1,541 research outputs found
A giant radio halo in the low luminosity X-ray cluster Abell 523
Radio halos are extended and diffuse non-thermal radio sources present at the
cluster center, not obviously associated with any individual galaxy. A strong
correlation has been found between the cluster X-ray luminosity and the halo
radio power. We observe and analyze the diffuse radio emission present in the
complex merging structure Abell 523, classified as a low luminosity X-ray
cluster, to discuss its properties in the context of the halo total radio power
versus X-ray luminosity correlation. We reduced VLA archive observations at 1.4
GHz to derive a deep radio image of the diffuse emission, and compared radio,
optical, and X-ray data. Low-resolution VLA images detect a giant radio halo
associated with a complex merging region. The properties of this new halo agree
with those of radio halos in general discussed in the literature, but its radio
power is about a factor of ten higher than expected on the basis of the cluster
X-ray luminosity. Our study of this giant radio source demonstrates that radio
halos can also be present in clusters with a low X-ray luminosity. Only a few
similar cases have so far been found . This result suggests that this source
represent a new class of objects, that cannot be explained by classical radio
halo models. We suggest that the particle reacceleration related to merging
processes is very efficient and/or the X-ray luminosity is not a good indicator
of the past merging activity of a cluster.Comment: 5 pages, 6 figures, Astronomy and Astrophysics Letter in pres
Effects of Ti6Al4V mechanical and thermal surface modification on the adhesion of a chitosan-bioactive glass coating
Biomedical implants interact with human tissues introducing significant perturbation into the body. Implant surfaces can be then functionalized enabling better biocompatibility. At the same time, the additional use of a coating provides further functions such as corrosion protection, osteointegration, and drug delivery. In this context, a composite made of chitosan and bioactive glass nanoparticles has been used for coating Ti6Al4V alloy samples processed beforehand using different processes, i.e., polishing, milling, grit blasting, and electrical discharge machining. Experiments have been carried out to correlate substrate surface conditions and coating effectiveness in terms of scratch resistance with the final aim to obtain suitable guidelines to improve substrate-coating performances
Triple positive breast cancer. A distinct subtype?
Breast cancer is a heterogeneous disease, and within the HER-2 positive subtype this is highly exemplified by the presence of substantial phenotypical and clinical heterogeneity, mostly related to hormonal receptor (HR) expression. It is well known how HER-2 positivity is commonly associated with a more aggressive tumor phenotype and decreased overall survival and, moreover, with a reduced benefit from endocrine treatment. Preclinical studies corroborate the role played by functional crosstalks between HER-2 and estrogen receptor (ER) signaling in endocrine resistance and, more recently, the activation of ER signaling is emerging as a possible mechanism of resistance to HER-2 blocking agents. Indeed, HER-2 positive breast cancer heterogeneity has been suggested to underlie the variability of response not only to endocrine treatments, but also to HER-2 blocking agents. Among HER-2 positive tumors, HR status probably defines two distinct subtypes, with dissimilar clinical behavior and different sensitivity to anticancer agents. The triple positive subtype, namely, ER/PgR/Her-2 positive tumors, could be considered the subset which most closely resembles the HER-2 negative/HR positive tumors, with substantial differences in biology and clinical outcome. We argue on whether in this subgroup the "standard" treatment may be considered, in selected cases, i.e., small tumors, low tumor burden, high expression of both hormonal receptors, an overtreatment. This article review the existing literature on biologic and clinical data concerning the HER-2/ER/PgR positive tumors, in an attempt to better define the HER-2 subtypes and to optimize the use of HER-2 targeted agents, chemotherapy and endocrine treatments in the various subsets
Effectiveness of an innovative sensory approach to improve children’s nutritional choices
A case-control study was conducted to investigate the effectiveness of the Edueat® Method, through experiential workshops focused on the use of all 5 senses. In two different primary schools in the same city, questionnaires were administered in two months with a follow-up one year later. Participants: 119 children (age 8.2–9.0) chosen randomly; control group 66 (55.5%). Seven lessons of 2 h each were held in the schools by experts of the Edueat® method and seven extra lessons by the teachers. The main outcome measures were the children’s changes in their approach and attitude towards their eating habits. The answers were grouped with factor analysis and summarized through scores. Repeated-measures analysis of variance was conducted in order to identify the relationships between scores and treatment over time. At the end of treatment, the intervention group showed a significant appreciation towards healthy foods (+4.15 vs. −0.05, p = 0.02) and a greater capacity in identifying foods which are very good for the health (+15.6 vs. +14.4, p = 0.02). In conclusion, the Edueat® method was found to be particularly promising in transmitting knowledge of those foods which are healthy. Greater involvement of teachers and parents is crucial
Neurokinin 1 receptor antagonism requires norepinephrine to increase serotonin function
The present studies examined the role of norepinephrine (NE) system in mediating the enhancement of 5-HT function produced by neurokinin (NK)1 receptor antagonism. Dorsal raphe 5-HT and locus coeruleus NE neurons were recorded in vivo in mice lacking NK1 receptors in wildtype mice pretreated with the NK1 antagonist RP67580 and its inactive enantiomer RP 68651. RP67580 and RP68651 were also tested on 5-HT neurons of mice lacking the 5-HT(1A) receptor. RP67580 increased the firing rate of 5-HT neurons in wildtype mice and in 5-HT(1A) null mutant mice to the same degree, thus indicating that the mechanism by which NK1 antagonists enhances 5-HT firing is independent of 5-HT(1A) receptors. NE neuronal burst activity was increased in NK1 null mutant and wildtype mice given RP67580, but not with RP68651. After NE depletion, RP67580 was ineffective in increasing 5-HT neuronal firing activity in NK1 wildtype mice, and the enhancement of 5-HT neuronal firing observed in NK1 null mutant mice was abolished. In conclusion, NE neurons are essential for the action of NK1 antagonists on 5-HT neurons. In addition, the desensitization of 5-HT(1A) autoreceptors produced by NK1 receptor antagonism is not critical for enhancing 5-HT neuronal firing
From Cannabis sativa to Cannabidiol: Promising Therapeutic Candidate for the Treatment of Neurodegenerative Diseases
Cannabis sativa, commonly known as marijuana, contains a pool of secondary plant metabolites with therapeutic effects. Besides Δ9-tetrahydrocannabinol that is the principal psychoactive constituent of Cannabis, cannabidiol (CBD) is the most abundant nonpsychoactive phytocannabinoid and may represent a prototype for anti-inflammatory drug development for human pathologies where both the inflammation and oxidative stress (OS) play an important role to their etiology and progression. To this regard, Alzheimer's disease (AD), Parkinson's disease (PD), the most common neurodegenerative disorders, are characterized by extensive oxidative damage to different biological substrates that can cause cell death by different pathways. Most cases of neurodegenerative diseases have a complex etiology with a variety of factors contributing to the progression of the neurodegenerative processes; therefore, promising treatment strategies should simultaneously target multiple substrates in order to stop and/or slow down the neurodegeneration. In this context, CBD, which interacts with the eCB system, but has also cannabinoid receptor-independent mechanism, might be a good candidate as a prototype for anti-oxidant drug development for the major neurodegenerative disorders, such as PD and AD. This review summarizes the multiple molecular pathways that underlie the positive effects of CBD, which may have a considerable impact on the progression of the major neurodegenerative disorders
The connection between radio halos and cluster mergers and the statistical properties of the radio halo population
We discuss the statistical properties of the radio halo population in galaxy
clusters. Radio bi-modality is observed in galaxy clusters: a fraction of
clusters host giant radio halos while the majority of clusters do not show
evidence of diffuse cluster-scale radio emission. The radio bi-modality has a
correspondence in terms of dynamical state of the hosting clusters showing that
merging clusters host radio halos and follow the well known radio--X-ray
correlation, while more relaxed clusters do not host radio halos and populate a
region well separated from that correlation. These evidences can be understood
in the framework of a scenario where merger-driven turbulence re-accelerate the
radio emitting electrons. We discuss the main statistical expectations of this
scenario underlining the important role of upcoming LOFAR surveys to test
present models.Comment: 11 pages, 2 figures, Invited talk at the conference "Diffuse
Relativistic Plasmas", Bangalore, 1-4 March 2011; accepted for publication in
the Journal of Astrophysics and Astronom
Cannabinoid receptor agonist WIN 55,212-2 inhibits rat cortical dialysate gamma-aminobutyric acid levels
The effects of the cannabinoid receptor agonist WIN 55,212-2 (0.1-5 mg/kg i.p.) on endogenous extracellular gamma-aminobutyric acid (GABA) levels in the cerebral cortex of the awake rat was investigated by using microdialysis. WIN 55,212-2 (1 and 5 mg/kg i.p.) was associated with a concentration-dependent decrease in dialysate GABA levels (-16% +/- 4% and -26% +/- 4% of basal values, respectively). The WIN 55,212-2 (5 mg/kg i.p.) induced-inhibition was counteracted by a dose (0.1 mg/kg i.p.) of the CB(1) receptor antagonist SR141716A, which by itself was without effect on cortical GABA levels. These findings suggest that cannabinoids decrease cortical GABA levels in vivo, an action that might underlie some of the cognitive and behavioral effects of acute exposure to marijuana
Constrained Simulations of the Magnetic Field in the Local Universe and the Propagation of UHECRs
We use simulations of LSS formation to study the build-up of magnetic fields
(MFs) in the ICM. Our basic assumption is that cosmological MFs grow in a MHD
amplification process driven by structure formation out of a seed MF present at
high z. Our LCDM initial conditions for the density fluctuations have been
statistically constrained by the observed galaxies, based on the IRAS 1.2-Jy
all-sky redshift survey. As a result, prominent galaxy clusters in our
simulation coincide closely with their real counterparts. We find excellent
agreement between RMs of our simulated clusters and observational data. The
improved resolution compared to previous work also allows us to study the MF in
large-scale filaments, sheets and voids. By tracing the propagation of UHE
protons in the simulated MF we construct full-sky maps of expected deflection
angles of protons with arrival energies E=1e20eV and 4e19eV, respectively.
Strong deflections are only produced if UHE protons cross clusters, however
covering only a small area on the sky. Multiple crossings of sheets and
filaments over larger distances may give rise to noticeable deflections,
depending on the model adopted for the magnetic seed field. Based on our
results we argue that over a large fraction of the sky the deflections are
likely to remain smaller than the present experimental angular sensitivity.
Therefore, we conclude that forthcoming air shower experiments should be able
to locate sources of UHE protons and shed more light on the nature of
cosmological MFs.Comment: 3revised version, JCAP, accepte
Body mass index in HER2-negative metastatic breast cancer treated with first-line paclitaxel and bevacizumab
The evidence emerged from the TOURANDOT trial encourages evaluating the role of anthropometric determinants on treatment outcomes in HER2-negative metastatic breast cancer patients treated with bevacizumab-including regimens. We thus analyzed data from a subgroup of these patients from a larger cohort previously assessed for treatment outcomes. Patients were included in the present analysis if body mass index values had been recorded at baseline. Clinical benefit rates, progression free survival and overall survival were assessed for the overall study population and subgroups defined upon molecular subtype. One hundred ninety six patients were included (N:196). Body mass index showed no impact on clinical benefit rates in the overall study sample and in the luminal cancer subset (p = 0.12 and p = 0.79, respectively), but did so in the triple negative subgroup, with higher rates in patients with body mass index ≥25 (p = 0.03). In the overall study sample, body mass index did no impact progression free or overall survival (p = 0.33 and p = 0.67, respectively). Conversely, in triple negative patients, progression free survival was significantly longer with body mass index ≥25 (6 vs 14 months, p = 0.04). In this subset, overall survival was more favorable (25 vs 19 months, p = 0.02). The impact of the molecular subtype was confirmed in multivariate models including the length of progression free survival, and number of metastatic sites (p < 0.0001). Further studies are warranted to confirm our findings in more adequately sized, ad hoc, prospective studies
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