• Journal of KSNVE
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• v.1 no.1
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• pp.45-52
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• 1991

The dynamic properties of primary-secondary structural systems are examined using analytical expressions for the modal properties. The analysis begins with a Lagrange multiplier formulation to develop a characteristic equation in terms of primary system mobilities and secondary system impedances. The complexity of the characteristic equation by developing new method, frequency window method. It is shown that the reduction of complexity can only be obtained by a reduction of accuracy, but by retaining the dominant effects of the dynamics problem, the loss of accuracy is not excessive. The reduced problem is examined further to develop simple expressions for the modal properties which provide insight into the resonance characteristics of the primary-secondary system problem. The results are useful as a complement to existing computational techniques for understanding and interpreting dynamic analysis results.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.1
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• pp.74-80
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• 1990

The transconductance of short channel LDD MOSFETs in the saturation region (high Vd)has shown different characteristics from that of conventional device. The transconductance in saturation regime of short channel LDD MOSFETs is reduced from maximum value at higher gate voltage. This decline is analyzed as the velocity saturation effects of carrier at LDD region but accurate analytical expressions for the drain current Idsat and the transconductance Gmsat in the saturation regime are still not in existence. Recently the drain current dependence of parasitic source resistance Rs has been modeled from the velocity saturation of carriers in LDD region. In this study, we approximate that Rmsat that Rs is linearly dependent on the applied gate voltage. Analytical expressions for Idsat and Gmsat obtained from this approximation show the same general behavior as experimental results of short channel LDD NMOSFETs.

• Structural Engineering and Mechanics
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• v.8 no.3
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• pp.243-256
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• 1999

Using appropriate transformations, the differential equation for flexural free vibration of a cantilever bar with variably distributed mass and stiffness is reduced to a Bessel's equation or an ordinary differential equation with constant coefficients by selecting suitable expressions, such as power functions and exponential functions, for the distributions of stiffness and mass. The general solutions for flexural free vibration of one-step bar with variable cross-section are derived and used to obtain the frequency equation of multi-step cantilever bars. The new exact approach is presented which combines the transfer matrix method and closed form solutions of one step bars. Two numerical examples demonstrate that the calculated natural frequencies and mode shapes of a 27-storey building and a television transmission tower are in good agreement with the corresponding experimental data. It is also shown through the numerical examples that the selected expressions are suitable for describing the distributions of stiffness and mass of typical tall buildings and high-rise structures.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.54-60
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• 2021

Monte-Carlo GO is a computer GO program that is sufficiently competent without using knowledge expressions of IGO. Although it is computationally intensive, the computational complexity can be reduced by properly pruning the IGO game tree. Here, I achieve this by using a potential model based on the knowledge expressions of IGO. The potential model treats GO stones as potentials. A specific potential distribution on the GO board results from a unique arrangement of stones on the board. Pruning using the potential model categorizes legal moves into effective and ineffective moves in accordance with the potential threshold. Here, certain pruning strategies based on potentials and potential gradients are experimentally evaluated. For different-sized boards, including an official-sized board, the effects of pruning strategies are evaluated in terms of their robustness. I successfully demonstrate pruning using a potential model to reduce the computational complexity of GO as well as the robustness of this effect across different-sized boards.

• Molecules and Cells
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• v.22 no.1
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• pp.104-112
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• 2006

We previously reported that DA-9601, ethanol herbal extract of Artemisia asiatica, inhibited histamine and leukotriene releases in guinea pig lung mast cells activated with specific antigen/antibody reaction. This study aimed to evaluate the inhibitory effect of DA-9601 on the OVA-induced airway inflammation in allergic asthma mouse model. BALB/c mice were sensitized and challenged with OVA. DA-9601 was administered orally 1 h before every local OVA-challenge. OVA-specific serum IgE was measured by ELISA, recruitment of inflammatory cells in BAL fluids and lung tissues by Diff-Quik and H&E staining, respectively, the expressions of CD40, CD40L and VCAM-1 by immunohistochemistry, goblet cell hyperplasia by PAS staining, activities of MMPs by gelatin zymography, expressions of mRNA and proteins of cytokines by RT-PCR and ELISA, activities of MAP kinases by western blot, and activity of NF-${\kappa}B$ by EMSA. DA-9601 reduced IgE level, recruitment of inflammatory cells into the BAL fluid and lung tissues, expressions of CD40, CD40L and VCAM-1 molecules, goblet cell hyperplasia, MMPs activity, expressions of mRNA and productions of various cytokines, activities of MAP kinases and NK-${\kappa}B$ increased from OVA-challenged mice. These data suggest that DA-9601 may be developed as a clinical therapeutic agent in allergic diseases due to suppressing the airway allergic inflammation via regulation of various cellular molecules expressed by MAP kinases/NF-${\kappa}B$ pathway.

• Korean Journal of Acupuncture
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• v.31 no.4
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• pp.168-178
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• 2014

Objectives : Mahuang-Chuanwu(Mahwang-Cheonoh) Pharmacopuncture(MCP) has been used to treat obesity in Clinical Korean Medicine. MCP solution(MCPS) is also expected to have strong anti-obesity activities. However, little is known about the mechanisms of its inhibitory effects on adipocyte differentiation and lipogenesis. Methods : In the present study, we examined the effects of MCPS on differentiation and lipogenesis of 3T3-L1 adipocytes. To elucidate the mechanism of the effects of MCPS on lowering lipid content in 3T3-L1 adipocytes, we examined whether MCPS modulates the expressions of transcription factors to induce lipogenesis and adipogenic genes related to regulate the accumulation of lipids. Results : Our results showed that MCPS significantly inhibited differentiation and lipogenesis of 3T3-L1 adipocytes in a dose-dependent manner. MCPS suppressed the mRNA expressions of cytidine-cytidine-adenosine-adenosine-thymidine(CCAAT)/enhancer binding proteins ${\alpha}$($C/EBP{\alpha}$), C/EBP ${\beta}$, $C/EBP{\delta}$, and peroxisome proliferator-activated receptor ${\gamma}$($PPAR{\gamma}$) genes related to the induction of adipose differentiation. MCPS inhibited the mRNA expressions of adipose-specific aP2, adipsin, lipoprotein lipase(LPL), CD36, TGF-${\beta}$, and leptin genes related to the fat formation. MCPS downregulated the mRNA expressions of liver X receptor(LXR) ${\alpha}$ and fatty acid synthase(FAS) genes related to the induction of lipogenesis. In addition, MCPS reduced the production of adipocyte-induced pro-inflammatory cytokines. Conclusions : MCPS could regulate the accumulation of lipids and expression of adipogenic genes via inhibition of transcript factors related to induction of adipose differentiation.

• Nutrition Research and Practice
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• v.15 no.4
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• pp.444-455
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• 2021

BACKGROUND/OBJECTIVES: Adipocytes undergo angiogenesis to receive nutrients and oxygen needed for adipocyte' growth and differentiation. No study relating quercetin with angiogenesis in adipocytes exists. Therefore, this study investigated the role of quercetin on adipogenesis in 3T3-L1 cells, acting through matrix metalloproteinases (MMPs). MATERIALS/METHODS: After proliferating preadipocytes into adipocytes, various quercetin concentrations were added to adipocytes, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to evaluate cell proliferation. Glycerol-3-phosphate dehydrogenase (GPDH) activity was investigated as an indicator of fat accumulation. The mRNA expressions of transcription factors related to adipocyte differentiation, CCAAT/enhancer-binding proteins (C/EBPs), peroxisomal proliferatoractivated receptors (PPAR)-γ, and adipocyte protein 2 (aP2), were investigated. The mRNA expressions of proteins related to angiogenesis, vascular endothelial growth factor (VEGF)-α, vascular endothelial growth factor receptor (VEGFR)-2, MMP-2, and MMP-9, were investigated. Enzyme activities and concentrations of MMP-2 and MMP-9 were also measured. RESULTS: Quercetin treatment suppressed fat accumulation and the expressions of adipocyte differentiation-related genes (C/EBPα, C/EBPβ, PPAR-γ, and aP2) in a concentration-dependent manner in 3T3-L1 cells. Quercetin treatments reduced the mRNA expressions of VEGF-α, VEGFR-2, MMP-2, and MMP-9 in 3T3-L1 cells. The activities and concentrations of MMP-2 and MMP-9 were also decreased significantly as the concentration of quercetin increased. CONCLUSIONS: The results confirm that quercetin inhibits adipose tissue differentiation and fat accumulation in 3T3-L1 cells, which could occur through inhibition of the angiogenesis process related to MMPs.

• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.210-218
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• 2023

Prostate cancer is the fifth leading cause of cancer-related mortality in men, primarily because of treatment resistance, recurrence, and metastasis. In the present study, we investigated the role of paracrine interleukin-8 (IL-8) in the antagonistic expression of IL-8 and androgen receptor (AR), and the contribution of IL-8 to prostate cancer aggressiveness. In hormone-responsive LNCaP cells that do not express IL-8, recombinant IL-8 treatment significantly increased expressions of IL-8, CXC chemokine receptor 2 (CXCR2), matrix metalloproteinase (MMP)-2/9, Snail, and vimentin. IL-8 treatment significantly decreased AR and E-cadherin expression. IL-8-induced gene expression changes were suppressed by navarixin, a CXCR1/2 inhibitor, and gallein, a Gβγ inhibitor. In PC-3 androgen-refractory prostate cancer cells, IL-8 knockdown reduced expressions of CXCR2, MMP-2/9, Snail, and vimentin, and increased AR and E-cadherin expressions at the mRNA and protein levels. Co-culture with MEG-01 human megakaryocytic cells secreting high levels of IL-8 induced gene expression changes in both LNCaP and PC-3 cells, similar to those induced by IL-8 treatment. The altered gene expressions were accompanied by significant activation of transcription factor Snail in LNCaP and PC-3 cells. Treatment with the CXCR blocker navarixin inhibited the invasion of PC-3 cells but not LNCaP cells. However, invasion induced by MEG-01 was inhibited by navarixin in both LNCaP and PC-3 cells. The collective findings demonstrate that IL-8 enhances CXCR2 expression, which antagonistically regulates AR expression. More importantly, through changes in IL-8/CXCR2-regulated gene expression, IL-8 induces antiandrogen therapy resistance and epithelial-mesenchymal transition in prostate cancer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1681-1687
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• 2014

In the present study, we investigated the effect of ethyl acetate fraction from 50% ethanol extract of fermented Curcuma longa L. (FCEE) on lipid metabolism in 3T3-L1 cells. The safety range of FCEE was up to $300{\mu}g/mL$. Effects of FCEE on lipid accumulation and intracellular triglyceride (TG) content in 3T3-L1 cells were examined by Oil Red O staining and AdipoRed assay. Compared to adipocytes, lipid accumulation and intracellular TG content were significantly reduced by 10.2% and 13.7%, respectively, upon FCEE treatment at a concentration of $200{\mu}g/mL$. Glucose uptake by 3T3-L1 cells was significantly reduced by 36.6% compared to adipocytes at a concentration of $200{\mu}g/mL$. On day 8, free glycerol release into the culture medium was significantly reduced compared to adipocytes at concentrations of 50, 100, and $200{\mu}g/mL$ of FCEE. FCEE significantly stimulated RNA expression of AMP-activated protein kinase (AMPK) and suppressed mRNA expressions of sterol regulatory element-binding protein-1c (SREBP-1c), CCAAT/enhancer binding proteins ${\alpha}$ ($C/EBP{\alpha}$), and peroxisome proliferator- activated receptor ${\gamma}$ ($PPAR{\gamma}$) in 3T3-L1 cells. These results suggest that FCEE inhibits adipogenesis through activation of AMPK mRNA expressions and inhibition of SREBP-1c, $C/EBP{\alpha}$, and $PPAR{\gamma}$ mRNA expressions.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.501-508
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• 2014

BACKGROUND/OBJECTIVES: Rubus Coreanus Miquel (RCM), used as a traditional Korean medicine, reduces chronic inflammatory diseases such as cancer and rheumatoid arthritis. However, its mechanism has not been elucidated. In this study, we examine the anti-inflammatory effects of RCM and their possible mechanisms using RAW 264.7 cells. MATERIALS/METHODS: Unripe RCM ethanol extract (UE), unripe RCM water extract (UH), ripe RCM ethanol extract (RE), and ripe RCM water extract (RH) were prepared. Inflammatory response was induced with LPS treatment, and expression of pro-inflammatory mediators (iNOS, COX-2, TNF-${\alpha}$, IL-$1{\beta}$, and IL-6) and NO and $PGE_2$ productions were assessed. To determine the anti-inflammatory mechanism of RCM, we measured NF-${\kappa}B$ and MAPK activities. RESULTS: UE and UH treatment significantly reduced NF-${\kappa}B$ activation and JNK and p38 phosphorylation and reduced transcriptional activities decreased iNOS, COX-2, and pro-inflammatory cytokines expressions, and NO and $PGE_2$ productions. RE and RH treatments reduced IL-$1{\beta}$ and IL-6 expressions through suppressions of JNK and p38 phosphorylation. CONCLUSIONS: In this study, we showed that RCM had anti-inflammatory effects by suppression of pro-inflammatory mediator expressions. Especially, unripe RCM showed strong anti-inflammatory effects through suppression of NF-${\kappa}B$ and MAPK activation. These findings suggest that unripe RCM might be used as a potential functional material to reduce chronic inflammatory responses.