ABSTRACT
It is currently a challenge to accurately predict the deformation and fracture behavior of metal parts in automobile crashes. Many studies have shown that the deformation and fracture behavior of materials are significantly affected by the stress state during automobile crashes with complex stress state characteristics. In order to further promote the application of die-cast magnesium alloys in automobiles, it is particularly important to study the material deformation and fracture behavior of die-cast magnesium alloys. In this paper, the mechanical properties of the AM60B die-cast magnesium alloy sheet under four stress states (shear, tension, R10 notch tension, and cupping) were designed and tested. Based on the von Mises isotropic constitutive model and Swift weighted Hockett-Sherby hardening model, the plastic constitutive model of die-cast magnesium alloy was established. Based on the plastic model and the fracture model (JC, MMC, and DIEM) considering the influence of three stress states, the deformation and fracture behavior of the AM60B die-cast magnesium alloy front-end members in three-point bending were predicted by experiments and finite element simulation. The experimental results show that the deformation mode and loading-displacement curve trend of the AM60B die-cast magnesium alloy front members are the same, the crack initiation point and crack initiation time are the same, and the crack shape is similar. The results show that the complex stress state constitutive model parameters and the DIEM fracture model obtained in this paper can accurately predict the deformation and fracture failure behavior of the AM60B die-cast magnesium alloy sheet.
ABSTRACT
The proper clinical application of antibiotics is of great significance to guarantee medical quality and safety.However,with the widespread clinical use,the phenomenon of non-standard use is becoming increasingly obvious,and the bacteri-al drug resistance caused by it has seriously jeopardized human health.Based on the performance appraisal in a Class A tertiary public hospitals,this paper analyzed the current clinical application of antibiotics in a cancer hospital,and suggested multi-discipli-nary cooperative management be adpoted and multi =measures be taken simultaneously to significantly improve proper drug use.
ABSTRACT
The presence of the impurity element Fe significantly influences the overall performance of recycled aluminum alloy. This study aims to elucidate the impact of Fe content on the microstructure and tensile properties of friction-stir-welded (FSW) joints in recycled cast A356 aluminum alloy. Three samples with varying Fe content were prepared for FSW joints. The quality of the weld zone was meticulously assessed through macrostructure and microstructure analyses. The tensile strengths of the joints were carefully evaluated and correlated with the microhardness and microstructure of the weld zone. The research findings reveal that, among the three fabricated joints, the one with an Fe content of 0.3 wt.% demonstrates the most favorable tensile performance. This particular joint exhibits the highest tensile strength of 153 MPa, commendable yield strength of 90 MPa, and a favorable elongation of 5.7%. The mechanisms responsible for grain refinement in the weld nugget zone involve plastic deformation and dynamic recrystallization. Significantly, the disruptive effects of friction-stir action on eutectic silicon phases and rich iron phases emerge as crucial factors contributing to the enhanced performance of the weld nugget zone in the welded joint.
ABSTRACT
<p><b>OBJECTIVE</b>To detect the expression of Toll-like receptor 9 (TLR9) in ovarian cancer, and to explore their clinical significance.</p><p><b>METHODS</b>Western blot method and immunohistochemical staining were used to examine the expression of TLR9 in the ovarian cancer, paracancerous tissues and normal ovarian tissues, obtained during operation from 30 ovarian carcinoma patients and 30 normal non-tumor patients. The relationships of TLR9 with pathological grade, clinical stage, and metastasis of ovarian cancer were statistically analyzed.</p><p><b>RESULTS</b>The percentage of positive cells expressing TLR9 protein in human ovarian cancer tissues, paracancerous tissues and normal ovarian tissues were 80.0%, 36.7% and 20.0%, respectively. The protein expression level of TLR9 was gradually descending (P < 0.01). The highly expressed TLR9 significantly correlated with the degree of tumor differentiation, an advanced FIGO stage and lymph node metastasis. The Western blot results showed that TLR9 protein expression in ovarian cancer, paracancerous tissues and normal ovarian tissues were 0.803 ± 0.072, 0.411 ± 0.087 and 0.113 ± 0.065, respectively. The expression of TLR9 in ovarian cancer was significantly higher than that in normal tissue and paracancerous tissues (P < 0.01).</p><p><b>CONCLUSIONS</b>TLR9 has a higher expression in ovarian cancer tissues. TLR9 expression has a close relationship with pathological grades of ovarian cancer, suggesting that TLR9 plays an important role in the development and progression of ovarian cancer through immunologic mechanisms.</p>