• Journal of the Korean earth science society
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• v.27 no.1
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• pp.73-82
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• 2006

Dust samples were collected from 10 middle and high schools in the Gochang-Gun, Korea. Heavy metal concentrations were determined for the dry-deposited dusts from indoor and outdoor of classroom and playground of each sampling site. Concentrations of Cd, Cu, Pb and Zn in indoor's dusts were highly concentrated. Also concentrations of Cu, Ni, Pb and Zn in outdoor's dusts were highly concentrated. Concentrations of Cd, Cu and Zn in the dusts were much higher than the world average contents in soil and environmental orientation value. These levels are similar to those of the dust samples at middle schools and high schools located in Jeonju-city, Korea. Compared with concentrations of heavy metals in soils and dusts in Korea, the environment of indoor and outdoor of classroom is highly concentrated except for Cu, Zn. The concentrations of playground is less than that of residential dust and main road dust and playground in Jeonju-city. Playground dusts in 1 school exhibited the enhanced heavy metal pollution with a pollution index (Kloke, 1979) greater than 1.0, but indoor and outdoor dusts in 7 schools exhibited the enhanced heavy metal pollution with a pollution index (by Kloke) yester than 1.0.

• Journal of Gastric Cancer
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• v.17 no.1
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• pp.52-62
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• 2017

Purpose: The Trastuzumab for gastric cancer (GC) trial identified human epidermal growth factor receptor 2 (HER2) as a predictor of successful treatment with trastuzumab (HER2 receptor targeting agent) among patients with advanced/metastatic GC. To date, the prevalence of HER2 overexpression in the Korean population is unknown. The present study aimed to assess the incidence of HER2 positivity among GC and gastroesophageal (GE) junction cancer samples and the relationship between HER2 overexpression and clinicopathological characteristics in Korean patients. Materials and Methods: Tumor samples collected from 1,695 patients with histologically proven GC or GE junction enrolled at 14 different hospitals in Korea were examined. After gathering clinicopathological data of all patients, HER2 status was assessed by immunohistochemistry (IHC) at each hospital, and IHC 2+ cases were subjected to silver-enhanced in situ hybridization at 3 central laboratories. Results: A total of 182 specimens tested positive for HER2, whereas 1,505 tested negative. Therefore, the overall HER2-positive rate in this study was 10.8% (95% confidence interval=9.3%-12.3%). The HER2-positive rate was higher among intestinal-type cases (17.6%) than among other types, and was higher among patients older than 70 years and 50 years of age, compared to other age groups. Conclusions: Our evaluation of the HER2 positivity rate (10.8%) among Korean patients with GC and GE junction indicated the necessity of epidemiological data when conducting studies related to HER2 expression in GC and GE junction.

• Journal of Periodontal and Implant Science
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• v.30 no.3
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• pp.491-504
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• 2000

In clinical therapy, the current goal of dental implants is to enhance quantity and quality of osseointegration. Surface roughness and oxide structure are considered to influence the behavior of adherent cells. The purpose of this study is to evaluate the effect of different surface treatment on cellular response. The attachment and proliferation of osteoblast-like cell on sandblasted, sandblasted and etched, thermal oxidated surfaces have been compared. Sandblasting was done with $Al_2O_3$ particles(grain size of $50{\mu}m$), etching was processed with $NH_4OH$ : $H_2O_2$ : $H_2O(1:1:5)$ at $90^{\circ}C$ for 1 minute. Thermal oxidation was followed sandblasting and etching at $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$ for 2 hours. Measurement of surface roughness after the different treatment did not show any differences of Ra value between terated surfaces. Cell attachment and proliferation were increased during experiment period, but no difference was observed. SEM evaluation revealed a similar pattern of osteoblast-like cells, well attached with dendritic extension and producing numerous matrix vesicles on cell surface. The results of this study showed that oxide layer alteration by thermal oxidation did not affect the attachment and proliferation of osteoblast-like cells. This suggests the possibility that the cellular responses are further influenced by surface roughness than titaniun oxide structure.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.20-28
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• 2014

The high velocity oxygen fuel spraying (HVOF) is a kind of surface modification process technology to form the sprayed coating layer after spraying the powder to molten or semi-molten state by the ultra-high speed at the high-temperature heat source and conflicting with a substrate. It is desirable to melt completely the thermal spray powder in order to produce the coating layer with an optimal adhesion, however, because a semi-molten powder in a spray process has the low efficiency and become a factor that degrades the mechanical property by the inducement of pore-forming within the coating layer. To improve the wear resistance, corrosion resistance and heat resistance, in this study, the plungers of high-speed and ultra-high pressure reciprocating hydraulic pumps for oil and water used in ironwork are produced with $420J_2$ and the coating layers of plungers are formed by the powders of WC-Co-Cr and WC-Cr-Ni including the high hardness WC. The surface of these plungers is modified by the super-mirror face grinding machine using variable air pressure developed in this laboratory, and then the characteristics of cross-sectional microstructure, and surface roughness and hardness values between no operation and 100 days-operation are examined and made a comparison. The fine tops and bottoms on surface roughness curve of oil-hydraulic pump plunger sprayed by WC-Cr-Ni are molded more and higher than those of water-hydraulic pump sprayed by WC-Co-Cr because the plunger diameter of oil-hydraulic pump is 0.4 times smaller than that of water-hydraulic pump and the pressure of oil-hydraulic pump exerted on the plunger is operated with the 70 bars higher than that of water-hydraulic pump. As a result, it is found that the values of centerline average surface roughness and maximum height for oil-hydraulic pump plunger are bigger than those of water-hydraulic pump plunger.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.403-407
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• 2011

A form of polycystic ovary (PCO) resembling some aspects of the human PCO syndrome (PCOS) can be induced in rats by a single injection of estradiol valerate (EV). An increase in sympathetic outflow to the ovary precedes, by several weeks, the appearance of cysts, suggesting the involvement of a neurogenic component in the pathology of this ovarian dysfunction. To test the hypotheses that the change in sympathetic tone is related to an augmented production of hippocampal and/or ovarian nerve growth factor (NGF), and that this abnormally elevated production of NGF contributes to the induction of PCOS induced by EV. The animals were sacrificed after PCOS induction and the ovaries and hippocampus were sectioned and compared to the normal control. The expression of NGF was measured by immunohistochemical staining and Western blot analysis in the ovaries and hippocampus. EV-induced PCOS showed significant increase of ovarian NGF expression. Immunohistochemical expression of NGF was confined to the follicular cells and interstitial cells. Hippocampal NGF expression was not significantly changed. In conclusion EV-induced PCOS was related to the ovarian sympathetic activation which was mediated by NGF.

• Journal of Ginseng Research
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• v.35 no.3
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• pp.360-367
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• 2011

In this study, we investigated the effects of total ginseng saponin (TGS) on the cutaneous wound healing process using histological analysis. A total of 24 ICR mice, 5-weeks-old, were used for all in vivo experiments. Mice were divided into control and TGS-treated groups and four equidistant 1-cm full-thickness dorsal incisional wounds were created. The wounds were extracted at days 1, 3, 5, and 7 post-injury for histomorphometrical analysis including wound area and contracture measurements, keratinocyte migration rate, and calculation of infiltrating inflammatory cells. The results showed that the wound area was smaller and keratinocyte migration rate was higher in the TGS-treated group than that of the control group from days 3 to 7. Inflammatory cells in the TGS-treated group at days 1 and 3 were reduced compared to the control group. Wound contraction in the TGS-treated group was greater than in the control group on days 3 to 5, and collagen deposition in the TGS-treated group was higher than in the control group during wound healing. The results indicate a beneficial effect of TGS when used to treat skin wounds.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.183-194
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• 2020

Recently, in Korea, financial institutions such as banks are most severely affected by the universalization of the Internet and smartphones. On the other hand, the use of online systems by financial institutions keeps increasing; the convenience of online services has a significant influence on the attraction and the retention of financial customers; consumer needs are also diversely expressed. This paper deduces from the precedent researches a mechanism that online financial system enhances the trust of customers -the medium of the online system and other customers- and its perceived easiness affects its perceived effectiveness and then all these internal variables induce satisfaction. Plus, this paper aims at verification of the hypothesis in terms of an extended technology acceptance model, based on the hypothesis that word of mouth and repurchase are significantly linked to this mechanism. Through this study, the researchers tried to check how the online service quality and emotional factors of financial institutions affect the users in accordance with the trend of changes in the service usage method of financial institutions, and confirmed that the hypothesis was not rejected.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6694-6701
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• 2014

The aim of this study was to identify the correlation between low density lipoprotein (LDL) cholesterol and the pulmonary function. This study enrolled premenopausal women in their aged 40s, who visited the health promotion center of a general hospital more than two times. A total of 384 subjects were classified into four groups based on their LDL-cholesterol levels; A, LDL(mg/dL)<100 at both initial and follow-up; B, LDL<100 at initial but ${\geq}100$ at follow-up; C, $LDL{\geq}100$ at initial but <100 on follow-up; and D, $LDL{\geq}100$ at both the initial and follow-up test. The result showed no significant differences in the pulmonary function between the four groups. Multiple linear regression analysis, which was adjusted for age, body mass index, smoking, exercise, and follow-up duration, showed a significant negative relationship between the changes in the LDL and the changes in the $FEV_1/FVC$ (${\beta}=-0.109$, S.E.=0.029, P<0.001), but not in the $FEV_1$ and FVC. In conclusion, there was a significant but weak relationship between the LDL and pulmonary function. Further larger studies will be needed.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.26-37
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• 2009

Recently rapid environmental changes due to desertification and industrialization in China make a threat to Korea, especially during Asian Dust Event (ADE). This study was aimed to compare symptoms and behaviors related to ADE between Korea and China. We conducted questionnaires on self-reported symptoms and behaviors before and during ADE. Korean and Chinese subjects were grouped into children, adults, and elderly by nation (n=791). Statistical analyses were performed by $X^2$-test, Fisher's exact test, t-test and chow's test for comparing differences between Korean and Chinese. We estimated the odds ratio for perceived symptoms during ADE by preventive behavior, using Generalized Estimation Equation (GEE). The study indicated that there were significant differences between symptoms in Korea and those in China such as cold, cough, and sore throat, especially in elderly. Preventive behaviors such as avoiding outdoor activity and wearing sunglasses were more often performed in China than Korea. However wearing mask was more often performed in Korea than China. After adjusting for age, sex, educational level, and smoking status, the odds ratio (OR) of dry cough symptom in Korea was significantly decreased by closing the windows and wearing a mask during ADE. In China, the OR of dry cough symptom was decreased by wearing a mask and avoiding outdoor activity. We found that China which had higher performance of preventive behavior showed lower prevalence of symptoms during ADE than Korea. Also preventive behaviors could affects prevalence of symptoms during ADE. This results suggest that preventive behavior. could reduce symptoms during ADE and there are needed for. more attentions to reduce a threat of ADE.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.479-483
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• 2006

[ ${\beta}-Glucan$ ], one of the cell wall components, is most plentiful polysaccharides in cell wall and has several advantages in immune system. In yeast ${\beta}-glucan$ is mainly contained in the yeast cell wall, and thus it is important to produce high levels of cell mass for the mass production of yeast ${\beta}-glucan$. The best carbon and nitrogen sources on cell mass production were high fructose syrup and yeast extract. Response surface methodology (RSM) was very potential tool for the optimization of process factor and medium component. It was applied to estimate the effects of medium components on the production of cell mass. Optimal concentrations of high fructose syrup and yeast extract by response surface methodology were 8.0% (v/v) and 5.2% (w/v), respectively and the cell mass predicted was $17.0\;g/{\ell}$ at 20 h of cultivation.