Zhang, Zhang
Yang, Ruoyan
Gao, Yanshan
Zhao, Yufei
Wang, Junyang
Huang, Liang
Guo, Jiang
Zhou, Tuantuan
Lu, Peng
Guo, Zhanhu
Wang, Qiang
Article History
Received: 25 July 2014
Accepted: 7 October 2014
First Online: 28 October 2014
Competing interests
: The authors declare no competing financial interests.