1,590 research outputs found

    Recent development of inorganic nanoparticles for biomedical imaging

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    Inorganic nanoparticle-based biomedical imaging probes have been studied extensively as a potential alternative to conventional molecular imaging probes. Not only can they provide better imaging performance but they can also offer greater versatility of multimodal, stimuli-responsive, and targeted imaging. However, inorganic nanoparticle-based probes are still far from practical use in clinics due to safety concerns and less-optimized efficiency. In this context, it would be valuable to look over the underlying issues. This outlook highlights the recent advances in the development of inorganic nanoparticle-based probes for MRI, CT, and anti-Stokes shift-based optical imaging. Various issues and possibilities regarding the construction of imaging probes are discussed, and future research directions are suggested.

    A Study on Urban Regeneration Policy Change in Korea

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    After the physical redevelopment and reconstruction in the late 1970s, the paradigm on urban regeneration in Korea shifted from maintenance to restoration and sustainability. This study highlighted that those changes occurred rapidly and not gradually over a short period of time. This study researched diachronic changes on urban regeneration policies after the 1970s in Korea using an analysing model that compensated for the theoretical limits of Hogwood and Peters. The limitations of former policies and internal and external socio-economic factors are shown to have affected dynamic policy changes. This study’s academic significance is that it suggests policy implications for cities that have similar urban growth processes to Korea

    Design principles for transforming making programs into online settings at public libraries

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    Purpose This paper aims to investigate design principles for transforming existing making communities of practice within public libraries into online knowledge-building communities to support youths, families with young children and adult members’ making and tinkering during COVID-19. Design/methodology/approach Building upon C4P and connected learning framework, the authors analyze existing literature and practitioner reports on informal learning projects related to making and STEM learning, family learning and online learning as well as emergent cases of innovative approaches in response to COVID-19 from public libraries, informal learning institutions and community groups. Findings The authors suggest 11 design principles around five areas: program design, facilitation, tools and materials, process documentation and sharing and feedback. Originality/value This work contributes to the information and learning sciences concerned with community engagement and knowledge creation by suggesting a design model to transform and sustain existing making communities of practice within public libraries into online knowledge-building communities during COVID-19

    The Feasibility of Multidimensional CFD Applied to Calandria System in the Moderator of CANDU-6 PHWR Using Commercial and Open-Source Codes

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    The moderator system of CANDU, a prototype of PHWR (pressurized heavy-water reactor), has been modeled in multidimension for the computation based on CFD (computational fluid dynamics) technique. Three CFD codes are tested in modeled hydrothermal systems of heavy-water reactors. Commercial codes, COMSOL Multiphysics and ANSYS-CFX with OpenFOAM, an open-source code, are introduced for the various simplified and practical problems. All the implemented computational codes are tested for a benchmark problem of STERN laboratory experiment with a precise modeling of tubes, compared with each other as well as the measured data and a porous model based on the experimental correlation of pressure drop. Also the effect of turbulence model is discussed for these low Reynolds number flows. As a result, they are shown to be successful for the analysis of three-dimensional numerical models related to the calandria system of CANDU reactors

    Reverse Doppler Effect of Sound

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    We report observation of reverse Doppler effect in a double negative acoustic metamaterial. The metamaterial exhibited negative phase velocity and positive group velocity. The dispersion relation is such that the wavelength corresponding to higher frequency is longer. We observed that the frequency was down-shifted for the approaching source, and up-shifted when the source receded

    Prevalence and Management of Diabetes in Korean Adults: Korea National Health and Nutrition Examination Surveys 1998–2005

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    OBJECTIVE: This research investigated recent changes in the prevalence and management status of diabetes among Korean adults. RESEARCH DESIGN AND METHODS: The Korea National Health and Nutrition Examination Survey (KNHANES), a nationwide survey examining the general health and nutrition status of the Korean people, was conducted in 1998, 2001, and 2005. Using the first (1998; n = 5,645), second (2001; n = 4,154), and third (2005; n = 4,628) KNHANES datasets, in the present study, we estimated the prevalence of diabetes among Korean adults (aged >or=30 years), the proportions of known cases of diabetes, and the proportions of well-controlled cases of diabetes, as defined by either the American Diabetes Association (A1C <7%) or the International Diabetes Federation guidelines (A1C <6.5%). RESULTS: In 2005, the prevalence of diabetes was estimated to be 9.1% (approximately 2.58 million people: 10.2% of men and 7.9% of women), including 6.2% with known diabetes and 2.9% with newly diagnosed diabetes. The prevalence of impaired fasting glucose was 17.4% (approximately 4.94 million people). The proportion of known cases of diabetes drastically increased from 23.2% in 1998 to 41.2% in 2001 and 68.0% in 2005 (P < 0.0001). Among known diabetic patients in 2005, 43.5 and 22.9% had A1C levels <7.0 and <6.5%, respectively. CONCLUSIONS: The overall prevalence of diabetes in Korea has not changed significantly between 1998 and 2005. Physician diagnosis and treatment rates of diabetes have significantly improved during this period, but glycemic control was still poorer than that in other developed countriesope

    VALIDATION OF OPTIMALLY DESIGNED STATOR-PROPELLER SYSTEM BY EFD AND CFD

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    The development of energy-saving devices to lower the energy efficiency design index (EEDI) of ships has been actively researched worldwide. One such device is an asymmetric pre-swirl stator, which helps to improve the propulsion efficiency by recovering the rotational energy generated during propeller rotation. Determining the pitch angle is the most important factor in the design of an efficient asymmetric pre-swirl stator. To optimize the pitch angle of an asymmetric pre-swirl stator, this study deals with potential-flow, computational fluid dynamics, and model tests. The model delivered power at a design speed of 24 kt was compared by changing the pitch angle by ±2° with respect to the reference angle designed using a potential-flow program. The commercial code Star-CCM+ was used for the numerical analysis, and the model was also tested in a towing tank at Pusan National University. This study proposes an effective method for determining and verifying the optimal pitch angle of an asymmetric pre-swirl stator
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