2,247 research outputs found
Flow over the Mid Adriatic Pit
The influence of the Mid Adriatic Pit (MAP) on the general circulation of the Adriatic is explored through numerical simulations. The numerical code used is the DieCAST model specifically modified for application to the Adriatic Sea. A ten-year simulation is performed and the ability of the model to capture important features of the Adriatic circulation is demonstrated. A series of numerical
experiments on the importance of the MAP on the general circulation is performed. It is demonstrated that the current over the northern flank of the MAP, which flows
from the Croatian toward the Italian coast, is primarily a topographic current and that such a current would reverse direction if the gradient of the bathymetry were
reversed
Flow over the Mid Adriatic Pit
The influence of the Mid Adriatic Pit (MAP) on the general circulation of the Adriatic is explored through numerical simulations. The numerical code used is the DieCAST model specifically modified for application to the Adriatic Sea. A ten-year simulation is performed and the ability of the model to capture important features of the Adriatic circulation is demonstrated. A series of numerical
experiments on the importance of the MAP on the general circulation is performed. It is demonstrated that the current over the northern flank of the MAP, which flows
from the Croatian toward the Italian coast, is primarily a topographic current and that such a current would reverse direction if the gradient of the bathymetry were
reversed
Isospin symmetry violation in mirror E1 transitions: Coherent contributions from the giant isovector monopole resonance in the 67As-67Se doublet
The assumption of an exact isospin symmetry would imply equal strengths for mirror E1 transitions (at least, in the long-wavelength limit). Actually, large violations of this symmetry rule have been indicated by a number of experimental results, the last of which is the 67As-67Se doublet investigated at GAMMASPHERE. Here, we examine in detail various possible origins of the observed asymmetry. The coherent effect of Coulomb-induced mixing with the high-lying giant isovector monopole resonance is proposed as the most probable process to produce a large asymmetry in the E1 transitions, with comparatively small effect on the other properties of the parent and daughter levels. © 2012 American Physical Society.Financial support from the Spanish Ministry of Economy and Competitiveness, via the Project Consolider Ingenio (CPAN) (CSD2007-42).Peer Reviewe
Energy minimizing maps with prescribed singularities and Gilbert-Steiner optimal networks
We investigate the relation between energy minimizing maps valued into spheres having topological singularities at given points and optimal networks connecting them (e.g., Steiner trees, Gilbert-Steiner irrigation networks). We show the equivalence of the corresponding variational problems, interpreting in particular the branched optimal transport problem as a homological Plateau problem for rectifiable currents with values in a suitable normed group. This generalizes the pioneering work by Brezis, Coron and Lieb [10]
Simbol-X Hard X-ray Focusing Mirrors: Results Obtained During the Phase A Study
Simbol-X will push grazing incidence imaging up to 80 keV, providing a strong
improvement both in sensitivity and angular resolution compared to all
instruments that have operated so far above 10 keV. The superb hard X-ray
imaging capability will be guaranteed by a mirror module of 100 electroformed
Nickel shells with a multilayer reflecting coating. Here we will describe the
technogical development and solutions adopted for the fabrication of the mirror
module, that must guarantee an Half Energy Width (HEW) better than 20 arcsec
from 0.5 up to 30 keV and a goal of 40 arcsec at 60 keV. During the phase A,
terminated at the end of 2008, we have developed three engineering models with
two, two and three shells, respectively. The most critical aspects in the
development of the Simbol-X mirrors are i) the production of the 100 mandrels
with very good surface quality within the timeline of the mission; ii) the
replication of shells that must be very thin (a factor of 2 thinner than those
of XMM-Newton) and still have very good image quality up to 80 keV; iii) the
development of an integration process that allows us to integrate these very
thin mirrors maintaining their intrinsic good image quality. The Phase A study
has shown that we can fabricate the mandrels with the needed quality and that
we have developed a valid integration process. The shells that we have produced
so far have a quite good image quality, e.g. HEW <~30 arcsec at 30 keV, and
effective area. However, we still need to make some improvements to reach the
requirements. We will briefly present these results and discuss the possible
improvements that we will investigate during phase B.Comment: 6 pages, 3 figures, invited talk at the conference "2nd International
Simbol-X Symposium", Paris, 2-5 december, 200
Contrast-enhanced ultrasound features of hepatocellular carcinoma in dogs
BACKGROUND:
This study aimed to describe the contrast-enhanced ultrasound (CEUS) features of canine hepatocellular carcinoma (HCC) in relation to cellular differentiation and lesion size.
METHODS: Sixty dogs with a cytological diagnosis of HCC and that underwent a CEUS examination were retrospectively selected. The wash-in and wash-out patterns of contrast enhancement, along with the time to wash-in and the time to wash-out, of each lesion were recorded. A dimensional cut-off value of 3\u2009cm was adopted for classification.
RESULTS: Cellular differentiation had a significant influence on both wash-in (chi-squared=16.99; P<0.001) and wash-out (chi-squared=10.9; P=0.004) patterns of contrast enhancement. Lesion size had a lower, but still significant, influence on both wash-in (chi-squared=12.7; P=0.005) and wash-out (chi-squared=7.42; P=0.024) patterns. A homogeneous hyperenhancement in the arterial phase followed by homogeneous wash-out were suggestive of a well-differentiated HCC. The cellular differentiation of lesions with inhomogeneous hyperenhancement or hypoenhancement/no enhancement as well as an inhomogeneous wash-out or no wash-out could not be inferred.
CONCLUSIONS: No significant difference in the time to wash-in and the time to wash-out in relation to cellular differentiation or lesion size was evident. CEUS has the potential to improve efficiency in the diagnosis of HCCs in dogs
Metronomic ceramide analogs inhibit angiogenesis in pancreatic cancer through up-regulation of caveolin-1 and thrombospondin-1 and down-regulation of cyclin D1
Aims. The aims of this study were to evaluate the antitumor and antiangiogenic activity of
metronomic ceramide analogs and to investigate their relevant molecular mechanisms.
Methods. Human endothelial cells (HMVEC-d, HUVEC) and pancreatic cancer cells (Capan-1,
MIAPaCa-2) were treated with the ceramide analogs (C2, AL6, C6 and C8), at low concentrations
for 144h to evaluate any antiproliferative and pro-apoptotic effects, inhibition of migration, and to
measure the expression of caveolin-1 (CAV-1) and thrombospondin-1 (TSP-1) mRNAs by real time
RT-PCR. Assessment of ERK1/2 and Akt phosphorylation, and of CAV-1 and cyclin-D1 protein
expression was performed by ELISA. Maximum tolerated dose (MTD) gemcitabine was compared
against metronomic doses of the ceramide analogs by evaluating the inhibition of MIAPaCA-2
subcutaneous tumor growth in nude mice.
Results. Metronomic ceramide analogs preferentially inhibited cell proliferation and enhanced
apoptosis in endothelial cells. Low concentrations of AL6 and C2 caused a significant inhibition of
HUVEC cell migration. ERK1/2 and Akt phosphorylation were significantly decreased after
metronomic ceramide analog treatment. Such treatment caused the over-expression of CAV-1 and
TSP-1 mRNA and protein in endothelial cells, whereas cyclin-D1 protein levels were reduced
significantly. The antiangiogenic and antitumor impact in vivo of metronomic C2 and AL6 regimens
was similar to that caused by MTD gemcitabine. C6 and C8 did not show any significant in vivo
antitumor effects.
Conclusions. Metronomic C2 and AL6 analogs have antitumor and antiangiogenic activity,
determining the upregulation of CAV-1 and TSP-1 and the suppression of cyclin-D1
Automatic assessment of acoustic parameters of the singing voice: application to professional western operatic and jazz singers
Retinoids and cancer: antitumoral effects of ATRA, 9-cis RA and the new retinoid IIF on the HL-60 leukemic cell line.
Objective: To compare the antitumoral effects of all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9-cis RA) with those of 5-OH,11-O-hydrophenanthrene (IIF), a new derivative of retinoic acid. Materials and Methods: The effect of retinoids was tested on cell line HL-60. Cell differentiation and apoptosis were evaluated by morphological and biochemical analysis as bcl-2 protein and by DNA fragmentation assay. The ability to activate retinoic acid receptors (RAR) and/or retinoid X receptors (RXR) and to modulate gene expression was determined by transactivation assay. Results: With cell line HL-60, the antiproliferative effect of IIF was stronger than that of ATRA and 9-cis RA. Following retinoid treatment, cells appeared to differentiate and apoptotic cells were observed. The appearance of DNA laddering and a decrease in the amount of bcl-2 protein confirmed apoptosis. IIF transcriptionally activated RXR-γ more than RAR-α. Conclusion: The findings indicate that IIF transcriptionally activates RXR-γ preferentially, induces apoptosis and has a more antiproliferative activity than ATRA and 9-cis RA on cell line HL-60
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