About the Authors
National Institute on Aging, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland, United States of America
Florida State University College of Medicine, Tallahassee, Florida, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: AT JAS ARS WC EMS LF. Performed the experiments: JAS. Analyzed the data: AT JAS ARS. Wrote the paper: AT.