• 제목/요약/키워드: radioactivity

검색결과 972건 처리시간 0.025초

흰쥐에서 NG-Monomethyl-L-arginine으로부터 methylamine의 생성 (Formation of methylamine from NG-Monomethyl-L-arginine in Rat)

  • 조영봉;안영곤;최홍순;김춘성
    • 한국산업보건학회지
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    • 제6권1호
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    • pp.138-143
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    • 1996
  • After oral administration of 14C-labelled $N^G$-mono[methyl-14C]-L-arginine into rats, 38.2 % and 14.7 % of the administered radioactivity bad been recovered in the urine and stool during 10 days. In the urine, 59.4 % of the radioactivity was recovered in the first 24-hours and used for the indentification of the formation of methylamine. The strong cation-exchange resin column chromatography showed 6.3 %, 7.4 %, 4.9 %, and 81.5 % of the distributions of radioactivity of the neutral, monomethylamine, basic, and uneluted portions, respectively. The radioactivity of monomethylamine portion reeluted into the column chromatography was 39.5 %. The radioactivities corresponding monomethylamine in the column chromatography, thin-layer chromatography, and thin-layer electrophoresis were 39.5 %, 37.3 %, and 28.8 % of the recovered radioactivity, respectively.

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$^{82}Sr/^{82}Rb$ 발생기의 제조 및 정상인 심근의 양전자 단층촬영상 (Preparation of $^{82}Sr/^{82}Rb$ Generator and Positron Emission Tomographic Image of Normal Volunteer)

  • 정재민;정준기;이동수;곽철은;이경한;이명철;고창순
    • 대한핵의학회지
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    • 제28권3호
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    • pp.326-330
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    • 1994
  • A $^{82}Sr/^{82}Rb$ generator was prepared by loading $^{82}Sr$ to preconditioned tin dioxide column. The generator was eluted by normal saline with flow rate up to 8m1/min, and the eluted radioactivity was monitored by dose calibrator. Radioactivity began to come out at 5ml and reached to peak around 9ml. The total eluted radioactivity increased linearly with flow rate, and the maximum obtained radioactivity was 35mCi at 8m1/min. The $^{82}Rb$ preparation was proven to be free from both strontium radioactivity and pyrogen. The $^{82}Rb$ was injected to normal female volunteer and positron emission tomographic Image of heart was obtained successfully.

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정상 및 손상된 흰쥐 피부에 국소 적용된 $^{125}I-rhEGF$의 체내 이행 (Body Distribution of $^{125}I-rhEGF$ Across Normal and Damaged Rat Skins)

  • 이정욱;정석재;이민화;심창구
    • 약학회지
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    • 제41권6호
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    • pp.730-736
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    • 1997
  • Distribution of radioactivity in the skin tissues, subcutaneous tissues, blood and body organs was examined following topical application of $^{125}I-rhEGF$(0.4 ${\mu}Ci$), in the form of a Pluronic F-127 gel, on the normal and damaged (burned and stripped) skins of SD male rats. The radioactivity in the skin tissues and subcutaneous tissues was 3-5 times higher for the damaged skins than for the normal skin. But pretreatment of the skin with rhEGF (1${\mu}g$)) twice at 24 hr dose intervals affected the distribution of the radioactivity yielding the order of burned skin> stripped skin=normal skin. The decrease for the stripped skin by the pretreatment might be related either to the pathophysiological change of the skin or to the down regulation of the EGF receptor. Liver showed the highest radioactivity in amount following single and multiple administration of the drug to the normal and damaged skins. But,in concentration, the kidney and stomach showed higher value than the liver which is consistent with that kidney is a major eliminating organ of EGF and that EGF exerts its pharmacological effect specifically for the stomach.

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Oxidative Degradation of a Drug during the Course of Diffusion Across the Skin

  • Choi, Hoo-Kyun
    • Archives of Pharmacal Research
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    • 제20권6호
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    • pp.637-642
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    • 1997
  • Degradation of a compound with a hydroxyl group during the course of its diffusion across the skin was investigated. Based on the experimental findings of ashortened retention time of a degradant peak from post-diffusion samples and from the ability to evaporate radioactivity from such samples, it seems that during diffusion the parent compound degrades into a more hydrophilic product which is then oxidized. A tritium label at the carbon with a hydroxyl group was released as a tritiated water. When the post-diffusion samples were left open to the air allowing evaporation of water, there was a corresponding decrease in radioactivity of such samples. There was a linear relationship between the time left open and the fraction of radioactivity lost. When such samples were fractionated by HPLC, and then had their radioactivities measured by scintillation counting, two peaks wre identified. The first peak, which may be attributable to tritiated water, was eluted at the same retention time as the solvent front. The second peak eluted at the retention time of the parent compound. When the evaporation/loss of radioactivity experiment was repeated using a $^{14}C$-labeled compound there was no significant loss of radioactivity, indicating that the earlier loss with $^{3}H$-labeled compound was related to the formation and loas sof tritiated water.

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Overestimation of Radioactivity Concentration of Difficult-To-Measure Radionuclides in Scaling Factor Methodology

  • Park, Junghwan;Kim, Tae-Hyeong;Lee, Jeongmook;Kim, Junhyuck;Kim, Jong-Yun;Lim, Sang Ho
    • 방사성폐기물학회지
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    • 제19권3호
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    • pp.367-386
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    • 2021
  • The overestimation and underestimation of the radioactivity concentration of difficult-to-measure radionuclides can occur during the implementation of the scaling factor (SF) method because of the uncertainties associated with sampling, radiochemical analysis, and application of SFs. Strict regulations ensure that the SF method as an indirect method does not underestimate the radioactivity of nuclear wastes; however, there are no clear regulatory guidelines regarding the overestimation. This has been leading to the misuse of the SF methodology by stakeholders such as waste disposal licensees and regulatory bodies. Previous studies have reported instances of overestimation in statistical implementation of the SF methodology. The analysis of the two most popular linear models of the SF methodology showed that severe overestimation may occur and radioactivity concentration data must be dealt with care. Since one major source of overestimation is the use of minimum detectable activity (MDA) values as true activity values, a comparative study of instrumental techniques that could reduce the MDAs was also conducted. Thermal ionization mass spectrometry was recommended as a suitable candidate for the trace level analysis of long-lived beta-emitters such as iodine-129. Additionally, the current status of the United States and Korea was reviewed from the perspective of overestimation.

인천지역 근린공원의 토양 방사능 농도 (Soil Radioactivity in Urban Parks of Incheon)

  • 장준수;이상복;백가은;신희철;이경재;이도화;김성철
    • 대한방사선기술학회지:방사선기술과학
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    • 제46권1호
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    • pp.37-42
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    • 2023
  • Most of research on environmental radioactivity is conducted in areas near nuclear power plants, so basic data about the distribution of environmental radioactivity in soil in other areas are insufficient. Therefore, in this study, divide into four categories by the land development characteristics of Incheon and the purpose of development, and confirm the stability of the Incheon through soil sample collection and gamma-ray analysis based on 40K, 137Cs and 226Ra (214Pb, 214Bi). The spectrum obtained by measuring for 80,000 seconds by using the HPGe detector was analyzed by Genie 2000 program. Soil radioactivity concentrations in urban parks of Incheon area are generally within a safe range compared to the results of the Nuclear safety and security commission. However, as 137Cs was detected in one park, which will require continuous monitoring.

고리1호기 가동이력을 고려한 손상 배플포머볼트 방사화 계산 (Radioactivity Calculation Considering Kori Unit 1 Operation History for the Defected Baffle Former Bolts)

  • 맹영재;이현철;이명호;황성식;오승진;장윤석
    • 한국압력기기공학회 논문집
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    • 제19권1호
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    • pp.20-26
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    • 2023
  • The defected baffle former bolts of Kori unit 1 were withdrawn to analyze the cause of damage and gamma-ray measurement is being scheduled. Prior to that, in order to calculate the specific radioactivity value of the baffle former bolt, a radioactivity calculation method considering the actual operation history of the nuclear power plant is introduced and the calculation results are shown. In particular, the radioactivity calculation method considering the operation history is obtained by defining the monthly contribution factor from the actual monthly operation history. As a result, the results considering operation history are 16-28% lower than the general radioactivity calculation results. These results can contribute to establish a reasonable but economical strategy when planning nuclear power plant decommissioning.

환경방사능 데이터 분석을 위한 실시간 환경 감시차량 관제 시스템 구축 (Development of Geographical Information System for the Realtime Environmental Radioactivity Monitoring)

  • 손호웅;김인현;이윤;김영우
    • 지구물리
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    • 제7권1호
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    • pp.61-72
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    • 2004
  • 실시간으로 수집된 환경방사능 데이터 및 차량위치정보를 무선통신망을 통해 전송 받아 지도 상에 표출하고 핵종별 수집시간대별 분석 및 차량 위치별 수집데이터 분석 등의 통계분석기능과 결과물의 문서출력기능을 지원하고 다수의 감시차량 관제 및 관리가 가능한 서버 클라이언트 환경의 환경방사능 감시 차량관제 시스템을 개발하였다

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Soil and Coal Radioactivity around Zuunmod Town of Mongolia

  • Erkhembayar, Ts.;Norov, N.;Khuukhenkhuu, G.;Oyunchimeg, Ts.
    • 한국의학물리학회:학술대회논문집
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    • 한국의학물리학회 2002년도 Proceedings
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    • pp.501-505
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    • 2002
  • The specific radioactivity concentrations of $\^$238/U, $\^$232/Th, $\^$40/K were measured in soil samples around Zuunmod town of Mongolia using HP-Ge gamma-spectrometer. Also the specific radioactivity concentrations of above elements were measured in coal and ash samples which were collected from the Central steam heating in Zuunmod town. It was determined the effective equivalent dose.

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Characteristics of Reduced Metal from Spent Oxide Fuel by Lithium

  • Kim Ik-Soo;Seo Chung-Seok;Shin Hee-Sung;Hwang Yong-Soo;Park Seong-Won
    • Nuclear Engineering and Technology
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    • 제35권4호
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    • pp.309-317
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    • 2003
  • The mass balance of the unit processes of the Advanced spent fuel Conditioning Process was calculated to obtain basic information. Based on this mass balance, the changes in decay heat and radioactivity of the spent fuel due to the metallization in the high temperature molten salt system were estimated. The decay heat and the radioactivity were calculated by using the ORIGEN2 computer code, and the result showed that the decay heat and the radioactivity of the metallized spent fuel ingot were $24.27\%\;and\;24.24\%$, respectively, compared to those of oxide spent fuel.