• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.91-101
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• 2001

It has been shown that the multiple trees predictors are more accurate in reducing test set error than a single tree predictor. There are two ways of generating multiple trees. One is to generate modified training sets by resampling the original training set, and then construct trees. It is known that arcing algorithm is efficient. The other is to perturb randomly the working split at each node from a list of best splits, which is expected to generate reasonably good trees for the original training set. We propose a new combined multiple regression trees predictor which uses the latter multiple regression tree predictor as a predictor based on a modified training set at each stage of arcing. The efficiency of those prediction methods are compared by applying to high throughput screening of chemical compounds for biological effects.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.6
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• pp.349-354
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• 2006

The aromatic hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the biological and toxicological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and related chemicals. The application of recombinant reporter plasmid such as the firefly luciferase gene has proven to be a very effective method to detect these chemicals. The bioassay system, CALUX, is sensitive in directly detecting AhR-agonists from a variety of environmental and biologic materials. However, responses of the AhR-dependent bioassays are dependent on the cell types used. Thus, we developed a sensitive bioassay using the recombinant mouse hepatoma cell (Hepa1c1c7) for the determination of dioxins. The recombinant cell line was stably transfected with firefly luciferase reporter gene (pGudLuc1.1). The transfected cells showed the highest induction of luciferase activity at 4.5 hr and a decrease beyond this time point. The system showed the highest sensitivity of detection ever reported. Upon TCDD exposure cells showed 2 fold increase at 10 pM and 7 fold increase at 100 pM, respectively. The passage number after the transfection played an important role in the sensitivity. The increase of passage number tended to increase the sensitivity of the cells up to 15. The media without phenol red showed a higher induction rate than with phenol red, suggesting the preferable use of phenol red-free media for the bioassay. Since each of the assays has unique characteristics that make them suitable for some screening applications and not others, development of sensitive bioanalytical methods based on a variety of cellular systems in a key to the successful determination of dioxins. The bioassay system developed in this study will contribute to further development of successful screening the AhR agonists among the environmental mixture. In addition, the rapid and sensitive nature of this cellular system can be applied as a valuable tool to screen the dioxin-like moieties among the prodrugs at the initial stage, thereby expediting the new drug discovery.

• Mycobiology
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• v.44 no.3
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• pp.171-179
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• 2016

In the screening of marine mangrove derived fungi for lovastatin productivity, endophytic Aspergillus luchuensis MERV10 exhibited the highest lovastatin productivity (9.5 mg/gds) in solid state fermentation (SSF) using rice bran. Aspergillus luchuensis MERV10 was used as the parental strain in which to induce genetic variabilities after application of different mixtures as well as doses of mutagens followed by three successive rounds of genome shuffling. Four potent mutants, UN6, UN28, NE11, and NE23, with lovastatin productivity equal to 2.0-, 2.11-, 1.95-, and 2.11-fold higher than the parental strain, respectively, were applied for three rounds of genome shuffling as the initial mutants. Four hereditarily stable recombinants (F3/3, F3/7, F3/9, and F3/13) were obtained with lovastatin productivity equal to 50.8, 57.0, 49.7, and 51.0 mg/gds, respectively. Recombinant strain F3/7 yielded 57.0 mg/gds of lovastatin, which is 6-fold and 2.85-fold higher, respectively, than the initial parental strain and the highest mutants UN28 and NE23. It was therefore selected for the optimization of lovastatin production through improvement of SSF parameters. Lovastatin productivity was increased 32-fold through strain improvement methods, including mutations and three successive rounds of genome shuffling followed by optimizing SSF factors.

• Journal of Korean Biological Nursing Science
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• v.15 no.4
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• pp.219-229
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• 2013

Purpose: The purpose of this study was to identify the prevalence of osteoarthritis and its risk factors among a community dwelling population age 60-74 and 75 and over (young-old vs. old-old) in Korea. Methods: A total of 1,389 of age 60-74 and 397 of age 75 and over from the 2010 Korean National Health and Nutrition Examination Survey (KNHANES) were selected. The data analysis was performed using the complex sampling function of SPSS version 19.0. Results: The prevalence of osteoarthritis was greater for old-old people (35.50%) compared to young-old people (18.20%). Univariate logistic regression analysis shows that the difference of risk factors for osteoarthritis between young-old and old-old elderly people. The prevalence of osteoarthritis in young-old people was associated with lower education levels; performance of moderate intensity physical activity; higher waist circumference, whereas old-old people was most affected in females; depression and experience. Conclusion: The finding of differences in the prevalence of osteoarthritis and its' risk factors between young-old and old-old people is expected to promote the screening strategy for the aged at risk of osteoarthritis in the Korean community.

• Journal of Korean Biological Nursing Science
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• v.14 no.4
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• pp.282-290
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• 2012

Purpose: The purpose of this study was to identify the prevalence of hypertension and its risk factors among community dwelling aged 65 and over in South Korea. Methods: A total of 1,367 subjects from the 2010 Korean National Health and Nutrition Examination Survey (KNHANES) were selected. The data analysis was conducted by SPSS WIN 19.0 using descriptive statistics, ${\chi}^2$-test, and logistic regression analysis. Results: The prevalence of hypertension was found to be 47.70%. Logistic regression analysis shows that hypertension was more prevalent as people became older; in females; in elderly who were not employed as compared to those employed; elderly with diabetes, and obesity as compared to those without these health conditions; as elderly who performed more moderate intensity exercise. While, education, household income, high risk alcoholic drinking, smoking, stress perception, usual activity, and eating out behavior were not associated with prevalence of hypertension in this study. Conclusion: The finding of prevalence of hypertension and its risk factors is expected to promote the screening or prevention strategy for community dwelling aged 65 and over at risk of hypertension in Korea.

• Journal of Korean Biological Nursing Science
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• v.14 no.4
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• pp.231-238
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• 2012

Purpose: The purpose of this study was to investigate body composition, blood pressure, blood lipids, and glucose according to obesity degree by body fat percentage in female university students. Methods: A total of 231 subjects were participated between July and December 2010. The anthropometric measures and blood analyzer were used. Data were analyzed using descriptive statistics, ANOVA, and Pearson's correlation coefficient with SPSS 18.0. Results: Percentage of body fat (PBF)-defined obesity had higher prevalence than body mass index (BMI)-defined obesity. Weight, BMI, PBF, fat mass, Waist to hip ratio (WHR), Systolic blood pressure (SBP), Diastolic blood pressure (DBP) in obesity group were higher than normal group and Soft lean mass and Low density lipoprotein (LDL) in obesity group were lower than normal group. There were significant correlations between PFB, SBP, DBP, Triglyceride (TC), High density lipoprotein (HDL), and LDL. Conclusion: In conclusion, when screening for obesity in female university students, body fat should be considered. It is needed to develop obesity management program according to obesity degree and to identify the effectiveness.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.44-52
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• 2006

New organotin(IV) derivatives with general formulae R_2SnL_2 and R_3SnL, where R = methyl, n-butyl, n-octyl and phenyl and HL is either 3-[N-(4-nitrophenyl)amido]-propenoic acid or 3-[N-(4-nitrophenyl)amido] propanoic acid have been synthesized in 1 : 2 and 1 : 1 molar ratio by different methods. The FTIR spectra clearly demonstrated that the organotin(IV) moieties react with [O,O] atoms of the ligands. The bonding and coordination behavior in these complexes are discussed on the basis of multinuclear (^1H,\,^{13}C,\,^{119}Sn) NMR and mass spectrometric studies. Antibacterial, and antifungal screening tests were performed for these compounds and reported here. These values were compared to those of the precursors and it was found that diorganotin(IV) complexes exhibit less activity as compared to triorganotin(IV) complexes . LD_{50} data were obtained by Brine Shrimp assay method. Insecticidal activity was performed for selective compounds by contact toxicity method.

• Journal of Korean Biological Nursing Science
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• v.25 no.4
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• pp.229-242
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• 2023

Purpose: The electronic frailty index (eFI), which is derived from electronic health records, has been recommended as screening tool for frailty due to its accessibility and ease of use. The objective of this systematic review was to identify the prevalence of frailty assessed by the eFI and its influence on health outcomes in older adults with chronic diseases. Methods: We searched PubMed, Embase, Web of Science, CINAHL, SCOPUS, Cochrane, Google search, and nursing journals in Korean from January 2016 to December 2022. Results: Twelve studies were analyzed. The eFI score, based on routine clinical data, was associated with adverse health outcomes. The most frequent outcome studied was mortality, and the eFI was associated with increased mortality in nine studies. Other outcomes studied included hospitalization, length of stay, readmission, and institutionalization in relation to hospital care usage, and cardiovascular events, stroke, GI bleeding, falls, and instrumental activities of daily life as health conditions. Conclusion: Early identification of frailty in older adults with chronic diseases can decrease the burden of disease and adverse health outcomes. The eFI has a good discriminative capacity to identify frail older adults with chronic diseases.

• Environmental Mutagens and Carcinogens
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• v.24 no.3
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• pp.137-142
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• 2004

Dioxin-like compounds are ubiquitous environmental polltants that could be accumulated in biological system and toxic to human and wildlife. Given this issue, it is important to develop a reliable dioxin detection methods for a rational risk assesment of dioxin-like compounds. In this study, we tried to set up and validate a sensitive, reliable risk assessment of dioxin-like compounds. In this study, we tried to set up and validate a sensitive, reliable and rapid bioassay model, CALUX bioassay as a screening tool for routine measurement of dioxin-like conpounds in environmental matrices. For the valisation of CALUX bioassay, firstly, we performed dose-response assay for 2,3,7,8-TCDD, most potent dioxin-like compound, using two different methods CALUX and EROD assay. Induction of luciferase activity and CYPIA catalyzed EROD activity were dose-dependently induced by 2,3,7,8-TCDD, with initial induction at 0.1 pM and maximal induction at 1 nM. In order t determine whether the CALUX bioassay could predict the effects of dioxin-like compounds, 2,3,7,8-TCDD dose-response from CALUX was compared with that from EROD assay. The correlation coefficient ($r^2$) was found to be 0.89, indicating a good correlation between two different methods and the possibility of CALUX bioassay as a useful dioxin detecting method.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.363-367
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• 1996

In general, the physiological systems have shown nonlinear complex phenomena. This study analyzes nonlinear characteristics of the flow of peripheral blood vessel dynamics in physiological systems using chaos theory. We performed this study by means of several quantity methods and power spectrum. The quantity methods are a phase space reconstruction and a poincare's map. And the power spectrum method is a conventional linear analysis. Experimental data have been acquired from examining 10 diabetic patients, and 10 control subjects in initial stable state. In acquisition experminetal data, we anlysized the differences of nonlinear characteristics between diabetic group and control group. The results of quality analysis methods showed the flow of peripheral blood vessel had the nonlinear and chaotic characteristics, screening a strange attractor on reconstructed phase space. In conclusion, the flow dynamics of peripheral blood vessel had a chaotic behavior of nonlinear dynamic systems, dynamic system, and differences of characteristic of nonlinear dynamic system.