• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.639-642
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• 2013

In this paper, proposed NED(nuclear event detectors) for detection of a transient radiation. Nuclear event detector was blocked of power temporary for defence of critical damage at a electric device when a induced transient radiation. Conventional NED consist of BJT, resistors and capacitors. The NED supply voltage of 5V and MCM(Multi Chip Module) structures. The proposed NED were designed for low supply voltage using 0.18um CMOS process. The response time of proposed NED was 34.8ns. In addition, pulse radiation experiments using a electron beam accelerator, the output signal has occurred.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.4
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• pp.187-191
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• 2002

Tamoxifen, an antiestrogen, has previously been shown to induce apoptosis in HepG2 human hepatoblastoma cells through activation of the pathways independent of estrogen receptors, i.e., intracellular $Ca^{2+}$ increase and generation of reactive oxygen species (ROS). However, the mechanism of tamoxifen to link increased intracellular $Ca^{2+}$ to ROS generation is currently unknown. Thus, in this study we investigated the possible involvement of calmodulin, a $Ca^{2+}$ activated protein, and $Ca^{2+}$/calmodulin-dependent protein kinase II in the above tamoxifen-induced events. Treatment with calmodulin antagonists (calmidazolium and trifluoroperazine) or specific inhibitors of $Ca^{2+}$/calmodulin-dependent protein kinase II (KN-93 and KN-62) inhibited the tamoxifen-induced apoptosis in a dose-dependent manner. In addition, these agents blocked the tamoxifen-induced ROS generation in a concentration-dependent fashion, which was completely suppressed by intracellular $Ca^{2+}$ chelation. These results demonstrate for the first time that, despite of its well-known direct calmodulin-inhibitory activity, tamoxifen may generate ROS and induce apoptosis through indirect activation of calmodulin and $Ca^{2+}$/calmodulin-dependent protein kinase II in HepG2 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.2
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• pp.193-201
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• 2018

Connective tissue growth factor (CTGF) is a novel fibrotic mediator, which is considered to mediate fibrosis through extracellular matrix (ECM) synthesis in diabetic cardiovascular complications. Statins have significant immunomodulatory effects and reduce vascular injury. We therefore examined whether fluvastatin has anti-fibrotic effects in vascular smooth muscle cells (VSMCs) and elucidated its putative transduction signals. We show that advanced glycation end products (AGEs) stimulated CTGF mRNA and protein expression in a time-dependent manner. AGE-induced CTGF expression was mediated via ERK1/2, JNK, and Egr-1 pathways, but not p38; consequently, cell proliferation and migration and ECM accumulation were regulated by CTGF signaling pathway. AGE-stimulated VSMC proliferation, migration, and ECM accumulation were blocked by fluvastatin. However, the inhibitory effect of fluvastatin was restored by administration of CTGF recombinant protein. AGE-induced VSMC proliferation was dependent on cell cycle arrest, thereby increasing G1/G0 phase. Fluvastatin repressed cell cycle regulatory genes cyclin D1 and Cdk4 and augmented cyclin-dependent kinase inhibitors p27 and p21 in AGE-induced VSMCs. Taken together, fluvastatin suppressed AGE-induced VSMC proliferation, migration, and ECM accumulation by targeting CTGF signaling mechanism. These findings might be evidence for CTGF as a potential therapeutic target in diabetic vasculature complication.

• Nutrition Research and Practice
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• v.3 no.3
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• pp.192-199
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• 2009

Cadmium intoxication has been associated with the dysregulation of iron homeostasis. In the present study, we investigated the effect of cadmium on the expression of ferroportin 1 (FPN1), an important iron transporter protein that is involved in iron release from macrophages. When we incubated cadmium with J774 mouse macrophage cells, FPN1 mRNA levels were significantly increased in a dose- and time-dependent manner. Furthermore, the cadmium-induced FPN1 mRNA expression was associated with increased levels of FPN1 protein. On the other hand, cadmium-mediated FPN1 mRNA induction in J774 cells was completely blocked when cells were co-treated with a transcription inhibitor, acitomycin D. Also, cadmium directly stimulated the activity of the FPN1-promoter driven luciferase reporter, suggesting that the cadmium up-regulates FPN1 gene expression in a transcription-dependent manner. Finally, cadmium exposure to J774 macrophages increased intracellular reactive oxygen species (ROS) levels by ${\sim}2$-fold, compared to untreated controls. When J774 cells were co-treated with antioxidant N-acetylcystein, the cadmium-induced FPN1 mRNA induction was significantly attenuated. In summary, the results of this study clearly demonstrated that cadmium increased FPN1 expression in macrophages through a mechanism that involves ROS production, and suggests another important interaction between iron and cadmium metabolism.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.189-193
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• 1993

Exposure of dissociated cultures from fetal rat brainstem to glutamate for upto 6 h decreased cellular contents of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in a concentration- and time-dependent manner. In addition, glutamate induced lactate dehydrogenase leakage. Tetrodotoxin did not block the effects induced by glutamate. MK-801 $(1{\mu}M)$, an N-methyl-D-aspartate (NMDA) channel blocker, but not 6-cyano-2,3-dihydroxy-7-nitro-quinoxazoline $(CNQX;\;3{\mu}M)$, a non-NMDA receptor antagonist, blocked glutamate-induced effects, indicating that these glutamate-induced responses are mediated through NMDA receptors.

• Archives of Pharmacal Research
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• v.27 no.11
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• pp.1147-1153
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• 2004

Bladder cancer is a common cancer with high risk of recurrence and mortality. Intravesicle chemotherapy after trans-urethral resection is required to prevent tumor recurrence and progression. It has been known that antioxidants enhance the antitumor effect of bacillus Calmette-Guerin (BCG), the most effective intravesical bladder cancer treatment. Capsaicin, the major pungent ingredient in genus Capsicum, has recently been tried as an intravesical drug for overactive bladder and it has also been shown to induce apoptotic cell death in many cancer cells. In this study, we investigated the apoptosis-inducing effect and alterations in the cellular redox state of capsaicin in MBT-2 murine bladder tumor cells. Capsaicin induced apoptotic MBT-2 cell death in a time- and dose-dependent manner. The capsaicin-induced apoptosis was blocked by the pretreatment with Z-VAD-fmk, a broad-range caspase inhibitor, or Ac-DEVD-CHO, a caspase-3 inhibitor. In addition to the caspase-3 activation, capsaicin also induced cytochrome c release and decrease in Bcl-2 protein expression with no changes in the level of Bax. Furthermore, capsaicin at the concentration of inducing apoptosis also markedly reduced the level of reactive oxygen species and lipid peroxidation, implying that capsaicin may enhance the antitumor effect of BCG in bladder cancer treatment. These results further suggest that capsaicin may be a valuable intravesical chemotherapeutic agent for bladder cancers.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.147-152
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• 2018

A polarizing spectacle lens having a perfect blocking of ultraviolet light and a partial blocking of blue light and having photochromic properties has been developed. It is a functional spectacle lens which can be used as a spectacle lens in the daytime, which plays a role of sunglass in a space with strong ultraviolet rays, dramatically reducing glare caused by late-night driving or reflected light. Photochromism was recovered in 0.5 second dark reaction and 3 seconds recovery time. The polarization function was about 95%. Ultraviolet rays were completely blocked and blue light was reduced by about 30%. A lens that combines photochromic and UV blocking and polarization functions is the first attempt at investigating the domestic market.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.102-107
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• 2012

Halogen lamp was applied to fabricate the selective emitter crystalline silicon solar cell. In selective emitter structure, the recombination of minority carriers is reduced with heavily doped emitter under metal grid, consequently improving the conversion efficiency. Laser selective emitter process which is recently used the most generally induces the damage on the silicon surface. However the lamp has enough heat to form heavily doped emitter layer by diffusing phosphorus from PSG without surface damage. In this work, we have studied to find the design and the suitable condition for halogen lamp such as power, time, temperature and figured out the possibility to fabricate the selective emitter silicon solar cell by lamp heating. The sheet resistance with $100{\Omega}/{\Box}$ was lower to $50{\Omega}/{\Box}$ after halogen lamp treatment. Heat transfer to lightly doped emitter region was blocked by using the shadow mask.

• Journal of Environmental Science International
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• v.15 no.11
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• pp.1035-1043
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• 2006

Large scale of fish kills by red tides has been occurred every year in coastal water fisheries of Korea. To suppress red tide spreading out over the south coastal water of the Korean Peninsula large amount of loess has been applied every year because loess is known to be effective in removing red tide organisms. Effects of loess application in ecosystem of underwater near sea shore were investigated with some physical characteristics of loess. Loess used for the red tide reduction consisted of very fine particles, of which size was mostly less than 0.1 mm. Particles of loess blocked light penetration, which is essential for the underwater ecosystem. Loess also pushed pH down by the hydrolysis activities of aluminium and iron It was found that underwater ecosystems where loess was applied near sea shore were devastated. Sea plants such as sea weeds were gone leaving only their roots. Clams and snails were dead under the loess dust blanket. And fishes were not found at all where loess has been sprayed lot long time. It was found that even if loess has some capacity to reduce red tide temporarily, loess application should be slopped to protect underwater ecosystems.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.248-257
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• 2005

In this paper, we develop design procedures for carrier tracking loop for orthogonal frequency division multiplexing (OFDM) systems or other systems of blocked data. In such communication systems, phase error measurements are made infrequent enough to invalidate the traditional loop design methodology which is based on analog loop design. We analyze the degradation in the OFDM schemes caused by the tracking loop and show how the performance is dependent on the rms phase error, where we distinguished between the effect of the variance in the average phase over the symbol and the effect of the phase change over the symbol. We derive the optimal tracking loop including optional delay in the loop caused by processing time. Our solution is general and includes arbitrary phase noise apd additive noise spectrums. In order to guarantee a well behaved solution, we have to check the design against margin constraints subject to uncertainties. In case the optimal loop does not meet the required margin constraints subjected to uncertainties, it is shown how to apply a method taken from control theory to find a controller. Alternatively, if we restrict the solution to first or second order loops, we give a simple loop design procedure which may be sufficient in many cases. Extensions of the method are shown for using both pilot symbols and data symbols in the OFDM receiver for phase tracking. We compare our results to other methods commonly used in OFDM receivers and we show that a large improvement can be gained.