Infection frequently triggers thrombotic microangiopathy in patients with preexisting risk factors : a single-institution experience

Thrombotic microangiopathies are rare conditions characterized by microangiopathic hemolytic anemia, microthrombi, and multiorgan insult. The disorders, which include hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, are often acute and life threatening. We report a retrospective analysis of 65 patients presenting to our institution from 1997 to 2008 with all forms of thrombotic microangiopathy. Therapeutic plasma exchange was a requirement for analysis and 65 patients were referred to our institution; 66% of patients were female and median age at presentation was 52 years. Bacterial infection was the most commonly identified etiologic factor and in the multivariate model was the only significant variable associated with survival outcome (odds ratio 5.1, 95% confidence interval, 1.2-21.7). As infection can be considered a common trigger event for thrombotic microangiopathy, patients with hepatobiliary sepsis may benefit from elective cholecystectomy. We conclude that bacterial infection frequently triggers TTP and other thrombotic microangiopathies in patients with preexisting risk factors and propose a model for the development of these syndromes

FPGA implementation of a cyclostationary detector for OFDM signals

Due to the ubiquity of Orthogonal Frequency Division Multiplexing (OFDM) based communications standards such as IEEE 802.11 a/g/n and 3GPP Long Term Evolution (LTE), a growing interest has developed in techniques for reliably detecting the presence of these signals in dynamic radio systems. A popular approach for detection is to exploit the cyclostationary nature of OFDM communications signals. In this paper, we focus on a frequency domain cyclostationary detection algorithm first introduced by Giannakis and Dandawate and study its performance in detecting IEEE 802.11a OFDM signals in the presence of practical radio impairments such as Carrier Frequency offset (CFO), Phase Noise, I/Q Imbalance, Multipath Fading and DC offset. We then present a hardware implementation of this algorithm developed using MathWorks HDL Coder and provide implementation results after targeting to a Xilinx 7 Series FPGA device

International Regulatory Regimes for Nanotechnology

This paper represents a very early stage of a collaborative research project on transnational NT regulation. In this project, we seek to apply a multidisciplinary perspective to the question of regulation of nanotechnology (NT). We begin in Section I by considering the nature of NT and some risks it may pose as it is more fully developed and utilized over time. We next consider the nature of transnational "regulation," suggesting the range of legal, institutional and substantive forms this term can encompass. Because NT and its regulation are (like our project) at such early stages of development, we emphasize the importance of regulatory flexibility. In Section II, we consider a series of strategic choices that must be faced in designing transnational regulation in any issue area, including NT; these include the level and scope of regulation, the actors authorized to promulgate regulatory norms, the legal and institutional form of regulation, and finally its substantive content. In Section III, we argue that it is useful, although not definitive, to study models of transnational regulation developed for similar issues arising out of other forms of technology. While few if any of these models will be directly applicable to the unique characteristics of NT, the designers of these regulatory regimes faced similar strategic choices as well as similar problems, and the models they created can offer useful lessons. We briefly discuss a few potential models to illustrate the approach. Our larger research project will expand the study of transnational models beyond those discussed here, with a view to developing more specific recommendations for NT regulation. Consistent with our emphasis on regulatory flexibility, we conclude by tentatively suggesting a sequencing of regulatory approaches designed to allow NT regulation to develop over time into broader, more elaborate and more highly legalized form as we gain greater knowledge of, and experience with, the benefits and costs of NT

International Regulatory Regimes for Nanotechnology

This paper represents a very early stage of a collaborative research project on transnational NT regulation. In this project, we seek to apply a multidisciplinary perspective to the question of regulation of nanotechnology (NT). We begin in Section I by considering the nature of NT and some risks it may pose as it is more fully developed and utilized over time. We next consider the nature of transnational "regulation," suggesting the range of legal, institutional and substantive forms this term can encompass. Because NT and its regulation are (like our project) at such early stages of development, we emphasize the importance of regulatory flexibility. In Section II, we consider a series of strategic choices that must be faced in designing transnational regulation in any issue area, including NT; these include the level and scope of regulation, the actors authorized to promulgate regulatory norms, the legal and institutional form of regulation, and finally its substantive content. In Section III, we argue that it is useful, although not definitive, to study models of transnational regulation developed for similar issues arising out of other forms of technology. While few if any of these models will be directly applicable to the unique characteristics of NT, the designers of these regulatory regimes faced similar strategic choices as well as similar problems, and the models they created can offer useful lessons. We briefly discuss a few potential models to illustrate the approach. Our larger research project will expand the study of transnational models beyond those discussed here, with a view to developing more specific recommendations for NT regulation. Consistent with our emphasis on regulatory flexibility, we conclude by tentatively suggesting a sequencing of regulatory approaches designed to allow NT regulation to develop over time into broader, more elaborate and more highly legalized form as we gain greater knowledge of, and experience with, the benefits and costs of NT

Phonon Density of States and Anharmonicity of UO2

Phonon density of states (PDOS) measurements have been performed on polycrystalline UO2 at 295 and 1200 K using time-of-flight inelastic neutron scattering to investigate the impact of anharmonicity on the vibrational spectra and to benchmark ab initio PDOS simulations performed on this strongly correlated Mott-insulator. Time-of-flight PDOS measurements include anharmonic linewidth broadening inherently and the factor of ~ 7 enhancement of the oxygen spectrum relative to the uranium component by the neutron weighting increases sensitivity to the oxygen-dominated optical phonon modes. The first-principles simulations of quasi-harmonic PDOS spectra were neutron-weighted and anharmonicity was introduced in an approximate way by convolution with wavevector-weighted averages over our previously measured phonon linewidths for UO2 that are provided in numerical form. Comparisons between the PDOS measurements and the simulations show reasonable agreement overall, but they also reveal important areas of disagreement for both high and low temperatures. The discrepancies stem largely from an ~ 10 meV compression in the overall bandwidth (energy range) of the oxygen-dominated optical phonons in the simulations. A similar linewidth-convoluted comparison performed with the PDOS spectrum of Dolling et al. obtained by shell-model fitting to their historical phonon dispersion measurements shows excellent agreement with the time-of-flight PDOS measurements reported here. In contrast, we show by comparisons of spectra in linewidth-convoluted form that recent first-principles simulations for UO2 fail to account for the PDOS spectrum determined from the measurements of Dolling et al. These results demonstrate PDOS measurements to be stringent tests for ab initio simulations of phonon physics in UO2 and they indicate further the need for advances in theory to address lattice dynamics of UO2.Comment: Text slightly modified, results unchange