• Journal of The Korean Association For Science Education
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• v.38 no.2
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• pp.135-145
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• 2018

In this study, we investigated the argumentations of group and classroom discussions in socioscientific issues (SSI) discussion classes. Twenty-seven high school students participated in the SSI discussion classes on nuclear power generation. We observed and recorded the classes and also conducted semi-structured interviews. For the analyses, we revised a previous framework that was developed to analyze dialogic argumentations in the context of SSI. The analyses of the results indicated that there were more discourse schemes in the classroom discussions than the group discussions which are related to awareness and openness to multiple perspectives, evidence based reasoning, and on-going inquiry and skepticism. And there were few discourse schemes related to moral and ethical sensitivity in the group and classroom discussions. Various grounds, data, and information were presented in the classroom discussions. Students concentrated on carrying their claims and were not able to sympathize with and accept other opinions. Therefore, there were few discourse schemes to reach consensus. In addition, they perceived classroom discussions as competitive and actively rebutted other claims or grounds. The levels of argumentation were also high in the classroom discussions. The group discussions were held in relaxed atmosphere, and they asked the opponents more for clarification or additional information and evidences. However, classroom discussions were held in serious atmosphere, and they actively queried the validity of the claims or grounds. Based on the results, some suggestions to implement SSI discussion classes were discussed.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.37-41
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• 2012

The current standard for testing tetrodotoxin (TTX) in foodstuffs is the mouse bioassay (MBA) in Korea as in many other countries. However, this test suffers from potential ethical concerns over the use of live animals. In addition, the mouse bioassay does not test for a specific toxin thus a sample resulting in mouse incapacitation would need further confirmatory testing to determine the exact source toxin (e.g., TTX, STX, brevotoxin, etc.). Furthermore, though the time of death is proportional to toxicity in this assay, the dynamic range for this proportional relationship is small thus many samples must be diluted and new mice be injected to yield a result that falls within the quantitative dynamic range. Therefore, in recent years, there have been many efforts in this field to develop alternative assays. High performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) has been emerged as one of the most promising options. A LC-MS-MS method involves solid-phase extraction (SPE) and followed by analysis using an electrospray in the positive ionization mode and multiple reactions monitoring (MRM). To adopt LC-MS-MS method as alternative standard for testing TTX, we performed a validation study for the quantification of TTX in puffer fish. This LC-MS-MS method showed good sensitivity as limits of detection (LOD) of $0.03{\sim}0.08{\mu}g/g$ and limits of quantification (LOQ) of $0.10{\sim}0.25{\mu}g/g$. The linearity ($r^2$) of tetrodotoxin were 0.9986~0.9997, the recovery were 80.9~103.0% and the relative standard deviations (RSD) were 4.3~13.0%. The correlation coefficient between the mouse bioassay and LC/MS/MS method was higher than 0.95.

• Korean Journal of Radiology
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• v.22 no.6
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• pp.959-969
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• 2021

Objective: This study aimed to evaluate the role of preoperative two-dimensional (2D) shear wave elastography (SWE) in assessing the stages of liver fibrosis in patients with suspected biliary atresia (BA) and compared its diagnostic performance with those of serum fibrosis biomarkers. Materials and Methods: This study was approved by the ethical committee, and written informed parental consent was obtained. Two hundred and sixteen patients were prospectively enrolled between January 2012 and October 2018. The 2D SWE measurements of 69 patients have been previously reported. 2D SWE measurements, serum fibrosis biomarkers, including fibrotic markers and biochemical test results, and liver histology parameters were obtained. 2D SWE values, serum biomarkers including, aspartate aminotransferase to platelet ratio index (APRi), and other serum fibrotic markers were correlated with the stages of liver fibrosis by METAVIR. Receiver operating characteristic (ROC) curves and area under the ROC (AUROC) curve analyses were used. Results: The correlation coefficient of 2D SWE value in correlation with the stages of liver fibrosis was 0.789 (p < 0.001). The cut-off values of 2D SWE were calculated as 9.1 kPa for F1, 11.6 kPa for F2, 13.0 kPa for F3, and 15.7 kPa for F4. The AUROCs of 2D SWE in the determination of the stages of liver fibrosis ranged from 0.869 to 0.941. The sensitivity and negative predictive value of 2D SWE in the diagnosis of ≥ F3 was 93.4% and 96.0%, respectively. The diagnostic performance of 2D SWE was superior to that of APRi and other serum fibrotic markers in predicting severe fibrosis and cirrhosis (all p < 0.005) and other serum biomarkers. Multivariate analysis showed that the 2D SWE value was the only statistically significant parameter for predicting liver fibrosis. Conclusion: 2D SWE is a more effective non-invasive tool for predicting the stage of liver fibrosis in patients with suspected BA, compared with serum fibrosis biomarkers.