• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.10-12
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• 1996

AlGaAs/GaAs Heterojunotion Bipolar Transistors (HBTs) with various emitter areas were fabricated and the device size dependence on the current gain was examined. With the different emitter areas, the passivated devices having the same peripheral length were fabricated and measured. The measured base current density in the Gummel plots shows an ideality factor of nearly 2. It is found that as the emitter area becomes small, the base current density with the ideality factor of 2 increases linearly, and as the emitter perimeter/area ratio becomes large, the surface recombination current density component increases. The current gain performance in AlGaAs/GaAs HBTs is mainly determined by either the larger emitter area or the smaller ratio of the emitter perimeter to the emitter area. These results will be compared with experimental works for GaInP/GaAs HBTs

• Investigative Magnetic Resonance Imaging
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• 제18권4호
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• pp.332-340
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• 2014

목적: 급성 뇌경색 환자의 자화율강조영상에서 보이는 관류 손상 부위의 현저한 유출정맥 저신호 강도 (PHSV)의 임상적 유용성을 평가하고자 하였다. 대상과 방법: 확산강조영상과 자화율강조영상을 포함한 뇌 자기공명영상을 시행한 급성 뇌경색 환자에서 추적 단면영상검사가 있는 환자 18명을 대상으로 뇌경색 및 주변부에서 PHSV 유무와 위치를 정성적으로 확인하였다. 자화율강조영상에서 PHSV와 정상 뇌피질 정맥의 신호강도차이 비율을 측정하였고, 주변 PHSV 유무와 추적검사에서 뇌경색 크기 변화의 상관관계를 분석하였다. 결과: 18명의 환자 중 10명의 환자가 추적검사에서 뇌경색이 진행하였고, 8명은 변화가 없었다. 뇌경색이 진행한 10명의 환자 중 9명에서 뇌경색 주변 PHSV가 관찰되었고, 새로 생긴 경색 부위는 초기 자화율강조영상에서 보였던 주변 PHSV 부위와 잘 일치하였다. 경색의 크기가 변화 없는 환자군과 비교하여 경색이 진행한 환자군에서 뇌경색 주변 PHSV의 빈도가 통계적으로 유의하게 높았고 (p=0.0001), 신호강도차이 비율도 유의하게 높았다 (p=0.006). 결론: 자화율강조영상에서 보이는 주변 PHSV는 반음영부 (penumbra)의 지표가 될수 있으며 급성 뇌경색 예후 예측에 이용될 수 있다.

• 대한화학회지
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• 제53권6호
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• pp.749-754
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• 2009

HEMA (2-hydroxyethyl methacrylate)는 친수성 안 의료용 소재로써 폭넓게 사용되고 있으며, 특히 소프트 콘택트렌즈 제조에 가장 많이 사용되는 재료중의 하나이다. 또한 산소투과율(Dk/t)은 콘택트렌즈 재료의 성능을 평가하기 위한 물리적 특성 중 매우 중요한 요소이다. 본 연구는 HEMA (2-hydroxyethyl methacrylate), MMA (methylmethacrylate), NVP (N-vinyl-pyrrolidone), 교차결합제인 EGDMA (ethylene glycol dimethacrylate)를사용하여 공중합 하였으며, 일반 콘택트렌즈와 칼라 콘택트렌즈를 제조하여 중심부와 주변부의 산소투과율을 polarographic method로 측정하였다. 실험 결과 polarographic method로 측정한 콘택트렌즈 주변부의 산소투과율 감소량은 40.77%에서 49.13%의 분포로 나타났으며, 칼라 콘택트렌즈는 염료에 기인된 영향으로 산소투과율의 감소량이 더 크게 측정되었다.

• The Korean Journal of Ecology
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• 제18권1호
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• pp.31-41
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• 1995

Floral analysis about vegetation of Kimpo landfills and its periphery region was carried out. The study area was defined to a square $(81km^2)$ of which center was located at 250m in front of Andongpo, Komdan-myon, Kimpo-gun in the northwest part of the Kyunggi Province. This study was accomplished by analyzing five qualitative traits such as ecological strategy, reproductive strategy, distribution type, native/foreign division and life-form throughout actual investigation of the flora. The flora was composed of 536 taxa which comprise 105 families, 343 genera, 458 species, 1 subaspecies, 70 varieties and 7 forms (including 92 species of horticultural plant). Lythrum salicaria community, Spiraea salicifolia community, ottelia alismoides community and woods of Alnus japonica were recorded ？ 새 retrictive distribution according to habitat characteristics. Owing to severe anthropogenic interferences such as construction of the Kimpo landfills in the study areas, a high proportion of ruderal plants and neophytes in the floral composition was recognized. The proportion of individual distribution type and therophyte was very high throughout whole study areas, and plant communities in the reclaimed areas were characterized by high proportion of phalanx plant species. Analysis of the correlations between meshes with ecological traits of plant species showed that Kimpo landfills and its periphery region was divided into two vegetation types, coastal type and inland type, as a result of possible saline effects.

• 국제초고층학회논문집
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• 제12권1호
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• pp.35-47
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• 2023

The transport system and its infrastructure are not only the fundamental means of sustaining the operation of contemporary cities, but also important drivers for the evolution of urban form. Rail transit, critical to improving the operational efficiency and optimizing the spatial layout in cities, is one of the critical conditions for high-density areas with limited land and concentrated resources to be compact to take on complex challenges. As a node element of infrastructure, rail transit entrances are the most important points connecting the rail transit system with urban space. Although influenced by urban form, their quantity and location also influence and shape the evolution of urban space form. Based on the development gap of high-density areas in various contexts, focusing on various rail transit stations in Asia, this research analyzes the correlation between rail transit entrances and peripheral high-density urban form in a delicate, dynamic and granular way. The research considers both horizontal and vertical perspectives, in combination with the urban evolution process in time series, to explore the development trend of high-density urban form in Asia from the aspect of correlation, and building a new foundation for research on urban form, suitable for different types of cities.

• Journal of Photoscience
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• 제9권2호
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• pp.491-493
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• 2002

Erythrodermic actinic reticuloid (EAR) is a photosensitive disorder characterized by dense lymphocytic infiltration in the sun-exposed areas and an increased number of atypical lymphocytes in the peripheral blood. We have reported 2 patients with EAR with circulating atypical lymphocytes and photosensitivity to both ultraviolet (UV) B and A. Although no clonal proliferation of T-cells was observed in the peripheral blood, CD8+ cells were increased in number in an oligoclonal fashion. A number of proliferating CD8+ cells were small, but most cells expressed bcl-2. These findings suggest EAR is a photosensitivity dermatitis characterized by the overspill of oligoclonal CD8+ lymphocytes responsive to UV irradiation.

• Toxicological Research
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• 제24권1호
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• pp.45-49
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• 2008

Formaldehyde has been identified as the most prevalent cause of sick building syndrome (SBS), which has become a major social problem, especially in developing urban areas. However, studies on the molecular mechanisms associated with formaldehyde toxicity have been limited, probably because it is difficult to relate the experimental results obtained from in vitro studies to human exposure in vivo. Using polymerase chain reaction-based suppression subtractive hybridization, we recently identified 27 different formaldehyde-inducible genes including platelet-derived growth factor receptor alpha gene (PDGFRA) and mouse double minute 2 (MDM2) gene which were increased significantly in both formaldehyde-exposed human trachea cells, 680.Tr, and rat tracheas. To establish a possible relationship between induction of these formaldehyde-inducible genes and symptoms of SBS, we examined expression levels of these genes in peripheral lymphocytes of residents of new apartments. Here, we report that the expression of PDGFRA and MDM2 transcripts was significantly higher in peripheral blood lymphocytes obtained from 15 residents in new buildings than in seven control individuals. Our results suggest that the elevated levels of PDGFRA and MDM2 may be associated with the formaldehyde-induced pathophysiology that is closely related with SBS, and that they deserve evaluation as potential biomarkers for formaldehyde intoxication.

• Journal of Chest Surgery
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• 제15권2호
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• pp.174-182
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• 1982

On the right lower lobe, scar carcinoma was presented in the Korean male, 56 years old, in February, 1982. His tumor is moderate differentiated adenocarcinoma. Scar carcinoma, a rare form of adenocarcinoma, is usually discovered on autopsy and rarely on surgical resected specimen and these tumors are found in areas of lung scarring. Most of the tumors are adenocarcinoma and found in the upper lobes and related to infarcts, tuberculous scars. No relationship between smoking and scar cancers were reported. The scar cancers are becoming more common. An apparent increase in scar cancer in the periphery of the lung was reported in America. Scar cancer does not present special clinical symptoms and signs, except manifestations of surrounded tissue compressed by large tumors in far advanced stage. These tumors progress slowly and metastasize late but characteristic signs on scar area of the lung can be discovered from the early stage on X-ray examination [solitary peripheral nodule and scar]. So careful study on chest x-ray film was acquired and if necessary, conservative resection of the lesion is indicated because the long term prognosis is not at all bad.

• 대한물리치료과학회지
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• 제6권4호
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• pp.187-199
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• 1999

Functional Electrical Stimulation (FES) is used for muscle reeducation, reduction of spasticity, delay of atrophy, and muscle strengthening. FES stronger stimulation than other forms of electrical stimulation. The efficacy of FES in improving function has been substantiated in the literature. Treatment programs employing FES - activation of muscular tissue through the intact peripheral nervous system - can be broken into five major categories, according to the goal of treatment. These broad areas would include the use of FES to: (1) a direct excitation onto the alpha motoneuron, through peripheral stimulation of the Ia myotatic sensory system and ascending afferent information, which will be integrated at conscious and subconscious level of the CNS. (2) The quality of a stimulated muscle contraction is determined by combination of many parameters, including stimulus amplitude, pulse duration, stimulus frequency, and duty cycle. (3) A unit that has a pulse duration between 200 and $400{\mu}sec$ will be more than adequate for FES applications. (4) The neuromuscular plasticity is critically important to return of function using muscle re-education and facilitation applications. (5) Prior to using FES as an electrical orthosis, the patient should build up endurance in the muscles to be stimu1ated during the gait cycle.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7645-7649
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• 2013

Background: Immune functions and their relation to prognosis in breast cancer patients have become areas of great interest in recent years. Correlations between survival outcomes and peripheral blood flow cytometry parameters are therefore of interest. Here we focused on patients with non-metastatic breast cancer (BC). Materials and Methods: A total of 29 patients with pathological confirmed breast carcinoma and flow cytometry data were assessed for overall survival (OS) and progression free survival (PFS). Results: The median age of the patients was 54 years (range, 29-83). Multivariate analysis revealed that OS was significantly associated with absolute cytotoxic T cell count (95%CI, coef 2.26, p=0.035), tumor size (95%CI, coef -14.5, p 0.004), chemotherapy (95%CI, coef 12.9, p 0.0001), MFI of CD4 (95%CI, coef -5.1, P 0.04), MFI of HLA DR (95%CI, coef -5.9, p 0.008) and tumor grade (95%CI, coef -13, P 0.049) with R-Sq(adj)=67%. Similar findings were obtained for PFS. Conclusions: OS and PFS were significantly associated with tumor grade, tumor size, chemotherapy, MFI of CD4, HLA DR and absolute cytotoxic T cell count. The study revealed that MFI of basic CD markers and absolute cytotoxic T cell number may be a prognostic factors in women with non-metastatic BC.