Hu, Yun
Sun, Qinwei
Liu, Jie
Jia, Yimin
Cai, Demin
Idriss, Abdulrahman A.
Omer, Nagmeldin A.
Zhao, Ruqian
Article History
Received: 23 August 2016
Accepted: 5 December 2016
First Online: 6 January 2017
Competing interests
: The authors declare no competing financial interests.