25 research outputs found

    In Vitro Dissolution Tests of Plutonium and Americium Containing Contamination Originating From ZPPR Fuel Plates

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    Assessing the extent of internal dose is of concern whenever workers are exposed to airborne radionuclides or other contaminants. Internal dose determinations depend upon a reasonable estimate of the expected biological half-life of the contaminants in the respiratory tract. One issue with refractory elements is determining the dissolution rate of the element. Actinides such as plutonium (Pu) and Americium (Am) tend to be very refractory and can have biological half-lives of tens of years. In the event of an exposure, the dissolution rates of the radionuclides of interest needs to be assessed in order to assign the proper internal dose estimates. During the November 2011 incident at the Idaho National Laboratory (INL) involving a ZPPR fuel plate, air filters in a constant air monitor (CAM) and a giraffe filter apparatus captured airborne particulate matter. These filters were used in dissolution rate experiments to determine the apparent dissolution half-life of Pu and Am in simulated biological fluids. This report describes these experiments and the results. The dissolution rates were found to follow a three term exponential decay equation. Differences were noted depending upon the nature of the biological fluid simulant. Overall, greater than 95% of the Pu and 93% of the Am were in a very slow dissolving component with dissolution half-lives of over 10 years

    Anti-Angiogenic Activity of a Small Molecule STAT3 Inhibitor LLL12

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    Background: Recent data indicate the Signal Transducer and Activator of Transcription 3 (STAT3) pathway is required for VEGF production and angiogenesis in various types of cancers. STAT3 inhibitors have been shown to reduce tumor microvessel density in tumors but a direct anti-angiogenic activity has not been described. Methodology/Principal Findings: We investigated the direct action of a small molecule inhibitor of STAT3 (LLL12) in human umbilical cord vascular endothelial cells (HUVECs) in vitro, in a Matrigel model for angiogenesis in vivo, and its antitumor activity in a xenograft model of osteosarcoma. LLL12 (100 nM) significantly inhibited VEGF-stimulated STAT3 phosphorylation in HUVECs, reduced their proliferation/migration and inhibited VEGF-induced tube formation. Morphologic analysis of LLL12 treated HUVECs demonstrated marked changes in actin/tubulin distribution and bundling. In scid mice, LLL12 reduced microvessel invasion into VEGF-infused Matrigel plugs by,90 % at a dose of 5 mg/kg daily. Following a period of tumor progression (2 weeks), LLL12 completely suppressed further growth of established OS-1 osteosarcoma xenografts. Pharmacodynamic studies showed robust phosphorylated STAT3 in control tumors, whereas phospho-STAT3 was not detected in LLL12-treated OS-1 tumors. Treated tumors demonstrated decreased proliferation (Ki67 staining), and decreased microvessel density (CD34 staining), but no significant increase in apoptosis (TUNEL staining), relative to controls. Assay of angiogenic factors, using an antibody array, showed VEGF, MMP-9, Angiopoietin1/2, Tissue Factor and FGF-

    Webometrics benefitting from web mining? An investigation of methods and applications of two research fields

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    Webometrics and web mining are two fields where research is focused on quantitative analyses of the web. This literature review outlines definitions of the fields, and then focuses on their methods and applications. It also discusses the potential of closer contact and collaboration between them. A key difference between the fields is that webometrics has focused on exploratory studies, whereas web mining has been dominated by studies focusing on development of methods and algorithms. Differences in type of data can also be seen, with webometrics more focused on analyses of the structure of the web and web mining more focused on web content and usage, even though both fields have been embracing the possibilities of user generated content. It is concluded that research problems where big data is needed can benefit from collaboration between webometricians, with their tradition of exploratory studies, and web miners, with their tradition of developing methods and algorithms

    LCROSS (Lunar Crater Observation and Sensing Satellite) Observation Campaign: Strategies, Implementation, and Lessons Learned

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    Mapping Settlements in the Wildland Urban Interface: A Decision Tree Approach

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    The wildland–urban interface (WUI) is the area where human-built structures intermingle or abut wildland vegetation. Maps of the WUI are important for resource management, particularly related to wildfire mitigation, but are often based on spatially coarse data such as housing counts from census blocks. Here, three decision tree models are used to create maps of human settlements for use in delineating the WUI. The first model uses statistics derived from image objects; the second model uses data related to topography, amenities, and accessibility; and the third model uses all available data. The accuracy of the models was evaluated in terms of the percentage of actual structures that fall within the area delineated as settlements. Overall, the three decision models performed similarly, although the third decision tree model was the best. For delineating settlements, all three decision tree models represent an improvement over a null model and the Radeloff et al. (2005) WUI mapping methodology and perform similar to the Wilmer and Aplet (2005) WUI mapping methodology. The models are also more flexible than many existing models, as they allow users to trade off accuracy and the size of the delineated settlement. The strategies described here can potentially yield improved maps of the WUI over larger areas

    Childsmile: the national child oral health improvement programme in Scotland. Part 1: establishment and development

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    This paper is the first of two reviewing the Childsmile programme. It sets out to describe the development and implementation of this national oral health improvement programme for children in Scotland over its initial three-year period (January 2006 to December 2008) and into its second phase of development. It outlines the context in which the initiative was conceived, the initial development of its various components, and how monitoring and evaluation are shaping the delivery and direction of the programme
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