A microscope that can see objects smaller than an atom. The first field test of a fleet of electric vehicles powered by fuel cells. A tariff to limit vehicular traffic in central London. These are but a few of the path-breaking developments that have taken place in recent months in laboratories, corporate suites and the halls of government. For the second year, the SCIENTIFIC AMERICAN 50 recognizes the singular accomplishments of those who have contributed to the advancement of technology in the realms of science, engineering, commerce and public policy. This years selections by the Board of Editors pay tribute to individuals, teams and companies that have stood out in a wide variety of technological disciplines. It also honors Leaders of the Year for achievements in research, business and policy. Their work again demonstrates the ingenuity and resourcefulness that generate the ever more sophisticated tools and solutions for meeting societys needs. --The Editors

Biographies of the three Leaders of the Year follow below. For a complete list of winners, click here. For a full description of their work, visit Scientific American Digital and purchase the December issue.


Roderick MacKinnon
Professor of molecular neurobiology and biophysics, Rockefeller University; investigator, Howard Hughes Medical Institute
Elucidated the structure and function of ion channels, particularly the potassium ion channel.

That electricity might animate mere flesh goes all the way back to Frankenstein, yet the mechanisms remained vague until Roderick MacKinnon, a physician, worked out the structure of the potassium channel. Then, this past spring, he deduced the mechanism by which a potassium channel senses electricity--its voltmeter, as it were. These achievements won him the 2003 Nobel chemistry prize.

When a channel for any one of three inorganic ions--calcium, sodium or potassium--senses a voltage, it opens to allow ions in or out, changing the concentration and thus effecting a behavior, such as neural discharge, muscular contraction or hormone secretion. We could neither think nor move nor survive for many minutes without these channels, and MacKinnon's explanation of them should guide the development of drugs for neuromuscular and other disorders, such as cystic fibrosis and cardiac arrhythmias. Drug companies should show particular interest in the implications for arrhythmia, a common pharmaceutical side effect in numerous patients that has cost them billions in failed clinical trials.

The challenge here, as in the earlier research, lay in forming a crystal of the pore proteins that was good enough to diffract x-rays into patterns a computer could render into images. The task is hard because the proteins are very large and mixed in oils that must be removed with detergent, which is itself a problem. Furthermore, the volt-sensing element has moving parts that are buried deep inside the protein. Interestingly, MacKinnon studied the voltmeter in an Archaebacterium taken from a superhot ocean vent. That an organism so far removed in evolutionary history from us should have such similar channels indicates that the structures were highly resistant to mutation over eons and thus critical to survival.

Toyota Motor Corporation
Toyota City, Japan
Commercialized affordable hybrid cars.

Whereas most other automakers have merely talked of combining internal-combustion engines with electric motors, Toyota has actually been selling such a hybrid car for years. Called the Prius, it came out first in Japan in the late 1990s and soon after in the U.S. Toyota's 2004 Prius, due out in October, appears to get around the dismal engineering trade-offs associated with hybrids by improving performance and fuel economy over last year's model while keeping the price the same, around $20,000.

Hybrid power plants do away with big engines and their extravagance with both fuel and pollution by substituting a small engine, to provide steady power, and an electric motor to assist it during acceleration. The strategy pays off best in stop-and-go city driving (which the Environmental Protection Agency test emphasizes strongly), when a big engine goes almost entirely to waste. Indeed, the Prius actually gets better mileage in the city than on the highway. Unlike the so-called mild hybrids, the Prius does not use the motor solely as an assist but is capable of cruising around on electricity alone.

The new model has been lengthened just enough to move it into the midsize category, giving it more legroom. It also has better acceleration. Yet according to preliminary estimates by the EPA, it now gets 59 miles per gallon in the city and 51 miles per gallon on the highway, up from 52 and 45 mpg, respectively, for the 2003 model. The Prius now goes about twice as far on a gallon of gasoline as the average car in the U.S. fleet; if all vehicles did that well, it would save the U.S. some 1.5 billion barrels of imported oil a year.


Gro Harlem Brundtland
Former secretary general, World Health Organization
Coordinated a rapid global response to stem the SARS outbreaks.

With typical Scandinavian understatement, Gro Harlem Brundtland, then the secretary general of the World Health Organization, worked mainly undercover to meet the challenge of SARS. But she recognized the need to concentrate minds with decisive strokes and did so on three occasions last year. She issued the first global health alert ever, warned about travel to Toronto and other cities, and frankly criticized the Chinese government, which had suppressed news of the outbreak in Guangdong Province.

Quarantines, perhaps helped along by the simple changing of the seasons, contained the outbreak, and that is why the unprecedented toughness is now seen as fully justified. In any case, the old-fashioned containment measures have bought time for the molecular biologists to develop better diagnostic tests and the first vaccines. Furthermore, by setting the precedent of exerting pressure on influential member states (of which there are 192), Brundtland has made life easier for her successors if they should face similar situations. In all these actions, she worked together closely with David Heymann, director of the WHO's office of communicable diseases, and with the Centers for Disease Control and Prevention, whose director, Julie Gerberding, lent critical support. The CDC's Thomas Ksiazek led a team that quickly identified the coronavirus responsible for SARS.

Brundtland, a medical doctor, honed her political talents in a variety of senior governmental jobs in her native Norway before becoming its prime minister, a position she held for three terms. At WHO, she used those skills to raise the organization's profile and to cultivate support in the United Nations. By vigorous fund-raising, particularly among private foundations, she increased the WHO budget by about two thirds, to about $1 billion a year. The money goes to finish old projects, such as the eradication of polio, and the new ones she started, including bringing low-cost drugs to poor countries and improving the surveillance system for emerging diseases, such as SARS. Although Brundtland would very likely have sailed into a second term, she decided to retire, citing her age, which is 64.

For the complete list of winnners of the SCIENTIFIC AMERICAN 50, click here.