SciTech Now Episode 341

In this episode of SciTech Now, from the PBS Documentary film Military Medicine: Beyond the Battlefield, we meet a veteran who is given new hope with a robotic arm; Yael Kiro, at Geochemist at Columbia University is studying the mysteries of the Dead Sea; unlocking the scientific secrets of a rare wood collection; and the changing world of plants.


Coming up... A robotic arm gives one veteran new hope...

We've got to push technology.

Guys behind me in future wars can have something that will make their lives better.

...mysteries of the Dead Sea...

We learn a lot about climate.

We can learn about past earthquakes.

... a rare collection unlocking scientific secrets...

100 years ago when this collection was started, it was really just more about collecting them and having them and not exactly knowing what you're going to do with it.

... the changing world of plants...

It has to become, let's say, inefficient at collecting the light because if it were too efficient, it would literally burn up.

It's all ahead.

Funding for this program is made possible by... ...and contributions to this station.

Hello, I'm Hari Sreenivasan.

Welcome to 'SciTech Now,' our weekly program bringing you the latest breakthroughs in science, technology, and innovation.

Let's get started.

Thanks to advancements in military medicine, rehabilitation, and technology, thousands of military service members who were severely wounded in the wars in Iraq and Afghanistan are not only surviving their injuries but are returning home to the lives they wanted to live.

In this next piece from the PBS documentary film, 'Military Medicine: Beyond the Battlefield,' we meet retired Army Sergeant First Class Ramon Padilla.

He's turned his injury into a cutting-edge continuation of his service.


Ramon Padilla is a father and husband, a retired Army Sergeant First Class who served two tours in Iraq and Afghanistan, and he is the second person in the United States to have this prosthetic arm.

The arm's technology is the first to use implanted sensors to transmit signals to the robotic hand, and its thumb moves, unlike Padilla's older prosthetics.

Before, with this hand, I would have to move my thumb over, close it and grip.

And now with this one I don't have to move my thumb over.

I can just power it over and just close it.

It's been 9 years since Padilla lost his arm, and more than 16 years since he volunteered to join the Army.

I was born in Mexico, and I got to the States when I was 2 years old.

So I grew up in Southern California, about 13 miles east of Downtown L.A.

I had two daughters at an early age.

I had my high school diploma.

And something just clicked where it's like, 'Okay, I need to give back.

I need to do something.

My family has taken advantage of everything the States has given to us,' and I just felt that I had to give back.

In May of 2007, Padilla was a Staff Sergeant with the 173rd Airborne Brigade Combat Team.

He'd already done a tour in Iraq and served 7 years in the Army when he was sent to Afghanistan's Korengal Valley.

Well, it was July 8, 2007.

We just had gotten back from patrol.

Every time I came out of that hooch, I look up to the mountains.

And I looked up at some area that was known for the enemy to be there -- all the time.

All the time.

I mean, every time I pass through there, I look, I look, I look.

Well, that one time I didn't look, half second later, RPG blows up next to me, shrapnel severs my arm.

I got shot on the right side of the head.

You know, the only time I don't look, it's where they fire from.

Losing my arm was the least on my mind.

Getting shot in the right side of the head was the least on my mind.

What I cared about the most is the safety of the warriors that were there with me.

Under fire, his team got Padilla out of the valley.

Just 6 days later, Padilla was on a critical-care air transport flight from Germany to the Walter Reed Army Medical Center, where his recovery began with a question for his occupational therapist.

The first thing I asked them, 'Look, I want to learn how to play catch with my kid.'

Because I have a lot of fond memories of me and my dad playing catch and teaching me how to play baseball and stuff like that.

Those were a lot of special moments in my life where I do remember, and I wanted to give that to my kids.

Having one arm, I had no idea, 'How the heck am I supposed to do this?'

And he tells me, 'We will get you to catch with your kids.'

What Padilla and many young wounded warriors wanted was for medical technology to catch up with them.

Padilla now uses a modified lacrosse stick to play catch with his son and a metal grip for golf, but it started out slowly.

Well, my first hand was my dummy hand, what I call my dummy hand.

So it does not move.

It does not do anything.

It's just a passive hand you put on.

Well, what I wanted was a Luke Skywalker 'Star Wars' hand, of course.

And then later, I wanted the 'I, Robot' Will Smith hand.

And those are the two hands I really wanted because was like, 'Oh, my God, this is in the movies.

It has to be true, right?'

Offered a chance to participate in the trial of a robotic arm that would mean having surgery to implant sensors, Padilla was an eager volunteer.

They implanted electrodes inside my muscles.

So the same muscles you use to move to close your hand left to right, thumb, those are the same ones I use to power this prosthesis.

So electrodes are on the same muscles.

At the Alfred Mann Foundation in Los Angeles, scientists worked with military doctors to design the surgically implanted sensors.

The tiny devices detect signals from the existing muscles in the amputated limb, transmit the information wirelessly to the arm's controller, where the signal is translated into commands for the robotic hand and arm to move.

It's slow, of course.

It's not gonna be as fast as your hand.

But as soon as I do it, it happens.

So whatever your process is, from your brain to your muscles to your nerves and everything, however that works, it works.

Let's go this way.

This life-changing technology not only gives Padilla more independence and freedom, it also brings him a step closer to the future he wants for his family and for future generations of wounded troops.

The way I see it is, we've got to push technology.

I mean, to me, it's like giving back.

It's like serving again.

Because even though you may call me a guinea pig, or crash test dummy, whatever you want to call me, all right, I don't care.

It's fine.

I'll be that, so that way guys behind me in future wars can have something when they come back injured, something that's positive, something that will make their lives better.

To see the full documentary, 'Military Medicine: Beyond the Battlefield,' visit

The landlocked Dead Sea of the Middle East is Earth's lowest spot on land.

The current Dead Sea shoreline lies about 1,300 feet below sea level, but it's dropping at a rate of about 4 feet per year.

Yael Kiro is a geochemist at Columbia University, and is using layers of salt from the sea bed to study the significance of this change.

This segment is part of our ongoing series of reports, 'Peril & Promise: The Challenge of Climate Change.'

So thanks for joining us.

Thank you.

What do we learn from digging down into a sea bed, well, mostly a salt bed?

So, we can learn several things.

We learn a lot about climate.

We can learn about past earthquakes.

I'm specifically reconstructing a rainfall during the most dry periods, during the time of the drilling.

Okay, so this piece of salt that we have here.


It's a crystalline form.

How old is this?

This is around 120,000 years old.

120,000 years old.

So what do you learn from seeing that piece of salt about the climate that was happening at the time at the Dead Sea?

So, we know what is the amount of salt that we have in the drilling.

And inside the salt, we have these small bubbles of liquid that trapped the water of the lake during that time.

And we can analyze the composition, what is the dissolved salts inside these small bubbles.

So we use this, and how much salt do we have, and reconstruct how much fresh water flowed into the lake in the past, and then we know what was the past climate and what was the rainfall.

So, what surprised you?

Did you think that there were droughts as significant as the ones that history sort of revealed?

We knew that there was a significant decrease in precipitation and it was a drier period, but now we were able to quantify.

And I didn't think that it would be as much low than what it is now and what is expected in the future.

If we're doing things now to kind of accelerate the warming of the planet, compare that to 120,000 years ago or whenever it was, where there were warm periods as well, but just not humans accelerating it.

Yeah, so, today, we see the lake levels dropping and salt is forming in the lake due to anthropogenic influence.

But what we show... We are talking about the water that is available to people in the system.

So today, all of the water that flows into the Dead Sea is used by the countries around the Dead Sea -- by Israel, by Lebanon, by Syria, by Palestine.

And we are showing that the water stress may be even larger in the future because of warming.

Models, for example, are expecting that there will be a decrease by 20% in water availability, but what we show that under natural conditions, it can go down by 80% due to warming.

So we have here an independent research that may show that things may be even worse than what we think it would be in the future.

So even with no humans around, it had reached bottom with 80% below levels.


And here we are now, with humans fighting over that limited resource of water, and they're predicting it can go down 20 percent.

But you're saying it could get much, much worse.


How does this data compare to other climate-change models that we have?

I mean, when you go get a core sample, this isn't the Arctic, the Antarctic.

But you are getting a moment in time.

Yes, so we have different climate records.

We have marine records or ice core records, and each one of these records are showing different records.

For example, temperature, or concentration of CO2 in the atmosphere.

So what we see here is the regional climate in the Middle East, and usually terrestrial records, we use them in order to reconstruct precipitation.

With this data, do you go back to the presidents or the heads of these countries and say, 'Here's something that we've just discovered, that your water drought situation could be much worse.'

Do they listen to the scientists that go out and do these...?

We hope that some policy people or environmental organizations will take this into account.

But I think this region is sensitive anyway, and there is a lot of effort by local scientists and by decision makers and environmental organizations to deal with all of the environmental issues and the water stress in this region.

Okay, Yael Kiro, Associate Research Scientist of Geochemistry at Columbia, thanks for joining us.

Thank you very much.

A wood collection doesn't sound very exciting.

In fact, students and faculty at Pennsylvania State University ignored a rare collection of wood for more than 40 years.

But now one professor is dedicating his time to organizing it and unlocking its scientific secrets.

Here's the story.

Dr. Charles Ray has spent the last 3 years updating a spreadsheet.

1,500 entries and counting, each line contains names, dates, and locations.

It's tedious work -- part data entry, part mystery.

A mystery that may have been lost to time, had Ray, a Penn State professor, now writing a blog post about collecting wood.

I got a knock on my office door, and opened the door and it was Dr. Bob Baldwin.

And he said, 'Well, if you like that kind of stuff, I want to show you something.

And he pulls out a set of keys, opens it up, and there is this wood collection stuck in this big walk-in closet.

And I said, 'What is this?'

And he said, 'Well, it's the university wood collection.'

Drawer after drawer stuffed with palm-sized wood samples and some important paperwork that gave Ray, a die-hard Sherlock Holmes fan, his first clue.

Documents trace the collection back to 48 original samples donated in 1909.

More than 100 years later, Ray found more than 5,000 specimens in that closet, the sum of some 30 different collections.

The only real attempt to organize it started in the late 1950s by a Penn State professor named Newell Norton.

And he had been doing that for more than 10 years, as far as I can figure, and he, unfortunately, passed away.

And he was... See right there in the middle?

He was kind of right in the middle of those boxes there when he passed away.

So that was a big problem, is that about half of it then is documented and organized, and the other half is still sort of a mystery that I have yet to solve.

A recent donation added about 6,000 samples, making this one of the largest university collections in the country.

If you take a close look, you'll find some interesting stuff, like a hunk of wood taken from an Egyptian tomb, a slice of something called 'Welwitschia'... It's so rare, Ray thinks it's one of three or four samples available to collectors.

... and a stump found near Ontario that's carbon-dated at 8,700 years.

It's interesting because it was down in the bog and deprived of air and everything else.

It's not petrified.

It's still a piece of wood, woody wood.

In another 3 years, Ray hope to have about 8,000 or 9,000 samples identified and labeled in a searchable database.

Good thing, because after 44 years on the shelf, this collection is more popular than ever.

There are several people around the world that are waiting for me to finish this process so that I can share our list with them so they can see what we've got.

80 years ago -- In fact, 100 years ago when this collection was started, it was really just more about collecting them and having them and not exactly knowing what you're gonna do with it.

With advancements in imaging, computing power and biological testing, samples like these could mean new breakthroughs in genetics and molecular composition.

And if the past is any indicator, that could mean new breakthroughs in medicine.

The Pacific Yew was a poisonous tree, until medical researchers found out that the poison, the Taxine that was in the plant itself, would actually kill cancer cells in breast cancer for women.

Well, the interesting thing about that is if you think about it and say, 'Well, if they can do that for one disease...' Then you think about all these traditional medicines.

It seems like we could synthesize those same chemical compounds to treat a myriad of other kinds of things like that.

It may have started 300 years ago with the first scientist that looked through a microscope and identified the cell organism.

And so in the short-term run, that 300 years looks like, 'Okay, that whole field has been conquered.'

But in reality, what we're seeing now is that it is just beginning to open up and who knows what's gonna come come out of it.

But first things first -- He needs to finish that spreadsheet.


The presence of clouds and shadows mean plants live in a constantly changing world of light.

Researchers have identified that plants can detect shadows.

But how do they do it, and how do they maximize efficiency for capturing sunlight?

Here's the story.

It's not easy being a plant.

♪♪ That's because your world is constantly changing in providing one of the most important things needed to survive -- sunlight.

Watch this time-lapse video.

Once the sun rises, clouds come by.

Shadows move. Sunlight flickers.

The sun sets.

It's clear sunlight isn't always there, and plants use sunlight as energy to make food.

You can think of light as a nutrient, like water.

Plants need water.

Plants need nutrients like potassium and nitrogen.

We add fertilizer to our garden.

They need carbon dioxide.

And plants are competing for these things, and they're competing for light.

Plants need three basic things to live -- water from the soil, carbon dioxide from the air, and energy from the sun.

Plants combine those ingredients to make food in a process called photosynthesis.

It all happens in the plant's cells.

Plants capture sunlight using a compound called Chlorophyll.

Chlorophyll is found inside a structure called a chloroplast.

Photosynthesis converts sunlight into chemical energy which is used to make glucose, or sugar, along with oxygen.

Plants use glucose to live and grow.

They breathe out oxygen.

Now, let's go back to our time-lapse.

It turns out a plant's light-detection system is tied to the efficiency of photosynthesis.

They need to know right now, is it sunny? Is it dark?

Is this a shadow?

Is this flickering light important to me?

And so, in that way, they are smart.

So, this is your typical plant growth chamber.

Researchers at the University of North Carolina at Chapel Hill used a growth chamber to mimic the light changes a plant experiences throughout the day.

That led to the discovery of a protein in the plant called RGS1.

The protein detects changes in light and measures changes in glucose to control how efficiently photosynthesis works.

It knows when something is a shadow and what is a flicker of a light or the end of the day.

It kind of 'knows,' and I'm using 'know' in an anthropomorphic way because remember a plant is sessile, which means it just can't get up and go.

If the sun is too bright, it can't go into the shade like we do.

It has to stay where it's at.

And it has to become, let's say, inefficient at collecting the light because if it were too efficient, it would literally burn up.


And so what we're trying to do is determine how a plant is going to change in response to a change in its environment.

In short, when light changes a plant needs to show restraint.

If a brief shadow forms, then the plant increases the efficiency of photosynthesis.

When the sun comes out of the shadows quickly, the plant will burn up.

The plant needs to determine, 'Is this a shadow or the end of the day?'

It can all be plotted in an equation.

And so we have a plant at some height.

So this is a tiny plant.

And we say, let's let the sun shine a lot of light on the plant.

And then if the sun shines a lot of light on the plant, what we observe is a tall plant.

So what we're going to do is write this all into equations.

And so, in our equation, we have our plant height at the beginning of our experiment, and then we add some light into our plant.

And then we measure how that plant height is going to change.

And then we can plot out the height of the plant as a function of time.

So, what does a plant considered to be a shadow?

The study found any change in light that was longer than 4 minutes was determined to be more than a flicker of light, and the efficiency of photosynthesis was increased.

And my model showed that if that duration is very short, like shorter than 4 minutes, then the plant won't react at all.

The sugar is the signal.

You can think of, you know, we all think of sugars as something important as a nutrient, right?

But it's also a signal.

It's also a signal, just like a hormone is a signal or light can be a signal or, you know, sound is a signal.

The amount of sugar and how it changes in time is also a signal.

And that wraps it up for this time.

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Until next time, I'm Hari Sreenivasan.

Thanks for watching!

Funding for this program is made possible by... ...and contributions to this station.