Learn about how quitting smoking may reawaken healthy cells; how researchers figured out how to tell the age of crime scene fingerprints to help investigators; and why you sometimes yawn while exercising or singing.
Learn about how quitting smoking may reawaken healthy cells; how researchers figured out how to tell the age of crime scene fingerprints to help investigators; and why you sometimes yawn while exercising or singing.
Quitting smoking doesn’t just slow lung damage, but can also reawaken undamaged cells by Grant Currin
It's been impossible to tell the age of crime scene fingerprints — until now by Grant Currin
Why we yawn during exercise by Ashley Hamer (Listener question from Kate in Pennsylvania)
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/when-smokers-quit-dormant-lung-cells-wake-up
ASHLEY HAMER: Season's greetings, we're wrapping up the year with a look back at your favorite episodes of 2020.
SPEAKER: Enjoy this Curiosity Daily classic. And stay subscribed for brand new episodes starting January 1.
CODY GOUGH: See you in 2021.
Hi, you're about to get smarter in just a few minutes with Curiosity Daily from curiosity.com. I'm Cody Gough.
ASHLEY HAMER: And I'm Ashley Hamer. Today, you'll learn about how quitting smoking may reawaken healthy lung cells and how researchers figured out how to tell the age of crime scene fingerprints to help investigators. We'll also answer a listener question about how normal it is to yawn when you're exercising or singing.
CODY GOUGH: [YAWNS] Satisfy some curiosity. If you or someone has been thinking about quitting smoking, then I've got some good news. An international team of researchers has discovered something surprising about the lungs of people who have stopped smoking. It turns out, they can partially regenerate themselves, thanks to certain lung cells that are somehow protected from the cancer-causing chemicals in tobacco smoke.
This means that quitting smoking doesn't just slow the accumulation of further damage, it can also reawaken cells that have not been damaged. So here's the science behind this pretty compelling reason to quit cigarettes for good. There are more than 60 chemicals in tobacco smoke that cause the DNA in lung cells to mutate.
We're talking somewhere between 1,000 and 10,000 mutations per cell. Some of those mutations cause cells to grow uncontrollably, and that's what causes lung cancer. Experts used to think these mutations lasted forever, but there's new evidence that your lungs protect a few healthy cells that can replace cells with mutated DNA, even if you smoked a pack a day for decades.
In the new study, researchers compared DNA from the lung cells of 16 people, which included current smokers, former smokers, and people who had never smoked. DNA from the former smokers contained a surprise. Their lungs had recovered way more than the scientists had expected.
Up to 50% of their lung cells looked like they had come from people who had never had a cigarette. The researchers weren't able to watch the process for themselves to see exactly how the DNA recovered. But it looks like a few healthy cells somehow avoided damage from tobacco smoke.
One of the researchers said it was like they were in a nuclear bunker. When someone quit smoking, those cells apparently come out of hiding and start to grow, divide, and replace mutated cells. One of the researchers involved in the study told the BBC, quote, "patients who had quit even after 40 years of smoking had regeneration of cells that were totally unscathed by the exposure to tobacco," end quote.
This is some of the first work on this phenomenon. But these surprising results will probably inspire a wave of studies into how lungs protect themselves from DNA mutation and cancer. And maybe they'll inspire a few smokers who needed one more reason to quit.
ASHLEY HAMER: Researchers have found a new far more accurate way to determine the age of a fingerprint. And this is kind of important because up until now, it's been impossible to tell the age of fingerprints at a crime scene. These new findings could help investigators put the right bad guys behind bars. So put on a funny hat and grab your magnifying glass. It's time to go sleuthing.
When we think of what makes fingerprints unique, we usually think about their physical pattern-- those arches, loops, and whirls that are distinct from person to person. But in the last decade, researchers have turned their attention to a fingerprints chemistry. Studies have already shown that fingerprints contain chemical signatures that offer clues about a person's sex, ethnicity, and certain aspects of their lifestyle. And now, researchers are figuring out how those chemicals change over time.
To be fair, we weren't completely in the dark when it comes to age. Forensic scientists have known for a while how to use chemistry to tell whether a fingerprint was more than eight days old. But while that's helpful information, it's not exactly super precise. This new finding hinges on how the environment interacts with the oils that a fingerprint leaves behind. Specifically, the researchers studied evidence of chemical reactions between ozone and the air and lipids called unsaturated triacylglycerols.
The researchers used a method of chemical analysis called mass spectrometry imaging to track how levels of the triacylglycerols has changed over time. What they found was surprising. It wasn't that hard to figure out how quickly triacylglycerols glycerol reacted with ozone and degraded into other compounds. But it did turn out that the rate was different from person to person.
This was a small exploratory study so the researchers only used fingerprints from three volunteers. Two of those volunteers fingerprints degraded at about the same rate. But the third volunteer's fingerprints degraded more slowly. The researchers aren't exactly sure why, but it looks like the third person had higher levels of lipids in their fingerprints. This suggests that in addition to having a unique fingerprint pattern, people might also have distinctive triacylglycerols signatures. That means investigators using field tests based on this research will probably have to know who left a fingerprint if they want to figure out how old it is.
But soon, suspects won't be able to lie and say they visited a victim weeks before the murder. Thanks to this research investigators will already know when they were there. They'll just have to analyze their fingerprints.
We got a listener question from Kate in Pennsylvania, who writes, I always yawn while trying to sing and while exercising. I was wondering if this is common. And if so, why does it happen? Great question, Kate. The short answer is, yes, your issue is fairly common. I personally yawn all the time when I'm at the gym regardless of the hour. And if you ask my singer friends, yawning while singing is also a known issue. But why does it happen? Let's dig into the science.
The most common belief about why we yawn is that it boosts our supply of oxygen. That makes intuitive sense since when you yawn, you take in a big gulp of air and even seems to explain why yawning is contagious. The idea is if there's a drop in oxygen, yawning signals that to the people around you so they can yawn, too. Except that's been entirely debunked.
For a study back in 1987, scientists had people breathe air with different mixtures of oxygen and carbon dioxide. None of the air mixtures had any effect on participants yawning. The researchers concluded that breathing and yawning must be controlled by separate mechanisms. The strongest theory for why we yawn, if you ask scientists, this is going to sound weird, but it's to cool your brain.
So here's the logic, yawning consists of two basic components. First, you open your mouth, which stretches the jaw muscles and boosts blood flow to the area, which is part of your head. You also take a deep breath. And when all that cool air hits your tissues, it cools the blood flowing through them. And that cool blood travels to your brain and turns down the temperature.
I know what you're thinking, I yawn when I'm tired, or when I wake up in the morning, or when I'm bored, not when my brain is hot. Well, all of those things are linked to an increase in brain temperature. And physical stressors like exercise boost your core temperature, which also heats your brain. Yawning helps bring your brain temperature back to baseline, but only if the ambient temperature is right. You actually yawn less when it's very hot and very cold.
As far as singing, the science is less clear on that. But it could be a few things. You might just be working really hard and raising your core temperature. There's also the fact that a good throat position for singing is super similar to the beginning of a yawn. In fact, that's how many teachers will instruct their students to sing. That starting yawn position might just be going over the edge into a full-blown yawn. Thanks for your question, Kate.
If you have a question. Send it in to podcast@curiosity.com or leave a voicemail at 312-596-5208.
CODY GOUGH: Before we recap what we learned today, here's a sneak peek at what you'll hear next week on Curiosity Daily.
ASHLEY HAMER: Next week, you'll learn about how to tap into your friends to help you exercise better self-control, why a rising robot workforce could make humans less prejudiced, how to beat procrastination not by managing your time but by managing your emotions, what researchers learned in the largest ever study of cancer genomes and more.
CODY GOUGH: You'll also hear the first part of our series of interviews with author David Owen, who will tell us about how your sense of hearing works and why it is very important to protect. So now, let's recap what we learned today.
ASHLEY HAMER: Well, we learned the very good news that if you quit smoking your lungs can actually recover because scientists have figured out that they hold on to some healthy cells and protect them, and then those healthy cells proliferate once you've quit.
CODY GOUGH: Yes, one more reason to quit, which you should do if you smoke cigarettes. And we also learned that police are now maybe going to be able to date how old fingerprints are, which they weren't able to do before. People think that forensic science is a lot more advanced than it really is.
ASHLEY HAMER: Yeah, the more I learn about science the less I can watch those like CSI shows.
CODY GOUGH: Yeah. Please realize those are not documentaries.
ASHLEY HAMER: Definitely.
CODY GOUGH: We also learned why we yawn while we sing and while we exercise, fortunately not while we podcast.
ASHLEY HAMER: Sometimes. Actually, I'm very surprised that I didn't yawn at all during that segment, but I bet I made some listeners yawn because just talking about yawning is enough to make some people yawn.
CODY GOUGH: Did you see me do it?
ASHLEY HAMER: Did you do it? Yes.
CODY GOUGH: It happened. And we think it's because yawning cools our brain, that's the leading Theory but researchers don't actually know why we yawn.
ASHLEY HAMER: Right. It's so simple and yet so mysterious.
CODY GOUGH: It's like how it took us like a zillion years to figure out how our shoes come untied.
ASHLEY HAMER: Yeah. I love that stuff.
CODY GOUGH: Those little things.
Today's stories were written Ashley Hamer and Grant Curran and edited by Ashley Hamer, who's the managing editor for Curiosity Daily.
ASHLEY HAMER: Special thanks, by the way, to Sarah, Danielle, and [INAUDIBLE] for their singing help on that question. Today's episode was produced and edited by Cody Gough.
CODY GOUGH: Have a great weekend and join us again Monday to learn something new in just a few minutes.
ASHLEY HAMER: And until then, stay curious.
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