Synergistic effect of a novel oxymatrine-baicalin combination against hepatitis B virus replication, a smooth muscle actin expression and typeⅠcollagen synthesis in vitro

AIM： To study the effect of oxymatrine-baicalin combination （OB） against HBV replication in 2.2.15 cells and α smooth muscle actin （ α SMA） expression, type I, collagen synthesis in HSC-T6 cells. METHODS： The 2.2.15 cells and HSC-T6 cells were cultured and treated respectively. HBsAg and HBeAg in the culture supernatants were detected by ELISA and HBV DNA levels were determined by fluorescence quantitative PCR. Total RNA was extracted from HSC-T6 cells and reverse transcribed into cDNA. The cDNAs were amplified by PCR and the quantities were expressed in proportion to β actin. The total cellular proteins extracted from HSC-T6 cells were separated by electrophoresis. Resolved proteins were electrophoretically transferred to nitrocellulose membrane. Protein bands were revealed and the quantities were corrected by β actin. RESULTS： In the 2.2.15 cell culture system, the inhibitory rate against secretion of HBsAg and HBeAg in the OB group was significantly stronger than that in the oxymatrine group （HBsAg, P = 0.043; HBeAg, P = 0.026; respectively）; HBV DNA level in the OB group was significantly lower than that in the oxymatrine group （P = 0.041）. In HSC-T6 cells the mRNA and protein expression levels of α SMA in the OB group were significantly lower as compared with those in the oxymatrine group （mRNA, P = 0.013; protein, P = 0.042; respectively）; The mRNA and protein expression levels of type I collagen in the OB group were significantly lower as compared with those in the oxymatrine group （mRNA, P 〈 0.01; protein, P 〈 0.01; respectively）.CONCLUSION： OB combination has a better effect against HBV replication in 2.2.15 cells and is more effective against α SMA expression and type I collagen synthesis in HSC-T6 cells than oxymatrine in vitro.

Finite element analysis of temperature and stress fields during selective laser melting process of Al−Mg−Sc−Zr alloy

A 3D finite element model was established to investigate the temperature and stress fields during the selective laser melting process of Al−Mg−Sc−Zr alloy.By considering the powder−solid transformation,temperaturedependent thermal properties,latent heat of phase transformations and molten pool convection,the effects of laser power,point distance and hatch spacing on the temperature distribution,molten pool dimensions and residual stress distribution were investigated.Then,the effects of laser power,point distance and hatch spacing on the microstructure,density and hardness of the alloy were studied by the experimental method.The results show that the molten pool size gradually increases as the laser power increases and the point distance and hatch spacing decrease.The residual stress mainly concentrates in the middle of the first scanning track and the beginning and end of each scanning track.Experimental results demonstrate the accuracy of the model.The density of the samples tends to increase and then decrease with increasing laser power and decreasing point distance and hatch spacing.The optimum process parameters are laser power of 325−375 W,point distance of 80−100μm and hatch spacing of 80μm.

Microstructures and mechanical properties of in-situ TiB2/Al−xSi−0.3Mg composites

In-situ 2 vol.%TiB2 particle reinforced Al−xSi−0.3Mg(x=7,9,12,15 wt.%)composites were prepared by the salt−metal reaction,and the microstructures and mechanical properties were investigated.The results show that the TiB2 particles with a diameter of 20−80 nm and the eutectic Si with a length of 1−10μm are the main strengthening phases in the TiB2/Al−xSi−0.3Mg composites.The TiB2 particles promote grain refinement and modify the eutectic Si from needle-like to short-rod shape.However,the strengthening effect of TiB2 particles is weakened as the Si content exceeds the eutectic composition,which can be attributed to the formation of large and irregular primary Si.The axial tensile test results and fractography observations indicate that these composites show more brittle fracture characteristics than the corresponding alloy matrixes.