No abstract

Stimuli‐responsive fluorescent materials with aggregation‐induced emission (AIE) characteristics have attracted increasing attention owing to their advantages of bright fluorescence in the solid state and the ability to tune the structures and physicochemical performances in response to various stimuli. Among all the available external stimuli, light stands out, and has rapidly become a focus of research, because it offers green and remote triggering, noninvasive manipulation, high spatiotemporal resolution, and convenient tunable properties. Consequently, photo‐responsive AIE materials provide a fascinating strategy for constructing functional fluorescent materials. This review summarizes the recent advances in the fabrication of photo‐responsive fluorescent materials with AIE characteristics by grafting AIE fluorogens (AIEgens) into photochromic molecules. State‐of‐the‐art photo‐responsive AIE materials based on the inherent photochemical reactions of AIEgens are highlighted, and are classified and discussed according to the photochemical pathways, including photocyclization, photo‐isomerization, photodimerization, photo‐removal, and multiple photoreactions. Following this, the corresponding applications of photo‐responsive AIE materials in bio‐imaging, anti‐counterfeiting, photo‐patterning, photo‐release of chemicals or drugs, and photo‐controlled assembly and disassembly are introduced. Finally, the most promising directions for development and applications of photo‐responsive AIE materials are outlined and discussed.

Developing efficient and affordable alternatives for Pt-based electrocatalysts to promote the procedure of hydrogen evolution reaction (HER) is of significant importance. Herein, a facile and convenient strategy using tris­(2,2′-bipyridyl)­ruthenium­(II) chloride hexahydrate as precursor is developed for synthesizing ultrafine and highly dispersed ruthenium nanoclusters on carbon support. It is discovered that the preadsorption of Ru precursor on carbon substrate and followed by pyrolysis are very crucial for the synthesis of such Ru nanoclusters. Among as-prepared samples, Ru/CN-800 shows the best HER electrocatalytic performance in alkaline solution, which outperforms the benchmark Pt/C and recently reported catalysts. The excellent performance of Ru/CN-800 was presumably attributed to the dominant metallic Ru as well as the ultrasmall Ru nanoclusters with a satisfied dispersion, which provides the massive highly active sites for HER. This facile and environmental-friendly pathway for synthesis of ultrasmall Ru nanoclusters with high HER activity shows a promise in practical applications.

No abstract

We investigated the role of M1 and M3 receptors in regulating exocrine secretion from acini isolated from rat sublingual glands. In secretion experiments, we derived affinity values (KB) from Schild regression analysis for the antagonists pirenzepine (61.0 nM) and 4-diphenylacetoxy-N-methylpiperidine (4-DAMP; 1.06 nM). The KB for 4-DAMP is similar to its affinity value [equilibrium dissociation constant from competition studies (Ki); 1.81 nM] determined from radioligand competition experiments. In contrast, the KB for pirenzepine is between its high-affinity (17.6 nM) and low-affinity (404 nM) Ki values. In separate secretion experiments, we found that the M1 receptor antagonist, M1-toxin, induces a rightward shift in the concentration-response curve to muscarinic agonist and inhibits maximal secretion by 40%. The inhibitory effect of M1-toxin appears specific for M1 receptor blockade, since the toxin abolishes acinar high-affinity pirenzepine-binding sites and does not inhibit secretion induced by nonmuscarinic agents. Additional pharmacological studies indicate muscarinic receptors do not function through putative neural elements within isolated acini. Our combined results are consistent with both M1 and M3 receptors directly regulating mucous acinar exocrine secretion and indicate M3 receptors alone are insufficient to induce a maximal muscarinic response.