1,835 research outputs found

    Hull-form optimization of a 66,000 dwt bulk carrier in irregular wave condition

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    This paper deploys optimization techniques to obtain the optimum hull form of a 66,000 DWT bulk carrier in calm water and in irregular head waves at sea state 6. Parametric modification functions for the bow hull-form variation are SAC shape, section shape (U-V type, DLWL type). Multi-objective functions are applied to minimize the values of wave-making resistance in calm water and mean added resistance in waves. WAVIS version 1.3 is used to obtain wave-making resistance in calm water condition. The modified Fujii and Takahashi's formula is applied to obtain the added resistance in short waves. The added resistance in long wave is obtained from the potential-flow solver based on the 3-D panel method. And the mean added resistance in irregular head waves is obtained by linear superposition of the wave spectrum and the response function. The PSO (Particle swarm optimization) algorithm is employed for the optimization technique. The resistance and motion characteristics in calm water, in regular head waves and in irregular head waves of the two hull forms are compared. It has been shown that the optimal brings 6.8% reduction in the mean added resistance at sea state 6

    In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser

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    The remarkably high superconducting transition temperature and upper critical field of iron(Fe)-based layered superconductors, despite ferromagnetic material base, open the prospect for superconducting electronics. However, success in superconducting electronics has been limited because of difficulties in fabricating high-quality thin films. We report the growth of high-quality c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk superconductivity by using an in-situ pulsed laser deposition technique with a 248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The temperature and field dependences of the magnetization showing strong diamagnetism and transport critical current density with superior Jc-H performance are reported. These results provide necessary information for practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let

    Variation in leaf functional traits of the Korean maple (Acer pseudosieboldianum) along an elevational gradient in a montane forest in Southern Korea

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    Plant functional traits have been shown to be useful to understand how and why ecosystems and their components vary across environmental heterogeneity or gradients. This study investigated how plant functional (leaf) traits vary according to an elevation-associated environmental gradient. Environmental gradients (mean annual temperature and precipitation) were quantified, and leaf traits (leaf area, specific leaf area, leaf nitrogen, leaf phosphorus, leaf carbon, and leaf C/N ratio) of the understory woody plant species Acer pseudosieboldianum were examined across an elevational gradient ranging from 600 to 1200 m in a Baegunsan Mountain in Gwangyang-si, Jeollanam-do, South Korea. The results showed that mean annual temperature and precipitation decreased and increased along with elevation, respectively. Leaf area of the plant species decreased slightly with increasing elevation, while specific leaf area did not differ significantly. Leaf nutrients (nitrogen, phosphorus, and carbon concentrations) were higher at high elevations, but leaf C/N ratio decreased with elevation.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2015R1C1A1A01053841), (2017-0994)

    Escuelas promotoras de la salud: un programa multicompente para prevenir los riesgos conductuales en adolescentes (2014-2017)

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    DOI: 10.26439/persona2020.n023(1).4834 This article is based on the analysis of the systematization of the Health Promoting School project implemented in Lima, Peru, from 2014 to 2017 by an agreement between the International cooperation agency of South Korea and the Ministry of health in Peru. A description of the phases developed, the strategies used, and the alliances built for their implementation will be presented. For that purpose, a review of secondary sources and interviews to key players as primary sources were made. The project considered the prevention and health promotion paradigms as complementary ones.DOI: 10.26439/persona2020.n023(1).4834 Este artículo se basa en el análisis de la sistematización del Proyecto de las Escuelas Promotoras de la Salud, implementado en Lima, Perú, del 2014 al 2017, a través de un acuerdo entre la Agencia de Cooperación Internacional de Corea del Sur, y el ministerio de Salud de Perú. Se describe el desarrollo de las fases del proyecto, las estrategias que se usaron, así como las alianzas que se construyeron para la implementación del proyecto. Para el análisis se revisaron fuentes secundarias y se entrevistaron a los agentes clave, como fuentes primarias. Consideramos que los paradigmas de prevención y promoción de la salud deben ser considerados como complementarios

    Eosinophilic gastroenteritis in an 18-year-old male with prolonged nephrotic syndrome

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    Eosinophilic gastroenteritis is a rare disease characterized by prominent eosinophilic tissue infiltration of the gastrointestinal tract. Here, we report a case of eosinophilic gastroenteritis in an 18-year-old patient with prolonged nephrotic syndrome who presented with abdominal pain and peripheral hypereosinophilia. During the previous 2 years, he had visited local Emergency Department several times because of epigastric pain and nausea. He had been treated with steroid-dependent nephrotic syndrome since 3 years of age. Tests ruled out allergic and parasitic disease etiologies. Gastroduodenoscopy with biopsy revealed marked eosinophilic infiltration in the duodenum. Renal biopsy findings indicated minimal change disease spectrum without eosinophilic infiltration. The oral deflazacort dosage was increased, and the patient was discharged after abdominal pain resolved. To our knowledge, this is the first report of eosinophilic gastroenteritis in a patient with minimal change disease

    Tai Chi for Lower Urinary Tract Symptoms and Quality of Life in Elderly Patients with Benign Prostate Hypertrophy: A Randomized Controlled Trial

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    Tai chi exercise has been recommended as suitable for the improvement of health in the elderly. The purpose of this study was to investigate the effects of tai chi on lower urinary tract symptoms (LUTSs), quality of life (QoL), and sex hormone levels in patients with benign prostate hypertrophy (BPH). The elderly patients with BPH were randomized to receive tai chi or usual care. Fifty-six participants were randomized into either the tai chi group (n = 28) or the control group (n = 28). After 12 weeks of treatment, the tai chi group showed significant improvement in LUTS and QoL. There was a significant effect of tai chi on testosterone but no significant effect on insulin or glucose. No serious adverse events were observed during the study period. In conclusion, our results suggest that 12 weeks of tai chi may improve LUTS and QoL in elderly patients with BPH

    Cocoa polyphenols suppress TNF-α-induced vascular endothelial growth factor expression by inhibiting phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase kinase-1 (MEK1) activities in mouse epidermal cells

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    Cocoa polyphenols have antioxidant and anti-inflammatory effects. TNF-α is a pro-inflammatory cytokine that has a vital role in the pathogenesis of inflammatory diseases such as cancer and psoriasis. Vascular endothelial growth factor (VEGF) expression is associated with tumorigenesis, CVD, rheumatoid arthritis and psoriasis. We tested whether cocoa polyphenol extract (CPE) inhibited TNF-α-induced VEGF expression in promotion-sensitive JB6 mouse epidermal cells. CPE significantly inhibited TNF-α-induced up-regulation of VEGF via reducing TNF-α-induced activation of the nuclear transcription factors activator protein-1 (AP-1) and NF-κB, which are key regulators of VEGF expression. CPE also inhibited TNF-α-induced phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinase. CPE blocked activation of their downstream kinases, p70 kDa ribosomal protein S6 kinase and p90 kDa ribosomal protein S6 kinase. CPE suppressed phosphoinositide 3-kinase (PI3K) activity via binding PI3K directly. CPE did not affect TNF-α-induced phosphorylation of mitogen-activated protein kinase kinase-1 (MEK1) but suppressed TNF-α-induced MEK1 activity. Collectively, these results indicate that CPE reduced TNF-α-induced up-regulation of VEGF by directly inhibiting PI3K and MEK1 activities, which may contribute to its chemopreventive potentia

    Perception of precocious puberty among school-aged children in South Korea with the experience of treatment for precocious puberty: a Q methodological approach

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    Purpose This study aimed to investigate the perceptions of precocious puberty and elucidate the distinct characteristics of each type of perception related to precocious puberty among school-aged children who had undergone treatment for the condition. Methods This study applied the Q methodology to identify and classify the perceptions of precocious puberty among school-aged children who had undergone treatment for the condition. The analysis involved 34 questions from the Q sample and data from 35 individuals in the P sample, using the PC-QUANL Program for analysis. Results The perceptions of precocious puberty among school-aged children who had undergone precocious puberty treatment were classified into the following four types: "shyness - passive self-management," "resentment - suppression," "anxiety - fear," and "adaptation - acceptance." Conclusion This study investigated the experiences and perceptions of children who have undergone treatment for precocious puberty. Through the identification of four types of perceptions, we can see that there is a need to develop an intervention program for nursing that is tailored to the specific type of precocious puberty
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