title: Comment on "Grain boundary-mediated plasticity in nanocrystalline nickel".
authors.affiliation: Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. mwchen@imr.tohoku.ac.jp
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Yan