About the Authors

Shuo Wang

Affiliation Center for Occupational and Environmental Health, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America

Robert C. Spear

spear@berkeley.edu

Affiliation Center for Occupational and Environmental Health, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: SW RCS. Performed the experiments: SW. Analyzed the data: SW RCS. Wrote the paper: SW RCS.