1. Laboratory of Wood Chemistry, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
2. Wood Chemistry Laboratory, Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba-shi, Ibaraki 305-8687, Japan