• Journal of Periodontal and Implant Science
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• 제38권3호
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• pp.551-556
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• 2008

Purpose: Cemental tear is an uncommon form of root fracture that can lead to rapid localized attachment loss. When it is exposed in the periodontal pocket, it should be removed to prevent accumulation of dental plaque and calculus. Material and Methods: 2 patients were diagnosed as a cemental tear and they were treated with conventional flap operation and subgingival curettage. Additional treatments such as bone graft or guided tissue regeneration were not performed. Result: Symptoms subsided after the treatment. Periodontal pocket has been reduced but no gain of clinical attachment was observed. Remnant of cemental fragment remained after curettage. However, periodontal pocket was stably maintained and there was no recurrence. Conclusion: Periodontal attachment loss associated with cemental tear can be successfully treated with conventional periodontal surgical and nonsurgical procedures.

• Tribology and Lubricants
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• 제25권1호
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• pp.43-48
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• 2009

It is reported by many researchers that the textured bearing surfaces, where many tiny micro-pockets or enclosed recesses were incorporated, can enhance the load support and reduce friction force. Recently, the basic lubrication mechanism of micro-pocketed parallel surfaces are explained in terms of "inlet suction" using continuity equation and simply cavitation condition. However, it is required that more actual cavitation condition in the pocket region should be applied to estimate exact bearing performance. In this paper, a commercial computational fluid dynamics (CFD) code, FLUENT is used to investigate the exact lubrication characteristics of infinitely long slider bearing with micro-pockets. The results show that the pressure distributions are highly affected by pocket depths, its positions and numbers. The numerical method adopted in this paper and results can be use in optimal design of textured sliding bearings.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1346-1350
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• 2018

An electrode-evaporation technology on both the top and bottom sides of the bare vertical-type single chip separated from the traditional substrate by cooling, was developed for III-nitride vertical-type single chip LEDs with thick GaN epilayer. The post-process of the cooling step was followed by sorting the bare vertical-type single chip LEDs into the holes in a pocket-type shadow mask for deposition of the electrodes at the top and bottom sides of bare vertical-type single chip LEDs without the traditional substrate for electrode evaporation technology for vertical-type single chip LEDs. The variation in size of the hole between the designed shadow mask and the deposited electrodes owing to the use of the designed pocket-type shadow mask is investigated. Furthermore, the electrical and the optical properties of bare vertical-type single chip LEDs deposited with two different shapes of n-type electrodes using the pocket-type shadow mask are investigated to explore the possibility of the e-beam evaporation method.

• 지역사회간호학회지
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• 제16권2호
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• pp.196-204
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• 2005

Purpose: This study was to investigate the relation among social support, drinking and smoking and to identify factors affecting high school students' smoking and drinking behaviors. Methods: Data were collected from 361 high school students (182 students in 2 preparatory schools and 179 students in 2 vocational high schools) who were selected through convenient sampling. Data were analyzed using SPSS 11.5 for Windows. Results: Factors affecting smoking behavior were drinking(OR=15.86. p<0.01), school type(R=11.82, p<0.01), school record(OR=46.62. p<0.001), pocket money (OR= 10.91. p<0.01) and brother's smoking (OR=9.09. p<0.05). Factors affecting drinking behavior were smoking(OR=8.32. p<0.01), school type(OR=2.53. p<0.01), school record(OR=2.35. p<0.01), pocket money(OR=2.01. p<0.05), father's educational background(OR=2.126. p<0.05), mother's drinking(OR= 1.83. p<0.05) and relationship with teacher (OR=2.44. p<0.01). Conclusion: The behaviors of drinking and smoking in high school students were highly correlated with each other. School record, school type, pocket money and family member's behaviors influenced student's behaviors. Further study is required to estimate the effect of drinking and smoking intervention programs according to student's characteristics such as school record, school type, pocket money management, and family members' influence.

• 한국치위생학회지
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• 제16권2호
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• pp.225-231
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• 2016

Objectives: The purpose of this study was to investigate the influential factors of stress and fatigue on peridontal indicators in patients with periodontal disease. Methods: A self-administrated questionnaire study was conducted during November 2012 to January 2013 with 140 periodontal patients. The Fatigue and Stress were evaluated with Multidimensional Fatigue Scale(MFS) and Psychosocial Well-bing Index(PWI). Periodontal health indicators were consisted with gingival index and pocket depth. Data were analyzed by descriptive analysis, t-test, ANOVA, and multiple regression analysis. Results: Overall stress and fatigue level of subjects were $22.61{\pm}5.62$ and $64.67{\pm}9.45$. Gingival index and periodontal pocket depth as periodontal health indicators were $1.26{\pm}0.3$ and $4.29{\pm}0.52$. The influential factors of gingival index and periodontal pocket depth were social function(subcategory of pwi) and depression(subcategory of pwi), respectively. Conclusions: Some subcategories of PWI were related with periodontal health indicators. So, consideration of stress related with depression and social function are needed to manage and prevent periodontal disease.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.631-642
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• 2002

The present study evaluated of regeneration effect of platelet rich plasma on the treatment of classII furcation involvement, with allograft in humans. The control was treated without bioabsorbable membrane, and the test was treated with bioabsorbable membrane. Pocket depth, clinical attachment level, and gingival recession were measured at baseline, postoperative 3, 6months. Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. The change of pocket depth and clinical attachment level in both groups was decreased significantly at 3, 6months.(p<0.05) 2. The change of gingival recession in both groups was increased significantly at 3, 6months than at baseline.(p (0.05) 3. The change of pocket depth and clinical attachment level in both groups was increased significantly at 3, 6months, but there were no statistically or clinically significant differences with both groups. 4. The change of gingival recession in both groups was increased significantly at 3, 6months, but there were no statistically or clinically significant differences with both groups. 5. The significant reduction of the pocket depth and clinical attachment level exhibited marked changes at 3 months in both groups. In conclusion, the results of this study suggest that there are no statistically or clinically significant differences between with and without bioabsorbable membrane on treatment of classII furcations using allograft and PRP

• International Journal of Oral Biology
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• 제40권2호
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• pp.93-101
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• 2015

The efficacy of air-polishing on subgingival debridement, as compared to scaling and root planning (SRP), was evaluated clinically and microbiologically. Fifteen patients diagnosed as chronic periodontitis, and having single-root tooth over 5 mm of pocket depth symmetrically in the left and right quadrant, were investigated. Subgingival debridement was performed by SRP and air-polishing. The results were evaluated and compared clinically and microbiologically. Probing pocket depth (PPD), bleeding on probing (BOP), relative attachment level (RAL) and change of gingival crevicular fluid (GCF) were assessed before treatment, and at 14 and 60 days after treatment. Microbial analysis was done pre-treatment, post-treatment, and at 14 and 60 days after treatment. Results of air polishing showed that post treatment, the PPD and BOP decreased, and attachment gain was observed. There was no clinical difference when compared to SRP. The volume of GCF decreased at 14 days, and increased again at 60 days. Compared to SRP, there was a statistical significance of the volume of GCF at 60 days in air-polishing. In the microbial analysis, high-risk bacteria that cause periodontal disease were remarkably reduced. They decreased immediately after treatment, but increased again with the passage of time. Thus, our results show that subgingival debridement by air-polishing was effective for decrease of pocket depth, attachment gain, decrease of GCF and inhibition of pathogens. Further studies are required to compare air-polishing and SRP, considering factors such as degree of pocket depth and calculus existence.

• Tribology and Lubricants
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• 제31권6호
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• pp.281-286
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• 2015

Automotive transmission systems are assembled with a large number of gears and shafts, and rolling bearings are used to ensure their smooth operation. Gear oil in the gear box contains solid particles such as wear debris from contacting gears and metallic chips. This particle-enriched lubricating oil can cause premature failure of the rolling bearings. Research aimed at improving the service life of these rolling bearings has been confined mainly to design and lubrication of the inner/outer rings and the rolling elements. In this paper, we redesigned the shape of the cage pocket of a deep groove ball bearing to reduce the premature failure due to particle contamination. Test bearings are assembled with this new cage design containing a hole punched in the cage pocket. Endurance tests are carried out using the contaminated lubricating oil with miracle grid as hard particle. The duration and damaged bearing component shapes are compared for two different cages. The B₁₀ life of bearing with new cage is increased by about 66% compared to the conventional cage. This is because the hard particles can be easily discharged through the pocket hole without staying for a long time in the lubrication regions. This greatly decreases abrasive wear and dents on the highly stressed ball bearing surfaces. Therefore, the cage design of this study, containing a pocket hole, can significantly delay the premature failure of rolling bearings and improve the endurance life.

• 한국조경학회지
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• 제32권1호
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• pp.23-32
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• 2004

This study aims to examine constraints on visits to urban community parks and to find ways to elevate the efficient use of parks. To achieve this, the study relied on empirical study method and the descriptive method; additionally, present condition survey was performed with a user interview, on the assumption that a park visit is a form of leisure. As a result, the item of 'insufficient lighting facilities' shows the highest mean and the item of 'low quality of park' follows Previous research also revealed that the item of 'the lack of lighting facilities' is a major factor on user dissatisfaction, so a design and management program for night time users are fully researched and elaborately accomplished. Also, the high response of 'low quality of park' shows that the park supply policy in Korea focusses mainly on quantity so far, and it shows that user's dissatisfaction for park facilities becomes one of the major constraints of park visit. The factor analysis, on the object of 35 items except 2 items, appeared 5 factors: accessibility, inner discord, companion, family matters, park-itself-matters. Oneway Anova test showed that 4 factors except 'park-itself-matters' have reliable difference in constraint cognition by age and education. The visit constraint of 'park-itself-matters' did not appear different by any personal characteristics. Without regard to personal characteristics, it is regarded that this factor has the greatest effect upon park visits. In general, people who are disadvantaged strongly cognize constraints even in leisure such as a park visit, which is a simple and inexpensive leisure activity. Therefore, a park like a pocket park, which is small but located in a neighborhood, is more needed than a central park like a symbolic and huge park in every new city. Careful concern for night activity should be accomplished in the planning process.

• Genomics & Informatics
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• 제6권3호
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• pp.142-146
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• 2008

In order to understand the protein functions that are related to disease, it is important to detect the correlation between amino acid mutations and disease. Many mutation studies about disease-related proteins have been carried out through molecular biology techniques, such as vector design, protein engineering, and protein crystallization. However, experimental protein mutation studies are time-consuming, be it in vivo or in vitro. We therefore performed a bioinformatic analysis of known disease-related mutations and their protein structure changes in order to analyze the correlation between mutation and disease. For this study, we selected 111 diseases that were related to 175 proteins from the PDB database and 710 mutations that were found in the protein structures. The mutations were acquired from the Human Gene Mutation Database (HGMD). We selected point mutations, excluding only insertions or deletions, for detecting structural changes. To detect a structural change by mutation, we analyzed not only the structural properties (distance of pocket and mutation, pocket size, surface size, and stability), but also the physico-chemical properties (weight, instability, isoelectric point (IEP), and GRAVY score) for the 710 mutations. We detected that the distance between the pocket and disease-related mutation lay within $20\;{\AA}$ (98.5%, 700 proteins). We found that there was no significant correlation between structural stability and disease-causing mutations or between hydrophobicity changes and critical mutations. For large-scale mutational analysis of disease-causing mutations, our bioinformatics approach, using 710 structural mutations, called "Structural Mutatomics," can help researchers to detect disease-specific mutations and to understand the biological functions of disease-related proteins.