RESUMO
The mining rope shovel (MRS) is one of the core pieces of equipment for open-pit mining, and is currently moving towards intelligent and unmanned transformation, replacing traditional manual operations with intelligent mining. Aiming at the demand for online planning of an intelligent shovel excavation trajectory, an MRS excavating trajectory planning method based on material surface perception is proposed here. First, point cloud data of the material stacking surface are obtained through laser radar to perceive the excavation environment and these point cloud data are horizontally calibrated and filtered to reconstruct the surface morphology of the material surface to provide a material surface model for calculation of the mining volume in the subsequent trajectory planning. Second, kinematics and dynamics analysis of the MRS excavation device are carried out using the Product of Exponentials (PoE) and Lagrange equation, providing a theoretical basis for calculating the excavation energy consumption in trajectory planning. Then, the trajectory model of the bucket tooth tip is established by the method of sixth-order polynomial interpolation. The unit mass excavation energy consumption and unit mass excavation time are taken as the objective function, and the motor performance and the geometric size of the MRS are taken as constraints. The grey wolf optimizer is used for iterative optimization to realize efficient and energy-saving excavation trajectory planning of the MRS. Finally, trajectory planning is carried out for material surfaces with four different shapes (typical, convex, concave, and convex-concave). The results of experimental validation show that the actual hoist and crowd forces are essentially consistent with the planned hoist and crowd forces in terms of the peak value and trend variations, verifying the accuracy of the calculation model and confirming that the full bucket rate and various parameters meet the constraints. Therefore, the trajectory planning method based on material surface perception are feasible for application to different excavation conditions.
RESUMO
Mastitis is a common disorder in women capable of altering the normal physiological function of the mammary gland. It has been reported that mammary epithelial cells (MECs) could be involved in treating mastitis by regulating the inflammatory response and miR-155 might participate in this process. However, the effects of MECs-derived exosomal miR-155-inhibitor in treating mastitis and the regarding mechanism are still unknown. In our study, mouse mammary epithelial cells (HC11) were applied to study the role of MECs-derived exosomal miR-155-inhibitor in the treatment of mastitis and explore the mechanism. Results in our study showed that specific markers including CD63 and Apo-A1 were expressed in blank exosomes and exosomes containing miR-155-inhibitor isolated from transfected HC11 cells. Results of immunofluorescence showed that the blank exosomes and exosomes (containing miR-155-inhibitor) labeled with PKH26 were absorbed in HC11 cells. The level of miR-155 was decreased obviously in Engineered exosomes with miR-155-inhibitor and HC11 cells Transfected with exosome containing miR-155-inhibitor. The level of miR-155 was increased and cell apoptosis was promoted obviously in HC11 cells induced by LPS, however, they were decreased obviously after transfecting with an exosome containing miR-155-inhibitor. The level of TLR2, TLR4, TLR6, NF-κB, TNF-α, and IL-1ß was increased obviously in LPS-induced HC11 cells, however, they were decreased obviously after transfecting with an exosome containing miR-155-inhibitor. The change in IL-10 level is opposite to the above genes. Taken together, exosomal miR-155-inhibitor could decrease the apoptosis of MECs and inhibit the inflammatory response to treat mastitis by down-regulation in the TLRs/NF-κB signaling pathway, which might be a new therapeutic target for mastitis.
