66 research outputs found

    Stochastic Finite Element Method in Mechanical Vibration

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    Stochastic Finite Element for Structural Vibration

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    This paper proposes a new method of calculating stochastic field. It is an improvement of the midpoint method of stochastic field. The vibration equation of a system is transformed to a static problem by using the Newmark method and the Taylor expansion is extended for the structural vibration analysis with uncertain factors. In order to develop computational efficiency and allow for efficient storage, the Conjugate Gradient method (CG) is also employed. An example is given, respectively, and calculated results are compared to validate the proposed methods

    A multicentre study on the clinical characteristics of newborns infected with coronavirus disease 2019 during the omicron wave

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    ObjectiveTo investigate the clinical characteristics and outcomes of newborns infected with coronavirus disease 2019 (COVID-19) during the Omicron wave.MethodsFrom December 1, 2022, to January 4, 2023, clinical data were collected from neonates with COVID-19 who were admitted to 10 hospitals in Foshan City, China. Their epidemiological histories, clinical manifestations and outcomes were analysed. The neonates were divided into symptomatic and asymptomatic groups. The t test or χ2 test was used for comparisons between groups.ResultsA total of 286 children were diagnosed, including 166 males, 120 females, 273 full-term infants and 13 premature infants. They were 5.5 (0–30) days old on average when they were admitted to the hospital. These children had contact with patients who tested positive for COVID-19 and were infected through horizontal transmission. This study included 33 asymptomatic and 253 symptomatic patients, among whom 143 were diagnosed with upper respiratory tract infections and 110 were diagnosed with pneumonia. There were no severe or critical patients. Fever (220 patients) was the most common clinical manifestation, with a duration of 1.1 (1–6) days. The next most common clinical manifestations were cough with nasal congestion or runny nose (4 patients), cough (34 patients), poor appetite (7 patients), shortness of breath (15 patients), and poor general status (1 patient). There were no significant abnormalities in routine blood tests among the neonates infected with COVID-19 except for mononucleosis. However, compared with the asymptomatic group, in the symptomatic group, the leukocyte and neutrophil granulocyte counts were significantly decreased, and the monocyte count was significantly increased. C-reactive protein (CRP) levels were significantly increased (≥10 mg/L) in 9 patients. Myocardial enzyme, liver function, kidney function and other tests showed no obvious abnormalities.ConclusionsIn this study, neonates infected with the Omicron variant were asymptomatic or had mild disease. Symptomatic patients had lower leucocyte and neutrophil levels than asymptomatic patients

    Identification of RegIV as a Novel GLI1 Target Gene in Human Pancreatic Cancer

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    GLI1 is the key transcriptional factor in the Hedgehog signaling pathway in pancreatic cancer. RegIV is associated with regeneration, and cell growth, survival, adhesion and resistance to apoptosis. We aimed to study RegIV expression in pancreatic cancer and its relationship to GLI1.GLI1 and RegIV expression were evaluated in tumor tissue and adjacent normal tissues of pancreatic cancer patients and 5 pancreatic cancer cell lines by qRT-PCR, Western blot, and immunohistochemistry (IHC), and the correlation between them. The GLI1-shRNA lentiviral vector was constructed and transfected into PANC-1, and lentiviral vector containing the GLI1 expression sequence was constructed and transfected into BxPC-3. GLI1 and RegIV expression were evaluated by qRT-PCR and Western blot. Finally we demonstrated RegIV to be the target of GLI1 by chromatin immunoprecipitation (CHIP) and electrophoretic mobility shift assays (EMSA).The results of IHC and qRT-PCR showed that RegIV and GLI1 expression was higher in pancreatic cancer tissues versus adjacent normal tissues (p<0.001). RegIV expression correlated with GLI1 expression in these tissues (R = 0.795, p<0.0001). These results were verified for protein (R = 0.939, p = 0.018) and mRNA expression (R = 0.959, p = 0.011) in 5 pancreatic cancer cell lines. RegIV mRNA and protein expression was decreased (94.7±0.3%, 84.1±0.5%; respectively) when GLI1 was knocked down (82.1±3.2%, 76.7±2.2%; respectively) by the RNAi technique. GLI1 overexpression in mRNA and protein level (924.5±5.3%, 362.1±3.5%; respectively) induced RegIV overexpression (729.1±4.3%, 339.0±3.7%; respectively). Moreover, CHIP and EMSA assays showed GLI1 protein bound to RegIV promotor regions (GATCATCCA) in pancreatic cancer cells.GLI1 promotes RegIV transcription by binding to the RegIV gene promoter in pancreatic cancer

    The genome and transcriptome of Japanese flounder provide insights into flatfish asymmetry

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    Flatfish have the most extreme asymmetric body morphology of vertebrates. During metamorphosis, one eye migrates to the contralateral side of the skull, and this migration is accompanied by extensive craniofacial transformations and simultaneous development of lopsided body pigmentation(1-5). The evolution of this developmental and physiological innovation remains enigmatic. Comparative genomics of two flatfish and transcriptomic analyses during metamorphosis point to a role for thyroid hormone and retinoic acid signaling, as well as phototransduction pathways. We demonstrate that retinoic acid is critical in establishing asymmetric pigmentation and, via cross-talk with thyroid hormones, in modulating eye migration. The unexpected expression of the visual opsins from the phototransduction pathway in the skin translates illumination differences and generates retinoic acid gradients that underlie the generation of asymmetry. Identifying the genetic underpinning of this unique developmental process answers long-standing questions about the evolutionary origin of asymmetry, but it also provides insight into the mechanisms that control body shape in vertebrates.National Natural Science Foundation of China [31130057, 31461163005, 31530078, 31472269, 31472262, 31472273]; State 863 High Technology R&D Project of China [2012AA092203, 2012AA10A408, 2012AA10A403-2]; Education and Research of Guangdong Province [2013B090800017]; Taishan Scholar Climb Project Fund of Shandong of China; Taishan Scholar Project Fund of Shandong of China for Young Scientists; Shanghai Universities First-class Disciplines Project of Fisheries; Program for Professor of Special Appointment (Eastern Scholar) at the Shanghai Institutions of Higher Learning; Shanghai Municipal Science, Special Project on the Integration of Industryinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/publishedVersio

    Polar localization of CheO under hypoxia promotes Campylobacter jejuni chemotactic behavior within host.

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    Campylobacter jejuni is a food-borne zoonotic pathogen of worldwide concern and the leading cause of bacterial diarrheal disease. In contrast to other enteric pathogens, C. jejuni has strict growth and nutritional requirements but lacks many virulence factors that have evolved for pathogenesis or interactions with the host. It is unclear how this bacterium has adapted to an enteric lifestyle. Here, we discovered that the CheO protein (CJJ81176_1265) is required for C. jejuni colonization of mice gut through its role in chemotactic control of flagellar rotation in oxygen-limiting environments. CheO interacts with the chemotaxis signaling proteins CheA and CheZ, and also with the flagellar rotor components FliM and FliY. Under microaerobic conditions, CheO localizes at the cellular poles where the chemosensory array and flagellar machinery are located in C. jejuni and its polar localization depends on chemosensory array formation. Several chemoreceptors that mediate energy taxis coordinately determine the bipolar distribution of CheO. Suppressor screening for a ΔcheO mutant identified that a single residue variation in FliM can alleviate the phenotype caused by the absence of CheO, confirming its regulatory role in the flagellar rotor switch. CheO homologs are only found in species of the Campylobacterota phylum, mostly species of host-associated genera Campylobacter, Helicobacter and Wolinella. The CheO results provide insights into the complexity of chemotaxis signal transduction in C. jejuni and closely related species. Importantly, the recruitment of CheO into chemosensory array to promote chemotactic behavior under hypoxia represents a new adaptation strategy of C. jejuni to human and animal intestines

    Excellent low temperature performance for total benzene oxidation over mesoporous CoMnAl composited oxides from hydrotalcites

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    Mesoporous CoMnAl mixed metal oxide catalysts with various Co/Mn atomic ratios have been obtained by calcination at 450 degrees C of layered double hydroxide (LDH) precursors prepared by the NH4OH co-precipitation-hydrothermal method without distinct MnCO3 peaks. The catalysts exhibited high efficiency for total oxidation of volatile organic compounds (VOCs). The physicochemical properties of the catalysts were characterized using several analytical techniques. Among them, CoMn2AlO shows the optimal activity and the temperature required to achieve a benzene conversion of 90% (T-90) was about 238 degrees C, with a reaction rate and activity energy (E-a) of 0.24 mmol g(cat)(-1) h(-1) and 65.77 kJ mol(-1) respectively. This temperature was 47 degrees C lower than that on the Co3AlO sample with a tower reaction rate of 0.19 mmol g(cat)(-1) h(-1) and a higher E-a 130.31 kJ mol(-1) at a high space velocity (SV = 60 000 mL g(-1) h(-1)). The effects of calcination temperature on the textural properties and catalytic activity of the CoMn2AlO catalyst were further investigated. The as-prepared CoMn2AlO-550 sample displayed superior catalytic activity, with T-90 at 208 degrees C, compared CoMn2AlO-450. The formation of a solid solution with high surface area, rich oxygen vacancies, high Mn4+/Mn3+ and Co3+/Co2+ ratios and low-temperature reducibility made a great contribution to the significant improvement of the catalytic activity

    Downregulation of UBAP2L Inhibits the Epithelial-Mesenchymal Transition via SNAIL1 Regulation in Hepatocellular Carcinoma Cells

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    Background/Aims: Dysregulation of ubiquitin-associated protein 2-like (UBAP2L) has been reported in tumors, but its role in hepatocellular carcinoma (HCC) progression is unclear. Methods: The expression levels of UBAP2L in HCC tissues and HCC cell lines were detected by western blot and quantitative real-time (qRT) PCR. The effects of UBAP2L expression on HCC cell biological traits, including migration and invasion, were investigated by wound healing assay and matrigel transwell assay. Simultaneously, the expression of epithelial-mesenchymal transition (EMT) markers including E-cadherin, CK-18, N-cadherin, Vimentin, Claudin7 and the promoter activity of E-cadherin were detected by western blot and qRT-PCR. Subsequently, role of SNAIL1 in UBAP2L-mediated EMT and the mechanism underlying UBAP2L-mediated SNAIL1 expression were further investigated. Results: UBAP2L was overexpressed in human HCC tissues compared with peri-tumoral tissues. Downregulation of UBAP2L inhibited migration, invasion and the EMT in highly metastatic HCC cell lines. Furthermore, UBAP2L knockdown inhibited expression of the transcriptional repressor SNAIL1 and its ability to bind to the E-cadherin promoter via SMAD2 signaling pathway, which in turn resulted in increased E-cadherin expression. Additionally, bioinformatics analysis showed that expression of UBAP2L is correlated with poor prognosis in patients with HCC. Conclusions: UBAP2L plays a critical role in maintenance of the metastatic ability of HCC cells via SNAIL1 Regulation and is predictive of a poor clinical outcome

    Safe Decision-making for Lane-change of Autonomous Vehicles via Human Demonstration-aided Reinforcement Learning

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    Decision-making is critical for lane change in autonomous driving. Reinforcement learning (RL) algorithms aim to identify the values of behaviors in various situations and thus they become a promising pathway to address the decision-making problem. However, poor runtime safety hinders RL-based decision-making strategies from complex driving tasks in practice. To address this problem, human demonstrations are incorporated into the RL-based decision-making strategy in this paper. Decisions made by human subjects in a driving simulator are treated as safe demonstrations, which are stored into the replay buffer and then utilized to enhance the training process of RL. A complex lane change task in an off-ramp scenario is established to examine the performance of the developed strategy. Simulation results suggest that human demonstrations can effectively improve the safety of decisions of RL. And the proposed strategy surpasses other existing learning-based decision-making strategies with respect to multiple driving performances
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