65 research outputs found

    Stable Photochromism and Controllable Reduction Properties of Surfactant-Encapsulated Polyoxometalate/Silica Hybrid Films

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    In this paper, we present a novel strategy for fabricating polyoxometalate (POM)-based photochromic silica hybrid films. To combine metal nanoparticles (NPs) into the POMs embedded silica matrix, furthermore, we realized the controllable in situ synthesis of metal NPs in the film by utilizing the reduction property of POMs existing in the reduced state. Through electrostatic encapsulation with hydroxyl-terminated surfactants, the POMs with good redox property can be covalently grafted onto a silica matrix by means of a sol−gel approach, and stable silica sol−gel thin films containing surfactant-encapsulated POMs can be obtained. The functional hybrid film exhibits both the transparent and easily processible properties of silica matrix and the stable and reversible photochromism of POMs. In addition, well-dispersed POMs in a hydrophobic microenvironment within the hybrid film can be used as reductants for the in situ synthesis of metal NPs. More significantly, the size and location of NPs can be tuned by controlling the adsorption time of metal ions and mask blocking the surface. The hybrid film containing both POMs and metal NPs with patterned morphology can be obtained, which has potential applications in optical display, memory, catalysis, microelectronic devices and antibacterial materials

    Self-Assembled Multibilayers of Europium Alkanoates:  Structure, Photophysics, and Mesomorphic Behavior

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    A series of europium alkanoates (Cn-1H2n-1CO2)3Eu, (n = 14, 16, 18, 20) have been synthesized and characterized in detail. X-ray diffraction and Fourier transform infrared spectroscopic measurements confirm the multibilayer structure of these homologues. In such bilayers, the europium ionic layers are well separated by the highly ordered alkyl chains which are in an all-trans conformation and perpendicular to both sides of the europium ionic layers. There is a mixed-coordination type of chelating bidentate and bridging bidentate between the carboxylate groups and the europium ions. All samples exhibit characteristic emission of europium, though the luminescent intensity has been partly quenched by the carboxylate groups. Differential scanning calorimetry (DSC) shows multiple melting points for these homologues, and temperature-dependent X-ray diffraction measurements also confirm the existence of the mesophase on heating. This mesophase is not truly liquid crystalline, but is similar to the smectic A phase of organic rodlike molecules. Meanwhile, it seems that with increasing atomic number of lanthanide ions, longer alkyl chains will be required to form such a mesophase for the corresponding lanthanide alkanoates

    Polyoxometalate-Based Vesicle and Its Honeycomb Architectures on Solid Surfaces

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    The introduction of cationic surfactant DODA as counterions of [Eu(H2O)2SiW11O39]5- can form a mesoscopic supramolecular assembly of (DODA)4H[Eu(H2O)2SiW11O39], which aggregates into vesicles in chloroform. This POM-based vesicle can be further transferred into three-dimensional microporous architectures under moist air. The present methodology shows that, by combining inorganic chemistry and colloidal surface chemistry, a sequential self-assembling approach based on a series of linkable preorganized building blocks allows access to the fabrication of technological applicably POM-based microsized patterns, alternated with the soft lithographic method

    Self-Organized Microporous Structures Based on Surfactant-Encapsulated Polyoxometalate Complexes

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    Self-organized microporous structures based on a series of surfactant-encapsulated polyoxometalate complexes (SECs) have been prepared by using ordered condensed droplets as a template. Among these structures, ordered honeycomb structures were obtained and characterized in detail by taking (DODA)12H[Eu(SiW11O39)2] (SEC-1) as an example. Optical microscope, atomic force microscopic, and scanning electron microscopic measurements confirmed the formation of three-dimensional microporous structure, in which the top surface shows a highly ordered honeycomb structure. As compared to common solvent-casting films, the corresponding honeycomb films are more hydrophobic and possess more ordered lamellar structures. Both the wettability and the size of SECs exert significant influence on the formation of microporous structures. The proper hydrophobicity of SECs was proposed to be an essential factor for the formation of honeycomb films, and large-sized SECs are favorable for the fabrication of highly ordered honeycomb structures. The conditions for the formation of different surface morphologies have been discussed in terms of the contact angle of SECs at the interface between water and chloroform, and a contact angle slightly greater than 90° is found to be a prerequisite for the formation of honeycomb structures. The results reported in this paper not only help to further comprehend the mechanism of the formation of honeycomb structures, but also provide some guidance for the design of ordered microporous films based on organic/inorganic hybrid materials, exemplified by the organic/nanoparticle complexes

    DataSheet_1_Novel Insights Into Gene Signatures and Their Correlation With Immune Infiltration of Peripheral Blood Mononuclear Cells in Behcet’s Disease.pdf

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    BackgroundBehcet’s disease (BD) is a chronic inflammatory disease that involves systemic vasculitis and mainly manifests as oral and genital ulcers, uveitis, and skin damage as the first clinical symptoms, leading to gastrointestinal, aortic, or even neural deterioration. There is an urgent need for effective gene signatures for BD’s early diagnosis and elucidation of its underlying etiology.MethodsWe identified 82 differentially expressed genes (DEGs) in BD cases compared with healthy controls (HC) after combining two Gene Expression Omnibus datasets. We performed pathway analyses on these DEGs and constructed a gene co-expression network and its correlation with clinical traits. Hub genes were identified using a protein–protein interaction network. We manually selected CCL4 as a central hub gene, and gene-set enrichment and immune cell subset analyses were applied on patients in high- and low-CCL4 expression groups. Meanwhile, we validated the diagnostic value of hub genes in differentiating BD patients from HC in peripheral blood mononuclear cells using real-time PCR.ResultsTwelve hub genes were identified, and we validated the upregulation of CCL4 and the downregulation of NPY2R mRNA expression. Higher expression of CCL4 was accompanied by larger fractions of CD8 + T cells, natural killer cells, M1 macrophages, and activated mast cells. Receiver operator characteristic curves showed good discrimination between cases and controls based on the expression of these genes.ConclusionCCL4 and NPY2R could be diagnostic biomarkers for BD that reveal inflammatory status and predict vascular involvement in BD, respectively.</p

    DataSheet_1_Early Expression of Functional Markers on CD4+ T Cells Predicts Outcomes in ICU Patients With Sepsis.zip

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    ObjectiveThere is evidence that metabolic disorder, dysfunction and abnormal apoptosis of immune cells are closely related to immunosuppression in sepsis. Single monitoring of exhaustion receptors does not reflect well the immune status of septic patients; therefore, we monitored immune status in relation to metabolism, function and apoptosis of immune cells to find good prognostic indicators for sepsis.DesignA single-center prospective observational study.SettingTeaching hospital including an academic tertiary care center.Patients81 patients with sepsis and 22 without sepsis admitted to the ICU.InterventionsPatients were divided according to Sequential Organ Failure Assessment (SOFA) score: mild sepsis 2–5 points and severe sepsis ≥6 points. SOFA score was recalculated daily. If it changed by ≥2 points within 2 days, T-cell metabolism, function and apoptotic makers [mammalian target of rapamycin (mTOR), T-bet, interferon (IFN)-γ, granzyme B, and programmed cell death (PD)-1] were continuously monitored on days 1, 3 and 5 after admission.Measurements and Main ResultsThe overall status of immune cells was compared among patients with different severity of sepsis. Patients with severe sepsis, compared with mild and no sepsis, had lower lymphocyte counts, higher expression of receptors associated with cell metabolism, activation and apoptosis, and lower expression of functional receptors. Multivariate regression analysis revealed that frequency of CD4+ T cells expressing mTOR, IFN-γ and PD-1 at admission was an independent predictor of 28-day mortality. Receiver operating characteristic curve analysis indicated that frequency of CD4+ T cells expressing mTOR, IFN-γ and PD-1 predicted 28-day mortality, with cutoffs of 30.57%, 12.81% and 22.46%, respectively. The expression of related receptors on CD8+ T cells showed similar trend to that on CD4+ T cells, but no significant difference was found.ConclusionsAbnormally increased expression of metabolic and apoptotic receptors on CD4+ T cells and decreased expression of functional factors are associated with poor prognosis in ICU patients with sepsis. Poor prognosis can be identified by early detection of expression of mammalian target of rapamycin (mTOR), IFN-γ and PD-1 on CD4+ T cells.</p

    Layer-by-Layer Assembly and UV Photoreduction of Graphene–Polyoxometalate Composite Films for Electronics

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    Graphene oxide (GO) nanosheets and polyoxometalate clusters, H3PW12O40 (PW), were co-assembled into multilayer films via electrostatic layer-by-layer assembly. Under UV irradiation, a photoreduction reaction took place in the films which converted GO to reduced GO (rGO) due to the photocatalytic activity of PW clusters. By this means, uniform and large-area composite films based on rGO were fabricated with precisely controlled thickness on various substrates such as quartz, silicon, and plastic supports. We further fabricated field effect transistors based on the composite films, which exhibited typical ambipolar features and good transport properties for both holes and electrons. The on/off ratios and the charge carrier mobilities of the transistors depend on the number of deposited layers and can be controlled easily. Furthermore, we used photomasks to produce conductive patterns of rGO domains on the films, which served as efficient microelectrodes for photodetector devices

    Supramolecular Anchoring of Polyoxometalate Amphiphiles into Nafion Nanophases for Enhanced Proton Conduction

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    Advanced proton exchange membranes (PEMs) are highly desirable in emerging sustainable energy technology. However, the further improvement of commercial perfluorosulfonic acid PEMs represented by Nafion is hindered by the lack of precise modification strategy due to their chemical inertness and low compatibility. Here, we report the robust assembly of polyethylene glycol grafted polyoxometalate amphiphile (GSiW11) into the ionic nanophases of Nafion, which largely enhances the comprehensive performance of Nafion. GSiW11 can coassemble with Nafion through multiple supramolecular interactions and realize a stable immobilization. The incorporation of GSiW11 can increase the whole proton content in the system and induce the hydrated ionic nanophase to form a wide channel for proton transport; meanwhile, GSiW11 can reinforce the Nafion ionic nanophase by noncovalent cross-linking. Based on these synergistic effects, the hybrid PEMs show multiple enhancements in proton conductivity, tensile strength, and fuel cell power density, which are all superior to the pristine Nafion. This work demonstrates the intriguing advantage of molecular nanoclusters as supramolecular enhancers to develop high-performance electrolyte materials

    Noncovalent Functionalization of Graphene Nanosheets with Cluster-Cored Star Polymers and Their Reinforced Polymer Coating

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    A noncovalent and phase-transfer-assisted method is developed for the fabrication of polymer-functionalized graphene, in which a series of cluster-cored star polymers (CSPs) containing a polyoxometalate core and polystyrene (PS) arms are used as modifiers. Through the electron transfer interaction between polyoxometalate and graphene, the CSPs can strongly adsorb on graphene nanosheets and transfer them from aqueous media to organic solvents like chloroform, forming individually dispersed graphene. Moreover, the CSP-functionalized graphene is well compatible with additional polymer matrices and can serve as a reinforcing nanofiller for polymer composites. A 0.2 wt% loading of them in PS coating achieves a 98.9% high enhancement in Young’s modulus
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