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The corrosion–wear coupling damage failure of 8Cr4Mo4V bearing steel under marine atmospheric conditions significantly limits aeroengine bearing applications. The present work aims to investigate the evolution of the corrosion–wear properties of 8Cr4Mo4V bearing steel at varied corrosion intervals and estimate the corrosion–wear interaction (CWI) effect. Neutral salt spray tests combined with tribological experiments were employed to explore the effect of corrosion on wear and the influence of wear on corrosion, and a quantitative characterization method of corrosion–wear interactions was proposed by establishing the component relationships of material losses in the corrosion–wear process. The results indicate that the corrosion rates initially increase and then decrease, ultimately resulting in a pattern characterized by predominant total corrosion and nested localized corrosion. The corroded surfaces tremendously influence the friction coefficient curves at the third stage, and a synergistic acceleration effect exists in the CWI behavior of 8Cr4Mo4V bearing steel under the action of corrosion and wear. A sample corroded for 6 h displayed the significant facilitative effect of corrosion on wear, exhibiting the highest CWI ratio and a greater total mass loss primarily attributed to corrosion. This study offers a significant reference for the quantitative assessment of the tribo-corrosion properties of bearings in a marine atmospheric environment. [ABSTRACT FROM AUTHOR]

MpaG' is an S‐adenosyl‐L‐methionine (SAM)‐dependent methyltransferase involved in the compartmentalized biosynthesis of mycophenolic acid (MPA), a first‐line immunosuppressive drug for organ transplantations and autoimmune diseases. MpaG' catalyzes the 5‐O‐methylation of three precursors in MPA biosynthesis including demethylmycophenolic acid (DMMPA), 4‐farnesyl‐3,5‐dihydroxy‐6‐methylphthalide (FDHMP), and an intermediate containing three fewer carbon atoms compared to FDHMP (FDHMP‐3C) with different catalytic efficiencies. Here, we report the crystal structures of S‐adenosyl‐L‐homocysteine (SAH)/DMMPA‐bound MpaG', SAH/FDHMP‐3C‐bound MpaG', and SAH/FDHMP‐bound MpaG' to understand the catalytic mechanism of MpaG' and structural basis for its substrate flexibility. Structural and biochemical analyses reveal that MpaG' utilizes the catalytic dyad H306‐E362 to deprotonate the C5 hydroxyl group of the substrates for the following methylation. The three substrates with differently modified farnesyl moieties are well accommodated in a large semi‐open substrate binding pocket with the orientation of their phthalide moiety almost identical. Based on the structure‐directed mutagenesis, a single mutant MpaG'Q267A is engineered with significantly improved catalytic efficiency for all three substrates. This study expands the mechanistic understanding and the pocket engineering strategy for O‐methyltransferases involved in fungal natural product biosynthesis. Our research also highlights the potential of O‐methyltransferases to modify diverse substrates by protein design and engineering. [ABSTRACT FROM AUTHOR]

Cellular pyroptosis is a pro-inflammatory mode of programmed cell death that has been identified in recent years, and studies have shown that the LncRNA SOX2OT regulates myocardial injury during sepsis, but the exact regulatory mechanism is unclear. The aim of this study was to assess the role of SOX2OT in regulating cardiomyocyte injury during sepsis cardiomyopathy. Methods: Rat cardiomyocytes, C57BL/6 mice, and transgenic mice were divided into four groups: control, LPS, LPS+ knockout LncRNA SOX2OT, and LPS+ overexpression LncRNA SOX2OT. Inflammatory factor levels were detected by qPCR. Associated proteins and gene expression were detected by Western blotting and qPCR. Dual luciferase was used to detect the target genes of SOX2OT. Nrf2 and EZH2 knockdown and overexpression cell lines were established, and the expression of related genes was detected by qPCR. Results: Results In this study, we found that SOX2OT knockdown exacerbated LPS-induced levels of inflammatory factors and procalcitoninogen (PCT), and increased the expression of pyroptosis-related proteins and LDH. The results of dual luciferase reporter gene assay showed that EZH2 is the target gene of SOX2OT, and overexpression of SOX2OT decreased the expression of EZH2; we also found that knockdown of EZH2 in H9c2 cells decreased the expression of Nrf2, which was positively correlated with the expression level of NLRP3. Further in vivo results showed that overexpression of SOX2OT attenuated SIMD (sepsis-induced myocardial dysfunction), as evidenced by improved myocardial structural integrity and reduced inflammatory cell infiltration. The expression of pyroptosis-related proteins and LDH was significantly increased in the mice in the LPS group; this effect was reversed by overexpression of SOX2OT, and potentiated by knockdown of SOX2OT. Conclusion: Our data reveal a novel mechanism by which SOX2OT inhibits cardiomyocyte sepsis through the EZH2/Nrf-2/NLRP3 pathway, thereby attenuating septic myocardial injury, which may contribute to the development of new therapeutic strategies. [ABSTRACT FROM AUTHOR]

This study explores gate-controlled superconductivity in metallic superconductors by employing a top-gate architecture with a 15 nm monocrystalline h-BN as a gate dielectric. The transport properties under gate voltage can be elucidated by injecting high-energy electrons, following the Fowler–Nordheim electron field emission model. In contrast to conventional resistive Joule heating, high-energy electron injection with top-gating exhibits excellent power efficiency in suppressing superconductivity. A nearby superconducting bridge, which serves as a thermometer, indicates that our top-gate device can achieve good local control, well limited within a distance of 0.6 μm due to the very low top-gating power. These findings are essential for advancing efficient and highly integrated tunable superconducting electronic devices. [ABSTRACT FROM AUTHOR]

The transverse resistivity anomaly with a hump feature, associated with topological magnetic textures, is of paramount importance for the applications of next-generation chiral spintronic devices. However, the origin of the hump feature still remains debated due to the complicated mechanism, not merely assigned to the intrinsic topological Hall effect (THE). In this work, we observe the apparent transverse resistivity hump characteristic superimposed on the Hall signals in AgNbO3/SrRuO3 (ANO/SRO) heterostructures. The intrinsic THE is ruled out by minor-loop and current density measurements. Combining the microscopic characterization and the two-channel anomalous Hall effect fitting, the hump feature is unambiguously attributed to the synergetic contribution from the SRO layer and the interfacial intermixing thin layer of ANO and SRO. [ABSTRACT FROM AUTHOR]

In this research, high-performance ZnAl-layered double hydroxides (ZnAl-LDHs) with different Zn2+ concentrations were prepared on the surface of an anodized 1060 aluminum alloy using the in situ growth method, and the influence of Zn2+ concentration on corrosion resistance and tribological behavior was further explored. The surface morphology, element distribution, phase composition, and mechanical performance of ZnAl-LDHs/anodic aluminum oxide (AAO) composite coatings were tested and analyzed. Subsequently, the investigation of the anti-corrosion properties and tribological behavior of as-prepared composite coatings and AAO were conducted experimentally. The results show that with the increase in Zn2+ concentration, the thickness and bonding strength of the coatings gradually increase, and the hardness progressively decreases. The ZnAl-LDHs/AAO composite coating with a Zn2+ concentration of 0.3 mol/L exhibits the best anti-corrosion ability, which has the minimum corrosion current density of 2.435 × 10−9 A/cm2. This can be attributed to the uniform and compact ZnAl-LDH films where the porous structure of the AAO is well sealed. Moreover, the excellent friction-reduction and anti-wear properties of ZnAl-LDHs/AAO composite coatings with larger Zn2+ concentrations are verified using a ball-on-disc rotating wear tester under dry wear. A reasonable mechanism for improving tribological properties of resulting ZnAl-LDHs/AAO composite coatings is proposed. [ABSTRACT FROM AUTHOR]

The topological Hall effect (THE) is critical to the exploration of the spin chirality generated by the real‐space Berry curvature, which has attracted worldwide attention for its prospective applications in spintronic devices. However, the prominent THE remains elusive at room temperature, which severely restricts the practical integration of chiral spin textures. Here, a colossal intrinsic THE is showed up to ≈1.6 µΩ cm in large‐area ferromagnet Cr5Te6 thin films epitaxially grown by pulsed laser deposition. Such a THE can be maintained until 270 K, which is attributed to the field‐stimulated noncoplanar spin textures induced by the interaction of the in‐plane ferromagnet and antiferromagnet infrastructures. The first‐principles calculations further verify the considerable Dzyaloshinskii‐Moriya interaction in Cr5Te6. This work not only paves the way for robust chiral spin textures near room temperature in large‐area low‐dimensional ferromagnetic films for practical applications, but also facilitates the development of high‐density and dissipationless spintronic devices. [ABSTRACT FROM AUTHOR]