• Environmental Engineering Research
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• 제25권3호
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• pp.439-445
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• 2020

In the estimation of the aerosol single fiber efficiency using fibrous filters, there is a size range, where the particles penetrate most effectively through the fibrous collectors, and corresponding minimum single fiber efficiency. For small particles in which the diffusion mechanism is dominant, the Cunningham slip correction factor (C_c) affects the single fiber efficiency and the most penetrating particle size (MPPS). Therefore, for accurate estimation, C_c is essential to be considered. However, many previous studies have neglected this factor because of its complexity and the associated difficulty in deriving the appropriate parameterization particularly for the MPPS. In this study, the expression for the MPPS, and the corresponding expression for the minimum single fiber efficiency are analytically derived, and the effects of C_c are determined. In order to accommodate the slip factor for all particle-size ranges, C_c is simplified and modified. Overall, the obtained analytical expression for the MPPS is in a good agreement with the exact solution.

• Safety and Health at Work
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• 제9권3호
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• pp.360-364
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• 2018

Asbestos has been banned in many countries but many countries, including developing countries, are still using asbestos or materials containing asbestos. Substitute materials have been studied and developed over a long period of time because of the hazards of asbestos, and many people have recently shown interest in the hazards of substitute materials. However, comprehensive information about the types of asbestos substitutes, their use and health hazards, and references for the protection for the health of workers is limited. The purpose of this study is to provide people in the related industries with information on the types and health hazards of fibrous materials that can be used as asbestos substitutes. According to the patent resources from the United States and Europe, fibrous materials have been used to develop asbestos-free products since before 1980. Recently, the health hazards of asbestos substitutes have been assessed and many additional researches are required. However, only some of the substitute materials have been assessed for health hazards, and health hazard data has not been sufficient in many cases. Therefore, efforts should be made to minimize workers' exposure to substitute materials that do not contain asbestos.

• Journal of Chest Surgery
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• 제47권3호
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• pp.283-286
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• 2014

A 61-year-old man was diagnosed with aortic stenoinsufficiency with periannular abscess, which involved the aortic root of noncoronary sinus (NCS) that invaded down to the central fibrous body, whole membranous septum, mitral valve (MV), and tricuspid valve (TV). The open complete debridement was executed from the aortic annulus at NCS down to the central fibrous body and annulus of the MV and the TV, followed by the left ventricular outflow tract reconstruction with implantation of a mechanical aortic valve by using a leaflet of the half-folded elliptical bovine pericardial patch. Another leaflet of this patch was used for the repair of the right atrial wall with a defect and the TV.

• Investigative Magnetic Resonance Imaging
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• 제25권4호
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• pp.338-344
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• 2021

Solitary fibrous tumors (SFT) are rare mesenchymal tumors that most commonly develop in the pleura; they rarely involve the diaphragm. MRI has not been widely used to evaluate SFTs of the thoracic cavity, though it may be highly useful in assessing local invasion, predicting malignant potential, and helping in the differential diagnosis. However, MRI findings of malignant SFTs of the diaphragmatic pleura have been described in only two cases. We report a rare case of a malignant solitary fibrous tumor of the diaphragmatic pleura in an 82-year-old man. We describe the clinical and characteristic imaging features, including computed tomography, conventional MRI, and diffusion-weighted imaging. Contrast-enhanced MRI is more accurate than is CT in identifying the origin of SFTs, predicting whether they ae benign or malignant, and assessing local invasion. This imaging modality proved helpful in deciding on the treatment strategy for these rare tumors.

• 한국재료학회지
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• 제32권2호
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• pp.107-113
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• 2022

Fibrous supercapacitors (FSs), owing to their high power density, good safety characteristic, and high flexibility, have recently been in the spotlight as energy storage devices for wearable electronics. However, despite these advantages, FCs face many challenges related to their active material of carbon fiber (CF). CF has low surface area and poor wettability between electrode and electrolyte, which result in low capacitance and poor long-term stability at high current densities. To overcome these limits, fibrous supercapacitors made using surface-activated CF (FS-SACF) are here suggested; these materials have improved specific surface area and better wettability, obtained by introducing porous structure and oxygen-containing functional groups on the CF surface, respectively, through surface engineering. The FS-SACF shows an improved ion diffusion coefficient and better electrochemical performance, including high specific capacity of 223.6 mF cm^-2 at current density of 10 ㎂ cm^-2, high-rate performance of 171.2 mF cm^-2 at current density of 50.0 ㎂ cm^-2, and remarkable, ultrafast cycling stability (96.2 % after 1,000 cycles at current density of 250.0 ㎂ cm^-2). The excellent electrochemical performance is definitely due to the effects of surface functionalization on CF, leading to improved specific surface area and superior ion diffusion capability.

• 대한영상의학회지
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• 제83권2호
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• pp.420-424
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• 2022

중이의 영유아 섬유성 과오종은 매우 드물다. 저자들은 26개월 남아의 중이에서 진단된 사례를 영상의학적 소견을 중심으로 보고하고자 한다. CT 영상에서는 귓속뼈의 파괴가 없었으며 MRI에서는 지방과 섬유성 조직과 유사한 신호 강도를 보였다. 수술 후 조직학적 검사에서 영유아 섬유성 과오종으로 진단받았다. 중이의 영유아 섬유성 과오종은 드물지만, 유년기에 중이에서 관찰되는 종괴의 감별진단에 포함되어야 한다.

• 대한영상의학회지
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• 제82권5호
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• pp.1346-1351
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• 2021

Mazabraud 증후군은 다골성 섬유성 이형성과 근육 내 점액종이 동반되는 매우 드문 양성 질환이다. 섬유성 이형성에서 악성 변환이 일어나는 경우는 약 1%로 알려져 있고, Mazabraud 증후군의 섬유성 이형성에서 발생한 골육종으로 악성 변환에 대한 보고는 아직까지 전 세계에 8예에 불과하다. 저자들은 Mazabraud 증후군 환자에서 섬유성 이형성이 있었던 경골에 골육종이 발생한 증례를 경험하였기에 영상 소견을 중심으로 대한민국에서 처음으로 보고한다.

• 한국미생물·생명공학회지
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• 제51권4호
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• pp.457-464
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• 2023

Proteolytic enzymes produced by filamentous fungi can degrade various fibrous and globular proteins along with other metabolites that may also find application in biotechnology. In this study, the effect of proteolytic enzymes of 22 Aspergillus strains on various proteins was investigated using protein-containing diagnostic media. Subsequently, a new parameter estimating secreted proteinases specificity towards fibrous or globular proteins without its advanced biochemical research - index of severity of proteolytic action (ISPA) - was suggested. This index determines mycozymes specificity in following manner: its value increases with greater affinity to fibrous proteins, decreases if there is higher affinity to globular proteins. ISPA value was the lowest (0.52) for Aspergillus domesticus, indicating the highest specificity to globular proteins, the highest one (1.26) for A. glaucus, whose proteinases best hydrolyzed fibrous proteins. However, the highest overall proteolytic potential was observed for Aspergillus melleus. The ability to produce acid, alkali and extracellular pigments was evaluated for all isolated strains as well.

• 치과방사선
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• 제29권2호
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• pp.533-547
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• 1999

Malignant fibrous histiocytoma is one of the most common soft tissue sarcomas in late adult life. but its incidence in oral and maxillofacial region is extremely rare. We report a case of malignant fibrous histiocytoma which occurred in the infratemporal fossa. Conventional radiograph of this case showed an ill-defined radiolucent lesion in the alveolar bone of the right maxillary first molar area. the lateral wall of the maxillary sinus. and the ascending ramus of mandible. MRI demonstrated a well defined mass of intermediate signal intensitiy in Tl weighted images but T2 weighted images showed two distinctive regions of different characteristics. Upper portion of the lesion was of hyperintense signal but (at) lower portion, the signal intensity decreased clearly, which might mean that this lesion(mass) is composed of two different subtypes though it couldn't be confirmed by histopathological examination. Biopsy was taken the lesion as only in the soft tissue of the maxillary posterior alveolar region and confirmed the storiform-pleomorphic type of malignant fibrous histiocytoma. Histopathological subtype was well consistent with the relatively aggressive imaging findings of that region. We expect more detailed analysis of the nature of malignant fibrous histiocytoma with improvement of the imaging modality and the identification of the relationship between diagnostic imaging and histopathologic findings.

• Journal of Korean Dental Science
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• 제6권1호
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• pp.34-40
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• 2013

Fibrous dysplasia is a benign fi bro-osseous lesion wherein normal bone is replaced with an excessive proliferation of cellular fibrous connective tissue intermixed with irregular bony trabeculae. Fibro-osseous lesions like fibrous dysplasia are often associated with non-epithelial cysts, such as simple bone cyst. The etiologic and pathogenic relationships between fi brous dysplasia and simple bone cyst have not been conclusively established. Nonetheless, the mechanism of cyst formation in fibro-osseous lesion associated with simple bone cyst can be said to differ from that of the typical simple bone cyst of the jaws. This article reports a case of bilateral lesions including fi brous dysplasia and simple bone cyst on each site and reviews the pathogenesis of cyst formation in the fibro-osseous lesion.