• Composites Research
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• v.26 no.1
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• pp.21-28
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• 2013

The ballistic limit of Carbon/Epoxy composite laminates with the finite effective area are predicted by using the quasi-static perforation test and semi-empirical formula. The perforation energy were calculated from force-displacement curve in quasi-static perforation test. Also, the actual ballistic limit and penetration energy were obtained through the high-velocity impact test. The quasi-static perforation test and high-velocity impact test were conducted for the specimens with 3 different effective areas. In the high-velocity impact test, the air gun impact tester were used, and the ballistic and residual velocity was measured. The required inputs for the semi-empirical formula were determined by the quasi-static perforation tests and high-velocity impact tests. The comparison between semi-empirical formula and high-velocity impact test results were conducted and examined. The ballistic limits predicted by semi-empirical formula were agreed well with high-velocity impact test results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.191-196
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• 2000

Purpose This study is to report presurgical magnetic resonance imaging(MRI) findings of the temporomandibular joint which had perforation in the disc or its surrounding tissues and to improve its diagnostic rate using MRI. Patients and Methods The sample consisted of patients who visited the TMJ clinic at Yongdong Severance Hospital, Yonsei University, during the years, 1992 and 1997. They were diagnosed as TMJ internal derangement and received surgical treatment. We divided them into two groups. The first group comprised of 85 joints with perforated disc or its surrounding tissues and which were confirmed surgically. The second group of 62 joints which only had disc displacement without perforation, hyperemia or adhesion served as control. Results The preoperative diagnostic sensitivity of TMJ perforation using MRI was 74.1%. The MRI findings for diagnosis of the TMJ perforation were degenerative change of the condyle head or the articular fossa, bone to bone contact between the condyle head and the articular eminence or the articular fossa, bony spurring or osteophytosis of the condyle head, flattening of articular surface of the condyle head or the articular eminence, discontinuity of the disc and the arthrographic effect due to joint effusion. Conclusion The preoperative diagnostic sensitivity of TMJ perforation using MRI in this study was 74.1% which was lower than the diagnostic rate using the arthrogram. Further investigations are needed to improve the diagnostic accuracy of TMJ perforation using MRI.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.744-749
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• 1986

Even in the hands of the expert endoscopists, an occasional instrumental perforation of the esophagus occurs. But instrumental perforation of the esophagus should not be difficult to diagnose if the possibility is borne in mind. Occasionally patient with esophageal perforations show little reaction at first, but usually they develop systemic manifestation if surgical management is delayed. Early surgical drainage of esophageal perforation is very important & effective therapeutic method. The delayed surgical treatment of esophageal perforation would have increased the morbidity & mortality by allowing mediastinitis & empyema thoracis. We have experienced 6 cases of delayed surgical management of instrumental perforation of esophagus from May 1974 to April 1986 in the department of thoracic and cardiovascular surgery, Yonsei University, college of the medicine. The ages ranged from 4 years to 57 years. The underlying esophageal diseases consisted of esophageal stricture in 3 cases, foreign bodies in the esophagus in 2 cases and esophageal ca. in one case. Most clinical manifestations on admission were high fever, chest discomfort, chest pain, dysphagia and subcutaneous emphysema. Most complications due to esophageal rupture were acute mediastinitis with or without empyema thoracis. Failure to diagnose promptly and failure to promptly institute adequate treatment undoubtedly were largely responsible for this patients death. All 6 patients had been taken delayed surgical drainage more than 24 hours following esophageal perforation. One patient had been in the open drainage state for long time and the another patient has been in the tracheostomy with postintubation vocal cord ulceration. The third patient died due to respiratory failure and sepsis due to fulminant mediastinitis & empyema thoracis. Even if the patients with esophageal perforation have been taken delayed surgical management, the patients should be survived with aggressive & effective surgical drainage with intensive post-operative care.

• Journal of Forest and Environmental Science
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• v.8 no.1
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• pp.51-66
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• 1992

This study was carried out to investigate the micromorphology of vessel wall sculpture such as shape of perforation plate, perforation rim, steepness of perforation plate, occurrence of vestured pit, warty layer and ray-vessel pitting on 13 species of Fagaceae in Korea. The results were summarized as follows ; 1. In the species examined, all sample species except Fagus crenata var. multinervis have simple perforation plate. But Fagus crenata var. multinervis has simple and scalariform perforation plate (it was called to combination perforation plate) in a tree stem. 2. The shapes of perforation rim could be classified into five types; Type A without tail, Type B with small tail on both sides, Type C with long tail on both sides, Type D with tail only one side and Type E with the very short interval between perforations. Among five types, Type Band C have higer frequency of distribution than the others. 3. The steepness of perforation plate measured was about 20 degree on pore zone and 43 degree on outside parts of pore zone. 4. Species with vestured pit were Q. aliena, Q, dentata, Q. variabilis, Fagus crenata var. multinervis, Castanopsis cuspidata var sieboldii, Q. acuta, Q. stenophylla, and Q. glauca. But the extent of vesturing was very slight and vestured pits were observed mainly in ray-vessel pit of some vessel elements. 5. Species with warty layer on the inner surface wall of all vessel elements were Q. acuta, Q. stenophylla, Q. glauca, Fagus crenata var. multinervis and species with warty layer of some vessel elements were Q. aliena, Q, dentata, Q. variabilis, Castanopsis cuspidata var. sieboldii. 6. Species with palisade ray-vessel pit were Q. acuta, Q. stenophylla, Q. glauca, Castanea crenata, Castanea bungeana, Q. aliena, Q. serrata, Q. mongolica, and species with scalariform ray-vessel pit was Fagus crenata var. multinervis and species with oval ray-vessel pit were Q, dentata, Castanopsis cuspidata var sieboldii.

• Restorative Dentistry and Endodontics
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• v.40 no.1
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• pp.58-67
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• 2015

Objectives: This study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth. Materials and Methods: Mesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test. Results: The sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed. Conclusions: If it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended.

• Journal of Chest Surgery
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• v.21 no.5
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• pp.935-940
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• 1988

Perforated esophagus is a surgical emergency; it is the most serious and frequently the most rapidly lethal perforation of the gastrointestinal tract. Contamination of the mediastinum and often a pleural cavity with corrosive fluids, food material and bacteria leads to cardiorespiratory embarrassment, shock, major fluid losses and fulminating infection. Despite the improved diagnostic and treatment modalities, a perforation or leak from the esophagus remains a major source of morbidity and mortality. When esophageal perforation occurs, a successful outcome can be expected only when it is diagnosed soon after the event and repaired early. Esophageal perforations have a poor prognosis after delayed surgical treatment. With the use of the Thai onlay gastric patch method, a case of postemetic spontaneous perforation of the esophagus was successfully managed 6days after the event.

• Journal of Korean Neurosurgical Society
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• v.42 no.3
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• pp.232-234
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• 2007

We describe the extrusion of a ventriculoperitoneal shunt catheter from the anus after double perforation of the large bowel in a 3-year-old girl with hydrocephalus. She was admitted because the tip of the peritoneal catheter protruded 10 cm from the anus and clear cerebrospinal fluid dripped from the tip. Emergency laparotomy was performed. The distal peritoneal catheter perforated and penetrated the sigmoid colon and re-perforated into the rectal cavity. The distal peritoneal catheter was removed, the proximal catheter was exposed for external drainage, and intravenous broad-spectrum antibiotics were administered for 2 weeks. After control of infection, the shunt system was completely removed. Bowel perforation by a peritoneal catheter is a rare complication. Diagnosis is often difficult, delayed, and its incidence is likely underestimated. Most bowel perforation is the result of infection as opposed to technical errors.

• Computers and Concrete
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• v.8 no.1
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• pp.111-123
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• 2011

Severe element distortion problem is observed in finite element mesh while performing numerical simulations of high velocity steel projectiles penetration/perforation of concrete targets using finite element method (FEM). This problem of element distortion in Lagrangian formulation of FEM can be resolved by using element erosion methodology. Element erosion approach is applied in the finite element program by defining failure parameters as a condition for element elimination. In this study strain parameters for both compression and tension at failure are used as failure criteria. Since no direct method exists to determine these values, a calibration approach is used to establish suitable failure strain values while performing numerical simulations of ogive-nose steel projectile penetration/perforation into concrete target. A range of erosion parameters is suggested and adopted in concrete penetration/perforation tests to validate the suggested values. Good agreement between the numerical and field data is observed.

• Advances in pediatric surgery
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• v.3 no.2
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• pp.168-171
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• 1997

Appendiceal perforation is uncommon in the neonate. Diess reported the first case in 1908. Approximately 111 additional cases have been reported since that time. However, with exclusion of neonatal appendicitis associated with inguinal or umbilical hernias, necrotizing enterocolitis, meconium plug, and Hirschsprung's disease, there are only 36 cases of primary neonatal appendicitis. We treated a 12 days old boy with perforation of the appendix. The infant was 3000 g at birth and had a normal spontaneous vaginal delivary at 35 weeks of gestation. The mother was 31-year-old and had premature rupture of membrane. After normal feeding for the first 5 days of life, the infant had emesis of undigested milk, decreased activity and jaundice. The baby was admitted to the Pediatrics. Progressive abdominal distension, fever, decreased activity, and vomitting developed over the next six days. Erect abdominal radiography showed pneumoperitoneum. At exploratory laparotomy, a $0.8{\times}0.6$ cm sized perforation was noted at antime-senteric border of midportion of the appendix. Trasmural inflammation and the presence of ganglion cells were noticed on histology.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.7 no.1
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• pp.119-123
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• 2004

Meckel's diverticulum is the most common malformation of gastrointestinal tract. Symptoms of Meckel's diverticulum usually arise within 2 years of life. The most common presentations include hemorrhage, perforation, diverticulitis and intestinal obstruction. Perforation of the Meckel's diverticulum in a neonate is uncommon but life threatening condition. We describe the first case of perforation of Meckel's diverticulum in a 1-day-old neonate who presented with abdominal distension without hemorrhage.