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Centrifugal pump is an important tool for pipeline transportation，and its safety and service life will greatly restrict the cost of pipeline transportation.The centrifugal pump is composed of internal rotor and external diffuser，among which，the external diffuser is welded from steel plates，the weld between the steel plates as the weak link of the diffuser，is a main failure part of the centrifugal pump.Therefore，in this paper，a failed diffuser of an oil transmission station was used as the raw material，scanning electron microscopy (SEM)，energy dispersive spectroscopy (EDS)，and electron back scatter diffraction (EBSD) detection for the welds of the diffuser were conducted，and the failure mechanism of the welds of the diffuser was analyzed from the perspective of microstructure，combining the three detection results and the working environment of the diffuser.Based on EBSD test results，the critical dislocation density ρGND of weld，heat affected zone and substrate was calculated and the strength and toughness of the three positions were quantitatively compared.Results showed that the heat affected zone had the highest strength and toughness，followed by the substrate，and the weld was the lowest.Defects such as slag inclusion，scratch and residual austenite created the initial condition for weld corrosion and cracking.Micro cracks rapidly expanded under the combined action of cyclic stress and corrosive medium，and eventually leading to weld failure of diffuser.The results of this study could provide some reference for the use and manufacture of centrifugal pumps.

Background and purpose: This prospective observational study aimed to investigate the occurrence of avascular necrosis (AVN) of the femoral head in COVID-19 patients through MRI scans. The study examined the patterns of AVN in 110 individuals who had undergone conventional COVID-19 therapy and reported hip discomfort. This study highlights the importance of considering AVN as a potential complication of COVID-19 therapy, particularly in younger patients who experience hip discomfort. Methods: Individuals who had corticosteroid treatment for COVID-19 and experienced hip discomfort during 6 months between January 2022 and August 2022 were included in this study, and an MRI scan was done to observe changes in the hip joint. Results: The results were classified using the Ficat and Arlet classification system. The analysis revealed that AVN was not present in 91.81% of cases. However, Stage I AVN was detected in 4.54% of cases, Stage II AVN in 2.72% of cases, and Stage III AVN in 1.1% of cases. No cases of Stage IV AVN were observed. Conclusions: The study concludes that AVN occurred in 6% of individuals who underwent conventional therapy for COVID-19 and experienced hip discomfort. In these settings (post COVID-19), normal MRI results were more typical, and mild AVN (Stage I) was a frequent finding in MRI scans that were positive. [ABSTRACT FROM AUTHOR]

The alkaline hydrogen evolution reaction (HER) always needs the nearby dual sites of water adsorption and H2 generation, and Ruthenium‐based electrocatalysts are promising alternatives to platinum‐based materials. However, achieving both high efficiency and long‐term stability in the construction of the dual sites is still challenging. Herein, Cu‐doped RuO2 (Cu‐RuO2) is reported and undergoes instant activation for Ru0 production at the low potential state preceding the HER. The Cu2+ ions are demonstrated to work as the switch for obtaining the activated sample of Cu‐RuO2‐AC, which possesses the Ru‐RuO2 structure. The sample of Cu‐RuO2‐AC gives an overpotential of only 19 mV at the current density of 10 mA cm−2 with a Tafel slope of 32.8 mV dec−1. Moreover, at the mass activity of 1 A mgRu−1, it only needs 88 mV, which is lower than the 343 mV of commercial 40% Ru/C, or the 154 mV of activated bare RuO2 (RuO2‐AC). Density functional theory (DFT) calculations reveal that Cu2+ doping activates the nearby Ru4+. A two‐electrode H‐cell device of Cu‐RuO2‐AC||Cu‐RuO2 needs only 1.66 and 1.78 V versus RHE to achieve a current density of 100 and 200 mA cm−2 of overall water splitting. This research can help design more efficient dual‐site HER electrocatalysts. [ABSTRACT FROM AUTHOR]

The use of non‐precious metal materials for catalyzing the hydrogen evolution reaction (HER) holds significant importance for the widespread application of new energy technologies. In this study, we prepare a novel foam nickel (NF) supported NixCoP (NixCoP@NF) nanocrystal through a one‐pot hydrothermal method and high‐temperature phosphorization, involving a straightforward process. Innovatively, we achieve morphology control of NixCoP@NF by altering the Ni : Co ratio to maximize its active surface area. The resulting ′petal‐like′ Ni0.5CoP@NF nanostructure exhibits high activity and long‐term durability in an alkaline medium (1 M KOH), with an overpotential of 58 mV at a current density of 10 mA ⋅ cm−2, a Tafel slope of 60.82 mV ⋅ dec−1, and demonstrates lower impedance compared to most non‐precious metal HER electrocatalysts. Furthermore, the variation in activation energy (Ea) reflects the thermodynamic advantages during the electrolysis process. This work offers a new approach for the development of simple and cost‐effective HER catalysts. [ABSTRACT FROM AUTHOR]

Purpose: Osteoarthritis (OA) is a degenerative joint disease that leads to the destruction of joint function. The aim of this study is to investigate the effects of microRNA‐340‐5p (miR‐340‐5p) and its target gene, FMOD, on the proliferation and apoptosis of chondrocytes in mice with OA through the extracellular signal‐regulated kinase (ERK) signaling pathway. Materials: Twenty healthy C57BL/6J mice aged 15 months with a weight of 50 ± 2 g were selected. Ten mice were treated using a unilateral knee anterior cruciate ligament transection as well as a medial meniscectomy to establish the OA model. Besides, another 10 mice were used as the control group. Methods: A reverse transcription quantitative polymerase chain reaction and Western blot analysis methods were used to examine the expressions of related genes in cells of each group. A 3‐(4,5‐dimethylthiazol‐2‐yl)2,5‐diphenyl tetrazolium bromide assay and flow cytometry were also conducted to evaluate the cell function after transfection had been completed. Results: The expressions of fibromodulin (FMOD), type II collagen (Col II), B‐cell lymphoma‐2 (Bcl‐2), sex‐determining region of Y chromosome (SRY)‐related high‐mobility group‐box gene 9 (Sox9), and proliferating cell nuclear antigen (PCNA) were decreased, whereas the expressions of miR‐340‐5p, runt‐related transcription factor‐2 (Runx2), Bcl‐2‐associated X protein (Bax), and ERK1/2 were elevated in the OA mice. Downregulation of miR‐340‐5p and upregulation of FMOD decreased the expressions of Runx2, Bax, and ERK1/2, and cell apoptosis of chondrocytes, and increased the expressions of FMOD, Col II, Bcl‐2, Sox9, and PCNA, and cell proliferation. Conclusion: This study suggests that downregulation of miR‐340‐5p plays a role in promoting cell proliferation and suppressing cell apoptosis of chondrocytes in OA mice through inhibition of the ERK signaling pathway via the FMOD gene. The downregulation of miR‐340‐5p plays a role in promoting cell proliferation and suppressing cell apoptosis of chondrocytes in osteoarthritis mice through inhibition of the extracellular signal‐regulated kinase signaling pathway via the FMOD gene. [ABSTRACT FROM AUTHOR]