86 research outputs found

    WCDMA Downlink Capacity Analysis based on Deterministic Ray-Tracing Channel Model

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    In this paper the analysis for WCDMA downlink capacity is presented for a real service environment at Yeouido, Seoul, Korea which is considered as a typical high rise building environment. Ray-tracing technique is used to predict site-specific sector averaged pathlosses not only from the desired node B but also from undesired node Bs to scattered receiver locations in a given cell. Total required power of node B is estimated, which limits system capacity depending on the combination of service types, macro diversity and orthogonal factor

    Approximation of most penetrating particle size for fibrous filters considering Cunningham slip correction factor

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    In the estimation of the aerosol single fiber efficiency using fibrous filters, there is a size range, where the particles penetrate most effectively through the fibrous collectors, and corresponding minimum single fiber efficiency. For small particles in which the diffusion mechanism is dominant, the Cunningham slip correction factor (Cc) affects the single fiber efficiency and the most penetrating particle size (MPPS). Therefore, for accurate estimation, Cc is essential to be considered. However, many previous studies have neglected this factor because of its complexity and the associated difficulty in deriving the appropriate parameterization particularly for the MPPS. In this study, the expression for the MPPS, and the corresponding expression for the minimum single fiber efficiency are analytically derived, and the effects of Cc are determined. In order to accommodate the slip factor for all particle-size ranges, Cc is simplified and modified. Overall, the obtained analytical expression for the MPPS is in a good agreement with the exact solution

    A Case of Papillary Thyroid Cancer Recurring as an Esophageal Submucosal Tumor

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    A 75-year-old woman who underwent a total thyroidectomy for papillary thyroid cancer 7 years previously presented with a palpable neck mass. Computed tomography (CT) showed two metastatic masses on the thyroid bed and another mass that looked benign originating from the esophageal wall. Endoscopic ultrasonography (EUS) showed a hypoechoic mass in the esophageal wall that looked similar to a gastrointestinal stromal tumor. The mass on the esophagus had intense fluorodeoxyglucose (FDG) uptake in positron emission tomography-computed tomography (PET-CT), which suggested the possibility of malignancy. Subsequently, after surgery, the mass in the esophagus was confirmed as a metastasis from the thyroid papillary carcinoma. Here we report this unusual case of papillary thyroid cancer that recurred as an esophageal submucosal tumor

    Case report: Fatal neonatal sepsis associated with Escherichia fergusonii infection in a common bottlenose dolphin (Tursiops truncatus)

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    A 25-day-old male common bottlenose dolphin (Tursiops truncatus) died suddenly while swimming at a dolphinarium. The gross examination revealed ulceration on the dorsal and pectoral fins and rostrum. Severe congestion, hemorrhage, and edema were observed in the gastrointestinal tract, liver, mesenteric lymph nodes, lungs, and kidneys. Fibrinosuppurative arthritis of the atlantooccipital joint and extension of fibrin into the spinal canal caused compression of the spinal cord. Histopathological examination revealed tracheitis, fibrinosuppurative bronchopneumonia and enteritis. In the central nervous system, meningeal vessel congestion in the brain, and intraparenchymal hemorrhages with neurodegeneration were observed in the spinal cord. Based on the histopathological findings, representative samples, including lung, liver, mesenteric lymph node, blood obtained from the jugular vein, and fluid sample of the ascites, were inoculated on tryptic soy agar and blood agar for routine bacterial isolation. Each isolated bacterial colony was streaked aseptically onto tryptic soy agar and blood agar for pure culture. After then, polymerase chain reaction (PCR) was performed for further identification of pathogenic microorganisms. PCR identified Escherichia fergusonii, Shewanella haliotis, Enterococcus faecalis, and Staphylococcus schleiferi. E. fergusonii was considered the primary etiologic agent in this case since it was the only species identified in all representative samples. The cause of death in this animal was E. fergusonii sepsis. To the best of our knowledge, this is the first case of neonatal sepsis associated with E. fergusonii infection in a dolphin, and suggests E. fergusonii as an opportunistic pathogen associated with sepsis in dolphins

    Optimal timing of endoscopic retrograde cholangiopancreatography for acute cholangitis associated with distal malignant biliary obstruction

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    Background There is a lack of studies regarding the optimal timing for endoscopic retrograde cholangiopancreatography (ERCP) in patients with cholangitis caused by distal malignant biliary obstruction (MBO). This study aims to investigate the optimal timing of ERCP in patients with acute cholangitis associated with distal MBO with a naïve papilla. Methods A total of 421 patients with acute cholangitis, associated with distal MBO, were enrolled for this study. An urgent ERCP was defined as being an ERCP performed within 24 h following emergency room (ER) arrival, and early ERCP was defined as an ERCP performed between 24 and 48 h following ER arrival. We evaluated both 30-day and 180-day mortality as primary outcomes, according to the timing of the ERCP. Results The urgent ERCP group showed the lowest 30-day mortality rate (2.2%), as compared to the early and delayed ERCP groups (4.3% and 13.5%) (P < 0.001). The 180-day mortality rate was lowest in the urgent ERCP group, followed by early ERCP and delayed ERCP groups (39.4%, 44.8%, 60.8%; P = 0.006). A subgroup analysis showed that in both the primary distal MBO group, as well as in the moderate-to-severe cholangitis group, the urgent ERCP had significantly improved in both 30-day and 180-day mortality rates. However, in the secondary MBO and mild cholangitis groups, the difference in mortality rate between urgent, early, and delayed ERCP groups was not significant. Conclusions In patients with acute cholangitis associated with distal MBO, urgent ERCP might be helpful in improving the prognosis, especially in patients with primary distal MBO or moderate-to-severe cholangitis

    Cadmium resistance in tobacco plants expressing the MuSI gene

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    MuSI, a gene that corresponds to a domain that contains the rubber elongation factor (REF), is highly homologous to many stress-related proteins in plants. Since MuSI is up-regulated in the roots of plants treated with cadmium or copper, the involvement of MuSI in cadmium tolerance was investigated in this study. Escherichia coli cells overexpressing MuSI were more resistant to Cd than wild-type cells transfected with vector alone. MuSI transgenic plants were also more resistant to Cd. MuSI transgenic tobacco plants absorbed less Cd than wild-type plants. Cd translocation from roots to shoots was reduced in the transgenic plants, thereby avoiding Cd toxicity. The number of short trichomes in the leaves of wild-type tobacco plants was increased by Cd treatment, while this was unchanged in MuSI transgenic tobacco. These results suggest that MuSI transgenic tobacco plants have enhanced tolerance to Cd via reduced Cd uptake and/or increased Cd immobilization in the roots, resulting in less Cd translocation to the shoots

    Clear Cell "Sugar" Tumor of the Lung: A Well-Enhanced Mass with an Early Washout Pattern on Dynamic Contrast-Enhanced Computed Tomography

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    Clear cell tumor of the lung is a rare and very unusual benign pulmonary tumor. As clear cell tumor of the lung contains abundant cytoplasmic glycogen, this tumor is called "sugar tumor". We report a case of sugar tumor in a 64-yr-old man presenting as a round pulmonary nodule. On dynamic computed tomography (CT) scans, the solitary pulmonary nodule showed early wash-in enhancement with an early washout pattern like a lung malignancy. The patient underwent wedge resection for the tumor. Pathologic examination, including immunohistochemical studies, revealed that the nodule was a benign clear cell tumor, so-called "sugar tumor". Because only a small number of cases have been reported previously, clinical aspects, radiological characteristics on dynamic contrast-enhanced CT, and differential diagnosis of the tumor are not well established. Herein we present a clear cell tumor of the lung and discuss the clinical, radiological, and pathological features of the tumor

    Exendin-4 Improves Steatohepatitis by Increasing Sirt1 Expression in High-Fat Diet-Induced Obese C57BL/6J Mice

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    The effects of exendin-4 on Sirt1 expression as a mechanism of reducing fatty liver have not been previously reported. Therefore, we investigated whether the beneficial effects of exendin-4 treatment on fatty liver are mediated via Sirt1 in high-fat (HF) diet-induced obese C57BL/6J mice and related cell culture models. Exendin-4 treatment decreased body weight, serum free fatty acid (FA), and triglyceride levels in HF-induced obese C57BL/6J mice. Histological analysis showed that exendin-4 reversed HF-induced hepatic accumulation of lipids and inflammation. Exendin-4 treatment increased mRNA and protein expression of Sirt1 and its downstream factor, AMPK, in vivo and also induced genes associated with FA oxidation and glucose metabolism. In addition, a significant increase in the hepatic expression of Lkb1 and Nampt mRNA was observed in exendin-4-treated groups. We also observed increased expression of phospho-Foxo1 and GLUT2, which are involved in hepatic glucose metabolism. In HepG2 and Huh7 cells, mRNA and protein expressions of GLP-1R were increased by exendin-4 treatment in a dose-dependent manner. Exendin-4 enhanced protein expression of Sirt1 and phospho-AMPKα in HepG2 cells treated with 0.4 mM palmitic acid. We also found that Sirt1 was an upstream regulator of AMPK in hepatocytes. A novel finding of this study was the observation that expression of GLP-1R is proportional to exendin-4 concentration and exendin-4 could attenuate fatty liver through activation of Sirt1

    Strategies for Natural Product Discovery by Unlocking Cryptic Biosynthetic Gene Clusters in Fungi

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    Recent advancements in genome sequencing and bioinformatic analysis of fungal genomes have revealed that fungi possess cryptic or silent biosynthetic gene clusters (BGCs). This discovery suggests that our understanding of the universe of fungal secondary metabolomes is limited. In this review, we summarize recent strategies for activating cryptic BGCs in fungi, identify fungal secondary metabolites, and highlight their biological activities. We also briefly discuss the isolation and purification methods for these compounds. Our focus is on genetics-dependent and genetics-independent approaches for activating cryptic BGCs in fungi. Using the strategies discussed here, cryptic fungal natural products hold significant potential as a source for the discovery of new drug candidates

    Flexible Nanoporous Wo3-X Nonvolatile Memory Device

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    Flexible resistive random access memory (RRAM) devices have attracted great interest for future nonvolatile memories. However, making active layer films at high temperature can be a hindrance to RRAM device fabrication on flexible substrates. Here, we introduced a flexible nanoporous (NP) WO3-x RRAM device using anodic treatment in a room-temperature process. The flexible NP WO3-x RRAM device showed bipolar switching characteristics and a high ION/IOFF ratio of ∼105. The device also showed stable retention time over 5 × 105 s, outstanding cell-to-cell uniformity, and bending endurance over 103 cycles when measured in both the flat and the maximum bending conditions
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