The Haversian system is one of the most important pathways to repair bone defects, and it is the basic guarantee for the repair of bone defects, which means that the formation of the Haversian system ...indicates repairing of the defects. The integration of structure and function for tissue engineering scaffolds is of great importance in mimicking native bone tissue. However, in contrast to the increasing demands, how to rapidly prepare various sizes of such Haversian system mimicking scaffolds in batch becomes a major challenge. In this study, we designed three types of platforms with different sizes in combination with the freeze-drying approach. Chitosan/type I collagen composite materials were used to study the structure, morphology, and performance of the production, and the effects of the controlled architecture on osteogenesis. Results showed that the physicochemical effects of the mass fabricated scaffolds of various sizes met the requirements of bone repair materials. In addition, the scaffolds had good cytocompatibility and excellent
in vivo
bone repair performance, which have potential clinical applications.
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•PAs-Cu2+ modified chitin sponges could catalyze S-nitrosothiols to generate NO.•The sponges with antioxidant properties could protect cells from ROS injury.•The sponges exhibited ...antibacterial and pro-vascularization properties.•The sponges could accelerate wound healing and inhibit scar formation.
Bacterial overgrowth and high oxidative stress often lead to burn wound infection, hyper-inflammation, and slowed wound healing, eventually causing scar formation. Wound dressings synergized with antibacterial, antioxidant, and pro-vascularization activities can effectively promote wound healing and inhibit scars formation. Herein, chitin sponge consisted of chitin fibers was modified by the coating of proanthocyanidins (PAs) – Cu2+ for effective scarless skin regeneration in a burn injury. The physicochemical characteristics indicated that PAs and Cu2+ successfully modified chitin sponges by the coordination between PAs and Cu2+. For one thing, PAs improved the antioxidant performance of sponges, and for another, with the help of PAs, Cu2+ effectively catalyzed S-nitrosothiols (RSNOs) to continuously generate nitric oxide (NO) in vitro/vivo for improving the inhibition of microorganisms and pro-vascularization activities. Also, Ch/PAs-Cu promoted proliferation of human umbilical vein endothelial cells (HUVECs) and rat fibroblasts (NIH-3T3), and the expression of angiogenic-related cytokines VEGF, eNOS, FGF, and MMP9. In animal experiments, Ch/PAs-Cu inhibited the accumulation of macrophages and neutrophils to regulate wound inflammation while up-regulating the expression of CD31 and α-SMA cytokines to promote angiogenesis. Ultimately, it promoted wound healing and inhibited scar formation. Therefore, Ch/PAs-Cu may be a promising dressing for the scarless repair of burned skin.
•The nanoporous chitosan/lanthanum hydroxide aerogel beads were fabricated.•The achieved aerogel beads had high surface area and pore volume.•The aerogel beads possess excellent adsorption capacity ...for phosphorus.
In this study, chitosan and lanthanum hydroxide composite aerogel beads were prepared for phosphorus adsorption via co precipitation and supercritical carbon dioxide drying technique. The porous structure of composite aerogel beads was investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) measurements. The results showed that the aerogel bead with mass ratio of chitosan to lanthanum chloride 100:50 exhibited a larger surface area of 172.74 m2/g and a pore volume of 1.05 cm3/g, respectively. Also the phosphorus adsorption kinetics of the aerogel bead showed a faster adsorption rate and the larger adsorption capacity (148.33 mg/g) for phosphorus. In addition, adsorption kinetics model analysis showed that the phosphorus adsorption process fitted both pseudo-first order and pseudo-second order kinetic model.
Bacterial infection is seriously threatening human health, and the design of high-efficiency and good biocompatibility antibacterial agents is an urgent problem to be solved. However, with the ...emergence of drug-resistant bacteria, the existing antibacterial agents have low killing efficiency, and the formation of biofilms has further weakened the therapeutic effect. Herein, we constructed an efficient antibacterial system mediated by near-infrared light for synergistic antibacterial and biofilm dissipation. Specifically, the ZnO/Ti3C2T x with heterojunction was synthesized by hydrothermal growth of ZnO on the surface of lamellar Ti3C2T x -MXene. The prepared ZnO/Ti3C2T x had better photothermal ability than ZnO and Ti3C2T x , respectively. The local thermal effect can not only destroy the integrity of the bacterial membrane but also promote the release of Zn2+ ions and further improve the antibacterial performance. ZnO/Ti3C2T x achieved a 100% sterilization rate (better than either ZnO or Ti3C2T x ) at 150 μg mL–1. The biofilm dissipation experiment further proved its excellent biofilm ablation effect. More importantly, the results of in vitro cell culture and animal experiments have demonstrated its good biological safety. In summary, this new type of nanomaterial shows strong local chemical photothermal sterilization ability and has great potential to replace traditional antibacterial agents.
Joint chance constraint (JCC) is a significant way to guarantee the spinning reserve in multi-area power systems with renewable energy (MAS-RE). This paper presents a novel p -efficient point (PEP) ...method to deal with the JCCs of unit commitment (UC) problems to guarantee the spinning reserve at the given confidence level. In the p -efficient point method, the p -efficient points are used to obtain the minimum spinning reserve requirement to satisfy the given confidence level. Based on p -efficient points, the intractable JCCs can be converted into tractable deterministic constraints directly, which avoids the complicated calculations and approximation errors of JCCs. Furthermore, an optimal mathematical programming is formulated to directly obtain p -efficient points, without assumptions on the probability distribution function (PDF) of wind power. Besides, in this paper, the applicability of the p -efficient point method is extended from positive space to both positive and negative space. Simulation results demonstrate that the proposed approach has better performances in scheduling spinning reserve than the popular Sample Average Approximation (SAA), Partial Sample Average Approximation (PSAA) and the Kernel Density Estimation (KDE) combined with Boole's inequality.
UV-curable hyperbranched polyurethane (UV-HBPU) containing carboxyl groups was synthesized from isophorone diisocyanate (IPDI), diethanolamine (DEOA), polyethylene glycol (PEG-400), hydroxyethyl ...acrylate (HEA), and 2,2-bis (hydroxymethyl) propionic acid (DMPA). The UV-HBPU was used as a negative-type photoresist for a printed circuit board (PCB). Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1HNMR) spectroscopy of UV-HBPUs indicated that the synthesis was successful. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the thermal stability of the UV-HBPUs decreased as the HEA content increased. The polymer exhibited excellent photoresist properties, and the resolution of circuits based on this negative-type photoresist reached 10 μm.
Abstract
Logistics supply chain (LSC), a chain structure that integrates and coordinates all logistics transactions, has become an essential component of the modern logistics industry. By using ...blockchain, trusted logistics services enable participants to effectively record and track transactions during the logistics process. Current blockchain‐based LSC features distributed structure and data privacy requirements, hindering the supervision of logistics transactions. Leveraging emerging dual‐blockchain architecture to separate logistics transactions from supervision is a promising direction. However, the dual‐blockchain collaboration restricts supervision due to its cross‐chain privacy and efficiency. To address these issues, a logistics supply chain supervision scheme based on dual‐blockchain collaboration (DBC) is proposed. First, an independent supervision blockchain is constructed to balance the contradiction between distributed structure and supervision requirements. Second, two mechanisms are designed to enhance the privacy and performance of collaborative supervision. The hybrid access control mechanism enables fine‐grained supervision for different participants, and the aggregated transaction verification method supports efficient collaboration for logistics transactions. Security analysis and performance evaluation demonstrate the feasibility of DBC in enhancing the security and supervision of logistics data on the dual‐blockchain architecture. Experimental results show that the cross‐chain supervision overhead of DBC is reduced to of the baseline schemes.
The privacy-preserving query is critical for modern blockchain systems, especially when supporting many crucial applications such as finance and healthcare. Recent advances in blockchain query ...schemes mainly focus on enhancing the traceability efficiency of integrity authentication. Despite these efforts, we argue that the exposure of retrieval information may result in privacy leakage, which inevitably poses an important yet unresolved challenge. In this paper, we introduce Cloak, a novel privacy-preserving blockchain query scheme with two notable features. First, it utilizes a two-phase distributed query requests technique, i.e., division and aggregation, to hide retrieval information based on the natural independent characteristic of blockchain. Second, we add noise to the sub-request set to avoid malicious attacks during transmission and adopt smart contract-based asymmetric encryption to guarantee the correctness of query results. Experimental results demonstrate that Cloak improves the query performance by up to 4× and reduces the storage overhead by 50% compared with the state-of-the-art Spiral.
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•The synthesized polyimides with double bond end groups showed an outstanding solubility, and possessed excellent solution processability.•The synthesized polyimides could be used to ...prepare UV-curable coatings.•The UV cured coatings exhibited excellent performances, such as favorable thermal stability, higher optical transparency and lower moisture uptakes.
The fluorinated polyimides with double bond end groups (G-FPIs) based on 4,4′-(hexafluoroisopropylidene) diphthalic anhydride, 4,4′-(hexafluoroisopropylidene) dianiline, 4-aminobenzoic acid and glycidyl methacrylate were synthesized via a typical two-step imidization method. The structure and properties of G-FPIs were characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1HNMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). It was determined that all G-FPIs were the amorphous phase and easily soluble in many polar organic solvents, and the G-FPIs had high glass-transition temperature (Tg). Then, UV-curable coatings were prepared from G-FPIs, and the properties were evaluated by real-time fourier transform infrared (RTIR), thermogravimetric analysis (TGA), UV–vis spectroscopy, water contact angle and water absorption test. Results showed that these coatings possessed favorable double bond conversion, excellent thermal stability, higher optical transparency and lower moisture uptakes. Moreover, the coatings exhibited good hardness and excellent gloss. Due to the outstanding combination properties, these UV-cured coatings based on G-FPIs could be considered as potential candidates for photoelectric, microelectronic and aerospace materials.
Geomagnetic Fingerprint Maps for Indoor Positioning Xiaolong Xu; Licheng Lin
2017 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery (CyberC),
2017-Oct.
Conference Proceeding
Indoor positioning technology is becoming the hot spot of the current research. How to choose a suitable positioning scheme is particularly important. This paper focuses on the geomagnetic field, and ...geomagnetic fingerprint maps for indoor location. The methods of constructing geomagnetic fingerprint map are verified via experiments. Experimental results show that the accuracy of the scheme which uses the magnetic field strength values of special landmarks is not enough to constructing efficient geomagnetic fingerprint maps. The method of combining the magnetic field strength value with the path can not only solves the numerical difference caused by the microelectronic mechanical systems sensor effectively, but also has high positioning accuracy. At the same time, it is feasible to use the idea of group intelligence to construct a geomagnetic fingerprint map. We make the corresponding summary to the second scheme, which needs to be further optimized on the original basis so that it can be truly applied to real lives. This paper analyzes the information of the geomagnetic field, compares the schemes of constructing the geomagnetic fingerprint map via experiments, and promote the further development of geomagnetic field in indoor positioning technology.
