Lamb waves defects imaging research based on multi-parameter compensation and pixel optimization

Ultrasonic guided waves detecting technology has promising application prospects in structural health monitoring. In order to detect defects in the aluminum sheet, a kind of defect localization imaging algorithm, combining multi-parameter compensation and pixel partitioning optimization is proposed in this paper. Based on the analysis of imaging principles, the waveform signal of time domain was mapped onto the wavenumber domain through a backward propagation compensation, so dispersion parameters can be compensated. Reference signal compensation can be achieved by the baseline signal differential method from wavenumber domain, which overcame influences of environmental changes. During the imaging process, a reasonable threshold was used for pixel partitioning and optimization to improve image quality. Experimental results demonstrated that positioning error about the algorithm is small, defects imaging of sheet is clear and intuitive, this optimization and compensation of guided-wave defects imaging can be used in structural health monitoring

Dynamic Response of Base-Isolated Concrete Rectangular Liquid-Storage Structure Under Large Amplitude Sloshing

Considering concrete nonlinearity, the wave height limit between small and large amplitude sloshing is defined based on the Bernoulli equation. Based on Navier-Stokes equations, the mathematical model of large amplitude sloshing is established for a Concrete Rectangle Liquid-Storage Structure (CRLSS). The results show that the seismic response of a CRLSS increases with the increase of seismic intensity. Under different seismic fortification intensities, the change in trend of wave height, wallboard displacement, and stress are the same, but the amplitudes arc not. The areas of stress concentration appear mainly at the connections between the wallboards, and the connections between the wallboard and the bottom

The involvement of autophagy and cytoskeletal regulation in TDCIPP-induced SH-SY5Y cell differentiation

Exposure and toxicity to organophosphate-based flame retardants are an increasing health concern. Neurons appear to be particularly vulnerable to the effects of these chemicals. For example, in vitro studies have shown that tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) induces apoptosis and autophagy in neural cells. In the present study, we investigated the cell biological mechanisms of TDCIPP-induced neurotoxicity using undifferentiated human SH-SY5Y neuroblastoma cells as a model. Interestingly, TDCIPP treatment promoted differentiation in SH-SY5Y cells, which displayed various alterations including neurite elongation, an expansion of the numbers of neurite-bearing cells, and an increase in expression of cytoskeletal components normally enriched in neurons. Furthermore, the upregulation of microtubule-associated protein light chain 3, the degradation of p62/sequestosome 1, and the formation of autophagosomes occurred in treated cells, suggesting that TDCIPP exposure induces autophagy. However, pretreatment with the autophagy inhibitor 3-methyladenine suppressed TDCIPP-induced autophagy and reduced expression of the aforementioned cytoskeletal components. This correlated with a reduction in neurite outgrowth and numbers of neurite-bearing cells. Taken together, these results indicate that autophagy might promote TDCIPP-induced SH-SY5Y cell differentiation, which leads to an increase in expression of cytoskeletal components and neurite outgrowth. This study offers key insights into the mechanisms of neurotoxicity associated with this commonly used organophosphate. (C) 2017 Published by Elsevier B.V.</p

Tris (1, 3-dichloro-2-propyl) phosphate induces apoptosis and autophagy in SH-SY5Y cells: Involvement of ROS-mediated AMPK/mTOR/ULK1 pathways

Tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP), an extensively used organophosphorus flame retardant, is frequently detected in the environment and biota. Recent studies have shown that TDCIPP has neurotoxic effects. We hypothesized that the neurotoxicity might occur via the induction of the apoptosis and autophagy pathways. In the present study, we investigated TDCIPP-induced apoptotic death and autophagy in SH-SY5Y cells. Treatment with TDCIPP induced increased reactive oxygen species (ROS) generation and cell apoptosis, as well as autophagy. The autophagy inhibitor 3-methyladenine (3-MA) markedly decreased the expression of the autophagy marker beclin-1, microtubule-associated protein light chain 3-II (LC310, p62/sequestosome 1 (SQSTM1) degradation, and promoted apoptosis. Conversely, the autophagy inducer rapamycin (Rapa) alleviated TDCIPP-induced apoptosis and markedly increased the expression of the autophagy markers. Pretreatment with N-acetyl cysteine (NAC) eliminated the increased ROS generation, resulting in increased cell viability. For further examination of the signaling pathways involved in TDCIPP-induced autophagy, compound C, a pharmacological inhibitor of adenosine monophosphate activated protein kinase (AMPK) was used. Western blotting showed that compound C markedly reduced the expression of phospho-AMPK (p-AMPK) and phospho Unc-51-like kinase 1 (p-ULK1), increased phospho mammalian target of rapamycin (p-mTOR) expression, and decreased beclin-1 and LC3II expression. These results suggested that the AMPK/mTOR/ULK1 signaling pathway was involved in TDCIPP-induced autophagy. The antioxidant NAC antagonized TDCIPP-induced activation of AMPK and autophagy. Taken together, our findings provide the first evidence that TDCIPP promotes apoptosis and autophagy simultaneously and that this process involves the ROS-mediated AlVIPK/mTOR/ULK1 pathways. Lastly, the induction of autophagy is a protective mechanism against TDCIPP-induced apoptosis. (C) 2016 Published by Elsevier Ltd.</p

Tris (1,3-dichloro-2-propyl) phosphate -induced apoptotic signaling pathways in SH-SY5Y neuroblastoma cells

Tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP, also known as TDCPP), an extensively used flame retardant, is frequently detected in the environment and biota. Recent studies have shown that TDCIPP has neurotoxic effects. In this study, we determined the mechanisms of TDCIPP-induced neurotoxicity in human neuroblastoma (SH-SY5Y) cells. By using morphological examination, flow cytometry, and mitochondrial membrane potential (Delta Ym) measurement, we confirmed that exposure to TDCIPP caused apoptosis accompanied by the activation of apoptosis-related genes (e.g. Bax and Bc1-2) and caspase 3 protein in SH-SY5Y cells. Increased reactive oxygen species (ROS) formation and intracellular calcium ions ([Ca2+](i)) were also observed in TDCIPP-treated SH-SY5Y cells. Exposure to TDCIPP led to the activation of protein markers of endoplasmic reticulum (ER) stress, including eukaryotic translation initiation factor 2a subunit (p-EIF2a), activation transcription factor (ATF4), glucose-regulated protein (GRP78), and the proapoptotic factor C/EBP homologous protein (CHOP). To determine the role of the ER in apoptosis, phenyl butyric acid (PBA), an ER stress inhibitor, was applied. Treatment with PBA effectively attenuated TDCIPP-induced ER stress and protected against apoptotic death in SH-SY5Y cells by inhibition of Bax expression and promotion of Bcl-2 expression. Furthermore, we found that pretreatment of the cells with the ROS scavenger N-acetyl cysteine (NAC) inhibited the ER stress response and prevented apoptosis. The combination of PBA and NAC pretreatment could further prevent TDCIPP induced ER-stress and apoptotic death compared with PBA or NAC pretreatment alone. Thus, in the present study, we demonstrated that TDCIPP induces cytotoxicity through a ROS-dependent mechanism involving ER stress and activation of mitochondrial apoptotic pathways in SH-SY5Y cells. (C) 2016 Elsevier B.V. All rights reserved.</p

Special Issue: Advanced Science and Technology of Polymer Matrix Nanomaterials

Polymer matrix nanomaterials have revolutionized materials science due to their unique properties resulting from the incorporation of nanoscale fillers into polymer matrices [...

The attitude adjustment algorithm in drilling end-effector for aviation

To ensure the perpendicularity of drilling holes in aircraft manufacturing, the attitude of spindle axis must be adjusted to coincide with the normal vector of drilling point before drilling. The double eccentric discs-spherical pair structure was used as attitude adjustment mechanism in drilling end-effector. Therefore, the attitude adjustment algorithm of spindle axis is proposed in this article. There were two attitudes for current and target position, respectively, and the rotation sequence of each eccentric disc would affect the attitude adjustment efficiency. This article presents the path planning and optimal solution choosing from multiple solutions. Finally, the effectiveness and accuracy of the algorithm are verified in simulation and drilling experiment, resulting in a normality tolerance of ±0.5° and precision of H9

Recent Advances of Solution-Processed Heterojunction Oxide Thin-Film Transistors

Thin-film transistors (TFTs) made of metal oxide semiconductors are now increasingly used in flat-panel displays. Metal oxides are mainly fabricated via vacuum-based technologies, but solution approaches are of great interest due to the advantages of low-cost and high-throughput manufacturing. Unfortunately, solution-processed oxide TFTs suffer from relatively poor electrical performance, hindering further development. Recent studies suggest that this issue could be solved by introducing a novel heterojunction strategy. This article reviews the recent advances in solution-processed heterojunction oxide TFTs, with a specific focus on the latest developments over the past five years. Two of the most prominent advantages of heterostructure oxide TFTs are discussed, namely electrical-property modulation and mobility enhancement by forming 2D electron gas. It is expected that this review will manifest the strong potential of solution-based heterojunction oxide TFTs towards high performance and large-scale electronics

Fast Response Solar-Blind Photodetector with a Quasi-Zener Tunneling Effect Based on Amorphous In-Doped Ga2O3 Thin Films

A high-performance solar-blind photodetector with a metal&ndash;semiconductor&ndash;metal structure was fabricated based on amorphous In-doped Ga2O3 thin films prepared at room temperature by radio frequency magnetron sputtering. The photodetector shows a high responsivity (18.06 A/W) at 235 nm with a fast rise time (4.9 &mu;s) and a rapid decay time (230 &mu;s). The detection range was broadened compared with an individual Ga2O3 photodetector because of In doping. In addition, the uneven In distribution at different areas in the film results in different resistances, which causes a quasi-Zener tunneling internal gain mechanism. The quasi-Zener tunneling internal gain mechanism has a positive impact on the fast response speed and high responsivity