Hastingsnavarro4773

Besides a superhydrophobic feature, the poly(VS-co-HEA)-coated PU foam can self-extinguish a flame, exhibiting a desired V-0 rating during vertical burning and low heat and smoke release due to its high charring capability, which is superior to its previous counterparts. Moreover, the foam thermal insulation is well-preserved and agrees well with theoretical calculations. This work offers a facile biomimetic strategy for creating advanced adhesive fire-retardant polymeric coatings for many flammable substrates.Protocols to create metal-organic framework (MOF)/polymer composites for separation, chemical capture, and catalytic applications currently rely on relatively slow solution-based processing to form single MOF composites. Here, we report a rapid, high-yield sorption-vapor method for direct simultaneous growth of single and multiple MOF materials onto untreated flexible and stretchable polymer fibers and films. The synthesis utilizes favorable reactant absorption into polymers coupled with rapid vapor-driven MOF crystallization to form high surface area (>250 m2/gcomposite) composites, including UiO-66-NH2, HKUST-1, and MOF-525 on spandex, nylon, and other fabrics. The resulting composites are robust and maintain their functionality even after stretching. Stretchable MOF fabrics enable rapid solid-state hydrolysis of the highly toxic chemical warfare agent soman and paraoxon-methyl simulant. We show that this approach can readily be scaled by solution spray-coating of MOF precursors and to large area substrates.Fatty acid esters of hydroxy fatty acids (FAHFAs) are a new class of endogenous lipids with promising physiological functions in mammals. We previously introduced a new type of lipids to this family called short-chain fatty acid esters of hydroxy fatty acids (SFAHFAs), branching specific to the C2 carbon of a long-chain fatty acid (≥C20). In this study, we discovered a homologous series of SFAHFAs comprising C16-C26 hydroxy fatty acids esterified with short-chain fatty acids (C2-C5) in mouse colon contents. The detected SFAHFAs were characterized by high-resolution mass spectrometry with MSn analysis. The double-bond position of monounsaturated SFAHFAs was determined by the epoxidation reaction of samples with m-chloroperoxybenzoic acid and their MSn analysis. Further, the measurement of SFAHFA concentration in the colon contents of mice infected with influenza A/Puerto Rico/8/34 (H1N1; PR8) virus revealed a significant increase in their levels compared to native control. A strong correlation was observed between hydroxy fatty acid and SFAHFAs. Detection, characterization, and profiling of these new SFAHFA levels in relation with pandemic H1N1; PR8 influenza virus will contribute to the in-depth study of their function and metabolism.Efficient organic light-emitting diodes (OLEDs) consist of an emissive layer comprising a blend of a light-emitting and host material in contact with one or more charge transporting layers. The distribution of the active material in the guest-host emissive layer blend and the changes that may occur upon thermal annealing are two important factors in determining the stability and efficiency of OLEDs. We have combined neutron reflectometry and photoluminescence measurements to investigate the structures of films comprising an emissive layer containing a phosphorescent poly(dendrimer) material blended with 4,4'-N,N'-di(carbazolyl)biphenyl. This combination has been shown to give rise to highly efficient OLEDs. Here, we show that the emissive poly(dendrimer) material was not uniformly distributed in the host, but formed a concentration gradient within the emissive layer. Upon heating, the adjacent electron transport layer was found to intermix with the emissive layer, accompanied by changes in the material distribution in the emissive layer. The intermixing of the materials led to a decrease in the photoluminescence from the poly(dendrimer) within the film. The decrease in the photoluminescence was ascribed to an increase in interchromophore interactions that could arise from a conformational change of the poly(dendrimer) or phase separation leading to aggregation. The results indicate that, while uniform mixing of the guest and host is not essential for efficiency, the thermal stabilities of both host and charge transport materials are important for device durability.Three-dimensional aromaticity arising from the close stacking of two antiaromatic π-conjugated macrocycles has recently received considerable attention. Here, a cyclophane consisting of two antiaromatic Ni(II) norcorrole units tethered with two flexible alkyl chains was synthesized. The norcorrole cyclophane showed crystal polymorphism providing three different solid-state structures. click here Surprisingly, one of them adopted an aligned face-to-face stacking arrangement with negligible displacement along the slipping axis. Although the exchange repulsion between two π-clouds should be maximized in this orientation, the π-π distance is remarkably close (3.258 Å). Three-dimensional aromaticity in this conformation has been supported experimentally and theoretically as evidenced by small bond length alternations as well as the presence of a diatropic ring current. An analogous cyclophane with two aromatic Ni(II) porphyrin units was prepared for comparison. The porphyrin cyclophane exhibited a slipped-stacking conformation with a larger displacement (2.9 Å) and a larger interplanar distance (3.402 Å) without noticeable change of the aromaticity of each porphyrin unit. In solution, the norcorrole cyclophane forms a twist stacking arrangement with effective interplanar orbital overlap and exists in an equilibrium between stacked and nonstacked structures. Thermodynamic parameters of the stacking process were estimated, revealing an inherently large attractive interaction operating between two norcorrole units, which has been further supported by energy decomposition analysis.Tissue-mimetic silk hydrogels are being explored for diverse healthcare applications, including stem cell delivery. However, the impact of stress relaxation of silk hydrogels on human mesenchymal stem cell (MSC) biology is poorly defined. The aim of this study was to fabricate silk hydrogels with tuned mechanical properties that allowed the regulation of MSC biology in two dimensions. The silk content and stiffness of both elastic and viscoelastic silk hydrogels were kept constant to permit direct comparisons. Gene expression of IL-1β, IL-6, LIF, BMP-6, BMP-7, and protein tyrosine phosphatase receptor type C were substantially higher in MSCs cultured on elastic hydrogels than those on viscoelastic hydrogels, whereas this pattern was reversed for insulin, HNF-1A, and SOX-2. Protein expression was also mechanosensitive and the elastic cultures showed strong activation of IL-1β signaling in response to hydrogel mechanics. An elastic substrate also induced higher consumption of glucose and aspartate, coupled with a higher secretion of lactate, than was observed in MSCs grown on viscoelastic substrate.