A strain-gradient crystal plasticity constitutive model was developed in order to predict the Hall Petch behavior of a Ni-base polycrystalline superalloy. The constitutive model involves statistically stored dislocation and geometrically necessary dislocation densities, which were incorporated into the Bailey-Hirsch type flow stress equation with six strength interaction coefficients. A strain-gradient term (called slip-system lattice incompatibility) developed by Acharya was used to calculate the geometrically necessary dislocation density. The description of Kocks-Argon-Ashby type thermally activated strain rate was also used to represent the shear rate of an individual slip system. The constitutive model was implemented in a user material subroutine for crystal plasticity finite element method simulations. The grain size dependence of the flow stress (viz., the Hall- Petch behavior) was predicted for a Ni-base polycrystalline superalloy NIMONIC PE16. Simulation results showed that the present constitutive model fairly reasonably predicts 0.2%-offset yield stresses in a limited range of the grain size.

The cholesterol lowering effect of vegetables fermented by Lactobacillus plantarum HY7712 was evaluated in rats fed high fat/high cholesterol diet. SD Rats were randomly divided into three groups, then fed a normal diet (ND), a highfat high-cholesterol diet (HFCD), or HFCD and vegetables fermented by HY7712 (VFLAB) for 5 weeks, and the biomarkers in the blood, liver, and feces of rats were measured. Antioxidant status such as SOD, CAT, GSH/GSSG, and MDA was significantly deteriorated in HFCD compared with ND (p<0.01) but was improved in VFLAB to the level of ND. In addition, the level of MDA in VFLAB was significantly decreased in comparison with HFCD (p<0.05). Total cholesterol, LDLcholesterol, and atherogenic index (AI) were significantly increased in HFCD, but significantly decreased in VFLAB (p<0.05). In addition, administration of a HFCD diet increased the fecal bile acid in rats and the concentration of fecal bile acid was higher in VFLAB than in HFCD. In conclusion, the vegetables fermented by L. plantarum HY7712 improved antioxidant status and hypercholesterolemia induced by HFCD diet, which may be due to the synergic effect of lactic acid bacteria and fermented vegetables.