Search

Capacitive deionization (CDI) is an emerging technique of seawater desalination technology with high efficiency and low energy consumption. Prussian blue (PB) is considered to be an excellent candidate for CDI intercalation electrode materials due to its spacious three-dimensional ion diffusion channels and available low-cost raw materials. However, the agglomerate tendency and inferior electronic conductivity of PB are the main factors which lead to lower capacity and poor cycling stability. Herein, a Prussian blue nanoparticle/carbon nanofiber (PB/CNF) composite material was synthesized by electrospinning and coprecipitation for capacitive deionization. The conductive CNFs bridged the PB nanoparticles with a size of ca. 50 nm to form a 3D conductive network structure, which can boost the diffusion kinetics of salt ions and electrons simultaneously in the PB/CNF electrode. The ion storage process by the combination of capacitance-controlled and diffusion-controlled behaviors allows the PB/CNF-5 composite to achieve a salt adsorption capacity (SAC) of 51.81 mg g–1 in a 500 mg L–1 NaCl solution at 1.4 V, and it has excellent cycle stability for 80 cycles. Remarkably, it also shows an excellent salt adsorption performance of 97.35 mg g–1 in a 3000 mg L–1 NaCl solution. Overall, the strategy of antiaggregation and enhanced electronic conductivity not only improved the desalination performance of PB nanoparticles but also provided a technical guideline for nanometer-sized materials and helped to facilitate better CDI electrode design. [ABSTRACT FROM AUTHOR]

Mechanical force is essential to shape the internal architecture and external form of the skeleton by regulating the bone remodeling process. However, the underlying mechanism of how the bone responds to mechanical force remains elusive. Here, we generated both orthodontic tooth movement (OTM) model in vivo and a cyclic stretch‐loading model in vitro to investigate biomechanical regulation of the alveolar bone. In this study, signal transducer and activator of transcription 3 (STAT3) was screened as one of the mechanosensitive proteins by protein array analysis of cyclic stretch‐loaded bone mesenchymal stem cells (BMSCs) and was also proven to be activated in osteoblasts in response to the mechanical force during OTM. With an inducible osteoblast linage‐specific Stat3 knockout model, we found that Stat3 deletion decelerated the OTM rate and reduced orthodontic force‐induced bone remodeling, as indicated by both decreased bone resorption and formation. Both genetic deletion and pharmacological inhibition of STAT3 in BMSCs directly inhibited mechanical force‐induced osteoblast differentiation and impaired osteoclast formation via osteoblast–osteoclast cross‐talk under mechanical force loading. According to RNA‐seq analysis of Stat3‐deleted BMSCs under mechanical force, matrix metalloproteinase 3 (Mmp3) was screened and predicted to be a downstream target of STAT3. The luciferase and ChIP assays identified that Stat3 could bind to the Mmp3 promotor and upregulate its transcription activity. Furthermore, STAT3‐inhibitor decelerated tooth movement through inhibition of the bone resorption activity, as well as MMP3 expression. In summary, our study identified the mechanosensitive characteristics of STAT3 in osteoblasts and highlighted its critical role in force‐induced bone remodeling during orthodontic tooth movement via osteoblast–osteoclast cross‐talk. © 2022 American Society for Bone and Mineral Research (ASBMR). [ABSTRACT FROM AUTHOR]

Drastically lowering the usage of platinum while enhancing activity and stability toward oxygen reduction is critical to promoting energy conversion efficiency in metal‐air batteries. Herein, an efficient oxygen reduction catalyst was rationally designed by constructing ultrasmall Pt and Pt/MoC dual active sites co‐anchored on nitrogen‐doped carbon. Owing to the synergistic effect of the dual active sites, the optimized Pt‐MoC@NC delivers superior oxygen reduction activity with ultralow Pt loading. Especially, the Pt‐MoC@NC shows robust methanol tolerance. As the cathodic catalyst, Pt‐MoC@NC based zinc‐air battery possesses outstanding performance with a large peak power density of 100 mW cm−2 and long charge‐discharge durability. [ABSTRACT FROM AUTHOR]

This work demonstrated the development of a hierarchical porous carbon–carbon composite used as an electrode material for capacitive deionization. The novel core–shell composite consisting of carbon nanofibers and N-rich porous carbon nanosheets (CNFZIF) was obtained by in situ growth of zeolitic imidazolate framework-8 (ZIF-8) nanosheets on electrospun nanofibers. By tailoring the composition and porosity of CNFZIF, ion transport and adsorption in the composite were tuned to achieve a large desalination capacity and a high desalination rate. Thanks to the synergistic effect of its N-rich carbon surface, high hydrophilicity, large specific surface area and unique hierarchical porous structure, the engineered CNFZIF sample exhibited an excellent capacitive deionization performance with a maximum desalination capacity of up to 50.88 mg g−1 for NaCl solution and a high capacity retention rate of 97% after 30 cycles. Remarkably, CNFZIF also demonstrated high desalination capacities of 27.19 mg g−1, 25.35 mg g−1 and 20.46 mg g−1 for CaCl2, MgCl2, and KCl solutions, respectively. This work provided a new route for the design of advanced electrode materials, and therefore represents a major step forward in the development of electrodes for capacitive deionization applications. [ABSTRACT FROM AUTHOR]

Melanosomes in nature have diverse morphologies, including spheres, rods, and platelets. By contrast, shapes of synthetic melanins have been almost entirely limited to spherical nanoparticles with few exceptions produced by complex templated synthetic methods. Here, we report a non‐templated method to access synthetic melanins with a variety of architectures including spheres, sheets, and platelets. Three 1,8‐dihydroxynaphthalene dimers (4‐4′, 2‐4′ and 2‐2′) were used as self‐assembling synthons. These dimers pack to form well‐defined structures of varying morphologies depending on the isomer. Specifically, distinctive ellipsoidal platelets can be obtained using 4‐4′ dimers. Solid‐state polymerization of the preorganized dimers generates polymeric synthetic melanins while maintaining the initial particle morphologies. This work provides a new route to anisotropic synthetic melanins, where the building blocks are preorganized into specific shapes, followed by solid‐state polymerization. [ABSTRACT FROM AUTHOR]