Objective:To investigate the feasibility of improving the corrosion resistance of nickel-chromium alloys by the means of cryogenic treatment. Methods:16 disk samples were divided into 4 groups, including control group(C), cryotreat group(E1),tempering after cryotreat group(E2) and simulative porcelain sintering after cryotreat group(E3). All samples were subjected to electrochemical potentiodynamic polarization after immersed in the artificial saliva ISO/TR 10271:1993(E) pH 6.8 for 24 h at ambient temperature. The metallography of all groups were observed by SEM. Results:①Cryogenic treatment elevated the pitting corrosion potential and dropped the corrosion current of Ni-Cr alloys. Following simulative porcelain sintering,as well as tempering after cryotreat, decreased the corrosion current. But the corrosion potential of Ni-Cr alloys fell after cryotreat and following simulative porcelain sintering. Tempering after cryotreat did not affect the pitting corrosion potential. ②Much small secondary substance separated out and evenly distributed along the crystals of Ni-Cr alloys after cryotreat. Conclusion:Cryogenic treatment effectively improves the electrochemical corrosion resistance of Ni-Cr alloys, and tempering following cryotreat is unnecessary. It is not recommended to sintering porcelain after cryogenic treatment.

BACKGROUND:Hair fol icle stem cel s derived from skin and hair have the most readily available sources, and cannot lead to serious complications and immunogenicity after col ection, which can be used for autologous transplantation. OBJECTIVE:To provide effective experiment basis for hair fol icle stem cel s in the repair of skin wound through reviewing the role of hair fol icle stem cel s in promote the repair of skin wound. METHODS:Articles related to hair fol icle stem cel s for the repair of skin wound were retrieved in CNKI and PubMed databases (1999-01/2014-12). The key words were“hair fol icle stem cel , skin repairing, regenerative medicine, tissue engineering”in Chinese and English, respectively. A total of 45 articles based on inclusion criteria and exclusion criteria were obtained for the review. RESULTS AND CONCLUSION:Hair fol icle stem cel s belong to adult stem cel s, which are easy to access, have a significant number, and possess differentiation potential and safety. Hair fol icle stem cel s can promote the repair of skin wound and provides good seed cel s for regenerative medicine and tissue engineering research through early vascularization of the skin, epidermal and appendage regeneration, signaling pathways, and transcription factors.

Objective To explore the application of a three-dimensional simulation system in extended liver resections.Methods A three-dimensional surgical simulation system was used for preoperative assessment and for computer simulation to estimate the resected liver volume,the residual liver volume,and the surgical resection margins.The software virtual liver resection was used to choose the most optimal surgical option.The actual resection,the postoperative liver volume and the actual surgical resection margins were compared.Results 1 patient was diagnosed by ultrasound to develop ascites on post-operative day 2.Another patient was diagnosed by transthoracic ultrasound to have moderate pleural effusion on postoperative day 1.Postoperative liver failure developed in 1 patient.There was no patient who developed bile leakage.The average length of stay was 6 ～ 85 days (average 22 d).There was no recurrence within 1 month after surgery and there was no postoperative deaths.Condusions The three-dimensional surgery simulation system was effective.It gave an accurate evaluation and simulation of the liver surgery.In extended liver resection,it gave good guidance and help.

OBJECTIVE: To analyze the expression of procollagen gene in fracture callus, and to search for the technique of in situ hybridization for undecalcified skeletal tissue. METHODS: In situ hybridization of procollagen gene expression was performed on the undecalcified cryosections of rat fracture callus at 7, 14, and 28 d. RESULTS: The hybridization signals achieved were clear and easy to be localized with high specificity. On the 7th day, the expressions of pro alpha1 (III) in fibroblasts and some chondrocyte-like cells were dominant; and at the end of second week high expression of type-II procollagen mRNA was observed in chondrocytes. At the end of fourth week, the cartilaginous callus was almost all replaced by woven bone tissue, and some type-I procollagen mRNA positive osteoblasts and hypertrophic chondrocytes were found scattering in the woven bone and remnants of cartilaginous callus. CONCLUSIONS: The modified method employed in this study is easier, quicker, and more sensitive with high specificity than the conventional tec hnique for in situ hybridization of procollagen gene expression of decalcified rat fracture callus. The phenomenon of shared phenotype expression, which was demonstrated among cells engaged in fracture healing, indicates an important approach to reveal the mechanism of the origin, differentiation, and orientation of cells.