• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.553-560
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• 2001

Objective : The objective of this study was to determine the photodynamic therapeutic response of U-87 human glioma cell in vitro as well as in the nude rat xenograft model using photofrin as photosensitizer. Material and Method : U-87 cells were cultured on 96-well culture plates, photofrin(Quadralogic Technologies Inc., Vancouver, Canada) was added into the cell culture medium at concentration of $1{\mu}g/ml$, $2.5{\mu}g/ml$, $5{\mu}g/ml$, $10{\mu}g/ml$ and $20{\mu}g/ml$. 24 hour after drug treatment, cells were treated with optical(632nm) irradiation of $100mJ/cm^2$, $200mJ/cm^2$ and $400mJ/cm^2$. Photofrin(12.5mg/kg, i.p.) was administered to 28 nude rats containing intracerebral U-87 human glioma as well as 26 normal nude rats. 48 hours after administration, animals were treated with optical irradiation(632nm) of $35J/cm^2$, $140J/cm^2$ and $280J/cm^2$ to exposed tumor and normal brain. The photofrin concentration was measured in tumor and normal brain in a separate population of animals. Results : By MTT assay, there was 100% cytotoxicity at any dose of photofrin with optical irradiation of $200mJ/cm^2$ and $400mJ/cm^2$. But at the optical irradiation of $100mJ/cm^2$ cells were killed in dose dependent manner 28.5%, 49.1%, 54.4%, 78.2%, and 84.6% at concentration of $1{\mu}g/ml$, $2.5{\mu}g/ml$, $5{\mu}g/ml$, $10{\mu}g/ml$ and $20{\mu}g/ml$, respectively. Dose dependent PDT lesions in both tumor and normal brain were observed. In the tumor lesion, only superficial tissue damage was found with optical irradiation of $35J/cm^2$. However, in the optical irradiation group of $140J/cm^2$ and $280J/cm^2$ the volume of lesions was measured of $7.2mm^3$ and $14.0mm^3$ for treatment at $140J/cm^2$ and $280J/cm^2$, respectively. The U-87 bearing rats showed a photofrin concentration in tumor tissue of $6.53{\pm}2.16{\mu}g/g$, 23 times higher than that found in the contralateral hemisphere of $0.28{\pm}0.15{\mu}g/g$. Conclusion : Our data indicate that the U-87 human glioma in vitro and in the xenografted rats is responsive to PDT. At these doses, a reproducible injury can be delivered to human glioma in this model. Strategies to spare the normal brain collateral damage are being studied.

• Journal of Intelligence and Information Systems
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• v.20 no.4
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• pp.141-154
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• 2014

The adoption of International Financial Reporting Standards (IFRS) is the one of important issues in the recent accounting research because the change from local GAAP (Generally Accepted Accounting Principles) to IFRS has a substantial effect on accounting information. Over 100 countries including Australia, China, Canada and the European Union member countries adopt IFRS (International Financial Reporting Standards) for financial reporting purposes, and several more including the United States and Japan are considering the adoption of IFRS (International Financial Reporting Standards). In Korea, 61 firms voluntarily adopted Korean International Financial Reporting Standard (K-IFRS) in 2009 and 2010 and all listed firms mandatorily adopted K-IFRS (Korea-International Financial Reporting Standards) in 2011. The adoption of IFRS is expected to increase financial statement comparability, improve corporate transparency, increase the quality of financial reporting, and hence, provide benefits to investors This study investigates whether recognized accounts receivable discounting (AR discounting) under Korean International Financial Reporting Standard (K-IFRS) is more value relevant than disclosed AR discounting under Korean Generally Accepted Accounting Principles (K-GAAP). Because more rigorous standards are applied to the derecognition of AR discounting under K-IFRS(Korea-International Financial Reporting Standards), most AR discounting is recognized as a short term debt instead of being disclosed as a contingent liability unless all risks and rewards are transferred. In this research, I try to figure out industrial responses to the changes in accounting rules for the treatment of accounts receivable toward more strict standards in the recognition of sales which occurs with the adoption of Korea International Financial Reporting Standard. This study examines whether accounting information is more value-relevant, especially information on accounts receivable discounting (hereinafter, AR discounting) is value-relevant under K-IFRS (Korea-International Financial Reporting Standards). First, note that AR discounting involves the transfer of financial assets. Under Korean Generally Accepted Accounting Principles (K-GAAP), when firms discount AR to banks before the AR maturity, firms conventionally remove AR from the balance-sheet and report losses from AR discounting and disclose and explain the transactions in the footnotes. Under K-IFRS (Korea-International Financial Reporting Standards), however, most firms keep AR and add a short-term debt as same as discounted AR. This process increases the firms' leverage ratio and raises the concern to the firms about investors' reactions to worsening capital structures. Investors may experience the change in perceived risk of the firm. In the study sample, the average of AR discounting is 75.3 billion won (maximum 3.6 trillion won and minimum 18 million won), which is, on average 7.0% of assets (maximum 38.6% and minimum 0.002%), 26.2% of firms' accounts receivable (maximum 92.5% and minimum 0.003%) and 13.5% of total liabilities (maximum 69.5% and minimum 0.004%). After the adoption of K-IFRS (Korea-International Financial Reporting Standards), total liabilities increase by 13%p on average (maximum 103%p and minimum 0.004%p) attributable to AR discounting. The leverage ratio (total liabilities/total assets) increases by an average 2.4%p (maximum 16%p and minimum 0.001%p) and debt-to-equity ratio increases by average 14.6%p (maximum 134%p and minimum 0.006%) attributable to the recognition of AR discounting as a short-term debt. The structure of debts and equities of the companies engaging in factoring transactions are likely to be affected in the changes of accounting rule. I suggest that the changes in accounting provisions subsequent to Korea International Financial Reporting Standard adoption caused significant influence on the structure of firm's asset and liabilities. Due to this changes, the treatment of account receivable discounting have become critical. This paper proposes an intelligent diagnostic system for estimating negative impact on stock value with self-organizing maps and case based reasoning. To validate the usefulness of this proposed model, real data was analyzed. In order to get the significance of this proposed model, several models were compared to the research model. I found out that this proposed model provides satisfactory results with compared models.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.2
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• pp.62-69
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• 2009

This study aimed to analyze citizen awareness of the transforming of a former military site in the city into use as an urban park, and to determine the direction of park creation in the context of urban regeneration. The study focused on the city of Uijungbu, so-called "representative military city" of Korea, which has over eight US military army corps in CBD and which islocated on the northside of Seoul. The questionnaire survey was carried out in the year of 2006, during two months from 1 June till 30 July. The research was carried out by book review as a theoretical base and a questionnaire survey to analyze citizen awareness. The conclusions of this study were as follows. 1. Areas that have been transformed from a former military site to large urban parks for the promotion of economic, social, environmental, and aesthetical value in the context of urban regeneration include Downsview Park(Toronto, Canada), and Great Park(Irvine, CA U.S.A). 2. The citizens of Euijungbu emphasized having casual rest and recreational functions in an urban park, but were also concerned with the promotion of cultural image, activation of the city's economy, etc. 3. The citizens preferred to use the former military site for a park instead of for residential and commercial purposes to introduce cultural facilities and encourage economic activation. 4. All results of this study proposed to use the former military site for encouraging and activating the urban economy, cultural promotion, social reconciliation and aesthetic value by the transforming the site into a large, multi-use park in the context of urban regeneration.

• Progress in Medical Physics
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• v.19 no.4
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• pp.276-284
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• 2008

A computed tomography (CT) is a powerful system for the effectively fast and accurate diagnosis. The CT system, therefore, has used substantially and developed for improving the performance over the past decade, resulting in growing concerns over the radiation dose from the CT. Advanced CT techniques, such as a multidetector row CT scanner and dual energy or dual source CT, have led to new clinical applications that could result in further increases of radiation does for both patients and workers. The objective of this study was to review the international guidelines of the shielding requirements for a CT facility required for a new installation or when modifying an existing one. We used Google Search Engine to search the following keywords: computed tomography, CT regulation or shield or protection, dual energy or dual source CT, multidetector CT, CT radiation protection, and regulatory or legislation or regulation CT. In addition, we searched some special websites, that were provided for sources of radiation protection, shielding, and regulation, RSNA, AAPM, FDA, NIH, RCR, ICRP, IRPA, ICRP, IAEA, WHO (See in Table 1 for full explanations of the abbreviations). We finally summarized results of the investigated materials for each country. The shielding requirement of the CT room design was very well documented in the countries of Canada, United States of America, and United Kingdom. The wall thickness of the CT room could be obtained by the iso-exposure contour or the point source method. Most of documents provided by international organizations were explained in importance of radiation reduction in patients and workers. However, there were no directly-related documents of shielding and patient exposure dose for the dual energy CT system. Based international guidelines, the guideline of the CT room shielding and radiation reduction in patients and workers should be specified for all kinds of CT systems, included in the dual energy CT. We proposed some possible strategies in this paper.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.306-315
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• 1999

Purpose: We performed this study to evaluate the process of radiation induced apoptosis in A431 skin epithelial cancer cell line. Materials and Methods: Low to high dose radiation (0, 2, 5, 10, 25 Gy) was given to A431 cells by Cs-137 cell irradiator. Apoptosis was evaluated by cell morphology, dye exclusion test, and DNA laddering. Results: Cell viability decreased as the radiation dose increased. Number of apoptotic bodies increased as radiation dose increased. It increased most significantly at 12 hours after irradiation. Lactate dehydrogenase activity in culture medium increased according to radiation dose and time after irradiation. DNA ladders could be identified in irradiated cells, but, it had no correlation with radiation dose or time after irradiation. Conclusion: Radiation-induced apoptosis which was the main course of cell death in A431 cells could be analyzed quantitatively by counting apoptotic bodies under microscope. Apoptosis increased as radiation dose increased.

• Korean Journal of Environmental Agriculture
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• v.12 no.1
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• pp.41-49
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• 1993

The Study was conducted to develope the low temperature tolerant methane-producing bacteria(LTTB) and to increase the efficiency of anaerobic fermentation for the treatment of agricultural and livestock wastes at low temperature. The samples were collected from muddy soil, water logged sediment, organic layer and anaerobic sludge at three latitudes, $34.8{\sim}37.4\;^{\circ}N(Korea)$, $41.4\;^{\circ}N(USA)$ and $54.5{\sim}56.9\;^{\circ}N(Canada)$. They were used for determination of the methanogenesis rates for isolation and identification of the LTTB. The methanogenesis rate of smaples at low temperature were higher in the cellulose medium than methanol medium. The methanogenesis rate in the samples of subarctic region were $15{\sim}19$ moles/ml during 30 days at low temperature($8\;^{\circ}C$), whereas not detected in the samples of temperate region. The methanogenesis rate in the enrichment culture of subarctic samples were inhibited by the $40\;{\mu}g/ml$ of streptomycin + vancomycin or ampicillin + oleandomycin which were not effect to the methanogens. An inhabitation of high temperature tolerant methane producing bacteria was identified in the samples of temperate region, whereas that of the LTTB growing at $8{\sim}13^{\circ}C$ was identified in the subarctic region.

• Clinical and Experimental Pediatrics
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• v.45 no.2
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• pp.247-255
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• 2002

Purpose : This study was undertaken to obtain basic data about the megakaryocyte colony formation of fetal liver cells by using immunocytochemical staining and ex vivo culture with growth factors. Methods : The mononuclear cells were isolated from fetal liver and bone marrow with idiopathic thrombocytopenic purpura(ITP) and pancytopenia. These mononuclear cells were cultured in $MegaCult^{TM}-C$(Stem Cell Tech, Canada) media in the presence of growth factors and CFU-Megakaryocyte( CFU-Mk) colonies were counted on day 12. The expansion of CD34+ and CD41+ cell was analyzed by flow cytometry after 5 days incubation using flask culture. Results : The numbers of CFU-Mk colonies of mononuclear cells obtained from fetal liver in the 11th week gestational age were more than those in the 19th week specimens; growth factors could not enhance the colony expansion in all cases. Total numbers of CFU-Mk colony of fetal liver cells were higher than bone marrow from ITP or pancytopenia groups. The numbers of pure or large CFU-Mk colonies of fetal liver cells were also higher than bone marrow specimens. The rate of CD34+ cell expression of fetal liver was increased after flask culture and the enhancement effect of epression was seen only in cases which added thrombopoietin. The rate of CD41+ cell expression of fetal liver was increased after incubation, but the enhancement effect of growth factors was unclear. Conclusion : This study revealed good results about the megakaryocyte colony assay of fetal liver mononuclear cells using $MegaCult^{TM}-C$ media. This study suggests that the fetal liver could be a good source of megakaryocytic progenitor cells for clinical application in hematopoietic stem cell transplantation.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.161-167
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• 2011

The soil moisture has an important effect on growth and development of highbush blueberry (HB), mainly because the root system, devoid of root hairs, is superficial. Moreover, the texture and organic matter content of Korean soil is different from the main producing counties, such as USA and Canada. To facilitate the growth and development of HB and long-term maintenance of productivity, the research related to soil moisture condition in Korea should be the priority. This study was performed to investigate the growth properties of the HB in various soil moisture conditions in order to determine the irrigation trigger point and optimum soil water potential. The texture of soil used in this experiment was loam. For the experiments, the soil was mixed with peatmoss at a rates 30% (v/v). Irrigation was scheduled at -3, -4, -5, -8, -15 and -22 kPa soil water potential then investigated leaf macronutrient, bush growth, and fruit properties. The leaf K content of HB showed the same trend in the soil water potential, but Leaf P and Mg content was highest in -5 and -22 kPa, respectively. The productivity and growth amount of HB showed the peak at the range of -4~-8 kPa as normal distribution pattern, and greatly decreased at above -15 kPa. Total dry weight and Cane diameter were highest at -4 kPa, plant width, fruit weight and yield were highest at -5 kPa, and plant height, cane number and shoot tension were highest at -8 kPa. Soluble solids content showed same trend in the soil water potential, but titratable acidity, anthocyanins and total polyphenols were not significantly different. Therefore, the optimal soil water potential for the development and a maximum production of HB were a range of -4~-8 kPa, and the recommended ideal irrigation trigger point was within -15 kPa.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.366-373
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• 2020

According to Article 77 of the Ship Safety Act and Article 97(2) of the Enforcement Ordinance of the Ministry, the Recognized Organization (RO) personnel (ship surveyors) responsible for statutory survey shall have educational qualifications and experience in a specific field or obtain a license under the National Technical Qualifications Act. However, graduates from maritime high schools and those who completed the short-term course of the Ocean Polytec did not satisfy the qualification standards for the RO personnel since they did not graduate from the departments of maritime/fisheries or shipbuilding. Major shipping countries such as the United Kingdom, the United States, and Canada use the IACS (International Association of Classification Societies) regulations, and the Ship Safety Act in Japan has eliminated the qualification requirements for ship surveyors. In particular, under the IMO (International Maritime Organization) and IACS regulations, the RO personnel shall have as a minimum the following formal educational background: a degree or equivalent qualification from a tertiary institution recognized within a relevant field of engineering or physical science (minimum two years' program); or a relevant qualification from a marine or nautical institution and relevant sea-going experience as a certified ship officer; and competency in the English language commensurate with their future work. Considering that Article 17 of the Enforcement Decree on Public Officials Appointment Examinations prohibits educational restrictions and there are no educational restrictions on the qualifications of British and Japanese surveyors, if the maritime high school graduates have sufficient sea-going experience, education, and training, they could be recognized as meeting the qualification requirements. Moreover, those who completed the short-term course of the Ocean Polytec could also be recognized as meeting the qualification requirements because they are required to have at least a professional bachelor's degree (in the case of a third-class CoC (Certificate of Competancy)) and some sea-going experience after completion.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.153-180
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• 2020

This study is meaningful in finding out what legal and policy issues need to be improved in order to foster the aircraft industry, which is relatively underdeveloped compared to the fact that some heavy industries, such as the automobile industry and shipbuilding industry, have achieved a high level of production and technology globally. Korea's aircraft industry has been growing at a slower pace than other industries, largely due to the country's economic growth and the lack of a market structure to properly use variables such as the level of development in related industries, aircraft technology and demand for aircraft manufacturing. While most industries are privately led by the market structure of the competition system, heavy industries such as the aircraft industry generally grow under the market structure of the incomplete competition system, because only by securing huge initial investment costs, high technology, and sufficient demand, they can maintain minimum economic feasibility. The Korean aircraft industry was focused on developing and mass-producing military aircraft focusing on military demand, but it sought to turn the tide by signing the BASA (Bileral Aviation Safety Agreement) with the U.S. A preliminary feasibility study was conducted in 2010 to develop next-generation medium-sized aircraft, but was cancelled due to differences in position with Canada's Bombardier, which is subject to the concourse, and Korea Aerospace Industries (KAI) is pushing for the production of Bombardier's Q400 license on its own. Compared to the mid-to-large sized civil aircraft that are facing difficulties in development, KAI and KARI are successfully developing technologies to unmanned aerial vehicles and civil helicopters. In addition, the unmanned aerial vehicle sector is not yet suitable for manufacturers that have an exclusive global influence, so we believe that it is necessary to pursue government-led research and development projects with a focus on the areas of commercial helicopters and unmanned aerial vehicles in order to foster the aircraft industry in the future. In addition, since military aircraft such as KT-1 and T-50 are currently being exported smoothly, and it cannot be overlooked that the biggest demand for aircraft manufacturing in the Korea is the military, it is necessary to push forward national R&D projects and defense R&D program simultaneously to enable both civilian-military development. However, there are many differences between the two projects in the way they are implemented, the department in charge and the royalty system. Through this study, we learned about the technology ownership and implementation rights of national R&D projects and defense R&D programs, as well as the royalty system. In addition, problems with the system were identified and improvement measures were derived.