10 research outputs found

    Association between adenovirus viral load and mortality in pediatric allo-hct recipients. the multinational advance study

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    This multivariable analysis from the AdVance multicenter observational study assessed adenovirus (AdV) viremia peak, duration, and overall AdV viral burden—measured as time-averaged area under the viremia curve over 16 weeks (AAUC0-16)—as predictors of all-cause mortality in pediatric allo-HCT recipients with AdV viremia. In the 6 months following allo-HCT, 241 patients had AdV viremia ≥ 1000 copies/ml. Among these, 18% (43/241) died within 6 months of first AdV ≥ 1000 copies/ml. Measures of AdV viral peak, duration, and overall burden of infection consistently correlate with all-cause mortality. In multivariable analyses, controlling for lymphocyte recovery, patients with AdV AAUC0-16 in the highest quartile had a hazard ratio of 11.1 versus the lowest quartile (confidence interval 5.3–23.6); for peak AdV viremia, the hazard ratio was 2.2 for the highest versus lowest quartile. Both the peak level and duration of AdV viremia were correlated with short-term mortality, independent of other known risk factors for AdV-related mortality, such as lymphocyte recovery. AdV AAUC0-16, which assesses both peak and duration of AdV viremia, is highly correlated with mortality under the current standard of care. New therapeutic agents that decrease AdV AAUC0-16 have the potential of reducing mortality in this at-risk patient population

    <NOTES>Schedule Rating System for the Insurance of Impaired Lives

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    Nanowires have the potential to play an important role for next-generation light-emitting diodes. In this work, we present a growth scheme for radial nanowire quantum-well structures in the AlGaInP material system using a GaInP nanowire core as a template for radial growth with GaInP as the active layer for emission and AlGaInP as charge carrier barriers. The different layers were analyzed by X-ray diffraction to ensure lattice-matched radial structures. Furthermore, we evaluated the material composition and heterojunction interface sharpness by scanning transmission electron microscopy energy dispersive X-ray spectroscopy. The electro-optical properties were investigated by injection luminescence measurements. The presented results can be a valuable track toward radial nanowire light-emitting diodes in the AlGaInP material system in the red/orange/yellow color spectrum

    Atomically sharp, crystal phase defined GaAs quantum dots

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    Crystal phase defined heterostructures, or polytype heterostructures, are atomically sharp with no intermixing, which makes them ideal contenders for a wide number of applications. Although polytype quantum dots have shown promising results as single photon sources, a high degree of control on the dimensions and number of polytype quantum dots is necessary before any application can be developed.In this work we show results from optical characterization of highly controlled wz-zb GaAs quantum dots with sharp photoluminescence signal and a strong indication of 0D density of states. One band effective mass calculations show good agreement with the measured data. Radially confined nanowires with a single wz-zb GaAs interface also show sharp photoluminescence signal and a 0D density of states. This indicates the existence of quantum dot like states in the triangular wells formed at the wz-zb GaAs interface. These results show the potential of polytype quantum dots for physics and optics applications

    Anti-Stokes photoluminescence probing k-conservation and thermalization of minority carriers in degenerately doped semiconductors

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    It has recently been found that anti-Stokes photoluminescence can be observed in degenerately n-doped indium phosphide nanowires, when exciting directly into the electron gas. This anti-Stokes mechanism has not been observed before and allows the study of carrier relaxation and recombination using standard photoluminescence techniques. It is important to know if this anti-Stokes photoluminescence also occurs in bulk semiconductors as well as its relation to carrier recombination and relaxation. Here we show that similar anti-Stokes photoluminescence can indeed be observed in degenerately doped bulk indium phosphide and gallium arsenide and is caused by minority carriers scattering to high momenta by phonons. We find in addition that the radiative electron-hole recombination is highly momentum-conserving and that photogenerated minority carriers recombine before relaxing to the band edge at low temperatures. These observations challenge the use of models assuming thermalization of minority carriers in the analysis of highly doped devices
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