• Title/Summary/Keyword: Half Life

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Determination of Self-Disposal date by the Analysis of Radioactive Waste Contamination for 1131I Therapy Ward (131I 치료입원실 폐기물 방사능 오염도 분석 및 자체처분가능일자 산출)

  • Kim, Gi-sub;Jung, Haijo;Park, Min-seok;Jeon, Gjin-seong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.17 no.1
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    • pp.3-6
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    • 2013
  • Purpose: The treatment of thyroid cancer patients was continuously increased. According to the increment of thyroid cancer patients, the establishment of iodine therapy site was also increased in each hospital. This treatment involves the administration of radioactive iodine, which will be given in the form of a capsule. Therefore, protections and managements for radioactive source pollution and radiation exposure should be necessary for radiation safety. Among the many problems, the problem of disposing the radioactive wastes was occurred. In this study, The date for self-disposal for radioactive wastes, which were contaminated in clothes, bedclothes and trash, were calculated. Materials and Methods: The number of iodine therapy ward was 15 in Korea Institute of Radiological Medical and Sciences. Recently, 8 therapy wards were operated for iodine therapy patients and others were on standby for emergency treatment ward of any radiation accidents. Radioactive wastes, which were occurred in therapy ward, were clothes, bedclothes, bath cover for patients washing water and food and drink which was leftover by patients. Each sample was hold into the marinelli beaker (clothes, bedclothes, bath covers) and 90 ml beaker (food, drink, and washing water). The activities of collected samples were measured by HpGe MCA device (Multi Channel Analysis, CANBERRA, USA) Results: The storage period for the each kind of radioactive wastes was calculated by equation of storage periods based on the measurement outcomes. The average storage period was 60 days for the case of clothes, and the maximum storage period was 93 days for patient bottoms. The average storage period and the maximum storage period for the trash were 69 days and 97 days, respectively. The leftover foods and drinks had short storage period (the average storage period was 25 days and maximum storage period was 39 days), compared with other wastes. Conclusion: The proper storage period for disposing the radioactive waste (clothes, bedclothes and bath cover) was 100 days by the regulation on self-disposal of radioactive waste. In addition, the storage period for disposing the liquid radioactive waste was 120 days. The current regulation for radioactive waste self-disposing was not suitable for the circumstances of each radioactive therapy facility. Therefore, it was necessary to reduce the leftover food and drinks by adequate table setting for patients, and improve the process and regulation for disposing the short-half life radioactive wastes.

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Numerical Fatigue Life Prediction of IGBT Module for Electronic Locomotive (수치해석을 이용한 전동차용 IGBT 모듈의 피로 수명 예측)

  • Kwon, Oh Young;Jang, Young Moon;Lee, Young-ho;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.1
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    • pp.103-111
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    • 2017
  • In this study, the thermomechanical stress and fatigue analysis of a high voltage and high current (3,300 V/1200 A) insulated gate bipolar transistor (IGBT) module used for electric locomotive applications were performed under thermal cycling condition. Especially, the reliability of the copper wire and the ribbon wire were compared with that of the conventional aluminum wire. The copper wire showed three times higher stress than the aluminum wire. The ribbon type wire showed a higher stress than the circular type wire, and the copper ribbon wire showed the highest stress. The fatigue analysis results of the chip solder connecting the chip and the direct bond copper (DBC) indicated that the crack of the solder mainly occurred at the outer edge of the solder. In case of the circular wire, cracking of the solder occurred at 35,000 thermal cycles, and the crack area in the copper wire was larger than that of the aluminum wire. On the other hand, when the ribbon wire was used, the crack area was smaller than that of the circular wire. In case of the solder existing between DBC and base plate, the crack growth rate was similar regardless of the material and shape of the wire. However, cracking occurred earlier than chip solder, and more than half of the solder was failed at 40,000 cycles. Therefore, it is expected that the reliability of the solder between DBC and base plate would be worse than the chip solder.

In vitro and in vivo Antibacterial Activities and Pharmacokinetics of 8-Fluorociprofloxacin and Ciprofloxacin (8-Fluorociprofloxacin과 Ciprofloxacin의 시험관내 및 생체내 항균효과와 약물동태의 비교)

  • 최경업;정용환;김제학
    • YAKHAK HOEJI
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    • v.37 no.3
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    • pp.235-242
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    • 1993
  • 8-Fluorociprofloxacin(8-FCP) is an investigational quinolone derivative that is substituted with fluorine at the C-8 position of ciprofloxacin(CP). It was found that the in vitro activity of 8-FCP against Gram(+) bacteria was more potent that of CP, but the opposite against Gram(-) bacteria was true. However, 8-FCP showed better in vivo efficacy than CP against representative Gram(-) organisms, E. coli and K pneumoniae. In an attempt to seek for factors causing this discrepancy in the antibacterial activities, a comparative pharmacokinetic study of 8-FCP and CP was conducted in mice and rats treated either intravenously or orally at a single dose of 30 mg/kg. The pharmacokinetic parameters in mice were as follows; the mean peak serum concentrations(C$_{max}$) following i.v. and oral doses were 12.4 and 5.3 $\mu\textrm{g}$/ml for 8-FCP, and 9.5 and 2.5 $\mu\textrm{g}$/ml for CP, respectively. The terminal half-life(t$_{1/2\beta}$) was 72.9 min for 8-FCP, and 98.2 min for CP, and the oral bioavailability(F) was 89.9% for 8-FCP, and 50.5% for CP. In rats, the mean ($\pm$SD) $C_{max}$ after i.v. administration were 11.6$\pm$1.6 $\mu\textrm{g}$/ml for 8-FCP, and 10.2$\pm$1.3 $\mu\textrm{g}$/ml for CP, whereas oral administration produced $C_{max}$ of 5.9$\pm$1.8 $\mu\textrm{g}$/ml for 8-FCP and 1.1$\pm$0.9 $\mu\textrm{g}$/ml for CP, respectively. The t$_{1/2\beta}$ was 67.9$\pm$8.4 min for 8-FCP, and 76.4$\pm$7.2 min for CP. The F was 88.6$\pm$6.3% for 8-FCP, and 40.7$\pm$6.5% for CP. Marked differences were observed between the two quinolones in the $C_{max}$ and the area under the concentration-time curve obtained after oral administration in mice and rats. The extent of 8-FCP absorption in both mice and rats was approximately 2-fold higher than that of CP, suggesting that the fluorine atom attached to C-8 plays an important role in facilitating oral absorption from the gastrointestinal tract.

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Thermal Decomposition of A New Insecticide KH-502 [O, O-Diethyl O-(1-phenyl -3-trifluoromethy-5-pyrazoyl) thiophosphoric acid ester] (신규(新規) 살충제(殺蟲劑)인 O, O, O-Diethyl-O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester의 열(熱)에 의한 분해성(分解性))

  • Cho, Boo-Yeon;Han, Dae-Sung
    • Korean Journal of Environmental Agriculture
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    • v.11 no.3
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    • pp.225-234
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    • 1992
  • Thermal decomposition was conducted to investigate the influence of the various factors on stability of a new insecticide, [O, O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester : KH-502], in view of those informations applicable for industrial exploitation. In the thermal decomposition experiment, KH-502 was, after mixing with Fe, Cu and adjustment of moisture and pH conditions, subjected to three temperatures, 25, 50, and $100^{\circ}C$. Results for stability, and degradation pattern of KH-502 from the above experiment can be summarized as follows: 1. Main products of the thermal decomposition when this was conducted in the closed system were identified as following five compounds:O, O, O-Triethylthiophosphoric acid(TEPA), 1-Phenyl-3-trifluoromethyl-5-ethoxypyrazole(PTMEP), 1-Phenyl-2-ethyl-3-trifluoromethyl-5-hydroxypyrazole(PETMHP), O, O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphoric acid ester(KH-502 oxo form), O, S-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phospho rothiolate(S-ethyl KH-502). However, compounds such as oxo form and S-ethyl KH-502 were not identified when the thermal decomposition was proceeded in the open system. 2. KH-502 was stable at 25 and 50$^{\circ}C$, but it was decomposed at 100$^{\circ}C$ following the first-order kinetics at the early stages of decomposition. 3. Rate constants for the thermal decomposition of KH-502 at 100$^{\circ}C$ were in the orders of Cu powder addition 0.344>Cu plate addition 0.21>moisture addition 0.05>closed system=open system=iron addition=pH 5.5 adjustment 0.04>pH 8.5 adjustment 0.027 day$^{-1}$, representing KH-502 was decomposed fast at Cu powder treatment and slow at pH 8.5 adjustment. 4. Half-life for the thermal decomposition of KH-502 at 100$^{\circ}C$ was in the orders of Cu powder addition 2.02

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Residue Analysis to Establish an Index for the Safety Use of Propineb (Propineb의 안전사용(安全使用) 기준(基準) 설정(設定)을 위한 잔류분석(殘留分析))

  • Choi, Won-Seog;Yang, Jae-Eui;Han, Dae-Sung
    • Korean Journal of Environmental Agriculture
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    • v.11 no.3
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    • pp.209-214
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    • 1992
  • Residue of Propineb in Sesame(Sesamum indicum L.) seed was determined to establish an index for the safety use of Propineb to Sesame. Evaluation was made on residual concentration of Propineb in Sesame seed as a function of application frequency and date when the mixed formulations of Propineb(56%), protectant fungicide, and Oxadixyl(8%), contact fungicide, were sprayed into Sesame leaves. Level of Propineb treatment was $0.028g/m^2$ with various combinations of application time from three to sixty days before harvest. Results are summarized as followings. 1. Recovery percentages of Propineb from Sesame seed were ranged from 84 to 96, and the minimum detectable limit of Propineb with the method employed in this experiment was 0.03mg/kg. 2. Residues of Propineb in Sesame seed were in the ranges of 0.14 to 1.38mg/kg, varying with frequency and date of Propineb application. 3. Residues of Propineb increased as increasing application frequency of Propineb or as being application date closer to harvest time. 4. Residue of Propineb in Sesame seed was decreased with time, showing to be fitted to the first-order kinetics. 5. Residues of Propineb in Sesame seen were, irresepective of treatments, lower than 2mg/kg, the Maximum Residue Limit(MRL) established by FAO/WHO. 6. Half-life of Propineb determined in this experiment was ranged from 12 to 16 days.

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The Study on the Dilution Time of Radioactive Tracer in Estradiol Measurement (방사성 요오드 치료 후, 퇴원 선량 측정에 있어 각국의 기준 및 권고 비교)

  • Lee, Seung Jae;Seo, Soo Hyun;Lee, Sung Ha;Park, Yong Sung;Oh, Ki Baek;Kim, Jae Sam
    • The Korean Journal of Nuclear Medicine Technology
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    • v.21 no.2
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    • pp.49-54
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    • 2017
  • Purpose The high-dose administration of I-131 has been standing for the basic therapy method of thyroid cancer. In korea, it is not necessary for patients to be hospitalized if the administration dose are under 1.2 GBq. However, if the dose are over 1.2 GBq, the patients should be stay in special ward with radiation shield. In such cases, the radioactivity level upon release should be under a dose of $70{\mu}Sv/hr$ at a distance of approx. 1m. This regulation bring the patients to stay for about 2 to 3 days in ward before the release. Materials and Methods Using the inpatients' release data of severance hospital, an inpatient-days were retrospectively calculated and compared with practical data and estimate the inpatient-days with the conditions of korea ($70{\mu}Sv/hr$), Japan ($30{\mu}Sv/hr$), germany ($3.5{\mu}Sv/hr$ at a distance of approx. 2 m), and other european countries. Results When a effective half-life of 15.4 was used, the expected inpatient-days were calculated as 2.15 days in the condition of Japanese regulation and 1.37 days in the condition of korean regulation. The practical inpatient-days of patients in Severance hospital were 1.32 days. Conclusion As ICRP 94 has been mentioned that the release of patients administrated with I-131 for the therapy should be carefully considered because each patients has different thyroid uptake rate and their conditions with family members after the release from the ward. Nonetheless, efforts to bring more aquate data which is for getting closer to the practical data should be continuously studied.

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Eradication Effect of Penicillin Administration on the Asymptomatic Infections of Group A Streptococci (A군 연쇄구균 무증상 감염자에서 페니실린 투여 후 세균제거 효과에 대한 조사)

  • Jung, Hyun-Ju;Kim, Seon-Ju
    • Pediatric Infection and Vaccine
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    • v.5 no.2
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    • pp.215-220
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    • 1998
  • Purpose : Asymptomatic infections with positive throat culture for group A beta-hemolytic streptococci(GABHS) and high antistreptolysin O(ASO) concentration may lead to sequelae such as rheumatic fever or acute poststreptococcal glomerulonephritis. Children with asymptomatic infections were treated with oral penicillin V to evaluate the effectiveness of penicillin treatment on the asymptomatic infections. Methods : Throat culture and ASO concentration analysis were performed against healthy elementary school children. Thirty-six children with positive throat culture for GABHS and ASO concentrations of 400 IU/mL or more were divided into two groups. Twenty-two children were treated with oral penicillin V for 10 days, and the others were not treated. Eradication rate of GABHS and the change of ASO concentration between the two groups were compared after one month later. Results : Eradication rates of GABHS between treated and untreated children were 91%(20/22) and 50%(7/14) respectively(P<0.05). Children showing elevation of ASO levels more than 100IU/mL were 22%(4/18) in the treated group and 30%(3/10) in the untreated group, while children showing a decrease of more than 200IU/mL in the ASO level were 44%(8/18) and 40%(4/10) respectively. Conclusion : We confirmed the validity of penicillin treatment, because when we treated the asymptomatic children with penicillin V, the GABHS was eradicated effectively. But there was no significant difference of decrease in the ASO levels between the two groups due to long half-life of ASO or poor compliance. Treatment failure was 22% in terms of elevated ASO levels after penicillin treatment.

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A case of fused thoracic vertebrae, and lumbar vertebrae, sacrum and ilium of African elephant (Loxodonta africana) were fused one another partially (아프리카코끼리(Loxodonta africana)의 흉추골유합과 요추골, 천골 및 장골이 유합된 1례)

  • Kim, Chong-sup;Won, Chung-kil;Cho, Gyu-hen;Cho, Kyu-woan;Park, Joong-suk;Rho, Gyu-jin
    • Korean Journal of Veterinary Research
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    • v.42 no.2
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    • pp.131-136
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    • 2002
  • The vertebrae of female African elephant (Loxodonta africana) of twenty-eight years old were observed macroscopically. The result was summarized as follows; the vertebral formula of African elephant was $C_7$ $T_{21}$ $L_3$ $S_4$ $Cd_{21}$. The total length of the vertebral column removed intervertebreal disks was 353 cm. The length of each segment of vertebral column was 44 cm in cervical, 142 cm in thoracic, 21 cm in lumbar, 27 cm in sacral and 119 cm in caudal vertebrae. The 17th and 18th thoracic vertebrae (T) were partially fused each other in four parts: the transverse processes of 17th and 18th T, caudal articular process of 17th T and cranial articular process of 18th T, left mammilary process of 18th T and left transverse process of 17th T, and vertebral arch of 17th and 18th T, respectively. Others partial fusions also observed among the third luwbar, sacrum and ilium. These were in between transverse process of third lumbar vertebra and cranial parts of wing of sacrum, lateral part of sacrum and tuber sacrale, respectively. The sternum was consisted of three pieces; one is a part of anterior prestemum, two is the part from caudal demifacet at second facet to cranial demifacet at third facet in middle mesosternum, which is divided vertically into an half at second and third facets, respectively, and the last is the part between caudal demifacet of third facet in middle mesosternum and the posterior xiphisternum. There are 21 pairs of ribs, six sternal, ten asternal ribs and the last five being floating ribs.

Population Dynamics of Smoothshell Shrimp, Parapenaeopsis tenella from the Coastal Area of Geomun-do, Korea (한국 거문도 인근해역의 만새우, Parapenaeopsis tenella의 개체군 동태)

  • Oh, Taek-Yun;Cha, Hyung-Kee;Choi, Jung-Hwa
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.1
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    • pp.9-16
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    • 2004
  • Parapenaeopsis tenella occurs widely on the south and west coasts of Korea. Sex ratio showed seasonal variations, with a mean value of 48.6% for the females. The species produces one cohort a year, with the ovaries ripening from July to August. Insemination took place from July to August, as more than half of the females sampled in the study over 14 mm CL were inseminated. Gonadosomatic index (GSI) reached the maximum between July and August. The smallest mature female was 11 mm CL. Size at 50% sexual maturity ($CL_{50}$), determined from both mature females and inseminated females, was 12.53 mm and 12.28 mm CL, respectively. The life span of females appeared to be 14-15 months according to size frequency distributions, while that of the male was 13-14 months. Population growth was estimated by the modified von Bertalanffy growth function incorporating seasonal variation in growth. Based on the growth parameters (K = 1.22 $yr^{-1}$ and $L_{\infty}$ = 21.99 mm CL for females, and K = 2.00 $yr^{-1}$ and $L_{\infty}$ = 15.00 mm CL for males) growth curves showed that females grew faster and reached a larger size at age than males.

A Study on the Recognition of the Students of Technical High School on Fire Safety : Focusing on Skills Student in the Seoul Metropolis (공업계 고등학교 학생의 소방안전의식에 관한 연구 - 서울지역의 기능반 학생을 중심으로 -)

  • Cho, Seung-Ho;Choi, Don-Mook
    • Fire Science and Engineering
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    • v.20 no.3 s.63
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    • pp.107-112
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    • 2006
  • The purpose of this study is to help the education of fire safety of technical high schools through the investigation of skills club students's recognition on fire safety in Seoul city. To achieve the purpose, 56 skills students who going to skills competition were surveyed for 3days from Jun. 19 to 21, 2006. The Results of this study are as follows ; First, a large numbers of students in technical high school placed low value on the importance of safety in life, and fire safety was very important, however, lower than structural safety. Second, the education of fire safety was arranged by school authorities, carried out only by the half of these school. It was necessary that the specific education of fire safety for major and skills competition was hosted by a department. Third, it was necessary that the system all accidents were certainly reported by the related student and the method prevented a recurrence. 4th, the field of fire safety in Industrial Introduction subject of national curriculum was satisfied by students. And if this subject revised, students wanted to extend the contents of fire safety and to orient to practical technique.