• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.19-29
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• 1996

The neurological manifestations of AIDS include dementia, encountered even in the absence of opportunistic superinfection or malignancy. The AIDS Dementia Complex appears to be associated with several neuropathological abnormalities, including astrogliosis and neuronal injury or loss. How can HIV-1 result in neuronal damage if neurons themselves are only rarely, if ever, infected by the vitus\ulcorner In vitro experiments from several different laboratiories have lent support to the existence of HIV- and immune-related toxins. In one recently defined pathway to neuronal injury, HIV-infected macrophages/microglia as well as macrophages activated by HIV-1 envelope protein gp120 appear to secrete excitants/neurotoxins. These substances may include arachidonic acid, platelet-activating factor, free radicals (NO - and O$_2$), glutamate, quinolinate, cysteine, cytokines (TNF-${\alpha}$, IL1-B, IL-6), and as yet unidentified factors emanating from stimulated macrophages and possibly reactive astrocytes. A final common pathway for newonal suscepubility appears to be operative, similar to that observed in stroke, trauma, epilepsy, and several neurodegenerative diseases, including Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This mechanism involves excessive activation of N-methyl-D-aspartate (NMDA) receptor-operated channels, with resultant excessive influx of Ca$\^$2+/ leading to neuronal damage, and thus offers hope for future pharmacological intervention. This chapter reviews two clinically-tolerated NMDA antagonists, memantine and nitroglycerin; (ⅰ) Memantine is an open-channel blocker of the NMDA-associated ion channel and a close congener of the anti-viral and anti-parkinsonian drug amantadine. Memantine blocks the effects of escalating levels of excitotoxins to a greater degree than lower (piysiological) levels of these excitatory amino acids, thus sparing to some extent normal neuronal function. (ⅱ) Niuoglycerin acts at a redox modulatory site of the NMDA receptor/complex to downregulate its activity. The neuroprotective action of nitroglycerin at this site is mediated by n chemical species related to nitric oxide, but in a higher oxidation state, resulting in transfer of an NO group to a critical cysteine on the NMDA receptor. Because of the clinical safety of these drugs, they have the potential for trials in humans. As the structural basis for redox modulation is further elucidated, it may become possible to design even better redox reactive reagents of chinical value. To this end, redox modulatory sites of NMDA receptors have begun to be characterized at a molecular level using site-directed mutagenesis of recombinant subunits (NMDAR1, NMDAR2A-D). Two types of redox modulation can be distinguished. The first type gives rise to a persistent change in the functional activity of the receptor, and we have identified two cysteine residues on the NMDARI subunit (#744 and #798) that are responsible for this action. A second site, presumably also a cysteine(s) because <1 mM N-ethylmaleimide can block its effect in native neurons, underlies the other, more transient redox action. It appears to be at this, as yet unidentified, site on the NMDA receptor that the NO group acts, at least in recombinant receptors.

• Journal of Biosystems Engineering
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• v.12 no.3
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• pp.30-41
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• 1987

The geometrical shape of a plow bottom may be the most important factor affecting the performance of a plow for a given soil and operating conditions. There are various designs of the Jaenggi (Korean plow) available commercially, which may be different from each other and from the plow (Western plow) in respect to the shape and performance. This study was intended to investigate the geometrical characteristics of Jaenggi. The coordinate digitizer equipped with 3 potentiometers was designed and manufactured for measurement of the shape of curved plane of moldboard and share. The digitizer was connected to a microcomputer having the data acquisition system. This device was used to analyze the plow bottoms of 5 differently-made Jaenggis and one cylindrical plow. The results of the study are summarized as follows: 1. It was possible to measure easily and quickly the curved plane of plow bottom and to plot the view on three major plans using the coordinate digitizer electrically connected to a microcomputer system. 2. The shape of five Jaenggi bottoms analyzed could be characterized by the cutting angle having the range of $33-42^{\circ}$, the maximum share-lift angle of $41-50^{\circ}$, and the setting angle of moldboard wing of $46-70^{\circ}$. The most critical difference of the shape factors between the Jaenggi and the plow was found in the maximum share-lift angle, the former was more than twice as much as the latter. 3. The analysis of the shape of Jaenggi bottoms showed that the share projections on 3 major plans had a varied triangle, which was quite different from that of plow bottom. Especially, it was analyzed that the shape of furrow slice for the Jaenggi had a skewed rectangle, leaving a considerable height of the ridge at the furrow bottom. 4. The dihedral angle was similar range of $30-85^{\circ}$ for the all bodies investigated, but the directional angle was somewhat different from each other. The difference in directional angle was $5^{\circ}$ for the plow, $20^{\circ}$ for the Jaenggi A and $30^{\circ}$ for the Jaenggi B. 5. Area of the spherical representation region was 0.0328 for the plow, 0.1194 for the Jaenggi A and 0.1716 for the Jaenggi B. This may indicate that the plow came close to a working surface and the Jaenggi A and the Jaenggi B departed from a working surface to a somewhat greater extent.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.213-220
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• 2021

The purpose of this study is to pave the way to promote the institutional commitment of the students enrolled by identifying the factors that affects on their institutional commitment. The data collection was conducted starting from November 19, 2020 until November 26, 2020 by using online questionnaires and 220 participants were from C-university students in Chang-won, Kyung-nam Province. As a result of analysis, the average score for institutional commitment was 3.30, the average level of satisfaction of university life was 3.62, the cultural climate was 3.39 and the level of satisfaction for extracurricular program was 3.48, which was in high range. Institutional commitment has a positive correlation between the level of satisfaction of university life, the level of satisfaction for extracurricular programs(p<.001). The most critical factor that affects the institutional commitment was the level of satisfaction of university life and the level of satisfaction for extracurricular programs, the cultural climate in order. The result can be interpreted that institutional commitment is influenced by students' major and the level of satisfaction of university life and the level of satisfaction for extracurricular programs, and the level of satisfaction of university life has relatively high level of influence out of other factors, indicating that the effort to improve the institutional commitment of the students is needed at the collegiate level.

• Journal of Distribution Science
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• v.11 no.6
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• pp.81-89
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• 2013

Purpose - The market orientation of a manufacturer is a very critical competitive advantage factor in the development of new markets and the sustainability and maintenance of existing ones, achieved through the design of customer-oriented products. This is recognized as a virtuous circle, in which firms grow by means of promoting quality management. However, though market-oriented activities are important in management and operations, they seem to be promoted mainly by large-scale enterprises rather than by small- and medium-scale firms, the latter having invested relatively few company resources. Furthermore, few studies and analyses have examined how market orientation relates to the expansion of quality programs within organizations or with business performance; the market orientation and customer-orientation concepts are mixed together when both are used in research. Given the current market situation in which the servitization of manufacturing firms is rapidly expanding, this study's analysis of the effect on market orientation of manufacturers is a significant contribution. From this perspective, this study has several objectives. First, is to analyze and suggest the relationship between market orientation and quality management activity for manufacturers, focusing on three sub-activities: products, process, and quality management activities. Second, it is intended to identify correlation between manufacturers' market oriented activity and their management performance and then to analyze how market orientation affects business performance. The results of a number of prior studies on the correlation between market orientation and management performance have indicated that market orientation does affect management performance. Third, this study also investigates whether any differences in the relationship among market orientation, quality management activity and business performance occur according to company size. The results are used to present operational suggestions for large- and small- and medium-size firms. Research design, data, methodology - This study seeks to analyze and identify the causal features of the organic relationship among market orientation, quality management, and management performance for Korean manufacturing companies using three years (2005-2007) of market orientation, quality management, and business performance data. Subsequently, structural equation modeling was used to analyze the causal features of related factors and it aims to identify the features of market orientation, quality management, and business performance. Results - The analysis examined how market orientation affected the quality management and management performance of 159 smalland medium-size companies. In particular, enterprise quality management was analyzed in relation to management performance with a focus on activities such as leadership, measurement and improvement, quality control, cost management, and process management. Conclusions - The result of the analysis show that market orientation significantly affected all of the quality management activities and that market orientation in turn significantly affected organizational performance. The result of analysis indicate that quality management activities have a significant effect on quality control and cost management.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2629-2633
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• 2012

Background: Raw betel nut (RBN) chewing is an important contributing factor for esophageal squamous cell carcinoma (ESCC), although associated genomic changes remain unclear. One difficulty in assessing the effects of exclusively RBN induced genetic alterations has been that earlier studies were performed with samples of patients commonly using tobacco and alcohol, in addition to betel-quid. Both CDKN2A (at 9p21) and Rb1 gene (at 13q14.2) are regarded as tumor suppressors involved in the development of ESCC. Therefore, the present study aimed to verify the RBN's ability to induce ESCC and assess the involvement of CDKN2A and Rb1 genes. Methods: A panel of dinucelotide polymorphic markers were chosen for loss of heterozygosity studies in 93 samples of which 34 were collected from patients with only RBN-chewing habit. Promoter hypermethylation was also investigated. Results: Loss in microsatellite markers D9S1748 and D9S1749, located close to exon $1{\beta}$ of CDKN2A/ARF gene at 9p21, was noted in 40% ESCC samples with the habit of RBN-chewing alone. Involvement of a novel site in the 9p23 region was also observed. Promoter hypermethylation of CDKN2A gene in the samples with the habit of only RBN-chewing alone was significantly higher (p=0.01) than Rb1 gene, also from the samples having the habit of use both RBN and tobacco (p=0.047). Conclusions: The data indicate that the disruption of 9p21 where CDKN2A gene resides, is the most frequent critical genetic event in RBN-associated carcinogenesis. The involvement of 9p23 as well as 13q14.2 could be required in later stages in RBN-mediated carcinogenesis.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.241-250
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• 2011

The most part of vegetable oils is accumulated as storage lipid, triacylglycerol (TAG) in seed and used as energy source when seed is germinated. It is also used as essential fatty acids and energy source for human and animal. Recently, vegetable oils have been more and more an important resource because of the increasing demand of vegetable oils for cooking and industrial uses for bio-diesel and industrial feedstock. In order to increase vegetable oils using biotechnology, over-expressing or repressing the regulatory genes involved in the flow of carbon into lipid biosynthesis is critical during seed development. In this review, we described candidate genes may influence oil amount and investigate their potential for oil increase. Genes involved in the regulation from biosynthesis of fatty acids to the accumulation oils in seed can be classified as follows: First, genes play a role for synthesis precursor molecules for TAG. Second, genes participate in fatty acid biosynthesis and TAG assembly. Lastly, genes encodes transcription factors involved in seed maturation and accumulation of seed oil. Because factors/genes determining oil quantity in seed is complex as mentioned, recently regulation of transcription factors is being considered more favorable approach than manipulate multiple genes for increasing oil in transgenic plants. However, it should be figured out the problem that bad agricultural traits induced by the overexpression of transcription factor gene.

• Korean Journal of Animal Reproduction
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• v.7 no.2
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• pp.57-71
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• 1983

1. Diluted chicken semen can be preserved at 2 to 5$^{\circ}C$ for 24 to 48 hr with resultant fertility of greater than 90% of that of fresh semen. Turkey semen can be preserved at 10 to 15$^{\circ}C$ for 6 to 24 hr and provide economical fertility. 2. Frozen chicken semen has given variable results; a 21 to 93% fertility ranges as compared to 92 to 94% expected with fresh semen. Highest fertility levels obtained with frozen turkey semen intravaginally inseminated have been 61 and 63% using DMSO and glycerol, respectively, as cryoprotectants. 3. The use of glycerol as a cryoprotectant reauires that its concentration in semen be reduced to less than 2% either by dialysis or centrifugation after thawing and before intravaginal insemination if optimal fertility is to be obtained. 4. The temperature at which cryoprotectants are added to semen and the time allowed for equilibration are important for subsequent fertility pre- and post-freezing. 5. The type of container used for packaging the semen, freeze or cooling rates, thaw rates and level of cryoprotectant all interact in affecting cell survival. 6. Plastic freeze straws as a packaging device for semen offers the following advantages: easy to handle, require minimal storage space, offer a wide range of freeze and thaw rates, and insemination can be made directly from them upon thawing. 7. Controlled slow cooling rates of 1 to 8$^{\circ}C$/min have thus far provided the best results for cooling chicken semen throught the transition phase change (liquid to solid) or critical temperature range of ＋5 to -20 or -35$^{\circ}C$. 8. Highest fertilities have been achieved with frozen chicken semen where a slow thaw rate (2。 to 5$^{\circ}C$) has been used regardless of the freeze rate. 9. To maintain a constant high level of fertility throughout a breeding season with frozen semen, a higher absolute number of spermatozoa must be inseminated (2 to 3 times as many) as compared to fresh semen since a, pp.oximately 50% are destroyed during processing and freezing. 10. The quality of semen may vary with season and age of the male. Such changes in sperm quality could be accentuated by storage effects. Thus, the correct number of spermatozoa may very well vary during the course of a breeding period. 11. As to time of insemination, it is best to avoid inseminating chicken hens within 1-2 hr after or 3-5 hr before oviposition; and turkey hens during or 7-10 hr before oviposition. 12. The physiological receptiveness of the oviduct at the time of insemination is a very important biological factor influencing fertility levels throughout the breeding season.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.1
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• pp.31-37
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• 2013

Purpose: Maxilla and mandible have different patterns of cortical and trabecular bone and different bone mineral densities, even though both are components of the jaw bone. However, cellular differences between maxilla- and mandible derived osteoblasts (OBs) have rarely been studied. We hypothesize that maxilla- and mandible-derived OBs show different responses to $17{\beta}$-estradiol (E2), which is one of the critical factors for bone formation. This study compares skeletal site-specific cell responses between maxilla- and mandible-derived human OBs to E2. Methods: Maxilla- and mandible-derived OBs derived from an identical donor were separately isolated from a total of five normal healthy subjects aged 18~44 years old, cultured with a treatment of 100 nM estrogen. The responses between maxilla- and mandible-derived OBs to E2 were evaluated and compared using cell proliferation, alkaline phosphatase (ALP) activity and gene expression of osteoprotegerin (OPG), ALP, insulin-like growth factor-1 (IGF-1), and estrogen receptor ${\alpha}$ ($ER{\alpha}$). Results: E2 did not have any distinct effects on the proliferation of both types of OBs. Mandible-derived OBs exhibited higher ALP activity than maxilla-derived OBs in the non-treated condition, which was common in all tested individuals. ALP activities of both types of OBs showed a minor increasing tendency with the treatment of E2, even though there was no statistical significance in some specimens. The gene expression of OB by E2 was diverse, depending on the individuals. There was increased expression of OPG, IGF-1, or $ER{\alpha}$ gene in the part of subjects, which was more repeated in maxilla-derived OBs. In particular, OPG or ALP induction by E appeared less frequently in mandible-derived OBs. Conclusion: Current results revealed that E2 affects maxilla- and mandible-derived OBs into facilitating the osteogenic process despite individual differences. Mandible-derived OBs are less sensitive to bone-forming gene expression by E2.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.28-32
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• 2009

Silicon carbide (SiC) is a promising material for power device applications due to its wide band gap (3.26 eV for 4H-SiC), high critical electric field and excellent thermal conductivity. The Schottky barrier diode is the representative high-power device that is currently available commercially. A field plate edge-terminated 4H-SiC was fabricated using a lift-off process for opening the Schottky contacts. In this case, Ni/Ti dual-metal contacts were unintentionally formed at the edge of the Schottky contacts and resulted in the degradation of the electrical properties of the diodes. The breakdown voltage and Schottky barrier height (SBH, ${\Phi}_B$) was 107 V and 0.67 eV, respectively. To form homogeneous single-metal Ni/4H-SiC Schottky contacts, a deposition and etching method was employed, and the electrical properties of the diodes were improved. The modified SBDs showed enhanced electrical properties, as witnessed by a breakdown voltage of 635 V, a Schottky barrier height of ${\Phi}_B$=1.48 eV, an ideality factor of n=1.04 (close to one), a forward voltage drop of $V_F$=1.6 V, a specific on resistance of $R_{on}=2.1m{\Omega}-cm^2$ and a power loss of $P_L=79.6Wcm^{-2}$.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.121-131
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• 2024

Purpose : This study aimed to investigate the leisure satisfaction of participants in the Geod-Jyu walking program and to examine the relationship between health promotion behaviors and quality of life. In addition, we investigated the impact of leisure satisfaction with walking among program participants on health promotion behaviors and quality of life. By clarifying these relationships, we aimed to identify factors of leisure satisfaction with walking that could enhance participants' health promotion behaviors and quality of life. Methods : A survey was conducted among 301 participants enrolled in the Geod-Jyu walking program in Chungcheongnam-do, with 288 responses analyzed. Data analysis included Pearson's correlation, confirmatory factor analysis, and multiple regression analysis using SPSS 27.0. Result : Leisure satisfaction exhibited a positive correlation with health promotion behavior (r=.544, p<.01) and quality of life (r=.478, p<.01). Furthermore, health promotion behavior showed a positive correlation with quality of life (r=.636, p<.01). Leisure satisfaction positively influenced quality of life, with physiological satisfaction (β=.16, t=2.32) and relaxation satisfaction (β=.15, t=2.04) emerging as notable contributors. In addition, leisure satisfaction had a significant positive impact on health promotion behaviors, with psychological satisfaction (β=.24, t=3.09) and educational satisfaction (β=.20, t=3.09) playing key roles. Health promotion behavior had a positive impact on quality of life, with all sub variables exhibiting significant positive effects in the following order: self-actualization (β=.24, t=4.16), stress management (β=.22, t=3.97), exercise (β=.22, t=4.05), and health responsibility (β=.12, t=2.14). Conclusion : The findings indicate that factors related to physical and rest satisfaction, as well as health-promoting behaviors facilitated by walking, significantly affected the quality of life among Geod-Jyu participants. Thus, promoting leisure satisfaction and engaging in health-promoting activities through walking can enhance overall well-being. Encouraging participation in the Geod-Jyu walking program is critical for physical and psychological benefits, and for promoting healthier behaviors. Further development of Geod-Jyu is expected to enhance walking satisfaction, promote self-care skills for health management, and positively influence quality of life.