Kinetics and Mechanism of Hydrothermal Decomposition of Lignin Model Compounds

The kinetics and underlying mechanisms of the hydrothermal decomposition of the lignin model compounds anisole, diphenyl ether and phenethyl phenyl ether were studied. Whereas diphenyl ether was stable at hydrothermal conditions, anisole and phenethyl phenyl ether underwent hydrothermal decomposition between 260 and 290 °C. Experiments involving different initial reactant concentrations and different batch holding times revealed that hydrolysis of both anisole and phenethyl phenyl ether followed first-order kinetics. Experiments at different temperatures showed that the first-order rate constants displayed Arrhenius behavior, with activation energies of 149.8 ± 16.4 and 143.2 ± 21.0 kJ·mol^–1 for anisole and phenethyl phenyl ether, respectively. A reaction mechanism is proposed for anisole, and reaction pathways for the decomposition of phenethyl phenyl ether are proposed based on the distribution of the products generated by hydrolysis. The reactivity of ether hydrothermal decomposition is discussed by reviewing the published conversion data of other ethers

Anticorrosion Improvement of Waterborne Epoxy-Acrylate Coatings by Constructing <i>g</i>‑C₃N₄ Functionalized by Polyaniline-Coated Zinc Phosphate

In response to the poor anticorrosion properties of waterborne coatings, g-C3N4 coated with zinc phosphate and polyaniline (PANI) was synthesized by in situ polymerization. Added to water-based epoxy-acrylate (WEP) emulsions, this new composite is used as an anticorrosive agent to protect metal substrates. The PANI film on the surface of g-C3N4 (denoted as CA) guarantees excellent g-C3N4 dispersion owing to the hydrophilic groups. The addition of zinc phosphate was to improve the corrosion protection ability of the composite (denoted as CAZP). The structure and chemical composition of the CAZP composite were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Transmission electron microscopy was used to monitor the morphological changes of the composites and scanning electron microscopy to characterize the topography of different coatings. By applying these analyses, the successful formation of CAZP was confirmed. The anticorrosion performance of g-C3N4, CA, and CAZP coatings on Q235 carbon steel in 3.5 wt % NaCl solution was evaluated by electrochemical impedance spectroscopy and dynamic potential polarization curves. The results show that even after prolonged immersion (60 days) in the NaCl solution, the |Z0.01Hz| of CAZP/WEP was still as high as 1.69 × 109 Ω·cm2. The corrosion rate was reduced to 9.590 × 10–6 mpy, 3 orders of magnitude lower than that of the blank coating. This indicates that CAZP/WEP has excellent corrosion protection properties

Copper-Catalyzed Direct Asymmetric Vinylogous Mannich Reaction between β,γ-Alkynyl-α-ketimino Esters and β,γ-Unsaturated <i>N</i>‑Acylpyrazoles

We report a Cu(I)–Ph-BPE-catalyzed asymmetric vinylogous Mannich reaction of β,γ-alkynyl-α-ketimino esters with β,γ-unsaturated N-acylpyrazoles. In this process, the Cu(I)–Ph-BPE catalyst activates the β,γ-alkynyl-α-ketimino ester through N,O-coordination, enabling the subsequent nucleophilic addition of a dienolate generated from the β,γ-unsaturated N-acylpyrazole via α-position deprotonation with a catalytic amount of tertiary amine. The reactions gave useful products with very high enantioselectivities. A broad range of substrates with various substituents are tolerated in this reaction. The versatility of this method was demonstrated by a gram-scale reaction, and subsequent elaboration of the Mannich adducts was also provided

Additional file 1 of Unenhanced CT-based predictive model to identify small bowel necrosis in patients with mechanical small bowel obstruction

Supplementary Material

Enantioselective Intermolecular Formal [3 + 3] Cycloaddition of 2,3-Disubstituted Indoles with Acrolein

An expedient enantioselective synthesis of highly substituted hydrocarbazoles has been realized by an organocatalyzed formal [3 + 3] cycloaddition between acrolein and 2,3-disubstituted indoles. Tricyclic hydrocarbazoles were obtained from a broad range of 2,3-disubstituted indoles and acrolein in good to excellent yields and excellent enantioselectivites

Reduction of Benzolactams to Isoindoles via an Alkoxide-Catalyzed Hydrosilylation

An alkoxide-catalyzed reduction of benzolactams to isoindoles with silanes was realized. With <i>t</i>-BuOK as the catalyst and Ph₂SiH₂ as the reductant, a series of benzolactams containing different functional groups were reduced to the corresponding isoindoles, which could be captured by <i>N</i>-phenyl maleimide to form Diels–Alder products in moderate to good yields. Deuterium labeling studies and the hydrosilylation of benzolactam in DMF indicated that the deprotonation of benzolactams took place at C3 potion during the reduction

Image_1_MptpB Promotes Mycobacteria Survival by Inhibiting the Expression of Inflammatory Mediators and Cell Apoptosis in Macrophages.PDF

<p>Tuberculosis is a severe contagious disease caused by Mycobacterium tuberculosis (Mtb). To develop new vaccines and medicine against TB, there is an urgent need to provide insights into the mechanisms by which Mtb induces tuberculosis. In this study, we found that secreted Mtb virulence factor MptpB significantly enhanced the survival of H37Rv in macrophages. MptpB suppressed the production of iNOS, the expression of inflammatory factors IL-1β and IL-6, as well as the apoptosis of the macrophage in Mtb infected RAW264.7 cells. Mechanism investigation showed that MptpB simultaneously hampered the NF-κB and MAPK signal pathways, evidenced by its blocking of p65, IKKα, Erk1/2, and p38 phosphorylation induced by Mtb infection. MptpB also inhibited host cell p53 expression. The results demonstrated that MptpB contributed to the survival of H37Rv by inhibiting host inflammatory responses and apoptosis through impeding the NF-κB and MAPK signal pathways and p53 expression in the macrophage.</p

Image_3_MptpB Promotes Mycobacteria Survival by Inhibiting the Expression of Inflammatory Mediators and Cell Apoptosis in Macrophages.PDF

<p>Tuberculosis is a severe contagious disease caused by Mycobacterium tuberculosis (Mtb). To develop new vaccines and medicine against TB, there is an urgent need to provide insights into the mechanisms by which Mtb induces tuberculosis. In this study, we found that secreted Mtb virulence factor MptpB significantly enhanced the survival of H37Rv in macrophages. MptpB suppressed the production of iNOS, the expression of inflammatory factors IL-1β and IL-6, as well as the apoptosis of the macrophage in Mtb infected RAW264.7 cells. Mechanism investigation showed that MptpB simultaneously hampered the NF-κB and MAPK signal pathways, evidenced by its blocking of p65, IKKα, Erk1/2, and p38 phosphorylation induced by Mtb infection. MptpB also inhibited host cell p53 expression. The results demonstrated that MptpB contributed to the survival of H37Rv by inhibiting host inflammatory responses and apoptosis through impeding the NF-κB and MAPK signal pathways and p53 expression in the macrophage.</p

Image_2_MptpB Promotes Mycobacteria Survival by Inhibiting the Expression of Inflammatory Mediators and Cell Apoptosis in Macrophages.PDF

<p>Tuberculosis is a severe contagious disease caused by Mycobacterium tuberculosis (Mtb). To develop new vaccines and medicine against TB, there is an urgent need to provide insights into the mechanisms by which Mtb induces tuberculosis. In this study, we found that secreted Mtb virulence factor MptpB significantly enhanced the survival of H37Rv in macrophages. MptpB suppressed the production of iNOS, the expression of inflammatory factors IL-1β and IL-6, as well as the apoptosis of the macrophage in Mtb infected RAW264.7 cells. Mechanism investigation showed that MptpB simultaneously hampered the NF-κB and MAPK signal pathways, evidenced by its blocking of p65, IKKα, Erk1/2, and p38 phosphorylation induced by Mtb infection. MptpB also inhibited host cell p53 expression. The results demonstrated that MptpB contributed to the survival of H37Rv by inhibiting host inflammatory responses and apoptosis through impeding the NF-κB and MAPK signal pathways and p53 expression in the macrophage.</p

Highly Efficient Electrochemiluminescence Resonance Energy Transfer System in One Nanostructure: Its Application for Ultrasensitive Detection of MicroRNA in Cancer Cells

The electrochemiluminesce (ECL) efficiency of luminous emitter can be enhanced by the means of electrochemiluminesce resonance energy transfer (ECL-RET) with a matched donor. However, generally, the donor and acceptor pairs were separated in different independent nanostructures, experiencing the challenging issues of limited energy transfer efficiency and luminous stability. Herein, we designed novel ECL-RET model within one nanostructure containing the donor of tris­(4,4′-dicarboxylicacid-2,2′-bipyridyl) ruthenium­(II) dichloride (Ru­(dcbpy)₃²⁺) and the acceptor of CdSe@ZnS quantum dots (QDs) for acting as the ECL emitter (QDs-Ru­(dcbpy)₃²⁺), which significantly reduced the energy loss and improved the ECL efficiency of QDs because of the short path of energy transmission. To demonstrate the proof-of-concept, the proposed QDs-Ru­(dcbpy)₃²⁺ was employed to construct a new kind of ECL biosensor that could achieve the ultrasensitive detection of microRNA-141 (miRNA-141) combining target recycling amplification and the double-output conversion strategies. Notably, the proposed double-output conversion strategy enabled a small number of miRNA to be successfully transferred into a large number of reporter DNA which could capture numerous QDs-Ru­(dcbpy)₃²⁺-labeled signal probes on the sensing surface to realize the ECL response to the logarithm of the concentration of miRNA-141. With the ultrahigh-efficient ECL-RET in one nanostructure and the dual amplification including target recycling as well as double-output conversion strategies, the proposed biosensor realized ultrasensitive detection of miRNA-141 and performed the concentration range from 100 aM to 10 pM and the estimated detection limit was 33 aM (<i>S</i>/<i>N</i> = 3). Impressively, this method can sensitively detect the miRNA-141 of human prostate cancer cells and provide a significant boost for the detection of other biomarkers in early cancer diagnosis and therapeutic monitoring