Funding for this research was provided by:
National Foundation for Science and Technology Development (106-YS.04-2014.40)
Text and Data Mining valid from 2019-03-20
Received: 26 July 2018
Revised: 2 March 2019
Accepted: 5 March 2019
First Online: 20 March 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the Research and Education Committee of Nha Trang University (REC-NTU) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants or their parents as minors (less than 16 years old) included in the study.