8,296 research outputs found

    Proline-rich tyrosine kinase 2 mediates gonadotropin-releasing hormone signaling to a specific extracellularly regulated kinase-sensitive transcriptional locus in the luteinizing hormone beta-subunit gene

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    G protein-coupled receptor regulation of gene transcription primarily occurs through the phosphorylation of transcription factors by MAPKs. This requires transduction of an activating signal via scaffold proteins that can ultimately determine the outcome by binding signaling kinases and adapter proteins with effects on the target transcription factor and locus of activation. By investigating these mechanisms, we have elucidated how pituitary gonadotrope cells decode an input GnRH signal into coherent transcriptional output from the LH beta-subunit gene promoter. We show that GnRH activates c-Src and multiple members of the MAPK family, c-Jun NH2-terminal kinase 1/2, p38MAPK, and ERK1/2. Using dominant-negative point mutations and chemical inhibitors, we identified that calcium-dependent proline-rich tyrosine kinase 2 specifically acts as a scaffold for a focal adhesion/cytoskeleton-dependent complex comprised of c-Src, Grb2, and mSos that translocates an ERK-activating signal to the nucleus. The locus of action of ERK was specifically mapped to early growth response-1 (Egr-1) DNA binding sites within the LH beta-subunit gene proximal promoter, which was also activated by p38MAPK, but not c-Jun NH2-terminal kinase 1/2. Egr-1 was confirmed as the transcription factor target of ERK and p38MAPK by blockade of protein expression, transcriptional activity, and DNA binding. We have identified a novel GnRH-activated proline-rich tyrosine kinase 2-dependent ERK-mediated signal transduction pathway that specifically regulates Egr-1 activation of the LH beta-subunit proximal gene promoter, and thus provide insight into the molecular mechanisms required for differential regulation of gonadotropin gene expression

    Synthesis and Applications of Dicationic Iodide Materials for Dye-Sensitized Solar Cells

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    Dye-sensitized solar cells (DSSCs) have been receiving growing attentions as a potential alternative to order photovoltaic devices due to their high efficiency and low manufacturing cost. DSSCs are composed of a photosensitizing dye adsorbed on a mesoporous film of nanocrystalline TiO2 as a photoelectrode, an electrolyte containing triiodide/iodide redox couple, and a platinized counter electrode. To improve photovoltaic properties of DSSCs, new dicationic salts based on ionic liquids were synthesized. Quite comparable efficiencies were obtained from electrolytes with new dicationic iodide salts. The best cell performance of 7.96% was obtained with dicationic salt of PBDMIDI

    Integration of Gold Nanoparticle-Carbon Nanotube Composite for Enhanced Contact Lifetime of Microelectromechanical Switches with Very Low Contact Resistance

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    Electrical circuits require ideal switches with low power consumption for future electronic applications. However, transistors, the most developed electrical switches available currently, have certain fundamental limitations such as increased leakage current and limited subthreshold swing. To overcome these limitations, micromechanical switches have been extensively studied; however, it is challenging to develop micromechanical switches with high endurance and low contact resistance. This study demonstrates highly reliable microelectromechanical switches using nanocomposites. Nanocomposites consisting of gold nanoparticles (Au NPs) and carbon nanotubes (CNTs) are coated on contact electrodes as contact surfaces through a scalable and solution-based fabrication process. While deformable CNTs in the nanocomposite increase the effective contact area under mechanical loads, highly conductive Au NPs provide current paths with low contact resistance between CNTs. Given these advantages, the switches exhibit robust switching operations over 5 x 10(6) cycles under hot-switching conditions in air. The switches also show low contact resistance without subthreshold region, an extremely small leakage current, and a high on/off ratio.

    author

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    authorIn other places [Old Joe, the trapper] pointed out otter (or, as he pronounced it, "author") slidesPRINTED ITEM G.M.Story April 1959Not UsedNot UsedWithdrawn[see 'otter']Checked by Jordyn Hughes on Thu 09 Jun 201

    Semi-empirical model for abrasive particle velocity prediction in abrasive waterjet based on momentum transfer efficiency

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    Abrasive waterjet (AWJ) is a technology that removes a target material with an abrasive accelerated by ultra-high-pressure water. Recently, its application for rock excavations in civil and geotechnical engineering has increased. AWJ excavation performance is affected by the abrasive velocity formed by momentum transfer during mixing and acceleration. The abrasive velocity varies owing to changes in the abrasive flow rate, focusing tube diameter, and focusing tube length. In this study, the momentum transfer efficiency (MTE) according to the abrasive flow rate and focusing tube geometry was investigated by a numerical analysis to better understand the multiphase flow inside the AWJ system. The MTE was defined based on the theoretical relationship between the abrasive velocity ratio and focusing tube factor, and evaluated through the empirical relationship between the water stiffness and focusing tube length. The optimal abrasive flow rate for generating efficient MTE was approximately 15 g/s, which enabled economical and effective acceleration of abrasive particles. Accordingly, a prediction model based on the derived MTE was developed for the final abrasive velocity generated at the tip of the focusing tube. Using the prediction model, it is possible to evaluate the comprehensive relationship between various AWJ parameters. Based on the prediction model, the abrasive-water flow ratio to generate the optimal abrasive velocity was 0.83. The developed prediction model provides guidelines for selecting the optimal focusing tube geometry and applying an economical abrasive flow rate when designing an AWJ system.

    Jia ru ju he wu dui jun yun tuan liu ji jun yun tuan liu dui liu de ying xiang

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    Wong, Chai Kwok = 加入聚合物對均勻湍流及均勻湍流對流的影響 / 黃濟國.Thesis M.Phil. Chinese University of Hong Kong 2013.Includes bibliographical references (leaves 89-91).Abstracts also in Chinese.Title from PDF title page (viewed on 01, November, 2016).Wong, Chai Kwok = Jia ru ju he wu dui jun yun tuan liu ji jun yun tuan liu dui liu de ying xiang / Huang Jiguo

    Author Correction: Manipulating anion intercalation enables a high-voltage aqueous dual ion battery

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    The original version of this Article did not acknowledge Prof. Jun Fan as a corresponding author. This has now been corrected in both the PDF and HTML versions of the Article.link_to_subscribed_fulltex

    Corrigendum: The taeniaticornis-group of genus Apanteles Foerster (Hymenoptera, Braconidae, Microgastrinae) from China with one new species. Journal of Hymenoptera Research 96: 21–31. doi: 10.3897/jhr.96.99649

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    In a paper about a new species of Apanteles (Microgastrinae)(Liu & Chen, 2023), we regret the omission of one author Jun-hua Chen in the second place of the author list who did great job in construction of the ZJUH collection for this study and the mistake in institution order and corresponding author. We provide the correct information below.Zhen Liu1, 2, Jun-hua He1, Xue-xin Chen11 Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China. 2 Zoology Key Laboratory of Hunan Higher Education, College of Life and Environmental Sciences, Hunan University of Arts and Science, Changde 415000, China
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