• Journal of the Korean Institute of Educational Facilities
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• v.19 no.3
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• pp.21-31
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• 2012

According to the decrease in birth rate and reduction of population in rural area, primary schools have brought about many problems for decrease of number of student, and environment of education have became deteriorated. Accordingly, primary schools be required improvement, and it should be altered placement of schools because it change number of student, distance and time of attending school, and formation of school zone are changed by alternating of human and physical environment. Merger and abolition of primary school is inevitable for change of placement standard to primary school and qualitative improvement of environment of education in rural area. This study suggests the effective space planning methods for unified school and appropriate utilization alternatives for closed school following after the merger and abolition of small rural schools. In doing so, it explores the present models of merger and abolition through analysis of all sort of actual condition and the possibilities for various utilizations of the abolished schools. It proposes a classroom-operation type fused the comprehensive class and departmental class system for merged primary schools in rural area. It also suggests the re-use methods of closed school facilities for students and community. Finally, it emphasizes that in order to success the policy of the merger and abolition of small schools, it be attributed to the social-cultural environment based on local residents and community and required provision of a variety of utilization plans reflecting local specifics and guarantee of local residents' participation and selection.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.1
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• pp.66-69
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• 2019

This study proposes a high-efficiency phase-shifted full-bridge (PSFB) converter with a wide input voltage range. The conventional PSFB converter is a useful topology in high-power applications. This converter not only achieves the zero-voltage switching of the primary switches, but also has small RMS current in the primary side. However, because the conventional PSFB converter has large freewheeling current in the primary side when it is designed considering the hold-up time of the converter, such a converter has high conduction loss at the primary switches. To solve this problem, a new PSFB converter is proposed in this study. The experiment is implemented with an input voltage ranging from a 320 V-400 V and an output power specification of 715 W.

• The Korean Journal of Cytopathology
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• v.15 no.2
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• pp.112-115
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• 2004

Lymphoproliferative disorders, manifesting either as a primary lesion or as part of a generalized process, rarely involve the breast. The primary malignant lymphoma of the breast is rare. The cytologic features of this neoplasm have not been reported in Korea thus far. We described a case of primary malignant lymphoma of the breast, as diagnosed by fine needle aspiration cytology (FNAC) in an 84-year-old female. FNAC smears showed high cellularity. The main cytologic feature observed was a carpeting of monotonous, atypical, enlarged lymphoid cells. These lymphocytes showed relatively round elliptical nuclei with some indentation. One or more prominent nucleoli were seen. Biopy from the breast mass revealed diagnostic features of non-Hodgkin's lymphoma, diffuse large B-cell type.

• Journal of Ginseng Research
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• v.37 no.4
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• pp.401-412
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• 2013

Korean Red Ginseng (KRG) is an oriental herbal preparation obtained from Panax ginseng Meyer (Araliaceae). To expand our understanding of the action of KRG on central nervous system (CNS) function, we examined the effects of KRG on tissue plasminogen activator (tPA)/plasminogen activator inhibitor-1 (PAI-1) expression in rat primary astrocytes. KRG extract was treated in cultured rat primary astrocytes and neuron in a concentration range of 0.1 to 1.0 mg/mL and the expression of functional tPA/PAI-1 was examined by casein zymography, Western blot and reverse transcription-polymerase chain reaction. KRG extracts increased PAI-1 expression in rat primary astrocytes in a concentration dependent manner (0.1 to 1.0 mg/mL) without affecting the expression of tPA itself. Treatment of 1.0 mg/mL KRG increased PAI-1 protein expression in rat primary astrocytes to $319.3{\pm}65.9%$ as compared with control. The increased PAI-1 expression mediated the overall decrease in tPA activity in rat primary astrocytes. Due to the lack of PAI-1 expression in neuron, KRG did not affect tPA activity in neuron. KRG treatment induced a concentration dependent activation of PI3K, p38, ERK1/2, and JNK in rat primary astrocytes and treatment of PI3K or MAPK inhibitors such as LY294002, U0126, SB203580, and SP600125 (10 ${\mu}M$ each), significantly inhibited 1.0 mg/mL KRG-induced expression of PAI-1 and down-regulation of tPA activity in rat primary astrocytes. Furthermore, compound K but not other ginsenosides such as Rb1 and Rg1 induced PAI-1 expression. KRG-induced up-regulation of PAI-1 in astrocytes may play important role in the regulation of overall tPA activity in brain, which might underlie some of the beneficial effects of KRG on CNS such as neuroprotection in ischemia and brain damaging condition as well as prevention or recovery from addiction.

• Journal of the Korean School Mathematics Society
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• v.18 no.4
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• pp.353-370
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• 2015

This study was conducted as a qualitative case study that explored how gifted 3rd-grade elementary school children who had learned the primary concepts of division and fraction, when they studied contents about decimal, formed the transformed primary concept and transformed schema of decimal by the learning of accurate primary concepts and connecting the concepts. That is, this study investigated how the subjects attained relational understanding of decimal based on the primary concepts of division and fraction, and how they formed a transformed primary concept based on the primary concept of decimal and carried out vertical mathematizing. According to the findings of this study, transformed primary concepts formed through the learning of accurate primary concepts, and schemas and transformed schemas built through the connection of the concepts played as crucial factors for the children's relational understanding of decimal and their vertical mathematizing.

• Journal of the Korean Society of School Health
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• v.14 no.2
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• pp.187-206
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• 2001

The study was carried out to estimate the prevalence and possible causes of refractive errors in primary school children. At one primary school in urban Daegu, one in the medium-sized city of Yongcheon and 2 in rural areas, children wearing glasses and children with visual acuity of less than 0.7 were given our questions. 354 out of 378 children responded to our questions. The research was done from March 2000 to February 2001. The data were analyzed by percentage, x2 test, t-test, ANOVA and Scheff method. Children with eyesight problems were more prevalent in urban areas than rural areas. The lack of luminosity during reading (p=0.015), length of reading time (p=0.08) and posture which watching TV (p=0.023) appeared leading causes of progressing myopias. The visual impairment caused by refractive errors may affect the mental and physical activity of primary school children and lead to social isolation, loneliness and depression. However, little attention may be paid by professionals engaged in providing health care to the children. Once we have recognized the impact of visual impairment, we may be in a better position to prevent progressing refractive errors.

• Tuberculosis and Respiratory Diseases
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• v.69 no.6
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• pp.465-468
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• 2010

Spontaneous pneumothorax (SPTx) associated with primary lung cancer is quite rare, but has been reported as the initial presentation or a complication of disease progression. Moreover, chemotherapy-related SPTx in primary lung cancer occurs at a very low frequency, accounting for less than 0.05% of all cases. Here, we report the first case of erlotinib-related SPTx in a patient with advanced lung adenocarcinoma in Korea. After 3 cycles of cisplatin-based chemotherapy as first-line therapy, erlotinib was administered as second-line treatment. Asymptomatic SPTx accompanied by a significant decrease in tumor size was observed in the left lung 7 weeks later. The patient received continuous administration of erlotinib, without additional treatment. This case showed that SPTx can occur in patients with primary lung cancer receiving erlotinib, and asymptomatic chemotherapy-related SPTx in primary lung cancer may not require therapeutic intervention.

• International Journal of Oral Biology
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• v.32 no.1
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• pp.13-22
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• 2007

The stem cell research is emerging as a cutting edge topic for a new treatment for many chronic diseases. Recently, dental stem cell would be possible for regeneration of tooth itself as well as periodontal tissue. However, the study of the cell characterization is scarce. Therefore, we performed the genetic profiling and the characterization of mouse fetus/neonate derived dental tissue and cell to find the identification during dental development. We separated dental arch from mandibles of 14.5 d fetal mice and neonate 0 d under the stereoscope, and isolated dental cells primarily from the tissues. Then, we examined morphology and the gene expression profiles of the primary cells and dental tissues from fetus/neonate and adult with RT-PCR. Primary dental cells showed heterogeneous but the majority was shown as fibroblast-like morphology. The change of population doubling time levels (PDLs) showed that the primary dental cells have growth potential and could be expanded under our culture conditions without reduction of growth rate. Immunocytochemical and flow cytometric analyses were performed to characterize the primary dental cell populations from both of fetus (E14.5) and neonate. Alpha smooth muscle actin (${\alpha}-SMA$), vimentin, and von Willebrand factor showed strong expression, but desmin positive cells were not detected in the primary dental cells. Most of the markers were not uniformly expressed, but found in subsets of cells, indicating that the primary dental cell population is heterogeneous, and characteristics of the populations were changed during culture period. And mesenchymal stem cell markers were highly expressed. Gene expression profile showed Wnt family and its related signaling molecules, growth factors, transcription factors and tooth specific molecules were expressed both fetal and neonatal tissue. The tooth specific genes (enamelin, amelogenin, and DSPP) only expressed in neonate and adult stage. These expression patterns appeared same as primary fetal and neonatal cells. In this study we isolated primary cells from whole mandible of fetal and neonatal mice. And we investigated the characteristics of the primary cells and the profile of gene expressions, which are involved in epithelial-mesenchymal interactions during tooth development. Taken together, the primary dental cells in early passages or fetal and neonatal mandibles could be useful stem cell resources.

• Journal of Chest Surgery
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• v.45 no.5
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• pp.330-333
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• 2012

Aortoenteric fistula is a rare but potentially fatal condition causing massive gastrointestinal bleeding. In particular, double primary aortoenteric fistulae are vanishingly rare. We encountered a 75-year-old male patient suffering from abdominal pain, hematochezia, hematemesis, and hypotension. His computed tomography images showed abdominal aortic aneurysm and suspected aortoenteric fistulae. During surgery, we found two primary aortoenteric fistulae. The one fistula was detected between the abdominal aorta and the third portion of the duodenum, and the other fistula was detected between the abdominal aorta and the sigmoid colon. We conducted the closure of the fistulae, the exclusion of the aneurysm, and axillo-bifemoral bypass with a polytetrafluoroethylene graft. The patient was discharged with no complications on the 21st postoperative day.

• Journal of the Korean association of regional geographers
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• v.8 no.4
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• pp.492-512
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• 2002

The daily life activities of primary school children have been increasingly diversified. This research examined the spatio-temporal characteristics of primary school children's daily life activities. The time allocation of primary school children's daily activities was monotonous. They tended to spend most of their time in school activities, private lessons after school, and studying at home. The daily trip to school has been diversified as the result the of increase in the number of double-income families, car owners, facilities for pastime, and educational facilities for private lessons after school. The selection of educational facilities for private lessons was strongly influenced by accessibility to the residence because of the limited time budget of primary school children and the controlled trip behavior by parents. The leisure activities were considered as a minor function and took place in the interval of performances of study-related activities. The high proportion of leisure activities was found in the indoor play. The amount of the time for leisure activity was very insufficient. The spatial range and time budget were strongly influenced by the institutional conditions of parents.