Funding for this research was provided by:
National Natural Science Foundation of China (31800938)
Natural Science Foundation of Guangdong Province (2018A030313406)
MOE (Ministry of Education in China) Project of Humanities and Social Sciences (17YJCZH040)
Guangzhou University's training program for excellent new-recruited doctors (YB201707)
First Online: 7 February 2020
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.