Facet impact of CeO2@C 2D core-shell structure on electrochemical reaction kinetic factor and efficient detection of nitrite.

Fine-tuning the surface structure of transition metal oxides at the atomic level is a promising way to improve the catalytic properties of materials. However, the influence of crystal surface structure on electrode reaction kinetics is still limited. In this study, we propose an in-situ synthesis strategy to obtain two-dimensional carbon/cerium oxide core-shell nanosheets by thermal decomposition of Ce-MOF nanosheets grown on the surface of carbon nanostructures, and fine-tuning the surface structure by introducing oxygen vacancies through defect engineering during the oxide nucleation process is conducted to obtain controllable exposed {111} and {110} surface CeO2@C composites. Both experiments and theoretical calculations show that the {110} -dominated nanocomplex (CeO2@C-350S) has better kinetic behavior and catalytic activity due to its abundant surface defects, which is manifested in higher active surface area, richer carrier concentration, and better promotion of diffusion and adsorption. In addition, CeO2@C-350S electrode has an extremely wide linear range and good stability in the electrochemical detection of nitrite. After 1000 times of the accelerated cycle experiments, CeO2@C-350S electrode still maintains 79.3 % of its initial current response, and recovers to 87.3 % after 10 min of stopping the test. The electrode stability is excellent, which is attributed to the clever carbon shell structure of the material. This synthesis strategy can be extended to other carbon-based oxide composite catalysts to improve the electrocatalytic performance and overall stability by adjusting the surface structure.

The Influence of TiO2 Nanoparticles Morphologies on the Performance of Lithium-Ion Batteries.

Anode materials based on the TiO2 nanoparticles of different morphologies were prepared using the hydrothermal method and characterized by various techniques, such as X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and N2 absorption. The TiO2 nanoparticles prepared were used as anode materials for lithium-ion batteries (LIBs), and their electrochemical properties were tested using discharging/charging measurements. The results showed that the initial morphology of the nanoparticles plays a minor role in battery performance after the first few cycles and that better capacity was achieved for TiO2 nanobelt morphology. The sharp drop in the specific capacity of LIB during their first cycles is examined by considering changes in the morphology of TiO2 particles and their porosity properties in terms of size and connectivity. The performance of TiO2 anode materials has also been assessed by considering their phase.

Inhibition of hyaluronic acid degradation pathway suppresses glioma progression by inducing apoptosis and cell cycle arrest.

BACKGROUND: Abnormal hyaluronic acid (HA) metabolism is a major factor in tumor progression, and the metabolic regulation of HA mainly includes HA biosynthesis and catabolism. In glioma, abnormal HA biosynthesis is intimately involved in glioma malignant biological properties and the formation of immunosuppressive microenvironment; however, the role of abnormal HA catabolism in glioma remains unclear. METHODS: HA catabolism is dependent on hyaluronidase. In TCGA and GEPIA databases, we found that among the 6 human hyaluronidases (HYAL1, HYAL2, HYAL3, HYAL4, HYALP1, SPAM1), only HYAL2 expression was highest in glioma. Next, TCGA and CGGA database were further used to explore the correlation of HYAL2 expression with glioma prognosis. Then, the mRNA expression and protein level of HYAL2 was determined by qRT-PCR, Western blot and Immunohistochemical staining in glioma cells and glioma tissues, respectively. The MTT, EdU and Colony formation assay were used to measure the effect of HYAL2 knockdown on glioma. The GSEA enrichment analysis was performed to explore the potential pathway regulated by HYAL2 in glioma, in addition, the HYAL2-regulated signaling pathways were detected by flow cytometry and Western blot. Finally, small molecule compounds targeting HYAL2 in glioma were screened by Cmap analysis. RESULTS: In the present study, we confirmed that Hyaluronidase 2 (HYAL2) is abnormally overexpressed in glioma. Moreover, we found that HYAL2 overexpression is associated with multiple glioma clinical traits and acts as a key indicator for glioma prognosis. Targeting HYAL2 could inhibit glioma progression by inducing glioma cell apoptosis and cell cycle arrest. CONCLUSION: Collectively, these observations suggest that HYAL2 overexpression could promote glioma progression. Thus, treatments that disrupt HA catabolism by altering HYAL2 expression may serve as effective strategies for glioma treatment.

Effect of Withdrawal Rate on Solidification Microstructures of DD9 Single Crystal Turbine Blade.

Single crystal superalloys are widely used in the manufacturing of turbine blades for aero-engines due to their superior performance at high temperatures. The directional solidification process is a key technology for producing single crystal turbine blades with excellent properties. In the directional solidification process, withdrawal rate is one of the critical parameters for microstructure formation and will ultimately determine the blade's properties. In this paper, the as-cast microstructures in the typical sections of a DD9 single crystal (SX) superalloy turbine blade were investigated with 3 mm/min and 5 mm/min withdrawal rates during the directional solidification process. With increased withdrawal rate, the dendrite morphologies tended to become more refined, and the secondary dendritic arms tended to be highly developed. The dendrite in the blade aerofoil section was more refined than that in the tenon section, given the same withdrawal rate. Additionally, with increasing withdrawal rates, the size and dispersity of the γ' precipitates in the inter-dendritic (ID) regions and dendritic core (DC) tended to decrease; furthermore, the size distributions of the γ' precipitates followed a normal distribution law. Compared with the ID regions, an almost 62% reduction in the average γ' sizes was measured in the DC. Meanwhile, given the same withdrawal rate, at the blade's leading edge closest to the heater, the γ' sizes in the aerofoil section (AS) were more refined than those in the tenon section (TS). As compared with the decreasing cross-sectional areas, the increased withdrawal rates clearly brought down the γ' sizes. The sizes of the γ-γ' eutectics decreased with increasing withdrawal rates, with the γ-γ' eutectics showing both lamellar and rosette shapes.

Targeting copper death genotyping associated gene RARRES2 suppresses glioblastoma progression and macrophages infiltration.

BACKGROUND: Copper homeostasis is associated with malignant biological behavior in various tumors. The excessive accumulation of copper can induce tumor death, which is named cuproptosis, and it is also closely related to tumor progression and the formation of the immune microenvironment. However, the associations of cuproptosis with glioblastoma (GBM) prognosis and microenvironment construction are poorly understood. METHOD: First, TCGA and GEO (GSE83300, GSE74187) merged datasets were used to analyze the association of cuproptosis-related genes (CRGs) with GBM. Then, we performed cluster analysis of CRGs in GBM from the GEO (GSE83300, GSE74187) and TCGA merged datasets. Subsequently, the prognostic risk model was constructed by least absolute shrinkage and selection operator (LASSO) according to gene expression features in CRG clusters. Next, we performed a series of in-depth analyses, including tumor mutational burden (TMB) analysis, cluster analysis, and GBM IDH status prediction. Finally, RARRES2 was identified as a target gene for GBM treatment, especially IDH wild-type GBM. In addition, we further analyzed the correlation of CRG clusters and RARRES2 expression with the GBM immune microenvironment by ESTIMATE and CIBERSORT analyses. In vitro experiments were conducted to demonstrate that targeting RARRES2 inhibits glioblastoma progression and macrophage infiltration, particularly IDH wild-type GBM. RESULTS: In the present study, we demonstrated that the CRG cluster was closely related to GBM prognosis and immune cell infiltration. Moreover, the prognostic risk model constructed with the three genes (MMP19, G0S2, RARRES2) associated with the CRG clusters could well evaluate the prognosis and immune cell infiltration in GBM. Subsequently, after further analyzing the tumor mutational burden (TMB) in GBM, we confirmed that RARRES2 in the prognostic risk model could be used as a crucial gene signature to predict the prognosis, immune cell infiltration and IDH status of GBM patients. CONCLUSION: This study fully revealed the potential clinical impact of CRGs on GBM prognosis and the microenvironment, and determined the effect of the crucial gene (RARRES2) on the prognosis and tumor microenvironment construction of GBM, meanwhile, our study also revealed over-expressed RARRES2 is related to the IDH satus of GBM, which provides a novel strategy for the treatment of GBM, particularly IDH wild-type GBM.

2D metal-organic framework-based materials for electrocatalytic, photocatalytic and thermocatalytic applications.

Ultrathin two-dimensional metal-organic frameworks (2D MOFs) have recently attracted extensive interest in various catalytic fields (e.g., electrocatalysis, photocatalysis, thermocatalysis) due to their ultrathin thickness, large surface area, abundant accessible unsaturated active sites and tunable surface properties. Besides tuning the intrinsic properties of pristine 2D MOFs by changing the metal nodes and organic ligands, one of the hot research trends is to develop 2D MOF hybrids and 2D MOF-derived materials with higher stability and conductivity in order to further increase their activity and durability. Here, the synthesis of 2D MOF nanosheets is briefly summarized and discussed. More attention is focused on summaries and discussions about the applications of these 2D MOFs, their hybrids and their derived materials as electrocatalysts, photocatalysts and thermocatalysts. The superior properties and catalytic performance of these 2D MOF-based catalysts compared to their 3D MOF counterparts in electrocatalysis, photocatalysis and thermocatalysis are highlighted. The enhanced activities of 2D MOFs, their hybrids and derivatives come from abundant accessible active sites, a high density of unsaturated metal nodes, ultrathin thickness, and tunable microenvironments around the MOFs. Views regarding current and future challenges in the field, and new advances in science and technology to meet these challenges, are also presented. Finally, conclusions and outlooks in this field are provided.

An Improved High-Throughput Data Processing Based on Combinatorial Materials Chip Approach for Rapid Construction of Fe-Cr-Ni Composition-Phase Map.

The combinatorial materials chip approach is vastly superior to the conventional one that characterizes one sample at a time in the efficiency of composition-phase map construction. However, the resolution of its high-throughput characterization and the correct rate of automated composition-phase mapping are often affected by inherent experimental limitations and imperfect automated analyses, respectively. Therefore, effective data preprocessing and refined automated analysis methods are required to automatically process huge amounts of experiment data to score a higher correct rate. In this work, the pixel-by-pixel structural and compositional characterization of the Fe-Cr-Ni combinatorial materials chip annealed at 750 °C was performed by microbeam X-ray at a synchrotron light source and by electron probe microanalysis, respectively. The severe baseline drift and system noise in the X-ray diffraction patterns were successfully eliminated by the three-step automated preprocessing (baseline drift removal, noise elimination, and baseline correction) proposed, which was beneficial to the subsequent quantitative analysis of the patterns. Through the injection of human experience, hierarchy clustering analyses, based on three dissimilarity measures (the cosine, Pearson correlation coefficient, and Jenson-Shannon divergence), were further accelerated by the simplified vectorization of the preprocessed X-ray diffraction patterns. As a result, a correct rate of 91.15% was reached for the whole map built automatically in comparison with the one constructed manually, which confirmed that the present data processing could assist humans to improve and expedite the processing of X-ray diffraction patterns and was feasible for composition-phase mapping. The constructed maps were generally consistent with the corresponding isothermal section of the Fe-Cr-Ni ternary alloy system in the ASM Alloy Phase Diagram Database except the inexistence of the σ phase under insufficient annealing.

A facile one-pot hydrothermal method to produce SnS2/reduced graphene oxide with flake-on-sheet structures and their application in the removal of dyes from aqueous solution.

In this article, we report a novel one-pot synthesis of SnS2/reduced graphene oxide (rGO) flake-on-sheet nanocomposites via in situ reduction of graphene oxide (GO) by Sn(2+) under hydrothermal conditions. The morphology and structure of the obtained product were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction instrument (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The adsorption characteristics of the SnS2/rGO nanocomposites were examined using an organic dye Rhodamine B (RhB) as adsorbate. SnS2/rGO exhibited superior adsorption behavior for RhB. The adsorption kinetics and adsorption isotherm were investigated. The adsorption of RhB by SnS2/rGO was well fitted to the Langmuir isotherm model, and the resultant kinetic data were well described by pseudo-second-order model.

Fabrication of polypyrrole/graphene oxide composite nanosheets and their applications for Cr(VI) removal in aqueous solution.

In this paper, we report on the simple, reliable synthesis of polypyrrole (PPy)/graphene oxide (GO) composite nanosheets by using sacrificial-template polymerization method. Herein, MnO(2) nanoslices were chosen as a sacrificial-template to deposit PPy, which served as the oxidant as well. During the polymerization of pyrrole on surface of GO nanosheets, MnO(2) component was consumed incessantly. As a result, the PPy growing on the surface of GO nanosheets has the morphology just like the MnO(2) nanoslices. This method can provide the fabrication of PPy nanostructures more easily than conventional route due to its independence of removing template, which usually is a complex and tedious experimental process. The as-prepared PPy/GO composite nanosheets exhibited an enhanced properties for Cr(VI) ions removal in aqueous solution based on the synergy effect. The adsorption capacity of the PPy/GO composite nanosheets is about two times as large as that of conventional PPy nanoparticles. We believe that our findings can open a new and effective avenue to improve the adsorption performance in removing heavy metal ions from waste water.

Facile synthesis of highly dispersed palladium/polypyrrole nanocapsules for catalytic reduction of p-nitrophenol.

In this study, a facile one-step redox polymerization method for the preparation of highly dispersed palladium (Pd)/polypyrrole (PPy) nanocapsules has been demonstrated. During the polymerizaion process, the formation of RB-PdCl(4)(2-) complex via an electrostatic interaction plays a key role for the preparation of Pd/PPy composite nanocapsules. The well-dispersed Pd nanocrystals with small sizes of 2-4 nm embedded in PPy nanocapsules exhibited a good catalytic activity during the catalytic reduction of p-nitrophenol into p-aminophenol by NaBH(4) in aqueous solution. The kinetic apparent rate constant (k(app)) was about 8.87×10(-3) s(-1). Moreover, the as-prepared Pd/PPy composite nanocapsules exhibited a good reusability, which could be repeatedly used for the reduction of p-nitrophenol with a high catalytic activity for at least 10 successive cycles.

Preparation of bamboo-like PPy nanotubes and their application for removal of Cr(VI) ions in aqueous solution.

A reactive-template vapor phase polymerization method for the preparation of bamboo-like polypyrrole (PPy) nanotubes has been successfully demonstrated in this paper. Herein, electrospun V(2)O(5) nanofibers were chosen as templates to deposit PPy, which served as the oxidants as well. This method can provide the fabrication of PPy nanostructures more easily than conventional routes due to its independence of removing template, which is usually a complex and tedious experimental process. The application of bamboo-like PPy nanotubes for Cr(VI) ions removal in aqueous solution has been explored. The resulting bamboo-like PPy nanotubes exhibited much higher adsorption performance than traditional PPy nanoparticles.

Fabrication of ternary CNT/PPy/KxMnO2 composite nanowires for electrocatalytic applications.

CNT/PPy/K(x)MnO(2), a novel ternary core-shell nanowires, was successfully prepared by a two-step self-assembly method and utilized as an electrocatalyst for the oxidation of hydrogen peroxide. The as-synthesized products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and Fourier-transform infrared spectra (FTIR) measurements. The results exhibited that the K(x)MnO(2) nanosheets were grown on the surface of CNT/PPy core-shell nanotubes. The planes of the K(x)MnO(2) nanosheets were more or less perpendicular to the CNT/PPy nanotubes. Cyclic voltammetry (CV) results demonstrated that the CNT/PPy/K(x)MnO(2) composite nanowires, as a nonenzyme catalyst, performed well with regards to the oxidation of hydrogen peroxide in 0.1M phosphate buffer solution (pH 7.0). The composite had a fast response with a linear range of 5.0 µM to 9.7 mM and a relatively low detection limit of 2.4 µM (S/N=3). The sensitivity of the sensor for H(2)O(2) was 114.6 µA mM(-1)cm(-2). These excellent properties might be due to the large surface area of the composite nanowires and the quick electron transfer promoted by the combination of CNT and PPy.

Controllable fabrication of porous free-standing polypyrrole films via a gas phase polymerization.

A facile gas phase polymerization method has been proposed in this work to fabricate porous free-standing polypyrrole (PPy) films. In the presence of pyrrole vapor, the films are obtained in the gas/water interface spontaneously through the interface polymerization with the oxidant of FeCl(3) in the water. Both the thickness of the film and the size of the pores could be controlled by adjusting the concentrations of the oxidant and the reaction time. The as-prepared PPy films exhibited a superhydrophilic behavior due to its composition and porous structures. We have demonstrated a possible formation mechanism for the porous free-standing PPy films. This gas phase polymerization is shown to be readily scalable to prepare large area of PPy films.