Role of inter-particle friction in granular materials under three dimensional conditions

The inter-particle friction is known to be an important contributor to the strength and deformation characteristics in granular materials. The mechanism of inter-particle friction to the macroscopic responses can be explained by microscopic investigations. Based on the discrete element method (DEM), a series of true triaxial tests for the cubic granular assembly are carried out and the effects of inter-particle friction coefficient (μ) on the evolutions of macro- and micromechanical parameters of granular materials are studied. The macroscopic stress, the distribution of coordination numbers and contact force with regard to strong and weak contact networks are concerned, as well as the corresponding fabric tensor and anisotropies. Findings indicate that increasing inter-particle friction sharpens the peak value of deviatoric stress and enhances the degree of dilatancy of the granular assembly at the macroscopic level. From the microscopic perspective, the distribution of the coordination number of the weak contact system varies dramatically, while the number of particles with smaller coordination number in the strong contact system changes little with different μ. Besides, the difference between strong and weak contact networks is enlarged, and anisotropy indicators are significantly enhanced, which strengthen the bearing ability of anisotropic stresses in granular materials

BEAM-TYPE ACOUSTIC METAMATERIAL DESIGN FOR VIBRATION SUPPRESSION WITH STRUCTURAL DAMPING

Vibration suppression of a beam-type acoustic metamaterial with periodic cavities filled by a viscoelastic membrane that supports a hollow mass still filled by a viscoelastic membrane that supports a local resonator is investigated. First, the proposed beam-type acoustic metamaterial is modeled as a one-dimensional mass-in-mass-in-mass (MMM) lumped parameter chain with structural damping, and then a mass-in-mass (MM) lumped parameter chain with structural damping is also given for comparison. For the two chains, the influence of structural damping on band structures are considered, and the loss factors associated with all propagating Bloch modes are compared. Finally, as an example, the beam-type metamaterials based on MM model with structural damping and MMM model with structural damping are designed to suppress vibration, respectively. The viscoelastic membranes act as structural damping. The finite element method based on Kirchhoff’s plate theory is developed to capture dynamic displacement fields of different metamaterials. Structural frequency response is calculated for different configurations of cantilevered structures when disturbance is considered. The results show that the proposed beam-type acoustic metamaterial based on MMM model with structural damping has higher dissipation and display high damping and does not sacrifice stiffness than MM model with structural damping

Glutathione S-Transferase alpha 4 promotes proliferation and chemoresistance in colorectal cancer cells

Glutathion

Wiskott-Aldrich syndrome gene as a prognostic biomarker correlated with immune infiltrates in clear cell renal cell carcinoma

IntroductionThe abnormal expression of the Wiskott-Aldrich syndrome protein (WASP) encoded by the Wiskott-Aldrich syndrome (WAS) gene has been implicated in tumor invasion and immune regulation. However, prognostic implications of WAS and its correlation tumor infiltrating in renal clear cell carcinoma (ccRCC) is not clear cut.MethodsThe correlation between WAS expression, clinicopathological variables and clinical outcomes were evaluated using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Tumor Immune Estimation Resource (TIMER), UALCAN, Gene Expression Profiling Interaction Analysis (GEPIA), Kaplan-Meier (KM) plotter and other databases. Furthermore, we assessed the transcription expression of WAS in renal cancer tissues, various renal carcinoma cell lines and human renal tubular cells (HK2) using quantitative polymerase chain reaction (qPCR). A comprehensive analysis of multiple databases including TIMER, GEPIA, TISIDB, ESTIMATE algorithm, and CIBERSORT algorithm were performed to determine the correlation between WAS and tumor infiltrating immune cells in ccRCC.ResultsThe results displayed an increase in WAS mRNA level in ccRCC compared to normal tissue. WAS protein level was found highly expressed in cancer tissues, particularly within renal tumor cells via the human protein atlas (HPA). Interestingly, we found that elevated WAS expression was significantly positively correlated with the infiltration of CD8+ T cells, B cells, Monocytes, Neutrophils, Macrophages, T cell regulation, NK cells, and Dendritic cells in ccRCC. Bioinformatics demonstrated a strong correlation between WAS expression and 42 immune checkpoints, including the T cell exhaustion gene PD-1, which is critical for exploring immunotherapy for ccRCC. We revealed that patients with high WAS expression were less sensitive to immunotherapy medications.ConclusionIn conclusion, our study identified that WAS was a prognostic biomarker and correlated with immune infiltrates in ccRCC