127 research outputs found

    Aerodynamic preliminary analysis system 2. Part 2: User's manual

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    An aerodynamic analysis system based on potential theory at subsonic and/or supersonic speeds and impact type finite element solutions at hypersonic conditions is described. Three dimensional configurations have multiple nonplanar surfaces of arbitrary planforms and bodies of noncircular contour may be analyzed. Static, rotary, and control longitudinal and lateral-directional characteristics may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis. Computation times on an IBM 3081 are typically less than one minute of CPU/Mach number at subsonic, supersonic, or hypersonic speeds. This is a user manual for the computer programming

    Aerodynamic preliminary analysis system. Part 2: User's manual and program description

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    A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple nonplanar surfaces of arbitrary planform and open or closed slender bodies or noncircular contour are analyzed. Longitudinal and lateral-directional static and rotary derivative solutions are generated. The analysis is implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies

    Antimicrobial properties of nanostructured surfaces - demonstrating the need for a standard testing methodology

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    Bioinspired nanostructured materials that exhibit antimicrobial properties are being synthesized and tested at increasing rates for use in healthcare, manufacturing processes, and diagnostics. Although progress has been made in improving and understanding their bactericidal activity, arguably, the biggest problem currently in the field is the lack of a standard testing methodology that allows for optimal characterization and better comparison of emerging nanostructures. Here, we examine two forms of nanostructured silicon that vary in their ability to kill certain bacterial species due to different physical mechanisms and derive guidelines for the comparative testing. We perform a comprehensive evaluation of methodologies used extensively in the field (e.g., colony counting and live dead analysis) and the novel application of high-throughput flow cytometry. The data reveal how the techniques are complementary but not always directly equivalent or correlative. Therefore, comparison of results obtained using different methodologies on different materials can be grossly misleading. We report significant variations in bactericidal efficiencies depending on experimental environments (medium type, etc.) and methodologies employed. In addition, we demonstrate how cytometry is yet another powerful complementary tool that can aid the mechanistic understanding of antimicrobial activities of rough surfaces. Besides standardization for comparison, ultimately, evaluation methods need to consider anticipated applications. Then and only then can the true potential (or limitation) of a novel material be determined for its suitability for advancement in a particular field of use

    Isolasi dan Karakterisasi Mikroba Termofilik Penghasil Xilanase dari Lumpur Panas Lapindo sebagai Alternatif Pengganti Klorin pada Industri Kertas

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    This study aimed to isolate xylanase producing microbe from hot mud in Lapindo area disaster. This microbes were supposed to be extremophillic bacterium because of extreme condition of hot mud. This study comrised of sampling hot mud disaster, isolation and characterization of thermophillic isolates, and characterization of thermophillic xylanase. The result showed that 14 xylanolitic isolates were obtained and one isolate (C211) had the best xylanase activity. This enzyme had optimum activity at 50°C and pH 7.0, and showed the hydrolytic activity of 2.60 unit/mL/min

    Prevalence of vaginitis, syphilis and HIV infection in women in the Orange Free State

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    Objective. To determine the prevalence of vaginitis, syphilis and HIV infection in women in the Orange Free State.Method. By cluster sampling, 120 rural (farm) and 120 urban (local authority) clusters, each containing 4 women, were selected. Women aged 18 - 49 years who were included in the study had a cervical smear taken for cytological evaluation and blood specimens drawn for syphilis and HIV testing; they were questioned on their knowledge of AIDS.Results. Trichomonas vaginalis vaginitis was present in 27,4% of the rural women and 29,6% of the urban women, Gardnerella vaginalis in 7,2% and 8,4% and Candida spp. in 2,6% and 6,7% respectively. Syphilis serology was positive in 12% of rural and 16% of urban women. HIV was present in 0,4% of rural and 1,5% of urban women. Ninety per cent of urban women and 74% of rural women knew AIDS was a sexually transmitted disease.Conclusions. The prevalences of trichomonas vaginitis and syphilis were unusually high, while HIV positivity was similar to that in other reports in South Africa

    Limited role of culture conversion for decision-making in individual patient care and for advancing novel regimens to confirmatory clinical trials

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    Supported by the European and Developing Country Clinical Trials Partnership (grant IP.2007.32011.011) and the Global Alliance for TB Drug Development, with support from the Bill & Melinda Gates Foundation, US Agency for International Development, UK Department for International Development, Directorate-General for International Cooperation of the Netherlands, Irish Aid and Australian Department of Foreign Affairs and Trade.Background Despite recent increased clinical trials activity, no regimen has proved able to replace the standard 6-month regimen for drug-sensitive tuberculosis. Understanding the relationship between microbiological markers measured during treatment and long-term clinical outcomes is critical to evaluate their usefulness for decision-making for both individual patient care and for advancing novel regimens into time-consuming and expensive pivotal phase III trials. Methods Using data from the randomized controlled phase III trial REMoxTB, we evaluated sputum-based markers of speed of clearance of bacilli: time to smear negative status; time to culture negative status on LJ or in MGIT; daily rate of change of log10(TTP) to day 56; and smear or culture results at weeks 6, 8 or 12; as individual- and trial-level surrogate endpoints for long-term clinical outcome. Results Time to culture negative status on LJ or in MGIT, time to smear negative status and daily rate of change in log10(TTP) were each independent predictors of clinical outcome, adjusted for treatment (p <0.001). However, discrimination between low and high risk patients, as measured by the c-statistic, was modest and not much higher than the reference model adjusted for BMI, history of smoking, HIV status, cavitation, gender and MGIT TTP. Conclusions Culture conversion during treatment for tuberculosis, however measured, has only a limited role in decision-making for advancing regimens into phase III trials or in predicting the outcome of treatment for individual patients. REMoxTB ClinicalTrials.gov number: NCT00864383.Publisher PDFPeer reviewe

    Limited role of culture conversion for decision-making in individual patient care and for advancing novel regimens to confirmatory clinical trials

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    Supported by the European and Developing Country Clinical Trials Partnership (grant IP.2007.32011.011) and the Global Alliance for TB Drug Development, with support from the Bill & Melinda Gates Foundation, US Agency for International Development, UK Department for International Development, Directorate-General for International Cooperation of the Netherlands, Irish Aid and Australian Department of Foreign Affairs and Trade.Background Despite recent increased clinical trials activity, no regimen has proved able to replace the standard 6-month regimen for drug-sensitive tuberculosis. Understanding the relationship between microbiological markers measured during treatment and long-term clinical outcomes is critical to evaluate their usefulness for decision-making for both individual patient care and for advancing novel regimens into time-consuming and expensive pivotal phase III trials. Methods Using data from the randomized controlled phase III trial REMoxTB, we evaluated sputum-based markers of speed of clearance of bacilli: time to smear negative status; time to culture negative status on LJ or in MGIT; daily rate of change of log10(TTP) to day 56; and smear or culture results at weeks 6, 8 or 12; as individual- and trial-level surrogate endpoints for long-term clinical outcome. Results Time to culture negative status on LJ or in MGIT, time to smear negative status and daily rate of change in log10(TTP) were each independent predictors of clinical outcome, adjusted for treatment (p <0.001). However, discrimination between low and high risk patients, as measured by the c-statistic, was modest and not much higher than the reference model adjusted for BMI, history of smoking, HIV status, cavitation, gender and MGIT TTP. Conclusions Culture conversion during treatment for tuberculosis, however measured, has only a limited role in decision-making for advancing regimens into phase III trials or in predicting the outcome of treatment for individual patients. REMoxTB ClinicalTrials.gov number: NCT00864383.Publisher PDFPeer reviewe

    Reddening law and interstellar dust properties along Magellanic sight-lines

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    This study establishes that SMC, LMC and Milky Way extinction curves obey the same extinction law which depends on the 2200A bump size and one parameter, and generalizes the Cardelli, Clayton and Mathis (1989) relationship. This suggests that extinction in all three galaxies is of the same nature. The role of linear reddening laws over all the visible/UV wavelength range, particularly important in the SMC but also present in the LMC and in the Milky Way, is also highlighted and discussed.Comment: accepted for publication in Astrophysics and Space Science. 16 pages, 12 figures. Some figures are colour plot

    Learning through assessment

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    This book aims to contribute to the discourse of learning through assessment within a self-directed learning environment. It adds to the scholarship of assessment and self-directed learning within a face-to-face and online learning environment. As part of the NWU Self-Directed Learning Book Series, this book is devoted to scholarship in the field of self-directed learning, focusing on ongoing and envisaged assessment practices for self-directed learning through which learning within the 21st century can take place. This book acknowledges and emphasises the role of assessment as a pedagogical tool to foster self-directed learning during face-to-face and online learning situations. The way in which higher education conceptualises teaching, learning and assessment has been inevitably changed due to the COVID- 19 pandemic, and now more than ever we need learners to be self-directed in their learning. Assessment plays a key role in learning and, therefore, we have to identify innovative ways in which learning can be assessed, and which are likely to become the new norm even after the pandemic has been brought under control. The goal of this book, consisting of original research, is to assist with the paradigm shift regarding the purpose of assessment, as well as providing new ideas on assessment strategies, methods and tools appropriate to foster self-directed learning in all modes of delivery
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