Funding for this research was provided by:
National Natural Science Foundation of China (81461130016)
Beijing Municipal Natural Science Foundation (7151005)
Text and Data Mining valid from 2019-04-09
Received: 1 August 2017
Revised: 4 March 2019
Accepted: 2 April 2019
First Online: 9 April 2019
Compliance with ethical standards
: The authors declare that they have no competing interests and consent for publication is available.
: The study was approved by the ethics committee of Beijing Huilongguan Hospital. After a complete description of the study to all participants, the written informed consent was obtained.
: All data are fully available without restriction.