University of Vienna

About: University of Vienna is a education organization based out in Vienna, Austria. It is known for research contribution in the topics: Population & Context (language use). The organization has 44686 authors who have published 95840 publications receiving 2907492 citations.

Extended focus depth for Fourier domain optical coherence microscopy

Abstract: We report on a new detection scheme for Fourier domain optical coherence microscopy that exhibits high transverse resolution along an axially extended focal range. Nearly constant transverse resolution of ∼1.5 μm along a focal range of 200 μm is experimentally verified with a maximum sensitivity of 105 dB. A broad-bandwidth Ti:sapphire laser allowed for an axial resolution of 3 μm in air.

Release of TiO2 Nanoparticles from Sunscreens into Surface Waters: A One-Year Survey at the Old Danube Recreational Lake

Abstract: Monitoring data are necessary for the future production of engineered nanomaterials and the development of regulations for nanomaterials. Therefore, it is necessary to develop methods that reliably detect and quantify nanomaterials in real-world systems at expectedly low concentrations. In this work we tested several methodological approaches to detect titanium dioxide nanomaterials released from sunscreen products into the Old Danube Lake (Vienna, Austria), which is heavily used for recreational activities like bathing and water sports during the summer season. During a 12-month period suspended particulate matter (SPM) was collected from the lake and analyzed using a combination of complementary techniques. By sampling at a location approximately 50 m from the nearest bathing area and at one meter depth from the water surface, we focused on the potentially mobile fraction of the released nanoparticles. We were able to identify titanium dioxide nanoparticles stemming from sunscreens in the suspended matt...

Polarization-sensitive optical coherence tomography of dental structures.

Abstract: Optical coherence tomography (OCT) has been developed during the last 10 years as a new noninvasive imaging tool and has been applied to diagnose different ocular and skin diseases. This technique has

Density functional study of CO on Rh(111)

Abstract: We present detailed density functional calculations for CO on Rh(111). At low coverage, the applied semilocal functionals clearly favor CO adsorption in the hollow site. This is in disagreement with experimental studies which all point towards atop adsorption at low coverage. The experimental assignment is confirmed by theoretical calculations of the vibrational frequencies and core level shifts at various coverages, ranging from $1∕9\phantom{\rule{0.5em}{0ex}}\text{to}\phantom{\rule{0.5em}{0ex}}3∕4$ $[(2\ifmmode\times\else\texttimes\fi{}2)\text{\ensuremath{-}}3\mathrm{C}\mathrm{O}]$ monolayer CO. For atop adsorption the calculated vibrational frequencies and the Rh surface core level shifts are indeed found to agree very well with experiment. To understand these controversial results, a molecular $\mathrm{GGA}+\mathrm{U}$ method is applied, which allows one to shift the CO $2\ensuremath{\pi}*$ orbital towards the vacuum level. This reduces the binding energy in the hollow site and brings the theoretical site preference in agreement with experiment. It is investigated how this molecular $\mathrm{GGA}+\mathrm{U}$ method influences the vibrational properties and the surface core level shifts. Furthermore, details on the molecular $\mathrm{GGA}+\mathrm{U}$ method are presented.

Blockade of PD-L1 (B7-H1) augments human tumor-specific T cell responses in vitro.

Abstract: Human tumors frequently escape immune destruction, despite the presence of cytotoxic T cells (CTL) recognizing tumor-associated antigens (TAA) We have previously shown that programmed death ligand-1 (PD-L1), a recently identified ligand of the B7 superfamily, is expressed on murine tumors and can inhibit antitumor immune responses To evaluate the clinical relevance of our animal model findings, we examined human tumors and tumor-specific T cells We found PD-L1 to be constitutively expressed on human renal cell carcinoma (RCC) cell lines and upregulated on human melanoma cell lines upon exposure to interferon-gamma Similarly, we found binding of anti-PD-L1 monoclonal antibody (mAb) on frozen sections from RCC and melanomas, but not on normal tissues The corresponding inhibitory receptor of PD-L1, PD-1, revealed a higher expression on tumor-infiltrating lymphocytes than on peripheral blood lymphocytes (PBL) from melanoma patients upon specific antigen stimulation Stimulation of PBL from healthy donors with peptide-loaded dendritic cells in the presence of anti-PD-L1 mAb altered neither the total T cell numbers after expansion, nor the percentage of peptide-specific CTL, when providing a T cell help by addition of cytokines However, when stimulating TAA-specific CTL and T helper cells with Ag-pulsed dendritic cells in the absence of exogenous cytokines, PD-L1 blockade increased the cytokine production Similar to the data achieved in the murine system, the blockade of PD-L1 on human tumors resulted in enhanced cytolytic activity of TAA-specific CTLs and cytokine production of TAA-specific T helper cells when interacting directly with the tumor In summary, our data suggest that PD-L1/PD-1 interactions negatively regulate T cell effector functions predominantly in the absence of exogenous cytokine support, indicating an important role for this pathway in tumor evasion