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A high voltage current transformer of the inverted type is a commonly used measurement equipment in power grids. The thermal behaviour of the current transformer has a significant impact on its operating conditions and is directly related to its service life. The study presents a three‐dimensional simulation model of a 220 kV inverted‐type oil‐immersed current transformer, and the fluid and temperature field are analysed by the finite volume method. The simulation results show that the hot‐spot temperature under the rated load of the calculation model introduced in the study is 61.5°C, and located at the upper part of the core and the secondary winding. An experiment setup was designed to measure the temperature distribution inside a LVB‐220W3‐type current transformer. The temperature data measured under the rated load indicate that the simulation results agree well with the experimental results.

Background: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation that is not fully reversible. Pulmonary vascular remodeling is the main pathological feature of COPD. Vascular endothelial growth factor (VEGF), the key regulator of angiogenesis, mediates activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway, which regulates the proliferation and migration of vascular endothelial cells and plays important roles in pulmonary angiogenesis and remodeling in COPD. Here, the efficacy of electroacupuncture (EA) with respect to regulation of microvascular remodeling induced by VEGF/PI3K/Akt was evaluated in a rat model of COPD. Methods: Rats were randomly assigned to blank, COPD model, EA and sham acupuncture (SA) groups. Rats in the EA group received EA at GV14, BL13 and BL23 three times per week, while those in the SA group, as a control, received shallow and minimal electrostimulation at sites 5–10 mm away from the traditional acupuncture point locations. After 2, 4 and 8 weeks of treatment, the optimal treatment duration was determined according to the results of lung function, lung pathology and inflammatory factor levels. Then, microvessel density, protein levels and mRNA expression of selected VEGF/PI3K/Akt pathway intermediates were determined by immunofluorescence, immunohistochemistry and Western blot analysis, and mRNA qRT-PCR, respectively. Results: EA improved lung function and lung tissue histopathology, with the best effect after 8 weeks of treatment, as noted by reduced density of lung microvessels and expression of angiogenesis-related factors (VEGF and endothelin (ET)-1). EA-treated COPD rats exhibited reduced VEGF, VEGF receptor 2 (VEGFR2), ET-1 mRNA and VEGF, VEGFR2, phosphorylated (p)-VEGFR2, PI3K, Akt, p-Akt, mammalian target of rapamycin (mTOR), and p-mTOR at the protein level in comparison with untreated and SA-treated COPD model rats. Conclusion: EA had beneficial effects on COPD in this animal model including reduced pulmonary vascular remodeling via mechanisms possibly related to the VEGF/PI3K/Akt pathway.

The embryo in maize has a critical role in controlling kernel nutrition components and grain yield. We measured five embryo weight and size traits, six kernel weight and size traits, and five embryo-to-kernel ratio traits in a nested association mapping (NAM) population of 611 recombinant inbred lines (RILs) derived from four inbred lines including the high-oil, giant-embryo line BY815 as the common parent. Using three statistical methods, we identified 5–22 quantitative trait loci (QTL) for each trait, explaining 4.7%–46.7% of the phenotypic variation. The genetic architecture of maize embryo size and its related traits appeared to be dominated by multiple small-effect loci with little epistasis, and the genetic control underlying embryo size appeared to be distinct from that underlying kernel size. A trait–QTL association network included 205 nodes and 439 edges and revealed 28 key loci associated with at least three traits. Cloned maize genes including ZmUrb2, Emp12 and ZmBAM1d, maize orthologs of known rice genes that control seed size including BG1, XIAO and GS9, and 11 maize orthologs of Arabidopsis EMBRYO-DEFECTIVE (EMB) genes were identified as underlying these key loci. Further, the phenotypic and genetic relationships between embryo size and kernel size were evaluated, and genetic patterns for identified loci that control embryo size and its related traits were proposed. Our findings reveal distinct genetic architectures for embryo size, kernel size, and embryo-to-kernel ratio traits and establish a foundation for the improvement of embryo-size-mediated kernel nutrition and grain yield.

In this study, we successfully demonstrate the synthesis of a novel necklace-like Co, Fe, and N co-doped one-dimensional (1D)-assembly of hollow carbon nanoboxes (1D-HCNB-x) and its potential for supercapacitor application.

Synchronous online courses have attracted wide attention during the COVID-19 pandemic. Teachers must have excellent technical skills and a foundation of web knowledge in order to deliver a quality online course. A teacher's information literacy is one important skill against which one can evaluate their professional ability with regard to online instruction. Therefore, this study focuses on selecting teachers from two provinces in China and distributing relevant questionnaires to explore the current situation and training needs of primary and secondary school teacher information literacy from the perspective of professional development. The results show that primary and secondary school teachers have a high level of information consciousness and information ethics, but information knowledge and information ability need to be improved. In addition, there is no significant difference in information literacy among teachers of different gender, age, educational background, and professional title. Technology application and centralized training are the main training contents and formats that teachers look for.

This paper reviewed the properties and relationship of reactive oxygen species and anions in persulfate-based advanced oxidation processes for saline organic wastewater treatment.

There are limited studies on the semantic segmentation of high-resolution polarimetric synthetic aperture radar (PolSAR) images due to the scarcity of training data and the complexity of managing speckle noise. The Gaofen contest has provided open access a high-quality PolSAR semantic segmentation dataset. Taking this opportunity, we propose a multipath residual network (MP-ResNet) architecture for the semantic segmentation of high-resolution PolSAR images. Compared to conventional U-shape encoder-decoder convolutional neural network (CNN) architectures, the MP-ResNet learns semantic context with its parallel multiscale branches, which greatly enlarges its valid receptive fields and improves the embedding of local discriminative features. In addition, MP-ResNet adopts a multilevel feature fusion design in its decoder to effectively exploit the features learned from its different branches. Comparisons with the baseline method of fully connected network (FCN with ResNet34) show that the MP-ResNet has achieved significant accuracy improvements. It also surpasses several state-of-the-art methods in terms of overall accuracy (OA), mF₁ and frequency weighted intersection over union (fwIoU), with only a limited increase of computational costs. This CNN architecture can be used as a baseline method for future studies on the semantic segmentation of PolSAR images. The code is available at: https://github.com/ggsDing/SARSeg.

Objective To evaluate the efficacy and safety of early pulmonary rehabilitation (PR) (ie

Al matrix composites reinforced with ceramic particles show excellent wear resistance and have great potential to replace convectional materials in many fields. In this paper, a high proportion (∼ 60%) of large ZrO2 particles reinforced Al matrix composites were manufactured by a high pressure infiltration method. The tribological behavior of the Al/ZrO2 composite and non-reinforced Al were investigated and compared using a GCr15 ball-on-disc apparatus under dry sliding wear condition. The microstructure, elements distribution and wear track morphology were analyzed to understand their tribological behavior and wear mechanisms. The wear rate of Al is 2.0 × 10−3 mm3 N−1 m−1, while the wear rate of Al/ZrO2 composite is only 0.15 × 10−3 mm3 N−1 m−1. The experimental results showed that Al is a combined wear mechanism of adhesive wear and abrasive wear. It also proved that the high proportion of large ceramic particle reinforced composite is stable under low load wear condition. The ceramic particles were firmly embedded in the Al matrix, and no ejection or removal of the particles was observed. The results showed that the wear mechanism of this composite is mainly three body abrasion in the stable wear stage.

Objective This study aims to determine the mechanism of ISLR on the progression of colon cancer. Methods TCGA database was used to analyze ISLR expression in colon cancer tumor tissues. QRT-PCR and western blotting were used to detect ISLR expression in colon cancer cells. CCK-8, colony formation, EDU, wound healing and transwell assays were used to measure cell viability, proliferation, migration and invasion of colon cancer cells, respectively. The signaling pathway enrichment analysis of ISLR was analyzed on the basis of the KEGG database. The protein expression of genes related to signaling pathway was measured by western blotting. Results Results of TCGA analysis, qRT-PC and western blotting showed that ISLR was upregulated in colon cancer tumor tissues and cells. High level of ISLR was related to low overall survival of patients with colon cancer. ISLR silence significantly inhibited cell viability, proliferation, migration and invasion of colon cancer cells. ISLR overexpression markedly enhanced the cell viability, proliferation, migration and invasion of colon cancer cells. KEGG database analyzed showed that ISLR can activate the EMT signaling pathway. Inhibition of the EMT signaling pathway can suppress the growth, migration, and invasion of colon cancer cells and eliminate the promoted effect of ISLR overexpression on colon cancer progression. Conclusion ISLR promotes the progression of colon cancer by activating the EMT signaling pathway.

As an essential component of power transformers, the detection and diagnosis of incipient partial discharge (PD) activities of bushings are of great significance. A 35‐kV oil‐impregnated paper (OIP) bushing is investigated. The bushing is modelled by coaxial theory and electromagnetic (EM) simulation. As the paths of PD‐induced ultra‐high frequency (UHF) signal propagating in the bushing are OIPs and oil gap, small attenuation during signal propagation is seen. Since OIP is composed of heterogeneous media compared with pure oil, there will be relatively less UHF signal leakage from OIPs, whereas more leakage from the oil gap. This leakage provides the possibility of non‐contact detection outside the bushing by UHF method. PD measurements with UHF method are carried out on the bushing. Then, the minimum energy method is used to extract time‐difference‐of‐arrival (TDOA), and Chan algorithm is adopted to locate points of UHF signal radiation. High accuracy locating with a small error of 15 cm has been achieved. The contactless UHF method‐based tests have demonstrated the effectiveness of online monitoring and locating of bushing PD.

Bushings are essential components in a power transformer where incipient partial discharge (PD) activities and its detection and diagnosis cannot be ignorant. In this paper, an oil-impregnated paper (OIP) bushing is modeled to investigate that the oil gaps between the flange and condenser body in a typical OIP bushing provide a feasible path to trace the electromagnetic signal. As a non-destructive method, UHF (Ultra High Frequency) is proposed to detect 4 typical inside and outside PD defects of 110 kV bushings. To analyze the parameters of different defects, not only phase-resolved partial discharge (PRPD) is presented, but also 16 detailed time-domain and frequency-domain parameters of UHF signal are involved. Then feature extraction and selection are conducted through comparative principal component analysis (PCA) and extremely randomized trees (ET) algorithms. It is revealed that the selected features are representative and ET greatly reduces the amount of data whilst ensuring high accuracy. Fault diagnosis for bushing is finally achieved via support vector machine (SVM) with the selected features. The presented work of bushing PD detection based on UHF sensors provides a complete solution for the bushing diagnosis in potential field application and maintenance.

Mathematics learning is not only about learning knowledge but also about cultivating mathematical thinking and learning how to think about and solve mathematical problems. Unfortunately, the way teachers evaluate students is still based on the student’s academic achievement. Many students learn by rote, which is unsuitable for developing their thinking ability at different levels. With the advent of the era of big data, teaching has become more accurate and convenient. In this paper, we analyze the student’s academic performance at different levels from the point of view of mathematical thinking. We collected the learning achievement of two classes in a middle school in Beijing. We then analyzed the overall thinking of the two classes, and the mathematical thinking level of students at different levels. Based on the analysis results, we put forward some teaching suggestions on improving mathematical thinking to help improve teaching methods and quality and promote students’ mathematical thinking development.

Background. The effective-component compatibility of Bufei Yishen formula III (ECC-BYF III) with 5 ingredients (ginsenoside Rh1, astragaloside, icariin, nobiletin, and paeonol) has been shown to protect against chronic obstructive pulmonary disease (COPD). The present study aimed to observe the effects of ECC-BYF III in a COPD rat model and dissect its potential mechanisms in regulating mucus hypersecretion via the miR-146a-5p/epidermal growth factor receptor (EGFR)/MEK/ERK pathway. Methods. COPD model rats were treated with normal saline, ECC-BYF III, or N-acetylcysteine (NAC). Pulmonary function, lung tissue histology with H & E and AB-PAS staining, expression levels of interleukin (IL)-4, IL-6, IL-1β, MUC5AC, MUC5B, and FOXA2 in lung tissues and the mRNA and proteins involved in the miR-146a-5p/EGFR/MEK/ERK pathway were evaluated. Results. The COPD rats showed a significant decrease in the pulmonary function and serious pathological damage to the lung tissue. ECC-BYF III and NAC significantly improved the ventilation function and small airway pathological damage in the COPD rats. The goblet cells and the expression levels of IL-1β, IL-6, MUC5AC, and MUC5B were increased in the COPD rats and were significantly decreased after ECC-BYF III or NAC intervention. The expression levels of IL-4 and FOXA2 in the COPD rats were markedly decreased and were improved in the ECC-BYF III and NAC groups. ECC-BYF III appeared to have a potent effect in restoring the reduced expression of miR-146a-5p. The increased phosphorylation levels of EGFR, MEK, and ERK1/2 and the protein expression levels of SPDEF in the lungs of COPD rats could be significantly reduced by ECC-BYF III. Conclusions. ECC-BYF III has a significant effect in improving the airway mucus hypersecretion in COPD model rats, as well as a protective effect against limited pulmonary function and injured lung histopathology. The protective effect of ECC-BYF III in reducing airway mucus hypersecretion in COPD may involve the miR-146a-5p/EGFR/MEK/ERK pathway.

The readmission rate following hospitalization for chronic obstructive pulmonary disease (COPD) exacerbations is extremely high and has become a common and challenging clinical problem. This study aimed to systematically summarize COPD readmission rates for acute exacerbations and their underlying risk factors.A comprehensive search was performed using PubMed, Embase, Cochrane Library, and Web of Science, published from database inception to April 2, 2022. Methodological quality was evaluated using the Newcastle-Ottawa Scale (NOS). We used a random-effects model or a fixed-effects model to estimate the pooled COPD readmission rate for acute exacerbations and underlying risk factors.A total of 46 studies were included, of which 24, 7, 17, 7, and 20 summarized the COPD readmission rates for acute exacerbations within 30, 60, 90, 180, and 365 days, respectively. The pooled 30-, 60-, 90-, 180-, and 365-day readmission rates were 11%, 17%, 17%, 30%, and 37%, respectively. The study design type, age stage, WHO region, and length of stay (LOS) were initially considered to be sources of heterogeneity. We also identified potential risk factors for COPD readmission, including male sex, number of hospitalizations in the previous year, LOS, and comorbidities such as heart failure, tumor or cancer, and diabetes, whereas obesity was a protective factor.Patients with COPD had a high readmission rate for acute exacerbations, and potential risk factors were identified. Therefore, we should propose clinical interventions and adjust or targeted the control of avoidable risk factors to prevent and reduce the negative impact of COPD readmission.PROSPERO, identifier CRD42022333581.

Exercise training is the cornerstone component of pulmonary rehabilitation, which results in symptom-reducing, psychosocial, and health economic benefits for chronic obstructive pulmonary disease (COPD) patients. However, the potential mechanisms of its action are poorly understood. This study conducted serum metabolomics using ultra-high performance liquid chromatography-Q-Exactive tandem mass spectrometry to determine the metabolic changes in COPD rats, and the effects of exercise training on improvement in COPD were further investigated. Twelve differential metabolites-which are primarily related to tryptophan metabolism, sphingolipid metabolism, glycerophospholipid metabolism, riboflavin metabolism, pantothenate and CoA biosynthesis, and lysine degradation-were identified in relation to COPD. After the intervention of exercise training, the levels of most metabolites were restored, and the changes in five metabolites were statistically significant, which suggested that exercise training provided effective protection against COPD and might play its role by rebalancing disordered metabolism pathways. This work enhanced our comprehension of the protective mechanism of exercise training on COPD.

After preparing carbon-coated silver (Ag@C) nanoparticles by a one-step hydrothermal synthesis method, the surface of the nanoparticles was modified with chlorodimethyloctylsilane (C8) to generate C8 functionalized Ag@C@C8 nanoparticles. The Ag@C@C8 nanoparticles were then employed as a substrate for surface enhancement Raman scattering (SERS). The high sensitivity, good uniformity, and long stability Raman signals for both probe dyes (rhodamine 6G and crystal violet) and a real sample (malachite green) in water demonstrated good performance of the as-synthesised Ag@C@C8 nanoparticles. SEM images and TEM images indicate the successful preparation of Ag@C nanoparticles. The results of energy disperse spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements all demonstrate that C8 is successfully functionalized on the surface of Ag@C nanoparticles. The combination of an agglomeration effect and the core-shell structure improves the sensitivity and stability of the substrate. The Raman performance of both Ag@C and Ag@C@C8 nanoparticles was evaluated using representative probe molecules such as rhodamine 6G, crystal violet and malachite green. The sensitivity and enhancement factor of Ag@C@C8 were evaluated using folic acid, a non-dye molecule. Additionally, malachite green in several actual water samples was also measured to evaluate the Ag@C@C8 nanoparticles. Then, using crystal violet as a probe molecule, the long-term stability of the Ag@C@C8 nanoparticles was investigated. The results indicate that for four weeks, the intensity deviations of different characteristic peaks were less than 17.5%, and there was no further downward trend. Our strategy partially overcomes the problem of easy oxidation of Ag nanoparticles by coating them with a thin carbon layer, and subsequent functionalization with C8 can increase the SERS sensitivity for certain pollutants due to a condensation effect.

Perovskite solar cells (PSCs) with no charge transport layer (CTL) have drawn great attentions due to their simple device structure and low cost. However, the low efficiency hampers their practical applications. In the study, a novel FASnI3/MAPbI3 heterojunction structure is proposed to replace the conventional MAPbI3 absorber layer for efficient CTL-free PSCs. The numerical tool SCAPS-1D is employed to optimize the proposed structure taking into account multiple device and material parameters, such as layer thickness, doping concentration of MAPbI3, electron affinity of FASnI3 and back electrode work function. After optimization, the highest yielded efficiency of the FASnI3/MAPbI3 bilayer structure is 25.34%, which is 54.9% relatively higher than the conventional MAPbI3 single-layer structure (with an optimal efficiency of 16.36%). The simulation results demonstrate the huge potentials of proposed FASnI3/MAPbI3 heterojunction for constructing efficient CTL-free PSCs and provide inspirations for the future development of CTL-free PSCs.

Ag@C core-shell nanoparticles (NPs) were first prepared by a low-temperature heating-stirring method and subsequently modified with polyethyleneimine (PEI) at different concentrations. Finally, Ag@C@Ag hybrid NPs were prepared by a simple self-assembly procedure, and 24-nm Ag NPs were attached onto the surface of the initially fabricated PEI-modified Ag@C NPs via interaction between the NH2 groups of PEI and Ag. The results demonstrated that rhodamine 6G (R6G) could be detected at a concentration as low as 10−10 M using the Ag@C@Ag NPs as a substrate. To further understand the signal enhancement mechanism, finite-difference time-domain (FDTD) simulations were performed to calculate the electromagnetic field distributions and illustrate the generated Raman hot spots. The FDTD indicated that this enhancement was attributed to the surface plasmon resonance effects of the core Ag NPs in the Ag@C NPs, hot spots between the Ag@C NPs, and external assembly of the 24-nm Ag NPs, as well as between the massive outlayer 24-nm Ag NPs themselves. These fabricated materials were further applied for the detection of folic acid as an actual sample. The outstanding performance of the Ag@C@Ag NPs can be attributed to both the excellent properties of this hybrid substrate and the absorption capability of the carbon layer. Thus, this Ag@C@Ag NP material demonstrates excellent and stable optical properties, and can be used as a surface-enhanced Raman scattering (SERS) substrate in the field of ultrasensitive spectral analysis.

Summary Starch is the most abundant storage carbohydrate in maize kernels and provides calories for humans and other animals as well as raw materials for various industrial applications. Decoding the genetic basis of natural variation in kernel starch content is needed to manipulate starch quantity and quality via molecular breeding to meet future needs. Here, we identified 50 unique single quantitative trait loci (QTLs) for starch content with 18 novel QTLs via single linkage mapping, joint linkage mapping and a genome‐wide association study in a multi‐parent population containing six recombinant inbred line populations. Only five QTLs explained over 10% of phenotypic variation in single populations. In addition to a few large‐effect and many small‐effect additive QTLs, limited pairs of epistatic QTLs also contributed to the genetic basis of the variation in kernel starch content. A regional association study identified five non‐starch‐pathway genes that were the causal candidate genes underlying the identified QTLs for starch content. The pathway‐driven analysis identified ZmTPS9, which encodes a trehalose‐6‐phosphate synthase in the trehalose pathway, as the causal gene for the QTL qSTA4−2, which was detected by all three statistical analyses. Knockout of ZmTPS9 increased kernel starch content and, in turn, kernel weight in maize, suggesting potential applications for ZmTPS9 in maize starch and yield improvement. These findings extend our knowledge about the genetic basis of starch content in maize kernels and provide valuable information for maize genetic improvement of starch quantity and quality.

Correct identification of small hepatocellular carcinomas (HCCs) and benign nodules in cirrhosis remains challenging, quantitative apparent diffusion coefficients (ADCs) have shown potential value in characterization of benign and malignant liver lesions. We aimed to explore the added value of ADCs in the identification of small (≤3 cm) HCCs and benign nodules categorized as Liver Imaging Reporting and Data System (LI-RADS) 3 (LR-3) and 4 (LR-4) in cirrhosis.Ninety-seven cirrhosis patients with 109 small nodules (70 HCCs, 39 benign nodules) of LR-3 and 4 LR-4 based on major and ancillary magnetic resonance imaging features were included. Multiparametric quantitative ADCs of the lesions, including the mean ADC (ADCThe ADCThe addition of quantitative ADCs could improve the identification of small HCC and benign nodules categorized as LR-3 and 4 LR-4 in patients with cirrhosis.