Construction of Fe3O4@Au catalysts via the surface functional group effect of ferric oxide for efficient electrocatalytic nitrite reduction.

Surface modification is one of the effective strategies to control the morphology and electrocatalytic performance of noble metal/transition metal oxide matrix composite catalysts. In this work, we successfully introduced modification groups such as -NH2, -COOH, and -SH on the surface of Fe3O4 using the hydrothermal method. It was found that when the modification group -COOH was introduced, the regular spherical morphology of Fe3O4 was still maintained in Fe3O4-COOH, while Fe3O4-COOH had a relatively smaller spherical particle size (≈155.9 nm). Due to its smaller particle size, Fe3O4-COOH has a larger active area than Fe3O4, exposing more active sites. The abundant active sites in Fe3O4-COOH provide more nucleation and growth sites for Au particles, which is beneficial for the recombination between Fe3O4-COOH and Au. In addition, the experimental results of exploring the effect of Au precursor dosage on the synthesis of the Fe3O4-COOH@Au structure and performance show that the synthesized Fe3O4-COOH@Au1.0 catalyst has higher electrocatalytic activity. Due to the larger electrochemically active surface area of the Fe3O4-COOH@Au1.0 catalyst compared to those of Fe3O4-COOH@Au0.5 and Fe3O4-COOH@Au1.5 catalysts, the adsorption and activation of NO2- reactants were accelerated, thereby improving the electrocatalytic performance. Therefore, owing to the morphological and structural characteristics of Fe3O4-COOH combined with the high activity of Au nanoparticles, the synthesized Fe3O4-COOH@Au exhibits effective electrocatalytic activity in the electrocatalytic NO2-RR synthesis of ammonia. At a voltage of -0.8 V (vs. RHE), the ammonia yield reached 2092.8 µg h-1 mgcat-1 and Faraday efficiency reached 81.2%. The findings of this work will enrich our understanding of the construction of efficient Fe3O4@Au catalysts based on surface functionalization and help to design efficient electrocatalytic NO2-RR catalysts for practical applications.

Surface Structure Reformulation from CuO to Cu/Cu(OH)2 for Highly Efficient Nitrate Reduction to Ammonia.

Electrochemical conversion of nitrate (NO3 -) to ammonia (NH3) is a potential way to produce green NH3 and remediate the nitrogen cycle. In this paper, an efficient catalyst of spherical CuO made by stacking small particles with oxygen-rich vacancies is reported. The NH3 yield and Faraday efficiency are 15.53 mg h-1 mgcat -1 and 90.69%, respectively, in a neutral electrolyte at a voltage of -0.80 V (vs. reversible hydrogen electrode). The high activity of the electrodes results from changes in the phase and structure during electrochemical reduction. Structurally, there is a shift from a spherical structure with dense accumulation of small particles to a layered network structure with uniform distribution of small particles stacked on top of each other, thus exposing more active sites. Furthermore, in terms of phase, the electrode transitions from CuO to Cu/Cu(OH)2. Density functional theory calculations showed that Cu(OH)2 formation enhances NO3- adsorption. Meanwhile, the Cu(OH)2 can inhibit the competing hydrogen evolution reaction, while the formation of Cu (111) crystal surfaces facilitates the hydrogenation reaction. The synergistic effect between the two promotes the NO3- to NH3. Therefore, this study provides a new idea and direction for Cu-based oxides in electrocatalytic NH3 production.

Dry eye disease caused by viral infection: Past, present and future.

Following viral infection, the innate immune system senses viral products, such as viral nucleic acids, to activate innate defence pathways, leading to inflammation and apoptosis, control of cell proliferation, and consequently, threat to the whole body. The ocular surface is exposed to the external environment and extremely vulnerable to viral infection. Several studies have revealed that viral infection can induce inflammation of the ocular surface and reduce tear secretion of the lacrimal gland (LG), consequently triggering ocular morphological and functional changes and resulting in dry eye disease (DED). Understanding the mechanisms of DED caused by viral infection and its potential therapeutic strategies are crucial for clinical interventional advances in DED. This review summarizes the roles of viral infection in the pathogenesis of DED, applicable diagnostic and therapeutic strategies, and potential regions of future studies.

RNF213 gene silencing upregulates transforming growth factor ß1 expression in bone marrow-derived mesenchymal stem cells and is involved in the onset of Moyamoya disease.

Moyamoya disease (MMD) is a chronic and progressive cerebrovascular occlusion disease, the precise etiology of which is poorly understood. Ring finger protein 213 (RNF213) has been previously identified as a susceptibility gene that serves an important role in angiogenesis, where it has been shown to be closely associated with the onset of MMD. Patients with MMD exhibit increased expression levels of various pro-inflammatory molecules and angiogenic factors. Under certain conditions, bone marrow mesenchymal stem cells (BMSCs) have the ability to differentiate to form neuron-like and microglia-like cells. In the present study, a total of 40 MMD patients and 40 healthy individuals were enrolled. ELISA assays revealed that the expression of serum vascular endothelial growth factor (VEGF) and transforming growth factor ß1 (TGF-ß1) were higher than that in healthy controls. Furthermore, rat BMSCs (rBMSCs) were isolated and cultured using the whole bone marrow adherence method, which were then phenotyped using flow cytometry. Osteogenic and adipogenic differentiation were determined by using Alizarin red and oil red O staining, respectively. RNF213 was knocked-down using a lentivirus-mediated short hairpin RNA system in passage three rBMSCs, and successful transfection of the RNF213 was confirmed by RT-qPCR and fluorescence imaging. The expression levels of VEGF and TGF-ß1 in these rBMSCs were measured on days 7 and 14, respectively. The results demonstrated that RNF213 knockdown upregulated TGF-ß1 at both protein and mRNA levels, but did not exert any effect on VEGF gene expression. In conclusion, these findings suggested that that RNF213 knockdown may contribute to aberrant TGF-ß1 expression via a pathway that remains to be unidentified, indicating that quantitative changes in RNF213 gene expression may serve an important role in the pathogenesis of MMD.

Analysis of Cyclooxygenase 2, Programmed Cell Death Ligand 1, and Arginase 1 Expression in Human Pituitary Adenoma.

BACKGROUND: Cyclooxygenase 2 (COX-2) is a key enzyme in the synthesis of prostaglandins. Recent studies have shown that overexpression of COX-2 can reduce the antitumor effect of the immune system by inhibiting the proliferation of B and T lymphocytes. Programmed cell death ligand 1 (PD-L1) was the first functionally characterized ligand of programmed cell death protein 1. It plays an important role in maintaining peripheral and central immune tolerance by combining with programmed cell death protein 1. Arginase 1 (ARG1) can process L-arginine in the local microenvironment and affect the function of T cells, resulting in immune escape. In this study, COX-2, PD-L1, and ARG1 expression in human pituitary adenoma (PA) and their relationship were investigated, which provided an initial theoretic basis for further study of the immune escape mechanism in PA in cellular and animal experiments. METHODS: The protein expression of COX-2, PD-L1, and ARG1 in 55 PA samples was detected by immunohistochemistry, with 10 normal brain tissues as the control group. The location of COX-2, PD-L1, and ARG1 in PA cells was studied by double immunofluorescence colocalization. The results of immunohistochemistry were further verified by Western blot. RESULTS: The expression of COX-2, PD-L1, and ARG1 in PA was significantly higher than that in normal brain tissue. In functional PA (FPA) and nonfunctional PA (NFPA), there was no significant difference in the expression of COX-2 and PD-L1, whereas ARG1 was higher in NFPA. Moreover, the protein expression level of COX-2 was positively correlated with that of PD-L1 and ARG1, and the expression of PD-L1 was positively correlated with that of ARG1. Immunofluorescence confocal imaging showed that COX-2, PD-L1, and ARG1 were all expressed in the cytoplasm of PA cells, and the physical positions of COX-2, PD-L1, and ARG1 were partially coincident. CONCLUSIONS: These findings indicate that overexpression of COX-2, PD-L1, and ARG1 may be involved in the pathogenesis of PA. ARG1 plays a more important role in the development of NFPA. By upregulating the expression of PD-L1, COX-2 may promote the expression of ARG1, forming the COX-2/PD-L1/ARG1 signal pathway in promoting the occurrence and development of PA. Perhaps further study of the pathogenesis of PA can start with the mechanism of immune escape.

Determination of isopropyl-9H-thioxanthen-9-one in packaged beverages by solid-phase extraction clean-up and liquid chromatography with tandem mass spectrometry detection.

A simple method was developed and validated for the trace determination of 2-isopropylthioxanthone (ITX) in packaged drinks. Samples were extracted from the food matrix using acetonitrile:water (60:40, v/v), and further subjected to clean-up and preconcentration using solid-phase extraction prior to analysis by liquid chromatography-tandem mass spectrometry using multiple reaction monitoring (MRM) mode. The use of 2-isopropyl-[(2)H7]thioxanthen-9-one was incorporated into the method as an internal standard. Excellent 3-day interday precision data (RSD 0.72%, n=10), and intraday precision data (RSD 0.52%, n=10) were obtained on a 0.10 microg/L standard solution. Spiked samples (n=8) were used to gauge the accuracy of the method at the concentration levels of 2.5, 100, and 500 microg/kg in food; recoveries ranged from 97.0 to 103.0%. These excellent validation data suggest the exciting possibility of using this method for the determination of low levels of ITX migrating from printed food packaging materials into beverages with a method quantitation limit of 0.50 microg/kg. For the first time, analysis on a range of milk, juice, tea and yoghurt drinks, as well as their respective food packaging materials were performed for comparative studies on their ITX content.

Single laboratory validation of a method for the determination of Bisphenol A, Bisphenol A diglycidyl ether and its derivatives in canned foods by reversed-phase liquid chromatography.

A method was developed and validated for the simultaneous determination of Bisphenol A (BPA), Bisphenol A diglycidyl ether (BADGE), BADGE-H2O, BADGE-2H2O, BADGE-H2O-HCl, BADGE-HCl, and BADGE-2HCl in canned food using reversed phase high-performance liquid chromatography (HPLC) with fluorescence detection; chromatographic separation of all seven analytes was achieved (Rs > or = 1.08) using HPLC gradient elution technique. Acetonitrile was used to extract the analytes from the food matrix before subjecting the samples to liquid-liquid extraction, solid-phase extraction for further clean-up and preconcentration prior to HPLC analysis. Excellent inter-day precision data (n = 10) and intra-day precision data (n = 5) were obtained on a 200 microg/kg spiked sample. The RSD ranged from 0.20% to 2.96% for the inter-day precision tests, and 0.04% to 2.82% for the intra-day precision tests. Accuracy was measured at three concentration levels: 200, 1000, and 2000 microg/kg; recoveries ranged from 86.07% to 114.06%. The excellent validation data suggests that this method can be applied on canned foods for the determination of migration of BPA, BADGE and its derivatives from can coatings into food.