1. Research Institute for Environmental Management Technology, National Institute
of Advanced Industrial Science and Technology (AIST), Onogawa 16-1,
Tsukuba, Ibaraki 305-8569, Japan
2. Research Center for Stem Cell Engineering, National Institute of Advanced
Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba,
Ibaraki 305-8562, Japan