News Release

1. Learning with robots

Here today, gone tomorrow. Sometimes.

That's one of the conclusions Reza Shadmehr, Johns Hopkins University assistant professor of biomedical engineering, has made from his study of how the human brain learns new motor skills. The key to his research is a portable, multi-joint robot arm that physically interacts with the human arm.

In one of his experiments, Dr. Shadmehr uses the arm to teach human subjects a new task, such as moving a milk bottle in a particular manner. He has found that a subject can rather quickly learn to move his or her arm in synch with the programmed robot. However, all memory of the task is lost the next day if another new motor task is learned soon after the first.

"But if I increase the time between teaching the two tasks, you no longer have the problem of vulnerability of memory," said Dr. Shadmehr. "You can be tested on either task, and performance shows you will recall them."

Dr. Shadmehr, a recent recipient of an Office of Naval Research Program grant for his innovative research, believes that understanding the role of various brain structures in forming motor memories will lead to some practical applications, like using robots to create virtual training environments.

"One can imagine training a subject -- using "mechanical feelings" -- to perform a task that otherwise cannot be trained, because it is too dangerous or occurs too infrequently," Dr. Shadmehr said. He gave as examples learning to defuse a bomb or perform specialized surgery that is only seen in wartime.

2. Making movies - of the heart

Finding non-invasive methods of detecting current or potential heart defects is the goal of a team of Johns Hopkins researchers, including an engineer specializing in the field of three-dimensional image processing.

Jerry Prince, an associate professor of electrical and computer engineering, is developing a computerized system that uses magnetic resonance imaging to measure cardiac motion. His system produces 3-D "movies" of a beating heart as it moves through a complete beat cycle, and -- when perfected -- will enable physicians to identify damaged areas long before they can be diagnosed by other techniques.

"Early scans took 20 minutes, and you used many cardiac cycles to image different pieces of the heart. Accordingly, the image processing was difficult," said Dr. Prince, who is collaborating with faculty from the Johns Hopkins School of Medicine as well as School of Engineering colleagues. "Now, we can scan the heart in one or a few breath holds, on the order of 30 seconds to a minute. We're making significant progress."

While medical imaging is one of the most visible examples of three-dimensional image processing and reconstruction, Dr. Prince said other applications he is pursuing include brain mapping, nondestructive evaluation of materials, synthetic aperture radar and geophysical imaging.

Note: Videotape of the 3-D movies of a beating heart is available.

3. New ways to beat the heat

Computers of the future may use liquid - and not air - to stay cool.

Cila Herman, assistant professor of mechanical engineering, is conducting a number of heat transfer and fluid mechanics experiments that could also one day revolutionize the electronics, refrigeration, air conditioning, chemical and hydrocarbon industries.

One of her experiments focuses on liquid cooling, a complex system that involves the direct submersion of a computer unit into a liquid to prevent heat-related damage. Another, in collaboration with mechanical engineering colleagues Andrea Prosperetti and Omar Knio, is research into the development of thermoacoustic refrigerators. These are devices that do not require refrigerants and are environmentally safer than conventional refrigerators.

Dr. Herman, one of only about a dozen women in the United States to work in academic heat transfer research, presented her findings on heat transfer enhancement in electronic system models at the NATO Advanced Study Institute on the Cooling of Electronic Systems in Cesme, Turkey.