136 research outputs found

    Structural damage detection based on cloud model and Dempster-Shafer evidence theory

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    Cloud model and D-S theory have been widely used in uncertainty reasoning. Meanwhile, modal strain energy and Inner Product Vector are also utilized as damage-sensitive features to detect structural damage. In this paper, a new structural damage identification approach is proposed based on Dempster-Shafer theory and cloud model. Cloud models were created to make uncertainty reasoning in damage structures by modal strain energy and the Inner Product Vector of acceleration. Then the results of the two methods were combined by using the Dempster-Shafer theory. Due to the classical D-S theory involves counter – intuitive behavious when the high conflicting evidences exists, the distance function was introduced to correct the conflict factor K and combine the evidences. Moreover, a model of simple beam was created to verify the feasibility and accuracy for the single-damage and the multiple-damage. The effects of noise on damage detection were investigated simultaneously. The results show that the method has strong anti-noise ability and high accuracy

    Haemophilus parasuis Infection Disrupts Adherens Junctions and Initializes EMT Dependent on Canonical Wnt/β-Catenin Signaling Pathway

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    In this study, animal experimentation verified that the canonical Wnt/β-catenin signaling pathway was activated under a reduced activity of p-β-catenin (Ser33/37/Thr41) and an increased accumulation of β-catenin in the lungs and kidneys of pigs infected with a highly virulent strain of H. parasuis. In PK-15 and NPTr cells, it was also confirmed that infection with a high-virulence strain of H. parasuis induced cytoplasmic accumulation and nuclear translocation of β-catenin. H. parasuis infection caused a sharp degradation of E-cadherin and an increase of the epithelial cell monolayer permeability, as well as a broken interaction between β-catenin and E-cadherin dependent on Wnt/β-catenin signaling pathway. Moreover, Wnt/β-catenin signaling pathway also contributed to the initiation of epithelial-mesenchymal transition (EMT) during high-virulence strain of H. parasuis infection with expression changes of epithelial/mesenchymal markers, increased migratory capabilities as well as the morphologically spindle-like switch in PK-15 and NPTr cells. Therefore, we originally speculated that H. parasuis infection activates the canonical Wnt/β-catenin signaling pathway leading to a disruption of the epithelial barrier, altering cell structure and increasing cell migration, which results in severe acute systemic infection characterized by fibrinous polyserositis during H. parasuis infection

    Autophagy Is a Defense Mechanism Inhibiting Invasion and Inflammation During High-Virulent Haemophilus parasuis Infection in PK-15 Cells

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    Bacterial infections activate autophagy and autophagy restricts pathogens such as Haemophilus parasuis through specific mechanisms. Autophagy is associated with the pathogenesis of H. parasuis. However, the mechanisms have not been clarified. Here, we monitored autophagy processes using confocal microscopy, western blot, and transmission electron microscopy (TEM) and found that H. parasuis SH0165 (high-virulent strain) but not HN0001 (non-virulent strain) infection enhanced autophagy flux. The AMPK/mTOR autophagy pathway was required for autophagy initiation and ATG5, Beclin-1, ATG7, and ATG16L1 emerged as important components in the generation of the autophagosome during H. parasuis infection. Moreover, autophagy induced by H. parasuis SH0165 turned to fight against invaded bacteria and inhibit inflammation. Then we further demonstrated that autophagy blocked the production of the cytokines IL-8, CCL4, and CCL5 induced by SH0165 infection through the inhibition of NF-ÎşB, p38, and JNK MAPK signaling pathway. Therefore, our findings suggest that autophagy may act as a cellular defense mechanism in response to H. parasuis and provide a new way that autophagy protects the host against H. parasuis infection

    Knowledge and attitudes of healthcare workers in Chinese intensive care units regarding 2009 H1N1 influenza pandemic

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    <p>Abstract</p> <p>Background</p> <p>To describe the knowledge and attitudes of critical care clinicians during the 2009 H1N1 influenza pandemic.</p> <p>Methods</p> <p>A survey conducted in 21 intensive care units in 17 provinces in China.</p> <p>Results</p> <p>Out of 733 questionnaires distributed, 695 were completed. Three hundred and fifty-six respondents (51.2%) reported their experience of caring for H1N1 patients. Despite the fact that 88.5% of all respondents ultimately finished an H1N1 training program, only 41.9% admitted that they had the knowledge of 2009 H1N1 influenza. A total of 572 respondents (82.3%) expressed willingness to care for H1N1 patients. Independent variables associated with increasing likelihood to care for patients in the logistic regression analysis were physicians or nurses rather than other professionals (odds ratio 4.056 and 3.235, p = 0.002 and 0.007, respectively), knowledge training prior to patient care (odds ratio 1.531, p = 0.044), and the confidence to know how to protect themselves and their patients (odds ratio 2.109, p = 0.001).</p> <p>Conclusion</p> <p>Critical care clinicians reported poor knowledge of H1N1 influenza, even though most finished a relevant knowledge training program. Implementation of appropriate education program might improve compliance to infection control measures, and willingness to work in a pandemic.</p

    27-Hydroxycholesterol Contributes to Lysosomal Membrane Permeabilization-Mediated Pyroptosis in Co-cultured SH-SY5Y Cells and C6 Cells

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    Purpose: Emerging evidence suggests that 27-Hydroxycholesterol (27-OHC) causes neurodegenerative diseases through the induction of cytotoxicity and cholesterol metabolism disorder. The objective of this study is to determine the impacts of 27-OHC on lysosomal membrane permeabilization (LMP) and pyroptosis in neurons in the development of neural degenerative diseases.Methods: In this study, SH-SY5Y cells and C6 cells were co-cultured in vitro to investigate the influence of 27-OHC on the function of lysosome, LMP and pyroptosis related factors in neuron. Lyso Tracker Red (LTR) was used to detect the changes of lysosome pH, volume and number. Acridine orange (AO) staining was also used to detect the LMP in neurons. Then the morphological changes of cells were observed by a scanning electron microscope (SEM). The content of lysosome function associated proteins [including Cathepsin B (CTSB), Cathepsin D (CTSD), lysosomal-associated membraneprotein-1 (LAMP-1), LAMP-2] and the pyroptosis associated proteins [including nod-like recepto P3 (NLRP3), gasdermin D (GSDMD), caspase-1 and interleukin (IL)-1β] were detected through Western blot.Results: Results showed higher levels of lysosome function associated proteins, such as CTSB (p &lt; 0.05), CTSD (p &lt; 0.05), LAMP-1 (p &lt; 0.01), LAMP-2; p &lt; 0.01) in 27-OHC treated group than that in the control group. AO staining and LTR staining showed that 27-OHC induced lysosome dysfunction with LMP. Content of pyroptosis related factor proteins, such as GSDMD (p &lt; 0.01), NLRP3 (p &lt; 0.001), caspase-1 (p &lt; 0.01) and IL-1β (p &lt; 0.01) were increased in 27-OHC treated neurons. Additionally, CTSB was leaked through LMP into the cytosol and induced pyroptosis. Results from the present study also suggested that the CTSB is involved in activation of pyroptosis.Conclusion: Our data indicate that 27-OHC contributes to the pathogenesis of cell death by inducing LMP and pyroptosis in neurons

    Cases report: MRI findings of asymptomatically familial subependymal heterotopia with filamin A gene abnormality

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    Subependymal heterotopia (SEH) is a rare neuronal migration disorder consisting of gray matter nodules along the lateral ventricular walls and is often associated with other brain malformations. Despite most SEH cases showing epilepsy during their lifetimes, very few patients with asymptomatically familial SEH tend to cause misdiagnosis or missed diagnosis. We present four familial SEH cases without any positive symptoms and medical history, including two fetuses, who were diagnosed by MRI and confirmed by genetic testing with mutation of filamin A. This report emphasizes the role of MRI in the recognition of SEH at an early age of gestation and in asymptomatically familial SEH. MRI provides a fast, repeatable, reliable, and cheap choice for detecting and screening familial SEH

    Engineering hibiscus-like riboflavin/ZIF-8 microsphere composites to enhance transepithelial corneal cross-linking

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    Riboflavin-5-phosphate (RF) is the most commonly used photosensitizer in corneal cross-linking (CXL), but its hydrophilicity and negative charge limit its penetration through the corneal epithelium into the stroma. To enhance the corneal permeability of RF and promote its efficacy in the treatment of keratoconus, novel hibiscus-like RF@ZIF-8 microsphere composites [6RF@ZIF-8 NF (nanoflake)] are prepared using ZIF-8 nanomaterials as carriers, which are characterized by their hydrophobicity, positive potential, biocompatibility, high loading capacities, and large surface areas. Both hematoxylin and eosin endothelial staining and TUNEL assays demonstrate excellent biocompatibility of 6RF@ZIF-8 NF. In in vivo studies, the 6RF@ZIF-8 NF displayed excellent corneal permeation, and outstanding transepithelial CXL (TE-CXL) efficacy, slightly better than the conventional CXL protocol. Furthermore, the special hibiscus-like structures of 6RF@ZIF-8 NF meant that it has better TE-CXL efficacy than that of 6RF@ZIF-8 NP (nanoparticles) due to the larger contact area with the epithelium and the shorter RF release passage. These results suggest that the 6RF@ZIF-8 NF are promising for transepithelial corneal cross-linking, avoiding the need for epithelial debridement

    Seismic Stability for 3D Two-Step Slope Governed by Non-Linearity in Soils Using Modified Pseudo-Dynamic Approach

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    Seismic events are an active factor in causing slope instability, and the existing pseudo-dynamic method ignores some practical engineering conditions. In this paper, the seismic stability of three-dimensional (3D) two-step slopes is evaluated utilizing the modified pseudo-dynamic method based on the kinematical approach of limit analysis, in which the nonlinear characteristics of soil are considered using the generalized tangent technique. A 3D horn-like rotational failure mechanism is established to solve internal energy dissipation and external force work, in which the seismic work is considered in addition to the soil weight work and obtained by the layer-wise summation method. Based on the force-increase technique, the analytical expression for the safety factor (FS) of 3D two-step slopes is derived more readily. To verify the reliability of the new expression, the present results are compared with already posted solutions and the original pseudo-dynamic solutions. Ultimately, the sensitivity discussions are carried out to investigate the impacts of various factors on slope stability. This has some significance for the design and safety of 3D two-step slopes

    Low-Content Quantitation in Entecavir Tablets Using 1064 nm Raman Spectroscopy

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    The nondestructive and high sensitive analysis of a low content of an active pharmaceutical ingredient (API) was a difficult problem, especially in a complex system of pharmaceutical formulations. In this paper, a rapid and no sample preparation method was developed, which used a 1064 nm Raman spectrometer to detect entecavir monohydrate (ETV-H) in Baraclude tablets. Entecavir was a drug approved by FDA for the treatment of chronic hepatitis B and became the first choice in the market. The wavelength selection results displayed that the signal-to-background ratio of the Raman spectrum with 1064 nm excitation wavelength was 14 times that of the commonly used 785 nm wavelength. The partial least squares (PLS) method was used to calibrate concentration models containing 0.1% to 1.0% w/w% ETV-H in calibration set samples. Different preprocessing methods were used to eliminate the background interference and extract more spectral information. Calibration samples were used to choose the best performing model. Then, all the calibration samples combined with the best performing models’ parameters successfully predicted the content of ETV-H in Baraclude tablets. Combining baseline processing and standard normal variate (SNV) with PLS, the model showed a good result with an R2 of 0.973, RMSEC of 0.05%, and RMSEP of 0.03% on the spectral region of 1350–1700 cm−1. The limit of detection of this model was 0.17%. These results showed that 1064 nm Raman spectroscopy technology could be an alternative analytical procedure to quantify low-content API in intact tablets
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