• Proceedings of the PSK Conference
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• 2003.04a
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• pp.160.1-160.1
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• 2003

Persistent organic pollutants (POPs) have spread throughout the global environment to threaten human health and damage ecosystems. with evidence of POPs contamination in wildlife, human blood. and breast milk documented worldwide. Breast milk is an ideal medium for assessing exposures to POPs. POPs enter humans largely as contaminants of dietary animal products, where they sequester in adipose tissue, serum, and breast milk and equilibrate at similar levels on a fat weight basis. (omitted)

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.31-36
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• 2013

The present study was undertaken to investigate the influence of eupatilin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Eupatilin more significantly relaxed fluoride-induced vascular contraction than thromboxane $A_2$ or phorbol ester-induced contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, eupatilin significantly inhibited fluoride-induced increases in pMYPT1 levels. On the other hand, it didn't significantly inhibit phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the primarily inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1. This study provides evidence regarding the mechanism underlying the relaxation effect of eupatilin on agonist-induced vascular contraction regardless of endothelial function.

• Molecules and Cells
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• v.38 no.7
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• pp.597-603
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• 2015

Biosynthesis of the phytohormone ethylene is under tight regulation to satisfy the need for appropriate levels of ethylene in plants in response to exogenous and endogenous stimuli. The enzyme 1-aminocyclopropane-1-carboxylic acid synthase (ACS), which catalyzes the rate-limiting step of ethylene biosynthesis, plays a central role to regulate ethylene production through changes in ACS gene expression levels and the activity of the enzyme. Together with molecular genetic studies suggesting the roles of post-translational modification of the ACS, newly emerging evidence strongly suggests that the regulation of ACS protein stability is an alternative mechanism that controls ethylene production, in addition to the transcriptional regulation of ACS genes. In this review, recent new insight into the regulation of ACS protein turnover is highlighted, with a special focus on the roles of phosphorylation, ubiquitination, and novel components that regulate the turnover of ACS proteins. The prospect of cross-talk between ethylene biosynthesis and other signaling pathways to control turnover of the ACS protein is also considered.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.511-519
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• 2007

It is known that phytoplankton biomass or turbidity are lower in waters with submerged macrophytes than those without submerged plants at a given nutrient level. We hypothesize that presence of submerged macrophytes would lower phytoplankton biomass below levels expected by total phosphorus levels through various mechanisms and that phytoplankton biomass would decrease more as the biomass increase of the submerged macrophytes. To find submerged macrophytes effectively lowering phytoplankton growth, we conducted spatial field surveys at 21 water bodies and a temporal monitoring at Seung-un 1 Reservoir, Anmyyeondo Island. We measured chlorophyll ${\alpha}$ concentrations and total phosphorus (TP) concentrations from waters in patches of submerged macrophytes with measurements of submerged plant biomass. Majority of our sites with submerged macrophytes showed much less chlorophyll a concentrations than the predicted ones from literature. Among submerged macrophytes studied, Myriophyllum spicatum and Hydrilla verticillata showed patterns of lowering chlorophyll ${\alpha}/TP$ ratios with increase of their biomass in both spatial and temporal surveys.

• Asia pacific journal of information systems
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• v.15 no.3
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• pp.41-64
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• 2005

The effects of information quality and the importance of information have been reported in the information Systems(IS) literature. However, little has been learned about the impact of data quality(DQ) on decision performance. Recognizing with this problem, this study explores the effects of contextual DQ on decision performance. To examine them, a laboratory experiment was conducted. Based on two levels of contextual DQ and two levels of task complexity, this study had a $2{\times}2$ factorial design. The dependent variables used to measure the outcomes of decision performance were problem-solving accuracy and time. The results demonstrated that the effects of contextual DQ on decision performance were significant. The findings suggest that decision makers can expect to improve their decision performance by enhancing contextual DQ. This research not only extends a body of research examining the effects of factors that can be tied to human decision-making performance, but also provides empirical evidence to validate and extend DeLone and McLean's IS success model.

• YAKHAK HOEJI
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• v.57 no.5
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• pp.376-381
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• 2013

The present study was undertaken to investigate the influence of curcumin on vascular smooth muscle contractility and to determine the mechanism involved. We hypothesized that curcumin, the primary ingredient of Curcuma longa, plays a role in vascular relaxation through inhibition of Rho-kinase in rat aortae. Denuded arterial rings from male Sprague-Dawley rats were used and isometric tensions were recorded using a computerized data acquisition system. Interestingly, curcumin inhibited fluoride-induced contraction but didn't inhibit phorbol ester-induced contraction suggesting that additional pathways different from endothelial nitric oxide synthesis might be involved in the vasorelaxation. Furthermore, curcumin significantly inhibited fluoride-induced increases in pMYPT1 levels. On the other hand, it didn't significantly inhibit phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving inhibition of fluoride-induced MYPT1 phosphorylation. This study provides evidence that curcumin induces vascular relaxation through inhibition of Rho-kinase in rat aortae.

• Asia pacific journal of information systems
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• v.13 no.2
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• pp.1-21
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• 2003

Although the internet community(IC) has been recognized as an increasingly important for better understanding and relationships with customers, few evidence has been accumulated what factors influence IC success. This study posits the characteristics and individual characteristics as key determinants of IC success, and related hypotheses were tested using 230 data. Using user loyalty as a surrogate of IC success, this study found that the three key characteristics of IC-focus, interactivity, and cohesion levels-significantly influence the community user's loyalty. In addition, individual characteristics including personal value propositions(e.g, challenge/ambitious value, economic/rational value) and absorption tendency(e.g., flow level) affect their loyalty levels. This study also found that the determinents of IC user's loyalty defer with different types of community such as entertainment, relationships, and information/opinion sharing communities. These findings are hopefully helpful for the successful and contingent management of IC buildings and operations.

• Applied Microscopy
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• v.21 no.1
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• pp.27-45
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• 1991

To study the effects of dietry methionine level on lipid peroxidation of rats, rats were fed vitamin E, selenium and methionine - deficient diet or the same diet supplemented with various levels(0.3%, 0.6%, 0.9%) of methionine for 6 weeks. The biochemincal and mophological changes in the rat liver were investigated. Lipid peroxide levels in plasma and hepatic mitochondrial fraction of MF rats were more increased than those of control rats. However, supplementation with 0.6% methionine modified this increment. Catalase activity was decreased in hepatic mitochondrial fraction from rats fed MF diet. Methionine supplementation did not induce this enzyme. The ultrastructural evidence for lipid peroxidation was found in plasma membranes facing sinusoids. The most striking changes in including disruption and loss of microvilli and development of numerous lipid droplets occurred in rats fed MF diet. These changes were not effectively prevented by the same diet supplemented with 0.3% or 0.9% methionine, but supplementation with 0.6% methionine modulated more or less the changes.

• The Korean Journal of Zoology
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• v.38 no.1
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• pp.66-73
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• 1995

Putative gamma aminobu%sic acid (GABA)-ersic elements in the basilar pontine nuclei were examined in the dos using an antiserum against GABA-glutaraldehvde-protein conjusBtes and the peroxidase-antiperoxidase method. GABA-immunoreactive neuronal somata in the basilar Pons exhibited various morphology with the majority being spindle-shaped or multipolar, while some were spheroidal. The size of GABA-orgic neuronal somata was relatively small (approximately $10-20\mum)$ in diameter. GABA-immunoreactive neurons were scattered throughout the pontine nuclei, but the midline region of the medial nucleus at the rostral pons, the lateral nucleus at mid-pontine levels, and the ventral nucleus at the caudal pons exhibited a relatively greater concentration of cell bodies. A sparse number of GABA-ergic neurons were observed within the cerebral peduncle and along the ventral borders of the basilar pons adjacent to the middle cerebellar peduncle at the rostrocaudal levels of the pontine nuclei. These obsenrations provide anatomic evidence of how this inhibitory neural element performs its function in the cortico-prontocerbellar circuitry.

• KDI Journal of Economic Policy
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• v.38 no.4
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• pp.77-94
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• 2016

This paper examines the empirical magnitude of local human capital spillovers in Korea during the 1980s and mid-1990s. Local human capital spillovers exists if plants in regions with a higher level of human capital can produce more given their own amount of input (Moretti 2004c). In particular, this paper explores an educational reform in South Korea which exogenously induced a large amount of variation in regional human capital levels. Using annually collected plant level data, I explore the effect of changes in the regional human capital levels induced by this reform on plant productivity in Korea. My results suggest that this effect is limited. I find a positive correlation between a regional level of human capital and plant productivity. However, after further addressing endogeneity using an instrumental variable, the effect of the overall regional human capital level on productivity decreases and becomes statistically insignificant.