• Korean Journal of Food Science and Technology
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• v.54 no.4
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• pp.398-402
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• 2022

Black chokeberry (Aronia melanocarpa), a rich source of polyphenols, exerts hypocholesterolemic effects. However, little is known about its effects on the regulation of the hepatic cholesterol metabolism and the underlying mechanisms. In the present study, the effects of polyphenol-rich black chokeberry extract (CBE) on hepatic cholesterol metabolism were investigated by measuring the expression of genes involved in the absorption, de novo synthesis, and efflux of cholesterol in HepG2 cells. There was a significant reduction in the expression levels of genes involved in cholesterol metabolism, the low-density lipoprotein receptor, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and sterol regulatory element-binding protein 2, in CBE-treated HepG2 cells. Meanwhile, CBE increased the expression levels of genes involved in cholesterol and bile acid efflux. The expression levels of mitochondrial fatty acid oxidation genes increased, whereas those of lipogenic genes decreased following CBE treatment. These data suggest that the consumption of black chokeberry may be beneficial for the prevention of hypercholesterolemia.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.402-403
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• 2011

EMI 필터 설계 시 주로 사용되는 공통모드 초크의 경우 자화 인덕턴스로부터 공통모드 노이즈 감쇠를, 누설 인덕턴스로부터 차동모드 노이즈 감쇠를 기대할 수 있다. 이때, 누설인덕턴스가 너무 클 경우 차동모드 노이즈 감쇠에는 우수하지만, 전기/전자제품이 슬림화됨에 따라 공통모드 초크의 누설 자속과 전원공급기를 덮고 있는 금속덮개 사이에 자계 간섭에 의한 진동/소음문제가 발생될 수 있다. 본 논문에서는 누설자속을 조절할 수 있는 공통모드 초크의 코어형상 및 권선기법을 제안한다. 제안된 방법은 진동 및 소음을 제어할 수 있는 장점을 지니고 있다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.13.1-13.1
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• 2007

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.05a
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• pp.30.2-30.2
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• 2008

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.138-143
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• 2020

Black chokeberry (Aronia melanocarpa) has been suggested to exert antioxidant and anti-inflammatory effects due to its high polyphenol content. However, the mechanisms underlying the effects of black chokeberry on the alterations of nuclear factor E2-related factor 2 (NRF2) and nuclear factor κB (NF-κB) in macrophages have not been thoroughly studied. In this study, we investigated the protective effects of polyphenol-rich black chokeberry extract (CBE) against lipopolysaccharide (LPS)-induced oxidative stress and inflammation in RAW 264.7 macrophages. CBE significantly attenuated the increase of cellular reactive oxygen species (ROS) levels and the nuclear translocation of NRF-2 in LPS-stimulated macrophages. The mRNA abundances of Nrf2 and its downstream antioxidant genes were significantly decreased in LPS-stimulated macrophages. The LPS-induced mRNA expression of proinflammatory cytokines was significantly inhibited by reducing the nuclear translocation of NF-κB by CBE. These data suggest that black chokeberry may be used for the prevention of oxidative stress and inflammation-associated disease.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.166-167
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• 2009

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1349-1356
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• 2014

This study investigated the biological activities of 70% methanol extracts from black chokeberry and blueberry by measuring DPPH, superoxide anion and ABTS radical scavenging activities, metal chelating effect, reducing power, and nitrite scavenging activity. Extraction yields of black chokeberry and blueberry were 62.90% and 67.09%, respectively. Total polyphenol and total flavonoid contents were 117.20 mg/g and 32.50 mg/g for black chokeberry and 42.26 mg/g and 26.39 mg/g for blueberry, respectively. Black chokeberry had higher antioxidant activity than blueberry. DPPH and ABTS radical scavenging activities, nitrite scavenging activity, and metal chelating effect of black chokeberry were 98.29%, 96.68%, 97.64%, and 91.33%, respectively, at a concentration of 5 mg/mL, which were equal to those of ascorbic acid (positive control). These results suggest that black chokeberry has potent biological activities, and in the future, the availability of black chokeberry will increase in the field of value added food products.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.1
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• pp.57-65
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• 2003

As a compressed water is rapidly expanded through a nozzle, two-phase flow of vapor and liquid is formed in the nozzle due to the flash evaporation. In the present study, critical flow of two-phase fluids is analysized using an Isentropic-Homogeneous-Equilibrium model and a Leung model. Calculation results show that the choke of the two-phase flow can be two different types of continuous and discontinuous chokings. For the stagnation pressure below 10 Mpa it is found that the continuous choking, which is similar to the choking phenomenon of single-phase gas flow, is possible only when the degree of subcooling is less than 10K.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.97-103
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• 2000

In this paper band-stop filters that reject the undesired 3th and/or 5th harmonics generated from high frequency generator are analyzed using equivalent circuit concept, and optimized using iterative optimization algorithm. The length of the band-stop filter is setup initially a quarter of a wavelength of the harmonic, but initial filter structure is exactly unable to cutoff the harmonics because of the fringing effect at the discontinuous boundary. To reduce the mismatch between the cutoff frequency and the harmonics, iterative LMA(Levenberg-Marquardt Algorithm) is introduced and band-stop filters in coaxial line are optimized.

• Journal of IKEEE
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• v.22 no.1
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• pp.185-188
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• 2018

This paper describes the parasitic capacitance modeling according to the coil structure, section bobbin and winding method for hybrid choke coil with reduced parasitic capacitance capable of the EMI attenuation of broad bands from lower frequency to higher frequency applied in the EMI attenuation filter of LED-TV SMPS. Especially, the hybrid choke coil with reduced parasitic capacitance($C_p$) proposed in this paper can reduces the parasitic capacitance($C_p$) by adopting the winding methods of rectangular copper wire, compared to the conventional common mode choke coil with the winding method of automatic type. The first resonant frequency of the proposed hybrid choke coil has a tendency to increase as the parasitic capacitance is smaller and its impedance characteristics, especially in the high frequency bands, improves as the first resonant frequency increases. In the future, the proposed hybrid choke coil with reduced parasitic capacitance shows it can be actually utilized in not only LED-TV SMPS but also various applications such as LED Lighting, Note-PC Adapter, and so forth.