Ultrafine heat-induced structural perturbations of bone mineral at the individual nanocrystal level

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COMPLIS experiments : COllaboration for spectroscopy Measurements using a Pulsed Laser Ion Source

Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments μ, spectroscopic quadrupole moments Qs and changes of the nuclear mean square charge radius δ〈rc 2〉along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented. (Springer

Self-assembled biotransesterified cyclodextrins as potential Artemisinin nanocarriers. II: In vitro behavior toward the immune system and in vivo biodistribution assessment of unloaded nanoparticles.

In a previous study, we reported on the formulation of Artemisinin-loaded surface-decorated nanoparticles (nanospheres and nanoreservoirs) by co-nanoprecipitation of PEG derivatives (PEG1500 and PEG4000-stearate, polysorbate 80) and biosynthesized γ-CD fatty esters. In the present study, the co-nanoprecipitation was extended to the use of a PEGylated phospholipid, namely DMPE-PEG2000. As our goal was to prepare long-circulating nanocarriers for further systemic delivery of Artemisinin (ART), here, we have investigated, on the one hand, the in vitro behavior of these surface-modified γ-CD-C10 particles toward the immune system (complement activation and macrophage uptake assays) and, on the other hand, their biodistribution features in mice. These experiments showed that the in vitro plasma protein adsorption and phagocytosis by macrophage cells triggered by γ-CD-C10 nanoparticles were significantly reduced when their surface was decorated with amphiphilic PEGylated molecules, in particular PEG1500-stearate, DMPE-mPEG2000 or polysorbate 80. The prolonged blood circulation time assessed by fluorescence imaging was demonstrated for unloaded γ-CD-C10-based nanospheres and nanoreservoir particles containing DMPE-PEG2000 and polysorbate80, respectively. These nanoparticles also proved to be non-hemolytic at the concentration range used in vivo. Within the limits of the conducted experiments, the co-nanoprecipitation technique may be considered as an alternative for surface modification of amphiphilic CD-based drug delivery systems and may be applied to the systemic delivery of ART

Stability of Self-Assembled Polymeric Micelles in Serum

The stability of polymeric nanoparticles in serum is critical to their use in drug delivery where dilution after intravenous injection often results in nanoparticle disassembly and drug unloading; however, few investigate this in biologically relevant media. To gain greater insight into nanoparticle stability in blood, the stability of self-assembled polymeric micelles of poly(d,l-lactide-co-2-methyl-2-carboxytrimethylene carbonate)-g-poly(ethylene glycol), P(LA-co-TMCC)-g-PEG, were tested in both serum and individual serum protein solutions. By encapsulating Förster resonance energy transfer pairs and following their release by fluorescence, these micelles demonstrated excellent thermodynamic and kinetic stability in the presence of serum. Further analyses by fast protein liquid chromatography and dynamic light scattering confirmed these data. Moreover, these micelles are compatible with red blood cells, as shown by a hemolysis assay. The stability and compatibility demonstrated in blood suggest that these micelles may be stable in vivo, which is critical for intravenous drug delivery applications. This comprehensive approach to understanding micelle stability and compatibility is broadly applicable

Molecular Structural Differences between Type-2-Diabetic and Healthy Glycogen

Glycogen is a highly branched glucose polymer functioning as a glucose buffer in animals. Multiple-detector size exclusion chromatography and fluorophore-assisted carbohydrate electrophoresis were used to examine the structure of undegraded native liver glycogen (both whole and enzymatically debranched) as a function of molecular size, isolated from the livers of healthy and db/db mice (the latter a type 2 diabetic model). Both the fully branched and debranched levels of glycogen structure showed fundamental differences between glycogen from healthy and db/db mice. Healthy glycogen had a greater population of large particles, with more α particles (tightly linked assemblages of smaller β particles) than glycogen from db/db mice. These structural differences suggest a new understanding of type 2 diabetes

The SPIRAL radioactive ion beam facility

This document describes the scientific goals as well as the technical choices of the SPIRAL project (Système de Production d'Ions Radioactifs et d'Accélération en Ligne)

HREM CHARACTERIZATION OF STRUCTURAL CHANGES IN A DEFORMED Σ = 9 (122) GRAIN BOUNDARY IN SILICON

D'importantes modifications structurales ont lieu en déformant, à températures relativement élevées (T >1020 K = 0.6 Tf), le joint Σ=9(122) parfait . Le coeur des dislocations élémentaires de Σ=9, produites à faible déformation, ainsi que la structure des joints de coïncidence d'angles supérieurs, produits à forte déformation, sont décrits grâce au modèle des unités structurales. On constate que la prédiction de l'evolution structurale du joint n'est pas immédiate et que le mélange d'unités structurales dépend des conditions de déformations.At relatively high temperature (T>1020 K = 0.6 Tm), the deformation of a perfect Σ=9(122) symmetrical grain boundary (GB) induced large changes in the initial structure. The structural unit model was used to describe the structure of elementaryΣ=9 DSC dislocations cores, produced at low strain, and higher tilt angle coincidence GB's, produced at large strain . It was shown that the prediction of the GB structural evolution was not so straightforward and that the mixing of structural units depended on the deformation conditions