Science / Technology - Colloquium
Thursday, April 10, 2008
4:00 PM-5:00 PM
Olin Hall
107
I describe three experimental techniques, resonant ultrasound spectroscopy (RUS), relaxation calorimetry (RC), and dielectric relaxation spectroscopy (DRS). All are used extensively in condensed matter physics, and also are successfully applied to biological systems, proteins and DNA. These techniques have a common theme-they all probe normal modes of vibration. RUS probes mechanical oscillator strength (phonons), DRS probes the low-frequency sum of all the infrared-active oscillator strengths, and RHC probes entropy from all types of vibrational modes.
RUS measures the mechanical resonances of a material to determine all elastic constants at once. Its accuracy and high sensitivity can be useful in investigating the hydration and dehydration of protein crystals. The RC that we developed at LANL improves accuracy and reduces noise by eliminating digitization artifacts present in all commercial calorimeters. Originally developed for high temperature superconductors, we describe here its application to DNA melting. DRS, another popular condensed matter technique, measures the dielectric response of a system and is sensitive to the dynamics and hydration properties of proteins. We recently studied protein-solvent interactions of horse myoglobin (Mb) in glycerol/H2O mixtures with DRS from 40Hz-110MHz and showed that the Myoglobin (Mb)-related process is associated with the conformational uctuations of the whole Mb protein.
Cost: FREE
Sponsored by: WPI Physics Department, Dr. Stephan Koehler
Suggested Audiences: College
E-mail:
sak@wpi.edu
Phone: 508-831-5090
Last Modified: April 3, 2008 at 8:35 AM
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