About the Authors

Cecilia Young

ceciliatyp@yahoo.com.hk

Affiliation Private Practice, Hong Kong

Kin Yau Wong

Affiliation Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America

Lim K. Cheung

Affiliation The University of Hong Kong, Hong Kong

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: CY KYW LKC. Performed the experiments: CY. Analyzed the data: CY KYW LKC. Contributed reagents/materials/analysis tools: CY KYW. Contributed to the writing of the manuscript: CY KYW LKC. Wrote the paper: CY KYW LKC.