• 가정과삶의질연구
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• 제29권6호
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• pp.9-25
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• 2011

This study was performed to explore the factors that affect debt-use intention of young defaulters. In addition, this study compares three models that predict the intention to use debt by young defaulters: the theory of reasoned action and two variations of it. Specifically, this study proposes an extended theory of reasoned action by introducing Ao in place of the cognitive structure in the theory of reasoned action. In addition, this study proposes Ao as an independent variable that acts on BI rather than a dependent variable. Self-administered questionnaires were completed by 196 young defaulters attending a credit management education session held by the Credit Counseling & Recovery Service in Kwang-ju, Korea. Based on the study, the conclusions are as follows: the extended theory of reasoned action as proposed in this article most suitably explained the intention to use debt by young defaulters. It was also found that young defaulters were affected by attitudes toward debt, attitudes toward using debt, and subjective norms. It is therefore suggested that an attitudinal message would change the behavior effectively for young defaulters. The findings appeared to support the usefulness of the extended theory of reasoned action and the role of Ao as an independent variable as proposed in this article to explain the intention to use debt by young defaulters. These findings have an important theoretical meaning in that they modify two existing attitude theories in the context of consumer behavior.

• Tuberculosis and Respiratory Diseases
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• 제87권1호
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• pp.52-64
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• 2024

Chronic respiratory diseases such as idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, and respiratory infections injure the alveoli; the damage evoked is mostly irreversible and occasionally leads to death. Achieving a detailed understanding of the pathogenesis of these fatal respiratory diseases has been hampered by limited access to human alveolar tissue and the differences between mice and humans. Thus, the development of human alveolar organoid (AO) models that mimic in vivo physiology and pathophysiology has gained tremendous attention over the last decade. In recent years, human pluripotent stem cells (hPSCs) have been successfully employed to generate several types of organoids representing different respiratory compartments, including alveolar regions. However, despite continued advances in three-dimensional culture techniques and single-cell genomics, there is still a profound need to improve the cellular heterogeneity and maturity of AOs to recapitulate the key histological and functional features of in vivo alveolar tissue. In particular, the incorporation of immune cells such as macrophages into hPSC-AO systems is crucial for disease modeling and subsequent drug screening. In this review, we summarize current methods for differentiating alveolar epithelial cells from hPSCs followed by AO generation and their applications in disease modeling, drug testing, and toxicity evaluation. In addition, we review how current hPSC-AOs closely resemble in vivo alveoli in terms of phenotype, cellular heterogeneity, and maturity.

• 한국광학회지
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• 제33권4호
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• pp.167-176
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• 2022

적응 광학(adaptive optics, AO)은 대기 외란을 실시간으로 보정하는 기술을 말하고, 이러한 적응광학의 효율적 개발을 위하여, 다양한 성능 예측 기법을 도입하여 적응광학이 적용된 시스템 성능 예측을 실시한다. 적응광학의 성능 예측 기법으로 자주 사용되는 기법으로는 통계분석, 전산모사 및 광학 벤치 테스트가 있다. 통계분석에서는 적응광학 시스템을 통계 분석 모델로 가정하여 오차값(분산)의 제곱을 전부 합쳐 스트렐비를 간단하게 추정한다. 다만, 하위 변수 간의 상관 관계는 무시되어 이에 따른 추정의 오류는 존재한다. 다음으로, 전산모사는 대기 난류, 파면센서, 변형거울, 폐쇄 루프 등 모든 구성요소를 가능한 한 실제와 가깝게 모델링하고, 시간 흐름에 따른 적응광학 시스템의 변화를 모두 구현하여 성능 예측을 수행한다. 다만, 전산모사 모델과 현실 사이에는 여전히 일부 차이가 있어, 광학 벤치 테스트를 통하여 시스템 성능을 확인한다. 최근 국내에서 개발된 변형 거울을 적용한 1.6 m 지상 망원경용 적응광학 시스템을 개발 중에 있어, 이에 적용 가능한 적응광학 시스템을 통하여 성능 예측 기법이 요구되며 동시에 성능 예측 기법의 비교를 진행하고자 한다. 앞서 언급된 통계분석 및 전산모사를 이용하여 시스템 성능 예측을 수행하였으며, 성능 예측의 분석을 위해 각각의 성능 예측 기법의 망원경 및 적응광학 시스템 모델링 과정 및 결과를 제시하였다. 이때 성능 예측을 위한 대기 조건으로는 보현산 관측 중앙값(median)을 적용하였다. 그 결과 통계 분석 방법의 경우 평균 스트렐 비가 0.31이 도출됨을 확인하였고, 전산모사 방법의 경우 평균 스트렐 비가 0.32를 가짐을 확인함으로써 두 방법에 의한 예측이 거의 유사함을 확인할 수 있었다. 추가적으로, 전산모사의 경우 해석 결과의 신뢰성을 확보하기 위하여, 모사 시간이 대기 임계 시간 상수의 약 240배인 0.9초 이상 수행되어야 함을 알 수 있었다.

• 한국전자파학회논문지
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• 제21권2호
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• pp.179-187
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• 2010

차세대 이동 통신 시스템에서는 높은 주파수 대역, 광대역, 다중 안테나(MIMO antenna)의 사용이 예상된다. 또한 무선 통신의 급격한 수요와 이동 통신 서비스의 폭발적인 증가로 인해 차세대 이동 통신 시스템의 최적화를 위한 검증 모델 개발 연구가 필요하다. 기존 MIMO 채널 모델의 경우 도심, 부도심, 시골, 개활지 등으로 포괄적으로 전파 환경을 분류하여 연구를 수행하였으나, 이러한 접근 방법은 예를 들어 도심 환경 내에서도 다양한 morphology가 존재할 수 있기 때문에 모델링 정확도 측면에서 취약성을 가질 수 있다. 본 논문에서는 path morphology 개념을 도입하여 전파 환경을 송 수신기 사이의 건물의 높이, 밀집도 등을 고려하여 세부적으로 분류하는 방법을 제안하였다. 광선 추적(ray tracing) 기법을 이용하여 각 환경별 delay spread(DS), AoD와 AoA의 angular spread(AS)를 분석하고, 이를 바탕으로 국내 환경에 적합한 MIMO 채널 모델을 제시하였다.

• 해양환경안전학회지
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• 제20권5호
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• pp.571-578
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• 2014

남 북한간 정전협정시 해양경계를 정하지 못했으며, 주변국과 관할해역 경계가 명확하지 않다. 유엔군사령부는 6.25전쟁 이후 정전협정 준수를 위해 북방한계선과 작전구역을 설정해 해 공군 세력의 활동을 통제했고, 우리나라는 작전구역 내에서 북한선박의 통항을 통제해 왔다. 작전구역 내에서 제3국 선박은 항해의 자유를 향유하지만, 북한선박은 교전국으로서 통항이 통제되는 특수한 해양 제도가 유지되고 있다. 그러나, 작전구역이 설정된 이후 유엔해양법협약 발효, 남 북한의 유엔 가입 등 변화가 지속되고 갈등요인이 있어 작전구역의 지리적 범위를 보완할 필요가 있다. 또한 해군의 기능적 역량 강화를 위해 해군함정에게 북한선박 통제를 법적으로 보장하는 조치가 요구된다. 본 논문에서는 6.25 전쟁 이후 한반도 주변해역에서 북한선박을 통제하여 온 실례와 북한선박 통항통제 제도에대한 개선방안을 살펴보았다.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1262-1270
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• 2007

Some hot springs located in the west of Turkey were investigated with respect to the presence of thermophilic microorganisms. Based on phenotyping characteristics and 16S rRNA gene sequence analysis, 16 of the isolates belonged to the genus Geobacillus and grew optimally at about $60^{\circ}C$ on nutrient agar. 16S rRNA gene sequence analysis showed that these isolates resembled Geobacillus species by ${\ge}97%$, but SDS-PAGE profiles of these 16 isolates differ from some of the other species of the genus Geobacillus. However, it is also known that analysis of 16S rRNA gene sequences may be insufficient to distinguish between some species. It is proposed that recN sequence comparisons could accurately measure genome similarities for the Geobacillus genus. Based on recN sequence analysis, isolates 11, IT3, and 12 are strains of G stearothermophilus; isolate 14.3 is a strain of G thermodenitrificans; isolates 9.1, IT4.1, and 4.5 are uncertain and it is required to make further analysis. The presence of xylanase and arabinofuranosidase activities, and their optimum temperature and pH were also investigated. These results showed that 7 of the strains have both xylanase and arabinofuranosidase activities, 4 of them has only xylanase, and the remaning 5 strains have neither of these activities. The isolates 9.1, 7.1, and 3.3 have the highest temperature optima ($80^{\circ}C$), and 7.2, 9.1, AO4, 9.2, and AO17 have the highest pH optima (pH 8) of xylanase. Isolates 7.2, AO4, AC15, and 12 have optimum arabinofuranosidase activities at $75^{\circ}C$, and only isolate AC15 has the lowest pH of 5.5.

• Journal of Nutrition and Health
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• 제36권8호
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• pp.819-827
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• 2003

Linoleic acid [LA; 18: 2 (n-6)] is the most abundant polyunsaturated fatty acid in human skin. The exclusion of LA from diet induces epidermal hyperproliferation, which is reversible by the inclusion of LA in diet, and hence, LA is heralded as an essential fatty acid (EFA). Since safflower oil (SO) has been widely recognized as the major dietary source of LA and Arctii Fructus (Arctium lappa L.) is recently reported to contain high level of LA, we compared the antiproliferative effects of SO and Arctii Fructus in this study. Epidermal hyperproliferation was induced in guinea pigs by hydrogenated coconut oil (HCO) diet for 8 wk. During following 2 wk, EFA deficient guinea pigs were fed diets of safflower oil (group HS), water extract of Arctii Fructus (group AW) or organic extract of Arctii Fructus (group AO). Normal control group was fed SO containing diet (group SO) and EFA deficient group was fed HCO containing diet (group HCO) for 10 wk. Epidermal hyperproliferation was reversed in groups AO (55.9% of group HCO) and HS(74.1% of group HCO). However, the thymidine incorporation into epidermal DNA of group HS was greater than of normal control group SO. Epidermal hyperproliferation was not reversed in group AW. The accumulations of LA into phospholipids and ceramides, and of 13-hydroxyoctadecadienoic acid (13-HODE), the potent antiproliferative metabolite of LA in the epidermis of group AO were greater than of group HS. In contrast, the de novo synthesis of ceramides, the major lipids maintaining epidermal barrier, did not differ between all of groups. Together, our data demonstrate that organic extract of Arctii Fructus is more prominent than safflower oil in reversing epidermal hyperproliferation by inducing the higher accumulations of LA and 13-HODE in the epidermis of guinea pigs.

• Food Science and Biotechnology
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• 제15권2호
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• pp.202-206
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• 2006

The oxidation stability of fish oil containing omega-3 polyunsaturated fatty acids (PUFAs), which is very susceptible to oxidative deterioration, needs to be improved before it can be successfully applied to functional foods. The antioxidant activities of 17 species of materials in anchovy oil (AO) were compared and a potent antioxidant was determined to improve the shelf-life of refined AO. Antioxidant activities of the 0.05% (w/w) materials in AO were compared against control during storage at $30^{\circ}C$ for 10 days. While no antioxidant effect was shown in alpha tocopherol against control, 3 species of grapefruit seed extracts (GSEs), astaxanthin (AX), soybean lecithin, and green tea extract showed good antioxidant activities. Especially, GSE B, GSE C, and AX showed significantly high peroxide inhibitory activities (PIAs) of $16.2{\pm}2.1$, $20.{\pm}3.5$, and $17.7{\pm}3.5%$, respectively, after the 4th day (p<0.01). Radical scavenging activities (RSAs) of GSE B, GSE C, and AX were $85.1{\pm}0.8$, $95.3{\pm}0.3$, and $85.9{\pm}0.8%$, respectively. Correlation between PIAs and RSAs was high ($R^2=0.926$) in GSE B, GSE C, and AX. Therefore, we concluded that one of the main antioxidative mechanisms of GSEs and AX must operate through an RSA pathway. The $RC_{50}$ (concentration required for 50% reduction of 1,1-diphenyl-2-picryl-hydrazyl, DPPH) of GSE C was $258\;{\mu}g/mL$.

• Clinical and Experimental Pediatrics
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• 제59권4호
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• pp.183-189
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• 2016

Purpose: This study aimed to evaluate the correlation, according to postnatal age, between plasma B-type natriuretic peptide (BNP) levels and echocardiographic parameters for the assessment of patent ductus arteriosus (PDA) in preterm infants with respiratory distress. Methods: We enrolled 42 preterm infants with respiratory distress who underwent serial echocardiographic evaluation with simultaneous plasma BNP measurements until ductal closure. The correlations between BNP levels and the following 4 representative echocardiographic parameters were studied: diameter of the ductus arteriosus (DA), ratio of the left atrial diameter to the aortic diameter (LA/Ao), ratio of the PDA diameter to the infant's left pulmonary artery diameter (PDA/LPA), and the antegrade diastolic flow of LPA (DFLPA). Results: BNP levels were significantly correlated to the magnitude of the ductal shunt, comprising the DA diameter, PDA/LPA ratio, LA/Ao ratio, and antegrade DFLPA for the overall study period. The earliest significant correlation, starting from postnatal day 2, was observed between the LA/Ao ratio and BNP levels. The PDA/LPA ratio and the antegrade DFLPA showed significant correlations with BNP levels postnatal day 3 onward, and with the DA diameter, postnatal day 5 onward. Conclusion: BNP levels and echocardiographic parameters showed a positive correlation, but the significance of the correlations differed according to the postnatal age, especially during the first few days of life.

• 멤브레인
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• 제33권2호
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• pp.61-69
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• 2023

최근 COVID-19로 인해 증가한 급성 폐부전 중증환자 치료를 위한 인공폐 기술의 필요성이 부각되었다. 또한, 빠르게 진행되고 있는 인구고령화는 인공장기(artificial organ, AO) 기술에 대한 높은 수요를 불가피하게 만들고 있다. 분리막은폐, 신장, 간 및 췌장을 포함한 많은 AO 기기의 핵심 부품이다. 특히 인공폐(artificial lung, AL) 기술은 지난 50년간 빠르게 발전해왔지만, 장기부전 환자의 생존율은 50% 내외로 여전히 낮은 편이다. 현재 대부분의 AL 관련문헌은 임상결과에 집중되어 있으며, AL 분리막의 개발연구는 매우 부족한 편이다. 이에 대한 원인 중 하나는 AL 기술이 생명공학을 포함하여 고분자 화학 및 분리공정 기술을 아우르는 융합적 기술개발을 요구하기 때문인 것으로 판단된다. 본 총설에서는 헬스케어산업에서 AL 분리막 기술의 역할과 기술개발이 필요한 난제들을 정리하였다. 특히, 분리막 소재의 혈액적합성, 분리성능, 모듈 디자인 및 공정 구성 측면에서 다양한 연구개발이 필요하다는 부분을 강조하고자 한다.