• Journal of Mechanical Science and Technology
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• 제14권5호
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• pp.562-568
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• 2000

The pressure in a water-entry induced cavity, is analyzed up to the closed cavity (bubble). Water-entry is a highly transient phenomenon, and the evolution of the water-entry cavity must be explained by considering the entry speed, shape of the solid body, atmosphere pressure, and cavity pressure as the primary variables. This work is an extension of the cavity dynamics model recently reported by Lee (l997a). To extend the model for a wide range of entry speeds the cavity pressure is calculated from a one-dimensional quasi-steady flow model. The estimation of the cavity pressure allows us to explain the experimentally observed surface closure phenomena at low entry speeds. Predictions for the time of surface closure are compared with the published experimental data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.141-146
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• 2000

Crack closure and growth behavior of physically short fatigue cracks under random loading are investigated by performing narrow- and wide-band random loading tests for various stress ratios. The importance of the crack closure phenomenon is examined by predicting the growth lives of short cracks using obtained crack opening behavior. Artificially prepared two-dimensional, short through-thickness cracks are used. The crack opening load of short cracks is much lower under random loading than under constant-amplitude loading corresponding to the largest load cycle in a random load history. This result indicates that the largest load cycle in a random load history has an effect to enhance crack opening of short cracks. Most of the life prediction ratios are within the factor of 2 scatter band except several data at very short crack sizes, indicating that crack growth predictions based on the measured crack opening data are excellent. From the results obtained in this study, it can be concluded that crack closure is the primary factor governing fatigue crack growth of short cracks under random loading as well as under constant-amplitude loading.

• Archives of Plastic Surgery
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• 제43권1호
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• pp.26-31
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• 2016

Background The global prevalence of myelomeningocele has been reported to be 0.8-1 per 1,000 live births. Early closure of the defect is considered to be the standard of care. Various surgical methods have been reported, such as primary skin closure, local skin flaps, musculocutaneous flaps, and skin grafts. The aim of this study was to describe the clinical characteristics of myelomeningocele defects and present the surgical outcomes of recent cases of myelomeningocele at our institution. Methods Patients who underwent surgical closure of myelomeningocele at our institution from January 2004 to December 2013 were included in this study. A retrospective chart review of their medical records was performed, and comorbidities, defect size, location, surgical procedures, complications, and the final results were analyzed. Results A total of 14 patients underwent surgical closure for myelomeningocele defects. Twelve cases were closed with direct skin repair, while two cases required local skin flaps to cover the skin defects. Three cases of infection occurred, requiring incision and either drainage or removal of allogenic materials. One case of partial flap necrosis occurred, requiring secondary revision using a rotational flap and a full-thickness skin graft. Despite these complications, all wounds eventually healed completely. Conclusions Most myelomeningocele defects can be managed by direct skin repair alone. In cases of large defects, in which direct repair is not possible, local flaps may be used to cover the defect. Complications such as wound dehiscence and partial flap necrosis occurred in this study; however, all such complications were successfully managed with simple ancillary procedures.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제25권2호
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• pp.147-162
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• 2022

Purpose: To design a prospective study on endovascular closure of congenital portosystemic shunts. The primary endpoint was to assess the safety of endovascular closure. The secondary endpoint was to evaluate the clinical, analytical and imaging outcomes of treatment. Methods: Fifteen patients (age range: 2 days to 21 years; 10 male) were referred to our center due to congenital portosystemic shunts. The following data were collected prior to treatment: age, sex, medical history, clinical and analytical data, urine trimethylaminuria, abdominal-US, and body-CT. The following data were collected at the time of intervention: anatomical and hemodynamic characteristics of the shunts, device used, and closure success. The following data were collected at various post-intervention time points: during hospital stay (to confirm shunt closure and detect complications) and at one year after (for clinical, analytical, and imaging purposes). Results: The treatment was successful in 12 participants, migration of the device was observed in two, while acute splanchnic thrombosis was observed in one. Off-label devices were used in attempting to close the side-to-side shunts, and success was achieved using Amplatzer™ Ductus-Occluder and Amplatzer™ Muscular-Vascular-Septal-Defect-Occluder. The main changes were: increased prothrombin activity (p=0.043); decreased AST, ALT, GGT, and bilirubin (p=0.007, p=0.056, p=0.036, p=0.013); thrombocytopenia resolution (p=0.131); expansion of portal veins (p=0.005); normalization of Doppler portal flow (100%); regression of liver nodules (p=0.001); ammonia normalization (p=0.003); and disappearance of trimethylaminuria (p=0.285). Conclusion: Endovascular closure is effective. Our results support the indication of endovascular closure for side-to-side shunts and for cases of congenital absence of portal vein.

• Archives of Plastic Surgery
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• 제32권3호
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• pp.393-396
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• 2005

The cutaneous aspergillosis is one of the most common dermatologic manifestations of disseminated infections associated with the Aspergillus organisms, but the isolated primary cutaneous disease itself can rarely occur in an immunocompetent host. We report a case of the primary cutaneous aspergillosis on the scalp and the neck in a 39-year-old immunocompetent male patient. There was a single purulent ulcer surrounded by the erythematous indurated plaque on the scalp with multiple satellite papules and a multi-lobulated granulomatous plaque with a crust on the neck. Skin biopsy demonstrated a fungus, the Aspergillus, in the deep dermis as the etiologic agent. No evidence of involvement in other organs was found. The patient exhibited no other apparent systemic diseases nor immunologic defects. An elliptical excision and a primary closure was performed, and the adjuvant antifungal treatment, oral itraconazole, was applied to prevent the recurrence by the satellite lesions.

• Archives of Plastic Surgery
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• 제45권4호
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• pp.384-387
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• 2018

Blepharoplasty is one of the most commonly performed aesthetic procedures. Surgical complications are rare, but can have severe consequences, such as permanent vision loss. In this report, we describe a patient who developed primary angle-closure glaucoma (ACG) with associated vision loss after a oculoplastic procedure using local anesthesia. So far, six similar cases have been described in the literature. It is believed that acute ACG is triggered by the surgical procedure in patients with predisposing risk factors such as a cataract. Surgical triggering factors include the use of buffered lidocaine/xylocaine with adrenaline/epinephrine, stress, and coverage of the eyes postoperatively. Due to postoperative analgesic use, the clinical presentation can be mild and atypical, leading to a significant diagnostic delay. Acute ACG should therefore be excluded in each patient with postoperative complaints by assessing pupillary reactions. If a fixed mid-wide pupil is observed in an ophthalmologic examination, an immediate ophthalmology referral is warranted. Surgeons should be aware of this rare complication in order to offer treatment at an early stage and to minimize the chance of irreversible vision loss.

• Archives of Plastic Surgery
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• 제39권3호
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• pp.253-256
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• 2012

A radial forearm free flap has been conventionally used for urethral reconstruction. However, aesthetic and functional complications occur frequently at the donor site. The use of a superficial circumflex iliac artery perforator (SCIP) flap can resolve these disadvantages. Here, we report our case with a review of literature. A 69-year-old man visited our hospital with multiple contusions of the abdomen and genital amputation. After necrotic tissue debridement, the length of the residual corpus carvernosum was 1.5 cm and that of the corpus spongiosum and urethra was 1 cm. For the reconstruction of the penis, a SCIP flap and anterolateral thigh free flap was performed. The primary closure was performed at the donor site. Three weeks postoperatively, the patient had a urethral foley catheter removed. The neourethra was functioning well without stricture. Four months postoperatively, the patient had no complications such as urethral stricture. A good recovery was also achieved with no aesthetic deficits at the donor site. SCIP flap is appropriate for urethral reconstruction. Because of its proximity to the recipient sites, it makes surgical preparation easier and the primary closure at the donor site available. It is also advantageous in that its location is almost unnoticeable.

• 대한기관식도과학회지
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• 제8권1호
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• pp.61-65
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• 2002

Background : Acquired tracheoesophageal fistula(TEF) results mostly from Prolonged tracheal intubation and insertion of nasogastric tube. Although the incidence has decreased since the usage of low pressure, high volume cuff of endotracheal tube, it is seldom cured spontaneously and needs surgical treatment. Material and Methods : We have retrospectively reviewed five cases of TEF who underwent surgical treatment for cure from March, 1990 to September, 2001 and analyzed the cause, treatment, postoperative complications and prognostic factors. Results : Majority were men(80% : 4 of 5 patients) and the mean age was 29.4 years old(range, 11-58). The most predominant etiology was prolonged intubation or tracheostomy(80% : 4 of 5 patients) and 3 of 5 patients were treated by tracheal resection and end to end anastomosis with primary closure of esophagus. Postoperative complications occurred in 4 patients the most common complications were wound infection(4 cases) and esophageal leakage(2 cases). Extubation was done on postoperative day 11.5(range, 1-33) days, and factors causing delayed extubation were status esophagus. epilepticus, edema, and tracheal stenosis. Conclusion : Spontaneous closure of TEF is seldom possible and the surgical treatment of choice is tracheal resection and end to end anastomosis with primary repair of the esophagus. preoperative pulmonary rehabilitation and early extubation postoperatively are important factors for success.

• 한국추진공학회지
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• 제9권2호
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• pp.70-77
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• 2005

축소-팽창 디퓨저가 장착된 초음속 이젝터를 제작하여, 다양한 위치에서의 측정된 압력으로 부유동의 초음속 시동조건을 찾아내었다. 우선 부유동 흡입구의 크기의 영향을 알아내기 위하여 다양한 흡입구 직경으로 실험하였으며, 부유동의 초음속 시동은 흡입구 직경과 축소-팽창 디퓨저 직경의 비, d/D가 0.306 미만인 경우에만 일어났다. 이보다 큰 d/D에서는, 아음속 시동이 먼저 시작되고, 흡입구를 막으면서 주유동의 유입이 전 유동장을 채우게 되어 수직 충격파를 축소-팽창 디퓨저의 하류로 내려보내게 된다 이러한 상황에서 다시 흡입구를 열어도 히스테리시스의 영향으로 초음속 시동이 유지된다.

• Journal of Trauma and Injury
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• 제36권4호
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• pp.447-450
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• 2023

Traumatic abdominal wall hernia is a rare presentation, most commonly reported in the context of motor vehicle accidents and associated with blunt abdominal injuries and handlebar injuries in the pediatric population. A 13-year-old boy presented with multiple traumatic injuries and hemodynamic instability after a high-speed motor vehicle accident. His injuries consisted of massive traumatic abdominal wall hernia (grade 4) with bowel injury and perforation, blunt aortic injury, a Chance fracture, hemopneumothorax, and a humeral shaft fracture. Initial surgical management included partial resection of the terminal ileum, sigmoid colon, and descending colon. Laparostomy was managed with negative pressure wound therapy. The patient underwent skin-only primary closure of the abdominal wall and required multiple returns to theatre for debridement, dressing changes, and repair of other injuries. Various surgical management options for abdominal wall closure were considered. In total, he underwent 36 procedures. The multiple injuries had competing management aims, which required close collaboration between specialist clinicians to form an individualized management plan. The severity and complexity of this injury was of a scale not previously experienced by many clinicians and benefited from intrahospital and interhospital specialist collaboration. The ideal aim of primary surgical repair was not possible in this case of a giant abdominal wall defect.