• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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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.

• Journal of Life Science
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• v.9 no.6
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• pp.728-732
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• 1999

The inhibitory effects of methanol extracts from wild mushrooms on mutagenicity induced by benzo(a)pyrene (B(a)P) and N-methyl-N-nitro- nitrosoguanidine(MNNG) were investigated using Salmonella typhimurium reversion assay. In Ames test, The methanol extracts of 11 mushrooms did not show any mutagenicity but The methanol extracts of Lactarius piperatus, Naematoloma fasciculare and Innotus xeranticus showed 40∼80% of inhibitory effect on the mutagenicity induced by indirect mutagen of B(a)P and also showed 60∼80% of antimutagenic activity toward MNNG irrespective of their concentrations.

• Management Science and Financial Engineering
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• v.17 no.2
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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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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• v.19 no.3
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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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.5 s.113
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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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• v.26 no.4
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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.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.450-455
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• 1998

Pine has been known as a traditional medicinal plant and as showing a physically beneficial function to a human being. Therefore, this study was performed to investigate the physiological activities of main pine neddles. Ethanol extracts from pinus needles did net exhibit any mutagenicity. On the contrary, inhibitory effects of ethanol extract were observed on mutagenicity induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), 4-nitroquinoline-1-oxide (4NQO), 3-amino-1,4-dimethyl-5H-pyrido-(4,3-b)indol (Trp-P-1) and benzo(a)pyrene $(B({\alpha})P)$ using Salmonella typhimurium reversion assay. On direct-acting mutagen (MNNG, 4NQO) and indirect-acting mutagen (Trp-P-1, $(B({\alpha})P)$, we observed higher inhibitory effect. Stepwise fractionation of the ethanol extract was done by using ether, chloroform, ethyl acetate, butanol and water to obtain effective fraction. Among them, water fractions $(100\;{\mu}g/plate)$ of Pinus thunbergii, Pinus rigida, Pinus densiflora and Pinus koraiensis showed high inhibition of 91.65%, 94.7%, 84.22% and 79.02%, respectively, on the mutagenicity of MNNG in Salmonella typhimurium TA100.

• The Korean Journal of Mycology
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• v.15 no.1
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• pp.19-22
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• 1987

This experiment was undertaken to investigate proper conditions for protoplast formation from Pleurotus spodoleucus. Novozym 234 was the most effective enzyme and a high yield of protoplasts was obtained. Combination of enzymes did not improve this result. Sucrose gave the best result to support the release and maintain the stability of protoplasts. The optimal reaction time of mycelium with the lytic mixture was 3 hrs. in shaking condition at 120 strokes $min-^1$. When mycelium of P. spodoleucus was cultured for 3 days on mushroom complete agar medium at $27^{\circ}C$, the formation of protoplasts was effective. The mushroom complete agar medium stabilized with 0.6 M sucrose was the most effective for reversion of protoplasts.

• KSBB Journal
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• v.5 no.3
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• pp.229-234
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• 1990

The isolation and regeneration of protoplasts are necessary for protoplast fusion of edible mushrooms. In this study, over 5$\times$107 ml-1 protoplasts of Agrocybe cylindracea were isolated using the method described by Yanagi. Enzyme mixture of cellulase Onozuka R10(2%), chitinase (0.2%) and Novozym 234(0.1%) was most effective for the isolation of protoplasts and the yield of protoplasts was 4.85$\times$107 ml-1. 0.6M sucrose was the most effective osmotic stabilizer. The maximum amount of mycelia and yield of protoplasts were obtained from 5~7 days cultured mycelia. In the case of 5~7% days cultured mycelia, the digestion time with lytic enzyme was 4~6 hours. ACM and MCM medium were most effective for the regeneration and reversion of protoplasts, and reversion frequency was 6.9~7.0%. 0.6M sucrose was most stable osmotic stabilizer.