Tei, S
Becker, C
Kawada, R
Fujino, J
Jankowski, K F
Sugihara, G
Murai, T
Takahashi, H
Article History
Received: 7 January 2014
Revised: 24 March 2014
Accepted: 16 April 2014
First Online: 3 June 2014
Competing interests
: The authors declare no conflict of interest.