About the Authors

Sandra Zetina

Affiliation Instituto de Investigaciones Estéticas, Universidad Nacional Autónoma de México, México D.F. 04510, México

Francisco A. Godínez

Affiliation Instituto de Ingeniería, Universidad Nacional Autónoma de México, México D.F. 04510, México

Roberto Zenit

zenit@unam.mx

Affiliation Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510, México

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: SZ RZ. Performed the experiments: SZ RZ. Analyzed the data: FG RZ. Contributed reagents/materials/analysis tools: RZ. Wrote the paper: SZ FG RZ.