Funding for this research was provided by:
grants from National Natural Science Foundation of China (Grant No. 81400672)
The Health and Family Planning Commission of Zhejiang Province (2016ZDA006)
Article History
Received: 24 March 2017
Accepted: 26 March 2018
First Online: 10 April 2018
Ethics approval and consent to participate
: This study was approved by the Ethical Committee of Zhejiang University (Hangzhou, People’s Republic of China) (Ref: 2013–662). Each patient read and signed a consent form before enrolment in the study.
: All authors consent to publish the manuscript.
: The authors have indicated that they have no conflicts of interest regarding the content of this article.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.