University of Duisburg-Essen

About: University of Duisburg-Essen is a education organization based out in Essen, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 16072 authors who have published 39972 publications receiving 1109199 citations.

Embedded Interaction: Interacting with the Internet of Things

Abstract: The Internet of Things assumes that objects have digital functionality and can be identified and tracked automatically. The main goal of embedded interaction is to look at new opportunities that arise for interactive systems and the immediate value users gain. The authors developed various prototypes to explore novel ways for human-computer interaction (HCI), enabled by the Internet of Things and related technologies. Based on these experiences, they derive a set of guidelines for embedding interfaces into people's daily lives.

Size and surface charge of gold nanoparticles determine absorption across intestinal barriers and accumulation in secondary target organs after oral administration

Abstract: It is of urgent need to identify the exact physico-chemical characteristics which allow maximum uptake and accumulation in secondary target organs of nanoparticulate drug delivery systems after oral ingestion. We administered radiolabelled gold nanoparticles in different sizes (1.4-200 nm) with negative surface charge and 2.8 nm nanoparticles with opposite surface charges by intra-oesophageal instillation into healthy adult female rats. The quantitative amount of the particles in organs, tissues and excrements was measured after 24 h by gamma-spectroscopy. The highest accumulation in secondary organs was mostly found for 1.4 nm particles; the negatively charged particles were accumulated mostly more than positively charged particles. Importantly, 18 nm particles show a higher accumulation in brain and heart compared to other sized particles. No general rule accumulation can be made so far. Therefore, specialized drug delivery systems via the oral route have to be individually designed, depending on the respective target organ.

Interaction of colloidal nanoparticles with their local environment: the (ionic) nanoenvironment around nanoparticles is different from bulk and determines the physico-chemical properties of the nanoparticles

Abstract: The physico-chemical properties of colloidal nanoparticles (NPs) are influenced by their local environment, as, in turn, the local environment influences the physico-chemical properties of the NPs. In other words, the local environment around NPs has a profound impact on the NPs, and it is different from bulk due to interaction with the NP surface. So far, this important effect has not been addressed in a comprehensive way in the literature. The vicinity of NPs can be sensitively influenced by local ions and ligands, with effects already occurring at extremely low concentrations. NPs in the Huckel regime are more sensitive to fluctuations in the ionic environment, because of a larger Debye length. The local ion concentration hereby affects the colloidal stability of the NPs, as it is different from bulk owing to Debye Huckel screening caused by the charge of the NPs. This can have subtle effects, now caused by the environment to the performance of the NP, such as for example a buffering effect caused by surface reaction on ultrapure ligand-free nanogold, a size quenching effect in the presence of specific ions and a significant impact on fluorophore-labelled NPs acting as ion sensors. Thus, the aim of this review is to clarify and give an unifying view of the complex interplay between the NP's surface with their nanoenvironment.

Chronic inflammation promotes myeloid-derived suppressor cell activation blocking antitumor immunity in transgenic mouse melanoma model

Abstract: Tumor microenvironment is characterized by chronic inflammation represented by infiltrating leukocytes and soluble mediators, which lead to a local and systemic immunosuppression associated with cancer progression. Here, we used the ret transgenic spontaneous murine melanoma model that mimics human melanoma. Skin tumors and metastatic lymph nodes showed increased levels of inflammatory factors such as IL-1β, GM-CSF, and IFN-γ, which correlated with tumor progression. Moreover, Gr1+CD11b+ myeloid-derived suppressor cells (MDSCs), known to inhibit tumor reactive T cells, were enriched in melanoma lesions and lymphatic organs during tumor progression. MDSC infiltration was associated with a strong TCR ζ-chain down-regulation in all T cells. Coculturing normal splenocytes with tumor-derived MDSC induced a decreased T-cell proliferation and ζ-chain expression, verifying the MDSC immunosuppressive function and suggesting that the tumor inflammatory microenvironment supports MDSC recruitment and immunosuppressive activity. Indeed, upon manipulation of the melanoma microenvironment with the phosphodiesterase-5 inhibitor sildenafil, we observed reduced levels of numerous inflammatory mediators (e.g., IL-1β, IL-6, VEGF, S100A9) in association with decreased MDSC amounts and immunosuppressive function, indicating an antiinflammatory effect of sildenafil. This led to a partial restoration of ζ-chain expression in T cells and to a significantly increased survival of tumor-bearing mice. CD8 T-cell depletion resulted in an abrogation of sildenafil beneficial outcome, suggesting the involvement of MDSC and CD8 T cells in the observed therapeutic effects. Our data imply that inhibition of chronic inflammation in the tumor microenvironment should be applied in conjunction with melanoma immunotherapies to increase their efficacy.