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Abstract Osteoporosis is a metabolic bone disease that involves gradual loss of bone density and mass, thus resulting in increased fragility and risk of fracture. Inflammatory cytokines, such as tumour necrosis factor α (TNF‐α), inhibit osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and several microRNAs are implicated in osteoporosis development. This study aimed to explore the correlation between TNF‐α treatment and miR‐27a‐3p expression in BMSC osteogenesis and further understand their roles in osteoporosis. An osteoporosis animal model was established using ovariectomized (OVX) mice. Compared with Sham mice, the OVX mice had a significantly elevated level of serum TNF‐α and decreased level of bone miR‐27a‐3p, and in vitro TNF‐α treatment inhibited miR‐27a‐3p expression in BMSCs. In addition, miR‐27a‐3p promoted osteogenic differentiation of mouse BMSCs in vitro, as evidenced by alkaline phosphatase staining and Alizarin Red‐S staining, as well as enhanced expression of the osteogenic markers Runx2 and Osterix. Subsequent bioinformatics analysis combined with experimental validation identified secreted frizzled‐related protein 1 (Sfrp1) as a downstream target of miR‐27a‐3p. Sfrp1 overexpression significantly inhibited the osteogenic differentiation of BMSCs in vitro and additional TNF‐α treatment augmented this inhibition. Moreover, Sfrp1 overexpression abrogated the promotive effect of miR‐27a‐3p on the osteogenic differentiation of BMSCs. Furthermore, the miR‐27a‐3p–Sfrp1 axis was found to exert its regulatory function in BMSC osteogenic differentiation via regulating Wnt3a–β‐catenin signalling. In summary, this study revealed that TNF‐α regulated a novel miR‐27a‐3p–Sfrp1 axis in osteogenic differentiation of BMSCs. The data provide new insights into the development of novel therapeutic strategies for osteoporosis.

Inkjet printing of two-dimensional (2D) perovskite nanosheets offers a promising avenue for manufacturing high-performance microcapacitors. However, optimizing and improving the dielectric performance of these printed microcapacitors remains a significant challenge. Here, Bi-doped Sr2Nb3O10 perovskite nanosheets are engineered, dispersed in an environmentally friendly water/ethanol mixed solvent, and meticulously assembled with Ag and graphene into microcapacitors by inkjet printing technology. Enhanced dielectric performance is achieved by controlling the Bi doping content and fine-tuning the electrode/dielectric interface. A high capacitance density of approximately 193 nF cm−2 and an impressive dielectric constant reaching up to 250 are demonstrated in inkjet-printed graphene/Sr1.7Bi0.3Nb3O10/graphene microcapacitors. Such microcapacitors also feature good insulating performance with a moderate electrical breakdown strength of ∼1 MV cm−1, robust flexibility, strong electric field stability within 40 V, excellent stability up to 200 °C, and moderate reproducibility of ∼76.7%. Additionally, these devices exhibit a high sensitivity to chemical solvents of different polarities, which can significantly enhance the dielectric performance of these printed microcapacitors. Our work may provide an effective route to improve the dielectric performance of inkjet-printed microcapacitors based on 2D dielectric nanosheets. [ABSTRACT FROM AUTHOR]

Non-transition metal doping, especially for Mg, has been gradually employed to optimize the electrochemical performance of Li-rich cathode material Li2MnO3. However, the effects of Mg doping on the electrochemical behavior of Li2MnO3 have not been studied extensively. In this work, we investigate the effect of Mg doping at both the 2b (in the Li/Mn mixed layer) and 4h (in the Li layer) Li sites on the electrochemical properties of Li2MnO3 through first-principles calculations and ab initio molecular dynamics simulations. The local lattice structure, electronic density of states, Bader charge, delithiation voltage, lattice oxygen stability and Li diffusion kinetics are examined. Electronic structure analysis shows that Mg can activate the electrochemical activity of surrounding Mn by charge transfer, making Mn participate in charge compensation at the initial delithiation stage. Mg doping can also cause an increase in the average oxygen vacancy formation energy and hence depress the oxygen release during the delithiation process. Molecular dynamics simulations show that the diffusion kinetics of Li ions in Mg2b–Li2MnO3 is enhanced with respect to the undoped one, whereas Mg doped at the 4h site cannot improve the diffusion kinetics of Li ions. Further studies found that Mg doped at the 2b site results in a decrease in the energy barrier for the intra-layer diffusion and an increase in the energy barrier for the inter-layer diffusion of the nearby Li vacancies. [ABSTRACT FROM AUTHOR]

The formation of a core–shell structure by coating silicon (Si) nanoparticles with a carbon layer is considered a promising method to address the poor conductivity of a Si-based anode and volume expansion of silicon particles during the charging/discharging process. However, Si/C composite anodes usually perform below expectations with a single layer of carbon utilized as the coating layer, while introducing multilayer carbon coating results in the additional complexity and cost. To overcome this challenge, in this work, waterborne polyurethane (WPU) had been simply mixed with the Si nanoparticles to form the Si/WPU composite via the hydrogen bonds, and the core–shell structure with the single carbon layer containing N atoms (Si@NC) was obtained after the pyrolysis of the composite. The carbon layer not only significantly alleviated the breakage of the anode caused by the volume expansion of Si nanoparticles but also optimized the rate performance of the anode. At a current density of 0.5 A g–1, the discharge specific capacity of the Si@NC anode is still as high as 945.63 mAh g–1 after 300 cycles, surpassing various single-layer carbon and multilayer carbon-coated Si-based anodes. This work provides a convenient and feasible method for preparing economical Si/C composite anode materials. [ABSTRACT FROM AUTHOR]

Rechargeable Li‐O2 batteries (LOBs) are regarded as promising candidates for the next generation of energy storage devices. One of the major impediments is the poor cycle stability resulting from unreliable cathode catalysts and serious corrosion of Li anode, hindering the commercial application of LOBs. Herein, a synergetic strategy is proposed, including the design of a stable Co3Ru cathode catalyst via d‐band center modulation and the construction of a robust LiF/Sn/Li5Sn2‐PFDTMS hybrid protective layer on Li anode. Theoretical calculations reveal that the negative shift of the d‐band center provides a dominant descriptor for improving the catalysis activity and stability of Ru‐based catalysts. In situ construction of the PFDTMS‐enhanced LiF/Sn/Li5Sn2 hybrid layer possesses excellent mechanical stability and toughness, which can effectively shield the Li anode from corrosive reaction and ensure good Li+ transport. Consequently, the LOBs exhibit a long cycle life of 990 cycles (≈1980 h). This work confers the concept for high‐performance LOBs via rationally constructing stable catalysts and Li anodes. [ABSTRACT FROM AUTHOR]

Assembling transition-metal oxides (TMOs) and MXene with strong interfacial interactions is an effective method to overcome the drawbacks of TMOs as anodes for lithium-ion batteries (LIBs) such as large volume expansion and low conductivity. Herein, a CuO nanorod/MXene heterojunction (denoted as CuO/MXene) with a synergistic effect was constructed with a "sheet-rod-pore" hierarchical nanostructure by electrostatic self-assembly. Specifically, encapsulated CuO nanorods exert superiority in the high reversible capacity and increase the interlayer distance of the MXene matrix to explore more storage spaces. MXene could significantly boost the conductivity, accommodate volume variation, and inhibit structure collapse as a buffer network. Density functional theory (DFT) calculations confirm the strong electron transport and lithium affinity at the CuO/MXene heterointerface, elucidating the reasons for the enhanced lithium storage capacity (436.4 mAh g–1 at 500 mA g–1), ion diffusion kinetics, and structural stability after cycling than pure CuO and MXene. When paired with the LiCoO2 cathode, the full cell delivers good cycling stability after 140 cycles, indicating the practical applicability of CuO/MXene. This work not only validates the robust interfacial interaction of TMO/MXene heterojunction but also explores an effective strategy to prepare promising anode materials for the next-generation LIBs. [ABSTRACT FROM AUTHOR]