326,595 research outputs found

    Using Different Approaches to Evaluate Individual Social Equity in Transport

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    Inequalities not only exist in the field of economics in relation to income and wealth, but also in other areas, such as the transport sector, where access to and use of different transport modes varies markedly across population groups, and which provides the means to access everyday living activities. A key concern within the transport sector is that inequality has extended beyond the traditional measures of travel, and now covers a wide range of effects relating to social exclusion, freedom, well-being and being able to access reasonable opportunities and resources. In order to address the aforementioned issues, an important question to resolve is what type of methods can be used to measure inequalities in transport most effectively. Therefore, this study aims to apply different approaches, including the Capabilities Approach (CA) and a further six inequality indices, namely the Gini coefficient, the Atkinson index, the Palma ratio, the Pietra ratio, the Schutz coefficient and the Theil index, to the case study using the relatively migrant-rich lower-income neighbourhood of Tuqiao, in Beijing, in order to assess individual transport-related social inequity issues. The findings suggest that the CA is useful in assessing transport-related inequalities where there are significant barriers to the take up of accessibility, for example where there are high levels of disadvantaged groups and disaggregated analysis can be undertaken. The Palma ratio appears to have a larger effect than the Gini coefficient and the other inequality indices when measuring transport-related social inequity. In addition, we also found that most income inequality methods adapted from econometrics may be better suited to measuring transport-related social inequity between different regions, cities or countries, or within the same area, but at different points in time, rather than to measuring a single neighbourhood as a whole. Finally, we argue that to what extent politicians or transport planners can use appropriate management tools to measure transport-related social inequalities may be significant in terms of the progress that can be made in the fight against social inequity in the transport field

    Flow Study in Relativistic Nuclear Collisions by Fourier Expansion of Azimuthal Particle Distributions

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    We propose a new method to study transverse flow effects in relativistic nuclear collisions by Fourier analysis of the azimuthal distribution on an event-by-event basis in relatively narrow rapidity windows. The distributions of Fourier coefficients provide direct information on the magnitude and type of flow. Directivity and two dimensional sphericity tensor, widely used to analyze flow, emerge naturally in our approach, since they correspond to the distributions of the first and second harmonic coefficients, respectively. The role of finite particle fluctuations and particle correlations is discussed.Comment: 14 pages, 3 figures included as figures.uu at the end, REVTE

    Incorporation of a selective sigma-2 receptor ligand enhances uptake of liposomes by multiple cancer cells

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    Background: The sigma-2 receptor is an attractive target for tumor imaging and targeted therapy because it is overexpressed in multiple types of solid tumors, including prostate cancer, breast cancer, and lung cancer. SV119 is a synthetic small molecule that binds to sigma-2 receptors with high affinity and specificity. This study investigates the utility of SV119 in mediating the selective targeting of liposomal vectors in various types of cancer cells. Methods: SV119 was covalently linked with polyethylene glycol-dioleyl amido aspartic acid conjugate (PEG-DOA) to generate a novel functional lipid, SV119-PEG-DOA. This lipid was utilized for the preparation of targeted liposomes to enhance their uptake by cancer cells. Liposomes with various SV119 densities (0, 1, 3, and 5 mole%) were prepared and their cellular uptake was investigated in several tumor cell lines. In addition, doxorubicin (DOX) was loaded into the targeted and unmodified liposomes, and the cytotoxic effect on the DU-145 cells was evaluated by MTT assay. Results: Liposomes with or without SV119-PEG-DOA both have a mean diameter of approximately 90 nm and a neutral charge. The incorporation of SV119-PEG-DOA significantly increased the cellular uptake of liposomes by the DU-145, PC-3, A549, 201T, and MCF-7 tumor cells, which was shown by fluorescence microscopy and the quantitative measurement of fluorescence intensity. In contrast, the incorporation of SV119 did not increase the uptake of liposomes by the normal BEAS-2B cells. In a time course study, the uptake of SV119 liposomes by DU-145 cells was also significantly higher at each time point compared to the unmodified liposomes. Furthermore, the DOX-loaded SV119 liposomes showed significantly higher cytotoxicity to DU-145 cells compared to the DOX-loaded unmodified liposomes. Conclusion: SV119 liposomes were developed for targeted drug delivery to cancer cells. The targeting efficiency and specificity of SV119 liposomes to cancer cells was demonstrated in vitro. The results of this study suggest that SV119-modified liposomes might be a promising drug carrier for tumor-targeted delivery. © 2012 Zhang et al, publisher and licensee Dove Medical Press Ltd
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