1,875 research outputs found

    Schistosomiasis and malignancy

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    It is generally accepted that schistosomiasis, if not causative, is at least associated with malignancy. In this review, the epidemiology of schistosomiasis and bladder carcinoma, as well as the role of chronic bladder infection, are discussed togetherwith known carcinogenic factors, possible abnormal vitamin metabolism and/or deficiencies and factors that influence conjugated carcinogens. Experimental evidence is briefly examined and recent work from the Far East on schistosomiasis and colon carcinoma reviewed

    Correlated Disorder Substrate‐Integrated Nanodisk Scatterers for Light Extraction in Organic Light Emitting Diodes

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    A major loss mechanism in organic light emitting diodes (OLEDs) is the coupling of the emitter molecule light field to waveguide modes in the OLED thin film stack. In this work, a disordered 2D array of TiO2_{2} nanodisk scatterers is integrated into the OLED substrate to enable efficient light extraction from these waveguide modes. Fabrication of the nanodisks is based on a bottom-up, colloidal lithography technique and subsequent pattern transfer into high refractive index TiO2_{2} via reactive ion etching. The substrates are completed by spin-coating a polymer planarization layer before applying the OLED thin film stack. This ensures reproducible optoelectronic properties of the OLED through leaving the electrically active layers planar. Simultaneously, the nanodisks in close vicinity to the thin film stack ensure efficient out-of-plane scattering of waveguide modes. In a monochromatic OLED (center wavelength λ0_{0} = 520 nm), a 44.2%rel_{rel} increase in external quantum efficiency is achieved in comparison to a device without scattering structure. An in-depth numerical analysis reveals that this significant enhancement is only partly due to the out-coupling of waveguide modes. Additional enhancement is suspected to result from out-coupling of substrate modes through scattering by the nanodisks. Further improvements to the scattering structure are numerically evaluated

    Low-energy dynamics of the γγππ\gamma\gamma\to\pi\pi reaction

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    We calculate the one-quark-loop amplitude for the low energy γγππ\gamma\gamma\to\pi\pi collision in the context of the Nambu and Jona-Lasinio model with scalar and pseudoscalar four quark couplings to all orders in the external momenta. We show that the NJL predictions for the γγπ+π\gamma\gamma\to\pi^+\pi^- reaction are not far from the Born amplitude, which is close to the data, and is compatible with the chiral perturbation theory estimations. We determine the corrections given by the NJL model in leading order of 1/Nc1/N_c to the chiral loop amplitude for γγπ0π0\gamma\gamma\to\pi^0\pi^0. Numerical results for the γγππ\gamma\gamma\rightarrow\pi\pi cross sections and for pion polarizabilities are given.Comment: 20 pages in LaTex, 3 figures in 1 Postscript fil
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