Sustainable depolymerization of lignin into aromatic compounds using amphiphilic Anderson-type polyoxometalate catalysts.

Lignin 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]2[CoMo6]. We then investigated the effectiveness of the POM catalysts in the oxidative depolymerization of larch lignin. Under conditions of 160 °C, 1.0 MPa oxygen atmosphere, and a catalyst-to-substrate ratio of 1:5, we achieved a monomer yield of phenolic compounds at 12.43 wt%. The unsaturated coordination sites of Mo5+ within the catalysts were identified as active sites, facilitating enhanced O2 adsorption and activation. The enhanced O2 adsorption significantly influenced the production of aromatic monomers from lignin. We observed that the catalysts effectively cleaved CC bonds in ß-O-4 dimer compounds using lignin dimer model compounds. Notably, the [CTAC]2[CoMo6] catalyst exhibited excellent stability across five cycles, maintaining its high efficiency in lignin depolymerization. This indicates that Anderson-type POM-based catalysts exhibit potential for sustainable conversion of biomass into valuable compounds and for enhancing lignin valorization processes.

Copper-Catalyzed Fluoroalkylphosphorothiolation of Alkynes for the Synthesis of (E)-ß-Fluoroalkyl Vinyl Phosphorothioates.

A convenient copper-catalyzed three-component radical-based fluoroalkylphosphorothiolation of terminal alkynes with (iPrO)2P(O)SH and fluoroalkylation reagent for the synthesis of a variety of (E)-ß-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). Furthermore, this modular reaction system allows the late-stage functionalization of bioactive molecules.

Bimetallic polyoxometalates catalysts for efficient lignin depolymerization: Unlocking valuable aromatic compounds from renewable feedstock.

Lignin, 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. We synthesized a series of NixCoy@POMs catalysts (POMs: CsPW or CsPMo) and explored their application in the depolymerization of pine lignin, aiming to investigate the influence of different metal species and doping ratios of POMs on catalytic performance. Through meticulous optimization of reaction conditions, we achieved significant yields of valuable aromatic compounds, including methyl vanillate, vanillin, and 4-hydroxy-3-methoxyacetophenone. Furthermore, the Ni0.75Co0.75@CsPMo catalyst demonstrated exceptional efficacy in catalyzing the cracking process of C-C and/or C-O bonds in a ß-O-4 dimer model compound. Notably, our catalyst exhibited outstanding stability over five cycles, underscoring its suitability as an effective heterogeneous catalyst for cyclic lignin depolymerization. This study sheds light on the potential of POMs-based catalysts for advancing lignin valorization and offers new avenues for sustainable biomass conversion into valuable chemicals.

Advances in Polyoxometalates as Electron Mediators for Photocatalytic Dye Degradation.

The increasing concerns over the environment and the growing demand for sustainable water treatment technologies have sparked substantial interest in the field of photocatalytic dye removal. Polyoxometalates (POMs), known for their intricate metal-oxygen anion clusters, have received considerable attention due to their versatile structures, compositions, and efficient facilitation of photo-induced electron transfers. This paper provides an overview of the ongoing research progress in the realm of photocatalytic dye degradation utilizing POMs and their derivatives. The details encompass the compositions of catalysts, catalytic efficacy, and light absorption propensities, and the photocatalytic mechanisms inherent to POM-based materials for dye degradation are exhaustively expounded upon. This review not only contributes to a better understanding of the potential of POM-based materials in photocatalytic dye degradation, but also presents the advancements and future prospects in this domain of environmental remediation.

Recent Advances in Application of Polyoxometalates in Lignocellulose Pretreatment and Transformation.

Lignocellulose, 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. An outstanding finding highlighted in this review is that the deformation of the cellulose structure from I to II accompanied by the removal of xylan/lignin through the synergistic effect of ionic liquids (ILs) and POMs resulted in a significant increase in glucose yield and improved cellulose digestibility. Furthermore, successful integration of POMs with deep eutectic solvents (DES) or γ-valerolactone/water (GVL/water) systems has demonstrated efficient lignin removal, opening avenues for advanced biomass utilization. This review not only presents the key findings and novel approaches in POMs-based pretreatment but also addresses the current challenges and prospects for large-scale industrial implementation. By offering a comprehensive assessment of the progress in this field, this review serves as a valuable resource for researchers and industry professionals aiming to harness the potential of lignocellulosic biomass for sustainable chemical and fuel production.

Fabrication and application of amphiphilic polyoxometalate catalyst (CTA)nH5-nPMo10V2O40 for transformation of lignin into aromatic chemicals.

Conversion 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)nH5-nPMo10V2O40 (n = 1-5), were prepared by the ion exchange method and applied as oxidative catalysts for birch lignin depolymerization. These catalysts showed efficient cleavage of C-O/C-C bonds in lignin, and the introduction of an amphiphilic structure facilitated the generation of monomer products. The best catalytic activity was observed at 150 °C within 150 min under a 1.5 MPa oxygen atmosphere over (CTA)1H4PMo10V2O40, which yielded a maximum lignin oil yield of 48.7 % and lignin monomer yield of 13.5 %. We also employed phenolic and nonphenolic lignin dimer model compounds to explore the reaction pathway and demonstrated the selective cleavage of CC and/or CO lignin bonds. Moreover, these micellar catalysts have excellent recyclability and stability as heterogeneous catalysts, which can be used up to five times. The application of amphiphilic polyoxometalate catalysts facilitates the valorization of lignin, and we expect to develop a novel and practical strategy for harvesting aromatic compounds.

Structural Characteristics-Reactivity Relationships for Catalytic Depolymerization of Lignin into Aromatic Compounds: A Review.

Developing 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. Therefore, understanding the structural characteristics and reactivity relationships is crucial for achieving high-value utilization of lignin. In this review, we summarize the key achievements in the field of lignin conversion with a focus on the effects of the ß-O-4 content, S/G ratio, lignin sources, and an "ideal" lignin-catechyl lignin. We discuss how these characteristics influence the formation of lignin monomer products and provide an outlook on the future direction of lignin depolymerization.

Accuracy of Magnetic Resonance Imaging in Prenatal Diagnosis of Choledochal Cysts: A Single-Center Retrospective Analysis.

Background: 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. Finally, we tried to compare the earliest prenatal detection of common bile duct cysts with the size of surgery, and calculated the growth rate of common bile duct cysts for the first time. Results: All 18 patients were delivered in our institution. Among these patients, 14 were confirmed with CDCs after postpartum surgery, two patients had CDCs that disappeared, and two patients were confirmed with cystic biliary atresia (CBA) through the Kasai operation. Furthermore, 13 patients with CDCs and two patients with CBA underwent MRCP before the operation, and one patient with CDCs ruptured at birth and underwent ultrasound diagnosis. The sensitivity and diagnostic compliance of prenatal MRI signs for the location were higher when compared to postnatal MRCP (100% vs. 76.9% and 83.3% vs. 66.7%): the cyst was located at the porta hepatis, which was higher than the lowest edge of the liver, and parallel to the hepatoduodenal ligament. Conclusion: Prenatal MRI is higher than that of US for diagnosing CDCs, specifically in identifying the location of the cyst and confirming the origin of the cyst. The length, width, and size of the CDC become slightly bigger in our study.

Combination therapy for pediatric patients with Kasabach-Merritt phenomenon: A single-center retrospective study.

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. Tumors were located in the leg (n = 4), neck (n = 1), face (n = 3), chest wall (n = 1), back (n = 2), and retroperitoneum (n = 1). A plaque-like lesion with ecchymosis was the most common cutaneous manifestation. All the patients underwent embolization therapy. Nine patients received steroid treatment and 7 patients were administered with sirolimus. The mean duration of treatment was 1.6 months. All the patients reported in this study were alive when discharged. Embolization combined with steroid and sirolimus appears effective in patients with KMP, as well as in those who experienced disease recurrence. However, a long-term follow-up of the children cured of KMP will be necessary to monitor its recurrence and improve the outcome.

Rational fabrication of a new ionic imprinted carboxymethyl chitosan-based sponge for efficient selective adsorption of Gd(iii).

The 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). The imprinting sites are located at the surface of channels in PEI-CMC-IIS, which can achieve the adsorption specificity to Gd(iii) and improve adsorption capacity. It is found that the maximum adsorption capacity of PEI-CMC-IIS is 38.64 mg g-1 at pH = 7. Meanwhile, the selectivity tests suggest that the PEI-CMC-IIS presents preferential adsorption for Gd(iii) with a distribution coefficient of 437.5 mL g-1. Furthermore, the PEI-CMC-IIS displays excellent reusing and regeneration ability. Our findings will bring about potential application in fabrication of other high-efficiency adsorbents for selective adsorption of Gd(iii).

CACLA-Based Trajectory Tracking Guidance for RLV in Terminal Area Energy Management Phase.

This 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. The weight vectors of the critic are updated by the model-free Temporal Difference (TD) learning algorithm, which is improved by eligibility trace and momentum factor. The weight vectors of the actor are updated based on the sign of TD error, and a Gauss exploration is carried out in the actor. Finally, a Monte Carlo simulation and a comparison simulation are performed to show the effectiveness of the CACLA-based guidance strategy.

Computed tomography features can distinguish type 4 congenital pulmonary airway malformation from other cystic congenital pulmonary airway malformations.

PURPOSE: 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. Significantly more male patients had type 4 CPAMs. Type 2 CPAMs had a higher frequency of combined malformations and prenatal diagnosis than types 1 and 4. The median diameter of cystic CPAMs was 2.8 cm; that of type 1, 2, and 4 was 4.6, 1.5, and 8.1 cm, respectively. Regression analysis showed that a cyst of >7.9 cm in diameter was likely to be type 4, that of <2.8 cm was likely to be type 2, and that of 2.8-7.9 cm was likely to be type 1. Smaller cysts were more likely to be type 2 and larger cysts were more likely to be type 4. The incidence of pneumonia was higher in type 2 than in types 4 and 1. The frequency of mediastinal shift and pneumothorax was statistically significant, and both were more common in type 4. CONCLUSION: A cyst of >7.9 cm in diameter, mediastinal shift, and pneumothorax were the most important characteristics of type 4 CPAMs. CT features can distinguish type 4 CPAM from other cystic CPAMs.

Analysis of metabolites in chardonnay dry white wine with various inactive yeasts by 1H NMR spectroscopy combined with pattern recognition analysis.

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. In this research, proton nuclear magnetic resonance (NMR) spectroscopy coupled multivariate analysis (1H NMR-PCA/PLS-DA) were applied to identify and discriminate the different wine products. The results of principle component analysis (PCA) showed that there was significant difference between the metabolites of sample wines with different inactive yeasts, among them, the content of polyols, organic acids, amino acids and choline was notably influenced. The results of partial least squares discrimination analysis (PLS-DA) confirmed that the metabolites contributed to the discrimination of the wines were 2,3-butanediol, ethyl acetate, malic acid, valine, succinic acid, lactic acid, tartaric acid, glycerol, gallic acid, choline, proline, and alanine.

Catalytic depolymerization of lignin over cesium exchanged and transition-metal substituted heterogeneous polyoxometalates.

It 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 ß-O-4 lignin model compound. Under optimal conditions, these catalysts showed high activity toward oxidative cleavage of ß-O-4 linkages, as well as ß-5 and ß-ß CC linkages. In particular, the Co substituted polyoxometalates gave high yield of ca. 9.58% monomeric products at 150°C within 3h under an oxygen atmosphere. Results demonstrated the catalyst was easily separated from products and could be repeatedly used at least five cycles without significant loss of activity. Further, the possible reaction mechanism was proposed by a two-step oxygen-based electron transfer and oxygen transfer reaction mechanism. The design and application of the multifunctional POMs based heterogeneous catalytic system make this strategy of great interest in the production of aromatic products from lignin and inspire a new insight to utilize the entire lignocellulosic biomass.

Oxidative Depolymerization of Cellulolytic Enzyme Lignin over Silicotungvanadium Polyoxometalates.

The 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[SiVW11O40], K6[SiV2W10O40], and K6H[SiV3W9O40]). 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. The best result, concerning the lignin conversion and lignin oil production, was obtained by K6[SiV2W10O40], and the highest yield of oxidative depolymerization products of 53 wt % was achieved and the main products were monomer aromatic compounds. The HSQC demonstrated that the catalysts were very effective in breaking the ß-O-4 structure, the dominant linkage in lignin, and the GPC analysis demonstrated that the molecular of lignin was declined significantly. These results demonstrate the vanadium substituted silicotungstic polyoxometalates were of highly active and stable catalysts for lignin conversion, and this strategy has the potential to be applicable for production of value-added chemicals from biorefinery lignin.

Imaging features of spinal atypical teratoid rhabdoid tumors in children.

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 3.0 T magnetic resonance imaging (MRI) and 64-slice spiral computed tomography (CT). Among these 8 patients, head MR non-enhanced and spinal enhanced scanning was applied to 5 patients, while CT examination was applied to 3 patients.All 8 patients were characterized by cauda equina syndrome. The lesions of 7 patients were in the thoracolumbar spinal junction, while the lesion of the remaining patient was in the lumbar spine. Furthermore, among these patients, the lesions of 5 patients were limited to the intraspinal canal (1 lesion in the epidural space, and 4 lesions in the subdural space), while the lesions of 3 patients invaded the paravertebra (2 lesions in the epidural space and 1 lesion in the subdural space). Three or more spinal segments were invaded by tumors in 7 patients, while sacral canal was affected in 5 patients. All 8 patients experienced bleeding in the tumors. Enhanced MRI revealed meningeal enhancement in 6 patients, and bilateral nerve root enhancement in 4 patients. The masses in 3 patients brought damages to the intervertebral foramen or sacral pore. The lesion of 1 patient was featured by skip growth. One patient had total spinal metastasis and 3 had hydrocephalus. The masses in 2 patients had a slightly low density when detected by CT, and enhanced scanning revealed a mild to moderate enhancement.Spinal AR/TR had the following characteristics: children were characterized by cauda equina syndrome; the mass that invaded the thoracolumbar spinal junction and the extramedullary space of multiple segments grew along the spinal longitudinal axis; bleeding mass was revealed in MRI imaging; meninges, nerve root, and sacral canal metastases occurred. The gold standard for the definite diagnosis of AT/RT is biopsy combined with immunohistochemistry.

Nanosecond-resolved temperature measurements using magnetic nanoparticles.

Instantaneous 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 0.5 GHz. The Langevin function (the thermodynamic model characterizing the MNP magnetization process) is used to obtain the temperature information. Experiments showed that the MNP DC magnetization temperature-measurement system can detect a 14.4 ns laser pulse at least. This method of measuring temperature is likely to be useful for acquiring the internal temperatures of materials irradiated with lasers, as well as in other areas of research.