Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Experimentally Assisted Molecular Modelling (EAMM) is an original approach for predicting the structure of organic micro-crystals and deducing their habit in the presence of various solvents and additives. It is applied here in the case of n-octylamino-nitrobenzoxadiazole (nOA-NBD), a fluorescent compound. This general approach is first of all described and validated by its blind application to three known and closely-related crystals. Then, the whole process is applied to predict the molecular crystal generated by n-octylamino-NBD, including the molecule conformation, its structure (cell parameters, molecular packing, X-ray powder diagrams) and its theoretical plus actual habits in the presence of a solvent (p-xylene) and two additives (acetic acid and n-dodecane). The conformation of the predicted molecule is validated by comparison with two similar molecules embedded in observable crystals. Then, the choice between two proposed structures (with the same energy and two equiprobable packings) is based on the comparison between experimental and re-computed X-ray powder diffraction diagrams, and also on the interpretation of an actual TEM image in the light of the proposed cell parameters. This choice is confirmed by the comparison between the vapour-grown face development (proposed by the BFDH or the attachment energy models) and the actual face development in a pure solvent. Finally, the actual habit deduced from comparing the crystal attachment energy with the adsorption energy of solvent or additive molecules is validated by SEM images of NBD micro-crystals in presence of the solvent alone or in presence of both additives. In conclusion, the EAMM approach appears to be a decisive tool for quickly simulating structural and habit properties of the molecular crystals, accessible or not by experimentation. Thus, a numerical selection of molecules becomes possible in view of deriving organic materials with predetermined properties, such as the fluorescence properties of the compound considered in the present study.
ISSN: 0022-0248

hal-00857894
https://hal.archives-ouvertes.fr/hal-00857894
DOI : 10.1016/j.jcrysgro.2011.07.035

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : The distribution of water and ions in nanoporous membranes, in particular close to their surfaces with external reservoirs, is investigated by means of molecular dynamics (MD) simulations using classical polarizable force fields. A sodium iodide (NaI) aqueous solution is considered in uncharged weakly hydrophilic (WH) and highly hydrophilic (HH) nanoporous materials modeled by a single truncated nanopore in contact with two reservoirs. In the inner part of the nanopore, the spatial distribution of water and ions is obtained by coupling semi-infinitesimal longitudinal and semi-infinitesimal radial descriptions. In the HH material, in contrast with the WH material, species are no longer uniformly distributed in the inner nanopore and water molecules are distributed in a nearly frozen axially periodic corona-like structure which leads to the formation of ionic tunnels. In the reservoirs, water molecules and ions attracted by the membrane surface create a necking of the confined solution which acts as a barrier at the entrance of the nanopore. In the WH nanopore subsurface, close to the surface of the membrane, the species distribution is analogous to the interface distribution between an aqueous electrolyte solution and air. In the HH nanopore subsurface, this distribution is modulated by the water corona-like structure. These results provide useful information for predicting properties of nanoporous membranes, in particular the drastic reduction of diffusion coefficients in HH materials, and give a guide to designing synthetic membranes for applications in nanofiltration, etc.
ISSN: 1932-7447

hal-00682155
https://hal.archives-ouvertes.fr/hal-00682155
DOI : 10.1021/jp2078924

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This work deals with the problem of finding for a given industrial target the molecule conformation leading to the most efficient crystal polymorph and/or designing unknown crystal packing of new molecules. The originality of the method relies first on constraining the domain of the most probable crystals, before converging towards the predicted packing by a double genetic-refining optimization algorithm. Validation of this approach is discussed on the case study of 46 energetic crystal compounds, using the semi Ab Initio and Molecular Mechanics code GenMol™. This validation shows that all observed structures are retrieved in any circumstances with a relatively high number of good rankings.
ISSN: 0022-0248

hal-00857875
https://hal.archives-ouvertes.fr/hal-00857875
DOI : 10.1016/j.jcrysgro.2009.04.002

Éditeur(s) : HAL CCSD European Centre for Disease Prevention and Control
Résumé : International audience
Following of the emergence of Zika virus in Brazil in 2015, an epidemiological surveillance system was quickly implemented in the French overseas Territories of America (FTA) according to previous experience with dengue and chikungunya and has detected first cases of Zika. General practitioners and medical microbiologists were invited to report all clinically suspectedcases of Zika, laboratory investigations were systematically conducted (RT-PCR). On 18 December, the first autochthonous case of Zika virus infection was confirmed by RT-PCR on French Guiana and Martinique, indicating introduction of Zika virus inFTA. The viral circulation of Zika virus was then also confirmed on Guadeloupe and Saint-Martin. We report here early findings on 203 confirmed cases of Zika virus infection identified by RT-PCR or seroneutralisation on Martinique Island between 24 November 2015 and 20 January 2016. All cases were investigated. Common clinical signs were observed (maculopapularrash, arthralgia, fever, myalgia and conjunctival hyperaemia) among these patients, but the rash, the foundation of our case definition, may be absent in a significant proportion of patients (16%). These results are important for the implementation of a suspected case definition, the main tool for epidemiological surveillance, in territories that may be affected by ZIKV emergence, including Europe.
ISSN: 1025-496X

Droits : info:eu-repo/semantics/OpenAccess
inserm-01415215
http://www.hal.inserm.fr/inserm-01415215
http://www.hal.inserm.fr/inserm-01415215/document
http://www.hal.inserm.fr/inserm-01415215/file/2016%2C%20Daudens-Vaysse%20-%20Zika%20emergence%20in%20the%20French%20Territories%20of%20America%20and%20description%20of%20first%20confirmed%20cases%20of%20Zika%20virus%20infection%20on%20Martinique%20.pdf
DOI : 10.2807/1560-7917.ES.2016.21.28.30285

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
CD95 ligand (CD95L) is expressed by immune cells and triggers apoptotic death. Metalloprotease-cleaved CD95L (cl-CD95L) is released into the bloodstream but does not trigger apoptotic signaling. Hence, the pathophysiological role of cl-CD95L remains unclear. We observed that skin-derived endothelial cells from systemic lupus erythematosus (SLE) patients expressed CD95L and that after cleavage, cl-CD95L promoted T helper 17 (Th17) lymphocyte transmigration across the endothelial barrier at the expense of T regulatory cells. T cell migration relied on a direct interaction between the CD95 domain called calcium-inducing domain (CID) and the Src homology 3 domain of phospholipase C gamma 1. Th17 cells stimulated with cl-CD95L produced sphingosine-1-phosphate (S1P), which promoted endothelial transmigration by activating the S1P receptor 3. We generated a cell-penetrating CID peptide that prevented Th17 cell transmigration and alleviated clinical symptoms in lupus mice. Therefore, neutralizing the CD95 non-apoptotic signaling pathway could be an attractive therapeutic approach for SLE treatment.
ISSN: 1074-7613

hal-01359568
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359568
DOI : 10.1016/j.immuni.2016.06.028
PUBMED : 27438772