• Polymer(Korea)
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• v.38 no.3
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• pp.333-337
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• 2014

PVC (polyvinyl chloride) intravenous fluid bags and tubes that contain DEHP (diethylhexyl phthalate) as a plasticizer have several associated disadvantages for intravenous injections. We investigated the drug absorption behaviors on the inner surface of an infusion tube that consisted of commercialized PVC/PU (polyurethane). We developed a non-PVC (polyolefin) tube in order to improve the efficacy of this drug administration method. We prepared four types of non-PVC (polyolefin) infusion tubes using a polyethylene (PE), polypropylene (PP), syndiotactic 1,2-polybutadiene (PB), and styrene-ethylene (SE) copolymer elastomers were prepared using a single screw extruder. The four types of manufactured non-PVC (polyolefin) infusion tubes had good mechanical properties that were equivalent to PVC tube properties. The four types of prepared non-PVC (polyolefin) infusion tubes also prohibited drug absorption when compared to the commercialized PVC and PU tubes. Therefore, based on the results of this study, prepared non-PVC (polyolefin) tubes are good candidates for infusion because they prevent drug absorption and the release of DEHP.

• Management & Information Systems Review
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• v.35 no.2
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• pp.273-284
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• 2016

The objective of this study is to analyze the market efficiency in the futures markets. Although many previous studies have investigated market efficiency between spot and futures prices, that with different maturities has not been studied in the futures markets extensively. For our objective, this paper examines KOSPI200 stock index future market with different maturities. We analyze the dynamic serial relationship of the difference of basis between nearest-month contract and next nearest-month contract using dynamic regression analysis suggested by Kawamoto and Hamori(2011) Using the data from 2000. 1 to 2013. 12, the major empirical findings are as follows: First. the mean and standard deviation of basis of next nearest-month contract is bigger than those of nearest-month contract. Second, the t-period basis of nearest-month contract can be explained by (t-1)period basis of that. Third, the basis spread of t-period and (t-1)period have negative affect on the return of underlying assets. This result is very reasonable because two basis spreads are derived from same underlying assets. Finally, basis information of next nearest-month contract can be used for the prediction of nearest-month contract and spot market return.

• Management & Information Systems Review
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• v.31 no.3
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• pp.307-321
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• 2012

This paper examines the spillover effect between Korea stock market and Chinese stock market according to increasing economic power of Chinese. Chinese stock market start the transaction one hour and half early than Korea stock market. Especially we focuses the response of Korea stock market after Chinese stock market starts. So we analyze the return an volatility of Korea stock market after 10:30. We employee daily and intraday stock return and volatility. The sample period ranges from January 2008 to April 2010 total 28 months. Our results show that the gap of open price between Korea and Chinese stock market affect the five minute return and volatility of Korea stock market but don't affect the ten minute return and volatility. Recently, this spillover effect has increased more and more. This shows the rapid increase of economic power of Chinese to affect the Korea capital market.

• Journal of agricultural medicine and community health
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• v.34 no.2
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• pp.223-233
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• 2009

Objectives: This study aimed to examine the relations between exposure to anti-smoking promotion media and smoking, targeting middle school students who were exposed to various media of promotion. Methods: The subjects of the study were 38,820 middle school students who answered to the 2007 Korea Youth Risk Behavior Web-based Survey. Answers of 37,714 subjects were used for the final analysis except those of 1,106 that could not be used to judge anti-smoking promotion media and prevalence of smoking as they were considered insincere to the questions. We used SPSS of version 17.0. This study conducted a chi-square test to identify smoking rate according to characteristics of subjects and a multivariate logistic regression analysis to identify whether they are independently significant. Results: Smoking rate increased as the subjects were in higher grades. From the results of multivariate logistic regression, odds ratio(OR) at points 5~6 of the first graders that had never been exposed to anti-smoking promotion media was 0.49(95% CI=0.33-0.74), which was significantly low. And OR at points 5~6 of the third graders was 0.57(95% CI=0.43-0.76), significantly low. Conclusions: This study identified the relations between exposure to anti-smoking promotion media and smoking of middle school students in Korea.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.705-713
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• 2004

The objectives of this study were to evaluate the fluoride release and the change of surface roughness of fluoride releasing restorative materials after toothbrush-dentifrice abrasion. Seven commercially available fluoride releasing restorative materials (Fuji II LC Improved: FL, Compoglass F: CG, Dyract AP: DR, F2000: FT, Ariston: AT, Tetric: TR, and Gradia: GD) were selected as experimental materials. The results obtained were summarized as follows: 1. The AT, FL, and CF groups produce an initially large burst of fluoride release and comparatively low but continuous release of fluoride. But other groups produce no initial burst of fluoride and levels of release remain relatively constant. 2. The rate of fluoride release remains steady state after 40 days. The results of Tukey's test (P<.05), the fluoride release showed the order of decreasing rank as follows: AT > FL > compomers > TC and GD. 3. The surface roughness indicated that the highest value was observed in the FT group and the lowest value was observed in the CF group. The surface roughness of Tukey's test showed the significant differences between groups of FT, AT and FL and groups of CF, DR, GD and TC (P<0.05).

• The Journal of Society for e-Business Studies
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• v.18 no.1
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• pp.71-95
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• 2013

This study aims to validate the cost of building the infrastructure to commercialize online electric vehicles. For that purpose, we probe the cost to construct the necessary infrastructure for online electric vehicles regarding Seoul area public bus transit. OLEV and PEV are considered as alternative electric vehicle schemes, and each of them has their own cons and pros in terms of rechargeable battery cost and charger cost. An optimization model which minimizes the cost to install online electric bus feeding devices is proposed in order to compare the total costs of the two alternative schemes. We developed a Mixed Integer Programming model to locate the feeding devices of several different lengths at each bus stops. Furthermore, we implemented a computer simulator to obtain the parameters which will be used in the MIP model and a Web-based system which determines the optimal location of infrastructure for the whole city area from a result of the MIP model. The cost comparison result shows that the total cost of OLEV is cheaper than that of PEV considering the real data of Seoul area public transit, and, as a result, confirms the feasibility of the commercialization of OLEV.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1067-1072
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• 2003

The electrical stability of the varistor ceramics composed of Zn-Pr-Co-Cr-Dy oxides-based varistors was investigated at 0.0∼2.0 mol% Dy$_2$O$_3$ content under DC accelerated aging stress. The ceramic density was increased up to 0.5 mol% Dy$_2$O$_3$ whereas further addition of Dy$_2$O$_3$ decreased sintered ceramic density. The density sailently affected the stability due to the variation of conduction path. The nonlinearity of varistor ceramics was greatly improved above 45 in the nonlinear exponent and below nearly 1.0 ${\mu}$A by incorporating Dy$_2$O$_3$. Under 0.95 V$\_$1mA/150$^{\circ}C$/24 h stress state, the varistor ceramics doped with 0.5 mol% Dy$_2$O$_3$ exhibited the highest electrical stability, in which the variation rates of varistor voltage, nonlinear exponent, and leakage current were -0.9%, -14.4%, and +483.3%, respectively. The variation rates of relative permittivity and dissipation factor were +7.1% and +315.4%, respectively. The varistors with further addition of Dy$_2$O$_3$ exhibited very unstable state resulting in the thermal runaway due to low density.

• Journal of Embryo Transfer
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• v.14 no.3
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• pp.203-210
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• 1999

In this stuyd, the effect of the dominant follicle aspiration for the superovulatory response in HanWoo was investigated. The criterion for the presence or absence of a dominant follicle based on their morphological examination. The dominant follicle was aspirated 48hr before the onset of superovulation treatment by 6.5MHz convex probe connected with a carrier and superovulation induced by FSH (Super-Ov Tyrer, Texas, U.S.A) adminstered twic a day s.c. over 4 day in a decreasing regimen. From 13 HanWoo scanned daily to determine the presence and growth of the dominant follicle, its an average diameter of 15.4mm was measured and an average diameter of corpora lutea was 18.7mm on day of follicular aspiration. In the experiment, a follicular remove by ultrasound-guided aspiration, the ovarian response was significantly enhanced when animals were superovulated in the aspiation of a dominant follicle compare with animals superovulated non-aspiration of a dominat follicle. In the aspiration of a dominant follicle donors yieleded more corpora lutea(14.4$\pm$4.7 vs 8.6$\pm$3.4) and transferable embryos(8.9$\pm$4.2 vs 5.4$\pm$2.7) than control. In cows in which the dominant follicle had been aspirated under sonographical control 2 days before superovuation, the number of corpus lutea and transferable embryos were significantly enhanced compared with animals superovulated in the presence of a dominant follicle (14.4$\pm$4.7 vs 6.9$\pm$2.7, ; 8.9$\pm$4.2 vs 3.3$\pm$1.6). After 7 days of artificial insemination, the embryos at 7 days were cllected by uterine flushing after dominant follicle insemination, the embryos at 7 days were collected by uterine flushing after dominant follicle aspiration and superovulation treatment, and evaluated their quality by morphological criteria. Sixteen embryos with excellent and good grade were transferred into 8 recipient cows. Six pregnancies were identified at 60 and 120 days of gestation by rectal palpations. In conclusion, the present study showed that 1) the presence or absence of a dominant follicle signficicnatly affects superovulatory responses, and 2) ultrasound-guided follicular aspiration of the dominant follicle and superovuation treatment provides an accurate and procedure to increase ovarian responses in HanWoo.

• Journal of Korean society of Dental Hygiene
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• v.17 no.5
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• pp.791-803
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• 2017

Objectives: Oral health management is important to improve the quality of life among the elderly. This study investigated the performance of elderly oral health management among some care workers in long-term-care hospitals. Methods: The study subjects were 174 care workers in 10 long-term-care hospitals. Data on general characteristics of care workers, attitude, recognition and knowledge of elderly health, performance of elderly oral health management were collected by a self-administered questionnaire. Data were analyzed through descriptive analysis, t-test, ANOVA, correlation and multiple regression analysis by using a SPSS version 23.0 statistical program. Results: The performance score of oral health management was $4.34{\pm}0.64$ on the 5-point Likert scale. The subjects who exercised more than 2 times a month were significantly higher in their performance of elderly oral health management compared to subjects who did not exercise (${\beta}=0.232$, p=0.035). And, the subjects who cared 10-19 persons were significantly higher in performance of elderly oral health management compared to subjects who cared more than 20 elderly (${\beta}=0.246$, p=0.020). The oral health behavior of care worker (${\beta}=0.271$, p<0.001) and the knowledge of oral health care (${\beta}=0.055$, p=0.008) were positively related to the performance of elderly oral health management. Conclusions: The educational program designed to improve knowledge of care workers in accordance with the standard textbook for training care workers should be developed, and the long term education program should be reinforced to improve the performance for elderly oral health care. If care workers can care a proper number of old persons, they will give oral health care to them.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.2
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• pp.25-32
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• 2004

Purpose : The simulator is used to determine patient field and ensure the treatment field, which encompasses the required anatomy during patient normal movement such as during breathing. The latest simulator provide real time display of still, flouroscopic and digitalized image, but conventional simulator is not yet. The purpose of this study is to introduce digital image capture system(DICS) using conventional simulator and clinical case using digital captured still and flouroscopic image. Methods and materials : We connect the video signal cable to the video terminal in the back up of simulator monitor, and connect the video jack to the A/D converter. After connection between the converter jack and computer, We can acquire still image and record flouroscopic image with operating image capture program. The data created with this system can be used in patient treatment, and modified for verification by using image processing software. (j.e. photoshop, paintshop) Result : DICS was able to establish easy and economical procedure. DCIS image was helpful for simulation. DICS imaging was powerful tool in the evaluation of the department specific patient positioning. Conclusion : Because the commercialized simulator based of digital capture is very expensive, it is not easily to establish DICS simulator in the most hospital. DICS using conventional simulator enable to utilize the practical use of image equal to high cost digitalized simulator and to research many clinical cases in case of using other software program.