• 제목/요약/키워드: Half Life

검색결과 1,832건 처리시간 0.023초

경북지역 현대화 원예시설의 관리실태 조사분석 (Analysis of Research for the Actual State and Management of Automated Horticultural Facilities)

  • 정현교;이기명;박규식
    • 생물환경조절학회지
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    • 제5권2호
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    • pp.174-186
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    • 1996
  • This study was carried out in order to understand the plan, design, constructing and actual condition of management of modernized horticultural facilities in Kyungpook Province which had been constructed from 1992 to 1995 funded by Government support. The aim of this study is to provide reference data for success of the forth project. It was performed by making up a question about driving of project and management condition of equipment after constructing. The results obtained from this study are as follows: 1. 73.5% of facilities horticulture farmhouse recognized that the prospect of greenhouse is bright, but 92.5% of the farmhouse also recognised that they need technical consultation on protected horticulture farming. Therefore, technical educations would must be enhanced about foundation of greenhouse and cultivation technique. 2. The holding times of explanatory meetings, cause of understanding to farmhouse, were one or two times in greenhouse construction, and 62.5% of the farmhouse expressed the insufficiency at the explanation and educational data. For this reason, it was judged that the construction contract had been delayed more than 5 months in 49.3% of the farmhouse after the decision of project budget. 3. In constructing after a contract, the rates of construction delay is 53.4% and defect occurrence is 41.1%. The biggest reasons of construction delay was insufficiency of worker and materials supply. Each percentage is 29.1%. And the reason of defect occurrence is badness of machinery equipment(62.9% ). 4. In management of greenhouse, a pipe-constructed plastic film greenhouse changes plastic film every one and three years because of sticking dust on plastic film. It was needed to about in cleaning technique of coverings. Because that used 3-5 years only half of the expected life span. 5. The order of broken rating in the subsidiary equipment is like this lollop ventilator (42.8%), a general control system(33.3%) especially, in the case of a general control system, the rate of all family can control is 52.7%. so, it is time to develop easy control equipment which every one could use as soon as possible. 6. When choose heat generator as decide capacity, the most priority is the mount of heat generator the percent is 45.5% heat generator and as decide model, the private purchase's percent is 77.3%. It is higher than a public bidding heat generator the percent is 22.7% heat generator when it compare with a public bidding. In the case of $CO_2$ generator, using rate is only 19.0%. The using rate is very low, so it needs education how to use depends on the way of the subsidiary equipment. 7. In the case of seedlings, it is asked to use factory-processed seedling effectively. because it's difficult to get security of labors(58.8%), hoped crops (55.9%) access same crops(29.4%) much more and changing of crops depends on market situation. that is the main reason the lack of knowhow.

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유전자 재조합 기술에 의하여 제조된 인간 ${\beta}-carotene$ 15,15'-dioxygenase의 반응특성 (Characterization of Human ${\beta}-Carotene$ 15,15-dioxygenase Isolated from Recombinant Escherichia coli)

  • 신원필;장판식
    • 한국식품과학회지
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    • 제36권3호
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    • pp.440-447
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    • 2004
  • 본 연구에서는 유전자 재조합 기술에 의해 제조된 ${\beta}-carotene$ 15,15'-dioxygenase의 반응특성 및 효소 kinetics를 규명하였다. ${\beta}-carotene$ 15,15'-dioxygenase 효소반응을 위한 최적 온도 및 pH를 측정한 결과, 최적 온도는 $40^{\circ}C$로 판명되었으며 최적 pH 는 9.0이었다. 저장 pH 6.0-9.0 범위에서 안정하였으며, pH 11에서도 80% 이상의 활성을 보이는 호알칼리성 효소임을 확인하였다. 온도 저장성을 확인한 결과, $35^{\circ}C$에서의 효소활성 반감기가 40분으로서 열에 민감한 것으로 판단되었다. 한편, ferrous ion-chelating agent와 sulfhydryl-binding agent를 사용하여 ${\beta}-carotene$ 15,15'-dioxygenase에 미치는 영향을 살펴 보았다. Ferrousion-chelating agent인 ${\alpha},{\alpha}'-dipyridyl$과 1,10-phenanthroline은 $1{\times}10^{-4}$ M에서 최소 저해농도를 형성하였으며, sulfhydryl-binding agent인 iodoacetamide와 PCMB는 $1{\times}10^{-3}$ M에서 N-ethylmaleimide은 $1{\times}10^{-4}$} M에서 최소저해농도를 형성함을 확인할 수 있었다. 본 연구에서의 효소반응은 Michaelis-Menten 곡선을 따름을 확인하였으며, Hanes-Woolf 작도법에 따른 결과, ${\beta}-carotene$ 15,15'-dioxygenase 효소의 $K_{m}$$V_{max}$ 값은 각각 $3.39{\times}10^{-6}$ 및 1.2 pmol/mg protein/min인 것으로 산출되었다.

원자력 시설 인근 수계에서 방사성 세슘 제거를 위한 일라이트 개질 연구 (Study on the Illite Modification for Removal of Radioactive Cesium in Water Environment near Nuclear Facilities)

  • 황정환;정성욱;신우식;한원식
    • 자원환경지질
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    • 제51권2호
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    • pp.113-120
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    • 2018
  • 체르노빌과 후쿠시마와 같은 원자력 사고를 통해 환경으로 방출되는 방사성 세슘($^{137}Cs$)은 화학적 독성과 ${\gamma}$ 선 방출, 그리고 긴 반감기($t_{1/2}=30.2$ 년) 때문에 주된 감시대상 방사성 핵종 가운데 하나이다. 1족 알칼리 금속인 세슘은 점토광물에 잘 흡착되며, 특히 운모류 광물인 일라이트와 특이적 흡착을 하는 것으로 알려져 있다. 이는 일라이트의 frayed edge sites 에 세슘이 선택적 흡착을 일으키기 때문이며, 이러한 흡착 지점은 일라이트의 풍화 정도 및 결정도에 따라 달라질 수 있다. 따라서 본 연구는 인공 풍화 실험(pH=2.0 at $50^{\circ}C$)을 통해 일라이트 표면을 개질함으로써 세슘의 흡착 성능을 증가시키기 위해 수행되었다. 일라이트의 층간 양이온들(K, Ca)은 반응 1일 이내에 다량 용출되는 반면, 결정 구조를 구성하는 Si와 Al은 점진적으로 용출되었다. 또한 일라이트 시료의 결정도가 감소하여 인위적인 화학적 풍화가 발생하였음을 지시하였다. 저농도의 세슘과 흡착 실험을 진행한 결과, 흡착분배계수가 기존에 비해 약 2배 증가하였다. 이러한 결과는 비교적 저온에서 손쉽게 일라이트의 흡착 성능을 개선할 수 있음을 암시한다.

三重水素($^{3}H$) 放射能의 生理分析에 關한 硏究 (A Study on Bioassay of Tritium($^{3}H$) Radioacitivity)

  • 황선태;오필재;김원식
    • 한국대기환경학회지
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    • 제3권1호
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    • pp.27-33
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    • 1987
  • 삼중수소 ($^{3}H$) 에 관한 환경 및 생물학상의 연구는 1950년대 중반부터 선진국에서 수행되오고 있다. 삼중소소에 대한 잠재적 노출의 경우 통상적 처리절차는 삼중수소의 신체부하량이라고 일컬어지는 이른바 신체내에 축적된 삼중수소의 양을 결정하기 위하여 삼중수소수로서 오줌속에 포함되는 삼중수소 방사능의 생리분석이다. 전신에 있어서 삼중수소의 최대허용신체부하량은 신체조직에 대하여 약 $30{\mu}Ci/{\ell}$ 이다. 생리분석에서 오줌속에 삼중수소를 검출하는데 가장 보편적인 조사준위(照射准尉)는 최대허용신체부하량의 1/10 이다. 이러한 생리분석 연구계획을 위해서는 소광보정(消光補正) 곡선을 그리는 것이 가장 우선적이다. 이것은 검뇨용 오줌의 색깔이 일정하지 않기 때문에 필요한 것이다. 이 경우에서 소광효과는 주로 오줌시료에 의한 섬광빛의 흡수에 기인된다. 소광보정곡선으로 판단된 공식은 통계적 근거에서 최소자승법에 의하여 Y (%) = 0.771 + 1.836 ${\tmes}10^{-4}$X(count)로 얻어졌다. 여기서 Y는 섬광계수 효율로서 약 12%에서 31% 범위의 값으로 나타났다. 본 논문에서는 삼중수소의 생물학적 반감기와 신체계통적으로 분포된 삼중수소에 적용되고 있는 정체(停滯) 공식에 관한 간략한 이론에 관하여 서술된다.

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아지도싸이미딘의 지속성방출형담체로서의 소수성시클로덱스트린유도체 (Hydrophobic Cyclodextrin Derivatives as a Sustained Release Carrier of Azidothymidine)

  • 서보연;박기배;이광표
    • Journal of Pharmaceutical Investigation
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    • 제26권2호
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    • pp.71-82
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    • 1996
  • This study has been undertaken to evaluate hydrophobic cyclodextrin(CD) derivatives as a sustained release carrier of azidothymidine(AZT), AZT, which has potent activity against AIDS and AIDS-related complex as thymidine analogue, has been reported that it has significant toxicity and short half life. Therefore, it is necessary to design sustained release oral dosage form to avoid undesirable side effects attributable to an excessive plasma concentration and to reduce the frequency of administration of AZT. Inclusion complexes of AZT with $acetyl-{\beta}-cyclodextrin\;(AC{\beta}CD)$ and $triacetyl-{\beta}-cyclodextrin(TA{\beta}CD)$ were prepared by solvent evaporation method. Interactions of AZT with CD were investigated by Differential Scanning Calorimetry(DSC) and Infrared Spectrophotometry(IR). The decreasing order of water solubilities of AZT and AZT-CD inclusion complexes were as follows; $AZT\;(27.873{\pm}0.015,mg/ml)\;>\;AZT-AC{\beta}CD\;(3.377{\pm}0.003)\;>\;AZT-TA{\beta}CD\;(2.528{\pm}0.001)$. Partition coefficients of $AZT-AC{\beta}CD\;and;\AZT-TA{\beta}CD$ inclusion complexes were increased by 1.27-fold, 1.54-fold in pH 1.2 and 1.32-fold, 1.47-fold in pH 6.8 in comparison with that of AZT. The mean dissolution time (MDT, min) which represents the rapidity of dissolution rate of AZT, $AZT-AC{\beta}CD,\;AZT-TA{\beta}CD$ were 5.12, 14.02 and 19.38 min in pH 1.2 and 2.52, 15.19 and 18.19 min in pH 6.8. AZT was very rapidly and completely dissolved in pH 1.2 and pH 6.8 within 5 minutes. But AZT-CD inclusion complexes showed the sustained release pattern in comparison with AZT alone. The simultaneous in situ nasal and jejunal recirculation study to compare the intrinsic absorptivity and the property of absorption sites revealed that the absorption of $AZT-TA{\beta}CD\;(N:35.35{\pm}1.08%,\;J:27.47{\pm}1.18%)$ was more than that of $AZT\;(N:16.89{\pm}2.25%,\;J:15.86{\pm}2.33%)$. The above results suggest that $TA{\beta}CD$ which is a hydrophobic cyclodextrin may serve as sustained release carrier with absorption enhancing effect.

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인체혈장 중 에탐부톨의 HPLC 분석법의 검증 및 단일용량 투여에 의한 약물동태 연구 (Determination of Ethambutol n Human Plasma by a Validated HPLC Method and Its Application to Single-dose Pharmacokinetics)

  • 곽혜선;박경호;최준식;송진아;성민경;장정옥;이화정
    • Journal of Pharmaceutical Investigation
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    • 제35권2호
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    • pp.123-127
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    • 2005
  • An HPLC method was employed for the determination of ethambutol in human plasma. After addition of internal standard (IS, octylamine, $2\;{\mu}g/mL$) and alkalinization of the plasma with 5 M sodium hydroxide, the drug and IS were extracted into the mixture of chloroform and diethyl ether (40:60, v/v). Following a 15-min vortex-mixing and a 10min centrifugation, the organic phase was spiked with $100{\mu}L$ of phenylethylisocyanate $(2000{\mu}g/mL)$ for chemical derivatization, mixed for 5 min and evaporated to dryness under a stream of nitrogen. The residue was reconstituted with $100{\mu}L$ of mobile phase and $20{\mu}L$ was injected into C18 column with a mobile phase consisting of methanol:water (70:30, v/v). The samples were detected utilizing an ultraviolet detector at 200 nm. The method was specific and validated with a limit of $0.15\;{\mu}g/mL$. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of this method was demonstrated by analysis of human plasma after oral administration of a single 1200-mg dose to 20 healthy subjects. From the plasma ethambutol concentration vs. time curves, the mean AUC was $9.61{\pm}1.64\;{\mu}g{\cdot}hr/mL$ and Cmax of $2.68\;{\mu}g/mL$ reached 2.73 hr after administration. The mean biological half-life of ethambutol was $3.46{\pm}1.21$ hr. Based on the results, this simple and validated assay could readily be used in any pharmacokinetic studies using humans.

인체 혈장중 라베프라졸의 정량을 위한 LC-MS/MS 분석법 검증 및 단일 용량 투여에 의한 약물동태 연구 (Validation of LC-MS/MS Method for Determination of Rabeprazole in Human Plasma : Application of Pharmacokinetics Study)

  • 탁성권;서지형;류주희;최상준;이명재;강종민;이진성;홍승재;임성빈;이경태
    • Journal of Pharmaceutical Investigation
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    • 제39권1호
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    • pp.73-78
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    • 2009
  • A simple LC-MS/MS method of rabeprazole in human plasma was developed and validated. Rabeprazole and Internal standard (I.S), omeprazole, were extracted from human plasma by liquid liquid extraction, chromatographic separation of rabaprazole in plasma was achieved at $45^{\circ}C$ with a Shiseido UG120 $C_{18}$ column and methanol-10 mM ammonium acetate buffer (pH 9.42 with ammonium water), as mobile phase. Rabeprazole produced a protonated precursor ion [$(M+H)^+$] at m/z 360.10 and corresponding product ion at m/z 242.21. Internal standard produced a protonated precursor ion [$(M+H)^+$] at 346.09 and corresponding product ion at m/z 198.09. This method showed linear response over the concentration range of $1{\sim}500\;ng/mL$ with correalation coefficient greater than 0.99. The lower limit of quantitation (LLOQ) using 0.2 mL plasma was 1 ng/mL, which was sensitive enough for pharmacokinetics studies. The method was specific and validated with a limit of quantitation of 1 ng/mL. The intra-day and inter-day precision and accuracy were acceptable for all samples including the LLOQ. The applicability of the method was demonstrated by analysis of plasma after administration of a single 10 mg dose to 36 healthy subject. From the plasma rabeprazole concentration versus time curves, the mean $AUC_t$ (The area under the plasma concentration-time curve from time 0 to 12 hr ) was $691.36{\pm}321.88\;ng{\cdot}hr/mL$, $C_{max}$ (maximum plasma drug concentration) of $353.21{\pm}131.52\;ng/mL$ reached $3.4{\pm}1.1\;hr$ after adiministration. The mean biological half-life of rabeprazole was $1.37{\pm}0.75\;hr$. Based on the results, this simple method could readily be used in pharmacokinetics studies.

Benzoylurea계 살충제 teflubenzuron과 flucycloxuron의 토양환경중 동태 (Behavior of benzoylurea insecticide teflubenzuron and flucycloxuron in soil environment)

  • 김태화;김장억
    • Applied Biological Chemistry
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    • 제36권6호
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    • pp.510-516
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    • 1993
  • Benzoylurea계 살충제인 teflubenzuron과 flucycloxuron의 토양환경 중 분해양상, urease 활성에 미치는 영향 및 용탈정도를 조사하였다. 안심과 칠곡지역 토양에서의 분해반감기는 flucycloxuron의 경우 50.1일과 102.3일로 나타났고, teflubenzuron의 경우에는 20.9일과 39.1일로 나타나 두 농약 모두 유기물 함량이 많고 pH가 다소 높은 안심지역 토양에서 더 빨리 분해되었다. 두 약제간에는 teflubenzuron이 flucycloxuron보다 안심지역 토양에서 29.2일 칠곡지역 토양에서는 63.2일 정도 더 빨리 분해되었다. Teflubenzuron과 flucycloxuron의 살균토양에서의 분해율은 120일 경과 후 두 토양에서$24.7{\sim}40.1%$ 정도로 분해가 상당히 지연되었다. 두 약제의 처리에 의한 토양내의 urease 활성에 미치는 영향은 농약처리 직후에는 무처리구에 비해서 두 농약 모두 37.6에서 42.4% 정도로 저해를 나타내었으나 60일 경과 후에는 거의 저해를 나타내지 않았으며 120일 경과 후에는 활성을 약간 증가시키는 것으로 나타났다. Soil column을 이용하여 안심 및 칠곡지역 토양과 유기물을 완전히 제거시킨 모래에서 용출수에 의한 용탈실험을 행한 결과 두 약제의 표준품과 제품 모두 토양에 상관없이 표층으로부터 2.5 cm 이내에 $77.6{\sim}98.8%$ 정도로 잔류하였고 표층으로부터 5 cm 이하로는 전혀 용탈이 일어나지 않았다.

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5세 누리과정 교사용 지도서의 멀티미디어 콘텐츠 중 플래시에 대한 유아교사의 활용도 (5-year-old Nuri Course Teacher's Guidebook on Multimedia Content Use of Early Childhood Teachers in Flash)

  • 박선영;홍순옥
    • 한국콘텐츠학회논문지
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    • 제17권7호
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    • pp.527-537
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    • 2017
  • 본 연구는 5세 누리과정 교사용 지도서의 멀티미디어 콘텐츠 중 플래시에 대한 유아교사의 활용실태 및 만족도를 알아보고 앞으로의 교수학습을 돕는 콘텐츠 개발이 나아가야 할 방향이 되는 기초자료를 제공하는데 목적이 있다. 연구대상은 부산시에 소재한 유치원, 어린이집에 근무하는 유아교사 144명이며, 5세 멀티미디어 콘텐츠 중 플래시에 대한 인식 및 실행에 관한 설문지를 통해 자료를 수집하였다. 수집된 자료는 SPSS 18.0 프로그램을 사용하여 빈도와 백분율로 산출하여 분석하였다. 연구결과 첫째, 유아교사는 5세 멀티미디어 콘텐츠에 대해 대체로 만족해하고 도움을 받고 있다고 인식하고 있었다. 둘째, 실제 현장에서 멀티미디어 콘텐츠는 비교적 낮게 활용하고 있었으며 그 중 플래시에 대한 유아교사의 활용은 전체 응답자의 과반수이상이 잘 활용하고 있는 것으로 나타났다. 셋째, 대 소집단 활동영역과 생활주제별에 따른 활용과 만족도는 동화 동시 동극과 이야기나누기, 그리고 우리나라, 봄 여름 가을 겨울에서 가장 많이 활용하고 있었으며 그에 따른 만족도는 만족한다는 응답이 가장 많이 나타났다.

Criteria in ′Landscape and Memory′ as Sense of Place for the Sustainable Development of Korean Mountainous Landscape

  • Jino Kwon;Shin, Joon-Hwan;Park, Myoung-Sub
    • 한국제4기학회지
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    • 제17권2호
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    • pp.85-99
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    • 2003
  • Since the experience of major landscape change during last half of the century due to war and rapid urbanization, the traditional character has been weakened, and it is necessary for a reconsideration to improve the landscape for the future. To review these relationships, the importance of a comprehensive understanding of nature has been suggested. Therefore identification of a new concept based on the 'socio-cultural influence of landscape' and 'sense of place' which are related to peoples' previous experience, is required. Furthermore more practical definitions and criteria to reveal the relationship are necessary. Among the terms suggested to describe sense of place such as 'home', 'place identity', 'place-based meaning' and 'settlement identity' etc., the 'home' is selected to represent our surrounding landscape. For more practical classification of home landscape, additional terms are suggested and defined based on both the relationships between human beings and nature, and between memory derived from previous experience and shared values with in the community. The additional terms which are the most important in the role of landscape character related to humans' are; ⅰ) Personal Landscape: Landscape of an individual human, which derives from previous personal experience; involves distinguishable character for a given person, and it is emotional and flexible depending on circumstances. ⅱ) Ordinary Landscape: Landscape of the 'common interest' between members of a community, which is acceptable as a surrounding for everyday daily life, it produces the richness and variety of landscape. ⅲ) Kernel Landscape: Landscape of the 'common ground' which is acceptable to the majority members of the community, and it provides variety and stability for periods of time, and it could strongly represent community attitudes toward nature. ⅳ) Prototype Landscape: Landscape as the 'common denominator' of overall community from past to present and towards the future, which encompasses all the kernel landscape throughout history. It provides a sense of place, balances the homogeneity of character throughout overall communities. Some part of this can be shared throughout history to shape an overall sense of place. It can also represent short terms fashions. For a prototype landscape to reveal sense of place, there are a couple of points which we should underline the commencing point. Firstly, understanding the relationship between humans and nature should be based on a given character of surroundings. Secondly, reoccurring landscape elements which have sustained in history can lead to sense of place, and should be reviewed the influences between nature and humans.

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