3,016 research outputs found
Bioassay-guided identification of the antiproliferative compounds of cissus trifoliata and the transcriptomic effect of resveratrol in prostate cancer pc3 cells
The bioassay-guided fractionation of a CHCl3-MeOH extract from the stems of Cissus trifo-liata identified an active fraction against PC3 prostate cancer cells. The treatment for 24 h showed an 80% reduction in cell viability (p ≤ 0.05) by a WST-1 assay at a concentration of 100 µg/mL. The HPLC-QTOF-MS analysis of the fraction showed the presence of coumaric and isoferulic acids, apigenin, kaempferol, chrysoeriol, naringenin, ursolic and betulinic acids, hexadecadienoic and octadecadienoic fatty acids, and the stilbene resveratrol. The exposure of PC3 cells to resveratrol (IC25 = 23 µg/mL) for 24 h induced significant changes in 847 genes (Z-score ≥ ±2). The functional classification tool of the DAVID v6.8 platform indicates that the underlying molecular mechanisms against the proliferation of PC3 cells were associated (p ≤ 0.05) with the process of differentiation and metabolism. These findings provide experimental evidence suggesting the potential of C. trifoliata as a promising natural source of anticancer compounds
The physical parameters, excitation and chemistry of the rim, jets and knots of the planetary nebula NGC 7009
We present long-slit optical spectra along the major axis of the planetary
nebula NGC 7009. These data allow us to discuss the physical, excitation and
chemical properties of all the morphological components of the nebula,
including its remarkable systems of knots and jets. The main results of this
analysis are the following: i) the electron temperature throughout the nebula
is remarkably constant, T_e[OIII] = 10200K; ii) the bright inner rim and inner
pair of knots have similar densities of N_e = 6000cm^{-3}, whereas a much lower
density of N_e = 1500cm^{-3} is derived for the outer knots as well as for the
jets; iii) all the regions (rim, inner knots, jets and outer knots) are mainly
radiatively excited; and iv) there are no clear abundance changes across the
nebula for He, O, Ne, or S. There is a marginal evidence for an overabundance
of nitrogen in the outer knots (ansae), but the inner ones (caps) and the rim
have similar N/H values that are at variance with previous results. Our data
are compared to the predictions of theoretical models, from which we conclude
that the knots at the head of the jets are not matter accumulated during the
jet expansion through the circumstellar medium, neither can their origin be
explained by the proposed HD or MHD interacting-wind models for the formation
of jets/ansae, since the densities as well as the main excitation mechanisms of
the knots, disagree with model predictions.Comment: Figure 1 was changed because features were misidentified in the
previous version. 17 pages including 5 figures and 3 tables. ApJ in press.
Also available at http://www.iac.es/galeria/denise
Imprints of galaxy evolution on H ii regions Memory of the past uncovered by the CALIFA survey
H ii regions in galaxies are the sites of star formation and thus particular
places to understand the build-up of stellar mass in the universe. The line
ratios of this ionized gas are frequently used to characterize the ionization
conditions. We use the Hii regions catalogue from the CALIFA survey (~5000 H ii
regions), to explore their distribution across the classical [OIII]/Hbeta vs.
[NII]/Halpha diagnostic diagram, and how it depends on the oxygen abundance,
ionization parameter, electron density, and dust attenuation. We compared the
line ratios with predictions from photoionization models. Finally, we explore
the dependences on the properties of the host galaxies, the location within
those galaxies and the properties of the underlying stellar population. We
found that the location within the BPT diagrams is not totally predicted by
photoionization models. Indeed, it depends on the properties of the host
galaxies, their galactocentric distances and the properties of the underlying
stellar population. These results indicate that although H ii regions are short
lived events, they are affected by the total underlying stellar population. One
may say that H ii regions keep a memory of the stellar evolution and chemical
enrichment that have left an imprint on the both the ionizing stellar
population and the ionized gasComment: 18 pages, 8 figures, accepted for publishing in A&
The effects of spatial resolution on Integral Field Spectrograph surveys at different redshifts. The CALIFA perspective
Over the past decade, 3D optical spectroscopy has become the preferred tool
for understanding the properties of galaxies and is now increasingly used to
carry out galaxy surveys. Low redshift surveys include SAURON, DiskMass,
ATLAS3D, PINGS and VENGA. At redshifts above 0.7, surveys such as MASSIV, SINS,
GLACE, and IMAGES have targeted the most luminous galaxies to study mainly
their kinematic properties. The on-going CALIFA survey () is the
first of a series of upcoming Integral Field Spectroscopy (IFS) surveys with
large samples representative of the entire population of galaxies. Others
include SAMI and MaNGA at lower redshift and the upcoming KMOS surveys at
higher redshift. Given the importance of spatial scales in IFS surveys, the
study of the effects of spatial resolution on the recovered parameters becomes
important. We explore the capability of the CALIFA survey and a hypothetical
higher redshift survey to reproduce the properties of a sample of objects
observed with better spatial resolution at lower redshift. Using a sample of
PINGS galaxies, we simulate observations at different redshifts. We then study
the behaviour of different parameters as the spatial resolution degrades with
increasing redshift.Comment: 20 pages, 16 figures. Accepted for publication in A&
Extraction, characterization and incorporation of Hypericum scruglii extract in ad hoc formulated phospholipid vesicles designed for the treatment of skin diseases connected with oxidative stress
An extract of Hypericum scruglii, an endangered endemic plant of Sardinia (Italy), was prepared and characterized. It was loaded in special phospholipid vesicles, glycerosomes, which were modified by adding maltodextrin (glucidex) and a polymer (gelatin or hyaluronan). The corresponding liposomes were also prepared and used as reference. The vesicles disclosed suitable physicochemical features for skin delivery. Indeed, their mean diameter ranged from 120 to 160 nm, they were homogeneously dispersed (polydispersity index 0.30), and their zeta potential was highly negative (-45 mV). The vesicle dispersions maintained unchanged characteristics during 60 days of storage, were highly biocompatible, and were able to protect keratinocytes against damages due to oxidative stress induced by treating them with hydrogen peroxide. Vesicles were also capable of promoting cell proliferation and migration in vitro by means of a scratch wound assay. The results confirmed the fruitful delivery of the extract of H. scruglii in glycerosomes modified with glucidex and gelatin and their promising ability for skin protection and treatment
QED Logarithms in the Electroweak Corrections to the Muon Anomalous Magnetic Moment
We employ an effective Lagrangian approach to derive the leading-logarithm
two-loop electroweak contributions to the muon anomalous magnetic moment, a_mu.
We show that these corrections can be obtained using known results on the
anomalous dimensions of composite operators. We confirm the result of Czarnecki
et al. for the bosonic part and present the complete sin^2 \theta_W dependence
of the fermionic contribution. The approach is then used to compute the
leading-logarithm three-loop electroweak contribution to a_mu. Finally we
derive, in a fairly model-independent way, the QED improvement of new-physics
contributions to a_mu and to the electric dipole moment (EDM) of the electron.
We find that the QED corrections reduce the effect of new physics at the
electroweak scale by 6% (for a_mu) and by 11% (for the electron EDM).Comment: 13 page
Ionized gas kinematics of galaxies in the CALIFA survey I: Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems
This work provides an overall characterization of the kinematic behavior of
the ionized gas of the galaxies included in the Calar Alto Legacy Integral
field Area (CALIFA), offering kinematic clues to potential users of this survey
for including kinematical criteria for specific studies. From the first 200
galaxies observed by CALIFA, we present the 2D kinematic view of the 177
galaxies satisfying a gas detection threshold. After removing the stellar
contribution, we used the cross-correlation technique to obtain the radial
velocity of the dominant gaseous component. The main kinematic parameters were
directly derived from the radial velocities with no assumptions on the internal
motions. Evidence of the presence of several gaseous components with different
kinematics were detected by using [OIII] profiles. Most objects in the sample
show regular velocity fields, although the ionized-gas kinematics are rarely
consistent with simple coplanar circular motions. 35% of the objects present
evidence of a displacement between the photometric and kinematic centers larger
than the original spaxel radii. Only 17% of the objects in the sample exhibit
kinematic lopsidedness when comparing receding and approaching sides of the
velocity fields, but most of them are interacting galaxies exhibiting nuclear
activity. Early-type galaxies in the sample present clear photometric-kinematic
misaligments. There is evidence of asymmetries in the emission line profiles
suggesting the presence of kinematically distinct gaseous components at
different distances from the nucleus. This work constitutes the first
determination of the ionized gas kinematics of the galaxies observed in the
CALIFA survey. The derived velocity fields, the reported kinematic
peculiarities and the identification of the presence of several gaseous
components might be used as additional criteria for selecting galaxies for
specific studies.Comment: 38 pages, 16 figures, 4 tables. Paper accepted for publication in A&
Inter-species differences in polychlorinated biphenyls patterns from five sympatric species of odontocetes : Can PCBs be used as tracers of feeding ecology?
The authors gratefully acknowledge the assistance of volunteers from the Galician (CEMMA) and Portuguese (SPVS) stranding networks. The authors would like to thank R. Gallois and C. Trichet for their participation on total lipid content analysis. P. Méndez-Fernandez was supported during the research period through a PhD grant from the Fundação do Ministério de Ciência e Tecnologia de Portugal and ANIMATE project (SFRH/BD/36766/2007) and through a Science Without Borders (CSF) young talent postdoctoral grant of the Brazilian government. G. J. Pierce acknowledges support from the EU ANIMATE project (MEXC-CT-2006-042337), University of Aveiro and Caixa Geral de Depósitos (Portugal).Peer reviewedPostprin
Search for CP Violation in the decays D+ -> K_S pi+ and D+ -> K_S K+
A high statistics sample of photo-produced charm from the FOCUS(E831)
experiment at Fermilab has been used to search for direct CP violation in the
decays D+->K_S pi+ and D+ -> K_S K+. We have measured the following asymmetry
parameters relative to D+->K-pi+pi+: A_CP(K_S pi+) = (-1.6 +/- 1.5 +/- 0.9)%,
A_CP(K_S K+) = (+6.9 +/- 6.0 +/- 1.5)% and A_CP(K_S K+) = (+7.1 +/- 6.1 +/-
1.2)% relative to D+->K_S pi+. The first errors quoted are statistical and the
second are systematic. We also measure the relative branching ratios:
\Gamma(D+->\bar{K0}pi+)/\Gamma(D+->K-pi+pi+) = (30.60 +/- 0.46 +/- 0.32)%,
\Gamma(D+->\bar{K0}K+)/\Gamma(D+->K-pi+pi+) = (6.04 +/- 0.35 +/- 0.30)% and
\Gamma(D+->\bar{K0}K+)/\Gamma(D+->\bar{K0}pi+) = (19.96 +/- 1.19 +/- 0.96)%.Comment: 4 pages, 3 figure
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