130 research outputs found

    Donor-derived Strongyloides stercoralis hyperinfection syndrome after simultaneous kidney/pancreas transplantation

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    Most cases of strongyloidiasis associated with solid organ transplantation have been due to the reactivation of a latent infection in the recipient as a result of the immunosuppressive therapy; however, donor-derived infections are becoming increasingly frequent. The case of a patient who nearly died of a Strongyloides stercoralis hyperinfection after receiving simultaneous kidney/pancreas transplants is described herein. No specific parasitological tests were performed pre-transplantation, despite the fact that both the recipient and the donor originated from endemic areas. Serological analysis of the donor's serum performed retrospectively revealed the origin of the infection, which if it had been done beforehand would have prevented the serious complications. Current practice guidelines need to be updated to incorporate immunological and molecular techniques for the rapid screening of Strongyloides prior to transplantation, and empirical treatment with ivermectin should be applied systematically when there is the slightest risk of infection in the donor or recipient

    Stabilization of catalyst particles against sintering on oxide supports with high oxygen ion lability exemplified by Ir-catalyzed decomposition of N2O

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    Iridium nanoparticles deposited on a variety of surfaces exhibited thermal sintering characteristics that were very strongly correlated with the lability of lattice oxygen in the supporting oxide materials. Specifically, the higher the lability of oxygen ions in the support, the greater the resistance of the nanoparticles to sintering in an oxidative environment. Thus with γ-Al2O3 as the support, rapid and extensive sintering occurred. In striking contrast, when supported on gadolinia-ceria and alumina-ceria-zirconia composite, the Ir nanoparticles underwent negligible sintering. In keeping with this trend, the behavior found with yttria-stabilized zirconia was an intermediate between the two extremes. This resistance, or lack of resistance, to sintering is considered in terms of oxygen spillover from support to nanoparticles and discussed with respect to the alternative mechanisms of Ostwald ripening versus nanoparticle diffusion. Activity towards the decomposition of N2O, a reaction that displays pronounced sensitivity to catalyst particle size (large particles more active than small particles), was used to confirm that catalytic behavior was consistent with the independently measured sintering characteristics. It was found that the nanoparticle active phase was Ir oxide, which is metallic, possibly present as a capping layer. Moreover, observed turnover frequencies indicated that catalyst-support interactions were important in the cases of the sinter-resistant systems, an effect that may itself be linked to the phenomena that gave rise to materials with a strong resistance to nanoparticle sintering

    University Entrepreneurship and Professor Privilege

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    This paper analyzes how institutional differences affect university entrepreneurship. We focus on ownership of faculty inventions, and compare two institutional regimes; the US and Sweden. In the US, the Bayh-Dole Act gives universities the right to own inventions from publicly funded research,whereas in Sweden, the professor privilege gives the university faculty this right. We develop a theoretical model and examine the effects of institutional differences on modes of commercialization; entrepreneurship or licenses to established firms, as well as on probabilities of successful commercialization. We find that the US system is less conducive to entrepreneurship than the Swedish system if established firms have some advantage over faculty startups, and that on average the probability of successful commercialization is somewhat higher in the US. We also use the model to perform four policy experiments as suggested by recent policy debates in both countries

    Measurement of the 24Mg(p,t) 22Mg reaction and implications for the 21Na(p, γ) 22Mg stellar reaction rate

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    Levels in 22Mg between 4 and 7 MeV excitation energy have been populated in a high-resolution study of the 24Mg(p,t) 22Mg reaction. Two new states have been observed at energies Ex = 5090 and 6323 keV, while two states were observed at 5962 and 6046 keV. The precision in measured excitation energies for several other 22Mg levels has been improved substantially. In addition, a new state at 8141 keV was observed in 23Mg. Using spin and parity restrictions from the present and previous work, we discuss T = 1 analog state assignments of A = 22 nuclei below 7 MeV excitation energy. The implications for the rate of the stellar reaction 21Na(p, γ) 22Mg which takes part in hydrogen burning during nova outbursts are presented
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