• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.508-513
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• 2011

Hemp is known as one of the most productive and useful plants, which grows quickly in a moderate climate with only moderate water and fertilizer. Traditionally in Korea, hemp bast is used to natural fibres, and remaining such as stem and root is treated as waste. Those of hemp by-products can be transformed to bio fuel such as bio-oil and activated carbon. To understand pyrolysis characteristics, thermogravimetric analysis were carried out in TGA, in which hemp by-products were mostly decomposed at the temperature range of $270{\sim}370^{\circ}C$. The corresponding kinetic parameters including activation energy and pre-exponential factor were determined by differential method over the degree of conversions. The values of activation energies for pyrolysis were increased as the conversion increased from 10 to 90%.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.1-9
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• 2024

Exosomes are nano-sized membrane-bound extracellular vesicles containing various biological molecules, such as nucleic acids, proteins, and lipids, which can be used to modulate physiological processes. The exosomal molecules secreted by cells can be extensively used as tools for diagnosis and therapy. Exosomes carry specific molecules released by the cells they originate from, which can be transferred to surrounding cells or tissues by the exosome. For these reasons, exosomes can be exploited as biomarkers for diagnosis, carriers for drug delivery, as well as therapeutics. In stem cell technology, exosomes have been an attractive option because they can be used as safer therapeutic agents for stem cell-based cell-free therapy. Recently, studies have demonstrated the safety and efficacy of mesenchymal stem cell-derived exosomes in alleviating symptoms associated with coronavirus disease 2019 as they have anti-inflammatory and immunomodulatory potential. Performing multiple studies on exosomes would provide innovative next-generation options for clinical diagnostics and therapy. This review summarizes the use of exosomes focusing on their diverse roles. In addition, the potential of exosomes is illustrated with a focus on how exosomes can be exploited as powerful tools in the days to come.

• Journal of Technology Innovation
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• v.28 no.3
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• pp.55-76
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• 2020

The traditional occupational boundaries of human resources in science and technology (S&T) have quickly blurred in Korea. On the one hand, the knowledge-based economy has emerged and S&T proliferated beyond conventional areas, leading scientists and engineers to advance into various convergence fields. On the other hand, Korea's labor market is characterized by a higher percentage of highly-educated human resources and a relatively smaller number of high-quality jobs. As a result, the highly educated in S&T have flowed over the traditional careers into non-S&T careers. Focusing on doctorates in S&T, this paper analyzes changes in their career patterns and identifies main determinants. Specifically, jobs are categorized into traditional STEM occupations and the others in order to identify fluctuations in their share and to analyze factors affecting such changes. The analyses are based on data from the 'Survey on Careers and Mobility of Doctorate Holders 2012' conducted by the Science and Technology Policy Institute. The results exhibit marked changes in the occupational composition of doctorates in S&T. Occupational diversification has been proceeded faster in natural sciences, the private sector, and the younger generation than in engineering, the public sector, and the older generation.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.383-390
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• 2016

Mesenchymal stem cells (MSCs) are multipotent stem cells that can be differentiated into a variety of cell types, including adipocytes, osteoblasts, chondrocytes, β-pancreatic islet cells, and neuronal cells. MSCs have been reported to exhibit immunomodulatory effects in many diseases. Many studies have reported that MSCs have distinct roles in modulating inflammatory and immune responses by releasing bioactive molecules. Exosomes are cell-derived vesicles present in biological fluids, including the blood, urine, and cultured medium of cell cultures. In this study, we investigated the immunomodulatory effects of mouse adipose tissue-derived MSCs (mAD-MSCs), cultured medium (MSC-CM) of mAD-MSCs, and mAD-MSC-derived exosomes (MSC-Exo) on lipopolysaccharide (LPS)-induced RAW 264.7 cells. We observed that the expression levels of IL-1β, TNF-α, and IL-10 were significantly increased in LPS-stimulated RAW 264.7 cells compared to those in LPS-unstimulated RAW 264.7 cells. Additionally, these values were significantly (p < 0.05) decreased in mAD-MSCs-RAW 264.7 cell co-culture groups, MSC-CM-treated groups, and MSC-Exo-treated groups. MSCs can modulate the immune system in part by secreting cytokines and growth factors. We observed that immunomodulatory factors such as IL-1β, TNF-α, and IL-10 were secreted by mAD-MSCs under co-culturing conditions of mAD-MSCs with activated RAW 264.7 cells. In addition, mAD-MSC-derived exosomes exhibited similar immunomodulatory effects in activated RAW 264.7 cells. Therefore, our results suggest that mAD-MSCs have an immunomodulatory function through indirect contact.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.193-204
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• 2009

The importance of corporate identity design has been recently highlighted in the marketing. However, logotype among marks that represent the image of a company has been neglected relatively comparing to symbol mark and logo mark. A logotype should be something to represent the personalities and characteristics of a company in suggestive ways. For such reasons, the image expressions by shape are thought to be important. Consequently, the formative aspects of visual communication design should be examined with emphases. However, it is true that studies on the formative aspects regarding logotypes and logo marks, especially studies on the shapes of font types and the responses of consumers to them, are lacking. Accordingly, this study examined the visual shape of logotype preferred by consumers and the shape of logotype preferred by consumers according to the business type of companies. As a result of research, there were differences in the elements of logotype preferred according to the business type of companies; as for construction companies is preferred the body of the type of dotum font with bold stem, without serif, with oblique, straight-line and curve-line endings; as for banks is preferred the body of the type of dotum font without serif, with oblique ending and with one-side curve style of serif, the stem in a middle level; as for laboratories is preferred the body of the type of dotum font with oblique ending, with bold stem and straight-line serif. The elements that should be commonly applied to construction companies, banks and laboratories appear to be the oblique ending but the curve-line ending and shallow stem seemed to be avoided. On the other hand, the serif, ending and gulim appeared to be applied differently according to the business type.

• Journal of Veterinary Clinics
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• v.27 no.5
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• pp.533-539
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• 2010

Stem cell-based therapy is under intensive investigation to treat acute renal failure (ARF). The purpose of this study was to evaluate available ARF models, and suggest a model appropriate to therapeutic evaluation of the stem cells in preclinical approach by determining the optimum concentration of nephrotoxic agents and duration of ischemia induction. Three different types of available acute kidney injury (AKI) animal models were analyzed using rats: Cisplatin (saline, 5 and 7.5 mg/kg, IP) or glycerol (saline, 8 and 10 ml/kg, IM)-induced nephrotoxicity as toxic models and ischemia-induced (sham, 35 and 45 minutes) nephropathy as an ischemic model. The relevance and applicability to investigate especially the regenerative ability of stem cells were evaluated regarding morphology, renal function and survival at this time point. In the point of renal function, 10 ml glycerol/kg and 7.5 mg cisplatin/kg model in toxic models and 45 min model in ischemia models showed significant decrease for the longer observation time compared to 8 ml glycerol/kg, 5 mg cisplatin/kg and the 35 min ischemia models, respectively. All groups were observed no mortality except 45 min-ischemia model with 50% survival. Histological significant alterations including cast formation in the tubular lumen, tubular necrosis and apoptosis were revealed on the second day in either ischemiaor glycerol-induced models, and on day 5 in cisplatin-induced models. The results indicate that ischemia 35 min-, cisplatin 7.5 mg/kg- and glycerol 10 ml/kg-induced AKI would be ideal animal models to monitor a outcome parameter related to the therapeutic effects on renal function with noninvasive techniques in the same animal at multiple time points. Our findings also suggest that the best time points for the functional or histological interpretation of renal will be on day 2 in both glycerol- and ischemia-induced AKI models and on day 5 in cisplatin-induced AKI.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.686-689
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• 2008

In the past decade, various data mining techniques have been used in construction engineering as a means to make informed decisions through the aid of useful knowledge discovered from historical data. Researchers in the construction domain are often confronted with a challenge to derive a meaningful conclusion with a limited sample of data. However, when the data size is small, the proposed results are often illogical. Even if the derived results are technically flawless, sometimes it is difficult to reproduce these results by using the same analysis method when a different set of data is used. This paper reviews some problems that stem from limited data size, and discusses several recommendations for dealing with these problems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.66-72
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• 2020

In order to cultivate talented people with national economic influence in the rapidly changing 21st- century modern society, STEM(Science Technology Engineering Mathematics) education has been emphasized in advanced countries such as America and England. In South Korea, STEAM(Science Technology Engineering Arts Mathematics) education is emphasized by adding Arts. The objective of STEAM education is to strengthen the interest and motivation of learners, to focus on experience, exploration, experimentation, to solve convergent thinking and real-life problems, rather than cramming method of teaching and memorization. This study identifiesan instructional design for converged English, the world's official language, and science which is found in nearly all disciplines. With the development of the 4th industrial revolution based on the PBL model, learners participate in their lessons voluntarily for problem-solving skills. The instructional design based on the ADDIE model consists of 5 procedures: Analysis, Design, Development, Implementation, and Evaluation. The goal of fostering talented people with national economic influence is also important, and the teacher in education must recognize the importance of STEAM education and an appropriate instructional design should be studied constantly.

• Journal of Appropriate Technology
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• v.6 no.2
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• pp.146-150
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• 2020

Assistive technologies for people with disabilities are often marginalized in the Fourth Industrial Revolution. In this paper, we intend to present the possibility of acquiring tactile information through the tactile display adapting an electromagnetic actuator. The multi-layered display designed for tactile communication has innovatively narrowed the size and spacing of cells in order to express pictures, maps, and graphics. This display has enabled the visually impaired to touch two-dimensional information combining with other assistive technologies so that. It would also provide a technical source of access to STEM education (Science, Technology, Engineering, and Mathematics) so that students will perform better and be better prepared for advanced education. Moreover, it can be applied to public infrastructure and transportation in smart-city projects on the globe. Hence, this paper introduces the principle of Electromagnetic-actuator and how it can be utilized in many diverse areas.

• Communications of Mathematical Education
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• v.29 no.3
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• pp.553-571
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• 2015

Mathematical, verbal, and spatial abilities are known as three important indicators for the success in the STEM disciplines. In this study, Purdue Spatial Visualization Test-Rotation, College Entrance Scholastic Aptitude Test- Math and Verbal score of engineering freshmen students have been used to find the relationships among these areas. In addition, gender differences in spatial visualization, verbal achievement and mathematical achievement have been investigated, too. In this research, I found that gender difference was highest in spatial visualization ability, followed by verbal achievement and smallest in mathematical achievement. Substantial number of male students possess high level of spatial abilities, but only half of female students were at the same level where their male colleagues were. The correlation between spatial ability and mathematical ability was negligible, contrary to former researches on elementary and middle school students. But the correlation was stronger for female students than male students. The correlation between mathematical achievement and verbal achievement was negative. It reflects the fact that when one section of SAT score is low, score of other sections should be higher to get admitted to college. Gender difference in mathematics was smallest for high achieving spatial ability group. For low spatial ability group gender difference in mathematics achievement has been observed, too. To find the combined contribution of spatial and verbal abilities to mathematics achievement, students were divided into 4 ability groups. Mathematics achievement decreased in the order of (1) high spatial -low verbal group, (2) low spatial - low verbal group, (3) high spatial - high verbal group, (4) low spatial - high verbal group.