2,119 research outputs found
Anti-tumor and anti-angiogenic activity of novel hydantoin derivatives: Inhibition of VEGF secretion in liver metastatic osteosarcoma cells
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
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
We study properties of waves of frequencies above the photospheric acoustic
cut-off of 5.3 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
(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 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, defined as a time scale of evolution of
the planet's semi-major axis due to tides considered as a function of orbital
period 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 four days. It grows with the mass of the planet, being
of order five for a five Jupiter mass planet with the same . 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
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 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- forest, providing precise distance
measurements and with < 2% uncertainty in flat CDM. 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 , to
assess the current tension in 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
The third moment of the twist-3 part of the nucleon spin structure
function is generalized to arbitrary momentum transfer and is
evaluated in heavy baryon chiral perturbation theory (HBChPT) up to order
and in a unitary isobar model (MAID). We show how to link
as well as higher moments of the nucleon spin structure functions
and 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 which appears in the suppressed term in the twist
expansion of the spin structure function for proton and neutron.Comment: 30 pages, 7 figure
Study of parameters of CSR-2 cocoon reared with V1 mulberry leaves irrigated by spentwash
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
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
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
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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