410 research outputs found

    Similarities and differences in interaction of K(+) and Na(+) with condensed ordered DNA. A molecular dynamics computer simulation study

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    Four 20 ns molecular dynamics simulations have been performed with two counterions, K(+) or Na(+), at two water contents, 15 or 20 H(2)O per nucleotide. A hexagonal simulation cell comprised of three identical DNA decamers [d(5′-ATGCAGTCAG) × d(5′-TGACTGCATC)] with periodic boundary condition along the DNA helix was used. The simulation setup mimics the DNA state in oriented DNA fibers or in crystals of DNA oligomers. Variation of counterion nature and water content do not alter averaged DNA structure. K(+) and Na(+) binding to DNA are different. K(+) binds to the electronegative sites of DNA bases in the major and the minor grooves, while Na(+) interacts preferentially with the phosphate groups. Increase of water causes a shift of both K(+) and Na(+) from the first hydration shell of O1P/O2P and of the DNA bases in the minor groove with lesser influence for the cation binding to the bases in the major groove. Mobility of both water and cations in the K–DNA systems is faster than in the Na–DNA systems: Na(+) organizes and immobilizes water structure around itself and near DNA while for K(+) water is less organized and more dynamic

    A Flexible Endoscopic Machining Tool

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    AbstractFlexible endoscopic tools are considerably applied in industrial image based inspecting operations, but none of them are currently effective enough to carry out machining tasks, such as grinding. If machining and inspection can be done in a single step, significant amount of labor force, money and energy can be saved in industrial repairing and maintenance tasks. This paper proposed a concept design of novel endoscopic machining tool, which aims at quantitatively and precisely removing material from imperfect components in hard-to-reach cavities, such as turbine blades in a jet engine. Prediction models are built to estimate the pose, force and material removal rate (MRR) of a modified PENTAX ES-3801 endoscope. Preliminary experimental results show that in two-dimensional (2D) grinding configuration the MRR average error of 22% has been achieved for 18 samples tested. In the end, concept designs of self-stabilized endoscopic grinding tool are proposed and discussed

    A Unified Power Control Method for Standalone and Grid Connected DFIG-DC System

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    The Construction of a Clinical Decision Support System Based on Knowledge Base

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    Part 7: e-Health, the New Frontier of Service Science InnovationInternational audienceBased on a review of domestic and foreign research, application status, classification, composition, and the main problem of a clinical decision support system, this paper proposed a CDSS mode based on a knowledge base. On KB-CDSS mode, this paper discussed the architecture, principle, process, construction of the knowledge base, system design, and application value, then introduced the application WanFang Data Clinical Diagnosis and Treatment Knowledge Base

    Eleutheroside E inhibits doxorubicin-induced inflammation and apoptosis in rat cardiomyocytes by modulating activation of NF-κB pathway

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    Purpose: To identify the effects of eleutheroside E (EE) on apoptosis and   inflammation induced by doxorubicin (DOX) in H9c2 cells and to investigate the underlying mechanisms.Methods: The effect of EE on H9c2 cell viability was determined using Cell Counting Kit-8 (CCK8). EE effect on DOX-induced apoptosis and inflammation in H9c2 cells was studied by comparison between cells treated with DOX alone and DOX+EE; the relationship between EE effects and NF-κB signaling pathway was evaluated by the addition of NF-κB inhibitor PDTC. Cell apoptosis was examined by flow cytometry while IL-1β, IL-6, and TNF-α levels were determined by ELISA. The phosphorylation level of NF-κB p65 was measured by Western blot.Results: Compared with control group, cell viability was notably elevated after  treatment with 50-100 μM EE for 48 or 72 h. DOX induced higher rates of cell  apoptosis in H9c2 cells (29.5 ± 3.56 %) compared with control group (6.39 ± 0.67 %); however, with EE pretreatment (50 and 80 μM), apoptosis rate decreased to 16.8 ± 2.16 and 13.54 ± 2.08 %, respectively, which are significantly lower than that of DOX group; furthermore, the levels of IL-1β, IL-6, and TNF-α also reduced. In addition, DOX-induced phosphorylation of NF-κB p65 was suppressed by EE pretreatment (10, 50 and 80 μM) to 11.51 ± 1.25, 40.2 ± 5.17 and 52.97 ± 6.74 %, respectivelyConclusion: The results suggest that EE treatment reduced DOX-induced apoptosis and inflammation by interacting with NF-κB signaling pathway. This finding sheds some light on probable new strategies on the application of DOX for cancer treatment.Keywords: Eleutheroside E, Doxorubicin, Inflammation, Apoptosis, Cardiomyocytes, NF-κ

    Design of an Automatic Defect Identification Method Based ECPT for Pneumatic Pressure Equipment

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    In this paper, in order to achieve automatic defect identification for pneumatic pressure equipment, an improved feature extraction algorithm eddy current pulsed thermography (ECPT) is presented. The presented feature extraction algorithm contains four elements: data block selection; variable step search; relation value classification; and between-class distance decision function. The data block selection and variable step search are integrated to decrease the redundant computations in the automatic defect identification. The goal of the classification and between-class distance calculation is to select the typical features of thermographic sequence. The main image information can be extracted by the method precisely and efficiently. Experimental results are provided to demonstrate the capabilities and benefits (i.e., reducing the processing time) of the proposed algorithm in automatic defect identification

    MoS2/Au-Sensitized TiO2 Nanotube Arrays with Core-Shell Nanostructure for Hydrogen Production

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    Herein, a TiO2 NTAs-Au-MoS2 core–shell photoanode was constructed with the intention to fulfill the efficient transfer of photo-generated carriers to the photoelectrode’s surface. Au nanoparticles were decorated by a drop casting method, and the MoS2 layer was deposited above the Au nanoparticles using a photoreduction-annealing process. Au nanoparticles were well dispersed on the inner wall of the TiO2 nanotubes and covered by the MoS2 layer, forming a core–shell nanostructure. The MoS2 layer significantly improved the attachment between Au nanoparticles and TiO2 NTAs, resulting in increased PEC stability and performance. Attributed to the excitation of Au nanoparticles’ localized surface plasmon resonance effect and visible light utilization of MoS2, the TiO2 NTAs-Au-MoS2 core–shell photoanode exhibits greatly enhanced photocurrent density. An increase from 67[Formula: see text][Formula: see text]A/cm2 to 234[Formula: see text][Formula: see text]A/cm2 under Xe lamp illumination and from 2.6[Formula: see text][Formula: see text]A/cm2 to 12.6[Formula: see text][Formula: see text]A/cm2 under visible light illumination ([Formula: see text][Formula: see text]nm) compared with the TiO2 NTAs was observed. </jats:p
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