• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.1
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• pp.36-48
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• 2008

To repair bone defects in the oral and maxillofacial field, bone grafts including autografts, allografts, and artificial bone are used in clinical dentistry despite several disadvantages. The purpose of this study was to evaluate new bone formation and healing in rat calvarial bone defects using hydroxyapatite (HA, $Ca_{10}[PO_4]_6[OH]_2,\;Bongros^{(R)}$, Bio@ Co., KOREA) and tricalcium phosphate (${\beta}-TCP,\;Ca_3[PO_4]_2$, Sigma-Aldrich Co., USA) mixed at various ratios. Additionally, this study evaluated the effects of type I collagen (Rat tail, BD Biosciences Co., Sweden) as a basement membrane organic matrix. A total of twenty, 8-week-old, male Sprague-Dawley rats, weighing 250-300g, were divided equally into a control group (n=2) and nine experimental groups (n=2, each). Bilateral, standardized transosseous circular calvarial defects, 5.0 mm in diameter, were created. In each experimental group, the defect was filled with HA and TCP at a ratio of 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 0:100 with or without type I collagen. Rats were sacrificed 4 and 8 weeks post-operation for radiographic (standardized plain film, Kodak Co., USA), histomorphologic (H&E [Hematoxylin and Eosin], MT [Masson Trichrome]), immunohistochemical staining (for BMP-2, -4, VEGF, and vWF), and elementary analysis (Atomic absorption spectrophotometer, Perkin Elmer AAnalyst $100^{(R)}$). As the HA proportion increased, denser radiopacity was seen in most groups at 4 and 8 weeks. In general radiopacity in type I collagen groups was greater than the non-collagen groups, especially in the 100% HA group at 8 weeks. No new bone formation was seen in calvarial defects in any group at 4 weeks. Bridging bone formation from the defect margin was marked at 8 weeks in most type I collagen groups. Although immunohistochemical findings with BMP-2, -4, and VEGF were not significantly different, marked vWF immunoreactivity was present. vWF staining was especially strong in endothelial cells in newly formed bone margins in the 100:0, 80:20, and 70:30 ratio type I collagen groups at 8 weeks. The calcium compositions from the elementary analysis were not statistically significant. Many types of artificial bone have been used as bone graft materials, but most of them can only be applied as an inorganic material. This study confirmed improved bony regeneration by adding organic type I collagen to inorganic HA and TCP mixtures. Therefore, these new artificial bone graft materials, which are under strict storage and distribution systems, will be suggested to be available to clinical dentistry demands.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1001-1008
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• 1996

Staphylococcal food poisoning is the major cause of bacterial food poisoning occurring in this country. Therefore government regulates commercial foods through Official Dictionary of Food that there should be free of enterotoxigenic Staphylococcus aureus in Korean rice cakes, bread, and a box lunch. Since at least 5 days are required to identify the S. aureus by the official method in the Dictionary it is difficult to prevent the food poisoning and the investigation of the outbreaks. In this report an improved determination method of the S. aureus has been developed using polymerase chain reaction (PCR) technique. Sense and antisense primers for specific amplification of genes encoding staphylococcal enterotoxins were designed and synthesized for the PCR. Rapid chromosomal DNA isolation method was also developed from S. aureus using lysostaphin. The PCR condition was developed as follows. Reaction solution $(50\;{\mu}l)$ consisted of target DNA $2\;{\mu}l$ (about 20ng), 10X buffer $5\;{\mu}l$, primer 100pmole, dNTP (10 mM) $4\;{\mu}l$ and Taq DNA polymerase 2.5 unit in a thin-wall tube. Operation condition of the PCR was 5 min pre-denaturation at $94^{\circ}C$, 15 sec denaturation at $94^{\circ}C$, 15 sec annealing at $50^{\circ}C$, 20 sec extension at $72^{\circ}C$, and 5 min post-extension at $72^{\circ}C$, and 30 cycles of denaturation-annealing- extension. Using the PCR with Perkin Elmer GeneAmp PCR system 2400, types of enterotoxigenic S. aureus could be identified from Ddok or bread in a day.

• Journal of Digital Convergence
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• v.18 no.8
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• pp.55-67
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• 2020

The purpose of this study was to investigate the effects of CELL curriculum participation on learning flow, learning motivation, academic self-efficacy, and self-directed learning ability. To this end, in the first semester of 2020, 386 students from K University conducted a pre-post survey and analyzed using SPSS. The main research results are as follows. First, participation in the CELL curriculum showed statistically significant improvement in the student's learning flow, learning motivation, academic self-efficacy, and self-directed learning ability. Second, the analysis by gender showed significant improvement in learning flow, academic self-efficacy, and self-directed learning ability only for female students. Third, in the analysis by grade level, the sophomore showed significant improvement in learning flow and self-directed learning ability, the junior in all variables, and the senior in academic self-efficacy and self-directed learning ability. Fourth, participation impressions and improvements were summarized through interviews of participating students. This study is significant in that it examines the effectiveness of the CELL curriculum and suggests practical measures for systematic operation and support.

• Journal of Technologic Dentistry
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• v.37 no.3
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• pp.131-144
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• 2015

Purpose: This study set out to propose plans for more efficient and effective clinical practice by investigating the current state of clinical practice in the field of dental technology and thus provide basic data to develop pre- and post-education programs for clinical practice. Methods: The subjects include dental technicians at dental technical laboratories that were appointed as the place of clinical practice by the Department of Dental Technology of G University. The survey period spanned from December 22, 2014 to January 20, 2015. Total 250 questionnaires were distributed to them, and 190(76.0%) were returned. After excluding 23 whose answers were uncertain or seemed to lack reliability, total 167(66.8%) were used in final analysis. Results: 1. The most frequent practice the student did during clinical practice was articulator attachment, which was followed by pin operation or model making, one's own task and practice, sand and crow sculpturing, burying, casting, and grinding. 2. In case of going through the entire process, porcelain had the most students at 39(23.4%), being followed by crown & bridge at 28(16.8%), clinical model at 23(13.8%), full denture at 17(10.2%), and partial denture at 17(10.2%) in the order. 3. Of the students, 59.8%(30.5% for reinforced basic practice; 29.3% for intensive practice education) said that intensive practice education should be reinforced in school; and 22.3% said that intensive theory and practice education was needed, which indicates that 82.6% voiced their opinion of reinforcing education around practice. 4. The students felt that they lacked diligence, passion, and theoretical knowledge somewhat and were relatively good at clinical adaptation and operational skills. Conclusion: The findings show that the students felt an absolute lack of practice education as the school education was focused on theory and national exams in the field of dental technology, thus raising a need to reinforce practice education. Of all the respondents, 62.9% said there was a need to improve the current education with a focus on jobs. In future, education of dental technology should work to bring up able dental technicians that can perform in clinical dental technology right after graduation by reinforcing job-based practice education.

• Journal of Gastric Cancer
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• v.6 no.1
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• pp.47-51
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• 2006

The origin of a submucosal tumor is difficult to determine by endoscopic biopsy. One type of submucosal tumor, which originates in Schwann cell, a schwannoma represents 0.2% of all gastric tumors. We experienced the case of a 57-year-old female patient with a gastric schwannoma presenting with melena and anemia. Computed tomography and upper gastrointestinal endoscopy showed a protruded huge mass from 3 cm below the cardia to angle. Seven endoscopic biopsies indicated only necrotic debri and granulation tissue, chronic gastritis. Because we suspected an advanced gastric cancer, or lymphoma with bleeding, It was performed an operation for an exact diagnosis and a treatment for bleeding. A-post-operative histopathological, immunohistochemical examination led to the final diagnosis of a gastric schwannoma.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.455-458
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• 2013

The conventional design of the information system architecture based on the personal experience of information systems has been acted as a limit in progress utilizing appropriate resource allocation and performance improvements. Architecture design depending on personal experience makes differences in variance of a designer's experience, intellectual level in related tasks and surroundings, and architecture quality according to individual's propensity. After all these problems cause a waste of expensive hardware resources. At working place, post-monitoring tools are diversely developed and are running to find the bottleneck and the process problems in the information operation. However, there are no simulation tools or models that are used for expecting and counteracting the problems at early period of designing architecture. To solve these problems we will first develop a simulation model for designing information system architecture in a pilot form, and will verify validity. If an error rate is found in the permissible range, then it can be said that the simulation reflects the characteristic of information system architecture. After the model is developed in a level that can be used in various ways, more accurate performance computation will be able to do, getting out of the old way relying on calculations, and prevent the existence of idle resources and expense waste that comes from the wrong design of architecture.

• Journal of Environmental Health Sciences
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• v.40 no.5
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• pp.331-345
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• 2014

Objectives: The exponential growth of chemicals, an area of high concern in developed countries like the US (i.e., the Gore Initiative) and in the EU (i.e., REACH), as well as recent chemical accidents in Korea, have provoked nationwide concerns and resultant legal enforcement. This study aims to compare the laws of the Ministry of Environment (the Chemical Substances Control Act (CSCA), Act on the Registration and Evaluation, etc. of Chemical Substances (ARECS)) with those of the Ministry of the Employment and Labor (Occupational Safety and Health Act (OSHA)). Methods: Each law pertaining to the Ministry of Environment and the Ministry of the Employment and Labor was downloaded from the official legal information system (www.law.go.kr). The objectives of each law and the major contents related to chemical management were compared and summarized. Results: The CSCA and the ARECS are focused on the protection of people and the environment, while the OSHA relates to the protection of workers. The right to know of people and workers has been reinforced. The former two laws emphasize prevention, but the OSHA contains both preventive and post-accident measures. The role of the Ministry of Employment was reinforced with the promulgation of the CSCA and ARECS, which contain regulations such as adjacent area impact evaluation, risk control planning, chemical statistical survey and construction and operation of information, provision of risk control plans, response to chemical accidents and registration of chemical substances. Conclusion: We found that the three laws discussed here have several similar clauses designed to protect people and the environment from risks that may be caused by the use of chemicals, even though there are some differences among them in terms of objectives and contents. This review concluded that several clauses that can be regarded as double regulation should be unified in order to minimize the waste of government administrative resources and socio-economic losses.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.76-76
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• 1993

Endotracheal intubation is common technique for general anesthesia or patency of airway. However, laryngeal intubation granuloma is the most common sequale of endotracheal intubation in otolaryngologic field. From 1982 to 1992, the authors had experienced 16 cases intubation granuloma. The following results were as follows; 1. Age distribution was mostly in the 20 to 49 years old group (84 %).The sex ratio of male to female was 1:7, predominantly in female. 2. Main sx. were hoarse in 12(75%), F.B. sensation in 3(18%), dyspnea in 1 (6%). 3. The side of lesion was bilateral in 6 cases (37%) and unilateral in 10 cases (63%). Unilateral had the 3 cases (30%) in left and the 7 cases (70%) in right. The location of mass was vocal process of arytenoid cartilage in 8 cases(50%), post 1/3 of vocal cord in 6 cases (37 %) and middle 1/3 of vocal cord in 2 cases (12 %). 4. The duration between extubation and onset of symptom in less than a month was most frequent in 7 cases (44 %) out of 16 cases. 5. The most common operation was cesarean section in 6 cases (37 %). 6. Mean duration of intubation time was 2 hour 5 minutes. 7. Composition of used intubation tube was red rubber tube. 8. One case (6 %) was recurred.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.1
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• pp.16-29
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• 1991

The occurrence of thrombotic occlusion & endothelial injuries at the site of anastomosis have been considered as major problems in microvascular surgery. The purpose of this study was to ascertain whether a end-in-end(sleeve, telescope) anastomosis compared favorably with end-to-end anastomosis in healing procedures on the endothelium and to study the possibility of clinical application in end-in-end method. The microvascular anastomoses have been performed with end-in-end method in the femoral arteries of 20 rats group, also with end-to-end method on the same arteries of another 20 rats group, and then the four anastomosed vessels in subdivided groups on each group were taken after period of 1, 3, 7, 14, 21 days following by anastomoses for scanning electron microscope observation. The results were as following: 1. The patency rate was 90% in the end-in-end group and 85%in the end-to-end group and late thrombus occurred at 7, 14 days on both groups, which suggested -consistent monitoring of patency was required for two weeks at least. 2. Platelet aggregates at the site of anastomosis began to organize on post-operation 3 days and in the end-in-end group, the initially decreased lumen of inserted vessel was gradually increasing on 7 days due to atrophy of the medial layers. 3. Re-endothelialization was completed between 7 and 14 days in end-in-end group, whereas between 14 and 21 days in end-to-end group.

• Clean Technology
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• v.20 no.2
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• pp.179-188
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• 2014

The effect of desorption pressure on $CO_2/N_2$ breakthrough behaviors for 4 different adsorbents was studied at a fixed bed. Zeolite 3A, 4A, 5A, and 13X pellets were used as adsorbents. Cyclic operations were executed with varying desorption pressure from vacuum (0 bar) to 3 bar while other conditions such as adsorption step pressure (3 bar), temperature (293 K), composition ($CO_2:N_2=10:90$vol%) and flow rate (400 ccm) were fixed at constant values. Each adsorption and desorption step was set as 80 min, which totaled up to 160 min per a cycle. 5 cycles with adsorption and desorption steps were run overall. After the experiment, breakthrough time, saturation time, and adsorption amount were measured and compared in order to find an optimum adsorbent and a proper operating condition for a post combustion $CO_2$ capture process.