2,804 research outputs found

    An Efficient ISAR Imaging Method for Multiple Targets

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    This paper proposes an efficient method to obtain TSAR images of multiple targets flying in formation. The proposed method improves the coarse alignment and segmentation of the existing method. The improved coarse alignment method models the flight trajectory using a combination of a polynomial and Gaussian basis functions, and the optimum parameter of the trajectory is found using particle swarm optimization. In the improved segmentation, the binary image of the bulk TSAR image that contains all targets is constructed using a two-dimensional constant false alarm detector, then the image closing method is applied to the binary image. Finally, the connected set of binary pixels is used to segment each target from the bulk image. Simulations using three targets composed of point scattering centers and the measured data of the Boeing747 aircraft prove the effectiveness of the proposed method to segment three targets flying in formation.X113Ysciescopu

    Echo Path Transfer Function Estimation for Spectral Subtraction-based Acoustic Echo Suppression

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    In this study, we propose a novel technique for spectral subtraction (SS)-based acoustic echo suppression (AES). Conventional AES methods based on SS apply fixed weights to the estimated echo path transfer function (EPTF) at the current signal segment and to the EPTF estimated until the previous time interval. We propose a new EPTF estimation approach that adaptively updates the weight parameters in response to abrupt changes in the acoustic environment. From the experiments, we conclude that the developed techniques can be successfully used for the SS-based AES systems

    What Questions do People Ask on a Human Papillomavirus Website? A Comparative Analysis of Public and Private Questions

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    Objective: In 2004, we launched the question and answer (Q&A) section on a human papillomavirus (HPV) website (www.hpvkorea.org) that provides ample and regularly updated information about HPV. The purpose of this study is to collect data pertaining to questions posed on this website about HPV and its related diseases and analyze the type of questions and frequency before and after introduction of HPV vaccine in Korea. Using these results, we intend to determine the clinical and practical implications for doctors treating HPV and for HPV website providers

    Pattern of distant recurrence according to the molecular subtypes in Korean women with breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Distant recurrence is one of the most important risk factors in overall survival, and distant recurrence is related to a complex biologic interaction of seed and soil factors. The aim of the study was to investigate the association between the molecular subtypes and patterns of distant recurrence in patients with breast cancer.</p> <p>Methods</p> <p>In an investigation of 313 women with breast cancer who underwent surgery from 1994 and 2000, the expressions of estrogen and progestrone receptor (ER/PR), and human epithelial receptor-2 (HER2) were evaluated. The subtypes were defined as luminal-A, luminal-HER2, HER2-enriched, and triple negative breast cancer (TNBC) according to ER, PR, and HER2 status.</p> <p>Results</p> <p>Bone was the most common site of distant recurrence. The incidence of first distant recurrence site was significantly different among the subtypes. Brain metastasis was more frequent in the luminal-HER2 and TNBC subtypes. In subgroup analysis, overall survival in patients with distant recurrence after 24 months after surgery was significantly different among the subtypes.</p> <p>Conclusions</p> <p>Organ-specific metastasis may depend on the molecular subtype of breast cancer. Tailored strategies against distant metastasis concerning the molecular subtypes in breast cancer may be considered.</p

    Effects of Chung-Pae Inhalation Therapy on a Mouse Model of Chronic Obstructive Pulmonary Disease

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    Chung-pae (CP) inhalation therapy is a method frequently used in Korea to treat lung disease, especially chronic obstructive pulmonary disease (COPD). This study investigated the effects of CP inhalation on a COPD animal model. C57BL/6 mice received porcine pancreatic elastase (PPE) and lipopolysaccharide (LPS) alternately three times for 3 weeks to induce COPD. Then, CP (5 or 20 mg/kg) was administered every 2 h after the final LPS administration. The effect of CP was evaluated by bronchoalveolar lavage (BAL) fluid analysis, histological analysis of lung tissue, and reverse transcription polymerase chain reaction analysis of mRNA of interleukin- (IL-) 1β, tumor necrosis factor- (TNF-) α, IL-6, and tumor growth factor- (TGF-) β. Intratracheal CP administration reduced the number of leukocytes and neutrophils in BAL fluid, inhibited the histological appearance of lung damage, and decreased the mRNA levels of the proinflammatory cytokines IL-1β, TNF-α, IL-6, and TGF-β. Intratracheal CP administration effectively decreased the chronic inflammation and pathological changes in a PPE- and LPS-induced COPD mouse model. Therefore, we suggest that CP is a promising strategy for COPD

    Portulaca oleracea Ameliorates Diabetic Vascular Inflammation and Endothelial Dysfunction in db/db Mice

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    Type 2 diabetes is associated with significantly accelerated rates of micro- and macrovascular complications such as diabetic vascular inflammation and endothelial dysfunction. In the present study, we investigated the protective effect of the aqueous extract of Portulaca oleracea L. (AP), an edible plant used as a folk medicine, on diabetic vascular complications. The db/db mice were treated with AP (300 mg/kg/day, p.o.) for 10 weeks, and AP treatment markedly lowered blood glucose, plasma triglyceride, plasma level of LDL-cholesterol, and systolic blood pressure in diabetic db/db mice. Furthermore, AP significantly increased plasma level of HDL-cholesterol and insulin level. The impairment of ACh- and SNP-induced vascular relaxation of aortic rings were ameliorated by AP treatment in diabetic db/db mice. This study also showed that overexpression of VCAM-1, ICAM-1, E-selectin, MMP-2, and ET-1 were observed in aortic tissues of untreated db/db mice, which were significantly suppressed by treatment with AP. We also found that the insulin immunoreactivity of the pancreatic islets remarkably increased in AP treated db/db mice compared with untreated db/db mice. Taken together, AP suppresses hyperglycemia and diabetic vascular inflammation, and prevents the development of diabetic endothelial dysfunction for the development of diabetes and its vascular complications
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