4,779 research outputs found

    Phase-resolved Crab Studies with a Cryogenic TES Spectrophotometer

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    We are developing time- and energy-resolved near-IR/optical/UV photon detectors based on sharp superconducting-normal transition edges in thin films. We report observations of the Crab pulsar made during prototype testing at the McDonald 2.7m telescope with a fiber-coupled transition-edge sensor (TES) system. These data show substantial (d[alpha]~0.3), rapid variations in the spectral index through the pulse profile, with a strong phase-varying IR break across our energy band. These variations correlate with X-ray spectral variations, but no single synchrotron population can account for the full Spectral Energy Distribution (SED). We also describe test spectrophotopolarimetry observations probing the energy dependence of the polarization sweep; this may provide a new key to understanding the radiating particle population.Comment: 12 pages, 10 figures -- to appear in ApJ V56

    The Polytetrafluoroethylene (PTFE) Graft for Portacaval Interposition: An Experimental Observation

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    In an attempt to determine the efficacy of the polytetrafluoroethylene (PTFE) graft as a portacaval interposition shunt, 26 mongrel dogs were randomly selected to receive a side-to-side shunt with a 6 mm, 8 mm, or 10 mm PTFE graft after portal hypertension had been created by hepatic vein ligation. The dogs were clinically observed, and if they showed signs of graft occlusion, they were reexplored surgically. The 6 mm graft had a 0% patency rate; the 8 mm graft had a 28.6% patency rate; and the 10 mm graft had an 87.5% patency rate. Histological examinations revealed adequate incorporation of the graft, formation of an endothelial layer, and absence of a thick intimal layer. In this experimental model, the PTFE graft served as a satisfactory portacaval interposition shunt when the 10 mm graft was used

    Surgical Treatment of Portal Hypertension: Review of Henry Ford Hospital Experience

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    Of 146 operations performed for the complications of portal hypertension in the Henry Ford Hospital between 1927 and August 31, 1969, 114 were portasystemic shunts. Operative mortality, sequelae and long term survival were closely related to the state of the patients\u27 liver function and the urgency of operation

    An antimicrobial impregnated urinary catheter that reduces mineral encrustation and prevents colonisation by multi-drug resistant organisms for up to 12 ā€Æweeks

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    Two major complications of indwelling urinary catheterisation include infection and mineral encrustation of the catheter. Our antimicrobial urinary catheter (AUC) impregnated with rifampicin, triclosan, and sparfloxacin has demonstrated long-term protective activity against major uropathogens. This study aimed to firstly assess the ability of the AUC to resist mineral encrustation in the presence and absence of bacteria. Secondly, it aimed to investigate the AUCā€™s anti-biofilm activity against multi-drug resistant organisms. There was no difference in surface roughness between AUC and control segments. In a static and a perfusion model, phosphate deposition was significantly reduced on AUCs challenged with P. mirabilis. Furthermore, none of the AUCs blocked during the 28 day test period, unlike controls. The AUC prevented colonisation by methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, extended-spectrum beta-lactamase producing E. coli, and carbapenemase-producing E. coli for 12 consecutive weekly challenges. All three drugs impregnated into the catheter continued to exert protective activity throughout 12 weeks of constant perfusion. The drugs appear to migrate into the crystalline biofilm to continually protect against bacteria not it direct contact with the catheter surface. In conclusion, the AUC reduces mineral encrustation and may increase time to blockage in the presence of P. mirabilis, and does not predispose to mineral deposition under other conditions. It also offers 12 weeks of protection against multi-drug resistant bacteria

    Screening vaccine formulations for biological activity using fresh human whole blood.

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    Understanding the relevant biological activity of any pharmaceutical formulation destined for human use is crucial. For vaccine-based formulations, activity must reflect the expected immune response, while for non-vaccine therapeutic agents, such as monoclonal antibodies, a lack of immune response to the formulation is desired. During early formulation development, various biochemical and biophysical characteristics can be monitored in a high-throughput screening (HTS) format. However, it remains impractical and arguably unethical to screen samples in this way for immunological functionality in animal models. Furthermore, data for immunological functionality lag formulation design by months, making it cumbersome to relate back to formulations in real-time. It is also likely that animal testing may not accurately reflect the response in humans. For a more effective formulation screen, a human whole blood (hWB) approach can be used to assess immunological functionality. The functional activity relates directly to the human immune response to a complete formulation (adjuvant/antigen) and includes adjuvant response, antigen response, adjuvant-modulated antigen response, stability, and potentially safety. The following commentary discusses the hWB approach as a valuable new tool to de-risk manufacture, formulation design, and clinical progression

    Warthin\u27s Tumor Of The Parotid Gland

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    Phleborheography: A Correlative Study with Venography

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    The Vascular Laboratory of Henry Ford Hospital has used the Cranley-Grass Phleborheograph (PRG) as the primary noninvasive method to determine the presence or absence of deep venous thrombosis (DVT) in the lower limbs since December 1977. In order to determine its proper role and clinical reliability, we compared the diagnostic accuracy of phleborheography with contrast venography. From December 1977 through December 1978, 483 cases (963 limbs) were successfully examined by PRG. Ofthese, 111 cases (216 limbs) also had contrast venography. The PRG was confirmed as normal in 151 out of 157 (6 false negatives). There were 53 abnormal PRCs, with 35 confirmed by venography and 18 false positives. Six PRCs were considered equivocal. Sensitivity on a per limb basis was .85. The overall specificity was .86, and when equivocal examinations were excluded, it was .89. Phleborheography is safe, reliable, widely applicable, and well-tolerated. However, skilled technicians and careful interpretation are essential to its success

    Molecular dynamics simulations of nanoindentation and nanotribology

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    We present results of parallel molecular dynamics simulations of nanoindentation and nanotribology experiments. The models we have developed describe both the sample and the indenter atomistically and model the effect of the cantilevers in an atomic force microscope through the use of springs. We show that the simulations are in good qualitative agreement with experiment and help to elucidate many of the mechanisms that take place during these processes. In particular, we illustrate the role that dislocations play both in nanoindentation and also in stickā€“slip. Further to this we show how real-time visualization and computational steering have been employed in these simulations to capture the dynamical events that take place
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