Vapor nucleation on ions

The different existing theories of heterogeneous nucleation on ions are examined and their predictions compared with the available experimental results. It is shown that neither theory predicts both accurate free enthalpies barrier to nucleation and correct catalytic potencies of positive and negative ions. Finally, in view of some recent experiments, the existence itself of any sign effect is questionned

Colossal Dielectric and Electromechanical Responses in Self Assembled Polymeric Nanocomposites

An electroactive polymer nanocomposite, in which high dielectric constant copper phthalocyanine oligomer (o-CuPc) nanoparticles are incorporated into the block polyurethane (PU) matrix by the combination of “top down” and “bottom up” approaches, was realized. Such an approach enables the nanocomposite to exhibit colossal dielectric and electromechanical responses with very low volume fraction of the high dielectric constant o-CuPc nanofillers (~3.5%) in the composite. In contrast, a simple blend of o-CuPc and PU composite with much higher o-CuPc content (~16% of o-CuPc) shows much lower dielectric and electromechanical responses

Use of synchrotron radiation in plastics analysis

We demonstrate the application of synchrotron small angle X-ray scattering (SAXS) in measuring the thermodynamic properties of polymer blends. The polymers under investigation consist of poly(cyclohexyl acrylate) (PCHA) blended with the ortho and meta isomer of poly(bromostyrene) (P2BrS, P3BrS). Measurements of the absolute scattered intensity enable the determination of the second derivative of the Gibbs free energy of mixing with respect to the concentration, the location of the spinodal temperature, and the Flory-Huggins χ-parameter

Longitudinal chemokine profile expression in a blood-brain barrier model from Alzheimer transgenic versus wild-type mice

Abstract Background Alzheimer’s disease is widely described since the discovery of histopathological lesions in Mrs. Auguste Deter in 1906. However to date, there is no effective treatment to deal with the many cellular and molecular alterations. The complexity is even higher with the growing evidence of involvement of the peripheral blood mononuclear cells (PBMCs). Indeed, monocytes and T cells are shown in the cerebral parenchyma of AD patients, and these cells grafted to the periphery are able to go through the blood-brain barrier (BBB) in transgenic mouse models. It is known that BBB is disrupted at a late stage of AD. Chemokines represent major regulators of the transmigration of PBMCs, but many data were obtained on AD animal models. No data are available on the role of AD BBB in a healthy brain parenchyma. Therefore, the purpose of this study was to analyze the longitudinal chemokine profile expression in a BBB model from AD transgenic mice versus wild-type (WT) mice. Methods A primary mouse BBB model was used with a luminal compartment either AD or WT and an abluminal compartment WT consisting of astrocytes and microglia. PBMCs were extracted by a ficoll gradient and incubated in the transwell with a direct contact with the luminal side, including the endothelial cells and pericytes. Then, the complete BBB model was incubated during 48 h, before supernatants and cell lysates were collected. Chemokines were quantified by X-MAP® luminex technology. Results Abluminal CX3CL1 production increased in 12-month-old AD BBB while CX3CL1 levels decreased in luminal lysates. CCL3 in luminal compartment increased with aging and was significantly different compared to AD BBB at 12 months. In addition, abluminal CCL2 in 12-month-old AD BBB greatly decreased compared to levels in WT BBB. On the contrary, no modification was observed for CCL4, CCL5, and CXCL10. Conclusion These first findings highlighted the impact of AD luminal compartment on chemokine signature in a healthy brain parenchyma, suggesting new therapeutic or diagnostic approaches