Mitigating Impact of Stroke

Some 700,000 individuals suffer strokes in the U.S. each year, and a hefty percentage of those wind up with problems in walking. To help such victims, a team from MIT has developed a rehabilitation robot that lets walking-impaired individuals make faster progress toward getting moving again. Like MIT-Manus, an earlier robot for the arms, the new device is meant to both assist and strengthen a victim’s lower extremities. According to Hermano Igo Krebs, an MIT principal research scientist and one of the inventors of the device, “Anklebot” might do the same as the upper-extremity robot did promoting a faster and better recovery as patients strive to relearn walking skills. Krebs and the director of the lab where he works, Neville Hogan, a professor of mechanical engineering, have joined clinicians at the Baltimore V.A. Medical Center to carry out an initial trial of Anklebot.

Seeing Collaboratively

An enduring mystery of the brain is how it meets challenges like “finding Waldo” — that is, focusing on a specific target, like the famed cartoon character with the red-andwhite stocking cap, when the figure’s in a chaotic or very complicated scene. It turns out, says a leading researcher from the McGovern Institute for Brain Research at MIT, that select brain cells may in effect band together to accomplish tasks like this. Robert Desimone, director of the institute and a professor of brain and cognitive sciences at MIT, notes that part of the story is the activity of brain cells specialized for a specific type of sensory signal — say, in this case, the color red. Those cells, primed by the thought of a hunt for Waldo, would already be more active than usual when the search was launched. But added to the effects of these relatively few cells would be that of others that are activated by different aspects of Waldo’s image — for example, its shape. Through a mechanism the researchers are still working out, many of the activated cells seem to act in concert to ensure that the brain avoids focusing on anything else in order to target — in this case — Waldo. “We think it’s not just a question of a few individual neurons,” says Desimone. “It’s how those neurons becomes synchronized with others to make their voices heard.” Scientists from the National Institutes of Health were also involved in this study.

Cheaper Calling

Though wireless communications technologies have been spreading fast, the cell base stations that make cell-phoning possible have a problem: the amplifiers they use in connecting with phones and similar devices are expensive, inefficient, bulky, and require massive battery backups. Amplifiers in general are created using either an older vacuum electron device (VED) technology or a solidstate technology. Though both offer comparable performance, the wireless industry has chosen to go the solid-state route. A recent innovation at MIT, though, could drastically alter that picture, in the process paring wireless costs by billions of dollars. A key point about conventional VED-based amplifiers, says MIT Principal Research Scientist and Group Leader Chiping Chen of the MIT Plasma Science and Fusion Center, is that they rely on pencil-like electron beams — in other words, beams that are slender and round. Using a modern variant of last century’s VED technology, the MIT group has now developed what they call a “ribbon electron beam.” If you could cut this form of beam cross-wise, the shape you’d see would be an ellipse. “This technology,” Chen adds, “could change how radio-frequency amplifiers are made.” Notably, it would substantially increase the amplifiers’ efficiency, in the process letting manufacturers sharply reduce the size and cost of these devices. That in turn could allow wireless companies to mount amplifiers in cell towers rather than making them part of large, and expensive, separate installations.

Clues to Cancer

Adult stem cells, the self-renewing cells thought to exist in many parts of our bodies that give rise to more specialized cells, may soon find a role as an early warning sign for lung cancer. Researchers at the MIT Center for Cancer Research, with colleagues elsewhere, did rodent studies of the most common type of lung cancer, lung adenocarcinoma. The appearance of this variant of the disease followed a jump in the numbers of a kind of stem cell that is found deep within the lungs. This type of cell appears to be rare in normal lungs. The cells do appear to proliferate prior to the growth of tumors, though, opening up the possibility — assuming the same thing happens in humans — of using the stem cells as early warning signs for cancer. “This work has identified a new population of cells that links the normal biology of the lung to lung cancer development,” says Tyler Jacks, cancer center director and professor of biology. Carla F. Kim, a postdoctoral fellow in Jacks’ lab and lead investigator for the study, says the lung stem cells “may be the first to respond to the genetic defect that, in this mouse model, later leads to cancer.” Besides the MIT group, researchers from Tufts University and Carleton College participated in the study.