- [Announcer 1] Quality public television is made possible through the financial contributions of viewers like you, who invite you to join them in supporting PBS NC.

[piano intro] - Hi there, I'm Frank Graff.

How a high tech toilet can help save the planet.

How a bionic ankle can help a person walk.

And visiting St. Paul's Cathedral in London 400 years ago, We're talking tech on "Sci NC".

- [Announcer 2] Funding for "Sci NC" is provided by the North Carolina Department of Natural and Cultural Resources.

[light music] ♪ - Hi again, and welcome to "Sci NC".

Let's talk about bathrooms.

I know, the bathroom's convenient, the toilet works, wash your hands when you're finished, done.

Trouble is that is not the case in a large part of the world.

And that is a public health crisis.

Producer Rossie Izlar explains how North Carolina researchers hope to change that.

- There's a lot that divides us humans.

But one thing we all learn from a young age is that everybody poops.

And for all our advances in technology, humans haven't really figured out how to handle our excreta efficiently.

For one, half the world's population doesn't have access to a bathroom that properly stores and cleans sewage.

So that's a problem.

And two, although you might be fond of your porcelain throne, it's wasteful by its nature.

Flushable toilets use a gallon and a half of treated clean drinking water every time you flush.

That's why toilet engineers all over the world are trying to solve this most basic problem of what to do with our pee and poo.

- I usually say I clean up [bleep] water for a living, which I know you can't use that.

[laughs] So one of the big problems that we're trying to solve, and one that I'm personally very interested in, is we use drinking water to flush our toilets.

And as the climate continues to change and as water becomes more scarce and we have more droughts and more fires, we're gonna be using more and more drinking water and having less and less of it.

So we really need to conserve that precious resource.

- The gold standard toilet is flushable and connected to some sort of water treatment.

But it's expensive and takes an enormous amount of water, land, and energy to lay pipes and build treatment plants.

And even then, modern sewage systems are far from perfect.

For example, every year the US spends a billion dollars to remove fatbergs, which are essentially massive clogs made of wet wipes and cooking fats.

During the pandemic, these clogs went up by 50%.

Yep, everybody was using a lot more wipes and flushing them down the toilet.

But while our sewage system might not be the best, things could be crappier.

- In a lot of places, the toilet pipe just goes nowhere, out into the street or out into a creek or river.

- Toilets are absolutely a justice issue and a human rights issue.

So when you get contamination, particularly of drinking water with untreated waste water, it spreads disease, most notably diarrhea, which kills about half a million children a year worldwide.

So digging a sewer under a city that already exists is tremendously expensive.

And when you look at a city like Mumbai or Kinshasa, that are huge, millions and millions of people live there, the political will, the money to go and dig a new sewer under those cities, it's just not there.

It's very unlikely to happen.

- But that's where the toilet engineering comes in.

Brian, Lena, and their team are working on a toilet they hope will use way less water and help communities that need access to affordable bathrooms that work.

It's called the Reclaimer, and they're building it in this warehouse, in the appropriately named bay number two.

Sorry, I had to.

So this is a toilet?

- Well, this isn't exactly a toilet.

This is what we would call a back end unit.

So if you think of the toilet as your front end, everything that happens after the toilet in terms of treatment is the back end.

Ideally we envision this or something like it being an appliance you would have in your house that your toilet would be pumped to.

What that appliance does is it receives the wastewater from the toilets and it treats it on site.

It's not potable.

You don't want to drink it.

But it's good enough for reuse.

We like to use it for flushing the toilets themselves.

So you have just a continual reuse of water locally.

- [Rossie] But how does it work?

First things first, separate the poop from the pee.

The Reclaimer filters out the poop, pushing it to a separate container so that bacteria can digest it over time.

- We then take the liquid fraction that's left.

That goes to the inlet of the Reclaimer.

At the very bottom here, you have what we call our feed tank.

So that's where the dirty water comes in.

And you can see it's pretty dirty.

You can even see it through the tank.

- Disgusting.

- Yeah, absolutely.

So the very first stage is what we call ultra filtration.

And that's exactly what it sounds like.

We force the liquid through those straws.

And the straw itself is what filters the liquid.

- [Rossie] The liquid travels through three more filtration chambers, one that uses granular activated carbon like you'd find in a Brita filter, one that removes ammonia, and one that zaps the water with chlorine to kill any foul smelling bacteria.

And after that, the water can be used to flush the toilet again.

Brian's team is testing the Reclaimer in India at a cotton mill.

- A lot of the brunt of sourcing clean water for the family falls on women and girls.

And so women and girls can't have other jobs, or they have to travel great distances and miss school just to provide clean water for their family.

And so if there's a way that we can, again, conserve drinking water so that those trips need to be made less frequently, women and girls can live fuller, richer lives doing other things besides going to the well.

- [Rossie] The team is also hoping the Reclaimer can be used in the US in places like Utah, California, or Nevada, all states experiencing record breaking droughts and huge population growth.

- Right now, we use a lot of water just to flush all of our waste to the treatment plant.

But if you're treating the water on site, you can use much less water and you can reuse it right where you need it.

I spend so much of my time in the lab and we often don't get to see our inventions and ideas out in the world.

And so that's been something that keeps me really motivated here.

[laughs] But if you had sold me two years ago, I would be working with human waste and shoveling it into experimental toilets I would not have believed you.

[laughs] - Still with health and technology, patients suffering serious injuries, such as losing an arm or a leg, are often prescribed a prosthetic limb.

Producer Evan Howell shows us the next generation of prosthetics.

[dramatic horn music] - [Evan] The first documented artificial limb dates back to ancient Rome and General Marcus Sergius, who had a prosthetic hand made of iron so he could hold his shield in battle.

Yes, he's known as the first Ironman.

[cheerful flute music] Engineering evolved up to the Civil War when amputations were still the only viable option for many soldiers rooted in the field.

In 1866, North Carolina became the first of the Confederate states to offer artificial limbs to its veterans.

The Jewett Leg Company was established in Raleigh, where it offered limbs to over 1500 amputees.

It adds some moving parts, but not much else.

[futuristic music] - To be able to actually use them again, it's odd.

- [Evan] Greg Phillips lost his leg below the knee in 2013 after a motorcycle accident.

- [Aaron] So as soon as you do push off.

- [Evan] Researchers at NC State and UNC Chapel Hill are working on a revolutionary device that may change how artificial limbs are engineered.

- So things that are difficult with a normal prosthesis, like picking something up off the ground or carrying heavy loads from the ground, even going from sitting to standing is difficult sometimes because with a normal prosthesis you don't have that flexibility, you don't have that control.

Try your toes up.

- [Greg] For me, the most difficult part was learning how to fire off those muscles again.

After seven years of not using the muscles at all, they succumb to atrophy and just become flabby.

- [Evan] The team is designing a prosthesis that actually follows a user's commands by responding to the signals sent from their brain.

If it works, that would be a major breakthrough.

Right now, most prostheses are attached to the limb and stay static, only moving if the limb moves, The ankle joint is the key part of what makes this new limb unique.

The team has engineered a system to help mimic normal muscle behavior so they can test what works.

No one knows when it will be available to the public.

The biggest challenge now is making it a lot smaller.

So how does it work?

Sensors are placed in the front and the back of the leg.

The sensors detect signals sent from the brain to the muscle.

The muscles now control the direction of the ankle.

Air is then pushed into tubes around the ankle and those tubes work just like muscles.

- [Aaron] So this is, in a normal prosthesis he wouldn't have the flexibility that this ankle does.

Instead what you would see is the heel to actually come up off the ground.

So by having the flexibility and the control, he's using his own effort and he has the flexibility to squat down as far as he wants.

- [Evan] Retraining the brain to establish a symbiotic relationship between a human and a machine can be tough, and that's why neurological scientists are part of the team.

- Our research is very unique that we need multidisciplinary collaborations.

So as an engineer, we know how to make the device and make the control work, we know how to collect the data, analysis the data, but that's not enough.

As a part of the body limb we wanted to use this device naturally.

Sense those devices naturally.

That required this connections, seamless interface between the human and the device.

- [Evan] And for, that Wong and Fleming turned to Frank Hodges, a clinician who's been fabricating prosthetics for decades.

- There has to be a little bit of interpretation as to what they're feeling and what needs to be done.

And that's when it gets a little tricky.

- [Evan] He needed to figure out how to engineer a prosthetic socket that would be comfortable, but also sensitive enough for signals to travel back and forth between the sensor and the ankle motor.

- Sometimes their feedback isn't direct to the problem.

Sometimes it's a referring pain or just a feeling that they get of unsteadiness.

[chill music] - So there's a huge question that needs to be answered of what does it take for someone to regain function using those muscles to actually effectively control a prosthesis?

- [Evan] And Greg Phillips wants to help answer that huge question.

He says that while he won't be able to take one of these things home, he says if someone down the road can, he's proud to be part of that process of discovery.

- [Greg] It's still incredible that those feelings haven't been there for seven years.

- This is St. Paul's Cathedral in London as it looked 400 years ago.

Now it's not a video game.

It's a research tool developed at NC State.

That's because religion in 1620 was not just about faith.

It was the government.

[thunder rumbling] - [Frank] This isn't a new video game.

It's a research project.

[thunder rumbling] That's St. Paul's Cathedral in London.

- [John] Visually it was the dominant image on the horizon.

[bells pealing] - [Frank] It is Easter Sunday, March 28, 1624.

- So it became the center of cultural life as well as religious life and of social life for the entire city.

- [Frank] Modeling the past provides a new way to access the past.

- But I don't think you can say that St. Paul's Cathedral is just a church.

It was the center of life, of public life, of religious life, in London.

- [Frank] And a team of scholars at North Carolina State University believes St. Paul's Cathedral is the best portal to provide a glimpse of daily life and understand London in the 1620s.

- So I think we were really curious to understand what that looked like in the 17th century, what it sounded like.

Imagine, even, what it smelled like when you see some of the renderings.

You feel like you're there.

We wanna understand the air quality.

We wanna understand the light quality.

How the building changed because of those things, how it weathered and got a patina over time.

And so the model allows us to do that.

[bells pealing] - [Frank] They recreated the sites and sounds of the cathedral and the surrounding neighborhood into a 3D model that you can interact with on a computer.

Call it architectural archeology.

- [David] So archeological records tell us where the old cathedral was.

So we had a great degree of certainty about its footprint.

- [Frank] Researchers draw on written accounts, drawings, and paintings.

[bells pealing] - There is indeed an enormous amount of visual material and archeological evidence that survives from this period.

So we know generally what the place looked like, and we know how big everything was and where things were located.

So we have the elements that we need to build a model of it.

Here's a chance to experience what reformed worship was like in London in this cathedral.

- There are many different iterations of all of these columns.

What you see here was not the first thing that was built.

It's build, fact check, rebuild, fact check, build again.

And then when it gets to the coloring portion for the renderings that you see on the website, it's paint, render, fact check, repaint, render, fact check.

- [Frank] And it turns out weather records were carefully kept during the time.

That's important, because cathedrals were designed to take advantage of sunlight and shadows.

- Behind us is the interior model.

And the most important thing with that is, I don't know if you've been in cathedrals in Europe, but the grand scale and the filtering of light coming through the windows.

It's very important to get that atmosphere right to making it feel correct.

- So you don't just say, "All right, sun's up here.

Boom, blast of light coming down."

You're factoring all that stuff in.

- No, it it's about, is the sun going to be right here or is it gonna be right here?

Because between the two of them you'll get different reflections and seeing an image where everything is mostly right.

It's about the suspense of disbelief.

So orienting this proper north south and getting the actual sun angles and being true to life, sun heights, and doing atmospheric modeling, Introducing smoke and smog to those calculations.

The computer program is smart enough to figure all that out.

I just have to tweak and tweak and tweak.

[choral music begins] - [Frank] Researchers even hired an international collection of singers and actors to recreate services from Easter Sunday, March 28, 1624, as well as an ordinary weekday service in 1625.

- It's amazing that we're able to go back in time and figure out what things looked like back then, and be able to see how people lived and how people built buildings and how people used them and how the choirs sounded in this building back then.

[choral music continues] - [Frank] So why do all of this?

Well, it's important to remember the church's role in 17th century England.

The king was the head of the country and the head of the church of England.

People were legally obligated to attend church.

[bells pealing] - The church of England was a state church.

The monarch was officially the supreme governor of the church of England.

The sermons in the cathedral and in Paul's Church were often sermons that addressed political issues.

- [Frank] In short, the church is a window to the art, culture, literature, and broader history of the times.

- [John] We're able to pull all that data together into a powerful visual realization of what it looked like.

[bells pealing] We can not simply know as an abstract idea, but, in fact, experience what that was like and how people were formed and how this shaped and informed their lives.

- Trail cameras have provided new insights into animal behavior.

Now the cameras have motion sensors, so they only capture images when animals walk by.

That allows them to operate for a long time.

And that is giving us new insights into the life and death competition between the coyote and the fox in an urban environment.

[melancholy music] The story of the coyote is also the story of how nature adapts.

- Coyotes originally were only in the Western United States.

They were in sort of open habitats, deserts, prairies, and things like that.

And then in the 1900s, we killed all the wolves in the eastern forests and coyotes started moving in and are now pretty much everywhere in North Carolina.

- [Frank] As cities and towns grow, that means there's a lot less forest and open area for animals to live in.

So species must adapt and learn to survive in those fragmented landscapes.

Coyotes are leaving the woods.

- Coyotes are one of the most adaptable species on the planet.

What we see in North Carolina is when they first got here, they filled up all the natural habitats and out in the more rural areas.

And now that they filled that up, we see them starting to move more and more into urban areas.

- [Frank] The coyote is not only adaptive, it's also competitive, and that can be a loss for other species.

- And some of the species that they compete with are similar to them like foxes and bobcats.

And so they're enemies.

The coyote and the fox are basically arch nemeses.

- [Frank] As more coyotes move into urban areas, researchers at the North Carolina Museum of Natural Sciences wanna understand their impact on gray foxes.

Gray foxes were in the woods first.

[light music] - We set up this big camera trap array to monitor wildlife from an urban to wild gradient.

'Cause we wanted to see not only where the species live along that gradient, but also how these two species, the coyote and the gray fox, were interacting.

So was the gray fox avoiding the big, mean coyote?

We found that in urban areas, they were basically both coexisting although coyotes were much more rare.

In rural areas, if there was enough tree cover, they coexisted.

Where there was no tree cover or lower tree cover there were only coyotes.

So we think this tree cover might be a really key factor that helps them coexist.

And part of that might be because of the fox's ability to climb trees.

We call sometimes the gray fox the cat like canid because they have semi retractable claws.

And they're basically one of the only canids that's able to climb trees and we think this might help them avoid the coyote.

- [Frank] Researchers say the key to preserving both the native gray fox and the non-native coyote lies in the habitat that humans leave for both of them.

- So if we wanna help these two species coexist, which they can, we really need to keep the tree cover.

So it means preserving forests that we already have and maybe reinforcing areas that have lost some of that tree cover.

- [Frank] But if the forest habitat continues to be lost, pushing coyotes more and more into urban areas, owners of small pets will have something else to worry about.

- Coyotes are a decent size predator, and it's not only the foxes that they bully or can potentially prey on.

It's also other species.

And in some ways it's a good thing, 'cause it sort of maintains the balance of nature.

But on the other hand, if you let your cat outdoors, the coyotes are a real risk.

And we are seeing in our neighborhood as the coyotes have increased in the last couple years, more and more lost cat signs.

- [Frank] One cause of that increased risk is offering food to wild animals.

- Feeding wildlife, the bigger mammals, is usually something you wanna avoid doing because you might be attracting something like a coyote which could start causing problems for you or for your neighborhood.

- Okay, I admit in a show, focusing on technology, brushing your teeth is pretty low tech.

But if you're a zookeeper at the North Carolina Zoo and you are taking a rhino to the dentist, NC Culture Kids went along.

- Hey everyone, I'm Emily.

I'm at the North Carolina Zoo in Asheboro, and I'm here to find out, do rhinos go to the dentist?

[quirky music] ♪ So to answer that question I have with me zookeeper Stacey.

Stacey, thank you so much for being here with me.

My big question is do rhinos go to the dentist?

- Of course we can't take a rhino to the dentist office.

So we have a rhino dentist that comes to our rhinos.

And although our rhinos are very attractable and we have them trained to do all kinds of neat behaviors, which includes opening their mouth, as far as a thorough exam, we do have to use some sedation.

So just using some medicine to make her go to sleep for a little while so that the dentist can really open her mouth and get a good look in there.

For Abby, she is a very sweet and calm rhino.

So we're actually able to do the injection voluntarily.

So Abby actually allows the vet to use a syringe and needle to give her an injection of the medicine that will make her sleepy and go to sleep for a little while so she, of course, doesn't feel anything.

So we wait for the medicine to take effect and then she lays down and then we all go in and start positioning her and opening her mouth up for the dentist.

Today the procedure was to float her teeth.

The tool is called a float and all it is is a file.

So he opens mouth and just smooths out the teeth and cleans the teeth just like you when you're at the dentist, you get your teeth cleaned.

They do that with horses.

You'll really hear it's common with horses and rhinos and horses are actually very similar.

Then everybody clears out 'cause she is 5600 pounds.

And so we don't wanna be in there as she's trying to get to her feet.

But they give her the medicine that reverses the sedation and now she wakes up and she stands up and is okay.

[laughs] And that's what happened today.

It takes some time to wake back up and she'll go back with her friends.

- So it sounds pretty similar to a human dentist appointment, but maybe instead of Abby going somewhere, it's like a house call, the dentist makes their way to her.

- Yes, and the dentist that came to work on Abby today, he is known as a rhino dentist.

So he goes all over the country helping rhinos have healthy smiles.

[laughs] - I love that so much.

And I'm so happy to hear that Abby is gonna do so much better after this procedure and live out this wonderful, amazing life here at the zoo.

- [Stacey] Yes, she should recover well and continue to be sweet Abby and have healthy teeth to eat.

'Cause one of their favorite things to do is eat.

[laughs] They eat a lot.

- Well 5,000 pounds, yeah, I'm sure one of their favorite things to do is eat, for sure.

Awesome, well, Stacey, thank you so much for teaching me all about rhino dentistry and rhino teeth.

I really appreciate.

- Yeah, sure.

[cheerful music] - And that's it for "Sci NC" for this week.

If you want more "Sci NC", be sure to check us out online.

I'm Frank Graff.

Thanks for watching.

[bright music] ♪ - [Announcer 2] Funding for "Sci NC" is provided by the North Carolina Department of Natural and Cultural Resources.

[bright music] ♪