• Journal of Electrical Engineering and Technology
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• v.7 no.1
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• pp.1-8
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• 2012

The current paper presents a novel control strategy of a three-phase, four-wire Unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, a zero-crossing detector and sample-and-hold circuits are used. For the control of shunt APF, a simple scheme based on the real component of fundamental load current (I $Cos{\Phi}$) with reduced numbers of current sensors is applied. The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. In this proposed UPQC control scheme, the current/voltage control is applied to the fundamental supply currents/voltages instead of fast-changing APF currents/voltages, thus reducing the computational delay and the required sensors. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained.

• Molecules and Cells
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• v.38 no.2
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• pp.145-150
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• 2015

Continuous intra- and extracellular stresses induce disorder of $Ca^{2+}$ homeostasis and accumulation of unfolded protein in the endoplasmic reticulum (ER), which results in ER stress. Severe long-term ER stress triggers apoptosis signaling pathways, resulting in cell death. Neural epidermal growth factor-like like protein 2 (NELL2) has been reported to be important in protection of cells from cell death-inducing environments. In this study, we investigated the cytoprotective effect of NELL2 in the context of ER stress induced by thapsigargin, a strong ER stress inducer, in Cos7 cells. Overexpression of NELL2 prevented ER stress-mediated apoptosis by decreasing expression of ER stress-induced C/EBP homologous protein (CHOP) and increasing ER chaperones. In this context, expression of anti-apoptotic Bcl-xL was increased by NELL2, whereas NELL2 decreased expression of pro-apoptotic proteins, such as cleaved caspases 3 and 7. This anti-apoptotic effect of NELL2 is likely mediated by extracellular signal-regulated kinase (ERK) signaling, because its inhibitor, U0126, inhibited effects of NELL2 on the expression of anti- and pro-apoptotic proteins and on the protection from ER stress-induced cell death.

• Korean Journal of Plant Resources
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• v.29 no.6
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• pp.679-689
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• 2016

Lettuce is an important annual leafy vegetable and bitterness is its potent flavor character. Lettuce germplasm differ their phenotypic characters and sesquiterpene lactones (SLs) contents which are important for consumer's acceptance. This study was carried out to evaluate the phenotypic characters and SLs contents in one hundred lettuce germplasm in Jeonju, Korea. Twenty-three agro-morphological (16 qualitative and 7 quantitative) traits and two SLs (lactucin and lactucopicrin) contents were studied in these germplasm. Germplasm exhibited the variation in qualitative and quantitative characters. Average plant weight was 423.9 g with a range from 116.0 to 905.0 g. Lactucin content was varied from 19.7 (IT 294226) to $194.4{\mu}g/g$ (IT 294298) with an average concentration of $84.7{\mu}g/g$. Lactucopicrin ranged from 82.5 (IT 300134) to $2228.6{\mu}g/g$ (IT 294210) with an average concentration of $586.3{\mu}g/g$. Total SLs content was ranged from 120.1 (IT 300134) to 2286.6 (IT 294210)${\mu}g/g$ with the average concentration of $671.0{\mu}g/g$. Significant ($p{\leq}0.05$) differences were found between crisp head and butter head germplasm for lactucin, lactucopicrin and total SLs content. Crisp head germplasm revealed the highest average lactucin ($112.9{\mu}g/g$), lactucopicrin ($734.8{\mu}g/g$) and total SLs content ($847.7{\mu}g/g$). Crisp head and leafy type germplasm exhibited more total SLs content (847.7 and $744.7{\mu}g/g$, respectively) than cos ($524.9{\mu}g/g$) and butter head type ($519.4{\mu}g/g$). Principal component analyses of the quantitative traits indicated that the first principal component axis accounted more than 91% of the total variation. This study revealed the ample genetic variation in the agro-morphological traits and SLs contents to support the selection for improved lettuce varieties.

• Clean Technology
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• v.7 no.3
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• pp.187-194
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• 2001

The desulfurization process which belongs to the gas refining part is the unit process that eliminates $H_2S$ and COS in the coal gas formed by the coal gasification part in the integrated gasification combined cycle(IGCC). In this study, natural manganese ores were selected as the raw material of the desulfurization sorbent due to economical efficiency. Initial rates for the reactions between $H_2S$ and desulfurization sorbent using natural manganese ores were determined in a temperature range of $400{\sim}800^{\circ}C$ using a thermobalance reactor. All reactions were first order with respect to $H_2S$ and were in accord with the Arrhenius equations. When sulfidation reaction was controlled by diffusion, the temperature dependence of the effective diffusivity was given by the Arrhenius equation. Activation energies and frequency factors were obtained from the product layer diffusion coefficient of various sorbents by plotting as Arrhenius equation form.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.56-60
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• 2005

We studied fire properties of MOF(Metering Out Fit) insulation cover and field condition of 22.9kV power receiving system. $49.5\%$ of formal equipments were installed indoors, whereas $40.8\%$ of informal equipments were installed as H-type. Insulation treatment was not done at a $22.4\%$ ratio of main line($27.7\%$ of transformer, $70.2\%$ of COS, $10.4\%$ of MOF). Fire pattern analysis showed that the fire started at the secondary part of OC wire. In the result of DTA(Differential Thermal Analysis), normal cover showed exothermic reactions at $310^{\circ}C,\;399^{\circ}C\;and\;510^{\circ}C$ (endothermic reactions at $382^{\circ}C$). Whereas damaged cover showed exothermic reactions at $412^{\circ}C$(endothermic reactions at $389^{\circ}C$). In the result of TGA(Thermo Gravimetric Analysis), the thermal weight change of normal cover was similar compared to damaged cover. In the result of FT-IR analysis, normal cover showed absorption peaks at $3,024cm^{-l},\;2,921cm^{-l},\;1,600cm^{-1},\;1,492cm^{-1},\;1,451cm^{-1},\;1,154cm^{-l},\;1,027cm^{-1},\;906cm^{-1}$. Whereas, in case of tracked cover, the absorption peaks that were shown in normal cover disappeared and different absorption peak was shown at $966cm^{-1}$.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.181-181
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• 1996

The (Na, K) ATPase is a membrane ion transporting ATPase composed of an ${\alpha}$ catalytic subunit and a ${\beta}$ glycoprotein subunit. The topology of the rat ${\alpha}$1 and ${\beta}$1 subunits has been studied by insertion of epitope(s) : at the NH2-terminus and COOH-terminus and between Glu117 and Glul18, Lys828 and Arg829, Gln900 and Trp901, and Va1939 and Phe940 of the ${\alpha}$ subunit; and at the NH2-terminus and COOH-terminus and between Glu228 and Tyr229 of the ${\beta}$ subunit. The epitope-tagged ${\alpha}$l, constructs were expressed in HeLa cells to select for stable cell lines expressing a functional (Na, K)ATPase. All constructs, except for the one tagged between Gln900 and Trp901, resulted in ouabain-resistant colonies indicating that modified proteins retained functional integrity. The epitope-tagged ${\beta}$ constructs were transiently expressed in Cos-7 cells. The orientation of the epitopes with respect to the cell membrane was revealed by indirect immunofluorescence performed on permeabilized and non-permeabilized cells expressing the (Na, K)ATPase chains. The results indicate that the ${\alpha}$ subunit has 4 transmembrane segments in the COOH terminal membrane bound domain between residues 760 and 938, and that both the NH2-terminus and the COOH-terminus are in the cytosol; it was not determined whether there are more transmembrane segments between residue 938 and the COOH-terminus. The ${\beta}$ subunit has only one transmembrane spanning region with the NH2-terminus in the cytosol and the COOH-terminus on the extracytoplasmic surface of the plasma membrane.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1031-1037
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• 2004

The interaction of chemoattractant receptors and $G{\alpha}_{16}$ was studied to provide the molecular basis to elucidate the interaction of chemoattractant receptors with $G{\alpha}_{16}$ subunit, thereby possibly contributing to finding novel targets for designing new type of G protein antagonists with anti-inflammatory effects. Experiments were performed to characterize the $G{\alpha}_{16}$ subunit domains responsible for efficient coupling to chemoattractant receptors. Thus, a series of chimeric $G{\alpha}_{11}G{\alpha}_{16}$ and $G{\alpha}_{16}G{\alpha}_{11}$ cDNA constructs were expressed, and the ability of chimeric proteins to mediate C5a, IL-8, and fMLP-induced release of inositol phosphate in transfected Cos-7 cells was tested. The results showed that short stretches of residues 154 to residue 167 and from residue 174 to residue 195 of $G{\alpha}_{16}$ contribute to efficient coupling to the C5a receptor. On the other hand, a stretch of amino acid residues 220-240 of $G{\alpha}_{16}$ that is necessary for interacting with C5a receptor did not play any role in the interaction with IL-8 receptor. However, a stretch from residue 155 to residue 195 of $G{\alpha}_{16}$ was found to be crucial for efficient coupling to IL-8 receptor in concert with C-terminal 30 amino acid residues of this ${\alpha}$ subunit. Coupling profiles of a variety of chimeras, composed of $G{\alpha}_{11}G{\alpha}_{16}$ to fMLP receptor indicate that the C-terminal 30 amino acids are most critical for the coupling of $G{\alpha}_{16}$ to fMLP receptor. Taken together, $G{\alpha}_{16}$ subunit recruits multiple and distinctive coupling regions, depending on the type of receptors, to interact.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1283-1288
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• 2000

Objectives : The subcellular locations of Bad, Bid, Bax and Bcl-XL change during apoptosis and this change is important for the regulation of cell death. The purpose this study was to elucidate binding of Bad with Bcl-XL in vivo Methods : We mads Bad with Green Fluorescent Protein(GFP) using PCR method. We transfected and overexpressed GFP-Bad with or without Bcl-XL cotransfection in living COS-7 cell. Results : Bad and Bcl- XL bind one another in healthy living cells and this association controled mitochondrial docking. In the absence of Bad-XL, Bad was mainly cytosolic and partially bound to mitochondria. Upon coexpression of Bad and Bcl-XL, most of Bad translocated to mitochondria. These should suggest that Bad binds to the mitochondrial and cytoplasmic forms of Bcl-XL and Bad bound to cytoplasmic Bcl-XL translocates to mitochondria. These in vivo findings confirm that Bad make a complexes with Bcl- XL and cause mitochondrial translocation of Bad-Bcl-XL complex.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.211-216
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• 2008

TREK (TWIK-RElated $K^+$ channels) and TRAAK (TWIK-Related Arachidonic acid Activated $K^+$ channels) were expressed in COS-7 cells, and the channel activities were recorded from inside-out membrane patches using holding potential of - 40 mV in symmetrical 150 mM $K^+$ solution. Intracellular application of an oxidizing agent, 5,5'-dithio-bis (2-nitrobenzoic acid) (DTNB), markedly decreased the activity of the TREK2, and the activity was partially reversed by the reducing agent, dithiothreitol (DTT). In order to examine the possibility that the target sites for the oxidizing agents might be located in the C-terminus of TREK2, two chimeras were constructed: TREK2 (1-383)/TASK3C and TREK2 (1-353)/TASK3C. The channel activity in the TREK2 (1-383)/TASK3C chimera was still inhibited by DTNB, but not in the TREK2 (1-353)/TASK3C chimera. These results indicate that TREK2 is inhibited by oxidation, and that the target site for oxidation is located between the amino acid residues 353 and 383 in the C-terminus of the TREK2 protein.

• Biomedical Science Letters
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• v.12 no.4
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• pp.419-425
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• 2006

Phospholipase $C-{\gamma}1\;(PLC-{\gamma}1)$ is an important signaling molecule for cell proliferation and differentiation. $PLC-{\gamma}1$ contains two pleckstrin homology (PH) domains, which are responsible for protein-protein interaction and protein-lipid interaction. $PLC-{\gamma}1$ also has two Src homology (SH)2 domains and a SH3 domain, which are responsible for protein- protein interaction. To identity proteins that specifically binds to PH domain of $PLC-{\gamma}1$, we prepared and incubated the glutathione S-transferase(GST)-fused PH domains of $PLC-{\gamma}1$ with COS7 cell lysate. We found that 90 kDa protein specifically binds to PH domain of $PLC-{\gamma}1$. By matrix-assisted laser desorption ionization time of flight-mass spectrometry, the 90 kDa protein revealed to be heat shock protein (Hsp) $90{\beta}$. Hsp $90{\beta}$ is a molecular chaperone that stabilizes and facilitates the folding of proteins that are involved in cell signaling, including receptors for steroids hormones and a variety of protein kinases. To know whether Hsp $90{\beta}$ affects on $PLC-{\gamma}1$ activity, we performed $PIP_2$ hydrolyzing activity of $PLC-{\gamma}1$ in the presence of purified Hsp $90{\beta}$ in vitro. Our results show that the Hsp $90{\beta}$ dose-dependently inhibits the enzymatic activity of $PLC-{\gamma}1$ and further suggest that Hsp $90{\beta}$ regulates cell growth and differentiation via regulation of $PLC-{\gamma}1$ activity.