382 research outputs found

    Indole-thiophene conjugate inhibits proliferation of human cervical cancer cell lines through DNA damage

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    Purpose: To investigate the inhibitory effect of indole-thiophene conjugate (ITC) against cervical cancer cells. Methods: The effect of ITC on the proliferation of cervical cells was determined using 3 (4,5 dimethylthiazol 2 yl) 2,5 diphenyltetrazolium bromide (MTT) assay. The apoptosis-inducing effect of ITC was analysed with flow cytometry, while its effect on cell invasion was assessed using Transwell assay. Results: ITC inhibited proliferation of HeLa and Caski cancer cell lines, but it had no cytotoxicity against HCvEpC normal epithelial cells. Exposure to ITC at a dose of 12 μmol/L reduced the viability of HeLa and Caski cells to 22.56 and 24.78 %, respectively (p < 0.05). ITC treatment of HeLa cells enhanced the proportion of apoptotic cells. Exposure to ITC at a dose of 12 μmol/L led to near-complete inhibition of the invasive potential of HeLa cells. Moreover, exposure of HeLa cells to ITC downregulated the protein expressions of MMP-2 and MMP-9 (p < 0.05). The expressions of Bcl-2, p-ERK1/2 and p-Akt were markedly decreased in HeLa cells by ITC exposure. In addition, ITC increased Bax expression, and decreased Bcl-2/Bax ratio (p < 0.05). Conclusion: ICT inhibits the proliferation and invasion of cervical cancer cells, and induces their apoptosis. It exhibits these effects via the suppression of Akt and ERK phosphorylation, thereby downregulating the PI3K and MAPK pathways. Therefore, ITC may be beneficial for the treatment of cervical cancer

    Numerical analysis on magnetic leakage field of pipeline defect

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    Pipeline magnetic flux leakage inspection, mainly used for pipeline defect detection, is an important means of inner examination technology on pipeline. Flux leakage testing can't obtain valid defect identification signals by one hundred percent because of magnetization of the magnetic leakage field, the measured shape, size and location of pipeline defects, materials and operating conditions, and lift-off value, pole pitch and the length of steel brush during the measurement as well as forged pipe fittings such as welding seam, stiffener, flange and tee on the pipeline to be tested. This article reaches a conclusion that magnetic flux density distribution is influenced by the depth and width of defect through respectively researching magnetic leakage field of individual defect and double defects (thickness type) by finite-element method. It also conducts the numerical analysis on pipeline welding seam, stiffener, flange (increased wall thickness type) and tee (compound) leakage magnetic field in detection conditions of the same direction, and concludes their distribution rules of magnetic flux density. The characteristic parameters of distinguishing defect magnetic flux leakage field and the part of the pipeline magnetic flux leakage, derived from analysis and comparison of results on defective pipeline and conduit joint, stiffener, flange and tee magnetic flux leakage, provide a foundation of qualitative identification for accurately recognizing pipeline defect and eliminating the impact of other ancillary fittings on a pipe on pipeline magnetic flux leakage, and they can also offer infallible data to pipeline maintenance as a basis of quantitative analysis

    Numerical investigation of the energy performance of a guideless irregular heat and mass exchanger with corrugated heat transfer surface for dew point cooling

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    © 2016 The Author(s) The paper presents an investigation into the energy performance of a novel irregular heat and mass exchanger for dew point cooling which, compared to the existing flat-plate heat exchangers, removed the use of the channel supporting guides and implemented the corrugated heat transfer surface, thus expecting to achieve the reduced air flow resistance, increased heat transfer area, and improved energy efficiency (i.e. Coefficient of Performance (COP)) of the air cooling process. CFD simulation was carried out to determine the flow resistance (K) factors of various elements within the dry and wet channels of the exchanger, while the ‘finite-element’ based ‘Newton-iteration’ numerical simulation was undertaken to investigate its cooling capacity, cooling effectiveness and COP at various geometrical and operational conditions. Compared to the existing flat-plate heat and mass exchangers with the same geometrical dimensions and operational conditions, the new irregular exchanger could achieve 32.9%–37% higher cooling capacity, dew-point and wet-bulb effectiveness, 29.7%–33.3% higher COP, and 55.8%–56.2% lower pressure drop. While undertaking dew point air cooling, the irregular heat and mass exchanger had the optimum air velocity of 1 m/s within the flow channels and working-to-intake air ratio of 0.3, which allowed the highest cooling capacity and COP to be achieved. In terms of the exchanger dimensions, the optimum height of the channel was 5 mm while its length was in the range 1–2 m. Overall, the proposed irregular heat and mass exchanger could lead to significant enhanced energy performance compared to the existing flat-plate dew point cooling heat exchanger of the same geometrical dimensions. To achieve the same amount cooling output, the irregular heat and mass exchanger had the reduced size and cost against the flat-plate ones

    Shear slitting of aluminum webs using block knives

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    C Shear slitting of two aluminum webs, namely 1050 H18 of 0.28 mm thick and 5182 H19 of 0.20 mm thick, using block knives are investigated through experiments using a laboratory slitter. This investigation focused on two aspects of shear slitting using block knives, appropriate for relatively thick webs. They are: (1) tangential shear slitting at zero rake angle, i.e., traditional shear slitting with a pair of block knives. In this aspect, the effects of major slitting parameters on the burr height at the slit edge were investigated. These include the clearance, overlap, overdrive and cant angle. The critical clearances for both webs have been determined; and (2) slitting at a rake angle, a new method for edge trimming when the two blades are not necessarily in contact. The top blade geometry was modified for slitting with a rake angle of -15o to allow slitting of an aluminum web, up to 1 mm thick in this investigation. This new method of edge trimming using block knives was found to be very effective and robust over a (relatively) very wide range of slitting parameters. Very good slit edge was produced, and the burr height was found to be independent of slitting parameters over a relatively large range of slitting parameters. Because two blades do not have to be in contact in slitting so that the blade wear is much less than in the case of traditional shear slitting, this new method is expected to extend significantly the block knife service life while producing consistently high quality slit edges.Mechanical and Aerospace Engineerin

    Photochemical reaction enabling the engineering of photonic spin-orbit coupling in organic-crystal optical microcavities

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    The control and active manipulation of spin-orbit coupling (SOC) in photonic systems is fundamental in the development of modern spin optics and topological photonic devices. Here, we demonstrate the control of an artificial Rashba-Dresselhaus (RD) SOC mediated by photochemical reactions in a microcavity filled with an organic single-crystal of photochromic phase-change character. Splitting of the circular polarization components of the optical modes induced by photonic RD SOC is observed experimentally in momentum space. By applying an ultraviolet light beam, we control the spatial molecular orientation through a photochemical reaction and with that we control the energies of the photonic modes. This way we realize a reversible conversion of spin-splitting of the optical modes with different energies, leading to an optically controlled switching between circularly and linearly polarized emission from our device. Our strategy of in situ and reversible engineering of SOC induced by a light field provides a promising approach to actively design and manipulate synthetic gauge fields towards future on-chip integration in photonics and topological photonic devices

    Pest-YOLO: A model for large-scale multi-class dense and tiny pest detection and counting

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    Frequent outbreaks of agricultural pests can reduce crop production severely and restrict agricultural production. Therefore, automatic monitoring and precise recognition of crop pests have a high practical value in the process of agricultural planting. In recent years, pest recognition and detection have been rapidly improved with the development of deep learning-based methods. Although certain progress has been made in the research on pest detection and identification technology based on deep learning, there are still many problems in the production application in a field environment. This work presents a pest detector for multi-category dense and tiny pests named the Pest-YOLO. First, the idea of focal loss is introduced into the loss function using weight distribution to improve the attention of hard samples. In this way, the problems of hard samples arose from the uneven distribution of pest populations in a dataset and low discrimination features of small pests are relieved. Next, a non-Intersection over Union bounding box selection and suppression algorithm, the confluence strategy, is used. The confluence strategy can eliminate the errors and omissions of pest detection caused by occlusion, adhesion and unlabeling among tiny dense pest individuals to the greatest extent. The proposed Pest-YOLO model is verified on a large-scale pest image dataset, the Pest24, which includes more than 20k images with over 190k pests labeled by agricultural experts and categorized into 24 classes. Experimental results show that the Pest-YOLO can obtain 69.59% for mAP and 77.71% for mRecall on the 24-class pest dataset, which is 5.32% and 28.12% higher than the benchmark model YOLOv4. Meanwhile, our proposed model is superior to other several state-of-the-art methods, including the SSD, RetinaNet, Faster RCNN, YOLOv3, YOLOv4, YOLOv5s, YOLOv5m, YOLOX, DETR, TOOD, YOLOv3-W, and AF-RCNN detectors. The code of the proposed algorithm is available at: https://github.com/chr-secrect/Pest-YOLO

    A room-temperature electrical-field-enhanced ultrafast switch in organic microcavity polariton condensates

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    Integrated electro-optical switches are essential as one of the fundamental elements in the development of modern optoelectronics. As an architecture for photonic systems, exciton polaritons, that are hybrid bosonic quasiparticles that possess unique properties derived from both excitons and photons, have shown much promise. For this system, we demonstrate a significant improvement of emitted intensity and condensation threshold by applying an electric field to a microcavity filled with an organic microbelt. Our theoretical investigations indicate that the electric field makes the excitons dipolar and induces an enhancement of the exciton-polariton interaction and of the polariton lifetime. Based on these electric field induced changes, a sub-nanosecond electrical-field-enhanced polariton condensate switch is realized at room temperature, providing the basis for developing an on-chip integrated photonic device in the strong light-matter coupling regime

    High mobility group box 1 promotes radioresistance in esophageal squamous cell carcinoma cell lines by modulating autophagy

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    Resistance to radiotherapy results in relapse and treatment failure in locally advanced esophageal squamous cell carcinoma (ESCC). High mobility group box 1 (HMGB1) is reported to be associated with the radioresistance in bladder and breast cancer. However, the role of HMGB1 in the radiotherapy response in ESCC has not been fully elucidated. Here, we investigated the role of HMGB1 to radioresistance in ESCC clinical samples and cell lines. We found that HMGB1 expression was associated with tumor recurrence after postoperative radiotherapy in locally advanced ESCC patients. HMGB1 knockdown in ESCC cells resulted in increased radiosensitivity both in vitro and in vivo. Autophagy level was found depressed in HMGB1 inhibition cells and activation of autophagy brought back cell's radioresistance. Our results demonstrate that HMGB1 activate autophagy and consequently promote radioresistance. HMGB1 may be used as a predictor of poor response to radiotherapy in ESCC patients. Our finding also highlights the importance of the utility of HMGB1 in ESCC radiosensitization.Peer reviewe
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