Micro-grinding has a wide application for machining meso/micro parts using hard and brittle materials with high precision. In order to investigate the effect of grinding parameters and various ...micro-grinding tools on micro-grinding quality, experimental trials on side grinding of single crystal silicon (100 lattice orientation) were carried out using electroplated diamond micro-grinding tools. Based on experimental results, the effects of grinding parameters involving spindle speed, grinding depth and feed rate, together with various micro-grinding tools including different grain size and tip diameter on micro-grinding quality were discussed. The micro-grinding quality was mainly evaluated in terms of surface roughness and the average edge-chipping width. The wear condition of micro-grinding tools under different tip diameter and grain size was analyzed. In addition, the effect of tool wear on micro-grinding quality was also discussed. From the experimental results, feed rate showed significant effect on micro-grinding quality. The wear of micro-grinding tools could be divided into initially fast wear stage and steady wear stage, which was crucial to influence the grinding quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Hepatocellular carcinoma (HCC) is widely recognized for its unfavorable prognosis. Increasing evidence has revealed that LGALS3 has an essential function in initiating and developing several ...malignancies in humans. Nevertheless, thorough analysis of the expression profile, clinical prognosis, pathway prediction, and immune infiltration of LGALS3 has not been fully explored in HCC.
In this study, an initial pan-cancer analysis was conducted to investigate the expression and prognosis of LGALS3. Following a comprehensive analysis, which included expression analysis and correlation analysis, noncoding RNAs that contribute to the overexpression of LGALS3 were subsequently identified. This identification was further validated using HCC clinical tissue samples. TIMER2 and GEPIA2 were employed to examine the correlation between LGALS3 and HCP5 with immunological checkpoints, cell chemotaxis, and immune infiltration in HCC. The R program was applied to analyze the expression distribution of immune score in in HCC patients with high and low LGALS3 expression. The expression profiles of immune checkpoints were also analyzed. Use R to perform GSVA analysis in order to explore potential signaling pathways.
First, we conducted pan-cancer analysis for LGALS3 expression level through an in-depth analysis of public databases and found that HCC has a high LGALS3 gene and protein expression level, which were then verified in clinical HCC specimens. Meanwhile, high LGALS3 gene expression is related to malignant progression and poor prognosis of HCC. Univariate and multivariate analyses confirmed that LGALS3 could serve as an independent prognostic marker for HCC. Next, by combining comprehensive analysis and validation on HCC clinical tissue samples, we hypothesize that the HCP5/hsa-miR-27b-3p axis could serve as the most promising LGALS3 regulation mechanism in HCC. KEGG and GO analyses highlighted that the LGALS3-related genes were involved in tumor immunity. Furthermore, we detected a significant positive association between LGALS3 and HCP5 with immunological checkpoints, cell chemotaxis, and immune infiltration. In addition, high LGALS3 expression groups had significantly higher immune cell scores and immune checkpoint expression levels. Finally, GSVA analysis was performed to predict potential signaling pathways linked to LGALS3 and HCP5 in immune evasion and metabolic reprogramming of HCC.
Our findings indicated that the upregulation of LGALS3 via the HCP5/hsa-miR-27b-3p axis is associated with unfavorable prognosis and increased tumor immune infiltration in HCC.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
We theoretically demonstrate a Dirac fermion metagrating which is an artificially engineered material in graphene. Although its physics mechanism is different from that of optical ...metagrating, both of them can deliver waves to one desired diffraction order. Here we design the metagrating as a linear array of bias-tunable quantum dots to engineer electron beams to travel along the -1st-order transmission direction with unity efficiency. Equivalently, electron waves are deflected by an arbitrary large-angle ranging from 90° to 180° by controlling the bias. The propagation direction changes abruptly without the necessity of a large transition distance. This effect is irrelevant to complete band gaps and thus the advantages of graphene with high mobility are not destroyed. This can be attributed to the whispering-gallery modes, which evolve with the angle of incidence to completely suppress the other diffraction orders supported by the metagrating and produce unity-efficiency beam deflection by enhancing the -1st transmitted diffraction order. The concept of Dirac fermion metagratings opens up a new paradigm in electron beam steering and could be applied to achieve two-dimensional electronic holography.
The application of hard and brittle materials such as single-crystal silicon in small parts has expanded sharply, and the requirements for their dimensional accuracy and processing surface quality ...have been continuously improved. This paper proposes using mechano-chemical micro-grinding tools to process single-crystal silicon, which can realize the high-quality and efficient processing of such tiny parts through mechano-chemical composite action. The microstructure composition of the mechano-chemical micro-grinding tools was designed, the theoretical analysis model of grinding force was established and verified by experiments, and the temperature field distribution during mechano-chemical micro-grinding of single-crystal silicon was simulated and studied, which provided a theoretical basis for mechano-chemical action. Special micro-grinding tools were developed, and mechano-chemical micro-grinding processing tests were carried out. The results show that the coupling synergy of grinding force and grinding temperature improves the chemical activity of the micro-grinding tools, thereby promoting the solid–solid phase chemical reaction of abrasives and additives at the sharp points of the surface of the micro-grinding tools. And when the content of cerium oxide abrasive is 25%, it is more conducive to the solid–solid phase chemical reaction, and calcium oxide can be used as an additive to promote the active agent of solid–solid phase chemical reaction, improve the degree of chemical reaction, and thus improve the removal rate of materials. Soft reactants that are easy to remove are generated on the surface of monocrystalline silicon and are removed by the mechanical friction between the abrasive grain and the surface of the silicon wafer, and finally achieve low-damage processing with a surface roughness of Ra1.332 nm, which is much better than the surface roughness of Ra96.363 nm after diamond abrasive processing.
For high performance manufacturing of micro parts and features, a hybrid chemical modification strategy is proposed to decrease critical energy barrier of mechanical removal of hard and brittle ...crystal material by refining localized machining condition. The strategy, namely UV-light and IR-laser hybrid chemical modification (UVIR-CM) strategy, includes two steps, an ultraviolet light (UV-light) catalytic advanced oxidation and an infrared laser (IR-laser) assisted selective modification based on Fenton liquid–solid reaction for monocrystalline silicon. The modification effects of UVIR-CM strategy were investigated by surface morphology micro-observation, cross-section transmission electron microscopy (TEM) observation, Raman spectroscopy analysis and nanoindentation test. Experimental results demonstrated that varied degrees of laser texturing appeared on different strategy samples’ IR-laser scanned area. And the IR-laser thermal damage has been successfully inhibited due to the refraction and reflection of energy by bubbles in liquid medium. But for the UVIR-CM strategy, a uniform and amorphous silicate layer is detected in a certain boundary. The UV-light promotes oxidation cycle ability of the chemical solution and ensures sufficient oxide modified layer for subsequent step. Attributing to synergism of photochemical, photothermal and kinetic effects induced by IR-laser, the modified layer displays layered structure with about 600 nm thickness, (2.7 ± 0.60) GPa nanohardness, and (93.7 ± 22.9) GPa indentation modulus. And the layered structure is amorphous layer, nanocrystal and micro-twins layer from the surface to the interior of sample. Consequently, it reveals that the subsequent mechanical removal will become easy due to decreasing energy barrier of monocrystalline silicon in selective area. Meanwhile, its original excellent mechanical properties also are maintained under a certain depth. The results contribute to develop a novel combined micro-machining technology to achieve collaborative manufacturing of structure shape and surface integrity for micro parts and feature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Cortical bone is semi-brittle and anisotropic, that brings a challenge to suppress vibration and avoid undesired fracture in precise cutting process in surgeries. In this paper, a novel analytical ...model is proposed to represent cortical bone cutting processes. The model is utilized to predict the chip formations, material removal behavior and cracks propagation under varying bone osteon cutting angles and depths. Series of orthogonal cutting experiments were conducted on cortical bone to investigate the impact of bone osteon cutting angle and depth of cut on cutting force, crack initialization and propagation. The observed chip morphology highly agreed with the prediction of chip formation based on the analytical model. The curly, serrated, grainy and powdery chips formed when the cutting angle was set as 0°, 60°, 90°, and 120°, respectively. Cortical bone were removed dominantly by shearing at a small depth of cut from 10 to 50 μm, and by a mixture of pealing, shearing, fracture and crushing at a large depth of cut over 100 μm at different bone osteon angles. Moreover, its fracture toughness was calculated based on measured cutting force. It is found that the fluctuation of cutting force is suppressed and the bone material becomes easy to remove, which attributes to lower fracture toughness at bone osteon cutting angle 0°. When the cutting direction develops a certain angle to bone osteon, the fracture toughness increases then the crack propagation is inhibited to some extent and the fluctuation of cutting force comparatively decreases. There is a theoretical and practical significance for tools design and operational parameters choice in surgeries.
The grind-hardening process utilizes the heat generated to induce martensitic phase transformation. However, the maximum achievable harden layer depth is limited due to high grinding forces, and the ...tensile residual stress appears on the ground surface in the grind-hardening process. This paper proposes a new grind-hardening technology using thermal compensation. The workpiece of AISI5140 steel is preheated by electric resistance heating, and ground under the condition of the workpiece temperature 25°C, 120°C, 180°C and 240°C. The grinding force, harden layer depth and surface quality including residual stress on ground surface, surface roughness and micro-hardness are investigated. The experimental results show that a deep harden layer with a fine grain martensite can be obtained with the thermal compensation. The ground workpiece surface produces a certain compressive residual stress, and the residual compressive stress value increases with preheating temperature. As the preheating temperature increases, grinding force slightly decreases, while there is slightly increment of surface roughness. Compared with the conventional grind-hardening process, both the harden layer depth and residual stress distribution are significantly improved.
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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
Cancer-associated fibroblasts (CAFs) are major component of tumor microenvironment (TME), which plays crucial roles in tumor growth, invasion and metastasis; however, the underling mechanism is not ...fully elucidated. Despite many studies are focused on the tumor promoting effect of CAFs-derived cytokines, the upstream regulators of cytokine release in CAFs is largely unknown. Here we found that miR-101-3p was downregulated in primary lung cancer-associated CAFs compared to normal fibroblasts (NFs). Ectopic overexpression of miR-101-3p suppressed CAFs activation, and abrogated the promoting effect of CAFs on migration and invasion of non-small cell lung cancer cells (NSCLC), through attenuating CAFs' effect on epithelial mesenchymal transition (EMT) process, metastasis-related genes (MMP9, TWIST1) and AKT/endothelial nitric oxide synthase (eNOS) signaling pathway. Further study indicated that vascular endothelial growth factor A (VEGFA) was a novel target of miR-101-3p, and CAFs-derived VEGFA mediated the effect of miR-101-3p on migration and invasion of lung cancer cells, demonstrated by using recombinant VEGFA and VEGFA neutralizing antibody. Interestingly, the analysis of the Cancer Genome Atlas (TCGA) database revealed that lung cancer tissues expressed lower level of miR-101-3p than non-cancerous tissues, and low/medium-expression of miR-101-3p was associated with poor overall survival (OS) rate. Moreover, the mouse xenograft experiment also showed that CAFs accelerated tumor growth whereas miR-101-3p diminished CAFs' effect. These findings revealed a novel mechanism that CAFs facilitated lung cancer metastasis potential
miR-101-3p/VEGFA/AKT signaling pathway, suggesting miR-101-3p as a potential candidate for metastasis therapy.
Wide-band-gap semiconductors such as silicon carbide, gallium nitride, and diamond are known as hard-to-process materials. In this study, two types of chemical mechanical polishing (CMP)-related ...processing equipment were designed to create novel high-efficiency and high-quality processing technology for these crystal substrates. Applying these apparatuses, the processing mechanisms are discussed and the processing characteristics of the hard-to-process substrates investigated. The two types of prototype processing equipment were the closed chamber-type processing environment control CMP equipment and the plasma fusion CMP equipment. In the former, high-efficiency processing was attempted by introducing a photocatalytic reaction while adding ultraviolet (UV) irradiation to a high-pressure oxygen atmosphere. In the latter, we expected a synergistic effect that could bring out the features of atmospheric pressure plasma chemical vaporization machining (P-CVM) and CMP, especially with a diamond substrate that is very hard and chemically stable. When the processing mechanisms of these equipment were examined, the processing was promoted while forming reaction products such as hydrated and oxide films on the extreme surface. Therefore, the chamber-type CMP equipment by UV irradiation was particularly effective in a high-pressure oxygen environment. In the plasma fusion CMP equipment, high-efficiency processing of the diamond substrate was possible when P-CVM and CMP were simultaneously operated in an oxygen atmosphere. Furthermore, based on the studied processing mechanism, a "cyclic processing method" consisting of two steps, a pseudo radical field / reaction product formation step and a new surface contact magnetorheological finishing step, was proposed as a highly efficient processing process.
Although various achievements were made in past years to improve the mechanism of cystallization of metallic glass using annealing or deformation processes, the relationship between the ...micromechanisms of nanocrystalline formation in metallic glass while milling has not been thoroughly investigated. To elaborate on the connection between plastic deformation, stress, temperature, and nanocrystallization, the laminated Fe-based metallic glass foil (FMGF) was machined by side-milling with and without ultrasonic vibration. Plastic deformation can accelerate nucleation and therefore nanocrystallization with respect to phase separation in FMGF at high temperatures. The nanocrystal distributions in the FMGF milled with ultrasonic vibration is cyclical along the milling direction. The temperature of the nucleation and growth mechanism associated with phase separation is higher than that of the nucleation mechanism based on the linked-flus model. The results provide insights on the effects of plastic deformation and high temperature in the crystallization of FMGF.
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•Plastic deformation can accelerate nanocrystallization with the nucleation and growth mechanism with phase separation.•The nanocrystals distribution in the FMGF milled with ultrasonic vibration is cyclical along the milling direction.•The temperature of the mechanism with phase separation is higher than that of the mechanism based on the linked-flus model.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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