All summer, Mac’s science center bustled as professors and students dug into collaborative research. In the summer issue of Macalester Today, writer Mike Vangel got an inside look at seven projects around the building.
You might expect Macalester’s campus to turn pretty quiet come summertime—an interlude between semesters, campus grown lush and verdant, becoming tranquil and park-like until September, and with it, a new academic year.
Look closer, though, and you’ll see bustling hives of activity all over campus, as more than 165 students delve into mentored scholarship projects, from analyzing poetry about Ireland’s sectarian violence to exploring infrastructure’s role in economic resilience to natural disasters.
Many of those students are clustered in Olin-Rice Science Center, working on collaborative research teams led by faculty advisors. On any given day, you might find student assistants—some as young as rising sophomores—monitoring chemical reactions, peering through microscopes, and calibrating lasers. Along the way, there can be stumbling blocks and surprises: no textbooks have answers to the questions they’re investigating.
For weeks at a time, researchers in every department conduct experiments and gather data for their projects, many of which ultimately generate papers published in the most prestigious journals of the professors’ respective fields. But more importantly, they’re seeking answers to questions that may affect everything from how we power our homes to how we feed the world.
We invite you to step inside Olin-Rice.
The Promise of Perovskite
James Heyman’s basement lab does have several windows, you might not know it at first glance—all of them are covered. That’s largely for safety reasons: his team is spending part of the summer beaming high-powered lasers at miniature solar panel components, part of an effort to better understand an exotic material called lead halide perovskite and its potential energy applications.
“The absorber is the most important part of the solar cell,” Heyman says. “It’s where the light is absorbed and used to generate free electrons. At the moment, the dominant absorber material [in the industry] is silicon.” While silicon works pretty well, physics theory says there should be still more efficient materials, and some that are perhaps cheaper to produce, as well. To Heyman, perovskite looks like a prime candidate. “Both of those things still have to be demonstrated, but it’s very promising.”
With the laser setup in his lab, Heyman hopes to make some determinations about perovskite’s efficiency as a solar absorber. To that end, one of his researchers, Will Setterberg ’19, is building 10 mm2 solar cells out of the material, then arranging them for what’s called ultrafast transient conductivity testing. The idea is to split a laser beam in two, so that first, one beam hits the solar cell as visible light. Then, a few picoseconds later (that is, a few trillionths of a second), the second beam hits it as infrared energy. The technique allows the team to study important characteristics of perovskite, like the frequencies of light it absorbs in real-world use (versus in theory), and how long it remains conductive after being excited by light particles.
Although it’s still too early to tell whether perovskite will ever see widespread use, Heyman is optimistic about its potential: For one, “you can produce it by solution deposition, which means you have chemicals in liquid form, and you spread it and it dries,” he says. “So in principle, you could make solar cells with a special inkjet printer, or by a roll-to-roll process like the way you print newspaper.”
The Skeleton Key
As a dinosaur paleontologist, biology and geology professor Kristi Curry Rogers is used to working with old, rare things. Still, there are two small boxes on the shelves of her office that get her excited. Inside them are 11 glass microscope slides, each containing an ultra-thin circular section of an ancient bone, some from the very first dinosaurs in existence.
“Some of these animals only are known from a single skeleton,” Rogers says. “Literally no one else on the planet has the ability to answer [our] question, because we’re the only ones with the sample.”
Working with a group of Argentinian paleontologists, Rogers convinced them to saw small sections out of skeletons they’d excavated from the Ischigualasto Formation, a site holding fossils from roughly 230 million years ago. That timing represents a critical juncture in evolution, Rogers says, as it’s essentially the dawn of the dinosaur age: at that point, there were only a handful of dinosaur species in a highly diverse world, “and then something happens, and dinosaurs start taking off. People have been wondering for a century what is so special about dinosaurs. What do dinosaurs have that all these other organisms don’t? Why do they go on to such wild success while their reptilian compatriots decline in diversity?”
Scientists have offered various hypotheses, the latest involving growth rates—maybe there was something about the way dinosaurs grew that allowed them to survive, then thrive for more than 150 million years. Because of her specialty in bone histology (the study of patterns and structures in tissue), Rogers is wellsuited to seek out an answer.
By studying the sections under microscopes, Rogers and her students (this summer, Robert Anigbogu ’21, Kai Bosley ’21, Abrielle Dillon ’21, and Lily Neuleib-Madden ’21) can look for patterns that, to the trained eye, reveal things like the structure of the animal’s blood vessels, which serves as a proxy for how it grew throughout its life. And since the sample in her office contains both dinos and non-dinos that lived in the same ecosystem at the same time, they can compare the two and perhaps determine whether the first dinosaurs really did grow differently from other species.
“No matter what we find, the answer will be really important for dinosaur scientists,” Rogers says.
Computing for Corn
Although coding and corn farming may seem like disparate enterprises, computer science professor Getiria Onsongo ’04 is hoping his work in the former will drive serious improvements in the latter.
Over the summer, Onsongo, who just completed his first year on Mac’s tenure track, opened a research lab in collaboration with the International AgroInformatics Alliance. The goal: to develop novel data-cleaning methods and create an open-source tool to help everyone from major agricultural companies to farmers in his native Kenya.
Currently, he explains, agricultural organizations such asCIMMYT (one of the groups whose data he’s using) operate stations around the world that breed varieties of corn with distinct tolerances to factors like drought and heat. At the same time, many farmers maintain logs of information about the conditions specific to their land. “But right now, there’s no central repository where you can go” for both, he says.
The first step to solving that is to design tools to improve data collection by plant-breeders and farmers. A lot of collection is still done by hand, and can contain small discrepancies, such as inconsistently capitalizing the “k” in “Kenya.” “For a computer,” he says, “that difference actually looks like it’s two different plantbreeding stations.” Another common mistake: using latitude and longitude interchangeably. Theoretically, the tool would catch these sorts of errors before they make it into a central database.
Once that’s ready, Onsongo and his students (Ayoub Belemlih ’18, Samantha Fritsche ’20, Thy Nguyen ’21, and Jonathan Scott ’19) plan to incorporate the code into a searchable platform that can be used privately—for companies working with internal data—or publicly, where users can learn about the many varieties of corn being grown throughout the world.
“Unfortunately, there are places in Kenya where food security is still a big problem,” he says. “Hopefully [this project] will give companies and farmers access to data and tools that will help them improve their production.”
Green Energy’s Paradox
Not all the research conducted over the summer involves test tubes and microscopes. Environmental studies professor Roopali Phadke’s work is more likely to include community meetings and deep dives through federal archives as she investigates pressing scientific issues that could affect broad swaths of society—namely, the future of mining.
“My work has been predominantly on water and energy politics and policy,” Phadke says. “I began to work on mining issues more recently because it was a place where the things that I knew a lot about were converging. When we think about the future of mining, we must consider the impacts to water as well as our energy economy.”
Supported by a National Science Foundation grant, Phadke and her student researchers (this summer, Ariana Lutze-Jahiel ’19 and Elizabeth Schein ’19) have spent the last few summers investigating “responsible mining”—the claim, Phadke explains, that there’s a safe and humane way to mine for metals. They’ve worked to understand how the term is used by various companies and interest groups, and how it’s actually translated into mining projects and their effects. She is particularly interested in how we can sustainably mine the rare earth metals necessary for green energy technology like solar panels, electric vehicles, and LED lights.
This year, she turned her attention to something new: the emerging field of urban mining, whereby cities aggressively recycle previously mined metals from landfills, consumer products, and discarded infrastructure like old cable and rail lines. As the idea gathers steam in Europe and other parts of the world, she’s trying to determine what similarities those places share, and why the idea has been so slow to take off in the United States.
Ultimately, she’s motivated by broader questions about how mining and green energy intersect, and what that means for addressing global climate change. “I’m quite nervous that we are headlong into this idea that we can solve climate change once we get enough solar panels and wind turbines out there,” Phadke says. “For me, mining is one place to ask these questions—where are we going to get all of the metals to solve climate change? And is there an alternative we should be investigating?”
Unlocking the Embryo
While people have long been distressed by thoughts of life’s fleeting nature, we would do well to consider the plight of C. elegans: the microscopic worms complete their entire life cycles within just three days.
It’s that same characteristic, however, that makes them incredibly useful to biology professor and department chair Mary Montgomery. “If you want to study the genetics of something,” she says, “you want something that reproduces quickly, so you can look at multiple generations in a couple weeks. That’s a big advantage.” Two more: the worms are self-fertilizing, and their bodies are transparent, making them about as perfect a model for study as scientists could ask for.
This summer, Montgomery and her students (Samuel Brancazio ’19, Sydney Jung ’19, and Manik Reddy ’21) are investigating a particular protein in the worms’ cells called MEX-3, which is known to play a crucial role in early embryonic development. Among other things, while the embryo is still only four cells, MEX-3 helps regulate which of those cells will eventually become muscle tissue and which will form the rest of the worm’s body. Without the protein, the worm can develop too much muscle (and not enough, say, neural cells), which is lethal. “We want to understand how MEX-3 regulates its targets, but also how it itself is regulated,” she says.
To test that, Montgomery is using CRISPR/Cas-9 technology to edit worms’ genes in two ways: First, she alters their DNA to “delete” sections from a specific subset of their RNA. By moving systematically down the subset, she hopes to determine which of those sections, if any, play a role in activating or silencing the MEX-3 protein. She’ll be able to tell via the second edit, in which she inserts a piece of DNA that causes the worms to glow fluorescent green when MEX-3 protein is present.
At the heart of her work is a drive to study some fundamental aspects of developmental biology. The question that interests her now, she says, is much the same as “what I’ve been interested in for 20 years: how are genes regulated at the level of RNA? [It’s] important for the early embryo, and that’s the overarching theme.”
In other words, it’s another of those timeless puzzles: understanding the earliest mechanisms of life itself.
Test Tube Toxicity
At some point you’ve probably noticed, while perusing the nutrition label on some packaged food, that along with the expected carbs, fat, and protein, you’re ingesting trace amounts of metal.
Though it may seem counterintuitive, these heavy metals—zinc, copper, and magnesium among them—play crucial roles in our bodies, according to chemistry professor Katy Splan, whose latest research primarily focuses on copper ions.“One of the most essential roles of copper is in the process of aerobic respiration,” she explains. “In the process of taking glucose and getting energy out of that, you’re ultimately transferring electrons from one chemical to another, and copper is very important in that.” But while we require some copper, the number of copper ions in our bodies must fall within a certain range: too few, and the body may not produce sufficient energy, for example; too many, and the particles can initiate chemical reactions that release toxic free radicals throughout the body.
This summer, she’s studying how those excess copper ions might react when they encounter proteins containing zinc. Specifically, Splan and her students (including Isaiah Eckart-Frank ’20 and Ingrid Kilde ’20) are looking at something called “zinc fingers.” These proteins depend on zinc to maintain their proper shape, which is crucial to their function: binding to DNA and, in some cases, regulating genes that maintain proper copper levels in the body. Because copper and zinc share many chemical similarities, she thinks that copper ions might be able to displace zinc in those proteins—changing their shape as part of the regulation process. She further suspects that copper binding to other, similar zinc proteins could be a mechanism behind copper toxicity.
“Once you take everything out of a cell and put it in a test tube, it could be a different story,” she says. “But we’re laying the chemical framework to understand what might happen.”
The human eye is remarkably fast, says DeWitt Wallace Professor of Psychology Brooke Lea—just not as fast as his lab’s tracking equipment, which measures eye movements a thousand times per second.
By beaming infrared light on a person’s pupils and then recording the reflection, Lea’s tracker can tell with astonishing accuracy where a person is looking on an attached computer display monitor, and for precisely how long. That, in turn, allows for some clever experiments: “When you measure people’s eye movements as they’re reading, you can distinguish between different theories of how we read, or how we parse sentences, or what happens when things don’t make sense.” In general, he explains, when people encounter something unfamiliar or ambiguous, their eyes will linger, indicating confusion, or deeper processing.
That’s what he’s looking for this summer as he and his students (including Garrett Salzman ’19, Olivia Shaffer ’19, and Natalie Spanos ’18) conduct research into gender and language. One of their questions: When people encounter a traditionally gendered concept like “firefighter,” but then later read that the firefighter’s name is “Emily,” does that cause confusion? For how long? “One thing we’ve been surprised to find is that people do not update their mental models the way you might think,” Lea says.
So, even after people read that the firefighter is named Emily, upon encountering the pronoun “she” later on, they’re still likely to hesitate for a fraction of a second. “There’s still a residual trace of that outdated information back there; it doesn’t get deleted the way you’d think it would.” The researchers also plan to test whether there’s a difference in reaction between people reading in English and Spanish, a language whose articles “el” and “la” signal gender before the concept is even introduced.
“The larger picture is [understanding] how people create mental representations of the world around them, and why it is so difficult to correct people’s misconceptions once they are encoded,” he says. “This is a part of that overall enterprise.”
July 25 2018Back to top