The efficient catalytic conversion of lignin represents a critical challenge in biomass valorization, primarily due to the inherent difficulty in selectively depolymerizing lignin while maintaining the structural integrity of cellulose and hemicellulose. Herein, we present an innovative approach involving the synthesis of ionic liquid polyoxometalate (IL-POM) catalysts, which integrate both redox-active and Lewis acid sites, and are further modified with a choline chloride monomer. Among the synthesized catalysts, ChHPMoAlVO demonstrated exceptional catalytic performance, achieving an aromatic compound yield of 16.
View Article and Find Full Text PDFThe efficient utilization of lignin, a pivotal component of lignocellulosic biomass, is crucial for advancing sustainable biorefinery processes. However, optimizing lignin valorization remains challenging due to its intricate structure and susceptibility to undesirable reactions during processing. In this study, we delve into the impact of various pretreatment agents on birch lignin, aiming to enhance its catalytic oxidation and depolymerization under polyoxometalates (POMs) catalysis.
View Article and Find Full Text PDFThis study focused on extracting holocellulose from Changbai larch waste, which is rich in hexose and beneficial for furan chemicals production. Various alkaline deep eutectic solvents (DESs) was applied in the extraction of holocellulose. DES composed of lysine (Lys) and 2-aminoethanol (MEA) with strong alkalinity had a superior ability to remove lignin, and the purity of holocellulose could reach 82.
View Article and Find Full Text PDFUsing deep eutectic solvents (DES) to pretreat wheat straw (WS) and extract lignin-containing nanocellulose (LCNC). Acrylic acid/choline chloride (AA/ChCl) polymerizable deep eutectic solvents (PDES) were used as the primary polymerization network, combined with polyvinyl alcohol (PVA). Lignocellulose nanocrystals (LCNC) oxidized by sodium periodate were prepared as dialdehyde-based nanocellulose (DCNC) to serve as the crosslinking agent.
View Article and Find Full Text PDFLignin serves as a primary abundant source of renewable aromatic compounds. Achieving efficient breakdown of lignin and retaining its aromatic properties is highly desirable but remains a challenging task. To address this challenge, we synthesized Anderson-type polyoxometalate (POM) catalysts, particularly [CTAC][CoMo].
View Article and Find Full Text PDFA convenient copper-catalyzed three-component radical-based fluoroalkylphosphorothiolation of terminal alkynes with (PrO)P(O)SH and fluoroalkylation reagent for the synthesis of a variety of ()-β-fluoroalkyl vinyl phosphorothioates with excellent regioselectivity and stereoselectivity has been developed. All the starting materials used in this reaction are highly stable and readily available. Thus, this process features with mild reaction conditions, simple operation and good functional group tolerance (>40 examples).
View Article and Find Full Text PDFLignin, a complex and abundant polymer present in lignocellulosic biomass, holds immense potential as a renewable source for the production of valuable aromatic compounds. However, the efficient depolymerization of lignin into these compounds remains a formidable challenge. Here, we present a promising solution by harnessing polyoxometalates (POMs) catalysts, which exhibit improved catalytic performance and selectivity.
View Article and Find Full Text PDFLignocellulose, composed of cellulose, hemicellulose, and lignin, holds immense promise as a renewable resource for the production of sustainable chemicals and fuels. Unlocking the full potential of lignocellulose requires efficient pretreatment strategies. In this comprehensive review, efforts were taken to survey the latest developments in polyoxometalates (POMs)-assisted pretreatment and conversion of lignocellulosic biomass.
View Article and Find Full Text PDFConversion of renewable lignin into bio-aromatic chemicals offers a sustainable pathway to increase biorefinery profitability. However, the catalytic transformation of lignin into monomers remains a highly challenging task due to the complexity and stability of the lignin structure. In this study, a series of micellar molybdovanadophosphoric polyoxometalate (POM) catalysts, (CTA)HPMoVO (n = 1-5), were prepared by the ion exchange method and applied as oxidative catalysts for birch lignin depolymerization.
View Article and Find Full Text PDFDeveloping renewable biomass resources is an urgent task to reduce climate change. Lignin, the only renewable aromatic feedstock present in nature, has attracted considerable global interest in its transformation and utilization. However, the complexity of lignin's structure, uncertain linkages, stability of side chain connection, and inevitable recondensation of reaction fragments make lignin depolymerization into biofuels or platform chemicals a daunting challenge.
View Article and Find Full Text PDFBackground: The purpose of this study is to evaluate the accuracy of prenatal MRI in diagnosing choledochal cysts (CDC), evaluate the sensitivity and specificity of MRI signs in the diagnosis of fetal CDC, and first compare the trend of size of CC between prenatal and postpartum.
Methods: A total of 18 fetal who were diagnosed with CDCs through prenatal MRI were enrolled in the study. We summarized and analyzed the prenatal clinical data and prognosis information of prenatal and postpartum surgery, then compared the sensitivity, specificity, and diagnostic accuracy of various signs of MRI and postpartum MRCP diagnosis of CC.
This study aimed to in the management of Kasabach-Merritt phenomenon (KMP), a severe thrombocytopenic coagulopathy that occurs in the presence of an enlarging vascular tumor. Here, we retrospectively evaluated 12 patients with KMP in Guangzhou Women and Children's Medical Center, Guangzhou Medical University, from 2017 to 2021. 12 patients, including 7 females and 5 males, were identified.
View Article and Find Full Text PDFThe selective recovery of Gd(iii) from wastewater is very meaningful for the prospective development of economics and the environment. To overcome disadvantages of poor adsorption capacity, low selectivity and complex preparation process in conventional adsorbents, herein a new ionic imprinted carboxymethyl chitosan (CMC) sponge functionalized by hyperbranched polyethyleneimine (PEI) with a 3D network structure (PEI-CMC-IIS) was successfully prepared and applied in the selective adsorption of Gd(iii). The PEI-CMC-IIS is endowed with lots of amino groups due to the combination of biomass CMC with highly branched PEI, which is helpful for the adsorption of Gd(iii).
View Article and Find Full Text PDFThis paper focuses on the trajectory tracking guidance problem for the Terminal Area Energy Management (TAEM) phase of the Reusable Launch Vehicle (RLV). Considering the continuous state and action space of this guidance problem, the Continuous Actor-Critic Learning Automata (CACLA) is applied to construct the guidance strategy of RLV. Two three-layer neuron networks are used to model the critic and actor of CACLA, respectively.
View Article and Find Full Text PDFPurpose: We aimed to identify clinical and computed tomography (CT) features that distinguish among cystic congenital pulmonary airway malformations (CPAMs) and offer new management strategies.
Methods: We retrieved data on 145 children (85 male, 60 female; median age, 14 months) with pathologically confirmed cystic CPAMs from 2008 to 2018 and retrospectively analyzed the clinical and CT characteristics.
Results: Of the 145 patients, 54 had type 1, 72 had type 2, and 19 had type 4 cystic CPAMs.
The study aimed to investigate the effect of five inactive yeasts on the metabolites of Chardonnay dry white wines vinified in 2016 in Shacheng Manor Wine Co. Ltd., Hebei province, China.
View Article and Find Full Text PDFIt is of great importance to develop new pathways for low-cost, high-selectivity conversion of lignin into aromatics. In this work, a series of cesium exchanged and transition-metal substituted heterogeneous polyoxometalates were prepared and applied as efficient catalysts for lignin depolymerization. The catalytic oxidation of lignin has been monitored by GPC, 2D NMR HSQC, and GC/MS technologies, and the reaction pathway was also confirmed by the examination with a dimeric β-O-4 lignin model compound.
View Article and Find Full Text PDFThe aim of this study was to explore the catalytic performance of the oxidative depolymerization of enzymatic hydrolysis lignin from cellulosic ethanol fermentation residue by different vanadium substituted Keggin-type polyoxometalates (K₅[SiVWO], K₆[SiV₂WO], and K₆H[SiV₃W₉O]). Depolymerized products were analyzed by gel permeation chromatography (GPC), gas chromatography⁻mass spectrometer (GC/MS), and two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR) analysis. All catalysts showed an effective catalytic activity.
View Article and Find Full Text PDFMedicine (Baltimore)
December 2018
This study aims to analyze and summarize the imaging features of spinal atypical teratoid/rhabdoid tumors (AT/RT) in children.Imaging features in 8 children with spinal AT/RT confirmed by surgical pathology were retrospectively analyzed. All patients had underwent total spine 3.
View Article and Find Full Text PDFInstantaneous and noninvasive temperature measurements are important when laser thermotherapy or welding is performed. A noninvasive nanosecond-resolved magnetic nanoparticle (MNP) temperature measurement system is described in which a transient change in temperature causes an instantaneous change in the magnetic susceptibilities of the MNPs. These transient changes in the magnetic susceptibilities are rapidly recorded using a wideband magnetic measurement system with an upper frequency limit of 0.
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