Declaration 

The corresponding author must declare in the cover letter that the manuscript has not submitted to any journal for possible publication, or has not published elsewhere (in part or full). If we notice such kind of malpractice, the author(s) will be blacklisted for our journal, and no article from those authors will be processed in future. Besides, the list of authors may be forwarded to the editors of other related journals around the world. See the COPE guidelines.