This study investigated two science teachers' practical knowledge shaped during their science classes which intend to realize social construction of scientific models. The teachers' practical knowledge was qualitatively examined in terms of five content categories defined by Elbaz through the reflection-in-action based on video data of their teaching as well as the reflection-on-action based on their narratives and interview data obtained after their classes. The results shows: 1) two science teachers implemented their practical knowledge on appropriate subject matter knowledge when they provided students with scaffoldings to support building scientific models during the classes.2) The teachers' knowledge about science curriculum played important roles to change the purposes of the classes from the transmission of difficult science concepts to the construction of scientific model appropriate to learning goals. 3) The teachers' implementation of pedagogical knowledge changed toward supporting students' group activities and model generations aligned to the intention of social construction of scientific models. 4) The teachers' practical knowledge about their 'selves' showed that a teacher's perception and implementation of his/her roles of helper, guide, or facilitator are important for students to construct scientific models through group activities. 5) The two teachers' practical knowledge the milieu of schooling is realized by their modes of interactions with student groups during their classes. Two teachers acted like a co-player with his students or like a coach to students near a playground. We discussed domain-specific characteristics about scientific model construction.
The applicability of the ultrasonic wave method to the extraction of useful components from seaweeds was investigated. Extracts from freeze-dried Ecklonia cava powder were prepared with hot water (65°C), water (24°C), 50% ethanol, and 100% ethanol, and ultrasonic extraction was also performed. The content of phenolic compounds and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and tyrosinase inhibitory activity of the extracts were analyzed, and differences in the data obtained by the ultrasonic extraction and the traditional extraction methods were compared. The phenolic content in the E. cava extract by ultrasonic extraction (142.80 mg/g) was approximately 14 times higher than the phenolic content in the hot water extract (10.03 mg/g). The DPPH radical scavenging and the tyrosinase inhibitory activities of the ultrasonic extract were approximately 4 times and 14 times higher than the hot water extracts, respectively. The correlation between the phenolic content and the DPPH radical scavenging activity (R2=99.47) and between the phenolic content and the tyrosinase inhibitory activity (R2=99.99) was very high. These results indicate that ultrasonic extraction is more suitable than traditional extraction for the extraction of useful components from E. cava.
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