1. Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278‐8510, Japan, http://www.rs.noda.tus.ac.jp/aokilab/
2. Bruker Biospin K. K., 3‐9 Kanagawa‐ku Moriya‐cho, Yokohama, 221‐0022, Japan
3. Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, 2‐1 Hirosawa, Wako, Saitama 351‐0198, Japan
4. Research Institute for Biomedical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278‐8510, Japan
5. Imaging Frontier Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda 278‐8510, Japan