27,835 research outputs found

    Effects of Recombinant Human Endostatin and Docetaxel on MMP and its Following Anti-neoplastic Effect under Different Administration Sequences

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    Background and objective The aim of this study is to observe the changes of MMP-2 and its regulators, and to investigate the mechanism of the two administration sequences of recombinant human endostatin (rh-endostatin) and docetaxel. Methods The experiment was performed as 2 stages. Firstly, nude mice with xenograft tumor were randomized into 2 groups as rh-endostatin-treated group with rh-endostatin 400 μg•d-1, d1-d14 and docetaxel-traeted group with docetaxel 10 mg•kg-1•3d-1, d1-d14. Secondly, nude mice with xenograft tumor were randomized into 3 groups as concurrent administration group (rh-endostatin 400 μg•d-1, d1-d35, docetaxel 10 mg•kg-1•3d-1, d1-d19), endo-first group (rh-endostatin 400 μg•d-1, d1-d35, docetaxel 10 mg•kg-1•3d-1, d16-d34) and model group (positive control, mice burdened tumor without treatment). The volume of tumor was measured during treatment. Detection of the expressions of MMP-2, TIMP-2, EMMPRIN and the count of microvessel density (MVD) by immunohistochemistry stain examination were carried out at the end of experiment. Results Compared with the docetaxel-treated group, more obvious down-regulation of expression of MMP-2, EMMPRIN (P=0.024, P=0.081) were observed in rh-endostatin-treated group. No significant difference was found in TIMP-2 expression between the 2 groups. In combined treatment groups, at the endpoint tumor volumes of concurrent administration group and the endo-first group were remarkably smaller than that in model group (P<0.001, P=0.003). According to the administration procedure, concurrent administration inhibited tumor growth stronger than endo-first treatment did. Both of the combined groups down-regulated the expression of MMP-2 and decreased microvessel density (P<0.05). Compared with model group, the expression of TIMP-2 was upregulated (P=0.001) as well as EMMPRIN down-regulated (P=0.018) in concurrent adminis-tration group. Oppositely, the same results were not observed in the endo-first group. Conclusion The schedule of the concurrent administration group could inhibit the tumor growth better, and it down-regulated MMP-2 expression through TIMP-2 and EMMPRIN, and thus slow down the tumor growth superiorly to another schedule of treatment

    Polarization Decomposition Algorithm for Detection Efficiency Enhancement

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    In the paper, a new polarization decomposition of the optimal detection algorithm in the partially homogeneous environment is presented. Firstly, the detectors Matched Subspace Detector (MSD) and Adaptive Subspace Detector (ASD) are adopted to deal with detection problems in the partially homogeneous environment. Secondly, the fitness function with polarization parameters is equivalently decomposed to enhance time detection efficiency in the algorithm. It makes the multiplication number of the fitness function from square to a linear increase along with the increase in parameters. Simulation results indicate that the proposed decomposition is much more efficient than direct use of the fitness function

    Determination of Dark Matter Halo Mass from Dynamics of Satellite Galaxies

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    We show that the mass of a dark matter halo can be inferred from the dynamical status of its satellite galaxies. Using 9 dark-matter simulations of halos like the Milky Way (MW), we find that the present-day substructures in each halo follow a characteristic distribution in the phase space of orbital binding energy and angular momentum, and that this distribution is similar from halo to halo but has an intrinsic dependence on the halo formation history. We construct this distribution directly from the simulations for a specific halo and extend the result to halos of similar formation history but different masses by scaling. The mass of an observed halo can then be estimated by maximizing the likelihood in comparing the measured kinematic parameters of its satellite galaxies with these distributions. We test the validity and accuracy of this method with mock samples taken from the simulations. Using the positions, radial velocities, and proper motions of 9 tracers and assuming observational uncertainties comparable to those of MW satellite galaxies, we find that the halo mass can be recovered to within \sim40%. The accuracy can be improved to within \sim25% if 30 tracers are used. However, the dependence of the phase-space distribution on the halo formation history sets a minimum uncertainty of \sim20% that cannot be reduced by using more tracers. We believe that this minimum uncertainty also applies to any mass determination for a halo when the phase space information of other kinematic tracers is used.Comment: Accepted for publication in ApJ, 18 pages, 13 figure

    A feedback-driven bubble G24.136+00.436: a possible site of triggered star formation

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    We present a multi-wavelength study of the IR bubble G24.136+00.436. The J=1-0 observations of 12^{12}CO, 13^{13}CO and C18^{18}O were carried out with the Purple Mountain Observatory 13.7 m telescope. Molecular gas with a velocity of 94.8 km s1^{-1} is found prominently in the southeast of the bubble, shaping as a shell with a total mass of 2×104\sim2\times10^{4} MM_{\odot}. It is likely assembled during the expansion of the bubble. The expanding shell consists of six dense cores. Their dense (a few of 10310^{3} cm3^{-3}) and massive (a few of 10310^{3} MM_{\odot}) characteristics coupled with the broad linewidths (>> 2.5 km s1^{-1}) suggest they are promising sites of forming high-mass stars or clusters. This could be further consolidated by the detection of compact HII regions in Cores A and E. We tentatively identified and classified 63 candidate YSOs based on the \emph{Spitzer} and UKIDSS data. They are found to be dominantly distributed in regions with strong emission of molecular gas, indicative of active star formation especially in the shell. The HII region inside the bubble is mainly ionized by a \simO8V star(s), of the dynamical age \sim1.6 Myr. The enhanced number of candidate YSOs and secondary star formation in the shell as well as time scales involved, indicate a possible scenario of triggering star formation, signified by the "collect and collapse" process.Comment: 13 pages, 10 figures, 4 tables, accepted by Ap
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