37 research outputs found

    Animal models of the placenta accreta spectrum: current status and further perspectives

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    Placenta accreta spectrum disorder (PAS) is a kind of disease of placentation defined as abnormal trophoblast invasion of part or all of the placenta into the myometrium, even penetrating the uterus. Decidual deficiency, abnormal vascular remodeling in the maternal–fetal interface, and excessive invasion by extravillous trophoblast (EVT) cells contribute to its onset. However, the mechanisms and signaling pathways underlying such phenotypes are not fully understood, partly due to the lack of suitable experimental animal models. Appropriate animal models will facilitate the comprehensive and systematic elucidation of the pathogenesis of PAS. Due to the remarkably similar functional placental villous units and hemochorial placentation to humans, the current animal models of PAS are based on mice. There are various mouse models induced by uterine surgery to simulate different phenotypes of PAS, such as excessive invasion of EVT or immune disturbance at the maternal–fetal interface, which could define the pathological mechanism of PAS from the perspective of the “soil.” Additionally, genetically modified mouse models could be used to study PAS, which is helpful to exploring the pathogenesis of PAS from the perspectives of both “soil” and “seed,” respectively. This review details early placental development in mice, with a focus on the approaches of PAS modeling. Additionally, the strengths, limitations and the applicability of each strategy and further perspectives are summarized to provide the theoretical foundation for researchers to select appropriate animal models for various research purposes. This will help better determine the pathogenesis of PAS and even promote possible therapy

    Solvent- And Base-Free Oxidation of 5-Hydroxymethylfurfural over a PdO/AlPO4-5 Catalyst under Mild Conditions

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    Funding Information: Financial support from the Natural Science Foundation of China under Contracts 21808163 and 21690083 is gratefully acknowledged. Publisher Copyright: © 2021 American Chemical Society.A solvent-free method was proposed to upgrade the biomass-derived compound 5-hydroxymethylfurfural (HMF). The oxidation of HMF to produce 2,5-furandicarboxylic acid (FDCA) has been examined in the presence of O2 without the addition of solvent and base. Different from the conversion of the aldehyde group on HMF as the initial oxidation step in H2O solvent, the hydroxyl group on HMF was first oxidized and FDCA was finally generated without the addition of solvent. The role of O2 is to replenish the consumption of active oxygen species on the catalyst surface. The oxidation of HMF to FDCA proceeded due to the solvent-free effect. A 83.6% FDCA selectivity at 38.8% HMF conversion was measured with a PdO/AlPO4-5 catalyst at 80 °C for 5 h and the reaction mechanism was proposed.Peer reviewe

    Efficient Selective Oxidation of 5-Hydroxymethylfurfural with Oxygen over a ZnCrAl Mixed Oxide Catalyst Derived from Hydrotalcite-like Precursor

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    Funding Information: The work was supported by the Natural Science Foundation of China (21808163). Publisher Copyright: © 2022 American Chemical Society. All rights reserved.Cr-doped ZnAl mixed oxide catalysts (Zn0.75CrAl-x-c) were obtained via calcining the Zn0.75CrAl-x hydrotalcite precursors and were applied in the selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA). Cr doping significantly enhanced the catalytic activity. A 95.1% 5-HMF conversion with an 88.1% FDCA selectivity was achieved over the Zn0.75CrAl-6-c catalyst at 130 °C under 0.6 MPa oxygen for 4 h. The good performance was associated with the high specific surface area and high oxygen vacancy concentration. Moreover, the Zn0.75CrAl-6-c catalyst was used for five cycles without a significant activity loss indicating excellent stability.Peer reviewe

    Selective production of 2-(tert-butyl)-3-methylphenol from depolymerization of enzymatic hydrolysis lignin with MoS2 catalyst

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    | openaire: EC/H2020/101006744/EU//EHLCATHOL This work is supported by the National Natural Science Foundation of China (21808163). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101006744. The content presented in this document represents the views of the authors, and the European Commission has no liability in respect of the content.Low selectivity and complex product distribution are the main challenges for the utilization of lignin. Herein, the selective production of 2-(tert-butyl)-3-methylphenol (TBC), an antioxidant in the polymer industry, from depolymerization of enzymatic hydrolysis lignin (EHL) on a hydrothermally synthesized MoS2 catalyst is studied. The total aromatic monomer yield is 124.1mg/g EHL and the selectivity of TBC is up to 40.3wt% in methanol at 280oC under 2MPa H2 for 6h. The FT-IR analysis of products reveals that MoS2 has a high activity for demethylation, dehydroxylation and alkylation, and the dimer conversions reveal that C-O and C-C bonds in EHL are broken with MoS2. The guaiacol and its derivants are identified as the intermediate for formation of TBC in EHL depolymerizaiton according to the effect of time on product distribution and monomer converison.Peer reviewe

    Defunctionalization of fructose and sucrose: iron-catalyzed production of 5-hydroxymethylfurfural from fructose and sucrose

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    A highly efficient iron-catalyzed production of 5-hydroxymethylfurfural (HMF) from sugar is reported. The dehydration of fructose and sucrose has been studied in the presence of different iron salts and co-catalysts. As a result, it was found that fructose and sucrose could be efficiently and selectively converted to HMF using a combination of environmentally friendly FeCl and tetraethyl ammonium bromide (EtNBr) as the catalytic system. For instance, 86% HMF yield at full conversion of fructose was obtained for 2 h at 90 ° C in air. The effects of catalyst concentration, reaction time and reaction temperature were investigated in detail. The electronic absorption spectra of different catalysts were recorded, and the FeClBr ion was considered as the active catalyst species

    Hydroxyapatite Supported Manganese Oxide as a Heterogeneous Catalyst for the Synthesis of 2, 5-Diformylfuran

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    Funding Information: The research was supported by the Natural Science Foundation of China (21808163 and 21690083). Publisher Copyright: © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.A series of hydroxyapatite (HAP) supports with different Ca/P ratios were synthesized to prepare the MnOx/HAP catalysts. A MnOx/HAP catalyst showed highly efficient conversion of 5-hydroxymethylfurfural (HMF) into 2, 5-diformylfuran (DFF) in toluene solvent under no-alkali condition. 86.4% conversion of HMF with 90.9% selectivity of DFF at 120 °C for 12 h under 1.0 MPa O2 over the MnOx/HAP-10.0-400 were obtained. The redox of Mn4+/Mn3+ improved the oxidation of 5-HMF to DFF by the lattice oxygen, and the lattice oxygen was replenished by adsorbing O2 molecules. The reusability tests were found the catalyst could be reused up to four cycles without notable loss of catalytic activity. The MnOx/HAP-10.0-400 was a stable and reusable material for further industrial exploration of DFF in an environmentally friendly way.Peer reviewe

    Highly selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran over an α-MnO2 catalyst

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    Selective oxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-diformylfuran (DFF) with molecular oxygen is realized with an α-MnO2 catalyst under mild conditions. In this work, α-MnO2 exhibited the best performance among the samples examined. Meanwhile, solvent shows a significant effect on the product selectivity and isopropanol is found good for improving the selectivity of DFF. 93.2% conversion of HMF was achieved at 140 °C for 4 h with 84.3% selectivity of DFF. Moreover, α-MnO2 catalyst keeps good reusability in recycling for five times. The reaction pathway indicated that the lattice oxygen species on α-MnO2 is involved in the selective oxidation of hydroxyl group in HMF molecule.Peer reviewe

    Catalytic Conversion of Enzymatic Hydrolysis Lignin into Cycloalkanes over a Gamma-Alumina Supported Nickel Molybdenum Alloy Catalyst

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    | openaire: EC/H2020/101006744/EU//EHLCATHOLThe efficient depolymerization and hydrodeoxygenation of enzymatic hydrolysis lignin are achieved in cyclohexane solvents over a gamma-alumina supported nickel molybdenum alloy catalyst in a single step. Under initial 3 MPa hydrogen at 320 °C, the highest overall cycloalkane yield of 104.4 mg/g enzymatic hydrolysis lignin with 44.4 wt% selectivity of ethyl-cyclohexane was obtained. The reaction atmosphere and temperature have significant effects on enzymatic hydrolysis lignin conversion, product type and distribution. The conversion of enzymatic hydrolysis lignin was also investigated over different nickel and molybdenum-based catalysts, and the gamma-alumina supported nickel molybdenum alloy catalyst exhibited the highest activity among those catalysts. To reveal the reaction pathways of alkylphenol hydrodeoxygenation, 4-ethylphenol was tested as a model compound. Complete conversion of 4-ethylphenol into cycloalkanes was achieved. A two-step mechanism of 4-ethylphenol dihydroxylation - hydrogenation is proposed, in which the benzene ring saturation is deemed as the rate-determining step.Peer reviewe

    N-Doped carbon nanotube encapsulated cobalt for efficient oxidative esterification of 5-hydroxymethylfurfural

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    Cobalt nanoparticles embedded in graphitic nitrogen-rich carbon nanotubes (Co/GCN) were prepared with a facile method and employed as an efficient catalyst for oxidative esterification of 5-hydroxymethylfurfural (HMF). The introduction of N species to carbon benefits the synergistic effects between the Co nanoparticles and nitrogen-doped carbon nanotube substrate, which modify the surface chemical state of the Co/GCN catalyst and create abundant active sites to improve the HMF conversion. The Co/GCN catalyst carbonized at 800 degrees C exhibited the best catalytic performance with a 95.8% yield of furan-2,5-dimethylcarboxylate (FDMC) at 98.6% HMF conversion under mild reaction conditions. The effect of acid-base properties of the catalyst on the HMF conversion was investigated and the reaction mechanism of the HMF oxidative esterification was proposed.Peer reviewe

    Enzymatic hydrolysis lignin dissolution and low-temperature solvolysis in ethylene glycol

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    | openaire: EC/H2020/101006744/EU//EHLCATHOL Funding Information: This work has received funding from the European Union’s Horizon 2020 research and innovation program , (BUILDING A LOW-CARBON, CLIMATE RESILIENT FUTURE: SECURE, CLEAN AND EFFICIENT EN-ERGY) under Grant Agreement No 101006744. The content presented in this document represents the views of the authors, and the European Commission has no liability in respect of the content. Y.S. Sang and G. Li would like to express their gratitude to both the China Scholarship Council ( 202006250156 , 202208320030 ) and the EU-101006744 project. Publisher Copyright: © 2023 The Author(s)The dissolution and solvolysis processes of enzymatic hydrolysis lignin (EHL) in ethylene glycol are investigated. Ethylene glycol exhibits high EHL solubility and achieves complete EHL dissolution at room temperature. Gaussian simulation reveals that van de Waals interactions between ethylene glycol and EHL, including C-H⋯O and lone pairâ‹ŻÏ€ interactions, break the π-π stacking in EHL, achieving complete EHL dissolution. EHL is partly depolymerized in ethylene glycol at 200 °C even without a catalyst due to the strong van de Waals interactions. When NaOH and Ni are used as co-catalysts, EHL is efficiently depolymerized at 200 °C, and the overall monomer yield reaches 18.8 wt%. Fourier transform infrared spectroscopy (FT-IR) and molecular dynamics simulation results indicate that the adsorption of ethylene glycol over Ni surface hinders the adsorption of lignin fragments and monomers. Hence, EHL catalytic solvolysis in ethylene glycol occurs in the liquid phase, where OH− of NaOH promotes the EHL linkage breakage and active hydrogen atoms formed on Ni surface stabilize the active monomers.Peer reviewe
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