1. Department of Mechanical and Aerospace Engineering, Center for Surface Science and Plasma Technology, University of Missouri, Columbia, MO, USA
2. Department of Pediatric Dentistry and Community Oral Health, College of Dentistry, The University of Tennessee Health Science Center, Memphis, TN, USA
3. Center for Research on Interfacial Structure and Properties, School of Dentistry, University of Missouri–Kansas City, Kansas City, MO, USA