eng Science and Education Publishing American Journal of Public Health Research 2327-6703 2014-09-21 2 5A 0 0 10.12691/ajphr-2-5A-0 AJPHR201425A0 article Foreword for Special Issue Ningning Zhao http://pubs.sciepub.com/ajphr/2/5A/0/ajphr-2-5A-0.pdf