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The high-speed ice-ball impact damage research of epoxy resin/carbon fiber 3D four-way braided composites was carried out. Using the air gun impact test system, ice balls with three different impact velocities were used to conduct impact tests. After the test, industrial CT scans were performed on the main damage positions of the test pieces, and the internal damage forms were observed. The composite macro constitutive model based on surface unit-cell and interior unit-cell and a strain rate related material model of the ice were used to establish the finite element model. The simulation model was compared with the test. The results show that the damage of the matrix in the surface unit-cell area is more serious than that in the interior unit-cell area, the damage area of the front surface is generally larger than that of the back surface, the oblique impact angle has an influence on the damage area and damage location. As the impact angle decreases, the damage area of the composite material also decreases. Increasing the thickness of plate can improve the ability to absorb energy and reduce the damage area of the material.

A comprehensive computational micromechanics has been presented to predict the transverse mechanical properties and failure envelop of bi-axial stress in a 22-33 plane at high temperatures. First, a paraboloidal elasto-plastic damage model considering the temperature effect of epoxy has been employed. Then, in order to rapidly create the random fiber distribution of the representative volume element (RVE), a simple and effective algorithm of fiber placement and an auto modeling and calculating python script have been developed, where the thickness size effect of RVEs has been discussed. Finally, the transverse tension/compression and out-of-plane shear properties and the corresponding failure envelop of RVEs are analyzed systematically by means of finite element simulations. The results show that the in-plane shear strength exists strongly thickness size effect, and high temperature can significantly weaken the transverse strength, especially for transverse compression, and the temperature effect of modulus can be depicted by a specific Gaussian function. In addition, Hashin and Tsai-wu criteria may be more appropriate to predict the bi-axial failure envelop of σ 2 2 − τ 23 at high temperature, and Tsai-Wu criterion is better and more suitable than Hashin and Catalanotti criteria for considering bi-axial compression. [ABSTRACT FROM AUTHOR]

A direct implicit discretization approach is presented for an arbitrary non-conformal interface by using a virtual cell on unstructured meshes. In this study, the virtual cell is supposed to be located at the neighbour of a target cell adjacent to the non-conformal interface. Any computational value on a virtual cell is formulated as a linear combination of values on contribution cells, which are determined by the nearest neighbouring cells or surface intersecting cells. The linear formulation simplifies the process of implementing implicit discretization for the governing equations. The approach is simple and efficient for information transfer through the interface because it avoids mesh stitching or iterations based on explicit discretization for treating topologically inconsistent meshes. Several numerical tests verify that the proposed method is capable and efficient for dealing with the arbitrary non-conformal interface. [ABSTRACT FROM AUTHOR]

With the rapid development of human-machine interactions and artificial intelligence, the demand for wearable electronic devices is increasing uncontrollably all over the world; however, an unsustainable power supply for such sensors continues to restrict their applications. In the present work, piezoelectric barium titanate (BaTiO 3 ) ceramic powder with excellent properties was prepared from milled precursors through a solid-state reaction. To fabricate a flexible device, the as-prepared BaTiO 3 powder was mixed with polydimethylsiloxane (PDMS) polymer. The BaTiO 3 /PDMS ink with excellent rheological properties was extruded smoothly by direct ink writing technology (DIW). BaTiO 3 particles were aligned due to the shear stress effect during the printing process. Subsequently, the as-printed composite was assembled into a sandwich-type device for effective energy harvesting. It was observed that the maximum output voltage and current of this device reached 68 V and 720 nA, respectively, for a BaTiO 3 content of 6 vol %. Therefore, the material extrusion-based three-dimensional (3D) printing technique can be used to prepare flexible piezoelectric composites for efficient energy harvesting.

Structured illumination microscopy (SIM) has become one of the most significant super-resolution techniques in bioscience for observing live-cell dynamics, thanks to fast full-field imaging and low photodamage. However, artifact-free SIM super-resolution reconstruction requires precise knowledge about variable environment-sensitive illumination parameters. Conventional algorithms typically, under the premise of known and reliable constant phase shifts, compensate for residual parameters, which will be easily broken by motion factors such as environment and medium perturbations, and sample offsets. In this Letter, we propose a robust motion-resistant SIM algorithm based on principal component analysis (mrPCA-SIM), which can efficiently compensate for nonuniform pixel shifts and phase errors in each raw illumination image. Experiments demonstrate that mrPCA-SIM achieves more robust imaging quality in complex, unstable conditions compared with conventional methods, promising a more compatible and flexible imaging tool for live cells.

Glioma, the most common intrinsic tumor of the central nervous system, is characterized by its high incidence and poor prognosis. The aim of this study was to identify differentially expressed genes (DEGs) between glioblastoma multiforme (GBM) and low-grade glioma (LGG) to explore prognostic factors of different grades of gliomas. Single-cell transcriptome sequencing data of gliomas were collected from the NCBI Gene Expression Omnibus (GEO), which included a total of 29 097 cell samples from three datasets. For the analysis of human gliomas of different grades, 21 071 cells were obtained by filtering, and 70 genes were screened from differentially expressed genes by gene ontology (GO) analysis, Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, from which the gene DLL3 was focused by reviewing the literature. The TCGA-based gene expression profiling interactive analysis (GEPIA) database was used to explore the survival curves of genes in LGG and GBM, and the gene expression profiling interactive analysis and tumor immune estimation resource (TIMER) database was used to study the expression of key genes in gliomas of different grades, predicting biomarkers that were closely related to immunotherapy. The cBioPortal database was used to explore the relationship between DLL3 expression and 25 immune checkpoints. Gene set enrichment analysis (GSEA) further identified pathways associated with central genes. Finally, the efficacy of biomarkers in prognosis and prediction was validated in the Chinese glioma genome atlas (CGGA). These results demonstrated that prognostic genes are associated with tumor proliferation and progression. Analysis of biological information and survival suggested that these genes might serve as a promising prognostic biomarker and as new targets for selecting therapeutic strategies.

Retinoblastoma (RB) is the most common intraocular malignant tumor in infants and young children. The key causative factors in the progression of RB remain unclear. Therefore, identifying genes closely associated with RB progression may provide important clues for disease diagnosis and gene therapy. However, tumor tissues have strong cellular heterogeneity. There may be significant differences in cell function and gene expression among cells in different pathological states. In this study, we downloaded single-cell transcriptome sequencing data of RB tumors and adjacent tissues from the GEO public database. Subsequently, we analyzed RB tumor transcriptional profiles with different disease duration at the single-cell level and identified cell groups and gene sets potentially associated with RB progression. The results showed that the tumor tissue and the adjacent tissues had overall consistency in the single-cell transcriptional map, but there were obvious differences in the distribution proportions of G1 phase cells, G2 phase cells, and microglia cells of cone precursors in RB tumor and the adjacent tissues. Furthermore, the role of three cell populations in the progression of RB tumors was emphatically analyzed. We found that in the early stage of RB tumors, cone precursor cells proliferated abnormally in G1 phase. With the progression of RB tumors, the proportion of cone precursor cells in G2 phase increased significantly. Meanwhile, the results of differential analysis of microglial populations during RB progression showed that the key genes mainly involved in immune response include RPL23 , B2M , and HLA superfamily genes. This study provides new perspectives and data resources for the research of RB pathogenesis and progress.