1. Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan, China
2. The University of Hong Kong, Division of Spine Surgery, Department of Orthopaedics and Traumatology, Pokfulam, China, Hong Kong
3. City University of Hong Kong, Department of Physics & Materials Science, Kowloon, China, Hong Kong, Tat Chee Aenue