Advances in Internet technology have made possible, rapid adoption of e-learning in many fields of society. Various educational methods for e-learning have been developed because personalization can ...be easily implemented through web services. However, these e-learning methods are not widely used because it is difficult for instructors to apply them in developing their courseware. Currently, the most widely used style of e-learning courseware is viewing video clips of lectures and discussing the lecture using bulletin boards. It is an electronic version of the traditional classroom. In this paper, we propose a user-friendly e-learning framework that supports personalization and collaboration between the instructor and the students. Instructors can create various levels of learning objects and define the relationships between the objects. Students can select the topics of their interest and dynamically adjust the level of learning in real time. Multiple instructors can cooperate in expanding the courseware. All the participants can also annotate the learning materials independently.
본 연구에서는 동해안에서 채집된 88종의 해조류에 대하여 미백제로서 응용 가능성을 알아보기 위해 멜라닌 생성에 미치는 영향을 in vitro 실험을 통해 알아보았다. Melan-a 세포에 해조류 추출물을 처리하여 멜라닌 양을 측정한 결과, 고리매, 미역쇠, 왜모자반, 감태, 톳추출물에서 멜라닌 생성이 감소되었으며, 특히 미역쇠추출물을 처리하였을 때 가장 ...유효하게 농도의존적으로 멜라닌 생성이 감소되었다. 멜라닌 생성 억제 효과가 tyrosinase 활성 저해와 관련 있는지를 확인한 결과, 약한 활성을 가지지만 직접 작용하여 활성을 저해하지는 않으면서, 세포 내의 tyrosinase 활성을 농도의존적으로 저해하였다. 이는 세포 내 tyrosinase 활성저해가 직접적이 아닌 다른 기전에 의해 일어난다는 것을 의미하며, 그 기전 중의 하나인 α-glucosidase활성을 측정한 결과 농도의존적으로 활성을 저해하였으며, 세포 내 tyrosinase 활성 저해와 높은 상관도를 보임을 확인하였다. 즉 미역쇠추출물은 N-linked glycoprotein인 tyrosinase의 glycosylation을 억제하여 tyrosinase의 세포 내 이동이나 활성을 억제할 수 있음을 알 수 있었다. 결론적으로, 미역쇠추출물은 피부 미백에 유효한 활성을 나타내는 천연 유용자원으로 활용할 가치가 있는 것으로 사료된다.
In this study, we investigated the effect of 88 marine algae extracts on melanin synthesis to develop new whitening agents. Among varieties of marine algae tested, the ethyl acetate extracts from Endarachne binghamiae (EB), Scytosiphon lomentaria, Sargassum yezoense, Ecklonia cava and Sargassum fusiforme inhibited melanin synthesis in melan-a cells. EB treatment showed the strongest inhibitory activity in melanin synthesis, compared with that of other extracts. EB-mediated inhibition of melanin synthesis appeared to be associated with inhibition of α-glucosidase-dependent glycosylation of tyrosinase in melan-a cells. In addition, EB treatment did not affect mushroom tyrosinase or cell-extracted tyrosinase activity in vitro. Taken together, our findings suggest that anti-browning effect of EB on skin is mediated through regulation of α-glucosidase activity and subsequent inhibition of tyrosinase activity and melanin synthesis, and further development of EB as a potential agent for skin whitening.
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