Author contributions
Ju Hee Kim, Seung Won Lee, Hey Sung Baek and Man Young Han contributed
to conception and design; Seung Won Lee, Dong Gun Yeon, Hye Mi Jee and
Man Young Han acquired the data; Man Young Han, Ju Hee Kim, Seung Won
Lee, Eun Kyo Ha, Youn Ho Shin, Seoung In Seo, Sun Hee Choi, Myungsoon
Seong analyzed and interpreted the data; Ju Hee Kim and Seung Won Lee
drafted the article; Dong Keon Yon, Seung Won Lee, Jung Won Yoon, Hyun
Jung Shim and Youn Ho Shin critically revised the article and provided
important intellectual content; and all authors approved the final
version to be published.