Science & Medicine

Science makes art

admin — Wed, 09 Aug 2023 02:51:50 +0000

admin Tue, 08/08/2023 - 21:51

“Origami in a Tube” by Di Wang, SM’20. (Image courtesy Di Wang, SM’20)

Summer/23

PhD students’ prizewinning pictures.

In April a trio of PhD students won the highest honors in the 2023 Science as Art contest. Above, the grand-prize winner “Origami in a Tube” by chemist Di Wang, SM’20. And below, second-place winner “Exploring a Microcosm” by materials scientist Pengju Li; and audience favorite “Fuchsia Bone” by geophysical scientist Rachel Laker. Learn about the research behind the images at mag.uchicago.edu/scienceasart2023.

“Exploring a Microcosm” by Pengju Li. (Image courtesy Pengju Li)

“Fuchsia Bone” by Rachel Laker. (Image courtesy Rachel Laker)

Science & Medicine

Photography

Science

Clean water

rsmith — Wed, 09 Aug 2023 02:51:32 +0000

rsmith Tue, 08/08/2023 - 21:51

Maureen Searcy

The Core

Summer/23

How to kill pathogenic bacteria, viruses, and protozoa in four easy steps

A class called Are We Doomed? Confronting the End of the World, taught virtually in Spring 2021 by astrophysicist Daniel Holz, SM’94, PhD’98, and sociologist James Evans, asked College students in the midst of “unprecedented times” to consider existential threats. Topics included nuclear war, climate change, disinformation, and—of course—pandemics.

For the final project, students were asked to create an object that might exist 30 years in the future. “Recipes for Disaster,” by Fatou Dioum, AB’23; Tim Granzow, SB’22; Shane Kim, AB’23; and Grace Wagner, AB’23, SB’23, is a “beginner’s survival guide to coping with the end of the world” and includes instructions for obtaining the most vital resource for life: clean water.

You will need

A clean cloth or coffee filter
Salt
Water
Containers with covers
A pot
Solar cooker or fire or stove

How to purify water

Step 1

If water is cloudy, let it settle. Then filter it through a clean cloth or coffee filter.

Step 2

Bring water to a rolling boil for at least one minute in a pot.

Step 3

To improve the flat taste, add a pinch of salt for each quart or liter of water.

Step 4

Let water cool naturally. Store in clean containers with covers.

Source: WHO, 2015.

Science & Medicine

Recipe

Are we doomed?

rsmith — Wed, 09 Aug 2023 02:51:32 +0000

rsmith Tue, 08/08/2023 - 21:51

Earth warming by just a couple of degrees can make some areas unsuitable for habitation or agriculture. (istock/Bim)

Maureen Searcy

The Core

Summer/23

UChicago scholars contemplate the end of the world.

It’s reasonable to assume that a class called Are We Doomed? Confronting the End of the World, taught virtually in Spring 2021, might have been motivated by COVID-19.

Yet astrophysicist Daniel Holz, SM’94, PhD’98, and sociologist James Evans had to scramble to add material on the pandemic. Presciently, they had developed the course (part of the College and the Franke Institute’s Big Problems program on matters of global or universal concern) before the emergence of SARS-CoV-2. More than 75 College students, just as presciently, had enrolled.

Evans, the director of UChicago’s Knowledge Lab, and Holz, the science and security board cochair of the Bulletin of the Atomic Scientists, didn’t plan the course with an answer in mind. Nor was the goal “to give the complete accounting of every way that civilization can end,” says Holz. “The main task of the class is not so much in the details as to build awareness that there are existential threats. We should not take the existence of civilization for granted.”

Informed by Holz’s work with the Bulletin, the course covered “headline threats” of nuclear war, climate change, and, increasingly, disinformation. “Then there are a bunch of others that are waiting in the wings,” Holz says, like the rise of artificial intelligence and pandemics, which ended up taking center stage.

Each class featured a guest speaker (scholars from UChicago and beyond) and assignments including articles; movies such as Dr. Strangelove (1964); and novels, including Albert Camus’s The Plague (1947). For the final project, students, alone or in groups, created “one modest object that belongs to this future world.”

The course served as a sort of proving ground for what Holz calls the Existential Risk Laboratory. Still in the planning stages, XLab would help students learn about the risks covered in Are We Doomed? and how they might mitigate these risks—regardless of their career paths.

Viewing the future through the lens of existential risk could empower them, but “one of the big challenges in this is to inform people without leaving them despondent,” says Holz. Based on their final projects—including a “recipe” for clean water—many students seem to have emerged from the class with hope.

Holz and Evans aren’t the only UChicago scholars whose work leads them to think and teach about existential threats. Throughout the University, academics in a range of disciplines are confronting the possibility of the end of the world: how we define it, how we can stave it off, and how we might rebuild after catastrophe.

But first, what might doomsday look like?

Hollywood loves an annihilation-by-asteroid arc, but planetary scientists aren’t worried. (istock/MARHARYTA MARKO)

Humanity is no more

The Cretaceous-Tertiary Mass Extinction event that wiped out the dinosaurs and half of all species 65 million years ago was probably caused by an asteroid or comet hitting Earth. A sensational—and highly marketable—prediction is that the human species might meet the same fate.

Planetary scientist Fred Ciesla isn’t worried; scientists continuously monitor for approaching space rocks and have practical solutions. Last fall NASA scientists intentionally slammed the Double Asteroid Redirection Test (DART) spacecraft into a nonthreatening asteroid moonlet and changed its orbit by 33 minutes. “That’s all it would take,” says Ciesla. If we saw an asteroid that posed a threat in a century, “a little nudge now would, over the course of a hundred years, lead to it being no more than a distant passerby.”

In his role at the Bulletin of the Atomic Scientists—the independent organization founded in 1945 by UChicago scientists that sets the hands of the Doomsday Clock—astrophysicist Daniel Holz is more concerned that nuclear war is humanity’s ultimate threat. This year the Doomsday Clock was set to 90 seconds to midnight, ten seconds closer than last year—the closest it has ever been. Concerns about the war in Ukraine dominated the decision, says astrophysicist and former Bulletin science and security board chair Robert Rosner.

Those old enough to remember the Cold War were steeped in the consciousness of a looming World War III. In the 1950s Americans built backyard bomb shelters, and into the 1980s movies like The Day After or WarGames, both released in 1983, shaped perceptions of an imminent nuclear threat. Holz would sometimes start public lectures by asking who was worried about nuclear Armageddon: “The only people who ever raised their hands were people who had been alive during the Cuban Missile Crisis.”

The danger of nuclear war, beyond the immediate destruction from bomb blasts, is twofold, says Rosner. Radioactive materials would contaminate agricultural land and, even more perilously, a war could trigger a nuclear winter and mass famine. “If you generate huge fires, especially in urban settings, and you put enough soot in the atmosphere to block sunlight sufficiently, you kill agriculture all over the entire world,” he explains.

“We’re arguably at a unique time in history,” says Holz. The ability for global destruction via nuclear war or rapid climate change is an extremely recent development in the time frame of human civilization. A thousand years ago, a hundred years ago, he says, we couldn’t have wiped out all of humanity through our own actions.

But would a third world war extinguish every human life? “That would require a truly concerted, conscious effort,” says evolutionary biologist and paleontologist David Jablonski. “As a biological species, we’re hard to kill. We see from past extinction events in the fossil record that one of the factors that most promotes survival in the face of perturbations is broad geographic range, and we have people living from McMurdo Sound in Antarctica to high up in the Himalayas.”

A genetically engineered superbug could lead to extinction, but human immunological variability makes that chance slim. What we can do—with great competence—is destroy our own quality of life. That’s what he’s most concerned about: “not the extinction of the species but the misery.” That requires its own set of countermeasures.

Climate and weather are distinct but linked: climate change increases the intensity and frequency of severe weather. (istock/RamonBerk)

Humanity marches on in misery

Climate change is a truly global threat already demonstrably affecting people and all forms of life. But the planet warming by two degrees won’t kill our species, says Elisabeth Moyer, an atmospheric scientist and coprincipal investigator of the Center for Robust Decision Making on Climate and Energy Policy (RDCEP). The Center—a partnership between UChicago and several universities and national laboratories—was established in 2010 to address climate change and energy supply challenges and to help policy makers deal with “deep and pervasive uncertainty.”

Global warming will, however, flood coastlines, intensify severe weather, and increase heat waves, droughts, and wildfires. A couple of degrees can make some places unsuitable for habitation or agriculture. Some areas will be able to adapt, but resources are “appallingly unevenly distributed,” says Jablonski, who teaches a College class on biological evolution.

Populations with no recourse will become “climate refugees,” says Moyer. Climate change “disrupts everything we do in ways that we’ve not really even considered yet.”

One method of mitigating climate change is simple (but not easy): reduce CO2 emissions. “We had this phase where we burned a lot of fossil fuels, and that helped us build our civilizations,” says Moyer. “That was what we needed to do, and now we need to stop doing that because we have other technology.”

Such a transformation won’t be fast because our energy infrastructure is enormous, says Moyer. One of her projects brings together scientists and historians to analyze how our energy system has evolved over 200 years, and to help people see how those changes happened—in hopes that “the incremental steps we might take going forward” don’t seem so daunting.

In the past decade, “we’ve undergone an energy transition that is as significant as any in history,” she says. “You just didn’t notice because it changes the way your electricity is made, but you plug the same appliances in.” Yet more than half of the coal mines in the United States have closed, their fuel replaced by gas, wind, and solar power.

Historical context can help us “not just wring our hands about existential threats,” says Moyer, or fixate on an imaginary impossible solution, but instead treat “supposedly distant, complicated, and large-scale problems realistically and practically.”

Looking to the past offers perspective on the threat of disease, as well—particularly when we are still in the midst of a global pandemic. People living through the Black Death during the mid-1300s truly believed it was the end of the world, says Michael Rossi, a historian of medicine. They “would write things like, ‘if there’s anyone even left to read this, this is my account.’”

Plague is accompanied by radical social breakdown, says Rossi. “You almost always get accounts of people being unable to maintain social ties, whether it’s not enough healthy people to bury the dead or perform death rituals.” The instability leads to further hardship, such as starvation.

“We saw mild—and less mild—forms of this during COVID,” he says. In the United States, some communities have continued to experience higher rates of morbidity and mortality, the “disease exposing existent cracks in our social structures that we knew were there.”

Rossi teaches a course on ancient medicine. He hopes his students learn that “the world in the past was very much a matter of rich decision-making rather than just bumping around in the dark,” he says. “Or conversely, that we’re also bumping around in the dark. We just don’t know it.” He also hopes students gain a sense of optimism, with a tinge of humility, learning that they can bend history through vigilance and action.

While Rossi looks back, Holz looks forward: “COVID was just a baby practice pandemic compared to what might be in store” and the misery it could bring. And Jablonski adds, “Clearly, we’ve had rubbed in our face how badly we handle emerging diseases.” America’s—and the world’s—response to COVID was influenced by scientific, cultural, social, and emotional factors, but it was also complicated in a new way: by misinformation and disinformation spread by the internet.

Plague is accompanied by social breakdown—well documented during the Black Death and seen again during COVID. (istock/egal)

Humanity on hard mode

The path from nuclear war to nuclear Armageddon is clear, but it’s not as easy to extrapolate the danger of inaccurate misinformation and intentionally misleading disinformation. Holz calls disinformation a “threat multiplier”—an added dimension of difficulty for a society trying to save itself.

“It undermines rational discourse,” says Holz. “We have to agree on facts, on basic aspects of the world around us” to have any hope of making progress. We must agree that the earth is round, climate change is happening, and COVID exists before we can even consider addressing more nuanced threats.

Moyer has worked in climate science for two decades, so she’s no stranger to disinformation. Climate change denial makes sense to her: the forces driving it can be traced back to the industries and people whose profits suffer from energy transformation efforts. But the goals of those who deny COVID, for instance, are broader—harder to pinpoint and thus harder to combat. “That to me is the scariest thing right now in our society.”

“It gets fundamentally in the way of fixing anything,” says astrophysicist Rosner, who cites disinformation as his topmost concern. “There’s an epidemic of skepticism of expertise and science,” and it infects everything, Rosner says. “The internet has really made it worse, and we don’t know how to regulate the internet.” He is particularly worried about a pending lawsuit in federal court that attempts to classify mis- and disinformation as political speech protected by the First Amendment.

A 2019 article in the Bulletin of the Atomic Scientists called misinformation and disinformation “cyber-enabled information warfare”—both a multiplier of existential threats and a threat in its own right. “Corruption of the information ecosystem,” it reads, poses “the possibility of a global information dystopia, in which the pillars of modern democratic self-government—logic, truth, and reality—are shattered, and anti-Enlightenment values undermine civilization as we know it.”

Ciesla, who teaches the College class Earth as a Planet: Exploring Our Place in the Universe, says that his job has changed over the years to include confronting mis- and disinformation.

In addition to teaching planetary science, he also focuses on information literacy: the ability to seek, evaluate, use, and create information effectively—a skillset immeasurably complicated by the ease with which anyone can post anything on the internet. His message goes beyond literacy to understanding how our decisions based on information can affect other people, and how other people’s decisions affect us, he says: “It’s not just us working, living in isolation.”

Read “What Then?”—a collection of interviews with faculty in the humanities and social sciences about the need for radical imagination and, above all, the need for hope.

Spilled coffee … fundamental truths

rsmith — Wed, 09 Aug 2023 02:51:32 +0000

rsmith Tue, 08/08/2023 - 21:51

A few examples of Nagel’s high-speed physics photography. Selective Withdrawal (top) and Breaking Away: Glycerol in Oil (near right) are in the Smart Museum of Art’s permanent collection. (Photos courtesy Sidney Nagel/Smart Musem of Art)

Louise Lerner, ABʼ09

The Core

Summer/23

Sidney Nagel receives the “lifetimeachievement Oscar of physics.”

Physicists have a reputation for caring about the grandest questions: the formation of the universe, the collisions of black holes, the nature of time and space.

But Sidney Nagel was also curious about modest things. Why a spill from a coffee cup forms a ring instead of a spot. How a raindrop stretches and falls from an overhang. The shifting of grains of sand. He’s spent nearly 50 years looking into these everyday phenomena.

In January Nagel, the Stein-Freiler Distinguished Service Professor of Physics, accepted the 2023 American Physical Society Medal for Exceptional Achievement in Research. The award, sometimes called the lifetime achievement Oscar of physics, recognizes “contributions of the highest level that advance our knowledge and understanding of the physical universe in all its facets.”

Nagel is the second recipient of the award from UChicago. His longtime colleague Eugene Parker (1927–2022) was recognized in 2018 for contributions to space physics.

(Photography by Sidney Nagel/courtesy Smart Museum of Art)

Nagel was one of the first to do research in the field of physics known as soft matter. Decades ago soft matter was not only little known, but disdained; today it is a primary focus in physics. “The thing that makes you a candidate for a prize like this is that you change a field,” says Thomas Witten, professor emeritus of physics. “Sidney changed many things.”

Nagel and his collaborators ran endless experiments to figure out why spilled coffee forms a ring and why grains of rice or coffee in a container pack more tightly when shaken. They took high-speed photographs of droplets separating and discovered a hitherto unseen world of physics. They developed the mathematics to explain how the breakup of ordinary liquids mimics features found not only in other materials but (at the largest scale) in black holes as well.

They also introduced the importance of “jamming,” the phenomenon that turns loose grains into a rigid solid when squeezed together—opening up a new line of intensive research across several fields.

Through it all, a theme emerged: “The idea that disorder and inequilibrium are crucial,” Nagel says.

The classic approach to physics is to envision the simplest system to find fundamental truths. For example, physicists often cool down their experiments to near absolute zero to remove confounding variables like temperature and the disorder that comes with it.

“But the thing is, most systems are not actually in equilibrium,” Nagel says. “The atmosphere is not. People are not. In fact, if you think about it, biology is set up to keep us from reaching equilibrium.”

Nagel wondered, “Is there an epitome of disorder, and if so, what are the principles that govern it?”

Nagel’s photograph Breaking Away: Glycerol in Oil is in the Smart Museum of Art’s permanent collection. (Photography by Sidney Nagel/courtesy Smart Museum of Art)

Nagel’s findings have laid the foundation for a deeper understanding of our world, as well as for applications in biology, materials science, and robotics. “The impact of Sid’s work goes far beyond any one particular phenomenon or any particular subfield of science, because the basic principles he uncovered are so widely applicable,” says Heinrich Jaeger, the Sewell Avery Distinguished Service Professor of Physics, and a longtime friend and collaborator. (At an annual event for the public called Physics with a Bang!, Nagel and Jaeger explode balloons, launch bottles across the room with gas, and blow smoke rings with garbage cans.)

Nagel’s approach is also known for another characteristic: an appreciation of beauty in the world. His office is lined with images taken of experiments, often in black and white, that showcase the perfect curve of a droplet about to fall or the sly lines of water and oil sliding past each other. Several of these are part of the Smart Museum of Art’s permanent collection. “The phenomena themselves have an aesthetic quality,” Nagel says, “that I don’t think of as separate from physics.”

Science & Medicine

Photography

Faculty

Cryptic kingdom

rsmith — Tue, 02 May 2023 22:14:07 +0000

rsmith Tue, 05/02/2023 - 17:14

(Illustration by John Jay Cabuay)

Maureen Searcy

The University of Chicago Magazine

Spring/23

Matthew Nelsen, PhD’14, explores the mysteries of fungi.

Scientists have formally described about 120,000 species of fungus. There might be millions more out there, but fungi are largely hidden. When you think about fungi, you might picture showy mushrooms, but those are just the fungal version of fruit, sprouting when it’s time to reproduce. Most of the time, fungi live underground or inside logs. At the Field Museum, mycologist and evolutionary biologist Matthew Nelsen, PhD’14, is working to bring these obscure organisms to light. His comments have been edited and condensed.

A fungus is not an animal, and it’s not a plant. What is it?

Its own thing! It’s its own kingdom. But yeah, it’s like, where do these go? They’re not running around like animals; they generally seem to just sit there like plants. Here at the Field Museum, I’m in the botany section, but when we look at DNA evidence, we can see that fungi and animals are each other’s sister groups, essentially. In the mycological community, there’s a big push to recognize fungi as another dimension of biodiversity, especially in the context of conservation.

What specific aspect of fungi fascinates you?

How fungi have evolved to form different types of long-standing partnerships—mutualism with some organisms, parasitism with so many others. What’s the underlying genomic basis for this ability? I work a lot with lichen—which are organisms made from symbiotic fungi and algae—but I’ve been branching out into the partnerships between fungi and plant roots, and I’m in the very early stages of studying a group of fungi that attacks other fungi and different invertebrates.

How do plants and fungi help each other out?

Nearly all plants form deeply rooted evolutionary partnerships with fungi, which helps the plants access nutrients and water that they aren’t very good at getting on their own. So the plant can grow bigger and faster, and in return, the plant feeds the fungus sugar, which it can’t make on its own. This partnership is thought to extend back to when plants first evolved on land. There are 400-million-year-old fossils showing some of these partnerships.

Fungi are well known to provide food, medicine, psychedelics. What are some lesser-known benefits of fungi?

Farmers are starting to recognize the worth of fungus-plant partnerships. The timber industry can also benefit from this knowledge. People used to take a tree from one part of the world and plant it in another region, and it wouldn’t grow very well. They realized you need to take some soil with it, some of the microbial community to maintain these partnerships. But now mycologists are starting to recognize that fungi are growing in places they weren’t before, and they can disrupt the ecosystem.

The video games and television series The Last of Us ascribe the apocalypse to an unspecified “zombie” fungus called Cordyceps. Does this help or harm fungi’s reputation?

I’m torn. I really like that it’s popularizing fungi and getting people’s attention, but it’s unfortunate that it’s from a detrimental perspective. I hope that we can still leverage that to draw people in to learn what’s real and what’s fiction.

Zombie-ant fungus—Ophiocordyceps unilateralis—which inspired The Last of Us, is real. How does it work?

It’s thought that the spores land on an ant and the fungus grows through its exoskeleton. Eventually it spreads through the ant’s body, decomposing it from the inside, and the insect starts acting strangely. It might convulse or wander randomly.

Ultimately the fungus exhausts its food supply and will need to move on. So it makes the ant climb up a small shrub, pinch onto a big leaf vein with its mandibles, and hang upside down, where it dies. A long fungus stalk grows out of its head, and the spores rain down on other ants below. This has been going on for at least 48 million years. There’s a fossil leaf with these bite marks in it.

How does the fungus control the ant?

You can see the fungus growing through the muscles and around the brain, but it doesn’t appear to be infecting the brain itself. The fungus seems to be releasing chemicals, some of which are related to those that cause convulsions in humans, that may affect the ant’s behavior.

The Last of Us implies that infected people are psychically connected to each other and to a vast underground network of the fungus. Does that have roots in reality?

Some fungi do form vast underground networks, but not Cordyceps. There’s this tree parasite nicknamed the Humongous Fungus, a species of honey mushroom from a group called Armillaria, and they form huge colonies. The first one was found in the Upper Peninsula of Michigan, and now they found an even bigger one in Oregon. It’s estimated to be a thousand years old and miles across.

There are also fungi that form mutualistic relationships with roots that can connect multiple trees together. This underground network is called the Wood Wide Web. There’s an idea that maybe sugar and chemical signals could travel from one tree through the fungus to another tree, but in the past few weeks there’s been a lot of activity calling that idea into question, asking how much data we really have to support the hypothesis.

Can zombie-ant fungus infect humans?

We’re very warm, and a lot of these fungi can’t survive in environments that hot for that long. Our body temperature proves to be a barrier for a lot of fungi.

Could climate change drive its evolution enough to overcome that barrier?

There are protective factors other than body temperature. We have a really good immune system. We are constantly breathing in microscopic spores around us, and most of us don’t get sick because our bodies fight off the fungus.

Will the COVID-19 pandemic increase our vulnerability to fungal infections?

There’s been a lot of activity in the medical mycological world trying to look at this topic, because having a compromised immune system does open you up to infections you’d generally be able to fight off.

What fungal infections pose the most danger to us?

I’m not a medical mycologist, but I know of a few nasty ones, like Candida auris, which has been going around hospitals quite a lot. Coccidioides and Pneumocystis aren’t good—they get in your lungs. Less aggressive ones like athlete’s foot, ringworm, or nail fungus aren’t super terrible.

But they take forever to treat. Why is it so hard to cure fungal infections in humans?

Because we share a lot of biochemical similarities with fungi. When we’re trying to kill a fungal cell, we need to make sure we’re not killing our own as well. We’re far less similar to bacteria.

Why don’t more people study fungi?

They’re not as endearing as things with big eyes and lots of fur. I grew up kind of thinking fungi were gross. It varies across cultures around the world, but a lot of folks probably feel like I did. That’s something I’m trying my best to change.

Science & Medicine

Fungus

Graduate alumni

Division of Biological Sciences

Interview

UChicago research roundup

rsmith — Tue, 02 May 2023 22:14:07 +0000

rsmith Tue, 05/02/2023 - 17:14

(Photography by Corleto Peanut butter / Unsplash)

Maureen Searcy

The University of Chicago Magazine

Spring/23

Peanuts, pollution, plant energy, and a precise picture of the universe.

Gut reaction

Certain gut bacteria can help protect against food allergies by blocking antigens, such as those found in milk or peanuts, from entering the bloodstream. A study led by UChicago immunologist Cathryn Nagler, published online December 22 in Nature Biomedical Engineering, found that delivering the chemical butyrate, produced by a certain type of gut bacteria, directly to the intestines of mice with a peanut allergy reduced their allergic response. The delivery also allowed the beneficial bacteria that make the chemical to flourish. But the solution couldn’t be just to make a butyrate pill; the chemical has a foul odor and taste and gets absorbed in the stomach before it can reach the intestines, where it’s needed. So Nagler teamed up with UChicago molecular engineer Jeffrey Hubbell to design polymers called micelles to carry a payload of butyrate to the intestines before releasing it. This technology could put once-deadly snacks back on the menu.

Poverty costs

Growing up in a low-income neighborhood has been associated with lapses in child development, which can emerge as early as six months—well before children start school. But it’s not clear exactly how neighborhood poverty leads to these gaps. A study led by UChicago sociologist Geoffrey Wodtke, published online November 30 in Science Advances, investigated whether early exposure to air pollution—which disproportionately affects lower-income areas—plays a role. The team analyzed data from a national sample of American infants matched with their estimated exposure to more than 50 air pollutants monitored by the EPA that are known or suspected to harm the central nervous system. They found that about a third of the decline in cognitive abilities associated with neighborhood poverty could be attributed to increased exposure to air toxins in infancy. The research suggests that improving environmental health may promote better outcomes for children.

Fueled by nature

Plants efficiently convert water and carbon dioxide into sugar using the power of the sun, offering a model for how humans can create our own energy sources—and maybe one day replace fossil fuels. But nature’s complex machinery isn’t easy to copy, and sugar can’t meet our energy needs. A team led by UChicago chemist Wenbin Lin has brought us one step closer to a viable energy alternative by developing an artificial photosynthesis system that creates methane and is exponentially more productive than previous artificial systems. Described in a paper published online November 10 in Nature Catalysis, the “artificial enzyme” that drives the reengineered photosynthesis is based on crystalline compounds called metal-organic frameworks arranged in a single layer to maximize surface area where the chemical reaction occurs. Then the team made their artificial enzyme more like natural enzymes than previous designs did by adding amino acids, which increases the efficiency of the photosynthesis.

Starchart

In an instant, roughly 13.8 billion years ago, all matter in the universe sprang forth and spread out in an explosive expansion. The extremely hot, dense matter cooled and clumped together—into planets, stars, galaxies—as the universe expanded, a process that is still happening. By mapping matter today, cosmologists can study the evolution of the universe. A recent analysis combining data from the Dark Energy Survey Collaboration, which maps distant galaxies, and the South Pole Telescope Collaboration, which searches for leftover radiation from the big bang, has produced one of the most precise maps of the universe to date. The new map shows that matter isn’t as “clumpy” as cosmologists would expect based on current models, suggesting there may be something missing from how they think the universe is evolving. The project involved more than 150 researchers, several from UChicago and Fermilab, and was published online as a three-article set January 31 in Physical Review D.

Science & Medicine

Faculty research

Quick Study

Connect with slime mold

rsmith — Tue, 02 May 2023 22:14:07 +0000

rsmith Tue, 05/02/2023 - 17:14

It’s alive! The Human Computer Integration Lab’s novel smartwatch is activated by an organism called Physarum polycephalum. (Photo courtesy Jasmine Lu)

Maureen Searcy

The University of Chicago Magazine

Spring/23

A living smartwatch tracks the bond between people and their devices.

Do you have a smartphone in your pocket or a smartwatch on your wrist? For many of us, our devices are constant companions—only to be ditched when a newer model is released. In 2021 a record 63 million tons of electronic waste were discarded worldwide, of which only 17 percent was recycled. But what if we developed emotional relationships with our devices like we do with our pets, wondered Jasmine Lu. Would we be so quick to abandon them?

Lu is a computer science PhD student in assistant professor Pedro Lopes’s Human Computer Integration Lab, which focuses on engineering interactive devices that integrate directly with a user’s body. Lopes’s research is a more immersive take on human-computer interaction, a field that explores the interfaces between people and technologies.

To probe the potential for a more caring bond with our electronics, Lu designed a smartwatch integrated with a living organism: a slime mold. The device, which tells time and monitors heart rate, works only when the slime mold is healthy. The wearer must care for the device, like a living Tamagotchi—the Japanese virtual pets popular in the ’90s. Lu didn’t set out to reimagine the egg-like toy, but after creating the slime mold watch, she recognized the similarities to her childhood virtual pet. She would feed it in the morning and bring it to school, hooked on her belt loop, she says. “I treasured it.”

Why a slime mold? Despite the name, it’s not like other types of mold, explains Lu. Slime molds are now known to be part of the protist kingdom—a diverse collection of mostly single-celled organisms distinct from fungi, plants, animals, and bacteria. The species Physarum polycephalum was chosen because it can rapidly grow toward food sources, which is how it is able, curiously, to solve mazes. Nicknamed “the blob,” the species is also resilient, able to go dormant when starved and to be revived even years later.

The slime mold lives in a transparent enclosure on the watch, and the wearer must give it oats and water on a regular schedule. When properly cared for, the slime mold will grow across a channel to reach oats on the other side of the enclosure, forming a living wire that conducts electricity and activates the device. (Electricity travels through the slime mold, but the current is low enough that the team didn’t observe any harm to its body; it continued to thrive, says Lu.)

The two-week study involved five participants and was split into phases: “caring” and “neglect.” Throughout the process, the participants kept a diary of the care they provided, the slime mold’s condition, and their own reflections. They were interviewed after each phase.

For the caring phase, they were asked to wear the watch for as much of the day as possible, watering the slime mold twice a day and feeding it oats every other day. All participants noted a sense of connection with the watch, and four described it as a little friend or pet. One named her slime mold Jeff. (The participants sometimes talked about the slime mold as a separate entity rather than part of the device, something Lu and Lopes hope to change with an updated design.)

One woman was reminded that her device had a life-form inside by its earthy smell and associated the healthy slime mold’s bright yellow color with happiness. Another linked the watch’s needs to her own: whenever she ate, she would check the slime mold. Yet another recounted how she was sick during part of the care phase, and her partner fed her oatmeal. “She started calling me her slime,” wrote the participant, because “we were eating the same stuff.”

The participants were then told to withhold water and food. Unsurprisingly, all five mentioned how much easier the second phase was; they felt relieved and disconnected. But each participant also felt sad or guilty while neglecting their slime mold. One woman who had eagerly shown off her living watch felt anxious about having to explain the slime mold’s neglected state. While the dried-out slime mold was technically dormant, many participants referred to it as dead.

The team collected the watches after the experiment, but in the exit interview, they asked hypothetically, “How would you dispose of the watch?” Responses included: toss the watch and keep the slime mold; sell it; and give it to a friend. “If you really couldn’t take care of a pet anymore,” said one of the participants, “you would try to rehome it.”

All participants identified as women, which was not a deliberate experimental design choice. Lu speculates there may have been some self-selection—many women grew up with toys where “caretaking is the central modality that they’re expected to engage with.” Tamagotchis were aggressively marketed toward girls, and four of the five participants happened to have direct experience with virtual pets. But “it was a small set of people,” says Lopes, “so you can’t generalize too much.” In the future, says Lu, “it would be interesting to explore this from a gendered perspective.”

Of course, slime mold watches will likely never catch on like Tamagotchis, nor was Lu suggesting with this research that biological devices are the practical solution to e-waste. Rather, exploring interactions between people and their living technology might teach engineers how to center a sense of care in their interactive designs. If engineers could make it easier to repair rather than replace devices, for instance, people with less computing or electronics literacy “might feel more empowered,” says Lu—more comfortable learning how devices work and exactly what they’re doing.

Lopes compares repairing your own device to people learning to bake bread during the pandemic. You could buy a mass-produced loaf at the store, “but folks are discovering some deeper connection by making their own.” You could buy the latest iPhone, but if you repair or upgrade the one you already have, it’s no longer the sole creation of Apple, says Lopes. In some ways, “it becomes partly yours.”

Consumer devices “are made so that you trash them, instead of engaging with them,” Lu told UChicago Computer Science News. “So I definitely think there is a design takeaway of focusing on this aspect of caring for devices instead of just consuming them.”

Science & Medicine

Computer science

Human Computer Integration Lab

The T. rex of its time

admin — Wed, 08 Feb 2023 14:52:52 +0000

admin Wed, 02/08/2023 - 08:52

A Whatcheeria skull in the Field Museum’s collections, which include all Whatcheeria specimens unearthed thus far. Its fossils were discovered in a limestone quarry near What Cheer, Iowa. (Photography by Kate Golembiewski/Field Museum)

Maureen Searcy

The Core

Winter/23

An ancient Iowan superpredator grew up fast.

Whatcheeria—a prehistoric superpredator that lived several hundred million years before SUE the T. rex—was a six-foot-long lake-dwelling creature. “In life, it would probably look like a big crocodile-shaped salamander, with a narrow head and lots of teeth,” says UChicago and Field Museum doctoral student Ben Otoo, SM’19, coauthor of a new study in Communications Biology. “If it really curled up, probably to an uncomfortable extent, it could fit in your bathtub, but neither you nor it would want it to be there.”

Otoo is part of a team studying the primitive tetrapod (four-limbed creature). Because the Field Museum has so many specimens—about 350—the team can study the animal at different life stages. Many modern reptiles and amphibians grow slowly and steadily from birth to death, but Whatcheeria was different. New research shows that it grew rapidly in youth and leveled off in adulthood, like most mammals and birds. This surprising revelation can help researchers better understand how tetrapods—including humans—evolved.

Science & Medicine

Fossils

UChicago Creatures

It was written in the stars

admin — Wed, 08 Feb 2023 14:52:52 +0000

admin Wed, 02/08/2023 - 08:52

Subrahmanyan Chandrasekhar spent 27 years working and living on the grounds of Yerkes Observatory in Williams Bay, Wisconsin. (UChicago Photographic Archive, apf1-01654, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library)

Maureen Searcy

The University of Chicago Magazine

Winter/23

Astrophysicist Subrahmanyan Chandrasekhar (1910–95) illuminated stellar evolution.

Subrahmanyan Chandrasekhar—child prodigy, predictor of black holes, Nobelist, and UChicago professor for nearly 60 years—often distilled his life into two sentences: “I left India and went to England in 1930. I returned to India in 1936 and married a girl who had been waiting for six years, came to Chicago, and lived happily thereafter.”

Chandrasekhar is best known for the earliest part of his career, when he determined the fate of massive stars and was betrayed by a mentor. Yet he spent the next six decades making equally influential breakthroughs in stellar structure and dynamics, and training a new generation of astrophysicists. He also faced discrimination and alienation, elided from the fairy-tale ending he liked to recount.

Chandra, as he was known, was born in 1910 in Lahore—then British India, now Pakistan—the third of 10 children. In Chandra: A Biography of S. Chandrasekhar (University of Chicago Press, 1990) his biographer Kameshwar C. Wali, a UChicago physicist in the late ’60s, describes him as a mischievous child with an early aptitude for math.

Chandra didn’t attend traditional school until he was 11; prior to that he was taught by tutors and allowed to follow his intellectual interests. Regarded as a mathematics prodigy, he entered Presidency College in Madras at 15, where he gravitated toward physics. His precociousness recalled that of his uncle C. V. Raman, who went on to win the 1930 Nobel Prize in Physics for demonstrating quantum effects in the scattering of light.

At 17 Chandra spent the summer working in his uncle’s lab, where early on he broke a crucial piece of equipment. Experimental physics was not in his future. But he befriended one of Raman’s colleagues, who introduced him to the work of Arnold Sommerfeld, one of several theorists transforming physics through quantum mechanics. This group included Ralph H. Fowler, who helped Chandra publish a paper in the Proceedings of the Royal Society of London, the first of about 400 articles—and numerous books—in his lifetime.

Near the end of his undergraduate studies, Chandra was offered a special Government of India scholarship to study in England. In 1930 he set out for the University of Cambridge. While at sea on one leg of the voyage, reading physics publications to pass the time, the 19-year-old Chandra famously arrived at his Nobel-winning insight.

Sixty-eight years earlier, astronomers had first observed a white dwarf: the small, hot, extremely dense remnant left after a star burns through its fuel. But it didn’t make sense—such an object shouldn’t be able to resist its own gravity and should have collapsed. Fowler, Chandra’s soon-to-be PhD adviser at Cambridge, solved the puzzle using quantum theory to explain the phenomenon.

Chandra’s maritime math took Fowler’s explanation a step further, calculating that the physics stabilizing ultra-dense white dwarfs worked only up to a point. Over a certain mass, a dying star in fact could not overcome gravity and would collapse into some incomprehensibly dense object (what we now call a neutron star) or maybe even an infinitely dense point (a black hole). That upper boundary, later named the Chandrasekhar limit, is about 1.4 times the mass of our sun.

His work built on Fowler’s research and that of Cambridge astronomer Arthur Eddington, who believed all stars were destined to become white dwarfs. As Chandra refined his calculations over four years in England, Eddington regularly dropped by to see how the work was progressing. When Chandra was ready to present his findings at the Royal Astronomical Society meeting in 1935, Eddington arranged for Chandra to have double the customary 15 minutes and scheduled his own presentation to immediately follow. When Chandra finished, Eddington ridiculed the young astrophysicist’s conclusion, publicly humiliating him.

In private, some colleagues reassured Chandra, but it would be more than 20 years before his limit was widely accepted. In one of his final interviews, he reflected on the incident: “Suppose Eddington, instead of finding that I was wrong, had instead said, ‘What you have done is very important.’ … Given Eddington’s reputation, he could have made me instantly a very well-known person.” But enjoying such early prominence, he said, could have diverted his research. “You lose your motivation to continue doing science.”

“The Eddington factor had the effect of closing the doors in England,” writes Eugene Parker, Chandra’s UChicago colleague and the discoverer of solar wind. (Parker wrote a biography for the National Academy of Sciences after Chandra’s death from heart failure in 1995.) His father suggested returning home, but Chandra “found himself increasingly out of sympathy with the political nature of academia in India.”

Chandra was invited to lecture for a few months at Harvard in early 1936. While he was there, the director of UChicago’s Yerkes Observatory, Otto Struve, PhD’23, offered him a position as research associate, with the promise of a tenure-track appointment at the University after a year. Harvard also offered a faculty position, but Struve was doing something new. He was recruiting “theoretical astrophysicists, a very rare breed in the United States” in those years, writes one of Chandra’s graduate students, Donald Osterbrock, PhB’48, SB’48, SM’49, PhD’52, in a brief history of Chandra’s time at Yerkes. Struve was merging theory and observational astronomy; he was also recruiting two of Chandra’s friends.

Against his father’s wishes, Chandra agreed to settle across the pond. But first he returned to India to see about a girl.

Chandra had been corresponding with his future wife for six years. They had been immediately drawn to one another, but their long-distance courtship was filled with uncertainty.

Chandra first met Lalitha in an honors physics course at Presidency College. Born Doraiswamy Lalithambal, she came from a family of educated women—uncommon in India at the time. Early marriage was out of the question for Lalitha and her female siblings and cousins. She would earn her master’s in physics first. In an autobiographical essay, she describes her love of physics as stemming from her interest in Marie Curie and the excitement in India over C. V. Raman’s Nobel Prize.

Lalitha had “noticed with interest the young man with a crew cut, always sitting behind her in the second row,” writes Wali. She asked him if she could see his laboratory record book, and he readily agreed. They shared the notebook from then on; at a party, Chandra gave her a rose. Days before he left for England, Chandra visited Lalitha’s home with books she’d requested; they sat in awkward silence until her family joined them.

At Cambridge he ventured an apprehensive letter: “Dear Miss Lalitha, I was for a long time hesitating whether I should allow myself the liberty of writing to you particularly as I am anxious not to displease you in any manner possible.” Encouraged by her swift reply, he wrote back without delay. Formalities turned to “sweet darling,” talk of physics turned to love, and soon they were engaged.

But in the spring of 1935, amid the dilemma of whether to move to America, Chandra told his father that he “realized that my relation with Lalitha was purely illusionary and that I really had not known her at all.” He had broken off the engagement.

A year later, before moving to Yerkes, Chandra visited India. He met with Lalitha to talk things over, and his decision to indefinitely postpone marriage “wilted away rather suddenly,” writes Wali. “She was more than a dream, she was quite real.”

They wed within a month—entering into a “love marriage,” unusual in their time—and soon moved to Williams Bay, Wisconsin, where Yerkes is located. Lalitha attended lectures at the observatory, and Chandra urged her to resume her physics research. “But I made the decision not to continue,” she told Wali, because she couldn’t devote all of her time. “Chandra had to give most of his time to his science. That is the way a scientist is made.”

Subrahmanyan and Lalitha Chandrasekhar attend the 1939 dedication celebration of McDonald Observatory in the Davis Mountains of West Texas. (Photography by Elwood M. Payne; UChicago Photographic Archive, apf1-01661, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library)

Chandra and Lalitha lived at Yerkes for 27 years. “If you were in Williams Bay,” said UChicago astrophysicist and Chandra’s graduate student Peter Vandervoort, AB’54, SB’55, SM’56, PhD’60, in a 2017 interview, “you might as well be at the South Pole. Small towns in southern Wisconsin are not exactly the natural homes of academicians.” But nearly all of UChicago’s astronomy department worked there and lived in University-owned houses on the observatory’s grounds.

When Chandra was recruited, Struve was restructuring the astronomy graduate program to include more physics. He increased the coursework at the observatory, and Chandra did the bulk of his teaching there. His lectures followed his research: stellar interiors and atmospheres, stellar dynamics, and molecular spectroscopy.

The lectures were “formal and highly mathematical,” writes Osterbrock—organized, logical, eloquent. “There was a kind of cadence, a rhythm and music, to his lectures,” said Vandervoort. At the same time, Chandra was known to have little patience: “Frivolous questions from people who did not appear to have studied the material thoroughly,” said Carl Sagan, AB’54, SB’55, SM’56, PhD’60, “were dealt with in the manner of a summary execution.”

Chandra taught astrophysics for 15 years, but in 1952, the astronomy department revised its curriculum—which he had largely designed—effectively removing him. For the second time in his career, Wali notes, Chandra felt humiliated. “Most astronomers did not have very much appreciation for theoretical work of the type that Chandra did,” said Vandervoort. He “had a sense of being largely rejected by the astronomical community.”

The disaffection between Chandra and his colleagues grew, and he reexamined his early residency at Yerkes from a new perspective. His fellow recruits had been appointed assistant professors immediately and promoted the following year with tenure. Yet Chandra had started as a research associate and been reappointed the next year as an assistant professor—with no salary increase—and remained thus for four years. The others had received funds and resources denied to him.

He had found it curious that his research associate offer came directly from Robert Maynard Hutchins. “Such an appointment,” said Chandra, “does not normally need the intervention of the president of the university.” Wali notes that in the early 1960s—long past his presidency—Hutchins gave a lecture about racial strife at UChicago that explained why. He described how the appointment of a leading theoretical astronomer had been opposed “because he was an Indian, and black.” (Hutchins often claimed the best thing he did for the University was appoint Chandra.)

The young astrophysicist had also been unaware that Henry Gale, AB 1896, PhD 1899, dean of the physical sciences, attempted to block him from lecturing on campus in 1938; once again, Hutchins intervened. Chandra and Lalitha had both faced racism in their personal lives, but he later admitted to naivete about its effects on his professional life. “I was not even aware that something impolite, something improper had been done to me,” he told Wali.

Shortly after the astronomy department “repudiated” Chandra, as Vandervoort described it, Enrico Fermi invited him to join the physics department. From that point on, Chandra taught physics almost exclusively. But he didn’t abandon astrophysics altogether; that same year he became managing editor of the Astrophysical Journal, and over the next 20 years almost single-handedly developed it into the field’s leading international publication.

During his career, Chandra advised at least 46 doctoral students and presided over 1,000 colloquia. He received 20 honorary degrees, was elected to 21 learned societies, and won several prominent awards, including the National Medal of Science and, in 1983, the Nobel Prize in Physics for the work he’d conducted 53 years before, as a young man at the very start of his journey.

When Chandra first proposed black holes, the idea was deemed absurd, UChicago astrophysicist Daniel Holz, SM’94, PhD’98, told the University podcast Big Brains. Even Albert Einstein—whose work seeded the idea of black holes—had doubts. But Chandra’s math was sound.

Over the decades, evidence of their existence emerged. In 2015 the Laser Interferometer Gravitational-Wave Observatory, of which Holz is a member, detected waves created by black holes colliding. Andrea Ghez, LAB’83, shared the 2020 Nobel Prize in Physics for discovering a supermassive black hole by studying the movement of nearby stars. And the Event Horizon Telescope has released two pictures of black holes—Chandra’s unimaginable abstraction now plain to see.

Drawing on research

rsmith — Wed, 02 Nov 2022 23:37:05 +0000

rsmith Wed, 11/02/2022 - 18:37

(All illustrations by Bozhi Tian)

Maureen Searcy

The University of Chicago Magazine

Fall/22

Chemist Bozhi Tian’s art and science recast reality.

At first glance, you may see a serene lake at sunset or delicate petals on a winter-blooming tree. But look closer at UChicago professor of chemistry Bozhi Tian’s artwork and you might notice these images don’t quite capture the world as it is. They meld scenes of nature with hints of technology, much as his research merges biological and synthetic systems.

A materials scientist who works with semiconductors for biomedical applications, Tian designs devices to stimulate or modulate parts of the anatomy, such as the heart and neurons. One project his lab has been working on for almost eight years is a solar powered pacemaker. The team is also exploring technology to influence microbes, including an edible material that could modulate the gut microbiome, potentially helping to treat gastrointestinal ailments like inflammatory bowel disease.

Tian’s research is inspired by the natural world: its shapes and textures and patterns. And that influence suffuses his artwork, often created in conjunction with his science: a riverscape with a nanowire forest, a neural cell framed as a snowcapped mountain. These are created digitally, but Tian has been painting and drawing since childhood.

Encouraged by his father, Tian started practicing calligraphy when he was three years old. He branched out to painting at six and started experimenting with design software at 15 or 16, when his father bought him his first computer. (Around that time, he was falling in love with chemistry and devoting more attention to science.) He still enjoys making analog art but finds it time-consuming.

At Shanghai’s Fudan University, where Tian earned bachelor’s and master’s degrees in chemistry, his devotion to art and to science began to coalesce. He joined a research lab that designed and synthesized porous materials—orderly and geometrically structured with nanoscale pore size. Such structures exist in nature but not at the same scale, Tian says. The 2D and 3D arrangements fascinated him. “It’s essentially an art piece,” he thought.

Both scientists and artists must be innovative and imaginative, says Tian—inspired in how they re-create their vision of the world. This multidimensional creativity is particularly evident in one of his lab’s new research directions, what he calls “synthetic reality.” The team is focusing on designing tissue-like materials, but not in the traditional tissue engineering sense (such as growing artificial organs or materials for direct medical use). “We’re thinking more broadly,” he says.

Imagine incorporating organic tissue into your surroundings—an idea that struck Tian on a recent visit to the intensive care unit of Comer Children’s Hospital to meet with a collaborator. There it occurred to him that premature babies have physical and emotional needs that would have been met by their mothers’ bodies, but they are treated inside what is basically a batting-lined box. Perhaps the team could create an environment like a womb. “We don’t really need reality, as long as it feels like reality,” he says. “That should be enough.” Likewise, some stringed instruments traditionally use gut string, made from animal intestines, which produces a warmer sound than steel. But a synthetic gut-like tissue might produce an equally beautiful tone. Reality: inspired by nature, but made in a lab.

Tian believes that combining science and design is good business—it sells innovation through communication. “It helps motivate people,” he says, “bringing us together through storytelling.” But he admits that creating art is also a sort of compromise. He finds illustration relaxing but sometimes feels guilty for neglecting his research. This way, he doesn’t have to choose.

Bioelectronics on the rise

To represent interfaces where electronics and cells seamlessly integrate, Tian created this composite image, superimposing a photograph of a flexible bioelectronic device onto a Chicago harbor. Shown across the bottom half of the image, the device is itself a composite: a rolled sheet of engineered vascular tissue embedded with wires that might one day be able to measure proteins or other chemicals in blood. Tian used vertical elements—the foreground electrode grids and the background masts—to “imply an upward progression of the field of bioelectronics.” Always sensitive to color, Tian chose warm hues “to give a feeling of harmony and positivity,” noting that a harbor is a place of security and comfort. “While the background and the foreground show very distinct objects,” says Tian, their juxtaposition presents a shared spirituality.

Transformative stain

The opalescent swirls on silicon membranes, as seen here under an optical microscope, aren’t created by dyes or pigments. The color comes from a process called stain etching, which eats through the surface of the silicon, leaving holes that scatter light, creating colored “stains.” But the process does more than cast psychedelic patterns—it creates nanoporous material that functions like a solar cell. Normally solar cells need at least two layers of different material to work, but Tian’s single-layer method creates soft, flexible, and extremely small solar cells that can be used inside the body. A tiny optical fiber carries light from outside to power them. “This is transformative because without the etching, the material is almost useless,” says Tian. But after a simple engraving process, it can turn light into electricity and help a heart keep pace.

Nano-neuro blossoms

Highlighting recent breakthroughs in neural sensing and modulation, and the potential for biomaterials to treat neurological disorders, Tian illustrated a plum blossom tree. Its branches are neuron dendrites—treelike protrusions that carry signals from other neurons—as seen under an optical microscope. Tian invoked traditional Chinese painting elements: diffuse outlines, a black and dark red color palette, and a red seal in the corner. China’s national flower, the plum blossom holds special meaning. The plant, which blooms in the winter, signifies perseverance. “That’s the key message I want to highlight for this image. This is a tough field,” says Tian, who is the only faculty member working in bioelectronic stimulation interfaces at the University of Chicago. “We need perseverance to actually push through.”

Nanowired bioelectrics

Semiconductor nanowires have played a significant role in Tian’s research since graduate school. In this landscape, every element represents a cellular or nanowire feature and “tells you how the entire nanowire bioelectronics field has evolved,” he says. The mountains are cells; the river is the extracellular matrix (a network of proteins and other molecules between cells); the bridge is an intercellular nanotube (a conduit between cells); the sun is an extracellular vesicle (a membrane-enclosed globule that aids in cellular communication). In the distance, the green trees represent early research, which focused mainly on straight wires. Downstream, branched shrubbery and zigzag logs indicate new nanowire geometries. The wire bent at about 60 degrees on the mountain face depicts a device that records information from inside a cell—part of Tian’s PhD research.

Engraved curvature

Tian’s lab creates 3D nanostructures using a classic printmaking technique: lithography. Using atomic gold as a lithographic mask, the team chemically etches silicon into complex shapes. Tian built this 3D reconstruction using a series of electron microscope pictures. The image shows only the surface of a skeleton-like silicon object, part of a material designed to adhere tightly to tissue. The colors highlight the difference in curvature: blue portions curve outward while gold dips inward. The original version used blue and red—a typical color palette for science—but Tian’s choice to replace red with gold points toward his humanistic impressions. “This etching, this engraving, seems like a very painful process for a material,” he says. It creates loss, but it’s also part of growth and reaching maturity. The etching process, to him, lets inner strength shine through.

Light excitement

Imagine a snowy mountaintop with a gondola cable straddling the peak, but on a nanoscopic scale. This scanning electron microscope image that accompanied an article published in winter 2018 shows a neuron with a silicon nanowire, which works like a solar cell, perched on top. When Tian shines a light on the wire, it converts photons into electric energy, stimulating—or exciting—the neuron. This technology can either activate or silence neurons and could help treat neurological brain conditions or restore vision to a damaged retina, for instance. Most methods for neural activation are either mechanically invasive or require genetic manipulation of target cells. Like the neurons they were studying, “we were extremely excited,” says Tian, to see the device work.

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