Fan, P
Zhang, Y
Liu, L
Zhao, Z
Yin, Y
Xiao, X
Bauer, N
Gladkich, J
Mattern, J
Gao, C
Schemmer, P
Gross, W
Herr, I
Article History
Received: 19 January 2016
Revised: 8 May 2016
Accepted: 10 May 2016
First Online: 2 June 2016
Competing interests
: The authors declare no conflict of interest.