• 제목/요약/키워드: Effective Half-life

검색결과 178건 처리시간 0.026초

Ketorolac Ester Enhancer-prodrugs: Preparation and Evaluation of Their Physicochemical Properties

  • Yun, Sung-Il;Kim, Jung-Sun;Yong, Chul-Soon
    • Journal of Pharmaceutical Investigation
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    • 제38권6호
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    • pp.405-412
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    • 2008
  • Six ester analogues of Ketorolac were synthesized as potential enhancer prodrugs for transdermal delivery. Solubility of these esters was determined in 10% propylene glycol (PG)/isotonic phosphate buffer (IPB) at room temperature while lipophilicity was obtained as partition coefficients (log P) and capacity factors (k') using HPLC. Stability of the prodrugs in skin extract and in plasma was investigated at $37^{\circ}C$. The lipophilicity of the potential prodrugs increased in proportion to their alkyl chain length. Good linear relationship between partition coefficients (log P) and capacity factors (log k') was observed ($R^2=0.9961$). All of the analogues were fairly stable but slowly degraded in IPB over a 12 hour period. However, their stability in skin extract and in plasma varied with most compounds gradually decomposing over a 12 hour period. Although unsaturation of the alkyl ester chain did not alter the over all lipophilicity of the compound, the half-life was significantly affected. In plasma, degradation of the esters was slower than in the skin extract, which is a desirable trait for enhancer-prodrugs. However, the overall hydrolysis in the skin extract needs to be facilitated for the development of an effective enhancer prodrug. The analogue with the shortest half life in the skin extract was the unsaturated C-12 analogue of 0.96 hr.

A preliminary study on real-time Rn/Tn discriminative detection using air-flow delay in two ion chambers in series

  • Sopan Das ;Junhyeok Kim ;Jaehyun Park ;Hojong Chang;Gyuseong Cho
    • Nuclear Engineering and Technology
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    • 제54권12호
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    • pp.4644-4651
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    • 2022
  • Due to its short half-life, thoron gas has been assumed to have negligible health hazards on humans compared to radon. But, one of the decay products with a long half-life can make it to be transported to a long distance and to cause a severe internal dose through respiration. Since most commercial radon detectors can not discriminate thoron signals from radon signals, it is very common to overestimate radon doses which in turn result in biased estimation of lung cancer risk in epidemiological studies. Though some methods had been suggested to measure thoron and radon separately, they could not be used for real-time measurement because of CR-39 or LR-115. In this study, an effective method was suggested to measure radon and thoron separately from the free air. It was observed that the activity of thoron decreases exponentially due to delay time caused by a long pipe between two chambers. Therefore from two ion chambers apart in time, it was demonstrated that thoron and radon could be measured separately and simultaneously. We also developed a collimated alpha source and with this source and an SBD, we could convert the ion chamber reading to count rate in cps.

예비영양교사의 학교에서의 영양교육 경험 및 방향 설정에 대한 인식 조사 (Experience and Vision of Nutrition Education by Nutrition Teacher Candidate in School)

  • 이은주;이해영
    • 한국식생활문화학회지
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    • 제24권4호
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    • pp.440-450
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    • 2009
  • The purposes of study were to survey the status of nutrition education in school and investigate the perception of nutrition teacher candidates concerning the direction and ideal method for nutrition education. A questionnaire was distributed to 554 nutrition teacher candidates from August to October, 2006. A total of 468 usable data were collected (84.5% response rate). The statistical data analysis was completed by using SPSS for Windows (ver. 10.0) for descriptive analysis, ANOVA and $X^2$-test. About 52% of respondents had nutrition education teaching experience. Half of the respondents indicated that the necessity for nutrition education stemmed from their own need for such education. The main problem in students' dietary life was 'the increasing intake of processed foods, instant foods and fast foods (4.23 out of Likert 5 point scale)' and the major nutritional problem was 'high calorie intake with low essential nutrients (3.96 out of Likert 5 point scale)'. Over half the respondents (53.4%) recommended that nutrition education be oriented towards behavioral change rather than knowledge delivery. Social learning theory was preferred mostly as an theory apt to nutrition education (60.3%) and the most effective means of education was referred to organizing the regular class for nutrition education (50.5%). The 'playing such as songs or game' was reported as both effective and realizable method in nutrition education.

Effects of Cold Pretreatment and Medium Composition on Anther Culture Initiation in Strawberry

  • Na, Hae-Young;Kim, Dae-Young;Chun, Chang-Hoo
    • 원예과학기술지
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    • 제29권5호
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    • pp.488-493
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    • 2011
  • Callus culture initiation of strawberry (Fragaria${\times}$ananassa Duch.) was investigated at different Murashige and Skoog (MS) medium strengths, types and concentrations of plant growth regulators, and incorporating a cold pretreatment period to determine the optimal nutritional and environmental conditions. No high quality callus was induced on MS media without auxin regardless of medium strength. When 6-benzylaminopurine (BA) was combined with indole acetic acid (IAA), naphthalene acetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D), high quality callus were highly induced compared to medium supplemented with auxin alone. When $0.5mg{\cdot}L^{-1}$ BA was combined with IAA, NAA, and 2,4-D, high quality callus induction was more effective than the medium supplemented with the other BA concentrations. The best combination of auxin and cytokinin for high quality callus induction was $1.0mg{\cdot}L^{-1}$ NAA and $0.5mg{\cdot}L^{-1}$ BA. Although the differences in callus induction were not significant, high quality callus induction at half strength MS medium was more effective than at full strength medium. When $30g{\cdot}L^{-1}$ sucrose was added to the half strength MS medium, the rate of high quality callus induction increased. The optimum cold pretreatment temperature and period for high quality callus induction were $4^{\circ}C$ and 72 h, respectively. Regeneration rate of high quality callus increased in MS medium supplemented with thidiazuron.

원자력 사고후 주민의 이주를 위한 유도개입준위 산정의 실용적 방법론 (A Practical Methodology for Determination of Derived Intervention Levels on Relocation Following a Nuclear Accident)

  • 황원태;김은한;서경석;정효준;한문희;이창우
    • Journal of Radiation Protection and Research
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    • 제29권2호
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    • pp.91-96
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    • 2004
  • 원자력시설의 사고로 인한 방사성물질의 환경 누출후 주민의 이주를 위한 유도개입주위 산정의 실용적 방법론을 지표면 선량율에 근거하여 고안하였다. 이주를 요하는 기간에 따라 잠정 이주와 영주이주로 구분하여 환경특성 변수 값에 따른 유도개입준위의 영향을 고찰하였다. 이주를 위한 유도개입준위는 방사성물질의 지표 침적후 핵종의 유효 제거 반감기, 측정 지연시간 피폭자의 거주특성 등에 따라 뚜렷이 다르게 나타났다. 특히 지표면 선량율이 지수함수 형태가 아닌 멱함수 형태의 감소를 가정하는 경우 측정 지연시간은 유도개입준위 설정에 있어 중요한 요소로 작용한다는 것을 알 수 있다. 핵종의 유효 제거반감기가 길수록 측정 지연시간이 늦을수록 그리고 피폭자가 오염원에 노출되는 시간이 길수록 유도개입준위는 보다 낮은 값을 나타냈다.

생산단계에서 소비단계 생식 쑥갓의 azoxystrobin 잔류량에 따른 위해성 평가 (Risk Assessment of Azoxystrobin Residues in Fresh Crown Daisy from Farm to Fork)

  • 반선우;오아연;장희라
    • 한국환경농학회지
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    • 제42권2호
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    • pp.131-138
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    • 2023
  • The biological half-life and dissipation rate of azoxystrobin in crown daisy were calculated to establish the pre-harvest residue limits (PHRLs). The pesticide residues were calculated after washing with five different processes to propose an effective process in the household and conducted a risk assessment to confirm dietary safety. Azoxystrobin was sprayed according to the critical good agricultural practices (cGAP) in two different field trials, and the samples were harvested 7 times. The limit of quantitation was 0.02 mg/kg, and the mean recoveries of azoxystrobin were within the range of 70~120% with below 20% coefficient variation at the concentration of 0.02 and 0.2 mg/kg . The biological half-lives were 7.4 and 4.7 days, and the dissipation rate constants were 0.0872 and 0.1217 in fields 1 and 2, respectively. The average removal rates were 58.13~78.13% by the different washing processes, and there were significant differences between the washing processes (one-way ANOVA analysis and post-hoc Duncan test, p-value<0.05). The residues of azoxystrobin in crown daisy were safe levels from farm to fork after application with the critical good agricultural practice (cGAP) registered in Korea.

A Study on Eating Habits, Life Styles and Nutrition Care of Diabetic Outpatients

  • Chang, Kyung-Ja;Nam, Moon-Suk
    • Journal of Community Nutrition
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    • 제1권2호
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    • pp.133-139
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    • 1999
  • The purpose of this survey was to investigate eating habits, life styles and nutritional care of diabetic outpatients and to provide basic data for developing individualized nutritional care and diabetic education programs. This survey was carried out by nutritional counseling with a questionnaire and checking medical record. Information about the general characteristics of the subjects, eating habits, health-related life styles and attitude and perception of subjects to diet therapy was gathered from 200 randomly-sampled diabetic outpatients at a University Hospital located in Inchon. All data were analyzed by Statistical Analysis System(SAS) software. The results are summarized as follows : Female subjects were 63.5% of total subjects and 65.5% of total subjects were 50 years or more. The average Body Mas Index(BMI) of male and female subjects were 23.06kg/㎡ and 25.02kg/㎡ respectively and 44% of all subjects wee obese. Among subjects, type II diabetic patients were 81.0% and 82.5% of subjects had suffered from diabetes for more than one year. Also 41% subjects had diabetic history in their family. More than half of the subjects had nutrition education concerning diabetes. Also 75.5% of them thought that nutrition education was effective. The most important guideline in diet therapy was to eat cooked rice with dietary fiber-rich grains. Therefore, it might be necessary to develop nutrition education program adjusted according to diabetic patient's needs and life styles, which may increase feasibility of self-care and implementation of management guidelines.

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Functional Gastrointestinal Disorders in Infancy: Impact on the Health of the Infant and Family

  • Vandenplas, Yvan;Hauser, Bruno;Salvatore, Silvia
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • 제22권3호
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    • pp.207-216
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    • 2019
  • Functional gastrointestinal disorders (FGIDs) such as infantile colic, constipation and colic occur in almost half of the infants. The aim of this paper is to provide a critical and updated review on the management of FGIDs and their impact on the health of the infant and family to health care physicians. Guidelines and expert recommendations were reviewed. FGIDs are a frequent cause of parental concern, impairment in quality of life of infants and relatives, and impose a financial burden to families, health care, and insurance. Therefore, primary management of the FGIDs should be focused on improving the infants' symptoms and quality of life of the family. If more than parental reassurance is needed, available evidence recommends nutritional advice as it is an effective strategy and most of the time devoid of adverse effects. The role of healthcare providers in reassuring parents and proposing the correct behavior and nutritional intervention by avoiding inappropriate use of medication, is essential in the management of FGIDs.

한국의학도서관(韓國醫學圖書館)에 있어서의 도서선택방법(圖書選擇方法)에 관한 연구(硏究) -인용문헌(引用文獻)의 계수(計數)와 분석(分析)을 중심(中心)으로- (A Study on the Selecting Method of Books for the Medical Library in Korea; Citation Countung and Analysis of the Medical Literature)

  • 신정원
    • 한국비블리아학회지
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    • 제2권1호
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    • pp.266-295
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    • 1974
  • The purpose of this study is to make a contribution to the effective management of medical literature in Korean libraries and specifically to help to select medical books and periodicals by determining the value and life of medical literature by means of citation counting and analysis. This report will present methods of calculation and data collection to measure the importance, half life of medical literature and the authority of author for Korean medical libraries. The writer conducted comparative studies based on data covering a two-year period, 1970-1971, using about 16,899 citations in 1,032 articles of the above journals. The references and citations are counted and analyzed by the number of authors, periodicals. books and publication dates. By the following ratio. calculated by the citation counting and analysis, we can decide the rates of medical periodicals to books, foreign literature to domestic literature and literature of the most numerously cited. authors, for the selecting method of Korean Medical libraries. (1) It is disclosed that 61 main authors are cited 9 times. Most of them are Western authors, they are cited 14,374 times which represents 88.6 % of the total citations. (2) The cited medical literature is classified as follows: The ratio of cited medical periodicals to the cited medical books is 82.0%. (The books at a rate of 18.0%.) Therefore, the wnter concentrated the efforts on the analysis of periodicals. (3) Classification of the periodicals by countries indicates that about 11.2% of total citations are made from Korean medical literature. The medical activities in Korea are dependent on the advanced foreign countries at ratio of 88.8%. Of the foreign medical periodicals cited, Japanese literature represents only 4.5% while literature of European countries and America constitutes 84.3%. (4) If medical journals are arranged in order of decreasing productivity of articles on a given subject, they may be revealed that it is necessary to have 98 titles of key journals to cover 60% of information in the field of medical science and 60 titles for an average of 50%. (5) For the purpose of measuring the life of medical literature in Korea, the writer has calculated the half lives of periodicals and books as follows: Kinds of Literature 1. Periodicals 2. Books 3. Whole literature Half-lives 7.75 years 4.11 years 6.37 years (6) The half lives of domestic and Japanese literature in the medical science are comparatively short.

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Genetic Analysis of Growth Response to Cold Water Irrigation in Rice

  • Han, Long-Zhi;Koh, Hee-Jong
    • 한국작물학회지
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    • 제45권1호
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    • pp.26-31
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    • 2000
  • This study was carried out to obtain the basic information for breeding cold-tolerant rice varieties with high yield-productivity through wide crosses between indica and japonica rice. Genetic analysis was conducted using 55 F$_1$s obtained from half-diallel crosses among eleven cultivars of various origin including indica and japonica rice. Screening for cold tolerance was done with cold-water irrigation after transplanting until ripening stage. Both general combining ability (GCA) and specific combining ability (SCA) effects were highly significant in all characters associated with dry matter accumulation at 30 and 50days after cold-water irrigation (DAC). The variance of GCA was much larger than that of SCA in plant height, shoot dry weight per plant (DWP), crop growth rate (CGR) and cold-water response index (CRI) of these characters except CRI of shoot dry weight per plant. The DWP, CGR and CRI of these characters of Gaochan 102, Tong88-7 and TR22183 were markedly higher than those of the others. GCA effects of these varieties on DWP, CGR and their CRI were also higher than those of the others, indicating that they are useful as promising parents for breeding cold-tolerant varieties. Analysis of genetic parameters for 11$\times$11 half-diallel F$_1$s revealed that inter-locus gene interaction were concerned in the expression of plant height at 50 DAC, CRI of DWP at 50 DAC, and CRI of CGR, and that intra-locus gene interaction for plant height and the other characters were partial dominance and over-dominance, respectively. Narrow-sense heritability (h$^2$$_{N}$) was the highest in plant height as 0.729, and the lowest in CRI of DWP at 30 DAC as 0.048, suggesting that selection for cold tolerance will be quite effective in case that the selection criterion is the performance itself.f.

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