508 research outputs found
Planetary Science Virtual Observatory architecture
In the framework of the Europlanet-RI program, a prototype of Virtual
Observatory dedicated to Planetary Science was defined. Most of the activity
was dedicated to the elaboration of standards to retrieve and visualize data in
this field, and to provide light procedures to teams who wish to contribute
with on-line data services. The architecture of this VO system and selected
solutions are presented here, together with existing demonstrators
Improving the molecular diagnosis of Chlamydia psittaci and Chlamydia abortus infection with a species-specific duplex real-time PCR.
Chlamydia psittaci and Chlamydia abortus are closely related intracellular bacteria exhibiting different tissue tropism that may cause severe but distinct infection in humans. C. psittaci causes psittacosis, a respiratory zoonotic infection transmitted by birds. C. abortus is an abortigenic agent in small ruminants, which can also colonize the human placenta and lead to foetal death and miscarriage. Infections caused by C. psittaci and C. abortus are underestimated mainly due to diagnosis difficulties resulting from their strict intracellular growth. We developed a duplex real-time PCR to detect and distinguish these two bacteria in clinical samples. The first PCR (PCR1) targeted a sequence of the 16S-23S rRNA operon allowing the detection of both C. psittaci and C. abortus. The second PCR (PCR2) targeted the coding DNA sequence CPSIT_0607 unique to C. psittaci. The two PCRs showed 100 % detection for â„ 10 DNA copies per reaction (1000 copies ml- 1). Using a set of 120 samples, including bacterial reference strains, clinical specimens and infected cell culture material, we monitored 100 % sensitivity and 100 % specificity for the detection of C. psittaci and C. abortus for PCR1. When PCR1 was positive, PCR2 could discriminate C. psittaci from C. abortus with a positive predictive value of 100 % and a negative predictive value of 88 %. In conclusion, this new duplex PCR represents a low-cost and time-saving method with high-throughput potential, expected to improve the routine diagnosis of psittacosis and pregnancy complication in large-scale screening programs and also during outbreaks
On discretization in time in simulations of particulate flows
We propose a time discretization scheme for a class of ordinary differential
equations arising in simulations of fluid/particle flows. The scheme is
intended to work robustly in the lubrication regime when the distance between
two particles immersed in the fluid or between a particle and the wall tends to
zero. The idea consists in introducing a small threshold for the particle-wall
distance below which the real trajectory of the particle is replaced by an
approximated one where the distance is kept equal to the threshold value. The
error of this approximation is estimated both theoretically and by numerical
experiments. Our time marching scheme can be easily incorporated into a full
simulation method where the velocity of the fluid is obtained by a numerical
solution to Stokes or Navier-Stokes equations. We also provide a derivation of
the asymptotic expansion for the lubrication force (used in our numerical
experiments) acting on a disk immersed in a Newtonian fluid and approaching the
wall. The method of this derivation is new and can be easily adapted to other
cases
Association between High Levels of Blood Macrophage Migration Inhibitory Factor, Inappropriate Adrenal Response, and Early Death in Patients with Severe Sepsis
Background.Identification of new therapeutic targets remains an imperative goal to improve the morbidity and mortality associated with severe sepsis and septic shock. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine and counterregulator of glucocorticoids, has recently emerged as a critical mediator of innate immunity and experimental sepsis, and it is an attractive new target for the treatment of sepsis. Methods.Circulating concentrations of MIF were measured in 2 clinical trial cohorts of 145 pediatric and adult patients who had severe sepsis or septic shock caused predominantly by infection with Neisseria meningitidis or other gram-negative bacteria, to study the kinetics of MIF during sepsis, to analyze the interplay between MIF and other mediators of sepsis or stress hormones (adrenocorticotropic hormone and cortisol), and to determine whether MIF is associated with patient outcome. Results.Circulating concentrations of MIF were markedly elevated in 96% of children and adults who had severe sepsis or septic shock, and they remained elevated for several days. MIF levels were correlated with sepsis severity scores, presence of shock, disseminated intravascular coagulation, urine output, blood pH, and lactate and cytokine levels. High levels of MIF were associated with a rapidly fatal outcome. Moreover, in meningococcal sepsis, concentrations of MIF were positively correlated with adrenocorticotropic hormone levels and negatively correlated with cortisol levels and the cortisol : adrenocorticotropic hormone ratio, suggesting an inappropriate adrenal response to sepsis. Conclusions.MIF is markedly and persistently up-regulated in children and adults with gram-negative sepsis and is associated with parameters of disease severity, with dysregulated pituitary-adrenal function in meningococcal sepsis, and with early deat
Thermal maps and properties of comet 67P as derived from Rosetta/VIRTIS data
After a 10-year cruise, the Rosetta
spacecraft began a close exploration of its main target,
comet 67P/Churyumov-Gerasimenko, in July 2014.
Since then, the Visible InfraRed Thermal Imaging
Spectrometer (VIRTIS) acquired hyperspectral
images of the cometâs surface with an unprecedented
spatial resolution. VIRTIS data are routinely used to
map the surface composition and to retrieve surface
temperatures on the dayside of the comet.
The thermal behavior of the surface of comet 67P
is related to composition and physical properties that
provide information about the nature and evolution of
those materials.
Here we present temperature maps of comet 67P
that were observed by Rosetta under different illumination conditions and different local solar times
Does natural selection explain the fine scale genetic structure at the nuclear exon Glu-5 0 in blue mussels from Kerguelen?
Abstract The Kerguelen archipelago, isolated in the Southern Ocean, shelters a blue mussel Mytilus metapopulation far from any influence of continental populations or any known hybrid zone. The finely carved coast leads to a highly heterogeneous habitat. We investigated the impact of the environment on the genetic structure in those Kerguelen blue mussels by relating allele frequencies to habitat descriptors. A total sample comprising up to 2248 individuals from 35 locations was characterized using two nuclear markers, mac-1 and Glu-5 0 , and a mitochondrial marker (COI). The frequency data from 9 allozyme loci in 9 of these locations were also reanalyzed. Two other nuclear markers (EFbis and EFprem's) were monomorphic. Compared to Northern Hemisphere populations, polymorphism in Kerguelen blue mussels was lower for all markers except for the exon Glu-5 0 . At Glu-5 0 , genetic differences were observed between samples from distinct regions (F CT = 0.077), as well as within two regions, including between samples separated by <500 m. No significant differentiation was observed in the AMOVA analyses at the two other markers (mac-1 and COI). Like mac-1, all allozyme loci genotyped in a previous publication, displayed lower differentiation (Jost's D) and F ST values than Glu-5 0 . Power simulations and confidence intervals support that Glu-5 0 displays significantly higher differentiation than the other loci (except a single allozyme for which confidence intervals overlap). AMOVA analyses revealed significant effects of the giant kelp Macrocystis and wave exposure on this marker. We discuss the influence of hydrological conditions on the genetic differentiation among regions. In marine organisms with high fecundity and high dispersal potential, gene flow tends to erase differentiation, but this study showed significant differentiation at very small distance. This may be explained by the particular hydrology and the carved coastline of the Kerguelen archipelago, together with spatially variable selection at Glu-5 0
Yersinia ruckeri, an unusual microorganism isolated from a human wound infection
Abstract We report the first documented case of Yersinia ruckeri isolated from a wound infection, in a 16-year-old male after hitting a stone while paddling in a river
Advancing Our Understanding of Martian Proton Aurora through a Coordinated Multi-Model Comparison Campaign
Proton aurora are the most commonly observed yet least studied type of aurora at Mars. In order to better understand the physics and driving processes of Martian proton aurora, we undertake a multi-model comparison campaign. We compare results from four different proton/hydrogen precipitation models with unique abilities to represent Martian proton aurora: Jolitz model (3-D Monte Carlo), Kallio model (3-D Monte Carlo), Bisikalo/Shematovich et al. model (1-D kinetic Monte Carlo), and Gronoff et al. model (1-D kinetic). This campaign is divided into two steps: an inter-model comparison and a data-model comparison. The inter-model comparison entails modeling five different representative cases using similar constraints in order to better understand the capabilities and limitations of each of the models. Through this step we find that the two primary variables affecting proton aurora are the incident solar wind particle flux and velocity. In the data-model comparison, we assess the robustness of each model based on its ability to reproduce a MAVEN/IUVS proton aurora observation. All models are able to effectively simulate the data. Variations in modeled intensity and peak altitude can be attributed to differences in model capabilities/solving techniques and input assumptions (e.g., cross sections, 3-D versus 1-D solvers, and implementation of the relevant physics and processes). The good match between the observations and multiple models gives a measure of confidence that the appropriate physical processes and their associated parameters have been correctly identified and provides insight into the key physics that should be incorporated in future models
Airway structural cells regulate TLR5-mediated mucosal adjuvant activity
Antigen-presenting cell (APC) activation is enhanced by vaccine adjuvants. Most vaccines are based on the assumption that adjuvant activity of Toll-like receptor (TLR) agonists depends on direct, functional activation of APCs. Here, we sought to establish whether TLR stimulation in non-hematopoietic cells contributes to flagellinâs mucosal adjuvant activity. Nasal administration of flagellin enhanced T-cell-mediated immunity, and systemic and secretory antibody responses to coadministered antigens in a TLR5-dependent manner. Mucosal adjuvant activity was not affected by either abrogation of TLR5 signaling in hematopoietic cells or the presence of flagellin-specific, circulating neutralizing antibodies. We found that flagellin is rapidly degraded in conducting airways, does not translocate into lung parenchyma and stimulates an early immune response, suggesting that TLR5 signaling is regionalized. The flagellin-specific early response of lung was regulated by radioresistant cells expressing TLR5 (particularly the airway epithelial cells). Flagellin stimulated the epithelial production of a small set of mediators that included the chemokine CCL20, which is known to promote APC recruitment in mucosal tissues. Our data suggest that (i) the adjuvant activity of TLR agonists in mucosal vaccination may require TLR stimulation of structural cells and (ii) harnessing the effect of adjuvants on epithelial cells can improve mucosal vaccines.Fil: Van Maele, Laurye. Institut Pasteur de Lille. Lille; Francia. Univ Lille Nord de France. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; FranciaFil: Fougeron, Delphine. Institut Pasteur de Lille. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Univ Lille Nord de France. Lille; FranciaFil: Janot, Laurent. University of OrlĂ©ans. OrlĂ©ans; Francia. Institut de Transgenose. Orleans; FranciaFil: Didierlaurent, A.. Imperial College of London. Londres; Reino UnidoFil: Cayet, D.. Institut Pasteur de Lille. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Univ Lille Nord de France. Lille; FranciaFil: Tabareau, J.. Institut Pasteur de Lille. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Univ Lille Nord de France. Lille; FranciaFil: Rumbo, MartĂn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Estudios InmunolĂłgicos y FisiopatolĂłgicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios InmunolĂłgicos y FisiopatolĂłgicos; ArgentinaFil: Corvo Chamaillard, S.. Institut Pasteur de Lille. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Univ Lille Nord de France. Lille; FranciaFil: Boulenoir, S.. Institut Pasteur de Lille. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Univ Lille Nord de France. Lille; FranciaFil: Jeffs, S. Imperial College of London. Londres; Reino UnidoFil: Vande Walle, L. Department of Medical Protein Research. Ghent; BĂ©lgica. University of Ghent; BĂ©lgicaFil: Lamkanfi, M.. Department of Medical Protein Research. Ghent; BĂ©lgica. University of Ghent; BĂ©lgicaFil: Lemoine, Y.. Univ Lille Nord de France. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Institut Pasteur de Lille. Lille; FranciaFil: Erard, F.. Institut de Transgenose. Orleans; Francia. University of OrlĂ©ans. OrlĂ©ans; FranciaFil: Hot, D.. Univ Lille Nord de France. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Institut Pasteur de Lille. Lille; FranciaFil: Hussell, Tracy. Imperial College of London. Londres; Reino Unido. University of Manchester; Reino UnidoFil: Ryffel, B.. Institut de Transgenose. Orleans; Francia. University of OrlĂ©ans. OrlĂ©ans; FranciaFil: Benecke, Arndt G.. Institut des Hautes Ătudes Scientifiques and Centre National de la Recherche Scientifique; FranciaFil: Sirard, J.C.. Univ Lille Nord de France. Lille; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Institut Pasteur de Lille. Lille; Franci
CN and OH emissions in the 67P/Churyumov-Gerasimenko coma with Rosetta/VIRTIS-M spectrometer
Observations with the visible channel of the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) on board Rosetta taken when the spacecraft was at a distance of 80-140 km from 67P/Churyumov-Gerasimenko (67P/C-G) allowed the detection of daughter gaseous species in its inner coma. The detection of the violet doublet emission of CN at 388.3 nm has occurred during the coma monitoring campaign in November-December 2015, when the instrument has operated with long integration times (50 s) necessary to boost the instrumental SNR and detect these faint emissions. Other features, like the C3 and C2 signatures around 420-480 nm, might possibly be visible in few cases but with a very low intensity. For this reason, we concentrate our analysis in the spectral region from 250 to 450 nm, where the detector sensitivity allows the positive detection of the above mentioned CN violet line at 388.3 nm, and the OH doublet emission at 309 nm. The CN emission at 388.3 nm is observed on both the day and night sides of 67P/C-G with a higher intensity on the dayside. In addition, at a preliminary analysis, the hydroxyl doublet emission intensity seems to be comparable to the violet CN line. The same emissions were also identified in spectra acquired using ground-based facilities, when the comet had just passed the perihelion (Fitzsimmons et al., 2016). These gaseous species emissions appear well contrasted with respect to the dust broad continuum, preferentially observed on the dayside. Distribution and variability of the OH and CN band intensities will be discussed with respect to observation parameters
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