Résumé
Objective:To evaluate the effect of different polishing instruments on the microstructure of composite resin.Methods:Specimens of 5 kinds of resins were randomly divided into three groups and were polished with Astropol(group A),Sof-Lex(group B) and Super-snap(group C)respectively(n=3 for each resin).Specimens of natural enamel surface were used as the controls(group D).The surface roughness(Ra)and microstructure of the specimens were evaluated by an atomic force microscope(AFM).Results:Ra value in group A was lower than that in group B(P=0.015);Z350 XT resin obtained the lowest Ra value among the 5 kinds of resin specimens(P0.05).Conclusion:Astropol polishing instrument is better than Sof-Lex;Z350 XT has better polish performance.The three polishing instruments are ef-fective in polishing the 5 composite resins.
Résumé
Objective To study the relationship between drug resistance and expression of the gene associated with drug resistance in Candida albicans,as well as the secretory proteinase activity of these isolates.Methods The minimum inhibitory concentrations(MIC)to fouconzole and itraconazole in 99 strains of Candida albicans isolated from respiratory tract were measured by broth microdilution method,the M27-A protocol recommended by NCCLS.The gene expressions of CDR1 and MDR1 were semi-quantitatively determined by RT-RCR.The secretory proteinase activity of these isolates was assayed by plate with medium containing bovine serum albumin.Results The rates of drug resistance to fluconzole and itraconazole were 4% and 12.1% respectively.CDR1 expression in the susceptible dose-dependent(S-DD)isolates was higher than those in the susceptible isolates and drug-resistant isolates(P