Nobel Prizes Go to Scientists Harnessing Odd Phenomena: Superconductivity, Superfluidity, Imaging with Magnetism, and Membrane Chemistry

Article excerpt

The 2003 Nobel prizes in the sciences were announced early this week.

Physiology or Medicine

Two scientists will share this year's Nobel Prize in Physiology or Medicine for their groundbreaking work in producing images of internal organs by inducing live tissues to emit tiny radio signals.

In this technology, called magnetic resonance imaging (MRI), a technician exposes a portion of a patient's body to a strong magnetic field. Like compass needles swiveling north, protons in the tissue's atoms align with the applied magnetic field. Then, the technician directs a radio pulse at the tissue, scrambling the positions of the protons. When the pulse ends, the protons revert to their original positions, emitting measurable radio signals.

Scientists discovered the phenomenon of magnetic resonance (MR) in the 1940s and used it initially for determining chemical structures. Then, in the 1970s, Paul C. Lauterbur, a chemist at the State University of New York in Stony Brook, added a second set of magnets to an MR device. This development led to instruments capable of generating images. Lauterbur, who is now at the University of Illinois at Urbana-Champaign, finessed the technique so that it could yield more-detailed, two-dimensional images that portrayed differences between tissue that have varying water concentrations. The work has earned him a share of the prize.

The other Nobel winner, Peter Mansfield of the University of Nottingham in England, expended on Lauterbur's findings by developing mathematical techniques for capturing, analyzing, and processing MR signals more efficiently. His work has made possible three-dimensional renderings of internal organs.

It helps that water makes up two-thirds of the human body. Water is readily identifiable in MRI because the protons in each molecule's two hydrogen atoms give off radio waves in a recognizable frequency. By detecting this signature and generating images from it, MRI allows a physician to distinguish between fluids and soft tissues such as brain and muscle, neither of which shows up clearly on X rays. In 2002, doctors prescribed roughly 60 million MRIs.

"I'm thrilled that this work has finally been recognized," says Peggy Fritzsche, a radiologist at Loma Linda University School of Medicine in California and president of the Society of North America. The award, she says, is long overdue.

A typical MRI machine is roughly the size of an office cubicle and has along tube through its middle. A patient lies in this tube, surrounded by the powerful magnet at the heart of the machine. MRI images can reveal injuries, cancer, brain damage, and other tissue abnormalities. The technology differs from X rays and computed tomography, technologies for which scientists won Nobel prizes in 1901 and 1979, respectively. While those devices use ionizing radiation to create images of internal tissues, MRI relies on apparently harmless radio waves and magnets.

"This is a wonderful example of how basic research on atoms and molecules led to an important clinical application [that has] revolutionized the practice of medicine," says Elias A. Zerhouni, director of the National Institutes of Health. MRI "improves diagnosis and reduces the need for surgery and other invasive procedures," he says.--N. SEPPA

Physics

For their theoretical insights regarding some of the strangest behaviors ever observed in metals and fluids, three physicists have won this year's Nobel Prize in Physics.

Vitaly L. Ginzburg of the P.N. Lebedev Physical Institute in Moscow and Alexei A. Abrikosov, now at Argonne National Laboratory in Illinois, were selected for their theories about superconductors--materials that shed all electrical resistance when chilled to extremely cold temperatures (SN: 11/30/02, p. …