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In concentration gradient (CG) nano-polycrystalline Ni-Co alloy, the deformation mechanism of each region is different with the increase of Co content. It is found that in the Co-free region, grain boundary diffusion and dislocation slip mechanisms are dominant, while in other regions, there is a synergistic effect of solid solution strengthening. Moreover, the formation of new small grains by the migration of GB atoms will assist in the deformation of large grains, and the alloy exhibits gentle and stable stress–strain curve pattern. Meantime, although the dislocation density of each region is different, the dislocation density still changes stably before and after shearing. Compared with the uniform structure, the flow stress fluctuation is small when the CG structure is plastically deformed, which proves that this kind of structure is more stable. Moreover, it is found that at different temperatures, the CG alloy also shows stable dislocation density and coordination of various mechanisms, which ensures the strength stability. It is revealed that the CG structure has important properties that make the material strength more stable. This work demonstrates the excellent properties of CG alloy and has positive guiding significance for the development of low-cost, high-performance materials in terms of theoretical and practical applications. [ABSTRACT FROM AUTHOR]

Carbon nanorings (CNRs) and carbon nanobelts (CNBs) of various sizes and innovative molecular architectures have ushered improvement in research in recent years. This serves as a prerequisite for further advances and applications, such as organic semiconductors and bottom‐up synthesis of single‐walled carbon nanotubes. Nevertheless, challenges such as high strain energy, excessive reactivity, end‐product stability, low‐scale yields, and side reactions inhibit material synthesis and applications. In this review, CNRs, CNBs, and other heteroatom‐doped molecular belts are discussed based on their molecular structural characteristics, with a special focus on their developments in the past two years. Furthermore, current applications, research obstacles, and future developments related to CNRs and CNBs are discussed. For the first time, studies and advancements in organic field‐effect transistors (OFETs) have been summarized in detail. [ABSTRACT FROM AUTHOR]

The electronic structure and photocatalytic performance of GaSe/MoSSe and Ga2SSe/MoS2 heterojunctions are systematically investigated by means of first-principles calculations. The outcomes demonstrate that the IV and II stacking patterns feature the lowest binding energies and the shortest interlayer spacing, wherein the A stacking configurations show typical type-II band alignment characteristics which are conducive to fulfill effective separation of electron–hole pairs in space. The electrostatic potential and the CDD indicate the generation of built-in electric fields from MoSSe to GaSe layers and from Ga2SSe to MoS2 layers, respectively, in the interfacial domain, providing a theoretical basis for the examination of the photocatalytic mechanism. The two heterojunctions are more preferable for the photocatalytic decomposition of water under acidic and neutral atmospheres at dissimilar pH levels. For the GaSe/MoSSe heterojunction, the band gap follows a monotonic decreasing tendency when the tensile strain increases from 0% to 6%, while in the case of compressive strain, the band gap increases and then decreases, and the heterojunction cannot undertake the water oxidation process when the tensile strain surpasses 2%. Meanwhile, when a compressive strain of 0% to 3% is imposed, the heterojunction redox potential always traverses the redox potential of water, wherein the photocatalytic performance is sustained. For the Ga2SSe/MoS2 system, the band gap value decreases monotonically with the exertion of both tensile and compressive strains. Moreover, it is applicable to photocatalytic water decomposition in the strain range of −6% to 6%. The absorption coefficients reveal that the two heterojunction system has a higher peak in the visible range than the corresponding monolayer, indicating a higher light absorption intensity. Furthermore, the electron mobility of heterojunctions along both directions is significantly higher than that of MoS2 and WSe2 monolayers, and GaSe/HfS2 and K2Se/Cs2S heterojunctions. These findings propose that both GaSe/MoSSe and Ga2SSe/MoS2 heterojunctions can be utilized as potentially better catalysts for the photocatalytic decomposition of water. [ABSTRACT FROM AUTHOR]

Bile reflux (BR) was considered to be an independent risk factor for the development of precancerous gastric lesions and GC. Dendrobium officinale polysaccharides (DOP) show a novel potential in preventing the progress of gastric cancer. However, the specific mechanism of DOP that causes such activities remains a mystery. This study aimed to investigate the effects of DOP on chenodeoxycholic acid (CDCA)-induced gastric intestinal metaplasia and explore the underlying mechanisms. Different concentrations of DOP had no significant damage to normal GSE-1 cells and gastric intestinal metaplasia model cells by CCK-8 assay. After DOP treatment, the mRNA and protein expression of CDX2 (p < 0.01) and HNF4α (p < 0.01) were decreased, and HO-1 (p < 0.05) and TFF2 (p < 0.01) were increased. The NRF2 protein expression was slightly upregulated (p < 0.05), and H-DOP further promoted NRF2 protein expression in the nucleus (p < 0.05). Hence, our findings reveal that DOP could be used as a potential anti-inflammation supplement by activating NRF2/HO-1 and modulating the HNF4α/CDX2 signaling pathway to inhibit the progress of CDCA-induced gastric intestinal metaplasia. [ABSTRACT FROM AUTHOR]

Grain boundary engineering is an effective and feasible metal strengthening strategy to enhance the properties of nanopolycrystalline alloys by changing the number, configuration, and connectivity of different types of grain boundaries, especially for the twin boundaries. In the present contribution, the effect of twin spacing and loading mode on the deformation behavior and mechanism of NiCoAl columnar polycrystalline alloy is investigated. The results show that the nanotwins can not only increase the bearing capacity of dislocations but also emit many dislocations, resulting in the coupling effect of dislocation strengthening and twin strengthening. When the twin spacing is large, intrinsic stacking faults occur and gradually transform into deformation twins. In this stage, Shockley partial dislocation controls plastic deformation. When the twin spacing is small, the high‐density twin layers and stacking faults are more likely to interweave, showing a combination action of Shockley partial dislocation and stair‐rod dislocation. With the loading changing to Z axis, the yield strength decreases due to reduced resistance to the dislocation and a weakened number of Shockley partial dislocations of the emission, leading to less strengthening of the twins. The insights provide a solid theoretical foundation for the further application of NiCoAl in industrial production. [ABSTRACT FROM AUTHOR]

Valencene is a natural sesquiterpene with desirable bioactivity and aroma, making it a valuable ingredient in the food and cosmetics industries. Traditionally, valencene was extracted from the citrus fruits, and its applications were restricted by the low concentrations in natural sources and high costs for extraction. Photosynthetic biomanufacturing represents a promising route for efficient and stable production of valencene, while cyanobacteria have been considered one of the most promising platforms regarding biotechnological routes for the direct conversion of CO2. In this work, we engineered Synechocystis sp. PCC 6803 to synthesize valencene. By introducing a heterologous valencene synthase and modifying the native MEP pathway, we obtained an efficient cyanobacterial cell factory that produced 154 mg/L valencene during a semi‐continual cultivation, with an average productivity of 4.3 mg/L/day, and the cell factory exhibited robust growth and production in non‐sterilized conditions. We also achieved the production of other sesquiterpenes including bisabolene, amorpha‐4,11‐diene, farnesene, and nerolidol by engineered cyanobacteria with enhanced MEP pathway flux, showing promising potentials as a universal chassis. [ABSTRACT FROM AUTHOR]