7,445 research outputs found

    Curcumin inhibits cell proliferation of MDA-MB-231 and BT-483 breast cancer cells mediated by down-regulation of NFκB, cyclinD and MMP-1 transcription

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    Curcumin, an active constituent of turmeric, has been shown to possess inhibitory effect of cell proliferation and induction of apoptosis towards a board range of tumors. Cell inhibition activities of curcumin are behaved differently in various cell types. To investigate the mechanism basis for the cell inhibition of curcumin on breast cancer cell lines, we examine curcumin effect on NFκB, cell cycle regulatory proteins and matrix metalloproteinases (MMPs) in two breast cancer cell lines (MDA-MB-231 and BT-483). Cell proliferation was performed by water soluble tetrazolium WST-1 assay. The effect of curcumin's on the activity of matrix metalloproteinase-1, 3, 9 were analyzed by RT-PCR. Cell cycle regulatory protein including cyclin D1, CDK4 and p21 were examined by immunochemistry. The expressions of NFκB in breast cancer cells treated with curcumin were studied by immunochemistry and western blot. The results from WST-1 cell proliferation assay showed that curcumin exhibited the anti-proliferation effect on MDA-MB-231 and BT-483 cells in a time- and dose-dependent manner. In response to the treatment, while, the expression of cyclin D1 had declined in MDA-MB-231 and the expression of CDK4 in BT-483 had declined. MMP1 mRNA expression in BT-483 and MDA-MB-231 had significantly decreased in curcumin treatment group compared with control group. Our finding extrapolates the antitumor activity of curcumin in mediating the breast cancer cell proliferative rate and invasion by down-regulating the NFκB inducing genes. © 2009 Elsevier GmbH. All rights reserved.postprin

    Conductance plateau in quantum spin transport through an interacting quantum dot

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    Quantum spin transport is studied in an interacting quantum dot. It is found that a conductance "plateau" emerges in the non-linear charge conductance by a spin bias in the Kondo regime. The conductance plateau, as a complementary to the Kondo peak, originates from the strong electron correlation and exchange processes in the quantum dot, and can be regarded as one of the characteristics in quantum spin transport.Comment: 5 pages, 5 figure

    Development of a Classical Force Field for the Oxidised Si Surface: Application to Hydrophilic Wafer Bonding

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    We have developed a classical two- and three-body interaction potential to simulate the hydroxylated, natively oxidised Si surface in contact with water solutions, based on the combination and extension of the Stillinger-Weber potential and of a potential originally developed to simulate SiO2 polymorphs. The potential parameters are chosen to reproduce the structure, charge distribution, tensile surface stress and interactions with single water molecules of a natively oxidised Si surface model previously obtained by means of accurate density functional theory simulations. We have applied the potential to the case of hydrophilic silicon wafer bonding at room temperature, revealing maximum room temperature work of adhesion values for natively oxidised and amorphous silica surfaces of 97 mJ/m2 and 90mJ/m2, respectively, at a water adsorption coverage of approximately 1 monolayer. The difference arises from the stronger interaction of the natively oxidised surface with liquid water, resulting in a higher heat of immersion (203 mJ/m2 vs. 166 mJ/m2), and may be explained in terms of the more pronounced water structuring close to the surface in alternating layers of larger and smaller density with respect to the liquid bulk. The computed force-displacement bonding curves may be a useful input for cohesive zone models where both the topographic details of the surfaces and the dependence of the attractive force on the initial surface separation and wetting can be taken into account

    A model for luminescence of localized state ensemble

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    A distribution function for localized carriers, f(E,T)=1e(E−Ea)/kBT+τtr/τrf(E,T)=\frac{1}{e^{(E-E_a)/k_BT}+\tau_{tr}/\tau_r}, is proposed by solving a rate equation, in which, electrical carriers' generation, thermal escape, recapture and radiative recombination are taken into account. Based on this distribution function, a model is developed for luminescence from localized state ensemble with a Gaussian-type density of states. The model reproduces quantitatively all the anomalous temperature behaviors of localized state luminescence. It reduces to the well-known band-tail and luminescence quenching models under certain approximations.Comment: 14 pages, 4 figure

    Towards sustainability: An assessment of an urbanisation bubble in China using a hierarchical - Stochastic multicriteria acceptability analysis - Choquet integral method

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    Urbanisation bubbles have become an increasingly serious problem. Attention has been paid to the speed of urbanisation; however, the issue of quality has been neglected, particularly in the case of China. Therefore, the aim of this research is to evaluate China's urbanisation bubbles by employing a hierarchical - stochastic multicriteria acceptability analysis (SMAA) - Choquet integral method. In order to highlight regional disparities, we measure the urbanisation bubbles at a provincial level. Our study aggregates the urbanisation bubble indices using the Choquet integral preference model, and considers the interactions between various indicators. Furthermore, robust ordinal regression and SMAA are applied to resolve the robustness issues associated with the entire set of weights assigned to the urbanisation bubble composite indicator. In addition, by employing a multiple criteria hierarchy process, the study aggregates urbanisation bubble indices not only at the comprehensive level, but also at the intermediate levels of the hierarchy. Our findings suggest that the ranking of urbanisation bubbles is positively related to the level of regional development. This study contributes to the evaluation of regional urbanisation and sustainable development

    Angle-Resolved X-Ray Circular and Magnetic Circular Dichroisms: Definitions and Applications

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    We introduce definitions of angle-resolved x-ray circular dichroism (ARXCD) and magnetic x-ray circular dichroism (ARMXCD). As defined, the much larger effect of circular dichroism (ARXCD) is separated from the smaller magnetic (ARMXCD) effect. In all materials, ARXCD is zero along mirror planes while nonzero elsewhere. ARMXCD is nonzero only in magnetic materials. The measurement and analysis of ARMXCD allow element specific surface magnetism and surface structure as well as their inter-relationship to be studied as functions of the outgoing electron\u27s direction

    Opportunities for improving waterlogging tolerance in cereal crops—Physiological traits and genetic mechanisms

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    Waterlogging occurs when soil is saturated with water, leading to anaerobic conditions in the root zone of plants. Climate change is increasing the frequency of waterlogging events, resulting in considerable crop losses. Plants respond to waterlogging stress by adventitious root growth, aerenchyma formation, energy metabolism, and phytohormone signalling. Genotypes differ in biomass reduction, photosynthesis rate, adventitious roots development, and aerenchyma formation in response to waterlogging. We reviewed the detrimental effects of waterlogging on physiological and genetic mechanisms in four major cereal crops (rice, maize, wheat, and barley). The review covers current knowledge on waterlogging tolerance mechanism, genes, and quantitative trait loci (QTL) associated with waterlogging tolerance-related traits, the conventional and modern breeding methods used in developing waterlogging tolerant germplasm. Lastly, we describe candidate genes controlling waterlogging tolerance identified in model plants Arabidopsis and rice to identify homologous genes in the less waterlogging-tolerant maize, wheat, and barley
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