1,348 research outputs found

    Prediction of Vortex-Induced Vibration of Long Flexible Cylinders Modeled by a Coupled Nonlinear Oscillator: Integral Transform Solution

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    The Generalized Integral Transform Technique (GITT) was applied to predict dynamic response of Vortex-Induced Vibration (VIV) of a long flexible cylinder. A nonlinear wake oscillator model was used to represent the cross-flow force acting on the cylinder, leading to a coupled system of second-order Partial Differential Equations (PDEs) in temporal variable. The GITT approach was used to transform the system of PDEs to a system of Ordinary Differential Equations (ODEs), which was numerically solved by using the Adams-Moulton and Gear method (DIVPAG) developed by the International Mathematics and Statistics Library (IMSL). Numerical results were presented for comparison to those given by the finite difference method and experimental results, allowing a critical evaluation of the technique performance. The influence of variation of mean axial tension induced by elongation of flexible cylinder was evaluated, which was shown to be not negligible in numerical simulation of VIV of a long flexible cylinder.Indisponível

    In vitro antioxidant activity and inhibitory hepatic steatosis effect on oleic acid-induced fatty liver model of consecutive extracts from Rosa davurica Pall

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    The nutrient and phytochemical composition of Rosa davurica Pall. fruit (RDF) from China were determined, including sugar, reducing sugar, ascorbic acid, caroteniods and phenolics. RDF was successively extracted with chloroform, ethyl acetate (EA), water-saturated n-butanol, ethanol and distilled water, respectively. Among the five fractions, EA fraction revealed the highest total phenolic content and the strongest antioxidant ability in cyclic voltammograms (CV) and oxygen radical absorbance capacity (ORAC) assays. Moreover, the strongest inhibitory activity against oleic acidinduced (OA-induced) fatty liver in vitro was also the EA fraction. Further, it was separated by a semipreparative high performance liquid chromatography (HPLC) on C18 column. The most active fraction (EA-FII) of EA in all assays above, which mainly included catechin, quercetin-sedoheptulose and quercetin-94, was identified by LC/MS, HPLC and ultraviolet (UV)/V spectrum analysis.Keywords: RDF extracts, composition properties, antioxidant ability, inhibitory activity, oleic acid-induced, HPLC, LC/MS.African Journal of Biotechnology Vol. 12(31), pp. 4944-495

    Numerical Analysis of Stress Intensity Factors of a Crack in the Composite Patch Repair

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    The composite patch repair technology can be utilized to provide upgrades, such as higher design requirements and life extensions. However, in this case, failures easily happen on the edge interface between the substrate material and the restorative material, because of the incompatible of different properties. Failures such as flaws or cracks lying along the interface reduce the strength of the structure significantly. In this paper, the numerical solutions of hypersingular integro-differential equations are discussed in the analysis of three dimensional interfacial cracks subjected to general internal pressure,and the problem is formulated on the basis of the body force method.The stress intensity factors are given with varying material combinations. It is found that the stress intensity factors and are determined by the bi-materials constant alone, independent of elastic modulus ratio and Poisson\u27s ratio.25th International Ocean and Polar Engineering Conference (ISOPE-2015), Kona, Big Island, Hawaii, USA, June 21-26, 201

    Bis(1-methyl-1H-imidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κO]copper(II) monohydrate

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    In the crystal structure of the title compound, [Cu(C12H9O2)2(C4H6N2)2]·H2O, the CuII atom is coordinated by two 2-(naphthalen-1-yl)acetate anions and two 1-methyl­imidazole ligands, giving monomeric complexes with a square-planar coordination environment. Two complex mol­ecules and two water mol­ecules form a centrosymmetric ring system via O—H⋯O hydrogen bonds

    Unleashing the full potential of Hsp90 inhibitors as cancer therapeutics through simultaneous inactivation of Hsp90, Grp94, and TRAP1

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    Cancer therapeutics: Extending a drug's reach A new drug that blocks heat shock proteins (HSPs), helper proteins that are co-opted by cancer cells to promote tumor growth, shows promise for cancer treatment. Several drugs have targeted HSPs, since cancer cells are known to hijack these helper proteins to shield themselves from destruction by the body. However, the drugs have had limited success. Hye-Kyung Park and Byoung Heon Kang at Ulsan National Institutes of Science and Technology in South Korea and coworkers noticed that the drugs were not absorbed into mitochondria, a key cellular compartment, and HSPs in this compartment were therefore not being blocked. They identified a new HSP inhibitor that can reach every cellular compartment and inhibit all HSPs. Testing in mice showed that this inhibitor effectively triggered death of tumor cells, and therefore shows promise for anti-cancer therapy. The Hsp90 family proteins Hsp90, Grp94, and TRAP1 are present in the cell cytoplasm, endoplasmic reticulum, and mitochondria, respectively; all play important roles in tumorigenesis by regulating protein homeostasis in response to stress. Thus, simultaneous inhibition of all Hsp90 paralogs is a reasonable strategy for cancer therapy. However, since the existing pan-Hsp90 inhibitor does not accumulate in mitochondria, the potential anticancer activity of pan-Hsp90 inhibition has not yet been fully examined in vivo. Analysis of The Cancer Genome Atlas database revealed that all Hsp90 paralogs were upregulated in prostate cancer. Inactivation of all Hsp90 paralogs induced mitochondrial dysfunction, increased cytosolic calcium, and activated calcineurin. Active calcineurin blocked prosurvival heat shock responses upon Hsp90 inhibition by preventing nuclear translocation of HSF1. The purine scaffold derivative DN401 inhibited all Hsp90 paralogs simultaneously and showed stronger anticancer activity than other Hsp90 inhibitors. Pan-Hsp90 inhibition increased cytotoxicity and suppressed mechanisms that protect cancer cells, suggesting that it is a feasible strategy for the development of potent anticancer drugs. The mitochondria-permeable drug DN401 is a newly identified in vivo pan-Hsp90 inhibitor with potent anticancer activity

    Wireless thin film transistor based on micro magnetic induction coupling antenna

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    A wireless thin film transistor (TFT) structure in which a source/drain or a gate is connected directly to a micro antenna to receive or transmit signals or power can be an important building block, acting as an electrical switch, a rectifier or an amplifier, for various electronics as well as microelectronics, since it allows simple connection with other devices, unlike conventional wire connections. An amorphous indium gallium zinc oxide (α-IGZO) TFT with magnetic antenna structure was fabricated and studied for this purpose. To enhance the induction coupling efficiency while maintaining the same small antenna size, a magnetic core structure consisting of Ni and nanowires was formed under the antenna. With the micro-antenna connected to a source/drain or a gate of the TFT, working electrical signals were well controlled. The results demonstrated the device as an alternative solution to existing wire connections which cause a number of problems in various fields such as flexible/wearable devices, body implanted devices, micro/nano robots, and sensors for the 'internet of things' (IoT).1

    N′-(4-Diethyl­amino-2-hy­droxy­benzyl­idene)-4-(dimethyl­amino)­benzo­hydrazide methanol monosolvate

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    The title compound, C20H26N4O2·CH3OH, was prepared by the reaction of 4-diethyl­amino-2-hy­droxy­benzaldehyde with 4-(dimethyl­amino)­benzohydrazide. The dihedral angle between the two benzene rings is 13.6 (3)° and an intra­molecular O—H⋯N hydrogen bond generates an S(6) ring. In the crystal, the hydrazone and methanol mol­ecules are linked through inter­molecular O—H⋯O and N—H⋯O hydrogen bonds, forming chains along a
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