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Objective To investigate the efficiency of different concentrations of genipin and silk fibroin (SF)∶ chitosan (CS) ratios on the package and release of SF-CS composite microspheres. Methods Selected the microspheres with a SF∶CS ratio of 1∶1 to encapsulate different concentrations of bovine serum albumin (BSA) and compared their encapsulation efficiency and sustained-release rate with those of pure chitosan microspheres. SF-CS microspheres were prepared with emulsion cross-linking technique. The microspheres were observed by scanning electron microscope. Size distribution was measured by a laser particle size analyzer. X-ray diffractometry (XRD), fourier transform infrared spectroscopy (FTIR) and thermogravimetricanalyzer (TGA) were used to analyze their structural characteristics. BCA method was used for determination of the drug entrapment, loading rate and cumulative release of the total drug. Results The five types of microspheres (m (CS): m (SF) = 1∶0.5, 0.1 g or 0.5 g genipin; m (CS)∶m (SF) = 1∶1, 0.05 g or 1 g genipin; m (CS)∶m (SF) = 1∶2, 0.5 g eniping) had a more spherical shape and smooth surface with particle size between 70-147 μm. The microspheres prepared with m (CS)∶m (SF) of 1∶1 and 0.05 g genipin in the presence of 10 mg,20 mg, or 50 mg BSA of BSA burst-released (30.79±3.43)%, (34.41±4.46)%, or (41.75±0.96)% of the entrapped BSA on the first day, and cumulatively released (75.20±2.52)%, (79.16±4.31)%, and (89.04±4.68)% in 21 d, respectively. The pure CS microspheres prepared in the presence of 10 mg BSA burst-released (39.53±1.76)% on the first day and cumulatively released (83.57±2.33)% of the total encapsulated BSA in 21 d. Conclusion The SF-CS composite microspheres had a higher sustained release rate than the pure CS microspheres and may be a better drug carrier.

Abstract: This study used RNA interference (RNAi) to explore the effect of NO and inducible nitric oxide synthase (iNOS) on apoptosis and proliferation in the tongue squamous carcinoma cell line Tca8113. Tca8113 cells were transfected with the plasmid pGenesil-1, which expresses iNOS short hairpin RNA (shRNA), or the negative control plasmid pSilencer-HK, and the transfected cells were compared with untransfected cells. The expression of iNOS was detected by histochemistry, and apoptosis was detected by flow cytometry. The expression of iNOS was significantly lower in the pSilencer-iNOS group than in the pSilencer-HK and empty control groups. The apoptosis rate was significantly higher in the pSilencer-iNOS group than in the pSilencer-HK and empty control groups. Growth monitoring showed that proliferation was also inhibited in cells transfected with pSilencer-iNOS. RNAi gene silencing decreased iNOS gene expression, induced apoptosis, and suppressed proliferation in Tca8113 cells. [Copyright &y& Elsevier]

Based on the daily sunspot number (SN) data (1954–2011) from the Purple Mountain Observatory, the extreme value theory (EVT) is employed for the research of the long-term solar activity. It is the first time that the EVT is applied on the Chinese SN. Two methods are used for the research of the extreme events with EVT. One method is the block maxima (BM) approach, which picks the maximum SN value of each block. Another one is the peaks-over-threshold (POT) approach. After a declustering process, a threshold value (here it is 300) is set to pick the extreme values. The negative shape parameters are obtained by the two methods, respectively, indicating that there is an upper bound for the extreme SN value. Only one value of the N -year return level (RL) is estimated: N = 19 years. For N = 19 years, the RL values of SN obtained by two methods are similar with each other. The RL values are found to be 420 for the POT method and the BM method. Here, the trend of 25th solar cycle is predicted to be stronger, indicating that the length of meridional forms of atmospheric circulation will be increased. [ABSTRACT FROM AUTHOR]