http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Phenoxyethanol을 이용한 저자극 방부시스템 개발에 관한 연구
안기웅 ( Gi Woong Ahn ),이춘몽 ( Chun Mong Lee ),김형배 ( Heong Bae Kim ),정지헌 ( Ji Hean Jeong ),조병기 ( Byoung Kee Jo ) 대한화장품학회 2005 대한화장품학회지 Vol.31 No.1
최근, 민감성 피부가 증가함에 따라 화장품의 안전성이 매우 중요시되고 있으며, 특히 방부제는 화장품 사용에 따른 부작용을 일으킬 수 있는 주요 자극원의 하나로 알려져 있다. 하지만, 방부제의 세포 독성 피부 투과, 유/수 분배, 항균력 비교 및 이를 통한 피부 자극과의 상관성 분석에 관한 연구는 전무한 실정이다. 본 연구의 목적은 상기의 여러 factor를 고려하여 화장품에서 빈번히 사용되고 있는 방부제의 하나인 phenoxyethanol을 이용한 저자극 방부시스템 개발에 관한 것이다. MTT assay를 통하여 human norm기 fibroblast cell에 대한 독성을 평가해 본 결과, 세포 독성은 propylparaben > butylparaben > ethylparaben > methylparaben > triciosan > phenoxyethanol 순으로 확인되어 phenoxyethanol이 다른 방부제에 비해 낮은 세포 독성을 나타낸 반면, 피부 일차자극을 알아보기 위하여 수행한 인체 첩포시험에서는 triclosan, methylparaben에 비해 높은 피부 자극을 나타내었다. 5~8 주령의 웅성 무모생쥐의 피부를 적출하여 in vitro Franz diffusion cell system을 이용한 방부제의 피부 투과도를 측정하여 본 결과, 피부 투과도는 phenoxyethanol > methylparaben > ethylparaben > propylparaben > butylparaben > triclosan 순으로 확인되어 세포 독성이 낮은 phenoxyethanol의 높은 피부 자극이 높은 피부 투과도와 연관성이 큰 것을 확인하였다. 따라서, 본 연구에서는 비교적 독성이 낮은 phenoxyethanol의 피부 투과도를 감소시킬 수 있는 방법을 찾고자 하였으며, 연구 결과, 제형내 polarity가 낮은 oil을 사용할 경우 phenoxyethanol의 피부 투과가 현격히 감소하며, 피부 자극도 감소함을 알 수 있었다. Oil polarity에 따른 Phenoxyethanol의 유/수 분배 측정 결과, Polarity가 낮은 oil에서는 70% 이상의 Phenoxyethanol이 수상에 존재한 반면, polarity가 높은 oil에서는 약 70~90%의 phenoxyethanol이 유상에 존재하였다. 또한, 미생물에 대한 항균력도 phenoxyethanol이 수상에 많이 존재할수록 증가하는 경향을 나타내었다. 따라서, 제형 내 oil tomposition을 변화시킴으로써 phenoxyethanol의 사용량을 줄일 수 있을 뿐만 아니라, 피부 투과를 감소시켜 보다 피부 자극이 적은 저자극 방부시스템 개발이 가능하리라 보여 진다. Recently, according as people who have sensitive skin increase, we've been giving more importance to the safety of cosmetics. Especially, preservative is known to be one of the main stimuli which cause side-effects of cosmetics. However, there have been few reports describing cell cytotoxicity, skin penetration, oil-aqueous phase partition, anti-microbial activity of preservatives and their correlation with skin irritation. The study is aimed to develop low irritable preservative system with phenoxyethanol, one of the most commonly used preservatives in cosmetics, considering various factors mentioned above. According to our results of cell cytotoxicity against human normal fibroblasts by means of MTT assay, phenoxyethanol showed the lowest cytotoxicity when compared to other preservatives tested (cytotoxicity: pro-pylparaben > butylparaben > ethylparaben > methylparaben > triclosan > phenoxyethanol), but human patch test for assessing shin primary irritation revealed that phenoxyethanol has higher skin irritation than methylparaben and triclosan. We performed in vitro skin penetration test using horizontal Franz diffusion cells with skin membrane prepared from hairless mouse (5~8 weeks, male) to evaluate the rate of skin penetration of preservatives. From the results, we found that the higher irritable property of phenoxyethanol in human skin correlates with its predominant permeability (skin penetration: phenoxyethanol > methylparaben > ethylparaben > propylparaben > butylfaraben > triclosan). Therefore, we made an effort to reduce skin permeability of phenoxyethanol and found that not only the rate of skin penetration of phenoxyethanol but also its skin irritation is dramatically reduced in formulas containing oils with low polarity. In the experiments to investigate the effect of oil polarity on the oil-aqueous phase partition of phenoxyethanol, more than 70% of phenoxyethanol was partitioned in aqueous phase in formulas containing oils with low polarity, while about 70~90% of phenoxyethanol was partitioned in oil phase in formulas containing oils with high polarity. Also, in aqueous phase phenoxyethanol showed greater anti-microbial activity. Conclusively, it appears that we can develop less toxic preservative system with reduced use dosage of phenox-yethanol and its skin penetration by changing oil composition in formulas.
In vivo tracking of human mesenchymal stem cells in experimental stroke.
Kim, Daehong,Chun, Byoung-Gi,Kim, Yeon-Kyung,Lee, Yong Hyun,Park, Cheong-Soo,Jeon, Iksoo,Cheong, Chaejoon,Hwang, Tae-Sun,Chung, Hyungmin,Gwag, Byoung Joo,Hong, Kwan Soo,Song, Jihwan Pergamon Press ; Elsevier Science Ltd ; Elsevier S 2007 CELL TRANSPLANTATION Vol.16 No.10
<P>To understand the fates of human mesenchymal stem cells (hMSCs) following transplantation into a rodent model of middle cerebral artery occlusion (MCAo), magnetic resonance imaging (MRI) techniques were employed, hMSCs were labeled with ferumoxides (Feridex)--protamine sulfate complexes, which were visualized and examined by MRI up to 10 weeks following transplantation. Migration of the transplanted cells to the infarcted area was further confirmed by histological methods. We found that the hMSCs transplanted in MCAo models possess the capacity to migrate to the infarcted area extensively in both ipsilateral and contralateral injections, exhibiting a pathotropism. We also analyzed the detailed migration patterns of transplanted hMSCs. We speculate that the extensive migratory ability of hMSCs may represent a therapeutic potential for developing efficient cell transplantation strategies in stroke.</P>
이용범(Young-Bum Lee),이기천(Gi-Chun Lee),최병오(Byoung-Oh, Choi) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
Wind turbine, which is attracting part of the renewable energy and is researching continuously, is going to be large size for high efficiency. There is a pitch system to control the blade position to match with angle of the blade to make good efficiency in the wind turbine system. The wind turbine is focusing on the reliability improvement because working environment effect is bigger than any other points and specially, the reliability improvement of the pitch gear box is required by the customer because it is the key component of the wind turbine. Because of this, the establishment of criteria for pitch gearbox is required to make the methods of assessment because pitch gearbox is the part of the wind turbine closely related with ensuring the reliability. So, this study did the failure analysis of the pitch gearbox system, which is consisted with 6 or 9 sets of pitch gearboxes through researching and analyzing the site conditions. Also this study designed the life test method based on the failure analysis and working condition of the pitch gearbox. To design the accelerated life test of the pitch gearbox, this study have been considered the torque, lubrication condition, and frequency of use and etc. Finally, this selected the torque as the acceleration factor which is affected mainly to the system and also, the test equipment was developed based on the requirements of the life and performance test.