Fetal Bovine Serum (FBS) plays a crucial role in animal cell culture; however, the increasing number of bovine fetuses used and sacrificed solely for FBS collection has raised ethical concerns globally. The welfare of fetuses during FBS blood collection has become a key focus of debate among animal welfare and ethics organizations worldwide. Previous studies indicate that heat-inactivated coelomic fluid (HI-CF) from the earthworm Perionyx excavatus may serve as a viable FBS alternative in adherent cell cultures. This study evaluates the potential of HI-CF as an FBS substitute during the in vitro maturation (IVM) stage of bovine embryo culture, with a focus on improving developmental rate through antioxidation effects. In this study, 2% HI-CF was incorporated into IVM media, assessing its impact on cell growth, differentiation, and the expression of genes related to antioxidation. The group of 2% of HI-CF exhibited a trend toward increased cleavage and blastocyst development rates compared to the control group. Although antioxidant genes such as NRF2 and GSR showed no statistically significant differences between the control and treatment groups, a trend toward increased expression was observed. Conversely, GPX1 displayed a trend of decreased expression. Notably, IGF1 and NQO1 were significant upregulated (p < 0.05) in the 2% HI-CF group. Additionally, oocytes stained with H2DCFDA showed a significantly reduced ROS levels (p < 0.05) in the 2% HI-CF group compared with controls. These findings suggest that HI-CF's antioxidative effects support enhanced cell growth and blastocyst development rate, surpassing those observed with FBS. Consequently, HI-CF shows promise as an effective alternative to FBS in vitro maturation of bovine oocytes.

The Kori Unit 1 and Wolsong Units 1, commercial reactors in South Korea, were permanently shut down due to the expiration of their design lifetime. Therefore, nuclear power plants that have been permanently shut down must be dismantled, and the site must be finally released after removing the remaining radionuclides. Domestic regulatory standards for site remediation should not exceed 0.1 mSv per year based on effective dose. In addition, it is necessary to calculate the preliminary Derived Concentration Guideline Levels (DCGL) to prove that the conditions are met. Therefore, in this study, the input factor considering the geological characteristics of the site of Kori Unit 1 was investigated, and the preliminary Derived Concentration Guideline Levels were calculated and compared with the results of previous studies. As a result of comparative analysis, 60Co, 134Cs, and 137Cs, which are gamma-ray emitting radionuclides, had similar values to DCGL of previous studies A and B. However, 63Ni, a beta-rayemitting nuclide, was 5.94×104 Bq·g−1 in this study and 8.47×101 Bq·g−1in previous study B, resulting in a difference of about 700 times. In addition, in the case of 90Sr, this study and previous study A were derived similarly, but this study was 5.34×101 Bq·g−1 and previous study B was 1.18×10−1 Bq·g−1, resulting in a difference of about 450 times. This difference is judged to be because, unlike this study using only the industrial worker scenario, in the case of previous study B, the resident farmer scenario was mixed and used, which considers the internal exposure caused by ingestion of food produced in the contaminated area. In this study, it was confirmed that DCGL according to the change of geological factors of the site did not have a significant effect on gamma-ray-emitting nuclides. However, it was confirmed that considering the intake of food affects the DCGL of beta-ray-emitting nuclides. Therefore, there is a need to conduct future studies applying intake input factors that meet domestic conditions.

The study investigated ten Korean secondary English teachers’ views on to what extent core competencies were reflected in textbooks using 18 Likert-type statements. This study also examined their views on how well cultural contents and activities met curricular objectives of teaching culture through open-ended questions and interviews. Results showed that the three items on civic competence had lower means except for the one on ethical use of information collected in class. Teachers replied that tasks for each grade were deficient in helping students feel proud of their own culture and developing positive attitudes toward other cultures. They thought that current cultural contents lacked diversity despite positive improvements in including other cultures over the years and possibility of meeting curricular goals. Consequently, they made various efforts to offer appropriate culture teaching using additional materials and/or activities with diverse teaching strategies and techniques. Some implications are drawn from these results for better culture teaching.