• Journal of Chest Surgery
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• 제27권7호
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• pp.610-616
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• 1994

Myasthenia gravis is a rare condition, affecting only 1/75000. It is characterized by weakness and fatigue of the voluntary muscles due to impaired neuromuscular transmission at the acetylcholine receptor site. It is probably caused by an autoimmune mechanism leading to reduction of the available nicotinic acetylcholine receptors at the neuromuscular junction. A relationship between the thymus and myasthenia gravis was suggested by Weigert in 1901, and Blalock was the first to report the efficiency of thymectomy in the treatment of myasthnia gravis in 1939. Since that time, thymectomy has become increasingly important in managing patients with myasthenia gravis. Fourteen patients with myasthenia gravis underwent thymectomy between September 1987 and March 1994 and got the following results; 1. The sex distribution was 10 females and 4 males with ages ranging from 15 to 51 years[mean, 34.8 years]. 2. Clinical manifestation of ocular symptoms were seen in all cases, dysphagia in 12[85.7%], extremity weakness in 11 [78.6 %], and dyspnea in 3 [21.4 %]. 3. According to the modified Osserman`s classification, 8 patients were in group IIb, 3 in IIa, 2 in I and 1 in IIc, respectively. 4. Histopathologic examination of the resected thymuses revealed hyperplasia in 8 patients, benign thymoma in 3, and malignant thymoma in 3. 5. There were no perioperative or immediate postoperative deaths but one patient died about two months after the thymectomy due to respiratory failure. 6. During the follow-up period, 11 patients [78.6 %] showed clinical improvement. Among them, 4 cases [28.6 %] showed complete remission, 3 [21.4 %] showed marked improvement, and 4 [28.6 %] showed subjective improvement. 7. Among the 8 patients with thymic hyperplasia, clinical improvement was noticed in 7 patients 5 %]. Among the 6 patients with thymoma, 4 patients [66.7 %] showed improvement.

• 대한한방내과학회지
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• 제21권4호
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• pp.683-686
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• 2000

Vesicoureteral reflux(VUR) is a state that urine regurge from bladder to ureter and kidney because of congenital, structural, functional abnormality of ureterovesical junction and lower urinary tract than bladder. It may be the primary cause of recurrent urinary tract infection(UTI) in chindhood, If urine regurge with UTI, it can cause renal damage, leading to scar formation, hypertension, chronic renal failure, But upper complications can be prevented by early diagnosis and proper treatment of VUR and UTI, so clinician must focus on them in treatment of VUR. We had experienced a case of recurrent UTI with VUR regardless of consistent antibiotics therapy in 7 years old boy, Chief complain was urinary frequency, The symptom of urinary frequency was successfully treated by herb medicine(Gamijihwag-tang), So, we report this case with a brief review of related literatures.

• Geomechanics and Engineering
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• 제23권1호
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• pp.85-92
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• 2020

This study adopted soil test and laboratory physical model experiments to simulate the tailings impoundment accumulation process according to the principle of similarity. Relying on the practical engineering, it analyzed the tailings deposition characteristics on dry beach surface during the damming process, as well as the variation rules of dam saturation line. Results suggested that, the tailings particles gradually became finer along the dry beach surface to inside the impoundment. The particle size suddenly changed at the junction between the deposited beach and the water surface, which displayed an obvious coarsening phenomenon. Besides, the deposited beach exhibited the vertical feature of coarse upward and fine downward on the whole. Additionally, in the physical model, the saturation line elevated with the increase in dam height, and its amplitude was relatively obvious within the range of 1.0-4.5 m away from the initial dam. Under flood condition, the saturation line height was higher than that under normal condition on the whole, with the maximum height difference of 4 cm. This study could provide an important theoretical basis for further studies on dam failure experiments and the evolution rules of leaked tailings flow.

• 한국임상수의학회지
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• 제29권2호
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• pp.165-168
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• 2012

14년 령의 중성화 하지 않은 수컷 Siberian Husky는 1개월 전부터 혈뇨, 기면, 식욕부진을 보였다. 신체검사상 복부 팽만과 통증을 확인할 수 있었다. 혈액 및 혈청 화학 검사상 빈혈과 질소혈증을 확인할 수 있었다. 방사선 검사 상 신장의 비대를 확인할 수 있었으며 초음파 검사 상 피수질의 경계가 불분명하며 피질의 에코가 증가한 신장을 확인할 수 있었다. 뇨검사 상에서는 혈뇨와 단백뇨를 확인할 수 있었으며 초기의 감별 진단으로는 신부전, 방광염, 신우신염과 종양을 생각했다. 환자의 상태는 내원 후 계속적으로 악화되었으며 폐사했다. 부검 상에서 복강 내 출혈과 양측 신장의 종양을 확인할 수 있었다. 조직검사 상에서 혈관육종을 진단하였다. 본 증례에서는 개에서 비특이적으로 발생하는 양측성의 신장원성 혈관육종에 대해서 다룬다.

• 한국주조공학회지
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• 제20권4호
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• pp.240-246
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• 2000

Surface layer properties such as composition, phase, hardness, and oxide layer condition are very important if the main failure mechanism of metals is wear. Generally, stable and dense oxide layers are known to decrease the wear rate of metals by prohibition of metallic junction occurred between bare metals. Addition of Si above 4 wt% to DCI(Ductile Cast Iron) is reported to enhance the significant oxidation resistance by forming the silicon-rich surface layer which inhibits further oxidation. And addition of up to 2 wt% Mo to high Si ductile iron produces significant increases in high temperature tensile strength, creep strength, thermal fatigue resistance and oxidation resistance. High pressure wear characteristics of unalloyed DCI(Ductile cast Iron), 4.46 wt% Si ductile iron, 4.3 wt% Si-0.52 wt% Mo ductile iron were investigated through unlubricated pin-on-disc wear test. Wear test was carried out at speed of 23m/min, under pressure of 3 MPa and 3.3 MPa. Wear surfaces of each specimen were observed by SEM to determine the wear mechanism under high pressure wear condition. Addition of Si 4.46 wt% severely deteriorated wear property of ductile iron compared to unalloyed DCI. But combined addition of Si 4.3 wt%andMo0.52wt%decreasedthefrictioncoefficient(${\mu}$)ofductileironsandremarkablydelayedthemild-severeweartransition.

• 한국세라믹학회지
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• 제27권8호
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• pp.991-1003
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• 1990

A precipitation method, one of the most effective liquid phase reaction methods, was adopted in order to prepare high-tech Al2O3/ZrO2 composite ceramics. Al2(SO4)3.18H2O, ZrOCl2.8H2O and YCl3.6H2O were used as starting materials and NH4OH as a precipitation agent, various types of metal hydroxides were obtained by single precipitation(series A) and co-precipitation(series B) method at the pH condition between 7 and 11. Fine Al2O3-ZrO2 powders were prepared at optimum calcination condition and the effects of ZrO2 on microstructures and mechanical properties of Al2O3 were investigated. The composition of Al2O3/ZrO2 composites wax fixed as Al2O3-15 v/o ZrO2(＋3m/o Y2O3). ZrO2 limited the grain growth of Al2O3 and increased grain size homogeneity of Al2O3 more effectively than MgO.Flexural strength values in Al2O3 and Al2O3/ZrO2 composites were 340-430 MPa and 540-820 MPa, respectively, and the effect of strength improvement showed 20-50% by adding ZrO2 to Al2O3. Fracture toughness of Al2O3/ZrO2 composites was improved by stress-induced phase transformation of tetragonal ZrO2 and toughening effect by microcrack was not observed. Also, ZrO2 particles located at Al2O3 grain junction contributed to toughening, while spherical ZrO2 particles located within Al2O3 grain did not contribute to toughening. Weibull moduli of Al2O3 ceramics and Al2O3/ZrO2 composites of series A and series B were 4.34, 5.17 and 9.06, respectively. Above 0.5 of failure probability, strength values in Al2O3 ceramics and Al2O3/ZrO3 composites of series A and series B were above 400 MPa, 700 MPa and 650 MPa, respectively.

• 한국전기전자재료학회논문지
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• 제29권9호
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• pp.559-564
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• 2016

This study examined the malfunction mode of the HCMOS IC under narrow-band high-power electromagnetic wave. Magnetron is used to a narrow-band electromagnetic source. MFR (malfunction failure rate) was measured to investigate the HCMOS IC. In addition, we measured the resistance between specific pins of ICs, which are exposed and not exposed to the electromagnetic wave, respectively. As a test result of measurement, malfunction mode is shown in three steps. Flicker mode causing a flicker in LED connected to output pin of IC is dominant in more than 7.96 kV/m electric field. Self-reset mode causing a voltage drop to the input and output of IC during electromagnetic wave radiation is dominant in more than 9.1 kV/m electric field. Power-reset mode making a IC remained malfunction after electromagnetic radiation is dominant in more than 20.89 kV/m. As a measurement result of pin-to-pin resistance of IC, the differences between IC exposed to electromagnetic wave and normal IC were minor. However, the five in two hundred IC show a relatively low resistance. This is considered to be the result of the breakdown of pn junction when latch-up in CMOS occurred. Based on the results, the susceptibility of HCMOS IC can be applied to a basic database to IC protection and impact analysis of narrow-band high-power electromagnetic waves.

• Archives of Plastic Surgery
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• 제37권6호
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• pp.827-830
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• 2010

Purpose: Congenital spinal dermal sinus tract is a rare lesion connecting skin to deeper structures including neural tissue. It results from the failure of the neuroectoderm to separate from the cutaneous ectoderm in the third to fifth week of gestation. The common locations are the lumbosacral and occipital regions. Sometimes it extends to spinal canal. In this paper we report a case of congenital spinal dermal sinus tract in the coccyx. Methods: A 21-month-old male child born after an uncomplicated full-term pregnancy was admitted to our institute with a midline dermal sinus and a cartilaginous protrusion in the coccygeal region. There were no signs of infection. Neurologic examination showed no functional deficit in both lower limbs. He was treated with complete excision of the tract and an underlying accessory cartilage. Results: The spinal dermal sinus tract was extended from the skin to the coccyx. The stalk was loosely attached to the accessory cartilage of coccyx. At that point, it was dissected from the accessory cartilage and resected. The accessory cartilage was also resected at the bone and cartilage junction. During the follow-up period of 6 months, the wound healed well without any complication nor recurrence. Conclusion: Congenital spinal dermal sinus tract is known as a form of spinal dysraphism. In order to prevent complications, timely surgical intervention including complete resection of sinus tract with correction of associated abnormalities is of utmost importance.

• Journal of Korean Neurosurgical Society
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• 제64권3호
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• pp.386-405
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• 2021

Recent advancements in basic research on the process of secondary neurulation and increased clinical experience with caudal spinal anomalies with associated abnormalities in the surrounding and distal structures shed light on further understanding of the pathoembryogenesis of the lesions and led to the new classification of these dysraphic entities. We summarized the changing concepts of lesions developed from the disordered secondary neurulation shown during the last decade. In addition, we suggested our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase of development may cause corresponding lesions, such as failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neuro-cutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and regression failure spectrum of the medullary cord (thickened filum and filar cyst, low-lying conus, retained medullary cord, terminal myelocele and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association with the activity of caudal mesenchymal tissue in secondary neurulation involves a wider range of surrounding structures than in primary neurulation. Although the majority of the data are from animals, not from humans and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.

• Clinics in Shoulder and Elbow
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• 제25권1호
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• pp.5-14
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• 2022

Background: The purpose of this study was to verify the effect of protocatechuic acid (PCA) on tendon healing and fatty degeneration in a chronic rotator cuff model. Methods: Twenty-eight Sprague-Dawley male rats were randomly allocated into two groups: Saline+repair (SR) and PCA+repair (PR). The right shoulder was used for experimental interventions, and the left served as a control. PCA (30 mg/kg/day) was administered intraperitoneally at the site of infraspinatus tendon detachment in rats in the PR group, and the same volume of saline was administered to the same site in the SR group. The torn tendon was repaired 4 weeks after infraspinatus detachment. Four weeks after repair, hematoxylin and eosin (H&E), S100, and CD68 stains were performed to evaluate the degree of fatty degeneration and H&E and Masson trichrome stains were performed to assess tendon healing. Superoxide dismutase (SOD) was measured to test the efficacy of PCA as an antioxidant. Results: Results from histological evaluation indicated that SOD and CD68 levels at the musculotendinous region and collagen fiber parallel to the orientation at the tendon-to-bone junction were not significantly different between the SR and PR groups. The mean load-to-failure of the PR group (20.32±9.37 N) was higher than that of the SR group (16.44±6.90 N), although this difference was not statistically significant (p=0.395). The SOD activity in the operative side infraspinatus muscle of the PR group was higher than that of the SR group, but the difference was not statistically significant (p=0.053). Conclusions: The use of PCA could improve tendon healing and decrease fatty degeneration after rotator cuff repair.