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