Search

Resume Introduction La drepanocytose est la premiere maladie genetique en Ile-de-France. L’accident vasculaire cerebral est l’une des complications la plus severe de cette maladie. Chez l’enfant drepanocytaire SS, le Doppler transcrânien (DTC) est, par le biais de l’etude des vitesses moyennes des arteres de la base du crâne, le « gold standard » pour le depistage et le diagnostic de vasculopathie. A notre connaissance, chez l’adulte drepanocytaire, aucune norme concernant les vitesses des arteres de la base du crâne, n’a ete etablie. Il nous est donc apparu utile d’etablir une approche des vitesses cerebrales enregistrees chez les adultes drepanocytaires SS sans complication neurovasculaire. Materiel et methodes Il s’agit d’une etude observationnelle, prospective, monocentrique realisee entre fevrier 2017 et juin 2017. L’objectif principal de l’etude etant de determiner la moyenne et l’ecart-type des vitesses systoliques maximales (VSM) et les moyennes des vitesses maximales pour l’ensemble des arteres enregistrees lors de l’echo Doppler transcrânien. Les objectifs secondaires etant, d’une part, de comparer les moyennes des vitesses systoliques maximales chez l’adulte drepanocytaire a celles de l’adulte sain, ainsi qu'a celles des enfants drepanocytaires, , d’autre part, de determiner si des parametres pouvaient influencer sur les vitesses enregistrees au DTC. Resultats Quarante patients ont ete inclus entre le 1er fevrier 2017 et le 30 juin 2017, avec un âge moyen de 39,3 ans. La moyenne des vitesses maximales au niveau des arteres est de : 78 cm/s pour les arteres cerebrales moyennes ; 59,6 cm/s pour les arteres carotides internes ; 61 cm/s pour les arteres cerebrales anterieures ; 44 cm/s pour les arteres cerebrales posterieures et de 55 cm/s pour le tronc basilaire. Discussion Les vitesses circulatoires les plus elevees sont retrouvees au niveau des arteres cerebrales moyennes. Les vitesses retrouvees au niveau des arteres carotides internes et des arteres cerebrales anterieures sont superieures aux vitesses du systeme vertebrobasilaire. Les vitesses chez l’adulte drepanocytaire sont plus basses que celles decrites chez l’enfant drepanocytaire SS, mais sont significativement plus elevees par rapport aux vitesses retrouvees chez l’adulte sain. Conclusion Cette etude est a notre connaissance la premiere evaluant les vitesses circulatoires au Doppler transcrânien chez l’adulte drepanocytaire. Ce travail presente des limites du fait de son faible echantillon, cependant, elle constitue une base pour les etudes ulterieures concernant le Doppler transcrânien chez l’adulte drepanocytaire.

Sickle cell disease is the leading genetic disease in Île-de-France. Stroke is one of its most severe complications. In SS sickle cell children, transcranial Doppler (TDC) is, through the study of average speeds of the skull base arteries, the gold standard for screening and diagnosis of vasculopathy. To our knowledge, in adults with sickle cell disease, no standards have been established for the speed of the arteries at the base of the skull. It therefore seemed useful to us to establish an approach to brain speeds recorded in adults with sickle cell disorders without neurovascular complications.This was an observational, prospective, monocentric study conducted between February 2017 and June 2017. The main objective of the study was to determine the mean and standard deviation of maximum systolic velocities (MSS) and mean maximum velocities for all arteries recorded during the transcranial Doppler echo. The secondary objectives were to compare the mean maximum systolic velocities in sickle cell adults with those of healthy adults, to compare the mean maximum systolic velocities in sickle cell adults with those of sickle cell children, and to determine whether parameters could influence the speeds recorded at TCD.Forty patients were included between February 1, 2017 and June 30, 2017, with an average age of 39.3 years. The mean maximum velocities recorded were: 78cm/s for the middle cerebral arteries; 59.6cm/s for the internal carotid arteries; 61cm/s for the anterior cerebral arteries; 44cm/s for the posterior cerebral arteries and 55cm/s for the basilar trunk.The highest circulatory velocities are found in the middle cerebral arteries. The speeds found in the internal carotid arteries and anterior cerebral arteries are faster than in the vertebrobasilar system. Speeds in sickle cell adults are slower than those described in sickle cell children SS but significantly faster than those found in healthy adults.To our knowledge, this study is the first to evaluate transcranial Doppler circulatory velocities in adult sickle cell patients. This work has limitations due to its small sample size, however, it provides a basis for further studies on transcranial Doppler in sickle cell adults.

We present results of the detailed dust energy balance study for the seven large edge-on galaxies in the HEROES sample using 3D radiative transfer (RT) modelling. Based on available optical and near-infrared observations of the HEROES galaxies, we derive the 3D distribution of stars and dust in these galaxies. For the sake of uniformity, we apply the same technique to retrieve galaxy properties for the entire sample: we use a stellar model consisting of a S\'ersic bulge and three double-exponential discs (a superthin disc for a young stellar population and thin and thick discs for old populations). For the dust component, we adopt a double-exponential disc with the new THEMIS dust-grain model. We fit oligochromatic radiative transfer (RT) models to the optical and near-infrared images with the fitting algorithm FitSKIRT and do panchromatic simulations with the SKIRT code at wavelengths ranging from ultraviolet to submillimeter. We confirm the previously stated dust energy balance problem in galaxies: for the HEROES galaxies, the dust emission derived from our RT calculations underestimates the real observations by a factor 1.5-4 for all galaxies except NGC 973 and NGC 5907 (apparently, the latter galaxy has a more complex geometry than we used). The comparison between our RT simulations and the observations at mid-infrared-submillimeter wavelengths shows that most of our galaxies exhibit complex dust morphologies (possible spiral arms, star-forming regions, more extended dust structure in the radial and vertical directions). We suggest that, in agreement with the results from Saftly et al. (2015), the large- and small-scale structure is the most probable explanation for the dust energy balance problem., Comment: 53 pages, 31 figures, Accepted for publication in Astronomy & Astrophysics

Locked coil strands can be used in all types of rope supported bridges where long-term corrosion protection is a primary requirement. This paper reports advances of corrosion protection of locked coil strands with galvanically protective coatings and high density polyethylene (HDPE) sheathing.

Recent cosmological hydrodynamical simulations suggest that baryonic processes, and in particular supernova feedback after bursts of star formation, can alter the structure of dark matter haloes and transform primordial cusps into shallower cores. To assess whether this mechanism offers a solution to the cusp-core controversy, simulated haloes must be compared to real dark matter haloes inferred from galaxy rotation curves. For this purpose, two new dark matter density profiles were recently derived from simulations of galaxies in complementary mass ranges: the DC14 halo ($10^{10} < M_{\text{halo}}/M_{\odot} < 8 \times 10^{11}$) and the coreNFW halo ($10^{7} < M_{\text{halo}}/M_{\odot} < 10^{9}$). Both models have individually been found to give good fits to observed rotation curves. For the DC14 model, however, the agreement of the predicted halo properties with cosmological scaling relations was confirmed by one study, but strongly refuted by another. A next question is whether the two models converge to the same solution in the mass range where both should be appropriate. To investigate this, we tested the DC14 and cNFW halo models on the rotation curves of a selection of galaxies with halo masses in the range $4 \times 10^{9}$ - $7 \times 10^{10}$ $M_{\odot}$. We further applied the DC14 model to a set of rotation curves at higher halo masses, up to $9 \times 10^{11}$ $M_{\odot}$, to verify the agreement with the cosmological scaling relations. We find that both models are generally able to reproduce the observed rotation curves, in line with earlier results, and the predicted dark matter haloes are consistent with the cosmological $c-M_{\text{halo}}$ and $M_{*}-M_{\text{halo}}$ relations. The DC14 and cNFW models are also in fairly good agreement with each other, even though DC14 tends to predict slightly less extended cores and somewhat more concentrated haloes than cNFW., Comment: 19 pages, 12 figures, accepted for publication in A&A

Context. Edge-on galaxies can offer important insights in galaxy evolution as they are the only systems where the distribution of the different components can be studied both radially and vertically. The HEROES project was designed to investigate the interplay between the gas, dust, stars and dark matter (DM) in a sample of 7 massive edge-on spiral galaxies. Aims. In this second HEROES paper we present an analysis of the atomic gas content of 6 out of 7 galaxies in our sample. The remaining galaxy was recently analysed according to the same strategy. The primary aim of this work is to constrain the surface density distribution, the rotation curve and the geometry of the gas disks in a homogeneous way. In addition we identify peculiar features and signs of recent interactions. Methods. We construct detailed tilted-ring models of the atomic gas disks based on new GMRT 21-cm observations of NGC 973 and UGC 4277 and re-reduced archival HI data of NGC 5907, NGC 5529, IC 2531 and NGC 4217. Potential degeneracies between different models are resolved by requiring a good agreement with the data in various representations of the data cubes. Results. From our modelling we find that all but one galaxy are warped along the major axis. In addition, we identify warps along the line of sight in three galaxies. A flaring gas layer is required to reproduce the data only for one galaxy, but (moderate) flares cannot be ruled for the other galaxies either. A coplanar ring-like structure is detected outside the main disk of NGC 4217, which we suggest could be the remnant of a recent minor merger event. We also find evidence for a radial inflow of 15 +- 5 km/s in the disk of NGC 5529, which might be related to the ongoing interaction with two nearby companions. (Abridged), 39 pages, 38 figures, Accepted for publication in Astronomy & Astrophysics

We investigate the dust energy balance for the edge-on galaxy IC 2531, one of the seven galaxies in the HEROES sample. We perform a state-of-the-art radiative transfer modelling based, for the first time, on a set of optical and near-infrared galaxy images. We show that taking into account near-infrared imaging in the modelling significantly improves the constraints on the retrieved parameters of the dust content. We confirm the result from previous studies that including a young stellar population in the modelling is important for explaining the observed stellar energy distribution. However, the discrepancy between the observed and modelled thermal emission at far-infrared wavelengths, the so-called dust energy balance problem, is still present: the model underestimates the observed fluxes by a factor of about two. We compare two different dust models, and find that dust parameters and thus the spectral energy distribution in the infrared domain are sensitive to the adopted dust model. In general, the THEMIS model reproduces the observed emission in the infrared wavelength domain better than the popular Zubko et al. BARE-GR-S model. Our study of IC 2531 is a pilot case for detailed and uniform radiative transfer modelling of the entire HEROES sample, which will shed more light on the strength and origins of the dust energy balance problem., Comment: 15 pages, 8 figures, Accepted for publication in Astronomy & Astrophysics