No abstract

No abstract

No abstract

This paper presents an averaging method to link discrete to continuum variables of granular materials. Compared to the other methods proposed in the literature, it has advantages of being applicable to all flow regimes, and to granular flows with or without the effect of physical boundaries. Its application is demonstrated in the determination of the macroscopic properties such as mass density, velocity, stress, and couple stress distributions of a hopper flow, where the discrete results are generated by means of discrete particle simulation. While highlighting the need for considering properly the effect of physical boundaries, the results indicate that the proposed method is an effective way to determine the flow properties of granular materials.

This paper reports a numerical study of solid flow in a model blast furnace under simplified conditions by means of discrete particle simulation (DPS). The applicability of the proposed DPS approach is validated from its good agreement with the experiment in terms of solid flow patterns. It is shown that the DPS is able to generate a stagnant zone without any need for any arbitrary treatment, and capture the main features of solid flow within the furnace at a microscopic level. The results confirm that the solid flow in a blast furnace can be divided into four different flow regions. However, the flow is strongly influenced by the front and rear walls in a 2D slot model furnace whereas the predicted stagnant zone decreases significantly with wall sliding friction. In a 3D model with periodic boundary conditions incorporated, a smaller stagnant zone is obtained. The effects of solid flow rate, particle properties such as sliding and rolling friction coefficients on the solid flow are also investigated. The results are analysed in terms of solid flow patterns, solid velocity field, porosity distribution and normal force structure. The implication to blast furnace operation is discussed.

No abstract

The molecular signaling mechanisms of Coenzyme Q10 (CoQ10) in diabetic nephropathy (DN) remain poorly understood. We verified that mitochondrial abnormalities, like defective mitophagy, the generation of mitochondrial reactive oxygen species (mtROS) and the reduction of mitochondrial membrane potential, occurred in the glomerulus of db/db mice, accompanied by reduced PINK and parkin expression and increased apoptosis. These changes were partially reversed following oral administration of CoQ10. In inner fenestrated murine glomerular endothelial cells (mGECs), high glucose (HG) also resulted in deficient mitophagy, mitochondrial dysfunction and apoptosis, which were reversed by CoQ10. Mitophagy suppression mediated by Mdivi-1 or siPINK abrogated the renoprotective effects exerted by CoQ10, suggesting a beneficial role for CoQ10-restored mitophagy in DN. Mechanistically, CoQ10 restored the expression, activity and nuclear translocation of Nrf2 in HG-cultured mGECs. In addition, the reduced PINK and parkin expression observed in HG-cultured mGECs were partially elevated by CoQ10. CoQ10-mediated renoprotective effects were abrogated by the Nrf2 inhibitor ML385. When ML385 abolished mitophagy and the renoprotective effects exerted by CoQ10, mGECs could be rescued by treatment with mitoTEMPO, which is a mtROS-targeted antioxidant. These results suggest that CoQ10, as an effective antioxidant in mitochondria, exerts beneficial effects in DN via mitophagy by restoring Nrf2/ARE signaling. In summary, CoQ10-mediated mitophagy activation positively regulates DN through a mechanism involving mtROS, which influences the activation of the Nrf2/ARE pathway.

No abstract