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
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
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.