• 대한화장품학회지
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• 제30권3호
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• pp.345-352
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• 2004

아토피 피부염을 설명하는 데는 두 가지 패러다임이 있는데, 첫 번째는 outside-inside paradigm이고 두 번째는 inside-ouside paradigm이다. Outside-inside paradigm에 의하면 아토피 피부염을 치료하기 위한 가장 좋은 방법은 피부 장벽 기능을 회복시키는 것이다. 장벽 기능은 각질층의 특징적인 구조에 의해 유지되는데, 각질층은 층상구조의 inter-cellular lipids와 corneocyte로 구성되어 있다. 아토피 피부염 환자, 층판상 어린선 환자의 각질층 내 층상구조는 hexagonal 구조가 많이 존재하고 있음을 보였으며, 이는 Ceramide 1 타입과 long chain fatty acid의 감소 때문이라고 보여진다. 이러한 이유에서 라멜라구조를 가지며 intercellular long periodicity phase 기능을 복원할 수 있는 보습제는 각질층의 intercellular lipid의 층상구조를 복원시킬 수 있을 것이다. 또한 세라마이드와 유사세라마이드를 함유한 보습제는 손상된 피부장벽, 피부질환, 아토피 피부염을 위한 유용한 치료제로 사용할 수 있다. Inside-outside paradigm에 따르면, 아토피 피부염 등이 보조 T cell, lg E, eosinophil 등을 포함한 면역반응과 관계되는데, 특히 Th1/Th2 imbalance의 복원이 아토피 피부염을 치료하는데 효과적일 것이다. 현재 여러 종류의 면역억제제가 소개되고 있지만, 이들은 고유 면역기능을 감소시킬 우려를 가지고 있다. 따라서, 세라마이드 대사산물인 SPC와 S1P는 면역조절 기능 및 상처치유의 기능을 가짐으로써 향후 관심이 집중될 것이다.

• 대한화장품학회지
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• 제49권1호
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• pp.59-65
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• 2023

사이자이지움 클래비플로룸(Syzygium claviflorum (Roxb.) Wall. ex A.M. Cowan & Cowan, S. claviflorum)의 추출물 (잎, 줄기, 열매, 꽃)의 화장품 소재로써 활용되기 위한 생리활성 능력을 검증하였다. 첫번째로, S. claviflorum 추출물은 DPPH와 ABTS assay법을 이용한 항산화 실험에서 다양한 농도로 처리한 결과, 약 80% 이상의 자유 라디칼을 제거하였다. 사람 피부 표피 각질형성세포(human epidermal keratinocytes)를 이용한 세포독성 실험에서는 S. claviflorum 추출물은 낮은 세포독성을 보였다. 또한, S. claviflorum 추출물은 각질형성세포의 분화인자 (keratin (KRT)1, KRT2, KRT9, KRT10)와 피부장벽의 기능 유지에 중요한 involucrin (IVL), loricrin (LOR), filaggrin (FLG)과 claudin1 (CLDN1) 유전자의 발현을 현저히 증가시켰다. 특히, in vitro 아토피 피부염 실험에서 interleukin (IL)-4/IL-13에 의해 억제된 FLG 단백질 발현이 S. claviflorum 추출물에 의해 회복되었다. 따라서, 뛰어난 항산화 효능과 피부장벽 개선 기능을 보유한 S. claviflorum 추출물은 향후 아토피 피부염 치료제 및 화장품 개발에 유용한 소재가 될 것이다.

• 한국포장학회지
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• 제29권1호
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• pp.43-49
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• 2023

본 연구에서는 CasNa/CL의 물리적 특성을 개선하기 위하여 BN을 충진제로 활용하여 CasNa/CL/BN코팅제 및 코팅지들을 제조하였다. BN의 함량변화에 따라 제조한 CasNa/CL코팅지와 CasNa/CL/BN코팅지들의 화학적 및 형태학적 특성을 분석하였고, 기계적강도, 수증기차단특성, 표면특성, 항산화특성에 대한 분석을 통해 포장소재로써 적용 가능성을 확인하였다. SEM분석결과, CasNa/CL코팅지 표면에서 핀홀 현상이 발생하는 것을 확인하였다. 하지만, BN함량이 증가함에 따라 핀홀 현상은 감소되는 경향을 보였고 표면거칠기는 증가되는 경향을 확인할 수 있었다. BN 함량이 증가함에 따라 CasNa/CL/BN코팅지들의 연신률 및 수증기차단성이 개선되는 것을 확인할 수 있었다. BN함량 증가에도 불구하고 CasNa/CL/BN코팅지들의 항산화특성은 CasNa/CL코팅지와 유사한 경향을 보임을 확인하였다. 자연유래소재인 CasNa, CL 및 BN을 활용한 코팅지의 경우 친환경 포장소재로써 활용이 가능할 것으로 판단되지만, CL 및 BN과 CasNa와의 혼화성 및 분산성 개선 방안에 대한 추가적인 연구가 필요함을 확인하였다.

• Journal of Animal Science and Technology
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• 제65권5호
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• pp.1040-1052
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• 2023

The objective of this study was to investigate the protective effects of functional nutrients including various functional amino acids, vitamins, and minerals on chicken intestinal epithelial cells (cIECs) treated with oxidative stress. The cIECs were isolated from specific pathogen free eggs. Cells were exposed to 0 mM supplement (control), 20 mM threonine (Thr), 0.4 mM tryptophan (Trp), 1 mM glycine (Gly), 10 μM vitamin C (VC), 40 μM vitamin E (VE), 5 μM vitamin A (VA), 34 μM chromium (Cr), 0.42 μM selenium (Se), and 50 μM zinc (Zn) for 24 h with 6 replicates for each treatment. After 24 h, cells were further incubated with fresh culture medium (positive control, PC) or 1 mM H₂O₂ with different supplements (negative control, NC and each treatment). Oxidative stress was measured by cell proliferation, whereas tight junction barrier function was analyzed by fluorescein isothiocyanate (FITC)-dextran permeability and transepithelial electrical resistance (TEER). Results indicated that cell viability and TEER values were less (p < 0.05) in NC treatments with oxidative stress than in PC treatments. In addition, FITC-dextran values were greater (p < 0.05) in NC treatments with oxidative stress than in PC treatments. The supplementations of Thr, Trp, Gly, VC, and VE in cells treated with H₂O₂ showed greater (p < 0.05) cell viability than the supplementation of VA, Cr, Se, and Zn. The supplementations of Trp, Gly, VC, and Se in cells treated with H₂O₂ showed the least (p < 0.05) cellular permeability. In addition, the supplementation of Thr, VE, VA, Cr, and Zn in cells treated with H₂O₂ decreased (p < 0.05) cellular permeability. At 48 h, the supplementations of Thr, Trp, and Gly in cells treated with H₂O₂ showed the greatest (p < 0.05) TEER values among all treatments, and the supplementations of VC and VE in cells treated with H₂O₂ showed greater (p < 0.05) TEER values than the supplementations of VA, Cr, Se, and Zn in cells treated with H₂O₂. In conclusion, Thr, Trp, Gly, and VC supplements were effective in improving cell viability and intestinal barrier function of cIECs exposed to oxidative stress.

• Corrosion Science and Technology
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• 제6권4호
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• pp.206-210
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• 2007

Aerospace aluminum alloys such as Al alloy 2024-T3 and 7075-T6 are subject to localized corrosion due the existence of intermetallics containing Cu, Mg or Zn. Chromate is currently widely used in the aerospace industry as the corrosion inhibitor for these alloys. However, chromate needs to be replaced due to its strong carcinogenicity. In this study, an extensive pigment screening has been performed to find replacements for chromates. Different categories of inhibitors were evaluated by immersion tests, DC polarization tests and other methods. Phosphates, zinc salts, cerium salts, vanadates and benzotriazole were found to be effective inhibitors for AA7075. Among those inhibitors, zinc phosphate was found to be the most effective in our novel, silane-based, one-step aqueous primer system. The performance of this primer is comparable to that of currently used chromate primers in accelerated corrosion tests, while it is completely chromate-free and its VOC is about 80% less than that of current primers. Studies by SEM/EDS showed that the unique structure of the superprimer accounts for the strong anti-corrosion performance of the zinc phosphate pigment. The self-assembled stratified double-layer structure of the superprimer is characterized by a less-penetrable hydrophobic layer at the top and a hydrophilic layer accommodating the inhibitors underneath. The top layer functions as the physical barrier against water ingress, while the lower layer functions as a reservoirfor the inhibitor, which is leached out only if the coating is damaged by a scratch or scribe. The presence of a silane in the primer further improves the adhesion and anti-corrosion performance of the primer.

• 한국자기학회지
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• 제12권6호
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• pp.201-205
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• 2002

경사형 모서리접합을 이용한 터널링 자기저항(tunneling magnetoresistance; TMR) 특성을 연구하였다. 박막 증착과 식각은 스퍼터링과 사이크로트론 전자공명 (electron cyclotron resonance; ECR) 장치를 각각 사용하였다. Si$_3$N$_4$ 장벽층을 이용한 접합의 다층구조는 NiO(60)/Co(10)/NiO(60)/Si$_3$N$_4$(2-6)/NiFe(10) (nm)이었다. 상하부 반강자성체 NiO에 삽입된 wedged 형태의 고정층 Co와 장벽층 Si$_3$N$_4$위에 경사진 비대칭 구조에서 자유층 NiFe간의 접합에서 일어나는 특이한 스핀의존 터널링 현상이 관찰되었다. 외부자장이 0Oe일 때와 접합경계선에 수직방향으로 90Oe일 때 측정한 접합소자의 전류전압특성 곡선이 현저하게 구별되어 나타났다. TMR의 인가 전압의존성은 $\pm$10 V일 때도 약 -10%을 유지하는 매우 안정된 자기저항 특성을 보여주었다.

• 가정과삶의질연구
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• 제23권2호
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• pp.11-22
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• 2005

The purpose of this study is 1) to clarify that the house is no long the safe place through the cases of the senior safety accidents and to argue the need for housing repair and 2) to present the minimum standards for housing repair by comparing the cases here as well as the abroad and to back up the standards with the current senior housing environment 300 people at least 60 years old living in Seoul$\cdot$Metropolitan area were interviewed using the structured questionnaire. As the result, the following conclusions were made: 1. There was high accident rates of the senior residents due to physical deficits within the house, causing excessive medical cost and decreased housing satisfaction. This problem can be sufficiently prevented by housing repair which can not only solve the safety problem but also support self sufficient living for the senior residents. 2. Proper housing repair required the architectural know how as well as the expertise knowledge of the physical characteristics of the senior people. Therefore, it is essential to secure the professional (i.e., occupational therapist) who can analyze the needs of the senior residents and evaluate and/or predict the obstacles during repair. Furthermore, development and distribution of the standardized manual are also needed. 3. The minimum standard for housing repair could be approached in view of 'barrier-free' concept. First, the bumps should be removed, slippery prevented, and safety grab-bar installed for safety. Second, the entrance should be widened and the bathroom and kitchen restructured to support for the senior residents' self sufficiency. To make housing repair policy more efficient, the legal basis is required. It can be incorporated into the existing senior citizens 'Welfare Act' or the 'Senior Residents Medical Insurance' which will be effective starting in 2007.

• 대한간호학회지
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• 제31권1호
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• pp.107-125
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• 2001

This study was designed to construct a structural model for quality of life of chronic gastric disease. The hypothetical model was developed based on the literature review and Pender's health promotion model. Data were collected by questionnaires from 459 patients with chronic gastric disease in a General Hospital from July 1999 to August 2000 in Seoul. Data analysis was done with SAS 6.12 for descriptive statistics and PC-LISREL 8.13 Program for Covariance structural analysis. The results are as follows : 1. The fit of the hypothetical model to the data was moderate, thus it was modified by excluding 1 path and including free parameters and 2 path to it. The modified model with path showed a good fitness to the empirical data ($\chi$2=934.87, p<.0001, GFI=0.88, AGFI=0.83, NNFI=0.86, RMSR =0.02, RMSEA=0.07). 2. The perceived barrier, health promoting behavior, self-efficacy, and self-esteem were found to have significant direct effects on the quality of life. 3. The health concept, health perception, emotional state, and social support were found to have indirect effects on quality of life of chronic gastric disease. In conclusion, the derived model in this study is considered appropriate in explaining and predicting quality of life of chronic gastric disease. Therefore it can effectively be used as a reference model for further studies and suggested direction in nursing practice.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1149-1156
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• 2008

The conformational study on neutral and zwitterionic L-alanines (N-Ala and Z-Ala, respectively) and the transition state (TS) for their interconversion is carried out using ab initio HF and density functional B3LYP methods with the self-consistent reaction field method in the gas phase and in solution. At both the HF and B3LYP levels of theory, the local minimum N1 for N-Ala is found to be most preferred in the gas phase and a weak asymmetric bifurcated hydrogen bond between the amino hydrogens and the carbonyl oxygen appears to play a role in stabilizing this conformation. The local minima N2a and N2b are found to be the second preferred conformations, which seem to be stabilized by a hydrogen bond between the amino nitrogen and the carboxylic hydrogen. The relative stability of the local minimum N2b is remarkably increased in solution than that in the gas phase. The local minimum N2b becomes more stable than the local minimum N2a in most of the solution. On the whole the relative free energies of Z-Ala and TS become more lowered, as the solvent polarity increases. N-Ala prevails over Z-Ala in aprotic solutions but Z-Ala is dominantly populated in ethanol and water. In aprotic solutions, the population of Z-Ala increases somewhat with the increase of solvent polarity. The barrier to Z-Ala-to-N-Ala interconversion increases on the whole with the increase of solvent polarity, which is caused by the increase of stability for Z-Ala.

• 마이크로전자및패키징학회지
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• 제9권2호
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• pp.1-9
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• 2002

실제 BGA패키지에서 Sn-Ag-(Cu) 솔더와 금속패드가 반응하여 생성된 금속간 화합물의 특성을 Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS)f) X-ray Diffractometer (XRD)를 사용하여 분석하였다. EDS로 분석한 결과를 보면 BGA 패키지에서 Sn-Ag-Cu 솔더와 Au/Ni/Cu 금속층간의 반응으로 생성된 금속간화합물은 $(Cu,Ni)_6Sn_5$로 예상되며 . Cu의 편석은 솔더와 Ni 층 사이에서 발견되었다. XRD 분석결과 Cu를 함유하고 있는 Sn-Ag-Cu 솔더와 Ni층 사이에서는 $\eta -Cu_6 Sn_5$ 타입의 금속간화합물이 분석되었으며 Sn-Ag 솔더와 Ni층 사이에서는 $Ni_3$Sn_4$가 분석되었다. 계면에 생성된 금속간화합물은 리플로 회수와솔더내의 Cu의 함량에 따라증가하였다