Search

Poor wound healing is a very common clinical problem, so far there is no completely satisfactory treatment. Electropsun nanofibrous wound dressings may provide an ideal structure to improve wound healing. Therefore, development of nanofibrous wound dressings with rapid hemostasis, antibacterial and tissue regenerative multi-functions has been a hotspot in the field of skin tissue engineering. In this work, polydopamine (PDA) and polypyrrole (PPy) were uniformly coated onto the surface of poly(l-lactide) (PLLA) nanofibers by in-situ polymerization, forming a novel PPy/PDA/PLLA three-layer core-shell structure. The homogeneously coated PPy and PDA two layers could significantly increase the hydrophilicity, conductivity, near-infrared photothermal antibacterial property, the speed of wound hemostasis, antioxidant capacity and reactive oxygen species (ROS) scavenging capacity, respectively. In addition, PPy/PDA/PLLA nanofibers showed good biocompatibility. Rat wound healing model confirmed that PPy/PDA/PLLA nanofibers could significantly accelerate wound repair in vivo. Thus, this novel nanofibrous wound dressing is a promising candidate for clinical wound healing.

Graphite, whose presence is harmful to the mechanical property, is one of the main reaction products between Ni-based alloy and SiC. This paper reports a method of eliminating graphite based on thermodynamic calculations. Different amounts of Si powders are added into the Inconel 625 powder filler to adjust the interfacial reactions during the brazing process. When the Si content in the liquid reaches the theoretically calculated value, the reactions between the Inconel 625 filler and SiC substrate are suppressed, and no graphite forms on the interface. The graphite-free SiC joints show good oxidation resistance. The joint's strength maintains at 25.7 MPa while that with graphite drastically drops to 5.5 MPa after 185 h oxidation in air. The reaction products and oxidation process of the SiC joints are also carefully analyzed in this paper.

In this work, we successfully synthesize the core-shell structure carbon@titanium dioxide (C@TiO2) composite microspheres with wrinkled surface through a three-step method and build up the relationship between the TiO2 layer thickness and the microwave absorption property. The absorbing mechanism of the novel microsphere is revealed. Interface polymerization is applied for preparation of wrinkled poly glycidyl methacrylate/divinylbenzene polymer microspheres (PGMA/PDVB); Then, TiO2 layer is controllably coated on the surface of PGMA/PDVB microspheres by hydrolysis of tetrabutyl titanate (TBT); C@TiO2 composite microspheres are obtained by vacuum carbonization with PGMA/PDVB@TiO2 microspheres as the precursor. TiO2 layer thickness on the surface of C@TiO2 composite microspheres can be effectively adjusted by controlling the amount of TBT. When the amount of TBT is 0.75 mL, C@TiO2 composite microspheres exhibit the outstanding electromagnetic loss performance. The maximum reflection loss value (RLmax) reaches -49.21 dB at the thickness of 2 mm, corresponding effective absorption bandwidth is 5.27 GHz. The maximum effective absorption bandwidth is 5.5 GHz at 2.2 mm. The results show that the introduction of TiO2 can regulate electromagnetic parameters and enhance interface polarization ability. Meanwhile, the surface wrinkle structure offers more opportunities for multiple reflections of electromagnetic and introduces a large number of defective skeleton structure. The synergy of multiple advantages makes the absorbing performance of C@TiO2 composite microspheres significantly improved. This work plays a guiding role for the composition and the structure optimization of existing microwave absorbers.

In this work, we develop a novel synthetic strategy for wrinkled magnetic composite microspheres (Fe3O4@C). Firstly, hydrophobic oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles acted as the magnetic component are prepared by synchronous modification coprecipitation method. The macromolecular emulsifier with initiating activity is obtained by means of soap-free emulsion polymerization under the presence of 1,1-diphenylethylene (DPE). Then, interfacial polymerization is employed to synthesis Fe3O4@polymethylglycidyl ester/divinylbenzene composite microspheres (Fe3O4@PGMA/DVB). Fe3O4@C composite microspheres are obtained by vacuum carbonization of the microspheres. The effect of magnetic content on the microwave absorbing properties of Fe3O4@C composite microspheres is explored. The results show that Fe3O4@C composite microspheres exhibit the excellent application performance at the Fe3O4 content of 0.15 g. The reflection loss can reach −53.7 dB at only thickness of 1.7 mm. The Maximum effective absorption bandwidth is up to 5.26 GHz with a thickness of 1.9 mm. The microwave attenuation mechanism of Fe3O4@C composite microspheres is revealed. The excellent absorbing performance is attributed to the enhanced interfacial polarization ability, the surface wrinkled structure and the good synergy between dielectric and magnetic losses. This work provides an effective strategy for the design and preparation of new magnetic composite materials.

Ni-based alloys are believed to be the most suitable brazing fillers for SiC ceramic application in a nuclear environment. However, graphite, which severely deteriorates the mechanical property of the joint, is inevitable when Ni reacts with SiC. In this paper, Different amounts of Zr powders are mixed with Inconel 625 powders to braze SiC at 1400 °C. When Zr addition reaches 40 wt%, the brazed seam confirms the absence of graphite. This research proves that Zr can avoid the graphite’s formation by suppressing Ni’s activity. The room-temperature shear strength of the joint with graphite’s absence is tested to be 81.97 MPa, which is almost three times higher than that of the joint with graphite. The interfacial reaction process and mechanism of the SiC joint are investigated and explained in this paper using thermodynamic calculations.

In recent years, carbon materials derived from metal-organic frameworks (MOFs) have attracted much attention in the field of microwave absorption. It is challenging to prepare composite absorbers with a controllable binary MOF-on-MOF heterostructure. Here, we construct two binary hybrid MOF heterostructures through selective assembly strategies, and realizes their conversion to magnetic porous carbon materials through a simple carbonization process. The special hybrid structure of hexagonal pyramid column and octahedron depends on the selective growth of the guest MOF on the specific crystal facet of the host MOF. The microwave absorbing properties of carbonized UIO-66@Co-doped MIL-88B (UM) and DUT-52@Co-doped MIL-88B (DM) are systematically studied. The selectively combined heterogeneous components endow the absorber with hierarchical pore structures, optimal impedance matching and excellent electromagnetic attenuation capabilities. The products carbonized at 700 °C (UM-700 and DM-700) exhibit superior microwave absorbing properties. It is worth noting that only with a matching thickness of 2 mm, the minimum reflection loss (RLmin) of DM-700 exceeds −65.2 dB, and the effective absorption bandwidth (EAB, RL

： In this paper, two dimensional Ti3C2Tx MXene nanosheets and one-dimensional Ni nanochains are successfully assembled into three dimensional porous MXene/Ni composite microspheres by ultrasonic spray. Their unique micro nano structure and well-designed three-dimensional porous interconnection network can significantly improve the stacking of Ti3C2Tx MXene nanosheets and the agglomeration of magnetic Ni nanochains. By changing the content of Ni nanochains，we can obtain MXene/Ni composite microspheres with different magnetic content. Due to the difference in conductivity between Ti3C2Tx MXene and Ni, as well as the newly generated hetero interface and abundant surface groups, MXene/Ni composite microspheres show good impedance matching and excellent electromagnetic wave absorption performance. The minimum reflection loss (RLmin) is −52.7 dB@12.8 GHz, and the corresponding matching thickness is only 1.9 mm. The preparation of MXene/Ni composite microspheres provides a simple and effective method for designing other MXene-based composite materials.

In this paper, the interfacial reaction is investigated by joining SiC ceramic with Inconel 625 superalloy interlayer at different temperatures. CALPHAD method is used based on a Ni-Cr-Si ternary thermodynamic database to analyze the reactions between the Inconel 625 superalloy and the SiC ceramic. It is found that when the liquid alloy reaches a specific composition, the reactions between them stop. An equilibrium is established between the liquid alloy and SiC during the joining process, regardless of the temperature change. Furthermore, thermodynamic predictions of the reaction products are proved right by EBSD and XRD analysis. This work demonstrates that CALPHAD is a suitable method for effectively investigating the complex reaction system and further promoting precise theoretical analysis.

Colloidal gold nanoparticles (AuNPs) have been used in high technology applications due to their optical and electronic properties. Unfortunately, these broader applications are severely hampered by their agglomeration tendency and instability. Therefore, in this study, highly stable and aggregation resistant AuNPs were synthesized using Kappa carrageenan (κ-car) media (as a reducing and stabilizing agent) by a green synthesis protocol. The effect of different factors of reaction such as the concentration of κ-car (Cκ-car %), reaction time (t), temperature (T), and solution pH (here after simply define to ‘reaction parameters’) was studied by one-variable-at-a-time technique to optimize the yield production of AuNPs. The characterization of AuNPs synthesized at optimum conditions revealed that the particles are spherical in shapes, smaller in size (13.5 ± 5.1 nm) with a narrow distribution, highly crystalline (d-spacing = 0.230 nm) in nature, well stabilized (zeta potential = −22.1 mV) by coating by a thin layer of κ-car carbohydrate. The synthesized AuNPs reveal excellent catalytic function in the degradation (up to 99%) of azo-dyes. The kinetics study in the degradation reaction revealed that the technique could be extended to real wastewater treatment applications.

To investigate the reaction mechanism of Ni/SiC system, 0.1 μm-thick pure nickel foil is used to join SiC ceramic at 1245 °C for different times. Interfacial melting is calculated to occur at 964 °C along the interface due to the low eutectic point of θ-Ni2Si and NiSi, a periodical layered structure, consisting alternating layers of silicides/silicides+graphite, is formed along the interface due to periodical detachment of graphite from SiC reaction interface during the reactions between Ni-Si liquid phase and SiC. The reaction products of Ni/SiC are successfully predicted by CALPHAD method, based on a home-made Ni-Si-C ternary database. The reaction processes between Ni and SiC and the morphology changes of the joined seam are discussed in detail in this paper. The average shear strengths of SiC joints held for 15 min, 30 min and 60 min are tested to be 16.53 MPa, 19.32 MPa and 29.43 MPa, respectively.

Sine oculis homeobox 1 (SIX1), a key transcription factor for regulating aerobic glycolysis, participates in the occurrence of various cancer types. However, the role of SIX1 in melanoma and the upstream regulating mechanisms of SIX1 remain to be further investigated. MicroRNAs (miRNAs) have emerged as key regulators in tumorigenesis and progression. Here, we show that miR-489-3p suppresses SIX1 expression by directly targeting its 3′ untranslated region (3′ UTR) in melanoma cells. miR-489-3p suppressed melanoma cell proliferation, migration, and invasion through inhibition of SIX1. Mechanistically, by targeting SIX1, miR-489-3p dampens glycolysis, with decreased glucose uptake, lactate production, ATP generation, and extracellular acidification rate (ECAR), as well as an increased oxygen consumption rate (OCR). Importantly, glycolysis regulated by the miR-489-3p/SIX1 axis is critical for its regulation of melanoma growth and metastasis both in vitro and in vivo. In melanoma patients, miR-489-3p expression is negatively correlated with SIX1 expression. In addition, patients who had increased glucose uptake in tumors and with metastasis assessed by positron emission tomography (PET) scans showed decreased miR-489-3p expression and increased expression of SIX1. Collectively, our study demonstrates the importance of the miR-489-3p/SIX1 axis in melanoma, which can be a potential and a promising therapeutic target in melanoma., Graphical Abstract

Different sampling parameters have a great effect on the results of vibration assisted biopsy insertion process. Further analysis of the influence degree and rule of each sampling parameter on a single target variable to obtain the optimal parameter combination is essential for guiding clinical application. In this study, vibration assisted insertion experiments were conducted using gel phantom as experimental material. The effect degree of insertion velocity, vibration frequency, needle diameter and tip surface number on the maximum insertion force and fiction force was researched through orthogonal tests. The experimental results were analyzed by the combination of extreme deviation analysis and variance analysis. Single-objective optimization of different insertion process parameters was carried out to obtain an optimal combination of parameters and the influence degree of each test factor on each index. The experiment results show that according to the degree of effect, the sampling parameters affecting the maximum insertion force from large to small are insertion velocity, needle diameter, vibration frequency and the number of the needle tip surface. The affecting the friction from large to small are insertion velocity, needle diameter, number of the needle tip surface and vibration frequency. The verification experiment result show that optimal parameter combination is reasonable in a certain range.

Circular RNAs (circRNAs), resulting from the non-canonical splicing of linear pre-mRNAs, have permanently altered our perspectives toward cancer recently, especially in carcinogenesis and cancer progression. However, the roles of circRNAs in esophageal squamous cell carcinoma (ESCC) remain largely unknown. In the current study, circRNAs expression profiles are screened in ESCC, using plasma samples from 10 ESCC patients, including different TNM stages and 5 normal controls. Characteristics of circRNAs including length, types, and the possibility of binding to proteins are analyzed. Candidate tumor-related circRNAs are then quantitated in ESCC tissues, plasmas and cell lines. ESCC tissues can secret circRNAs into plasma and patients with high plasma circ-SLC7A5 are associated with high TNM stage, tending to have shorter overall survival than those with high levels. In addition, the biological characteristics of circ-SLC7A5 including location, miRNAs binding, m6A modification were analyzed. Our study reveals a novel prognosis biomarker of circ-SLC7A5, providing a preliminary landscape of circRNA expression for detection of ESCC.

In this study, natural pyrite (NP) was used to activate peroxydisulfate (PDS) for imidacloprid (IMD) degradation. NP was characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Effects of key reaction parameters (NP dosage, PDS concentration and initial pH) and co-existing ions on IMD degradation in the NP/PDS system were investigated. Quenching experiments and electron spin resonance (ESR) tests identified the existence of sulfate radical (SO

Arbuscular mycorrhizal (AM) fungi play an important role in facilitating ecosystem function and stability. Yet, their community response patterns and ecological assembly processes along elevational gradients which cross a range of climates and soil conditions remain elusive. We used Illumina MiSeq sequencing to examine trends in soil AM fungal community along an elevational gradient from 100 m to 2300 m in central Japan. A total of 750 operational taxonomic units (OTUs) affiliated to 12 AM fungal genera were identified from soil samples, and the AM fungal community composition differed strongly with elevation, with variance explained more by climate, followed by soil and plant factors. The AM fungal α-diversity, network connectivity and complexity between AM fungal taxa and also with plant communities all exhibited a maximum at the mid-elevation of 800 m and then declined, principally influenced by soil pH and precipitation. Stochastic processes dominated AM fungal community assembly across the whole elevation gradient, with homogenizing dispersal being the main process. Only when AM fungal communities were contrasted across a relatively broad range of elevations, did variable selection (deterministic process) became significant, and even then in a mixed role with stochasticity. While OTUs of AM fungi are clearly adapted to particular environmental ranges, stochasticity due to rapid dispersal has a major role in determining their occurrence, suggesting that AM fungi may possess generalized and interchangeable niches, and can adjust their distribution rapidly - at least on the scale of a single mountain. This finding emphasizes that the roles of AM fungi in plant ecology may be non-specific and easily substituted, and furthermore that there is rapid local scale dispersal, which may allow plants to maintain effective AM associations under environmental change.

Identification of regional collision risk in water area is of significance for the safety of navigation. However, traditional risk identification models are subject to the limitations in accuracy, short-term identification and traffic characteristics. Herein, a framework was put forward to identify regional collision risk instantaneously based on AIS data. The vessels were clustered by using the spatial clustering method. Afterwards, the framework was divided into two steps. Firstly, collision risk of each cluster was obtained by collision risk and contribution of the vessels within the cluster. An analytical method was adopted to identify collision risk of each vessel from the perspective of vessel pairs. Contribution of each vessel was determined by using improved Shapley value method in game theory. Secondly, regional collision risk was obtained by collision risk and contribution of each cluster. Case studies were carried out based on the AIS data of Northern Yellow Sea in China to validate the validity of the proposed framework. The results show that the proposed framework can effectively identify collision risk in water area, presenting the potential for collision risk monitoring and collision risk analysis of water area.