 50 years on the air. In 1979, American paleoanthropologist Dr. Donald Johansson spoke with then host David Suzuki about the discovery of Lucy, a 3 million-year-old skeleton that's one of the most significant fossil discoveries in history.

Our entire picture of the evolutionary history of humans since the time of our ape-like ancestors is based on a few fossil skeletons. The work of the Leakees at Olduvai Gorge in Africa has pushed the dawn of human beings back over a million years. Now comes word that a find in a different part of Africa, Ethiopia, identifies our ancestors from over three million years ago. A skeleton dubbed Lucy more nearly resembles a missing link. Donald Johansson, curator of physical anthropology

in Cleveland's Museum of Natural History, discovered this skeleton, and he's on the line now. Dr. Johansson, could you describe the creature you've found? Do you think that the creatures that you've been studying are in a direct line in our lineage or were they a side shoot? No. If you were to take your skeleton and build it back up, put all the muscles and skin and so on back onto it, what kind of a creature would we see? Could you describe him for us? I think we would be...

Was there any social structure, do you think? Have you found groups of skeletons together? We have found... Where did you find them, and how? Dr. Johansson, thank you very much. Our 3 million-year-old ancestors, a very exciting find indeed. Thank you very much for calling. Thank you.

Bye-bye. Bye. That was an interview with Dr. Donald Johansson and former Quirx host David Suzuki, which aired on January 20th, 1979. I'm Bob McDonald, and you're listening to Quirks and Quirks on CBC Radio 1 and streaming live on the CBC News app.

Just go to the local tab and press play wherever you are. Coming up later in the prox, seeing those puppy dandelion seed heads through a physicist's eyes. If you go to a field and you see all these seed heads that are only half blown off, you actually know which direction the wind came from, which is pretty fun. They're like nature's wind bane's. If you sold somebody a loaded gun who you knew was in a vulnerable state and they shot themselves, I think it is murder.

Just because you're using the internet doesn't mean you get away with murder. I'm Damon Fairless. Host of Hunting Warhead. This season, I take you inside the business of suicide, and the places desperate people go when they can't find what they need in the real world. Hunting the Suicide Salesman. Available now wherever you get your podcasts. Dandelions are everywhere these days, in country fields, city, yards,

and stubbornly and sidewalk cracks. And these resilient plants, some might call them weeds, just keep popping up over the summer with more blooms turning into puff balls of seeds that the wind carries away. Unless your aim is to have a perfectly manicured lawn and dandelions are mucking it up, it's hard to conjure up strong feelings about these hardy yellow flowers, but that wasn't the case for a certain physicist who specializes in fluid dynamics and his young daughter. When they were out for a walk one day in Ithaca, New York,

they came upon a field of dandelions, and what they did from there left them with a sense of wonderment, curiosity, and a new research topic for him to pursue. Quirks and Quarks producer, Sonia Biting, spoke with this physicist and his colleague about their dandelion research. Here they are. Our lab is called In vivo Fluid Dynamics Lab. And although we use a lot of math and physics, we like to be in real world. Can you get that dandelion over there? Yeah.

We're walking sensors, and we sometimes engage these experimental tools as we walk around and engage with the world. My name is Chris Rowe, and I'm a system professor at Cornell University in the Department of Biological and Environmental Engineering. And I am a principal investigator of Ineval Fluid Dynamics Lab, where we look at the complexity of real-life organisms, a submerged in fluid environment such as air and water. That one's even better. Oh, yeah, get that one. So around May in upstate New York, its fields are filled with dandelion seeds and dandelion flowers. And with my now four-year-old daughter, but then like one or two-year-old daughter,

we would go on a walk and we would just pick a dandelion and engage our wind tunnel and then blow on it just like anybody else would. Nolan, do you remember when we did little experiment with the dandelion seeds? Yeah. And we took a dandelion and we tried to blow off all the seeds while only one side would come off. Do you remember? Yeah. Can you show me over here? Whoa.

I think of our breathing jet as like, you know, a wind tunnel. And our fingers are like a force sensor so that we can feel the difference, tiny differences in forces. We're very sensitive if you pay attention to it. Show me. We would notice that only the one side of the seeds come up, however hard you glow it. Whoa, there's only four left. and when I see something that kind of contradicts what it should be intuitively, I guess the brain gets triggered and that kind of inspired us to get to the bottom of life. Why does the other side of the seed resist my wind better than the one in front?

Here, try this one, but blow it forward like that. Oh, see, half of it is gone. And then I engage my force sensor to actually feel that, oh, it's so much easier to actually peel off these seeds. When I provide a force in certain direction, so I do a little experiment there. And now I'm really curious, what is the basis of these asymmetry in the way they come off? And excitedly, I go to Jenna and tell her, Jenna, try this. Tell me I'm crazy or not crazy. And then this is how it gets started. Yeah, I think I was just, it was like a normal Tuesday or something. Chris was like,

here's a dandelion. Use your finger for sensors and tell me what you feel. And I'm like, good morning. Yeah, hello, I'm Jeddah Shields. I am a PhD candidate in applied physics at Cornell University, specializing in biophysics where we try to take physics to understand the biological world. around us. And through Chris, I've now been learning fluid dynamics and the very fun biology that comes with that. When are you guys going to flower? Yeah, so the first thing we really did was like, okay, well, we have our mouth as our wind tunnel and our fingers at our force sensor, but that's at the end of the day a qualitative measurement. So we're like, let's just do something where we can quantify it. So we basically redid the very simple experiment. Anyone

can do by pulling off the seeds, blowing on the seeds. And we did that with actual fans. So we knew the wind speed and then we'd see how the seeds came off. Then we did that with a very sensitive force measurement device. And I basically just connected seeds to this force sensor that I could get data from and would pull the seeds off in different directions to measure an actual force that it takes to take these seeds off. The force sensor that was necessary was one that was meant to be used in a very sensitive measurement. For studying muscle physiology, or measuring a contraction force of a single muscle cell, to measure popping off the dandelion seed off of the seed hat.

Oh, so I would take the very tip of the seed, and I would super glue it to the center of those white fluffy hairs on the dandelion. I wasn't the one attaching single thread silk to like hundreds of dandelion. seed heads. How's the experiment going? It was going well. I got everything set up and then I sneezed on the dana lion and all the seeds are gone. So it was fun to watch for me and I'm starting again. Slowly Jenna getting really good at it. It was a little maddening but you know we did it. Thanks. This is dandelion 17. What we noticed is that these seeds And they're all pointing different directions of the seed head, of course.

But they like to generally be pushed upward. That looks good. Cool. Or towards the top of the seed head. They don't want to go to the ground, it seems like, from these morphology that we found. Whoa. Isn't it really cool? You can actually see really clearly the asymmetry and the attachment point. Where we actually saw the asymmetry is where the seed connects to the parent plant.

And around that stem, there's a little bit of a raised surface that acts kind of like a support that almost thickens that little stem and supports it. But there's one slit of an opening that this support is not present. And that's exactly the direction that dandelion likes to break off much easier. Yeah, yeah. So that's all the plant tissue and then that's the attachment tissue. Oh, and this little dimple. that we see, that's the direction where it would come off easily. Yeah, yeah.

So that way would be really hard to come off. And this way is the way that's easier to come off or there's like a lack of tissue. Where there is a support, when it starts to bend, it's like bending a thick material and breaking off a thick material is a little bit harder than breaking up a very thin material. So when the thin material is just bending by itself without that support, it's more likely that a little crack will start.

to happen and then hit that breaking of that little stem that connects the seed to the parent plan will be that much easier. Sideways, zero degrees, zero degrees. And that asymmetry in the support around this stem is in a preferential direction where when the seeds are pulled towards or pushed by the wind towards the center, the top of the entire spirit, of the seed head, that's what gives the asymmetry in it coming off. Okay, good. So when you blow on a seed head, the seeds facing you are all going to bend upward because of the way they are pointing.

If they come off, they'll then go towards the sky. Whereas on the seeds on the other side of the seed head that are away from you, because of the force of the wind, they will start pointing downward. So that is actually the wrong direction for them to come off the seed head. So that is basically like our hypothesis is why when you blow on it, the ones facing you come off because they're bending the right way. But the ones on the other side bend the wrong way, so they're not going to come off. Or you're going to have to blow really, really hard. Oh, they're not coming off.

Until you flip the seed head around and then they'll then be bending the correct direction. Look at them go. If you go to a field and you see all these seed heads that are only half blown off, you actually know which direction the wind came from, which is pretty fun. They're like nature's wind veins. So that fluffy fan at the top, which is called the poppice, that's basically, like, without that, it'd be really hard for the wind to, like, do anything to these seeds. It's because of that stem and that fan that the wind is able to, like,

apply any force to these seeds and actually apply a torque to the seeds, and that's actually really what breaks them off. They don't like being pulled straight out. They need to be pushed to the side to break easiest. So without that poppice, it'd be really hard to get that torque on the seed. And then once they're up, the poppice is what the wind drag is acting upon to get them to fly. So it's really those white fluffy hairs that are responsible for the flight. And I think the stem is really just giving that extra leverage.

Like when you use a crowbar to open something, you need that leverage. So I think that's what the stem is doing so that the force. which from the wind, which is acting on the fluffy hairs, can actually do anything for the seed. We see two main advantages. One, these seeds will much rather come up in an updraft over a down draft. You could imagine that if you blow down on a dandelion seed head

and all the seeds fell right by the roots of the original plant, that would probably be detrimental to all of them because they're now competing for resources in a really small space. But instead if you have an updraft and these seeds to get into the air, they can then get farther away. away. And that can, one, get them away from their mom so that they can get to a new area. And two, if they all get into different updrafts and they fly different ways, they're away from each other. And they can get to new areas, colonize new spaces, and don't have to compete for as much

resources. So that's the updraft versus down draft. Additionally, when you blow on the seed head, with a sideways wind, the ones facing you are going to come off. So like the first set will come off in a western wind. And the second, Second side will come off in an eastern wind. That way they're going to different directions is once again higher chance of getting to new areas where they can actually survive and less competition than if they all came off in one go

and landed together. So we kind of see this asymmetry as a way to spread the seeds out over a larger area so there's less competition and a higher chance of getting somewhere they can grow. Additional advantage of upward draft can be imagined from some more fluid mechanics point of view because fluid needs.

the bottom, the surface, our land, it basically flows at speed of zero. And then gradually, when the wind is blowing, that speed that is wind velocity that is zero at the surface gradually increases as you go away from the surface. And this gradual change as you increase in altitude in wind velocity, though that area where there's a growth in wind velocity is, boundary layer. And by having and being more sensitive to updraft, you're not only gaining an altitude, as you gain in that altitude, you're also then experiencing a faster wind blow. And higher you go, more away from boundary layer you'll get, and therefore you're gaining

even more advantage of perhaps catching a faster wind. And that's perhaps one way of fluid mechanics, again, further explains how their dispersion might take advantage and this trait might be evolutionarily beneficial. Well, for years have been trying to model dispersal of seeds and plants. And this is especially important when it comes to invasive species, understanding how they're going to get from one area to the next, like how fast are they going to spread where? They're going to spread where the chances don't bathe this new area. So the endelines, some people know them, some are used to them, but they are invasive species.

in a lot of places, or at least unwanted species in a lot of places. So our work can be used to help improve those dispersal models to understand ecology better, understand population dynamics of these plants so that we can see how the community of these plants will change in different weather conditions and new environments, which things that would be hard to do experimentally, but we could do with models. But the models are only as good as the initial information we have. So this invisible world of fluid mechanics, when you decide to look at it a little bit closely, there's a science and there's physics. And I want people to interact with this world in a more intentional way like that.

And with my now four-year-old daughter, she knows a little bit too much and she blows off on the side and then shows me, see, and then explains to me what's happening and turns out. around and blows out the rest of the dandelion's seat. It's fun because it's always out there except during winter, and we're out there when dandelions out and we get to keep interacting with it in a very fun way. That was Jenna Shields, a PhD candidate in applied physics, and Dr. Chris Rowe, who is an assistant professor and the head of the In vivo Fluid Dynamics Lab at Cornell University in the Department of Biological and Environmental Engineering. engineering. Computer models can be extremely useful tools. These simulations are handy for studying

systems that are either too costly, complex, or too dangerous to investigate otherwise. They allow scientists to study climate change or galaxy formation and to simulate disease outbreaks or see how cells react to different drugs. They enable scientists to probe the unprobable, and that's the idea behind digital twin technology, virtual copies of our organs that can predict how they'll respond to treatment. Well, in a new study, scientists created digital replicas of patients' hearts so that surgeons could fix life-threatening irregular heartbeats called arrhythmias. It was the first clinical trial of its kind, and the hope is digital twin technology like this can help usher in a new era of personalized medicine with custom-made treatments.

Dr. Natalia Tranlova is a professor of biomedical engineering, medicine, applied math and statistics, as well as the Director of the Alliance for Cardiovascular Diagnostic and Treatment Innovation and of AI Research and Health and Medicine at the Data Science and AI Institute at the Johns Hopkins University in Baltimore, Maryland. Hello and welcome to Quarks and Quarks. I'm very happy to be here. Thanks for having me. First of all, how much did the digital twin heart allow you to improve on how we treat arrhythmias? Well, I would say very much so with great pride and happiness because ablation, which is

the burning of part of the tissue in the heart to terminate arrhythmias, does not have a very high success rate. In patients with complex arrhythmias, like those that we have studied, the success rate is about 60%. And so a lot of these patients will come back for second or third or fourth ablation and they need to be re-hospitalized and to have the treatment done again. So in our case, because we provide an optimal plan for treatment that is tested in the digital twin of the patient before the procedure, the goal of that is to not have the patient get to re-hospitalized. So if it was 60% in the traditional way, how much could you improve it with your digital twin heart?

Well, we had 100% success, right. 100%. That's how it was. There were 10 patients. In one year, none of them came back. Wow, that's astounding. Well, what is arrhythmia? What's it due to the heart?

So in the normal functioning of the heart, before the heart contracts, there is an electrical wave that propagates. through the heart and triggers the contraction. That's what the heartbeat is. That electrical wave then disappears, if you will, and there is a pause during which the heart fills with blood, and that's very important. Otherwise, the blood cannot be pushed to the systemic circulation. So the proper propagation of this wave is very important. Aritemia is when the electrical wave that propagates through the heart does not go through the way it is expected in the normal heart. What it does is it catches on structural changes in the diseased heart. For instance, if a patient has an infarct, the infarct is a scar tissue that grows in the heart. And that scar tissue

actually can catch the electrical wave and the electrical wave starts to resuscary. circulate kind of in one place, around the place where it caught itself. You can think of it like a hurricane. Instead of contracting like contract relax, contract relax, it basically begins to quiver. So if you see a heart that has several of these little hurricanes around, it looks like a bag of worms rather than actually a nice pump that's contracting and pushing the blood out. Now, you mentioned ablation. How does that treat arrhythmia? Ablation finds that piece of tissue, scar and other semi-viable cells around it, that are attracting that wave.

And if you eliminate those, like burn them and make them a full scar, the expectation is the wave doesn't attach to these areas. the wave likes not just pieces of scar, it likes the kind of the sickly cells around the scar. Every scar around it has cells that are not normal. You know, in the process of dying of that tissue, some of the cells around it are semi-viable. And that's where the wave most frequently attach. And so, you know, if you burn it in a proper location, it will make the wave just propagating. around this new lesion that's created and not attached to it. Oh, I see.

Well, take me through this new process. How did you create a digital twin heart for each patient? We start with imaging. We specifically use what's called a contrast enhanced MRI. Contrast enhanced MRI gives you all these structural changes in the heart. So the MRI, from the MRI, we segment out the cardiac in the heart. So we create an image of the heart and also within the walls of the heart, we see the areas where we have this structural change, scar fibrosis, and we outline those.

And now we populate it with cells that are able to generate electrical properties. So what we start to do is we poke it with a little bit of electrical signals here and there. So this is something that you can do in the real heart, but I can in the virtual heart. So we basically induce the arrhythmia and then we look where it is. And then we determine, is that a good location for ablation? If we take the location that we found and put it back in the digital twin, we burn it in the digital twin as if doing the clinical ablation, and then we check again. This cannot be done in the clinic.

Wow. I guess it's a lot safer to, as you say, poke the heart in a digital realm than it is to poke a real heart and see what works and what doesn't work. So is the end result here that you end up with a map of where the doctors need to do the ablation, a very precise map? Yeah, you end up with basically like the shell of the heart on which the proposed ablation targets are marked. and the procedure is done in a procedure room, and in this procedure room, there is a system that drives a catheter. The catheter is in the heart.

That's the ablation catheter. And this catheter first goes around the cardiac chamber inside and marks the shape of the heart. Okay? And then our prediction is also the shape of the heart on a shell with locations where to ablate. That gets imported in that system and co-registered with the image that the catheter has acquired. And now the catheter can be directly driven to the targets. They see it on the screen.

Now, you mentioned earlier that these 10 patients are now 100% arrhythmia-free, So what was it like for you when you realized how well this treatment actually works? I mean, we expected that they will work quite well because we did the clinical validation a year before and we saw how much correspondence there was between all the abnormalities that we see on the digital twins that we can see manifest in the digital twins with the abnormalities, the actual patient. And also we could see that the arrhythmia's,

looked very much the same in the digital twin and in the patient. We already knew that. So we expected to do pretty well. I didn't expect nobody to come back for ablation. I thought maybe somebody will, but none of the 10 patients came back. So this is great. That exceeded my expectation. Well, considering how well your digital twin strategy worked on the heart, could it also be applied to other organs in the body? If you're talking about you, liver. The physics and the physiology of the organ is very important. The physics gear is electrical current flow and mechanics, the contraction. None of that is in the liver. So it is very specific. I think one needs to know very well the physiology and the biological underpinning of that organ

to be able to create a digital twin. And it's a long process. Well, how ready is your digital twin technology to be used in healthcare? It can be used. The issue is like what is the vehicle for doing that? I always feel I am the innovator. We are the people who test it and develop, you know, tests. It probably needs to be either a startup or already existing device company could pick this up, this technology.

it's a matter of where do I want to go as a researcher with a team, do I want to go towards that in this direction to bring it, to bring this scalable solution in healthcare, or do I want to come up with a different application that addresses a different disease or a different condition in the patient, like heart failure or something else? So this is what my choice is, basically. Yeah.

So you just want to stick to the research and let someone else make it commercial. If you ask me, that would be my choice. Dr. Treanova, thank you so much for your time. You're very welcome. It was my pleasure, actually. Really nice to be able to talk about our work. Dr. Natalia Treanova is the Murray-B. Sachs professor of biomedical engineering and professor of medicine and applied math and statistics at Johns Hopkins University in Maryland.

Weston, Weston, Weston. Just a reminder, we've got a question show coming up soon to kick off our summer programming. So if you've got any science questions you want answered, send them to quirks at cbc.ca. Now, you've already sent in some really fun questions, like this one from Drew Shedler in Rothsay, New Brunswick. My question is,

why do I see only deciduous hardwood trees losing their leaves in the fall while evergreen conifers do not? What are the evolutionary benefits and drawbacks of being a conifer versus a deciduous tree? Thanks so much. Great question, Drew. And here's the answer. My name is Sally Aiken.

I'm a professor in the Department of Forest and Conservation Sciences in the Faculty of Forestry and Environmental Stewardship at the University of British Columbia. There are different benefits and costs to being deciduous or ever. and there are different aspects of being conifers versus hardwoods or broadleaf trees. So evergreen trees have the advantage of not having to invest in all their new leaves every year. So they don't have to produce that entire leaf area for photosynthesis every spring and then lose it every fall. but by dropping their leaves, trees don't have to protect those tissues that are vulnerable to cold in the winter.

Leaves that are evergreen tend to have a very thick, waxy layer on them called cuticle, and mechanisms to prevent the kinds of winter drought or freezing injuries that can occur. So another advantage of being evergreen is that whenever the temperatures are favored, enough for photosynthesis to occur, they can be conducting photosynthesis, not at a high rate, but they will be able to conduct some photosynthesis. Dr. Sally Aiken is a professor in the Department of Forest and Conservation Sciences in the Faculty of Forestry and Environmental Stewardship at the University of British Columbia. And that's it for Quarks and Quarks this week.

If you'd like to get in touch with us, our email once again is Quarks at cbc.ca. webpage is cbc.ca.ca slash quirks, where you can check out our past episodes and find more information on the research we covered in the show. You can also follow our podcast, get us on SiriusXM, or download the CBC Listen app. It's free from the App Store or Google Play. Quarks and Quarks is produced by Sonia Biting, Rosie Fernandez, Amanda Buchowitz, and Sarah Hamilton. Our senior producer is Hannah Hoag. The special thanks to CBC Radio Arbor. Archives, Patrick Mooney, Ross Talley, and Zoe Baraklop. I'm Bob McDonald. Thanks for listening. For more CBC podcasts, go to cbc.ca.ca slash podcasts.