1. Department of Cardiovascular Surgery, Tianjin Chest Hospital, Tianjin 300051, P. R. China
2. Tianjin Medical University, Tianjin 300203, P. R. China
3. Department of Materials Engineering, North China Institute of Aerospace Engineering, Langfang 065000, P. R. China
4. Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China