121 research outputs found
On the shape factor of interaction laws for a non-local approximation of the Sobolev norm and the total variation
We consider the family of non-local and non-convex functionals introduced by
H. Brezis and H.-M. Nguyen in a recent paper. These functionals Gamma-converge
to a multiple of the Sobolev norm or the total variation, depending on a
summability exponent, but the exact values of the constants are unknown in many
cases.
We describe a new approach to the Gamma-convergence result that leads in some
special cases to the exact value of the constants, and to the existence of
smooth recovery families.Comment: Compte-rendu that summarizes the strategy developed in
ArXiv:1708.01231 and ArXiv:1712.04413. This version extends the previous one
keeping into account the changes in the above papers. 9 page
The assessment of hemineglect syndrome with cancellation tasks. A comparison between the bells test and the Apples test
Unilateral spatial neglect (USN) is a frequent consequence of acquired brain injury, especially following right hemisphere damage. Traditionally, unilateral spatial neglect is assessed with cancellation tests such as the Bells test. Recently, a new cancellation test, the Apples test, has been proposed. The present study aims at comparing the accuracy of these two tests in detecting hemispatial neglect, on a sample of 56 right hemisphere stroke patients with a diagnosis of USN. In order to evaluate the agreement between the Apples and Bells tests, Cohen's kappa and McNemar's test were used to assess differences between the two methods of evaluation. Poor agreement and statistically significant differences emerged between the Apples and Bells tests. Overall, the Apples test was significantly more sensitive than the Bells test in detecting USN. Based on these results, the use of the Apples test for peripersonal neglect assessment is therefore highly recommende
Autism Spectrum Disorders: Is Mesenchymal Stem Cell Personalized Therapy the Future?
Autism and autism spectrum disorders (ASDs) are heterogeneous neurodevelopmental disorders. They are enigmatic conditions that have their origins in the interaction of genes and environmental factors. ASDs are characterized by dysfunctions in social interaction and communication skills, in addition to repetitive and stereotypic verbal and nonverbal behaviours. Immune dysfunction has been confirmed with autistic children. There are no defined mechanisms of pathogenesis or curative therapy presently available. Indeed, ASDs are still untreatable. Available treatments for autism can be divided into behavioural, nutritional, and medical approaches, although no defined standard approach exists. Nowadays, stem cell therapy represents the great promise for the future of molecular medicine. Among the stem cell population, mesenchymal stem cells (MSCs) show probably best potential good results in medical research. Due to the particular immune and neural dysregulation observed in ASDs, mesenchymal stem cell transplantation could offer a unique tool to provide better resolution for this disease
Ranolazine Attenuates Trastuzumab-Induced Heart Dysfunction by Modulating ROS Production
The ErbB2 blocker trastuzumab improves survival in oncologic patients, but can cause cardiotoxicity. The late Na+ current inhibitor ranolazine has been shown to counter experimental HF, including doxorubicin cardiotoxicity (a condition characterized by derangements in redox balance), by lowering the levels of reactive oxygen species (ROS). Since ErbB2 can modulate ROS signaling, we tested whether trastuzumab cardiotoxicity could be blunted by ranolazine via redox-mediated mechanisms. Trastuzumab decreased fractional shortening and ejection fraction in mice, but ranolazine prevented heart dysfunction when co-administered with trastuzumab. Trastuzumab cardiotoxicity was accompanied by elevations in natriuretic peptides and matrix metalloproteinase 2 (MMP2) mRNAs, which were not elevated with co-treatment with ranolazine. Trastuzumab also increased cleavage of caspase-3, indicating activation of the proapoptotic machinery. Again, ranolazine prevented this activation. Interestingly, Neonatal Rat Ventricular Myocytes (NRVMs), labeled with MitoTracker Red and treated with trastuzumab, showed only a small increase in ROS compared to baseline conditions. We then stressed trastuzumab-treated cells with the beta-agonist isoproterenol to increase workload, and we observed a significant increase of probe fluorescence, compared with cells treated with isoproterenol alone, reflecting induction of oxidative stress. These effects were blunted by ranolazine, supporting a role for INa inhibition in the regulation of redox balance also in trastuzumab cardiotoxicity
A Search for H2O Megamasers in High-z Type-2 AGNs
We report a search for H2O megamasers in 274 SDSS type-2 AGNs (0.3 < z <
0.83), half of which can be classified as type-2 QSOs from their [OIII] 5007
luminosity, using the Robert C. Byrd Green Bank Telescope (GBT) and the
Effelsberg 100-m radio telescope. Apart from the detection of the extremely
luminous water vapor megamaser SDSS J080430.99+360718.1, already reported by
Barvainis & Antonucci (2005), we do not find any additional line emission. This
high rate of non-detections is compared to the water maser luminosity function
created from the 78 water maser galaxies known to date and its extrapolation
towards the higher luminosities of "gigamasers" that we would have been able to
detect given the sensitivity of our survey. The properties of the known water
masers are summarized and discussed with respect to the nature of high-z type-2
AGNs and megamasers in general. In the appendix, we list 173 additional objects
(mainly radio galaxies, but also QSOs and galaxies) that were observed with the
GBT, the Effelsberg 100-m radio telescope, or Arecibo Observatory without
leading to the detection of water maser emission.Comment: 28 pages, 3 figures. Accepted for publication in the Astrophysical
Journa
Size and Structure of the Narrow-Line Region of Quasars
We have observed the narrow-line regions (NLRs) of the seven brightest
radio-quiet PG (or BQS) quasars (z < 0.5) with the Wide Field and Planetary
Camera 2 on board the Hubble Space Telescope (HST). Linear-ramp filters were
used to image the [OIII] lambda 5007 line emission with 0.0455-0.1 arcsec pixel
resolution. We find that the NLRs are very compact with typical extents of 2-4
arcsec. Two quasars show compact filamentary structures similar to Seyfert
NLRs. They may be related to radio outflows. Most interestingly, when including
a sample of Seyfert galaxies observed with HST, we tentatively find that the
size of the NLR is proportional to the square root of the [OIII] luminosity.
This is comparable to the scaling found for the size of the broad-line region
with continuum luminosity, which has been interpreted in terms of a constant
photoionization parameter. The relation determined here connects the NLR of
radio-quiet quasars and Seyferts over three orders of magnitude in [OIII]
luminosity.Comment: 6 pages, 4 figures, accepted for publication in ApJ Letter
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