• 대한수학회논문집
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• 제21권4호
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• pp.759-769
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• 2006

Let L : $C\;\rightarrow\;C$ be a hyperbolic automorphism. Then the hyperbolic toral automorphism $L_A\;T^2\;\rightarrow\;T^2$, induced by L, is a chaotic map ([2] pg.192). We characterize hyperbolic toral automorphisms by proving the converse of the above statement.

• Asian-Australasian Journal of Animal Sciences
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• 제22권6호
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• pp.788-795
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• 2009

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis under various physiological and pathological conditions. We found that the VEGF isoforms VEGF120, VEGF164, and VEGF188 were expressed in the bovine mammary gland and bovine mammary epithelial cells (bMECs). Expression of VEGF in the mammary gland was significantly higher during the lactation period than during the dry period. Although dexamethasone or prolactin alone had little effect on the expression of VEGF, that in dexamethasone-treated cells was significantly induced after additional treatment with prolactin. Furthermore, the VEGF expression induced by the combination of dexamethasone and prolactin was reduced by PD98059 in a dose-dependent manner. This combination also stimulated the phosphorylation of p44/p42 MAP kinase in these cells. These results strongly suggest that the combination of dexamethasone and prolactin stimulates VEGF expression in bMECs via p44/p42 MAP kinase.

• Archives of Pharmacal Research
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• 제27권4호
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• pp.429-435
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• 2004

Ginseng has an anti-cancer effect in several cancer models. This study was to characterize active constituents of ginseng and their effects on proliferation of prostate cancer cell lines, LNCaP and PC3. Cell proliferation was measured by $[^3H]$thymidine incorporation, the intracellular calcium concentration by a dual-wavelength spectrophotometer system, effects on mite-gen-activated protein (MAP) kinases by Western blotting, and cell attachment and morphologic changes were observed under a microscope. Among 11 ginsenosides tested, ginsenosides $Rg_3\;and\;Rh_2$ inhibited the proliferation of prostate cancer cells. $EC_{50}s\;of\;Rg_3\;and\;Rh_2$ on PC3 cells were $8.4{\mu}M\;and\;5.5{\mu}M$, respectively, and $14.1{\mu}M\;and\;4.4{\mu}M$ on LNCaP cells, respectively. Both ginsenosides induced cell detachment and modulated three modules of MAP kinases activities differently in LNCaP and PC3 cells. These results suggest that ginsenosides $Rg_3\;and\;Rh_2$-induced cell detachment and inhibition of the proliferation of prostate cancer cells may be associated with modulation of three modules of MAP kinases.

• 한국재난정보학회 논문집
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• 제17권4호
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• pp.694-709
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• 2021

연구목적: 지진에 의한 산사태 위험도 평가를 통하여 지진발생 전에는 산사태 예방사업, 지진발생 후에는 피해지 예측 및 복구 우선순위 선정으로 지진유발 산사태 피해저감을 효율적·선제적으로 하기 위한 기초자료를 제공하고자 수행하였다. 연구방법: 국외 선행연구를 분석하여 평가 방법론 검토와 평가 인자를 도출하고 국내 산사태 위험지도 활용성을 검토하였다. 또한 지진동 감쇠식을 이용하여 포항지역의 단층대 및 진앙지 기준으로 지진에 의한 산사태 위험지도를 시범 구축하였다. 연구결과: 지진에 의한 산사태 위험도 평가 연구는 중국이 전체의 44%, 이탈리아 16%, 미국 15%, 일본 10%, 대만 8% 순으로 나타났다. 평가 방법론으로 통계적 모형이 59%로 가장 많았고, 물리적 모형이 23%로 나타났다. 통계적 모형에 많이 사용된 인자는 고도, 단층대와의 거리, 경사도, 사면방향, 모암, 지형곡률로 나타났다. 현재 국내의 산사태 위험지도는 지형·지질·임상이 반영되는데 이를 활용한 지진에 의한 산사태 위험도 평가는 합리적인 것으로 나타났다. 포항지역에 단층대 및 진앙지 기준으로 산사태 위험도를 평가한 결과 기존의 낮은 등급이 높은 등급으로 변화하는 등 지진의 영향이 고려되었다. 결론: 광역 단위의 지진유발 산사태 위험도 평가를 위해서는 산사태 위험지도를 활용하는 것이 효율적이다. 단층대 기준의 위험지도는 지진에 의한 산사태 피해방지를 위한 예방사방사업 대상지 선정에 활용하고, 진앙지 기준의 위험지도는 지진이 발생한 이후 산사태 피해 현황을 조사하거나 피해지 복구 등 피해방지 대책 우선순위 선정의 효율적 사후관리에 활용할 수 있다.

• 한국연소학회지
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• 제17권1호
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• pp.48-57
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• 2012

Laminar lifted propane coflow-jet flames diluted with nitrogen were experimentally investigated to determine heat-loss-related self-excitation regimes in the flame stability map and elucidate the individual flame characteristics. There exists a critical lift-off height over which flame-stabilizing effect becomes minor, thereby causing a normal heat-loss-induced self-excitation with O(0.01 Hz). Air-coflowing can suppress the normal heat-loss-induced self-excitation through increase of a Peclet number; meanwhile it can enhance the normal heat-lossinduced self-excitation through reducing fuel concentration gradient and thereby decreasing the reaction rate of trailing diffusion flame. Below the critical lift-off height. the effect of flame stabilization is superior, leading to a coflow-modulated heat-loss-induced self-excitation with O(0.001 Hz). Over the critical lift-off height, the effect of reducing fuel concentration gradient is pronounced, so that the normal heat-loss-induced self-excitation is restored. A newly found prompt self-excitation, observed prior to a heat-loss-induced flame blowout, is discussed. Heat-loss-related self-excitations, obtained laminar lifted propane coflow-jet flames diluted with nitrogen, were characterized by the functional dependency of Strouhal number on related parameters. The critical lift-off height was also reasonably characterized by Peclet number and fuel mole fraction.

• Transactions on Control, Automation and Systems Engineering
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• 제1권1호
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• pp.62-68
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• 1999

FCM(Fuzzy Cognitive Map) is proposed for representing causal reasoning. Its structure allows systematic causal reasoning through a forward inference. Authors have already proposed a diagnostic system based on FCM to utilized to identify the true origin of fault by on-line pattern diagnosis. In FCM based fault diagnosis, Temporal Associative Memories (TAM) recall of FCM is utilized to identify the true origin of fault by on-line pattern match where predicted pattern sequences obtained from TAM recall of fault FCM models are compared with actually observed ones. In engineering processes, the propagation delays are induced by the dynamics of processes and may vary with variables involved. However, disregarding such propagation delays in FCM-based fault diagnosis may lead to erroneous diagnostic results. To solve the problem, a concept of FTCM(Fuzzy Time Cognitive Map) is introduced into FCM-based fault diagnosis in this work. Expecially, translation method of FTCM makes it possible to diagnose the fault for some discrete time. Simulation studies through two-tank system is carried out to verify the effectiveness of the proposed diagnostic scheme.

• BMB Reports
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• 제57권5호
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• pp.238-243
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• 2024

Bone marrow-derived mesenchymal stem cells (BM-MSCs) can differentiate into endothelial cells in an inflammatory microenvironment. However, the regulatory mechanisms underlying this process are not entirely understood. Here, we found that TIE2 in BM-MSCs was upregulated at the transcriptional level after stimulation with tumor necrosis factor-alpha (TNFα), a major pro-inflammatory cytokine. Additionally, the STAT-binding sequence within the proximal region of TIE2 was necessary for TNFα-induced TIE2 promoter activation. TIE2 and STAT3 knockdown reduced TNFα-induced endothelial tube formation in BM-MSCs. Among the major TNFα-activated MAP kinases (ERK1/2, JNK1/2, and p38 MAPK) in BM-MSCs, only inhibition of the p38 kinase abrogated TNFα-induced TIE2 upregulation by inhibiting the JAK-STAT signaling pathway. These findings suggest that p38 MAP contributes to the endothelial differentiation of BM-MSCs by activating the JAK-STAT-TIE2 signaling axis in the inflammatory microenvironment.

• 상하수도학회지
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• 제21권3호
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• pp.273-278
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• 2007

Modern society has moved from a phosphorus recycling loop, where animal manure and human wastes were spread on farming land to recycle nutrients, to a once-through system, where phosphates are extracted from mined, non-renewable phosphate rock and end up either in landfill(sewage sludge, incinerator ash) or in surface waters. In this research, crystallization of nitrogen and phosphate with natural sources of $Mg^{2+}$ in synthetic water was tested. The operational parameters of pH, mixing time, and the magnesium molar ratio were investigated to find optimal conditions of the MAP precipitation using synthetic wastewater. The removal efficiency of phosphate increased with pH up to 11. By MAP precipitaiton of the synthetic waste water, 94% of the phosphate were eliminated at pH 11. It was found that at least 10 minutes mixing time was required and 20 minutes mixing time was recommended for efficient phosphate removal. High efficiency removal of phosphate was possible when the magnesium molar ratio was 1.0~2.0. The comparative study of different magnesium sources showed that coagulants (PAC) was the more efficient sources than only magnesium. The result showed that 97% of phosphate removal. In conclusion, coagulants (PAC) induced crystallization of struvite and hydroxyapatite was shown to be a technically viable process that could prove cost effective for removing phosphate in wastewater.

• 대한수학회보
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• 제47권4호
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• pp.693-699
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• 2010

In this paper we show that the flat property of a left R-module does not imply (carry over) to the corresponding inverse polynomial module. Then we define an induced inverse polynomial module as an R[x]-module, i.e., given an R-linear map f : M $\rightarrow$ N of left R-modules, we define $N+x^{-1}M[x^{-1}]$ as a left R[x]-module. Given an exact sequence of left R-modules $$0\;{\rightarrow}\;N\;{\rightarrow}\;E^0\;{\rightarrow}\;E^1\;{\rightarrow}\;0$$, where $E^0$, $E^1$ injective, we show $E^1\;+\;x^{-1}E^0[[x^{-1}]]$ is not an injective left R[x]-module, while $E^0[[x^{-1}]]$ is an injective left R[x]-module. Make a left R-module N as a left R[x]-module by xN = 0. We show inj $dim_R$ N = n implies inj $dim_{R[x]}$ N = n + 1 by using the induced inverse polynomial modules and their properties.

• 대한본초학회지
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• 제24권3호
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• pp.139-146
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• 2009

Objectives : This study was conducted to investigate the effect of HTE001, a multi-herbal mixture consisting of 10 herbs, Cornus Frutus, Schizandrae Fructus, Rubi Fructus, Cnidi Fructus, Acanthopanacis senticosi Radix, Cinnamomi Cortex, Eucommiae Cortex, Allii Bulbus, Rehmanniae Radix and Ginseng Radix, on electrostimulation-induced penile erection in rats. Methods : Intracavernous pressure (ICP) and mean arterial blood pressure (MAP) were simultaneously monitored through electric stimulation of the cavernous nerve after the oral administration of HTE001 (30, 100, 300 mg/kg) in normal rats. Statistical analysis was performed on maximal intracavernous pressure (ICP), maximal intracavernous pressure/mean arterial blood pressure (ICP/MAP) ratio, and the area under the curve (AUC) of ICP/MAP ratio. Results : Oral administration of HTE001 300 mg/kg caused the ICP to increase in a frequency-dependent manner. And HTE001 300 mg/kg treatment group showed the highest value in the ICP/MAP ratio and the AUC value of the ICP/MAP ratio compared to the control group at 2 Hz, 6 Hz and 10 Hz, respectively without an effect on the mean arterial blood pressure under the same stimulation of the cavernous nerve. Conclusions : These results show that HTE001 improve penile erection and prolong the decay period in normal rats without affecting mean arterial blood pressure, and suggest that HTE001 could be a good therapeutic candidate to treat erectile dysfunction.