In cells, self-destructive behavior suggests strategy for fighting cancer

SOMETIMES, TO SURVIVE, our cells destroy their own ribonucleic acid (RNA), the part of our genetic instruction code that helps turn genes into proteins. Cells do this as part of the first line of defense against pathogens and damage. New research suggests how this mechanism could form the basis of a strategy against cancer.

The mechanism is part of the body’s innate immune system, which kicks into gear minutes after infection. The innate immune system holds pathogens at bay for the critical few days needed to make antibodies.

One of the mysterious weapons in the innate immune system is an enzyme called RNase L that chops up strands of RNA, an intermediate step between genes and their final products, proteins. Because viruses lack the machinery to make copies of themselves to spread infection, they hijack a cell’s reproductive technology and force it to make viral RNA and proteins. To fight back, the body sends RNase L. (The “ase” is a common ending for enzymes, and the “L” is for latent, because RNase L lies in wait for infection or damage signals.)

RNase L chops up the viral RNA, but it also shears the body’s own RNA. This self-mutilation is necessary for good health. Mice that lack RNase L are obese, diabetic and have signs of inflammation.

“This cleavage of the cell’s own RNA has a protective function. It does not always kill the cell, but when it does it eliminates only damaged or infected cells, which repairs the tissue. It ultimately means animals survive better,” said Alexei Korennykh, an associate professor of molecular biology. His lab was the first to solve the crystal structure of human RNase L, a result they published in the journal Science March 14, 2014.

Korennykh’s research is funded by the National Institutes of Health, the Sidney Kimmel Foundation, the Burroughs Wellcome Fund and the Vallee Foundation.

With the 3-D structure in hand, Korennykh and his team turned to the question of how RNase L works. Korennykh wondered if RNase L chops up every RNA that comes along, or just certain ones. To find out, the researchers sequenced every piece of RNA made in a typical human cell and evaluated them to see which ones were susceptible to RNase L.

What they found surprised them. RNase L chops up RNA strands that govern the rapid division of cells, as well as how well cells stick to each other. These two activities — when cells proliferate and attach themselves in new locations — are two of the key steps in the spread of cancer. They published the findings Dec. 29, 2015, in the Proceedings of the National Academy of Sciences.

The link between RNase L and cancer made sense because RNase L mutations are common in individuals from families with a hereditary predisposition for prostate cancer, Korennykh said. The team is exploring how to turn this discovery into a strategy for inhibiting cancer’s spread using small drug-like molecules to boost RNase L’s activity against cell proliferation and attachment.

“We really stumbled on this approach very unexpectedly,” Korennykh said. “Often the best experiments are the ones where you didn’t get the results you expected.” –By Catherine Zandonella

No more mirrors: a new way of making molecules for tracking disease

Abigail Doyle

Abigail Doyle, associate professor of chemistry (Photo by C. Todd Reichart)

RADIOACTIVITY IS USUALLY ASSOCIATED with nuclear fallout or comic-book spider bites, but in very small amounts it can be a useful tool for diagnosing diseases.

Small molecules containing a radioactive isotope of fluorine, called 18F, allow doctors to track tumors using a scanning procedure known as positron emission tomography (PET). But existing methods of making 18F radiotracers tend to produce molecules that are identical in every way but one — the molecules are oppositely oriented, like a person’s right and left hand, or like mirror images. Due to their distinct 3-D structures, only one of the mirror images — known as enantiomers — is useful for tracking tumors.

Now, researchers at Princeton University led by Abigail Doyle, an associate professor of chemistry, report a route that can selectively produce just one type of enantiomer — either right-handed or left-handed — which could aid researchers in making more potent radiotracers. The work was published online in March 2014 in the Journal of the American Chemical Society.

“We know that in biology, small-molecule interactions with enzymes often depend on the 3-D properties of the molecule,” Doyle said. “Being able to prepare the enantiomers of a given tracer, in order to optimize which tracer has the best binding and imaging properties, could be really useful.”


Molecules such as the one pictured can occur as two varieties that are identical in every way but one — they are mirror images of each other. Due to their distinct 3-D structures, these mirror images, known as enantiomers, interact with the body differently. Abigail Doyle’s group report a route that can selectively produce just one type of enantiomer, a result that could help researchers make more potent radiotracers for use in disease diagnosis.

Doyle’s research team developed a cobalt fluoride catalyst that causes radioactive fluoride to react with epoxides — triangleshaped molecules that contain an oxygen atom. The researchers’ method demonstrated excellent ability to select single enantiomers for 11 substrates, five of which are known pre-clinical PET tracers.

With this new method, researchers can test single enantiomers of existing or new PET radiotracers and evaluate if these compounds offer any advantage over the enantiomeric mixtures. Ultimately, the goal is to use this chemistry to identify a completely novel PET radiotracer for imaging.

Currently, there are only four FDA-approved 18F radiotracers. One of the major limitations to discovering PET tracers is the source of 18F. Existing 18F sources are strongly basic and, during the process of making the 18F radiotracer, can cause the elimination of alcohol and amine groups and rearrange the groups into mixtures of enantiomers in a process called racemization.

Under Doyle’s less basic reaction conditions, however, even alcohols and secondary amines are tolerated and no racemization is observed. The research was supported by the National Institutes of Health, the National Science Foundation and the Pennsylvania Department of Health.

First author Thomas Graham, who earned his Ph.D. in spring 2014, and graduate student Frederick Lambert commuted to the University of Pennsylvania, where they conducted the radiolabeling experiments in the laboratory of collaborator Hank Kung, an emeritus professor of radiology.

“We demonstrated that the radioactivity is high enough that we could actually use it for imaging. That’s an exciting next step,” Doyle said.

–By Tien Nguyen

Light-splitting crystals from inexpensive ingredients

Photonic crystals

Researchers from Princeton and Columbia universities have proposed a method for growing specialized materials called photonic crystals by ensuring that tiny particles settle into a single uniform crystal structure. Previously, the particles assumed a variety of structures, which made the resulting crystals unsuitable for high-performance uses. At left, particles form the initial two layers of a crystal, labeled A and B. With the addition of the third layer, the crystal forms one of two possible shapes, shown in side views at right. The vertical blue string to the right of each crystal shows a chemical chain that the researchers add to the mix to force one structure to form versus the other.

HIGHLY PURIFIED CRYSTALS that split light with uncanny precision are key parts of high-powered lenses, specialized optics and, potentially, computers that manipulate light instead of electricity. But producing these crystals by current techniques, such as etching them with a precise beam of electrons, is often extremely difficult and expensive.

Now, researchers at Princeton and Columbia universities have proposed a method that could allow scientists to customize and grow these specialized materials, known as photonic crystals, with relative ease.

“Our results point to a previously unexplored path for making defect-free crystals using inexpensive ingredients,” said Athanassios Panagiotopoulos, the Susan Dod Brown Professor of Chemical and Biological Engineering at Princeton. “Current methods for making such systems rely on using difficult-to-synthesize particles with narrowly tailored directional interactions.”

In an article published online July 21, 2014, in the journal Nature Communications, Panagiotopoulos and colleagues propose that photonic crystals could be created from a mixture in which particles of one type are dispersed throughout another material. Called colloidal suspensions, these mixtures include things like milk or fog. Under certain conditions, these dispersed particles can combine into crystals.

Creating solids from colloidal suspensions is not a new idea. In fact, humans have been doing it since the invention of cheese and the butter churn. But there is a big difference between making a wheel of cheddar and a crystal pure enough to split light for an optical circuit.

One of the main challenges for creating these optical crystals is finding a way to create uniform shapes from a given colloidal mixture. By definition, crystals’ internal structures are arranged in a pattern. The geometry of these patterns determines how a crystal will affect light. Unfortunately for optical engineers, a typical colloidal mixture will produce crystals with different internal structures.

In their paper, the researchers demonstrate a method for using a colloidal suspension to create crystals with the uniform structures needed for high-end technologies. Essentially, the researchers show that adding precisely sized chains of molecules — called polymers — to the colloid mixture allows them to impose order on the crystal as it forms.

“The polymers control what structures are allowed to form,” said Nathan Mahynski, a graduate student in chemical and biological engineering at Princeton and the paper’s lead author. “If you understand how the polymer interacts with the colloids in the mixture, you can use that to create a desired crystal.”

The researchers created a computer model that simulated the formation of crystals based on principles of thermodynamics, which state that any system will settle into whatever structure requires the least energy. They found that when the crystals formed, tiny amounts of polymer were trapped between the colloids as they came together. These polymer-filled spaces, called interstices, play a key role in determining the energy state of a crystal. “Changing the polymer affects which crystal form is most stable,” Mahynski said.

Besides Panagiotopoulos and Mahynski, the paper’s authors include Sanat Kumar, a professor and chair of chemical engineering, and Dong Meng, a postdoctoral researcher, both at Columbia. Support for the project was provided in part by the National Science Foundation.

–By John Sullivan

New technology enables computing with the wave of a hand


Aoxiang Tang, Liechao Huang and Yingzhe Hu

A FORWARD-THINKING TEAM of electrical engineering students has designed an interactive display surface that allows users to control objects on a screen simply by gesturing in the air. The SpaceTouch surface can either replace an existing touchscreen or be embedded below a table or behind a wall, and can interface with a phone or computer.

A wide variety of uses are possible for the technology, especially in settings where touching a screen is difficult, according to the team, which consists of electrical engineering graduate students Yingzhe Hu, Liechao Huang and Aoxiang Tang.

For instance, a surgeon in an operating room could use SpaceTouch to scroll through a patient’s X-rays. A cook could browse recipes on a surface embedded in an oven or refrigerator door. And three-dimensional sensing could create new possibilities for video games and educational tools.

SpaceTouch will make smartphones, tablets and other computers easier to use in an unobtrusive way, according to Naveen Verma, an associate professor of electrical engineering and a faculty adviser on the project, along with electrical engineering professor Sigurd Wagner and James Sturm, the Stephen R. Forrest Professor in Electrical Engineering and the director of the Princeton Institute for the Science and Technology of Materials.

“We want to interact extensively with our electronics,” Verma said. “But our base technology — the microchip — is small. It’s more appropriate, and I think more compelling, to have a display or interface that is as big as we are.” SpaceTouch makes it possible to control phones or laptops on larger surfaces. Compared to the popular Xbox 360 Kinect gaming console, SpaceTouch can detect motion at shorter distances, in a variety of lighting conditions and using less power.

The 3-D motion sensing of SpaceTouch is made possible by the addition of an extra layer beneath an everyday touchscreen. The upper sensing layer is a matrix of motion-sensing electrodes. A specialized computer chip directs the electrodes to send out a voltage that oscillates, or goes up and down at a constant frequency, creating an electric field that extends to about a foot in front of the screen.

When a hand moves through the electric field, it disrupts the field in a way that changes the frequency of the voltage oscillation. To prevent the display layer from interfering with the motion-sensing electric field, the team added a transparent, conductive shielding layer below the sensing layer, and designed the computer chip to synchronize the voltage oscillations of the two layers.

To explore commercialization of the technology Hu, Huang and Tang participated in the eLab Summer Accelerator Program, which is run by Princeton’s Keller Center in the School of Engineering and Applied Science.

Discovery2014_SpaceTouchdiagram“The eLab program is our first contact with the real business world,” Huang said. “Research is quite different from developing a commercial product.” For example, Huang said, they have learned to consider the needs of different customers and to put together an effective business pitch. The team has obtained a provisional patent, and has already presented SpaceTouch to representatives from large technology companies.

–By Molly Sharlach

Entrepreneurship at Princeton: An interview with Mung Chiang

Mung ChiangPROFESSOR MUNG CHIANG has integrated fundamental research on computer network optimization with several successful business ventures. As director of the Keller Center, which expands the scope of engineering education to include leadership and societal issues, Chiang is dedicated to cultivating the next generation of entrepreneurs.

Chiang, the Arthur LeGrand Doty Professor of Electrical Engineering, also leads the Princeton Entrepreneurship Advisory Committee, which was assembled by Provost David Lee and convened in January 2014 to explore ways to expand entrepreneurship opportunities for students, faculty members and alumni.

In this interview, he emphasizes that not all entrepreneurship is about technology.

How do you define entrepreneurship? Entrepreneurship doesn’t have to be commercializing some scientific or engineering product. It’s much broader than that. It’s a mindset that involves solving big problems through risk-taking actions with relatively few resources. You can be a social entrepreneur or a tech entrepreneur. You can found or join a startup. You can be an entrepreneur in the government, in a big corporation, in a nonprofit — in any organization. You can do it when you’re 22, or you can do it when you’re 92.

What has the committee learned so far from its “listening phase”? First, there is a surging interest from students to have the opportunity to be exposed to entrepreneurship. We also have extremely strong support from alumni. And we have learned that whatever the committee recommends, in the end, the hard work is going to boil down to the execution, and creative entrepreneurs working side by side to push, to pivot and to persist.

How can entrepreneurship connect to a liberal arts education? Our working definition of entrepreneurship is all about the broadening of the mind and training of the character. Interestingly, in our survey some of the strongest responses came from students and alumni in the humanities and social sciences. And there is a good reason for that. Entrepreneurship, unlike certain types of technology jobs, is fundamentally about your intrinsic capability and mindset, and not about a particular kind of vocational skill. We hope to expose students and faculty to the possibilities of entrepreneurship, to enable those who choose to become entrepreneurs, and to enhance the overall education and research environment at Princeton.

–By Molly Sharlach

Focus on undergraduate research: Power grid solutions in Nigeria

Oladoyin Phillips

For her senior research thesis, Oladoyin Phillips, Class of 2014, explored solutions to the electricity shortage in her home country, Nigeria. (Photo by Christopher Kwadwo Ampofo Gordon)

GROWING UP IN LAGOS, NIGERIA, Oladoyin Phillips was accustomed to the power outages that struck just as she was about to use her computer or charge her cellphone. “I was frustrated on those afternoons,” she said, “but I would remind myself that I was lucky because many Nigerians have no access whatsoever to electricity.” When it came time to select an independent research project for her senior thesis, required of all Princeton undergraduates, Phillips chose to examine solutions to Nigeria’s power problems.

Although home to vast stores of oil and natural gas, Nigeria delivers just 2 percent of the electricity typically needed to serve a nation of 168 million inhabitants. Over the last few years, the Nigerian government has privatized the power industry with the goal of improving its efficiency. But Phillips noticed that while Nigeria’s plan called for new power plants, it failed to address bottlenecks in the electricity supply chain. “I saw the opportunity to look at the entire system, from generation to transmission, and to develop strategies for improving the power sector,” she said.

Using skills she acquired while majoring in operations research and financial engineering, Philips analyzed large systems by gathering data and creating computer models. She focused on the natural gas-fired power plants that produce 80 percent of the country’s electricity (the remaining 20 percent is from hydroelectric power).

Warren Powell, professor of operations research and financial engineering, was Phillips’ adviser. “She is the kind of person who, given a few years, could have a real impact,” he said.

Using daily reports compiled during 2013 by the Transmission Company of Nigeria, a publicly owned company appointed to run the power grid, Phillips built a model that simulated the flow of energy from the fuel source to electricity generation, through the national transmission grid, and to distribution points just prior to consumer delivery.

From her analysis emerged a large-scale picture of the bottlenecks at each stage of the chain. One of the surprising findings was that most plants did not operate at full capacity, either due to maintenance issues or a shortage of natural gas. Nigeria has the largest proven natural gas reserves in Africa and the ninth largest in the world, according to the U.S. Energy Information Administration, but there are not enough gas plants or pipes to bring the fuel to the plants.

Phillips also found that Nigeria’s transmission network was too limited to serve the existing power generated, let alone the planned expansion. The transmission lines were also organized as a radial system with few or no alternative routes for electricity to travel when blockages or backups occur.

Her conclusion: Fix existing bottlenecks before building new plants. “The first and most crucial goal while making investments in the power sector should not be to increase the available capacity in the country,” she concluded, “but rather to ensure firstly, that all of the capacity that is already available, is delivered to the end users.”

Phillips graduated with a Bachelor of Science in Engineering in 2014 and is working at an energy and transportation company based in India.

–By Catherine Zandonella


Philosophical differences: What does physics tell us about the real world?

IN COLLEGE, PROFESSOR OF PHILOSOPHY Hans Halvorson was dismayed by the idea of having to choose between science and the humanities, so he blazed his own path, combining philosophy with physics and mathematics.

Why are philosophers fascinated by science? As a cultural phenomenon, we cannot ignore the power of science. It has transformed our world into what we know today. But I believe it is not the only source of knowledge. A lot of what we know comes through ordinary life experiences.

What questions are you working on? I’m interested in what physics tells us about the real world. There are two opposing views. One view is that our theories perfectly describe the reality we see around us — this is known as realism. But there are many cases where what we thought we knew from science turned out to be wrong, for example when Einstein’s theory of relativity trumped the Newtonian view of space and time. The opposing view is called antirealism, and says that physical theories are good at making predictions that we can use in our technologies, but they do not describe reality. I take the view that there must be something right on both sides, and that there may be a way to translate one view to another. A question I am looking at now is whether two competing theories of the structure of the universe, string theory and quantum loop gravity, have a common core.

How does your training help you think about these ideas? My Ph.D. dissertation was on the foundations of quantum mechanics. But I wanted to do something new, and I was fortunate to receive an Andrew W. Mellon Foundation award that enabled me to spend a year at the Mathematical Research Institute at the University of Utrecht in the Netherlands learning an area of mathematics known as category theory. Now I am applying these concepts to the philosophy of science and the debate between realism and antirealism.

How is this of value to the public? I think part of my job is to help people understand how science fits into their lives, especially in the United States where there is tension between science and religion. I understand the difficulty of reconciling beliefs with what we learn from science. But it is also not good to just believe what science says, because it is always changing. Science is full of unknown discoveries.

–By Catherine Zandonella

Math and music spark student’s research interests

Alexander Iriza

Alexander Iriza. Photo by Denise Applewhite

WHILE PRINCETON SENIOR Alexander Iriza, of Astoria, New York, credits his parents for sparking his interest in math — his mother gave him math workbooks when he was a toddler — that was merely “a nudge” in the right direction.

For his senior thesis, required of all Princeton undergraduates, Iriza worked with Yannis Kevrekidis, the Pomeroy and Betty Perry Smith Professor in Engineering, to examine specific data analysis techniques.

“The idea is to start with a dynamical system of many particles that interact with each other on the microscopic level,” Iriza explained. “It’s believed that many animal species in the wild operate in this way, with each organism having its own personal preferences but also reacting to the individuals in its vicinity. Then we seek to understand the often beautiful and complex behavior that emerges at the macroscopic level of the entire flock.”

Iriza was also a violinist in the University orchestra. His exceptional scholarship led to his being named salutatorian for the Class of 2014, delivering a speech in Latin at Commencement. Comparing the maturity and depth of Iriza’s work to that of a strong graduate student, or even a postdoc or colleague, Kevrekidis said: “His intellectual strength, his work ethic, his joy in discovery and thinking, [and] his own vision about research directions single him out among the wonderful students I have had the good fortune to work with in my 28 years in Princeton. I truly look forward to finding out what he will accomplish in his research life.”

–By Jamie Saxon

Emotional map illuminates an iconic rock song

Gilad Cohen

Gilad Cohen, a graduate student in music composition, analyzed the songs of the English rock band Pink Floyd. (Photo by David Kelly Crow)

IN A TYPICAL ROCK SONG, a few chords and a simple rhythm form the foundation for catchy lyrics that carry the listener along for three or four minutes. Expand these elements into a 20-minute song, and the result should be boring.

Yet songs of this length were common for progressive rock bands in the late 1960s and 1970s. Most of these extra-long songs were actually collections of “sub-songs” — sequences of disparate musical ideas, according to Gilad Cohen, a graduate student in music composition. As part of his dissertation research, Cohen analyzed the expanded songs of the ever-popular English rock band Pink Floyd.

The 1975 Pink Floyd song “Shine On You Crazy Diamond” is 26 minutes long. “And it’s all in the same key,” Cohen said. “The rhythm is very simple. You have a few chord progressions, and they just repeat themselves again and again.”

But the song is anything but boring. “There’s a very clever, detailed arrangement process that makes this music interesting, and allows it to maintain momentum throughout a long stretch of time,” Cohen said. The arrangement includes motivic development — the alteration or repetition of a motif throughout a piece of music — and the layering of instruments, in addition to the use of studio effects such as reverb and delay, innovative tools at the time.

“Shine On You Crazy Diamond” is a tribute to Syd Barrett, Pink Floyd’s former leader. Barrett left the band in 1968 due to mental illness, which was likely exacerbated by his use of LSD and the intense pressure he felt to create hits. Cohen views the song as an emotional journey through the stages of grief, an expression of the band’s sense of loss.

A "bereavement map" for Pink Floyd's "Shine On You Crazy Diamond" reveals which parts of the song express each of the five stages of grief - numbness, yearning, anger, mourning and acceptance.

A “bereavement map” for Pink Floyd’s “Shine On You Crazy Diamond” reveals which parts of the song express each of the five stages of grief – numbness, yearning, anger, mourning and acceptance.

To better understand how the sounds reflect these emotions, Cohen created a “bereavement map” showing which parts of the song express each of the five stages of grief — numbness, yearning, anger, mourning and acceptance. Like the real grieving process, the progression is not exactly linear.

Numbness, for example, is represented by drawn-out, improvised keyboard and guitar solos built around a single chord. Then, the guitar plays the song’s famous four-note “yearning motif,” in which the last note doesn’t quite belong with the rest. “It sounds like it wants to go somewhere,” Cohen said. “Pink Floyd is amazing at creating this tension.” Later, the same melody is played in two different rhythms, which alternately impart feelings of yearning and anger.

“Rock music is starting to have its day in the sun in musicological scholarship,” said Scott Burnham, the Scheide Professor of Music History and Cohen’s dissertation adviser. “Gilad’s work is timely, and it’s coming from a really great place — namely, his work as a musician and composer.”

Cohen shared his passion for Pink Floyd by organizing the first academic conference on the band’s music, “Pink Floyd: Sound, Sight and Structure,” which was held at Princeton in April 2014, and was co-organized by Dave Molk, a fellow graduate student in composition. The event’s keynote speaker was James Guthrie, Pink Floyd’s producer and engineer.

Cohen said he was inspired by the reactions of students, scholars and “hardcore fans” who attended the conference. “They’re really starved for this kind of knowledge. They listen differently to the music now,” Cohen said. “If I can expand someone’s enjoyment of music they’ve listened to throughout their lives, that’s a big thrill.”

–By Molly Sharlach

How to train your worm to explore the circuits involved in learning

Angelina Sylvain

Angelina Sylvain, a graduate student in the Princeton Neuroscience Institute, trains C. elegans roundworms to associate food with the smell of butterscotch for her studies of the neural circuits involved in learning and memory. (Photo by Molly Sharlach)

AS AN UNDERGRADUATE, Angelina Sylvain was fascinated to learn that devastating declines in cognition and muscle coordination could be caused by changes in a single gene — the cause of Huntington’s disease. She was intrigued by the fact that brain surgery on an epileptic patient cured him of seizures, but wiped out his ability to form short-term memories.

These remarkable discoveries first drew Sylvain to the field of neuroscience, though she never imagined that her own efforts to understand the human brain would involve training tiny worms.

A fourth-year graduate student in the Princeton Neuroscience Institute, Sylvain seeks to understand how the activities of neurons in the brain lead to particular behaviors and memories.

“The problem with studying the human brain is that we have 86 billion neurons,” she said. “But worms have only 302. And they’re transparent, so you can use imaging techniques to indirectly observe the activities of neurons.”

The millimeter-long roundworms, known by the scientific name Caenorhabditis elegans, can be found squirming underfoot in temperate environments. In the lab, they swim in petri dishes and feast on E. coli bacteria. Working with Coleen Murphy, an associate professor of molecular biology and the Lewis-Sigler Institute for Integrative Genomics, Sylvain teaches the worms to associate food with the scent of butanone, a chemical that smells like butterscotch.

During the training process, Sylvain tracks the activation of individual neurons as the worms learn to identify and move toward the alluring odor. She uses specially engineered worms in which specific neurons glow green in response to calcium ions, hallmarks of neuron activation. At first, only a sensory neuron lights up when the worms smell butanone. But after the worms learn to associate butanone with a meal, Sylvain can detect the activation of an entire neural circuit — a sensory neuron, an interneuron and a motor neuron. The motor neuron leads the worm to swim toward the scent.

By training the worms, Sylvain hopes to answer basic questions about how long-term memories are formed. She plans to examine the numbers and combinations of neurons required to establish memories, as well as the adaptability of memory-forming pathways. By eliminating specific neurons, she can test whether the worms can still form memories, and how the circuits change.

Sylvain relishes both the challenges and the rewards of academic research. “Academia offers a fantastic combination of the ability to teach and mentor, and also to ask awesome research questions,” she said. “It’s always a struggle when experiments fail. But when things finally work out, there’s a great sense of satisfaction that you’ve uncovered something nobody else knows.”

Coleen Murphy’s research group is funded by the National Institute on Aging of the National Institutes of Health.

–By Molly Sharlach

Study casts doubt on fairness of U.S. democracy

Affluence and Influence

Affluence and Influence (Princeton
University Press, 2013)

AFFLUENT INDIVIDUALS AND BUSINESS CORPORATIONS have vastly more influence on federal government policy than average citizens, according to research by Princeton University and Northwestern University.

The researchers used a data set comprised of 1,779 policy issues over a 30-year period to estimate how much influence affluent citizens, organized interest groups and ordinary citizens each have on policy outcomes. They found that affluent citizens, those at the 90th-income percentile, have the most influence, followed by organized interest groups. However, the preferences of average citizens have no discernable, independent effect on policymaking at all, the researchers found.

“If democracy means that all citizens should have a say in shaping government policy, our findings cast doubt upon just how democratic U.S. policymaking actually is,” said Martin Gilens, a professor of politics at Princeton and a member of the executive committee of the Center for the Study of Democratic Politics at the Woodrow Wilson School of Public and International Affairs. He conducted the study, for the fall 2014 issue of the academic journal Perspectives on Politics, with co-author Benjamin Page, the Gordon Scott Fulcher Professor of Decision Making at Northwestern University.

Gilens is the author of the 2013 prize-winning book Affluence and Influence (Princeton University Press).

–By B. Rose Huber

New mineral: Steinhardtite


Steinhardtite is a mineral named in honor of Paul Steinhardt, Princeton’s Albert Einstein Professor in Science and a professor of physics (Image courtesy of Luca Bindi, et al)

A MINERAL DISCOVERED to be of meteoritic origin has been named “steinhardtite” in honor of Paul Steinhardt, Princeton’s Albert Einstein Professor in Science and a professor of physics. The name was approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association.

The mineral was found in the Koryak Mountains in Russia’s Kamchatka Peninsula during a 2011 expedition led by Steinhardt to locate the meteoritic source of the first known naturally occurring example of a quasicrystal, now known as “icosahedrite,” in which the atoms are arranged in patterns that do not regularly repeat and include unlikely configurations such as the 20-sided shape of a soccer ball. Steinhardt and collaborators had discovered a sample of icosahedrite at the Natural History Museum at the University of Florence, Italy, a finding published in the journal Science in 2009, and later identified the Florence sample as being meteoritic in origin. The expedition to the Koryak Mountains resulted in the discovery of steinhardtite, a new crystalline form of aluminum combined with significant amounts of iron and nickel.

The international team reporting the mineral and proposing the name was led by Luca Bindi, professor of mineralogy and crystallograpy at the University of Florence. Princeton researchers included Nan Yao, director of the Imaging and Analysis Center at the Princeton Institute for the Science and Technology of Materials (PRISM); Gerald Poirier, PRISM senior research specialist; Lincoln Hollister, professor of geosciences, emeritus; and Chaney Lin, a graduate student in physics. They were joined by Glenn MacPherson, a geologist at the Smithsonian Institution; Christopher Andronicos, an associate professor at Purdue University; scientists Vadim Distler, Valery Kryachko and Marina Yudovskaya of the Russian Academy of Sciences; Michael Eddy, a graduate student at the Massachusetts Institute of Technology; Alexander Kostin, a geosciences technologist at BHP Billiton; and William Steinhardt, a graduate student at Harvard University.

-By Catherine Zandonella

A farewell to arms? New technique could aid nuclear disarmament

A Farewell to Arms?

A new method that borrows from strategies used in computer cryptography could verify the presence of nuclear warheads without collecting classified information. The technique fires high-energy neutrons at a non-nuclear target (pictured above), called a British Test Object, that will serve as a proxy for warheads. (Photo by Elle Starkman)

SCIENTISTS at Princeton University and the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) are developing a system to verify the presence of nuclear warheads without collecting classified information, as a step toward the further reduction of nuclear arms.

While efforts have been made to develop systems for verifying the content of warheads covered by disarmament treaties, no such methods are currently in use. The new method borrows from strategies used in computer cryptography to identify nuclear warheads while learning nothing about the materials and design of the warheads themselves.

The research was published in the June 26, 2014, issue of Nature and was conducted by Alexander Glaser, an assistant professor in Princeton’s Woodrow Wilson School of Public and International Affairs and the Department of Mechanical and Aerospace Engineering; Robert Goldston, former director of PPPL, a fusion researcher and a professor of astrophysical sciences at Princeton; and Boaz Barak, a senior researcher at Microsoft New England who has taught computer science at Princeton.

–By John Greenwald