The brittleness of epoxy resin (EP) and the smooth, inert surface of carbon fiber (CF) affects their interfacial interaction, making the composite exhibit poor interlaminar shear properties that ...significantly limit its practical application. In this paper, a 4,4‐diphenylmethane diisocyanate (MDI) layer was uniformly coated on short‐cut carbon fiber (SCF) by chemical bonding and physical cladding. The reaction of the isocyanate group of MDI with the active hydrogen in the epoxy system was used to form a strong chemical bond between EP and SCF to enhance the interfacial interaction. Moreover, the introduced SCF as filler can play a better connecting and anchoring role in the CF/EP composite, enabling better stress transfer and enhancing the integrity inside the composite. The coating of MDI on the surface of SCF and the efficient synergistic effect that it brings were successfully demonstrated by Fourier‐transform infrared, thermogravimetric analyzer, dynamic mechanics analyzer, scanning electron microscopy, and interlaminar shear strength characterization. Compared with the untreated SCF reinforced CF/EP composite, MDI@SCF enhanced the interlaminar performance of the material by 10.06%. When the concentration of MDI treatment solution and SCF content was adjusted to the optimal value, the interlayer performance of the material increased by 17.01% compared to the pure CF/EP composite.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract Narrow-line Seyfert 1 galaxies (NLS1s), a subclass of active galactic nuclei (AGNs) in an early stage of the accretion process, are also found to host relativistic jets. However, currently ...known jetted NLS1s are rare. The majority of NLS1s are undetected at the radio band. The radio detection rate of NLS1s increases with the LOFAR Two-metre Sky Survey (LoTSS), which provides a good opportunity for finding more jetted NLS1s. The better sensitivity raises the question whether the radio emission of NLS1s with a low radio luminosity originates from the jet activity. In order to clarify the origin of the radio emission for NLS1s and search for more jetted NLS1s, we explore the mid-infrared properties of LoTSS-detected NLS1s by comparing them with known jetted AGNs and star-forming galaxies (SFGs), which are located above and on the well-studied radio/far-infrared correlation, respectively. The majority of NLS1s show mid-infrared (MIR) excess compared with SFGs. Their radio emission shows a significant correlation with the MIR emission. In the MIR color–color diagram, NLS1s overlap flat spectrum radio quasars, but they are well separated from SFGs and optically selected radio galaxies. The flux ratio of the radio and MIR emission of these NLS1s is also similar to that of a radio-quiet quasar with a weak jet. These results imply substantial contributions from the AGN activities for both the radio and MIR emission of NLS1s. A small fraction of NLS1s with relatively higher radio luminosities are located in a similar region as blazars in the radio-MIR diagram, which suggests that the radio emission of these NLS1s is dominated by the jet. We obtain a sample of jetted NLS1 candidates through their radio excess in the radio-MIR diagram.
Lead halide perovskite nanocrystals (NCs) have demonstrated great potential as appealing candidates for advanced optoelectronic applications. However, the toxicity of lead and the intrinsic ...instability toward moisture hinder their mass production and commercialization. Herein, to solve such thorny problems, novel lead‐free Cs2AgBiBr6 double perovskite NCs fabricated via a simple hot‐injection method are reported, which exhibit impressive stability in moisture, light, and temperature. Such materials are then applied into photocatalytic CO2 reduction, achieving a total electron consumption of 105 µmol g−1 under AM 1.5G illumination for 6 h. This study offers a reliable avenue for Cs2AgBiBr6 perovskite nanocrystals preparation, which holds a great potential in the further photochemical applications.
Stable lead‐free Cs2AgBiBr6 double perovskite nanocrystals with a cubic shape and an average size of 9.5 nm are successfully synthesized via the hot‐injection route, and are employed as photocatalysts to convert CO2 into solar fuels (CO and CH4). This work offers a reliable avenue for Cs2AgBiBr6 perovskite nanocrystals preparation, which holds a great potential in the further photochemical applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Hydrogen has been hailed as a clean and sustainable alternative to finite fossil fuels in many energy systems. Water splitting is an important method for hydrogen production in high purity and large ...quantities. To accelerate the hydrogen evolution reaction (HER) rate, it is highly necessary to develop high efficiency catalysts and to select a proper electrolyte. Herein, the performances of non‐noble metal‐based carbon composites under various pH values (acid, alkaline and neutral media) for HER in terms of catalyst synthesis, structure and molecular design are systematically discussed. A detailed analysis of the structure‐activity‐pH correlations in the HER process gives an insight on the origin of the pH‐dependence for HER, and provide guidance for future HER mechanism studies on non‐noble metal‐based carbon composites. Furthermore, this Review gives a fresh impetus to rational design of high‐performance noble‐metal‐free composites catalysts and guide researchers to employ the established electrocatalysts in proper water electrolysis technologies.
Non‐noble‐metal‐based carbon composites for electrochemical hydrogen production are summarized and the relationships between electrocatalyst structure–activity–pH are systematically discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Halide perovskite quantum dots (QDs), primarily regarded as optoelectronic materials for LED and photovoltaic devices, have not been applied for photochemical conversion (e.g., water splitting or CO2 ...reduction) applications because of their insufficient stability in the presence of moisture or polar solvents. Herein, we report the use of CsPbBr3 QDs as novel photocatalysts to convert CO2 into solar fuels in nonaqueous media. Under AM 1.5G simulated illumination, the CsPbBr3 QDs steadily generated and injected electrons into CO2, catalyzing CO2 reduction at a rate of 23.7 μmol/g h with a selectivity over 99.3%. Additionally, through the construction of a CsPbBr3 QD/graphene oxide (CsPbBr3 QD/GO) composite, the rate of electron consumption increased 25.5% because of improved electron extraction and transport. This study is anticipated to provide new opportunities to utilize halide perovskite QD materials in photocatalytic applications.
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IJS, KILJ, NUK, PNG, UL, UM
In metabolism, available free energy is limited and must be divided across pathway steps to maintain a negative ΔG throughout. For each reaction, ΔG is log proportional both to a concentration ratio ...(reaction quotient to equilibrium constant) and to a flux ratio (backward to forward flux). Here we use isotope labeling to measure absolute metabolite concentrations and fluxes in Escherichia coli, yeast and a mammalian cell line. We then integrate this information to obtain a unified set of concentrations and ΔG for each organism. In glycolysis, we find that free energy is partitioned so as to mitigate unproductive backward fluxes associated with ΔG near zero. Across metabolism, we observe that absolute metabolite concentrations and ΔG are substantially conserved and that most substrate (but not inhibitor) concentrations exceed the associated enzyme binding site dissociation constant (Km or Ki). The observed conservation of metabolite concentrations is consistent with an evolutionary drive to utilize enzymes efficiently given thermodynamic and osmotic constraints.
Photoresponsive supramolecular polymers are well‐organized assemblies based on highly oriented and reversible noncovalent interactions containing photosensitive molecules as (co‐)monomers. They have ...attracted increasing interest in smart materials and dynamic systems with precisely controllable functions, such as light‐driven soft actuators, photoresponsive fluorescent anticounterfeiting and light‐triggered electronic devices. The present review discusses light‐activated molecules used in photoresponsive supramolecular polymers with their main photo‐induced changes, e.g., geometry, dipole moment, and chirality. Based on these distinct changes, supramolecular polymers formed by light‐activated molecules exhibit photoresponsive disassembly and reassembly. As a consequence, photo‐induced supramolecular polymerization, “depolymerization,” and regulation of the lengths and topologies are observed. Moreover, the light‐controlled functions of supramolecular polymers, such as actuation, emission, and chirality transfer along length scales, are highlighted. Furthermore, a perspective on challenges and future opportunities is presented. Besides the challenge of moving from harmful UV light to visible/near IR light avoiding fatigue, and enabling biomedical applications, future opportunities include light‐controlled supramolecular actuators with helical motion, light‐modulated information transmission, optically recyclable materials, and multi‐stimuli‐responsive supramolecular systems.
Control over supramolecular interactions is an important part of the toolbox for developing functional materials. The design of supramolecular polymers with light‐triggered molecules allows remote control of supramolecular polymers and materials with high spatiotemporal precision. Here, a perspective review of various approaches and major advances toward photoresponsive supramolecular polymers with controlled functions is presented.
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Nanostructural modification and chemical composition tuning are paramount to developing effective non-noble hydrogen evolution reaction (HER) catalysts for water splitting. Herein, we report a novel ...excellent porous molybdenum tungsten phosphide (Mo-W-P) hybrid nanosheet catalyst for hydrogen evolution, which is synthesized via in situ phosphidation of molybdenum tungsten oxide (Mo-W-O) hybrid nanowires grown on carbon cloth. The three-dimensional (3D) hierarchical hybrid electrocatalyst exhibits impressively high electrocatalytic activity with a low overpotential of 138 mV required to achieve a high current density of 100 mA cm-2 and a small Tafel slope of 52 mV dec-1 in 0.5 M H2SO4, which are significantly higher than those of single MoP nanosheets and WP2 nanorods. Such an outstanding performance of the Mo-W-P hybrid electrocatalyst is attributed to the 3D conductive scaffolds, porous nanosheet structure, and strong synergistic effect of W and Mo atoms in Mo-W-P, making it a very promising catalyst for hydrogen production. Our findings demonstrate that careful control over the morphology and composition of the electrocatalyst can achieve highly efficient hybrid electrocatalysts.
Halide perovskite single-crystals have recently been widely highlighted to possess high light harvesting capability and superior charge transport behaviour, which further enable their attractive ...performance in photovoltaics. However, their application in photoelectrochemical cells has not yet been reported. Here, a methylammonium lead bromide MAPbBr
single-crystal thin film is reported as a photoanode with potential application in photoelectrochemical organic synthesis, 2,5-dimethoxy-2,5-dihydrofuran. Depositing an ultrathin Al
O
layer is found to effectively passivate perovskite surface defects. Thus, the nearly 5-fold increase in photoelectrochemical performance with the saturated current being increased from 1.2 to 5.5 mA cm
is mainly attributed to suppressed trap-assisted recombination for MAPbBr
single-crystal thin film/Al
O
. In addition, Ti
-species-rich titanium deposition has been introduced not only as a protective film but also as a catalytic layer to further advance performance and stability. As an encouraging result, the photoelectrochemical performance and stability of MAPbBr
single-crystal thin film/Al
O
/Ti-based photoanode have been significantly improved for 6 h continuous dimethoxydihydrofuran evolution test with a high Faraday efficiency of 93%.
Objective
Previous observational studies demonstrated that a subset of patients with systemic lupus erythematosus (SLE) have markedly short telomere length in leukocytes. This study was undertaken to ...test whether leukocyte telomere length is causally associated with risk of SLE.
Methods
A 2‐sample Mendelian randomization (MR) analysis was conducted to estimate causality of telomere length on SLE in European populations. A replication 2‐sample MR study using Asian genetic data was also conducted. A reverse MR analysis was then performed to test the effects of SLE on telomere length. The autoantibodies targeting telomere‐associated protein (telomeric repeat–binding factor 1 TERF1 autoantibodies) were detected in patients with SLE, healthy controls, and patients with rheumatoid arthritis.
Results
The results of the inverse variance–weighted method (odds ratio OR 2.96 95% confidence interval (95% CI) 1.58–5.55, P < 0.001) showed strong evidence for a causal relationship between longer telomere length and risk of SLE in people with European ancestry. The outcomes of MR‐Egger regression analysis (OR 29.46 95% CI 3.02–287.60, P = 0.033) and MR pleiotropy residual sum and outlier analysis (OR 3.62 95% CI 2.03–6.46, P = 0.002) also showed that longer telomere length was significantly associated with increased risk of SLE in a European population. Sensitivity analyses using different methods and summary data sets showed that the results were still broadly consistent. A replication MR study using Asian genetic data yielded similar findings. However, the reverse MR analysis showed that genetically predicted SLE was not causally associated with telomere length. In addition, we found that TERF1 autoantibodies were present in 2 of 40 SLE patients (5.0%).
Conclusion
In contrast with previous observational studies, MR analyses show that longer telomere length is significantly associated with increased risk of SLE.
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