Study on Vibration Control of Double Motor Refrigeration Unit in Nuclear Power Plant

In order to solve the problem of excessive vibration during the operation of the refrigeration unit in nuclear power plant, taking the double motor refrigeration unit in operation as the research object, we studied the effective measures to reduce the vibration and improve the stiffness of the double motors in the near resonance region. On the basis of theoretical calculation, the weaknesses of the equipment stiffness were reinforced and reconstructed, and the secondary analysis and calculation of the stiffness and seismic performance of the reformed refrigeration unit were carried out to determine the feasibility of the optimization scheme. Based on the analysis, we optimized the equipment. After that, there was a significant decrease in the vibration of the refrigeration unit. The vibration measurement results indicated that the vibration value of the unit has dropped to the qualified range, effectively avoiding the equipment damage caused by excessive vibration. We provided a complete set of analysis ideas for the research and solution of vibration problems of rotating equipment in nuclear power plant

Yiqi Huoxue Decoction modifies the expression of myocardial cytoskeleton-associated proteins by regulating the AMPK signaling pathway in H9c2 cells exposed to hypoxic conditions

Background: In myocardial ischemia, hypoxia leads to destruction of the cytoskeleton, and especially the imbalance of microtubule polymerization-depolymerization, which seriously affects the structure and function of cardiomyocytes. We previously showed that a Yiqi Huoxue Decoction (YQHX) improves mitochondrial function and decreases anti-oxidative effects in hypoxia-induced H9c2 cell injury. Therefore, in this study we investigated whether YQHX protects against hypoxia-induced damage by decreasing damage to the cardiac cytoskeleton. Methods: After reaching 70%–80% confluence, H9c2 cells were synchronized in serum-free Dulbecco's Modified Eagle Medium for 6 hours, then divided into control, model, and YQHX (100, 200, 400 μg/mL) groups, which were then grown in a hypoxic atmosphere for 12 hours. Cardiac cell viability was assessed using an xCELLigence system. The levels of lactate dehydrogenase, maleic dialdehyde, and superoxide dismutase in H9c2 cell supernatants were measured. Hoechst 33258 staining was employed to observe cardiac cell apoptosis. Confocal microscopy, immunofluorescence, and western blot analysis were performed to evaluate the protective effects of the YQHX against hypoxia-induced injury in the H9c2 cell line. Results: Cells that were pretreated with YQHX were more able to maintain their microtubule structure in the early stages of hypoxia and had better myocardial fitness in response to hypoxia compared with cells that were not pretreated. However, hypoxia-induced upregulation of α-tubulin and β-tubulin expression antagonized the protective effect of YQHX (100 μg/mL). In addition, YQHX (100 μg/mL) treatment significantly upregulated MAP4 protein expression (P = .003) and downregulated p-AMPKα protein expression (P < .001) compared with the model group. Conclusion: The results indicate that YQHX plays a role in protecting against oxidative stress injury and apoptosis in H9c2 cells. Notably, our results suggested that the YQHX could mitigate the damage to the cardiac cytoskeleton and the dysregulation of AMPK-related protein signaling pathways that are induced by hypoxia. Keywords: Yiqi huoxue Decoction, Hypoxia, Myocardial cytoskeleton, Microtubules, AMP

Glycosylated, Lipid-Binding, CDR-Like Domains of SARS-CoV-2 ORF8 Indicate Unique Sites of Immune Regulation

ABSTRACT The outbreak of the novel coronavirus SARS-CoV-2 has posed a significant threat to human health and the global economy since the end of 2019. Unfortunately, due to the virus’s rapid evolution, preventingand controlling the epidemic remains challenging. The ORF8 protein is a unique accessory protein in SARS-CoV-2 that plays a crucial role in immune regulation, but its molecular details are still largely unknown. In this study, we successfully expressed SARS-CoV-2 ORF8 in mammalian cells and determined its structure using X-ray crystallography at a resolution of 2.3 Å. Our findings reveal several novel features of ORF8. We found that four pairs of disulfide bonds and glycosylation at residue N78 are essential for stabilizing ORF8’s protein structure. Additionally, we identified a lipid-binding pocket and three functional loops that tend to form CDR-like domains that may interact with immune-related proteins to regulate the host immune system. On cellular experiments also demonstrated that glycosylation at N78 regulats of ORF8’s ability to bind to monocytes cells. These novel features of ORF8 provide structural insights to into its immune-related function and may serve as new targets for developing ORF8-mediated immune regulation inhibitors. IMPORTANCE COVID-19, caused by the novel coronavirus SARS-CoV-2 virus, has triggered a global outbreak. The virus’s continuous mutation increases its infectivity and may be directly related to the immune escape response of viral proteins. In this study, we used X-ray crystallography to determine the structure of SARS-CoV-2 ORF8 protein, a unique accessory protein expressed in mammalian cells, at a resolution of 2.3 Å. Our novel structure reveals important structure details that shed light on ORF8’s involvement in immune regulation, including conservation disulfide bonds, a glycosylation site at N78, a lipid-binding pocket, and three functional loops that tend to form CDR-like domains that may interact with immune-related proteins to modulate the host immune system. We also conducted preliminary validation experiments on immune cells. These new insights into ORF8’s structure and function provide potential targets for developing inhibitors to block the ORF8-mediated immune regulation between viral protein and host, ultimately contributing to the development of novel therapeutics for COVID-19

Magnetoelectric sensor with miniature universal tunable bias magnetic circuit

National Natural Science Funding of China [50702047, 51202204]; State Grid Jinzhou Electron Power Supply CompanyThis paper presents a miniature alternating magnetic field sensor made from magnetoelectric (ME) laminated materials with a universal tunable bias magnetic circuit. By adjusting the width of the bypass passage in the bias magnetic circuit, the magnetic flux in the ME materials could be tuned and make the ME sensor work under the optimal bias magnetic field. In our design, the sensor's dimension is as small as 8 mm along the detecting direction. Due to the excellent linearity when measuring low frequency alternating magnetic fields of 50 Hz, this miniature sensor is ideally suited for power line current measurement. (C) 2013 AIP Publishing LLC