Electroacupuncture Regulates TRPV1 through PAR2/PKC Pathway to Alleviate Visceral Hypersensitivity in FD Rats

Visceral hypersensitivity (VH) is the predominant pathogenesis of functional dyspepsia (FD). Duodenal hypersensitivity along with nausea further reduces the comfort level in gastric balloon dilatation and inhibits gastric receptive relaxation. The potential mechanism behind electroacupuncture- (EA-) mediated alleviation of VH has not been elucidated. In an FD rat model with tail clamping stress, iodine acetamide (IA) induced VH. The rats were treated with EA with or without PAR2 antagonist FSLLRY-NH2, and the body weight, gastric sensitivity, compliance, and gastrointestinal motility were determined. Mast cells and activated degranulation were stained with toluidine blue (TB) staining and visualized under a transmission electron microscope (TEM). Immunofluorescence was used to detect the expression of PAR2, PKC, and TRPV1 in the duodenum and dorsal root ganglion (DRG) and that of CGRP, SP in DRG, and c-fos in the spinal cord. EA alone and EA + antagonist enhanced the gastrointestinal motility but diminished the expression of TRPV1, CGRP, SP, and c-fos-downstream of PAR2/PKC pathway and alleviated VH in FD rats. However, there was no obvious superposition effect between the antagonists and EA + antagonists. The effect of EA alone was better than that of antagonists and EA + antagonists 2 alone. EA-induced amelioration of VH in FD rats was mediated by TRPV1 regulation through PAR2/PKC pathway. This protective mechanism involved several pathways and included several targets.

Comparative Analysis of Monitoring Methods for Vortex-induced Vibration of Multistage Pressure Reducing Valves

In this paper, a multistage pressure reducing valve is presented. The main frequency of vortex-induced vibration is evaluated by monitoring the lift coefficient during vortex shedding and the pressure fluctuation formed after vortex shedding in the flow field. By comparative analysis of two different methods, the number of vortices is relatively small at small openings. Due to the limitations of the location and quantity of monitoring points, accurately locating the most active position where pressure fluctuation occurs is difficult. Monitoring the lift coefficient is more suitable to evaluate the main frequency of vortex-induced vibration. At medium and large openings, due to the increase in the number of vortices, the superposition effect of the pressure fluctuation and the influence of the flow channel shape is more obvious. Monitoring the pressure fluctuation is more appropriate to evaluate the main frequency of vortex-induced vibration the valve. Therefore, a combination of the two methods can more accurately evaluate the vortex-induced vibration characteristics of the valve. When monitoring pressure fluctuation, the position and number of monitoring points directly affect the evaluation accuracy. The pressure fluctuations around the outlet and the multilayer sleeve are more active. It is more meaningful to monitor the pressure fluctuation at these points. The main frequency of the pressure fluctuation at these points better reflects the vortex-induced vibration characteristics of the valve.

Superposition Effect of the Leading Edge Film On the Downstream Film Cooling of a Turbine Vane Under Combustor Swirling Outflow

To investigate the superposition effect of the leading edge film on the downstream film cooling under swirling inflow, numerical simulations with three vane models (vane with films on the leading edge only, vane with films on the pressure side and suction side only, full-film cooling vane), two inlet conditions (axial inlet and swirling inlet) are conducted. The results indicate that the leading edge is the area where the film is most affected by the swirling inflow. For full-film cooling vane, the film on the leading edge does not always improve or even reduce the downstream film cooling. Flow mechanism analysis shows that the velocity direction near the downstream wall is governed by the interaction between the direction of swirling inflow and the direction of film hole incidence on the leading edge. A new type of leading edge film proposed by the author is also investigated, with the dividing line of the counter-inclined film-hole row coinciding with the twisted stagnant line to ensure that all films are incident at angles inverse to the direction of the swirling inflow. The new leading edge film successfully changes the velocity direction near the downstream wall and suppresses the deflecting effect on the downstream film. The new leading edge film can increase the overall area averaged cooling effectiveness of the full-film cooling vane by 10%, 15%, 18% and reduce the inhomogeneity by 13%, 19%, 27% over the traditional design, as the coolant mass flow increases.

Deformation superposition effect of asphalt mixture based on experiments and micromechanical modeling

Under multi-wheel heavy load, the asphalt mixture is prone to exhibit the deformation superposition effect, which exacerbates the damage of pavement structure. Multi-point penetration tests and numerical simulations by discrete element method (DEM) are performed to investigate the deformation superposition effect and micromechanical characteristics of asphalt mixture. The effect of wheel spacing, wheel group, and the evolution of micromechanical deformation superposition behavior are analyzed. Results indicate that the deformation superposition resistance of the asphalt mixture under the multi-wheel load decreases dramatically with the decrease in wheel spacing and the increase in the number of wheels, specifically the wheel spacing is 54 mm and the number of wheels is 4. The DEM simulations reflect the micromechanical property of asphalt mixture in the multi-point penetration test. The reduction of tensile chains is the internal reason for asphalt mixture deformation superposition, indicating the decrease of the adhesive strength of the material. A remarkably positive correlation is found between the reduction of the tensile chain and the deformation effect coefficient. In the process of superposition, the aggregate skeleton force chains are gradually destroyed and decrease to zero until cracking. The numerical simulation outcome is consistent with the laboratory penetration test outcome.

Deformation Superposition Effect of Asphalt Mixture Based on Experiments and Micromechanical Modeling

Under multi-wheel heavy load, the asphalt mixture is prone to exhibit the deformation superposition effect, which exacerbates the damage of pavement structure. Multi-point penetration tests and numerical simulations by discrete element method (DEM) are performed to investigate the deformation superposition effect and micromechanical characteristics of asphalt mixture. The effect of wheel spacing, wheel group, and the evolution of micromechanical deformation superposition behavior are analyzed. Results indicate that the deformation superposition resistance of the asphalt mixture under the multi-wheel load decreases considerably with the increase in wheel spacing and the number of wheels. The DEM simulations reflect the micromechanical property of asphalt mixture in the multi-point penetration test. The reduction of tensile chains is the internal reason for asphalt mixture deformation superposition, indicating the decrease of the adhesive strength of the material. A remarkably positive correlation is found between the reduction of the tensile chain and the deformation effect coefficient. In the process of superposition, the aggregate skeleton force chains are gradually destroyed and decrease to zero until cracking. The numerical simulation outcome is consistent with the laboratory penetration test outcome.

Improvement of Boeing Bump Method Considering Aircraft Vibration Superposition Effect

Pavement evaluation is critical for the decision-making process of pavement preservation and rehabilitation. Roughness is a key airport pavement characteristic that has been linked to impacts such as safety and service life. The Boeing Bump is one of the few roughness evaluation methods that has been developed specifically for runways. Although it is superior to the widely used International Roughness Index (IRI), it does not take into account the superposition effect of continuous runway bumps. Based on the ADAMS/Aircraft virtual prototype platform, this paper establishes and verifies five typical models (B737, B747, B757, B777, and B787) and then analyzes the most unfavorable speed (in terms of aircraft vibration) of each model and the dynamic responses caused by multiple bumps. The original Boeing Bump is improved and optimized by determining dynamic response thresholds for the various aircraft types. The results show that the revised Boeing Bump is more realistic than the original version, especially with regard to medium and long wave bands.