232 research outputs found
Analyse structurelle en angiographie cardiaque
Ce travail traite de la formation d'entités cohérentes, les segments ou les branches vasculaires, dans des images coronarographiques obtenues par rayon X. Son objectif est d'une part d'extraire l'information pertinente, préalable à une reconstruction tridimensionnelle à partir de deux projections, et d'autre part d'éliminer les objets extrinsèques présents dans les images. L'approche proposée s'appuie sur des techniques de mise en correspondance de chaînes pour former des triplets constitués de deux lignes contour et d'une ligne centrale. Nous exploitons des chaînes attribuées. La mesure de similarité entre chaînes est obtenue à partir de l'algorithme de Wagner & Fischer. Deux méthodes sont testées, la première opère une mise en correspondance en considérant des associations de chaînes par paires, la seconde propose une mise en correspondance simultanée des trois chaînes
Una aplicación de las series de lie en el estudio del problema de los dos cuerpos clásico
The classical two-body problem is analyzed by Lie series through a common regularization. It is showed that by an appropriate change of the independent variable (introducing a pseudo-time) is possible to obtain six differential equations which, integrated by Lie series, give short expressions for the components of the position and velocity vectors. In principle, the expressions are valid for the conics and the rectilinear motion.El clásico problema de dos cuerpos es analizado por series de Lie a través de una regularización común. Se muestra que por un cambio adecuado de la variable independiente (la introducción de un pseudo-tiempo) es posible obtener seis ecuaciones diferenciales que, integradas por series de Lie, dan expresiones cortas para los componentes de los vectores posición y velocidad. En principio, las expresiones son válidas para las cónicas y el movimiento rectilíneo
Nuclear Transparency to Intermediate-Energy Protons
Nuclear transparency in the (e,e'p) reaction for 135 < Tp < 800 MeV is
investigated using the distorted wave approximation. Calculations using
density-dependent effective interactions are compared with phenomenological
optical potentials. Nuclear transparency is well correlated with proton
absorption and neutron total cross sections. For Tp < 300 MeV there is
considerable sensitivity to the choice of optical model, with the empirical
effective interaction providing the best agreement with transparency data. For
Tp > 300 MeV there is much less difference between optical models, but the
calculations substantially underpredict transparency data and the discrepancy
increases with A. The differences between Glauber and optical model
calculations are related to their respective definitions of the semi-inclusive
cross section. By using a more inclusive summation over final states the
Glauber model emphasizes nucleon-nucleon inelasticity, whereas with a more
restrictive summation the optical model emphasizes nucleon-nucleus
inelasticity; experimental definitions of the semi-inclusive cross section lie
between these extremes.Comment: uuencoded gz-compressed tar file containing revtex and bbl files and
5 postscript figures, totalling 31 pages. Uses psfi
Microscopic calculations of medium effects for 200-MeV (p,p') reactions
We examine the quality of a G-matrix calculation of the effective
nucleon-nucleon (NN) interaction for the prediction of the cross section and
analyzing power for 200-MeV (p,p') reactions that populate natural parity
states in O, Si, and Ca. This calculation is based on a
one-boson-exchange model of the free NN force that reproduces NN observables
well. The G-matrix includes the effects of Pauli blocking, nuclear binding, and
strong relativistic mean-field potentials. The implications of adjustments to
the effective mass ansatz to improve the quality of the approximation at
momenta above the Fermi level will be discussed, along with the general quality
of agreement to a variety of (p,p') transitions.Comment: 36 pages, TeX, 18 figure
Recommendations for vaccination in patients with multiple sclerosis who are eligible for immunosuppressive therapies: Spanish consensus statement
Esclerosis múltiple; Vacunación; ConsensoEsclerosi múltiple; Vacunació; ConsensMultiple sclerosis; Vaccination; ConsensusAntecedentes
La reciente aparición de terapias de alta efectividad para el tratamiento de la esclerosis múltiple (EM), con potencial riesgo de complicaciones infecciosas, obliga plantear estrategias de prevención y minimización de riesgos. La vacunación constituye una parte esencial del manejo de estos pacientes. Este consenso recoge una serie de pautas y escenarios prácticos de vacunación en pacientes adultos con EM candidatos a tratamiento inmunosupresor.
Metodología
Se llevó a cabo un consenso de tipo formal. Tras definir el alcance del documento, se realizó una búsqueda bibliográfica de vacunación en pacientes con EM, así como guías de vacunación específicas de pacientes inmunosuprimidos y en tratamiento biológico con otras enfermedades. Para la formulación de las recomendaciones se empleó la metodología de Modified Nominal Group Technique.
Desarrollo
La vacunación en pacientes candidatos a tratamiento inmunosupresor se debe plantear antes de iniciar un tratamiento inmunosupresor siempre que la situación clínica del paciente lo permita. Se recomendarán tanto aquellas indicadas en el calendario vacunal del adulto, como algunas específicas, en función de la inmunidad previa. Si ya está instaurado el tratamiento inmunosupresor las vacunas vivas atenuadas estarán contraindicadas. Para aquellas vacunas que dispongan de un correlato de protección se recomienda monitorizar la respuesta serológica transcurridos de uno a 2 meses de la última dosis.Background
The recent development of highly effective treatments for multiple sclerosis (MS) and the potential risk of infectious complications require the development of prevention and risk minimisation strategies. Vaccination is an essential element of the management of these patients. This consensus statement includes a series of recommendations and practical scenarios for the vaccination of adult patients with MS who are eligible for highly effective immunosuppressive treatments.
Methodology
A formal consensus procedure was followed. Having defined the scope of the statement, we conducted a literature search on recommendations for the vaccination of patients with MS and specific vaccination guidelines for immunosuppressed patients receiving biological therapy for other conditions. The modified nominal group technique methodology was used to formulate the recommendations.
Development
Vaccination in patients who are candidates for immunosuppressive therapy should be considered before starting immunosuppressive treatment providing the patient's clinical situation allows. Vaccines included in the routine adult vaccination schedule, as well as some specific ones, are recommended depending on the pre-existing immunity status. If immunosuppressive treatment is already established, live attenuated vaccines are contraindicated. For vaccines with a correlate of protection, it is recommended to monitor the serological response in an optimal interval of 1-2 months from the last dose
Infección por protozoarios en individuos de tití bebe leche (saguinus fuscicollis), tití cabeza blanca (saguinus oedipus), tití ardilla (saimiri sciureus), suricata (suricata suricatta) y wallabie (macropus rufogriseus)
La toxoplasmosis es una de las zoonosis parasitarias más comunes y de especial atención en medicina humana y veterinaria en todo el mundo. Toxoplasma gondii comparte muchos de sus parámetros biológicos con otros parásitos apicomplexa, pero es único en su extremadamente amplio rango de huéspedes y su especificidad tisular (Smith, 1995). La susceptibilidad en especies de primates del Nuevo Mundo y macrópodos a la infección por protozoarios es alta. Bajo condiciones de cautiverio la toxoplasmosis es una de las infecciones más comunes en macrópodos australianos (Basso et al., 2007; Adkesson et al., 2007). En el presente trabajo se exponen los hallazgos clínicos y postmortem de 11 individuos de primates (Saguinus oedipus, S. fuscicollis, Saimiri sciureus), carnívoros (Suricata suricatta) y diprodontia (Macropus rufogriseus), de la Fundación Zoológica de Cali diagnosticados mediante métodos paraclínicos e histopatológicos para Toxoplasmosis. En la mayoría de los casos el cuadro clínico se caracterizó principalmente por disnea, secreción nasal espumosa y signos neurológicos. Los hallazgos más importantes de la necropsia fueron lesiones en pulmón, hígado y encéfalo. Los casos aquí descritos corresponden a cuadros clínicos de ocurrencia natural y son un acercamiento al entendimiento del desarrollo fisiopatológico y la presentación clínica de especies de fauna silvestre infectadas con protozoarios, a pesar de la falta de un diagnóstico definitivo mediante técnicas específicas de inmunohistoquímica para las distintas etiologías
Efficacy and Safety of Masitinib in Progressive Forms of Multiple Sclerosis: A Randomized, Phase 3, Clinical Trial
Background and Objectives. Masitinib is a selective tyrosine kinase inhibitor, targeting innate immune cells (mast cells and microglia) that are involved in the pathophysiology of progressive multiple sclerosis (MS).
Study AB07002 assessed oral masitinib in patients with progressive MS who were progressing but not clinically active.
Methods. This randomized, double-blind, 2 parallel-group, placebo-controlled trial assessing 2 dose levels
of masitinib vs equivalent placebo was conducted at 116 hospital clinics and specialized MS centers in 20 countries. Randomization (2:1) with minimization was performed centrally using an automated system. Patients, physicians, and outcome assessors remained masked to treatment group allocation. Patients with primary progressive MS (PPMS) or nonactive secondary progressive MS (nSPMS) without relapse for ≥2 years, aged 18–75 years, with baseline Expanded Disability Status Scale (EDSS) 2.0–6.0, and regardless of time from onset were treated for 96 weeks. The primary end point was overall EDSS change from baseline using repeated measures (generalized estimating equation, timeframe W12–W96, measured every 12 weeks), with positive values indicating increased clinical deterioration. Efficacy and safety were assessed in all randomly assigned and treated patients.
Results. A total of 611 patients were randomized; 301 in the masitinib 4.5 mg/kg/d parallel group and
310 in the uptitrated masitinib 6.0 mg/kg/d parallel group. Masitinib (4.5 mg/kg/d) (n = 199) showed significant benefit over placebo (n = 101) according to the primary end point, 0.001 vs 0.098, respectively, with a between-group difference of −0.097 (97% CI −0.192 to −0.002); p =0.0256. Safety was consistent with masitinib’s known profile (diarrhea, nausea, rash, and hematologic events), with no elevated risk of infection. Efficacy results from the independent uptitrated masitinib 6.0 mg/kg/d parallel group were inconclusive, and no new safety signal was observed.
Discussion. Masitinib (4.5 mg/kg/d) can benefit people with PPMS and nSPMS. A confirmatory phase 3
study will be initiated to substantiate these data
Sensitivity of nucleon-nucleus scattering to the off-shell behavior of on-shell equivalent NN potentials
The sensitivity of nucleon-nucleus elastic scattering to the off-shell
behavior of realistic nucleon-nucleon interactions is investigated when
on-shell equivalent nucleon-nucleon potentials are used. The study is based on
applications of the full-folding optical model potential for an explicit
treatment of the off-shell behavior of the nucleon-nucleon effective
interaction. Applications were made at beam energies between 40 and 500 MeV for
proton scattering from 40Ca and 208Pb. We use the momentum-dependent Paris
potential and its local on-shell equivalent as obtained with the
Gelfand-Levitan and Marchenko inversion formalism for the two nucleon
Schroedinger equation. Full-folding calculations for nucleon-nucleus scattering
show small fluctuations in the corresponding observables. This implies that
off-shell features of the NN interaction cannot be unambiguously identified
with these processes. Inversion potentials were also constructed directly from
NN phase-shift data (SM94) in the 0-1.3 GeV energy range. Their use in
proton-nucleus scattering above 200 MeV provide a superior description of the
observables relative to those obtained from current realistic NN potentials.
Limitations and scope of our findings are presented and discussed.Comment: 17 pages tightened REVTeX, 8 .ps figures, submitted to Phys. Rev.
Semiclassical theory of surface plasmons in spheroidal clusters
A microscopic theory of linear response based on the Vlasov equation is
extended to systems having spheroidal equilibrium shape. The solution of the
linearized Vlasov equation, which gives a semiclassical version of the random
phase approximation, is studied for electrons moving in a deformed equilibrium
mean field. The deformed field has been approximated by a cavity of spheroidal
shape, both prolate and oblate. Contrary to spherical systems, there is now a
coupling among excitations of different multipolarity induced by the
interaction among constituents. Explicit calculations are performed for the
dipole response of deformed clusters of different size. In all cases studied
here the photoabsorption strength for prolate clusters always displays a
typical double-peaked structure. For oblate clusters we find that the
high--frequency component of the plasmon doublet can get fragmented in the
medium size region (). This fragmentation is related to the
presence of two kinds of three-dimensional electron orbits in oblate cavities.
The possible scaling of our semiclassical equations with the valence electron
number and density is investigated.Comment: 23 pages, 8 figures, revised version, includes discussion of scalin
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