Communautes ethno-confessionnelles et levantines a Istanbul au XXe siecle: Coexistence, reseaux de sociabilite et relations intercommunautaires au quartier de Pera

[Δε διατίθεται περίληψη / no abstract available

Communautes ethno-confessionnelles et levantines a Istanbul au XXe siecle: Coexistence, reseaux de sociabilite et relations intercommunautaires au quartier de Pera

[Δε διατίθεται περίληψη / no abstract available

The oxidative potential of differently charged silver and gold nanoparticles on three human lung epithelial cell types

BACKGROUND: Nanoparticle (NPs) functionalization has been shown to affect their cellular toxicity. To study this, differently functionalized silver (Ag) and gold (Au) NPs were synthesised, characterised and tested using lung epithelial cell systems. METHODS: Monodispersed Ag and Au NPs with a size range of 7 to 10 nm were coated with either sodium citrate or chitosan resulting in surface charges from -50 mV to +70 mV. NP-induced cytotoxicity and oxidative stress were determined using A549 cells, BEAS-2B cells and primary lung epithelial cells (NHBE cells). TEER measurements and immunofluorescence staining of tight junctions were performed to test the growth characteristics of the cells. Cytotoxicity was measured by means of the CellTiter-Blue ® and the lactate dehydrogenase assay and cellular and cell-free reactive oxygen species (ROS) production was measured using the DCFH-DA assay. RESULTS: Different growth characteristics were shown in the three cell types used. A549 cells grew into a confluent mono-layer, BEAS-2B cells grew into a multilayer and NHBE cells did not form a confluent layer. A549 cells were least susceptible towards NPs, irrespective of the NP functionalization. Cytotoxicity in BEAS-2B cells increased when exposed to high positive charged (+65-75 mV) Au NPs. The greatest cytotoxicity was observed in NHBE cells, where both Ag and Au NPs with a charge above +40 mV induced cytotoxicity. ROS production was most prominent in A549 cells where Au NPs (+65-75 mV) induced the highest amount of ROS. In addition, cell-free ROS measurements showed a significant increase in ROS production with an increase in chitosan coating. CONCLUSIONS: Chitosan functionalization of NPs, with resultant high surface charges plays an important role in NP-toxicity. Au NPs, which have been shown to be inert and often non-cytotoxic, can become toxic upon coating with certain charged molecules. Notably, these effects are dependent on the core material of the particle, the cell type used for testing and the growth characteristics of these cell culture model systems

Mittelalter im Labor

Mit diesem Band präsentiert das Schwerpunktprogramm 1173 der Deutschen Forschungsgemeinschaft „Integration und Desintegration der Kulturen im europäischen Mittelalter“ erste Ergebnisse seiner Arbeit. Von Anfang an war ihm die Aufgabe gestellt, das mittelalterliche Europa in transkultureller Perspektive und auf Wegen einer transdisziplinären Wissenschaft zu erforschen und zu begreifen. Immer ging es darum, die disziplinär verfassten Einzelwissenschaften durch transdisziplinäre Arbeit zu ergänzen. Das wissenschaftliche Anliegen des Programms ist es, das europäische Mittelalter von seinen geografischen Rändern und seinen kulturellen Differenzen her zu erforschen und zu beschreiben. Der holistischen Frage nach der Einheit Europas wird die innere Vielfalt als gegenständlicher Ausgangspunkt entgegengesetzt. Europa wird nicht als abgeschlossenes, kohärentes Gebilde verstanden, sondern als ein Kontinent, dessen permanente Austausch- und Wechselbeziehungen zwischen den verschiedenen Regionen und Kulturen überhaupt erst zur Ausbildung seiner charakteristischen Merkmale geführt haben

The oxidative potential of differently charged silver and gold nanoparticles on three human lung epithelial cell types

Background: Nanoparticle (NPs) functionalization has been shown to affect their cellular toxicity. To study this, differently functionalized silver (Ag) and gold (Au) NPs were synthesised, characterised and tested using lung epithelial cell systems. Methods: Monodispersed Ag and Au NPs with a size range of 7 to 10 nm were coated with either sodium citrate or chitosan resulting in surface charges from -50 mV to +70 mV. NP-induced cytotoxicity and oxidative stress were determined using A549 cells, BEAS-2B cells and primary lung epithelial cells (NHBE cells). TEER measurements and immunofluorescence staining of tight junctions were performed to test the growth characteristics of the cells. Cytotoxicity was measured by means of the CellTiter-Blue ® and the lactate dehydrogenase assay and cellular and cell-free reactive oxygen species (ROS) production was measured using the DCFH-DA assay. Results: Different growth characteristics were shown in the three cell types used. A549 cells grew into a confluent mono-layer, BEAS-2B cells grew into a multilayer and NHBE cells did not form a confluent layer. A549 cells were least susceptible towards NPs, irrespective of the NP functionalization. Cytotoxicity in BEAS-2B cells increased when exposed to high positive charged (+65-75 mV) Au NPs. The greatest cytotoxicity was observed in NHBE cells, where both Ag and Au NPs with a charge above +40 mV induced cytotoxicity. ROS production was most prominent in A549 cells where Au NPs (+65-75 mV) induced the highest amount of ROS. In addition, cell-free ROS measurements showed a significant increase in ROS production with an increase in chitosan coating. Conclusions: Chitosan functionalization of NPs, with resultant high surface charges plays an important role in NP-toxicity. Au NPs, which have been shown to be inert and often non-cytotoxic, can become toxic upon coating with certain charged molecules. Notably, these effects are dependent on the core material of the particle, the cell type used for testing and the growth characteristics of these cell culture model systems