Funding for this research was provided by:
Khon Kaen University (NA)
Thailand Research Fund (RTA 5680006, MRG 5980002)
Received: 27 April 2017
Accepted: 21 January 2018
First Online: 30 January 2018
Ethics approval and consent to participate
: Written ethical consents were received from participants. The study was approved by Institutional Human Ethics Committee of Khon Kaen University (HE571489).
: Not applicable.
: The authors declare that they have no competing interests.
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