20 research outputs found

    Ethanol Extract of the Infructescence of Platycarya strobilacea Sieb. et Zucc. Induces Methuosis of Human Nasopharyngeal Carcinoma Cells

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    The infructescence of Platycarya strobilacea Sieb. et Zucc. (PS) has been used in the treatment of rhinitis and sinusitis in clinical practice. Our preliminary study showed that an ethanol extract of the infructescence of PS (EPS) had significant antinasopharyngeal carcinoma (NPC) effects in vitro. However, the mechanism underlying the NPS cell death induced by EPS remains unclear. The aim of the present study was to investigate the inhibitory effects of EPS on NPC cells and to elucidate the underlying mechanism. The effects of EPS on NPC cells were investigated in CNE1 and CNE2 cells in vitro. In EPS-treated cells, the cell morphological changes were evaluated through fluorescence microscope, transmission electron microscopy, and flow cytometry. The underlying mechanism was analyzed via network pharmacology and further verified by western blot analysis. The anticancer effects of EPS were associated with the generation of CNE1 and CNE2 cell fusion and vacuoles, the perturbation of lysosomal vesicle transportation, and the induction of methuosis. The network pharmacology and western blot results indicated that the effect of EPS in NPC cells might be achieved via regulation of the Ras proto-oncogene (RAS)/mitogen-activated protein kinase (MAPK) signaling pathway and the transcription factor c-Fos proto-oncogene (c-FOS) and its downstream genes. EPS induces NPC cell death through methuosis. The mechanism might be related to regulation of the transcription factor c-FOS and its downstream genes

    Neuroprotection Effect of Astragaloside IV from 2-DG-Induced Endoplasmic Reticulum Stress

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    Objective. Astragaloside IV shows neuroprotective activity, but its mechanism remains unclear. To investigate whether astragaloside IV protects from endoplasmic reticulum stress (ERS), we focus on the regulation of glycogen synthase kinase-3β (GSK-3β) and mitochondrial permeability transition pore (mPTP) by astragaloside IV in neuronal cell PC12. Methods and Results. PC12 cells treated with different concentrations of ERS inductor 2-deoxyglucose (2-DG) (25-500 μM) showed a significant increase of glucose-regulated protein 78 (GRP 78) and GRP 94 expressions and a decrease of tetramethylrhodamine ethyl ester (TMRE) fluorescence intensity and mitochondrial membrane potential (∆Ψm), with the peak effect seen at 50 μM, indicating that 2-DG induces ERS and the mPTP opening. Similarly, 50 μM of astragaloside IV increased the GSK-3β phosphorylation at Ser9 most significantly. Next, we examined the neuroprotection of astragaloside IV by dividing the PC12 cells into control group, 2-DG treatment group, astragaloside IV plus 2-DG treatment group, and astragaloside IV only group. PC12 cells treated with 50 μM 2-DG for different time courses (0-36 hr) showed a significant increase of Cleaved-Caspase-3 with the peak at 6 hr. 2-DG significantly induced cell apoptosis and increased the green fluorescence intensity of Annexin V-FITC, and these effects were reversed by astragaloside IV. Such a result indicates that astragaloside IV protected neural cell survival from ERS. 2-DG treatment significantly increased the expressions of inositol-requiring ER-to-nucleus signal kinase 1 (IRE1), phosphor-protein kinase R-like ER kinase (p-PERK), but not affect the transcription factor 6 (ATF6) expression. 2-DG treatment significantly decreased the phosphorylation of GSK-3β and significantly reduced the TMRE fluorescence intensity and ∆Ψm, following mPTP open. Astragaloside IV significantly inhibited the above effects caused by 2-DG, except the upregulation of ATF6 protein. Taken together, astragaloside IV significantly inhibited the ERS caused by 2-DG. Conclusion. Our data suggested that astragaloside IV protects PC12 cells from ERS by inactivation of GSK-3β and preventing the mPTP opening. The GRP 78, GRP 94, IRE1, and PERK signaling pathways but not ATF6 are responsible for GSK-3β inactivation and neuroprotection by astragaloside IV

    Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

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    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 A degrees C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (< 2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 +/- A 0.8 nm size were formed by using Bacillus megatherium D01.National Natural Science Foundation of China [20433040, 20423002]; State Key Laboratory for Physical Chemistry of the Solid Surface, Xiamen University of China [200408

    A Potential Density Gradient Dependent Analysis Scheme for Ocean Multiscale Data Assimilation

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    This study addresses how to maintain oceanic mixing along potential density surface in ocean data assimilation (ODA). It is well known that the oceanic mixing across the potential density surface is much weaker than that along the potential density surface. However, traditional ODA schemes allow the mixing across the potential density surface and thus may result in extra assimilation errors. Here, a new ODA scheme that uses potential density gradient information of the model background to rescale observational adjustment is designed to improve the quality of assimilation. The new scheme has been tested using a regional ocean model within a multiscale 3-dimensional variational framework. Results show that the new scheme effectively prevents the excessive unphysical projection of observational information in the direction across potential density surface and thus improves assimilation quality greatly. Forecast experiments also show that the new scheme significantly improves the model forecast skills through providing more dynamically consistent initial condition

    Preparation and anti-triple-negative breast cancer cell effect of a nanoparticle for the codelivery of paclitaxel and gemcitabine

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    Abstract Amphiphilic polymers (HA-ANI) were prepared by grafting hyaluronic acid (HA) and 6-(2-nitroimidazole)hexylamine (ANI) and then self-assemble in water to form nanoparticles (NPs) that could be loaded with paclitaxel (PTX) and gemcitabine (GEM) by dialysis. Infrared spectroscopy and 1H-NMR indicated the successful synthesis of HA-ANI. Three different ratios of NPs were prepared by adjusting the ratios of hydrophilic and hydrophobic materials, and the particle size decreased as the ratio of hydrophilic materials increased. When HA:ANI = 2.0:1, the nanoparticles had the smallest size distribution, good stability and near spherical shape and had high drug loading and encapsulation rates. In vitro release experiments revealed that NADPH could accelerate the drug release from NPs. Cellular uptake rate reached 86.50% at 6 h. The toxic effect of dual drug-loaded nanoparticles (P/G NPs) on MDA-MB-231 cells at 48 h was stronger than that of the free drug. The AO/EB double-staining assay revealed that a large number of late apoptotic cells appeared in the P/G NPs group, and the degree of cell damage was significantly stronger than that of the free drug group. In the cell migration assay, the 24 h-cell migration rate of the P/G NPs group was 5.99%, which was much lower than that of the free group (13.87% and 17.00%). In conclusion, MDA-MB-231 cells could effectively take up P/G NPs, while the introduction of the nano-codelivery system could significantly enhance the toxicity of the drug to MDA-MB-231 cells as well as the migration inhibition effect

    Modulation Format Identification Based on Signal Constellation Diagrams and Support Vector Machine

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    In coherent optical communication systems, where multiple modulation formats are mixed and variable, the correct identification of signal modulation formats provides the foundation for subsequent performance improvement using digital algorithms. A modulation format identification (MFI) scheme based on signal constellation diagrams and support vector machine (SVM) is proposed. Firstly, the signal constellation diagrams are divided by the fractal dimension of the weighted linear least squares (WLS-FD) algorithm, and the fractal dimension (FD) in each region is calculated, which is regarded as one of the image features. Then, the feature values of the image in different directions are extracted by the gray-level co-occurrence matrix (GLCM), and their mean and variance are calculated, which is regarded as another feature. Finally, the two features are input into the modulation format classifier constructed by the SVM to achieve MFI in coherent optical communication systems. To verify the feasibility and superiority of the scheme, we compare it with the MFI scheme based on higher-order statistical (HOS) features, GLCM features, and FD features, respectively. Further, we built a 30 GBaud coherent optical communication system with fiber lengths of 80 km and 120 km, where the optical signal-to-noise ratio (OSNR) ranges from 0 dB to 30 dB. The proposed MFI scheme identifies seven modulation formats: QPSK, 8QAM, 16QAM, 32QAM, 64QAM, 128QAM, and 256QAM. The results show that compared with the other three schemes, our proposed scheme has a better identification accuracy at low OSNR. In addition, the identification accuracy of this scheme can reach 100% when the OSNR ≥ 10 dB

    Electrochemical Determination of Trace Amouns of Gold(Ⅲ)by Cathodic Sptripping Voltammetry Using a Carborn Paste Electroele Modified with Bacteria

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    研究用细菌修饰的碳糊电极对金离子的响应特性,并应用该电极检测水溶液中的金离子,金离子浓度在10~100μg/mL.呈线性关系,重现性为3.4%,检测限达1ng/mL.电极具有制备简单,灵敏度高等优点.文中还讨论了金离子在还原菌修饰的碳糊电极上的还原机理.An electrochemically pretreated carbon paste electrode modified with bacteria has been studied and used for determination of trace amounts of gold(Ⅲ). A detection limit of 1 ng/mL was obtained by applying cathodic stripping valtammetry. There is a linear relationship between the concentration and peak height in the range of 10~100 μg/mL. The ralative standard deviation of the response to 84.7 μg/mL Au(Ⅲ) is 3.43%.作者联系地址:厦门大学化学系固体表面物理化学国家重点实验室国家教委材料和生命过程分析科学开放研究实验室Author's Address: State Key Lab. for Phys. Chem. of Solid Surf., Depet. of Chem., Xiamen Univ., Xiamen 36100

    Modulation Format Identification Based on Signal Constellation Diagrams and Support Vector Machine

    No full text
    In coherent optical communication systems, where multiple modulation formats are mixed and variable, the correct identification of signal modulation formats provides the foundation for subsequent performance improvement using digital algorithms. A modulation format identification (MFI) scheme based on signal constellation diagrams and support vector machine (SVM) is proposed. Firstly, the signal constellation diagrams are divided by the fractal dimension of the weighted linear least squares (WLS-FD) algorithm, and the fractal dimension (FD) in each region is calculated, which is regarded as one of the image features. Then, the feature values of the image in different directions are extracted by the gray-level co-occurrence matrix (GLCM), and their mean and variance are calculated, which is regarded as another feature. Finally, the two features are input into the modulation format classifier constructed by the SVM to achieve MFI in coherent optical communication systems. To verify the feasibility and superiority of the scheme, we compare it with the MFI scheme based on higher-order statistical (HOS) features, GLCM features, and FD features, respectively. Further, we built a 30 GBaud coherent optical communication system with fiber lengths of 80 km and 120 km, where the optical signal-to-noise ratio (OSNR) ranges from 0 dB to 30 dB. The proposed MFI scheme identifies seven modulation formats: QPSK, 8QAM, 16QAM, 32QAM, 64QAM, 128QAM, and 256QAM. The results show that compared with the other three schemes, our proposed scheme has a better identification accuracy at low OSNR. In addition, the identification accuracy of this scheme can reach 100% when the OSNR &ge; 10 dB

    A Novel 64 QAM-OFDM Optical Access System Based on Bit Reconstruction

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    This paper proposes a novel orthogonal frequency division multiplexing (OFDM) optical access scheme based on bit reconstruction. In this method, correlation is introduced into the data information of optical line terminals (OLT) through the logical coding circuits and partition mapping. Even after passing through the optical fibre channel, the strong correlation after bit reconstruction can still be used in the optical network unit (ONU) for reliable decoding. In the simulation experiments, a 60 Gbit/s bit reconstruction 64 quadrature amplitude modulation (QAM) OFDM signal was successfully transmitted over a 10/20 km single-mode fibre (SMF). The simulation results show that the proposed scheme can effectively achieve reliable transmission with gains of about 1.3 dB and 0.51 dB at a 20% soft decision-forward error correction (SD-FEC) threshold, respectively. The proposed scheme is a promising candidate for a next-generation passive optical network (NGPON) solution
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