• Toxicological Research
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• v.21 no.2
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• pp.151-160
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• 2005

In order to monitor the histological and general profiles of lung after direct expose of p,p-DDE, 1, 5 and 10 mg/ml of p,p-DDE were sprayed to male ICR mouse, and seven days after exposure, changes of body weight, lung weight, clinical signs, histological profiles of lung and total WBC in blood were investigated with changes of total cell number and their differential count in bronchoalveolar lavage fluid (BALF). In the present study, a significant and dosage-dependent decrease of body weight was detected in p,p-DDE exposed groups and body weight gains during observational periods (7 days) were also significantly and dosage-dependently decreased in p,p-DDE exposed groups compared to that of vehicle control group. In addition general depression signs were detected in all p,p-DDE exposed groups with dosage-dependent manners, and lung weights were also increased in p,p-DDE exposed groups. Congestion, hemorrhage and severe exudate were observed in the lung of p,p-DDE exposed groups with sarcomatous changes and these signs were also showed by dosage-dependent manners. In addition, foreign body pneumonia signs were observed in the lung of p,p-DDE exposed groups in histological levels. The percentage of ALSA (Area of luminal surface of alveoli) was also significantly and dosage-dependently decreased in p,p-DDE exposed groups and total blood WBC and BALF cell numbers were significantly and dosage-dependently increased in p,p­DDE exposed groups compared to that of vehicle control group and increase percentage of neutrophil, eosinophil, and lymphocyte in BALF were monitored in p,p-DDE exposed groups compared to that of vehicle control group. In conclusion, severe allergic response and/or foreign body pneumonitic changes were induced by direct exposure of p,p-DDE containing beverage. So it is considered that strong and powerful regulation was need to control production of residence of environmental pollutant especially to p,p-DDE.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.335-341
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• 2012

This study conducted a survey targeting at dental hygienists working in medical institutions located in Daegu, Pusan, Ulsan Metropolitan City and Gyeongnam and Gyeongbuk Province from July 18th to August 26th 2011, in order to study factors which affect radiation safety management behaviors and improve levels of those behaviors. The results of this study are as follows. 1. There were significant differences in radiation safety management knowledge of dental hygienists, according to service institutions (p<.001), the current state of defense facilities (p<.006) and the necessity for safety management education (p<.012). 2. There were significant differences in radiation safety management attitudes, according to age (p<.014), service institutions (p<.003), work experience (p<.009), educational level (p<.002), the current state of defense facilities (p<.015), the necessity for safety management education (p<.005) and the intention to take part in the education (p<.036). 3. There were significant differences in radiation safety management behaviors, depending on experience in safety management education (p<.068), measurement of exposed dose (p<.010), the state of defense facilities (p<.001). 4. There were statistically positive correlations between radiation safety management knowledge and attitude, and between radiation safety management attitude and behavior (p<.05). 5. The regular measurement of exposed dose (p<.046) and the present state of defense facilities (p<.001) were found to be factors to affect radiation safety management behaviors. In conclusion, it is considered that building perfect defense facilities of radiology rooms and measuring the exposed does of dental hygienists on a regular basis to alert them to the danger of radiation is considerably important to improve radiation safety management behaviors.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.257-274
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• 2001

To properly prepare teeth, dentists require a direct view of the working area and are often placed in a difficult position, moreover, a high proportion of dentists suffer from headache and back pain. Dentists who make use of the dental mirror and position their patients carefully to gain a proper view report less headache, pain and discomfort in the shoulders. It is recommended that dentists learn the "Home Position(H.P.)" which among the various "Random Position(R.P.)" methods, enables dentists to approach their patients in a stable posture. The purpose of this study was to compare tooth preparation in the H.P. and the R.P., and evaluate the clinical efficacy of the H.P.. Tooth preparation for a full cast crown was performed on the maxillary left 1st molar using the H.P. and the R.P., and the shapes of the prepared tooth surfaces at the two different operating positions were compared. The amount of occlusal reduction, marginal width, height, and axial taper were measured and analyzed. A T-test was performed separately to compare the results of the H.P. and the R.P. with respect to the accuracy of the corresponding tooth reduction. The results were as follows. ; 1. The amount of occlusal reduction was excessive on the mesiobuccal cusp(P<0.05), and deficient on the lingual cusp in the H.P.(P<0.01). In the R.P., this was excessive on the buccal cusp and deficient on the fossa and distolingual cusp(P<0.01). 2. The amounts of marginal width were excessive in all areas except on the lingual and mesial surfaces in the H.P. and lingual surface in the R.P.(P<0.01). 3. The marginal heights were achieved more accurately in the R.P. than the H.P.(P<0.01). 4. Axial surface taper was excessive in all areas in the H.P.(P<0.01). But the axial taper of measured areas was even, and tooth is more like to retain its original axis after reduction. In the R.P., axial surface taper was excessive on the mesial and buccal area, and deficient on the distolingual area(P<0.01), and therefore, the axis of the prepared teeth was tipped in the distolingual direction. 5. The times needed for preparation were 12 minutes and 49 seconds in the H.P., and 11 minutes and 35 seconds in the R.P., and the R.P. was statistically faster(P<0.01). The tooth preparation in the H.P. achieved its goal, in that it enabled the operator to make even tooth reduction. In conclusion, the H.P. system offers an improved method that can be used in clinic after specific training.

• Journal of KIISE:Information Networking
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• v.31 no.1
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• pp.11-19
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• 2004

P2P network environments provide users with direct data transmission and sharing facilities and those environments can be classified into hybrid P2P network environments and pure P2P network environments according to the arbitration mechanism among the peers in the network. In hybrid P2P network environments, there exists a server that maintains index information for the data to be shared and network isolation does not occur because every peer always keeps connection to the server. In pure P2P network environments, however, each peer directly connects to another peer and gets services without server intervention, and so, network isolation can occur when the mediating peer fails to work. In this paper. we propose a scheme for each peer to keep connection to other peers continuously by maintaining IP addresses of its neighbor peers and connecting to the peers when the mediating peer fails to work. Although the P2P application that uses our proposed framework should obtain one or more IP addresses of the neighbor peers manually, after instantiation, the application can do its job while maintaining connection to the network continuously and automatically. To evaluate our proposed scheme, we measured and analyzed the time for a peer to reconnect to the network when the mediating peer fails and the network isolation occurs.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.17-22
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• 2013

In this study, a pH control method by carbon dioxide ($CO_2$) was applied to coagulation process in water treatment plant (WTP) to investigate the coagulation efficiency and residual dissolved aluminum when high pH raw water is flowing into the plant during algal blooming. Existing coagulant dose (1 mg/L in raw water) resulted in the pH reduction of 0.0384 by LAS, 0.0254 by PAC, 0.0201 by A-PAC, and 0.0135 by PACS2, respectively. And then the concentration of dissolved aluminum was 0.02 mg/L at pH 7.44, 0.07 mg/L at pH 7.96, 0.12 mg/L at pH 8.16, 0.39 mg/L at pH 8.38 showing the concentration increase with pH in the coagulation process. It was noteworthy that rapid increase was observed at pH above 8.0 next the rapid mixing. Therefore it is necessarily required to control pH below 7.8 in the coagulation process in order to meet drinking water quality standard of aluminum for high pH raw water into WTP, $CO_2$ injection could control pH successfully at about 7.3 even for the raw water of high pH above 8.0. In addition it was found that the pH control by $CO_2$ injection was significantly effective for coagulation in terms of turbidity removal, coagulant dosage, and residual dissolved aluminum concentration.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.2
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• pp.169-177
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• 2003

Purpose: The purpose of the current study is to evaluate the correlation between the expressions of p21 and p27 in osteosarcoma, and prognostic impact such as local recurrence, distant metastasis and survival rate. Materials and methods: Between 1988 and 2001, forty patients who underwent surgery, followed more than 12 months, and whose pathologic blocks were available, were evaluated retrospectively. Their formalin-fixed and paraffin-embedded tumor specimens were investigated. The correlation between expressions of p21, p27, local recurrence, distant metastasis and survival rate was statistically evaluated. Results: p21 protein was expressed in 38 (95%) patients. p27 protein was expressed in 14 (35%) patients. Patients with high expression of p21 had more frequent metastasis and poorer results (p=0.024). In contrast with these findings, patients with positive staining of the p27 had the significant lower distant metastasis (p=0.028). Conclusion: The prognosis of the osteosarcoma according to the expression level of p21 and p27 had inverse relationship which had unknown mechanism. Further work will be needed to define the relationship between p21 and p27.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.26-32
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• 1995

This study was carried out to investigate the effect of protease on the functionality of soymilk protein. The protease from Bacillus polymyxa was selected because of the least production of bitter taste and calcium-aggregation. The results are summarized as follows: 1. Solubility of SMP(soymilk protein) and SPI(soyprotein isolate) were lowest at pH 4.7 and increased as the pH value reached closer to either ends. PT-SMP(pretense treated soymilk protein) showed higher solubility at all pH range, especially at pH 4.7 than SMP, SPI. 2. Emulsion activity of three samples was lowest at pH 4.7 and significantly increased as pH approched higher acidic or alkaline regions. PT-SMP showed similar activity to other samples, but less stability. 3. Foam capacity of PT-SMP was lowest at pH 8 and increased in acidic, alkaline pH. PT-SMP showed higher foam capacity at all pH range, but lower foam stability than SMP and SPI. 4. PT-SMP showed higher heat coagulability than other samples at all pH range except pH 4.7.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.343-349
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• 1990

The solubility of protein and phytate was measured at various pH's in distilled water and at various concentrations of NaCl, $CaCl_2\;and\;Na_2SO_3$ solutions, and then optimum condition for producing low phytate protein isolate from perilla flour was investigated. The protein solubility in water showed minimum at pH 4.0 and increased at pH higher or lower than 4.0, while phytate solubility was highest at pH 5.0 and decreased at pH higher or lower than 5.0. In NaCl solution, protein solubility was lowest between pH 3.0-4.0, while phytate solubility was high between pH 2.0-5.0 and abruptly decreased above PH 6.0. In $Na_2SO_3$ solution, protein solubility was lowest between pH 2.0-3.0 and phytate solubility showed maximum values between pH $5.0{\sim}6.0$, and it's solubility was low in 3% salt concentration at all pH ranges. In $CaCl_2$ solution, protein solubility in 3% salt concentration was relatively low at all pH ranges, and phytate solubility showed highest values between pH $2.0{\sim}3.0$ and abruptly decreased (1.0%) above pH 4.0. In order to make low phytate protein isolate, defatted perilla flour protein was extracted at pH9.0 and precipitated at pH 4.0 in 3% NaCl solution. The yield of low phytate protein isolate was 61.4% of total protein. This protein was found to contain 0.02% phytate by weight.

• Solar Energy
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• v.11 no.3
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• pp.74-83
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• 1991

In this study, the (p)ZnTe/(n)Si solar cell and (n)CdS-(p)ZnTe/(n)Si poly-junction thin film are fabricated by vaccum deposition method at the substrate temperature of $200{\pm}1^{\circ}C$ and then their electrical properties are investigated and compared each other. The test results from the (p)ZnTe/(n)Si solar cell the (n)CdS-(p)ZnTe/(n)Si poly-junction thin fiim under the irradiation of solar energy $100[mW/cm^2]$ are as follows; Short circuit current$[mA/cm^2]$ (p)ZnTe/(n)Si:28 (n)CdS-(p)ZnTe/(n)Si:6.5 Open circuit voltage[mV] (p)ZnTe/(n)Si:450 (n)CdS-(p)ZnTe/(n)Si:250 Fill factor (p)ZnTe/(n)Si:0.65 (n)CdS-(p)ZnTe/(n)Si:0.27 Efficiency[%] (p)ZnTe/(n)Si:8.19 (n)CdS-(p)ZnTe/(n)Si:2.3 The thin film characteristics can be improved by annealing. But the (p)ZnTe/(n)Si solar cell are deteriorated at temperatures above $470^{\circ}C$ for annealing time longer than 15[min] and the (n)CdS-(p)ZnTe/(n)Si thin film are deteriorated at temperature about $580^{\circ}C$ for longer than 15[min]. It is found that the sheet resistance decreases with the increase of annealing temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7656-7666
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• 2015

The purpose of this study was to explore the determinants of subjective happiness among Korean adolescents and to supply basic data for enhancing to subjective happiness among Korean adolescents. This study used the 2014 Korean Youth Health Risk Behavior On-lin Survey data. It conducted a secondary data analysis of 72,060 cases. It conducted frequency analysis, t-test, ANOVA and multiple regression analysis by SPSS 18.0. Although various independent variables influenced on emotional support(t=44.335, p<,001), gender(t=27.730, p<.001), grade(t=25.347, p<.001), economic status(t=-25.345, p<.001), living arrangement(t=-6.158, p<.001), school record(t=-7.512, p<.001), father's educational status(t=-2.378, p<.001), subjective health status(t=46.062, p<.001), depression(t=-23.837, p<.001), sleep(t=19.871, p<.001), level of stress(t=-78.685, p<.001), alcohol(t=-13.481, p<.001) and drug use(t=-2.671, p<.01), smoking(t=-11.988, p<.001), breakfast(t=4.443, p<.001), activity(t=4.757, p<.001) were key factors of subjective happiness among Korean adolescents. The findings of this study were as follow: male middle students, who had emotional support, higher economic status, school record and father's educational level, living with family showed higher levels of subjective happiness. It also having good subjective health status, not depressed, more sufficient sleep, lower stress, no experience of drinking, smoking and drugs, more physical activity and having breakfast showed higher levels of subjective happiness.