Transition metal sulfide, especially NiCo2S4, is of great interest as the promising battery-type electrode material for asymmetric supercapacitor (ASC). However, such material has its own ...disadvantages of energy waste of preparation and poor electrical conductivity. In this work, we adopted a green and environmentally friendly room-temperature sulfurization method to successfully prepare the electrode material (ACF/NCS-HL) with activated carbon fiber (ACF) as the core and honeycomb-like NiCo2S4 as the shell (NCS-HL). This material has porous structure with heterogeneous redox electron pairs and shows excellent electrochemical performance. The optimized ACF/NCS-HL exhibits remarkable specific capacitance of 1682 F g−1 at 1 A g−1 in 2 M KOH aqueous electrolyte in the three-electrode system. The asymmetric supercapacitor device with ACF/NCS-HL as positive electrode and ACF as negative electrode shows the high energy density of 49.38 W h kg−1 at the power density of 800 W kg−1 and the preeminent cycle stability up to 82.88% after 5000 cycles, indicating its promising potential application in the future as high-performance supercapacitors.
An integral finite element model of steel circular hollow section and welded hollow spherical joints is established to consider the restraint of welded hollow spherical joints on steel circular ...hollow section in this paper. The buckling modes are used as the initial geometrical imperfection forms of the steel circular hollow section. Based on the statistics method, a method for calculating the buckling capacity design value of the steel circular hollow section with uniform reliability considering the restraint of welded hollow spherical joints is established, and the formula for calculating error of this value at certain confidence is deduced. The relationships between the buckling capacity design value of steel circular hollow section and the structural parameters of the member and joint are determined quantitatively by linear regression method. A practical formula for the buckling capacity design value of steel circular hollow section considering the restraint of welded hollow spherical joints is derived. Compared to the results calculated by the design code indicates that if the difference of restraint effect which is caused by different welded hollow spherical joint is ignored, the buckling capacity value of steel circular hollow section calculated based on the unified effective length coefficient may be bigger or smaller than that of the actual case. Therefore, refined consideration should be placed on the different restraint of welded hollow spherical joints of different sizes on steel circular hollow section, and the restraint of the end joints should be accurately considered when determining the buckling capacity of steel circular hollow sections.
In this work, hexagonal boron nitride powders (h-BN) and heat-treatment (HT) were used to tailor microstructures and tribological properties for Carbon/Carbon composites. The microstructures and ...tribological behaviors of virgin Carbon/Carbon, h-BN modified Carbon/Carbon, Carbon/Carbon after HT, and Carbon/Carbon modified by h-BN with HT were investigated. Results indicate that h-BN powdered addition as matrix leads to PyC matrix with higher texture degree, graphitization and micro-hardness, compared to virgin Carbon/Carbon composites. Moreover, compared to virgin Carbon/Carbon, the coefficient of friction (COF) of h-BN modified Carbon/Carbon composites are increased to 0.29 while wear rates (WR) are decreased to 1.65 μm·side−1·circle−1. However, the Carbon/Carbon composites modified by h-BN and HT presented quite lower COF and WR, in comparison to virgin Carbon/Carbon and Carbon/Carbon after HT. In summary, flexibly tailored COF and WR could be achieved via BN powdered addition and/or HT.
Construction of Z-scheme heterojunction catalysts with high-speed charge transfer channels for efficient photocatalytic hydrogen production from water splitting is still a challenge. In this work, a ...lattice-defect-induced atom migration strategy is proposed to construct an intimate interface. The oxygen vacancies of cubic CeO
obtained from a Cu
O template are used to induce lattice oxygen migration and form SO bonds with CdS to form a close contact heterojunction with a hollow cube. The hydrogen production efficiency reaches ∼12.6 mmol·g
·h
and maintains a high value over 25 h. A series of photocatalytic tests combined with density functional theory (DFT) calculations show that the close contact heterostructure not only promotes the separation/transfer of photogenerated electron-hole pairs but also regulates the intrinsic catalytic activity of the surface. A large number of oxygen vacancies and SO bonds at the interface participate in charge transfer, which accelerates the migration of photogenerated carriers. The hollow structure improves the ability to capture visible light. Therefore, the synthesis strategy proposed in this work, as well as the in-depth discussion of the interface chemical structure and charge transfer mechanism, provides new theoretical support for the further development of photolytic hydrogen evolution catalysts.
To increase our knowledge of PM
2.5
concentrations near the surface in a forest park in Beijing, an observational study measured the concentration and composition of PM
2.5
in Beijing Olympic Forest ...Park from 2014 to 2015. This study analyzed the meteorological factors and removal efficiency at 1.5 m above the ground (human breathing height) over the day in the forest. The results showed that the average concentrations of PM
2.5
near the surface peaked at 07:00–09:30 and reached their lowest at 12:00–15:00. Besides, the results showed that the annual concentration of PM
2.5
in the forest was highest during winter, followed by spring and fall, and was lowest during summer. The main chemical components of PM
2.5
near the surface in the forest were SO
4
2−
and NO
3
−
, which accounted for 68.72% of all water-soluble ions that we observed. The concentration of PM
2.5
in the forest had a significant positive correlation with relative humidity and a significant negative correlation with temperature. The removal efficiency near the surface showed no significant variation through the day or year. In the forest, the highest removal efficiency occurred between 07:00 and 09:30 in summer, while the lowest occurred between 09:30 and 12:00 in winter.
Bioorthogonal reactions have been widely used in biomedical field.
18
F-TCO/Tetrazine ligation is the most reactive radiolabelled inverse electron demand Diels-Alder reactions, but its application ...had been limited due to modest contrast ratios of the resulting conjugates. Here we describe the use of hydrophilic tetrazines to improve tumor to background contrast of neurotensin receptor targeted PET agents. PET agents were constructed using a rapid Diels-Alder reaction of the radiolabeled
trans-
cyclooctene (
18
F-sTCO) with neurotensin (NT) conjugates of a 3,6-diaryltetrazine, 3-methyl-6-aryltetrazine, and a derivative of 3,6-di-(2-hydroxyethyl)tetrazine. Although cell binding assay demonstrated all agents have comparable binding affinity, the conjugate derived from 3,6-di-(2-hydroxyethyl)tetrazine demonstrated the highest tumor to muscle contrast, followed by conjugates of the 3-methyl-6-aryltetrazine and 3,6-diaryltetrazine.
Hydrophilic tetrazines lead to improved tumor to background contrast in PET probe construction.
Chromophores that absorb in the tissue-penetrant far-red/near-infrared window have long served as photocatalysts to generate singlet oxygen for photodynamic therapy. However, the cytotoxicity and ...side-reactions associated with singlet oxygen sensitization have posed a problem for using long-wavelength photocatalysis to initiate other types of chemical reactions in biological environments. Herein, Si-Rhodamines (SiR) are described as photocatalysts for inducing rapid bioorthogonal chemistry using 660 nm light through the oxidation of a dihydrotetrazine to a tetrazine in the presence of
trans
-cyclooctene dienophiles. SiRs have been commonly used as fluorophores for bioimaging, but have not been applied to catalyze chemical reactions. A series of SiR derivatives were evaluated, and the Janelia Fluor-SiR dyes were found to be especially effective in catalyzing photooxidation (typically 3%). A dihydrotetrazine/tetrazine pair is described that displays high stability in both oxidation states. A protein that was site-selectively modified by
trans
-cyclooctene was quantitively conjugated upon exposure to 660 nm light and a dihydrotetrazine. By contrast, a previously described methylene blue catalyst was found to rapidly degrade the protein. SiR-red light photocatalysis was used to crosslink hyaluronic acid derivatives functionalized by dihydrotetrazine and
trans
-cyclooctenes, enabling 3D culture of human prostate cancer cells. Photoinducible hydrogel formation could also be carried out in live mice through subcutaneous injection of a Cy7-labeled hydrogel precursor solution, followed by brief irradiation to produce a stable hydrogel. This cytocompatible method for using red light photocatalysis to activate bioorthogonal chemistry is anticipated to find broad applications where spatiotemporal control is needed in biological environments.
The overall survival rate of gliomas has not significantly improved despite new effective treatments, mainly due to tumor heterogeneity and drug delivery. Here, we perform an integrated ...clinic-genomic analysis of 1, 477 glioma patients from a Chinese cohort and a TCGA cohort and propose a potential prognostic model for gliomas. We identify that SBS11 and SBS23 mutational signatures are associated with glioma recurrence and indicate worse prognosis only in low-grade type of gliomas and IDH-Mut subtype. We also identify 42 genomic features associated with distinct clinical outcome and successfully used ten of these to develop a prognostic risk model of gliomas. The high-risk glioma patients with shortened survival were characterized by high level of frequent copy number alterations including PTEN, CDKN2A/B deletion, EGFR amplification, less IDH1 or CIC gene mutations, high infiltration levels of immunosuppressive cells and activation of G2M checkpoint and Oxidative phosphorylation oncogenic pathway.
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•Systematical evaluation of prognostic value of genomic features in over 1400 gliomas•SBS11 mutational signature is associated with glioma recurrence•SBS11 mutational signature predicts worse prognosis in low-grade gliomas•Prediction of high-risk gliomas with shortened survival
Genetics; Genomics; Cancer
The past decade has seen a remarkable growth in the number of bioconjugation techniques in chemistry, biology, material science, and biomedical fields. A core design element in bioconjugation ...technology is a chemical reaction that can form a covalent bond between the protein of interest and the labeling reagent. Achieving chemoselective protein bioconjugation in aqueous media is challenging, especially for generally less reactive amino acid residues, such as tryptophan. We present here the development of tryptophan-selective bioconjugation methods through ultrafast Lewis acid-catalyzed reactions in hexafluoroisopropanol (HFIP). Structure–reactivity relationship studies have revealed a combination of thiophene and ethanol moieties to give a suitable labeling reagent for this bioconjugation process, which enables modification of peptides and proteins in an extremely rapid reaction unencumbered by noticeable side reactions. The capability of the labeling method also facilitated radiofluorination application as well as antibody functionalization. Enhancement of an α-helix by HFIP leads to its compatibility with a certain protein, and this report also demonstrates a further stabilization strategy achieved by the addition of an ionic liquid to the HFIP medium. The nonaqueous bioconjugation approaches allow access to numerous chemical reactions that are unavailable in traditional aqueous processes and will further advance the chemistry of proteins.
Pollution of aquatic environment by difenoconazole (DFZ) significantly affects survival and safety of freshwater aquaculture. Due to its anti-inflammatory and antioxidant properties, plant-derived ...quercetin (QUE) is often used as a dietary supplement. The main purpose of this study was to explore the protective effect of QUE on heart damage caused by exposure to pesticide DFZ and the potential mechanisms of these effects. This study found that QUE could effectively reduce the myocardial enzyme spectrum index of carp after exposure to DFZ, increase the levels of total antioxidant capacity (T-AOC), glutathione (GSH), and catalase (CAT), inhibit the content of malondialdehyde (MDA), and increase the transcription levels of superoxide dismutase (sod), glutathione peroxidase (gsh-px), and cat. By reducing the expression of keap1, QUE increased the transcription levels of nrf2 and nqo-1, reduced the production of reactive oxygen species (ROS) in the heart after exposure to DFZ, and restored the redox homeostasis of the heart. QUE upregulated the expression of anti-inflammatory cytokines il-10 and tgf-β1 levels, downregulated the transcription levels of pro-inflammatory factor inos, il-1β, il-6 and tnf-α, and alleviated the in vivo redox imbalance caused by exposure to DFZ, leading to myocardial interstitial inflammatory cell infiltration. The results showed that QUE inhibited the apoptosis after exposure to DFZ by affecting the expression of apoptotic factors in the mitochondrial apoptotic pathway. In summary, QUE can effectively decrease myocardial injury caused by exposure to DFZ in aquatic environment.
•The pesticide difenoconazole can cause carp cardiac pathological damage.•Quercetin can reduce cardiac tissue damage induced by difenoconazole.•Quercetin may reduce oxidative stress, inflammation and apoptosis.
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