13 research outputs found

    Towards Personalized Federated Learning via Heterogeneous Model Reassembly

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    This paper focuses on addressing the practical yet challenging problem of model heterogeneity in federated learning, where clients possess models with different network structures. To track this problem, we propose a novel framework called pFedHR, which leverages heterogeneous model reassembly to achieve personalized federated learning. In particular, we approach the problem of heterogeneous model personalization as a model-matching optimization task on the server side. Moreover, pFedHR automatically and dynamically generates informative and diverse personalized candidates with minimal human intervention. Furthermore, our proposed heterogeneous model reassembly technique mitigates the adverse impact introduced by using public data with different distributions from the client data to a certain extent. Experimental results demonstrate that pFedHR outperforms baselines on three datasets under both IID and Non-IID settings. Additionally, pFedHR effectively reduces the adverse impact of using different public data and dynamically generates diverse personalized models in an automated manner

    Three-dimensionally printed porous biomimetic composite for sustained release of recombinant human bone morphogenetic protein 9 to promote osteointegration

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    Three-dimensionally printed porous titanium alloys prepared using the electron beam melting (EBM) technology have customized structures and a low elastic modulus. They can promote the repair of bone defects. Growth factors can enhance the biological activity of plants in vivo, and bone morphogenetic protein 9 (BMP9) is the key factor for osteogenesis. The purpose of this study was to evaluate a porous titanium implant prepared using the EBM technology with temperature-sensitive collagen mixed with recombinant human (rh) BMP9 as a composite scaffold to be continuously provided to enhance osteogenesis in rabbit femoral defects. The in vitro experiments verified cell proliferation, proliferation and application of the composite stent, the degree of release of temperature-sensitive collagen to rhBMP9, and the osteogenesis-inducing effect of the composite stent on bone marrow mesenchymal stem cells. In vivo, the rabbit femoral defect model was used to evaluate the effects of the composite on osteointegration and bone ingrowth. The results showed that the composite scaffold had good biocompatibility and provided bioactive growth factors for bone repair. Further, the release of rhBMP9 significantly enhanced osteogenesis in and around the porous scaffolds. This method helps to study bioactive coating on the titanium alloy surface of patients with bone defects

    Fluorine, chlorine, and gallium co-doped zinc oxide transparent conductive films fabricated using the sol-gel spin method

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    Transparent conductive films (TCFs) are crucial components of solar cells. In this study, F, Cl, and Ga co-doped ZnO (FCGZO) TCFs were deposited onto a glass substrate using the sol-gel spin-coating method and rapid thermal annealing. The effects of F-doping content on the structural, morphological, electrical, and optical properties of FCGZO films were examined by XRD, TEM, FE-SEM, PL spectroscopy, XPS, Hall effects testing, and UV–vis–NIR spectroscopy. All prepared ZnO films exhibited a hexagonal wurtzite structure and preferentially grew along the c axis perpendicular to the substrate. Changes in the doping concentration of F changed the interplanar crystal spacing and O vacancies in the film. At a doping ratio of 2% (in mole), the F, Cl, and Ga co-doped ZnO film exhibited the best photoelectric performance, with a carrier concentration of 2.62 × 1020 cm−3, mobility of 14.56 cm2/(V·s), and resistivity of 1.64 × 10−3 Ω·cm. The average transmittance (AT) in the 380–1 600 nm region nearly 90% with air as the reference, and the optical band gap was 3.52 eV

    Low frequency and broadband metamaterial absorber with cross arrays and a flaked iron powder magnetic composite

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    In this paper, we present a design, simulation and experimental measurement of a cross array metamaterial absorber (MMA) based on the flaked Carbonyl iron powder (CIP) filled rubber plate in the microwave regime. The metamaterial absorber is a layered structure consisting of multilayer periodic cross electric resonators, magnetic rubber plate and the ground metal plate. The MMA exhibits dual band absorbing property and the absorption can be tuned from 1∼8GHz in the same thickness depending on the dimension and position of the cross arrays. The obviously broadened absorbing band of the designed structure is a result of the synergistic effects of the electrical resonance of the cross arrays and intrinsic absorption of the magnetic layer. The polarization and oblique incident angle in TE and TM model are also investigated in detail to explore the absorbing mechanisms. The resonance current of the cross array can excite the enhanced local magnetic field and dielectric field which can promote the absorption. The measurement results are basically consistent with the simulations but the absorbing peaks move a little bit to higher frequency for the reason that the surface oxidation of the flaked CIP in the preparation process

    Enantioselective Synthesis of Amino Acids by Photocatalytic Reduction of CO2 on Chiral Mesostructured ZnS

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    Reduction and fixation of CO2 in natural systems via solar energy generates diverse products, ranging from small molecules to biomolecules. To date, only a few multicarbon species have been obtained by artificial CO2 photoreduction1-5, especially abiotic photosynthesis of biomolecules with various functional groups, which has long been a fundamental yet challenging issue. Herein, we report the photocatalytic synthesis of amino acids from CO2 and NH3 on a chiral mesostructured ZnS (CMZ) nanosphere, which is constructed by arrays of chiral nanorods. Serine (Ser) is the main component of various amino acids, with an enantiomeric excess (ee) greater than 96% and a total yield of over 30 μmol gcat-1. The Ser formation pathway could be accessed through *OCCO intermediates due to C-C coupling, as demonstrated by experimental data. Chiral-induced spin polarization of CMZ has been speculated to facilitate the separation of photogenerated carriers and the production of stable triplet OCCO. Different activation energies of reduction reactions driven by the spin-polarized electrons in CMZ lead to the formation of enantiomeric amino acids. Our findings will inspire new perspectives in catalytic theory and the formation of chiral biomolecules in artificial synthesis and nature
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