Top row: Walter Chazin, Raymond DuBois; bottom row: Leonard Feldman, Dennis Hall

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NASHVILLE, Tenn. ñ Four Vanderbilt scientists ñ Walter J. Chazin, Raymond N. Dubois Jr., Leonard C. Feldman and Dennis G. Hall ñ have been elected as fellows of the American Association for the Advancement of Science (AAAS), an honor bestowed upon them by their peers. They are being honored for contributions to research that runs the gamut from determining the atomic structure of proteins to paving the way for improved treatments of digestive diseases including colon cancer, from investigating the atomic structure of materials to providing new insights into the fundamental nature of light.

They are among 308 scientists from around the country who have been elevated to this rank because of their efforts to advance science or its applications that are deemed scientifically or socially distinguished. New fellows will be presented with an official certificate and a gold and blue rosette pin on Saturday, Feb. 19, at the 2005 AAAS Annual Meeting in Washington, DC.

Chazin was cited for "his important contributions to the chemistry and structural biology of proteins." He is the director of the Center for Structural Biology and Chancellor's Professor of Biochemistry and Physics. A nuclear magnetic resonance (NMR) spectrography expert, he was recruited in 1999 to build Vanderbilt's NMR presence in the context of a more comprehensive structural biology center. The center is now used by researchers across campus to determine the structure of biological molecules at atomic resolution.

The Chazin laboratory has made significant progress in working out the underlying basis for the concerted action of multiple proteins that gather together to read the information in human genomes and help maintain their accuracy. He and his colleagues are applying the basic approach that they developed for this purpose to study defects in proteins that lead to specific cancers, cardiac arrhythmias and diabetes-induced atherosclerosis.

In addition to serving as director-at-large of Vanderbilt's NMR centers, Chazin is an Ingram Professor of Cancer Research and director of the Molecular Biophysics Training Program. He came to Vanderbilt from the Scripps Research Institute at the University of California, San Diego.

DuBois was cited for "outstanding contributions to the field of cancer protection and digestive disease research and for the discovery of the role of the cyclooxygenase-2 enzyme in colorectal carcinogenesis." DuBois ñ Mina Cobb Wallace Professor of Gastroenterology and Cancer Prevention; professor of medicine; professor of cancer biology and director of the Division of Gastroenterology ñ is recognized internationally for his groundbreaking contributions toward understanding the role of cyclooxygenase-2 (COX-2) in cancer and the potential for COX-2 inhibition in preventing and treating cancers.

The COX enzymes generate prostaglandins, ubiquitous molecules that are involved in a host of physiological processes, including pain and inflammation. DuBois' lab was the first in the world to report that COX-2 expression is elevated in human colorectal cancers, and inhibitors of the enzyme blocked the growth of colorectal cancer cells that express COX-2. In 2000, an international team of researchers, including DuBois, reported that the use of Celebrex ñ the first selective COX-2 inhibitor ñ led to a significant reduction in the number of polyps in patients with familial adenomatous polyposis, an inherited condition characterized by multiple colon polyps that usually become malignant. The landmark finding, published in The New England Journal of Medicine, opened the floodgates for studies aimed at preventing other cancers by blocking production of prostaglandins.

DuBois and his colleagues continue to pursue the precise mechanisms by which COX-2-derived prostaglandins promote tumor development in the colon. The ultimate hope is to identify other targets for drugs that may be even more effective at interfering with this process.

Feldman was cited for his "innovative contributions to the use of ion scattering as a tool for materials analysis and for the understanding of the structure of interfaces." Before moving to Vanderbilt in 1996, Feldman spent 29 years as a researcher and department head at Bell Laboratories under AT&T and Lucent Technologies management.

Throughout his career, Feldman has specialized in applying techniques from nuclear physics to study the structure of materials and the nature of the interfaces that form between different materials. Much of his work has involved the study of the interface between silicon and silicon dioxide, which has been called the "heart of the semiconductor revolution" because of its crucial role in the architecture of computer chips and other solid state electronic devices.

He holds 20 patents and has authored some 350 publications and co-authored three books on materials physics. His most important patent involves the use of nitrogen gas in the manufacture of silicon/silicon dioxide devices. A typical integrated circuit has an insulating layer of silicon dioxide separating its silicon and metal layers. The presence of nitrogen gas keeps the metal layer from poisoning the silicon as the oxide layer is made thinner and thinner. This procedure has become a standard practice in the semiconductor industry and has allowed manufacturers to continue shrinking the size of microelectronic devices.

Since joining Vanderbilt as Stevenson Professor of Physics, Feldman has taken on the job of directing both the Vanderbilt Institute of Nanoscale Science and Engineering ñ the university's interdisciplinary research program in nanoscience and nanotechnology ñ and a national nanoscience education program. In 2003, he received a co-appointment as professor of materials science and engineering in the Vanderbilt School of Engineering. He also holds positions as a distinguished visiting scientist at Oak Ridge National Labs and adjunct professor of physics at Fisk University. In 1999, Feldman won the David Adler Award of the American Physical Society for his work in materials physics.

Hall was cited for "contributions to the understanding of optical phenomena in solid-state structures, particularly those involving waveguides." He presently serves as associate provost for research and graduate education, professor of physics and professor of electrical engineering at Vanderbilt. Until he came to Nashville in 2000, Hall directed The Institute of Optics at the University of Rochester. Throughout the 1980s and 1990s, he and his students carried out a program of theoretical and experimental investigations of the optical effects associated with confined systems: systems that change the way that light travels or is emitted, absorbed or detected. The most familiar confined system in widespread use today is the optical fiber that confines light within a microscopically thin strand of glass.

There are a large number of possible confined systems that can be investigated in the pursuit of deeper understanding of the nature of light. As recorded in the pages of more than 100 research articles and the 21 doctoral dissertations and six master's theses that he supervised, Hall and his students explored many such systems. As a consequence, they discovered or demonstrated a number of subtle or unexpected optical effects, fabricated unusual confinement structures, and made a variety of first-ever measurements.

In 1992, Hall's research team gained international attention for designing and building an unusual surface-emitting semiconductor laser based on a novel two-dimensional structure. By pushing the limits of the technology used to create such devices, the researchers successfully constructed a laser that forced light waves to travel as two-dimensional circular waves, mimicking the way that water waves travel when a stone is dropped into a pond. Another, more recent set of experiments used a layer of light-emitting organic molecules to demonstrate that under the right conditions, light can shine through a layer of metal that is normally opaque.

Media contact: David F. Salisbury, (615) 343-6803
David.salisbury@vanderbilt.edu