317 research outputs found
Phospho-kinase profile of triple negative breast cancer and androgen receptor signaling
BACKGROUND: The androgen receptor (AR) plays a central role in the oncogenesis of different tumors, as is the case in prostate cancer. In triple negative breast cancer (TNBC) a gene expression classification has described different subgroups including a luminal androgen subtype. The AR can be controlled by several mechanisms like the activation of membrane tyrosine kinases and downstream signaling pathways. However little is known in TNBC about how the AR is modulated by these mechanisms and the potential therapeutic strategists to inhibit its expression. METHODS: We used human samples to evaluate the expression of AR by western-blot and phospho-proteomic kinase arrays that recognize membrane tyrosine kinase receptors and downstream mediators. Western-blots in human cell lines were carried out to analyze the expression and activation of individual proteins. Drugs against these kinases in different conditions were used to measure the expression of the androgen receptor. PCR experiments were performed to assess changes in the AR gene after therapeutic modulation of these pathways. RESULTS: AR is present in a subset of TNBC and its expression correlates with activated membrane receptor kinases-EGFR and PDGFRβ in human samples and cell lines. Inhibition of the PI3K/mTOR pathway in TNBC cell lines decreased notably the expression of the AR. Concomitant administration of the anti-androgen bicalutamide with the EGFR, PDGFRβ and Erk1/2 inhibitors, decreased the amount of AR compared to each agent given alone, and had an additive anti-proliferative effect. Administration of dihydrotestosterone augmented the expression of AR that was not modified by the inhibition of the PI3K/mTOR or Erk1/2 pathways. AR expression was posttranscriptionally regulated by PI3K or Erk1/2 inhibition. CONCLUSION: Our results describe the expression of the AR in TNBC as a druggable target and further suggest the combination of bicalutamide with inhibitors of EGFR, PDGFRβ or Erk1/2 for future development
Validity and reliability of the new Basic Functional Assessment protocol (BFA)
The global evaluation of motion patterns can examine the synchrony of neuromuscular control, range of motion, strength, resistance, balance and coordination needed to complete the movement. Visual assessments are commonly used to detect risk factors. However, it is essential to define standardized field-based tests that can evaluate with accuracy. The aims of the study were to design a protocol to evaluate fundamental motor patterns (FMP), and to analyze the validity and reliability of an instrument created to provide information about the quality of movement in FMP. Five tasks were selected: Overhead Squat (OHS); Hurdle Step (HS); Forward Step Down (FSD); Shoulder Mobility (SM); Active Stretching Leg Raise (ASLR). A list of variables was created for the evaluation of each task. Ten qualified judges assessed the validity of the instrument, while six external observers performed inter-intra reliability. The results show that the instrument is valid according to the experts’ opinion; however, the reliability shows values below those established. Thus, the instrument was considered unreliable, so it is recommended to repeat the reliability process by performing more training sessions for the external observers. The present study creates the basic functional assessment (BFA), a new protocol which comprises five tasks and an instrument to evaluate FMP
Stellar populations of galaxies in the ALHAMBRA survey up to . II. Stellar content of quiescent galaxies within the dust-corrected stellar masscolour and the colourcolour diagrams
Our aim is to determine the distribution of stellar population parameters
(extinction, age, metallicity, and star formation rate) of quiescent galaxies
within the rest-frame stellar masscolour and colourcolour diagrams
corrected for extinction up to . These novel diagrams reduce the
contamination in samples of quiescent galaxies owing to dust-reddened galaxies,
and they provide useful constraints on stellar population parameters. We set
constraints on the stellar population parameters of quiescent galaxies
combining the ALHAMBRA multi-filter photo-spectra with our SED-fitting code
MUFFIT, making use of composite stellar population models. The extinction
obtained by MUFFIT allowed us to remove dusty star-forming (DSF) galaxies from
the sample of red galaxies. The distributions of stellar population
parameters across these rest-frame diagrams are revealed after the dust
correction and are fitted by the LOESS method to reduce uncertainty effects.
Quiescent galaxy samples defined via classical diagrams are typically
contaminated by a % fraction of DSF galaxies. A significant part of the
galaxies in the green valley are actually obscured star-forming galaxies
(%). Consequently, the transition of galaxies from the blue cloud to
the red sequence, and hence the related mechanisms for quenching, seems to be
much more efficient and faster than previously reported. The rest-frame stellar
masscolour and colourcolour diagrams are useful for constraining
the age, metallicity, extinction, and star formation rate of quiescent galaxies
by only their redshift, rest-frame colours, and/or stellar mass. Dust
correction plays an important role in understanding how quiescent galaxies are
distributed in these diagrams and is key to performing a pure selection of
quiescent galaxies via intrinsic colours.Comment: (37 pages, 29 figures, accepted for publication in A&A
The ALHAMBRA survey: evolution of galaxy spectral segregation
We study the clustering of galaxies as a function of spectral type and
redshift in the range using data from the Advanced Large
Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The data
cover 2.381 deg in 7 fields, after applying a detailed angular selection
mask, with accurate photometric redshifts [] down to
. From this catalog we draw five fixed number density,
redshift-limited bins. We estimate the clustering evolution for two different
spectral populations selected using the ALHAMBRA-based photometric templates:
quiescent and star-forming galaxies. For each sample, we measure the real-space
clustering using the projected correlation function. Our calculations are
performed over the range Mpc, allowing us to find a
steeper trend for Mpc, which is especially clear for
star-forming galaxies. Our analysis also shows a clear early differentiation in
the clustering properties of both populations: star-forming galaxies show
weaker clustering with evolution in the correlation length over the analysed
redshift range, while quiescent galaxies show stronger clustering already at
high redshifts, and no appreciable evolution. We also perform the bias
calculation where similar segregation is found, but now it is among the
quiescent galaxies where a growing evolution with redshift is clearer. These
findings clearly corroborate the well known colour-density relation, confirming
that quiescent galaxies are mainly located in dark matter halos that are more
massive than those typically populated by star-forming galaxies.Comment: 14 pages, 9 figures, accepted by Ap
Comparison of fiber effect on glycemic index and glycemic load in differents types of bread
Indexación: Scopus; Redalyc.Existen diversos alimentos que contienen como nutriente
principal hidratos de carbono, destacando entre ellos el pan
por su masivo consumo a nivel mundial. Numerosos estudios
se han llevado a cabo con el fin de reducir su índice glicémico,
sin embargo, aún existe controversia sobre la acción de
la fibra dietética en la disminución del IG en este alimento.
Este estudio determinó el efecto de la fibra dietética sobre el
índice glicémico y carga glicémica en dos tipos de panes comerciales
en 23 individuos sanos quienes consumieron aleatoriamente
3 diferentes productos, de 50 g de carbohidratos
cada uno, durante 6 días: pan blanco (PH), pan integral (PF),
y solución glucosada como producto de referencia (SG). Se
midió glicemia en ayunas y post-prandial a los tiempos 15,
30, 45, 60, 90 y 120 min. La insulina fue medida en el minuto
0 y 120 min. El área bajo la curva de glicemia resultó
más baja para ambos tipos de pan PH 13589 ±1557, PF
12005 ±1254 que para el producto de referencia SG 14089
±1245. Los valores del índice glicémico PH 68,55 ±1,2 y PF
62,10 ±1,3 y carga glicémica PH 16,45 ±1,4 resultaron más
bajos para el pan con mayor aporte de fibra 9,93 ± 1,1, sin
diferencias en la concentración de insulina, sugiriendo que
la cantidad de carbohidratos y tipo de fibra contenidos en el
pan integral, pueden considerarse factores intrínsecos en su
composición nutricional, capaces de afectar la respuesta glicémica
post- ingesta de estos productos en individuos sanos.There are several foods that contain carbohydrates as the
main nutrient, being one of the most important the bread for
its massive worldwide consumption. Numerous studies have
been done in order to reduce its glycemic index, however
there is still controversy about the action of dietary fiber in the
decrease of GI in this product. In this study, it was determined
the effect of dietetic fiber on glycemic index and glycemic load
in two types of commercial breads in 23 healthy individuals
who randomly consumed 3 different products during 6 days
of 50g of carbohydrates each: white bread (PH), whole wheat
bread (PE) and glucose solution as reference product (SG).
Fasting and postprandial glycemia was measured at times
15, 30, 45, 60, 90 and 120 minutes. Insuline was measured
at 0 min and 120 min. The area under de glycemia curve
was lower for both bread types PH 13589 ±1557, PF 12005
±1254 than for the reference product SG 14089 ±1245. The
values of the glycemic index PH 68,55 ±1,2 and PF 62,01
±1,3 and glycemic load PH 16.45 ±1,4 were lower for bread
with more amount fiber 9,93 ± 1,1, with no difference in insulin
concentration, suggesting that the amount of carbohydrates
and fiber type contained in whole wheat bread can
be considered intrinsic factors in bread composition, affecting
the post-intake glycemic response of this type of products in
healthy individuals.http://www.redalyc.org/articulo.oa?id=5594990800
The ALHAMBRA survey: Accurate merger fractions by PDF analysis of photometric close pairs
Our goal is to develop and test a novel methodology to compute accurate close
pair fractions with photometric redshifts. We improve the current methodologies
to estimate the merger fraction f_m from photometric redshifts by (i) using the
full probability distribution functions (PDFs) of the sources in redshift
space, (ii) including the variation in the luminosity of the sources with z in
both the selection of the samples and in the luminosity ratio constrain, and
(iii) splitting individual PDFs into red and blue spectral templates to deal
robustly with colour selections. We test the performance of our new methodology
with the PDFs provided by the ALHAMBRA photometric survey. The merger fractions
and rates from the ALHAMBRA survey are in excellent agreement with those from
spectroscopic work, both for the general population and for red and blue
galaxies. With the merger rate of bright (M_B <= -20 - 1.1z) galaxies evolving
as (1+z)^n, the power-law index n is larger for blue galaxies (n = 2.7 +- 0.5)
than for red galaxies (n = 1.3 +- 0.4), confirming previous results.
Integrating the merger rate over cosmic time, we find that the average number
of mergers per galaxy since z = 1 is N_m = 0.57 +- 0.05 for red galaxies and
N_m = 0.26 +- 0.02 for blue galaxies. Our new methodology exploits
statistically all the available information provided by photometric redshift
codes and provides accurate measurements of the merger fraction by close pairs
only using photometric redshifts. Current and future photometric surveys will
benefit of this new methodology.Comment: Submitted to A&A, 15 pages, 15 figures, 6 tables. Comments are
welcome. Close pair systems available at
https://cloud.iaa.csic.es/alhambra/catalogues/ClosePairs
High redshift galaxies in the ALHAMBRA survey: I. selection method and number counts based on redshift PDFs
Context. Most observational results on the high redshift restframe UV-bright
galaxies are based on samples pinpointed using the so called dropout technique
or Ly-alpha selection. However, the availability of multifilter data allows now
replacing the dropout selections by direct methods based on photometric
redshifts. In this paper we present the methodology to select and study the
population of high redshift galaxies in the ALHAMBRA survey data. Aims. Our aim
is to develop a less biased methodology than the traditional dropout technique
to study the high redshift galaxies in ALHAMBRA and other multifilter data.
Thanks to the wide area ALHAMBRA covers, we especially aim at contributing in
the study of the brightest, less frequent, high redshift galaxies. Methods. The
methodology is based on redshift probability distribution functions (zPDFs). It
is shown how a clean galaxy sample can be obtained by selecting the galaxies
with high integrated probability of being within a given redshift interval.
However, reaching both a complete and clean sample with this method is
challenging. Hence, a method to derive statistical properties by summing the
zPDFs of all the galaxies in the redshift bin of interest is introduced.
Results. Using this methodology we derive the galaxy rest frame UV number
counts in five redshift bins centred at z=2.5, 3.0, 3.5, 4.0, and 4.5, being
complete up to the limiting magnitude at m_UV(AB)=24. With the wide field
ALHAMBRA data we especially contribute in the study of the brightest ends of
these counts, sampling well the surface densities down to m_UV(AB)=21-22.
Conclusions. We show that using the zPDFs it is easy to select a clean sample
of high redshift galaxies. We also show that statistical analysis of the
properties of galaxies is better done using a probabilistic approach, which
takes into account both the incompleteness and contamination in a natural way.Comment: 16 pages, 11 figures; Accepted for A&A; language correcte
The ALHAMBRA survey : band luminosity function of quiescent and star-forming galaxies at by PDF analysis
Our goal is to study the evolution of the band luminosity function (LF)
since using ALHAMBRA data. We used the photometric redshift and the
band selection magnitude probability distribution functions (PDFs) of those
ALHAMBRA galaxies with mag to compute the posterior LF. We
statistically studied quiescent and star-forming galaxies using the template
information encoded in the PDFs. The LF covariance matrix in
redshift-magnitude-galaxy type space was computed, including the cosmic
variance. That was estimated from the intrinsic dispersion of the LF
measurements in the 48 ALHAMBRA sub-fields. The uncertainty due to the
photometric redshift prior is also included in our analysis. We modelled the LF
with a redshift-dependent Schechter function affected by the same selection
effects than the data. The measured ALHAMBRA LF at and the
evolving Schechter parameters both for quiescent and star-forming galaxies
agree with previous results in the literature. The estimated redshift evolution
of is and , and of is
and . The measured faint-end slopes are and . We find a significant
population of faint quiescent galaxies, modelled by a second Schechter function
with slope . We find a factor decrease in the
luminosity density of star-forming galaxies, and a factor
increase in the of quiescent ones since , confirming the continuous
build-up of the quiescent population with cosmic time. The contribution of the
faint quiescent population to increases from 3% at to 6% at .
The developed methodology will be applied to future multi-filter surveys such
as J-PAS.Comment: Accepted for publication in Astronomy and Astrophysics. 25 pages, 20
figures, 7 table
The ALHAMBRA survey : Estimation of the clustering signal encoded in the cosmic variance
The relative cosmic variance () is a fundamental source of
uncertainty in pencil-beam surveys and, as a particular case of count-in-cell
statistics, can be used to estimate the bias between galaxies and their
underlying dark-matter distribution. Our goal is to test the significance of
the clustering information encoded in the measured in the ALHAMBRA
survey. We measure the cosmic variance of several galaxy populations selected
with band luminosity at as the intrinsic dispersion in
the number density distribution derived from the 48 ALHAMBRA subfields. We
compare the observational with the cosmic variance of the dark
matter expected from the theory, . This provides an
estimation of the galaxy bias . The galaxy bias from the cosmic variance is
in excellent agreement with the bias estimated by two-point correlation
function analysis in ALHAMBRA. This holds for different redshift bins, for red
and blue subsamples, and for several band luminosity selections. We find
that increases with the band luminosity and the redshift, as expected
from previous work. Moreover, red galaxies have a larger bias than blue
galaxies, with a relative bias of . Our results
demonstrate that the cosmic variance measured in ALHAMBRA is due to the
clustering of galaxies and can be used to characterise the affecting
pencil-beam surveys. In addition, it can also be used to estimate the galaxy
bias from a method independent of correlation functions.Comment: Astronomy and Astrophysics, in press. 9 pages, 4 figures, 3 table
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