• Polymer(Korea)
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• v.33 no.2
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• pp.158-163
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• 2009

In this study, we synthesized a series of dendritic polystyrene-b-linear poly (t-butyl acrylate) copolymers with well-defined molecular architectures. The hydroxyl group located at the focal point of the second generation dendron bearing polystyrene ($M_n$ = 1000 g/mol) peripheries was converted into amine group via the following stepwise reactions: 1) tosylatoin, 2) azidation, and 3) reduction. On the other hand, the linear poly (t-butyl acrylate)s were prepared by an atom transfer radical polymerization (ATRP) of t-butyl acrylate where benzyl 2-bromopropanoate and Cu(I)Br/PMDETA were used as initiator and catalyst, respectively. To convert the end group of prepared poly (t-butyl acrylate) s into carboxylic acid, a debenzylation was performed using Pd/C catalyst under $H_2$ atmosphere. In the final step, dendritic-linear block copolymers were obtained through a simple amide coupling reaction mediated by 4-(dimethylamino) pyridine(DMAP) and N,N'-diisopropylcarbodiimide(DIPC). The resulting diblock copolymers were shown to have well-defined molecular weights and narrow molecular weight distributions as supported by $^1H$-NMR spectroscopy and gel permeation chromatography(GPC).

• Journal of Korean Medicine for Obesity Research
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• v.3 no.1
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• pp.7-16
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• 2003

Objectives : The lipolytic effects of catecholamines in adipose tissue are mediated by members of adrenergic receptors. This study was conducted to examine the effects of ${\beta}2-AR$ Gln27Glu (Q27E) polymorphism on obesity indices and risk among obesity clinic patients. Methods : 532 subjects, 38 men and 494 women, who attended a weight loss program in a local obesity clinic were analyzed. Height, weight, BMI, WHR and obesity index were measured or calculated. Body composition was measured by bio-impedance analysis. Genotype of ${\beta}2-AR$ polymorphism in codon 27 was analyzed by PCR-RFLP method. Serum concentrations of fasting glucose, total and HDL cholesterol, and triglyceride were determined by autobiochemical analyzer. Results: The Genotype distributions of ${\beta}2-AR$ gene were QQ type 81.3%, QE type 17.9% and EE type 8%. Therefore, the frequency of E allele of ${\beta}2-AR$ gene was 0.170 in the total subjects. The frequency of the ${\beta}2-AR$ variant genotype(QE+EE) was significantly higher in obese group($BMI{\geqq}25$) compared with non-obese group(p=0.027). Weight was significantly higher in variant(QE+EE) type compared with normal(QQ) type in total subjects(p=0.001), male(p=0.022) and female(p=0.013). BMI, obesity index and WHR were also significantly higher in QE+EE type. Body fat man was significantly higher in QE+EE type in total subjects(p=0.005) and female(p=0.027). When forward stepwise regression analysis was used to create a model of risk predictors of obesity($BMI{\geqq}25$), QE+EE type of ${\beta}2-AR$ gene was found to be a significant risk factor for obesity (p=0.042, ORs 1.597). Conclusions: QE+EE genotype of ${\beta}2-AR$ was associated with increased obesity indices and might be a significant risk factor for obesity.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.944-958
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• 2011

Soil hydraulic properties such as hydraulic conductivity or water retention which are costly to measure can be indirectly generated by soil pedotransfer function (PTF) using easily obtainable soil data. The field soil structure description which is routinely recorded could also be used in PTF as an input to reduce the uncertainty. The purposes of this study were to use qualitative morphological soil structure descriptions and soil structural index into PTF and to evaluate their contribution in the prediction of soil hydraulic properties. We transformed categorical morphological descriptions of soil structure into quantitative values using categorical principal component analysis (CATPCA). This approach was tested with a large data set from the US National Pedon Characterization database with the aid of a categorical regression tree analysis. Six different PTFs were used to predict the saturated hydraulic conductivity and those results were averaged to quantify the uncertainty. Quantified morphological description was successively used in multiple linear regression approach to predict the averaged ensemble saturated conductivity. The selected stepwise regression model with only the transformed morphological variables and structural index as predictors predicted the $K_{sat}$ with $r^2$ = 0.48 (p = 0.018), indicating the feasibility of CATPCA approach. In a regression tree analysis, soil structure index and soil texture turned out to be important factors in the prediction of the hydraulic properties. Among structural descriptions size class turned out to be an important grouping parameter in the regression tree. Bulk density, clay content, W33 and structural index explained clusters selected by a two step clustering technique, implying the morphologically described soil structural features are closely related to soil physical as well as hydraulic properties. Although this study provided relatively new method which related soil structure description to soil structure index, the same approach should be tested using a datasets containing the actual measurement of hydraulic properties. More insight on the predictive power of soil structure index to estimate hydraulic properties would be achieved by considering measured the saturated hydraulic conductivity and the soil water retention.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.995-1003
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• 2021

Objective : People are living longer and the elderly population continues to increase. The incidence of degenerative spinal diseases (DSDs) in the elderly population is quite high. Therefore, we are facing more cases of DSD and offering more surgical solutions in geriatric patients. Understanding the significance and association of frailty and central sarcopenia as risk factors for spinal surgery in elderly patients will be helpful in improving surgical outcomes. We conducted a retrospective cohort analysis of prospectively collected data to assess the impact of preoperative central sarcopenia, frailty, and comorbidity on surgical outcome in elderly patients with DSD. Methods : We conducted a retrospective analysis of patients who underwent elective spinal surgery performed from January 1, 2019 to September 30, 2020 at our hospital. We included patients aged 65 and over who underwent surgery on the thoracic or lumbar spine and were diagnosed as DSD. Central sarcopenia was measured by the 50th percentile of psoas : L4 vertebral index (PLVI) using the cross-sectional area of the psoas muscle. We used the Korean version of the fatigue, resistance, ambulation, illnesses, and loss of weight (K-FRAIL) scale to measure frailty. Comorbidity was confirmed and scored using the Charlson Comorbidity Index (CCI). As a tool for measuring surgical outcome, we used the Clavien-Dindo (CD) classification for postoperative complications and the length of stay (LOS). Results : This study included 85 patients (35 males and 50 females). The mean age was 74.05±6.47 years. Using the K-FRAIL scale, four patients were scored as robust, 44 patients were pre-frail and 37 patients were frail. The mean PLVI was 0.61±0.19. According to the CD classification, 50 patients were classified as grade 1, 19 as grade 2, and four as grade 4. The mean LOS was 12.35±8.17 days. Multivariate stepwise regression analysis showed that postoperative complication was significantly associated with surgical invasiveness and K-FRAIL scale. LOS was significantly associated with surgical invasiveness and CCI. K-FRAIL scale showed a significant correlation with CCI and PLVI. Conclusion : The present study demonstrates that frailty, comorbidity, and surgical invasiveness are important risk factors for postoperative complications and LOS in elderly patients with DSD. Preoperative recognition of these factors may be useful for perioperative optimization, risk stratification, and patient counseling.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.325-331
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• 2021

The purpose of this study was to identify the effect of dementia attitudes according to dementia education in university students on the recognition of dementia policy, focusing on the mediating effect of dementia knowledge. The participants were 306, 1~2 grad of students of U and K university in 2 G cities. The data were collected from September 1 to 31, 2017, and analyzed using the SPSS/WIN 21.0 program with t-test, Pearson correlation coefficients and multiple stepwise regression. There were significant differences in the education group compared to the non-education group in recognition of dementia policy, dementia knowledge, and dementia attitude according to the subject's dementia education. The level of dementia attitudes, recognition of dementia policy, dementia knowledge and attitudes were more than moderate. The positive correlations among recognition of dementia policy, dementia knowledge and attitudes were significant. Dementia knowledge was a predictor of recognition of dementia policy (t=2.35, p=019) and showed a significant partial mediating effect, and the explanatory power was 17.8%. It is necessary to continuously systematically provide the development and application of dementia education programs for the whole people to raise correct dementia knowledge, positive attitudes toward dementia, and awareness of dementia policies.

• 한국사회정책
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• v.25 no.4
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• pp.71-104
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• 2018

This paper adopts a distributive performance process model of in-work poverty based on labor markets, households, and welfare states and analyzes the 4-11 waves of the Korean Welfare Panel Study during 2008-15. Previous studies on in-work poverty have focused on the definitions and concepts of in-work poverty by analyzing employment and unemployment persistence and repetition dynamics, but rarely paid attention to institutional distributive performance. In this regard, this study preforms a stepwise analysis of labor markets, households, and welfare states as a process of income generation in labor markets, satisfaction of welfare needs and income pooling at households, and deduction of social security contribution and income tax as well as receipt of public transfer income at welfare states. Results of empirical analysis show that in-work poverty had been on increase during 2008-11, followed by a decrease between 2012-15. At labor market stages, full time status had the most prominent impact on in-work poverty process, while status by employment and contract type have generated a huge variation as well. At household stages, household work intensity and number of earners contributed to reduction of in-work poverty, but the relations did not seen to be straightforward. However, welfare state played little role in lifting employees out of in-work poverty. In terms of institutional distributive process, in-work poverty was prevalent in either household-welfare state stage or labor market-household-welfare stage. Non-vulnerable group in terms of in-risk poverty was around 80% of the sample during the period of analysis, the size of which has remained constant.

• 한국노년학
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• v.38 no.1
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• pp.15-26
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• 2018

This study was aimed to investigate the influencing level of nursing staff's recognition for the health care accreditation on patient safety managing activities by identifying the relationship between them and other factors affecting on patient safety managing activities. Subjects of this study were 182 nursing staffs working in six geriatric hospitals accredited for health care in Seoul metropolitan area. Data was collected during April, 2016 by structured questionnaires. And SPSS/WIN 15.0 program with t-test, ANOVA, Pearson's correlation, and stepwise multiple regression analysis were employed for analyzing them. 96.2% of the subjects have recognized the accreditation and 31.8% of them have acknowledge it in detail. The average level of recognition for the health care accreditation and patient safety managing activity were 3.60 and 4.39 point (max.5.0) respectively. Correlation between them was positive(r=.339, p<.001). Significant factors influencing patient safety managing activity were internal service quality promotion (t=5.292, p<.001) and academic background (t=2.836, p=.005). Education program or information on health care accreditation system, and action plans for promoting internal service quality for the nursing staffs including job standardization of the jobs are recommended for the better patient safety managing activities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.232-241
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• 2019

This study examines one of the conventional and controversial issues in modern finance. Specifically, this study identifies financial determinants of corporate R&D intensity for firms belonging to Korean Chaebols. Empirical estimation procedures are applied to derive more robust results of each hypothesis test. Static panel data, Tobit regression and stepwise regression models are employed to obtain significant financial factors of R&D expenditures, while logit, probit and complementary log-log regression models are used to detect financial differences between Chaebol firms and their counterparts not classified as Chaebols. Study results found the level of R&D intensity in the prior fiscal year, market-value based leverage ratio and firm size empirically showed their significance to account for corporate R&D intensity in the first hypothesis test, whereas the majority of explanatory variables had important power on a relative basis. Assuming that the current circumstances in the domestic capital market may necessitate gradual changes of Korean Chaebols in terms of their socio-economic function, the results of this study are expected to contribute to identifying financial antecedents that can be beneficial to attain optimal level of corporate R&D expenditures for Chaebol firms on a virtuous cycle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.411-420
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• 2018

This study was conducted to identify the effects of interpersonal communication between health care providers after receiving supplementary education. The participants of this study were 433 health care providers who work at 29 general hospitals in Gwangju Metropolitan City and Jeollanamdo Province. Data were collected from June 8 to June 25, 2018 and evaluated by t-tests, dispersion analysis, correlation analysis and stepwise regression. The results were produced by investigating interpersonal communications according to socio-demographic and health-related characteristics including age, education level, bed size of the hospital at which the participant worked, job satisfaction, hospital location, personal health status, experience with health care management and experience with depression. There were significant differences in communication observed according to supplemental education awareness regarding age, bed size of hospital, occupation, wage, type of medical institution of employment, job satisfaction, work location, health status, health care education experience and chronic disease. There were positive correlations between supplemental education awareness in health workers and their interpersonal communication. The factors that had positive effects on interpersonal communication were level of education and health-related education experience, while age, hospital bed size and job dissatisfaction had negative effects. Finally, support environment, learning transfer and results were identified as sub-factors of supplemental education. Based on the results above, it was proposed that educational training to enhance results, provide a supportive environment and foster learning transfer be developed to increase communication between health workers and provide a safe health service for patients.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.467-477
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• 2019

The purpose of this study was to investigate the relationship among job stress, nursing organizational culture, emotional exhaustion for the clinical nurses and the influencing factors on retention intention of nurses in a general hospital. This study used 209 questionnaires from nurses in B city to collect data from November 1, 2017 to December 15. Data were analyzed by SPSS 20.0 program using descriptive statistics, t-test, ANOVA, Scheffe's test, Pearson's correlation coefficient and Stepwise Multiple Regression. The results are as follows; The participants' job stress level was 3.48(${\pm}0.46$), nursing organizational culture level was 3.13(${\pm}0.31$), emotional exhaustion level was 3.95(${\pm}1.18$) and retention intention level was 4.54(${\pm}1.29$). Retention intention was a significant correlated between job stress(r=-21, p=.003), nursing organizational culture(r=.25, p<.001), emotional exhaustion(r=-40, p<.001). According to the result of multiple regression analysis, The significant factors influencing retention intention of clinical nurses were emotional exhaustion, nursing organizational culture, total career and age. it was explained by 23.7%. Based on these findings, in order to increase the level of retention intention, it is necessary to develop a variety of programs to reduce emotional exhaustion, as well as a plan to help them recognize a positive nursing organization culture, and to fine ways to manage long-term careers.