• Journal of Periodontal and Implant Science
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• v.39 no.sup2
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• pp.269-278
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• 2009

Purpose: The aim of this study was to investigate matrix metalloproteinase 1 (MMP-1) gene polymorphism (1G/2G at -1607 and A/G at -519) in Korean subject and to assess the association between polymorphism and periodontal status. Methods: Forty nine generalized aggressive periodontitis (GAP) patients and 57 periodontally healthy children were recruited and genomic DNA was extracted from buccal swab. The polymorphisms of MMP-1 promoter genes were determined by polymerase chain reaction and restriction fragment length product (PCR-RFLP) method. The distribution of genotype and allele frequency was compared between 2 groups by ${\chi}^2$ test. Results: There was a significant difference in the distribution of genotypes and frequency of alleles between the GAP and reference groups at the position - 519 of MMP-1 gene promoter (P<0.05). Allele G carrier rate was significantly lower in GAP group than that of the reference group (P< 0.001). At the position -1607 of MMP-1 gene promoter, genotype distribution and allele frequency showed no statistically significant difference between the groups. However, in the female group, a significant difference was observed between the groups for the genotype distribution, allele frequency and allele 1G carrier rate (P< 0.05). Conclusions: The DNA polymorphism at the MMP-1 gene promoter might be associated with GAP in Korean.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.687-697
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• 1999

A finite element analysis has been utilized to analyze stress and strain fields and design a new configuration in orthopedics and implant dentistry. Load transfer and stress analysis at implant bone interface are important factors from treatment planning to long term success. Bone configuration and quality are different according te anatomy of expecting implantation site. The purpose of this study was to compare the stress distribution in maxilla and mandible accord-ing to implant length and bone engagement types. A three dimensional axi-symmetric implant model(Nobel Biocare, Gothenburg, Sweden) with surrounding cortical and cancellous bone were designed to analyze the effects of bone engagement and implant length on stress distribution. ANSYS 5.5 finite element program was utilized as an interpreting toot. Three cases of unicortical anchorage model with 7, 10, 13 mm length and four cases of bicortical anchorage model with 5, 7, 10 and 13 mm length were compared both maxillary and mandibular single implant situation. Within the limits of study, following conclusions were drawn. 1. There is a difference in stress distribution according to cortical and cancellous bone thickness and shape. 2. Maximum stress was shown at the top of cortical bone area regardless of bone engagement types. 3. Bicortical engagement showed less stress accumulation when compared to unicortical case overall. 4. Longer the implant future length, less the stress on cortical bone area, however there is no difference in mandibular bicortical engagement case.

• The Journal of Advanced Prosthodontics
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• v.10 no.2
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• pp.138-146
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• 2018

PURPOSE. The purpose of this study was to analyze the effects of the splinted implant prosthesis in a reconstructed mandible using three-dimensional finite element analysis. MATERIALS AND METHODS. Three-dimensional finite element models were generated from a patient's computed tomography data. The patient had undergone partial resection of the mandible that covered the area from the left canine to the right condyle. The mandible was reconstructed using a fibula bone graft and dental implants. The left mandibular premolars and molars remained intact. Three types of models were created. The implant-supported prosthesis was splinted and segmented into two or three pieces. Each of these models was further subcategorized into two situations to compare the stress distribution around normal teeth and implants. Oblique loading of 300 N was applied on both sides of the mandible unilaterally. The maximum von Mises stress and displacement of the models were analyzed. RESULTS. The stress distribution of the natural mandible was more uniform than that of the reconstructed fibula. When the loading was applied to the implant prosthesis of reconstructed fibula, stress was concentrated at the cortical bone around the neck of the implants. The three-piece prosthesis model showed less uniform stress distribution compared to the others. Displacement of the components was positively correlated with the distance from areas of muscle attachment. The three-piece prosthesis model showed the greatest displacement. CONCLUSION. The splinted implant prosthesis showed a more favorable stress distribution and less displacement than the separated models in the reconstructed mandible.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.81-95
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• 1994

This study was performed in a diatomite factory where silicosis had been found at October, 1993. The major objectives were to evaluate worker exposure to diatomaceous earth and to present engineering control methods for workplace management. Total and respirable dust of diatomaceous earth were measured. Size distribution of dust was analyzed by applying the multiple diffraction method. Also crystalline silica in respirable dust samples was analyzed qualitatively by X-ray diffraction. The suitable Local Exhaust Ventilation systems for that factory were recommended. The results were as follows. The airborne total and respirable dust concentrations by exposure groups showed approximate normal distribution. The means of total dust exposures at flour maufacturing, fire brick grinding and packaging, ceramic raws packaging processes exceeded Korean and ACGIH standards, $10mg/m^3$. The means of total and respirable dust concentrations to high exposure groups were 6.8 and 3.9 times higher than those of low expousre groups, respectively. The size distribution of diatomaceous earth dust was lognormal with a median diameter of $7.07{\mu}m$(range, $0.10-60.0{\mu}m$) and with a geometric standard deviation of 1.43. The crystalline silica in respirable dust samples was identified to quartz and cristobalite and/or tridymite. Above results suggest that engineering controls and periodic environmental and medical surveillances will be important for preventing silicosis in the diatomite factory.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.428-436
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• 2010

Sea-urchins (Anthocidaris crassispina) are widely distributed in the East Sea of Korea. The aim of this study was to evaluate the hepatoprotective effects of sea-urchin roe on bromobenzene (BB)-induced liver damage in rats. The antioxidative and detoxifying properties of sea-urchin roe in BB-poisoned rat liver was examined by chemical analysis of serum aminotransferase (AST, ALT), glutathione S-transferase (GST), $\gamma$-glutamylcystein synthetase, glutathione reductase, epoxide hydrolase, amino-N-demethylase (AD), aniline hydrolase (AH) enzyme activity, as well as lipid peroxide and glutathione contents. Sea-urchin roe inhibited the increase of serum AST, ALT enzyme activity. Increasing lipid peroxide contents and AD and AH activities were significantly decreased in ethanol extract of sea-urchin roe. GST, $\gamma$-glutamylcystein synthetase, glutathione reductase and epoxide hydrolase enzyme activities increased in sea-urchin roe-fed group, compared with the BB-treated group. These results suggest that sea-urchin roe facilitates recovery from liver damage by enhancing antioxidative defense mechanisms and hepatic detoxication metabolism.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.319-331
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• 2015

The marketing system of non-timber forest products has been criticized as it mainly depends upon private local dealers, having too many steps between producers and consumers, we believe, which makes it less efficient. Meanwhile, there were only a few empirical studies of how they are delivered to consumers. In order to devise and implement targeted forest policies efficiently, it is quite necessary to understand the distribution channel of them. We analyzed the distribution channel of chestnut, bitter persimmon, oak mushroom, and wild greens by data analysis, field and phone survey, and then drew an implication for improving the marketing system. First of all, the number of middle step has to be reduced and the direct transaction has to be expended. In addition, we need to have more active involvement of Forest cooperative in production sites, adding values by processing, and the upgrade of current marketing centers of non-timber forest products, which have been launched since 2004 by Korea Forest Service.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.70-78
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• 2013

Plants which are having conditions of high temperature and pressure always are exposed to danger. In order to prevent unexpected accidents, safety management that can effectively and appropriately examine facilities is required in plant operation. RBI(Risk-Based Inspection) technology in API 581 is one of standard management technique for evaluating risk on petroleum plants. There are qualitative and quantitative assessments in RBI methodology. Quantitative evaluation step is complex and required much information, so high-risk facilities in plant are selected firstly by qualitative method. Qualitative RBI is performed by choosing the answer in prepared questionnaire. However, it is difficult to believe thoroughly results from survey including ambiguous information. In this study, the procedure of qualitative RBI analysis with considering probability distribution concept were proposed by using Monte Carlo simulation method in order to increase reliability in spite of uncertain factors. In addition, qualitative risk of cooling system for LNG plant was evaluated using proposed procedure. Although 20 items of total 39 assessment items are applied to uncertain factors, risk section of high probability(89%) were verified. The detailed results were described in manuscript.

• The Korean Journal of Ceramics
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• v.6 no.4
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• pp.380-384
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• 2000

Crystal structure of $Ba_5-5X$Y$_10/3$Nb$_10$O$_30$ was tried to determine by Rietveld analysis using powder X-ray diffraction data. This compound has tetragonal tungsten bronze (TTB) structure with general formula, (Al)$_2$(A2)$_4$(B1)$_2$(B2)$_8$(O1)$_8$(O2)$_8$(O3)$_4$(O4)$_2$(O5)$_4$(O6)$_4$. However, it was difficult to determine the distribution of Ba and Y in Al and A2 sites by the analysis only. Combination of Rietveld analysis and site potentials calculation as well as lattice energy calculations helped to determine the distribution. As the result, it was clarified that $Ba^2+$ cations occupy A2 (pentagonal tunnel site) and $Y^3+$ cations occupy Al (cubic site). The distribution of cations at each site coincides with the distribution estimated by the difference of ionic radii. This supports the formation condition of TTB which was proposed in our previous report. $Ba_5-5X$Y$_10X/3$Nb$_10$O$_30$ shows ferroelectric characteristics. In this compound, remanent polarization decreases slightly with the composition X. On the other hand, the result of crystal structure determination reveals that atomic positions along c-axis for A1, A2, B1 and B2 cations are also decreased with the composition X. This would suggest that the dependence of remanent polarization on composition X is derived by the dependence of atomic coordinates on composition X.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.51-62
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• 2006

Purpose: The purpose of this study was to evaluate the pattern and the magnitude of stress distribution in the supporting tissues surrounding three different types of implants(ITI, 3i. and Bicon implant system) Material and method: Photoelastic models were made with PL-2 resin(Measurements Group, Raleigh, USA) and three implants of each kind were placed in the mandibular posterior edentulous area distal to the canine. For non-splinted restorations, individual crowns were fabricated on three titanium abutments. For splinted restorations, 3-unit axed partial dentures were fabricated. Photoelastic stress analyses were carried out to measure the fringe order around the implant supporting structure under simulated loaded conditions(15 lb. 30 lb). Conclusion: The results were as follows; 1 Regardless of the implant design, stresses were increased in the apex region of loaded implant when non-splinted restorations were loaded. While relatively even stress distribution occurred with splinted restorations. Splinting was effective in the second implant. 2. Strain around Bicon implant were lower than those of other implants, which confirmed the splinting effect. The higher the load, the more the stress occurred in supporting tissue, which was most obvious in the Bicon system. 3. Stress distribution in the supporting tissue was favorable in the ITI system. while the other side of 3i system tended to concentrate the stress in some parts.

• Nutritional Sciences
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• v.5 no.1
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• pp.13-19
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• 2002

A mutation in the promoter region of uncoupling protein 3 (UCF3), specifically the -55C longrightarrow T transition, may influence an individual's energy metabolism and body weight. The objective of this study was to investigate the effect of a weight reduction program on endocrine functions and body fat distribution, related to UCP3 promoter genotype. Ninety overweight pre-menopausal female subjects participated in the weight reduction program at Yonsei University Hospital, and were placed on a calorie-restricted diet (300 kcal less than their daily requirements) for 12 weeks. After 12 weeks, all subjects on the program lost approximately 5% of their initial body weights and had lower Body Mass Index (BMI) values. Among the 90 women, 56 had a normal (without mutation) UCP3 genotype, while 34 women had mutations in the promoter region of UCP3. Despite similar weight reductions in both groups, a significantly higher decrease in abdominal adipose tissue was observed in the normal UCP3 genotype group, compared to the group with mutations. In particular, there was a significant reduction of fat at the lumbar 1 (Ll) level in the without-mutation group. Serum levels of total cholesterol, apolipoprotein Al were significantly decreased in the without-mutation group, by 4.4% and 5.7% respectively. Serum levels of hormones were not significantly changed in both groups artier the intervention. However, in the group without the mutations, the leptin level significantly reduced by 23.4% (p<0.001). Serum free fatty acid (FFA) concentration was significantly increased in the group with mutation following the weight reduction program. On the other hand, FFA responses were shown similar increases in both groups. In conclusion, although no difference was found in the magnitude of weight reduction in both groups, there were significant differences in body fat distribution and in endocrine function between the groups.