• 제목/요약/키워드: Half Life Time

검색결과 507건 처리시간 0.032초

복숭아의 재배기간 중 살충제 Clothianidin 및 살균제 Fluquinconazole의 생산단계 농약잔류허용기준의 설정 (Establishment of Pre-Harvest Residue Limits (PHRLs) of Insecticide Clothianidin and Fungicide Fluquinconazole on Peaches during Cultivation Period)

  • 박재훈;임종성;윤지영;문혜리;한예훈;이용재;이규승
    • 한국환경농학회지
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    • 제31권3호
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    • pp.271-276
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    • 2012
  • BACKGROUND: It is hard to control the agricultural products exceeding MRL (maximum residue limit) before forwarding. Therefore, NAQS (National Agricultural Products Quality Management Service, South Korea) established PHRL (pre-harvest residue limit) on agricultural products during their cultivation periods. This study was performed to set the PHRLs of peach during cultivation period, and also to estimate biological half-lives for residues of clothianidin and fluquinconazole. METHODS AND RESULTS: Two groups of peach were treated under Korean GAP (Good Agricultural Practices) with application time, single and triple treatments. Sample was collected over 14days (each after 0, 2, 4, 6, 8, 10, 12, 14 days. 8times), and clothianidin and fluquinconazole were analyzed by HPLC/DAD and GC/ECD, respectively. CONCLUSION: The biological half-life of clothianidin in single treatment and triple treatment was 5.2days and 7.0days. That of fluquinconazole was also 3.9days and 4.1days, respectively. The PHRL of peach on 10days before harvest was 1.4 mg/kg in clothianidin and 1.8 mg/kg in fluquinconazole.

Glial Fibrillary Acidic Protein Splice Variants in Hepatic Stellate Cells - Expression and Regulation

  • Lim, Michelle Chin Chia;Maubach, Gunter;Zhuo, Lang
    • Molecules and Cells
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    • 제25권3호
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    • pp.376-384
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    • 2008
  • The glial fibrillary acidic protein (GFAP) is traditionally used as a marker for astrocytes of the brain, and more recently for the hepatic stellate cells (HSCs) of the liver. Several GFAP splice variants have been previously reported in the astrocytes of the CNS and in the non-myelinating Schwann cells of the PNS. In this study, we investigate whether GFAP splice variants are present in the HSCs and their expression as a function of HSCs activation. Furthermore, the regulation of these transcripts upon treatment with interferon gamma ($IFN-{\gamma}$) will be explored. Using semi-quan-titative RT-PCR and real-time PCR, we examine the expression and regulation of GFAP splice variants in HSCs as well as their respective half-life. We discover that most of the GFAP splice variants ($GFAP{\alpha}$, ${\beta}$, ${\delta}$, ${\varepsilon}$ and $\kappa$) found in the neural system are also expressed in quiescent and culture-activated primary HSCs. Interestingly, $GFAP{\alpha}$ is the predominant form in quiescent and culture-activated primary HSCs, while $GFAP{\beta}$, predominates in the SV40-immortalized activated HSC-T6. $GFAP{\delta}$, ${\varepsilon}$ and ${\kappa}$ have similar half-lives of 10 hours, while $GFAP{\beta}$ has a half-life of 17 hours. Treatment of HSC-T6 with $IFN-{\gamma}$ results in a significant 1.29-fold up-regulation of $GFAP{\alpha}$ whereas the level of the other transcripts remains unchanged. In summary, $GFAP{\alpha}$, ${\beta}$, ${\delta}$, ${\varepsilon}$ and $\kappa$ are present in HSCs. They are differentially regulated on the transcription level, implying a role of the 5' and 3' untranslated regions.

CAN WE MEASURE A REMOTE SENSING SCIENCE? BIBLIOMETRIC ANALYSIS OF THE LITERATURE, 1975-2005

  • Nabiullin, Ahat A.;Shoom, Mariya Yu.
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.340-343
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    • 2006
  • Remote sensing science is a rapidly growing field of Earth sciences. Since emergence and to present day, an extensive literature has evolved which traces the wide application of remote sensing in human activities. According to the ISI Web of Science in the 1975-2005 time span more then 20,000 papers were published on remote sensing. The number of papers grew exponentially with doubling period of about 6 years. Notwithstanding all specialized proceedings, there is a lot more remote sensing papers published in a vast list of source titles (up to 350 proceedings). Only 25% of retrieved papers are published in 10 proceedings which ISI assigns to subject category of remote sensing. In 2005 all these proceedings published 1291 articles and received cca 24,000 citations. Average impact factor of the proceedings is equal to 1.181 and average cited half-life is 7.1. It means that an average paper in remote sensing proceedings is cited more then once per year and half of citations the paper receive within the next 7 years after publication. The time line of remote sensing periodicals issued in 1927-1995 shows an exponential growth with doubling period about 15 years. After 1995 there is a prominent deviation from the exponential curve which shows the demand saturation for specialized proceedings. The features revealed are discussed in terms of dynamics and impact of remote sensing in current Earth sciences development.

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식도암 환자의 GET 영상 평가 (GET Imaging Evaluation of Patients with Esophageal Cancer)

  • 문종운;이충운;서영덕;윤상혁;김용근;원우재
    • 핵의학기술
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    • 제17권2호
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    • pp.31-36
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    • 2013
  • 위배출 시간 측정(Gastric Emptying Time, GET)은 비침습적이고 정량적 평가 방법으로서 주로 내시경이나 방사선적 검사로 기계적 폐쇄가 없음이 확인된 위정체 증상을 보이는 환자를 검사한다. 이와 같은 일반적인 위배출 시간 측정 검사 외에 식도암 환자(식도 절제술을 시행한)를 대상으로 수술 직후와 1년 이상의 시간이 지난 후의 위배출 시간 측정 검사를 시행하여, 수술 후 흉강내에서 위장 기능의 평가 자료로서 위배출 시간 측정 검사의 유용성을 평가하고자 한다. 본원을 내원해서 식도 절제술을 시행한 환자 93명을 대상으로 위배출 시간 측정 검사를 수술 직후와 1년 이상의 시간이 지난 후에 두 번 시행하였다. 환자의 검사 전 준비사항으로는 12시간 이상 밤새 공복과 약재나 흡연을 중단 시켜야 하고 당뇨병 환자는 인슐린 주사 후 아침 일찍 검사하는 것이 이상적이다. 검사 방법은 유동식의 위배출 시간 측정은 예민도가 떨어지므로 시행하지 않고, 고형식의 위배출 시간 측정 방법으로 $^{99m}Tc-DTPA$로 표지된 레진이 들어간 계란찜, 그리고 김밥과 점성이 높은 발효유와 함께 먹은 후 입위 자세로 3시간 동안 측정하였다. 검사의 평가 방법은 위배출 곡선 상에서 위내 방사능치가 50%가 되는 시간, 즉 반감기(T1/2)를 구하였고, 반감기가 180분 이상시 지연 위배출, 180분 이내는 중등도, 삼킴과 동시에 소장으로 넘어가는 경우를 급속 위배출로 구분하였다. 일반적인 위배출 시간 측정 영상은 위의 전정부와 위저부가 강하게 나타나는 영상에서 시간이 지남에 따라 소장으로 넘어가는 영상이지만, 식도 절제술을 시행한 식도암 환자는 흉강쪽에 강한 집적 영상을 보였다. 수술 직후 반감기(T1/2)는 급속 위배출이 12.9%, 중등도 위배출이 52.7%, 지연 위배출이 34.4%로 나타났다. 이후 1년 이상의 시간이 흐른 뒤의 반감기 결과는 수술 직후 급속 위배출 환자 중 67%가 중등도 위배출로, 지연 위배출을 보였던 환자는 69%가 중등도 위배출로 나타났다. 중등도 위배출을 보였던 환자 중 급속 위배출 이나 지연 위배출로 나빠진 경우는 24%이다. 식도 절제술을 시행한 식도암 환자의 위배출 시간 측정 검사는 반감기(T1/2)가 급속 위배출 및 지연 위배출에서 시간이 지날수록 중등도 위배출로 변하는 소견을 보였다. 이는 주로 위를 보는 위배출 시간 측정 검사가 흉강내의 식도를 대신하는 위장 기능의 평가에도 유용하게 쓰일 수 있다는 것을 의미한다. 그리고 평가 기준을 세분화하고 검사의 시간 간격을 좁힌다면 좀 더 많은 정보와 분석으로 정확한 임상 진단과 평가가 이루어질 것으로 보인다.

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국내 과학기술 연구자의 한국 학술지 인용패턴 연구 (A Study of Citing Patterns of Korean Scientists on Korean Journals)

  • 최선희;김병규;강무영;류범종;이종욱;박재원
    • 정보관리학회지
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    • 제28권2호
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    • pp.97-115
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    • 2011
  • 국내 과학기술 분야 연구자들의 인용행태를 종합적으로 파악하고 분석하기 위해서는 대규모의 신뢰할 수 있는 인용색인 데이터베이스가 필요하다. KISTI는 한국 과학기술 인용색인 데이터베이스인 KSCD를 구축하고 한국과학기술인용보고서(KJCR) 및 한국과학기술인용색인서비스(KSCI)를 제공하고 있다. 본 논문에서는 국내 핵심 학술지 459종의 학술지를 커버하는 KSCD를 활용하여 국내 과학기술분야 연구자들의 한국 학술지 인용행태를 분석 연구를 수행하였다. 연구 범위로는 첫째, 대상 DB 수록 학술지의 통계적 주요 수치정보를, 둘째, 인용문헌의 형태별 분석을, 셋째, 인용문헌의 국내와 해외비율 및 타분야 인용비율을, 넷째, 국내 인용문헌의 즉시인용, 인용절정기, 반감기를 마지막으로 KJCR 인용지표를 통한 학술지의 영향력 분석이다. 국내학술지 인용분석을 통한 연구의 주요 성과로는 국내 인용 학술지의 즉시인용률(평균 2.36%), 인용절정기(평균 1.7년), 반감기(평균 5.2년)의 규명과 모든 주제분야에서 자기학술지 인용률이 평균 50%를 넘는다는 것을 밝힌 것이다. 본 연구를 통해 국내 과학자들의 국내 학술지 인용행태를 과학기술 전분야에 걸쳐 종합적으로 파악할 수 있었다.

돼지와 랫트에서 sulfamethazine의 약물동태학 및 조직분포 (Pharmacokinetic profile and tissue distribution of sulfamethazine in pigs and rats)

  • 윤효인;박승춘;오태광;조준형;박종명
    • 대한수의학회지
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    • 제37권2호
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    • pp.291-299
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    • 1997
  • In order to establish optimal dosage schedules and withdrawal times for sulfamethazine(SMZ) in pigs, pharmacokinetic and tissue distribution experiments were conducted in pigs. For comparative purposes, tissue depletion kinetics are also studied in rats. From three pigs administered with SMZ i.v., the pharmacokinetic profile of SMZ in two pigs was adequately described by a one-compartment open model whereas that in one pig was patterned after a two-compartment open model. Volume of distribution(Vd) was 0.48~0.57 L/kg and biological half-life($t_{1/2}$) was 11.8-16.8 h. From three pigs dosed with SMZ p.o., pharmacokinetic profile was explainable with a one-compartment open model. Time to reach maximum SMZ concentration in serum (Tmax) was 2.8 h, 3.2 h and 7.5 h. Elimination half-life was 2.8-7.5 h. The descending order in concentration of SMZ was plsama > kidney > liver > lung > heart > pancreas > spleen > duodenum > ileum > brain > adipsoe tissue from three pigs sacrificed at 5h, 29h and 54h after the administration of SMZ, p.o.. The protein binding of SMZ in pigs was 55.2%($2.5{\mu}g/ml$), 71.5% ($5{\mu}g/kg$) and 71.5%($10{\mu}g/ml$). The mean systemic bioavailability (F) of SMZ p.o. was 49.1 %. Meanwhile the pharmacokinetic profile of SMZ in rats was adequately described by a one-compartment open model. Absorption of SMZ p.o. in the rat was very rapid. In conclusion, the oral optimal dosage regimen of SMZ for pigs was the initial dose of 45.7 mg/kg followed by the maintenance dose of 30.2 mg/kg for high specific pathogens to SMZ. The time to reach below the stipulated residual allowable concentration (0.1 ppm) was calculated 93 h after oral administration of 200 mg/kg recommended by manufactureres.

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Radiolabeling of nanoparticle for enhanced molecular imaging

  • Kim, Ho Young;Lee, Yun-Sang;Jeong, Jae Min
    • 대한방사성의약품학회지
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    • 제3권2호
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    • pp.103-112
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    • 2017
  • The combination of nanoparticle with radioisotope could give the in vivo information with high sensitivity and specificity. However, radioisotope labeling of nanoparticle is very difficult and radioisotopes have different physicochemical properties, so the radioisotope selection of nanoparticle should be carefully considered. $^{18}F$ was first option to be considered for labeling of nanoparticle. For the labeling of $^{18}F$ with nanoparticle, Prosthetic group is widely used. Iodine, another radioactive halogen, is often used. Since radioiodine isotopes are various, they can be used for different imaging technique or therapy in the same labeling procedures. $^{99m}Tc$ can easily be obtained as pertechnatate ($^{99m}{TcO_4}^-$) by commercial generator. Ionic $^{68}Ga$ (III) in dilute HCl solution is also obtained by generator system, but $^{68}Ga$ can be substituted for $^{67}Ga$ because of the short half-life (67.8 min). $^{64}Cu$ emits not only positron but also ${\beta}-particle$. Therefore $^{64}Cu$ can be used for imaging and therapy at the same time. These radioactive metals can be labeled with nanoparticle using the bifunctional chelator. $^{89}Zr$ has longer half-life (78.4 h) and is used for the longer imaging time. Unlike different metals, $^{89}Zr$ should use the other chelate such as DFO, 3,4,3-(LI-1,2-HOPO) or DFOB.

지질 수액체 투여가 정상인의 혈장 지질변화에 미치는 영향 (Effects of Parenteral Lipid Formulas on Seurm Lipids Clearance in Normal Volunteers)

  • Choe Myeon·Kim
    • Journal of Nutrition and Health
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    • 제25권6호
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    • pp.461-467
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    • 1992
  • Total parenteral nutrition(TPN)의 구성성분으로써 지방질 수액제의 사용은 점차 많아지고 있지만 사용량이나 사용대상에 대해서는 아직도 규명해야 할 것이 많다. 본 연구에서는 시판 지방질 수액제들을 사용했을 때 이들이 혈청 지질변화에 어떠한 영향을 미치는가를 비교검토하였다. 각각의 시판 지방질 수액제를 12명의 정상적인 사람에게 주사한 후 5분 간격으로 혈액을 채취하여 혈청내 각종 지질의 변화를 관찰하였다. 혈청내에서 지질이 감소되는 속도를 계산하기 위하여 혈청중 중성지방의 fractional removal rate(K)와 반감시간(t/2)를 intravenous fat tolerance test(IVFTT)를 사용하여 계산하였다. 측정한 각종 항목에서 두 시판 지방질 사이에 통계적 차이를 볼수 없었으며 어떤 부작용도 관찰되지 않았다. 또한 두 제품 모두 혈액중의 지질감소, 속도가 유사하였다.

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초음파 위배출 측정과 한의설문 간의 상관성 분석 (Correlation Analysis between Gastric Emptying Measurement by Ultrasonography and Korean Medical Questionnaires)

  • 조수호;이재홍;고석재;김진성;박재우
    • 대한한방내과학회지
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    • 제39권4호
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    • pp.570-591
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    • 2018
  • Objective: This study was designed to investigate the correlation between gastric emptying measurement by ultrasonography and the findings of various questionnaires of functional dyspepsia (FD) or in Korean medicine to explore the possibility of quantification of questionnaires. Methods: Eighty-eight patients (44 patients with FD and 44 healthy controls) were recruited from October 2016 to November 2017. Gastric emptying half-time (T1/2) was measured by ultrasonography at fasting, and at 0, 15, 30, 45, 60, 90, and 120 min after meals (apple juice, 500 ml, 224 kcal). The average half-time (average T1/2) was calculated by averaging all measured half-times. A visual analogue scale (VAS), food retention questionnaire (FRQ), damum questionnaire (DQ), cold and heat questionnaire (CHQ), deficiency and excess questionnaire (DEQ), spleen-qi deficiency questionnaire (SQDQ), Nepean dyspepsia index-Korean version (NDI-K), and quality of life of NDI (NDI-QoL) were filled out by all participants. Correlation between the average T1/2 and questionnaires were analyzed for 79 patients (37 patients with FD and 42 healthy controls) after excluding missing and erroneous data. Results: The FRQ, DEQ, SQDQ, NDI-K, and NDI-QoL scores, especially for some gastrointestinal symptoms and general weakness-related symptoms, showed statistically significant correlations with average T1/2. Conclusions: Our results suggest that gastric emptying measurement by ultrasonography may be a quantitative substitute method for some Korean medical questionnaires or for some dyspepsia-related and deficiency-related items among them. However, further studies using various measurements of gastric emptying will be needed.

대전지역 주부의 건강식생활과 관련된 식습관과 식품구매행동 조사 (A Study of Food Habit and Food Purchase Behavior on Healthy Dietary Life by Housewives in Daejeon)

  • 유지현;구난숙
    • 한국생활과학회지
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    • 제22권2호
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    • pp.375-389
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    • 2013
  • This survey was conducted to compare the housewife's food habit and food purchase behavior on healthy dietary life. The questionnaires were collected from 151 working housewives and 159 housewives in Daejeon. The average meal time was 20~30 min., 67.6% of respondents ate breakfast and bap with guk(72.9%) was the most favourite foods. Almost half of them ate egg, fruit, vegetable everyday. They concerned highly about less intake of frozen foods(64.2%) and food additives(61.6%) for wellbeing dietary life. Because of close distance and various foods items, big discount store was chosen as food purchase place. The most considering purchase factor was food additives in working housewife and nutrition in housewife(p<0.05). In grocery shopping, working housewife considered children and their husbands(p<0.05). The most important purchase factor was the freshness in vegetables fishes fruits seaweeds eggs. TV or Radio was utilized the most frequently to obtain the useful knowledge on healthy foods. It is suggested that practical information should be offered housewives to purchase proper foods within their income and to manage dietary life according to their family's health condition.