This study examined a timed cloze test for evaluating English proficiency in second language (L2) experimental research. Forty-five Korean college students were randomly assigned to either a timed or untimed condition. In the timed condition, the participants read the sentences of the text one phrase at a time, using the self-paced, cumulative, moving-window reading paradigm, and their reading time (RT) and accuracy were measured. In an untimed condition, the participants carried out a typical pencil-and-paper cloze test. Linear mixed-effect models were used to analyze the data. Although the accuracy data did not indicate any significant results, the RT data showed that the participants responded faster when they selected accurate answers and they answered function words rather than content words; also, as the participants’ TOEIC scores increased, a marginally significant RT difference was observed. A significant correlation was also found between the cloze test and high TOEIC scores in the timed condition. The results showed that the timed cloze test used in the study can provide useful data for L2 experimental research in measuring L2 proficiency.

Neuronal differentiation is a complex biological process accompanying cytoskeletal reorganization, including neurite outgrowth and growth cone formation. Therefore, neuronal differentiation is critically regulated by actin-related signaling proteins, such as small Rho GTPases, guanine nucleotide exchange factors (GEFs), and myosins. This study will demonstrate the change in activity of three small Rho GTPases, Rac, Cdc42, and Rho A, by treatment with blebbistatin (BBS), a specific inhibitor for myosin, during bFGF-induced neurite outgrowth in PC12 cells. Treatment with BBS induced morphological changes in growth cones and neurites during differentiation. A marked increase in protrusion and filopodia structures in growth cones, the shaft of neuritis, and cell membranes was observed in the cells treated with BBS. Activity of Rho GTPases showed the alterations in response to BBS. Activities of both Rac and Rho A were inhibited by BBS in a time-dependent manner. By contrast, Cdc42 activity was not changed by BBS. These results suggest that inactivation of myosin II by BBS induced morphological changes in neurites and growth cones and distinct regulation of three Rho GTPases during differentiation of PC12 cells.

본 연구는 새로운 항산화 및 미백 기능성 화장품 성분을 개발하기 위해 기존의 항산화와 미백 기능성 성분으로 알려진 두 가지 성분을 혼합한 새로운 조성을 개발하고, 이를 이용해 항산화 및 미백효과를 알아보고자 하였다. 두 가지 성분은 항산화와 멜라닌 생성억제 기능이 알려진 sulforaphane과 멜라닌 생성 억제 효과가 알려진 PF-3758309이다. 각 성분 및 혼합 조성에 대한 세포독성을 조사하여 세포독성이 나타나지 않는 농도를 결정하였다. 단독 처리 시 sulforaphane는 10 μ M까지, PF-3758309는 100 nM까지 세포독성이 없다는 것을 확인하였다. 두 화합물 10 μ M sulforaphane과 1 nM PF-3758309를 병합 처리 시 세포독성은 없었다. LPS 자극에 의해 생성된 일산화질소는 sulforaphane과 PF-3758309의 병합 처리시 현저히 감소되었다. α-MSH 에 의한 멜라닌 생성 역시 병합 처리에 의해 억제되었다. 화장품 소재로 사용 가능성을 확인하기 위해 혼합 조성 시료에 대한 인체적용시험을 실시하였다. 혼합조성 시료는 피부첩포에 의한 안전성 평가는 무자극으로 판정되었고, 피부밝기 증가효과와 피부 멜라닌 침착을 억제함을 확인하였다. 이러한 결과들로 혼합 조성물이 항산화와 미백 기능이 있는 새로운 기능성 화장품 조성으로 개발될 가능성을 확인할 수 있었다.