Effect of chromophore-chromophore electrostatic interactions in the NLO response of functionalized organic-inorganic sol-gel materials

In the last years, important non-linear optical results on sol-gel and polymeric materials have been reported, with values comparable to those found in crystals. These new materials contain push-pull chromophores either incorporated as guest in a high Tg polymeric matrix (doped polymers) or grafted onto the polymeric matrix. These systems present several advantages; however they require significant improvement at the molecular level - by designing optimized chromophores with very large molecular figure of merit, specific to each application targeted. Besides, it was recently stated in polymers that the chromophore-chromophore electrostatic interactions, which are dependent of chromophore concentration, have a strong effect into their non-linear optical properties. This has not been explored at all in sol-gel systems. In this work, the sol-gel route was used to prepare hybrid organic-inorganic thin films with different NLO chromophores grafted into the skeleton matrix. Combining a molecular engineering strategy for getting a larger molecular figure of merit and by controlling the intermolecular dipole-dipole interactions through both: the tuning of the push-pull chromophore concentration and the control of TEOS (Tetraethoxysilane) concentration, we have obtained a r33 coefficient around 15 pm/V at 633 nm for the classical DR1 azo-chromophore and a r33 around 50 pm/V at 831 nm for a new optimized chromophore structure.Comment: 10 pages, 11 figures, 1 tabl

Magnetically textured y-Fe2O3 nanoparticles in a silica gel matrix: structural and magnetic properties

International audienceThis paper is devoted to magnetic and structural properties of anisotropic g -Fe2O3 superparamagnetic particles dispersed in a transparent xerogel matrix. The effect of frozen anisotropy axes and magnetic texture, induced by a magnetic field applied during the solidification of the matrix on the in-field magnetization process, is studied by alternating gradient force magnetometry and first and second order magneto-optical effects. The changes of magnetization curves with respect to the ferrofluid solution at the same particle concentration are interpreted on the basis of an existing statistical approach extended to systems with particle size distribution, which has to be taken into account for real samples. A very good agreement between the experiment and theory was achieved for a log-normal distribution of diameters which well resembles that deduced from electron microscopy observations in different imaging modes. This structural analysis states the parameter values used in calculations and confirms the relevance of basic assumptions of the model for the specimens studied. The experimental results and the related theoretical discussion should be of use to understand magnetic properties of other magnetically textured superparamagnetic system

Toward a Romanian version of the Three Factor Eating Questionnaire–R21 for children and adolescents (CTFEQr21): Preliminary psychometric analysis and relation with body composition

YesPurpose. The aim of this study was to develop and validate a Romanian version of the three factor eating questionnaire-r21 for children and adolescents (ctfeqr21), and to assess its psychometric properties and factor structure. Associations between this version of the ctfeqr21 and anthropometric measures as well as body composition were also examined. Design and methods. 153 children and adolescents (68 boys and 95 girls; 10.8 ± 3.5 years) took part in this study (bmi of 17.7 ± 3.1 kg/m²). The participants were first interviewed to ascertain their understanding of the ctfeq-r21 and were then asked to self-complete the questionnaire. Height and weight were measured and body composition assessed using bio impedance analyzers (Tanita MC 780). Results. The CTFEQr21 showed satisfactory internal consistency (cronbach’s α=0.78). Cronbach’s alpha coefficients were 0.55 for CR, 0.75 for UE, and 0.76 for EE separately. UE and EE were found to be significantly correlated (r=0.54, p<0.05). The three factors explained 43% of the total variance. Correlation between CR, UE and EE with body weight, BMI and FFM were significant but low to moderate with coefficients ranging from 0.20 to 0.37. The higher the CR, UE and EE tertiles, the higher the weight, fat mass (kg) and fat-free mass values. Conclusions. According to the psychometric analysis of the questionnaire, the proposed version of the CTFEQr21 proposed here is a satisfactory tool to assess eating behaviors in Romanian child population that remains to be further developed

Genetic diversity and taxonomic aspects of wild carrot in France

If in France, genetic resources of cultivated carrot are well studied and preserved, the wild compartment of the species remains unknown and underutilized, while there are many populations of wild carrot on the French territory. Several collecting missions were undertaken from 2009 to 2013 to identify and collect populations, particularly in coastal areas, in continental France and Corsica. More than a hundred populations were collected, with a good distribution throughout the territory, and eleven taxa were identified. The status of these taxa is variable, with some very common and others underrepresented or specific to a given area. Morphological and molecular studies are developed in order to improve the knowledge of taxonomy and diversity. The study conducted with microsatellite markers showed a high genetic diversity at the intra-and inter-populations levels. The overall results show that the Mediterranean coast and Corsica exhibit a particularly high diversity. The work confirms the specific interest of some populations and the taxonomic separation into 2 subgroups carota and gummifer in Daucus carota L. This study will allow developing a strategy for management of genetic resources and their valorisation in breeding

Combined strategy based on pre-activated analogs of oxazaphosphorines for increased therapeutic index and immune modulation

Oxazaphosphorines (Oxaza) represented by cyclophosphamide (CPA) and ifosfamide (IFO) are still the corner stone of several polychemotherapy protocols as they are widely indicated in the treatment of numerous cancer from soft tissue sarcomas to lymphomas and immune-related diseases. However, Oxaza are prodrugs requiring cytochrome (CYP) P450 bioactivation responsible of limiting adverse effects. In the case of IFO, bioactivation leads to a low release of 4-OH-IFO (10%), which generates the active nitrogen mustard displaying DNA cross-links. Associated toxicities of IFO due to acrolein, (urotoxicity) and to chloroacetaldehyde (neuro and nephrotoxicity) have been described. Thus, increasing IFO therapeutic index could be of major interest. To circumvent these toxicities, our team has designed new pre-activated IFO analogs to avoid CYP bioactivation (Skarbek et al J Med Chem 2015). Among these analogues some have the ability to self-assemble as nanoassemblies (NAs), the others can be encapsulated within nano-lipid capsules (NLCs). These new drug delivery systems (DDS) can take advantage of passive targeting, as stealthiness of these DDS can be provided by PEGylation by using Cholesterol-polyethylene glycol or the use of surfactant. These DDS can also be functionalized by appropriate monoclonal antibodies leading to multi stage DDS with active targeting properties. Regarding CPA, it has been shown and described in literature that low doses of CPA enhance the immunity by promoting differentiation of CD4⁺ cell toward Th1. As IFO is isomeric form of CPA, it was assumed that IFO could also have such properties. Studies on immunocompetent MCA205 mouse model, an immunogenic fibrosarcoma mouse model, demonstrate a dose-dependent immunomodulation of IFO towards a modulation of the secretion of IFNy, IL-17A and IL-6 cytokines. The ongoing experiments on mouse model depleted in CD4⁺ T cells and CD8⁺ T cells show the antitumor efficacy of IFO 150mg/kg on these immune cells in tumor regression. Both strategies could lead to the design of nano-immuno-conjugates (NICs) which could benefit of the immunomodulatory effects of X-Oxaza combined to their antiproliferative properties targeted through immune checkpoint antibodies. These new functionalized DDS may provide a useful strategy to give specificity to active drugs used for many years in clinical practice. Both DDS could be grafted with mAbs which could lead to a new family of DDS aiming to combine antiproliferative and immunomodulatory properties for a dual antitumoral action Citation Format: Julia Delahousse, Charles Skarbek, Valentine Gauthier, M Desbois, Emilie Roger, C. Pioche-Durieu, M. Rivard, D. Desmaële, T. Martens, E. LeCam, Jean-Pierre Benoit, P. Couvreur, Nathalie Chaput-Gras, Angelo Paci. Combined strategy based on pre-activated analogs of oxazaphosphorines for increased therapeutic index and immune modulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2195. doi:10.1158/1538-7445.AM2017-219

Le compartiment sauvage de la carotte en France : des ressources génétiques importantes et pourtant méconnues

La France est considérée comme centre secondaire de diversification de la carotte, du fait de l’activité importante de sélection (par des maraîchers ou semenciers), ce qui justifie les actions de conservation et connaissance des variétés anciennes menées par le réseau de ressources génétiques « Carotte et autres Daucus ». Par contre, le compartiment sauvage est méconnu et sous-exploité, alors qu’il s’agit d’une espèce pour laquelle de nombreuses populations existent sur le territoire français, avec une situation très contrastée. Si la carotte sauvage D. carota spp carota n’est pas en danger, d’autres sous espèces sont protégées (ssp gadecaei) ou menacées du fait de la dégradation de leur milieux naturels notamment en zone littorale ou de possibles introgressions avec la sous-espèce carota. Le travail présenté porte donc sur : i/ la sauvegarde et la mise à disposition des ressources génétiques sauvages, à travers l’inventaire de populations in situ et la constitution de collections ex-situ ; ii/ l’approfondissement de la connaissance et de l’identification taxonomique des sous-espèces sauvages ; iii/ la connaissance de la diversité au sein du compartiment sauvage (marqueurs SSR et données écologiques) ; et iv/ l’évaluation des ressources génétiques sauvages de carotte pour permettre leur exploitation (fertilité, croisements avec le compartiment cultivé, tolérance à différents bioagresseurs). Ce programme fait l’objet du soutien d’un contrat de branche du ministère de l’agriculture et implique les membres du réseau « Carotte et autres Daucus ».

S.A.X.S. STUDY OF NASIGEL AND NASIGLAS (SODIUM SUPERIONIC GELS AND GLASSES)

Des gels monolithiques ont été préparés dans le système Na2O-ZrO2-SiO2-P2O5, par la méthode sol/gel, (hydrolyse - polycondensation d'alkoxydes). L'évolution structurale pendant la gélification et la transition gel/verre a été étudiée par diffusion centrale de rayons X pour deux compositions. Des inhomogénéités peuvent exister dans le gel, elles correspondent probablement à la présence de clusters de zircone cubique qui se dissolvent progressivement dans la matrice silicatée lors de la transition gel/verre.Monolithic gels have been prepared in the Na2O-ZrO2-SiO2-P2O5 system by a low temperature chemical polymerization from metal or non metal alkoxide hydrolysis. We present here, for two typical compositions, structural results from a small angle X-ray scattering study (S.A.X.S.), concerning sol/gel, gel/xerogel and xerogel/glass transitions. Gels can exhibit inhomogeneities, probably due to cubic zirconia clusters, which progressively disappear during the gel/glass conversion

A GaAs data-path compiler

This paper deals with a GaAs data-path compiler for the public domain ALLIANCE CAD SYSTEM[l]. Based upon macro cells generators, cells libraries, and software tools, it provides a fast and easy way to describe and implement bit-sliced structures for DCFL logic. The use of over cells-routing, power supplies sharing and multiple access termi­nals coupled to a symbolic approach leads to a high density portable layout