1. Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
2. Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, United States
3. Department of Arts and Sciences, Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan