• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.85-90
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• 2021

The gamma irradiation was on to Poly(butylene sebacate-co-terephthalate) (PBSeT), Poly(butylene adipate-co-terephthalate) (PBAT), Poly(lactic acid) (PLA) and casting polypropylene (CPP) at dose levels from 0 to 50 kGy. The properties of gamma irradiated samples were analyzed using DSC, TGA, UTM and FT-IR spectra. The mechanical and thermal properties of PBSeT and PBAT after gamma irradiation were less affected than CPP. The tensile strength and elongation of PBSeT was not affected by gamma irradiation, while these of PBAT, PLA and CPP were significantly decreased at 50 kGy gamma-ray dose. The thermal stability of PBSeT, PBAT, PLA and CPP showed a similar tendency to tensile strength. The glass transition temperature(T_g) and melting temperature(T_m) of PBSeT and PBAT were not altered by increasing gamma-ray dose, while these of PLA and CPP decreased. The chemical composition of all samples was not modified by gamma irradiation, and it was confirmed by FT-IR spectra. Based on mechanical and thermal stability studies of gamma irradiation on bioplastics, tested biodegradable packaging materials showed a potential to be used in sterilization process up to 35 kGy.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.58-61
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• 2000

This study was conducted to determine the effect of low dose ${\gamma}-ray$ on the germination rate and physiology of germinative seeds of welsh onion ( Allicm fistulosum L. cv. Sukchangwoidae ) and spinach ( Spinacia oleracea L. cv. Chungrok ). The germination rate of irradiation group was much higher than that of the control. Especially it was noticeably higher in 1 or 2 Gy irradiation groups in the sowing spinach seeds on paper towel. On the welsh onion, the germination rate of the 1 Gy irradiation group increased by 17% compared to that of the control. Ion leakage from seeds irradiated with low dose of ${\gamma}-ray$ was decreased compared to that from the control especially at the early stage of incubation when examined by means of electric conductance. This tendency was confirmed in seeds of welsh onion and spinach. Starch hydrolysis was stimulated by ${\gamma}-ray$ irradiation in welsh onion. Furthermore ${\gamma}-ray$ irradiation was beneficial to keeping the vitality of seeds as determined through decarboxylation of glutamic acid.

• Korean Journal of Medicinal Crop Science
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• v.26 no.2
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• pp.127-133
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• 2018

Background: The demand of recycling renewable agricultural by-products is increasing. Radiation breeding is a method used to improve saccharification efficiency. Thus, we investigated the effect of gamma ray irradiation on the pretreatment and enzymatic hydrolysis of the stalks of Senna tora, an important medicinal plants. Methods and Results: S. tora seeds were irradiated with gamma ray at doses of 100, 200, 300, and 400 Gy. In the pretreated biomass, glucan and lignin content were higher in the M1 ($1^{st}$ generations of irradiation) S. tora stalks than in the M2 ($2^{nd}$ generations of irradiation) stalks, this can be explained by the higher degradation rate in M1. After oxalic acid pretreatment, the concentration of total phenolic compounds (TPCs) in the hydrolysate increased in the gamma ray treated seeds. The highest relative increase rate in crystallinity in the pretreated biomass was observed in M1-400 Gy and M2-100 Gy. The cellulose conversion rate was higher in M1 than in M2, except for 200 Gy. Conclusions: Gamma ray irradiation at an appropriate dose can be used to improve the efficiency of pretreatment and enzymatic hydrolysis, thereby increasing biomass availability.

• 전기의세계
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• v.18 no.2
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• pp.15-20
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• 1969

The main focus of this paper is on the study of the .gamma. ray irradiation effect upon the electrical properties of a B-kind insulator which is one of the inorganic insulators. The mica is so typical of the B kind insulators as to be selected for a sample. DC, AC, and Impulse voltage is applied to the variable .gamma. ray irradiated dose samples with the constant time duration and the time variable samples with the .gamma. ray irradiated dose. The dielectric breakdown voltage and dielectric constant are measured from the samples and we get the experimental data that the dielectric breakown voltage variations are relatively large, but the dielectric constants are almost constant. The above conclusion is useful for the selection and application of the inorganic insulators under the irradiation effects, and we expect that the conclusion can apply to not only B-kind insulators but also the inorganic insulators.

• Journal of the Korean Chemical Society
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• v.12 no.2
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• pp.55-60
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• 1968

Chlorination of aromatic derivatives under UV light and ${\gamma}$-ray irradiation was studied. Ethyl ${\alpha} ,{\beta} -dichloro-{\beta}$-phenyl propionate gave the p-chlorophenyl derivatives when chlorination was done under UV light. The same type of the product was obtained in the reaction where the mole ratio of the ester and chlorine was 1 to 2 and the chlorination was done under ${\gamma}$-ray irradiation. When the mole ratio of the ester and chlorine was 1 to 8, the chlorination reaction under ${\gamma}$-ray irradiation gave a poly-chlorinated derivatives which was identified as a side chain chlorinated p-chlorophenyl derivatives. Ethyl ${\alpha} ,{\beta} -dichloro-{\beta}$-(p-chlorophenyl) propionate gave the same type of the side chain chlorinated p-chloro derivatives by the chlorination under ${\gamma}$-ray irradiation, whereas ethyl ${\alpha} ,{\beta} -dichloro-{\beta}$-(o-chlorophenyl) derivatives gave o,p-dichlorophenyl derivatives. The identifications of the products were based on a radio thin layer chromatography and activation analysis of chlorine contents of product. The chlorination reaction was discussed in regards to the effect of phenyl substituents to the formation of reaction product and the procedures were described.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1078-1082
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• 2019

Poly-${\gamma}$-glutamate (${\gamma}$-PGA) has various applications due to its desirable characteristics in terms of safety and biodegradability. Previous studies have been conducted on ${\gamma}$-PGA hydrogels produced by ${\gamma}$-ray irradiation, but these hydrogels have proved unstable in solutions. This study was conducted to enable the ${\gamma}$-PGA hydrogel to maintain a stable form in solutions. The ${\gamma}$-PGA mixture for UV-irradiation was prepared with a cross-linker (N,N,N-trimethyl-3-[(2-methylacryloyl)amino]propan-1-aminium). Both ${\gamma}$-PGA hydrogels' characteristics, including stability in solutions, were examined. The UV-irradiated ${\gamma}$-PGA hydrogel maintained a stable form during the nine weeks of the study, but the ${\gamma}$-ray irradiated hydrogel dissolved after one week.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.65-68
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• 2006

In this study, the extent of plasmid DNA damage was observed according to concentration of BSH(Boron Sulfhydryl Hydride) and irradiation doses of neutron and ${\gamma}$-ray. The plasmid used was both pBR 322 (2870 bp) and ${\Phi}X174$ RF(5386 bp) DNA. Plasmid DNA damage by irradiation in the presence of BSH was analyzed by agarose gel electrophoresis. In the neutron experiment, DNA damage of both plasmid DNAs was increased according to increasing the concentration of BSH and neutron doses. But in the ${\gamma}$-ray experiment, there appeared no dose dependency as compared to the neutron experiment. The extent of the plasmid DNA damage in the presence of BSH was somewhat different according to irradiation by neutron or ${\gamma}$-ray.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.373-381
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• 2012

Antibiotics have been issued recently in water environments because of potential impacts on ecosystem and public health. This study was aimed to investigating the degradation of antibiotics such as tetracycline, lincomycin, sulfamethazine and cephradine using gamma ray irradiation. And the toxicity before and after irradiation on antibiotics was tested in order to examine the aquatic eco-risk assessment by aquatic organisms. In addition, comparing tests on toxicity for gamma ray and UV irradiated antibiotics was conducted. Four different antibiotics were prepared by concentration of 30 mg/L with demi-water respectively. The absorption dose of gamma ray was ranged from 0.2 to 2 kGy. The concentration of four antibiotics was gradually decreased corresponding to the increase of the absorption dose. A method for toxicity assessment using Pseudokirchneriella subcapitata was evaluated to the most acceptable compared with methods by Daphnia magna and Microtox$^{(R)}$ in terms of sensibility. It showed that the reduction of toxicity on antibiotics treated by gamma ray was superior comparing to the test results obtained from UV treatment. By-products from antibiotics treated by gamma ray were easily decomposed by microorganism and their toxicity was also evaluated to low.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.51-54
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• 2013

Chitosan is a useful natural polymer material in many application fields such as biomaterials, water-treatment, agriculture, medication, and food science. However, the poor solubility limits its application. In this study, the effects of radiation on chitosan were investigated using gamma ray and electron beam irradiation. The chemical structure and molecular weight analysis show similar degradation effects of chitosan powder in both gamma ray and electron beam irradiation. However, the radiation irradiated chitosan in $H_2O$ has a lower molecular weight, since the hydroxyl radicals attack the glycosidic bonds. This effect is more clearly shown in the electron beam irradiation results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.193-199
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• 2015

We observed that the growth and physiological change in Haliotis discus discus by low-dose irradiation with gamma ray.Irradiation with gamma ray was undertaken by using the low-level irradiation facility ($^{60}CO$) in cooperation with the Institute of Nuclear Science and Technology at Jeju National University. The parent abalones were attached one by one and then fixed by using the rubber band to the front side of the fabricated case for irradiation with gamma ray. The experimental plots of irradiation with gamma ray were set as 10, 15, 20 and 25 Gy and the 25 female abalones and 10 male abalones were utilized for each experimental plot. The sperms and eggs were fertilized by setting an interval for each dose to prevent mixing with other experimental plots when fertilizing the sperms and eggs for each dose of irradiation with gamma ray. As for the fertility, it was confirmed to be 85% the control and 10 Gy groups, whereas it was found to be 80%, 65% and 50% in the 15 Gy, 20 Gy and 25 Gy groups, respectively. As a conclusion, the hatching rate and attachment rate were higher at 10 and 15 Gy than the other experimental plots, and the growth rate was higher at 20 Gy than the other experimental plots. Also the changes in lysozyme activity in accordance with the stress of water temperature were found to have a significant increase in the other experimental plots as compared with the control plot at the end of 0 h. The changes in lysozyme activity have remained constant in all the experimental plots at the end of 12 h. These results allowed us to confirm that lysozyme was undertaking the biodefense action by reacting sensitively to the stress of water temperature in the control experimental plot. As for the other experimental plots, they are believed to avoid the biodefense mechanism due to the high degree of anti-parasite mechanism and anti-viral mechanism. Thus, it is believed that it would be imperative to conduct development and research on breeds that were potent for environmental tolerance by applying the method of irradiation with gamma ray to other marine animals and plants.