• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.180-189
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• 2017

Pharmaceutical co-crystals primarily to improve the solubility as well as stability of insoluble drug are to be investigated more intensively for IMDs as US FDA has reclassified co-crystal as a special case of solvates in August this year. In this study, we proposed a mechanism of indomethacin-saccharin co-crystal formation and the creation of transient indomethacin meta-stable form using in-line monitoring tools with the addition rate of anti-solvent as a critical process parameter. Among various instruments, we combined PVM (particle vision measurement) and FBRM (focused beam reflectance measurement) for the in-line monitoring of anti-solvent co-crystallization process. The off-line characterization of resulting powders was carried out employing the PXRD (powder x-ray diffraction) and DSC (differential scanning calorimeter). It was observed that the pathway to the final IMC-SAC co-crystal was significantly dependent upon the anti-solvent addition rate. The process conditions to obtain high quality co-crystal powder effectively were established. Consequently, we concluded that in-line monitoring combing the PVM and FBRM should be useful for the in-line monitoring of pharmaceutical co-crystallization processes.

• Elastomers and Composites
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• v.45 no.3
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• pp.170-187
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• 2010

Much interest on the thermoplastic elastomers (TPEs) has recently been attracted in commercial fields as well as scientific and applied researches. The TPEs have their own characteristic area especially in relation with block copolymers as well as many other polymeric materials, since they show interesting features displayed by the conventional vulcanized rubber, and at the same time, by the thermoplastics. In addition, they are characterized by a set of interesting properties inherent to block and graft copolymers, variety of blends and vulcanized materials. The importance of TPE as organic materials can be evaluated by the number of published reports (papers, patents, technical reports, etc). The input of the concept 'thermoplastic elastomer' to SciFinderScholar yields 18,508 results between 1939 and July 10, 2010, and the number increased exponentially after the mid of 1990. For the suitable introduction of the TPE, historic, scientific, technical and commercial considerations should be taken into account. This review article starts with a brief discussion on historical considerations, followed by a introduction of the main preparations and analytical techniques utilized in chemical, structural, and morphological studies. The properties, processing tools, the position among organic materials, and applications of TPEs are also briefly reviewed. Finally, the most probable trends of their future development are discussed in a short final remarks.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.215-221
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• 2010

Salmonella is an important food-and water-borne pathogen associated with acute gastrointestinal illnesses around the world. The most common serotypes isolated from humans are Salmonella enterica serotype Typhimurium (S. Typhimurium) and S. Enteritidis. Traditional detection methods for Salmonella are based on cultures using selective media and characterization of suspicious colonies by biochemical and serological tests. These methods are generally time-consuming and not so highly sensitive. Recently, the Loop Mediated Isothermal Amplification and real-time PCR has been used as a highly sensitive, specific, and rapid test for the presence of pathogenic bacteria. In this study, a LAMP and real-time PCR was used to detect S. Typhimurium and S. Enteritidis. We selected target genes, which were the in invA and a randomly cloned sequence specific for the genus Salmonella. With LAMP and real-time PCR, random sequence was detected from Salmonella spp, invA were detected from all strain of S. Typhimurium and S. Enteritidis. This assay indicate that the specificity, sensitivity and rapid of the LAMP and real-time PCR make them potentially valuable tools for detection of S. Typhimurium and S. Enteritidis.

• KSBB Journal
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• v.22 no.6
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• pp.409-413
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• 2007

Polydiacetylene(PDA)-based sensors possess a number of properties that can be successfully applied for label-free detection system. PDA is one of the most attractive color-generating materials, with growing applications as sensors. Here we introduce various PDA-based devices, used as biosensor, chemosensor, thermosensor, and optoelectronics sensor. In general, PDA liposomes and films are closely packed and properly designed for polymerization via 1,4-addition reaction to form an ene-yne alternating polymer chain. PDA-based two/three dimensional structures have been used for colorimetric or fluorescent devices, sensing biological as well as chemical components. This color-generating material also present a very high charge carrier mobility, allowing its application as field-effect transistor (FET). The immobilized PDA structures or films have distinct advantages for the detection of low concentration target molecules over the aqueous solution-based detection systems. In the present review, reported detection methods by using various PDA structures are summarized with updated references.

• Journal of the Korean Chemical Society
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• v.63 no.3
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• pp.166-182
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• 2019

This study examined teachers' difficulties that they encountered free semester science assessment and their problem solutions. Fifteen science teachers who had experiences of free semester teaching and assessment were selected by convenience sampling in this study. The participant teachers mentioned difficulties of accurate scoring in student self/peer assessment and suggested solutions of providing studetns with detailed assessment criteria and opportunities to practice assessment. The participant teachers mentioned a lack of objective assessment criteria for affective domain and suggested solutions of providing criteria prior to assessment and developing assessment framework. The participant teachers mentioned a lack of assessment tools and references for perforamnce assesement. The participant teachers mentioned difficulties of a large teacherstudent ratio for providng feedbacks to students and suggested solutions of decreasing teacher-student ratio and teaching load. The participant teachers mentioned difficulties of identifying student characteristics for assessment reporting and suggested solutions of decreaing teacher work load. The participant teachers mentioned a lack of teacher understanding of process based assessment and inactive attitude to performance assessment and suggested solutions of professional learning community and improving teacher perceptions on performance assessment. The participant teachers mentioned difficulties of a large teacher-student ratio and a lack of time for implementing assessment methods that they learned from professional development programs. With both teacher self-efforts and systematic support, these problems would be solved and success of free semester assessment would be achieved.

• Nutrition Research and Practice
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• v.17 no.4
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• pp.682-697
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• 2023

BACKGROUND/OBJECTIVES: Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice. MATERIALS/METHODS: The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH2O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected. Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method. RESULTS: The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism. CONCLUSIONS: This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.

• Journal of the Korean Chemical Society
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• v.68 no.2
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• pp.93-106
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• 2024

This study investigated differences in presence, immersion, and situational interest in small group learning using augmented reality, based on the degree of tool sharing. 84 eighth-grade students participated in small groups of four. Each group was randomly assigned to one of three environments based on marker and device sharing: the shared environment (shared marker and device usage), the mixed environment (shared marker and individual device usage), and the individual environment (individual marker and device usage). Small group learning using augmented reality was conducted for three class periods, focusing on the "Characteristics of Matter" unit. One-way ANOVA results for the dependent variables revealed that, compared to the shared environment, presence and situational interest were significantly higher in the mixed environment, while immersion and situational interest were significantly higher in the individual environment. MANOVA results for the sub-components of each dependent variable showed significant differences in realness for presence, antecedents and experiences for immersion, and instant enjoyment, novelty, and total interest for situational interest. Analysis of interviews and classroom observations indicated that students in shared and individual environments tended to use their devices individually when utilizing augmented reality. However, in mixed environments, students showed a tendency to use their devices collaboratively, leading to more active interactions. Based on these findings, environments for using tools to enhance the effectiveness of small group learning using augmented reality are discussed.

• Journal of the Korean Chemical Society
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• v.68 no.3
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• pp.160-175
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• 2024

The purpose of this study is to examine the effects of a Chemistry I class based on an artificial intelligence (AI) classification model. To achieve this, the research investigated the development and application of a class utilizing an AI classification model in Chemistry I classes conducted at D High School in Gyeongbuk during the first semester of 2023. After selecting the curriculum content and AI tools, and determining the curriculum-AI integration education model as well as AI hardware and software, we developed detailed activities for the program and applied them in actual classes. Following the implementation of the classes, it was confirmed that students' self-efficacy improved in three aspects: chemistry concept formation, AI value perception, and AI-based maker competency. Specifically, the chemistry classes based on text and image classification models had a positive impact on students' self-efficacy for chemistry concept formation, enhanced students' perception of AI value and interest, and contributed to improving students' AI and physical computing abilities. These results demonstrate the positive impact of the Chemistry I class based on an AI classification model on students, providing evidence of its utility in educational settings.

• Journal of The Korean Association For Science Education
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• v.32 no.1
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• pp.64-81
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• 2012

The purpose of this study was to analyse middle school students' images and perceptions about scientist, technician and engineer and to compare the images of male students with those of female students. Fralick et al.(2009)'s "Draw a scientist at work and draw an engineer at work" was modified and administered to 110 middle school 3rd grade students (43 male students, 67 female students) from 5 middle schools. They drew the figures at work and took explanation of what the person was doing in a drawing. The results of this study were as follows; First, the representative image of scientist was the man with glasses and lab gown performing the chemical experiment. There were no significant differences between the male students and female students in terms of the scientist images. Second, the representative image of technician was the man who was fixing a car and working with his hands. The technicians were illustrated as working with tools such as wrench, hammer and so on. There were no significant differences between the male students and female students in terms of the technician images. Third, the students involved in this study frequently perceived male engineers as working indoors. But perceptions about performance of engineers were significantly different between male students and female students. A majority of male students recognized that engineers should design, invent and create the products, however many female students perceived the engineers as car mechanics. Fourth, the students perceived differently the scientists' task compared with the technicians', but they had difficulty in distinguishing the scientists' task from the engineers' task.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.745-756
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• 2020

An ICS(industrial control system) is a complex system that safely and efficiently monitors and controls industrial processes such as electric power, water treatment, transportation, automation plants and chemical plants. Because successful cyber attacks targeting ICS can lead to casualties or serious economic losses, it becomes a prime target of hacker groups sponsored by national state. Cyber campaigns such as Stuxnet, Industroyer and TRITON are real examples of successful ICS attacks, and were developed based on the deep knowledge of the target ICS. Therefore, for incident investigation of ICSs, inspectors also need knowledge of control processes and accident investigation techniques specialized for ICSs. Because there is no applicable technology, it is especially necessary to develop techniques and tools for embedded controllers located at cyber and physical boundaries. As the first step in this research, we reviewed logging capability of 4 PLC(Programmable Logic Controller)s widely used in an ICS area, and checked whether selected PLCs generate logs that can be used for digital investigation in the proposed cyber attack scenario.