• The Korean Journal of Zoology
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• v.18 no.1
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• pp.41-49
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• 1975

Dose response and time dependence of DNA repair synthesis were investigated to determine the possible relationship between DNA repair synthesis and chromosome exchanges in $\\gamma$-ray irradiated BHK-21 and KB cell lines. DNA repair synthesis induced by $\\gamma$-ray was dose dependent up to 5kR, then leveling off occurred until 50 kR was reached. Time dependence of DNA repair synthesis was continued for up to 1$\\sim$2 hours after irradiation although the initial dose responses were cell line specific. Chromosome exchanges induced by $\\gamma$-ray showed different radiosensitivities in these cell lines and did not show a correlation with the DNA repair synthesis.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.171-176
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• 2012

In this study, a crosslinked poly(styrene-butadiene-styrene) [SBS] block copolymers were prepared by using gamma ray irradiation method. The effects of various radiation doses on the degree of crosslinking, thermo property, and morphology of crosslinked SBS block copolymer were investigated. The degree of crosslinking of crosslinked SBS block copolymers were measured by gel-fraction and FT-IR. It was found that the degree of crosslinking of crosslinked SBS block copolymers increases with increase of the irradiation dose while the TGA result shows that the initial degradation temperature of irradiated SBS block copolymer was shifted to lower temperature with increasing irradiation dose. These results indicate that degradation reaction also occurs when SBS block copolymer is exposed to gamma ray irradiation for crosslinking reaction. The SAXS and FE-SEM results indicate that the phase separation of the styrene block and butadiene block was reduced with increasing irradiation dose.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.432-433
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• 2018

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.249-253
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• 2004

CdS semiconductor quantum dot (QD) structures in aqueous solution are fabricated by using a gamma-ray irradiation technique and their optical absorption spectra are investigated. Cadmium sulfate solution, 2-mercaptoethanol solution, and reducing agent $e^{-}_{aq}$ are employed to produce CdS molecules, leading to CdS quantum dots. The measured linear absorption spectra before and after g-ray irradiation clearly show exciton peaks between 300 nm and 400 nm, which indicate the formation of CdS QD's. It is also observed that the exciton peaks are red-shifted with increasing the g-ray irradiation time from 5 min to 15 min. Therefore, it is concluded that the mean QD sizes can be systematically controlled with the dosage of the g-ray irradiation.

• Korean Journal of Food Science and Technology
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• v.2 no.1
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• pp.104-112
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• 1970

Korean Paldal variety rice, harvested November and hulled into polished and unpolished forms in April, 1969, packed in the straw bags and the kraft paper bags. Being irradiated with 10, 30 and 50 krad ${\gamma}-ray$, the samples were stored at room temperature for testing infestation, uric acid content, fat acidity, riboflavin content and panel test. The results are as follows. 1. The kraft bag lot with polished rice or unpolished rice manifested the apparent disinfestation with $30{\sim}50$ krad irradiation. On the other hand, in the straw bag lot the irradiation effects on disinfestation were weakened through summer on account of the second contamination. 2. The changes of uric acid content in rice were proportional to the state of infestation. 3. Fat acidity, which has a close relation with the rancidity of fat in rice, increased during storage and showed some increasing tendency in the irradiated lot with $30{\sim}50$ krad. 4. In comparison with the control lot, riboflavin content was not affected by 50 krad irradiation. 5. With 10, 30 and 50 krad dose, the irradiated lot should have no significant difference in taste, odour, color and viscosity for the panel test.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.143-148
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• 2000

This study was carried out to know the optimum dose of gamma-ray for the induction of mutation in vitro and the characteristics of the mutants induced by gamma-ray in persimmon (Diospyros kaki Thunb.). The LD50 (50% lethal dose) for in vitro shoots of the cultivar, Nishimurawase was between 1 krad and 2 krad and about 1 krad for the cultivar, Ichikikeijiro. As the dose of gamma-ray increased, the length of shoots decreased and necrosis of buds increased. For the cultivar, Nishmurawase, 37.5∼58.3% shoots rooted and the rooting rate and the number of roots per shoot was low in high gamma-ray. The irradiated young plants which were grown in the growth cabinet for 6 weeks were shorter in shoot length and had more branches than non-irradiated plants. The survival rate of irradiated plants grown in the green house for 3 months was 33%, while 77% for control plants.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.165-168
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• 2011

The antioxidant activity was analyzed in gamma-irradiated cooking juices. Because the activities of antioxidants have been attributed to various mechanisms, different assay methods including 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP), have been conducted and compared. All of these antioxidant assay showed that the antioxidant activity of cooking juice was increased by gamma-irradiation. To investigate this increase of antioxidative activity, the protein was extracted from cooking juices and its antioxidant activity was measured. From the results, it was thought that the modification of protein in cooking juiced by irradiation caused the increase of antioxidant activity of cooking juice. Therefore, gamma irradiation could be an promising method for a sterilization of cooking juice with increased antioxidant activity.

• Food Science and Preservation
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• v.8 no.1
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• pp.9-15
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• 2001

The effects of water soaking and gamma irradiation on the storage quality of chestnuts (Castanea crenata) were investigated. Chestnuts weirs soaked in water for 48 hrs at room temperature, irradiated at 0, 0.15, 0.25 and 0.35 kGy of $\^$60/Co gamma ray, and then stored at 0$\^{C}$ and 95$\pm$2% RH for 9 months. Spouting was observed at the end of storage only in chestnuts that were soaked and irradiated at below 0.25 kGy. Rotting was found from the early stage of storage in all pre-treatment conditions, but the rotting rate of soaked chestnuts was higher twice than unsoaked ones after 9 months of storage. Weight loss was lower in soaked than unseated samples regardless of irradiation dose. Loss of flesh firmness was appreciably retarded as irradiation dose increased. Total sugar content decreased slowly in irradiated samples at the later periods of storage. Gamma irradiation resulted in the decrease of vitamin C content immediately after treatment, but retarded its loss rate during storage. Soluble tannin content was not affected by gamma irradiation at scout inhibition doses.

• ETRI Journal
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• v.31 no.5
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• pp.604-606
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• 2009

The primary dose effects on an insulated gate bipolar transistor (IGBT) irradiated with a $^{60}Co$ gamma-ray source are found in both of the components of the threshold shifting due to oxide charge trapping in the MOS and the reduction of current gain in the bipolar transistor. In this letter, the IGBT macro-model incorporating irradiation is implemented, and the electrical characteristics are analyzed by SPICE simulation and experiments. In addition, the collector current characteristics as a function of gate emitter voltage, VGE, are compared with the model considering the radiation damage of different doses under positive biases.

• Journal of Sericultural and Entomological Science
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• v.13 no.1
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• pp.23-29
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• 1971

As a result of analyzing the change of material substance of all sorts biochemically and comparing the control with ${\gamma}$-ray irradiation (800${\gamma}$, 40 Min), incubating the silkworm eggs (Bombyx mori L.) as the objective in the process of growth of embyro shortly before hatching, the following conclusion has been found. 1. Ascorbic acid has shown the maximum increase of 319 r/g in the Byong B embyro stage and in other words it has increased during the period of vigorous metabolism of the materials in eggs but it has decreased before hatching after that period. 2. Triglyceride has shown the increase of 27.54 mg/g in the Byong A stage, the early period of incubation and in other words it has increased in the period of activation of cells in eggs but it has gradually decreased during the growth of embyro after that period. Great change of either total cholesterol or free cholesterol has not been shown from the early period till shortly before hatching. 3. Free fatty acid has shown the minimum decrease of 257.4$\mu$ mole/g in the Byong A stage in which triglyceride increases greatly. On the contrary, it has shown the increase of 1, 020.0$\mu$ mole/g in Ki A stage in which triglyceride decreases. As a whole, the fact that free fatty acid increases according to the growth of embyro in eggs has been found. 4. Glucose has shown the increase of 281.2 mg/g in control during tile Pigment stage and it has shown the increase of 179.6 mg/g in ${\gamma}$-ray irradiation during the same period. The difference in quantity between the former and the latter is due to the fact that the growth of embyro has been influenced by the radio active. Glucose has changed with free fatty acid and phosphorus the other way round. 5. Control organic phosphorus has shewh the increase of 5.23mg/g during the Byong B or Ki A in which organ and tissue in the emhyro has been formed. Organic phosphorus in ${\gamma}$-ray irradiation has shown the increase of 5.73mg/g during Ki B. Inorganic phosphorus has shown only a little change in the control and ${\gamma}$-ray irradiation. The phosphorus in both has shown a little quantity in the ${\gamma}$-ray irradiation in the early period of incubation. After the Ki A embyro, it has increased rapidly and it has increased till the hatching more continually than in control. The about results of the research will be helpful and instructive to the betterment and improvement, breeding and management of animals and plants.