1. School of Public Health, Xi’an Jiaotong University, Health Science Center, Xi’an, Shaanxi, PR China
2. Shenzhen Institute, Xi’an Jiaotong University, Shenzhen, Guangzhou, PR China
3. Collage of Health Science, Salale University, Fitche, Ethiopia
4. Department of Odontolgy, Umea University, Umea, Sweden