摘要
The abstract should be structured into the subsections ＂BACKGROUND＂, ＂OBJECTIVE＂, ＂DESIGN, TIME AND SE-FFING＂, ＂PARTICIPANTS/MATERIALS＂, ＂INTERVENTIONS/METHODS＂, ＂MAIN OUTCOME MEASURE（S）＂, ＂RESULTS＂. and ＂CONCLUSION＂.
The abstract should be structured into the subsections ＂BACKGROUND＂, ＂OBJECTIVE＂, ＂DESIGN, TIME AND SE-FFING＂, ＂PARTICIPANTS/MATERIALS＂, ＂INTERVENTIONS/METHODS＂, ＂MAIN OUTCOME MEASURE（S）＂, ＂RESULTS＂. and ＂CONCLUSION＂.
