1. The Department of Surgery and Children's Center for Fetal Research Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
2. The Department of Pediatric Surgery Osaka University graduate School of Medicine Osaka Japan
3. Department of Biomaterials Field of Tissue Engineering, Institute for Frontier Medical Sciences, Kyoto University Kyoto Japan
4. Department of Ma rial Processing Graduate School of Engineering, Tohoku University Sendai Japan
5. Department of Material Chemistry Graduate School of Engineering, Kyoto University Kyoto Japan