• 한국식품영양과학회지
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• 제28권5호
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• pp.1092-1098
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• 1999

Gamma irradiation was applied to pork for improving its hygienic quality and evaluating its possible genotoxicity. The effective dose of irradiation was 3 kGy in pork for the sterilization of all contaminated microorganisms tested. After 8 weeks of storage at 5oC, no growth of microorganisms except for psychrophile and total aerobic bacteria was observed in the more than 3 kGy irradiated pork. The genotoxicity of high dose irradiated pork(30 kGy) was evaluated by Salmonella typhimurium reversion assay, chromosomal aberration test and in vivo micronucleus assay. The results were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535, TA1537. In chromosomal aberration tests with CHL cells and in vivo mouse micronucleus assay, no significant difference in the incidences of chromosomal aberration and micronuclei was seen between nonirradiated and 30 kGy irradiated porks. These results indicate that 30 kGy irradiated pork did not show any genotoxic effects under these experimental conditions.

• 생명과학회지
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• 제9권6호
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• pp.728-732
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• 1999

천연물질로부터 항돌연변이원성 물질 및 항암 물질 탐색을 위한 연구의 일환으로 11종의 국내산 야생 버섯류로 부터 메탄올 추출물을 제조한 후 Ames test를 이용하여 돌연변이 억제효과를 검토하였다. 실험에 사용한 농도에서 털이버섯(Lactarius piperatus), 노란다발독버섯(Naematolona fasciculare) 및 금빛시루뻔버섯(Innotus xeran- ticus)의 메탄올 추출물은 Salminella typhimurium Ta98 및 TA100 균주에서 추출물의 농도에 관계없이 간접변이원인 B(a)P에 대하여 40~80% 정도의 항돌연변이 효과를 나타내었으며, 직접변이원인 MNNG에 대해서는 60~80% 정도의 비교적 높은 돌연변이 억제효과를 나타내었다.

• Management Science and Financial Engineering
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• 제17권2호
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• pp.85-97
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• 2011

In this study we examine the long term behavior of stock returns. The analysis reveals that negative autocorrelations of the returns exist for a super-long horizon as long as 10 years. This pattern, however, contrasts to predictions of previous stock price models which include random walks. We suggest the introduction of a fractionally integrated process into a nonstationary component of stock prices, and demonstrate empirically the existence of the process in NYSE stock returns. The predicted values of autocorrelation from our stock price model confirm the super-long term behavior of the returns observed in regression, indicating that inefficiency in the stock market could remain for a long time.

• 한국식품영양과학회지
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• 제26권5호
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• pp.958-964
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• 1997

The three medicinal herbs-Curcuma longa Linne, Paeonia japonica Miyabe, Scutellaria baikalensis George-irradiated with gamma rays have been tested for their possible genotoxicity. The methanol-soluble and water-soluble fractions of the 10kGy gamma-iradiated herbs were examined in the Salmonella typhimurium histidine reversion assy(Ames test) using S. typhimurium TA98, TA100 and TA102 as tester strains. No mutabenicity was detected in this assay with or without metabolic activation. The safety of the herbs irradiated with gamma rays at practical doses needs to be evaluated in further tests of genotoxicity in vivo and chronic and reproductive toxicity.

• Elastomers and Composites
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• 제19권3호
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• pp.163-177
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• 1984

The effect of curing temperature increase and sulfur amount added were studied with natural and synthetic rubbers. Also, the effects of TMTD, MBTS and mixture of zinc soaps of high molecular fatty acids added to natural rubber were investigated respectively. The experimental results showed that, in the case of the conventional curing ($145^{\circ}C$), natural rubber, compared with synthetic rubber, gave higher values in elongation, tensile strength, cure rate, and lower values in modulus change. But, at high temperature curing ($180^{\circ}C$), natural rubber showed faster reversion rate, and higher heat build-up compared to synthetic rubber, than in the conventional curing. Also, natural rubber produced at high temperature showed severe degradation in hardness and tensile strength before heat-aging as well as in hardness, modulus and tensile strength after heat-aging. Improved reversion effect was obtained with natural rubber either by blending mixture of zinc soaps of high molecular acids or by applying semi-efficient vulcanization system.

• 펄프종이기술
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• 제37권5호통권113호
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• pp.15-24
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• 2005

Different types of antioxidants compounds were prepared economically from natural sources. Application of these compounds towards photo stabilization of high yield bagasse pulp has been investigated. It was found that potato peel antioxidant followed by clove volatile oil provides lower brightness reversion and better photo stabilization effect for paper made from high yield bagasse pulp after exposure to UV lights in comparison with butyl hydroxy anisol or chamomile volatile oil.

• Journal of Chest Surgery
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• 제26권4호
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• pp.249-254
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• 1993

Atrial fibrillation is commonly associated with organic mitral valve disease including rheumatic valvular heart diasease or mitral valve prolapse and so forth. Although spontaneous sinus reversion may occur in some patients after mitral valve operation, recurrence of atrial fibrillation is the rule in most of these patients. We have tried to maintain sinus rhythm after mital valve operation with oral quinidine therapy, and we will show the efficacy of this therapy in this report. From January 1986 to August 1992, 60 patients of mitral valvular heart disease, who had had atrial fibrillation preoperatively and gained sinus rhythm postoperatively, were selected for this study. These patients were divided into 2 groups: Control group [n=30] and Quinidine trial group [n=30]. The age,sex, duration of symptoms,left atrial size and other risk factors of the reversion to atrial fibrillation were adjusted to be similar between the two groups. The maintenance rate of sinus rhythm was calculated by Kaplan-Meier method, and the rate was significantly higher in quinidine trial group than in control group [ p=0.0001 ]. Univariate analysis was performed on the risk factors of reversion to atrial fibrillation, and the difference of maintenance rate between the two groups were corrected with this result: the difference was still statistically significant [ p=0.0205 ]. The quinidine levels were measured in postoperative days, and there were no difference of serum quinidine level between the quinidine success group and quinidine failure group. In conslusion, oral quinidine therapy was effective for the maintenance of sinus rhythm after mitral valve operation compared to control group, and there was no correlation between the serum quinidine level and clinical efficacy of quinidine therpy.

• 한국식품과학회지
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• 제30권2호
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• pp.450-455
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• 1998

한국에 널리 분포하고 있는 곰솔, 리기다, 잣나무, 적송의 에탄올추출물과 각 용매 분획물을 이용하여, in vitro assay로서 spore rec-assay와 Salmonella typhimurium reversion assay법으로 시료자체 변이원성 유무와 4가지 양성변이원 물질(MNNG, 4NQO, Trp-P-1 및 B(a)p)에 대한 돌연변이 억제효과를 고찰하였다. 곰솔, 리기다, 잣나무, 적송의 에탄올 추출물은 spore rec-assay와 S. typhimurium를 이용한 mutagenicity assay에서 변이원성을 나타내지 않았다. 돌연변이 억제 시험에서는 4가지 시료 모두 농도 증가에 따른 억제율을 나타내었고 또 각각의 시료들의 분획물 중 잣나무와 소나무의 에테르 분획물들이 간접변이원인 Trp-P-1의 변이원성에 대하여 다른 분획물에 비하여 높은 억제율을 보여주었다.

• 한국균학회지
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• 제15권1호
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• pp.19-22
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• 1987

식용버섯의 일종인 참느타리버섯 P. spodoleucus의 유전육종을 위하여 균사체로부터의 원형질체 분리와 분리된 원형질체의 환원에 영향을 미치는 몇가지 요인을 조사한 결과는 다음과 같다. 1. 원형질체 분리에 알맞는 효소로는 Novozym 234이며, 삼투압 조절제로는 0.6 M sucrose, 효소처리 시간은 3 시간이었다. 그리고 균사체 배양일수는 exponential phase인 3 일이었으며, colony의 $cm^2$당 원형질체 생성수는 $3.43{\times}10^{5}ml^{-1}$이었다. 2. 원형질체 환원에 알맞는 삼투압 조절제는 0.6 M sucrose이며, 환원율은 0.01-0.28%였다.

• KSBB Journal
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• 제5권3호
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• pp.229-234
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• 1990

Pseudomonas elodea 에 의한 Gellan gum생산시 이에 관련된 기초자료를 얻기 위하여 회분식 및 연속식 발효를 하였다. 회분식 배양의 결과로부터 비성장 속도는 $0.16hr^-^1$이었으며 72시간 배양후의 점도는 4500cp, 생성물 농도 0.7g dry weught/100g broth, 및 생산성은 0.08g dry weight/1/hr이었다. 연속식 배양을 통하여 최적 탄소원과 질소원의 농도비(3.0mg-carbon/mg-nitrogen)를 결정하였으며 Gellan gum의 최대 생성속도는 희석율 $0.14hr^-^1$에서 0.6g dry weight/l/hr이었다. 이러한 조건에서 각종 metabolic paeameter값을 계산하였다. 또한 배양액의 유변학적 특성은 Casson equation에 잘 부합됨을 확인하였고, 배양액의 점도와 산소전달계수를 측정하여 고점도 배양시 산소전달의 장애현상을 조사하였다.