6,916 research outputs found

    Value of using liver FDG uptake as background activity in standardizing FDG PET/CT studies

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    Thesis (M.A.)--Boston UniversityThe standardized uptake value (SUV) is increasingly being used for diagnosis, staging, and monitoring disease in clinical oncology. Comparing tumor SUV to background SUV is an attractive way to minimize variability and ensure the quality of scans across different institutions. The liver has been identified as a potential source for background normalization, however no studies have compared the liver to other background sites for a variety of cancers. The purpose of this study was to evaluate the use of liver uptake for the standardization of FDG PET/CT imaging. Scans from 145 patients were prospectively reviewed under the supervision of a radiologist with board certification in nuclear medicine (R.M.S. , 3 years of experience). Liver SUV values were correlated to mediastinum SUV values in lung and breast cancer patients, and internal jugular vein (IJV) SUV values in head and neck cancer patients. The independent t-test was used to determine if there was a statistically significant affect of the amount of incubation time or use of intravenous contrast on the SUV. For the lung and breast cancer patients, a strong correlation was observed between the mediastinum SUVmean and liver SUVmean (r = 0.89), whereas for the head and neck cancer patients, a weaker correlation was observed between the IJV SUVmean and the liver SUVmean (r = 0.69). Neither the amount of incubation time nor the use of IV contrast demonstrated a significant affect on the SUV. We conclude that liver SUVmean may be used to standardize FOG PET/CT studies in cancers of the lung, breast and head and neck. However, additional studies in other cancers as well as the affects of age, gender, benign disease and use of chemotherapy are still desired before widespread adoption of this standard

    Student wellbeing through teacher wellbeing: A Study with law teachers in the UK and Australia

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    Research confirms law students and lawyers in the US, Australia and more recently in the UK are prone to symptoms related to stress and anxiety disproportionately to other professions. In response, the legal profession and legal academy in Australia and the UK have created Wellness Networks to encourage and facilitate research and disseminate ideas and strategies that might help law students and lawyers to thrive. This project builds on that research through a series of surveys of law teachers in the UK and Australia on the presumption that law teachers are in a strong position to influence their students not only about legal matters, but on developing attitudes and practices that will help them to survive and thrive as lawyers. The comparative analysis reveals several differences, but also many similarities with law teachers in both countries reporting negative effects from neoliberal pressures on legal education programs that impact their wellbeing, performance as teachers and ability to adequately respond to student concerns

    Partial ownership arrangements in the Japanese automobile industry; 1990-2000

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    The end of the 1990’s saw a number of foreign automobile manufacturers become the largest shareholders in several Japanese automobile manufacturers. It seems logical to conclude that a firm only enters into a partial ownership arrangement (POA) if it is profit maximizing. However, research to date has treated POAs as if exogenous to the model. This paper develops a model that assumes POAs are determined endogenously. Data for the Japanese automobile industry are then used to investigate the factors that determine whether a firm enters into a POA, and the effects a POA has on the price-cost margin. The findings of this paper suggest that while both foreign and domestic firms take an interest in product mix when exploring POAs in the Japanese market, they have differing profit incentives. Furthermore, the level of ownership has a positive effect on POAs.partial ownership arrangements, price-cost margin, technology transfers

    Importer Loyalty in International Wheat Markets

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    International Relations/Trade,

    Deep dielectric charging of regolith within the Moon\u27s permanently shadowed regions

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    Abstract Energetic charged particles, such as galactic cosmic rays (GCRs) and solar energetic particles (SEPs), can penetrate deep within the lunar surface, resulting in deep dielectric charging. This charging process depends on the GCR and SEP currents, as well as on the regolith\u27s electrical conductivity and permittivity. In permanently shadowed regions (PSRs) near the lunar poles, the discharging timescales are on the order of a lunation (∼20 days). We present the first predictions for deep dielectric charging of lunar regolith. To estimate the resulting subsurface electric fields, we develop a data-driven, one-dimensional, time-dependent model. For model inputs, we use GCR data from the Cosmic Ray Telescope for the Effects of Radiation on board the Lunar Reconnaissance Orbiter and SEP data from the Electron, Proton, and Alpha Monitor on the Advanced Composition Explorer. We find that during the recent solar minimum, GCRs create persistent electric fields up to ∼700 V/m. We also find that large SEP events create transient but strong electric fields (≥106 V/m) that may induce dielectric breakdown. Such breakdown would likely result in significant modifications to the physical and chemical properties of the lunar regolith within PSRs. Key Points Energetic charged particles deep dielectrically charge the lunar regolithWe model the resulting subsurface electric fieldsThe electric fields may be great enough to induce dielectric breakdown

    Understanding radionuclide migration from the D1225 Shaft, Dounreay, Caithness, UK

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    A 65 m vertical shaft was sunk at Dounreay in the 1950s to build a tunnel for the offshore discharge of radioactive effluent from the various nuclear facilities then under construction. In 1959, the Shaft was licensed as a disposal facility for radioactive wastes and was routinely used for the disposal of ILW until 1970. Despite the operation of a hydraulic containment scheme, some radioactivity is known to have leaked into the surrounding rocks. Detailed logging, together with mineralogical and radiochemical analysis of drillcore has revealed four distinct bedding-parallel zones of contamination. The data show that Sr-90 dominates the bulk beta/gamma contamination signal, whereas Cs-137 and Pu-248/249 are found only to be weakly mobile, leading to very low activities and distinct clustering around the Shaft. The data also suggest that all uranium seen in the geosphere is natural in origin. At the smaller scale, contamination adjacent to fracture surfaces is present within a zone of enhanced porosity created by the dissolution of carbonate cements from the Caithness flagstones during long-term rockwater interactions. Quantitative modelling of radionuclide migration, using the multiphysics computer code QPAC shows the importance of different sorption mechanisms and different mineralogical substrates in the Caithnesss flagstones in controlling radionuclide migration

    The Geographic Distribution of US Executions

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    We review statistical patterns of the geographic distribution of US executions, compare them to homicides, and demonstrate extremely high degrees of concentration of executions in the modern period compared to previous historical periods. We further show that this unprecedented level of concentration has been increasing over the past 20 years. We demonstrate that it is virtually uncorrelated with factors related to homicides. Finally, we show that it corresponds to a statistical distribution associated with “self-reinforcing” processes: a power-law or exponential distribution. These findings stand whether we look at individual counties within death-penalty states, across the 50 states of the United States, or look at the international distribution of executions across countries in recent years. The substantive conclusion from the statistical patterns observed is that these cannot be explained merely by random variation around some general average. Rather, localities start down a path, then are reinforced in their pathways. There appears to be little to no logic about why certain counties are the high-use counties, whereas the vast majority have never executed a single individual in 40 years of experience with the modern death penalty, often in spite of thousands of homicides. Our research indicates that a main determinant of whether an individual will be executed is not the crime they commit, but the jurisdiction’s experience with executing others. This is not acceptable—legally, morally, or constitutionally

    The effect of lipoprotein-associated phospholipase A2 deficiency on pulmonary allergic responses in Aspergillus fumigatus sensitized mice.

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    BackgroundLipoprotein-associated phospholipase A2 (Lp-PLA2)/platelet-activating factor acetylhydrolase (PAF-AH) has been implicated in the pathogenesis of cardiovascular disease. A therapeutic targeting of this enzyme was challenged by the concern that increased circulating platelet activating factor (PAF) may predispose to or increase the severity of the allergic airway response. The aim of this study was to investigate whether Lp-PLA2 gene deficiency increases the risk of PAF and IgE-mediated inflammatory responses in vitro and in vivo using mouse models.MethodsLp-PLA2-/- mice were generated and back crossed to the C57BL/6 background. PAF-AH activity was measured using a hydrolysis assay in serum and bronchoalveolar lavage (BAL) samples obtained from mice. Aspergillus fumigatus (Af)-specific serum was prepared for passive allergic sensitization of mice in vivo and mast cells in vitro. β- hexosaminidase release was studied in bone marrow derived mast cells sensitized with Af-specific serum or DNP-IgE and challenged with Af or DNP, respectively. Mice were treated with lipopolysaccharide (LPS) and PAF intratracheally and studied 24 hours later. Mice were sensitized either passively or actively against Af and were studied 48 hours after a single intranasal Af challenge. Airway responsiveness to methacholine, inflammatory cell influx in the lung tissue and BAL, immunoglobulin (ELISA) and cytokine (Luminex) profiles were compared between the wild type (WT) and Lp-PLA2-/- mice.ResultsPAF-AH activity was reduced but not completely abolished in Lp-PLA2-/- serum or by in vitro treatment of serum samples with a high saturating concentration of the selective Lp-PLA2 inhibitor, SB-435495. PAF inhalation significantly enhanced airway inflammation of LPS treated WT and Lp-PLA2-/- mice to a similar extent. Sensitized WT and Lp-PLA2-/- bone-marrow derived mast cells released β-hexosaminidase following stimulation by allergen or IgE crosslinking to equivalent levels. Wild type and Lp-PLA2-/- mice responded to passive or active allergic sensitization by significant IgE production, airway inflammation and hyperresponsiveness after Af challenge. BAL cell influx was not different between these strains while IL-4, IL-5, IL-6 and eotaxin release was attenuated in Lp-PLA2-/- mice. There were no differences in the amount of total IgE levels in the Af sensitized WT and Lp-PLA2-/- mice.ConclusionsWe conclude that Lp-PLA2 deficiency in C57BL/6 mice did not result in a heightened airway inflammation or hyperresponsiveness after PAF/LPS treatment or passive or active allergic sensitization and challenge
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