j. yu

The design of contraction pipes for efficient fluid transport and spraying applications requires a deep understanding of fluid dynamics and resistance characteristics. This study utilizes the infinitesimal element method to analyze the fluid motion within the cross-section of a circular contraction pipe and confirms that the wall shear stress is a function of the total pressure gradient and pipe diameter, in accordance with Stokes’ formula. Numerical simulations are employed to investigate the velocity distribution and transverse pressure loss pattern across the cross-section of the pipe. By making reasonable assumptions and conducting data fitting, we present a semi-empirical model that predicts pressure loss and local loss coefficients in small contraction pipes. This model is shown to be simpler, more accurate, and broadly applicable, compared with existing models. This study provides practical guidance for the design of contraction pipes and enhancement of the accuracy of pressure loss calculations, which are crucial for optimizing fluid transport systems.

Underwater explosions are applied across diverse sectors and present considerable risks to marine infrastructures. Therefore, precise prediction of shockwave loading characteristics for various charge shapes during underwater explosions is critical. This study presents a novel compressible multiphase fluid solver, developed to accurately simulate shockwave propagation and the dynamics of multiphase interfaces. A spatial discretization of the system equations utilizes a fifth-order Weighted Essentially Non-Oscillatory (WENO) scheme for reconstruction, whereas temporal discretization employs a third-order Total Variation Diminishing (TVD) scheme implemented via Runge–Kutta methods. Furthermore, the description of the detonation reaction incorporates a newly developed programmed burn model. The interface dynamics are captured through the application of the level-set method. The solver was initially validated by comparing the propagation results of detonation waves against established data in the literature. Both the simulated peak pressures and shockwave histories closely matched theoretical and experimental data. Different geometries of TNT charges were then analyzed to investigate shockwave propagation in near-field underwater explosions. The newly developed compressible multiphase solver, incorporating detonation reactions, precisely captured the early stages of shockwave propagation. This research offers vital technical insights for accurately predicting shockwave dynamics in near-field underwater explosions in complex scenarios.

One prevalent malignant tumor in the digestive system is gastric cancer (GC). Cortactin is an intracellular cytoskeleton protein and exerts the crucial function in GC development. However, the roles and mechanisms of cortactin in the invasion and metastasis of GC need further exploration.

Cortactin expression in GC tissues and cells via western blot and quantitative reverse transcription PCR. Cell migration and invasion were detected by the Transwell assays. Immunofluorescence staining and extracellular matrix (ECM) degradation assays verified the ability to invadopodium formation and ECM degradation.We then used gelatin zymography to identify the relationship between cortactin and matrix metalloproteinases (MMPs). The xenograft tumor model proved that cortactin can accelerate tumor growth and intraperitoneal metastasis in mice.

We found that cortactin is overexpressed in GC. cortactin overexpression facilitated cell migration and invasion, whereas cortactin silencing exerted the opposite function. cortactin can facilitate invadopodium formation and ECM degradation in GC cells. Cortactin can positively regulate matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) levels. Furthermore, Cortactin accelerate GC progression in vivo.

In short, this study confirmed that cortactin enhanced invadopodium formation to accelerate GC development through upregulating MMP2 and MMP9.

The hypersonic transient flow pass a blunt cone under three types of pulse disturbances is calculated using DNS. The response characteristic of hypersonic boundary layer among different types of pulse disturbance is compared. The distribution and evolution characteristics of disturbance modes are investigated by mode analysis. Results indicate that the receptivity characteristics induced by freestream pulse wave have both similarities and differences with that induced by freestream continuous wave. The interactions of different types of pulse waves with boundary layer and bow shock present different characteristics. The boundary layer thermodynamic characteristics under pulse fast acoustic wave are sensitive to mainstream disturbance wave, and that under pulse slow acoustic wave are sensitive to residual reflection wave. The type of pulse disturbance wave has a great influence on the production and mode distribution of boundary layer disturbance wave. In general, the disturbance amplitude in the pulse fast acoustic wave situation is the largest, the case of entropy wave is the second, and the case of slow acoustic wave is the smallest. For regional influence, the type of pulse disturbance has a huge impact on the disturbance modes in both the head and the non-head. For the three cases of pulse wave, the main mode group attenuation phenomenon which narrows the disturbance frequency band exists in the boundary layer. This group attenuation is the fastest for freestream slow acoustic wave, followed by entropy wave, and then fast acoustic wave. Under the action of pulse slow acoustic waves, the disturbance wave evolution of each order mode in the boundary layer along the streamwise is relatively stable, followed by entropy wave, and the case of fast acoustic wave is the most active.

A disease outbreak occurred in June 2012 among mud loach cultured on pond farms in Jangseong-gun، Jeollanam-do، Korea. Mortality rates reached up to 1. 2% in the farm per day. Typical clinical signs were bleeding ulcer at the middle portion of head and haemorrhagic erosion of the operculum. Based on biochemical characteristics، the causative bacterium isolated from diseased fish was identified as Aeromonas sobria. The isolate expressed two haemolytic genes، aerolysin (sob) and haemolysin (asa1) genes. Histopathologically، liver showed hepatocellular vacuolar degeneration and congestion in sinusoids. The spleen exhibited necrotized splenocytes and haemorrhagic pulps. In the kidney، glomerular destruction، renal tubular necrosis and haemorrhage were observed. Experimental infection (infectious dose of 106، 107، and 108 cfu fish-1) of healthy mud loach with the isolate resulted in the development of clinical signs similar to those seen in the farm. By injection with an infectious dose of 106 cfu fish-1، the mortality rate was 10. 3% within 7 days post infection. A mortality rate of 60. 9% was reached within 2 days when an infectious dose of 107 cfu fish-1 was used. Otherwise، all fish died within 1 day when injected with 108 cfu fish-1. The results demonstrated that A. sobria is involved in the morbidity and mortality of the farmed mud loach.