• Journal of Applied Biological Chemistry
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• 제60권4호
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• pp.307-311
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• 2017

본 연구는 제주 동백나무 어린 잎 메탄올 추출물과 에탄올 추출물의 페놀류 함량 및 항산화 활성에 대한 연구를 진행하였다. 메탄올 추출물과 에탄올 추출물의 총 폴리페놀과 플라보노이드 함량은 각각 74.9과 46.1 mg GAE/100 g 및 30.6과 21.4 mg RE/100 g이었다. 또한 추출물들은 DPPH, superoxide와 nitric oxide 라디컬 소거능, chelating 및 환원력을 가지는 것으로 나타났다. 이 결과들로 동백나무 어린 잎이 높은 항산화 효능을 가지고 있음을 알 수 있었으며, 차후 기능성 식품 및 약물 소재로서의 가능성을 검토할 필요가 있다.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권2호
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• pp.93-101
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• 2003

Scan design is a structured design-for-testability technique in which flip-flops are re-designed so that the flip-flops are chained in shift registers. The scan design cannot be used in a design with scan design rule violations without modifying the design. The most important scan design rule is concerning clock and reset signals to pins of the flip-flops or scan cells. Clock and Reset pins of every scan cell must be controllable from top-level ports. We propose a new technique to re-design gated clocks and resets which violate the scan design rule concerning the clock and reset pins. This technique substitutes synchronous sequential circuits for gated clock and reset designs, which removes the clock and reset rule violations and improves fault coverage of the design. The fault coverage is improved from $90.48\%$ to $100.00\%$, from $92.31\%$ to $100.00\%$, from $95.45\%$ to $100.00\%$, from $97.50\%$ to $100.00\%$ in a design with gated clocks and resets.

• 대한핵의학회지
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• 제31권4호
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• pp.427-432
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• 1997

Re-188은 반감기가 17시간이고 진단을 위한 영상화가 가능한 감마선(155keV)을 방출하며 치료용으로 적당한 베타선(2.12MeV)을 동시에 방출하여 혈관성형술 풍선에 넣어 조사하는 접촉 베타선 방출체 치료용 방사성핵종으로 유력하다. 이 연구에서는 Re-188-DTPA를 관상동맥풍선 성형술시 풍선에 주입하는 방사성 동위원소로 쓸 수 있을지 알기 위해 우선 표지법과 풍선에서 혈관내로 샜을 때의 생체내 분포를 조사하였다. Re-188과 DTPA를 표지하는 방법을 확립하였고 표지효율은 95%, 실온과 사람 혈청에서 안정하였다. 마우스의 체내분포와 랫트와 실험견에서 얻은 신장 시간방사능곡선이 Re-188-DTPA가 신장을 통해 빠르게 제거된다는 것을 밝혔다. 이러한 결과는 Re 188-DTPA를 관상동맥의 재협착을 방지하기 위해 관상동맥풍선 성형술시 풍선에 주입하는 방사성 동위원소로 사용하여도 좋음을 시사한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.83-86
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• 2002

Numerical simulations are conducted for laminar flow past a sphere rotating In the transverse direction, in order to investigate the effect of the rotation on the characteristics of flow over a sphere. The Reynolds numbers considered are Re=100, 250 and 300 based on the free-stream velocity and the sphere diameter, and the rotational speeds are in the range of $0{\leq}{\omega}{\leq}1$, where ${\omega}^{\ast}$ is the maximum velocity on the sphere surface normalized by the free-stream velocity. At ${\omega}^{\ast}=0$ (without rotation), the flow past the sphere experiences steady axisymmeoy, steady planar-symmetry and unsteady planar-symmetry, respectively, at Re=100, 250 and 300. However, with rotation, the flow becomes planar-symmetric for all the cases investigated and the symmetry plane is orthogonal to the axis of the rotation. The flow is also steady or unsteady depending on both the Reynolds number and the rotational speed, and the vortical structures behind the sphere are significantly modified by the rotation. For example, at Re=300, hairpin vortices completely disappear in the wake at ${\omega}^{\ast}=0.4\;and\;0.6$, and at ${\omega}^{\ast}=1$ vortical structures of a high frequency are newly generated due to the shear layer instability. It is also shown that with increasing rotational speed, the time-averaged drag and lift coefficients increase monotonically.

• 대한전자공학회논문지SD
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• 제39권4호
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• pp.84-92
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• 2002

최근의 FPGA는 매우 높은 집적도와 빠른 동작속도 때문에 많은 응용분야에서 널리 사용되고 있다. 그러나, FPGA에 구현된 설계를 디버깅하는 과정은, FPGA의 내부에 존재하는 수많은 신호선들을 탐침하는 과정이 매우 오랜 시간을 요하는 FPGA 재-컴파일을 최소 수 차례 이상 필요로 함으로서 많은 문제점을 가지고 있다. 본 논문에서는, 이와 같은 FPGA 디버깅의 문제점을 분석하고, 새로운 디버깅 방법을 제안한다. 제안되는 방법은 FPGA 내부에 존재1차는 모든 신호선들에 대한 100% 탐침을 한 차례의 FPGA 재-컴파일과정 없이도 수행하는 것을 가능하게 할 뿐만 아니라, 한번의 FPGA 컴파일 과정으로 최소 한 개의 설계 오류를 찾을 수 있도록 한다. 본 논문에서 제안된 방법은 실험을 통하여서도 매우 효과적이며 실용적임이 확인되었다.

• Journal of Ginseng Research
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• 제38권2호
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• pp.89-96
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• 2014

The protective effect of ginsenoside Re, isolated from ginseng berry, against acute gastric mucosal lesions was examined in rats with a single intraperitoneal injection of compound 48/80 (C48/80). Ginsenoside Re (20 mg/kg or 100 mg/kg) was orally administered 0.5 h prior to C48/80 treatment. Ginsenoside Re dose-dependently prevented gastric mucosal lesion development 3 h after C48/80 treatment. Increases in the activities of myeloperoxidase (MPO; an index of neutrophil infiltration) and xanthine oxidase (XO) and the content of thiobarbituric acid reactive substances (TBARS; an index of lipid peroxidation) and decreases in the contents of hexosamine (a marker of gastric mucus) and adherent mucus, which occurred in gastric mucosal tissues after C48/80 treatment, were significantly attenuated by ginsenoside Re. The elevation of Bax expression and the decrease in Bcl2 expression after C48/80 treatment were also attenuated by ginsenoside Re. Ginsenoside Re significantly attenuated all these changes 3 h after C48/80 treatment. These results indicate that orally administered ginsenoside Re protects against C48/80-induced acute gastric mucosal lesions in rats, possibly through its stimulatory action on gastric mucus synthesis and secretion, its inhibitory action on neutrophil infiltration, and enhanced lipid peroxidation in the gastric mucosal tissue.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1990년도 Proceedings of International Symposium on Korean Ginseng, 1990, Seoul, Korea
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• pp.58-64
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• 1990

The effects of ginseng saponins, G-Rbl and G-Rc on the rat liver LDH A-gene transcnptional activity was investigated during pro-replicative phase of rat liver after partial hepatectomy. Changes in LDH A-mRNA levels in regenerating rat liver after intraperitoneal administrations of G-Rbl of G-Rc were tested by slot blot hybridization methods. The results showed that G-Rbl (1 mg/100g B.W) and G-Rc (1 ma/100g B.W) caused marked increases of LDH A-mRNA contents by respectively 1.9- and 1.5-fold in rat liver at 5·hours after partial hepatectomy. Dose dependent effect of G-Rbl and G-Rc (1-25 mg/100g B.W) on the LDH A-mRNA levels on regenerating rat liver were also analyzed. The maximal in- creases of liver LDH A-mRNA levels were observed with the doses of 1 mg for G-Rbl and 5 mg for G-Rc However, when the administration doses of G-Kbl and G-Rc were increased to 20 mg, G-Rbl caused a marked decrease of LDH A-mRNA level to 61% of those in sham-operated rat liver In contrast, G-Rc slightly decreased the liver LDH A-mRNA contents by 30% as compared to those of the maximum value but still maintained 22% higher LDH A-mRNA levels then those of sham-operated rate liver. On the basis of these experimental results, we conclude that ginseng saponin, G-Rb 1 and G·Rc have stimulatory effect at the lower concentration (1 mg/100g B.W) and inhibitory effect at the higher concentration (20 moi loos 5.W) on the LDH A-gene transcription during regeneration of rat liver, Additionally we also investigated the stimulatory effects of ginsenosides on the protein and DNA synthetic activities in hepatocyte primary cell cultures isolated from regenerating rat liver. Both of G·Rc and -Re increased the synthetic rates of hepatocytes proteins and DNA at the administration doses of 50 ug and 100 ug/3 ml/dish respectively representing 1.3-1.6 fold increases. From these results we postulate that G-Rc and -Re may have a mitogen enhancer activity for the hepatocyte proliferation during rat liver regeneration period. Keywords Inductive effects of ginsenosides, G-Rb, -Rc, and -Re, rat LDH A-gene transcription, the sin thetic rate of proteins and DNA in regeneration rat liver.

• Wind and Structures
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• 제30권5호
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• pp.451-463
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• 2020

Two-dimensional numerical simulations are conducted at a low Reynolds number Re = 100 to investigate the near wake of three identical circular cylinders that are arranged in an equilateral triangular configuration. The incident angle of the three-cylinder configuration with respect to incoming flow is varied from θ = 0° to 60°, while the spacing between adjacent cylinders (L) covers a wide range of L/D = 1.25-7.0, where D is diameter of the cylinder. Typical flow structures in the near wake of the three-cylinder configuration are identified, including a single Karman vortex street, bistable flip-flopping near wake, anti-phase and/or in-phase vortex shedding, shear layer reattachment, and vortex impingement, depending on the configuration (L/D, θ). The behavior of Strouhal number (St) is discussed in detail, echoing the distinct structures of near wake. Furthermore, fluid forces on the individual cylinders are examined, which, though highly depending on (L/D, θ), exhibit a close correlation to the near wake behavior.

• 한국전산유체공학회지
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• 제12권4호
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• pp.61-67
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• 2007

Numerical simulation of laminar flow over two spheres in a side-by-side arrangement is carried out to investigate the effect of the inter-sphere spacing on the flow characteristics. The Reynolds numbers considered are 100, 250, and 300, covering the steady axisymmetric, steady planar-symmetric, and unsteady planar-symmetric flows in the case of a single sphere. Results show that the drag and lift coefficients and wake structures are significantly modified depending on both the Reynolds number and the spacing between the spheres. At Re=100, the flow is steady planar-symmetric irrespective of the spacing, but it shows some variation according to the spacing at Re=250 and 300. That is, the flow maintains planar symmetry of the single-sphere wake at large spacings, while it loses the symmetry at small spacings due to the generation of new asymmetric vortical structures. It is also shown that the drag and lift coefficients generally increase with decreasing inter-sphere spacing because the high pressure region is formed near the gap between the spheres.

• Biomolecules & Therapeutics
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• 제22권5호
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• pp.420-425
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• 2014

Esophageal reflux of gastric contents causes esophageal mucosal damage and inflammation. Recent studies show that oxygen-derived free radicals mediate mucosal damage in reflux esophagitis (RE). Chlorogenic acid (CGA), an ester of caffeic acid and quinic acid, is one of the most abundant polyphenols in the human diet and possesses anti-inflammatory, antibacterial and anti-oxidant activities. In this context, we investigated the effects of CGA against experimental RE in rats. RE was produced by ligating the transitional region between the forestomach and the glandular portion and covering the duodenum near the pylorus ring with a small piece of catheter. CGA (10, 30 and 100 mg/kg) and omeprazole (positive control, 10 mg/kg) were administered orally 48 h after the RE operation for 12 days. CGA reduced the severity of esophageal lesions, and this beneficial effect was confirmed by histopathological observations. CGA reduced esophageal lipid peroxidation and increased the reduced glutathione/oxidized glutathione ratio. CGA attenuated increases in the serum level of tumor necrosis factor-${\alpha}$, and expressions of inducible nitric oxide synthase and cyclooxygenase-2 protein. CGA alleviates RE-induced mucosal injury, and this protection is associated with reduced oxidative stress and the anti-inflammatory properties of CGA.