1. Pharmaceutical Sciences Department, North Dakota State University, Fargo, North Dakota 58105, United States
2. Fred & Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
3. Coatings and Polymeric Materials Department, North Dakota State University, Fargo, North Dakota 58108, United States
4. Physics Department, North Dakota State University, Fargo, North Dakota 58105, United States
5. Department of Biological Sciences, North Dakota State University, Fargo, North Dakota 58102, United States