Funding for this research was provided by:
Key Project of Hebei North University (120177)
Key Project of Medical Science Research in Hebei Province (20150061)
ORCID
Li-ning SU: http://orcid.org/0000-0001-8118-7601
Content Type
: Correspondence
Copyright
: © Zhejiang University and Springer-Verlag Berlin Heidelberg 2017