Powder bed fusion (PBF) process is expeditely moving towards its maturity for the direct manufacturing of intricated and sophisticated metallic parts. The typical process is instead complex and yet ...challenging to interpret experimentally. Modeling and simulation strategy has been widely implemented to comprehend and optimize the process. Therefore, an integrated simulation approach incorporating stochastic powder deposition and subsequently selective melting is developed to understand the consolidation mechanism in a multilayer process of electron beam PBF additive manufacturing. Simulation results of a thin-walled cross section are validated with the published experimental data to demonstrate the effectiveness of the proposed model. The simulation results of the multilayer process revealed that the layer thickness keeps on slight changes until reaching a steady state during the multilayer additive process. The stable powder layer thickness is systematically analyzed, which proved that the influence of the wall effect should be considered in smaller nominal layer thickness and denser powder bed. Finally, the printing quality in the multilayer process is dependent on adequate inter- and intra-layer bonding when the layer thickness reaches its maximum value, where agglomeration and balling effect in melt pool dynamics predominant by surface tension play crucial roles.
Objective
Overexpression of microRNA-21 (miR-21) increases the radiation resistance of esophageal squamous cell carcinoma (ESCC). However, the molecular mechanism responsible for this action is still ...unclear. In the present study, we investigated the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in miR-21-enhanced radiation resistance in patients with ESCC.
Methods
We evaluated the association between miR-21 levels and radiation resistance in patients with ESCC. We also investigated the role of PTEN in the proliferation and apoptosis of ESCC cells transfected with miR-21 inhibitor during irradiation, using PTEN small interfering RNA (siRNA).
Results
MiR-21 levels were significantly higher in radiation-resistant patients. Downregulation of miR-21 during irradiation suppressed the radiation resistance of ESCC cells, demonstrated by decreased cell proliferation and increased cell apoptosis. PTEN siRNA attenuated miR-21-induced suppression of radiation resistance in ESCC cells.
Conclusions
These results suggest that miR-21 enhanced the radiation resistance of ESCC by inhibiting PTEN. MiR-21 and PTEN are potential therapeutic biotargets for ESCC.
•The densification behavior in different hatch distances was investigated.•The microstructure evolution was characterized and analyzed.•The strengthening mechanism was explored.•The relationship ...between microstructure and mechanical properties was established.
Laser powder bed fusion (LPBF) of duplex stainless steel is a promising route to fabricate intricate parts with excellent mechanical properties. However, further understanding of build mechanisms is required to improve the process. This paper aims to better understand the influence of hatch distance on the densification behavior and figure out the correlation with microstructure and mechanical properties in LPBF of 2205 stainless steel. With the optimized laser power and scanning speed, the significant influence of hatch distance on the build quality is revealed. A hatch distance of 0.07 mm is selected for an even surface and dense part with a relative density of up to 99.13 %. The hatch distance has a crucial impact on the heat and mass transfer between tracks; hence, poor surface morphologies such as inter-track voids or swelling surfaces occur if an improper hatch distance is adopted. The optimal mechanical properties are also achieved. Specifically, the yield strength (0.2 YS), ultimate tensile strength (UTS), and elongation (EL) values are 896.8 MPa, 1035.13 MPa, and 15.34 %, respectively. The improvement in mechanical properties can be ascribed to the coordination between high dislocation density, fine grain size, high CSL boundaries and LAGBs, and high relative density with few pores. This work can help improve the build quality and expand the application horizon of duplex stainless steel for manufacturing intricate components.
To provide a detailed analysis of the molecular components and underlying mechanisms associated with ovarian cancer, we performed a comprehensive mass-spectrometry-based proteomic characterization of ...174 ovarian tumors previously analyzed by The Cancer Genome Atlas (TCGA), of which 169 were high-grade serous carcinomas (HGSCs). Integrating our proteomic measurements with the genomic data yielded a number of insights into disease, such as how different copy-number alternations influence the proteome, the proteins associated with chromosomal instability, the sets of signaling pathways that diverse genome rearrangements converge on, and the ones most associated with short overall survival. Specific protein acetylations associated with homologous recombination deficiency suggest a potential means for stratifying patients for therapy. In addition to providing a valuable resource, these findings provide a view of how the somatic genome drives the cancer proteome and associations between protein and post-translational modification levels and clinical outcomes in HGSC.
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•Comprehensive proteomic characterization of 174 ovarian tumors are analyzed•Copy-number alterations affect the proteome in trans, converging on pathways•Acetylation of histone H4 correlates with homologous repair deficiency status•Protein and phosphoprotein abundance identifies pathways associated with survival
Layering proteomic and genomic data from ovarian tumors provides insights into how signaling pathways correspond to specific genome rearrangements and points to the benefit of using protein signatures for assessing prognosis and treatment stratification.
Molybdenum is a newly added material in additive manufacturing material cabinet, and it is under the spotlight owing to its crucial applications. The high-energy electron beam selective melting ...(EBSM) process is supposed to be a promising technique for molybdenum printing because of its vacuum environment. This paper presents EBSM numerical process simulation for molybdenum on macro- and mesoscale established with exclusive powder material modeling. Experimentally determined, process parameters are implemented in 3D macro- and 2D mesoscale models for a profound process insight. Primarily molybdenum powder material model is established, and a multi-track FEM simulation is performed to predict melt pool configuration, temperature field and phase transformation. Next, powder consolidation mechanism, side surface roughness, porosity, and voids are investigated through a CFD model, where the molybdenum particles are explicitly considered from the EBSM process viewpoint. Results proved the effectiveness of the numerical simulation for detailed EBSM process understanding for molybdenum material.
A systematic study on the densification behavior and build quality of 2205 duplex stainless steel fabricated using laser powder bed fusion (LPBF) was performed by experiment and simulation, aiming to ...offer some supplementary work for research on additive manufacturing (AM) of duplex stainless steel. In this study, samples with differing laser powers were prepared, and a highest relative density of 98.87% was obtained. Then, the pore defects and surface morphologies were investigated to unveil densification behaviors during a building process. The relationship between surface morphologies and the formation of pores was discussed. It reveals that the inter-layer printing on these surface defects caused by unreasonable laser power could increase the possibility of inside pore defects and reduce the density of specimens. Particularly, the big spatters could be the cause of lack-of-fusion defects even under sufficient power input. Therefore, adequate intra- and inter-layer bonding under reasonable processing parameters is crucial for densification. The mechanical properties of the specimens prepared with the laser power of 260 W are the highest, and the yield strength, tensile strength, and elongation are 798.68 MPa, 953.63 MPa, and 10.85%, respectively.
In this Letter, a novel filtering power divider with second-order quasi-elliptic bandpass response is proposed, which has two transmission zeros near to the passband for sharp frequency selectivity. ...In addition, it is featured by ultra-wide stopband owing to specific topology. For demonstration, a filtering power divider example operating at 3.1 GHz is designed, fabricated and measured. Its 3 dB fractional bandwidth is about 11.9%, and the in-band isolation between two output ports exceeds 20 dB. Specifically, more than 21 dB out-of-band suppression is achieved from the upper side of the passband to 4.8f0, and more than 12 dB suppression is achieved to at least 20f0. The measurement agrees well with the simulation.
Laser cladding has emerged as a promising technique for custom-built fabrications, remanufacturing, and repair of metallic components. However, frequent melting and solidification in the process ...cause inevitable residual stresses that often lead to geometric discrepancies and deterioration of the end product. The accurate physical interpretation of the powder consolidation process remains challenging. Thermomechanical process simulation has the potential to comprehend the layer-by-layer additive process and subsequent part-scale implications. Nevertheless, computational accuracy and efficacy have been serious concerns so far; therefore, a hybrid FEM scheme is adopted for efficient prediction of the temperature field, residual stress, and distortion in multilayer powder-fed laser cladding of Inconel
718. A transient material deposition with powder material modeling is schematized to replicate the fabrication process. Moreover, simulation results for residual stress and distortion are verified with in-house experiments, where residual stress is measured with XRD (X-Ray Diffraction) and geometric distortion is evaluated with CMM (Coordinate Measuring Machine). A maximum tensile residual stress of 373 ± 5 MPa is found in the vicinity of the layer right in the middle of the substrate and predicted results are precisely validated with experiments. Similarly, a 0.68 ± 0.01 mm distortion is observed with numerical simulation and showed a precise agreement with experimental data for the same geometry and processing conditions. Conclusively, the implemented hybrid FEM approach demonstrated a robust and accurate prediction of transient temperature field, residual stresses, and geometric distortion in the multilayer laser cladding of Inconel
718.
Little is known about how chronic inflammation contributes to the progression of hepatocellular carcinoma (HCC), especially the initiation of cancer. To uncover the critical transition from chronic ...inflammation to HCC and the molecular mechanisms at a network level, we analyzed the time-series proteomic data of woodchuck hepatitis virus/c-myc mice and age-matched wt-C57BL/6 mice using our dynamical network biomarker (DNB) model. DNB analysis indicated that the 5th month after birth of transgenic mice was the critical period of cancer initiation, just before the critical transition, which is consistent with clinical symptoms. Meanwhile, the DNB-associated network showed a drastic inversion of protein expression and coexpression levels before and after the critical transition. Two members of DNB, PLA2G6 and CYP2C44, along with their associated differentially expressed proteins, were found to induce dysfunction of arachidonic acid metabolism, further activate inflammatory responses through inflammatory mediator regulation of transient receptor potential channels, and finally lead to impairments of liver detoxification and malignant transition to cancer. As a c-Myc target, PLA2G6 positively correlated with c-Myc in expression, showing a trend from decreasing to increasing during carcinogenesis, with the minimal point at the critical transition or tipping point. Such trend of homologous PLA2G6 and c-Myc was also observed during human hepatocarcinogenesis, with the minimal point at high-grade dysplastic nodules (a stage just before the carcinogenesis). Our study implies that PLA2G6 might function as an oncogene like famous c-Myc during hepatocarcinogenesis, while downregulation of PLA2G6 and c-Myc could be a warning signal indicating imminent carcinogenesis.
This study aims to investigate the serum fat-soluble vitamins A, D, and E levels of children in Zhejiang Province, and to provide a reference range of fat-soluble vitamins for children in Zhejiang ...Province.
Between May 2019 and December 2019, 871 children who sent peripheral blood samples to Hangzhou Biozon Medical Institute Co., Ltd. for fat-soluble vitamin A, D, and E analysis were selected, including 432 boys and 439 girls. After the peripheral blood was collected, the serum A, D, and E levels were measured, and the differences in age, gender, season, and region were compared.
With age, the level of vitamin A gradually increased (p < 0.01), and vitamin D2, D3, and total vitamin D all increased first and then decreased. Vitamin A (131.79 ± 47.05 ng/mL vs. 121.96 ± 41.01 ng/mL) and E (5.87 ± 2.23 μg/mL vs. 5.56 ± 2.13 μg/mL) levels of girls were higher than boys (p < 0.01), and vitamin D3 (15.25 ± 6.16 ng/mL vs.15.17 ± 7.26 ng/mL) and total vitamin D (18.09 ± 7.01 ng/mL vs. 17.03 ± 8.79 ng/mL) levels of boys were higher than girls (p < 0.01). From the perspective of regional distribution, the levels of vitamin A, D2, and E in Ningbo were higher than those in Hangzhou and other regions. The seasonal distribution of vitamin A and E levels were highest in summer, while vitamin D3 and D levels were highest in fall. The average vitamin concentrations were as follows: vitamin A was (126.81 ± 44.42) ng/mL; vitamin D2 was (1.84 ± 3.16) ng/mL, vitamin D3 was (15.71 ± 6.75) ng/mL, total vitamin D was (17.55 ± 7.91) ng/mL, and vitamin E was (5.72 ± 2.19) μg/mL. The reference value ranges of vitamin A, D2, D3, D, and E were (52.44 - 222.27) ng/mL, (0.01 - 11.66) ng/mL, (4.92 - 30.96) ng/mL, (4.92 - 30.96) ng/mL, and (2.66 - 10.92) μg/mL, respectively.
The childrens' fat soluble vitamin levels in Zhejiang province show significant differences in age, gender, season, and regional distribution. Corresponding reference standards should be formulated as soon as possible, and vitamin supplements should be targeted and reasonable to ensure the healthy development of children.
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