8,346 research outputs found
Chronic stress and impaired glutamate function elicit a depressive-like phenotype and common changes in gene expression in the mouse frontal cortex
Major depression might originate from both environmental and genetic risk factors. The environmental chronic mild stress (CMS) model mimics some environmental factors contributing to human depression and induces anhedonia and helplessness. Mice heterozygous for the synaptic vesicle protein (SVP) vesicular glutamate transporter 1 (VGLUT1) have been proposed as a genetic model of deficient glutamate function linked to depressive-like behaviour. Here, we aimed to identify, in these two experimental models, gene expression changes in the frontal cortex, common to stress and impaired glutamate function.
Both VGLUT1+/- and CMS mice showed helpless and anhedonic-like behavior. Microarray studies in VGLUT1+/- mice revealed regulation of genes involved in apoptosis, neurogenesis, synaptic transmission, protein metabolic process or learning and memory. In addition, RT-PCR studies confirmed gene expression changes in several glutamate, GABA, dopamine and serotonin neurotransmitter receptors. On the other hand, CMS affected the regulation of 147 transcripts, some of them involved in response to stress and oxidoreductase activity. Interestingly, 52 genes were similarly regulated in both models. Specifically, a dowregulation in genes that promote cell proliferation (Anapc7), cell growth (CsnK1g1), cell survival (Hdac3), inhibition of apoptosis (Dido1) was observed. Genes linked to cytoskeleton (Hspg2, Invs), psychiatric disorders (Grin1, MapK12) or an antioxidant enzyme (Gpx2) were also downregulated. Moreover, genes that inhibit the MAPK pathways (Dusp14), stimulate oxidative metabolism (Eif4a2) and enhance glutamate transmission (Rab8b) were upregulated.
We suggest that these genes could form part of the altered “molecular context” underlying depressive-like behaviour in animal models. The clinical relevance of these findings is discussed
The afterglow and kilonova of the short GRB 160821B
GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized
by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at
z=0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We
present X-ray, optical/nIR and radio observations of its counterpart and model
them with two distinct components of emission: a standard afterglow, arising
from the interaction of the relativistic jet with the surrounding medium, and a
kilonova, powered by the radioactive decay of the sub-relativistic ejecta.
Broadband modeling of the afterglow data reveals a weak reverse shock
propagating backward into the jet, and a likely jet-break at 3.5 d. This is
consistent with a structured jet seen slightly off-axis while expanding into a
low-density medium. Analysis of the kilonova properties suggests a rapid
evolution toward red colors, similar to AT2017gfo, and a low nIR luminosity,
possibly due to the presence of a long-lived neutron star. The global
properties of the environment, the inferred low mass (M_ej < 0.006 Msun) and
velocities (v > 0.05 c) of lanthanide-rich ejecta are consistent with a binary
neutron star merger progenitor.Comment: 14 pages, 6 figures, MNRAS, in press. Moderate revision, added Figure
5 and X-ray data to Table
Identification of circulating miRNA profiles that distinguish malignant pleural mesothelioma from lung adenocarcinoma
Accurate diagnosis of malignant pleura mesothelioma (MPM) is challenging. Differential diagnosis of MPM versus lung adenocarcinoma (AD) is particularly difficult, yet clinically important since the two neoplasias call for different treatment approaches. Circulating miRNA-profiling to identify miRNAs that can be used to distinguish MPM from AD has not been reported. We conducted a wide screening study of miRNA profiles in serum pools of MPM patients (N = 11), AD patients (N = 36), and healthy subjects (N = 45) to identify non-invasive biomarkers for differential diagnosis of MPM and AD, using deep sequencing. Sequencing
detected up to 300 known miRNAs and up to 25 novel miRNAs species in the serum samples. Among known miRNAs, 7 were upregulated in MPM and 12 were upregulated in AD compared to healthy controls. Of these, eight were distinctive for AD and three were unique for MPM. Direct comparison of the miRNA profiles for MPM and AD revealed differences in miRNA levels that could be useful for differential diagnosis. No differentially expressed novel miRNAs were found. Further bioinformatics analysis indicated that three upregulated miRNAs in MPM are associated with the p38 pathway. There are unique alterations in serum miRNAs in MPM and AD compared to healthy controls, as well as differences between MPM and AD profiles. Differing miRNA levels between MPM and AD may be useful for differential diagnosis. A potential association to p38 pathway of three upregulated miRNAs in MPM was revealed
Transition from Fireball to Poynting-flux-dominated Outflow in Three-Episode GRB 160625B
The ejecta composition is an open question in gamma-ray bursts (GRB) physics.
Some GRBs possess a quasi-thermal spectral component in the time-resolved
spectral analysis, suggesting a hot fireball origin. Others show a featureless
non-thermal spectrum known as the "Band" function, consistent with a
synchrotron radiation origin and suggesting that the jet is
Poynting-flux-dominated at the central engine and likely in the emission region
as well. There are also bursts showing a sub-dominant thermal component and a
dominant synchrotron component suggesting a likely hybrid jet composition. Here
we report an extraordinarily bright GRB 160625B, simultaneously observed in
gamma-rays and optical wavelengths, whose prompt emission consists of three
isolated episodes separated by long quiescent intervals, with the durations of
each "sub-burst" being 0.8 s, 35 s, and 212 s, respectively. Its high
brightness (with isotropic peak luminosity L
erg/s) allows us to conduct detailed time-resolved spectral analysis in each
episode, from precursor to main burst and to extended emission. The spectral
properties of the first two sub-bursts are distinctly different, allowing us to
observe the transition from thermal to non-thermal radiation between
well-separated emission episodes within a single GRB. Such a transition is a
clear indication of the change of jet composition from a fireball to a
Poynting-flux-dominated jet.Comment: Revised version reflecting the referees' comments. 27 pages, 11
figures, 5 tables. The final edited version will appear in Nature Astronom
Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower of La_{0.6}Y_{0.1}Ca_{0.3}MnO_3
The magneto-thermoelectric power (TEP) of perovskite type
manganise oxide is found to exhibit a sharp peak
at some temperature . By approximating the true shape of the
measured magneto-TEP in the vicinity of by a linear triangle of the
form , we observe that . We adopt the electron localization scenario and
introduce a Ginzburg-Landau (GL) type theory which incorporates the two
concurrent phase transitions, viz., the paramagnetic-ferromagnetic transition
at the Curie point and the "metal-insulator" (M-I) transition at
. The latter is characterized by the divergence of the field-dependent
charge carrier localization length at some characteristic field
. Calculating the average and fluctuation contributions to the total
magnetization and the transport entropy related magneto-TEP
within the GL theory, we obtain a simple relationship between and the
above two critical temperatures ( and ). The observed slope
ratio is found to be governed by the competition between
the electron-spin exchange and the induced magnetic energy . The
comparison of our data with the model predictions produce ,
, , , and for the estimates of
the Curie temperature, the exchange coupling constant, the critical
magnetization, the localization length, and the free-to-localized carrier
number density ratio, respectively.Comment: 6 pages (REVTEX), 2 PS figures (epsf.sty); submitted to Phys.Rev.
ALMA Long Baseline Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z=3.042
We present initial results of very high resolution Atacama Large
Millimeter/submillimeter Array (ALMA) observations of the =3.042
gravitationally lensed galaxy HATLAS J090311.6+003906 (SDP.81). These
observations were carried out using a very extended configuration as part of
Science Verification for the 2014 ALMA Long Baseline Campaign, with baselines
of up to 15 km. We present continuum imaging at 151, 236 and 290 GHz, at
unprecedented angular resolutions as fine as 23 milliarcseconds (mas),
corresponding to an un-magnified spatial scale of ~180 pc at z=3.042. The ALMA
images clearly show two main gravitational arc components of an Einstein ring,
with emission tracing a radius of ~1.5". We also present imaging of CO(10-9),
CO(8-7), CO(5-4) and H2O line emission. The CO emission, at an angular
resolution of ~170 mas, is found to broadly trace the gravitational arc
structures but with differing morphologies between the CO transitions and
compared to the dust continuum. Our detection of H2O line emission, using only
the shortest baselines, provides the most resolved detection to date of thermal
H2O emission in an extragalactic source. The ALMA continuum and spectral line
fluxes are consistent with previous Plateau de Bure Interferometer and
Submillimeter Array observations despite the impressive increase in angular
resolution. Finally, we detect weak unresolved continuum emission from a
position that is spatially coincident with the center of the lens, with a
spectral index that is consistent with emission from the core of the foreground
lensing galaxy.Comment: 9 pages, 5 figures and 3 tables, accepted for publication in the
Astrophysical Journal Letter
First Results from High Angular Resolution ALMA Observations Toward the HL Tau Region
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations
from the 2014 Long Baseline Campaign in dust continuum and spectral line
emission from the HL Tau region. The continuum images at wavelengths of 2.9,
1.3, and 0.87 mm have unprecedented angular resolutions of 0.075 arcseconds (10
AU) to 0.025 arcseconds (3.5 AU), revealing an astonishing level of detail in
the circumstellar disk surrounding the young solar analogue HL Tau, with a
pattern of bright and dark rings observed at all wavelengths. By fitting
ellipses to the most distinct rings, we measure precise values for the disk
inclination (46.72pm0.05 degrees) and position angle (+138.02pm0.07 degrees).
We obtain a high-fidelity image of the 1.0 mm spectral index (), which
ranges from in the optically-thick central peak and two
brightest rings, increasing to 2.3-3.0 in the dark rings. The dark rings are
not devoid of emission, we estimate a grain emissivity index of 0.8 for the
innermost dark ring and lower for subsequent dark rings, consistent with some
degree of grain growth and evolution. Additional clues that the rings arise
from planet formation include an increase in their central offsets with radius
and the presence of numerous orbital resonances. At a resolution of 35 AU, we
resolve the molecular component of the disk in HCO+ (1-0) which exhibits a
pattern over LSR velocities from 2-12 km/s consistent with Keplerian motion
around a ~1.3 solar mass star, although complicated by absorption at low
blue-shifted velocities. We also serendipitously detect and resolve the nearby
protostars XZ Tau (A/B) and LkHa358 at 2.9 mm.Comment: 11 pages, 5 figures, 2 tables, accepted for publication in the
Astrophysical Journal Letter
ALMA Observations of Asteroid 3 Juno at 60 Kilometer Resolution
We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm
continuum images of the asteroid 3 Juno obtained with an angular resolution of
0.042 arcseconds (60 km at 1.97 AU). The data were obtained over a single 4.4
hr interval, which covers 60% of the 7.2 hr rotation period, approximately
centered on local transit. A sequence of ten consecutive images reveals
continuous changes in the asteroid's profile and apparent shape, in good
agreement with the sky projection of the three-dimensional model of the
Database of Asteroid Models from Inversion Techniques. We measure a geometric
mean diameter of 259pm4 km, in good agreement with past estimates from a
variety of techniques and wavelengths. Due to the viewing angle and inclination
of the rotational pole, the southern hemisphere dominates all of the images.
The median peak brightness temperature is 215pm13 K, while the median over the
whole surface is 197pm15 K. With the unprecedented resolution of ALMA, we find
that the brightness temperature varies across the surface with higher values
correlated to the subsolar point and afternoon areas, and lower values beyond
the evening terminator. The dominance of the subsolar point is accentuated in
the final four images, suggesting a reduction in the thermal inertia of the
regolith at the corresponding longitudes, which are possibly correlated to the
location of the putative large impact crater. These results demonstrate ALMA's
potential to resolve thermal emission from the surface of main belt asteroids,
and to measure accurately their position, geometric shape, rotational period,
and soil characteristics.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in the
Astrophysical Journal Letter
Oscillatory Exchange Coupling and Positive Magnetoresistance in Epitaxial Oxide Heterostructures
Oscillations in the exchange coupling between ferromagnetic
layers with paramagnetic spacer layer
thickness has been observed in epitaxial heterostructures of the two oxides.
This behavior is explained within the RKKY model employing an {\it ab initio}
calculated band structure of , taking into account strong electron
scattering in the spacer. Antiferromagnetically coupled superlattices exhibit a
positive current-in-plane magnetoresistance.Comment: 4 pages (RevTeX), 5 figures (EPS
Development of a nursing intervention to facilitate optimal antiretroviral-treatment taking among people living with HIV
<p>Abstract</p> <p>Background</p> <p>Failure by a large portion of PLHIV to take optimally ARV treatment can have serious repercussions on their health. The absence of a systematic treatment-taking promotion program in Quebec prompted stakeholders to develop jointly a theory- and evidence-based nursing intervention to this end. This article describes the results of a collective effort by researchers, clinicians and PLHIV to share their knowledge and create an appropriate intervention.</p> <p>Methods</p> <p>Intervention mapping was used as the framework for developing the intervention. First, the target population and environmental conditions were analyzed and a literature review conducted to identify predictors of optimal treatment taking. The predictors to emerge were self-efficacy and attitudes. Performance objectives were subsequently defined and crossed-referenced with the predictors to develop a matrix of change objectives. Then, theories of self-efficacy and persuasion (the predictors to emerge from step 1), together with practical strategies derived from these theories, were used to design the intervention. Finally, the sequence and content of the intervention activities were defined and organized, and the documentary material designed.</p> <p>Results</p> <p>The intervention involves an intensive, personalized follow-up over four direct-contact sessions, each lasting 45–75 minutes. Individuals are engaged in a learning process that leads to the development of skills to motivate themselves to follow the therapeutic plan properly, to overcome situations that make taking the antiretroviral medication difficult, to cope with side-effects, to relate to people in their social circle, and to deal with health professionals.</p> <p>Conclusion</p> <p>The intervention was validated by various health professionals and pre-tested with four PLHIV. Preliminary results support the suitability and viability of the intervention. A randomized trial is currently underway to verify the effectiveness of the intervention in promoting optimal antiretroviral treatment taking.</p
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