• 한국환경농학회지
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• 제18권3호
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• pp.245-249
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• 1999

저선량의 감마선이 조사된 대두종자로부터 자라난 작물체에 인공 산성강우가 미치는 영향을 알아보기 위하여 황금콩과 방사콩의 생육 양상을 조사한 결과 초장은 감마선조사 선량에 따라서만 생육 차이를 보였을 뿐 산성강우 무처리구(pH 6.00)와 처리구(pH 2.45와 2.20)간에는 큰 차이를 보이지 않았으며, 종자 저장기간에 따라서도 큰 차이를 보이지 않았다. 그러나 황금콩의 경우 생육 촉진을 위한 적정 조사선량이 산성강우 무처리구에 비해 처리구에서 낮아지는 경향을 보였다. 또한 피해 병징 양상은 산성강우 pH 2.20 처리구에서 심하게 나타났으며 방사콩에 비해 황금콩에서 산성강우 내성 효과가 컸으며, 종자 저장기간에 따라서도 차이를 보여 1995년산에 비해 1997년산 작물체에서 효과가 큰 것으로 나타났다. 그러나 방사콩의 생육 양상은 산성강우 처리 농도와 감마선 조사에 따라 큰 차이를 보이지 않았다.

• 한국자원식물학회지
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• 제29권3호
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• pp.289-296
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• 2016

This study was executed to evaluate the immune activity, nitrite scavenging activity and ABTS radical scavenging activity against extracts of various concentration of ethanol solvent from Codonopsis lanceolata cultured at 6 local regions. The immune responses from both human T and B cell line was significantly enhanced in the cell growth compared to control while the cell growth was influenced at a certain period of culture. The results revealed that the cell growth of both human T and B cell was altered in a time dependent manner. The nitrite scavenging activity of ethanol extracts from various solvent concentration of C. lanceolata were affected by pH. At a pH of 1.2, the nitrite scavenging effect of all of the extracts tested observed higher than that of the other two pH ranges. There was no distinct detection of nitrite scavenging effects of the pH range 6.0. The ABTS radical scavenging activity was progressively increased in a dose-dependent manner, and the activity was the highest in 100% ethanol extract. The result from this investigation suggests that the extract of Codonopsis lanceolata could be an addition to basic medicine for immune modulation and natural food additives.

• 한국식품영양과학회지
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• 제27권3호
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• pp.425-432
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• 1998

The strain producing L-lactic acid from starch was isolated from kimchi. The isolated strain was identified as a homofermentative Streptococcus sp. through its morphological, cultural, biochemical characteristics, and named Streptococcus sp. JEJ-6. Lactic acids are of two types, one L-specific and the other D-specific form in a stereospecific form. Streptococcus sp. JEJ-6 produced selectively L-lactic acid from all of the tested carbon sources. The optimum conditions for the L-lactic acid production from the isolated microorganism were determined. For the maximum yield of L-lactic acid from Streptococcus sp. JEJ-6, the cell should be harvested at the early stationary phase, and the growth temperature, pH, and NaCl concentration should be 37$^{\circ}C$, pH 7.0 and 0.1%, respectively. 4% Soluble starch as substrate and organic nitrogen sources such as peptone and yeast extract should be used for the best yield. The optimum pH of the nicotinamide adenine dinucleotide(NAD)-dependent and NAD-independent lactate dehydrogenase(LDH) activities was pH 8.5 and pH 7.0, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.884-891
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• 2005

This paper describes the purification and properties of a multicatalytic proteinase complex, proteasome, from bovine skeletal muscle, in comparision with proteasome prepared from other species or organs. The purified bovine skeletal muscle proteasome exhibited a single band on polyacrylamide gel electrophoresis under nondenaturing conditions. Bovine skeletal muscle proteasome degraded synthetic peptides maximally at pH 8.0. Relative to pH 8.0, activities were gradually decreased with the lowering pH, but the extent of decrease was substrate-dependent, and the activity at pH 5.5 still retained 78-10% of the activity at pH 8.0, indicating the possibility that the proteasome is active in muscle during aging. When the proteasome was heated at 60$^{\circ}C$ for 15 or 30 min and treated in the presence of 0.0125% SDS, the activity increased over 1.8 and 3.1 times (LLVY (Suc-Leu-Leu-Val-Tyr-NH-Mec) as a substrate), respectively. These results (activation with heat or SDS) indicate that the hydrolytic activity of proteasome was stimulated under mild denaturing conditions. The characteristics of the bovine skeletal muscle proteasome obtained in our experiment were almost the same as those of the proteasome prepared from other species or organs.

• 상하수도학회지
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• 제14권4호
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• pp.343-349
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• 2000

Techniques such as dissolved air flotation and electroflotation, which utilize micro bubbles, are increasingly used for water and wastewater treatment. Most studies have concentrated on particle characteristics. Pretreatments that manipulate particle size and zeta potential were considered important. A recent study, which modeled the collision mechanism between micro bubbles and particles in dissolved air flotation, suggested bubble characteristics should also be important. Hydrogen micro bubbles were generated electrolytically and their zeta potentials measured under various conditions using a novel electrophoresis method. Effects of several parameters were investigated. Bubble zeta potentials were found to be pH dependent, and to have a negative value around neutral pH, becoming zero or positive at lower pH. The pH at zero zeta potential was 5.0 under study conditions. Using artificial solution and tap water, at fixed pH, bubble zeta potentials varied with solution composition. Zeta potentia]s of bubbles were affected by the types of cations and anions in solution but not by the voltage applied. These findings will help improve efficiencies of particle removal processes that utilize micro bubbles. As bubble zeta potential varies with solution composition, it needs to be measured for each composition to understand those effects, which increase removal efficiency.

• Carbon letters
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• 제7권1호
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• pp.1-8
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• 2006

The activated carbon "C" was obtained by carbonization followed by activation with steam at 40% of burn-off. Oxidized carbons C-N, C-P and C-H were obtained by oxidizing the activated carbon C with concentrated nitric acid, ammonium peroxysulfate and hydrogen peroxide, respectively. The textural properties of the carbons were determined from nitrogen adsorption at 77 K. The acidic surface functional groups were determined by pH titration, base neutralization capacity and electrophoretic mobility measurements. The cation exchange capacities of un-oxidized and oxidized carbons were determined by the removal of Cu(II) and Ni(II) from their aqueous solutions. The surface area and the total pore volume decreased but the pore radius increased by the treatment of activated carbon with oxidizing agents. These changes were more pronounced in case of oxidation with $HNO_3$. The surface pH of un-oxidized carbon was basic whereas those of the oxidized derivative were acidic. The removal of Cu(II) and Ni(II) was pH dependent and the maximum removal of the both ions was obtained at pH of 5-6. Cu(II) was more adsorbed, a phenomenon which was ascribed to its particular electronic configuration.

• KSBB Journal
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• 제15권6호
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• pp.630-634
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• 2000

에폭사이드 가수분해효소 활성이 우수한 Aspergillus niger 를 생촉매로 이용하여 업체선택적 가수분해 반응을 통해 라세믹 styrene oxide 기질로부터 광학활성 (S)-styrene oxide를 생산하는 실험을 수행하였다. (R)-styrene oxide 이성질체에 대한 초기 가수분해 속도에 영향을 주는 실험인자들인 pH, 반응온도, cosolvent 첨가량 등에 대해 중심합성계획법을 이용한 반응표면 분석을 통해 가수분해반응 속도를 향상시킬 수 있는 최적 반응조건을 결정하였다. pH 7.78, 반응온도 2 $28.32^{\circ}C$ 및 cosolvent 첨가량 2.4% (v/v)의 조건에서 약 10시간 정도의 반응을 통해 ee 값이 100%인 광학적으로 순수한 (S)-styrene oxide를 35% 정도(이론수율 = 50%)의 높은 수율로 얻을 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제11권1호
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• pp.31-36
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• 2007

To elucidate a potential molecular link between diabetes and atherosclerosis, we investigated the role of Janus tyrosine kinase(JAK) for NAD(P)H oxidase-derived superoxide generation in the enhanced proliferative capacity of vascular smooth muscle cells(VSMC) of Otsuka Long-Evans Tokushima Fatty(OLETF) rat, an animal model of type 2 diabetes. An enhanced proliferative response to 10% fetal bovine serum(FBS) and superoxide generation with an increased NAD(P)H oxidase activity were observed in diabetic(OLETF) VSMC. Both the enhanced proliferation and superoxide generation in diabetic VSMC were significantly attenuated by AG490, JAK2 inhibitor, and PP2, Src kinase inhibitor. Tyrosine phosphorylation of proteins in diabetic VSMC, especially JAK2, was increased compared to control VSMC. Furthermore, the enhanced NAD(P)H oxidase activity in diabetic VSMC was significantly attenuated by AG490 in a dose-dependent manner. Together, these results indicate that the signal pathway which leads to diabetes-associated activation of Src kinase/JAK is critically involved in the diabetic VSMC proliferation through NAD(P)H oxidase activation and superoxide generation.

• 한국식품과학회지
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• 제11권3호
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• pp.188-191
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• 1979

5-GMP의 열 분해 반응을 pH 5.52에서 7.00의 범위에서 조사하였다. 그 반응 속도는 일차 반응으로 나타났으며, 용액의 pH가 $pKa_2$일 때 반응속도가 가장 컸다. 5'-GMP의 분해 반응은 온도 의존성을 나타냈으며, $93^{\circ}C$에서 $108^{\circ}C$ 범위에서 Arrhenius식을 따르고 있었고, 반응 속도 상수는 $pKa_2$ 이상의 중성 용액 근처에서는 온도 및 pH의 함수로서 다음과 같이 표시되었다. $$K=4.19{\times}10^{26}\;Exp[-1.3(pH+E/RT)]$$

• 한국환경보건학회지
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• 제24권2호
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• pp.126-133
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• 1998

Effects of B(a)P on preimplantation mouse embryos in vitro were studied. Preimplantation mouse embryos were exposed to a concentration of 0.3, 1, 3 and 10 $\mu$M B(a)P for 72 hrs. The toxicological effects of B(a)P were evaluated by morphological observation of embryos up to the blastocyst stage, and by measuring DNA, RNA and protein synthesis by radioactive precursor incorporation. At 1 $\mu$M B(a)P did not affect preimplantation development but interfered with hatching and ICM formation. Suppressing effect of ICM formation was dose dependent. At the eight cell stage, the developmental rate was decreased at above 3 $\mu$M of B(a)P. At the blastocyst stage, attachment and trophoblast outgrowth were diminished at the 10 $\mu$M of B(a)P and ICM formation was decreased at 1 $\mu$M of B(a)P. Inner cell number of blastocyst was decreased dose dependently. So, number of ICM was one of the most sensitive and toxicological end point. The RNA incorporation rate of 0.1 $\mu ^3$H-uridine was dosedependent and the protein incroporation of 0.5 $\mu Ci ^{35}$S-methionine showed a significant decrease after 48 hrs. But the DNA incorporation rate of methyl-$^3$H thymidine was not affected. Our results suggested that B(a)P did not affect the DNA replication but transcription was inhibited by dose dependent manner. There delay of development during the blastocyst stage was mainly due to the inhibition of RNA synthesis followed by protein synthesis.