Author contributions
WM and XZ: conception and design of the research and obtaining financing. WM, LZ, JT, WD, LQ, and XF: acquisition of data. WM, LZ, JT, and XZ: analysis and interpretation of the data. WM, WD, LQ, and XF: statistical analysis. WM: writing of the manuscript. XZ: critical revision of the manuscript for intellectual content. All authors have read and approved the final draft.
