• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.859-869
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• 2015

In this study, we analyze the problem of wedge cracks, which are geometrically unsymmetrical in transversely piezoelectric materials. A single concentrated antiplane mechanical load and inplane electrical load are applied at the point of the wedge surface, while one concentrated antiplane load is applied at the crack surface. The crack surfaces are considered as permeable thin slits, where both the normal component of electric displacement and the electric potential are assumed to be continuous across these slits. Using Mellin transform method, the problem is formulated and the Wiener-Hopf equation is derived. By solving the equation, the solution is obtained in a closed form. The intensity factors of the stress and the electric displacement are obtained for any crack length as well as inclined and wedge angles. Based on the results, the intensity factors are independent of the applied electric loads. The electric displacement intensity factor is always dependent on that of stress intensity factor, while the electric field intensity factor is zero. In addition, the energy release rate is computed. These solutions can be used as fundamental solutions which can be superposed to arbitrary electromechanical loadings.

• Journal of Chest Surgery
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• v.56 no.2
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• pp.140-142
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• 2023

The azygos vein sometimes merges abnormally across the right upper lobe of the lung and it hangs at the lower edge of a membranous septum, called the meso-azygos. The septum invaginates the lobe and makes a fissure. The smaller medial part of the right upper lobe is called an azygos lobe. A 16-year-old male patient was diagnosed with right-sided pneumothorax, and a closed thoracostomy was done in the emergency room. During elective wedge resection including the bulla, the meso-azygos, abnormal azygos vein, and azygos lobe were detected. We reviewed the computed tomography images and found that the azygos lobe had re-expanded laterally, not medially, to the meso-azygos after the closed thoracostomy in the emergency room. The patient had been diagnosed with left-sided pneumothorax a year ago, and no one noticed the azygos lobe at that time. We report the intraoperative findings and comparative images of a migratory azygos lobe.

• Journal of Chest Surgery
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• v.24 no.5
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• pp.451-458
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• 1991

We have observed 101 cases of recurrent spontaneous pneumothorax from Sep. 1979 to Dec. 1989 at the Department of Thoracic & Cardiovascular Surgery, College of Medicine, Inje University, Pusan Paik Hospital and the result obtained as follows. 1] Age range of patients was the first decade to seventh decade. Males outnumbered females by 6.7: l. One or two episodes of recurrent attack were noted in majority cases. 2] In distribution of the lesion sites, right side was 55 cases[55.4%], left 42 cases[41.9%], and bilateral 4 cases[3.0%]. 3] In clinical manifestations, abrupt onset of dyspnea was 78 cases[77.2%], chest pain 48 cases[47.5%], cough 9 cases[8.9%] and chest discomfort 8 cases[7.9%]. 4] Of 101 cases, 48 cases were associated with pulmonary tuberculosis and other cases were associated with subpleural bullae and blebs[26 cases], emphysema[7 cases], bronchiectasis[2 cases], lung cancer[1 case], and silicosis[1 case], 5] In 88 cases[87.2%] of patients, the magnitude of collapse was above 50% in plain chest film. 6] The interval of recurrence after last attack was frequently within 1 year. 7] In the management, closed thoracostomy with underwater-sealed drainage was applied in first recurrent 53 cases but 2nd recurrence was developed in 16 cases. In 52 cases, surgical management was applied. The pleurodesis with chemical agent[tetracycline] via chest tube was applied in 2 cases. Among 51 cases subjected to the open thoracotomy, pleural abrasion was performed in 3 cases, excision of bullae & blebs in 12 cases, wedge resection in 28 cases, lobectomy in 6 cases and wedge resection combined with lobectomy in 2 cases. In one case subjected to the median sternotomy, wedge resection on both lung apex was performed. 8] Postoperative complications were developed in 8 cases but not serious.

• Journal of Chest Surgery
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• v.23 no.2
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• pp.231-235
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• 1990

Segmental resection or wedge resection of the lung and direct cutting across of bronchi frequently results in postoperative airleaks or bronchopleural fistula in some cases. Many methods have been devised to handle air leak problems by oversuturing the raw edges, the application of pleural onlay flaps, the use of cautery or tissue adhesives, but these still has not solved the problem of air leaking from raw surfaces of the lung with only partial successful we have tried the use of histoacryl to closure the raw surface of the resected lung and compared it’s results with of the closure with chromic catgut sutures in cats from May 1989 to Jan. 1990 at the department of the thoracic and cardiovascular surgery, Yonsei University, College of Medicine. Ninety lobe of the lungs were used in this study and forty nine of which have been divided segmentally and closed with histoacryl on the raw surfaces. Forty one of which have been divided segmentally and closed with sutures using chromic catgut for control. There were air leakages in twelve cases among 49 cases with applying histoacryl and airleak were in two cases among 12 cases with reapply histoacryl, But there were air leak in two cases among 41 cases with sutures using chromic catgut and airleak were in one case among with resutures using chromic catgut.

• Journal of Medicine and Life Science
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• v.17 no.1
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• pp.16-20
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• 2020

Spontaneous hemopneumothorax is a rare disease, and it can cause life threatening condition. It is characterized by the accumulation of more than 400 mL of blood and air in the pleural cavity without any other apparent causes. A previously healthy 22-year-old female patient presented with acute chest pain and dyspnea. Chest X-ray and computed tomography revealed a massive hemopneumothorax in the left hemithorax. The images showed a completely collapsed left lung with right-sided tracheal deviation, several pleural adhesion bands, and fluid collection with air-fluid level. We emergently performed a closed thoracostomy, and then 560 mL of fresh bloods were initially drained. We considered an emergent video-assisted thoracoscopic surgery for pulmonary wedge resection and bleeding control because of the massive hemothorax. However, the patient's vital signs were stabilized after blood transfusion and supportive cares for re-expansion pulmonary edema. The patient discharged from the hospital on 11^th in-hospital day after removal of the chest tube, and there had not been any recurrence of the pneumothorax for 10 months. We suggest that treatment strategy should be decided upon individually based on the patient's condition and clinical course of the disease.

• Journal of Medicine and Life Science
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• v.17 no.1
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• pp.25-28
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• 2020

The prevalence of pulmonary pargonimiasis in Korea has been steadily decreasing due to develop of the public health, and there have been few clinical cases of paragonimiasis infections, especially in pneumothorax. A 22-year-old man referred to emergency department for dyspnea and chest pain. The right lung was totally collapsed on a chest X-ray. We emergently performed a closed thoracostomy with a 28-Fr chest tube. However, the air leak from the chest tube persisted for three days after the closed thoracostomy. A chest computed tomography showed multiple subpleural consolidative nodular lesions and mixed ground-glass attenuation nodules. We potentially suspected a secondary pneumothorax resulting from pulmonary paragonimiasis infection because the patient was a Chinese man who was working at a Korean restaurant. We decided to perform a medical treatment instead of pulmonary wedge resections. The air leak was discontinued three days after the prescription of praziquantel. The patient was discharged nine days after the admission. We suggest that anti-parasitic drugs are very effective in the secondary pneumothorax resulting from paragonimiasis.

• Journal of the Chungcheong Mathematical Society
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• v.13 no.1
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• pp.71-78
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• 2000

The main goal of this paper is to prove the following theorem ; Let (X, ${\rho}_1$) be a fuzzy normed linear space over K and (Y, ${\rho}_2$) be a fuzzy Banach space over K. If ${\chi}_{B_{{\parallel}{\cdot}{\parallel}}}{\supseteq}{\rho}*$, then (CF(X,Y), ${\rho}*$) is a fuzzy Banach space, where ${\rho}*(f)={\vee}{\lbrace}{\theta}{\wedge}\frac{1}{t({\theta},f)}\;{\mid}\;{\theta}{\in}(0,1){\rbrace}$, $f{\in}CF(X,Y)$, $B_{{\parallel}{\cdot}{\parallel}}$ is the closed unit ball on (CF(X, Y), ${\parallel}{\cdot}{\parallel}$ and ${\parallel}f{\parallel}={\vee}{\lbrace}P^2_{{\alpha}^-}(f(x))\;{\mid}\;P^1_{{\alpha}^-}(x)=1,\;x{\in}X{\rbrace}$, $f{\in}CF(X,Y)$, ${\alpha}{\in}(0,1)$.

• Journal of Chest Surgery
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• v.17 no.1
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• pp.82-88
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• 1984

Total 310 cases of spontaneous pneumothorax in 281 patients were analyzed to review the results of surgical treatment for this condition. Clinical data on the age & sex distribution, recurrence, etiologic conditions and on the other aspects of spontaneous neumothorax were summarized. The results of surgical management of spontaneous pneumothorax are followings; 205 out of 310 cases[66.1%] were cured by closed thoracostomies. 82 cases[26.5%] were cured by thoracotomy. The indications of thoracotomy were 1] persistent air leakage, 2] history of recurrences, 3] blebs or bullae on thoracoscopy, 4] associated parenchymal lesion, 5] pneumothorax caused by paragonimiasis. Other reasons of thoracotomy were bilateral pneumothorax and inadequate expansion due to chronicity. Excision of blebs or wedge resection was performed in most cases with good result. Lobectomy [9 case] or pneumonectomy [3 cases] was carried out depending on the pathological involvement of the lung. There was no operative death and only one case showed recurrent pneumothorax during follow-up after thoracotomy.

• Journal of the Korean Mathematical Society
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• v.44 no.6
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• pp.1479-1503
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• 2007

In this paper, we study a strong k-deformation retract derived from a relative k-homotopy and investigate its properties in relation to both a k-homotopic thinning and the k-fundamental group. Moreover, we show that the k-fundamental group of a wedge product of closed k-curves not k-contractible is a free group by the use of some properties of both a strong k-deformation retract and a digital covering. Finally, we write an algorithm for calculating the k-fundamental group of a dosed k-curve by the use of a k-homotopic thinning.

• Journal of Chest Surgery
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• v.26 no.3
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• pp.204-208
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• 1993

The review of 68 patients, who were diagnosed as spontaneous pneumothorax during the period from Dec, 1991. to Jul, 1992. were performed thoracoscopy of 70 cases under local anesthesia with 1% lidocaine at the department of thoracic & cardiovascular surgery, HanYang University Hospital. Clinical data on distribution of Age & Sex, Location, Frequency of Reccurrence and other aspects of pneumothorax were summerized.37 cases were treated by thoracoscopic management and closed thoracostomy. As thoracoscopic management, Electrocauterization of bullae or blebs[37 cases], Endo-clip application [2 cases], Removal of foreign body[1 case] were performed. 31 cases were cured by open thoracotomy. The thoracotomy indications under thoracoscopic finding were followed as: 1. Severe pulmonary adhesion and destroyed lung parenchyme 2. multiple bullae or blebs on several areas 3. finding of pulmonary tuberculous caseous lesion 4. persistant air leakage after 7 days from thoracoscopic management Excision, wedge resection of bullae or blebs was performed in most cases [22 cases], 2 cases by median sternotomy and Segmentectomy of 7 cases were carried out depending on the pathologic change of lung.There was no operative mortality and Follow-up for all patients were showed good results.