1. Department of Textile Engineering, Chungnam National University, Daejeon 305-764, South Korea, Department of Oral Biochemistry and Craniomaxillofacial Reconstructive Science, Dental Research Institute, and BK21 HLS, Seoul National University College of Dentistry, Seoul 110-749, South Korea, and College of Pharmacy, Ewha Wowans University, Seoul 120-750, South Korea