About the Authors

Weiwei Zhang

Affiliation Department of Anatomy, Shandong University School of Medicine, Jinan, China

Zhenzhong Li

zli@sdu.edu.cn

Affiliation Department of Anatomy, Shandong University School of Medicine, Jinan, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: ZL. Performed the experiments: WZ. Analyzed the data: WZ. Wrote the paper: ZL WZ.