• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.64-69
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• 2000

This paper investigates the equeeze film damping of a perforated planar micromechanical structure that oscillates in the normal direction to the substrate. Special focus has been places on the effect of holes and edges of the perforated planar microstructures on the squeeze film damping of oscillatory motions. Theoretical models and test structures of the squeeze film damping have been developed for the transversely oscillating perforated plates. A set of nine different test structures, having three different sized with three different numbers of perforations, has been fabricated and tested. The experimental Q-factors, measured from the fabricated test structures, are compared with the theoretical values, estimated from finite element analysis. It is found that the finite element analysis overestimates the Q-factors up to 150% of the experimental values. Major discrepancy comes from the inaccuracy of the zero pressure condition, placed by the finite element analysis along the perforated edges.

• Journal of Chest Surgery
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• v.11 no.1
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• pp.85-91
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• 1978

H.S. Lee, M.D., H.S. Yu, M.D. Esophageal perforation occurred rarely but often lead to a high mortality and morbidity. In the past, the main cause of esophageal perforation in Korea were instrumental perforation in patient with lye stricture of the esophagus. We experienced 9 cases of other forms of esophageal perforation from 1972 through 1977 and obtained the following results. 1. These 9 patients ranged from 10 months to 40 years in age at the time of admission. Six were women. 2. Causes of perforation are instrumental perforation in 3, foreign body perforation in 3, spontaneous perforation in 3 and one pneumatic esophageal perforation. 3. Perforation developed in a variety of locations in the esophagus. Three occurred in cervical part, two in the upper thoracic part, two in the lower thoracic part. 4. The main clinical symptoms and signs were dyspnea, subcutaneous emphysema, chest pain and fever. 5. Thoracic rentgenogram disclosed subcutaneous and mediastinal emphysema, widening of mediastinum and pleural effusion at the time of admission. 6. Complications of esophageal perforation were mediastinitis [7 cases], empyema [4 case], respiratory distress [4 cases] and sepsis [3 cases]. 7. In 3 deaths of the nine patients who sustained perforation of the esophagus, one was due to transfusion of infected blood and two of them were due to sepsis following empyema and mediastinitis. Early treatment [less than 24 hr] gave no hospital death, and good results obtained in the perforations of cervical and upper thoracic esophagus.

• KSBB Journal
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• v.32 no.3
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• pp.179-186
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• 2017

This study was undertaken to identify and characterize hemolytic Bacillus cereus isolated from commercial ssam-jang. The physiological and biochemical properties of isolate were first examined. Using the BIOLOG system, the isolate was identified and assigned to B. cereus MH-2. Phylogenetic tree of MH-2 was plotted based on 16S rRNA sequence comparisons. Hemolytic activity was observed around wells of sheep blood agar plates seeded with MH-2 cultures; the zone of hemolysis gradually increased with increasing incubation time of the cultures. Zymographic analysis estimated the molecular weight of the presumed hemolysis-causing molecule to be about 30 kDa. Survival rates of MH-2 cells decreased with increasing NaCl concentrations in the media. The stress shock proteins (e.g., DnaK and GroEL) induced by NaCl were reduced in proportion to the NaCl concentration and exposure period to B. cereus MH-2. Analysis of SDS-PAGE and Western blot revealed that the stress shock proteins, 70-kDa DnaK and 60-kDa GroEL were decreased proportionate to the NaCl concentrations as well as exposure period in exponentially growing cultures. Scanning electron microscopy demonstrated the presence of perforations and irregular rod forms with wrinkled surfaces in cells treated with NaCl.

• Advances in pediatric surgery
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• v.2 no.2
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• pp.81-87
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• 1996

Although nonoperative reduction plays a major role in the management of uncomplicated intussusception in the pediatric age group, surgical treatment is still a necessary alternative when nonoperative reduction is unsuccessful. The author analyzed the clinical features of 68 patients requiring operation in order to identify factors which might influence the type of operative management. A nine-year experience at Ewha Womans University Hospital was reviewed, and the findings compared to previous reports. Barium was used for the initial reduction attempt in 33 cases, saline in 35. Manual reduction by milking at operation achieved success in 41 cases(60.3%). Fifteen cases(22.1%) required resection of bowel, and 12 patients(17.6%) were found to have spontaneous and complete reduction of the intussusception at operation. Two cases had pathologic leading points. There were no perforations due to nonoperative reduction. There were no significant differences in demographic data, clinical findings, laboratory data, and anatomic type of intussusception between barium and saline reduction groups. However, a significant number of cases with spontaneous reduction were in saline reduction group(p<0.05). There was a slight chance of spontaneous reduction in infants under 6 month of age(p<0.001). Age under 6 month. body temperature over $38^{\circ}C$, symptom over 24 hours, and ileo-colic and ileo-ileo-colic intussusception contributed significantly to the necessity for bowel resection(p<0.05-0.001). The author believes that the age, body temperature, duration of illness, and anatomic type of intussusception strongly influence operative management.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.19 no.3
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• pp.193-198
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• 2016

Purpose: Spontaneous colon perforations are usually encountered as necrotizing enterocolitis in the neonatal period, but occur rarely in infants and children without pathological conditions. This study was conducted to describe its clinical implication beyond the neonatal period. Methods: Cases of spontaneous colon perforation confirmed after the operation were reviewed retrospectively and the clinicopathological characteristics were analyzed. Clinical data were compared according to the presence of pneumoperitoneum as initial findings. Results: Eleven patients were included in the study period and showed a history of hospitalization before transfer due to management for fever, respiratory or gastrointestinal problems. Six patients showed a sudden onset of abdominal distention and only seven patients showed a pneumoperitoneum as initial radiologic findings, however there were no significant clinicopathological differences. Perforation was found evenly in all segments of the colon, most commonly at the sigmoid colon in four cases. There were no specific pathologic or serologic causes of perforation. Conclusion: When previously healthy infants and children manifest a sustained fever with a sudden onset of abdominal distention during management for fever associated with respiratory or gastrointestinal problems, there is a great likelihood of colon perforation with no pathological condition. Prompt surgical management as timely decision-making is necessary in order to achieve a good progress.

• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.202-205
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• 2008

Tuberculous otitis media is a rare clnical finding. In the past, painless watery otorrhea and multiple perforations of the ear drum were considered classic signs and symptoms of tuberculous otitis media, but the clinical features have changed in recent years. The diagnosis of tuberculous otitis media is hampered by its low incidence and non-specific clinical features. Moreover, delayed diagnosis can result in irreversible and serious consequences, such as hearing loss, facial nerve palsy, and intracranial dissemination. Tuberculous otitis media should be considered in the differential diagnosis of antibiotic-refractory otitis media.

• Advances in pediatric surgery
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• v.3 no.1
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• pp.41-46
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• 1997

Perforation of the gastrointestinal tract in neonatal period has been associated with a grim prognosis. Recently there has been some improvement in survival. To evaluate the remaining pitfalls in management, 19 neonatal gastrointestinal perforation cases from May 1989 to July 1996 were analysed retrospectively. Seven patients were premature and low birth weight infants. Perforation was most common in the ileum(56.3%). Mechanical or functional obstruction distal to the perforation site was identified in 7 cases; Hirschsprung's disease 3, small bowel atresia 3, and anorectal malformation 1. These lesions were often not diagnosed until operation. Five cases of necrotizing enterocolitis and 1 of muscular defect were the other causes of perforation. In six cases, the cause of the perforation was not identified. Perinatal ischemic episodes were associated in five cases. Overall mortality was 15.1%. Because a considerable number of gastrointestinal perforations resulted from distal obstruction, pediatric surgeon should be alert for early identification and intervention of gastrointestinal obstruction, particularly in patients that are premature and have a history of ischemia.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.3
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• pp.264-269
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• 2015

Although sodium hypochlorite is the most frequently used canal irrigant during endodontic treatment, its complications are not as well recognized as its effectiveness. This report demonstrates that sodium hypochlorite extrusion during endodontic treatment can cause severe complications. A 5-year-old boy experienced immediate pain and swelling, ecchymosis in surrounding tissues, and profuse bleeding from the root canal during endodontic treatment, because of accidental extrusion of sodium hypochlorite. The patient was hospitalized, and analgesics and antibiotics were prescribed. Accidental extrusion of the irrigating solution occurs more frequently in teeth with immature apices, root resorption, and apical perforations; therefore, caution is needed. When such complications occur, proper management and medications are needed.

• Journal of the Korean Wood Science and Technology
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• v.24 no.1
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• pp.1-10
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• 1996

The frequency distribution diagrams of Korean diffuse-porous woods, 36 families, 75 genera, 145 species, 215 specimens in relation to habit and phenology were analyzed. As the habit character changes from shrub to tree, such quantitative features as vessel frequency, percentage of solitary vessels, length/diameter(L/D) ratio of vessel element decreased but tangential vessel diameter, fiber length/vessel element length(F/V) ratio increased. Qualitative features such as helical vessel wall thickening, diffuse distribution of longitudinal parenchyma, heterogeneous ray composition decreased, while alternate intervessel pits, libriform wood fiber, simple perforations increase. As the phenology character changes from evergreen to deciduous species, such quantitative features as percentage of solitary vessels, vessel element length and L/D ratio decreased but tangential vessel diameter, F/V ratio increased. Diffuse distribution of longitudinal parenchyma, heterogeneous ray composition, and crystals in qualitative features decreased, while alternate intervessel pits, libriform wood fiber, simple perforation of vessel element, ray width and ray height increased.

• Advances in pediatric surgery
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• v.9 no.1
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• pp.30-34
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• 2003

Spontaneous gastric perforation in the newborn is a rare disease that requires early diagnosis and prompt surgical treatment. Between 1988 and 2001 at the Department of Pediatric Surgery. Kyungpool National University Hospital, 9 cases of spontaneous gastric perforation were treated. Seven were males and two females. The mean gestational age and birth weight were 36.7 weeks and 2,455 g respectively. All patients presented with severe abdominal distention and pneumoperitoneum on cross table lateral film of the abdomen. Perforations were located on the anterior wall along the greater curvature of the stomach in six and on the posterior wall along the greater curvature in two. One case showed two sites of perforation on the anterior and posterior wall along the greater curvature. Six patients were managed with debridement and primary closure and the others with debridement and partial gastrectomy. Peritoneal drainage was not performed. There were four deaths; two from sepsis due to leakage from the anastomotic site, one as a result of acute renal failure, and the other by associated respiratory distress syndrome. Spontaneous gastric perforation in the newborn is usually located along the greater curvature. Elevated intragastric pressure is a possible cause of the perforation. Poor prognosis is related to associated diseases and prematurity.