2,119 research outputs found

    Anti-tumor and anti-angiogenic activity of novel hydantoin derivatives: Inhibition of VEGF secretion in liver metastatic osteosarcoma cells

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    A series of new azaspiro bicyclic hydantoin derivatives has been designed and synthesized. Initially, the anti-proliferative effect of the hydantoin derivatives was evaluated against human ovarian cancer cells (SKOV-3 and OVSAHO) and murine osteosarcoma cells (LM8 and LM8G7). Among the tested compounds, 8-(3-fluorobenzyl)-1′-(4-(methylsulfonyl)benzyl)-8-azaspiro[bicyclo[3.2.1]octane-3,4′-imidazolidine]-2′,5′-dione (7h) and 8-(3,4-difluorobenzyl)-1′-(4-(methylsulfonyl)benzyl)-8-azaspiro[bicyclo[3.2.1]octane-3,4′-imidazolidine]-2′,5′-dione (7i) showed a significant anti-proliferative activity against the OVSAHO and LM8G7 cells. The real-time monitoring of the effect of the compounds 7h and 7i against the proliferation of LM8G7 was revealed that resulting IC50 values were 102 μM and 13 μM, respectively. We reasoned that the presence of fluorine atom at the 3rd position of the phenyl ring of the hydantoin side chain may determine the potency of the molecule. Furthermore, the compound 7i inhibited the tube formation of the mouse endothelial cells. Finally, the treatment of the compound 7i against the proliferation of LM8G7 cells demonstrated the down regulation of the secretion of VEGF, indicate the potential angioinhibitory effects. In conclusion, our findings demonstrate the suppression of the secretion of VEGF by LM8G7 cells by the compound 7i might contribute at least in part to the antitumor action

    B_s --> mu+ mu- decay in the R-parity violating minimal supergravity

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    We study B_s --> mu+ mu- in the context of the R-parity violating minimal supergravity in the high tan beta regime. We find that the lowest value of the branching ratio can go well below the present LHCb sensitivity and hence B_s --> mu+ mu- can even be invisible to the LHC. We also find that the present upper bound on Br(B_s --> mu+ mu-) puts strong constraint on the minimal supergravity parameter space. The constraints become more severe if the upper bound is close to its standard model prediction.Comment: 18 pages, 10 figures; version to be published in European Physical Journal

    Properties of high-frequency wave power halos around active regions: an analysis of multi-height data from HMI and AIA onboard SDO

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    We study properties of waves of frequencies above the photospheric acoustic cut-off of \approx5.3 mHz, around four active regions, through spatial maps of their power estimated using data from Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). The wavelength channels 1600 {\AA} and 1700 {\AA} from AIA are now known to capture clear oscillation signals due to helioseismic p modes as well as waves propagating up through to the chromosphere. Here we study in detail, in comparison with HMI Doppler data, properties of the power maps, especially the so called 'acoustic halos' seen around active regions, as a function of wave frequencies, inclination and strength of magnetic field (derived from the vector field observations by HMI) and observation height. We infer possible signatures of (magneto-)acoustic wave refraction from the observation height dependent changes, and hence due to changing magnetic strength and geometry, in the dependences of power maps on the photospheric magnetic quantities. We discuss the implications for theories of p mode absorption and mode conversions by the magnetic field.Comment: 22 pages, 12 figures, Accepted by journal Solar Physic

    Close encounters of a rotating star with planets in parabolic orbits of varying inclination and the formation of Hot Jupiters

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    (abbreviated) We extend the theory of close encounters of a planet on a parabolic orbit with a star to include the effects of tides induced on the central rotating star. Orbits with arbitrary inclination to the stellar rotation axis are considered. We obtain results both from an analytic treatment and numerical one that are in satisfactory agreement. These results are applied to the initial phase of the tidal circularisation problem. We find that both tides induced in the star and planet can lead to a significant decrease of the orbital semi-major axis for orbits having periastron distances smaller than 5-6 stellar radii (corresponding to periods 45\sim 4-5 days after the circularisation has been completed) with tides in the star being much stronger for retrograde orbits compared to prograde orbits. We use the simple Skumanich law for the stellar rotation with its rotational period equal to one month at the age of 5Gyr. The strength of tidal interactions is characterised by circularisation time scale, tevt_{ev} defined as a time scale of evolution of the planet's semi-major axis due to tides considered as a function of orbital period PobsP_{obs} after the process of tidal circularisation has been completed. We find that the ratio of the initial circularisation time scales corresponding to prograde and retrograde orbits is of order 1.5-2 for a planet of one Jupiter mass and PobsP_{obs}\sim four days. It grows with the mass of the planet, being of order five for a five Jupiter mass planet with the same PorbP_{orb}. Thus, the effect of stellar rotation may provide a bias in the formation of planetary systems having planets on close orbits around their host stars, as a consequence of planet-planet scattering, favouring systems with retrograde orbits. The results may also be applied to the problem of tidal capture of stars in young stellar clusters.Comment: to be published in Celestial Mechanics and Dynamical Astronom

    Cosmological distance indicators

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    We review three distance measurement techniques beyond the local universe: (1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and (3) HI intensity mapping. We describe the principles and theory behind each method, the ingredients needed for measuring such distances, the current observational results, and future prospects. Time delays from strongly lensed quasars currently provide constraints on H0H_0 with < 4% uncertainty, and with 1% within reach from ongoing surveys and efforts. Recent exciting discoveries of strongly lensed supernovae hold great promise for time-delay cosmography. BAO features have been detected in redshift surveys up to z <~ 0.8 with galaxies and z ~ 2 with Ly-α\alpha forest, providing precise distance measurements and H0H_0 with < 2% uncertainty in flat Λ\LambdaCDM. Future BAO surveys will probe the distance scale with percent-level precision. HI intensity mapping has great potential to map BAO distances at z ~ 0.8 and beyond with precisions of a few percent. The next years ahead will be exciting as various cosmological probes reach 1% uncertainty in determining H0H_0, to assess the current tension in H0H_0 measurements that could indicate new physics.Comment: Review article accepted for publication in Space Science Reviews (Springer), 45 pages, 10 figures. Chapter of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Ag

    Higher moments of nucleon spin structure functions in heavy baryon chiral perturbation theory and in a resonance model

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    The third moment d2d_2 of the twist-3 part of the nucleon spin structure function g2g_2 is generalized to arbitrary momentum transfer Q2Q^2 and is evaluated in heavy baryon chiral perturbation theory (HBChPT) up to order O(p4){\mathcal{O}}(p^4) and in a unitary isobar model (MAID). We show how to link d2d_2 as well as higher moments of the nucleon spin structure functions g1g_1 and g2g_2 to nucleon spin polarizabilities. We compare our results with the most recent experimental data, and find a good description of these available data within the unitary isobar model. We proceed to extract the twist-4 matrix element f2f_2 which appears in the 1/Q21/Q^2 suppressed term in the twist expansion of the spin structure function g1g_1 for proton and neutron.Comment: 30 pages, 7 figure

    Study of parameters of CSR-2 cocoon reared with V1 mulberry leaves irrigated by spentwash

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    CSR-2 silkworm reared with V1 variety of mulberry plants irrigated by raw water,50% PTSW and 33% PTSW. The different parameters such as raw silk (%), filamentlength (m), reelability (%), denier and shell ratio were determined at the maturity ofcocoons. It was found that the parameters werebetter in cocoon irrigated with 33%PTSWcompared to 50%PTSW and raw water irrigations. This concludes that the mulberryplants irrigated with 33%PTSW is enriched with more nutrients for the potential growthof mulberry plants which results in the potential cocoons

    Sprouting and Growth studies of Rose (Rosa) and Hibiscus (Hibiscus rosasinenis) flowering plants irrigated by distillery spentwash

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    Sprouting and growth of Rose (Rosa) and Hibiscus (Hibiscus rosasinenis) flowering plants was made by irrigated with distillery spentwash of different concentrations. Thespentwash i.e., primary treated spentwash (PTSW), 1:1, 1:2, and 1:3 spent wash were analyzedfor their plant nutrients such as nitrogen, phosphorous, potassium and other physical andchemical characteristics. Experimental soil was tested for its chemical and physical parameters.Rose and Hibiscus sets were planted in different pots and irrigated with raw water (RW), 1:1,1:2 and 1:3 spentwash. The nature of sprouting and growth was studied. It was found that thesprouting and growth of both plants was very good (100%) in 1:3 SW irrigation, while very poor(25%) in 1:1 SW, moderate (80%) in 1:2 SW and 95% in RW irrigation growth

    Stabilization of a Highly Concentrated Colloidal Suspension of Pristine Metallic Nanoparticles

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    A colloidal suspension containing a high concentration of metallic nanoparticles (NPs) finds potential applications in flexible electronic printing, nanofluids, healthcare, antifouling coating, and so on. Here, we demonstrate a generic, easily scalable, simple, and contamination-free cryogenic temperature grinding method, which can effectively be used to prepare pristine NPs that can be stabilized in polar liquids in high concentrations. These surfactant-free pristine NPs have been found to remain dispersed in different polar liquids (CH3OH, C2H5OH, glycol, etc.) for weeks. The long-term stability of the NPs in these liquids has been investigated using zeta potential, in situ Fourier transform infrared spectroscopy, indicating electrostatic stabilization for ultrapure, surfactant-free NPs. Furthermore, stabilization of the NPs has been probed with detailed calculations using the Derjaguin Landau Verwey Overbeek theory as well as atomistic molecular dynamics simulation (MD). Experimental measurements along with theoretical calculations categorically indicate that the electrostatic energy is helping these NPs to be stabilized in a polar liquid

    A Measurement of the Branching Fraction for the Inclusive B --> X(s) gamma Decays with the Belle Detector

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    We have measured the branching fraction of the inclusive radiative B meson decay B --> X(s) gamma to be Br(B->X(s)gamma)=(3.36 +/- 0.53(stat) +/- 0.42(sys) +0.50-0.54(th)) x 10^{-4}. The result is based on a sample of 6.07 x 10^6 BBbar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.Comment: 14 pages, 6 Postsript figures, uses elsart.cl
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