Vrije Universiteit Brussel

About: Vrije Universiteit Brussel is a education organization based out in Brussels, Belgium. It is known for research contribution in the topics: Population & Context (language use). The organization has 14295 authors who have published 38258 publications receiving 1203970 citations. The organization is also known as: VUB.

Clastogenic and aneugenic effects of multi-wall carbon nanotubes in epithelial cells.

Abstract: Information on the toxicity of carbon nanotubes is still fragmentary but indicates that these particles can induce adverse effects. We previously demonstrated in rats that, when purified multi-wall carbon nanotubes (MWCNT) reach the lung, they are biopersistent and induce lung inflammation as well as fibrosis. The present study was designed to address the genotoxic potential of this material in the same species. In vivo, micronuclei (MN) were assessed in type II pneumocytes 3 days after a single intra-tracheal administration of MWCNT (0.5 or 2 mg). We also used the cytokinesis-block micronucleus assay in rat lung epithelial cells exposed in vitro to MWCNT (10, 25, 50 mug/ml). Finally, we applied a human pancentromeric fluorescent probe (fluorescent in situ hybridization assay) to differentiate clastogenic and/or aneugenic mechanisms in a human epithelial cell line (MCF-7). In vivo, we found a significant and dose-dependent increase in micronucleated pneumocytes after a single administration of MWCNT ( approximately a 2-fold increase at the highest dose). In vitro, we observed a significant increase of MN in epithelial cells after exposure to MWCNT (up to a 2-fold increase at the cytotoxic dose of 50 mug/ml). Finally, we found that MWCNT induced both centromere-positive and -negative MN in MCF-7 cells. Overall, this study provides the first evidence of the potential of MWCNT to induce clastogenic as well as aneugenic events.

Zero-lag long-range synchronization via dynamical relaying.

Abstract: We show that isochronous synchronization between two delay-coupled oscillators can be achieved by relaying the dynamics via a third mediating element, which surprisingly lags behind the synchronized outer elements. The zero-lag synchronization thus obtained is robust over a considerable parameter range. We substantiate our claims with experimental and numerical evidence of such synchronization solutions in a chain of three coupled semiconductor lasers with long interelement coupling delays. The generality of the mechanism is validated in a neuronal model with the same coupling architecture. Thus, our results show that zero-lag synchronized chaotic dynamical states can occur over long distances through relaying, without restriction by the amount of delay.