To understand the evolution of lung uptake of 111-In-Pentetreotide in a rat model of pulmonary radiation pneumonitis.
A 15 Gy 60-Co thoracic irradiation (1.4 Gy/min) was delivered to Wistar rats. ...Irradiated and control animals were studied during 8 weeks after irradiation. 24 hours after an injection of 111-In-pentetreotide (12-18 MBq), the uptake in the lung tissue (ULT), in the alveolar cells (UpC) and in different organs, was determined. Histological examinations were performed.
ULT and UpC after irradiation increased significantly peaking at 4 weeks (ULT: 32.8 +/- 13.0 in 10(-5) of the injected dose versus 10.8 +/- 2.0 for control; and, UpC was 19.3 +/- 7.2 versus 7.3 +/- 4.1) and decreased afterwards. Pre-injection of cold octreotide decreased the lung uptake. This evolution parallels the histological changes: alveolitis with granulomas in the interstitium at 4 weeks followed by development of sites of interstitial fibrosis. These observations suggest that the uptake is due to activated cells, mainly macrophages within the granulomas and in the alveoli, expressing somatostatin receptors.
1) The uptake of 111-In-pentetreotide in injured lungs after irradiation, already described in man, was confirmed in a rat model; 2) our results suggest that it is possible to follow the evolution of radiation lung injury by using In-111-pentetreotide.
We present a comprehensive statistical analysis of star-forming objects located in the vicinities of 1 360 bubble structures throughout the Galactic Plane and their local environments. The ...compilation of ~70 000 star-forming sources, found in the proximity of the ionized (Hii) regions and detected in both Hi-GAL and GLIMPSE surveys, provided a broad overview of the different evolutionary stages of star-formation in bubbles, from prestellar objects to more evolved young stellar objects (YSOs). Surface density maps of star-forming objects clearly reveal an evolutionary trend where more evolved star-forming objects are found spatially located near the center, while younger star-forming objects are found at the edge of the bubbles. We derived dynamic ages for a subsample of 182 Hii regions for which kinematic distances and radio continuum flux measurements were available. We detect ~80% more star-forming sources per unit area in the direction of bubbles than in the surrounding fields. We estimate ~10% clump formation efficiency (CFE) of Hi-GAL clumps in bubbles, twice the CFE in fields not affected by feedback. We find higher CFE of protostellar clumps in younger bubbles, whose density of the bubble shells is higher. We argue that the formation rate from prestellar to protostellar phase is probably higher during the early stages of the bubble expansion. Evaluation of the fragmentation time inside the shell of bubbles advocates the preexistence of clumps in the medium before the bubble, as supported by numerical simulations. Approximately 23% of the Hi-GAL clumps are found located in the direction of a bubble, with 15% for prestellar clumps and 41% for protostellar clumps. We argue that the high fraction of protostellar clumps may be due to the acceleration of the star-formation process cause by the feedback of the (Hii) bubbles.
We present a numerical model applied to the simulation of granular flow in a fluid. The description of particle flow is discrete. Particle trajectories are calculated by Newton's law and collisions ...are described by a soft-sphere approach. The fluid flow is modelled using the Navier-Stokes equation. The momentum transfer is directly calculated from the stress tensor around particles. This model is validated through the calculation of the drag coefficient, making it possible to discern the limitations on the Reynolds number according to the mesh size and the computational time. The accuracy of the Navier-Stokes solver is estimated by the calculation of the hydrodynamic drag of a fluid flowing through a porous media at low Reynolds numbers. The analysis shows that dense media require a smaller mesh size than diluted media. This model is then used to describe the sedimentation of two particles to reproduce the "Draft, Kiss and Tumbled" effect. This shows the capacity of the model to reproduce hydrodynamic interactions acting on the scale of the particle. The terminal velocity of particles is in good agreement with experiments. Simulations of the sedimentation of a system of particles makes it possible to recover the Richardson and Zaki law in an acceptable CPU time. PUBLICATION ABSTRACT
Hi-GAL is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 \(\mu\)m. We present a band-merged catalogue of spatially matched ...sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogs presented in Molinari et al. (2016a), covering the portion of Galactic plane \(-71.0^{\circ}< \ell < 67.0^{\circ}\). The band-merged catalogue contains 100922 sources with a regular SED, 24584 of which show a 70 \(\mu\)m counterpart and are thus considered proto-stellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterise different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in proto-stellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to proto-stellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between "on-arm" and "inter-arm" positions.
Diverses expressions permettent de calculer la perte de charge occasionnée par le passage d'un fluide visqueux incompressible en écoulement à travers un milieu granulaire. Ces lois ont toutes une ...origine phénoménologique et sont obtenues à partir d'expériences réalisées à une échelle macroscopique. L'une d'entre elles, la loi d'Ergun, est couramment utilisée sous une forme locale dans des modèles de couplage fluide-solide pour réaliser le transfert de quantité de mouvement entre les deux phases sans réelle justification. Dans cet article, la simulation numérique directe des équations de Navier-Stokes est utilisée pour calculer les pertes de charge de fluide visqueux incompressible en écoulement à travers un milieu granulaire. Des simulations effectuées pour différents volumes de matériau granulaire permettent de retrouver la loi de perte de charge d'Ergun, de définir un volume élémentaire représentatif et de prouver le caractère local de cette loi. Several expressions can be used to predict the pressure drop caused by a viscous incompressible fluid flow through a granular media. These laws are empiricals and are obtained at macroscopic scale. One of these, Ergun's law, is currently used in a local form to modelling the momentum transfer between fluid and solid. There is not a real justification. In these study, the direct simulation of Navier-Stokes Equation is used to calculate pressure drop caused by viscous incompressible fluid flow through a granular media. Some simulations realised for different volume of granular media allow to find a representative elementary volume and prove the local character of the Ergun's law.
Aims.This paper describes the design goals and engineering efforts that led to the realization of AMBER (Astronomical Multi BEam combineR) and to the achievement of its present performance. ...Methods.On the basis of the general instrumental concept, AMBER was decomposed into modules whose functions and detailed characteristics are given. Emphasis is put on the spatial filtering system, a key element of the instrument. We established a budget for transmission and contrast degradation through the different modules, and made the detailed optical design. The latter confirmed the overall performance of the instrument and defined the exact implementation of the AMBER optics. Results.The performance was assessed with laboratory measurements and commissionings at the VLTI, in terms of spectral coverage and resolution, instrumental contrast higher than 0.80, minimum magnitude of 11 in K, absolute visibility accuracy of 1%, and differential phase stability of 10-3 rad over one minute.
The Créteil method is a logical and simple system for intracavitary therapy of cervical and uterine cancer. The system is based on the use of a plastic cervico-vaginal moulage loaded with 0.5 mm ...diameter iridium 192 wire sources. The dimensions of both the moulage and the sources correspond to the size of the cervix being treated according to precisely defined relationships. The dose is specified on a reference isodose of a "fixed" value enclosing the pear-shaped target volume whose dimensions depend on the geometry of the sources. Source geometry in turn, depends on the size of the cervix. Thus, the dimensions of the target volume can be accurately predicted at the time of the application. Furthermore, treatment can be performed in a single application, with all sources having the same linear reference air kerma rate (or activity). Radioprotective measures are simple but effective and the patient is not subjected to the restrictions imposed by attachment to an after-loading apparatus. Our clinical results for early Stage T1 and T2a cervical tumors show excellent local control without major treatment complications or long term sequelae.
PDF
