TR 35

Technology Review’s top 35 innovators under the age of 35

Technology Reviewarchive page

October 1, 2005

Their work is a road map to what’s hot in emerging technology – and their achievements will shape the world we live in for decades to come.

They are inventors and discoverers and entrepreneurs. They are chemists and biologists and software engineers and chip designers. They create their wonders in universities, startups, and large corporations. They gravitate to the most interesting and difficult scientific and engineering problems at hand, and arrive at solutions no one had imagined. They take on big issues. They are the TR35 – Technology Review’s selection of the top technology innovators under age 35 (as of October 1, 2005). The winners from previous years (when it was the TR100) have changed your world. So will the people you’re about to meet.

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Contributing editors and writers:
TR35 Project Editor: Herb Brody
Profile Writers:
Erika Jonietz
Eric Hellweg
Michael Fitzgerald
Deborah Asbrand
Corie Lok
Neil Savage
Stu Hutson
David Talbot
Lisa Scanlon
Sally Atwood
Ken Garber

Daniel Riskin, 33
UCLA Medical Center
Developing devices for wound closure and early heart-attack intervention

In addition to working about 80 hours a week as a surgical resident at the University of California, Los Angeles, Medical Center, Daniel Riskin is building companies to develop and market new medical devices. “Physicians have an obligation to innovate,” says Riskin.

While training to be a doctor at Boston University and Tufts University, Riskin dabbled in technology development, writing software to help physicians manage their practices and researching different designs for surgical clips with a medical-device company. But he wanted to do more – to come up with his own inventions and bring them into widespread use. Thus he enrolled, partway through his residency, at MIT’s Sloan School of Management. While studying for his MBA, he kept up his operating-room skills by working at private surgical practices on evenings and weekends.

After graduating from Sloan, Riskin was named the first fellow in Stanford University’s new surgical-innovation program. At Stanford, he and his collaborators developed an elastic, adhesive, polymer-based patch that they hope will provide a less painful alternative to staples or stitches as a way to close up wounds and surgical incisions. He is now forming a company to commercialize the patch, which he expects will also reduce scarring.

Riskin also helps doctors with few business skills or little experience to become innovators themselves.

Last year, Riskin, along with Michael Laposata, director of clinical laboratories at Massachusetts General Hospital in Boston, started a company, MedPacks, to develop portable diagnostic tests and medications that patients could use at home – before getting to the emergency room – if they thought they were having heart attacks. Such early treatment could lower the risk of death or complications by as much as 50 percent. “If we’re going to do anything innovative,” says Laposata, “we’re going to need more Dans.”

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Jia Chen, 33
IBM Watson Research Center
Looking past silicon to carbon nanotubes

Eventually, semiconductor manufacturers won’t be able to cram any more transistors onto silicon chips. So Jia Chen is working on an alternative: electronic circuits and devices that use cylindrical, nanometer-wide carbon molecules called carbon nanotubes. Among their other advantages, some types of nanotubes can conduct electricity 100 times better than silicon.

So far, most transistors made out of carbon nanotubes have been p-type, meaning they use positive charge carriers; negative – n-type – nanotube transistors have been much more difficult to produce. Chen, however, has found a simpler way to make them, which could be an important step toward integrating carbon nanotubes into conventional electronics. Chen discovered that attaching certain kinds of molecules to nanotubes would add electrons to them or draw electrons out, yielding either p- or n-type devices.

Another problem with nanotube transistors is their need for metal electrodes, which are necessarily much larger than the nanotubes. The size difference tends to cause current leakage, reducing electrical efficiency. Chen found she could add certain impurities to a small segment of a nanotube to allow the nanotube to serve as an electrode, but one with little leakage. Her nanotube transistors carried 100 times as much electrical current as previous ones.

The properties of nanotubes vary depending on their diameters. Choosing a particular diameter causes a tube to emit light at a particular wavelength. Chen was able to control the positive and negative charges in a nanotube to make it emit light 100 times brighter than the light from earlier devices. This could give nanotubes the ability to serve as optical interconnects – transmitting data among circuits more efficiently than copper does. Eventually, every device on a chip could be made from nanotubes. “Imagine a circuit with the same material acting as sensors, transistors, light emitters, and also interconnects,” says Chen.

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Narasimha Chari, 31
Tropos Networks
Setting the mesh networking standard

In the late 1990s, when Wi-Fi-equipped laptops were still a novelty, Narasimha Chari saw the possibility of creating large communications infrastructures using wireless mesh networks – which at the time were the exclusive province of the military. In 18 months of moonlighting while a physics grad student at Harvard University, he created elegant algorithms that tailored mesh networking for routine civilian communications.

Tropos Networks, the company Chari founded in 2000 with coinventor Devabhaktuni Srikrishna, helped launch commercial wireless mesh networking. With their straightforward installation – routers attach to lampposts – and attendant low cost, mesh networks have eased into plentiful use both outdoors (on campuses, in public safety networks, and at gatherings such as festivals) and in (in hospitals and factories). But Tropos is focusing on the rapidly growing market for networks that serve entire municipalities. That’s the application of choice for one-third of the company’s 200 customers.

Tropos’s services, which are built around Chari’s routing protocols, dominate the nascent mesh-networking industry. Telecommunications companies fear the proliferation of the technology, seeing it as a threat to their Internet access businesses. In fact, the telecommunications industry is lobbying for legislation granting them – not local governments – first dibs on municipal Wi-Fi installations. Meanwhile, Tropos is gaining customers at a rapid clip; 75 signed on in the first half of 2005.

Tropos’s expansion is bringing Chari full circle. In 1992, after receiving the third-highest score out of 80,000 on the Indian Institutes of Technology entrance exam, Chari left India for Caltech. Later, while at Harvard, he had late-night talks with Caltech pal Srikrishna about providing anytime, anywhere communications in developing countries. Now, as Tropos ships its first systems to India, Chari is seeing his innovation connect back to his homeland.

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Parham Aarabi, 29
University of Toronto
Sharpening a computer’s listening skills

Computers have difficulty doing what the brain does easily: concentrating on one voice while ignoring other sounds. University of Toronto electrical-engineering professor Parham Aarabi created an algorithm that calculates the difference between the times at which a sound reaches two closely spaced microphones. Based on the delay, the software can determine the direction of speakers and amplify the speech of any one of them; all other conversation is reprocessed into a slight hum. Aarabi’s invention, which is 30 percent more accurate than other multimicrophone systems, could filter out extraneous voices in cell-phone conversations or enhance voice control in cars.

Vladimir Aksyuk, 33
Lucent Technologies’ Bell Labs
Making tiny mirrors for laser beams

Vladimir Aksyuk made a name for himself in the world of microelectromechanical systems in 1999 when he spearheaded the development of Bell Labs’ all-optical switch – the first commercial device to use thousands of tiny rotating mirrors to intricately manipulate optical communications signals without converting them into electrical pulses and back. Its performance was 16 times faster than that of the best of its electrical counterparts.

Aksyuk has since expanded on that technology to create systems featuring arrays with mirrors as small as 100 micrometers across, each one capable of not only rotation but also up-and-down motion. These arrays enable extremely precise control of laser beams, which is crucial to the U.S. military’s program to develop a secure, high-bandwidth laser communication system for aircraft, ground bases, and even space vehicles.

The arrays may also soon change how microchips are produced. The Russian-born Aksyuk is heading a project at Bell Labs to use micromirrors to carve out microchips without the costly “masks” – basically, stencils patterned with circuit designs – that are currently used to optically etch chips. Not only could this lower production costs and time, but it could also extend the lifetime of Moore’s Law.

Regina Barzilay, 34
MIT
Teaching computers to read and write
For her doctoral dissertation at Columbia University, computer scientist Regina Barzilay led the development of Newsblaster, which does what no computer program could do before: recognize stories from different news services as being about the same basic subject, and then paraphrase elements from all of the stories to create a summary.

Though humans can easily divine the meaning of a word from its context, computers cannot. Barzilay uses statistical machine-learning software to teach computers to make educated guesses. A computer is fed pairs of text samples that it is told are equivalent – two translations of the same sentence from Madame Bovary, say. The computer then derives its own set of rules for recognizing matches. Once trained, it can tackle new sentences, computing “syntactic trees” that parse out their structural elements in different ways and determining the probability that each interpretation is correct. Then it statistically compares the most likely trees from two sentences to see if they match. The Newsblaster software recognizes matches about 80 percent of the time.

The software works best with news stories, because they exhibit some regularity; “the problem is more constrained,” says Barzilay, now an MIT assistant professor of electrical engineering and computer science. She’s working on a variation of Newsblaster for spoken language, which could yield applications that range from summarizing recorded lectures to handling airline reservation calls.

Helen Blackwell, 33
University of Wisconsin
“Talking” bacteria out of causing infections

The main cause of death among cystic-fibrosis patients, and a threat to many burn victims and AIDS patients as well, is the bacterium Pseudomonas aeruginosa. But the microbe is not a health problem until enough of the bacteria join together to form a gooey amalgamation called a “biofilm.” Almost 80 percent of bacterial infections are in biofilm form. Helen Blackwell, an assistant professor of chemistry, studies quorum sensing – the communications mechanism that tells bacteria that they have replicated enough to form a biofilm. It’s easy, according to Blackwell, to synthesize the organic molecules that bacteria use to talk to each other.

Blackwell is testing a series of such messenger molecules to see if she can hijack the bacteria’s communications network. So far, of the hundreds of molecules she has screened, 10 seem promising. The right molecule might fight a hard-to-treat infection or induce a small, early infection to stimulate the body’s immune response. Blackwell’s group developed a way to speed up the reaction that produces the messenger molecules by heating it with microwaves. “We reduce a reaction sequence from about three days to about 45 minutes,” she says.

Thijn Brummelkamp, 30
Whitehead Institute for Biomedical Research
Silencing the genes that cause cancer

Amassing detailed information about which human genes play a role in cancer and what their roles are is central to many efforts to fight the disease. One of the most promising new approaches to the identification of cancer-causing genes is called RNA interference, a method for suppressing genes to learn their functions. But RNAi is costly, and silences genes for only a few days at a time – not long enough for researchers to study slow-developing diseases. Thijn Brummelkamp has developed an inexpensive way to make the effect last, silencing a single gene indefinitely. Brummelkamp’s work “will lead to new treatments” for cancer, says MIT biologist and Nobel laureate Phillip Sharp.

Martha Bulyk, 33
Harvard Medical School
Discovering how genes are regulated

Figuring out how genes coordinate the complex phenomena of life involves more than deciphering a DNA sequence. Proteins called transcription factors control genes by attaching to DNA; discovering where each of these proteins binds is critical to understanding how genes regulate working cells. Martha Bulyk has taken the gene chip technology originally developed to measure gene activity and adapted it to determine the DNA binding preferences of proteins. The technology replaces painstaking assays with efficient screens, which could aid research on diseases that are affected by mutations in transcription factors or in their binding sites, such as hypertension, cancer, and diabetes.

Stewart Butterfield, 32
Flickr (Yahoo)
Building communities through photos

In February 2004, Stewart Butterfield and his coworkers at Ludicorp, then engaged in developing an online game, launched a side product called Flickr – “kind of on a lark.” By summer, the project had taken over the company; today it’s the Web’s fastest-growing photo-sharing site. Employing “tags” that allow people to make their photos searchable by content, Flickr encourages users to engage in discussions about their pictures. Acquired by Yahoo in March, Flickr now has more than one million users, who post hundreds of thousands of new photos a day.

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George Candea, 30
Aster Data Systems
Protecting software from crashes

As counterintuitive as it might seem, George Candea’s “crash-only software” concept may actually help keep software crash free. According to Candea, software crashes and subsequent reboots needn’t be catastrophic, systemwide events. He has described software that can be trained to monitor itself and, if it detects something amiss, to launch a surgical, or “micro,” reboot of just the problematic application element, while the system as a whole functions uninterrupted. “Microrebooting allows software to react to failure in machine time as opposed to human time,” says Candea, who recently got his doctorate in computer science at Stanford University.

Bryan Cantrill, 31
Sun Microsystems
Tracing software in real time

Even with all the recent advances in information technology, systems administrators are still running blind: if a piece of software doesn’t quite do what it should, administrators may spend days hunting down the problem and figuring out how to fix it. Bryan Cantrill, senior staff engineer at Sun Microsystems, has created an application called DTrace that offers real-time software diagnostics – giving IT folks a way to see what’s going on and start improving performance in minutes. This kind of power elates many programmers. “With DTrace,” says Cantrill, “I can walk into a room of hardened technologists and get them giggling.”

Andy Carvin, 34
Digital Divide Network
Bringing Internet power to the have-nots

As founding editor in 1999 and current director of the Digital Divide Network, Andy Carvin has helped build an online community of more than 7,500 technology activists, educators, small-business owners, and policy makers. Their mission is to devise remedies for the fundamental information-age inequity: most people in the world lack the ability to access the Internet or the skills to use it. Carvin is also promoting a way for technology to give voice to the disenfranchised: mobcasting.

Carvin’s idea is to combine the ubiquity of cell phones with the ease of posting information to Web logs (blogs). Say protesting human-rights activists get roughed up by police, with no traditional media on hand to record their plight. Over their phones, the human-rights activists could send multiple reports on what’s happening – either audio or video – to the same website. Carvin is pushing programmers to create mobcasting software that works outside the U.S. phone system. With the use of mobcasting, suggests Carvin, “suddenly, the very people who are victims are empowered to bear witness to the world almost instantaneously.”

Bram Cohen, 29
BitTorrent
Upending the file-sharing world, bit by bit

Bram Cohen’s creation, BitTorrent, answers a deceptively simple question: if someone requests a file over a network, and multiple people on the network possess the file, why should only one person send the file in its entirety to the requester? Cohen’s revolutionary solution: send tiny chunks of the file from multiple users, eliminating the bandwidth crunch that results when a single user sends a large file in its entirety. A 400-megabyte video file that could take hours for a single user to distribute can be broken up into thousands of pieces, each of which takes only a few seconds to send. The impact of the technology that Cohen developed goes far beyond the world of illicit file-swapping: game companies and Linux developers are now experimenting with BitTorrent distribution as well.

Cohen is humble about his creation and its potential impact. It is, he says, “just a way to move bits around.”

Dennis Crowley, 29
Dodgeball
Moving online socializing into the streets

When Dennis Crowley goes out clubbing in New York, he’ll text a message with his location to Dodgeball, the company that he founded. Crowley’s message – “@ Luna Lounge,” for example – goes out to all the friends he has listed at the Dodgeball website. The company’s computer checks the club’s address against its list of geographical locations in 22 cities. If someone who is not on Crowley’s friend list but is on the list of one of his friends has checked in within the last three hours and a 10-block radius, the computer notifies both parties. If Crowley has listed a girl he doesn’t know as a “crush,” she’ll get a message with his picture saying he’s interested. She’ll have the option to find him or dodge him, without his ever knowing where she is. Google liked the idea so much it bought Dodgeball in May. Crowley says it’s “a very powerful thing to know where your friends are all the time.”

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Matthew DeLisa, 32
Cornell University
Delivering more medicine from microbes

Each year, billions of dollars’ worth of drugs, from insulin for diabetics to the stroke drug tPA, are made in huge vats full of microbes engineered to produce human proteins. The process is both inefficient and enormously expensive. Matthew DeLisa, an assistant professor of chemical and biomolecular engineering, was the first scientist to use a twin arginine translocation (Tat) pathway to produce human proteins. This should mean cleaner proteins and longer-lived cultures.

DeLisa is also modifying bacteria to improve each step in protein production. His focus, he says, is “the engineering of biological machines to tackle problems that nature itself can’t do.” Until recently, the biotech industry focused on changing the growth environment for bacteria to boost protein productivity, but DeLisa is supercharging production by going inside the cell itself. For example, he’s replacing key parts of the bacteria’s protein-making machinery with components from higher organisms to produce finely tuned miniature drug factories.

Kevin Eggan, 31
Harvard University
Using cloning to study degenerative diseases

While earning his PhD, Kevin Eggan helped make Rudolf Jaenisch’s lab at the Whitehead Institute for Biomedical Research a preeminent cloning lab. Eggan became “arguably the most skillful mouse cloner in this country,” says Jaenisch. Eggan used those skills to clone mice from neurons, proving that animals could be cloned from even the most specialized cells in the body – a feat that many scientists considered impossible. Eggan also helped explain how cloning “reprograms” the genetic material from an adult mouse cell, identifying the changes that take place to reset the nucleus to the beginning of development.

Eggan, now an assistant professor of molecular and cellular biology, plans to create human stem cell lines from patients with neurodegenerative disorders such as Parkinson’s and Lou Gehrig’s diseases, in order to study disease development and search for new drugs. He has also begun studying nuclear reprogramming in human cells in the hope of finding a way to create patient-specific embryonic stem cells without using human eggs.

Anita Goel, 32
Nanobiosym
Building novel pathogen detectors

Physicist and physician Anita Goel finds inspiration in the tiny: the proteins that inch their way along DNA, reading and copying the genes inside every cell. As a physics graduate student at Harvard University, Goel developed a theory to explain how these molecular motors work. While working on her medical degree at Harvard in 2004, she founded Nanobiosym to apply her theories to the development of nanotech devices for precisely controlling these proteins; such devices could identify viruses and bacteria in, say, a blood sample more rapidly, accurately, and cheaply than current techniques can. Her goal: a low-cost, handheld device for biodefense and biomedical applications.

Saul Griffith, 31
Squid Labs
Following inspiration for inventing

Before Saul Griffith perfected his five-minute method for making custom-crafted lenses for $5, he volunteered in South America, where he once had to hand a pair of dainty granny glasses to a six-foot-tall man: they were the only pair the volunteer group had that fit the man’s prescription, he recalls. And it was from kite-surfing, a sport that relies on the strength of the ropes tethering a surfer to a wind-drawn parachute, that Griffith drew the idea for smart ropes, in which embedded conductive threads reveal developing weaknesses. After pursuing such ideas en route to his doctorate at the MIT Media Lab, he cofounded Squid Labs to explore the business of inventing. Among his projects: “open source hardware,” to do for computer equipment what Linux did for operating systems.

Paul Hergenrother, 33
University of Illinois at Urbana-Champaign
Discovering drugs that defy convention

Paul Hergenrother is a chemist who takes on huge, unsolved medical problems: antibiotic resistance, cancer, and neurodegenerative disease. His small-molecule compounds bind tightly to unconventional disease-related targets, deactivating them. For example, Hergenrother found compounds that eliminate plasmids, the DNA rings that deadly bacteria use to spread antibiotic resistance. That pioneering project led him to a general method for finding drugs that target a particular type of RNA – messenger RNA – as a way to silence disease-causing genes, something standard drugs can’t do. Hergenrother’s “ten-year vision” could lead to treatments for Alzheimer’s and Parkinson’s.

Katrine Hilmen, 34
ABB Corporate Research
Getting the most out of oil rigs

Katrine Hilmen is helping to keep dwindling North Sea oil fields productive. The chemical engineer at ABB’s research center in Norway developed innovative online monitoring and management tools for oil production platforms. Her technology monitors parameters such as heat, vibration, pressure, and flow rates, and can quickly identify a problem and its cause. The typical benefits: a 3 to 8 percent increase in oil production, a 10 to 15 percent reduction in operating expenses, and less pollution. Her innovations in process optimization, which have led to four patent filings, are widely studied by others in the field, enhancing their impact.

Tracey Ho, 29
Caltech
Scrambling bits for a more efficient Internet

Today’s Internet transmissions chop files into packets, each of which is passed from router to router until it reaches its final destination. But when files get big or are sent to many users, transmitting them without clogging the network becomes complicated. With “network coding,” an idea first proposed in 2000, routers would jumble together the bits from different packets, forming new packets. Recombining the data in this way gives the end user additional information, theoretically speeding downloads and increasing network capacity. But early network coding schemes required a godlike central authority that knew how the packets were to be combined – a practical impossibility.

As a PhD student at MIT, Tracey Ho had a novel alternative: let network nodes mix packets together at random, tagging them with just enough information to help end users’ computers recover the original data. This decentralized method automatically optimizes bandwidth use. “It sounds kind of insane,” says Muriel Medard, Ho’s PhD advisor. “But it’s not just that it works; you can’t make it work better.” As an assistant professor of electrical engineering and computer science, Ho still studies network coding. But only months after she first presented her “distributed random network coding” scheme, Microsoft researchers showed that it can clearly outperform today’s multicast systems. The company has embarked on a project called Avalanche to commercialize the scheme.

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Trey Ideker, 33
University of California, San Diego
Defining and advancing systems biology

As a graduate student, Trey Ideker published a paper that helped define the discipline of systems biology. His research goals today reflect those of the entire field: to integrate the myriad data that researchers can collect about a cell into coherent computer models. As an assistant professor of bioengineering, Ideker is not only improving these models but employing them in biological discovery. For instance, he is looking for protein networks uniquely present in pathogenic organisms; these could make good drug targets. He hopes that, ultimately, systems-derived models will let researchers simulate how potential drugs will affect the body – long before the compounds are tested in humans.

Hang Lu, 28
Georgia Institute of Technology
Designing microfluidic chips to study cells

Hang Lu has a flair for adapting to new environments. At 16, she moved from China to Colorado, where she excelled academically. As a postdoc, she applied her expertise in building bioMEMs – tiny devices that manipulate cells and microorganisms – to devising innovative experiments in neurobiology. Lu has designed minute mazes to test how microscopic worms learn using smell, and she constructed microscale gas gradients to help identify the sensory pathways that the worms use to detect oxygen levels. Now an assistant professor of chemical and biomolecular engineering, Lu hopes her continued worm work will yield clues to the workings of the human brain.

Samuel Madden, 29
MIT
Simplifying wireless sensor nets

Wireless sensor networks enable the remote monitoring of everything from the habitat of an endangered bird species to a building’s response to an earthquake. The problem, says computer scientist Samuel Madden, is that proper programming of the nets’ data-gathering “motes” can require months of expert attention. In 2003, while a graduate student at the University of California, Berkeley, Madden created software called TinyDB that translates high-level queries like “What’s the average temperature in the forest?” into precise instructions. Madden, an assistant professor of computer science, is now installing sensors in cars to monitor operating conditions and figure out faster routes.

Yael Maguire, 30
ThingMagic
Inventing across disciplines

A technological omnivore, Yael Maguire moves fearlessly among fields such as physics, engineering, biology, and software design. As a graduate student at MIT, he designed a sensor that makes the measurement of nuclear magnetic resonance between 10 and 100 times more sensitive but works on samples 1,000 to 10,000 times smaller than those required by current probes. Shuguang Zhang, associate director of MIT’s Center for Biomedical Engineering and Maguire’s thesis advisor, says the sensors will allow researchers to more easily obtain information valuable for designing new drugs.

While a doctoral student at the MIT Media Laboratory, Maguire cofounded ThingMagic, where he is now co-chief technology officer, and pioneered the use of software-defined radio for the radio frequency ID chips that help track retail inventory more quickly and accurately. Maguire’s software allows a single reader to scan and decode hundreds of tags at once, no matter which of the many existing data protocols they use. Maguire also cofounded ThinkCycle, a nonprofit that encourages technologists to collaborate on problems in developing countries.

Melissa Mahoney, 32
University of Colorado at Boulder
Making materials to treat brain damage

Nerve cell transplants offer tremendous promise for patients who are suffering the effects of stroke, or from Parkinson’s disease or other neurodegenerative illnesses. But experiments in rodents showed that about 95 percent of cells transplanted into the brain die before they can help the recipient. Melissa Mahoney is working to develop hydrogel materials that can house the cells, protecting them and supplying them with proteins that encourage their growth. In collaboration with scientists at the University of Colorado at Denver’s Health Sciences Center, Mahoney, an assistant professor of chemical engineering, plans to test these cell-loaded gels in rats within the next year.

Rajit Manohar, 33
Cornell University
Taking the clocks out of computer chips

The different functions of a computer chip are synchronized by an onboard clock, but that means the fastest operations can’t pass on their data until the slowest have finished. Rajit Manohar, an associate professor of electrical and computer engineering, speeds up chips and lowers power consumption by removing the clock; his chips are 10 times more energy efficient than previous clockless chips. Instead of a separate clock network carrying a global timing signal, Manohar’s chips use short wires to carry signals that alert successive operations when the previous operations have finished. Last year, Manohar also built the first low-power processor for sensor networks: “You only activate the part of the chip that’s doing the work you need,” he says. Such sensors could run on the same batteries for years instead of weeks.

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David Pennock, 34
Yahoo Research
Predicting the future of markets

How could markets possibly be able to predict things like where a hurricane will strike? In part because they aggregate information well, says David Pennock, who studies how economic theory can be expressed via computation. Pennock’s research underlies not only predictive markets but also the enormously successful sponsored search functions featured on Yahoo, Google, and elsewhere. Recommendation engines like those on Amazon.com also draw from Pennock’s work. Most recently, Pennock designed a new type of market, the “dynamic pari-mutuel market,” now being offered at Yahoo Tech Buzz. Part horse racing, part futures market, it lets people bet on whether a product is a fad or for real.

Matthew Rabinowitz, 32
Rosum
Giving GPS a sharper image

Inside buildings and the urban valleys of large cities, Global Positioning System technology is often inaccurate or unusable. Matthew Rabinowitz has sharpened GPS precision by exploiting the synchronization codes embedded in broadcast television signals. These codes allow a TV receiver to compile numerous signals into a single harmonious output. Rabinowitz, who cofounded Rosum and now serves as chief technology officer, has developed a handheld device that uses sync codes to calculate how far the user is from the source of the signals and thus determine his or her location. The Rosum technology refines GPS position readings to within a meter or two, even indoors and in cities.

Adam Rasheed, 31
GE Global Research
Pulsing the way to efficient aircraft engines

Adam Rasheed has made fundamental improvements to an aircraft propulsion system based on a pulsed-detonation engine – a technology in which a fuel-air mixture is compressed and exploded as many as 100 times per second. Pulsed detonation creates vastly higher pressures than the slower burn of a conventional engine’s combustion chamber, offering a theoretical 5 percent efficiency gain. Rasheed built a prototype that operates longer and without the oxygen enrichment required by other research efforts. And he was the first to use such technology in an important role: to drive the turbines that are at the heart of today’s jet engines.

Shiladitya Sengupta, 33
Harvard Medical School
Delivering drugs to cancer cells

As a master’s student in India, Shiladitya Sengupta developed an anti-inflammatory gel that’s now sold in India under the brand name Nimulid. During his doctoral studies at the University of Cambridge, he revealed how a protein that causes liver regeneration promotes blood vessel growth, and cofounded Dynamic Biosystems to turn the discovery into treatments for chronic wounds such as pressure sores. But a child’s toy – several small balloons encapsulated in a bigger one – inspired what may be his greatest innovation: a nanoscale device to treat cancer.

Sengupta’s drug delivery device, developed during his postdoc at MIT, consists of a lipid sphere about 200 nanometers wide surrounding smaller, biodegradable polymer spheres. These nanocells home in on cancers based on the unique characteristics of tumor blood vessels. The outer shells then dissolve, releasing a drug that destroys the vessels. As the cancer cells starve for oxygen, they secrete enzymes that break up the inner spheres, dispensing a standard chemotherapy agent. The nanocells have the potential both to treat tumors more effectively than existing regimes and to reduce side effects.

The nanocells have proved effective in mouse models of melanoma and lung cancer. Because Sengupta designed them using polymers and drugs already approved for human use, doctors can quickly move them into clinical trials. Now an assistant professor at Harvard Medical School and Brigham and Women’s Hospital, Sengupta is extending the concept to treat other diseases.

Francesco Stellacci, 32
MIT
Fabricating microarrays faster

Microarrays are slides dotted with hundreds of thousands of different gene segments that help researchers spot particular DNA sequences – making microarrays invaluable tools for the study of genetically influenced diseases ranging from diabetes to many forms of cancer. But current methods for manufacturing microarrays are very costly and time consuming because of the dozens of printing steps they require. Materials science assistant professor Francesco Stellacci may have found a way to quickly produce microarrays for as little as $50. In his approach, a single strand of DNA “stamps” genetic information into a slide, which can then serve as a master template for the production of multiple identical arrays.

Adam Stubblefield, 24
Johns Hopkins University
Unlocking digital doors

Adam Stubblefield has become a champion at finding holes in supposedly secure systems. He proved that an early version of the wireless security protocol WEP was not secure, and helped crack the Secure Digital Music Initiative’s electronic watermark. Stubblefield also helped reveal security flaws in Diebold’s voting machine software – the first serious security review of the electronic-voting-machine’s code, according to Cindy Cohn, legal director of the Electronic Frontier Foundation.

Most recently, Stubblefield reverse-engineered a radio frequency ID cipher. Yet he modestly notes he’s not much of a programmer and has yet to learn to speak a foreign language. “My brain isn’t very good at many things,” says Stubblefield, who received his doctorate from Johns Hopkins in the spring. But his brain is helping keep information systems from being used to encroach on civil liberties – a good thing indeed.

Haitao Zheng, 30
University of California, Santa Barbara
Tuning in “cognitive radios”

At 15, Haitao Zheng stood out at China’s competitive Xian Jiaotong University for both her youth and her brilliance. Today, her work on so-called cognitive radios stands out for its potential to make a promising technology practical. Using software, cognitive radios dynamically detect and exploit unused radio frequencies; the devices could alleviate competition for the ever shrinking amount of unassigned radio spectrum. To be truly useful, though, a cognitive radio must not only detect free spectrum but also select the best frequency for a given function, all without interfering with other devices. At Microsoft Research Asia, Zheng created algorithms that allow disparate devices to “negotiate,” automatically allocating the available spectrum efficiently and fairly. Zheng is continuing her research on open spectrum systems as an assistant professor of computer science at the University of California, Santa Barbara.

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TR35 Judges

Howard Anderson Managing director, YankeeTek Ventures
Gordon Bell Senior researcher, Microsoft’s Media Presence Research Group
*Alexis Borisy Founder, president, and CEO, CombinatoRx
*Aref Chowdhury Member of technical staff, quantum information and optics research department, Lucent Technologies’ Bell Laboratories
Joe Chung Cofounder, Art Technology Group
James Collins Professor of biomedical engineering, Boston University
Sanjay Correa Global technology leader for energy and propulsion technologies, General Electric Global Research
Irene Greif IBM fellow and department group manager, Collaborative User Experience, IBM
Bill Joy Partner, Kleiner, Perkins, Caufield, and Byers
*Christina Lampe-Onnerud, CEO, Boston-Power
Chad Mirkin Professor of chemistry, Northwestern University
Nicholas Negroponte Professor of media technology and founding chairman, MIT Media Laboratory
*Micah Siegel President and CEO, Concept2Company
Michael S. Tomczyk Managing director, Mack Center for Technological Innovation, Wharton School, University of Pennsylvania
Sophie V. Vandebroek Chief engineer, Xerox
*Susie Wee Principal research scientist
and R&D department manager, Hewlett-Packard Labs
Chelsea C. White III Professor of transportation and logistics, School of Industrial and Systems Engineering, Georgia Institute of Technology
Jackie Ying Executive director, Institute
of Bioengineering and Nanotechnology, Singapore
*Daphne Zohar Founder and managing general partner, PureTech Ventures

*Past TR100 young innovator honoree

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