A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles

Numerous luminophores may be encapsulated into silica nanoparticles (< 100 nm) using the reverse microemulsion process. Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring. Such nanospheres represent attractive nanoplatforms for the development of biotargeted biocompatible luminescent tracers. Physical and chemical properties of the encapsulated molecules may be affected by the nanomatrix. This study examines the synthesis of different types of dispersed silica nanoparticles, the ability of the selected luminophores towards incorporation into the silica matrix of those nanoobjects as well as the photophysical properties of the produced dye-doped silica nanoparticles. The nanoparticles present mean diameters between 40 and 60 nm as shown by TEM analysis. Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles. This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles

VDES J2325−5229 a z = 2.7 gravitationally lensed quasar discovered using morphology-independent supervised machine learning

We present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift zs = 2.74 and image separation of 2.9 arcsec lensed by a foreground zl = 0.40 elliptical galaxy. Since optical observations of gravitationally lensed quasars showthe lens system as a superposition of multiple point sources and a foreground lensing galaxy, we have developed a morphology-independent multi-wavelength approach to the photometric selection of lensed quasar candidates based on Gaussian Mixture Models (GMM) supervised machine learning. Using this technique and gi multicolour photometric observations from the Dark Energy Survey (DES), near-IR JK photometry from the VISTA Hemisphere Survey (VHS) and WISE mid-IR photometry, we have identified a candidate system with two catalogue components with iAB = 18.61 and iAB = 20.44 comprising an elliptical galaxy and two blue point sources. Spectroscopic follow-up with NTT and the use of an archival AAT spectrum show that the point sources can be identified as a lensed quasar with an emission line redshift of z = 2.739 ± 0.003 and a foreground early-type galaxy with z = 0.400 ± 0.002.We model the system as a single isothermal ellipsoid and find the Einstein radius θE ∼ 1.47 arcsec, enclosed mass Menc ∼ 4 × 1011 M and a time delay of ∼52 d. The relatively wide separation, month scale time delay duration and high redshift make this an ideal system for constraining the expansion rate beyond a redshift of 1

Etude observationnelle d'efficacité et de tolérance de l'aprépitant dans la prévention des nausées et vomissements induits par une chimiothérapie hautement émétisante (évaluation réalisée auprès de 100 patients au Centre Léon Bérard (Lyon))

LYON1-BU Santé (693882101) / SudocSudocFranceF

Comparison of three labeled silica nanoparticles used as tracers in transport experiments in porous media. Part I: Syntheses and characterizations

International audienc

Surface characterizations of fluorescent-functionalized silica nanoparticles: from the macroscale to the nanoscale

International audienceFluorescent silica nanoparticles are widely used for various applications from mechanical reinforcement to biology. In many cases, their surface has to be tailored. Herein fluorescent silica nanoparticles are synthesized by a reverse micro-emulsion process and functionalized by silane coupling agents owning amino and thiol groups. The functionalization is then characterized by macroscopic well-known methods (zeta potential, hydrophilic to hydrophobic ratio, etc.) and an original method based onto TEM observations of the contrast between the silica core and the metallic ions chelated by the functional groups grafted onto the surface is also introduced. This method reveals that the functionalization is effective and that it occurs by ''nano domains.'' It is therefore possible to characterize the functionalization by in situ observations. Finally, the characterized nanoparticles are incorporated into a PMMA thin film. The fluorescence of the nanoparticles allows the monitoring of the level of dispersion of the nanoparticles within the polymer and confirms all the other characterizations