Contributors
All authors discussed and commented the results on the manuscript. Ming-Kang Zhong and Ming-Ming Yan designed the study; Ming-Ming Yan, Jing Li and Nang Lu performed the study; Jing Li and Nang Lu contributed production of form and analytic tools; Xiao-Yan Qiu and Shu-Shan Wu analyzed and interpreted of data; Ming-Ming Yan and Shu-Shan Wu drafted the manuscript; Xiao-Yan Qiu and Ming-Ming Yan revised the manuscript; Ming-Kang Zhong and Ming-Ming Yan final approved of the version to be published.