Fluorine is one of the trace elements necessary for health. It has many physiological functions, and participates in normal metabolism. However, fluorine has paradoxical effects on the body. Many studies have shown that tissues and organs of humans and animals appear to suffer different degrees of damage after long‐term direct or indirect exposure to more fluoride than required to meet the physiological demand. Although the aetiology of endemic fluorosis is clear, its specific pathogenesis is inconclusive. In the past 5 years, many researchers have conducted in‐depth studies into the pathogenesis of endemic fluorosis. Research in the areas of fluoride‐induced stress pathways, signalling pathways and apoptosis has provided further extensive knowledge at the molecular and genetic level. In this article, we summarize the main results.

Generally, a homogeneous catalyst exhibits good activity and defined active sites but it is difficult to recycle. Meanwhile, a heterogeneous catalyst can easily be reused but its active site is difficult to reveal. It is interesting to bridge the gap between homogeneous and heterogeneous catalysis via controllable construction of a heterogeneous catalyst containing defined active sites. Here, we report that a molecularly defined, single-active site heterogeneous catalyst has been designed and prepared via the oxidative polymerization of maleimide derivatives. These polymaleimide derivatives can be active catalysts for the selective oxidation of heterocyclic compounds to quinoline and indole via the recycling of –C=O and –C–OH groups, which was confirmed by tracing the reaction with GC-MS using maleimide as the catalyst and by FT-IR analysis with polymaleimide as the catalyst. These results might promote the development of heterogeneous catalysts with molecularly defined single active sites exhibiting a comparable activity to homogeneous catalysts.