Structure and Magnetism of well-defined cobalt nanoparticles embedded in a niobium matrix

Our recent studies on Co-clusters embedded in various matrices reveal that the co-deposition technique (simultaneous deposition of two beams : one for the pre-formed clusters and one for the matrix atoms) is a powerful tool to prepare magnetic nanostructures with any couple of materials even though they are miscible. We study, both sharply related, structure and magnetism of the Co/Nb system. Because such a heterogeneous system needs to be described at different scales, we used microscopic and macroscopic techniques but also local selective absorption ones. We conclude that our clusters are 3 nm diameter f.c.c truncated octahedrons with a pure cobalt core and a solid solution between Co and Nb located at the interface which could be responsible for the magnetically inactive monolayers we found. The use of a very diluted Co/Nb film, further lithographed, would allow us to achieve a pattern of microsquid devices in view to study the magnetic dynamics of a single-Co cluster.Comment: 7 TeX pages, 9 Postscript figures, detailed heading adde

Direct Observations of Oxygen-induced Platinum Nanoparticle Ripening Studied by In Situ TEM

This study addresses the sintering mechanism of Pt nanoparticles dispersed on a planar, amorphous Al2O3 support as a model system for a catalyst for automotive exhaust abatement. By means of in situ transmission electron microscopy (TEM), the model catalyst was monitored during the exposure to 10 mbar air at 650 degrees C. Time-resolved image series unequivocally reveal that the sintering of Pt nanoparticles was mediated by an Ostwald ripening process. A statistical analysis of an ensemble of Pt nanoparticles shows that the particle size distributions change shape from an initial Gaussian distribution via a log-normal distribution to a Lifshitz-Slyozov-Wagner (LSW) distribution. Furthermore, the time-dependency of the ensemble-averaged particle size and particle density is determined. A mean field kinetic description captures the main trends in the observed behavior. However, at the individual nanoparticle level, deviations from the model are observed suggesting in part that the local environment influences the atom exchange process

Recombinant factor VIII products and inhibitor development in previously untreated patients with severe haemophilia A: Combined analysis of three studies.

This is the peer reviewed version of the following article:Volkers, P, Hanschmann, K‐M, Calvez, T, et al. Recombinant factor VIII products and inhibitor development in previously untreated patients with severe haemophilia A: Combined analysis of three studies. Haemophilia. 2019; 25: 398– 407. https://doi.org/10.1111/hae.13747, which has been published in final form at https://doi.org/10.1111/hae.13747. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsINTRODUCTION: Standard treatment of congenital haemophilia A is based on replacement therapy with coagulation factor VIII (FVIII) products. A major complication of FVIII therapy is the occurrence of IgG alloantibodies (inhibitors) that neutralize FVIII activity. AIM: The aim of the analysis was estimating the risk of high-titre inhibitor associated with the second-generation full-length product compared to third-generation full-length product and other recombinant FVIII (rFVIII). METHODS: We conducted a combined analysis of individual patient data from three large studies in previously untreated patients (PUPs) with severe haemophilia A. RESULTS: A total of 1109 PUPs were treated from 1993 to 2013 including 787 PUPs treated from 2004 onwards (primary analysis cohort). A total of 322 patients (29.0%) developed an inhibitor, of which 192 (17.3%) a high-titre inhibitor. In the primary analysis set, 29.9% of patients developed an inhibitor and 17.2% a high-titre inhibitor. The combined analysis indicated a lower risk of high-titre inhibitor development for the third-generation rFVIII product compared to the second-generation rFVIII product (primary analysis: adjusted hazard ratio (HR) = 0.72, 95% CI: 0.49 to 1.06). Adjusted HR for all inhibitor development was significantly lower for the third-generation product compared to the second-generation product. CONCLUSION: The trend of an increased risk of inhibitor development in PUPs for one recombinant product illustrates that extrapolation from one recombinant factor VIII product to other products might not be justified.Paul‐Ehrlich‐Institu