Funding for this research was provided by:
Department of Education of Liaoning Province (LZ2015036)
National Natural Science Foundation of China (21575019)
Article History
Received: 8 December 2017
Revised: 5 February 2018
Accepted: 14 February 2018
First Online: 19 March 2018
Compliance with ethical standards
: The saliva samples involved in this work were obtained from voluntary participants with informed consent. This study was carried out in accordance with the ethical principles for medical research involving human subjects as described by the World Medical Association.
: The authors declare that they have no conflict of interest.