Guo, Xiao-gang
Ding, Jie
Xu, Hui
Xuan, Tian-ming
Jin, Wei-quan
Yin, Xiang
Shang, Yun-peng
Zhang, Fu-rong
Zhu, Jian-hua
Zheng, Liang-rong
Article History
Received: 22 April 2014
Accepted: 15 September 2014
First Online: 30 September 2014
Competing interests
: The authors declare no competing financial interests.