1. Advanced
Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720, United States
2. Biological
and Biomimetic Material Laboratory, School of Materials Science and
Engineering, Nanyang Technological University, 637553 Singapore
3. Department
of Physics, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
4. School of Biological Sciences, Nanyang Technological University, 637551 Singapore
5. Departments
of Chemistry, Geoscience, Materials Science Program, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States