Emeritus Professor of Chemistry
Adjunct Professor of Bioengineering
Ph.D. University of Washington, 1970
Professor Callis is an instrumentation scientist whose research expertise is in the domain of molecular spectroscopy. He and his students develop new types of spectroscopic instruments for answering diverse analytical questions. He searches for important scientific problems where progress is being limited by the measurement tools currently available. Wherever possible he works closely with researchers who are expert in the problem and can provide guidance in the development of a new instrument.
Particularly intriguing are the opportunities afforded by a new generation of imaging sensors which permit spectroscopy to be combined with imaging for the non-destructive localization of analytes in space. For example, in collaboration with Professor Rick Gustafson (Forestry), we have recently developed a flow-through fiber analyzer for on-line monitoring and control of pulping operations. This unique instrument provides morphological and chemical information on individual wood fibers at high rates of speed. Central to this instrument is a novel flow cell that hydrodynamically focuses the fibers into the focal plane of a fluorescence epi-illumination microscope. Flash illumination freezes the particles’ motion, and the resultant fluorescence images are captured by gated CCD cameras.
Luminescent barometry is an optical technique that provides a method for continuous pressure mapping of aerodynamic surfaces. It is based on the use of a luminescent paint which consists of a phosphorescent compound, a platinum porphyrin, dissolved in an oxygen permeable polymer. When the surface to be studied is coated with the paint and illuminated with ultraviolet light, it is observed to give a beautiful red luminescence whose intensity is found to be proportional to the inverse of the oxygen pressure at the surface. This technique is currently being applied to the challenging problem of insect flight in collaboration with Professor Daniels (Zoology) and Professor Wettlaufer (Applied Physics).
Thus, students have a unique opportunity to participate in interdisciplinary research. Collaboration with other scientists with complementary skills and viewpoints can be a stimulating and rewarding experience. In addition, this interdisciplinary team approach provides students with a broad view of how research is conducted in industry and national laboratories, yet offers rigorous training in instrumentation science based upon the guiding principles of the theory of systems.
“In vivo fluorescence imaging for detection of damage to leaves by fungal phytotoxins.”, W.J. Bower, L. Ning, L.S. Daley, G. A. Strobel, G. E. Edwards, and J. B. Callis, Spectroscopy, 13 36 (1998).
“Five novel applications of imaging visible and short near-infrared spectrophotometry and fluorometry in the plant sciences - Part II: Non-invasive in vivo applications.”, L. Ning, A. M. Chozinski, A. Azarenko, L. S. Daley, W. J. Bowyer, T. Buban, G. E. Edwards, J. B. Callis, and G. A. Sobel, Spectroscopy, 12 37 (1997).
“Quantification of hydrofluoric acid species by chemical-modeling regression of near-infrared spectra.”, C. J. Thompson, J. D. S. Danielson, and J. B. Callis, Anal. Chem., 69 25 (1997).
“Recovery of digital information stored in living plant leaf photosynthetic apparatus as fluorescence signals.”, L. Ning, B. E. Petersen, G. E. Edwards, L. S. Daley, and J. B. Callis, Appl. Spectrosc., 51 1 (1997).
“Spectroscopic imaging of water in living plant leaves - Part II: Challenges, uses and advantages of in vivo absorbance methods for the analysis of biological material.”, L. Ning, L. S. Daley, W. J. Bowyer, E. H. Piepmeier, G. A. Strobel and J. B. Callis, Spectroscopy, 11 68 (1996).
John Simon Guggenheim Memorial Foundation Fellow