• Applied Microscopy
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• v.22 no.1
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• pp.113-127
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• 1992

The present study was investigated to elucidate the effects of chlorambucil the heart tissue of various-aged rats. The male rats ranging from 3 to 36 months were used. The cytochemical and biochemical changes in myocardium of the rats were studied in the aspect of free radical roles in aging process. With the goals of evaluating the potential roles of free radicals in aging process, evidence was shought for alterations of myocardial lipid peroxide levels in control and chlorambucil treated rats. The result are summarized as follows: 1. Cytochemical studies showed that the activities of $Mg^{++}$-ATPase and succinic dehydrogenase increased with age. However, these enzyme activities were decreased with treatment of chlorambucil, when compared with control group. Interestingly it was observed that chlorambucil treatment increased the activity of acid phosphatase from 6 months upto 18 months, and decreased after 18 months. 2. The lipid peroxide level in myocatdium was increased with age; chlorambucil-treated group was higher than that of control group. 3. Age-dependent increase in activities of monoamine oxidase, xanthine oxidase and catalase was observed. But the increase of catalase activity was higher than that of monoamine oxidase and xanthine oxidase activity in control group. However, in chlorambucil-treated group, age-dependent decrease of these enzyme activities was observed, and catalase activity was more significant particularly with regard to other enzymes. In consequently, the morphological alterationsof myocardium due to chlorambucil treatment was exclusively observed. We demonstrate that this alteration is occured by lipid peroxidation upon chlorambucil treatment.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1532-1536
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• 2015

To investigate the memory-enhancing effect of lactic acid bacteria, we selected the probiotic mixture KF, which consisted of Lactobacillus plantarum KY1032 and Lactobacillus curvatus HY7601 (1 × 10¹¹ CFU/g of each strain), and investigated its antilipidemic and memoryenhancing effects in aged Fischer 344 rats. KF (1 × 10¹⁰ CFU/rat/day), which was administered orally once a day (6 days per week) for 8 weeks, significantly inhibited age-dependent increases of blood triglyceride and reductions of HDL cholesterol (p < 0.05). KF restored agereduced spontaneous alternation in the Y-maze task to 94.4% of that seen in young rats (p < 0.05). KF treatment slightly, but not significantly, shortened the escape latency daily for 4 days. Oral administration of KF restored age-suppressed doublecortin and brain-derived neurotrophic factor expression in aged rats. Orally administered KF suppressed the expression of p16, p53, and cyclooxygenase-2, the phosphorylation of Akt and mTOR, and the activation of NF-κB in the hippocampus of the brain. These findings suggest that KF may ameliorate age-dependent memory deficit and lipidemia by inhibiting NF-κB activation.

• Journal of the Korean housing association
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• v.6 no.1
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• pp.89-101
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• 1995

This study is to analyze dwelling environmental planning in old age of middle age. For this purpose. the data were collected by using questionnaire distributed to 332. The data were analyzed by Chisquare test. The major findings of this research were as follow: 1. In housing plan of old age. they prefer new house .that is not exisiting house. independent house and ordindry housing region in the suburbs of urban. 2. It is 69.3～99 square meter what size of house is suitable for independent life of aged person for living with children. it is 102.3～132 square meter. 3. In the stage of independent or semi-independent life. they want aged couple-independent life. In the stage of dependent life. they want to be cared with children. 4. The garden(madang) is the most important space for age couple in establishing housing plan. They want to amplity life recuperation center and job providing facilities. In old age housing project. they prefer housing type with facility that combine old age house with young age house. According to increasement of dependence. the service support system required flexi-care-system.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.35-50
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• 2007

In this work, optimal harvesting policy for the predator-prey system of three species with age-dependent and diffusion is discussed. Existence and uniqueness of non-negative solution to the system are investigated by using the fixed point theorem. The existence of optimal control strategy is discussed and optimality conditions are obtained. Our results extend some known criteria.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.458-461
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• 2006

Early age cracking of concrete is a widespread and complicated problem, and diverse applications in practical engineering have focused on this issue. Since massive concrete base slab composes the infrastructure of other concrete structures such as pier, concrete dam, and high rise buildings, early age cracking of that is considered as a crucial problem. In this study, finite element analysis (FEA) implemented with the age-dependent microplane model was performed. For a massive concrete base slab, cracking initiation and propagation, and deformation variation were investigated with concrete age. In massive concrete slab, autogenous shrinkage increases the risk of early age cracking and it reduces reinforcement effect on control of early age cracking. Gradual crack occurrence is experienced from exterior surface towards interior of the slab in case of combined hydration heat and autogenous shrinkage. FEA implemented with enhanced microplane model successfully simulates the typical cracking patterns due to edge restraint in concrete base slab.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.451-458
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• 1999

Purpose : To determine normal CT number range of parotid gland by analyzing the change by age increase and the difference among individuals and between both sexes in CT number of normal parotid gland. Materials & Methods : 134 subjects who took the CT scan between the period of Jan. 1996 and Dec. 1997 at Yonsei University, Dental Hospital were selected. Criteria for selection were that the patients must be within the normal range clinically and radiologically, and the entire parotid gland on the axial view must be shown. Among the axial views. the one showing the greatest parotid gland size was selected and its CT number was recorded. Also. CT numbers from both masseter muscle were recorded as its control. Results : There was statistically significant correlation between CT number of right and left of parotid glands and masseter muscles. With the increase of age. there is a significant decrease in the CT number of parotid gland(p<0.05). There was no statistically significant difference in CT number between sexes except the 7th decade and beyond age group of parotid gland(p>0.05). Conclusion : As age increases, CT number of parotid gland has a tendency to decrease, and there is no significant difference in the CT numbers between left and right parotid gland. Therefore in the CT scan of patients suspected of having a salivary gland disease of the parotid gland. to consider normal range of the age-dependent CT numbers of parotid gland and compare the CT numbers of the right and left parotid gland might be useful in diagnosing the disease.

• Journal of Nutrition and Health
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• v.37 no.3
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• pp.210-222
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• 2004

In recent years, the number and proportion of Korean elderly have grown rapidly, and elderly individuals show a disproportionate risk for poor nutritional status. The purpose of this study was to examine the relationship of sociodemographic background to nutrient intake of persons 65 years of age or older, living in 15 cities in Korea. Data on 1973 subjects (603 males, 1370 females), who participated in the Korean Elderly Nutrition Survey (2000), were analyzed. Their mean age was 72.3 years and their mean body mass index (BMI) was 24.2 kg/$m^2$. Basic sociodemographic data were obtained through personal interviews. The 98-item semi-food frequency questionnaire, developed and previously validated for Korean middle-aged and elderly subjects, was administered. “Percentage of subjects who consumed under 75％ Korean RDA,” “number of nutrients consumed below 75％ Korean RDA,” “mean nutrient adequacy ratio,” and “nutrient density” were used to determine nutritional status. Male elderly had better nutritional quality than female elderly. Nutritional quality decreased with age, especially in older elderly (over 75). Elderly who were underweight (BMI 〈 20 kg/$m^2$) showed poorer nutritional quality than those who were normal weight (BMI 20∼25 kg/$m^2$) and overweight (BMI $\geq$ 25 kg/$m^2$). Elderly who lived alone had significantly poorer nutritional quality than those who lived with a spouse, and/or with children. Lower education level and economic dependence also showed lower nutritional quality. A stepwise multiple regression analysis was performed to examine the effects of specific sociodemographic factors on nutritional quality. For number of nutrients under 75％ RDA as a dependent variable, education level explained 4.8％ of the variance, followed by living status, age, body mass index, gender, and living expense support (Model $R^2$ = 0.091). For mean nutrient adequacy ratio as a dependent variable, model $R^2$ was 0.098. Therefore, sociodemographic variables such as gender, age, body mass index, living status, educational level, and economic status influenced elderly nutrition status. These results indicate that an elderly nutrition intervention should focus on subjects who are poorly educated, living alone, age 75 or older, and/or underweight.

• Korean Journal of Exercise Nutrition
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• v.24 no.1
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• pp.9-13
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• 2020

[Purpose] This preliminary study aimed to develop a regression model to estimate the resting metabolic rate (RMR) of young and middle-aged Koreans using various easy-to-measure dependent variables. [Methods] The RMR and the dependent variables for its estimation (e.g. age, height, body mass index, fat-free mass; FFM, fat mass, % body fat, systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure, and resting heart rate) were measured in 53 young (male n = 18, female n = 16) and middle-aged (male n = 5, female n = 14) healthy adults. Statistical analysis was performed to develop an RMR estimation regression model using the stepwise regression method. [Results] We confirmed that FFM and age were important variables in both the regression models based on the regression coefficients. Mean explanatory power of RMR₁ regression models estimated only by FFM was 66.7% (R²) and 66.0% (adjusted R²), while mean standard errors of estimates (SEE) was 219.85 kcal/day. Additionally, mean explanatory power of RMR₂ regression models developed by FFM and age were 70.0% (R²) and 68.8% (adjusted R²), while the mean SEE was 210.64 kcal/day. There was no significant difference between the measured RMR by the canopy method using a metabolic gas analyzer and the predicted RMR by RMR₁ and RMR₂ equations. [Conclusion] This preliminary study developed a regression model to estimate the RMR of young and middle-age healthy Koreans. The regression model was as follows: RMR₁ = 24.383 × FFM + 634.310, RMR₂ = 23.691 × FFM - 5.745 × age + 852.341.

• Computers and Concrete
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• v.34 no.1
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• pp.33-48
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• 2024

This paper presents the detailed experimental and analytical investigation on the evolution of static (E_s) and dynamic modulus of elasticity (E_d) of concrete having 0%, 35%, and 50% FA used as partial cement replacement. Destructive and non-destructive tests were conducted on cylindrical specimens to evaluate the compressive strength and MoE of concrete in compression at the age of 28, 56, 90, and 150 days for all mixes. Experimental results show that the concrete having 35% FA achieved compressive strength and MoE similar to plain concrete at the age of 90 days, while 50% FA concrete attained satisfactory compressive strength and MoE at the age of 150 days. The comprehensive statistical analysis has been carried out in two ways on the basis of the experimental results. Firstly, the 28-day crushing strength of plain concrete in compression was used to design the models for the prediction of E_s and E_d of fly ash concrete at any age and percentage replacement of FA. Secondly, using the values of UPV and RHN, models have been developed to predict the age or time-dependent E_s and E_d of fly ash concrete. These models will be helpful in assessing the E_s and E_d of fly ash concrete without knowing the 28-day crushing strength of plain concrete in compression in the laboratory. Hence, the suggested models in the present study will be beneficial in conducting the health assessment of fly ash based concrete structures.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.68-72
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• 2001

Objective : The goal of this study was to document the influence of the treatment modality(surgery versus endovascular treatment) on the development of chronic shunt-dependent hydrocephalus in a series of 296 patients treated after aneurysmal subarachnoid hemorrhage(SAH). Methods : The following parameters were retrospectively analyzed for association with chronic shunt-dependent hydrocephalus : 1) Age and Sex, 2) Hunt and Hess grade, 3) Fisher computed tomographic grade, 4) aneurysm location, and 5) treatment modality(surgery versus endovascular treatment). Results : Thirty-six of 251 patients(14.3%) who survived the SAH and its neurological and/or medical sequelae underwent definitive shunting for treatment of chronic hydrocephalus. The rate of shunt dependency was positively correlated with a higher age, a higher Hunt and Hess grade, a higher Fisher computed tomographic grade, and aneurysms arising at the anterior communicating artery(p<0.05). Conclusion : The results of the present study indicate that the treatment modality used does not affect the risk of the later development of chronic shunt-dependent hydrocephalus(surgery, 16.2% [25 of 154] ; endovascular treatment, 11.3% [11 of 97] ; p=0.45).