Scientific Reports 6:454; doi:10.1038/s41598-017-00581-2; Article published online 28 March 2017

In the original version of this Article, Pi-I. D. Lin, and not Ming-Tsang Wu, was listed as the corresponding author. Correspondence and request for materials should be addressed to Prof. Ming-Tsang Wu at e_encourage@yahoo.com. This has now been corrected in the HTML and PDF versions of the Article.