Talk Description:
Measurements of conduction in DNA have led to controversial results, some characterizing it as an insulator, some as a metal and still others as a semiconductor. The weight of evidence favors the last. Because DNA is surrounded by water and ions, a charge added to a DNA molecule gives rise to a strong polarization. The charge and the polarization move together as a kind of particle, a polaron, which is strongly scattered by the fluctuations of the water. Conduction in DNA could lead to mutations and carcinogenesis or enable us to use it as electrical wires in tiny circuits.

Biography:
Conwell is widely known for her theoretical studies of the properties of materials. Her early research, with V. F. Weisskopf, on the effect of impurities on the motion of electrons, was an important step for the understanding of conduction in semiconductors, the materials of which transistors are made. That, and additional research, particularly on the effect of a high electric field (“hot electrons”), contributed to better design of transistors and thus to the technologies that led to the computer revolution. She also made significant contributions to theory for conducting polymers, now considered to be highly promising for efficient light sources, and to conduction in DNA.

Conwell was honored by Discover magazine in 2002 as one of “the 50 most important women in science”. In addition to being a member of the National Academy of Sciences, the National Academy of Engineering and the American Academy of Arts and Sciences, she was recently presented a National Medal of Science by President Obama in a White House ceremony.