• Title/Summary/Keyword: $\gamma$-Irradiation

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Habituation of Escherichia coli O157:H7 in Alkali and Susceptibility of Causative Agents (알칼리조건에서 Escherichia coli 0157:H7의 적응 및 항균요법제에 대한 감수성)

  • 배종호
    • The Korean Journal of Food And Nutrition
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    • v.12 no.6
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    • pp.564-568
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    • 1999
  • Habituation to alkali condition and susceptibility to antimicrobial agents were investigated to determine methods t inactivation Escherichia coli O157:H7 associated with food poisoning. The investigation showed that Escherichia coli O157:H7growth at pH 9.0 The susceptibilities of Escherichia coli O157:H7 to 13 drugs examined were found highest in regad to saicin and ceftriaxone and lowest in regard to erythromycin and josamycin. No significant changes in minimal inhibitory concen-tration(MIC) values of bactericidal effect was found when saicin and ceftriaxone were irradiated with doses of 5-100KGy.

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Brachytherapy for Head and Neck Cancer (두경부암의 근접방사선 치료)

  • Yoo Seong-Yul
    • Korean Journal of Head & Neck Oncology
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    • v.7 no.1
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    • pp.3-9
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    • 1991
  • Brachytherapy is a method of radiotherapy in advantage to achieve better local control with minimum radiation toxicity in comparison with external irradiation because radiation dose is distributed according to the inverse square low of gamma-ray emitted from the implanted sources. The main characteristics of brachytherapy are delivering of higher dose to target volume shortening of total treatment period and sparing of normal tissue. Recent development of iridium ribbons for low dose rate implant provides improvement of technology of brachytherapy in terms of safety and efficiency. High dose rate method. on the other hand, is effective to avoid unnecessary expoure of medical personnel.

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Morphological Observation and Silicate Content of Short Culm Mutants in Rice (수도두간변이계통의 형태 및 규산함량에 관한 연구)

  • 한창열
    • Journal of Plant Biology
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    • v.14 no.3
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    • pp.29-35
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    • 1971
  • Various types of short culm rice mutants were obtained by means of gamma-ray irradiation. In the present paper morphological observation and analysis of silicate content of the mutants are reported. 1. Short culm type had more useful characters than bushy and dwarf types. 2. In short culm and bushy types the number of nodes both above and under ground was similar to the mother varieties, while in dwarf type it decreased. 3. In short culm types the variation of length of above-ground culm and internodes tended to vary relattive to the mother varieties. 4. Positive correlation was found between culm length and the first and fourth internode length in short culm type. 5. Silicate content increased in short culm type-the increment being variety specific.

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The Experimental Study of Co$^{60)$ Irradiaton Effect on Radiation Damage of A-Kind Insulator ($Co^{60}$ 조사에 대한 A 급 절연채로의 방사선 손상에 관한 연구)

  • 지철근;김병수
    • 전기의세계
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    • v.20 no.3
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    • pp.27-31
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    • 1971
  • The main focus of this paper is on the study of the radiation effect upon the electrical property of a A-Kind insulator which is one of the organic insulators. The varnished cloth is so typical of the A-Kind insulators as to be selected for a sample. AC and Impluse voltage is applied to the variable Gamma ray irradiated dose samples with the constant time duration and the dielectric breakdown voltage are measured from the sample. The experimental data of the dielectric breakdown voltage are considerably decreased. The above conclusion is useful for the selection and application of the orgainc insulators under the irradiation effects.

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Radioprotective Effects of Ginseng Proteins (인삼단백질의 방사선 방어작용)

  • 김춘미;한규선
    • YAKHAK HOEJI
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    • v.29 no.5
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    • pp.246-252
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    • 1985
  • Ginseng proteins were isolated and partially purified to obtain two fractions, namely GI and GII. Radioprotective effects of these fractions were examined on $\gamma$-ray irradiated ICR mice by observing 30-day survival rates after irradiation. Also investigated were the effects of GI fraction on the recovery of radiation damage. As the results, the GI fraction showed strong protection against radiation indicated by the increment of 30-day survival rates, while the GII fraction did not. The GI fraction enhanced the recovery of body and splenic weights and increased the amount of DNA in liver significantly. It also helped to recover the damage done on erythrocytes by increasing the number to normal in short period, however, it had no effect on the recovery of leukocyte counts.

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The Improvements for Fire Retardancy and Radiation Resistance of Chloroprene Rubber (클로로프렌 고무의 난연성 및 내방사선 특성 향상)

  • Kim, Ki-Yup;Lee, Chung;Ryu, Boo-Hyung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.11
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    • pp.1205-1211
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    • 2004
  • This study has investigated radiation degradation of chloroprene rubber in the presence of some fire retardant. Ammonium polyphosphate, aluminium trihydroxide, magnesium hydroxide, calcium carbonate and antimony trioxide were selected as flame retardant. Samples were irradiated using a Co$^{60}$ ${\gamma}$ -ray and ray up to 2000 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, samples were assessed fire retardancy with electrical properties and mechanical properties. Some considerations concerning the effects of the fire retardants added to chloroprene rubber on the radiation and thermal stability of chloroprene rubber are presented. From fire retardancy with electrical and mechanical property measurements, it was found that addition of magnesium hydroxide resulted in maximum fire retardant effect.

A study on radiation degradation of LDPE by using ESR (ESR을 이용한 저밀도 폴리에틸렌의 방사선 열화에 관한 연구)

  • Kim, Ki-Yup;Kim, Jin-Ah;Lee, Chung;Kim, Pyeong-Jong;Ryu, Boo-Hyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07a
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    • pp.473-476
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    • 2004
  • This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated using a $Co^{60}\;\gamma-ray$ and ray up to 800 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, free radical measurement of LDPE has established by electron spin resonance(ESR). Then, each sample was stored for 2 weeks. ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and changed from alkyl, allyl radical to peroxy radical with time.

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