• The Korean Journal of Physiology and Pharmacology
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• v.9 no.2
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• pp.131-135
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• 2005

Potassium channels in human skin fibroblast have been studied as a possible site of Alzheimer disease pathogenesis. Fibroblasts in Alzheimer disease show alterations in signal transduction pathway such as changes in $Ca^{2+}$ homeostasis and/or $Ca^{2+}-activated$ kinases, phosphatidylinositol cascade, protein kinase C activity, cAMP levels and absence of specific $K^+$ channel. However, little is known so far about electrophysiological and pharmacological characteristics of large-conductance $Ca^{2+}$-activated $K^+$ ($BK_{Ca}$) channel in human fibroblast (CRL-1474). In the present study, we found Iberiotoxin- and TEA-sensitive outward rectifying oscillatory current with whole-cell recordings. Single channel analysis showed large conductance $K^{+}$ channels (106 pS of chord conductance at +40 mV in physiological $K^+$ gradient). The 106 pS channels were activated by membrane potential and $[Ca^{2+}]_i$, consistent with the known properties of $BK_{Ca}$ channels. $BK_{Ca}$ channels in CRL-1474 were positively regulated by adenylate cyclase activator ($10{\mu}M$ forskolin), 8-Br-cyclic AMP ($300{\mu}M$) or 8-Br-cyclic GMP ($300{\mu}M$). These results suggest that human skin fibroblasts (CR-1474) have typical $BK_{Ca}$ channel and this channel could be modulated by c-AMP and c-GMP. The electrophysiological characteristics of fibroblasts might be used as the diagnostic clues for Alzheimer disease.

• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.165-174
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• 2002

Vascular endothelial growth factor (VEGF) has been identified as a peptide growth factor specific for vascular endothelial cells. In this study, we examined the effect of VEGF on radiation induced apoptosis and receptor/second messenger signal transduction pathway for VEGF effect in human umbilical vein endothelial cells (HUVECs). VEGF was found to protect HUVECs against the lethal effects of ionizing radiation by inhibiting the apoptosis induced in these cells by radiation exposure. VEGF (1-30 ng/ml) dose dependently inhibited apoptosis by irradiation. Pre-treatment with Flt-1 and Flk-l/KDR receptor blocked the VEGF-in duced antiapoptotic effect. Phosphatidylinositol 3'-kinase (PI3-kinase) specific inhibitor, Wortman in and LY294002, blocked the VEGF-induced antiapoptotic effect. These data suggest that VEGF may play an important role in survival of HUVECs due to the prevention of apoptotic cell death caused by some stresses such as ionizing radiation.

• Korean Journal of Cognitive Science
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• v.19 no.3
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• pp.283-295
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• 2008

With increasing usages of a messenger and a SMS, many young people are habitually using a new-style of sentences with intentionally disjoint Korean syllables. To develop a natural language interface system in these environments, we should first develop a technique that converts a sequence of disjoint Korean syllables to a correct sentence. Therefore, we propose a method to assemble a sequence of disjoint Korean syllables into a correct sentence by using two-step rules. In the first step, the proposed method assembles CVC (consonant-vowel-consonant) forms of simple-disjoint Korean syllables by using manual heuristic rules. In the second step, the proposed method assembles CCVCC forms of double-disjoint Korean syllables by using a mapping table and a transformation-based learning technique. In the experiment, the proposed method showed the perfect precision of 100% in assembling simple-disjoint Korean syllables and the high precision of 99.98% in assembling double-disjoint Korean syllables.

• Journal of Advanced Navigation Technology
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• v.13 no.2
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• pp.280-286
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• 2009

A policy of instant messaging usage is offered in this article. First, a brief introduction of instant messaging system structure is described. The main threats and vulnerabilities of Instant messenger (IM) are described in the second part of the paper. Instant messaging applications offer so many advantages in so many different fields that they're fast becoming the preferred communication tool for a number of different professional scenarios. When properly implemented, instant messaging can be a true asset to the business by making communications easier throughout the organization. If instant messaging is carelessly implemented, though, it can cause problems with privacy and may expose the organization to various forms of malware. The solution offered in this paper is one of the effective ways against threats of IM. However, the system cannot be secured entirely. All we can do is reducing the risks.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.137-142
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• 2008

Ceramide has emerged as a novel second messenger for intracellular signalling. It is produced from sphingomyelin and is involved in the control of cell differntiation, proliferation, and apoptosis. $C_2$-ceramide, short chain ceramide, plays a role in mediating contraction of cat esophageal smooth muscle cells. We examined the effect of synthesized ceramide analogues on the $C_2$-ceramide and ACh-induced contraction in esophageal smooth muscle cells isolated with collagenase. CY3523, CY3525, or CY3723 inhibited $C_2$-ceramide induced contraction, in a time dependent manne. Each analogue also inhibited the contraction in concentration dependent manners. CY 3523, CY 3525, and CY 3723 had no effect to the contraction induced by PMA. The inhibition with CY3523, CY3525 and CY3723 on the $C_2$-ceramide induced contraction was recovered by PMA. These analogues decreased the density of MAPK bands (p44/42 or p38) in the western blot. These results suggest that ceramide analogues can inhibit $C_2$-ceramide induced contraction via PKC and MAPK dependent pathway.

• Journal of the Korean Home Economics Association
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• v.40 no.6
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• pp.1-19
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• 2002

This study is to observe the meaning, aesthetic formative nature of the human body which has been not only a main issue and discussion object but also socially, culturally connected with clothing by contemplating it in the respect of the trend of art. Additionally, a work of contemplation about human body introduced to fashion design was analyzed to renew the meaning and value of the formative art inside the human body. The way and scope of this study is to contemplate the concept and meaning of human body, based on the documentary records such as art history and clothing history in the West society as a main theme. The results of the analysis were as follows: In the first place, the formative characteristics shown in the modem arts expressing the human body since 1990 which are cubism, futurism, metaphysical painting, dadaism, surrealism, pop art, happening, feminism, body art, and technology art are distortion, exaggeration and dismantling. Second, the aesthetic formative nature and meaning in the human body appear to be different according to the standard of ideal beauty of human body when we examine the expression of it from the aspect of art-history and the meaning of human body implied in it. Besides, human body is being used as a messenger which delivers the message of modem artist to other people. So the changed meaning of human body has affected the clothing and made it possible to manufacture and form new styles of clothing that have never been before. In conclusion, the human body in the modem era plays an important role as a brand-new formative medium of communication in the human society and contributes to the development which applies the aesthetic formative nature of the human body to fashion design.

• Korean Journal of Child Studies
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• v.36 no.2
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• pp.95-110
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• 2015

In this study, an analysis of the actual conditions and needs regarding elementary school teacher's levels of cooperation was conducted. This was done from the assumption that it is essential for good communication and cooperation to exist between elementary school teachers and after-school care teachers to provide the most reliable after-school care environment possible. Individual interviews with 6 elementary school teachers were conducted, and the results of the data analysis were as follows. First, the necessity for close communication and interaction between teachers was clearly established, due to the obvious advantages obtained from cooperation on supporting children and improving the teacher's levels of expertise. However, contrary to this, the elementary school teachers in fact did not have very good communication between themselves and the after-school care teachers. Second, the problems in cooperation revealed a degree of disapproval regarding the perceived independence of after-school care teacher's duties, a sense of burden arising from interaction with a large number of teachers, the lack of communication time due to the workload of elementary school teachers, and the lack of material resources. Third, teachers further stated that although they were generally interested in after-school care classes, and showed approval of the role of after-school care teachers, regular meetings, and an expansion of the current messenger systems of communication with after-school teachers are clearly needed.

• Korean Journal of Biological Psychiatry
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• v.5 no.2
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• pp.227-234
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• 1998

Objective : Many evidences suggest that patients with bipolar disorder have functional abnormalities in their postreceptor signal transduction pathways, and mood stabilizing effect of lithium is exerted by modulating this dysfunctioning system. Carbamazepine, an antiepileptic agent, is also known to be effective in the treatment and prevention of bipolar disorder. But the precise mechanism of action of the drug is still poorly understood. This study was performed to elucidate the possible therapeutic mechanism of carbamazepine. Method : The effects of chronic carbamazepine administration on protein kinase A and protein kinase C activities in frontal cortex of rat brain after 2 weeks of drug administration were measured and compared with those of control subjects. Results : Mean(${\pm}SE$) value of activity(phosphate transfer ${\mu}mol/mg$ of $protein{\cdot}min$) of protein kinase A in control and test group was $0.249563{\pm}0.036$ and $0.539853{\pm}0.078$, and that of protein kinase C was $0.654817{\pm}0.053$ and $1.146205{\pm}0.052$ respectively, being increased in test group. And differences between the two groups were statistically significant for both enzymes(protein kinase A ; p<0.01, protein kinase C ; p<0.001). Conclusion : These results show that chronic carbamazepine administration increases protein kinase A and C activities, and concerning the possible mode of therapeutic action in bipolar disorder it is suggested that enhanced enzymes phosphorylate receptor-G-protein-effector complexes to dampen hyperfunctioning neuronal activity and thus stabilize the system.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.3
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• pp.95-99
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• 2008

Calcium ($Ca^{2+}$) is an intracellular second messenger associated with neuronal plasticity of the central nervous system. The calcium-binding proteins regulate the $Ca^{2+}$-mediated signals in the cytoplasm and buffer the calcium concentration. This study examined temporal changes of three calcium-binding proteins (calretinin, calbindin and parvalbumin) in the medial vestibular nucleus (MVN) during vestibular compensation after unilateral labyrinthectomy (UL) in rats. Rats underwent UL, and the changes in the expression of these proteins at 2, 6, 12, 24, 48, and 72 h were examined by immuno-fluorescence staining. The expression levels of all three proteins increased immediately after UL and returned to the control level by 48 h. However, the level of calretinin showed changes different from the other two proteins, being expressed at significantly higher level in the contralateral MVN than in the ipsilateral MVN 2 h after UL, whereas the other two proteins showed similar expression levels in both the ipsilateral and contralateral MVN. These results suggest that the calcium binding proteins have some protective activity against the increased $Ca^{2+}$ levels in the MVN. In particular, calretinin might be more responsive to neuronal activity than calbindin or parvalbumin.

• The Journal of Korean Society of Virology
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• v.29 no.4
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• pp.261-269
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• 1999

The relationship between second messenger cGMP and human cytomegalovirus (HCMV) replication was investigated. First, the intracellular level of cGMP ([cGMP]i) in HCMV-infected cells was measured. The [cGMP]i increased at early times after HCMV infection, reached maximum level at 12 hr and returned to basal level at 24 hr after virus infection, while [cGMP]i in mock-infected cells remained relatively unchanged. Increasing [cGMP]i resulted in enhanced transcription of HCMV major immediate early gene. For early gene expression, cGMP had varying effect. Expression of 1.2 kb RNA decreased and 2.2 kb RNA increased with increasing cGMP, while 2.7 kb RNA gene expression was not affected. HCMV early genes are regulated by immediate early gene, and the effect of cGMP on the regulatory effect of major immediate early gene on early genes was investigated. In the absence of cGMP, major immediate early gene repressed 2.7 kb RNA gene expression, while 1.2 kb RNA and 2.2 kb RNA early genes were not significantly affected. In the presence of $1\;{\mu}M$ cGMP, however, major immediate early gene stimulated the expression of three early genes.