143 research outputs found
Sistema de realitat virtual per entrenament en laparoscopia
El proyecto está compuesto por un software y un joystick que ayudan a los cirujanos a entrenarse en operaciones de laparoscopia.
Se ha desarrollado un programa que rapresente a pantalla una cuerda virtual que se pueda manejar mediante en joystick.
Este es el primer modulo de un programa de entrenamiento mas compejo: hasta ahora el cirujano puede manejar y soltar la cuerda
de manera realista pero no hay ejercicios implementados aun
A magnetar powering the ordinary monster GRB 130427A?
We present the analysis of the extraordinarily bright Gamma-Ray Burst (GRB)
130427A under the hypothesis that the GRB central engine is an
accretion-powered magnetar. In this framework, initially proposed to explain
GRBs with precursor activity, the prompt emission is produced by accretion of
matter onto a newly-born magnetar, and the observed power is related to the
accretion rate. The emission is eventually halted if the centrifugal forces are
able to pause accretion. We show that the X-ray and optical afterglow is well
explained as the forward shock emission with a jet break plus a contribution
from the spin-down of the magnetar. Our modelling does not require any
contribution from the reverse shock, that may still influence the afterglow
light curve at radio and mm frequencies, or in the optical at early times. We
derive the magnetic field ( G) and the spin period (
ms) of the magnetar and obtain an independent estimate of the minimum
luminosity for accretion. This minimum luminosity results well below the prompt
emission luminosity of GRB 130427A, providing a strong consistency check for
the scenario where the entire prompt emission is the result of continuous
accretion onto the magnetar. This is in agreement with the relatively long spin
period of the magnetar. GRB 130427A was a well monitored GRB showing a very
standard behavior and, thus, is a well-suited benchmark to show that an
accretion-powered magnetar gives a unique view of the properties of long GRBs.Comment: 5 pages, 1 figure, accepted for publication in MNRAS Letter
Dipole-Coupled Neutrissimo Explanations of the MiniBooNE Excess Including Constraints from MINERvA Data
We revisit models of heavy neutral leptons (neutrissimos) with transition
magnetic moments as explanations of the excess of electron-like
events at MiniBooNE. We perform a detailed Monte Carlo-based analysis to
re-examine the preferred regions in the model parameter space to explain
MiniBooNE, considering also potential contributions from oscillations due to an
eV-scale sterile neutrino. We then derive robust constraints on the model using
neutrino-electron elastic scattering data from MINERvA. We find that MINERvA
rules out a large region of parameter space, but allowed solutions exist at the
confidence level. A dedicated MINERvA analysis would likely be able
to probe the entire region of preference of MiniBooNE in this model.Comment: 14 page
The Highly Energetic Expansion of SN2010bh Associated with GRB 100316D
We present the spectroscopic and photometric evolution of the nearby (z =
0.059) spectroscopically confirmed type Ic supernova, SN 2010bh, associated
with the soft, long-duration gamma-ray burst (X-ray flash) GRB 100316D.
Intensive follow-up observations of SN 2010bh were performed at the ESO Very
Large Telescope (VLT) using the X-shooter and FORS2 instruments. Owing to the
detailed temporal coverage and the extended wavelength range (3000--24800 A),
we obtained an unprecedentedly rich spectral sequence among the hypernovae,
making SN 2010bh one of the best studied representatives of this SN class. We
find that SN 2010bh has a more rapid rise to maximum brightness (8.0 +/- 1.0
rest-frame days) and a fainter absolute peak luminosity (L_bol~3e42 erg/s) than
previously observed SN events associated with GRBs. Our estimate of the ejected
(56)Ni mass is 0.12 +/- 0.02 Msun. From the broad spectral features we measure
expansion velocities up to 47,000 km/s, higher than those of SNe 1998bw (GRB
980425) and 2006aj (GRB 060218). Helium absorption lines He I lambda5876 and He
I 1.083 microm, blueshifted by ~20,000--30,000 km/s and ~28,000--38,000 km/s,
respectively, may be present in the optical spectra. However, the lack of
coverage of the He I 2.058 microm line prevents us from confirming such
identifications. The nebular spectrum, taken at ~186 days after the explosion,
shows a broad but faint [O I] emission at 6340 A. The light-curve shape and
photospheric expansion velocities of SN 2010bh suggest that we witnessed a
highly energetic explosion with a small ejected mass (E_k ~ 1e52 erg and M_ej ~
3 Msun). The observed properties of SN 2010bh further extend the heterogeneity
of the class of GRB supernovae.Comment: 37 pages and 12 figures (one-column pre-print format), accepted for
publication in Ap
Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation
The exploitation of the association between plants and microorganisms is a promising approach able to boost natural attenuation processes for soil clean-up in vast polluted areas characterized by mixed chemical contamination. We aimed to explore the selection of root-associated bacterial communities driven by different plant species spontaneously established in abandoned agricultural soils within a historical polluted site in north Italy. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobiphenyls (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. The overall structure of the non-vegetated and root-associated soil fractions bacterial communities was described by high-throughput sequencing of the 16S rRNA gene, and a collection of 165 rhizobacterial isolates able to use biphenyl as unique carbon source was assayed for plant growth promotion (PGP) traits and bioremediation potential. The results showed that the recruitment of specific bacterial communities in the root-associated soil fractions was driven by both soil fractions and plant species, explaining 21 and 18% of the total bacterial microbiome variation, respectively. PCR-based detection in the soil metagenome of bacterial bphA gene, encoding for the biphenyl dioxygenase ? subunit, indicated that the soil in the site possesses metabolic traits linked to PCB degradation. Biphenyl-utilizing bacteria isolated from the rhizosphere of the three different plant species showed low phylogenetic diversity and well represented functional traits, in terms of PGP and bioremediation potential. On average, 72% of the strains harbored the bphA gene and/or displayed catechol 2,3-dioxygenase activity, involved in aromatic ring cleavage. PGP traits, including 1-aminocyclopropane-1-carboxylic acid deaminase activity potentially associated to plant stress tolerance induction, were widely distributed among the isolates according to in vitro assays. PGP tested in vivo on tomato plants using eleven selected bacterial isolates, confirmed the promotion and protection potential of the rhizosphere bacteria. Different spontaneous plant species naturally selected in a historical chronically polluted site showed to determine the enrichment of peculiar bacterial communities in the soil fractions associated to the roots. All the rhizosphere communities, nevertheless, hosted bacteria with degradation/detoxification and PGP potential, putatively sustaining the natural attenuation process
Overexpression of microRNA-206 in the skeletal muscle from myotonic dystrophy type 1 patients
<p>Abstract</p> <p>Background</p> <p>MicroRNAs are highly conserved, noncoding RNAs involved in post-transcriptional gene silencing. They have been shown to participate in a wide range of biological processes, including myogenesis and muscle regeneration. The goal of this study is to test the hypothesis that myo-miRs (myo = muscle + miR = miRNA) expression is altered in muscle from patients affected by myotonic dystrophy type 1 (DM1), the most frequently inherited neuromuscular disease in adults. In order to gain better insights about the role of miRNAs in the DM1 pathogenesis, we have also analyzed the muscular expression of miR-103 and miR-107, which have been identified <it>in silico </it>as attractive candidates for binding to the <it>DMPK </it>mRNA.</p> <p>Methods</p> <p>To this aim, we have profiled the expression of miR-133 (miR-133a, miR-133b), miR-1, miR-181 (miR-181a, miR-181b, miR-181c) and miR-206, that are specifically induced during myogenesis in cardiac and skeletal muscle tissues. miR-103 and miR-107, highly expressed in brain, heart and muscle have also been included in this study. QRT-PCR experiments have been performed on RNA from vastus lateralis biopsies of DM1 patients (n = 7) and control subjects (n = 4). Results of miRNAs expression have been confirmed by Northern blot, whereas <it>in situ </it>hybridization technique have been performed to localize misexpressed miRNAs on muscle sections from DM1 and control individuals.</p> <p>Results</p> <p>Only miR-206 showed an over-expression in 5 of 7 DM1 patients (threshold = 2, fold change between 1.20 and 13.22, average = 5.37) compared to the control group. This result has been further confirmed by Northern blot analysis (3.37-fold overexpression, <it>R</it><sup>2 </sup>= 0.89). <it>In situ </it>hybridization localized miR-206 to nuclear site both in normal and DM1 tissues. Cellular distribution in DM1 tissues includes also the nuclear regions of centralized nuclei, with a strong signal corresponding to nuclear clumps.</p> <p>Conclusions</p> <p>This work provides, for the first time, evidences about miRNAs misexpression in DM1 muscle tissues, adding a new element in the pathogenesis of this complex genetic disease.</p
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