Author contributions
Conception and design of study: Mi Zhou and Qingfeng Li; Acquisition of data: Mi Zhou, Jing Zhong, Lei Bi, Pengcheng Shang, Yan Xing, Bo Wang, Jianlan He, Ying Xu, Tao Luo, Maohua Ma; Data analysis and/or interpretation: Mi Zhou, Jing Zhong and Lei Bi; Drafting of manuscript: Mi Zhou and Qingfeng Li.
Disclosure statement
No potential conflict of interest was reported by the author(s).