As an essential nutrient and trace element, selenium is required for living organisms and its beneficial roles in human health have been well recognized. The role of selenium is mainly played through selenoproteins synthesized by the selenium metabolic system. Selenoproteins have a wide range of cellular functions including regulation of selenium transport, thyroid hormones, immunity, and redox homeostasis. Selenium deficiency contributes to various diseases, such as cardiovascular disease, cancer, liver disease, and arthropathy—Kashin–Beck disease (KBD) and osteoarthritis (OA). A skeletal developmental disorder, KBD has been reported in low-selenium areas of China, North Korea, and the Siberian region of Russia, and can be alleviated by selenium supplementation. OA, the most common form of arthritis, is a degenerative disease caused by an imbalance in matrix metabolism and is characterized by cartilage destruction. Oxidative stress serves as a major cause of the initiation of OA pathogenesis. Selenium deficiency and dysregulation of selenoproteins are associated with impairments to redox homeostasis in cartilage. We review the recently explored roles of selenium metabolism and selenoproteins in cartilage with an emphasis on two arthropathies, KBD and OA. Moreover, we discuss the potential of therapeutic strategies targeting the biological functions of selenium and selenoproteins for OA treatment.

A new, efficient Cu-catalyzed intramolecular C-H oxidation/acylation method has been developed for the synthesis of substituted indoline-2,3-diones (isatins). In the presence of CuCl(2) and O(2), a variety of formyl-N-arylformamides underwent the tandem reaction to afford the corresponding indoline-2,3-diones in moderate to good yields. It is noteworthy that the reaction serves as the first example of transition-metal-catalyzed transformation for the preparation of indoline-2,3-diones.

Due to the harsh reaction conditions, high energy consumption, and numerous carbon emissions of the traditional Haber–Bosch method, the fixation of nitrogen under environmentally friendly and milder conditions is of great importance. Recently, photoelectrochemical (PEC) strategies have attracted extensive attention, where the catalysts with the advantages of cost-effectiveness and improved efficiency are critical for the nitrogen reduction reaction (NRR). Herein, we synthesized nitrogen vacancies that contained g-C3N5 (NV-g-C3N5) and combined with BiOBr to construct the p–n heterostructure NV-g-C3N5/BiOBr, in which the double-electron transfer mechanism was constructed. In one side, the nitrogen vacancies store the electrons coming from the g-C3N5 and provide for the nitrogen activation when needed; in addition, NV-g-C3N5/BiOBr further separates photoinduced electrons and holes because of the matched “Z”-shaped energy band structure. The double-electron transfer mechanism effectively retards the recombination of charge carriers and ensures the support of high-quality electrons, which results in excellent PEC NRR performance without the addition of noble metals. Although yields and durability are insufficient, the described double-electron transfer mechanism manifests the potential of the non-noble metal material in the PEC NRR, providing a foundation for the design of a more affordable and efficient photocathode in nitrogen reduction.

We developed a simple and facile one-pot hydrothermal methods for synthesis of GO-dots without the need to use strong concentrated acid and the entire synthetic process only took 90 min.

No abstract