A numerical simulation is performed for thermal instability and heat transfer of viscoelastic fluids in bounded porous media under the bottom constant heat flux boundary condition. The results for six different combinations of relaxation and retardation times demonstrate the existence of the thermal instability induced flow bifurcation. It is found that the increase of the relaxation time can enhance the heat transfer efficiency by disturbing the fluid flow and facilitating the bifurcation. The increase of the retardation time can stabilize the flow and postpone the bifurcation, leading to simpler flow pattern and lower heat transfer rate.
The effects of two viscoelastic parameters on the thermal convection of a viscoelastic Oldroyd-B fluid in an open-top porous square box with constant heat flux are investigated. The results show that the increase of relaxation time is able to destabilize the fluid flow leading to a higher heat transfer rate, while the increase of retardation time tends to stabilize the flow and suppress the heat transfer. The flow bifurcation appears earlier with the increase of the relaxation time and the decrease of the retardation time, re- suiting in more complicated flow patterns in the porous medium.
In cardiac myocytes,the sarcoplasmic reticulum(SR)is the main storage organelle of free Ca^(2+).The concentration of free Ca^(2+)in the SR is 0.5–1.0 mmol/L and is 2–3 orders of magnitude greater than that in the cytosol.The SR is composed of interconnected cisternae(junctional SR,i.e.,JSR)and tubules(free SR network,i.e.,FSR)that extend throughout the cytosol[1].Ca^(2+)is released from the JSR into the cytosol via Ca^(2+)release units(CRUs,
Jinghui LiWenjun XieXi ChenYunlong HuoHeping ChengWenchang Tan
Objective To investigate the effect of IMPX977 on methyl-Cp G-binding protein 2（MeCP2） expression in rats. Methods Forty-eight SD rats were randomly divided into four groups： normal control group, olive oil（negative control, 5 mL/kg oil） group, and 10 mg/kg and 30 mg/kg IMPX977 administration groups. All rats were given corresponding dose of drugs each other day and administered orally for two weeks. Tissues including cortex and cerebellum were collected from rats to assay the expression of MeCP2 by quantitative RT-PCR and Western blotting. Results The IMPX977 supplement showed no significant effect on the body weight of rats. In normal rats, MeCP2 was highly expressed in cerebellum, cortex and hippocampus, and less expressed in heart, spleen and lung. In addition to male rats, compared with the control group, the expression of MeCP2 mRNA was significantly increased in cerebellum after 30 mg/kg IMPX977 treatment and contrarily, absolutely decreased in cortex of all treatment groups. Furthermore, in female rats MeCP2 mRNA was reduced in cortex of both olive oil and 30 mg/kg IMPX977 treatment groups compared with control group. Meanwhile, MeCP2 protein level was significantly elevated in cerebellum of treated male rats compared to the control group. In contrast to the control group, the expression of MeCP2 protein in both cerebellum and cortex of female rats in other three groups was increased. Conclusion IMPX977 treatment（10 mg/kg） may elevate the expression of MeCP2, which establishes experimental foundation for the further research on rat models of Rett syndrome.
Ya HuLiang LeLi-xin QiYing ZhaoHui FuChen DuanXiao-ying WangKe-ping Hu
