2,544 research outputs found
Utility of patient-derived lymphoblastoid cell lines as an ex vivo capecitabine sensitivity prediction model for breast cancer patients.
Capecitabine is commonly used in treating breast cancer; however, therapeutic response varies among patients and there is no clinically validated model to predict individual outcomes. Here, we investigated whether drug sensitivity quantified in ex vivo patients' blood-derived cell lines can predict response to capecitabine in vivo. Lymphoblastoid cell lines (LCLs) were established from a cohort of metastatic breast cancer patients (n = 53) who were prospectively monitored during treatment with single agent capecitabine at 2000 mg/m2/day. LCLs were treated with increasing concentrations of 5'-DFUR, a major capecitabine metabolite, to assess patients' ex vivo sensitivity to this drug. Subsequently, ex vivo phenotype was compared to observed patient disease response and drug induced-toxicities. We acquired an independent cohort of breast cancer cell lines and LCLs derived from the same donors from ATCC, compared their sensitivity to 5'-DFUR. As seen in the patient population, we observed large inter-individual variability in response to 5'-DFUR treatment in patient-derived LCLs. Patients whose LCLs were more sensitive to 5'-DFUR had a significantly longer median progression free survival (9-month vs 6-month, log rank p-value = 0.017). In addition, this significant positive correlation for 5'-DFUR sensitivity was replicated in an independent cohort of 8 breast cancer cell lines and LCLs derived from the same donor. Our data suggests that at least a portion of the individual sensitivity to capecitabine is shared between germline tissue and tumor tissue. It also supports the utility of patient-derived LCLs as a predictive model for capecitabine treatment efficacy in breast cancer patients
Characterizing SL2S galaxy groups using the Einstein radius
We analyzed the Einstein radius, , in our sample of SL2S galaxy
groups, and compared it with (the distance from the arcs to the center of
the lens), using three different approaches: 1.- the velocity dispersion
obtained from weak lensing assuming a Singular Isothermal Sphere profile
(), 2.- a strong lensing analytical method ()
combined with a velocity dispersion-concentration relation derived from
numerical simulations designed to mimic our group sample, 3.- strong lensing
modeling () of eleven groups (with four new models presented in
this work) using HST and CFHT images. Finally, was analyzed as a function
of redshift to investigate possible correlations with L, N, and the
richness-to-luminosity ratio (N/L). We found a correlation between
and , but with large scatter. We estimate = (2.2 0.9)
+ (0.7 0.2), = (0.4 1.5) + (1.1
0.4), and = (0.4 1.5) + (0.9 0.3) for
each method respectively. We found a weak evidence of anti-correlation between
and , with Log = (0.580.06) - (0.040.1), suggesting
a possible evolution of the Einstein radius with , as reported previously by
other authors. Our results also show that is correlated with L and N
(more luminous and richer groups have greater ), and a possible
correlation between and the N/L ratio. Our analysis indicates that
is correlated with in our sample, making useful to
characterize properties like L and N (and possible N/L) in galaxy groups.
Additionally, we present evidence suggesting that the Einstein radius evolves
with .Comment: Accepted for publication in Astronomy & Astrophysics. Typos correcte
Filaments in observed and mock galaxy catalogues
Context. The main feature of the spatial large-scale galaxy distribution is
an intricate network of galaxy filaments. Although many attempts have been made
to quantify this network, there is no unique and satisfactory recipe for that
yet. Aims. The present paper compares the filaments in the real data and in the
numerical models, to see if our best models reproduce statistically the
filamentary network of galaxies. Methods. We apply an object point process with
interactions (the Bisous process) to trace and describe the filamentary network
both in the observed samples (the 2dFGRS catalogue) and in the numerical models
that have been prepared to mimic the data.We compare the networks. Results. We
find that the properties of filaments in numerical models (mock samples) have a
large variance. A few mock samples display filaments that resemble the observed
filaments, but usually the model filaments are much shorter and do not form an
extended network. Conclusions. We conclude that although we can build numerical
models that are similar to observations in many respects, they may fail yet to
explain the filamentary structure seen in the data. The Bisous-built filaments
are a good test for such a structure.Comment: 13 pages, accepted for publication in Astronomy and Astrophysic
Parámetros de calidad de la canal y la carne de cabritos lechales de raza payoya en sistema de explotación convencional
En el trabajo se han elegido 24 cabritos pertenecientes a la raza Payoya,
12 machos y 12 hembras con el objeto de comparar los parámetros de la calidad de la canal y de la carne. Los resultados nos muestran que aunque existen algunas diferencias en algunas medidas de calidad de la carne (pH, CRA, L*, a*, b*, C y Hº), el resto de los parámetros estudiados no presentaron diferencias significativas entre los dos sexos
Bullying girls - Changes after brief strategic family therapy: A randomized, prospective, controlled trial with one-year follow-up
Background: Many girls bully others. They are conspicuous because of their risk-taking behavior, increased anger, problematic interpersonal relationships and poor quality of life. Our aim was to determine the efficacy of brief strategic family therapy (BSFT) for bullying-related behavior, anger reduction, improvement of interpersonal relationships, and improvement of health-related quality of life in girls who bully, and to find out whether their expressive aggression correlates with their distinctive psychological features. Methods: 40 bullying girls were recruited from the general population: 20 were randomly selected for 3 months of BSFT. Follow-up took place 12 months after the therapy had ended. The results of treatment were examined using the Adolescents' Risk-taking Behavior Scale (ARBS), the State-Trait Anger Expression Inventory (STAXI), the Inventory of Interpersonal Problems (IIP-D), and the SF-36 Health Survey (SF-36). Results: In comparison with the control group (CG) (according to the intent-to-treat principle), bullying behavior in the BSFT group was reduced (BSFT-G from n = 20 to n = 6; CG from n = 20 to n = 18, p = 0.05) and statistically significant changes in all risk-taking behaviors (ARBS), on most STAXI, IIP-D, and SF-36 scales were observed after BSFT. The reduction in expressive aggression (Anger-Out scale of the STAXI) correlated with the reduction on several scales of the ARBS, IIP-D, and SF-36. Follow-up a year later showed relatively stable events. Conclusions: Our findings suggest that bullying girls suffer from psychological and social problems which may be reduced by the use of BSFT. Expressive aggression in girls appears to correlate with several types of risk-taking behavior and interpersonal problems, as well as with health-related quality of life. Copyright (c) 2006 S. Karger AG, Basel
Scanned Probe Microscopy of Electronic Transport in Carbon Nanotubes
We use electrostatic force microscopy and scanned gate microscopy to probe
the conducting properties of carbon nanotubes at room temperature. Multi-walled
carbon nanotubes are shown to be diffusive conductors, while metallic
single-walled carbon nanotubes are ballistic conductors over micron lengths.
Semiconducting single-walled carbon nanotubes are shown to have a series of
large barriers to conduction along their length. These measurements are also
used to probe the contact resistance and locate breaks in carbon nanotube
circuits.Comment: 4 page
The Glial Regenerative Response to Central Nervous System Injury Is Enabled by Pros-Notch and Pros-NFκB Feedback
Organisms are structurally robust, as cells accommodate changes preserving structural integrity and function. The molecular mechanisms underlying structural robustness and plasticity are poorly understood, but can be investigated by probing how cells respond to injury. Injury to the CNS induces proliferation of enwrapping glia, leading to axonal re-enwrapment and partial functional recovery. This glial regenerative response is found across species, and may reflect a common underlying genetic mechanism. Here, we show that injury to the Drosophila larval CNS induces glial proliferation, and we uncover a gene network controlling this response. It consists of the mutual maintenance between the cell cycle inhibitor Prospero (Pros) and the cell cycle activators Notch and NFκB. Together they maintain glia in the brink of dividing, they enable glial proliferation following injury, and subsequently they exert negative feedback on cell division restoring cell cycle arrest. Pros also promotes glial differentiation, resolving vacuolization, enabling debris clearance and axonal enwrapment. Disruption of this gene network prevents repair and induces tumourigenesis. Using wound area measurements across genotypes and time-lapse recordings we show that when glial proliferation and glial differentiation are abolished, both the size of the glial wound and neuropile vacuolization increase. When glial proliferation and differentiation are enabled, glial wound size decreases and injury-induced apoptosis and vacuolization are prevented. The uncovered gene network promotes regeneration of the glial lesion and neuropile repair. In the unharmed animal, it is most likely a homeostatic mechanism for structural robustness. This gene network may be of relevance to mammalian glia to promote repair upon CNS injury or disease
Reactor mixing angle from hybrid neutrino masses
In terms of its eigenvector decomposition, the neutrino mass matrix (in the
basis where the charged lepton mass matrix is diagonal) can be understood as
originating from a tribimaximal dominant structure with small deviations, as
demanded by data. If neutrino masses originate from at least two different
mechanisms, referred to as "hybrid neutrino masses", the experimentally
observed structure naturally emerges provided one mechanism accounts for the
dominant tribimaximal structure while the other is responsible for the
deviations. We demonstrate the feasibility of this picture in a fairly
model-independent way by using lepton-number-violating effective operators,
whose structure we assume becomes dictated by an underlying flavor
symmetry. We show that if a second mechanism is at work, the requirement of
generating a reactor angle within its experimental range always fixes the solar
and atmospheric angles in agreement with data, in contrast to the case where
the deviations are induced by next-to-leading order effective operators. We
prove this idea is viable by constructing an -based ultraviolet
completion, where the dominant tribimaximal structure arises from the type-I
seesaw while the subleading contribution is determined by either type-II or
type-III seesaw driven by a non-trivial singlet (minimal hybrid model).
After finding general criteria, we identify all the symmetries
capable of producing such -based minimal hybrid models.Comment: 18 pages, 5 figures. v3: section including sum rules added, accepted
by JHE
The Millennium Run Observatory: First Light
Simulations of galaxy evolution aim to capture our current understanding as
well as to make predictions for testing by future experiments. Simulations and
observations are often compared in an indirect fashion: physical quantities are
estimated from the data and compared to models. However, many applications can
benefit from a more direct approach, where the observing process is also
simulated and the models are seen fully from the observer's perspective. To
facilitate this, we have developed the Millennium Run Observatory (MRObs), a
theoretical virtual observatory which uses virtual telescopes to `observe'
semi-analytic galaxy formation models based on the suite of Millennium Run dark
matter simulations. The MRObs produces data that can be processed and analyzed
using the standard software packages developed for real observations. At
present, we produce images in forty filters from the rest-frame UV to IR for
two stellar population synthesis models, three different models of IGM
absorption, and two cosmologies (WMAP1/7). Galaxy distributions for a large
number of mock lightcones can be `observed' using models of major ground- and
space-based telescopes. The data include lightcone catalogues linked to
structural properties of galaxies, pre-observation model images, mock telescope
images, and Source Extractor products that can all be traced back to the higher
level dark matter, semi-analytic galaxy, and lightcone catalogues available in
the Millennium database. Here, we describe our methods and announce a first
public release of simulated surveys (e.g., SDSS, CFHT-LS, GOODS, GOODS/ERS,
CANDELS, and HUDF). The MRObs browser, an online tool, further facilitates
exploration of the simulated data. We demonstrate the benefits of a direct
approach through a number of example applications (galaxy number counts in
CANDELS, clusters, morphologies, and dropout selections).Comment: MNRAS, in press. Millennium Run Observatory data products, online
tools, and more available through http://galformod.mpa-garching.mpg.de/mrobs
High temperature behaviour of CuO-based oxygen carriers for chemical-looping combustion process
El “Chemical Looping Combustion” (CLC) es una tecnología de combustión con separación inherente del CO2. Para
escalar el proceso se necesitan materiales aptos para trabajar a alta temperatura. Se ha probado que los transportadores
de base cobre cumplen los requerimientos, sin embargo se ha recomendado su trabajo a temperaturas menores de 1073
K. En este trabajo, se han desarrollado, por impregnación en diferentes soportes, dos transportadores basados en Cu.
Se estudió su comportamiento a temperaturas por encima de 1073K en una unidad de CLC de 500 Wth teniendo en
cuenta aspectos como: eficiencia de combustión, resistencia al desgaste, aglomeración, mantenimiento de la capacidad
de transporte de oxígeno y reactividad. Problemas de aglomeración o desactivación de las partículas no se detectaron con
ninguno de los TOs. Fue posible la operación estable durante más de 67 horas sólo con el TO modificado con la adición
de NiO como soporte. Esta es la primera vez que un TO de base cobre, preparado por un método de fabricación comercial,
se utiliza a 1173 K de temperatura en el reactor de reducción (TRR) y 1223 K en el de oxidación (TRO) y presenta buenas
propiedades, abriendo nuevas posibilidades para la aplicación de materiales a base de cobre en los procesos de CLC a
escala industrial. Abstract
Chemical-Looping Combustion (CLC) is a combustion technology with inherent CO2 separation. To scale up the CLC
process materials suitable to work at high temperatures are needed. Cu-based oxygen carriers had been proved to fulfil
the requirements although temperatures lower than 1073 K has been recommended. In this work, two Cu-based OCs
have been developed by impregnation on different supports. The behaviour of the OCs was studied at temperatures
above 1073K in a CLC continuous unit of 500 Wth taking into account aspects such as combustion efficiency, attrition,
agglomeration and maintenance of the oxygen transport capacity and reactivity. Agglomeration or deactivation of the
particles was never detected with neither of the oxygen carriers used. At these high temperatures, stable operation for
more than 67 h was feasible only using an OC with γAl2O3 modified with NiO addition as support. This is the first time
that a Cu-based OC, prepared by a commercial manufacturing method, and used at 1173 K of fuel reactor temperature
(TFR) and 1223 K of air reactor temperature (TAR) exhibits such a good properties. This result opens new possibilities
for the application of Cu-based materials in industrial-scale CLC processes
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