In this paper, liquid–liquid chromatography was introduced for the first time for the separation of fingered citron (Citrus medica L. var. sarcodactylis Swingle). The fingered citron cultivated in Jinhua is of significant industrial and medicinal value, with several major coumarin compounds detected in its extract. Therefore, further separation for higher purity was of necessity. A preparative liquid–liquid chromatographic method was developed by combining two elution modes (isocratic and step-gradient) with selection according to different polarities of the target sample. Five coumarin derivatives—5,7-dimethoxycoumarin (52.6 mg, 99.6%), phellopterin (4.9 mg, 97.1%), 5-prenyloxy-7-methoxycoumarin (6.7 mg, 98.7%), 6-hydroxy-7-methoxycoumarin (7.1 mg, 82.2%), and byakangelicol (10.5 mg, 90.1%)—with similar structures and properties were isolated on a large scale from 100 mg of petroleum ether (PE) extract and 100 mg of ethyl acetate (EA) extract in Jinhua fingered citron. The productivity was much improved. The anti-growth activity of the isolated coumarins was evaluated against three cancer cell lines (HeLa, A549, and MCF7) with an MTT assay. The coumarins demonstrated potential anti-tumor activity on the HeLa cell line, with 5,7-dimethoxycoumarin in particular exhibiting the best anti-growth activity (IC₅₀ = 10.57 ± 0.24 μM) by inhibiting proliferation. It inhibited colony formation and reduced the size of the tumor sphere in a concentration-dependent manner. The main mechanism was confirmed as inducing apoptosis. This work was informative for further studies aimed at exploring new natural-product-based antitumor agents.

The present study proposes a novel method, i.e., combined severe shot peening (SP) and reversion annealing treatment, to grain-refine the surface layers of 304L austenitic stainless steel. Steel specimens were shot-peened at 0.7 MPa for 30 min, introducing 40% vol. α′ martensite, and then were annealed at 700 or 800 °C for different durations (30 s). As annealing reversed α′ martensite to austenite, the obtained surface layers consist of fully austenitic ultrafine grains. The smallest grain size obtained is about 500 nm at the top surface. SP elevates the microhardness to more than 500 HV. Although the grain-refined surface layers produced by the combined method are not as hard as that treated by only SP, they are harder (e.g., the specimen annealed at 700 °C for 30 s using a heating rate of 50 °C/s exhibited a peak microhardness of 400 HV) than the untreated surface layer (225 HV) due to grain refinement. Moreover, due to the absence of α′ martensite, they have higher corrosion resistance in H₂SO₄ solution than that treated by only SP.

In this study, we investigate the crystal structure, surface energy, and atomic arrangement of Cu₂O. Understanding these properties is crucial for exploring the potential applications and understanding the behavior of this material. We employ the Wulff construction method and an artificial neural network (ANN) model to analyze the relative surface energies of different crystal facets and predict the surface energy of Cu₂O. The ANN model exhibits excellent performance, demonstrating its effectiveness in predicting material properties and providing automated feature-learning and nonlinear-modeling capabilities. Moreover, we analyze the atomic arrangements on various crystal facets and observe the presence of oxygen atoms on the {100} facet, as well as exposed under-coordinated copper atoms on the {111} and {110} facets. High-index facets such as {211} exhibit a higher atomic step density and screw dislocation density. By precisely controlling the synthesis process, it is possible to manipulate the proportion of high-index facets. These findings highlight the significance of understanding the surface energy and atomic arrangement of Cu₂O crystals for comprehending their properties and surface reactions. In summary, this study provides valuable insights into the crystal structure, surface energy, and atomic arrangement of Cu₂O, offering inspiration for its properties and potential applications. The combination of the Wulff construction method and ANN modeling provides a comprehensive understanding of Cu₂O crystals and their surface behavior, contributing to the field of materials science and laying the foundation for various future applications utilizing the unique properties of Cu₂O.

To enhance the corrosion resistance, adhesion strength, and electrical conductivity of bipolar plates for proton exchange membrane fuel cells (PEMFCs), a duplex surface treatment comprising plasma nitriding (PN) followed by arc ion plating of a TiN coating was applied to 316L stainless steel. The duplex coating exhibited a bilayer structure with a TiN top layer (~1.3 μm) and a nitrided diffusion layer (~9.2 μm). Compared with a single TiN coating, it showed superior corrosion resistance in both cathode and anode environments, with corrosion current densities of 0.069 and 0.422 μA·cm⁻², respectively, and maintained stable performance over 10,000 s of potentiostatic polarization. Its interfacial contact resistance at 140 N·cm⁻² was 7.84 mΩ·cm², below the Department of Energy (DOE) 2025 target of 10 mΩ·cm². The water contact angle also increased, benefiting water management. The nitrided interlayer substantially enhanced the adhesion strength of the TiN coating. These findings confirm that the sequential combination of plasma nitriding and TiN coating is an effective strategy for improving the corrosion resistance, electrical conductivity, and adhesion of stainless steel bipolar plates for PEMFC applications.