1. Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
2. Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
3. Center for Functional Nanomaterials, Brookhaven National Laboratory, 735 Brookhaven Avenue, Upton, New York 11973, United States
4. Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California, San Francisco, California 94143, United States