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Tungsten carbide (WC)-based materials are widely considered as the hydrogen evolution reaction (HER) process catalysts due to their “Pt-like” electronic structure. Nonetheless, traditional powder electrodes have a high cost, and display problems related to the process itself and the poor stability over operation time. This paper presented a self-supported asymmetric porous ceramic electrode with WO3−x whiskers formed in situ on the walls of the finger-like holes and membrane surface, which was prepared by combining phase inversion tape-casting, pressureless sintering, and thermal treatment in a CO2 atmosphere. The optimized ceramic electrode displayed good catalytic HER activity and outstanding stability at high current densities. More specifically, it demonstrated the lowest overpotentials of 107 and 123 mV and the lowest Tafel slopes of 59.3 and 72.4 mV·dec−1 at 10 mA·cm−2 in acidic and alkaline media, respectively. This superior performance was ascribed to the structure of the ceramic membrane and the charge transfer efficiency, which was favored by the in situ developed WC/WO3−x heterostructure and the oxygen vacancies.

Phosphors of SrAl2O4:Eu (SAO), B-doped (SBO), and B, F co-doped (SFO) were prepared by a high-temperature solid-state reaction method. The phosphors emit intense green light under UV excitation. SBO displayed significantly enhanced long afterglow. The decay time of SBO was 20 times bigger than that of SAO, while that of SFO was only 16% of that of SBO. The results suggest that B doping favors the formation of oxygen vacancies due to the unique bonding property of B. At the same time, B, F co-doping has the opposite effect, ascribed to the presence of F. The related partial density of state and the orbital structures were calculated using the first-principles density functional theory (DFT). The orbital structure of SBO showed that high partial density states are localized around the O vacancies, which can trap excited electrons, leading to improved long-afterglow luminescence.

Particle size reduction of Y3Al5O12:Ce (YAG:Ce) phosphor is highly needed for Micro-LED display applications. In this work, size control of Y3Al5O12:Ce phosphor particles is achieved via carbon coating and further heat treatment. A thin layer of carbon is deposited on the surface of Y3Al5O12:Ce by chemical vapor deposition (CVD). During the heat treatment, carbon reacted with oxygen element in the phosphor and escape from phosphor particles. The reaction results in the phosphor breaking into smaller particles. The phosphors are characterized by laser light scattering for particle size distribution, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for morphologies, XRD refinements for crystal structure, electron energy-loss spectroscopy (EELS) for elemental analysis. It is demonstrated that the median diameter (D50) of the phosphor particle size has been significantly reduced from 19.1 to 0.96 μm yet the photoluminescent properties have little changes. The carbon coating and further heat treatment method shows potential application in size control of phosphors.

ZrB2 is widely used in refractory linings and electrodes as well as in a range of applications including microelectronics and cutting tools, owing to its excellent characteristics, such as high hardness, high melting point, high strength, high thermal conductivity, and good thermal shock resistance. However, ZrB2 readily oxidizes, especially at high temperatures, which is ascribed to the reaction between ZrB2 and O2 in air. This study shows that a structural self-deterioration phenomenon occurs in ZrB2, even in vacuum or inert atmosphere. ZrB2 exhibits a characteristic, irreversible increase in resistivity in a high vacuum–high temperature environment. During repeated variable temperature resistivity testing, the resistivity of ZrB2 increases by 3.28% in the first cycle and 0.61% in the second. To investigate further, in-situ TEM showed that ZrB2 experiences an unusual phase transition reaction at high temperatures, even under a high vacuum environment. Oxidation results in a large number of disordered, layered structures and holes inside the ZrB2 particles. This microstructure evolution mechanism decreases the electrical conductivity and affects the performance of ZrB2. The study demonstrates the need to thoroughly investigate the microstructure changes in ZrB2 at high temperatures, under an inert atmosphere or high vacuum, and to widen the investigations to other properties beyond electrical resistivity.

The high-temperature applications of zirconium diboride (ZrB2) ceramics are hindered due to their easy initial oxidation at temperature around 700 °C. Although mixing and coating methods have been introduced to enhance the oxidation resistance of ZrB2-based ceramics, their thorough comparative analysis still demands a more systematic exploration. Herein, spark plasma sintered ZrB2@20 vol% LaF3 and ZrB2+20 vol% LaF3 ceramics prepared by coating and mixing powders, respectively, were used to study the influence of dispersion method of LaF3 on their oxidation resistance. After oxidation at 1000 °C for 4 h, a thin oxide layer (~25 μm) and low weight gain (9%) confirmed the superior oxidation resistance of ZrB2+20 vol% LaF3 over ZrB2@20 vol% LaF3, which could be attributed to the formation of a dense surface layer due to the self-healing mechanism. In turn, the poor oxidation resistance of ZrB2@20 vol% LaF3 was caused by the “anchoring” of LaF3 cladding layer and locally-coated ZrB2 particles, which led to the in situ reactions and formation of a porous oxide scale (~400 μm). Finally, the discrepant oxidation resistance mechanisms of ZrB2–LaF3 ceramics obtained by different dispersion methods of LaF3 were proposed.

ZrB2-based ceramics are important materials for a variety of applications. However, their low oxidation resistance above 1000 °C limits their high-temperature applications. Herein, we report the utilization of LaF3 as a unique oxidation retardant to significantly improve the oxidation resistance of ZrB2-10 vol%LaF3 ceramics in the temperature range of 1000–1400 °C. Moreover, we present the densification of the oxide layer via oxidation-induced self-healing mechanism of ZrB2–LaF3 ceramics for the first time. The incorporation of LaF3 into ZrB2 matrix was achieved by using spark plasma sintering at 1800 °C. Furthermore, the oxidation behavior of pure ZrB2 and ZrB2-10 vol%LaF3 ceramics was systematically investigated by analyzing the thicknesses of oxide layers and the weight gains. Both the thicknesses and weight gain were significantly reduced after adding 10 vol. % LaF3, which can be mainly attributed to the synergistic influence of pore filling and healing by LaB3O6/LaBO3 phases and corresponding volumetric expansions.

The hydrogen evolution reaction (HER) is an emerging renewable energy source to derive clean, efficient, and high-energy-density hydrogen fuel from electrochemical water splitting mostly by using t...

Most of the magnetic microwave absorbers are ineffective in extreme corrosive environments of acids and alkalis which abruptly reduce their performance. Therefore, it is urgent and worthwhile to produce the bifunctional materials with excellent corrosion resistance and microwave absorption property. This work presents the in-situ growth of double shells of silica and carbon on FeSiAl (FSA) alloy surface to obtain an integrated FSA@SiO2@C hybrid structure via combined Stober and catalytic chemical vapor deposition (CCVD) techniques. The hybrid structure acquires the strengthened bi-functional for anti-corrosion and microwave absorption due to the excellent corrosion shielding protection and well dielectric properties of SiO2 and carbon hybrid structure. Importantly, the hybrid morphology retains excellent stability of more than 150 h in 5.0 wt% NaCl acid solution. Moreover, FSA@SiO2@C hybrid possesses enhanced microwave absorption performance with a minimum reflection loss (RLmin) of −46.75 dB at 5.74 GHz with a matching thickness of 3.5 mm, and the effective bandwidth (RL

Chemical stability of phosphors is critical to the efficiency and lifetime of the white light-emitting diodes. Therefore, many strategies have been adopted to improve the stability of phosphors. However, it is still lack of report on the improvement of thermal stability and hydrolysis resistance of phosphors by a single layer coating. Due to the high transmittance and high chemical inertness of graphene, it was coated on the surface of Sr2Si5N8:Eu2+ phosphor by chemical vapor deposition, aiming to improve its thermal stability and hydrolysis resistance. The chemical composition and microstructure of the coating were characterized and analyzed. A nanoscale carbon layer was attached on the surface of Sr2Si5N8:Eu2+ phosphor particles in an amorphous state. In coated Sr2Si5N8:Eu2+ phosphor, the oxidation degree of Eu2+ to Eu3+ was significantly suppressed. At the same time, the surface of Sr2Si5N8:Eu2+ particle turned from hydrophilic to hydrophobic after carbon coating, and consequently the hydrolysis resistance of Sr2Si5N8:Eu2+ phosphor was greatly improved. After tests at 85 °C and 85% humidity for 200 h, the carbon coated Sr2Si5N8:Eu2+ phosphor still maintained about 95% of its initial luminous intensity as compared with 35% of the uncoated. By observing the in-situ microstructure evolution of coated phosphor in air-water vapor environment, remained presence of the carbon layer even at 500 °C explained the excellent chemical stability of carbon coated Sr2Si5N8:Eu2+ phosphor in complex environment. These results indicate that a nanoscale carbon layer can be used to provide superior thermal stability and hydrolysis resistance of (oxy) nitrides phosphors.

Low infrared emissivity in 3–5 μm or 8–14 μm band has been realized in different host materials. Realizing the low infrared emissivity in single material covering the entire band is rarely achieved. This research explores a binary system of ultra-high temperature ceramic ZrB2–CeO2 composites prepared by solid state sintering. their phase composition, microstructure evolution, reaction mechanism and infrared emissivity performance were discussed in detail. It was found that CeO2, ZrB2, ZrO2, and ZrnCe1-nO2 existed in the sample in addition to the coated glass phase of CeO2 on the surface of the sample. In-situ HRTEM results clearly revealed a series of reaction mechanism of CeO2 and ZrB2. With the increase of sintering temperature, the CeO2 particles gradually transformed into a glass phase, and were distributed on the surface of ZrB2 particles, and ZrO2 was formed on the surface of ZrB2, simultaneously. Consequently, ZrnCe1-nO2 is formed as the reaction of ZrO2 and CeO2. Compared with the infrared emissivity spectra of pure CeO2 and ZrB2, a low infrared emissivity less than 0.2 in a wider coverage band of 3–5 and 8–14 μm in ZrB2–CeO2 compounds was achieved as a result of synergistic interaction between CeO2 and ZrB2. The obtained information about the phase composition and microstructure evolution helps to realize low infrared emissivity in a wider coverage band in compounds via composition and microstructure modification.

K2SiF6:Mn4+ phosphor is well known for its excellent red emission performance which is vital for improving the color rendering of white light-emitting diodes. However, the poor moisture resistance limits its application in optical devices. In this paper, K2SiF6:Mn4+ phosphor is coated with an inorganic hydrophobic protective layer to obtain good moisture resistance. Chemical vapor deposition method was used to decompose acetylene at high temperature, and the generated nanoscale carbon layer worked as a hydrophobic protective coating on the surface of the phosphor. Microstructure, compositions and properties of the synthesized K2SiF6:Mn4+@C phosphor were investigated in detail. It is found that most of the deposited carbon is coated on the surface of phosphor crystals in amorphous state. The carbon atoms are bonded with the fluorine element in K2SiF6:Mn4+ phosphor, forming carbon-fluorine (C–F) covalent bonds. The moisture resistance of K2SiF6:Mn4+@C phosphor is improved owing to the protection of the hydrophobic carbon. The relative emission intensity of K2SiF6:Mn4+@C phosphor could maintain 73% of the initial luminous intensity after immersing in the aqueous solution at room temperature for 8 h, whereas K2SiF6:Mn4+ phosphor without carbon coating was only 0.7% remaining of the initial value under the same conditions.

The treatment options of acute Achilles tendon rupture (AATR) remain controversial. This article aims to compare the efficacy of a new surgical procedure, the panda rope bridge technique (PRBT) with open surgery of AATR.Ninety-eight patients with AATR were recruited, 53 underwent the PBRT, and 45 underwent open surgery. The operation time, postoperative American Orthopaedic Foot and Ankle Score, Achilles Tendon Rupture Score, complications and time to return to work and restore exercise were documented.The average operation time, intraoperative blood loss and complication rate were 35.1 min, 18.2 ml and 3.8%, respectively, in the PRBT group, which were significantly lower than those of the open surgery group (P0.001). The post-operative American Orthopaedic Foot and Ankle Score of 99.6 and the Achilles Tendon Rupture Score of 97.5 in the PRBT group were significantly higher than that of the open surgery group (P0.001). The time to return to work and return to exercise were shorter in the PRBT group (P0.001).Compared to open surgery, PRBT is a better approach to the management of AATR. PRBT offers accelerated recovery, lower occurrence of post-operative complications and improved recovery of ankle joint function.

Reconstruction of bone defects is one of the most substantial and difficult clinical challenges in orthopedics. Transforming growth factor beta 1 (TGFβ1) might play an important role in stimulating osteogenic differentiation of bone morphogenetic protein 9 (BMP9)-induced C3H10T1/2 mesenchymal stem cells. In our current study, we examined the potential synergy between TGFβ1 and BMP9 in promoting the osteogenesis of C3H10T1/2 cells, and whether such effects could contribute to bone formation in vivo. Our experiment data indicated that TGFβ1 could increase the expression of osteogenic markers and the formation of mineralized calcium nodules in, while suppressing the proliferation of, BMP9-induced C3H10T1/2 cells. Furthermore, mice intramuscularly injected with BMP9/TGFβ1-transduced C3H10T1/2 cells into the gastrocnemius muscle on their tibiae developed ectopic bone masses with more mature osteoid structures, compared to those grafted with cells expressing BMP9/RFP. Subsequent mechanistic studies found that TGFβ1-induced enhancement of osteogenesis in BMP9-overexpressing C3H10T1/2 cells was accompanied by augmented expression of heat shock protein 47 (HSP47), a collagen-specific molecular chaperone essential for collagen biosynthesis, and can be attenuated by pirfenidone, a known anti-fibrotic inhibitor. Interestingly, protein microarray analysis suggested that TGFβ1/BMP9-dependent osteogenesis of C3H10T1/2 cells seemed to involve several non-canonical signaling pathways such as Janus kinase-signal transducer and activator of transcription, phosphoinositide-3-kinase-protein kinase B, and mitogen-activated protein kinase. These results provided further evidence that TGFβ1 could promote bone formation from BMP9-induced C3H10T1/2 cells and shed important light on the underlying molecular mechanisms.

Congenital scoliosis (CS) is a complex genetic disorder characterized by vertebral malformations. The precise etiology of CS is not fully defined. Here, we identify that mutation in dual serine/threonine and tyrosine protein kinase (dstyk) lead to CS-like vertebral malformations in zebrafish. We demonstrate that the scoliosis in dstyk mutants is related to the wavy and malformed notochord sheath formation and abnormal axial skeleton segmentation due to dysregulated biogenesis of notochord vacuoles and notochord function. Further studies show that DSTYK is located in late endosomal/lysosomal compartments and is involved in the lysosome biogenesis in mammalian cells. Dstyk knockdown inhibits notochord vacuole and lysosome biogenesis through mTORC1-dependent repression of TFEB nuclear translocation. Inhibition of mTORC1 activity can rescue the defect in notochord vacuole biogenesis and scoliosis in dstyk mutants. Together, our findings reveal a key role of DSTYK in notochord vacuole biogenesis, notochord morphogenesis and spine development through mTORC1/TFEB pathway., Congenital scoliosis is a complex genetic disorder characterized by vertebral malformation. Here, the authors demonstrate that loss of dstyk leads to scoliosis in zebrafish due to dysregulated biogenesis of notochord vacuoles and that DSTYK is required for lysosome biogenesis through mTORC1 regulation.

ObjectivesThis study aims to investigate the role and mechanism of FGFR3 in macrophages and their biological effects on the pathology of arthritis.MethodsMice with conditional knockout of FGFR3 in myeloid cells (R3cKO) were generated. Gait behaviours of the mice were monitored at different ages. Spontaneous synovial joint destruction was evaluated by digital radiographic imaging and μCT analysis; changes of articular cartilage and synovitis were determined by histological analysis. The recruitment of macrophages in the synovium was examined by immunostaining and monocyte trafficking assay. RNA-seq analysis, Western blotting and chemotaxis experiment were performed on control and FGFR3-deficient macrophages. The peripheral blood from non-osteoarthritis (OA) donors and patients with OA were analysed. Mice were treated with neutralising antibody against CXCR7 to investigate the role of CXCR7 in arthritis.ResultsR3cKO mice but not control mice developed spontaneous cartilage destruction in multiple synovial joints at the age of 13 months. Moreover, the synovitis and macrophage accumulation were observed in the joints of 9-month-old R3cKO mice when the articular cartilage was not grossly destructed. FGFR3 deficiency in myeloid cells also aggravated joint destruction in DMM mouse model. Mechanically, FGFR3 deficiency promoted macrophage chemotaxis partly through activation of NF-κB/CXCR7 pathway. Inhibition of CXCR7 could significantly reverse FGFR3-deficiency-enhanced macrophage chemotaxis and the arthritic phenotype in R3cKO mice.ConclusionsOur study identifies the role of FGFR3 in synovial macrophage recruitment and synovitis, which provides a new insight into the pathological mechanisms of inflammation-related arthritis.

The interface characteristics of electrode materials are of tremendous value for supercapacitors, however, poor conductivity, instability in harsh reaction conditions and limited ion mobility in oxide materials are identified as immense challenges for generating high energy density without renouncing the power capability. Herein, a peculiar catalytic chemical vapour deposition (CCVD) approach is employed to decorate a very thin carbon capsules (CCs) on the surface of LiMn2O4 nanorods to synthesize a very active and uniformly distributed LiMn2O4/CCs nano-hybrid material with modified interface characteristics. The CCs not only provide the physicochemical protection as well as improve the electrical conductivity. As an electrode material, LiMn2O4/CCs possess the specific discharge capacitance of 451 F/g which is far superior to LiMn2O4 (304 F/g) at the current density of 0.5 A/g in 0.5 M Li2SO4 aqueous solution. In addition, the LiMn2O4/CCs exhibit an outstanding specific capacitance of 380 F/g even at a much higher current density of 8 A/g. Moreover, after 3000 charge and discharge cycles, LiMn2O4/CCs electrode retains nearly 95% of initial capacity, higher than that of spinel LiMn2O4 electrode which retains only 93%. This innovative technique can be adopted to construct a large variety of other nano-hybrid materials for consumer utilization in the field of supercapacitors.

Cartilage-hair hypoplasia (CHH) is an autosomal recessive metaphyseal chondrodysplasia characterized by bone dysplasia and many other highly variable features. The gene responsible for CHH is the RNA component of the mitochondrial RNA-processing endoribonuclease (RMRP) gene. Currently, the pathogenesis of osteochondrodysplasia and extraskeletal manifestations in CHH patients remains incompletely understood; in addition, there are no viable animal models for CHH. We generated an rmrp KO zebrafish model to study the developmental mechanisms of CHH. We found that rmrp is required for the patterning and shaping of pharyngeal arches. Rmrp mutation inhibits the intramembranous ossification of skull bones and promotes vertebrae ossification. The abnormalities of endochondral bone ossification are variable, depending on the degree of dysregulated chondrogenesis. Moreover, rmrp mutation inhibits cell proliferation and promotes apoptosis through dysregulating the expressions of cell-cycle- and apoptosis-related genes. We also demonstrate that rmrp mutation upregulates canonical Wnt/β-catenin signaling; the pharmacological inhibition of Wnt/β-catenin could partially alleviate the chondrodysplasia and increased vertebrae mineralization in rmrp mutants. Our study, by establishing a novel zebrafish model for CHH, partially reveals the underlying mechanism of CHH, hence deepening our understanding of the role of rmrp in skeleton development.

Achieving highly efficient Y3Al5O12:Ce3+ phosphor is desirable to fabricate bright white light-emitting diodes (wLED). Designing a synergistic effect of energy transfer from the guest materials to the host Y3Al5O12:Ce3+ is expected to favor the higher quantum efficiency of Y3Al5O12:Ce3+ phosphor. Here, we report a novel strategy to enhance the emission intensity and quantum efficiency of Y3Al5O12:Ce3+ phosphor by coating a thin g-C3N4 layer on the surface of Y3Al5O12: Ce3+ particles. Melamine was coated on the surface of Y3Al5O12: Ce3+ and heated at 580 °C to develop the g-C3N4 layer. The phase, microstructure, photoluminescent properties and thermal stability are investigated in detail. It is demonstrated that g-C3N4 coated Y3Al5O12: Ce3+ has been successfully achieved, which shows higher emission intensity and quantum efficiency than the uncoated sample. This is due to the strong excitation energy absorption of g-C3N4, which is then transferred to luminescent Ce3+ ions. The synergistic effect of g-C3N4 coating-host materials shows potential applications to improve the quantum efficiency of other phosphors.

The main objective of this paper is to reveal the mechanism of enhanced excitation light absorption in nano-pores structure BaMgAl10O17:Eu2+ (BAM) phosphor by optical analysis. The optical refractive index of the BAM was calculated from the reflectance spectra by Kramers–Kronig dispersion relation. And based on the effective medium theory, the anisotropic optical properties of porous BAM layer and its relations of absorption enhancement with porosity and thickness were investigated. A finite element simulation model was used for study the influence of pores size on optical properties. All the numerically evaluated results were match the experimental data.

Zirconium Boride is widely used as thermal protection materials. However, the characteristics of poor oxidation resistance of ZrB2 at high temperatures limits its applications. In order to improve the anti-oxidation performance of ZrB2, a novel method of doping LaF3 is adopted in present study. In the synthesis process of ZrB2 via carbothermal reduction method, LaF3 was introduced to the initial materials. Motivated by the slightly higher formation temperature of ZrB2 than the melting point of LaF3, a liquid glass phase composed of F and La was deposited on the surface of ZrB2, which naturally brought in oxygen starvation and contributed to improved oxidation resistance performance. The crystal lattice parameters and the anti-oxidation ability of ZrB2 are closely dependent on the added LaF3 content, which can ascribe to La3+/Zr2+ substitution and the amount of glass phase on the surface of ZrB2.

Most microwave absorbers lose their function under harsh working conditions, such as a high temperature and an oxidative environment. Here, we developed a heterogeneous ZrN0.4B0.6/SiC nanohybrid via combined catalytic chemical vapor deposition (CCVD) and chemical vapor infiltration (CVI) processes using ZrB2 as the starting material. The composition and structure of the ZrN0.4B0.6/SiC nanohybrid were controlled by tuning the CCVD and CVI parameters, such as reaction temperature, time, and reactant concentration. The optimal heterogeneous ZrN0.4B0.6/SiC nanohybrids were obtained initially by preparing ZrB2@C via the CCVD process at 650 °C for 30 min and the subsequent CVI at 1500 °C, where the ZrB2@C reacted with Si under N2. The ZrN0.4B0.6/SiC nanohybrid exhibited enhanced microwave absorption ability with a minimum reflection loss value of approximately -50.8 dB at 7.7 GHz, a thickness of ∼3.05 mm, and antioxidation features at a high temperature of 600 °C. The heterogeneous ZrN0.4B0.6/SiC nanohybrid possessed reasonable conductivity, leading to dielectric loss, whereas SiC nanofibers formed a three-dimensional network that brought higher dipole moments, whereas a small part of the ZrN0.4B0.6/SiC nanohybrid structure generated an effective interface for higher attenuation of microwaves. Therefore, these material features synergistically resulted in a well-defined Debye relaxation, Maxwell-Wagner relaxation, dipole polarization, and the quarter-wavelength cancellation, which accounted for the enhanced microwave absorption.