1. Division of Nursing, Yamaguchi University Hospital, Ube 755-0046, Japan
2. Division of Nursing, Yamaguchi-ken Saiseikai Shimonoseki General Hospital, Shimonoseki 759-6603, Japan
3. Former Student of Department of Nursing, Faculty of Health Sciences, School of Medicine, Yamaguchi University, Ube 755- 8505, Japan
4. School of Health Sciences, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan