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Improving transition metal-nitrogen-carbon (M-N-C) as a noble-metal-free catalyst for the oxygen reduction reaction (ORR) is critical to achieve low-cost electrochemical energy conversion. Herein, an in situ S doping strategy of enhancing Fe-N-C activity for ORR was developed by newly designed Fe(II) ion coordinated S-containing bis(imino)-pyridine-based polymers as precursors, which were synthesized through copolymerizing three monomers of 2, 6-diacetylpyridine (DAP), triamterene (TIT), and 2,5-dithiobiurea (DTB) as both N and S sources. All samples derived from various molar ratios of the three monomers possess a self-supporting structure of nanosheets. Additionally, incorporating DTB into the copolymer can not only strongly affect the derived coordinative species of N dopants to Fe atom but also effectively induce the synergistic effect between S dopants and FeNx moieties, resulting a significant improvement for ORR. The S-doped Fe-N-C nansheets with Fe coordinated by 4 pyrrolic N dopants exhibit the highest ORR activity and stability in alkaline media with a higher power output of Zn-air battery than that of the same loading of Pt/C. Theoretical calculation identifies that the thiophenic S dopant adjacent to Fe-pyrrolic N moiety can decrease the d band center of Fe atom, greatly weakening the energy profiles of oxygenated intermediates and thus enhancing ORR. In addition, because of the designability of transition metal coordinated S-containing bis(imino)-pyridine based polymers in the work, therefore, it is believable that this strategy would open a wide space to explore the structural relationship between precursors and MNx active sites with S dopants for the purpose of achieving highly efficient and robust M-N-C catalysts for energy-related electrocatalysis.

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Improving the utilization of Ir electrocatalysts for the oxygen evolution reaction (OER) to significantly reduce their loading is essential for low-cost hydrogen production in proton exchange membrane water electrolysis. Herein, IrCo hollow nanospheres featuring a novel structure with ultrathin continuous shells which have only eleven atomic layers (2.26 nm) were synthesized by a facile sequential reduction route using NaBH4 as a reducing agent at room temperature. It is revealed that the key intermediate in the formation of hollow nanospheres is amorphous cobalt boride formed between Co2+ and NaHB4 in the first reducing step. The average diameter of the IrCo nanospheres was found to be 73.71 nm with the atomic ratio of 47.1% and 52.9% for Co and Ir, respectively. The IrCo hollow nanospheres exhibit highly efficient OER activity and long-term durability with a low overpotential of 284 mV at 10 mA cm-2 (32.5 µgIr cm-2) and a high mass activity of 8.49 A mg-1 (5.7 times higher than that of commercial IrO2 (1.49 A mg-1) at 1.7 V. The performance is also proved using an overall water splitting device with the overpotential of 318 mV to achieve 10 mA cm-2 as well as a 17 mV shift at 5 mA cm-2 after 14 h. This improvement is critically attributed to the advantages of the hollow structure, ultrathin continuous shells which are oxidized into IrOxin situ and strong lattice strain effects induced by the specific hollow structure and alloying Co into Ir crystal lattices (1.6% against metallic iridium). These characteristics endow the hollow nanospheres with great potential to minimize the Ir loading dramatically for practical applications, compared to other previously reported structures like nanoparticles, nanoneedles and nanowires.

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In addition to common clinical features, patients with coronavirus disease 2019 (COVID-19) have varying degree of coagulation dysfunction with the risk of thrombosis and/or bleeding. COVID-19 related coagulation dysfunction is a dynamic process, which may be accompanied by the formation of disseminated intravascular coagulation and is related to the severity of the disease. The imbalance of the body's immune and inflammatory response caused by coronavirus infection is an important cause of coagulation dysfunction. Dynamic monitoring as well as early prevention and treatment are of great significance for improving the prognosis of patients. This article reviews the research progress of COVID-19 related coagulation dysfunction, to provide reference for clinical research and management.

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Electrochemical water-splitting reactions (hydrogen evolution reaction (HER) and oxygen evolution reaction (OER)) and oxygen redox reactions (oxygen reduction reaction (ORR) and OER) are core processes for electrochemical water-splitting devices, rechargeable metal-air batteries, and regenerative fuel cells. Developing highly efficient non-noble multifunctional catalysts in the same electrolyte is an open challenge. Herein, efficient Co-N-C electrocatalysts with a mixed structure comprising Co-N moieties and Co nanoparticles encapsulated in a N-doped carbon layer were prepared via pyrolysis of a new structure of Co-coordinated bis(imino)pyridine polymer constructed by 2,6-diacetylpyridine and 3,3'-diaminobenzidine. Results demonstrate that Co ion sources have a remarkable impact on the final Co-N-C performance. The Co-N-C catalyst prepared using cobalt acetate as a precursor displays remarkable overall multifunctional performance. It needs only a cell voltage of 1.66 V (obtained from the half-cell test) for the water-splitting reaction (HER/OER) to reach 10 mA·cm-2 in 1.0 M KOH, and the overall oxygen redox activity (OER/ORR) is 0.72 V in 0.1 M KOH, outperforming the reported nonprecious metal catalysts. The excellent activity is attributable to the synergistic effects between active sites with encapsulated metallic Co for HER and OER and Co-N moieties for ORR.

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Pulmonary arterial hypertension (PAH) is a multi-etiological chronic disease characterized by a progressive elevation in pulmonary resistance and vascular remodeling. Its pathogenesis is complicated. Recently, emerging researches suggest that autophagy, as a self-protection mechanism maintaining the intracellular environment homeostasis in eukaryotes, participate in the occurrence and development of various types of PAH. Autophagy can regulate the survival, apoptosis of pulmonary vascular wall cells and secretion of vasoactive substances and inflammatory cytokines, thus influencing pulmonary vascular homeostasis. Some drugs based on regulating autophagy activity can effectively improve the prognosis of PAH. In this article, the regulatory role of autophagy on the development of pulmonary hypertension is reviewed to provide insight into PAH and its treatment.

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Research into the preparation and application of metal/graphene nanocomposite materials is an important issue in the field of graphene applications. Metal nanomaterials and graphene materials have many excellent properties and have been perfectly combined into metal/graphene nanocomposite materials. These offer the high catalytic activity of metal nanomaterials and the high specific surface area and favorable electrical conductivity of graphene. The unique advantages can produce synergistic effects and can significantly improve the overall performance of the composite materials. This gives the metal/graphene nanocomposite materials excellent application prospects for hydrogen evolution. Here, we report the preparation of yttrium-doped palladium/iron on graphene (Pd/YFeO3/GC) using a simple and efficient method. The catalytic performance of the Pd/YFeO3/GC nanocomposites for water electrolysis and hydrogen production was evaluated. The results show that the overpotential for the hydrogen evolution reaction at -10 mA cm-2 is only 15 mV, which is competitive with Pt/C catalysts. The Pd/YFeO3/GC is highly active for hydrogen evolution with an onset potential of -8 mV in 0.5 M H2SO4 solution and a Tafel slope of 37 mV dec-1 with a Pd loading of only 20 µgPd cm-2. These results clearly demonstrated that Pd/YFeO3/GC is an excellent catalyst for hydrogen evolution.