• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.77-96
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• 1993

This in vitro study was undertaken to observe whether citric acid application aids the attachment and proliferation of human periodontal ligament cells to the root surfaces of periodontally diseased teeth. The roots were prepared so that the comparison could be made among the control healthy root surface, citric acid demineralized and non-demineralized root planted surfaces. Prior to the cell attachment experiment, each groups were prepared for scanning electron microscopic (SEM) examinations of root surface morphology, All specimens were fixed with phosphate buffered glutaraldehydes, postfixed with phosphate buffered osmium tetraoxide and stained with phosphate buffered tannic acid. dehydrated in ethanol, critical point dried, sputter coated with gold and examined under the SEM. In the cell attachement experiment, human cultured periodontal ligament cells at concentration to $4.5{\times}\;10^4\;cells/ml$ were seeded in each culture well which contained prepared roots and incubated for 30min 1, 2, 6, 12 and 24 hours at 37, 5% $CO_2$air incubator. Than the specimens were prepared for SEM examination using, the same methods as described above. In the cell proliferation experiment, $5{\times}\;10^4\;cells/ml$ cells were seeded incubated with the specimens for 6 hours. Then, all of the specimens were moved into fresh culture well and incubated for 24, 48, and 72 hours. The cell counting was done after trypsinization, under light microscope. The results were as follows. When viewed the surface morphology prior to the cell attachment, the non acid treated root planed surface displayed scaling striation and occasional bacteria and calculus. The citric acid treated specimens displayed little debris on the surface and funnel shaped orifices of dentinal tubules. There were no apparent differences in the morphology of cells attached to the control and experiment groups. However, in initial attachement, there was a slight more enhanced appearance in attachment in citric acid treated groups than other root surfaces. After 6 hours of incubation, most of the cells initiated the alteration of cell morphology from ovoid to spindle shapes. After 24 hours of incubation, most of the cells displayed proliferated appearance and connected with each other via numerous processes. In the cell proliferation experiments, there were statistically significant increased number of cells in citic acid treated groups than other groups.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.1-17
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• 1997

The purpose of this study was to investigate the aspects of proliferation and bone nodule formation of osteogenic precursor cells. To determine the effects of ascorbic acid and dexamethasone upon capacity of osteoblast proliferation and bone nodule formation, cells were maintained in the presence of one or some of these additives for up to 30 days. Group I culture was maintained in standard medium(DMEM plus 10% plus antibiotics), group II was maintained in supplemented medium containing dexamethasone, group III was maintained in supplemented medium containing ascorbic acid and sodium-${\beta}$-glycerophosphate, and group IV was maintained in supplemented containing ascorbic acid, sodium-${\beta}$-glycerophosphate and dexamethasone. Morphology of bone nodules was observed with light microscope and electron microscope. The results were as follows: ${\bullet}$ Proliferation capacity of osteoblasts was not affected by single use of dexamethasone, but it was chiefly affected by ascorbic acid. ${\bullet}$ Cellular morphology was fibroblastic appearance initially, but, it was gradually changed to polygonal shape accompanied by confluency stage. ${\bullet}$ Pluripotent mesenchymal cells existed during primary culture, they were differentiated to adipocyte, chondrocyte, osteocyte according to culture condition. ${\bullet}$ Dexamethasone increased bone nodule formation under the condition that the culture was maintained with supplemented medium ascorbic acid and sodium-${\beta}$-glycerophosphate. ${\bullet}$ when the cultures were stained with alizarin red, the group supplemented with dexamethasone, ascorbic acid and sodium-${\beta}$-glycerophosphate showed the marked increase of bone nodule formation, but the group supplemented with ascorbic acid and sodium-${\beta}$-glycerophosphate revealed only small amounts of bone nodules. And the groups cultured without ascorbic acid showed no observed any of bone-like mass independent of dexamethasone addition.

• Journal of The Korean Association For Science Education
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• v.23 no.3
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• pp.286-298
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• 2003

The purpose of this study was to analyze scientific thinking types and processes generated in inductive inquiry by college students. Subjects were three college student. Three inductive tasks were developed: Caminalcules set I which is a task consisted of 6 imaginary animals, a potato task which is a task about the interaction between juiced potato and $H_2O_2$, and Caminalcules set 2. Subjects' thinking types and processes were investigated through thinking-aloud method and interview. Subjects' performances were recorded on videotapes and analyzed. Subjects have shown 5 types of inductive thinking in the first task; observing, discovering commonness, discovering pattern, classifying, discovering hierarchy. The processes of inductive thinking shown by students are followed; observing $\rightarrow$discovering commonness $\rightarrow$classifying $\rightarrow$discovering pattern $\rightarrow$discovering hierachy. The subtypes of inductive thinking on observing were investigated by the analysis of subjects' performance on the second task. In analysis of protocol, student' thinking types on observing have been classified as simple observing and operational observing. Operational observing has been categorized conjectural observing and predictive observing. The subtypes of inductive thinking on classification and hierarchy were investigated by the analysis of subjects' performance on the third task. In analysis of protocol, students' thinking types on classification have been searching criteria for classifying and selecting criteria for classifying. Subtypes of discovering hierarchy have been classifying groups and hierarchical ordering by students. Processes of classifying groups proceeded from searching criteria for classifying to selecting criteria for classifying.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.613-622
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• 1996

Constrictive bronchiolitis, one of small airway diseases, is very rare and occupies one of the two arms of bronchiolitis obliterans together with proliferative bronchiolitis. Proliferative bronchiolitis, presenting the prototype with bronchiolitis obliterans with organizing pneumonia(BOOP), can be easily taken into diagnostic consideration in terms of relatively rapid clinical course and radiologic presentation as if atypical pneumonia with interstitial and alveolar infiltrations. Meanwhile constrictive bronchiolitis is not only very Tare but also easily overlooked as chronic obstructive pulmonary diseases such as emphysema, because it usually shows normal chest radiographic finding and obstructive pattern in pulmonary function test. In the aspects of the response to treatment, proliferative bronchiolitis showed dramatic response to the corticosteroid while constrictive bronchiolitis is intractable, which is easily explained on the basis of the pathologic characteristics of cicartrical replacement of bronchiolar walls. The bronchiolitis, both proliferative and constrictive, can be associated with diverse conditions such as inhalational injury, postinfectious process, drug of chemical induced reactions, connective tissue diseases, and organ trasplantation. And there is idiopathic type which has no associated condition. There is one explanation that both types of bronchiolitis lie on the same disease spectrum because the different disease pattern can be evoked from the same etiology. In contrast, another explanation is suggested that both types of bronchiolitis are one of nonspecific tissue reaction rather than a disease specific histologic finding because the various types of causes can provoke the same histologic findings. These dilemma remains for further investigation. With literature investigation, the authors report a case of constrictive bronchiolitis proven by open lung biopsy in 47 year old female who was diagnosed as non-Hodgkin's lymphoma and simultaneously had relatively rapid progression of airflow obstruction and showed negative radiographic finding without the rise factors for the development of chronic obstructive lung disease. We consider it as idiopathic because we could not find any relationship between constrictive bronchiolitis and non-Hodgkin's lymphoma on the literature search and it requires further investigation.

• The korean journal of orthodontics
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• v.31 no.6 s.89
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• pp.589-600
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• 2001

Insulin-like growth factor I (IGF-I) has the local tissue regulating actions. In bone, IGF-I increases the replication of osteoblastic lineage, probably preosteoblasts, and enhances osteoblastic collagen synthesis and matrix composition rates. The purpose of this study was to investigate the local regulatory effect of IGF-I on periodontium totally, both in an autocrine and paracrine manner. To examine the effect of IGF-I directly on osteoblast (OB) of test rats, and indirectlv on OB via periodontal ligament fibroblast (PDLF), and the effect of gingival fibroblast (GF) on OB via cellular paracrine manner for the understanding of humoral action of adjacent tissue, GF and PDLF were obtained from male Sprague-Dawley rats of six to eight weeks of age. OB was obtained iron frontal and parietal calvarial bone of Sprague-Dawley 21day-old-fetus. After each tell was Incubated 24 hours, for collecting conditioned medium, different concentrations of IGF-I (1,10,100 ng/ml,1ml/well) was adding in the GF, PDLF cells, and the supernatant from these cultures was put into the primary OB culture with $1{\times}10^4$cell/ml/well. The experimental group was divided into six groups control OB, IGF-I treated OB, OB culture with conditioned medium from PDLF, OB culture with conditioned medium from IGF-I treated PDLF, OB culture with conditioned medium from GF, OB culture with conditioned medium from IGF-I treated GF. After final IGF-I treatment, OB was Incubated for 24 hours, and alkaline phosphatase activity assay, BMP expression, cell proliferation measurement using MTT assay, total protein measurement, Collagen synthesis assay using western blot, and examination of bone nodule synthesis were done. Alkaline phosphatase expressions were increased in the group of PDLF-IGF-I supernatant treatment. Direct IGF-I treatment with concentrations of 100ng/m1 showed increased viable tell number measured by MTT assay. And IGF-I treatment did not increase total protein amount. The entire experimental group showed BMP2, 4 expression in western blot, and there was no significant difference between control and experimental groups. These results suggested that supernatant from PDLF effects on increasing cellular activities of OB regardless of IGF-I, and at high concentration, IGF-I increases OB tell proliferation.

• 대한공업교육학회지
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• v.40 no.1
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• pp.1-22
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• 2015

The purpose of this study was to select and organize educational contents needed to achieve systematic education of Invention intellectual property in secondary vocational education and ultimately to provide basic data for development of national-level curriculum. For this, the study, based on literature research, selected and organized educational contents of Invention intellectual property and learning elements in secondary vocational education, which served as the first draft. Then, the study verified its validity through experts' meeting and prepared its final draft. The experts' meeting comprized three teachers engaged in education of Invention intellectual property, two researchers (including a professor) and one person in charge of intellectual property. This study had following findings. First, the first draft of selection and organization of educational contents of Invention intellectual property in secondary vocational education as per the literature research suggested nine subject and 39 educational contents. The result of validity analysis for the suggested first draft turned out to be generally valid at 4.4 on average. Opinions modified and added by the experts' meeting were 30 in total with 5 altered, 20 modified and 5 added. Second, the result of validity analysis of learning elements in educational contents by the subject turned out to be generally valid. Average validity by the subject was revealed as Basics of invention 4.4, General invention/patent 4.5, Invention & problem solving 4.3, General intellectual property 4.5, Invention & design 4.6, Particulars of patents 4.4, Patent drawings 4.5, Patent & own business 4.5. Third, the final draft of educational contents of Invention intellectual property in secondary vocational education selected and organized eight subjects and 40 educational contents. The finally-suggested subjects included Basics of invention, General invention/patent, Invention & problem solving, General intellectual property, Invention & design, Particulars of patents, Patent information, Patent & own business.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1282-1286
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• 2006

Purpose : The causes of prolonged fever have changed during the years and are influenced by age, geographic location and availability of diagnostic facilities/techniques. The aim of the present study was to determine the causes of prolonged fever, to know the proportion and outcomes of undiagnosed children. Methods : We reviewed patients with fever persisting for more than 2 weeks in duration, with documented temperatures of $38^{\circ}C$ on several occasions, or uncertain diagnosis after intensive study of 1 week duration in other hospitals who were admitted to Pusan National University Hospital during the period from July 1999 to June 2004. Results : Fifty-four (59.0 percent) were boys and thirty-seven (41 percent) were girls. Forty-six cases were less than 6 years and 45 cases were more than 6 years; the mean age was $6.48{\pm}6.56years$. In 62 cases (68.1 percent), the fever had persisted for 2 to 3 weeks before admission and in 26 cases (28.6 percent), had lasted longer than a month. Final diagnosis had been reached in 66 of 91 children (72.5 percent). The most common cause was infection (38/91), followed by collagen vascular disease (12/91), immune deficiency (3/91), neoplasia (2/91), and miscellaneous disease. Tuberculosis was the most common infectious cause. The causes of fever were not revealed in 25 cases. Outcome on discharge were as follows; 77 cases (84.6 percent) were improved, 10 cases (11.0 percent) discharged without improvement and 4 cases (4.4 percent) expired. Conclusion : The most common cause of prolonged fever in Korean children remains infection, but the incidence of infection was decreased as compared with previous studies. Tuberculosis is the most common among infectious causes. As Kikuchi disease (subacute necrotizing lymphadenitis) represented a significant cause of prolonged fever, it should be considered if a patient has neutropenia with lymphadenopathy. Undiagnosed patients with prolonged fever (27.5 percent) have increased over previous studies.

• Biomedical Science Letters
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• v.2 no.1
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• pp.71-90
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• 1996

There is considerable current interest in the effect of regular vigorous exercise and in particular endurance-running as a possible measure in improving myocardial function. Some data indicate that the aging heart may actually suffer from vigorous endurance exercise. On the contrary appropriate exercise in aged animals improves myocardial function and aerobic energy metabolism. So far there is relatively little data to indicate that endurance exercise is in fact beneficial in improving myocardial function or damaging to heart of aged animals. The present investigation aimed to study the possible effect of a long range treadmill training program on the heart in aging rats. Male rats aged 3, 10, and 20 months were divided at random into a control (sedentary) and an exercise group. The training group was exercised for 5 days a week on an automated treadmill for 20minutes at 18m/min over a period of 5 months. The exercise regimen of our experiments did not cause any significant changes in the tissues and ultrastructural as com-pared with sedentary age-matched control. Tissues and ultrastructures of myocardial cells in trained group aged 8 months are intact and well organized as well as sedentary control group. Age associated tissue and ultrastructural changes of trained group aged 15 months included : an increase in transformed mitochondria, vacuoles, lysosomes, lipid droplets and early lipofuscin. But the trained heart did not show significant difference in tissue and ultrastructural properties from those of sedentary controls. Endurance-trained group aged 25 months showed significant qualitative tissue and ultrastructural difference as compared with age-matched controls. In addition to those found in 25 months control group, focal necrosis, myofibril fraying, hypercontraction band, seperation of intercalated discs, degenerating nucleus and infiltration of collagenous fiber into myocyte were noted in trained 25 months group. The stereological examination of the mi-crographs disclosed no significant difference in the myoflbril, mitochondrion, sarcotubule and in-terstitium volume density and surface density of mitochondrial cristae and numerical density of mitochondria between trained and control group aged 8 and 15 months. In the trained 25 months group, significant increase in volume density of interstitium, lipofucsin granule were shown as compared to untrained age-matched control. On the other hand, significant decrease in mitochondrion volume density was shown. The myofibril volume density did not differ between trained and control group although trained group showed slight increase. From the data obtained a reduced mitochondria/myofibrils ratio was found in trained rat heart aged 25 months and there was no difference between trained and control rat aged 15 months. But a slight but not significant increase was found in the trained group aged 8 months as compared with same age control group. Such increase in the ratio in young animals is considered to be of great importance to cardiac pumping and adaptability. Whereas such adaptations don't seem to occur in aged heart muscle. This study proposed that repeated endurance exercise do not cause any significant qualitative and quantitative ultrastructural change of heart muscle in young(3months) and adult (10months) suggesting that the heart is able to adapt to the exercise. On the contrary, the repeated endurance exercise stress may actually induce degenerative changes in the aged heart muscle(20months).

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.41-50
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• 2008

The histochemical characteristics and ultrastructure of the mantle in the spiny top shell, Batillus cornutus were described using light and electron microscopy. The simple epidermal layer wrapped on the top and bottom of the centrally located connective tissue. And then the epidermal layer were divided into the outer epidermal layer near a shell and the inner epidermal layer closed to the visceral mass. The connective tissue layer was composed of the collagen fiber muscularfiber bundle and hemolymph sinus. Mucous cells in the apical mantle contained acid and neutral mucopolysaccaride, and acidic carboxylated mucopolysaccaride in the mid and marginal mantle. The mantle thickness, epidermal layer thickness and hemolymph sinus area displayed a trend of reduction from the marginal zone to the apical zone. From TEM observation, it was possible to distinguish epithelium, ciliated cell, absorptive cell and secretory cell in the epidermal layer. The epithelia were columnar and the nucleus was elliptical. The free surface were covered with microvilli. The lateral membranes of epithelium was con nected with neighboring cells by the zonular occludens, zonular adherens and membrane interdigitation. Ciliated cell on free surface had cilia and microvilli, and numerous mitochondria in the apical cytoplasm. In the epidermal layer, it observed 2 type cells having absorptive function. The absorptive cells were columnar in shape, and contained microvilli, pinocytotic vesicles, mitochondria and lysosomes of various electron density. Secretory cells can be divided into four types (A, B, C, D) depending on the cell shape and characteristics of secretory granules. These cells were unicellular glands and had similar characteristics to previously reported on the mantle of the gastropod and bivalves.

• Journal of Yeungnam Medical Science
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• v.11 no.2
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• pp.230-239
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• 1994

In Order to evaluate determinants of successful percutaneous transluminal coronary angioplasty (PTCA), PTCA was performed for 172 coronary arterial lesions in 120 patients (89 male, 31 female) at Yeungnam university hospital from Sep. 1992 to Aug. 1993. The corinary artery luminal diameter at the site of the original stenosis was eveluated from end-diastolic frames of identical projections of the preangioplasty and immediate post angioplasty. The coronary luminal and balloon diameters were measured with using of computer measuring system. Overall success rate of 172 attempted lesions was 87.2%. Success rate of female patients was 93.5% and higher than those of male patients. According to the clinical diagnosis, success rate in stable angina was 93.7% and higher than those of post myocardial infarction angina, unstable angina and acute myocardial infarcrion. Success rate of American Heart Association type C lesion was 65.5% and lower those of type A (95.7%), type B (89.5%). There was signfifcantly difference in preangioplasty luminal stenosis, elastic recoil and length of lesion between successful PTCA group and failed PTCA group. Success rate of lesion location at a bend > $45^{\circ}$ and presence of intracoronary thrombus were lower than than those of other angiographic findings. In coclusion, primary angioplasty success was affected by specific angiographic factors. Stenosis severity, thrombus, lesion location at a bend > $45^{\circ}$, elastic recoil, and length of lesion were the principle of determinants of coronary angioplasty success rate.