• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.353.2-353.2
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• 2016

We studied electrochemical detection of Botulinum neurotoxin, Vaccinia virus, and Streptococcus Pneumoniae based on nanogap device. Target bio substances were employed as representative targets of protein, virus, and bacteria, respectively. Redox current generated by ferri/ferrocyanide as an electroactive probe was enhanced according to gap distance which was controlled by surface-catalyzed chemical deposition. We found that enhanced electrochemical signal leads more sensitive signal changes according to selective interaction of target and its complementary elements on the electrode or gap area. In case of Botulinum neurotoxin, the redox signal showed a time-dependent increase due to cleavage of the immobilized peptide which blocked redox cycling. Redox cycling was also hindered by Vaccinia virus and Streptococcus Pneumoniae which were selectively immobilized in the gap area.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.269-278
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• 2005

To justify the economic impacts of the internet access management is a purpose of this paper. Previous researches on economic justification were reviewed and the internet access management system. sniffer, and firewall were implemented to monitor real-time sessions and to record blocked attempts. This paper suggests the impact factors and measurement methods to justify the economic values of the internet access management system. Finally, this paper Proves that the overall impacts of the internet access management system have a Positive value because filtering mechanisms cause users to lose a small number of URLs including useful information and to diminish refreshment but save users from various risk points and enhance labor productivity.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2004.11a
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• pp.53-60
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• 2004

The pro-apoptotic effect of phenethyl isothiocyanate (PEITC) and the role of glutathione (GSH) in sulforaphane (SFN)-induced antioxidant response element-dependent gene expression were investigated. The caspase-3 and caspase-9 activities were stimulated by PEITC. The release of cytochrome c was time- and dose- dependent. SP600125 suppressed apoptosis induced by PEITC. Similarly, this JNK inhibitor attenuated both cytochrome c release and caspase-3 activation induced by PEITC. SFN is converted to the glutathione conjugate by glutathione S-transferases (GSTs). It was accumulated in mammalian cells by up to several hundred-fold over the extracellular concentration, by conjugation with intracellular GSH. The induction of ARE by SFN was 8.6-fold higher than by SFN-NAC. The decrease in ARE expression at higher concentrations of SFN and SFN-NAC was correlated with the accelerated apoptotic cell death, with a dose-dependent activation of caspase 3 activity by SFN. Upon addition of extracellular GSH within 6 hr of treatment with SFN, the effect on ARE expression was blocked almost completely.

• Biomolecules & Therapeutics
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• v.18 no.3
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• pp.262-270
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• 2010

CD95 receptor is a member of tumor necrosis factor receptor family that mediates apoptosis in many cell types when bound by CD95 ligand or cross-linked by agonistic anti-CD95 antibodies. To determine the role of neutral sphingomyelinase (nSMase) on CD95-mediatd apoptosis, human Jurkat T lymphocytes were exposed to recombinant human CD95 ligand. Treatment with CD95 ligand induced cell death in a concentration and time-dependent manner. CD95-induced cell death was suppressed by inhibitors of SMase such as AY9944 or desipramine. Transfection with human nSMase1 siRNA plasmid into CD95 ligand-treated cells significantly prevented CD95-mediated cell death. CD95-mediated elevation of intracellular ceramide level detected by FACS analysis with anti-ceramide antibody was also decreased by nSMase1 siRNA. Knock-down of nSMase1 expression also blocked cytochrome c release into cytosol and caspase-3 cleavage in CD95-treated cells. Taken together, these results suggest that nSMase1 may play an important role in CD95-mediated apoptotic cell death in Jurkat T cells.

• Journal of Nutrition and Health
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• v.28 no.9
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• pp.825-833
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• 1995

This study was performed to investigate the influence of dietary fiber, which from whole food on the serum lipid level and bowel function in rats. The fiber sources of experimental diets were prepared by drying and milling of small water dropwort(WD), mugwort(MW), butterbur(BB) and apple(AP). Each fiber sources was mixed at the 15% level of the diet. The level of dietary fiber in WD, MW, BB diets was similar but that in AP diet was slightly low. Male rats of Sprague-Dawley strain were blocked into 5 groups ; WD, MW, BB, AP, FF(fiber free). The animals were fed ad libitum each of experimental diets for 37 days. Food intake of AP and FF groups were than other groups, FF group was lower than other grous in food efficiency ratio. MW group showed highest level in fecal weight and fecal water content and group has the longest transit time compare to other groups. Serum triglyceride level was not significantly different among groups. BB group showed the lowest level in the serum total cholesterol. WD and MW groups showed slightly higher level in the serum HDL cholesterol than other groups. Mucosa weight was not significantly different among groups. The activity of maltase in mucosa of small intestine was highest in FF groups. Absorption rates of calcium were not significantly different among groups. Absorption rate of magnesium was higher in FF group compare to others. And, absorption rates of phosphorus in MW and FF groups were slightly lower than other groups.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.104-110
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• 2014

The Han River is the only waterway in Korea where estuary is not blocked by dykes so that tidal water is flowing in and out through the tidal reach. The extreme tidal range in the Yellow Sea causes an intense flood current, stretching over horizontal extents of tens of kilometers into the rivers. To elucidate the flow reversal by discharge conditions and transient tidal level in the Han river, numerical simulations were conducted under 7 boundary conditions for two days with 10 minute time step. As the flow conditions changed from low discharge and high tidal difference to high discharge and low tidal difference, the flow reversals became weaker and the velocity of forward flow direction became higher due to the increased flow momentums and decreased tidal differences. In the case of normal flow, the maximum reverse velocity was 0.4 m/s, which was equivalent to the maximum forward velocity. In addition, the pattern of the development and decay of forward and reverse flow was presented.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.387-394
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• 2017

This paper develops a pump system for patient with chronic pain or cancer. The pump module is consists of two micro-valve and membrane. The micro-valve is operated by a solenoid. With two solenoid valves which are connected via a drug transport line, the inlet and outlet are completely blocked. A silicon rubber membrane located between the two valves makes the flow-rate constant without any backflow. This pump module can control the flow-rate of drugs by controlling the time that the valves are opened and closed. The reservoir consists of a drug chamber and a gas chamber. As the gas chamber encloses the drug chamber, propellant gas which is injected into the gas chamber pressurizes the drug chamber regardless of volume of the drug chamber. To design the pump module, analysis a constant efficiency test, and accuracy test for the pump module were conducted.

• Development and Reproduction
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• v.14 no.1
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• pp.27-34
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• 2010

A fertilized oocyte can get the competence for implantation through cleavage and stage-specific gene expression. These are under the control of autonomous and exogenous regulators including physiological culture condition. Endogenous and exogenous growth factors are considered as critical regulators of cleaving embryos during travel the oviduct and uterus. In this study, an effort was made to evaluate comprehensively the quality of embryos for implantation, grown in media enriched with EGF and PAF. The study evaluated developmental rates on given time, blastulation and hatching rates, and adhesion rates. Developmental rates of blastocyst to the hatching stage were significantly high in PAF treated group compared to the control in a dose-dependent manner but not in EGF group. Implantation rates were significantly high both PAF and EGF in a dose-dependent manner. H7, a PKC inhibitor, blocked the process of hatching of the blastocysts but combined treatment of EGF and PAF enhanced the hatching and implantation of blastocsyts. Based on these results it is suggested that EGF and PAF support acquirement of implantation competence at blastocyst stage through a PKC pathway.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.291-299
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• 1995

Lateral giant (LG)-mediated escape response of crayfish is sensitized by natural traumatic events. Such sensitization has previously been shown to be associated with increased transmission between primary afferents and sensory interneurons at the cholinergic synapse of LG escape reflex circuit. In the present study, it was firstly investigated as to whether transmission is also altered at other synapses of the LG-escape reflex circuit by traumatic shock-induced sensitization. Evidence that traumatic shock also directly affects the excitability of lateral giants is now provided by the finding that traumatic shock produces a significant reduction of the time needed for LG to recruit its contralateral homologue, which is defined as commissural delay. Octopamine, a naturally occurring neuromodulator in the crayfish nerve cord, has also been shown to enhance transmission at the cholinergic synapse between primary afferents and sensory interneurons, and has been conjectured to mediate sensitization. Like traumatic shock, $octopamine\;(10^{-5}-5{\times}10^{-4}\;M)$ also enhanced the efficacy of commissural transmission between lateral giants, as indicated by a significant reduction of commissural delay. This effect was blocked by an octopamine antagonist phentolamine, suggesting a specific action of octopamine on the octopamine receptor present on LGs. These observations suggest that both traumatic shocks and octopamine may cause a rather broad alteration in the excitability of the crayfish nervous system that contributes to the sensitization of the LG escape response.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.107-115
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• 1997

We studied the effects of bile acids on the induction ofapoptosis in HepG2 human hepatocellular carcinoma cells. Treatment with either ursodeoxycholic acid (UDCA) or lithocholic acid (LCA) resulted in a dose- and time-dependent decrease in cell viability assessed by MTT assay. Both UDCA and LCA also induced genomic DNA fragmentation, a hallmark of apoptosis, indicating that the mechanism by which these bile acids induce cell death was through apoptosis. Cycloheximide, a protein synthesis inhibitor, blocked the apoptosis induced by these bile acids, implying that new protein synthesis may be required for the apoptosis. Intracellular $Ca^{2+}$ release blockers (dantrolene and 3,4,5-trimethoxybenzoic acid-8-(diethylamino)octyl ester) inhibited decreased cell viability and DNA fragmentation induced by these bile acids. Treatment of HepG2 cells with calcium ionophore A23l87 induced DNA fragmentation. These results suggest that UDCA and LCA induce apoptosis in the HepG2 cells and that the activation of intracellular $Ca^{2+}$ signals may play an important role in the apoptosis induced by these bile acids.