Received: 20 March 2018
Accepted: 26 July 2018
First Online: 7 August 2018
: All of the study population signed written informed consent forms and participation of human subjects did not occur until after informed consent was obtained. All the study procedures and the participants were in accordance with the Declaration of Helsinki (1964) and its later amendments.
: Not applicable.
: The authors declare that they have no competing interests.
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