• 대한방사선기술학회지:방사선기술과학
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• 제36권4호
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• pp.291-297
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• 2013

본 연구는 NaI (Tl) 신틸카메라를 이용하여 동적영상 분석에서 계수율 오차가 $T_{1/2}$에 미치는 영향을 알아보고, 이에 대한 점 선원을 이용한 정도관리 방법을 제안하는 것에 목적을 두었다. 18.5 MBq 부터 185 MBq 까지 2 mL 용량의 $^{99m}TcO_4^-$을 주사기에 넣어 점 선원을 제작한 후, Infinia(GE, USA) 감마카메라를 이용하여 10초부터 60초까지 각각 30프레임의 동적영상을 획득하였다. 두 번째 실험으로 5대의 감마카메라(Infinia 2대, Forte 2대, Argus 1대)를 대상으로, 74 MBq의 점 선원으로 90프레임의 동적영상을 획득하였다. 첫 번째 실험의 평균계수율을 10초 단위로 비교한 결과 18.5 MBq부터 92.5 MBq까지의 선원은 10초/프레임에서 60초/프레임까지 평균계수율 간에 유의한 차이를 보이지 않았지만(p>0.05), 111 MBq 이상의 점 선원을 60초/프레임에서 계수율이 유의하게 적게 획득되었다(p<0.01). 이에 따라 5대의 감마카메라에서 90분간 획득한 계수율을 선형 회귀분석한 결과, 4번 감마카메라의 계수 효율은 0.0064%로 가장 낮았고, 경사도와 변동 계수는 각각 0.0042, 0.229로 가장 높게 측정 되었다. 계수율을 카이제곱검정한 결과에서는 비정상적인 요동을 확인하지 못하였고(p>0.02), 분산의 동질성 검정에서 또한 모든 감마카메라의 계수율 간에는 등분산성이 확인되었다(p>0.05). 상관분석에서는 유일하게 계수 효율과 경사도간에 유의한 음의 상관관계가 있는 것으로 분석 되었다(r=-0.90, p<0.05). 마지막으로 -2.5%부터 +2.5%까지 경사도를 변화하여 $T_{1/2}$의 오차를 산출한 결과, $T_{1/2}$이 길수록, 경사도가 높을수록 오차가 커지는 것으로 나타났다. 경사도가 가장 높았던 4번 카메라에서 측정된 수치를 이 결과에 미루어 보았을 때 $T_{1/2}$ 60분까지는 오차가 발생되지 않았다. 결론적으로 의료분야에 사용되는 신틸레이션 감마카메라에 있어 방사선 계수에 대한 엄격한 정도관리가 필요하다고 생각된다. 특히 본 연구에서 계수율이 시간에 따라 변화하는 경향이 파악되었고, 이는 $T_{1/2}$에 영향을 줄 수 있음을 증명하였다. 또한 국내 의료 목적의 신틸레이션 카메라의 계수율에 관한 권고치나 제한치가 없는 점을 미루어 볼 때, 본 연구와 같은 적절한 팬텀 및 관리법의 개발이 필요하다 사료된다.

• 한국토양비료학회지
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• 제13권1호
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• pp.21-32
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• 1980

Linear models, with and without site variables, have been investigated in order to develop an alternative methodology for determining optimal fertilizer levels. The resultant models are : (1) Model I is an ordinary quadratic response function formed by combining the simple response function estimated at each site in block diagonal form, and has parameters [${\gamma}^{(1)}_{m{\ell}}$], for m=1, 2, ${\cdots}$, n sites and degrees of polynomial, ${\ell}$=0, 1, 2. (2) Mode II is a multiple regression model with a set of site variables (including an intercept) repeated for each fertilizer level and the linear and quadratic terms of the fertilizer variables arranged in block diagonal form as in Model I. The parameters are equal to [${\beta}_h\;{\gamma}^{(2)}_{m{\ell}}$] for h=0, 1, 2, ${\cdots}$, k site variable, m=1, 2, ${\cdots}$ and ${\ell}$=1, 2. (3) Model III is a classical response surface model, I. e., a common quadratic polynomial model for the fertilizer variables augmented with site variables and interactions between site variables and the linear fertilizer terms. The parameters are equal to [${\beta}_h\;{\gamma}_{\ell}\;{\theta}_h$], for h=0, 1, ${\cdots}$, k, ${\ell}$=1, 2, and h'=1, 2, ${\cdots}$, k. (4) Model IV has the same basic structure as Mode I, but estimation procedure involves two stages. In stage 1, yields for each fertilizer level are regressed on the site variables and the resulting predicted yields for each site are then regressed on the fertilizer variables in stage 2. Each model has been evaluated under the assumption that Model III is the postulated true response function. Under this assumption, Models I, II and IV give biased estimators of the linear fertilizer response parameter which depend on the interaction between site variables and applied fertilizer variables. When the interaction is significant, Model III is the most efficient for calculation of optimal fertilizer level. It has been found that Model IV is always more efficient than Models I and II, with efficiency depending on the magnitude of ${\lambda}m$, the mth diagonal element of X (X' X)' X' where X is the site variable matrix. When the site variable by linear fertilizer interaction parameters are zero or when the estimated interactions are not important, it is demonstrated that Model IV can be a reasonable alternative model for calculation of optimal fertilizer level. The efficiencies of the models are compared us ing data from 256 fertilizer trials on rice conducted in Korea. Although Model III is usually preferred, the empirical results from the data analysis support the feasibility of using Model IV in practice when the estimated interaction term between measured soil organic matter and applied nitrogen is not important.

• 한국인구학
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• 제30권3호
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• pp.107-135
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• 2007

본 연구에서는 우리나라 가구의 자녀수 결정요인을 Count 모형을 이용하여 분석하였다. 분석 기법으로는 자녀수가 감마(Gamma) count 분포를 따른다는 가정 하에 기본적인 회귀분석과 40세 이하 기혼여성의 완결출산에 대한 대리변수로 예상출산자녀수에 대한 회귀분석, 허들모형 그리고 기혼여성의 노동시장 참여와 자녀출산간의 내생성을 고려한 모형을 각각 이용하여 다각적인 방법론으로 출산결정요인을 분석하였다. 분석결과, 가구의 소득수준이 높을수록 40세 이상 기혼여성의 자녀수는 많은 것으로 나타나는 반면, $18{\sim}39$세 기혼여성의 경우에는 소득이 자녀수에 큰 영향을 미치지 못하는 것으로 보인다. 기혼여성의 경제활동참여는 39세 이하의 비교적 젊은 여성들에게서 출산 예상자녀수에 부정적인 영향을 주는 것을 뚜렷이 확인할 수 있고, 출산과 경제활동참여 간에는 내생성이 존재하는 것으로 확인되었다. 허들모형을 이용한 결과, 기혼여성의 학력은 자녀출산 여부에는 긍정적으로 작용할 수 있으나 자녀수 결정에는 부정적으로 작용하여 기혼여성 학력이 높을수록 출산율은 감소하게 된다. 다양한 회귀분석 결과에 근거할 때 Becker의 Quantity-Quality 모형의 핵심내용은 우리나라의 자녀수 결정에 있어서도 대체적으로 적용됨을 확인할 수 있다.

• 대한예방한의학회지
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• 제12권2호
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• pp.61-72
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• 2008

Objectives : The aim of this study was to evaluate effects of herbal medicine and other associated factors for abnormal liver function tests(especially total bilirubin, AST, ALT, and ${\gamma}$GT) levels in outpatients at an oriental medical clinic. Methods : A cross-sectional study based on clinical records was conducted on 504 patients at one Oriental medical clinic in Seoul, Korea. They were tested a liver function tests for screening and 497 patients ranging from the age of 4 to 74 were chosen for the study. Patients with basal liver disease or DM were excluded during the screening process. Patients were classified into case(abnormal) and control(normal) groups by normal liver function test references. Results and Conclusions : In this study, Significant correlations for abnormal total bilirubin levels was age, for abnormal AST was gender, for abnormal ALT were gender, smoking, marriage status, and job, for abnormal ${\gamma}$GT were age, gender, obesity, alcohol, smoking, marriage status, and job using the Chi-square test(p<0.05). There was no significant correlations for abnormal LFTs by using herbal medication history, and intake duration. After controlling other covariates, logistic regression analysis showed that the significant associated factors for abnormal total bilirubin levels were age(odds ratio[OR]=0.87, 95% confidence intervals [CI]=0.87-0.99). For abnormal AST levels was obesity(OR=2.45, CI=1.2-4.9), for abnormal ALT levels were age(OR=1.01, CI=0.99-1.03), male gender(OR=3.31, CI=1.62-6.76), and obesity(OR=3.71 CI=2.28-6.08). For abnormal ${\gamma}$GT levels were male gender(OR=4.83 CI=1.34-17.43), obesity(OR=3.29, CI=1.74-6.22), alcohol (OR=2.51, CI=1.19-5.28), and smoking(OR=2.29, CI=1.16-4.50). Herbal medication history was not as a risk factor for all abnormal liver function tests. Therefore, people who are male, obese, alcohol drinker and smoker will have higher liver function test levels. But intake of herbal medication or the duration of intake may not be the risk factor for abnormal liver function test results.

• Nutrition Research and Practice
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• 제12권2호
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• pp.160-165
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• 2018

BACKGROUND/OBJECTIVES: Korea is quickly becoming an aged society. Dementia is also becoming a vital public health problem in Korea. Cognitive impairment as a pre-stage of dementia shares most risk factors for dementia. The aim of the present study was to determine associations of serum levels of vitamins A, C, and E with the risk of cognitive impairment among elderly Koreans. SUBJECTS/METHODS: In this cross-sectional study, a total of 230 participants aged 60-79 years from Yangpyeong cohort were included. Cognitive function was assessed by the Korean version of the Mini-Mental State Examination for Dementia Screening. The logistic multivariable regression model was applied to determine the effect of serum vitamins A, C, and E on the risk of cognitive impairment. RESULTS: There was no significant association between the risk of cognitive impairment and serum levels of vitamin A and vitamin C. There was a significant odd ratio when the second tertile group of beta-gamma tocopherol level was compared to the first tertile group [odds ratio (OR) = 0.37, 95% confidence interval (CI) = 0.14-0.98, P for trend = 0.051]. In subgroup analyses, there were significant negative associations between beta-gamma tocopherol level and the risk of cognitive impairment in men (OR = 0.17, 95% CI = 0.03-0.87, P for trend = 0.028), non-drinkers or former drinkers (OR = 0.13, 95% CI = 0.02-0.66, P for trend = 0.025), and non-smokers or former smokers (OR = 0.27, 95% CI = 0.09-0.82, P for trend = 0.017). CONCLUSION: Serum beta-gamma tocopherol levels tended to be inversely associated with the risk of cognitive impairment. Further prospective large-scaled studies are needed to examine this association.

• 대한간호학회지
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• 제31권1호
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• pp.126-138
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• 2001

The purpose of this study is to act nursing intervention strategies to promote quality of life (QOL) in Spinal Cord Injury patients. Therefore, the study is designed to evaluate religion, marital status, educational background economic status, level of injury, voiding pattern, transportation by driving, rehabilitation education, self-concept, sexual status, perceived barrier, powerlessness, depression, hope, social support, self-efficacy, anxiety, ADL, perceived hopelessness, personality and pain for QOL at the same time. It was gathered empirical data was collected using a self report questionnaire from 61 patients during a six month period after SCI at 5 general hospitals, at 2 rehabilitation centers and at 2 rehabilitation schools province from Jun. 18, 1999 through Sep. 28, 1999. The reliability of the 19 instruments was tested with Cronbach's alpha which ranged from .6319 to .9769. For the data analysis a SAS program was used for Pearson correlation coefficients, and stepwise multiple regression. The results were as follows; 1. The mean of total item score in the QOL scale was 2.814, which showed a much lower score than the cancer points. 2. There was a significant correlation between self concept, transportation by driving, perceived barrier, powerlessness, depression, hope, social support, self-efficacy, anxiety, ADL and QOL.(${\gamma}$= .27~-.79, p< .05) 3. Stepwise multiple regression analysis showed that; a) Depression was the main predictor of QOL and account for 53.7% of the variance in QOL. b) Hope, ecomic status and body satisfaction accounted for 8%, 4%, 3.4% respectively and these variables combined accounted for 69.2% of the variance in QOL. In conclusion, to begin with, it is important to reduce depression and to help for SCI points to inspire hope, economic status and body satisfaction. That will be short cut for nursing strategies to enhance QOL.

• 한국연초학회지
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• 제22권2호
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• pp.184-189
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• 2000

This study was conducted to develop the objective evaluation method for tobacco smoke. The evaluation was carried out by using the data of cut or blended tobacco components, smoke components, electric nose system (ENS), and sensory test. By using the statistical methods, such as cluster analysis, discriminant analysis, factor analysis, correlation analysis, and multiple regression analysis, the relationship among the data of tobacco, smoke, ENS, and sensory evaluation was studied. By the results of cluster analysis, the data from smoke analysis by GC and ENS were able to select the difference of tobacco leaf characteristics. As the results of discriminant analysis, grouping by the components of tobacco leaves and smoke was possible and the results of GC analysis of smoke could be used for discrimination of tobacco leaves. In the results of factor analysis, nicotine, tar, CO, puff No and pH in the smoke were the factors effecting on the tobacco leaf characteristics. From the correlation analysis, aroma, taste, irritation, and smoke volume of sensory test had high relation to tar, p-cresol threonolatone, levoglucosane, and quinic acid- ${\gamma}$ -lactone of smoke. The ENS data showed high efficiency for discriminant analysis and cluster analysis, but it was not good for factor analysis, and correlation analysis. It was possible to estimate tobacco leaves and their blending characteristics by the analytical data of tobacco leaves, smoke, ENS, and sensory test results. By the multiple regression analysis, some correlation among selected chemical components and sensory evaluation were found. This study strongly indicated that the some chemical analysis data was available for the objective evaluation of tobacco sensory attributes.

• Asian Pacific Journal of Cancer Prevention
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• 제17권9호
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• pp.4421-4426
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• 2016

Background: Smoking is recognized as a main leading preventable cause of mortality and morbidity worldwide. It is responsible for a considerable financial burden both on the health system and in society. This study aimed to examine the effect of smoking on cost of hospitalization and length of stay (LoS) among patients with lung cancer in Iran in 2014. Materials and Methods: A total of 415 patients were included in the study. Data on age, sex, insurance status, type of hospitals, type of insurance, geographic local, length of stay and cost of hospitalization was extracted by medical records and smoking status was obtained from a telephone survey. To compare cost of hospitalization and LoS for different smoking groups, current smokers, former smokers, and never smokers, a gamma regression model and zero-truncated poisson regression were used, respectively. Results: Compared with never smokers, current and former smokers showed a 48% and 35% increase in hospitalization costs, respectively. Also, hospital LoS for current and former smokers was 72% and 31% higher than for never smokers, respectively. Conclusions: Our study indicated that cigarette smoking imposes a significant financial burden on hospitals in Iran. It is, however, recommended that more research should be done to implement and evaluate hospital based smoking cessation interventions to better increase cessation rates in these settings.

• 한국임상약학회지
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• 제28권2호
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• pp.107-116
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• 2018

Objective: This study analyzed the national claims data of veterans to generate scientific evidence of the trends and appropriateness of their drug utilization in an outpatient setting. Methods: The claims data were provided by the Health Insurance Review & Assessment (HIRA). Through sampling and matching data, we selected two comparable groups; Veterans vs. National Health Insurance (NHI) patients and Veterans vs. Medical Aid (MAID) patients. Drug use and costs were compared between groups by using multivariate gamma regression models to account for the skewed distribution, and therapeutic duplication was analyzed by using multivariate logistic regression models. Results: In equivalent conditions, veteran patients made fewer visits to medical institutions (0.88 vs. 1), had 1.86 times more drug use, and paid 1.4 times more drug costs than NHI patients (p<0.05); similarly, veteran patients made fewer visits to medical institutions (0.96 vs. 1), had 1.11 times more drug use, and paid 0.95 times less drug costs than MAID patients (p<0.05). The risk of therapeutic duplication was 1.7 times higher (OR=1.657) in veteran patients than in NHI patients and 1.3 times higher (OR=1.311) than in MAID patients (p<0.0001). Conclusion: Similar patterns of drug use were found in veteran patients and MAID patients. There were greater concerns about the drug use behavior in veteran patients, with longer prescribing days and a higher rate of therapeutic duplication, than in MAID patients. Efforts should be made to measure if any inefficiency exists in veterans' drug use behavior.

• Advances in environmental research
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• 제3권3호
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• pp.231-251
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• 2014

The present study examines the phosphate adsorption potential and behavior of mixture of Ground Burnt Patties (GBP), a solid waste generated from cooking fuel used in earthen stoves and Red Soil (RS), a natural substance in fixed bed column mode operation. The characterization of adsorbent was done by Proton Induced X-ray Emission (PIXE), and Proton Induced ${\gamma}$-ray Emission (PIGE) methods. The FTIR spectroscopy of spent adsorbent reveals the presence of absorbance peak at $1127cm^{-1}$ which appears due to P = O stretching, thus confirming phosphate adsorption. The effects of bed height (10, 15 and 20 cm), flow rate (2.5, 5 and 7.5 mL/min) and initial phosphate concentration (5 and 15 mg/L) on breakthrough curves were explored. Both the breakthrough and exhaustion time increased with increase in bed depth, decrease in flow rate and influent concentration. Thomas model, Yoon-Nelson model and Modified Dose Response model were used to fit the column adsorption data using nonlinear regression analysis while Bed Depth Service Time model followed linear regression analysis under different experimental condition to evaluate model parameters that are useful in scale up of the process. The values of correlation coefficient ($R^2$) and the Sum of Square Error (SSE) revealed the Modified Dose Response model as the best fitted model to the experimental data. The adsorbent mixture responded effectively to the desorption and reusability experiment. The results of this finding advocated that mixture of GBP and RS can be used as a low cost, highly efficient adsorbent for phosphate removal from aqueous solution.