• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.173-180
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• 2001

The physicochemical characteristics such as glass transition temperature (Tg), surface energy, swelling and FT-IR of [P(AA-co-PEGMM)], a copolymer of acrylic acid (AA) and polyethyleneglycol monoethylether mono methacrylate (PEGMM), were evaluated. The Tg of [P(AA-co-PEGMM)] decreased with increasing PEGMM content. [P(AA-co-PEGMM)] with 18 mole% PEGMM had the Tg of about $40^{\circ}C$, the similar physiological temperature of human. Moreover, [P(AA-co-PEGMM)] with lower PEGMM content had higher hydration and expected lower mucoadhesive strengths. To predict the mucoadhesiveness of [P(AA-co-PEGMM)] films, the contact angle of films were measured. With the increasing content of PEGMM of films, the contact angle was increased and the higher mucoadhesive forces was expected. ATR-FTIR studies revealed that the addition of the PEG moiety in AA increased the potential of hydrogen bonding for [P(AA-co-PEGMM)] as compared to cross linking polyacrylic acid (cr-PAA) because the oxygen in the repeat unit of PEG contributed in the formation of hydrogen bonding in the presence of mucin solution.

• The Korean Journal of Pharmacology
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• v.7 no.1
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• pp.37-52
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• 1971

It has been demonstrated repeatedly that the administration of ethionine, a methionine analogue, will produce destruction of pancreatic tissue and liver cells. Destruction of acinar cells of pancreas by the administration of excess methionine similar to that seen after feeding diets supplemented with ethionine was also reported, but the liver was not involved by this amino acid. In an attempt to reproduce the results of these investigators the tissue damages were found to be slight and seen only irregulary in rats receiving ethionine on a complete diet and the result of tissue damages by excess methionine were also controversial. The present studies describe the toxicity of dietary supplemented ethionine and methionine to liver and pancreas in rats fed a low protein diet. Hundred five albino rats weighing around 120 gm were divided into three groups as follows; 1) Control group: A low protein diet containing 8% casein was fed throughout the experimental period. 2) Methionine group: A low protein diet (7% casein) supplemented with 1% methionine was used. 3) Ethionine group: A similar diet as methionine group except the supplementation of 1% ethionine instead of methionine was used. Five animals per wee from each group were killed for 6 weeks. The liver and pancreas were fixed in 10% formalin and histologic sections were prepared and stained with hematoxylin eosin. Serum amylase was expressed as much of glucose liberated from a starch substrate. The glucose was determined by the method of Nelson (1944). Serum glutamic pyruvic transaminase (SGPT) and glutamic oxaloacetic transaminase (SGOT) were determined by the technique described in Sigma Bulletin.

• Transactions of Materials Processing
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• v.14 no.9 s.81
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• pp.798-803
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• 2005

In this paper, the six sigma scheme together with the rigid-viscoplastic finite element method is employed to obtain the optimal metal flow lines of a hot forging according to the six sigma processes, i.e., five steps such as define, measure, analyze, improve and control. Each step is investigated in detail to meet customer's requirements through improvement of product quality. A forging simulator is used for analysis of the metal flow lines of the hot forging, manufactured by a hot press forging machine, under various conditions of major factors determined at each step. The analyzed results are examined in order to reveal the effects of major factors on the metal flow lines and the formed shapes. The effects are then used to find an optimal process and the optimal process with die is devised and tested. The comparison between the required metal flow lines and the experiments shows that the approach is effective for optimal process design in hot forging considering metal flow lines.

• Korean Journal of Pharmacognosy
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• v.30 no.1
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• pp.7-11
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• 1999

The present work was carried out to examine the effect of costunolide on the growth of several cells and characteristics of U-937 human leukemia-derived cell line. Costunolide produced a potent antitumor activity in vitro dependent on concentration against several tumor cells such as P-388, L-1210 leukemia and SNU-5 stomach cancer cells. However, it showed less cytotoxicity on normal cells such as Maccaccus rheus monkey kidney cells (MA-104) up to 200 ${\mu}M$ concentration. An effect of cell differentiation by costunolide was assessed by its ability to reduce nitroblue tetrazolium (NBT), and to induce phagocytosis of latex particles. In order to establish whether costunolide induces U-937 cells to differentiate toward macrophage or granulocyte, esterase activities was measured. Based on these results, we found that costunolide having cytotoxicity on U-937 human leukemia cells was explained through differentiation inducing activity.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.301-307
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• 2011

In this paper, effects of major design parameters of cold forging dies on die mechanics are quantitatively investigated with emphasis on shrink fit using a thermoelastic finite element method. A ball-stud cold forging process found in a cold forging company is selected as a test process and the effects of die insert material, magnitude of shrink fit, dimension of shrink ring, number of shrink rings, partition of die insert and clamping force on effective stress and circumferential stress are analyzed. It has shown that the number of shrink rings, magnitude of shrink fit, and Young's modulus of die insert material have strong influence on compressive circumferential stress in die insert but that the influence of the other design parameters is relatively weak.

• Parasites, Hosts and Diseases
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• v.39 no.4
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• pp.267-283
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• 2001

In endemic areas of Taenia tapeworms in Korea, most of the reports showed that T. saginata was dominant over T. solium, but eating pigs is the dominant habit over eating cattle. Why do they have more T saginata despite lower consumption of beef This problem actually has long been recognized but until recently there has been no intensive trial to give a scientific explanation on this epidemiological enigma. By summing up the data published between the years 1963 and 1999, the ratio of armed versus unarmed tapeworms in humans was estimated at approximately 1 :5. The ratio of pig-eaters versus cattle-eaters, however, was approximately 5: 1. This inconsistency could be explained with the recently described T. asiatica, which infects humans through the eating of pig's viscera. We re-evaluate the importance of the consumption of visceral organ of pigs, leading us to an improved epidemiological understanding of the T. asiatica infection together with co-existing T. saginata and T. solium in Korea.

• Knowledge Management Research
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• v.17 no.1
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• pp.155-174
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• 2016

Recent years, a smartphone has been playing a role of searching, booking, and decision-makings in the tourism industry through tourists' user experiences and engagements. This study investigated the tourists' behavior toward smartphone usage regarding Chinese visitors who were ranked in Korea inbound tourism. This research model formulated two types of usage which identified explorlative use and exploitive use and the antecedent relationships of user empowerment including user competence, user impact, usage meaning, user trust. We analyzed SmartPLS2.0 for the hypotheses and found that first, user competence has a positive influence both of exploitative use and explorative use, second, user impact has a positive influence on exploitative use, but has not influenced on explorative use, third, usage meaning has not influence on exploitive use, but has a postitive influence on explorative use, and finally user trust has influence on both of exploitive and explorative use. Based on the results we found, we suggested Chinese tourists' smartphone usages' behaviors and theoretical and practical implications.

• Journal of Korean Society of Rural Planning
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• v.14 no.1
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• pp.73-82
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• 2008

Taekwondo, Korean traditional martial art as one of the ten Korean cultural symbols, has acquired a reputation for introducing and globalizing Korean culture together with its standing as official Olympic Game in 2000, Sydney, Australia. Nevertheless the World Taekwondo Headquarters, Kukkiwon, which is an exclusive Taekwondo institution only accommodates for three thousand persons. Considering the worldwide reputation of Taekwondo, the scale of Kukkiwon leaves a big supply problem. This study therefore suggests the plan to design Taekwondo park that playa major role of Taekwondo development in the 21st century and represent the cultural heartland of Taekwondo. The study considers four points. The points are as follows: 1) Necessary programs drawn by analyzing and assessing Muju city as a site for Taekwondo park, then a survey conducted for potential visitors to a Taekwondo park. Under the theme of "A World Cultural Heritage Upon Our Own Lives", the park plan intends to become a shrine of Taekwondo as well as a big tourist attraction. 2) Programs are appropriate for the terms of the investment under the auspices of government, by considering potential visits and the site conditions. 3) The meaning of Taekwondo and its history should be reflected in the space distribution and facilities allotment. Three meaningful zones: symbolic zone, training zone and culture zone are considered in planning program and space distribution. 4) The plan also intends to harmonize with local development by groping Muju city's uplifting, not only designs a Taekwondo park.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.453-457
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• 2009

In this paper, plastic deformation behaviors of ESW105 and SCM435 steels are revealed by simulations and experiments. ESW105 is the special pre-heat-treated steel characterized by high initial yield strength and negligible strain-hardening behavior. The flow stresses of the two steels for large stain are calculated from tensile tests. Axial and lateral compressions of cylindrical bars are tested and simulated and the deformed shapes are compared to characterize the plastic deformation behaviors of the two materials. A forward extrusion process of a cylindrical bar is also simulated to reveal the difference. It has been shown that there are pretty much difference in plastic flow between ESW105 and SCM435 which causes from the difference in strain-hardening capability, implying that the experience-oriented design rules for common commercial materials may lead to failure in process design when the new material of ESW105 is applied without consideration of its plastic deformation behavior.

• Transactions of Materials Processing
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• v.16 no.3 s.93
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• pp.187-192
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• 2007

The finite volume method for forging simulation is examined to reveal its possibility as well as its problem in this paper. For this study, the finite volume method based MSC/SuperForge and the finite element method based AFDEX are employed. The simulated results of the homogeneous compression obtained by the two softwares are compared to indicate the problems of the finite volume method while several application examples are given to show the possibility of the finite volume method fur simulation of complex hot forging processes. It is shown that the finite volume method can not predict the exact solution of the homogeneous compression especially in terms of forming load and deformed shape but that it is helpful to simulate very complex forging processes which can hardly be simulated by the conventional finite element method.