• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.658-665
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• 2007

Oligodontia is defined as the congenital absence of six or more teeth in dentition, excluding the third molars. The prevalence of congenital missing teeth is about 1.6 to 9.6% of population and the prevalence of oligidontia is about 0.08 to 1.1%. The mandibular second premolar is the most frequently absent after the third molar, followed by the maxillary lateral incisor and upper second premolar. Females seem to be affected slightly more than males. Oligodontia may occur either in isolation, or as a part of a syndrome such as ectodermal dysplasia. Different causes are possible for oligodontia: physical obstruction or distruction of the dental lamina, space limitation, functional abnormalities of the dental epithelium, failure of induction of the underlying mesenchyme, chemotherapy, radiotherapy or genetic factor. Because oligodontia would result in esthetic and functional problems, such as facial asymmetry or occlusal disharmony, early diagnosis from clinical and radiographic examination was necessary. And appropriate treatment plan should be followed. This case report was about oral conditions and treatment of the oligodontia patients who have no specific systemic disease.

• Journal of Chest Surgery
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• v.37 no.2
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• pp.113-118
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• 2004

The studies on cryopreserved arterial allograft have been focused on cooling methods, pre-treatment, cryoprotectant agents, and preservation temperature. But recently, several studies have reported that thawing methods also play an important role in the occurrence of macroscopic and microscopic cracks. This study was designed to investigate the cell injury after thawing, using a rabbit model to clarify the effect of thawing methods on cryopreserved arteries. Material and Method: Segments of the rabbit aorta were obtained and divided into 3 groups (n=60) according to whether the specimens were fresh (control, n=20), cryopreserved and rapidly thawed (RT) at 37$^{\circ}C$ (n=20), or cryopreserved and subjected to controlled, automated slow thawing (ST)(n=20). Cell damage was established using the TUNEL method and the morphological changes were also evaluated. Result: In the group that was rapidly thawed, the expression of TUNEL (＋) cells increased significantly more than in the slowly thawed group. In addition, the endothelial denudation, microvesicles and edema were significant in the rapidly thawed group compared with those changes in the slowly thawed group. Conclusion: Our study suggests that the rapid thawing method may be one of the major causes of cellular damage and delayed rupture in cryopresewed arterial allografts. The expression of TUNEL (＋) cells and structural changes were significantly low in the slowly thawed group, which might have contributed to the improvement of graft failure after transplantation.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.34-37
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• 2017

In recent emerging industry, Display field becomes bigger and bigger, and also semiconductor technology becomes high density integration. In Flat Panel Display, there is an issue that electrostatic phenomenon results in fine dust adsorption as electrostatic capacity increases due to bigger size. Destruction of high integrated circuit and pattern deterioration occur in semiconductor and this causes the problem of weakening of thermal resistance. In order to solve this sort of electrostatic failure in this process, Soft X-ray ionizer is mainly used. Soft X-ray Ionizer does not only generate electrical noise and minute particle but also is efficient to remove electrostatic as it has a wide range of ionization. X-ray Generating efficiency has an effect on soft X-ray Ionizer affects neutralizing performance. There exist variable factors such as type of anode, thickness, tube voltage etc., and it takes a lot of time and financial resource to find optimal performance by manufacturing with actual X-ray tube source. MCNPX (Monte Carlo N-Particle Extended) is used for simulation to solve this kind of problem, and optimum efficiency of X-ray generation is anticipated. In this study, X-ray generation efficiency was measured according to target material thickness using MCNPX under the conditions that tube voltage is 5 keV, 10 keV, 15 keV and the target Material is Tungsten(W), Gold(Au), Silver(Ag). At the result, Gold(Au) shows optimum efficiency. In Tube voltage 5 keV, optimal target thickness is $0.05{\mu}m$ and Largest energy of Light flux appears $2.22{\times}10^8$ x-ray flux. In Tube voltage 10 keV, optimal target Thickness is $0.18{\mu}m$ and Largest energy of Light flux appears $1.97{\times}10^9$ x-ray flux. In Tube voltage 15 keV, optimal target Thickness is $0.29{\mu}m$ and Largest energy of Light flux appears $4.59{\times}10^9$ x-ray flux.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.787-799
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• 2017

Although the long-term leakage between the box culvert and the soil contact surface is one of the main causes of the failure in the embankment of the reservoir, there is a little studies on this matter. If a leakage occurs by the structure such as the buried box culvert of reservoir embankment is partially damaged, it is difficult to observe and there is a possibility of damage caused by piping. For these reasons, more research is necessary. In this study, the embankment type of the reservoir is divided into the core type and the homogeneous type when the damaged box culvert passing through the embankment of the reservoir is leaked due to the differential behavior of materials like differential settlement. In view of the condition, the seepage analysis of 2D was performed according to the water level change. The result of the study shows that the possibility of piping increases at the upper part rather than the bottom part of the box culvert when the leakage occurs to the box culvert passing through the embankment of the reservoir. Particularly, it is considered that the presence of the core helps to maintain the seepage stability of the embankment in case where the leakage occurs at the downstream side of the embankment. Also, if there is a drastic decrease on the internal pore water pressure in the embankment of reservoir, it is necessary to consider the possibility of piping.

• Tuberculosis and Respiratory Diseases
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• v.57 no.1
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• pp.66-71
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• 2004

Primary pulmonary hypertension (PPH) is a rare, progressive and incurable disease, which is characterized by an increase in the pulmonary artery pressure without a demonstrable cause. The most common presenting symptom is dyspnea on exertion, with other symptoms comprising of chest pain, syncope and hemoptysis. The diagnosis is one of exclusion of any of the known causes of pulmonary hypertension. When associated with pregnancy, the maternal mortality ranges from 30 to 50%. Because pregnancy and labor are very serious problems for patients with PPH, the available evidence suggests that pregnancy when afflicted with PPH should be avoided. In account the case of a 33-year old patient, reporting with massive hemoptysis, and diagnosed with PPH during her twenty seventh week of gestation, is presented. She was treated with conservative management, including oxygen and a vasodilator, and underwent a pregnancy termination. However, due to aggravation of right heart failure, she presented with severe systemic hypotension and hypoxemia, and eventually died. This case is reported, with brief review of the literature.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1977.06a
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• pp.9.1-10
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• 1977

Many etiological factors playa significant role in the development of tracheal stenosis; too high tracheostomy (Jackson, 1921), too small stoma (Greisen, 1966), the treatment with respirator using cuffed tube (Pearson et al., 1968; Lindholm, 1966; Bryce, 1972) and infection (Pearson, 1968). Although the incidence has been reduced due to development of surgical technique and antibiotics, the frequency of tracheal stenosis which produces symptoms after tracheostomy ranges from 1.5 per cent (Lindholm, 1967). In the management of the stenosis, mild cases are treated by mechanical dilatation with silicon tube or stent (Schmigelow, 1929; Montgomery, 1965) combined steroid (Birck, 1970), and in the cases of stenosis causes, these removed under the are bronchoscopy. But in severe stenosis, transverse resection with subsequent end-to-end anastomosis has been used in recent years (Pearson et al., 1968). During about 10 years, 1967 to 1977, a total of 23 patients with tracheal stenosis complicated among the 1, 514 tracheostomies have been treated in Severance Hospital. Now, we have obtained following conclusions by means of clinical analysis of 23 cases of tracheal stenosis. 1. The frequency of tracheal stenosis was 23 cases among 1, 514 cases of tracheostomy (1.5%). 2. Under the age of 5, these are 12 cases (52.2 %). 3. The sex incidence was comprised of 18 males and 5 females. 4. The duration of tracheostomy ranges from 4 days to 16 months. 5. The primary diseases requiring tracheostomy were following; central nerve system lesions 11 cases, upper air way obstruction 10 cases, extrinsic respiratory failure 2 cases. 6. Severe wound infections were only 2 cases. 7. The methods of treatment applied to tracheal stenosis were following; closed observation only 5 cases, nasotracheal intubation combined steroid 5 cases, T-tube stent combined steroid 3 cases, fenestration op. 4 cases, revision 4 cases and transverse resection and end-to-end anastomosis 2 cases.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.1
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• pp.79-84
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• 2007

Acute respiratory distress syndrome(ARDS) is severe acute hypoxic respiratory failure state with dynamic impairment in oxygen and carbon dioxide transfer with the need for high levels of supplementary oxygen and a high minute ventilation. This syndrome is caused by pulmonary edema due to increased permeability of the alveolar capillary barrier by various factors. ARDS is an uncommon, but a potentially life-threatening complication. Therefore, immediate diagnosis and appropriate therapy must be performed. The present case is post-extubation ARDS immediately occurred in an orthognathic surgery patient who are healthy 19-year-old man. He rapidly recovered from ARDS without complication by early diagnosis and proper treatment. This case report was aimed to describe the process of the development, possible causes and the management of ARDS occurred in an orthognathic surgery patient

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.69-80
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• 1995

Renal proximal tubular hypertrophy and hyperfunction are known to be early manifestations of experimental and human diabetes. As the hypertrophy and hyperfunction have been suggested to be central components in the progression to renal failure, an understanding of their underlying causes is potentially important for the development of therapy. A primary rabbit kidney proximal tubule cell culture system was utilized to evaluate the possibility that the renal proximal tubular hypertrophy and hyperfunction observed in vivo in diabetes mellitus, can be attributed to effects of elevated glucose levels on membrane transport systems. Primary cultures of rabbit proximal tubules, which achieved confluence at 10 days, exhibited brush-border characteristics typical of proximal tubular cells. Northern analysis indicated $2.2{\sim}2.3$ and 2.0 kb Na/glucose cotransporter RNA species appeared in fresh and cultured proximal tubule cells after confluence, repectively. The cultured cells showed reduced Na/glucose cotransporter activity compared to fresh proximal tubules. Primary cultured proximal tubule cells incubated in medium containing 20 mM glucose have reduced ${\alpha}-MG$ transport compared to cells grown in 5 mM glucose. In the proximal tubule cultures incubated in medium containing 5 mM or 20 mM glucose, phlorizin at 0.5 mM inhibited 0.5 mM ${\alpha}-MG$ uptake by 84.35% or 91.85%, respectively. The uptake of 0.5 mM ${\alpha}-MG$ was similarly inhibited by 0.1 mM ouabain (41.97% or 48.03% inhibition was observed, respectively). In addition, ${\alpha}-MG$ uptake was inhibited to a greater extent when $Na^{+}$ was omitted from the uptake buffer (81.86% or 86.73% inhibition was observed, respectively). In cell homogenates derived from the primary cells grown in 5 mM glucose medium, the specific activity of the Na/K-ATPase $(6.17{\pm}1.27\;{\mu}mole\;Pi/mg\;protein/hr)$ was 1.56 fold lower than the values in cell homogenates treated with 360 mg/dl D-glucose, 20 mM $(9.67{\pm}1.22\;{\mu}mole\;Pi/mg\;protein/hr)$. Total $Rb^{+}$ uptake occurred at a significantly higher rate (1.60 fold increase) in primary cultured rabbit kidney proximal tubule cell monolayers incubated in 20 mM glucose medium $(10.48{\pm}2.45\;nM/mg\;protein/min)$ as compared with parallel cultures in 5 mM glucose medium. $Rb^{+}$ uptake rate in 5 mM glucose medium was reduced by 28% when the cultures were incubated with 1 mM ouabain. The increase of the $Rb^{+}$ uptake by rabbit kidney proximal tubule cells in 20 mM glucose could be attributed primarily to an increase in the rate of ouabain-sensitive $Rb^{+}$ uptake $(5\;mM\;to\;20\;mM;\;4.68{\pm}0.85\;to\;8.38{\pm}1.37\;nM/mg\;protein/min)$. In conclusion, the activity of the renal proximal tubular Na,K-ATPase is elevated in high glucose concentration. In contrast, the activity of the Nafglucose cotransport system is inhibited.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.233-239
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• 2010

Space loss of dental arch can appear when the proper position of teeth within the dental arch changes by a certain cause, because the balance of force makes changes about tooth position as well as alignment. The causes of space loss include proximal caries, early extraction, congenital missing of a tooth and hypodontia, etc. Among those causes of space loss, congenital missing of a tooth is more rarely observed in the primary dentition than in the permanent dentition. Congenital missing in the primary dentition is associated with that in the permanent dentition. Furthermore, it can cause space problem, such as mesial tilting or drift of adjacent teeth, space loss for permanent successors and dental arch constriction, etc. Primary lateral incisors is the most commonly involved, in the maxilla rather than in the mandible, but primary canine is rarely reported. In this patient, who visited the department of pediatric dentistry at Yonsei university dental hospital, it was observed that the maxillary right primary canine was congenitally missing and an odontoma was found insteadly. However, neither the space loss for the congenitally missing primary canine nor midline deviation is remarkable during the 2-year-10-month observation period. In addition, any clinical or radiographical symptom did not occur in spite of odontoma. Therefore, surgical enucleation of odontoma is planned according to the eruption of permanent lateral incisor or canine, unless eruption failure of permanent lateral incisor or canine nor cystic change around the odontoma is occurred. Through further evaluation, space maintainer or orthodontic treatment may be necessary.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.169-175
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• 2003

Purpose : The purpose was to evaluate the early result of revision of failed anterior cruciate ligament (ACL) reconstruction. Materials and Methods : From August 1997 to February 2002, this report presents the findings of 18 patients who had revision surgery for failed ACL reconstruction. There was an average of 39 $(7\~120)$months from index procedure to the time of revision. Allografts were used in 14 $(78\%)$cases and autografts were used in 4 $(22\%)$cases and the revision procedures were assisted by arthroscopic technique. The majority of chief complaints were instability in 16 $(89\%)$cases. Sixteen $(89\%)$ cases had 1 previous reconstruction, 2 $(11\%)$ cases had 2. Before and after revision, patients were evaluated by Lachman test, pivot shift test, KT 2000, radiographs, Lysholm score and HSS score and subjective satisfaction. Results : Average length of followup was 27 $(12\~60)$months. Preoperatively, all cases were positive in Lachman test and pivot shift test. After revision the majority of cases were negative. Objectively improving stability was confirmed by KT 2000 and all average KT 2000 was 7.75 $(3.5\~12.5)$mm preoperatively and 2.36 $(1.0\~6.0)$mm at final followup. Lysholm score and HSS score were also improved from 72.6 $(66\~77)$ and 72.5 $(68\~78)$ preoperatively to 89.2 $(80\~92)$ and 88.2 $(81\~92)$ at final followup. Most $(89\%)$ of patients were satisfied with their results. The most common causes of failed ACL reconstruction were malposition of femoral tunnel in 11 $(61\%)$cases. Conclusion : Arthroscopic revision ACL surgery with adequate graft for failed ACL reconstruction was successful in objectively and subjectively improving stability. However, considering the most common causes of failure after ACL reconstruction were errors in surgical technique, it is important that the primary ACL reconstruction should be performed with correct surgical technique.