1,707 research outputs found

    A Comparative Analysis of Three Major Transfer Airports in Northeast Asia Focusing on Incheon International Airport Using a Conjoint Analysis

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    Due mainly to the privatization and commercialization of airline companies and deregulation of the aviation rules, the demand for air transport has continuously been increasing. Airport authorities state that transfer passengers, who contribute to the large portion of the airportsā€™ profits, are gaining much more importance, particularly in the Northeast Asia region where the air transport industry is very vital. Therefore, this study aims to investigate the competitiveness of IIA (Incheon International Airport) with other major airports located in Northeast Asia in passenger transfers made between Southeast Asia and China to North America using Conjoint Analysis. Results have indicated that airport brand is the most important attribute for the competitiveness of airport, followed by cost, connectivity and duty free shops. In further analysis focusing on brand value of the three airports measured by the use of transfer passengers, it was revealed that IIA needs more effort in developing their brand identity to become the leading transfer hub airport. Based on the results, recommendations for increasing the brand value have also been suggested

    New Trade Restrictive Measures and Exports: Evidence from South Korea

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    The world economy recently witnessed a surge in trade remedies and non-tariff measures (NTMs) as new trade-restrictive measures. This study attempts to provide empirical evidence on the effects of new trade-restrictive measures, such as antidumping, countervailing measures, technical barriers to trade, and sanitary and phytosanitary measures on trade. By using the Korean product-level export data and the new NTM data, we find that new trade-restrictive measures in trade can depend on the affected sectors and imposing countries. Exports can be adversely affected by new trade-restrictive measures in their concentrated sectors taken by importing developed countries. We also find the threatening effects of trade remedy before this investigation. However, new trade-restrictive measures imposed by importing developing countries can have positive impact on trade, particularly an increase in consumers trust in product quality and decrease in asymmetric information. Results imply that the government of an exporting party should enhance trade policies by considering the heterogeneous effects of new trade-restrictive measures across industries and trading partners.We thank the Bank of Korea for providing financial support

    Prolonged Activation of ERK Contributes to the Photorejuvenation Effect in Photodynamic Therapy in Human Dermal Fibroblasts

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    Photodynamic therapy (PDT) is known to be effective in the photorejuvenation of photoaged skin. However, the molecular mechanisms of rejuvenation by PDT remain elusive. In this study, we aimed to understand the molecular events occurring during the photorejuvenation after PDT in dermal fibroblasts in vitro. First, we found that PDT conditions resulted in an increased fibroblast proliferation and motility in vitro. Under this condition, cells had increased intracellular reactive oxygen species (ROS) production. Importantly, PDT induced a prolonged activation of extracellular signalā€“regulated kinase (ERK) with a corresponding increase in matrix metalloproteinase (MMP)-3 and collagen type IĪ± messenger RNA and protein. Moreover, inhibition of PDT-induced ERK activation significantly suppressed fibroblast proliferation and expression of MMP-3 and collagen type IĪ± following PDT. In addition, NAC (an antioxidant) inhibited PDT-induced fibroblast proliferation and ERK activation indicating that prolonged ERK activation and intracellular ROS contribute to the proliferation of fibroblasts and the dermal remodeling process for skin rejuvenation. We also identified increased collagen volume and decreased elastotic materials that are used as markers of photoaging in human skin samples using histochemical studies. Results from this study suggest that intracellular ROS stimulated by PDT in dermal fibroblasts lead to prolonged activation of ERK and, eventually, fibroblast proliferation and activation. Our data thus reveal a molecular mechanism underlying the skin rejuvenation effect of PDT

    Nontuberculous mycobacterial infection in a clinical presentation of Fitz-Hugh-Curtis syndrome: a case report with multigene diagnostic approach

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    BACKGROUND: Fitz-Hugh-Curtis syndrome (FHCS) is caused by inflammation of perihepatic capsules associated with pelvic inflammatory disease. In recent years, infections with nontuberculous mycobacteria (NTM) have been increasingly occurring in immunocompromised and immunocompetent patients. However, NTM has never been reported in patients with FHCS. We present the first case of a patient with extrapulmonary NTM infection in a clinical presentation of FHCS. CASE PRESENTATION: A 26-year-old Korean woman presented with right upper quadrant and suprapubic pain. She was initially suspected to have FHCS. However, she was refractory to conventional antibiotic therapy. Laparoscopy revealed multiple violin-string adhesions of the parietal peritoneum to the liver and miliary-like nodules on the peritoneal surfaces. Diagnosis of NTM was confirmed by the polymerase chain reaction analysis results of biopsy specimens that showed caseating granulomas with positive acid-fast bacilli. Treatment with anti-NTM medications was initiated, and the patientā€™s symptoms were considerably ameliorated. CONCLUSIONS: An awareness of NTM as potential pathogens, even in previously healthy adults, and efforts to exclude other confounding diseases are important to establish the diagnosis of NTM disease. NTM infection can cause various clinical manifestations, which in the present case, overlapped with the symptoms of perihepatic inflammation seen in FHCS

    Characteristics of the aberrant pyramidal tract in comparison with the pyramidal tract in the human brain

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    <p>Abstract</p> <p>Background</p> <p>The aberrant pyramidal tract (APT) refers to the collateral pathway of the pyramidal tract (PT) through the medial lemniscus in the midbrain and pons. Using diffusion tensor tractography (DTT), we investigated the characteristics of the APT in comparison with the PT in the normal human brain.</p> <p>Results</p> <p>In thirty-four (18.3%, right hemisphere: 20, left hemisphere: 14) of the 186 hemispheres, the APTs separated from the PT at the upper midbrain level, descended through the medial lemniscus from the midbrain to the pons, and then rejoined with the PT at the upper medulla. Nine (26.5%) of the 34 APTs were found to originate from the primary somatosensory cortex without a primary motor cortex origin. Values of fractional anisotropy (FA) and tract volume of the APT were lower than those of the PT (<it>P </it>< 0.05); however, no difference in mean diffusivity (MD) value was observed (<it>P ></it>0.05).</p> <p>Conclusion</p> <p>We found that the APT has different characteristics, including less directionality, fewer neural fibers, and less origin from the primary motor cortex than the PT.</p

    Comb-rooted multi-channel synthesis of ultra-narrow optical frequencies of few Hz linewidth

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    We report a multi-channel optical frequency synthesizer developed to generate extremely stable continuous wave lasers directly out of the optical comb of an Er-doped fiber oscillator. Being stabilized to a high-finesse cavity with a fractional frequency stability of 3.8Ɨ10āˆ’153.8\times10^{-15} at 0.1 s, the comb-rooted synthesizer produces multiple optical frequencies of ultra-narrow linewidth of 1.0 Hz at 1 s concurrently with an output power of tens of mW per each channel. Diode-based stimulated emission by injection locking is a key mechanism that allows comb frequency modes to sprout up with sufficient power amplification but no loss of original comb frequency stability. Channel frequencies are individually selectable with a 0.1 GHz increment over the entire comb bandwidth spanning 4.25 THz around a 1550 nm center wavelength. A series of out-of-loop test results is discussed to demonstrate that the synthesizer is able to provide stable optical frequencies with the potential for advancing diverse ultra-precision applications such as optical clocks comparison, atomic line spectroscopy, photonic microwaves generation, and coherent optical telecommunications.Comment: 19 pages, 4 figure

    Structure stability evaluation of offshore heave compensator using multi-body dynamics analysis method

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    Heave compensator attenuate vessel heave motion during drilling operation of drillship. Heave compensator functions as damping form motion of drillship, such as principle spring of suspension system. The load transfers on the parts of heave compensator. Stress and deformation of all parts is evaluated to diagnose the stability of the compensator. This study makes a decision on the safety of structure. Results of analysis confirm the structure stability of heave compensator for simulation. This result can be used as data for structural analysis to determine safety of a structure
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