2,356 research outputs found

    A Fractal Model for the Maximum Droplet Diameter in Gas-Liquid Mist Flow

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    Distribution characteristics of liquid droplet size are described using the fractal theory for liquid droplet size distribution in gas-liquid mist flow. Thereby, the fractal expression of the maximum droplet diameter is derived. The fractal model for maximum droplet diameter is obtained based on the internal relationship between maximum droplet diameter and the droplet fractal dimension, which is obtained by analyzing the balance between total droplet surface energy and total gas turbulent kinetic energy. Fractal model predictions of maximum droplet diameter agree with the experimental data. Maximum droplet diameter and droplet fractal dimension are both found to be related to the superficial velocity of gas and liquid. Maximum droplet diameter decreases with an increase in gas superficial velocity but increases with an increase in liquid superficial velocity. Droplet fractal dimension increases with an increase in gas superficial velocity but decreases with an increase in liquid superficial velocity. These are all consistent with the physical facts

    Pressure Transient Analysis of Dual Fractal Reservoir

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    A dual fractal reservoir transient flow model was created by embedding a fracture system simulated by a tree-shaped fractal network into a matrix system simulated by fractal porous media. The dimensionless bottom hole pressure model was created using the Laplace transform and Stehfest numerical inversion methods. According to the model's solution, the bilogarithmic type curves of the dual fractal reservoirs are illustrated, and the influence of different fractal factors on pressure transient responses is discussed. This semianalytical model provides a practical and reliable method for empirical applications

    The effect of transforming growth factor-β1 on nasopharyngeal carcinoma cells: insensitive to cell growth but functional to TGF-β/Smad pathway

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    <p>Abstract</p> <p>Objectives</p> <p>This study explored the response of nasopharyngeal carcinoma cells to TGF-β1-induced growth suppression and investigated the roles of the TGF-β/Smad signaling pathway in nasopharyngeal carcinoma cells.</p> <p>Methods</p> <p>The cells of nasopharyngeal carcinoma cell line CNE2 were treated with TGF-β1. The growth responses of CNE2 cells were analyzed by MTT assay. The mRNA expression and protein subcellular localization of the TGF-β/Smad signaling components in the CNE2 were determined by real time RT-PCR and immunocytochemical analysis.</p> <p>Results</p> <p>We found that the growth of CNE2 cells was not suppressed by TGF-β1. The signaling proteins TβRII, Smad 7 were expressed normally, while Smad2, Smad3, and Smad4 increased significantly at the mRNA level. TGF-β type II receptor and Smad7 had no change compared to the normal nasopharyngeal epithelial cells. In addition, Smad2 was phosphorylated to pSmad2, and the activated pSmad2 translocated into the nucleus from the cytoplasm, while the inhibitory Smad-Smad7 translocated from the nucleus to the cytoplasm after TGF-β1 stimulation.</p> <p>Conclusion</p> <p>The results suggested that CNE2 cells are not sensitive to growth suppression by TGF-β1, but the TGF-β/Smad signaling transduction is functional. Further work is needed to address a more detailed spectrum of the TGF-β/Smad signaling pathway in CNE2 cells.</p

    The Role of Histone Acetyltransferases in Normal and Malignant Hematopoiesis

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    Histone or non-histone protein acetylation plays important roles in all kinds of cellular events, including the normal and abnormal development of blood cells, through changing the epigenetic status of chromatin and regulating non-histone protein’s function. Histone acetyltransferases (HATs), which are the enzymes responsible for the histone or non-histone protein acetylation, contain p300/CBP, MYST and GNAT family etc. HATs are not only the protein modifiers and epigenetic factors, but also the critical regulators of cell development and cancerogenesis. Here we will review the function of HATs such as p300/CBP, Tip60, MOZ/MORF and GCN5/PCAF in the normal hematopoiesis and the pathogenesis of hematological malignancies. The inhibitors that have been developed to target HATs will also be reviewed here. Understanding the roles of HATs in normal/malignant hematopoiesis and the underlying mechanism will provide the potential therapeutic targets for the hematological malignancies

    Discovery of the nest of the yellow jacket Vespula structor (Smith) (Hymenoptera, Vespidae) from China with description of its immature stages

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    Data on the nest structure, morphology of all stages and behaviour have contributed to the phylogenetic and taxonomic studies of social vespids. Two underground nests of Vespula structor (Hymenoptera, Vespidae, Vespinae) were discovered in China. For the first time, the morphology of all the stages, and the nests are described in detail and illustrated. It is additional evidence supporting the recent conclusion that synonymized Vespula gongshanensis with V. structor. The status of Vespula structor within both the genus Vespula and the vulgaris-group are briefly discussed

    Beimingwu: A Learnware Dock System

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    The learnware paradigm proposed by Zhou [2016] aims to enable users to reuse numerous existing well-trained models instead of building machine learning models from scratch, with the hope of solving new user tasks even beyond models' original purposes. In this paradigm, developers worldwide can submit their high-performing models spontaneously to the learnware dock system (formerly known as learnware market) without revealing their training data. Once the dock system accepts the model, it assigns a specification and accommodates the model. This specification allows the model to be adequately identified and assembled to reuse according to future users' needs, even if they have no prior knowledge of the model. This paradigm greatly differs from the current big model direction and it is expected that a learnware dock system housing millions or more high-performing models could offer excellent capabilities for both planned tasks where big models are applicable; and unplanned, specialized, data-sensitive scenarios where big models are not present or applicable. This paper describes Beimingwu, the first open-source learnware dock system providing foundational support for future research of learnware paradigm.The system significantly streamlines the model development for new user tasks, thanks to its integrated architecture and engine design, extensive engineering implementations and optimizations, and the integration of various algorithms for learnware identification and reuse. Notably, this is possible even for users with limited data and minimal expertise in machine learning, without compromising the raw data's security. Beimingwu supports the entire process of learnware paradigm. The system lays the foundation for future research in learnware-related algorithms and systems, and prepares the ground for hosting a vast array of learnwares and establishing a learnware ecosystem

    (S)-3-Bromo-4-diallyl­amino-5-[(1R,2S,5R)-2-isopropyl-5-methyl­cyclo­hex­yloxy]furan-2(5H)-one

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    The title compound, C20H30BrNO3, was obtained via a tandem asymmetric Michael addition–elimination reaction of 3,4-dibromo-5-(S)-(l-menth­yloxy)-2(5H)-furan­one and diallyl­amine in the presence of potassium fluoride. In the mol­ecule, the five-membered furan­one ring is approximately planar [maximum atomic deviation = 0.030 (3) Å], and the six-membered cyclo­hexane ring adopts a chair conformation

    4-(2,4-Dichloro­phen­yl)-5,5-dimethyl-2-(3-silatranyl­propyl­mino)-1,3,2-dioxa­phospho­rinane 2-oxide

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    In the title compound, C20H31Cl2N2O6PSi, the dioxaphospho­rinane ring adopts a cis conformation. The silatrane fragment forms a cage-like structure in which there exists an intra­molecular Si—N donor–acceptor bond. In the crystal, centrosymmetrically related mol­ecules are linked by pairs of N—H⋯O hydrogen bonds into inversion dimers, generating rings with graph-set motif R 2 2(8). The dimers are further connected into ribbons parallel to the a axis by inter­molecular C—H⋯O hydrogen bonds

    1-(4-Methyl­benzo­yl)-3-[5-(4-pyrid­yl)-1,3,4-thia­diazol-2-yl]urea

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    In the title compound, C16H13N5O2S, the five non-H atoms of the urea linkage adopt a planar configuration owing to the presence of an intra­molecular N—H⋯O hydrogen bond. The maximum deviation from planarity is 0.022 (2) Å. The thia­diazole and pyridine heterocyclic rings are close to being coplanar, with a dihedral angle of 6.7 (2)° between their mean planes. Inter­molecular N—H⋯O hydrogen bonds link two neighbouring mol­ecules into centrosymmetric R 2 2(8) dimers. Four C atoms and the attached H atoms of the benzene ring are disordered over two positions of equal occupancy
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