• Archives of Pharmacal Research
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• v.21 no.2
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• pp.128-134
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• 1998

Nitric oxide synthase, NOS (EC.1.14.13.39), was purified from bovine pancreas over 5,500-fold with a 7.6% yield using 30% ammonium sulfate precipitation, and $2^1$,$5^1$-ADP-agarose and calmodulin-agarose affinity chromatography. The purified bovine pancreatic NOS (bpNOS) showed a single band on SDS-PAGE corresponding to an apparent molecular mass of 160 kDa, whereas it was 320 kDa on non-denaturating gel-filtration. This indicated a homodimeric nature of the enzyme. The specific activity of the purified bpNOS was 31.67 nmol L-citrulline fored/mtn/mg protein and an apparent $K\textrm{m}$ for L-arginine was 15.72 $\mu\textrm{M}$, The enzyme activity was dependent on $Ca^{2+}$ and calmodulin, and to a lesser extent on NADPH, FAD and FMN. $H_4B$ was not required as a cofactor for the activity. In an inhibition experiment with L-arginine analogues, $N^G$-nitro-L-arginine (NNA) had the most potent inhibitory effect on bpNOS, and $N^{G}$, $N^{G1}$-dimethyl-L-arginine (symmetric; sDMA) did not have any inhibitory effect. Immunohistochemical analysis of the bovine pancreas using brain type NOS antibody (anti-bNOS antibody) revealed that acinar cells showed strong immunoreactivity against the antibody.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.459-468
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• 2014

Educational Discourses on the nature of science(NOS) identify understanding of the role of scientific knowledge, especially the distinction between law and theory, as a crucial goal of instruction. However, the scientist community uses the terms such as law, theory, and principle without explicit definition so that the terms have no coherent meanings in their conventional language expression. The inconsistency between the norm and the reality could impose confusion on the teaching and learning. From the awareness of the problem, this study critically reviews the science education research papers and literatures on the philosophy of science which focus on the meaning of law, theory, or principle and the structure of scientific knowledge. From the examination of the science education researches, it is revealed that the disparity between the normative meanings of the law and theory by NOS researchers and actual usage of the terms is quite serious. From the review of the literatures of the philosophy of science, the necessity of the distintion of three categories: law, theory, and principle beyond the dichotomy between law and theory is brought up. By synthesizing the related literatures, we provide an outline of the characteristics of knowledges belonging to law, theory, and principle. Considering the conflict between the normative definition and the conventional language, it could be unnecessary to emphasize clear distinction on the terms as an instructional goal. Instead, the goal of instruction should focus on that there are three types of scientific knowledges of different functions and characteristics.

• Journal of The Korean Association For Science Education
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• v.29 no.2
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• pp.221-239
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• 2009

The purpose of this study was to explore how 9th grade students' understanding of the nature of science developed during a one-year implementation of NOS learning materials. The lessons were a combination of short readings in episodes in the history of science with accompaning response booklets consisting of illustrations and questions. The lessons were designed to be 45 minutes in length and were implemented over ten months of the school term. Data on students' understanding as it developed during the implementation were obtained from test items, questionnaires, and students' journal. Findings indicate that students showed changes in their understanding of the nature of science towards modern views of the nature of science. However, they showed understanding of tentativeness of scientific knowledge, they also showed belief of absoluteness of scientific knowledge.

• Biomolecules & Therapeutics
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• v.21 no.1
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• pp.21-28
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• 2013

Microglia play a role in maintaining and resolving brain tissue homeostasis. In pathological conditions, microglia release pro-inflammatory cytokines and cytotoxic factors, which aggravate the progression of neurodegenerative diseases. Autophagy pathway might be involved in the production of pro-inflammatory cytokines and cytotoxic factors in microglia, though details of the mechanism remain largely unknown. In the present study, we examined the role of the autophagy pathway in activated BV2 microglia cells. In BV2 cells, rapamycin treatment activated the formation of anti-LC3-labeled autophagosomes, whereas the ATG5 depletion using siRNA-ATG5 prevented the formation of LC3-labeled autophagosomes, indicating that BV2 cells exhibit an active classical autophagy system. When treated with LPS, BV2 cells expressed an increase of anti-LC3-labeled dots. The levels of LC3-labeled dots were not suppressed, instead tended to be enhanced, by the inhibition of the autophagy pathway with siRNA-ATG5 or wortmannin, suggesting that LPS-induced LC3-labeled dots in nature were distinct from the typical autophagosomes. The levels of LPS-induced expression of iNOS and IL6 were suppressed by treatment with rapamycin, and conversely, their expressions were enhanced by siRNA-ATG5 treatment. Moreover, the activation of the autophagy pathway using rapamycin inhibited cell death of LPS-stimulated microglia. These results suggest that although microglia possess a typical autophagy pathway, the glial cells express a non-typical autophagy pathway in response to LPS, and the activation of the autophagy pathway suppresses the expression of iNOS and IL6, and the cell death of LPS-stimulated microglia.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.1
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• pp.30-42
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• 2023

The purpose of this study is to quantitatively and qualitatively analyze the science journals written by pre-service elementary school teachers, and to categorize the view on the nature of science and the process of their change. For this purpose, 112 science journals written by 13 pre-service elementary school teachers were analyzed. The frequency of each area was analyzed using the research framework of the four areas of the nature of science, and the pattern of change in perspective on the nature of science was inductively derived and classified using the VNOS-C test analysis framework. As a result, The nature of scientific thinking, nature of scientific knowledge, nature of STS, and nature of scientific inquiry were described in relatively similar proportions, but among them, The nature of scientific thinking appeared in the largest percentage, and the nature of scientific inquiry was described in the smallest percentage. The variability of scientific knowledge, the importance of empirical evidence, and the positive and negative effects of science were especially intensively addressed. In addition, the changing aspects of pre-service elementary school teachers' perspectives on the nature of science could be categorized into 'naive view maintenance type', 'informed view maintenance type', 'regression type', 'development type', and 'mixed type'. The element of 'the empirical nature of scientific knowledge' showed various patterns of change depending on the students, and most of the students maintained a informed view on the tentativeness of scientific knowledge for several sessions.

• Journal of The Korean Association For Science Education
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• v.34 no.7
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• pp.677-691
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• 2014

Understanding of the nature of science (NOS) has been a consistent topic as one of the most important goals in science education for the past several decades. Even though there is a variety of research related with the NOS conducted in science education, few researches has been conducted for the conception of scientists regards to the nature of science (Bayir et al., 2014; Taylor et al., 2008; Wong & Hudson, 2008). Recently, researchers in science education turned their attention to identifying views of scientists about the nature of science since they recognized the importance of participation of scientists in science education (Southerland et al., 2003; Taylor et al., 2008). This study was conducted to examine the Korean scientists' views of the nature of science. Through the use of semi-structured questionnaire and in-depth interview the views of 35 scientists who belong to the Korean-American Scientists and Engineers Association (KSEA) regards to the nature of science were explored. Findings show that while the scientists have more informed views with respect to the tentativeness of scientific knowledge, cultural and social influence embedded in science, the limitation of science, and the collaboration of science with others, the scientists have more na${\ddot{i}}$ve views about the distinction between laws and theories, the existence of a universal scientific method, and the importance of imagination and creativity. As such, it can be assumed that the scientists cannot conceptualize their notion in a philosophical sense even though they are engaged in scientific work in reality (Bayir et al., 2014).

• Journal of the Korean Chemical Society
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• v.65 no.5
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• pp.333-346
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• 2021

In this study, we developed education materials using history of science related to the experiment of 'Boyle's air pump' and the Boyle and Hobbs' debate of vacuum to find out the perceptions of NOS by pre-service chemistry teachers. For the study, 29 pre-service chemistry teachers at a college of education in Chungcheongbuk-do were selected. As RFN items that were related to the contextual situation developed in this study, items in the categories of 'Aims and Values', 'Scientific practices', 'Scientific Methods among Educational Applications' and 'Social-Institutional Aspects among Educational Applications' were selected. Through the items of RFN, the perceptions of pre-service teachers in non-contextual situations were investigated. Then we presented the pre-service teachers with the situation related to Boyle's experiment on air pump and Boyle and Hobbes' debate over vacuum. In addition, their perception of NOS was examined in contextual situations related to RFN items. Responses to the items, experimental results related to Boyle's Law, group discussion, and interview data were collected as data. As a result of the study, it was found that pre-service teachers had informed perceptions in most of the items, but cases with naive views or mixed views were found in context experimental situations. This study can contribute to the NOS education for pre-service chemistry teachers by development of context situation education materials related to NOS and by finding out their perceptions in the non-contextual and contextual situation.

• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.823-840
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• 2012

The importance of teaching the nature of science (NOS) has been emphasized in the science curriculum, especially in the science curriculum for science-gifted students. Nevertheless, few studies concerning the structure and formation of students' mental model on NOS have been carried out. This study aimed to explore science-gifted students' understanding of 'fact', 'hypothesis', 'theory', 'law', and 'scientificness' by utilizing semantic network analysis. One hundred ten science-gifted middle school students who were selected by a national university participated in this study. We collected students' written responses of five items and analyzed them by the semantic network analysis(SNA) method. As a result, the core ideas of students' understanding of 'fact' were proof and reality, of 'hypothesis' were tentativeness and uncertainty, of 'theory' was proven hypothesis by experimentation, of 'law' were absoluteness and authority, and of 'scientificness' were factual evidence, verifiability, accurate and logical theoretical framework. The result of integrated semantic network illustrated that the viewpoint of science-gifted students were similar to absolutism and logical positivism (empiricism). Methodologically, this study showed that the semantic network analysis method was an useful tool for visualization of students' mental model of scientific conceptions including NOS.

• Journal of The Korean Association For Science Education
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• v.33 no.3
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• pp.581-596
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• 2013

The aim of this study was to identify students' views on the orientation of science and to investigate the relationship between their views and decision-making on socio-scientific issues (SSI). In this study, 27 university students attending a science course were asked to discuss four controversial issues: the Toyota recall, the green car, the global warming and swine influenza (influenza A (H1N1)). The study was comprised of two stages. At the first stage, we examined students' views on the nature of science and on the orientation of science with the open-ended questionnaire based on VNOS and VOSTS. While they held relatively similar views on the nature of science, their views on the orientation of science were distinct as pragmatic, intrinsic, communal and ethical views. At the second stage, to examine the role of their views on the orientation of science in decision-making, we selected four students who had similar views on NOS but different views on the orientation of science. The four students were selected from each group of views on the orientation of science and their decision-making processes were analyzed following grounded theory. Across SSIs, they relied upon their views on the orientation of science as the strategies for decision, though considered different perception, and causal and contextual conditions. This study indicates that understanding students' views on the orientation of science would be helpful for achieving scientific literacy for informed decision.

• Journal of The Korean Association For Science Education
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• v.38 no.1
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• pp.27-42
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• 2018

This study aims to suggest the conceptual framework for the Nature of Technology (NOT) by examining the current researches regarding the NOT in science and technology education and to analyze the conceptions of experts in science, technology, and engineering fields based on the framework of NOT. The NOT conceptual framework developed in the study consisted of the six domains of NOT, which are 1. Technology as artifacts, 2. Technology as knowledge, 3. Technology as practice, 4. Technology as system, 5. The role of technology in society, and 6. History of technology. Also, the results of analyzing the conceptions for the 30 experts in science, technology, and engineering fields emphasize on the three domains of the 3. Technology as practice, 4. Technology as system, and 5. The role of technology in society among the 6 domains of the framework of the six domains of the NOT framework. This findings are different from the results of previous researches conducted in science and technology education for exploring the conceptions of NOT in the POV of the public and students. As such, the results show that while the public and students possess naive ideas on NOT only focusing on the technology as products and tools, experts in science, technology, and engineering fields possess the authentic views of the NOT reflecting the complex and abstract concepts of technology in terms of the perspectives of philosophy of technology.