Ohkuma, T
Hirakawa, Y
Nakamura, U
Kiyohara, Y
Kitazono, T
Ninomiya, T
Article History
Received: 22 January 2015
Revised: 13 May 2015
Accepted: 17 May 2015
First Online: 25 May 2015
Competing interests
: The authors declare no conflict of interest.