Consistency checks of results from a Monte Carlo code intercomparison for emitted electron spectra and energy deposition around a single gold nanoparticle irradiated by X-rays

Organized by the European Radiation Dosimetry Group (EURADOS), a Monte Carlo code intercomparison exercise was conducted where participants simulated the emitted electron spectra and energy deposition around a single gold nanoparticle (GNP) irradiated by X-rays. In the exercise, the participants scored energy imparted in concentric spherical shells around a spherical volume filled with gold or water as well as the spectral distribution of electrons leaving the GNP. Initially, only the ratio of energy deposition with and without GNP was to be reported. During the evaluation of the exercise, however, the data for energy deposition in the presence and absence of the GNP were also requested. A GNP size of 50 nm and 100 nm diameter was considered as well as two different X-ray spectra (50 kVp and 100 kVp). This introduced a redundancy that can be used to cross-validate the internal consistency of the simulation results. In this work, evaluation of the reported results is presented in terms of integral quantities that can be benchmarked against values obtained from physical properties of the radiation spectra and materials involved. The impact of different interaction cross-section datasets and their implementation in the different Monte Carlo codes is also discussed

Individual and environmental determinants associated with longer times to access pediatric rheumatology centers for patients with juvenile idiopathic arthritis, a JIR cohort study.

Despite guidelines, poor access to appropriate care for juvenile idiopathic arthritis (JIA) patients remains a global issue. Prompt referral to a pediatric rheumatology (PR) center and effective care is known to be critical for changing the natural history of the disease and improving long-term prognosis. This project assesses socio-economic factors of delayed referral to a pediatric rheumatologist (PRst) for JIA patients in France and Switzerland within the Juvenile Inflammatory Rheumatism (JIR) Cohort. All patients diagnosed with JIA, presenting at one center of the JIRcohort in France or Switzerland with additional data on referral pathway were included. Patient characteristics at first visit to the PR center, dates of visits to healthcare providers during referral, and parent characteristics were extracted from the JIRcohort database. Two hundred fifty children were included. The overall median time to first PR assessment was 2.4 months [1.3; 6.9] and ranged widely across the JIA subtypes, from 1.4 months [0.6; 3.8] for children with systemic juvenile idiopathic arthritis (sJIA) to 5.3 months [2.0; 19.1] for children with enthesitis-related arthritis (ERA). A diagnosis of ERA and an appointment with an orthopedist during the referral pathway were significantly associated with a longer time before the first PR visit (hazard ratio HR 0.50 [95% CI: 0.29; 0.84]) and HR 0.68 [95% CI: 0.49; 0.93], respectively) in multivariable analysis. Having a mother with a post-graduate educational attainment level was tendentially associated with a shorter time before the first PR visit, (HR 1.32 [95% CI: 0.99; 1.78]). Time to first PRst visit was most often short compared to other studies and close to the British recommendations. However, this time remained too long for many patients. We observed no social inequities in access to a PRst, but we show the need to improve effective pathway and access to a PR center for JIA patients

The genetic diversity, phylogeography and morphology of Elphidiidae (Foraminifera) in the Northeast Atlantic

Genetic characterisation (SSU rRNA genotyping) and Scanning ElectronMicroscope (SEM) imaging of individualtests were used in tandem to determine the modern species richness of the foraminiferal family Elphidiidae(Elphidium, Haynesina and related genera) across the Northeast Atlantic shelf biomes. Specimens were collectedat 25 locations fromthe High Arctic to Iberia, and a total of 1013 individual specimenswere successfully SEMimagedand genotyped. Phylogenetic analyses were carried out in combination with 28 other elphidiid sequencesfrom GenBank and seventeen distinct elphidiid genetic types were identified within the sample set, sevenbeing sequenced for the first time. Genetic types cluster into sevenmain cladeswhich largely represent their generalmorphologicalcharacter. Differences between genetic types at the genetic, morphological and biogeographiclevels are indicative of species level distinction. Their biogeographic distributions, in combination with elphidiidSSU sequences from GenBank and high resolution images from the literature show that each of them exhibitsspecies-specific rather than clade-specific biogeographies. Due to taxonomic uncertainty and divergent taxonomicconcepts between schools, we believe that morphospecies names should not be placed onto molecularphylogenies unless both the morphology and genetic type have been linked to the formally named holotype,or equivalent. Based on strictmorphological criteria,we advocate using only a three-stage approach to taxonomyfor practical application in micropalaeontological studies. It comprises genotyping, the production of a formalmorphological description of the SEM images associated with the genetic type and then the allocation of themost appropriate taxonomic name by comparison with the formal type description. Using this approach, wewere able to apply taxonomic names to fifteen genetic types. One of the remaining two may be potentially cryptic,and one is undescribed in the literature. In general, the phylogeographic distribution is in agreement with ourknowledge of the ecology and biogeographical distribution of the corresponding morphospecies, highlighting thegenerally robust taxonomic framework of the Elphidiidae in time and space

A TEM study of grain boundaries in internal boundary layer capacitors based on donor-doped (Sr, Ca) TiO3 ceramics

International audienceDonor-doped (Sr, Ca)TiO3 ceramics, either oxidized or infiltrated by Bi2O3 and Bi2O3-PbO molten mixtures, have been studied using a transmission electron microscope equipped with EDX facilities. Grain boundary morphologies of these different materials are investigated. In oxidized samples, grain surfaces exhibit a chemical contrast, interpreted as the result of a TiO2 segregation that occurs during the sintering stage. Moreover, the in-detail characterization of infiltrated specimens reveals that intergranular regions present a facies strongly influenced by the type of mixture used. During the infiltration step, grains are slightly dissolved by molten oxides and Pb noticeably enhances this process

GEANT4 simulation of cyclotron radioisotope production in a solid target

Abstract not availableF. Poignant, S. Penfold, J. Asp, P. Takhar, P. Jackso

Theoretical study of W-values for particle impact on water

The W-values and the differential values w, were calculated by electron, proton and antiproton impact on liquid and vapor water. Two different theoretical approximations were used: the Fowler Equation (based on the Continuous Slowing Down Approximation), and the Monte Carlo code MDM, which does an event-by-event tracking of all generated particles in the media. The dependence on the type and charge of the projectiles and the relevance on the appropriate inelastic cross sections employed in the calculations were studied. For electron impact, results obtained with both models are in good agreement with experimental data and with other theoretical calculations. However, the MDM results are more representative of the stochastic nature of radiation-media interactions. The w-values for swift proton and antiproton impact on vapor water, calculated using the Fowler Equation, are in very good agreement with the results obtained by electron impact in the same velocity regime.Fil: Tessaro, Veronica Belen. Universite Claude Bernard Lyon 1. Institut de Physique Nucléaire de Lyon.; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Poignant, F.. Universite Claude Bernard Lyon 1. Institut de Physique Nucléaire de Lyon.; FranciaFil: Gervais, B.. Universite de Caen Basse Normandie; FranciaFil: Beuve, M.. Universite Claude Bernard Lyon 1. Institut de Physique Nucléaire de Lyon.; FranciaFil: Galassi, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentin