This paper investigates energy absorption performance of multi-cell tubes considering the influence of axial constrain in bending process Firstly, three-point-bending tests and fully clamped bending ...tests were conducted. Experimental results showed that the energy absorption of tubes increased to 2.5–3 times if the end of the tube is constrained. Based on the FE model verified by experiments, the effect of rib direction and rib number is investigated under fully clamped condition. Results show that the multi-cell tubes with rib parallel to the load direction (MT-Y0Zn) have better energy absorption performance than that with rib perpendicular to the load direction (MT-YnZ0), especially in the frontal part of bending process. Meanwhile, following with the increase of rib number, specific energy absorption (SEA) of MT-Y0Zn increases gradually, while SEA of MT-YnZ0 remains almost unchanged. Considering the fact that MT-Y0Zn shows better energy absorption performance, theoretical model of MT-Y0Zn is established and highly consistent with FE model. Finally, the influence of thickness and cross-section size is discussed. SEA increases with increase of cross-section and remains unchanged with increase of thickness as predicted by theory. However, when cross-section exceeds 80 mm or thickness is smaller than 1 mm, local denting caused by shear force decreased SEA significantly.
•Three-point-bending and fully clamped bending tests are conducted on multi-cell tubes.•FE models of multi-cell tubes under fully clamped condition are established and verified.•Effect of rib number and direction is studied under fully clamped condition.•Theoretical analysis is conducted on multi-cell tubes under fully clamped condition.•Theoretical and FE model are used to discuss the influence of cross-section size and thickness.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To identify somatic mutations in pediatric diffuse intrinsic pontine glioma (DIPG), we performed whole-genome sequencing of DNA from seven DIPGs and matched germline tissue and targeted sequencing of ...an additional 43 DIPGs and 36 non-brainstem pediatric glioblastomas (non-BS-PGs). We found that 78% of DIPGs and 22% of non-BS-PGs contained a mutation in H3F3A, encoding histone H3.3, or in the related HIST1H3B, encoding histone H3.1, that caused a p.Lys27Met amino acid substitution in each protein. An additional 14% of non-BS-PGs had somatic mutations in H3F3A causing a p.Gly34Arg alteration.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•A multi-scale method is proposed to judge the matrix damage at meso scale.•The multi-scale method is combined with void defect analysis.•The effect of void content on the elastic properties of CFRP ...was analyzed.•The effect of void content on the impact properties of CFRP laminates was analyzed.
The void defects produced in the composite material manufacturing process directly affect the basic mechanical properties of Carbon fiber reinforced polymers (CFRP), resulting in weakened impact resistance. This paper combines the advantages of the fast calculation speed of the macro-model and the more accurate micro-model, and proposes a multi-scale method that can judge fiber and matrix damage at the micro-scale. According to this multi-scale method, the representative volume element (RVE) of the unidirectional (UD) carbon fiber was studied, and the relationship between the six elastic properties of the CFRP and the void defects and fiber volume fraction was obtained. It was assumed that the void defects were of the same size and randomly distributed in the matrix, ignoring the effect of void shape. Analyze the impact resistance of CFRP laminates containing void defects, and the relationship between each characteristic parameter and the content of void defects. Exploring the impact resistance of CFRP laminates containing void defects, it is found that under rebound conditions, as the void content increases, the peak force decreases, the maximum displacement and the final energy absorption increase, but they are not linear. Under penetration conditions, the peak force and final energy absorption decrease nonlinearly with the increase void defect content. The innovation of this paper is to combine the multi-scale analysis method and the void defects, and obtain the relationship between the void content and the elastic properties of the CFRP, and apply the CFRP laminate containing the void defects to the impact condition, to explore its impact on impact performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Differential Evolution(DE) is a widely used technique to tackle complex optimization problems owing to its easy-implementation and excellent performance, nevertheless, the inborn weakness of the ...crossover operation has not been solved even in the recent state-of-the-art DE algorithms. There are two commonly used crossover schemes in DE, the exponential crossover and binomial crossover. The exponential crossover is actually a combination of 1-point and 2-point crossover schemes originated with Genetic Algorithm (GA), and it has positional bias because of the dependence on parameter separation. The binomial crossover tackles the positional bias by separating each dimension separately and treating them independently, however, bias still exists from a higher dimensional view, we name it selection bias, and that is the reason why the QUATRE algorithm was proposed. The evolution matrix is the primary component of the QUATRE algorithm which solves the selection bias of DE, however, the previous QUATRE variants still suffer the adaptation of the evolution matrix and can not be able to escape some local optima in complex optimization. Therefore, this paper proposes a new QUATRE with better adaptations of evolution matrix and control parameter, moreover, a perturbation mechanism is firstly proposed for the enhancement of population diversity. The main contributions of our algorithm can be summarized as follows. First, a new generation of evolution matrix is proposed, which can obtain better adaptation to the landscape of the objectives and help the algorithm jump out some local optima. Second, novel adaptations of control parameters are also proposed by incorporating historical memory mechanism and population reduction. Third, a new perturbation mechanism is proposed to enhance the population diversity. In order to validate the proposed algorithm, intensive experiments are conducted under 88 benchmark functions from the universal CEC2013, CEC2014, and CEC2017 test suites in comparison with several excellent DE variants and QUATRE variants, and the results support our superiority.
Diffuse intrinsic pontine gliomas (DIPGs) are incurable childhood brainstem tumors with frequent histone H3 K27M mutations and recurrent alterations in PDGFRA and TP53. We generated genetically ...engineered inducible mice and showed that H3.3 K27M enhanced neural stem cell self-renewal while preserving regional identity. Neonatal induction of H3.3 K27M cooperated with activating platelet-derived growth factor receptor α (PDGFRα) mutant and Trp53 loss to accelerate development of diffuse brainstem gliomas that recapitulated human DIPG gene expression signatures and showed global changes in H3K27 posttranslational modifications, but relatively restricted gene expression changes. Genes upregulated in H3.3 K27M tumors were enriched for those associated with neural development where H3K27me3 loss released the poised state of apparently bivalent promoters, whereas downregulated genes were enriched for those encoding homeodomain transcription factors.
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•H3.3 K27M mutation enhances neural stem cell self-renewal•Neonatal PDGFRα activation and Trp53 loss induces supratentorial and brainstem glioma•H3.3 K27M preferentially accelerates hindbrain tumorigenesis•H3.3 K27M drives bivalent gene activation associated with neurodevelopment in DIPG
Larson et al. show that H3.3 K27M cooperates with active PDGFRα mutant and loss of p53 to induce brainstem gliomas molecularly resembling human DIPG in mice. These tumors show global H3K27 modification but restricted gene expression changes, including upregulation of genes associated with neural development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper studies the modeling method and collaborative optimization of the dynamic responses for barrier-vehicle-occupant (BVO) system in engineering. The mechanical analytical model of BVO system ...is established to obtain not only the system dynamic responses but also the evaluation indexes of crashworthiness and compatibility. A collaborative optimization method that combines the BVO model and genetic algorithm is presented to obtain the optimal crash pulse of vehicle. An empirical case of an existing vehicle that has been in running in China is applied to verify this constructed model and solution method. Compared with the results of original alternative, the peak occupant acceleration and occupant load criterion (
OLC
) of barrier are reduced by 54.65% and 14.07%, respectively, and avoid the barrier bottoming out effectively. In addition, a sensitivity analysis is conducted and the results could be found that the heights about the middle part have a significant impact on occupant injury, OLC, and the middle backward part have a significant impact on the bottoming out of barrier, respectively. In summary, the concave shape crash pulse can improve crashworthiness and compatibility. This research reveals the principles of the BVO system and provides an effective tool to solve the optimization problem in conceptual design of vehicle.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
Pediatric high-grade glioma (pHGG) is a major contributor to cancer-related death in children. In vitro and in vivo disease models reflecting the intimate connection between developmental ...context and pathogenesis of pHGG are essential to advance understanding and identify therapeutic vulnerabilities. Here we report establishment of 21 patient-derived pHGG orthotopic xenograft (PDOX) models and eight matched cell lines from diverse groups of pHGG. These models recapitulate histopathology, DNA methylation signatures, mutations and gene expression patterns of the patient tumors from which they were derived, and include rare subgroups not well-represented by existing models. We deploy 16 new and existing cell lines for high-throughput screening (HTS). In vitro HTS results predict variable in vivo response to PI3K/mTOR and MEK pathway inhibitors. These unique new models and an online interactive data portal for exploration of associated detailed molecular characterization and HTS chemical sensitivity data provide a rich resource for pediatric brain tumor research.
The safe and effective treatment for dyeing wastewater including harmful metal ions, which are important environmental pollution sources, has not been solved in the realistic industry. Using natural ...materials with short regeneration cycle should be valued in recognized and effective adsorption techniques. In this study, hydroxyl-rich tannin molecules were successfully modified on palm leaf sheath fibers (PLSF) to obtain multifunctional adsorbent for simultaneous removal of dye molecules and heavy metal ions in dyeing wastewater. As a result, modified PLSF can effectively adsorb reactive yellow 3 (RY3) dye molecules with a maximum adsorption capacity of 83.19 mg/g from dyeing wastewater, while the sample loaded with RY3 can adsorb Cr(VI) with a maximum adsorption capacity of 189.48 mg/g. XRD, SEM, FT-IR, and stereomicroscope are used to characterize the adsorbent samples. The kinetic and thermodynamic analysis results show that the adsorption of RY3 and Cr(VI) by the adsorbent is consistent with pseudo-second-order kinetics and the Langmuir isotherm model. The thermodynamic parameters of Cr(VI) adsorption indicate that adsorption is a spontaneous endothermic process and has good reusability of Cr(VI).
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Fiber distributions were measured by X-ray computed tomography and implemented into the two-phase modeling.•A power law correlating the absorbed energy and the impact energy was proposed.•The ...expression of minimum penetration energy was derived and applied for quick design of fiber content and thickness.
Impact behavior and energy absorption of long fiber-reinforced thermoplastic (LFT) plates under low velocity impact load is investigated based on two-phase modeling and experiments. In this study, strain rate dependent properties and fiber distribution are characterized by mechanical tests and X-ray CT scans. A two-phase homogenized material model is established and validated by impact test data. On this basis, this paper presents a method for the assessment of the energy absorption capability of LFT plates, which defined as a power law equation normalized by penetration energy. The accuracy and applicability of the proposed approach is validated by finite element simulations of three impactor diameters. The results show a good consistency and indicate that the exponent of the power law is probably independent of the fiber content distributions and impact conditions. The expression of minimum penetration energy is derived and can help in a quick design of fiber volume fraction and plate thickness.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A Fe-Co dual-metal co-doped N containing the carbon composite (FeCo-HNC) was prepared by adjusting the ratio of iron to cobalt as well as the pyrolysis temperature with the assistance of ...functionalized silica template. Fe
Co-HNC, which was formed with 1D carbon nanotubes and 2D carbon nanosheets including a rich mesoporous structure, exhibited outstanding oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activities. The ORR half-wave potential is 0.86 V (vs. reversible hydrogen electrode, RHE), and the OER overpotential is 0.76 V at 10 mA cm
with the Fe
Co-HNC catalyst. It also displayed superior performance in zinc-air batteries. This method provides a promising strategy for the fabrication of efficient transition metal-based carbon catalysts.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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