5,752 research outputs found
On the definition of temperature in FPU systems
It is usually assumed, in classical statistical mechanics, that the
temperature should coincide, apart from a suitable constant factor, with the
mean kinetic energy of the particles. We show that this is not the case for
\FPU systems, in conditions in which energy equipartition between the modes is
not attained. We find that the temperature should be rather identified with the
mean value of the energy of the low frequency modes.Comment: 12 pages, 4 Figure
From anomalous energy diffusion to Levy walks and heat conductivity in one-dimensional systems
The evolution of infinitesimal, localized perturbations is investigated in a
one-dimensional diatomic gas of hard-point particles (HPG) and thereby
connected to energy diffusion. As a result, a Levy walk description, which was
so far invoked to explain anomalous heat conductivity in the context of
non-interacting particles is here shown to extend to the general case of truly
many-body systems. Our approach does not only provide a firm evidence that
energy diffusion is anomalous in the HPG, but proves definitely superior to
direct methods for estimating the divergence rate of heat conductivity which
turns out to be , in perfect agreement with the dynamical
renormalization--group prediction (1/3).Comment: 4 pages, 3 figure
The clinical trial of FK 506 as primary and rescue immunosuppression in pediatric cardiac transplantation
Data accuracy on automatic traffic counting: The SMART project results
Abstract
In this paper the results of an experimental survey on traffic monitoring devices, named SMART Project, are presented. Aim of the project was to define the requirements to be applied to traffic technologies to match specific applications. The project involved the construction of a test site on a main road, where seven different traffic monitoring systems were installed. A 1 year survey was carried out to assess technologies response to environmental and mechanical solicitations. A reference system specifically devoted to check and validate the devices under test was designed for the project. Test procedures were also developed to control the results achieved. The outcomes accomplished for vehicles counting are described in details in the essay hereunder
Managing Adult-onset Still's disease: The effectiveness of high-dosage of corticosteroids as first-line treatment in inducing the clinical remission. Results from an observational study
To assess the effectiveness of the treatment with high dosage of corticosteroids (CCSs), as first-line therapy, in inducing remission in naïve Adult-onset Still's disease (AOSD) patients compared with low dosage of CCSs, after 6 months. To further evaluate the rate of patients maintaining the remission and the rate of CCSs discontinuation, after additional 12 months of follow-up.A retrospective evaluation of patients prospectively followed was designed to compare the rate of clinical remission in naïve AOSD patients treated with high dosages of CCSs (0.8-1 mg/kg/day of prednisone-equivalent) or low dosage of CCSs (0.2-0.3 mg/kg/day of prednisone-equivalent), after 6 months. An additional analysis was performed to compare the rate of monocyclic pattern between these groups, after further 12 months of follow-up.The clinical remission was achieved in a higher percentage of patients treated with the first-line treatment with high dosage of CCSs than treated the first-line treatment with low dosage of CCSs. At the end of 18 months of follow-up, a larger percentage of patients treated the first-line treatment with high dosage of CCSs was classified as monocyclic pattern and discontinued CCSs when compared with patients treated the first-line treatment with low dosage of CCSs. Patients defined as CCSs non-responder were treated with methotrexate (MTX)+CCSs or with combination therapy CCSs+MTX+biologic drug. The clinical remission was observed in a percentage of these patients.We showed the effectiveness of the first-line treatment with high dosage of CCSs in inducing clinical remission in naïve AOSD patients when compared with the first-line treatment with low dosage of CCSs. The first-line treatment with high dosage of CCSs was also associated with the achievement of monocyclic pattern and CCSs discontinuation, after 18 months of follow-up
No more time to stay ‘single’ in the detection of Anisakis pegreffii, A. simplex (s. s.) and hybridization events between them: a multi-marker nuclear genotyping approach
A multi-marker nuclear genotyping approach was performed on larval and adult specimens of Anisakis spp. (N = 689) collected from fish and cetaceans in allopatric and sympatric areas of the two species Anisakis pegreffii and Anisakis simplex
(s. s.), in order to: (1) identify specimens belonging to the parental taxa by using nuclear markers (allozymes loci) and sequence analysis of a new diagnostic nuclear DNA locus (i.e. partial sequence of the EF1 α−1 nDNA region) and (2) recognize hybrid categories. According to the Bayesian clustering algorithms, based on those markers, most of the individuals
(N = 678) were identified as the parental species [i.e. A. pegreffii or A. simplex (s. s.)], whereas a smaller portion (N = 11)
were recognized as F1 hybrids. Discordant results were obtained when using the polymerase chain reaction–restriction
fragment length polymorphisms (PCR–RFLPs) of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) on
the same specimens, which indicated the occurrence of a large number of ‘hybrids’ both in sympatry and allopatry.
These findings raise the question of possible misidentification of specimens belonging to the two parental Anisakis and
their hybrid categories derived from the application of that single marker (i.e. PCR–RFLPs analysis of the ITS of
rDNA). Finally, Bayesian clustering, using allozymes and EF1 α−1 nDNA markers, has demonstrated that hybridization
between A. pegreffii and A. simplex (s. s.) is a contemporary phenomenon in sympatric areas, while no introgressive hybridization takes place between the two species
Phase space structures and ionization dynamics of hydrogen atom in elliptically polarized microwaves
The multiphoton ionization of hydrogen atoms in a strong elliptically
polarized microwave field exhibits complex features that are not observed for
ionization in circular and linear polarized fields. Experimental data reveal
high sensitivity of ionization dynamics to the small changes of the field
polarization. The multidimensional nature of the problem makes widely used
diagnostics of dynamics, such as Poincar\'{e} surfaces of section, impractical.
We analyze the phase space dynamics using finite time stability analysis
rendered by the fast Lyapunov Indicators technique. The concept of
zero--velocity surface is used to initialize the calculations and visualize the
dynamics. Our analysis provides stability maps calculated for the initial
energy at the maximum and below the saddle of the zero-velocity surface. We
estimate qualitatively the dependence of ionization thresholds on the
parameters of the applied field, such as polarization and scaled amplitude
Blocking CD248 molecules in perivascular stromal cells of patients with systemic sclerosis strongly inhibits their differentiation toward myofibroblasts and proliferation: A new potential target for antifibrotic therapy
Background: Fibrosis may be considered the hallmark of systemic sclerosis (SSc), the end stage triggered by different pathological events. Transforming growth factor-β (TGF-β) and platelet-derived growth factor BB (PDGF-BB) are profibrotic molecules modulating myofibroblast differentiation and proliferation, respectively. There is evidence linking CD248 with these two molecules, both highly expressed in patients with SSc, and suggesting that CD248 may be a therapeutic target for several diseases. The aim of this work was to evaluate the expression of CD248 in SSc skin and its ability to modulate SSc fibrotic process. Methods: After ethical approval was obtained, skin biopsies were collected from 20 patients with SSc and 10 healthy control subjects (HC). CD248 expression was investigated in the skin, as well as in bone marrow mesenchymal stem cells (MSCs) treated with TGF-β or PDGF-BB, by immunofluorescence, qRT-PCR, and Western blotting. Finally, in SSc-MSCs, the CD248 gene was silenced by siRNA. Results: Increased expression of CD248 was found in endothelial cells and perivascular stromal cells of SSc skin. In SSc-MSCs, the levels of CD248 and α-smooth muscle actin expression were significantly higher than in HC-MSCs. In both SSc- and HC-MSCs, PDGF-BB induced increased expression of Ki-67 when compared with untreated cells but was unable to modulate CD248 levels. After CD248 silencing, both TGF-β and PDGF-BB signaling were inhibited in SSc-MSCs. Conclusions: CD248 overexpression may play an important role in the fibrotic process by modulating the molecular target, leading to perivascular cells differentiation toward myofibroblasts and interfering with its expression, and thus might open a new therapeutic strategy to inhibit myofibroblast generation during SSc
Adult-onset Still's disease: Evaluation of prognostic tools and validation of the systemic score by analysis of 100 cases from three centers
Background: Adult-onset Still's disease (AOSD) is rare inflammatory disease of unknown etiology that usually affects young adults. The more common clinical manifestations are spiking fevers, arthritis, evanescent rash, elevated liver enzymes, lymphadenopathy, hepatosplenomegaly, and serositis. The multi-visceral involvement of the disease and the different complications, such as macrophage activation syndrome, may strongly decrease the life expectancy of AOSD patients. Methods: This study aimed to identify the positive and negative features correlated with the outcome of patients. A retrospective analysis of AOSD patients prospectively admitted to three rheumatologic centers was performed to identify the clinical features present at the time of diagnosis and to predict the possible outcome. Furthermore, we investigated the as yet to be validated prognostic value of the systemic score previously proposed. Results: One hundred consecutive AOSD patients were enrolled. The mean systemic score showed that the majority of patients had a multi-organ involvement. Sixteen patients showed different complications, mainly the macrophage activation syndrome. A strong increase of inflammatory markers was observed. All patients received steroids at different dosages, 55 patients in association with immunosuppressive drugs and 32 in association with biologic agents. Sixteen patients died during the follow-up. Regression analysis showed that the higher values of the systemic score and the presence of AOSD-related complications, assessed at the time of diagnosis, were significantly correlated with patient mortality. A prognostic impact of the systemic score of 65 7.0 was reported. Conclusions: Our study showed that a higher systemic score and the presence of AOSD-related complications at the time of diagnosis were significantly associated with mortality. Of note, a cut-off at 7.0 of the systemic score showed a strong prognostic impact in identifying patients at risk of AOSD-related death
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