Electrical tree properties of grafted polypropylene studied by electro-luminescence and free radical excitation analysis.

The electrical tree in grafted polypropylene (PP) is inhibited compared with that of pure PP. To understand the free radicals that are generated during the treeing process, we study the electron paramagnetic resonance (EPR) spectra. Additionally, to provide a clearer explanation of the suppression of electrical trees, this research uses electroluminescence (EL) and excitation computation. These methods help us to observe the movement of electrons and to understand the geometric and electronic structures involved. In pure PP, the energy required to excite the electrons is approximately the same as the band gap of PP while electrons are easier to be excited in grafted PP than in pure PP, because the band gap is narrower. As a result, though the electrical tree length is shorter in PP-g-MMA, the EPR signal is more intense because of the uneven distribution of electrons.

Association of the triglyceride glucose-body mass index with the extent of coronary artery disease in patients with acute coronary syndromes.

BACKGROUND: Studies have shown that insulin resistance is strongly associated with the development of cardiovascular disease, and the triglyceride glucose-body mass index (TyG-BMI index) is considered to be a reliable surrogate marker of insulin resistance. There are limited studies on the relationship between TyG-BMI index and the extent of coronary artery disease in patients with acute coronary syndrome (ACS). This study aimed to investigate the relationship between TyG-BMI index and the extent of coronary artery disease in patients with ACS. METHODS: Overall, 2,317 patients with ACS who underwent percutaneous coronary intervention at the Affiliated Hospital of Zunyi Medical University were included in this study. The TyG-BMI index was grouped according to the tertile method. The extent of coronary artery disease in patients with ACS was quantitatively assessed using the SYNTAX score, which was categorised as low (≤ 22), intermediate (23-32), and high risk (≥ 33). RESULTS: In the overall population, multivariate logistic regression analyses showed that TyG-BMI index was associated with mid/high SYNTAX score in patients with ACS (odds ratio [OR] = 1.0041; 95% confidence interval [CI] = 1.0000-1.0079; p = 0.0310). Subgroup analyses showed that TyG-BMI index was an independent risk factor for mid/high SYNTAX score in female ACS patients after adjusting for multiple confounders (OR = 1.0100; 95% CI = 1.0000-1.0200; p = 0.0050), and that the risk of mid/high SYNTAX score was 2.49 times higher in the T3 group (OR = 2.4900; 95% CI = 1.2200-5.0600; p = 0.0120). Restricted cubic spline analysis showed a linear correlation between TyG-BMI index and complex coronary artery disease (SYNTAX score > 22) in women with ACS. In female ACS patients, inclusion of the TyG-BMI index did not improve the predictive power of the underlying risk model (net reclassification improvement: 0.0867 [-0.0256-0.1989], p = 0.1301; integrated discrimination improvement: 0.0183 [0.0038-0.0329], p = 0.0135). CONCLUSIONS: TyG-BMI index is linearly associated with the degree of complex coronary artery disease in female ACS patients. However, the inclusion of the TyG-BMI index did not improve the predictive power of the underlying risk model for female ACS patients.

Risk prediction of second primary malignant tumor in primary differentiated thyroid cancer patients: a population-based study.

PURPOSE: To investigate the risk factors of second primary malignant tumor (SPMT) in patients with differentiated thyroid cancer (DTC) and establish a competing risk nomogram to predict the probability of SPMT occurrence. METHODS: We retrieved data from the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with DTC between 2000 and 2019. The Fine and Gray subdistribution hazard model was employed to identify SPMT risk factors in the training set and develop a competing risk nomogram. Model evaluation was performed using area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA). RESULTS: A total of 112,257 eligible patients were included in the study and randomized into a training set (n = 112,256) and a validation set (n = 33,678). The cumulative incidence rate of SPMT was 15% (n = 9528). Age, sex, race, tumor multifocality, and TNM stage were independent risk factors of SPMT. The calibration plots showed good agreement between the predicted and observed SPMT risks. The 10-year AUCs of the calibration plots were 70.2 (68.7-71.6) in the training set and 70.2 (68.7-71.5) in the validation set. Moreover, DCA showed that our proposed model resulted in higher net benefits within a defined range of risk thresholds. The cumulative incidence rate of SPMT differed among risk groups, classified according to nomogram risk scores. CONCLUSION: The competing risk nomogram developed in this study exhibits high performance in predicting the occurrence of SPMT in patients with DTC. These findings may help clinicians identify patients at distinct levels of risk of SPMT and develop corresponding clinical management strategies.

A large and overlooked Cd source in karst areas: The migration and origin of Cd during soil formation and erosion.

There is increasing concern regarding the substantial enrichment of Cd during the weathering of carbonate rocks and subsequent risks posed to the ecological environment and food security in karst areas. However, the incomplete understanding of Cd migration mechanisms and material sources restricts soil pollution control and land management. This study investigated the migration regulation of Cd during soil formation and erosion in karst areas. The results demonstrate that soil Cd concentration and bioavailability are both significantly higher in alluvium compared with those in eluvium. This increase is primarily attributed to the chemical migration of active Cd, rather than the mechanical migration of inactive Cd. Additionally, we analyzed the Cd isotopic characteristics of rock and soil samples. The isotopic composition of the alluvial soil was -0.18 ‰ ± 0.01 ‰, which is obviously heavier than the δ114/110Cd value of the eluvium (-0.78 ‰ ± 0.06 ‰). The Cd isotopic fingerprint revealed that the active Cd in the alluvium of the study profile was probably derived from the corrosion of carbonate rocks rather than by eluviation of the eluvium. Moreover, Cd tends to occur in soluble mineral components of carbonate rocks rather than in residues, which suggests that carbonate weathering has a great potential to release active Cd into the environment. It is estimated that the Cd release flux caused by carbonate weathering is 5.28 g Cd km-2 yr-1, accounting for 9.30 % of the anthropogenic Cd flux. Therefore, the corrosion of carbonate rocks is a substantial natural Cd source and poses significant potential risks to the ecological environment. It is suggested that the contribution of Cd from natural sources should be considered during ecological risk assessments and studies of the global Cd geochemical cycle.

Development of a novel hypoxia-immune-related LncRNA risk signature for predicting the prognosis and immunotherapy response of colorectal cancer.

Background: Colorectal cancer (CRC) is one of the most common digestive system tumors worldwide. Hypoxia and immunity are closely related in CRC; however, the role of hypoxia-immune-related lncRNAs in CRC prognosis is unknown. Methods: Data used in the current study were sourced from the Gene Expression Omnibus and The Cancer Genome Atlas (TCGA) databases. CRC patients were divided into low- and high-hypoxia groups using the single-sample gene set enrichment analysis (ssGSEA) algorithm and into low- and high-immune groups using the Estimation of STromal and Immune cells in MAlignant Tumours using Expression data (ESTIMATE) algorithm. Differentially expressed lncRNAs (DElncRNAs) between low- and high-hypoxia groups, low- and high-immune groups, and tumor and control samples were identified using the limma package. Hypoxia-immune-related lncRNAs were obtained by intersecting these DElncRNAs. A hypoxia-immune-related lncRNA risk signature was developed using univariate Cox regression and least absolute shrinkage and selection operator (LASSO) analyses. The tumor microenvironments in the low- and high-risk groups were evaluated using ssGSEA, ESTIMATE, and the expression of immune checkpoints. The therapeutic response in the two groups was assessed using TIDE, IPS, and IC50. A ceRNA network based on signature lncRNAs was constructed. Finally, we used RT-qPCR to verify the expression of hypoxia-immune-related lncRNA signatures in normal and cancer tissues. Results: Using differential expression analysis, and univariate Cox and LASSO regression analyses, ZNF667-AS1, LINC01354, LINC00996, DANCR, CECR7, and LINC01116 were selected to construct a hypoxia-immune-related lncRNA signature. The performance of the risk signature in predicting CRC prognosis was validated in internal and external datasets, as evidenced by receiver operating characteristic curves. In addition, we observed significant differences in the tumor microenvironment and immunotherapy response between low- and high-risk groups and constructed a CECR7-miRNA-mRNA regulatory network in CRC. Furthermore, RT-qPCR results confirmed that the expression patterns of the six lncRNA signatures were consistent with those in TCGA-CRC cohort. Conclusion: Our study identified six hypoxia-immune-related lncRNAs for predicting CRC survival and sensitivity to immunotherapy. These findings may enrich our understanding of CRC and help improve CRC treatment. However, large-scale long-term follow-up studies are required for verification.

Fabrication of wide temperature FexCe1-xVO4 modified TiO2-graphene catalyst with excellent NH3-SCR performance and strong SO2/H2O tolerance.

Selective catalytic reduction of NO with NH3 (NH3-SCR) is one of the most common technique for elimination of NOx. The promotional effect of Fe additive on the NH3-SCR activity of the CeVO4/TiO2-graphene (GE) is systematically studied. The results exhibited that the low-temperature NOx conversion could be enhanced dramatically via the addition of Fe and Fe0.5Ce0.5VO4/TiO2-GE displayed the highest conversion of NOx in the wide temperature window (200-400 °C). It is because that Fe3+ + Ce3+ ↔ Fe2+ + Ce4+ facilitated the oxidization of NO to NO2 at low temperature and led to the "Fast SCR," thereby raising the SCR performance. What is more, the introduction of Fe enhanced redox ability, the surface relative percentage of Ce3+, V5+ and the chemical adsorbed oxygen. Furthermore, the high surface concentration of Ce3+ species can produce more active oxygen and leads to the "Fast SCR" reaction. In addition, the Fe0.5Ce0.5VO4/TiO2-GE catalyst showed excellent H2O/SO2 tolerance, which may be due to the decomposition of ammonium bisulphite under high temperature and the hydrophobicity of graphene. What is more, it displayed outstanding the stability. This work would provide theoretical reference for the practical application of NOx abatement via NH3-SCR.

Influence of different preparation methods on the activity of Ce and Mo co-doped ZSM-5 catalysts for the selective catalytic reduction of NOx by NH3.

The Ce-doped different MoO3 [conventional molybdenum oxide (con-MoO3) or nano molybdenum oxide (nano-MoO3) and synthetic molybdenum oxide (syn-MoO3)] modification of ZSM-5 catalyst synthesized by different preparation methods (the combination of grinding and ion-exchange method and the combination of impregnation and ion-exchange method) was studied on selective catalytic reduction (SCR) of NOx with NH3. The results demonstrated that the SCR performance of the prepared Ce-doped syn-MoO3 modification of ZSM-5 catalyst [Ce(0.9%)-syn-MoO3(6%)/ZSM-5] by the combination of impregnation and ion-exchange method was better than Ce-doped con-MoO3 modification of ZSM-5 [Ce(0.9%)-con-MoO3(6%)/ZSM-5] and Ce-doped nano-MoO3 modification of ZSM-5 [Ce(0.9%)-nano-MoO3(6%)/ZSM-5] via the combination of grinding and ion-exchange method, especially when the temperature window is 200-350 °C. That is because it is easy to form Mo-O-Al by the smaller sized MoO3 more easily interacting well with Brønsted acid under calcining temperature, which results in the decrease of Brønsted acid sites in the catalyst. Combing with the binding energy of Mo for all the catalysts, the combination of Mo and Al (Mo-O-Al) altered the chemical environment around the Mo species. Furthermore, Ce(0.9%)-syn-MoO3(6%)/ZSM-5 exhibited excellent sulfur resistance.

Multicomponent Cascade Reaction by Metal-Free Aerobic Oxidation for Synthesis of Highly Functionalized 2-Amino-4-coumarinyl-5-arylpyrroles.

A novel approach has been constructed for the synthesis of two types of 2-amino-4-coumarinyl-5-arylpyrroles (ACAPs, 5 and 6) through a cascade reaction and a metal-free catalyzed aerobic oxidation reaction of arylglyoxal monohydrates 1, 1,1-enediamines (EDAMs) 2 and 3, and 4-hydroxy-2H-chromen-2-ones 4 via multicomponent reactions to produce the target compounds with good to excellent yields. Specifically, hydroxyl-substituted 2-amino-4-coumarinyl-5-arylpyrroles, that is, 2-amino-4-coumarinyl-5-aryl-6-hydroxylpyrroles (ACAHPs) 6, were obtained by metal-free aerobic oxidation in 1,4-dioxane at simple reflux for approximately 10 h. As a result, ACAHPs 6 have been produced without metal catalysts or traditional oxidizing agents. This method represents a route to obtain the novel ACAPs in an environmentally friendly, concise, rapid, and practical manner with potential biological activity of the product.

Three-Component Cascade Reaction of 1,1-Enediamines, N,N-Dimethylformamide Dimethyl Acetal, and 1,3-Dicarbonyl Compounds: Selective Synthesis of Diverse 2-Aminopyridine Derivatives.

A novel approach has been developed for the synthesis of three kinds of highly functionalized 2-aminopyridine derivatives (APDs) through a three-component reaction of 1,1-enediamines (EDAMs) 1, N,N-dimethylformamide dimethyl acetal (DMF-DMA) 2, and 1,3-dicarbonyl compounds 3-5 via a base-promoted cascade reaction, producing the desired products in good to excellent yields. This method represents a route to obtain a novel class of APDs in a concise, rapid, and practical manner. This approach is particularly attractive because of the following features: low cost, mild temperature, atom economy, high yields, and potential biological activity of the product.

N-doped graphene/CoFe2O4 catalysts for the selective catalytic reduction of NO x by NH3.

In this paper, CoFe2O4/graphene catalysts and N-doped graphene/CoFe2O4 (CoFe2O4/graphene-N) catalysts were prepared using the hydrothermal crystallization method for the selective catalytic reduction of NO x by NH3. The results of the test showed that CoFe2O4/graphene catalysts exhibited the best denitrification activity when the loading was at 4% and the conversion rate of NO x reached 99% at 250-300 °C. CoFe2O4/graphene-N catalysts presented a better denitrification activity at low temperature than CoFe2O4/graphene catalysts, and the conversion rate of NO x reached more than 95% at 200-300 °C. The intrinsic mechanism of CoFe2O4/graphene-N catalysts in promoting SCR activity was preliminarily explored. The physicochemical properties of the samples were characterized using XRD, TEM, N2 adsorption, XPS, NH3-TPD, and H2-TPR. The results indicated that nitrogen doping can improve the dispersion of CoFe2O4, and it also increased the acidic sites and the redox performance conducive to improving the denitrification activity of the catalysts. In addition, CoFe2O4/graphene-N catalysts demonstrated a better resistance to water and sulfur than CoFe2O4/graphene catalysts.

Photocatalytic performance of Ag2S/ZnO/ZnS nanocomposites with high visible light response prepared via microwave-assisted hydrothermal two-step method.

A series of different ratios of Ag2S/ZnO/ZnS nanocomposites with visible light response were prepared by a microwave-assisted hydrothermal two-step method, whose composition, crystalline structure, morphology and surface physicochemical properties were well-characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis/DRS), photoluminescence spectrum (PL), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and N2 adsorption-desorption measurements. Results showed that as-composites mainly consisted of ZnS crystal phase, whose grain size increased obviously compared with non Ag2S samples. At the same time, due to the introduction of narrow band gap Ag2S, the synthesized composite can effectively increase the visible optical absorption of ZnO/ZnS composites. Among them, 1% Ag2S/ZnO/ZnS showed a mixed structure of nano-line and nano-particle, of which BET value increased significantly, and the morphology was more excellent. Photocatalytic activities of a series of Ag2S/ZnO/ZnS composites under different light sources were studied using methyl orange as a model molecule, and 1% Ag2S/ZnO/ZnS was taken as the best one. Meanwhile, 1% Ag2S/ZnO/ZnS also showed a good degradation effect on other dyes with different structures, and its degradation efficiency did not change significantly after three cycles, showing certain stability. In addition, composites with Ag2S loading of 1% possessed the highest hydrogen production ability of photolysis water, indicating that the introduction of Ag2S had significantly enhanced the catalytic performance.

Recent Advancements in Graphene-Based Supports of Metal Complexes/Oxides for Epoxidation of Alkenes.

In the past decade, there has been great progress in the preparation and catalytic applications of graphene-supported metal complexes/oxide catalysts. Graphene-based materials have attracted tremendous research interest owing to special physicochemical properties, for example, unique two-dimensional structure, high theoretical specific surface area, high electrical conductivity, and outstanding acid-base resistance properties. Graphene-supported metal complexes/oxides have been extensively investigated, and exhibit good catalytic activity and stability in water splitting (H2 generation or oxygen evolution), oxidation/epoxidation of alkenes, C-C bond formation, and so forth. Herein, recent developments in graphene-supported metal complexes/oxides for the catalytic epoxidation of different alkenes are summarized. Site isolation and synergistic interactions between metal complexes/oxides and graphene are the two key roles for enhancing the catalytic activity, whereas the hydrophobicity of the support can efficiently improve epoxide selectivity. In addition, the possible mechanisms of catalytic epoxidation are summarized. This review provides a feasible scheme for the potential application of graphene-based materials and guidance for the rational design of heterogeneous catalysts for catalytic applications.

Site-Selective Reaction of Enaminones and Enamine Esters for the Synthesis of Novel Diverse Morphan Derivatives.

An efficient and concise protocol was developed for the synthesis of diverse morphan derivatives 5-7 by the Michael and aza-Michael reaction of different types of quinone monoketals 1 or quinone imine ketals 2 with enaminones or enamine esters 3 promoted by 1,8-diazabicyclo[5.4.0]undec-7-ene in acetone at reflux. Notably, when cyclic enaminone 4 was used as a substrate in the aza-Michael and 1,2-addition reactions with quinone monoketals 1, they gave another novel morphan 8. This method is suitable for parallel synthesis of bridged ring compounds. As a result, highly diverse morphan derivatives were easily and efficiently prepared by the Michael/aza-Michael or aza-Michael/1,2-addition reactions.

Design and synthesis of multistructured three-dimensionally ordered macroporous composite bismuth oxide/zirconia: Photocatalytic degradation and hydrogen production.

Two types of three-dimensionally ordered macroporous (3DOM) Bi2O3/ZrO2 composites were prepared by the sol-gel method combined with the decompression filling method using polystyrene (PS) microspheres and EO20PO70EO20 (P123) as the templates. The crystal structure, morphology, and surface physicochemical properties of Bi2O3/ZrO2 composites were well characterized by X-ray diffraction, UV-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and N2 adsorption-desorption measurements. The results show that 3DOM Bi2O3/ZrO2 composites possessed mixed crystal phases including the monoclinic bismuth oxide and mixed zirconia phases, and moreover exhibited a regular arrangement and pure tetragonal (or hexagonal) macroporous structure. Moreover, compared to Bi2O3/ZrO2, the specific surface areas of 3DOM Bi2O3/ZrO2 composites were ca. 2.7-2.8 times. In addition, the properties of 3DOM Bi2O3/ZrO2 composites with the tetragonal "fishing net" and hexagonal "honeycomb" structure were compared, and the relationship between the structure and activity of 3DOM Bi2O3/ZrO2 composites was determined. The results show that in the UV photocatalytic degradation of pollutants and splitting of water into hydrogen using 3DOM Bi2O3/ZrO2 composite, the tetragonal "fishing net" structure exhibited better activity than the hexagonal "honeycomb" structure. This can be attributed to different photocatalytic properties of the composites with different structures (tetragonal "fishing net" and hexagonal "honeycomb" structures).

[Preparation and optimization of polymer-based monolithic stationary phase for high performance liquid chromatography].

Unstirred in-situ polymerization was employed to directly produce glycidyl methacrylate-ethylene dimethacrylate copolymer (poly(GMA-co-EDMA)) monoliths. Mercury intrusion method was adopted to measure some parameters of the monoliths, such as pore size distribution, porosity and specific surface area. Effects of key variables such as composition of pore-forming solvent mixture, temperature and content of cross-linking reagent, divinyl monomer on porous structure of monoliths were studied. The optimization of preparation conditions was achieved. Homogeneous micro porous structure was observed in the monoliths by scanning electron microscope. The effect of flow rate on back pressure was investigated, and good permeability of the monolithic stationary phase was obtained. The monolithic column was also used for the separation of goat serum and five oligonucleotides, and the results proved that the monolithic column is suitable for the separation of biopolymers.

Preparation and evaluation of a large-volume radial flow monolithic column.

In this study, a 38 mL monolith with homogeneous porous structure was produced by a single polymerization from glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) in the presence of porogens and an initiator. The uniform temperature distribution within the reaction system was achieved by adding reactant mixture continuously and enhancing the heat transfer ability of the polymerization system. Homogeneous porous structure in the monolith was proved by SEM and the pore size distribution profiles measured by mercury intrusion porosimetry. Experimental results from proteins separation indicated that the dynamic capacity and resolution of radial flow monolithic column were independent of flow rates. Furthermore, the pressure drop on the column was linearly dependent on the flow rate and did not exceed 1.7 MPa even at a flow rate of 50 mL/min, which proved that the prepared monolith could be used in the quick separation and preparation of biopolymers.