Polymers (Basel)
October 2024
Abnormal heating will reduce the insulation performance of composite insulators or even cause insulator fracture, and the abnormal heating phenomenon is more serious under high-humidity conditions. Therefore, in this paper, the voltage withstand test of abnormal heating composite insulators caused by aging and damp sheath, decay-like core rod, and contamination were carried out under different ambient humidity. The heating and discharge of composite insulators were observed by infrared thermal imager and ultraviolet imager, and its temperature characteristics were analyzed from the aspects of heating range, heating shape, and temperature difference.
View Article and Find Full Text PDFComposite insulators have been widely used in power grids due to their excellent electrical-external-insulation performance. Long-term operation at high voltage levels accelerates the aging of composite insulators; however, there is a scarcity of research on aged composite insulators operating at 500 kV for over ten years. In this paper, the mechanical, electrical, and microscopic properties were tested on different sheds along a 500 kV composite insulator that had been running for 18 years.
View Article and Find Full Text PDFThe surfaces of lotus leaves with micro- and nano-waxy cuticle structures are superhydrophobic and possess a self-healing ability to regain hydrophobicity after damage. Inspired by this phenomenon, the problem of water-repellent coatings used in natural environments failing to perform after damage can be solved if these coatings are endowed with rapid self-repair and self-growth functions. However, there has been almost no exploration into the hydrophobicity self-repair process in lotus leaves.
View Article and Find Full Text PDFEthnopharmacological Relevance: Pi-pa-run-fei-tang (PPRFT), a traditional Chinese medicine formula with long-standing history, demonstrated beneficial effect on chronic cough. However, the mechanism underlying efficacy unclear. In current research, we explored the impact and molecular mechanism of chronic cough mouse stimulating with capsaicin combined with ammonia.
View Article and Find Full Text PDFSilicone rubber insulators are widely used in power grids because of their excellent performance, but aging has been an inevitable problem of silicone rubber, especially in extreme conditions, such as acidic conditions. In order to clarify the performance changes in silicone rubber in an acidic environment, this paper uses the developed acid-resistant silicone rubber sheet and common silicone rubber samples as the research objects, and conducts an aging comparison test on them in a natural acidic environment. The electrical properties, physical properties, and chemical properties of the two types of silicone rubber specimens with different aging times are analyzed to obtain the performance characteristics of silicone rubber under a natural acidic environment.
View Article and Find Full Text PDFResin-impregnated paper (RIP) bushing has gained significant interest due to its extended application in Extra High Voltage (EHV) and Ultra High Voltage (UHV) electricity transmission systems. However, the design criterion of its overall structure, the geometry parameters of the condenser layers, and stress release devices, etc., are still not fully understood.
View Article and Find Full Text PDFMost malignant hepatic nodules (MHNs) eventually progress to hepatocellular carcinoma (HCC). However, assessment of the risk of malignancy in high-risk groups of patients with hepatic nodules remains a challenge. This study aimed to develop and validate a simple scoring system to predict the risk of development of MHNs.
View Article and Find Full Text PDFPolymer insulators using silicone rubber materials as sheds and sheaths are widely used in power systems to replace traditional porcelain and glass insulators which are heavy, inconvenient to install, and prone to pollution flashover. However, in recent years, polymer insulators that have been operating in harsh outdoor environments for many years have experienced different degrees of aging. The aging degree and aging products of silicone rubber are the focus of research.
View Article and Find Full Text PDFComposite insulators operate in harsh field environments all year round. Their various properties and states of aging require attention. It is important to study the performance changes of composite insulator sheds after aging to evaluate the life of insulators operating on grids.
View Article and Find Full Text PDFThe safety and stability of power systems are seriously threatened by the decay-like fracture of composite insulators. This paper analyzes the aging characteristics (physical properties, NMR, and FTIR) of the silicone rubber sheds of the decay-like fractured insulator. The same V-string insulator and a new insulator are used for comparison.
View Article and Find Full Text PDFThe dynamic behaviour of rain droplets on the insulator surface is a key measure to its reliability and performance. This is due to the fact that the presence and motion of rain droplets cause intensive discharge activities, such as corona and low current arcing, which accelerate the ageing process and flashovers. This article aims to investigate and characterize the movement of a rain droplet placed on an inclined insulator surface subject to an intensive electric field.
View Article and Find Full Text PDFLipoxinA4 (LXA4) is a well-known key mediator of endogenous anti-inflammation and of the resolution of inflammation. Considerable oxidative stress occurs during inflammation due to the generation of reactive oxidative species (ROS). Moreover, high levels of uric acid (UA) contribute to endothelial cell dysfunction, which can promote disease-related morbidity, and NADPH oxidase-derived ROS are crucial regulatory factors in these responses.
View Article and Find Full Text PDFIn recent years, the performances of rubber composite insulators, which operate in the coastal foggy regions, have attracted researchers' concern because of the observation of their degradation. In this paper, salt-fog experiments with DC test voltage of high-temperature vulcanized (HTV) silicone rubber (SR) have been conducted. The electrical strength and material performances of samples with salt-fog treatment were focused on.
View Article and Find Full Text PDFAt present, the majority of methods used for uric acid (UA) detection are not able to meet the detection requirements with speed, accuracy, high sensitivity, high specificity, a wide linear range or a low cost. Compared with other methods, the electrochemical method has a high sensitivity and fast detection. The present study aimed to identify an electrochemical sensor with high sensitivity, fast detection and a wide linear range for the detection of UA.
View Article and Find Full Text PDFBackground: T-helper 22 (Th22) cells are involved in host immunity against pathogen invasion and have been implicated in the pathogenesis of inflammatory diseases. However, the roles of Th22 cells in acute gouty arthritis remain unclear.
Methods: A case-control study was employed to illustrate the clinical significance of Th22 cells in acute gouty arthritis.
Human epididymis protein 4 (HE4) is one of the best-known tumor markers for ovarian cancer (OC). Emerging evidence indicates that the evaluation of serum HE4 (S-HE4) levels may be problematic when patients have chronic kidney disease (CKD). Assaying urine for HE4 levels is non-invasive alternative for the diagnosis of OC.
View Article and Find Full Text PDFSichuan Da Xue Xue Bao Yi Xue Ban
September 2013
Objective: To explore the oxidative mechanism of uric acid (UA) induced CRP expression in human umbilical vein endothelial cells.
Methods: Different concentrations of UA (0 mg/dL, 4 mg/dL, 8 mg/dL, 12 mg/dL, 16 mg/dl) were incubated 12 h with HUVECs, and HUVECs were stimulated with 12 mg/dl. UA for different times (6 h, 12 h, 24 h, 48 h).
To analyze the levels of oxidized low density lipoprotein (ox-LDL) and inflammatory cytokines in the plasma of gout patients. The levels of ox-LDL, hypersensitive C-reactive protein (hs-CRP), interleukin-1β, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured in the plasma of 41 gout patients [28 in acute phase episode, 13 in intermittent phase (IP)], and in 40 healthy controls. The relationship between ox-LDL and inflammation was also explored by measuring the levels of several pro-inflammatory cytokines in the plasma.
View Article and Find Full Text PDFThe p63 gene, a member of the p53 gene family, has two different promoter usage‑generating proteins that contain or lack (ΔN) an NH2‑terminus. Although p53 and p63 have high sequence and structural similarities, the molecules differ in function and expression profiles. p63 is critical for the development of epithelial organs or tissues, including the epidermis and other squamous epithelia, as well as the salivary, lachrymal, mammary and prostate glands and the urothelium.
View Article and Find Full Text PDFGout patients have a high incidence of atherosclerotic coronary heart disease. Low serum paraoxonase (PON) activity is considered a risk factor for atherosclerosis. The relationships among paraoxonase-1 (PON1) activity, oxidative stress parameters, and atherosclerosis in gout is not known.
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