1. Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
2. Department of Food Science, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
3. Present address: Department of Physics, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates.
4. Corresponding author. E-mail: scanlon@cc.umanitoba.ca