Declaration of interests
The authors have no conflicts of interests to disclose.
Contribution
to authorship
Lingying Wu and Kun Song: Study design; Yana Ma, Ning Li and Hualei Bu:
Wrote and edited the article; Chengjuan Jin: Assisted in editing the
article; Yongwen Huang, Chengjuan Jin, Hao Wen, Shuai Feng, Hui Zhang,
Beihua Kong: Provision of resources. All authors had full access to all
the data in the study and had final responsibility for the decision to
submit for publication.