ABSTRACT
BACKGROUND: Skin reproducing membrane is a biomaterial used directly in contact with skin defects, so its toxicity to the body must be taken into consideration. OBJECTIVE: To systematical y evaluate the biocompatibility of skin reproducing membrane of medical fibroin. METHODS: Skin irritation test: the skin defect of New Zealand white rabbit was covered with the skin reproducing membrane of medical fibroin, formaldehyde or normal saline, respectively, and erythema and edema were observed at 24 and 72 hours after treatment. Acute systematic toxicity test: the mice were given extracts of skin reproducing membrane of medical fibroin, phenol and normal saline via tail vein injection; then status of mice, toxicity grade and death were recorded at 24, 48 and 72 hours after injection. Cytotoxicity test: L-929 cel s were co-cultured with 100%, 50%, 25%, 10% skin reproducing membrane of medical fibroin extracts, and absorbance values were detected by ultraviolet spectrophotometry at 2, 4 and 7 days after culture, as wel as by MTT assay after 48 hours of culture, respectively. Besides, L-929 cel s were co-cultured with 100% skin reproducing membrane of medical fibroin extracts, and mRNA expression of fibronectin was determined by qPCR technology after 48-hour culture. RESULTS AND CONCLUSION: Skin reproducing membrane of medical fibroin has no adverse reaction, acute cytotoxicity, skin irritation and systemic toxicity, and additional y, it does not affect mRNA expression of fibronectin. In general, skin reproducing membrane of medical fibroin has good biocompatibility.
ABSTRACT
Objective To investigate the graduate students' mental pressure after the full im-plementation of the charging system and explore effective countermeasures of alleviating the psycho-logical pressure. Methods 413 full-time graduate students of Grade 2014 were randomly selected in a university of Shandong province. The graduate students' psychological pressure scale and self-designed questionnaire survey were used. The data were analyzed using SPSS 17.0 software, statistical descrip-tion of the survey data, independent sample t test, ANOVA. Results ①The psychological pressure of full-time graduate students at their own expense was in themedium pressure level; ②The economic pressure and academic pressure of the male graduate students were higher than those of the female graduate students (P=0.000,P=0.042), the rural economic pressures were greater than urban students graduate students graduate students (P=0.000); Professional graduate economic pressures were greater than academic graduate students (P=0.027);There is difference in the pressure of interpersonal commu-nication among different majors (P=0.016); ③78.75% (315/400) of the graduate students tuition fees, living expenses were mainly from their parents and the national and school awards; ④The percentage of those who completely agreed with the following view: full charge than at public expense is more advantageous to graduate education, comprehensive charge is advantageous to the education career development and comprehensive charge embodies the fairness of education was 84.75% (339/400), 71.25% (285/400) and 68.00% (272/400). Conclusion The full-time graduate students at their own expense have a more rational understanding of the charging policy; economic and academic pressures are the two outstanding pressure sources of the graduate students at the present stage. Graduate should improve their ability to cope with stress, and government and schools should take various measures to help students relieve stress.