1. Unit on Membrane Chemical Physics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
2. Postdoctoral Research Associate Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
3. Department of Physics and Astronomy, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
4. Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States