760 research outputs found

    Micro-Ramp Flow Control for Oblique Shock Interactions: Comparisons of Computational and Experimental Data

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    Computational fluid dynamics was used to study the effectiveness of micro-ramp vortex generators to control oblique shock boundary layer interactions. Simulations were based on experiments previously conducted in the 15 x 15 cm supersonic wind tunnel at NASA Glenn Research Center. Four micro-ramp geometries were tested at Mach 2.0 varying the height, chord length, and spanwise spacing between micro-ramps. The overall flow field was examined. Additionally, key parameters such as boundary-layer displacement thickness, momentum thickness and incompressible shape factor were also examined. The computational results predicted the effects of the micro-ramps well, including the trends for the impact that the devices had on the shock boundary layer interaction. However, computing the shock boundary layer interaction itself proved to be problematic since the calculations predicted more pronounced adverse effects on the boundary layer due to the shock than were seen in the experiment

    Micro-Ramp Flow Control for Oblique Shock Interactions: Comparisons of Computational and Experimental Data

    Get PDF
    Computational fluid dynamics was used to study the effectiveness of micro-ramp vortex generators to control oblique shock boundary layer interactions. Simulations were based on experiments previously conducted in the 15- by 15-cm supersonic wind tunnel at the NASA Glenn Research Center. Four micro-ramp geometries were tested at Mach 2.0 varying the height, chord length, and spanwise spacing between micro-ramps. The overall flow field was examined. Additionally, key parameters such as boundary-layer displacement thickness, momentum thickness and incompressible shape factor were also examined. The computational results predicted the effects of the microramps well, including the trends for the impact that the devices had on the shock boundary layer interaction. However, computing the shock boundary layer interaction itself proved to be problematic since the calculations predicted more pronounced adverse effects on the boundary layer due to the shock than were seen in the experiment

    Review: the use of real-time fluorescence instrumentation to monitor ambient primary biological aerosol particles (PBAP)

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    Primary biological aerosol particles (PBAP) encompass many particle types that are derived from several biological kingdoms. These aerosol particles can be composed of both whole living units such as pollen, bacteria, and fungi, as well as from mechanically formed particles, such as plant debris. They constitute a significant proportion of the overall atmospheric particle load and have been linked with adverse health issues and climatic effects on the environment. Traditional methods for their analysis have focused on the direct capture of PBAP before subsequent laboratory analysis. These analysis types have generally relied on direct optical microscopy or incubation on agar plates, followed by time-consuming microbiological investigation. In an effort to address some of these deficits, real-time fluorescence monitors have come to prominence in the analysis of PBAP. These instruments offer significant advantages over traditional methods, including the measurement of concentrations, as well as the potential to simultaneously identify individual analyte particles in real-time. Due to the automated nature of these measurements, large data sets can be collected and analyzed with relative ease. This review seeks to highlight and discuss the extensive literature pertaining to the most commonly used commercially available real-time fluorescence monitors (WIBS, UV-APS and BioScout). It discusses the instruments operating principles, their limitations and advantages, and the various environments in which they have been deployed. The review provides a detailed examination of the ambient fluorescent aerosol particle concentration profiles that are obtained by these studies, along with the various strategies adopted by researchers to analyze the substantial data sets the instruments generate. Finally, a brief reflection is presented on the role that future instrumentation may provide in revolutionizing this area of atmospheric research

    Interventional Radiology and the Care of the Oncology Patient

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    Interventional Radiology (IR) is occupying an increasingly prominent role in the care of patients with cancer, with involvement from initial diagnosis, right through to minimally invasive treatment of the malignancy and its complications. Adequate diagnostic samples can be obtained under image guidance by percutaneous biopsy and needle aspiration in an accurate and minimally invasive manner. IR techniques may be used to place central venous access devices with well-established safety and efficacy. Therapeutic applications of IR in the oncology patient include local tumour treatments such as transarterial chemo-embolisation and radiofrequency ablation, as well as management of complications of malignancy such as pain, organ obstruction, and venous thrombosis

    A Fat Body-Derived IGF-like Peptide Regulates Postfeeding Growth in Drosophila

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    SummaryMembers of the insulin family of peptides have conserved roles in the regulation of growth and metabolism in a wide variety of metazoans. Here we show that Drosophila insulin-like peptide 6 (DILP6), which is structurally similar to vertebrate insulin-like growth factor (IGF), is predominantly expressed in the fat body, a functional equivalent of the vertebrate liver and adipocytes. This expression occurs during the postfeeding stage under the direct regulation of ecdysteroid. We further reveal that dilp6 mutants show growth defects during the postfeeding stage, which results in reduced adult body size through a decrease in cell number. This phenotype is rescued by fat body-specific expression of dilp6. These data indicate that DILP6 is a functional, as well as a structural, counterpart of vertebrate IGFs. Our data provide in vivo evidence for a role of ILPs in determining adult body size through the regulation of postfeeding growth

    Minimization of Radiation Exposure due to Computed Tomography in Inflammatory Bowel Disease

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    Patient awareness and concern regarding the potential health risks from ionizing radiation have peaked recently (Coakley et al., 2011) following widespread press and media coverage of the projected cancer risks from the increasing use of computed tomography (CT) (Berrington et al., 2007). The typical young and educated patient with inflammatory bowel disease (IBD) may in particular be conscious of his/her exposure to ionising radiation as a result of diagnostic imaging. Cumulative effective doses (CEDs) in patients with IBD have been reported as being high and are rising, primarily due to the more widespread and repeated use of CT (Desmond et al., 2008). Radiologists, technologists, and referring physicians have a responsibility to firstly counsel their patients accurately regarding the actual risks of ionizing radiation exposure; secondly to limit the use of those imaging modalities which involve ionising radiation to clinical situations where they are likely to change management; thirdly to ensure that a diagnostic quality imaging examination is acquired with lowest possible radiation exposure. In this paper, we synopsize available evidence related to radiation exposure and risk and we report advances in low-dose CT technology and examine the role for alternative imaging modalities such as ultrasonography or magnetic resonance imaging which avoid radiation exposure

    Supporting and preparing patients for radiotherapy: Patients’ and radiation therapists’ perspectives on their one-to-one consultations

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    OBJECTIVE: Patients are often anxious and lack knowledge of radiotherapy prior to commencing treatment. Evidence-based interventions are required to reduce patient anxiety and increase patient preparation before treatment. This study is part of a larger project examining the effectiveness of an innovative preparatory intervention "RT Prepare," to reduce patient psychological distress prior to treatment for breast cancer. This study aimed to explore patients' and RTs' perceptions about the "RT Prepare" intervention and was conducted to assist with refinement of the intervention for future implementation. METHODS: Semi-structured interviews were conducted with patients and radiation therapists (RTs) to elicit their perspectives on the "RT Prepare" intervention. Thematic analysis was used to analyse the data. RESULTS: Telephone interviews were conducted with 21 patients who had received the intervention and 15 RTs who had delivered the intervention. Patients and RTs described the intervention positively and highlighted that it was beneficial for preparing patients for treatment planning and treatment. The overarching themes were communication skills; preparation; information provision and dedicated space and time. CONCLUSION: RT Prepare was well received by patients and RTs. Practice implications Based on the results of this study and our quantitative findings, implementation of the intervention would be beneficial for both patients and RTs

    Esophageal intramural pseudodiverticulosis characterized by barium esophagography: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Esophageal intramural pseudodiverticulosis is a rare condition characterized by the dilatation of the submucosal glands.</p> <p>Case presentation</p> <p>We present a case of esophageal intramural pseudodiverticulosis in a 72-year-old Caucasian man who presented with dysphagia and with a background history of alcohol abuse. An upper gastrointestinal endoscopy of our patient showed an esophageal stricture with abnormal mucosal appearances, but no malignant cells were seen at biopsy. Appearances on a barium esophagram were pathognomonic for esophageal intramural pseudodiverticulosis.</p> <p>Conclusion</p> <p>We demonstrate the enduring usefulness of barium esophagography in the characterization of abnormal mucosal appearances at endoscopy.</p

    New resources for the Drosophila 4th chromosome : FRT101F enabled mitotic clones and Bloom syndrome helicase enabled meiotic recombination

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    Genes on the long arm of the Drosophila melanogaster 4th chromosome are difficult to study because the chromosome lacks mitotic and meiotic recombination. Without recombination numerous standard methods of genetic analysis are impossible. Here, we report new resources for the 4th. For mitotic recombination, we generated a chromosome with an FRT very near the centromere in 101F and a derivative that carries FRT101F with a distal ubiquitously expressed GAL80 transgene. This pair of chromosomes enables both unmarked and MARCM clones. For meiotic recombination, we demonstrate that a Bloom syndrome helicase and recombination defective double mutant genotype can create recombinant 4th chromosomes via female meiosis. All strains will be available to the community via the Bloomington Drosophila Stock Center. Additional resources for studies of the 4th are in preparation and will also be made available. The goal of the 4th Chromosome Resource Project is to accelerate the genetic analysis of protein-coding genes on the 4th, including the 44 genes with no demonstrated function. Studies of these previously inaccessible but largely conserved genes will close longstanding gaps in our knowledge of metazoan development and physiology.Peer reviewe

    Management Factors Associated with Operation-Level Prevalence of Antibodies to Cache Valley Virus and Other Bunyamwera Serogroup Viruses in Sheep in the United States

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    A cross-sectional study was performed to identify operation-level risk factors associated with prevalence of antibody to Bunyamwera (BUN) serogroup viruses in sheep in the United States. Sera were obtained from 5150 sheep in 270 operations located in 22 states (three in the west, nine central states, and 10 in the east) and tested at a dilution of 1:20 by a plaque reduction neutralization test (PRNT) using Cache Valley virus (CVV). Antibodies that neutralized CVV were identified in 1455 (28%) sheep. Animal-level seroprevalence was higher in the east (49%) than the central (17%) and western (10%) states. A convenient subset (n = 509) of sera with antibodies that neutralized CVV was titrated and further analyzed by PRNT using all six BUN serogroup viruses that occur in the United States: CVV, Lokern virus (LOKV), Main Drain virus (MDV), Northway virus (NORV), Potosi virus (POTV), and Tensaw virus (TENV). Antibodies to CVV and LOKV were identified in sheep in all three geographic regions; MDV and POTV activity was detected in the central and eastern states, NORV activity was restricted to the west, and antibodies to TENV were not detected in any sheep. Several management factors were significantly associated with the presence of antibodies to BUN serogroup viruses. For instance, sheep housed during the lambing season inside structures that contained four walls and a roof and a door closed most of the time were more likely to be seropositive than other sheep. In contrast, herded/open-range sheep were less likely to be seropositive than their counterparts. These data can be used by producers to implement strategies to reduce the likelihood of BUN serogroup virus infection and improve the health and management practices of sheep
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