• Journal of The Korean Association For Science Education
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• v.40 no.4
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• pp.399-413
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• 2020

In this study, we analyzed science teachers' NOS-PCK in Science Inquiry Experiment lessons. Four science teachers in charge of Science Inquiry Experiment in high schools located in the Seoul metropolitan area participated in the study. NOS Lessons were observed, all of the teaching-learning materials were collected, and semi-structured interviews were conducted. All the collected data were analyzed according to five factors of NOS-PCK. As a result of the study, their understanding and consideration of the curriculum related to NOS were insufficient in some cases. They thought that given inquiry activities or textbook composition was not effective for NOS teaching so that they actively reconstructed the curriculum. In terms of teaching strategies, their lessons were close to explicit approaches. However reflective approaches were generally lacking. They were neglected in evaluating NOS for reasons that views of NOS are individually subjective or that NOS is not an area of cognitive learning. They guessed the state of students by relying on their own experiences rather than based on evaluation results. They recognized a specific aspect of values of NOS learning. And intention to teach NOS played an important role throughout their classes. Based on the above results, we discuss some ways to improve the professionalism of science teachers for NOS teaching.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.721-738
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• 2018

Nature of Science(NOS) has been a well-organized focus of science education and one of the key elements in defining and cultivating scientific literacy for more than a century. In recent years, a specific description of NOS, which is often known as 'the consensus view of NOS', has become very influential and has gained ready acceptance as an arrangement for both curriculum building and research into understanding of NOS by students and teachers in many countries around the world. This study has two purposes; one is to review some debates and criticism on the consensus view of NOS which consists of a list of sentences to describe nature of refined and general science, which have been heated up for the last few years by many prominent science education researchers, and the other is to consider alternative perspectives on NOS for the purpose of a new direction of NOS education. As a result of an investigation into such views as 'Teaching about NOS', 'Critical NOS', 'Critical Thinking-NOS', 'Whole Science', 'Features of Science' and 'Reconceptualized Family Resemblance Approach to NOS', some implications which focus on the generality and plurality of content knowledge of NOS based on current philosophy of science and sociology of scientific knowledge are suggested for the improvement of teaching and learning NOS.

• Advances in nano research
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• v.12 no.5
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• pp.501-514
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• 2022

This study aimed to investigate the effects and potential mechanisms of Chikusetsusaponin V (CsV) on endothelial nitric oxide synthase (eNOS) and vascular endothelial cell functions. Different concentrations of CsV were added to animal models, bovine aorta endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs) cultured in vitro. qPCR, Western blotting (WB), and B ultrasound were performed to explore the effects of CsV on mouse endothelial cell functions, vascular stiffness and cellular eNOS mRNA, protein expression and NO release. Bioinformatics analysis, network pharmacology, molecular docking and protein mass spectrometry analysis were conducted to jointly predict the upstream transcription factors of eNOS. Furthermore, pulldown and ChIP and dual luciferase assays were employed for subsequent verification. At the presence or absence of CsV stimulation, either overexpression or knockdown of purine rich element binding protein A (PURA) was conducted, and PCR assay was employed to detect PURA and eNOS mRNA expressions, Western blot was used to detect PURA and eNOS protein expressions, cell NO release and serum NO levels. Tube formation experiment was conducted to detect the tube forming capability of HUVECs cells. The animal vasodilation function test detected the vasodilation functions. Ultrasonic detection was performed to determine the mouse aortic arch pulse wave velocity to identify aortic stiffness. CsV stimulus on bovine aortic cells revealed that CsV could upregulate eNOS protein levels in vascular endothelial cells in a concentration and time dependent manner. The expression levels of eNOS mRNA and phosphorylation sites Ser1177, Ser633 and Thr495 increased significantly after CsV stimulation. Meanwhile, CsV could also enhance the tube forming capability of HUVECs cells. Following the mice were gavaged using CsV, the eNOS protein level of mouse aortic endothelial cells was upregulated in a concentration- and time-dependent manner, and serum NO release and vasodilation ability were simultaneously elevated whereas arterial stiffness was alleviated. The pulldown, ChIP and dual luciferase assays demonstrated that PURA could bind to the eNOS promoter and facilitate the transcription of eNOS. Under the conditions of presence or absence of CsV stimulation, overexpression or knockdown of PURA indicated that the effect of CsV on vascular endothelial function and eNOS was weakened following PURA gene silence, whereas overexpression of PURA gene could enhance the effect of CsV upregulating eNOS expression. CsV could promote NO release from endothelial cells by upregulating the expression of PURA/eNOS pathway, improve endothelial cell functions, enhance vasodilation capability, and alleviate vessel stiffness. The present study plays a role in offering a theoretical basis for the development and application of CsV in vascular function improvement, and it also provides a more comprehensive understanding of the pharmacodynamics of CsV.

• Journal of The Korean Association For Science Education
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• v.36 no.1
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• pp.147-158
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• 2016

This study examined the changes of preservice biology teachers' NOS pedagogical content knowledge through two consecutive science methods courses: NOS understandings; attitudes toward teaching science; difficulties of NOS teaching; NOS teaching strategies; and views of orientation of NOS teaching. During the science methods course I, the preservice teachers engaged in discussions and reflections on what science is and how scientific knowledge has produced, drawing NOS aspects from episodes of history of science, and planning the lessons cooperating NOS instructional objectives. Then the next semester, through the science methods course II, the preservice teachers had a chance of the simulated teaching by adopting NOS teaching and learning activities in the context of the secondary biology context. The preservice teachers, further, reflected on their NOS teaching. The results showed that the preservice teachers constructed the NOS pedagogical content knowledge. They significantly improved their views of NOS and its teaching(p<.05) after the science methods course I, and retained their understanding after the science methods course II(p>.05). The preservice teachers mentioned the difficulties of teaching NOS in the secondary biology context, and further suggested effective NOS teaching methods in their reflective journals.

• Journal of The Korean Association For Science Education
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• v.28 no.2
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• pp.169-179
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• 2008

In this study, 46 teaching materials for understanding the nature of science (NOS) were developed based on the 42 statements describing the NOS. Each teaching material involves scientific knowledge and scientific inquiry skills as well as NOS statements. Teaching materials consist of students' learning worksheets and teachers' guides. Among the materials, 11 materials for understanding the nature of scientific thinking (NOST) were applied to 3 scientifically gifted students. As results, the degree of difficulty was appropriate and students showed interests in scientific thinking rather than new concepts or inquiry activities involved in the materials. It was expected that understating the NOST would be helpful for conducting scientific inquiry in more authentic way. And similarly to the Park's (2007) theoretical discussions about the relationship between the NOS and scientific creativity, students actually responded that undertrading the NOST could help their creativity. Therefore, it was expected that teaching the NOST would be plausible elements for teaching scientific creativity.

• Journal of The Korean Association For Science Education
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• v.28 no.1
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• pp.89-99
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• 2008

In this study, we investigated the effects of explicit and reflective instruction about nature of science (NOS) using episodes from the history of science upon students' understanding about NOS, achievement, and enjoyment of science lessons. Four classes of ninth graders (N=129) at a coed middle school were divided into the control and the treatment groups. The students were taught about the composition of material for 11 classes. Before the instruction, most of the students in both the control and the treatment groups held naive views about NOS. After the instructions, the views about NOS of the control group students did not change, whereas the students in the treatment group held more adequate views about NOS. The high-level students in the treatment group showed more adequate views about NOS than the low-level students. However, there were no significant differences between the test scores of the two groups in the achievement and the enjoyment of science lessons.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.344-351
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• 2005

Nitric oxide (NO) and calcium-binding proteins occur in various types of cells in the central nervous system. They are important signaling and calcium buffering molecules, respectively. In the present study, using immunocytochemistry we examined the distribution and the co-localization pattern of neurons containing neuronal nitric oxide synthase (nNOS) and parvalbumin in the visual cortex of hamster. The overall number of parvalbumin-immunoreactive (IR) neurons was 17 times higher than that of the nNOS-IR neurons in the hamster visual cortex. The highest differences were found in layer V, where parvalbumin-IR neurons were 54.7 times more abundant than nNOS-IR neurons. Many nNOS- and parvalbumin-IR neurons were similar in size, shape, and manner of distribution in the visual cortex. However, two-color immunofluorescence revealed that no neurons in the hamster visual cortex expressed both nNOS and parvalbumin. The present results indicate that there are subtle species differences in the co-localization pattern between nNOS and calcium-binding proteins. The present results also suggest not only the heterogeneity and functional diversity of nNOS-IRneurons in the visual cortex, but also the importance of understanding animal diversity

• Journal of Korean Elementary Science Education
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• v.41 no.4
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• pp.701-724
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• 2022

In this study, the Nature of Science (NOS) instrument for elementary school students in the form of open questionnaires was developed specifically to reveal elementary school students' perceptions of the NOS, and its validity and effectiveness were investigated. To develop a NOS instrument for elementary school students, problems that may occur when applying the existing NOS instruments to elementary school students were analyzed and based on this, the development direction of the NOS instrument was established. In addition, after selecting seven NOS types suitable for the level of elementary school students, the preliminary instrument was produced by modifying and supplementing the items in the existing instruments for each type or by developing new items. Finally, the NOS instrument consisting of eight questions was developed by adding one question asking for a comprehensive understanding of science to seven questions related to each type of NOS after a content validity test of the science education expert group. To verify the practical effect of the developed instrument, pre- and post-tests were conducted on 50 students in two classes of sixth grade at two elementary schools in Seoul: 'existing instrument → development instrument' in one class, and 'development instrument → existing instrument' in the other class. The collected data were then compared and evaluated through summary content analysis and analyzed by executing the Wilcoxon signed-rank test. As a result of comparing and analyzing students' responses to the existing NOS instrument and the developed NOS instrument, students' perspectives on the NOS were more diverse when using the developed instrument, and the level of error in the response caused by misinterpreting the intention of the question was reduced. In addition, when using the developed instrument, the responses of the majority of students at a statistically significant level changed more specifically. In this study, the implications for the development of NOS instruments suitable for elementary school students were discussed based on these results.

• Journal of Gifted/Talented Education
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• v.21 no.2
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• pp.391-405
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• 2011

The nature of science has been recognized in a great deal in the field of science education. However, only few innovative programs are offered for science-gifted students to improve their recognition of the nature of science. The current study describes and analyzes science-gifted students' understandings of the nature of science (NOS). In addition, the study looks into contradictory views among the aspects of NOS, which are fundamental data in constructing target programs on NOS for science gifted students. Data used in this study were collected from 73 middle school science-gifted students using an open-ended questionnaire, VNOS. The results of this study showed that the participants' understanding of NOS was significantly distributed on naive or transition view except for 'tentative NOS', and the results revealed inconsistent view among the aspects of NOS. This study proposes two suggestions to enhance the recognition of science-gifted on NOS of science to informed state and to have consistent perspectives with other areas. First, the role of experiment has to be changed-it should be the process in constructing scientific knowledge rather than an instrument to check scientific knowledge to transform perspective on experimental data and scientific knowledge. Second, various opportunities must be provided to science-gifted students, so they can experience the culture and community of scientists and science to gain a wider insight of science.

• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.77-86
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• 1995

To effectively modify tree function with genetic engineering, transgenes must be expressed at the proper level in the appropriate tissues at suitable developmental stages. Toward understanding the spatial and temporal expression of transgenes in woody plants, transgene expression was evaluated in three greenhouse-grown, transgenic lines of Populus alba ${\times}$ P. grandidentata hybrid clone 'Hansen'. All transgenic poplar lines possess constructs containing the bacterial nopaline synthase(nos) promoter linked to a neomycin phosphotransferase II(NPT II) selectable marker gene. In addition, each transgenic poplar line contains one of the following gene constructs : 1) a wound-inducible potato proteinase inhibitor II (pin2) promoter linked to a chloramphenicol acetyltransferase(CAT) reporter gene. 2) a nos promoter linked to a PIN2 structural gene : or 3) a Cauliflower Mosaic Virus 35s promoter linked to a PIN2 structural gene. Polymerase chain reaction(PCR) was used to verify the presence of foreign genes in the poplar genome. Enzyme-linked immunosorbent assays(ELISAs) were used to evaluate organ specific expression of the nos-NPT II construct. NPT II expression was detected in leaves, petioles, stems, and roots of transgenic poplar, thereby indicating that the nos promoter is potentially effective for general constitutive expression of transgenes. NPT expression varied among transgenic poplar lines and among organs for one transgenic line, Tr15. With Tr15, NPT II levels were highest in older leaves and petioles. These results indicate that screening of several transgenic lines may be required to identify lines with optimal transgene expression.