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INTRODUCTION: Intracellular reactive oxygen species (ROS) and nitric oxide (NO) levels are associated with vascular homeostasis and diseases. Exercise can modulate ROS and NO production through increasing frequency and magnitude of wall shear stress (WSS). However, the details of ROS and NO production in endothelial cells and their interplay under WSS induced by exercise at different intensities remain unclear. METHODS: In this study, we developed an in vitro multicomponent nonrectangular flow chamber system to simulate pulsatile WSS waveforms induced by moderate and high intensity exercise. Furthermore, the dynamic responses of ROS and NO in endothelial cells and the relationship between ROS and NO were investigated under the WSS induced by different intensity exercise. RESULTS: After exposing to WSS induced by moderate intensity exercise, endothelial cells produced more NO than those under high intensity exercise-induced WSS. In this process, ROS was found to play a dual role in the generation of intracellular NO. Under WSS induced by moderate intensity exercise, modest elevated ROS promoted NO production, whereas excessive ROS in endothelial cells exposed to WSS induced by high intensity exercise attenuated NO bioavailability. Interestingly, antioxidant N-acetylcysteine (NAC) could increase NO production under WSS induced by high intensity exercise. CONCLUSIONS: Our results provide some cues for selecting appropriate exercise intensities and elevating benefits of exercise on endothelial function. Additionally, owing to the consistency of our results and some in vivo phenomena, this flow chamber system may serve as an in vitro exercise model of arterial vessel for future studies.

The optical properties of silicon nanowires (Si NWs) coated with metallic nanoparticles (NPs) were theoretically investigated. A three dimensional (3D) model of a solar cell has been proposed, in which the Si NWs were geometrically modeled to be periodically aligned nano-pillars in a square lattice. Hemispherical metallic NPs were coated onto a sidewall of Si NWs. We numerically studied the optical properties of the structure with the finite element method (FEM) by using the commercial software COMSOL Multiphysics. It is demonstrated that the electromagnetic field is strongly localized around the metallic NPs as well as between the metallic NPs and Si NWs. Localized surface plasmons (LSPs) are generated around the metallic NPs, coupling and scattering a large amount of light into the Si NWs. A significant enhancement of the light absorption is observed, especially in the long wavelength range of the solar spectrum. These theoretical investigations agree well with our experimental data while providing a fundamental background for improving the efficiency of Si NWs solar cells.

A new system for simultaneous electrodeposition of U, Np, Pu, Am and Cm has been developed. The system consists of (NH4)2C2O4−H2SO4−HCl. The effects on recovery of pH, current density, interfering ions and the amount of added HCl have been studied. The optimum condition for simultaneous electrodeposition of actinides has been recommended. Under the recommended condition recoveries of U, Np, Pu, Am and Cm have been obtained by using232U,237Np,241Am,242Pu and244Cm. The counting sources prepared are uniform, adherent and suitable for α-spectrometry.