3 research outputs found

    Table_1_Association between serum vitamin D and refractive status in United States adolescents: A cross-sectional study.DOCX

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    PurposeWe performed this study to determine the relationship between serum vitamin D levels and refractive status in adolescents aged 12–19 years.MethodsCross-sectional study using the National Health and Nutrition Examination Survey (NHANES) database from 2001 to 2006. We used weighted multivariate linear regression models to assess the association between serum vitamin levels and adolescent refractive status and then built a smooth curve fitting to investigate their internal non-linear relationships. Finally, subgroup analysis was performed according to gender, and the threshold effect of serum vitamin D levels on spherical equivalent degree was analyzed using a two-piecewise linear regression model.ResultA total of 5,901 adolescents aged 12 to 19 years were included in this study. After adjusting for all confounding factors, the multiple linear regression model showed no significant correlation between adolescent spherical equivalent degree and serum vitamin D [0.0019 (−0.0018, 0.0046)]. However, smooth curve fitting analysis showed an inverted U-shaped curve relationship between spherical equivalent degree and serum vitamin D levels in adolescents (turning point: 58.1 nmol/L). In analyses by gender subgroup, this inverted U-shaped relationship was found to be more pronounced in female adolescents (turning point: 61.6 nmol/L).ConclusionOur results suggest that the correlation between refractive status and serum vitamin D in adolescents differs by gender. When serum vitamin D concentrations were <61.6 nmol/L in female adolescents and <53.2 nmol/L in male adolescents, the spherical equivalent degree showed a positive correlation with serum vitamin D levels. However, there was no significant correlation when adolescent vitamin levels exceeded this threshold.</p

    Direct Synthesis of α‑Ketoamides via Copper-Catalyzed Reductive Amidation of Nitroarenes with α‑Oxocarboxylic Acids

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    Nitroarenes are known for their stability, low toxicity, easy availability, and cost-effectiveness, making them one of the most fundamental chemical feedstocks. The direct utilization of nitroarenes as nitrogen sources in amidation reactions offers significant advantages over using arylamines. Herein, we disclose a streamlined method for constructing α-ketoamides through the direct coupling of nitroarenes with α-oxocarboxylic acids. This transformation obviates the need for preparing, isolating, and purifying arylamines, leading to improved efficiency, cost-effectiveness, and time savings

    Highly Robust Room-Temperature Interfacial Ferromagnetism in Ultrathin Co<sub>2</sub>Si Nanoplates

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    The reduced dimensionality and interfacial effects in magnetic nanostructures open the feasibility to tailor magnetic ordering. Here, we report the synthesis of ultrathin metallic Co2Si nanoplates with a total thickness that is tunable to 2.2 nm. The interfacial magnetism coupled with the highly anisotropic nanoplate geometry leads to strong perpendicular magnetic anisotropy and robust hard ferromagnetism at room temperature, with a Curie temperature (TC) exceeding 950 K and a coercive field (HC) > 4.0 T at 3 K and 8750 Oe at 300 K. Theoretical calculations suggest that ferromagnetism originates from symmetry breaking and undercoordinated Co atoms at the Co2Si and SiO2 interface. With protection by the self-limiting intrinsic oxide, the interfacial ferromagnetism of the Co2Si nanoplates exhibits excellent environmental stability. The controllable growth of ambient stable Co2Si nanoplates as 2D hard ferromagnets could open exciting opportunities for fundamental studies and applications in Si-based spintronic devices
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