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Robots track moving objects with unprecedented precision

Mon, 02/18/2019 - 11:59pm

A novel system developed at MIT uses RFID tags to help robots home in on moving objects with unprecedented speed and accuracy. The system could enable greater collaboration and precision by robots working on packaging and assembly, and by swarms of drones carrying out search-and-rescue missions.

In a paper being presented next week at the USENIX Symposium on Networked Systems Design and Implementation, the researchers show that robots using the system can locate tagged objects within 7.5 milliseconds, on average, and with an error of less than a centimeter.

In the system, called TurboTrack, an RFID (radio-frequency identification) tag can be applied to any object. A reader sends a wireless signal that reflects off the RFID tag and other nearby objects, and rebounds to the reader. An algorithm sifts through all the reflected signals to find the RFID tag’s response. Final computations then leverage the RFID tag’s movement — even though this usually decreases precision — to improve its localization accuracy.

The researchers say the system could replace computer vision for some robotic tasks. As with its human counterpart, computer vision is limited by what it can see, and it can fail to notice objects in cluttered environments. Radio frequency signals have no such restrictions: They can identify targets without visualization, within clutter and through walls.

To validate the system, the researchers attached one RFID tag to a cap and another to a bottle. A robotic arm located the cap and placed it onto the bottle, held by another robotic arm. In another demonstration, the researchers tracked RFID-equipped nanodrones during docking, maneuvering, and flying. In both tasks, the system was as accurate and fast as traditional computer-vision systems, while working in scenarios where computer vision fails, the researchers report.

“If you use RF signals for tasks typically done using computer vision, not only do you enable robots to do human things, but you can also enable them to do superhuman things,” says Fadel Adib, an assistant professor and principal investigator in the MIT Media Lab, and founding director of the Signal Kinetics Research Group. “And you can do it in a scalable way, because these RFID tags are only 3 cents each.”

In manufacturing, the system could enable robot arms to be more precise and versatile in, say, picking up, assembling, and packaging items along an assembly line. Another promising application is using handheld “nanodrones” for search and rescue missions. Nanodrones currently use computer vision and methods to stitch together captured images for localization purposes. These drones often get confused in chaotic areas, lose each other behind walls, and can’t uniquely identify each other. This all limits their ability to, say, spread out over an area and collaborate to search for a missing person. Using the researchers’ system, nanodrones in swarms could better locate each other, for greater control and collaboration.

“You could enable a swarm of nanodrones to form in certain ways, fly into cluttered environments, and even environments hidden from sight, with great precision,” says first author Zhihong Luo, a graduate student in the Signal Kinetics Research Group.

The other Media Lab co-authors on the paper are visiting student Qiping Zhang, postdoc Yunfei Ma, and Research Assistant Manish Singh.

Super resolution

Adib’s group has been working for years on using radio signals for tracking and identification purposes, such as detecting contamination in bottled foods, communicating with devices inside the body, and managing warehouse inventory.

Similar systems have attempted to use RFID tags for localization tasks. But these come with trade-offs in either accuracy or speed. To be accurate, it may take them several seconds to find a moving object; to increase speed, they lose accuracy.

The challenge was achieving both speed and accuracy simultaneously. To do so, the researchers drew inspiration from an imaging technique called “super-resolution imaging.” These systems stitch together images from multiple angles to achieve a finer-resolution image.

“The idea was to apply these super-resolution systems to radio signals,” Adib says. “As something moves, you get more perspectives in tracking it, so you can exploit the movement for accuracy.”

The system combines a standard RFID reader with a “helper” component that’s used to localize radio frequency signals. The helper shoots out a wideband signal comprising multiple frequencies, building on a modulation scheme used in wireless communication, called orthogonal frequency-division multiplexing.

The system captures all the signals rebounding off objects in the environment, including the RFID tag. One of those signals carries a signal that’s specific to the specific RFID tag, because RFID signals reflect and absorb an incoming signal in a certain pattern, corresponding to bits of 0s and 1s, that the system can recognize.

Because these signals travel at the speed of light, the system can compute a “time of flight” — measuring distance by calculating the time it takes a signal to travel between a transmitter and receiver — to gauge the location of the tag, as well as the other objects in the environment. But this provides only a ballpark localization figure, not subcentimter precision.

Leveraging movement

To zoom in on the tag’s location, the researchers developed what they call a “space-time super-resolution” algorithm.

The algorithm combines the location estimations for all rebounding signals, including the RFID signal, which it determined using time of flight. Using some probability calculations, it narrows down that group to a handful of potential locations for the RFID tag.

As the tag moves, its signal angle slightly alters — a change that also corresponds to a certain location. The algorithm then can use that angle change to track the tag’s distance as it moves. By constantly comparing that changing distance measurement to all other distance measurements from other signals, it can find the tag in a three-dimensional space. This all happens in a fraction of a second.

“The high-level idea is that, by combining these measurements over time and over space, you get a better reconstruction of the tag’s position,” Adib says.

“The work reports sub-centimeter accuracy, which is very impressive for RFID,” says Lili Qiu, a professor of computer science at the University of Texas at Austin whose research focuses on wireless networking and communications. “The paper proposes an interesting idea that lets a ‘helper’ transmit a wideband signal compatible with RFID protocol to achieve high tracking accuracy [and] develops a … framework for RF localization that fuses measurements across time and across multiple antennas. The system has potential to support [the researchers’] target applications, such as robotic assembly and nanodrones. … It would be very interesting to see the field test results in the future.”

The work was sponsored, in part, by the National Science Foundation.

Lobster’s underbelly is as tough as industrial rubber

Mon, 02/18/2019 - 11:59pm

Flip a lobster on its back, and you’ll see that the underside of its tail is split in segments connected by a translucent membrane that appears rather vulnerable when compared with the armor-like carapace that shields the rest of the crustacean.

But engineers at MIT and elsewhere have found that this soft membrane is surprisingly tough, with a microscopic, layered, plywood-like structure that makes it remarkably tolerant to scrapes and cuts. This deceptively tough film protects the lobster’s belly as the animal scuttles across the rocky seafloor.

The membrane is also stretchy, to a degree, which enables the lobster to whip its tail back and forth, and makes it difficult for a predator to chew through the tail or pull it apart.

This flexibility may come from the fact that the membrane is a natural hydrogel, composed of 90 percent of water. Chitin, a fibrous material found in many shells and exoskeletons, makes up most of the rest.

The team’s results show that the lobster membrane is the toughest material of all natural hydrogels, including collagen, animal skins, and natural rubber. The membrane is about as strong as industrial rubber composites, such as those used to make car tires, garden hoses, and conveyor belts.

The lobster’s tough yet stretchy membrane could serve as a design guide for more flexible body armor, particularly for highly mobile regions of the body, such as elbows and knees.

“We think this work could motivate flexible armor design,” says Ming Guo, the d’Arbeloff Career Development Assistant Professor in the Department of Mechanical Engineering at MIT. “If you could make armor out of these types of materials, you could freely move your joints, and it would make you feel more comfortable.”

The full paper detailing the team’s results appeared online Feb. 14 in the journal Acta Materialia. (The journal posted an uncorrected proof on Jan. 31.) Guo’s co-authors are Jinrong Wu and Hao Zhang of Sichuan University, Liangliang Qu and Fei Deng of Harvard University, and Zhao Qin, who is a research scientist in the MIT Department of Civil and Environmental Engineering and another senior author of the paper.

Flexible protection

Guo started looking into the properties of the lobster membrane following a dinner with a visitor to his lab.

“He had never eaten lobster before, and wanted to try it,” Guo recalls. “While the meat was very good, he realized the belly’s transparent membrane was really hard to chew. And we wondered why this was the case.”

While much research has been devoted to the lobster’s distinctive, armor-like shell, Guo found there was not much known about the crustacean’s softer tissues.

“When lobsters swim, they stretch and move their joints and flip their tails really fast to escape from predators,” Guo says. “They can’t be entirely covered in a hard shell — they need these softer connections. But nobody has looked at the membrane before, which is very surprising to us.”

So he and his colleagues set about characterizing the properties of the unusual material. They cut each membrane into thin slices, each of which they ran through various experimental tests. They placed some slices in a small oven to dry, then afterward measured their weight. From these measurements, they estimated that 90 percent of the lobster’s membrane consists of water, making it a hydrogel material.

They kept other samples in saline water to mimic a natural ocean environment. With some of these samples, they performed mechanical tests, placing each membrane in a machine that stretches the sample, while precisely measuring the force applied. They observed that the membrane was initially floppy and easily stretched, until it reached about twice its initial length, at which point the material started to stiffen and became progressively tougher and more resistant to stretching.

“This is quite unique for biomaterials,” Guo notes. “For many other tough hydrogels, the more you stretch, the softer they are. This strain-stiffening behavior could allow lobsters to flexibly move, but when something bad happens, they can stiffen and protect themselves.”

Lobster’s natural plywood

As a lobster makes its way across the seafloor, it can scrape against abrasive rocks and sand. The researchers wondered how resilient the lobster’s membrane would be to such small scrapes and cuts. They used a small scalpel to scratch the membrane samples, then stretched them in the same way as the intact membranes.

“We made scratches to mimic what might happen when they’re moving through sand, for example,” Guo explains. “We even cut through half the thickness of the membrane and found it could still be stretched equally far. If you did this with rubber composites, they would break.”

The researchers then zoomed in on the membrane’s microstructure using electron microscopy. What they observed was a structure very similar to plywood. Each membrane, measuring about a quarter of a millimeter thick, is composed of tens of thousands of layers. A single layer contains untold numbers of chitin fibers, resembling filaments of straw, all oriented at the same angle, precisely 36 degrees offset from the layer of fibers above. Similarly, plywood is typically made of three or more thin layers of wood, the grain of each layer oriented at right angles to the layers above and below.

“When you rotate the angle of fibers, layer by layer, you have good strength in all directions,” Guo says. “People have been using this structure in dry materials for defect tolerance. But this is the first time it’s been seen in a natural hydrogel.”

Led by Qin, the team also carried out simulations  to see how a lobster membrane would react to a simple cut if its chitin fibers were aligned like plywood, versus in completely random orientations. To do this, they first simulated a single chitin fiber and assigned it certain mechanical properties, such as strength and stiffness. They then reproduced millions of these fibers and assembled them into a membrane structure composed of either completely random fibers or layers of precisely oriented fibers, similar to the actual lobster membrane.

“It is amazing to have a platform that allows us to directly test and show how identical chitin fibers yield very different mechanical properties once they are built into various architectures” Qin says.

Finally, the researchers created a small notch through both the random and layered membranes, and programmed forces to stretch each membrane. The simulation visualized the stress throughout each membrane.

“In the random membrane, the stress was all equal, and when you stretched it, it quickly fractured,” Guo says. “And we found the layered structure stretched more without breaking.”

“One mystery is how the chitin fibers can be guided to assemble into such a unique layered architecture to form the lobster membrane,” Qin says. “We are working toward understanding this mechanism, and believe that such knowledge can be useful to develop innovative ways of managing the microstructure for material synthesis.”

In addition to flexible body armor, Guo says materials designed to mimic lobster membranes could be useful in soft robotics, as well as tissue engineering. If anything, the results shed new light on the survival of one of nature’s most resilient creatures.

“We think this membrane structure could be a very important reason for why lobsters have been living for more than 100 million years on Earth,” Guo says. “Somehow, this fracture tolerance has really helped them in their evolution.”

This research was supported, in part, by the National Natural Science Foundation of China and State Key Laboratory of Polymer Materials Engineering.

Climate change makes summer weather stormier yet more stagnant

Mon, 02/18/2019 - 3:00pm

Climate change is shifting the energy in the atmosphere that fuels summertime weather, which may lead to stronger thunderstorms and more stagnant conditions for midlatitude regions of the Northern Hemisphere, including North America, Europe, and Asia, a new MIT study finds.

Scientists report that rising global temperatures, particularly in the Arctic, are redistributing the energy in the atmosphere: More energy is available to fuel thunderstorms and other local, convective processes, while less energy is going toward summertime extratropical cyclones — larger, milder weather systems that circulate across thousands of kilometers. These systems are normally associated with winds and fronts that generate rain.

“Extratropical cyclones ventilate air and air pollution, so with weaker extratropical cyclones in the summer, you’re looking at the potential for more poor air-quality days in urban areas,” says study author Charles Gertler, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “Moving beyond air quality in cities, you have the potential for more destructive thunderstorms and more stagnant days with perhaps longer-lasting heat waves.”

Gertler and his co-author, Associate Professor Paul O’Gorman of EAPS, are publishing their results this week in the Proceedings of the National Academy of Sciences.

A shrinking gradient

In contrast to more violent tropical cyclones such as hurricanes, extratropical cyclones are large weather systems that occur poleward of the Earth’s tropical zone. These storm systems generate rapid changes in temperature and humidity along fronts that sweep across large swaths of the United States. In the winter, extratropical cyclones can whip up into Nor’easters; in the summer, they can bring everything from general cloudiness and light showers to heavy gusts and thunderstorms.

Extratropical cyclones feed off the atmosphere’s horizontal temperature gradient — the difference in average temperatures between northern and southern latitudes. This temperature gradient and the moisture in the atmosphere produces a certain amount of energy in the atmosphere that can fuel weather events. The greater the gradient between, say, the Arctic and the equator, the stronger an extratropical cyclone is likely to be.

In recent decades, the Arctic has warmed faster than the rest of the Earth, in effect shrinking the atmosphere’s horizontal temperature gradient. Gertler and O’Gorman wondered whether and how this warming trend has affected the energy available in the atmosphere for extratropical cyclones and other summertime weather phenomena.

They began by looking at a global reanalysis of recorded climate observations, known as the ERA-Interim Reanalysis, a project that has been collecting available satellite and weather balloon measurements of temperature and humidity around the world since the 1970s. From these measurements, the project produces a fine-grained global grid of estimated temperature and humidity, at various altitudes in the atmosphere.

From this grid of estimates, the team focused on the Northern Hemisphere, and regions between 20 and 80 degrees latitude. They took the average summertime temperature and humidity in these regions, between June, July, and August for each year from 1979 to 2017. They then fed each yearly summertime average of temperature and humidity into an algorithm, developed at MIT, that estimates the amount of energy that would be available in the atmosphere, given the corresponding temperature and humidity conditions.  

“We can see how this energy goes up and down over the years, and we can also separate how much energy is available for convection, which would manifest itself as thunderstorms for example, versus larger-scale circulations like extratropical cyclones,” O’Gorman says.

Seeing changes now

Since 1979, they found the energy available for large-scale extratropical cyclones has decreased by 6 percent, whereas the energy that could fuel smaller, more local thunderstorms has gone up by 13 percent.

Their results mirror some recent evidence in the Northern Hemisphere, suggesting that summer winds associated with extratropical cyclones have decreased with global warming. Observations from Europe and Asia have also shown a strengthening of convective rainfall, such as from thunderstorms.

“Researchers are finding these trends in winds and rainfall that are probably related to climate change,” Gertler says. “But this is the first time anyone has robustly connected the average  change in the atmosphere, to these subdaily timescale events. So we’re presenting a unified framework that connects climate change to this changing weather that we’re seeing.”

The researchers’ results estimate the average impact of global warming on summertime energy of the atmosphere over the Northern Hemisphere. Going forward, they hope to be able to resolve this further, to see how climate change may affect weather in more specific regions of the world.

“We’d like to work out what’s happening to the available energy in the atmosphere, and put the trends on a map to see if it’s, say, going up in North America, versus Asia and oceanic regions,” O’Gorman says. “That’s something that needs to be studied more.”

This research was supported by the National Science Foundation.

Training technicians in developing technologies

Fri, 02/15/2019 - 3:00pm

Headquartered at MIT, AIM Photonics Academy is embarking on an ambitious plan to develop a technician-training program in emerging technologies, attempting to answer the question of whether an institute known for educating world-leading scientists and engineers can play a role in helping train an outstanding technician workforce.

AIM Academy is part of the American Institute for Manufacturing Integrated Photonics (AIM Photonics), focused on integrated photonics. The Office of Naval Research recently awarded a $1.8 million Manufacturing Engineering Education Program grant for AIM Academy to create a technician-certification program in collaboration with Advanced Robotics for Manufacturing (ARM). AIM Photonics and ARM are two of 14 public-private manufacturing innovation institutes created as part of a federal program to revitalize American manufacturing, collectively known as Manufacturing USA.

Until now, AIM Academy has focused on training master’s and PhD engineers, which is what companies said they needed, through summer and winter boot camps and online courses. Integrated photonics — putting light-based technology on computer chips — has diverse applications including LIDAR for driverless cars, sensors, data centers, and the internet of things. As the technology moves from the lab to production, companies will not only need highly trained PhDs to compete, they will also need a workforce of skilled technicians to fill their manufacturing lines.

Lionel Kimerling, the Thomas Lord Professor of Materials Science and Engineering at MIT, leads the AIM Academy program for AIM Photonics. 

“Integrated photonics has enormous potential,” said Kimerling. “AIM Academy is developing programs now that will train workers for the jobs that are coming.” Since the integrated photonics industry is emerging, Kimerling said that the technician-training program would prepare students for the manufacturing positions that are open now, as well as jobs in photonics that will emerge in the years to come.

Both AIM Photonics and ARM have partnered with schools eager to roll out photonics-based certification programs. Pittsburgh-based ARM’s education and workforce development program will work with Westmoreland County Community College in Pennsylvania. As AIM Photonics’ education and workforce development program AIM Academy, will work with Stonehill College and Bridgewater State University in Massachusetts to develop a program specific to photonics technicians. Currently, both Stonehill and Bridgewater offer four-year degrees, but lack tracks for associate degrees or certification in the field.  

The territory is new for both schools. Officials say they are responsible for preparing the future workforce, and are ready to attract a new kind of student and offer their current students access to a certification program that they believe will lead directly to jobs.  

“This effort is part of a larger strategic priority to increase Bridgewater State’s ongoing expansion of educational opportunities and research in the areas of optics and photonics,” said Kristen Porter-Utley, dean of Bridgewater State University’s Bartlett College of Science and Mathematics.

Said Stonehill physics Professor Guiru “Ruby”  Gu: “We envision an innovative work-learn certificate program that brings together industry, higher education and government, and creates a hub for integrated photonics in southeastern Massachusetts.” 

Both Stonehill and Bridgewater officials say that the success of the certification programs begins with more hands-on lab work opportunities for students. The Commonwealth of Massachusetts has committed $28 million in capital equipment grants to AIM Photonics through the Massachusetts Manufacturing Innovation Initiative (M2I2) projects, and has already funded LEAPs (Labs for Education and Application Prototypes) at MIT and Worcester Polytechnic Institute, which will share the facilities with Quinsigamond Community College. Those LEAPs will be open to students who go through the technician-training program.

The 15-month certification program will end in student apprenticeships at local companies.  

“At MIT, we are interested in deploying new technologies. We also have contacts with the companies that will use these technologies,” said Kimerling. “Because of this, we can help train the future workforce.”

Predicting sequence from structure

Fri, 02/15/2019 - 11:00am

One way to probe intricate biological systems is to block their components from interacting and see what happens. This method allows researchers to better understand cellular processes and functions, augmenting everyday laboratory experiments, diagnostic assays, and therapeutic interventions. As a result, reagents that impede interactions between proteins are in high demand. But before scientists can rapidly generate their own custom molecules capable of doing so, they must first parse the complicated relationship between sequence and structure.

Small molecules can enter cells easily, but the interface where two proteins bind to one another is often too large or lacks the tiny cavities required for these molecules to target. Antibodies and nanobodies bind to longer stretches of protein, which makes them better suited to hinder protein-protein interactions, but their large size and complex structure render them difficult to deliver and unstable in the cytoplasm. By contrast, short stretches of amino acids, known as peptides, are large enough to bind long stretches of protein while still being small enough to enter cells.

The Keating lab at the MIT Department of Biology is hard at work developing ways to quickly design peptides that can disrupt protein-protein interactions involving Bcl-2 proteins, which promote cancer growth. Their most recent approach utilizes a computer program called dTERMen, developed by Keating lab alumnus, Gevorg Grigoryan PhD ’07, currently an associate professor of computer science and adjunct associate professor of biological sciences and chemistry at Dartmouth College. Researchers simply feed the program their desired structures, and it spits out amino acid sequences for peptides capable of disrupting specific protein-protein interactions.

“It’s such a simple approach to use,” says Keating, an MIT professor of biology and senior author on the study. “In theory, you could put in any structure and solve for a sequence. In our study, the program came up with new sequence combinations that aren’t like anything found in nature — it deduced a completely unique way to solve the problem. It’s exciting to be uncovering new territories of the sequence universe.”

Former postdoc Vincent Frappier and Justin Jenson PhD ’18 are co-first authors on the study, which appears in the latest issue of Structure.

Same problem, different approach

Jenson, for his part, has tackled the challenge of designing peptides that bind to Bcl-2 proteins using three distinct approaches. The dTERMen-based method, he says, is by far the most efficient and general one he’s tried yet.

Standard approaches for discovering peptide inhibitors often involve modeling entire molecules down to the physics and chemistry behind individual atoms and their forces. Other methods require time-consuming screens for the best binding candidates. In both cases, the process is arduous and the success rate is low.

dTERMen, by contrast, necessitates neither physics nor experimental screening, and leverages common units of known protein structures, like alpha helices and beta strands — called tertiary structural motifs or “TERMs” — which are compiled in collections like the Protein Data Bank. dTERMen extracts these structural elements from the data bank and uses them to calculate which amino acid sequences can adopt a structure capable of binding to and interrupting specific protein-protein interactions. It takes a single day to build the model, and mere seconds to evaluate a thousand sequences or design a new peptide.

“dTERMen allows us to find sequences that are likely to have the binding properties we're looking for, in a robust, efficient, and general manner with a high rate of success,” Jenson says. “Past approaches have taken years. But using dTERMen, we went from structures to validated designs in a matter of weeks.”

Of the 17 peptides they built using the designed sequences, 15 bound with native-like affinity, disrupting Bcl-2 protein-protein interactions that are notoriously difficult to target. In some cases, their designs were surprisingly selective and bound to a single Bcl-2 family member over the others. The designed sequences deviated from known sequences found in nature, which greatly increases the number of possible peptides.

“This method permits a certain level of flexibility,” Frappier says. “dTERMen is more robust to structural change, which allows us to explore new types of structures and diversify our portfolio of potential binding candidates.”

Probing the sequence universe

Given the therapeutic benefits of inhibiting Bcl-2 function and slowing tumor growth, the Keating lab has already begun extending their design calculations to other members of the Bcl-2 family. They intend to eventually develop new proteins that adopt structures that have never been seen before.

“We have now seen enough examples of various local protein structures that computational models of sequence-structure relationships can be inferred directly from structural data, rather than having to be rediscovered each time from atomistic interaction principles,” says Grigoryan, dTERMen’s creator. “It’s immensely exciting that such structure-based inference works and is accurate enough to enable robust protein design. It provides a fundamentally different tool to help tackle the key problems of structural biology — from protein design to structure prediction.”

Frappier hopes one day to be able to screen the entire human proteome computationally, using methods like dTERMen to generate candidate binding peptides. Jenson suggests that using dTERMen in combination with more traditional approaches to sequence redesign could amplify an already powerful tool, empowering researchers to produce these targeted peptides. Ideally, he says, one day developing peptides that bind and inhibit your favorite protein could be as easy as running a computer program, or as routine as designing a DNA primer.

According to Keating, although that time is still in the future, “our study is the first step towards demonstrating this capacity on a problem of modest scope.”

This research was funded the National Institute of General Medical Sciences, National Science Foundation, Koch Institute for Integrative Cancer Research, Natural Sciences and Engineering Research Council of Canada, and Fonds de Recherche du Québec.

MLK Luncheon: America’s bank of justice is overdrawn but not bankrupt

Fri, 02/15/2019 - 10:40am

In one of the less-remembered passages of Martin Luther King Jr.’s celebrated “I have a dream” speech in 1963, he spoke eloquently about the large debt owed by this country to its black citizens after centuries of oppression — which he described as a bad check that was being returned from the bank of justice, marked “insufficient funds.”

That passage formed the theme for this year’s 45th annual MIT Martin Luther King Jr. celebration luncheon, which featured a keynote address by Rahsaan Hall, director of the Racial Justice Program for the Massachusetts branch of the American Civil Liberties Union. “We refuse to believe the bank of justice is bankrupt,” the event’s program proclaimed.

MIT President L. Rafael Reif, referring to King’s words, said that “he spoke at a moment when the nation was rocked by painful inequality and violent suppression. Yet somehow, even in the face of so much turmoil, he was hopeful.”

Reif continued, “He made it clear that, to remain true to its ideals, America’s ‘bank of justice’ owes everyone the same essential guarantee of freedom and equality. Today, we obviously have not conquered discrimination, inequality, and violence. But I believe we can see some signs that the story is changing. And we can certainly see opportunities for each of us to help accelerate that change.”

As one clear example of that progress, he said, “Let’s take a moment to appreciate the fact that the U.S. Congress is now the most diverse in our nation’s history!” And, he said, despite the disturbing stories about political leaders in Virginia who were found to have worn blackface, “even in this discouraging story, I believe there is an important thread of hope.” In King’s time, he said, such activities would have been considered routine, but that’s no longer true. “Today — fortunately, finally! — it is a public outrage.”

In introducing Hall, Reif cited some of his achievements working with the ACLU: “Through a strategic combination of advocating on Beacon Hill, pursuing targeted lawsuits, and engaging people in their neighborhoods, Rahsaan works to advance racial justice in communities across the state,” he said.

Hall also reflected on King’s famous speech, pointing out that while his uplifting words of hope are well-remembered, and the speech “touches us in a very special way,” sometimes people gloss over the tough critique of American society that he also expressed. King referred to the lives of African-Americans as “a lonely island of poverty in the midst of a vast ocean of material prosperity,” and he went on to say that “it’s obvious today that America has defaulted on its promissory note … instead of honoring its sacred obligations, it has given its Negro citizens a bad check.”

He added that King said “he refused to believe that the bank of justice is bankrupt. He refused to believe that there are insufficient funds in the great vaults of opportunity of this nation. So we have come to cash this check, that will give us on demand the riches of freedom and security of justice.”

Hall pointed out that while King spoke of the lofty vision embodied in the U.S. Constitution, its drafters never really imagined that it would apply to all of humanity, including black people, native Americans, and women. “Even though King’s vision was one of hope and of high ideals, the reality is that this [Constitution] is a document that is rooted in a history of white supremacy. Not white supremacy as people think of skinheads and neo-Nazis and alt-right, but white supremacy as a system or structure of beliefs that center and prioritize and lift up and normalize white lives, white values, white beliefs, at the expense of the lives, values, property, behavior, and cultures of people of color.”

He described in detail some of the laws and policies after emancipation that codified a deep level of discrimination and disempowerment, including laws that criminalized not having a job or a permanent residence, and that he said amounted to a new form of state-sanctioned slavery. Discrimination continued to be formalized well into the 20th century, through “separate but equal” policies that enforced segregated housing and education. “Jim Crow did not operate alone. He had an Uncle, and his name was Sam,” Hall said.

Even though there has been much progress, Hall said, recent research has shown a mixed picture, with both advances and setbacks since the Kerner Commission report in the 1960s that found systematic discrimination throughout American society. “I say to you that the bank of justice is not actually bankrupt,” he concluded, “but rather America’s account is overdrawn. There is too much justice for a small segment of society, at the expense of too many others.”

The annual luncheon, as always, included musical selections as well as tributes to this year’s recipients of the Martin Luther King Jr. Leadership Award and to visiting professors and scholars, as well as talks by selected graduate and undergraduate students.

Dasjon Jordan, a graduate student in the Department of Urban Studies, said that the promissory note King spoke of “was not just about racial harmony and handholding. But Dr. King’s address was explicitly about racial and economic justice. It was about people of color having their rights as Americans activated and being able to access fair employment opportunities, housing, education, and to simply provide quality lives for their families.”

Jordan asked, “What are we doing as a body to not only make sure that classrooms aren’t just diverse and inclusive by the number of skin tones we count, but by the content of our curriculum and our actions to prioritize equity and racial justice? We must remember that diversity and inclusion are not substitutes for justice and equity. Justice and equity should not be a suggestion here, but our collective mission.

“The world is watching not only what we produce, but the values we championand processes we take to get there,” he said. “These values and processes become the checks we deposit to America’s bank as we work. … Our engagement should bring problems of racial, economic, and social injustice to the heart of our institution and our daily actions. We must all ask ourselves the hard questions and hold ourselves accountable to solving them with fierce urgency.”

Nikayah Etienne, a senior in mechanical engineering, described growing up in a predominantly black, immigrant community and school, and finding that she first really experienced being a racial minority when she began her studies at MIT. She realized that while this made her highly visible, it also made her often overlooked. But she soon found groups of black students and faculty in which she felt included and respected.

“I’m leaving here with significant lessons and experiences,” she said. “I leave here knowing that I have grown as an activist. I leave here knowing that I want to continue to touch the lives of young boys and girls who have come from similar backgrounds to me, reminding them that systematic racism and stereotyping do not define their potential.”

She added, “I challenge everyone sitting here, and all the members of the MIT community, to start making it a vision and a priority of yours, to aid students of color in cashing their own checks. I challenge you to take the necessary action to move MIT toward a more equitable community. Let our voices be heard.”

From summer research program to PhD dissertation

Fri, 02/15/2019 - 12:00am

One of the most important aspects of MIT’s educational mission is preparing students to be effective members of their scientific and technological communities. For Raspberry Simpson, that process began when she was a 17-year-old participant in the MIT Summer Research Program (MSRP); it is reaching fruition today as she pursues her doctorate in nuclear science and develops novel diagnostics for inertial confinement fusion and high-energy-density physics experiments at some of the country’s most advanced research facilities.

In 2010, Simpson (then a student in Bard College’s Early College program) worked with MIT physics professors Lindley Winslow and Janet Conrad at the Laboratory for Nuclear Science. In addition to their academic work in the MSRP, she recalls, “they put it into my mind subconsciously that MIT was a place for me, that I could do science and be accepted in this space. I can’t emphasize enough how important that is.”

Shortly afterward, Simpson transferred to Columbia University to complete her bachelor’s degree in applied physics. During that time she took a year off from study to assist Winslow with development of a neutrino detector, and work on astrophysics experiments at Los Alamos National Laboratory, where she received important mentoring. 

“I really enjoyed the national laboratory environment; it’s really special to have that many scientists in one place working towards a similar goal,” says Simpson.

In large part because of her experience in MSRP, which seeks to motivate members of under-represented groups to pursue graduate education, Simpson applied to the MIT Department of Nuclear Science and Engineering (NSE) for her PhD studies. “I felt I had a science family here,” she says. “Also, Mareena Robinson, who did the MSRP at the same time I did, was in the PhD program. Having representation from women, especially black women, in the department was a huge factor in me wanting to come back.”

Today, a primary focus of Simpson’s is working on developing diagnostics that allow the assessment of the performance inertial confinement fusion (ICF). There has been a recent surge in optimism about fusion becoming a practical, plentiful, carbon-free energy source, with increased private funding and several private companies (including MIT spinout Commonwealth Fusion Systems) announcing roadmaps for demonstration fusion power plants by the mid-2020s.

To achieve that, ICF compresses pellets of hydrogen isotopes deuterium and tritium to such extremely high temperatures and densities that the isotope nuclei fuse. This creates a heavier nucleus while releasing large quantities of heat in the form of neutrons. Work to date has been promising, but researchers have struggled to extract the full measure of energy from the process.

“The problem we’ve noticed is that there are lots of asymmetries in the implosion; if you think about trying to compress a basketball to the size of a pea, it would be difficult to keep it perfectly spherical,” explains Simpson. “That leads to inefficiencies.”

Simpson is working to develop new ways of measuring and characterizing these asymmetries during the implosion, using a pair of orthogonally positioned charged-particle instruments to measure the spectra of deuterons (deuterium nuclei) scattered during the process. The approach allows inference of variations in density and symmetry.

“Fusion is very complex, and you need as many diagnostics and as much information as you can get to understand the dynamics of these experiments,” notes Simpson, whose role at MIT’s Plasma Science and Fusion Center also connects her to the center’s research into magnetic-confinement fusion, the other leading potential path to energy production.

The project is supported by grants from the U.S. Department of Energy (DoE) and the University of Rochester’s Laboratory for Laser Energetics (LLE); Simpson has worked on several projects at the LLE’s Omega laser facility, a key research resource for fusion and other high-temperature high-density phenomena.

In addition, Simpson was chosen this year for the inaugural class of the DoE’s National Nuclear Security Laboratory Residency Graduate Fellowships, which support long-term security-related study and research at national labs. She will build a charged-particle spectrometer for a group under Tammy Ma at the National Ignition Facility at Lawrence Livermore National Laboratory, which is using a high-intensity petawatt-class laser to generate highly accelerated ions for use in radiography of a variety of targets.

Simpson recently passed her NSE qualifying examinations, and will be turning her attention to her dissertation, writing about the two pieces of work mentioned above, and an additional project that utilizes knock-on deuterons for imaging of ICF asymmetries.

“Our group in the High Energy Density Physics Division has lots of fingers in lots of pies, like fusion, high energy density science, and astrophysics, so my dissertation will include multiple projects,” says Simpson. The group recently received a prestigious Center of Excellence award from the National Nuclear Security Administration

Looking ahead, Simpson says she would enjoy working at a national laboratory, because of both the research culture and labs’ role in cultivating new generations of scientists. “The national labs have a deep understanding of the value of students, and they wouldn’t exist without continued stewardship of student talent, and I’d like to position myself in that environment. I’m not mentoring yet, but eventually I would like to give back in that way.”

She’s also a big fan of the 32-year-old MSRP, and of Institute efforts to make the science and engineering communities more inclusive. 

Dance brings a community together

Thu, 02/14/2019 - 12:55pm

For the first time during MIT’s Independent Activities Period (IAP), the MIT Bhangra Dance Team held a series of dance workshops for the MIT community.

More than two dozen students packed into McCormick Hall’s dance studio to learn step-by-step choreography prepared by two Bhangra dance team members, MIT juniors Rishi Sundaresan and Tarun Kamath.

“We decided to have these workshops during IAP because we figured people at MIT would have more free time,” says Divya Goel, senior and co-captain of MIT Bhangra. “I think we had one of the biggest turnouts ever because of this, which is awesome.”

Bhangra, which originates from the state of Punjab in northern India, is a high-energy, upbeat folk dance that was traditionally performed at harvest festivals or celebrations. With its global growth in popularity in recent years, bhangra has now become a competitive dance form throughout the world.

MIT Bhangra started in 1991 with a mission to spread and share bhangra traditions and culture. Kamath says he joined the dance group because he wanted a community where he could have fun and de-stress, but it turned into something bigger.

“Being part of a dance team starts out as loving the dance form, but what it becomes is a community and a family that you can appreciate for many years,” he says.

In addition to their performances on campus and dance competitions, each summer the group hosts Summer Bhangra, a twice-weekly summer dance workshop for people of all ages and skill levels in the Greater Boston area.

“Knowing that we’re able to teach people so quickly and seeing everyone happy from learning this dance style is really rewarding,” says Goel.

Kamath says that at the end of the day, it’s about more than learning the dance moves.

“If you can walk out of the dance workshop and had a fun two hours, then that’s the best thing that can be said.”

J-WAFS grants advance sustainable agriculture

Thu, 02/14/2019 - 12:40pm

MIT is known for its thriving innovation ecosystem: Numerous programs and funding mechanisms have evolved to ensure that new technologies and business models developed on campus can move beyond it to benefit the world.

Among them is the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), which brings its mission-driven concern for the safety, supply, efficiency, and accessibility of the planet’s water and food systems to MIT’s innovation ecosystem through the J-WAFS Solutions grant program. The program provides one-year, renewable, commercialization grants aimed to support MIT principal investigators in scaling up early stage technologies that are poised to have a measurable, international impact, and bring tangible economic and societal benefits to the communities where they are deployed. It provides the essential support that entrepreneurially-minded members of the Institute’s research community need to leverage bench-scale innovations into start-up-ready technologies.

The program is supported by Community Jameel and administered in partnership with the MIT Deshpande Center for Technological Innovation. This month, J-WAFS is distributing the call for submissions for fall 2019 funding. At the same time, J-WAFS has announced recent J-WAFS Solutions grants for two technologies aimed at increasing the resiliency of farmers and the ecosystems within which they operate.  

Precision agriculture for smallholder farmers

The challenge of yield gaps — the difference between farmers’ yields and what is attainable for a given region — is well documented, especially in the Global South, where the majority of the agricultural landscape is occupied by smallholder farmers. 

Many factors contribute to these yield gaps, though one of the primary causes is soil nutrient deficiency. With global population on the rise and consumption patterns changing, closing yield gaps is a critical avenue for sustainably feeding these growing numbers of people. The use of fertilizers can help solve the challenges posed by soil nutrient deficiency, but fertilizer can be prohibitively expensive for some smallholder farmers and also can, if misapplied, have a negative environmental impact. 

The use of sensors that accurately detect soil nutrient needs can help. Analyses show that appropriate application of fertilizer will increase the crop productivity. When sensors provide accurate information to farmers right at the farm, they can more efficiently use expensive fertilizer and avoid inefficient under or overuse.  Reducing overuse then saves money and reduces the environmental impact of runoff.

An interdisciplinary team of MIT researchers has received a J-WAFS Solutions grant to commercialize an affordable sensor that they have developed, one that is aimed at accessibility and ease-of-use. They call it QuantiSoil; it is a sensor that can indicate soil nutrient levels and deficiencies related to the type of crops grown, providing information in an easily digestible manner.  This on-site soil analysis system uses printed ion-selective electrodes, combined with an electrochemical reader, to obtain actionable soil health information.

The “QuantiSoil: Commercialization of an On-Site Analysis System for Smallholding Farmers” project team consists of A. John Hart, an associate professor of mechanical engineering, and Chintan Vaishnav, senior lecturer at the Sloan School of Management and academic director of the MIT Tata Center for Technology and Design, as well as Michael Arnold, a PhD candidate in the Department of Mechanical Engineering. J-WAFS Solutions funding is supporting the scale-up of this sensor technology and field trials that will be conducted in 2019.

Sticky sprays to reduce runoff

Kripa Varanasi, associate professor of mechanical engineering, received a 2017 grant to support the development of a new mechanism that, when used for the application of agricultural pesticides, helps the droplets adhere more effectively to leaf and fruit surfaces. 

The project, “Reducing Runoff and Environmental Impact of Agricultural Sprays,” has now received a renewal grant that will support further field testing and refinement of the technology for use on farms. When farmers spray their fields with pesticides or other crop treatments, only a very small percentage of the spray sticks to the plants. This means that a high proportion of the material rolls off of plants, lands on the ground, and becomes part of the runoff that contributes to the pollution of soils, surface water, and groundwater. 

The novel technology developed by Varanasi and his team addresses this problem through the use of two different polymers that affect the electric charge of a spray. When two oppositely-charged drops meet on a leaf surface, they more effectively stick to the plant. Early field trials have shown that this technology can significantly reduce the amount of pesticides needed for specific crops. Once commercialized, the spray technology could reduce the environmental impact of agriculture sprays and also prove more cost effective for farmers. 

Though the J-WAFS Solutions program is a critical support for entrepreneurially-minded MIT faculty and students, the mission is about more than innovation. The technologies developed through this program, like QuantiSoil and the agriculture spray under development by Varanasi and his team, are more urgently needed than ever as humankind adapts to a rapidly expanding and evolving population on a changing planet and advancements in our water and food systems technologies become critical tools for resiliency.

Podcast reveals the tough reality of building a business

Thu, 02/14/2019 - 12:30pm

Angie Hicks of Angie’s List went from doorsteps to NASDAQ. Facebook founder Mark Zuckerberg turned his dorm room idea into a Silicon Valley corner office. A co-founder “blind date” between Julie Rice and Elizabeth Cutler sparked the cult-like following of Soul Cycle.

Sure, there were challenges (and legal battles) along the way, but happy endings came for these entrepreneurs — which make for easy fairytales to tell in glossy profiles and curated news sites.

Frederic Kerrest, MBA ’09, wants to change that with his newly launched podcast “Zero to IPO.”

“It’s a lonely thing to try to build a company,” said Kerrest, who is the co-founder and COO of identity management company Okta. “It’s super-hard. People go through these bumps in the road, but all they read in the media is people who are doing amazingly. You’re like ‘Aw man, I’m the only one this is happening to,’ and the reality of it is it’s happening to everyone. Even really successful people. It’s kind of letting people know you’re not all alone out there.”

“Zero to IPO” has launched three episodes, with plans to release a new episode weekly. There are 12 episodes total, each one dedicated to a step in the journey toward an initial public offering. These steps include many firsts — idea, team, big win, screw-up — as well as what happens after the IPO.

Kerrest has the street cred to back up the podcast. He started Okta in 2009, during the second semester of his graduating year at the MIT Sloan School of Management. The company went public in 2017 and is valued at more than $7 billion.

In the past 10 years, Kerrest has received many phone calls from entrepreneurs with questions about starting and growing their own businesses. What he’s noticed, he said, is the trend toward questions on what he called “tribal knowledge.”

“There’s no website that’s got all the answers to how do I structure my first round of financing, how do I hire my first salesperson, or after my first five customers how do I get my next 50,” Kerrest said. “How do I pay the first people, what should my equity pools look like; really getting into the concrete details. It’s almost like you have to have gone through it.”

The same went for media coverage, he explained. What was missing from articles, news segments, and business podcasts were the challenges and questions entrepreneurs would call Kerrest about. 

“Very rarely was there anything about the bumps in the road, or the trials and travails,” he said.

Kerrest reached out to a college friend, Josh Davis (a contributing editor at WIRED), and the two decided to tap into Kerrest’s network of successful entrepreneurs to see who would be willing to share their own stories and advice.

Guests on the show include Julia Hartz of Eventbrite, Parker Harris of Salesforce.com, and Patty McCord of Netflix.

Each step will include stories from entrepreneurs, and some of their stories might be conflicting, Kerrest said. One entrepreneur might have decided not to pursue a lot of venture capital money in favor of managed growth, while another might have wanted to go all in. Their views are opposing, but they were both successful in their own ways.

“So entrepreneurs can walk away [feeling like] it was entertaining but also educational,” Kerrest said. “Like I learned some things, specific tips from people who have done it before, who are well-known, who are almost being vulnerable. They’re telling you what happened to them that you’re never going to hear about otherwise.”

Giving keener “electric eyesight” to autonomous vehicles

Thu, 02/14/2019 - 12:00am

Autonomous vehicles relying on light-based image sensors often struggle to see through blinding conditions, such as fog. But MIT researchers have developed a sub-terahertz-radiation receiving system that could help steer driverless cars when traditional methods fail.

Sub-terahertz wavelengths, which are between microwave and infrared radiation on the electromagnetic spectrum, can be detected through fog and dust clouds with ease, whereas the infrared-based LiDAR imaging systems used in autonomous vehicles struggle. To detect objects, a sub-terahertz imaging system sends an initial signal through a transmitter; a receiver then measures the absorption and reflection of the rebounding sub-terahertz wavelengths. That sends a signal to a processor that recreates an image of the object.

But implementing sub-terahertz sensors into driverless cars is challenging. Sensitive, accurate object-recognition requires a strong output baseband signal from receiver to processor. Traditional systems, made of discrete components that produce such signals, are large and expensive. Smaller, on-chip sensor arrays exist, but they produce weak signals.

In a paper published online on Feb. 8 by the IEEE Journal of Solid-State Circuits, the researchers describe a two-dimensional, sub-terahertz receiving array on a chip that’s orders of magnitude more sensitive, meaning it can better capture and interpret sub-terahertz wavelengths in the presence of a lot of signal noise.

To achieve this, they implemented a scheme of independent signal-mixing pixels — called “heterodyne detectors” — that are usually very difficult to densely integrate into chips. The researchers drastically shrank the size of the heterodyne detectors so that many of them can fit into a chip. The trick was to create a compact, multipurpose component that can simultaneously down-mix input signals, synchronize the pixel array, and produce strong output baseband signals.

The researchers built a prototype, which has a 32-pixel array integrated on a 1.2-square-millimeter device. The pixels are approximately 4,300 times more sensitive than the pixels in today’s best on-chip sub-terahertz array sensors. With a little more development, the chip could potentially be used in driverless cars and autonomous robots.

“A big motivation for this work is having better ‘electric eyes’ for autonomous vehicles and drones,” says co-author Ruonan Han, an associate professor of electrical engineering and computer science, and director of the Terahertz Integrated Electronics Group in the MIT Microsystems Technology Laboratories (MTL). “Our low-cost, on-chip sub-terahertz sensors will play a complementary role to LiDAR for when the environment is rough.”

Joining Han on the paper are first author Zhi Hu and co-author Cheng Wang, both PhD students in in the Department of Electrical Engineering and Computer Science working in Han’s research group.

Decentralized design

The key to the design is what the researchers call “decentralization.” In this design, a single pixel — called a “heterodyne” pixel — generates the frequency beat (the frequency difference between two incoming sub-terahertz signals) and the “local oscillation,” an electrical signal that changes the frequency of an input frequency. This “down-mixing” process produces a signal in the megahertz range that can be easily interpreted by a baseband processor.

The output signal can be used to calculate the distance of objects, similar to how LiDAR calculates the time it takes a laser to hit an object and rebound. In addition, combining the output signals of an array of pixels, and steering the pixels in a certain direction, can enable high-resolution images of a scene. This allows for not only the detection but also the recognition of objects, which is critical in autonomous vehicles and robots.      

Heterodyne pixel arrays work only when the local oscillation signals from all pixels are synchronized, meaning that a signal-synchronizing technique is needed. Centralized designs include a single hub that shares local oscillation signals to all pixels.

These designs are usually used by receivers of lower frequencies, and can cause issues at sub-terahertz frequency bands, where generating a high-power signal from a single hub is notoriously difficult. As the array scales up, the power shared by each pixel decreases, reducing the output baseband signal strength, which is highly dependent on the power of local oscillation signal. As a result, a signal generated by each pixel can be very weak, leading to low sensitivity. Some on-chip sensors have started using this design, but are limited to eight pixels.

The researchers’ decentralized design tackles this scale-sensitivity trade-off. Each pixel generates its own local oscillation signal, used for receiving and down-mixing the incoming signal. In addition, an integrated coupler synchronizes its local oscillation signal with that of its neighbor. This gives each pixel more output power, since the local oscillation signal does not flow from a global hub.

A good analogy for the new decentralized design is an irrigation system, Han says. A traditional irrigation system has one pump that directs a powerful stream of water through a pipeline network that distributes water to many sprinkler sites. Each sprinkler spits out water that has a much weaker flow than the initial flow from the pump. If you want the sprinklers to pulse at the exact same rate, that would require another control system.

The researchers’ design, on the other hand, gives each site its own water pump, eliminating the need for connecting pipelines, and gives each sprinkler its own powerful water output. Each sprinkler also communicates with its neighbor to synchronize their pulse rates. “With our design, there’s essentially no boundary for scalability,” Han says. “You can have as many sites as you want, and each site still pumps out the same amount of water … and all pumps pulse together.”

The new architecture, however, potentially makes the footprint of each pixel much larger, which poses a great challenge to the large-scale, high-density integration in an array fashion. In their design, the researchers combined various functions of four traditionally separate components — antenna, downmixer, oscillator, and coupler — into a single “multitasking” component given to each pixel. This allows for a decentralized design of 32 pixels.

“We designed a multifunctional component for a [decentralized] design on a chip and combine a few discrete structures to shrink the size of each pixel,” Hu says. “Even though each pixel performs complicated operations, it keeps its compactness, so we can still have a large-scale dense array.”

Guided by frequencies

In order for the system to gauge an object’s distance, the frequency of the local oscillation signal must be stable.

To that end, the researchers incorporated into their chip a component called a phase-locked loop, that locks the sub-terahertz frequency of all 32 local oscillation signals to a stable, low-frequency reference. Because the pixels are coupled, their local oscillation signals all share identical, high-stability phase and frequency. This ensures that meaningful information can be extracted from the output baseband signals. This entire architecture minimizes signal loss and maximizes control.

“In summary, we achieve a coherent array, at the same time with very high local oscillation power for each pixel, so each pixel achieves high sensitivity,” Hu says.

Finding love in the lab

Wed, 02/13/2019 - 12:15pm

This past May, Larissa Nietner SM ’14 PhD ’17 and Scott Nill SM ’14 PhD ’18, dressed in academic regalia, crossed the stage at MIT’s doctoral hooding ceremony, and emerged on the other side with their doctoral degrees in mechanical engineering. Less than two weeks earlier, Nill and Nietner were at another life-changing ceremony: their wedding.

“Going through the experience of juggling wedding planning with defending our PhD theses together definitely made us stronger as a couple,” says Nill.

Nietner and Nill can trace nearly every major milestone in their relationship to a seminal event in their academic career at MIT. “We met at the Thirsty Ear on the MechE pub crawl during orientation,” recalls Nietner. “When he was introducing himself, I realized that we would be working together and got very over-excited — that was his first impression of me.”

As master’s students, Nietner and Nill were both assigned to work in MIT’s Laboratory for Manufacturing and Productivity with David Hardt, professor of mechanical engineering.

“Scott and Larissa are two of the most interesting people I know. They are a lot of fun to talk to,” says Hardt. “It’s fun to know they started to date while working in my lab.”

The research they conducted with Hardt focused on microcontact printing. Their goal was to make small scale fabrication faster and cheaper so it could be scaled up for industry.

In August of 2014, the two filed a patent application for a startup idea they developed, which later became Larissa’s PhD thesis. One day later, on a stroll in the gardens of the Longfellow House in Cambridge, Nietner and Nill shared their first kiss.

After graduating with their master’s degrees in mechanical engineering and passing qualifying exams, Nietner and Nill began their respective PhD projects in 2015. For his PhD, Nill developed models for optimizing composite aircraft production with Warren Hoburg, an assistant professor in MIT’s Department of Aeronautics and Astronautics. His work was based on ideas Nill and Nietner had during their master’s research.

For her PhD, Nietner worked with David Wallace, professor of mechanical engineering, on an idea she had developed with Nill: increasing STEM engagement among teenagers by developing a wearable device kit that high schoolers can create themselves.  

“Teenagers, especially teen girls, are some of the most technologically engaged people in our population,” explains Nietner. “But what they learn in school often is not at all related to how they connect with technology on a daily basis.”

While Nietner was refining the idea for her PhD thesis, Nietner and Nill launched STEMgem — a wearable smart device kit that teenagers can build and program themselves. “The idea is to empower teenagers to build technology themselves so they can learn about STEM in a meaningful way,” Nietner adds. “We have seen some incredibly innovative technology!”

In addition to testing and iterating devices for STEMgem, Nietner and Nill also laid the groundwork for their second venture as both a couple and business partners: an operations software company, recently named Advanced Analytics LLC.

“With Advanced Analytics, we are developing a completely new approach that bridges design, manufacturing, and operations,” explains Nill. “We’ve seen that advanced manufacturing can have cost overruns as high as 30 percent. Our approach helps engineers and managers by revealing the complex interdependencies among labor, inventory, and other parts of the factory.”

As their relationship blossomed, Nietner and Nill kept supporting each other’s research. “Our relationship was forged solving some the most difficult problems we have as engineers,” says Nill. They would bounce research ideas off each other. As a result they never stopped taking an active role in each other’s work, and experienced the highs and lows of graduate student life by each other’s side.

In May 2017, two days after the patent from their first project together was finally issued, Nill proposed to Nietner by Lake Michigan at Loyola University Chicago’s campus. “He asked me in German,” adds Nietner, who grew up in Germany.

As with their courtship, Nietner and Nill’s wedding was a decidedly “MIT” affair. Two weeks after Nietner defended her PhD thesis, the couple was married in a civil ceremony. Several months later, they had a church ceremony in southwest Germany — one month to the hour after Nill defended his own thesis. After a honeymoon in the Maldives, they landed back in Boston two days before their doctoral hooding ceremony.

“One of the best parts of being married to someone who has been through the MIT PhD program is you have an immense amount of understanding and empathy for what the other person is going through,” says Nill. “We never had to explain the qualifying exam process or thesis defense process to one another.”

Nietner and Nill will continue to work together professionally. In addition to collaborating on STEMgem and Advanced Analytics, as of January they both belong to the research group of Stephen Graves, the Abraham Siegel Professor of Management at the Sloan School of Management.

Turning desalination waste into a useful resource

Wed, 02/13/2019 - 10:59am

The rapidly growing desalination industry produces water for drinking and for agriculture in the world’s arid coastal regions. But it leaves behind as a waste product a lot of highly concentrated brine, which is usually disposed of by dumping it back into the sea, a process that requires costly pumping systems and that must be managed carefully to prevent damage to marine ecosystems. Now, engineers at MIT say they have found a better way.

In a new study, they show that through a fairly simple process the waste material can be converted into useful chemicals — including ones that can make the desalination process itself more efficient.

The approach can be used to produce sodium hydroxide, among other products. Otherwise known as caustic soda, sodium hydroxide can be used to pretreat seawater going into the desalination plant. This changes the acidity of the water, which helps to prevent fouling of the membranes used to filter out the salty water — a major cause of interruptions and failures in typical reverse osmosis desalination plants.

The concept is described today in the journal Nature Catalysis and in two other papers by MIT research scientist Amit Kumar, professor of mechanical engineering John. H. Lienhard V, and several others. Lienhard is the Jameel Professor of Water and Food and the director of the Abdul Latif Jameel Water and Food Systems Lab.

“The desalination industry itself uses quite a lot of it,” Kumar says of sodium hydroxide. “They’re buying it, spending money on it. So if you can make it in situ at the plant, that could be a big advantage.” The amount needed in the plants themselves is far less than the total that could be produced from the brine, so there is also potential for it to be a saleable product.

Sodium hydroxide is not the only product that can be made from the waste brine: Another important chemical used by desalination plants and many other industrial processes is hydrochloric acid, which can also easily be made on site from the waste brine using established chemical processing methods. The chemical can be used for cleaning parts of the desalination plant, but is also widely used in chemical production and as a source of hydrogen.

Currently, the world produces more than 100 billion liters (about 27 billion gallons) a day of water from desalination, which leaves a similar volume of concentrated brine. Much of that is pumped back out to sea, and current regulations require costly outfall systems to ensure adequate dilution of the salts. Converting the brine can thus be both economically and ecologically beneficial, especially as desalination continues to grow rapidly around the world. “Environmentally safe discharge of brine is manageable with current technology, but it’s much better to recover resources from the brine and reduce the amount of brine released,” Lienhard says.

The method of converting the brine into useful products uses well-known and standard chemical processes, including initial nanofiltration to remove undesirable compounds, followed by one or more electrodialysis stages to produce the desired end product. While the processes being suggested are not new, the researchers have analyzed the potential for production of useful chemicals from brine and proposed a specific combination of products and chemical processes that could be turned into commercial operations to enhance the economic viability of the desalination process, while diminishing its environmental impact.

“This very concentrated brine has to be handled carefully to protect life in the ocean, and it’s a resource waste, and it costs energy to pump it back out to sea,” so turning it into a useful commodity is a win-win, Kumar says. And sodium hydroxide is such a ubiquitous chemical that “every lab at MIT has some,” he says, so finding markets for it should not be difficult.

The researchers have discussed the concept with companies that may be interested in the next step of building a prototype plant to help work out the real-world economics of the process. “One big challenge is cost — both electricity cost and equipment cost,” at this stage, Kumar says.

The team also continues to look at the possibility of extracting other, lower-concentration materials from the brine stream, he says, including various metals and other chemicals, which could make the brine processing an even more economically viable undertaking.

“One aspect that was mentioned … and strongly resonated with me was the proposal for such technologies to support more ‘localized’ or ‘decentralized’ production of these chemicals at the point-of-use,” says Jurg Keller, a professor of water management at the University of Queensland in Australia, who was not involved in this work. “This could have some major energy and cost benefits, since the up-concentration and transport of these chemicals often adds more cost and even higher energy demand than the actual production of these at the concentrations that are typically used.”

The research team also included MIT postdoc Katherine Phillips and undergraduate Janny Cai, and Uwe Schroder at the University of Braunschweig, in Germany. The work was supported by Cadagua, a subsidiary of Ferrovial, through the MIT Energy Initiative.

Thirty-six MIT students selected as 2019 Burchard Scholars

Wed, 02/13/2019 - 10:00am

The MIT School of Humanities, Arts, and Social Sciences (SHASS) has announced the 36 extraordinary sophomores and junior students selected as the 2019 class of Burchard Scholars.

Over the course of one calendar year, from February to December, the Burchard Scholars Program hosts dinner-seminars that bring together distinguished MIT faculty and promising sophomores and juniors who have demonstrated excellence in some aspect of the humanities, arts, or social sciences.

Selection is competitive; and this year’s scholars represent the breadth of the Institute's research and teaching domains, with majors that include biology, electrical engineering, music, computer science, data science, economics, molecular biology, mathematics, comparative media studies, and aerospace engineering, among others.

“The Burchard Scholars are a thrilling group of students,” writes Margery Resnick, professor of literature and director of the Burchard Scholars program. “They are energized by ideas and consistently willing to express points of view that challenge commonly held ideas.”

Expanding intellectual horizons

Named in honor of John Ely Burchard, the first dean of SHASS, the Burchard program allows for a vigorous, challenging of ideas from across the Institute. The “Burchards,” as the scholars are known, are encouraged to confront new ideas from beyond their major fields, and to use the adaptive, critical thinking skills of the humanities to interrogate unfamiliar concepts.

Andrea Wirth, SHASS academic administrator, observes that the Burchards have a unique opportunity at MIT: “They get to practice critical thinking and engagement with peers and Faculty Fellows in the process of discovering and grappling with new ideas and topics.”

“The scholars learn to respect other’s opinions and to support their own viewpoints,” says Wirth. “They have the opportunity to practice professional courtesy in the way they engage with the people around them. It’s a safe environment to prepare for interactions which will benefit the students in all kinds of future professional or academic ventures.”

Many former Burchard Scholars have been honored with prominent awards and recognition, including Rhodes, Marshall, and Truman scholarships and fellowships.

Developing leadership skills

The first event for the new Burchard scholars will be a celebratory reception in February, near the beginning of the spring semester. Subsequently, the scholars will attend seven, monthly dinner-seminars, culminating in December as they conclude the program.

Additionally, the scholars will attend one cultural event in the fall; last year’s Burchards had the chance to attend the opening night of Schoenberg in Hollywood, a new opera from Professor Tod Machover in collaboration with the Boston Lyric Opera. In 2017, students attended MIT Senior Lecturer Kenneth Urban’s world premiere production of “A Guide for the Homesick” staged by Huntington Theater Company, and the year before, they attended the Boston Lyric Opera’s production of Carmen. All productions involved talks by Burchard Faculty Fellows or the writers themselves, which enabled the Burchards to delve more deeply into the meaning of the productions.

In their year as Burchard Scholars, MIT students broaden the scope of their MIT experience and gain experience in the art of intellectual give-and-take, allowing them to take their place as colleagues and leaders in future endeavors.

The 2019 Burchard Scholars:

Muskaan Aggarwal, junior in biology

Crystal Chang, junior in biology

Fiona Chen, sophomore in computer science, economics, and data science

Isabelle Chong, sophomore in electrical engineering and computer science

Rionna Flynn, sophomore in physics

Sebastian Franjou, junior in music

Patricia Gao, sophomore in computer science and molecular biology

Cynthia Harris, junior in biology

Elissa He, sophomore in humanities and engineering

Robert Henning, junior in electrical engineering and computer science

Lior Hirschfeld, sophomore in mathematics

Catherine Huang, sophomore in computer science, economics, and data science

Ameena Iqbal, sophomore in chemistry and biology

Natasha Joglekar, sophomore in computer science and molecular biology with a minor in women's and gender studies

Talia Khan, junior in materials science and engineering; minor in music

Madeleine Kline, junior in chemistry and biology

Tingyu Li, sophomore in management

Margaret Libby, sophomore in biology

Tara Liu, junior in comparative media studies, computer science, and engineering

Aaron Makikalli, sophomore in aerospace engineering

Leanne Morical, sophomore in mechanical engineering

Ciara Mulcahy, junior in materials science and engineering

Anjali Nambrath, sophomore in physics with a minor in French

Ethan Oak, sophomore in business analytics

Maisha Prome, sophomore in biological engineering

Chad Qian, junior in economics and mathematics with computer science

J Shelly, junior in biology

Amy Shim, sophomore in humanities and engineering

Yotaro Sueoka, junior in biological engineering and brain and cognitive sciences with a minor in computer science

Steven Truong, junior in biological engineering and writing

Rona Wang, sophomore in comparative media studies

Erica Weng, junior in computer science and engineering

Isabelle Yen, sophomore in computer science, economics and data science

Whitney Zhang, sophomore in mathematical economics

Lena Zhu, junior in brain and cognitive sciences and biology with a minor in biomedical engineering

Yiwei Zhu, sophomore in computer science and engineering

Redesigning pharmacies with the consumer in mind

Wed, 02/13/2019 - 10:00am

Getting medication to a patient requires coordination between the doctor who writes the prescription, the insurance company that provides coverage, and the pharmacy that ultimately hands over the drug. Each of those layers introduce opportunities for errors and delays — which may be one reason that around a third of all prescribed medications are never picked up.

While pharmacies have traditionally played a passive role in the medication fulfillment process, startup Alto Pharmacy has been working to transform the industry with a customer-centered approach and an engineering mindset.

The company offers a software platform that streamlines the prescription procurement process and offers digital tools to further improve the experience of everyone who plays a role. That starts with patients, who can consult with Alto’s support team seven days a week and get prescriptions delivered to their door for free through Alto’s mobile app, and it extends to doctors, through the company’s AltoMD solution that automates time-consuming prescription management tasks.

Alto CTO Jamie Karraker ’12 SM ’13 co-founded the company with current CEO Mattieu Gamache-Asselin after the two engineers met while working at Facebook in San Franciso. Alto’s platform is a result of their belief that pharmacies are consumer products just like Facebook, Google, or Uber but haven’t been treated as such by incumbent pharmacy chains.

Finding a passion

Karraker came to MIT in 2008 planning to major in math, but he discovered an interest in computer science working on an experimental project in the Media Lab that involved writing code for a large, interactive screen that allowed users to drag and “throw” items across the table-like surface to others. Karraker had never built something with code before, but he found himself drawn to the cooperative atmosphere of the project. It would not be his only collaborative experience at MIT.

Karraker likes to say he had three majors at MIT: Computer science, physics, and basketball. (He served as captain of the varsity team.)

“A startup, especially in the early days, really is a team,” Karraker says. “You work super closely with a small group of people all the time, and there’s a strong sense of camaraderie because of that. That’s a big reason why I was drawn to startups, because I was missing that [after basketball]. And the skills I learned working within a team and leading a team have been handy for me as I have built out and led a team at Alto.”

If you include the master’s degree in artificial intelligence Karraker earned in his fifth year at MIT, that makes four majors by his count. Handling that course load gave Karraker a work ethic he says has proved invaluable at Alto.

“In the early days of a company there are a bunch of different ‘fire hoses’ you’re drinking from, and you have to wear a ton of hats. MIT forces you to learn how to handle that,” Karraker says. “That’s exactly what a startup is like. You have to be really deliberate about only working on the most important things.”

Designing for impact

Karraker and Gamache-Asselin began thinking about starting a company in early 2015. The founders knew they wanted to work directly with consumers, but they weren’t sure where to build a solution.

“We were feeling a bit jaded with the Silicon Valley ecosystem,” Karraker recalls. “A lot of the companies weren’t working on the most meaningful problems. We wanted to work on something that made a tangible impact on average people’s lives and, ideally, helped an underserved population using tech. We were really drawn to health care in general, but we had no health care experience at all.”

They did some research and settled on the pharmacy industry as their target because it was the closest thing they could find to a consumer product in health care. Then, after raising a seed round, the founders made a bold move to accelerate their learning curve in the industry: They bought a small pharmacy in San Francisco.

“We dove in head first and learned by fire how pharmacies work, by owning and operating our own pharmacy,” says Karraker. “We learned a ton in that first couple of months, working out of the closet of this pharmacy, and just sort of discovering all of the deep-rooted issues within pharmacies and their operational workflows.”

The founders prioritized efforts to improve coordination between different stakeholders; their current software platform, featuring AltoMD, is a key differentiator from other medication delivery companies like PillPack.

“[As we’ve built solutions], we’ve really gone deep into pharmacy, and we’ve been able to sort of peel off more layers of the onion of the industry, find more problems, and fix them with better software and better processes that in turn lead to a better patient experience,” Karraker says.

As the company has built out its software capabilities, it has also crafted an efficient operating strategy. While traditional pharmacies rely on many store locations within a single area, each with its own small staff, Alto operates out of one fulfillment center in each of its San Francisco, southern California, and Denver locations.

“In the delivery radius [of our location] in the Bay area, there are actually 400 brick and mortar Walgreens stores, so we’re saving a huge amount of money on retail space, real estate costs, and managing inventory, all by centralizing and building software to do everything more efficiently, allowing us to do the extra things we do, like free delivery.”

Alto also works to get patients the least expensive medications by automatically looking for coupons or working with doctors to find alternative medications if the ones prescribed aren’t covered by insurance. Those seemingly simple tactics are rare in the pharmacy industry, but they’ve saved Alto customers more than $10 million in medication costs to date.

All those services increase medication adherence rates and have led customers to rate Alto four times higher than big pharmacy chains, according to the company.

Alto is fresh off a $50 million funding round it closed in December, and the company is up to over 200 full-time employees (with almost as many delivery drivers), but Karraker says his team will continue working closely in the cities they currently operate in before expanding to other cities toward the end of 2019. The plan is designed to ensure Alto maintains its positive impact on patients as it scales.

“We realized early on that pharmacy is a really broken experience for the patient,” Karraker says. “At the same time, none of the incumbent pharmacies really have the mindset to think of themselves as a product. We wanted to apply a product-focused mindset and start with the user experience, and we’ll just continue to prioritize the user experience going forward.”

3Q: Machine learning and climate modeling

Wed, 02/13/2019 - 9:15am

Today, predicting what the future has in store for Earth’s climate means dealing in uncertainties. For example, the core climate projections from the Intergovernmental Panel on Climate Change (IPCC) has put the global temperature bump from a doubling of atmospheric CO2 levels — referred to as “climate sensitivity” — anywhere between 1.5 degrees C and 4.5  C. That gap, which has not budged since the first IPCC report in 1990, has profound implications for the type of environmental events humanity may want to prepare for.

Part of the uncertainty arises because of unforced variability — changes that would occur even in the absence of increases in CO2 — but part of it arises because of the need for models to simulate complex processes like clouds and convection. Recently, climate scientists have tried to narrow the ranges of the uncertainty in climate models by using a recent revolution in computer science. Machine learning, which is already being deployed for a host of diverse applications (drug discoveryair traffic control, and voice recognition software, for example), is now expanding into climate research, with the goal of reducing the uncertainty in climate models, specifically as it relates to climate sensitivity and predicting regional trends, two of the greatest culprits of uncertainty.

Paul O’Gorman, an associate professor in the MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS) and member of the Program in Atmospheres, Oceans and Climate, discusses where machine learning fits into climate modeling, possible pitfalls and their remedies, and areas in which the approach is likely to be most successful.

Q: Climate sensitivity and regional changes in climate seem to be a source of frustration for researchers. What are the obstacles there, and how can machine learning help?

A: Present-day climate models are already very useful on the one hand, but they're also faced with very challenging problems, two of which you mentioned — climate sensitivity for a doubling of carbon dioxide and regional aspects of changes in the climate, for example, how rainfall changes in a certain country. For both of those issues we would like to have more accurate climate models, and they also have to be fast because they have to be run for more than a thousand years, typically, just to get to them into the current climate state before then going forward into future climates.

So it's a question of both accuracy and efficiency. Traditionally, climate models are largely based on physics and chemistry of the atmosphere and ocean, and processes at the land surface. But they can't include everything that's happening in the atmosphere down to the millimeter scale or smaller, so they have to include some empirical formulas. And those empirical formulas are called parameterizations. Parameterizations represent complex processes, like clouds and atmospheric convection — one example of which would be thunderstorms — that happen at small scales compared to the size of the Earth, so they're difficult for global climate models to represent accurately.

One idea that has come to the fore in the last couple of years is to use machine learning to more accurately represent these small-scale aspects of the atmosphere and ocean. The idea would be to run a very expensive, high-resolution model that can resolve the process you're interested in, for example, shallow clouds, and then use machine learning to learn from those simulations. That’s the first step. The second step would be to incorporate the machine-learned algorithm in a climate model to give, hopefully, a faster and more accurate climate model. And that's what several groups around the world are exploring.

Q: To what extent can the machine-learned algorithm generalize from one climate situation, or one region, to another?

A: That's a big question mark. What we've found so far is that if you train on the current climate and try to then simulate a much warmer climate, the machine learning algorithm will fail because it's relying on analogies to situations in the current climate that don’t extend to the warmer climate with higher temperatures. For example, clouds in the atmosphere tend to go higher in a warmer climate. So that's a limitation if you only train on the current climate, but of course training on warmer climates in high-resolution models is also possible.

Interestingly, we found for atmospheric convection that if you train on the current climate and then go to a colder climate, the machine learning approach does work well. So there is an asymmetry between warming or cooling and how well these algorithms can generalize, at least for the case of atmospheric convection. The reason that the machine learning algorithm can generalize in the case of a cooling climate is that it can find examples at higher latitudes in the current climate to match the tropics of the colder climate. So different climates in different regions of the world help with generalization for climate change.

The other thing that may help is events like El Niño, where the global atmosphere on average gets a bit warmer, and so that could provide an analogy from which to learn. It's not a perfect analogy with global warming, but some of the same physics may be operating at higher temperatures so that could be something that the machine learning algorithm would automatically leverage to help to generalize to warmer climates.

Q: Does that mean there are certain areas of the climate system that machine learning will work better for versus others?

A: I was suggesting that we should train our machine learning algorithms on very expensive high-resolution simulations, but that only makes sense, of course, if we have accurate high-resolution simulations for the process we are interested in. What we've been studying — atmospheric convection — is a good candidate because we can do quite accurate high-resolution simulations.

On the other hand, if one was interested in, for example, how the land surface responds to climate change and how it interacts with the atmosphere above it, it's more difficult because there's lots of complexity. We have different types of plants, different soil. It's very heterogeneous. It's not as straightforward to get the truth from which you want to learn from models in that case. And then if we say, "Well, for aspects of the climate system that don’t have accurate expensive simulations, can we instead use observations?" Perhaps. But then we come back to the problem of trying to generalize to a different climate. So, I definitely think there are different parts of the climate system that are more amenable to the machine learning approach than others.

Also, some aspects of climate model simulations are already very good. Models are already doing well in simulating the large scale fluid dynamics of the atmosphere, for example. So those parts of climate models are very unlikely to be replaced with machine learning approaches that would be less flexible than a purely physics-based approach

Mathematician finds balance and beauty in math

Wed, 02/13/2019 - 12:00am

Since he was a child growing up in Changzhou, China, Zhiwei Yun’s appetite for mathematics was nothing but linear, growing with each year as he absorbed lessons and solved increasingly difficult problems, both in the classroom and on his own time, with a zeal that can only come from finding one’s true passion.  

But when Yun was a graduate student, he felt his trajectory come up short. In his third year, he was in a panic as he faced for the first time the difference between learning established mathematics and discovering new math as a researcher.

But his advisor Bob MacPherson, a professor at the Institute for Advanced Study, kept encouraging him to find his own way, saying “only a problem found by yourself can really interest and drive you to the final solution.”

“It was a hard time,” Yun recalls. “The hardest part of pure math research was knowing whether and when to give up on a problem.”

In his fourth year, Yun finally broke through his own mental wall and found a topic for his thesis, which continues to be a rich vein of exploration for him today.

“Being stuck and having to abandon your own idea is hard to do, and you need a lot of patience — there’s a psychological difficulty in research,” says Yun, now a newly tenured member of the MIT mathematics faculty. “Looking back, it was a big fortune. Now I’m not afraid of being stuck on a problem.”

Something sparked

Before he discovered mathematics, Yun was a child who loved to draw. He particularly liked calligraphy and would spend hours after school attempting to reproduce Chinese paintings and inscriptions.

He recalls not being particularly interested in math early on, and in fact has kept some of his workbooks from that time, which show several math problems left blank here and there. But in third grade, something sparked, and the workbooks suddenly filled up, and then some.

That year, Yun’s math teacher posted challenging math problems on the blackboard after class as a sort of extra credit. For students like Yun who could solve them, the teacher would feed more difficult questions. Yun soon developed a personal rapport with the teacher, along with an expanding interest in math.

“It was a feeling of solving something that most people couldn’t solve, I think, that triggered my interest,” Yun says.

Diving in

With his natural aptitude, Yun was funneled into China’s Math Olympiad track, and his selection exams in high school were good enough to place him on the extremely competitive and prestigious Chinese national team. In 2000, he and five of the very best math students in the country flew to South Korea, where they won gold in the 41st International Mathematical Olympiad.

After high school, Yun entered Peking University, where he found a much deeper, thrilling well of knowledge.

“In the days of Math Olympiad, we were just seeing the tips of an iceberg,” Yun says. “Now we were diving into the water and seeing the whole foundations of mathematics. And it was much more interesting than what was above water.”

Early on, he was taken with Galois theory, a mathematical solution to a problem that had puzzled mathematicians for centuries. Namely, an equation of the second degree, such as ax2+bx+c=0, can be solved by introducing a square root. Similarly, third- and fourth-degree equations can be solved with higher-order roots. But when it came to fifth-degree equations, a root-derived solution seemed impossible. It wasn’t until the 19th century when 18-year-old Évariste Galois, from France, came up with a solution.

Galois’ theory is now viewed as a key connection between number theory and abstract algebra — two subjects that were traditionally considered distinct.

“His solution was not understood by his contemporaries,” says Yun, who spent the first months of his college career absorbing the theory. “I still find it amazing how a teenager could go this far.”

After graduation, Yun headed to Princeton University to pursue a PhD in pure mathematics. When he did eventually land on a thesis topic, it was in representation theory, a branch of mathematics that seeks to represent abstract algebraic structures in concrete terms such as matrices or symmetries of shapes.

Representation theory plays a crucial role in the Langlands program, a series of associated conjectures devised by mathematician Robert Langlands, that seeks to connect the seemingly disparate fields of number theory and geometry. The Langlands program is considered one of the biggest projects in modern mathematical research, and Yun continues to work in the field of representation theory, with a focus on the Langlands program.

“The beauty of the subject”

From Princeton, Yun took up a brief stay at MIT as a postdoc, with an office on the first floor of Building 2, looking out on the Charles River. He spent his time soaking up as many seminars as he could attend, and would work happily into the night, before biking back to his Somerville apartment.

“On the whole, there was not much distraction,” Yun says. “Everything was about math research.”

As his postdoctoral work was wrapping up, he accepted a faculty position at Stanford University, while his wife, Minlan Yu, whom he met at Princeton, taught computer science at the University of Southern California. That same year, their first child was born, and Yun spent the next few years on a constant commute, traveling to Los Angeles every week or two to see his family.

“I was booking I don’t know how many tickets each year, and I remember one time arriving at San Francisco airport, and realizing I had booked a ticket for the wrong direction,” Yun recalls. “That’s when I realized I didn’t have a sense of home, and that we really needed to move to the same place.”

They both soon accepted offers to teach at Yale University, and spent a year and a half there before he took up his current professorship at MIT in January 2018, and she started as a professor in computer science just up the road, at Harvard University.

Of the graduate students Yun has so far mentored, he says that “every student has their own taste, and finds problems that interest themselves, and I encourage this. That should make the transition from student to researcher more smooth.”

He has struck up fruitful collaborations with others in the math department, all of whom share a common quality: “We are all driven by curiosity, and the beauty of the subject itself,” Yun says.

Yun continues to work on similar problems related to the Langlands program, and has found life to be more balanced, with just enough time for math, and family.

“My son, who is in kindergarten, was doing some first grade math problems before going to bed recently, and he asked me, ‘If I finish the fifth of this series of math books, am I close to you?’” Yun laughs proudly. “According to my grade school workbooks, he’s already ahead of me! I’m glad to see he’s eager to learn mathematics. Either way, he should follow his heart.”

Q&A: M. Amah Edoh on the Isabelle de Courtivron Writing Prize

Tue, 02/12/2019 - 3:00pm

The Isabelle de Courtivron Writing Prize was established in 2010 in honor of Isabelle de Courtivron, professor emerita of French studies, on the occasion of her retirement. The prize is awarded annually for student writing on topics related to immigrant, diaspora, bicultural, bilingual, and/or mixed-race experiences. This year, the prize committee is chaired by assistant professor of African studies M. Amah Edoh. Edoh answered a few questions about the origins and aims of the prize, and about its namesake. Entries are now open for the 2019 Isabelle de Courtivron Writing Prize.

Q: The de Courtivron prize invites submissions about “immigrant, diaspora, bicultural, bilingual and/or mixed-race experiences.” Why is this the focus?

A: Many of our students at MIT live across multiple cultural identities, whether as a result of having parents from different national, religious, or racial backgrounds, or as a product of migration — their own or their parents’, or ancestral dislocation, as in the case of members of the African and other diasporas. I believe that it’s incredibly important for young people from such backgrounds to have spaces where they can both process and share the experiences that living between multiple worlds bring about. Particularly because, unfortunately, there’s a way in which when we are young, we can experience this multiplicity as a burden — because we don’t fit into any one culture neatly, rather than as the asset that it actually is — the ability to be fluent in multiple cultural mores (and often, languages). This demographic of students was of particular interest to Professor de Courtivron during her time at MIT, owing both to her intellectual pursuits and to her own personal experience, having lived and worked in France, the U.S., and other countries, throughout her career. The writing contest gives students a space where they can reflect on their experiences, and share them with the MIT community as a whole. For us all it’s an invaluable chance to learn about the wealth of life experiences that make up the fabric of our community.

Q: What kind of writing is accepted for prize entries?

A: Both creative and expository writing are welcome. It could be a personal essay or a short story. Also, our students are often already engaged in thinking about questions relevant to the prize in their SHASS classes — namely, who they are in the world, and what it has meant to be them in different places. And so sometimes they already have papers they’ve written for classes on these topics that speak to the theme of the prize. We welcome those as well.

Q: What would be your advice to budding writers?

A: I think the most poignant writing for a prize like this comes out of authenticity. And by that, I mean writing that is true to your voice, your heart, and your experience. Sometimes we’re able to tap into that easily, other times it takes a bit more effort. Personally, when I don’t know where to start, I like to use “critical moments” reflection as a way to start generating ideas: reflecting on a moment that stands out for its strong emotional charge — whether you felt especially happy or sad or angry or surprised or confused. Under these strong emotions lies a meaningful experience, which might just provide a starting point, or perhaps a signpost as you continue to develop the bigger piece; write from that. The technique can be useful for both fiction and non-fiction. Also, what grabs us as readers when we read stories is the specificity of what’s being conveyed. As the writer, it can be tempting to want to focus on the universal dimension of what you’re writing about, almost at the expense of the specifics of the particular experience you’re relaying. But you have to let the story itself do much (maybe most!) of that work for you. That requires a great deal of trust in your voice and in your story. It’s also where the magic happens!

Q: The writing prize is named for Professor Emerita Isabelle de Courtivron. I understand you knew her when you were an undergrad at MIT.

A: Yes, 20 years ago, when I was a first-year student here, like all other first-years, I think, I participated in a weekly first-year seminar. The seminars were small groups led by a faculty member, that would meet around a theme. The one I took part in was led by Professor de Courtivron, and its focus was on so-called “Third Culture Kids,” a term that was quite in vogue at the time. TCK are children who grew up in a culture or cultures other than their parents’. They often feel like they don’t fully belong to either of these cultures, identifying instead with other people who share the same experience of living across cultures. This the “third culture” they belong to, the mash-up, if you will, of multiple cultural experiences. All of us in the seminar had lived all over and occupied vastly different spaces in the world prior to coming to MIT, and yet our experiences resonated deeply with one another. My family is from Togo. I spent my early years there and in Zimbabwe, and later my family moved to the U.S. I went to French schools in Zimbabwe and the U.S., and then came to college here. Another member of our first-year seminar was a young white man from the southern United States who grew up in Latin America because his parents were missionaries, another was from Myanmar, and grew up in Europe, if I remember correctly. We were all from different majors, lived in different dorms, were involved in different student groups. We would have likely never met otherwise, and yet we so needed the affirmation that a space like this provided — in particular because it was led by a faculty member who understood our experiences of the world firsthand, Professor de Courtivron.

Q: Tell us more about Professor Isabelle de Courtivron.

A: Oh, I remember her being so lively and engaging. And irreverent! She created a space for us, the students, to be free and open. She had a unique ability to connect to young people, and I think she relished hearing about our experiences as much as we loved having a “grownup” listen to us and guide us as we reflected on our own experiences and those of various “TCK” writers. I remember there being a lot of laughter. Isabelle made us feel heard and seen, and these small, warm sessions with her offered an incredibly valuable counterbalance to the large first-year lectures for core curriculum courses, where you were one among a crowd of hundreds. Isabelle remained a valued mentor to me throughout my years as an undergrad, and we still stay in touch. She currently lives in Paris, and I’ve had a chance to visit her there. Her legacy continues through this writing prize, and it is a special joy and honor for me to come full-circle in this way, if you will, by chairing the committee that will award the prize this year.

Submissions are due by March 6. Interested students can find out more about how to submit by going to mitgsl.mit.edu/writingprize. The winning entry will be published online, and there is a $400 first prize.

Why too much DNA repair can injure tissue

Tue, 02/12/2019 - 2:00pm

DNA-repair enzymes help cells survive damage to their genomes, which arises as a normal byproduct of cell activity and can also be caused by environmental toxins. However, in certain situations, DNA repair can become harmful to cells, provoking an inflammatory response that produces severe tissue damage.

MIT Professor Leona Samson has now determined that inflammation is a key component of the way this damage occurs in photoreceptor cells in the retinas of mice. About 10 years ago, she and her colleagues discovered that overactive initiation of DNA-repair systems can lead to retinal damage and blindness in mice. The key enzyme in this process, known as Aag glycosylase, can also cause harm in other tissues when it becomes hyperactive.

“It’s another case where despite the fact that inflammation is there to protect you, in some circumstances it can actually be harmful, when it’s overactive,” says Samson, a professor emerita of biology and biological engineering and the senior author of the study.

Aag glycosylase helps to repair DNA damage caused by a class of drugs known as alkylating agents, which are commonly used as chemotherapy drugs and are also found in pollutants such as tobacco smoke and fuel exhaust. Retinal damage from these drugs has not been seen in human patients, but alkylating agents may produce similar damage in other human tissues, Samson says. The new study, which reveals how Aag overactivity leads to cell death, suggest possible targets for drugs that could prevent such damage.

Mariacarmela Allocca, a former MIT postdoc, is the lead author of the study, which appears in the Feb. 12 issue of Science Signaling. MIT technical assistant Joshua Corrigan, former postdoc Aprotim Mazumder, and former technical assistant Kimberly Fake are also authors of the paper.

A vicious cycle

In a 2009 study, Samson and her colleagues found that a relatively low level of exposure to an alkylating agent led to very high rates of retinal damage in mice. Alkylating agents produce specific types of DNA damage, and Aag glycosylase normally initiates repair of such damage. However, in certain types of cells that have higher levels of Aag, such as mouse photoreceptors, the enzyme’s overactivity sets off a chain of events that eventually leads to cell death.

In the new study, the researchers wanted to find exactly out how this happens. They knew that Aag was overactive in the affected cells, but they didn’t know exactly how it was leading to cell death or what type of cell death was occurring. The researchers initially suspected it was apoptosis, a type of programmed cell death in which a dying cell is gradually broken down and absorbed by other cells.

However, they soon found evidence that another type of cell death called necrosis accounts for most of the damage. When Aag begins trying to repair the DNA damage caused by the alkylating agent, it cuts out so many damaged DNA bases that it hyperactivates an enzyme called PARP, which induces necrosis. During this type of cell death, cells break apart and spill out their contents, which alerts the immune system that something is wrong.

One of the proteins secreted by the dying cells, known as HMGB1, stimulates production of chemicals that attract immune cells called macrophages, which specifically penetrate the photoreceptor layer of the retina. These macrophages produce highly reactive oxygen species — molecules that create more damage and make the environment even more inflammatory. This in turn causes more DNA damage, which is  recognized by Aag.

“That makes the situation worse, because the Aag glycosylase will act on the lesions produced from the inflammation, so you get a vicious cycle, and the DNA repair drives more and more degeneration and necrosis in the photoreceptor layer,” Samson says.

None of this happens in mice that lack Aag or PARP, and it does not occur in other cells of the eye or in most other body tissues.

“It amazes me how segmented this is. The other cells in the retina are not affected at all, and they must experience the same amount of DNA damage. So, one possibility is maybe they don’t express Aag, while the  photoreceptor cells do,” Samson says.

“These molecular studies are exciting, as they have helped define the underlying pathophysiology associated with retinal damage,” says Ben Van Houten, a professor of pharmacology and chemical biology at the University of Pittsburgh, who was not involved in the study. “DNA repair is essential for the faithful inheritance of a cell’s genetic material. However, the very action of some DNA repair enzymes can result in the production of toxic intermediates that exacerbate exposures to genotoxic agents.”

Varying effects

The researchers also found that retinal inflammation and necrosis were more severe in male mice than in female mice. They suspect that estrogen, which can interfere with PARP activity, may help to suppress the pathway that leads to inflammation and cell death.

Samson’s lab has previously found that Aag activity can also exacerbate damage to the brain during a stroke, in mice. The same study revealed that Aag activity also worsens inflammation and tissue damage in the liver and kidney following oxygen deprivation. Aag-driven cell death has also been seen in the mouse cerebellum and some pancreatic and bone marrow cells.

The effects of Aag overactivity have been little studied in humans, but there is evidence that healthy individuals have widely varying levels of the enzyme, suggesting that it could have different effects in different people.

“Presumably there are some cell types in the human body that would respond the same way as the mouse photoreceptors,” Samson says. “They may just not be the same set of cells.”

The research was funded by the National Institutes of Health.

3Q: The symbiosis of chemistry and choreography

Tue, 02/12/2019 - 11:10am

Lindsey Orgren spends her days enthusiastically working on organic synthesis and creating new molecules in the lab of Professor Ronald T. Raines. But long before she discovered a desire for a career in science, Orgren established her passion for dance, and has maintained involvement in the art form throughout her academic career.

Orgren is originally from Edmond, Oklahoma, and majored in biochemistry and molecular biology at Hendrix College in Conway, Arkansas. She came to MIT when Raines’ group transferred from the University of Wisconsin at Madison to Cambridge in the summer of 2017. When she leaves the lab, however, she happily transforms into a choreographer extraordinaire in her free time as a member of the MIT Dance Troupe and Project 31, a Boston-based contemporary dance company committed to “exploring the boundaries between contemporary and American Jazz dance.”

Orgren’s choreography will be featured in the company’s upcoming production, “Under Control.” Project 31 Director Kenzie Finn says the piece will draw inspiration “from the emotional implications of struggling to remain in control of one's self while being controlled by external forces. Daily struggles, life altering events, and personal emotions all exert varying degrees of pressure causing humans to fall in and out of control of themselves and the world around them. ‘Under Control’ sheds a light on this personal and emotional struggle through music and movement.”

Q: How long have you been a dancer/choreographer, and what drew you to the art form?

A: I started dancing at the age of seven and have studied in tap, jazz, ballet, modern, contemporary, hip-hop, and lindy-hop. During college, I was a member of the Hendrix College Dance Ensemble, where I performed in many modern and contemporary pieces and began choreographing pieces of my own. During my time at Hendrix, my video-game-inspired contemporary/hip-hop fusion piece "Loading…" was selected to be presented at the American College Dance Association South Conference in 2015. I was also given the Theater and Dance Department’s Graham-Duncan award for ensemble leadership and excellence in dance. Upon graduating in 2015, I moved to Madison, Wisconsin, where I joined Breakthrough Dance Company. I performed several hip-hop and contemporary pieces with them, and continued to explore my choreographic style with two contemporary pieces. I moved to the Boston area in 2017 to continue my graduate education at MIT, and have since joined MIT’s Dance Troupe and Project 31.

As to what drew me to dance originally, at first it was simply one of the litany of hobbies that my parents had me try as a child. I had tried gymnastics, but tumbling was too scary. I had tried soccer, but that was too much running. Dance offered a space where I could be physically challenged and work both individually and within a team in a — mostly — non-competitive environment. Dance sparked a passion in me for performance, one which I have explored through several stage-plays and musicals as well. But dance, with its combined physical challenge and performances aspects, has stayed constant throughout my life. In college, I began to connect with dance even more on an artistic level, performing in some emotional heavy-hitters, as well as developing my choreographic style and figuring out how to tell stories or convey emotions through dance. This has culminated with my most recent piece, "Isolate" [originally choreographed for MIT Dance Troupe’s Fall 2018 show], which the most personal piece I’ve choreographed to date. Through ‘Isolate’ as well as other pieces, I have begun to view choreography as a type of therapy.

Dancing, but especially choreographing, allows me to express my thoughts in a way that feels more natural to me than speaking. As everyone knows, graduate school can be frustrating and exhausting — and at times isolating. In fact, 32 percent of PhD students are at risk of having or developing a psychiatric disorder such as depression. For a while, I admit I was one of those students, and was hit hard by depression in the middle of my graduate career. While not the only factor in my road to recovery, dance has been an integral part of my mental wellbeing. Choreographing "Isolate" has allowed me to work through the frustrations of grad school and my personal life in a productive way, and dancing with Project 31 and MIT Dance Troupe has allowed me to continue pushing myself to my physical limits retain the joy of performing in my life.

Q: What about dance, choreography, and involvement in Project 31 do you find the most inspiring?

A: When I first moved to the Boston area, I explored many dance studios and ended up taking ballet classes at Harvard for my first semester here. It was a great opportunity and allowed me to hone my technique, but I found myself yearning to perform on stage again and be a part of a group of dancers working and performing together. It was a little difficult to break into the dance scene and discover dance groups that would fit the style and time commitment I was looking for. I eventually resorted to sifting through various Facebook pages and found Project 31, a group which at that point had only just formed. I messaged the director, Kenzie, asking if I could audition, and the rest is history. I am so grateful to Kenzie for taking a chance on a stranger, and for helping me grow so much as a dancer in the past year. And especially for allowing me the opportunity to set my choreography on new dancers and expose my work to a new audience.

I am always inspired by meeting other dancers and hearing their stories and how they came to dance. In Project 31, many dancers have made dance their career through teaching and performing in other companies. But others juggle having a work-dance balance the same as I do. For instance, I briefly danced with another company, Evolve Dynamicz, in the Boston area, which was co-directed by a graduate student in architecture. Another dancer in Project 31 directs her own group, Sasso and Company, while working full time as a therapist. These dancers have been an inspiration in their duel passion for dance and their careers, and motivate me to continue to keep both dance and science as integral parts of my life.

Q: What has been the most memorable or impactful moment as a dancer, and how does having an artistic, creative outlet impact your work in the lab?

A: Hmm… I’m having a hard time thinking of one specific moment. But I will say, in general, the moment leading up to the start of a show is absolutely adrenaline-filled, if that counts as impactful. While I don’t get quite as nervous as I used to, my heart still pounds before I step on stage. The good thing is I can use that adrenaline to power my movement, and pour my energy into expressing the choreography to my fullest extent. The hardest part is when the pieces I have choreographed are up. Then I can only watch from the wings and anxiously hope everything goes smoothly, listening hard for how the audience is reacting. While I am not on stage, the applause following my choreography is all the more gratifying.

Taking time to focus on a physical and artistic outlet absolutely helps my mental wellbeing, allowing me to be more productive in lab. Not only that, but I feel having an outlet in which to express myself creatively transfers over into thinking creatively to solve experimental problems or direct my project in exciting ways.

“Under Control” will be performed at the Boston University Dance Theater on Saturday, March 2 at 7:30 p.m. and on Sunday, March 3 at 2 p.m. MIT affiliates may purchase discounted tickets, using promo code MITAC.

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