La Fondation Bosch et son action dans le domaine des relations franco-allemandes

Cette année est célébré le cinquantenaire du discours de Charles de Gaulle, et l’année prochaine, ce sera le traité de l’Élysée dont on commémorera l’anniversaire. Au sein du tandem franco-allemand, nous préférons aujourd’hui nous souvenir de victoires historiques et nous ne regrettons plus les défaites. Nous commençons à nous faire du souci lorsque nous percevons chez notre voisin des évolutions qui nuisent à l’amitié, qui affaiblissent le couple franco-allemand en Europe et mettent en dange..

Screening of two-photon activated photodynamic therapy sensitizers using a 3D osteosarcoma model

Photodynamic therapy (PDT) involves a photosensitizing agent activated with light to induce cell death. Two-photon excited PDT (TPE-PDT) offers numerous benefits compared to traditional one-photon induced PDT, including an increased penetration depth and precision. However, the in vitro profiling and comparison of two-photon photosensitizers (PS) are still troublesome. Herein, we report the development of an in vitro screening platform of TPE-PS using a 3D osteosarcoma cell culture. The platform was tested using three different two-photon (2P) active compounds - a 2P sensitizer P2CK, a fluorescent dye Eosin Y, and a porphyrin derivative (TPP). Their 2P absorption cross-sections (sigma(2PA)) were characterised using a fully automated z-scan setup. TPP exhibited a remarkably high sigma(2PA) at 720 nm (8865 GM) and P2CK presented a high absorption at 850 nm (405 GM), while Eosin Y had the lowest 2P absorption at the studied wavelengths (<100 GM). The cellular uptake of PS visualized using confocal laser scanning microscopy showed that both TPP and P2CK were internalized by the cells, while Eosin Y stayed mainly in the surrounding media. The efficiency of the former two TPE-PS was quantified using the PrestoBlue metabolic assay, showing a significant reduction in cell viability after two-photon irradiation. The possibility of damage localization was demonstrated using a co-culture of adipose derived stem cells together with osteosarcoma spheroids showing no signs of damage to the surrounding healthy cells after TPE-PDT

Fully automated z-scan setup based on a tunable fs-oscillator

The z-scan technique has become a standard method to measure 2-photon absorption (2PA) properties of materials used for 2-photon applications. Here we present a completely automated, easily tunable z;-scan setup for spectral scanning. An algorithm collecting the required laser beam parameters allows to reliably determine the optimal working window of newly synthesized 2PA photoinitiators (PI) used for two-photon polymerization (2PP) in a wide spectral range. A complete spectrum (3 measurements per wavelength in 10 nm steps) can be obtained within an hour. Matching the wavelength used for 2PP to the maximum 2PA significantly increased the 2PP performance of the system

How structure shapes dynamics: knowledge development in Wikipedia--a network multilevel modeling approach.

Using a longitudinal network analysis approach, we investigate the structural development of the knowledge base of Wikipedia in order to explain the appearance of new knowledge. The data consists of the articles in two adjacent knowledge domains: psychology and education. We analyze the development of networks of knowledge consisting of interlinked articles at seven snapshots from 2006 to 2012 with an interval of one year between them. Longitudinal data on the topological position of each article in the networks is used to model the appearance of new knowledge over time. Thus, the structural dimension of knowledge is related to its dynamics. Using multilevel modeling as well as eigenvector and betweenness measures, we explain the significance of pivotal articles that are either central within one of the knowledge domains or boundary-crossing between the two domains at a given point in time for the future development of new knowledge in the knowledge base