• 환경영향평가
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• 제16권4호
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• pp.241-250
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• 2007

A study was carried out on the level of heavy metals, total coliform and benzo(a)pyrene that may be introduced through by-product fertilizers or air pollution to turfgrass in natural turfgrass playground in elementary schools around the western coast and eastern mountain areas in Jeollabuk-do, Korea. The level of heavy metals found in turfgrass was in the order of Cu > Zn > Pb > Cd. The majority of heavy metals was found in the roots. It is presumed that the absorption of some air pollutants and by-product fertilizers or chemical fertilizers. The level of benzo(a)pyrene showed an average of 0.05ng/g with a range between 0.02 to 0.08ng/g in the leaves. In the meantime, none was detected in the stems, while the average for roots was 0.02ng/g with a range between 0.01 and 0.03ng/g. The level detected is that found background level, however, benzo(a)pyrene can be introduced partly from the unstable combustion of fossil fuel or through vehicle emissions. Total coliform distributed in grass showed an average of 12MPN/100ml with a range between 2 and 36MPN/100ml. The density of total coliform displayed no regional predominance. However, in some urban areas, the density was slightly higher. The feces of pets or by-product fertilizers may have contributed to the input of pathogenic micro-organism. Yet the level was found to be negligible.

• Journal of Korean Neurosurgical Society
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• 제61권5호
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• pp.559-567
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• 2018

Objective : The aim of this study was to evaluate the effect for biodegradable screws containing bone morphogenetic protein-2 (BMP-2) in an osteoporotic rat model. Methods : Twenty-four female Wistar rat (250-300 g, 12 weeks of age) were randomized into four groups. Three groups underwent bilateral ovariectomy (OVX). Biodegradable screws with or without BMP-2 were inserted in the proximal tibia in two implantation groups. The extracted proximal metaphysis of the tibiae were scanned by exo-vivo micro-computed tomography. Evaluated parameters included bone mineral density (BMD), trabecular bone volume (BV/TV), trabecular number, trabecular thickness, and trabecular separation (Tb.Sp). The tibia samples were pathologically evaluated by staining with by Hematoxylin and Eosin, and trichrome. Results : Trabecular formation near screw insertion site was evident only in rats receiving BMP-2 screws. BMD and BV/TV significantly differed between controls and the OVX and OVX with screw groups. However, there were no significant differences between control and OVX with screw BMP groups. Tb.Sp significantly differed between control and OVX and OVX with screw groups (p<0.05), and between the OVX and OVX with screw BMP group (p<0.05), with no statistically significant difference between control and OVX with screw BMP groups. Over the 12 weeks after surgery, bone lamellae in direct contact with the screw developed more extensive and thicker trabecular bone around the implant in the OVX with screw BMP group compared to the OVX with screw group. Conclusion : Biodegradable screws containing BMP-2 improve nearby bone conditions and enhance ostoeintegration between the implant and the osteoporotic bone.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권4호
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• pp.250-254
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• 2010

Introduction: This study evaluated the bone regenerative effect of silk fibroin mixed with platelet-rich fibrin (PRF) of a bone defect in rabbits. Materials and Methods: Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter: 8.0 mm). The silk fibroin mixed with PRF was grafted into the right parietal bone (experimental group). The left side (control group) was grafted only PRF. The animals were sacrificed at 4 weeks and 8 weeks. A micro-computerized tomography (${\mu}$CT) of each specimen was taken. Subsequently, the specimens were decalcified and stained for histological analysis. Results: The average value of plane film analysis was higher in the experimental group than in the control group at 4 weeks and 8weeks after surgery. However, the difference was not statistically significant.(P>0.05) The tissue mineral density (TMD) in the experimental group at 4 weeks after surgery was significantly higher than the control group.(P<0.05) Conclusion: Silk fibroin can be used as a scaffold of PRF for rabbit calvarial defect repair.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.528-538
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• 2014

PURPOSE. The purpose of this prospective study was to evaluate the effectiveness of newly developed autogenous tooth bone graft material (AutoBT)application for sinus bone graft procedure. MATERIALS AND METHODS. The patients with less than 5.0 mm of residual bone height in maxillary posterior area were enrolled. For the sinus bone graft procedure, Bio-Oss was grafted in control group and AutoBT powder was grafted in experimental group. Clinical and radiographic examination were done for the comparison of grafted materials in sinus cavity between groups. At 4 months after sinus bone graft procedure, biopsy specimens were analyzed by microcomputed tomography and histomorphometric examination for the evaluation of healing state of bone graft site. RESULTS. In CT evaluation, there was no difference in bone density, bone height and sinus membrane thickness between groups. In microCT analysis, there was no difference in total bone volume, new bone volume, bone mineral density of new bone between groups. There was significant difference trabecular thickness ($0.07{\mu}m$ in Bio-Oss group Vs. $0.08{\mu}m$ in AutoBT group) (P=.006). In histomorphometric analysis, there was no difference in new bone formation, residual graft material, bone marrow space between groups. There was significant difference osteoid thickness ($8.35{\mu}m$ in Bio-Oss group Vs. $13.12{\mu}m$ in AutoBT group) (P=.025). CONCLUSION. AutoBT could be considered a viable alternative to the autogenous bone or other bone graft materials in sinus bone graft procedure.

• KIEAE Journal
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• 제14권3호
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• pp.105-109
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• 2014

The recent rising living standards, environment-friendly, well-being and health aspects of life in the basic gratification, as well as the desire for a pleasant environment emotionally environmentally friendly way of external space or industrial interest in the indoor environment, the manifestation. In particular, the biggest problem of the indoor environment has been emerged as a Sick House Syndrome indoor space that is provided to the building materials, and the impact on the domestic and the indoor environment, and clean the house in a health standards are specified as laws. The performance rating and the various materials to create environmentally-friendly standards for building materials. The more detail, Porous clay material, toxic substances released by applying the high humidity and the water itself, and to absorb the moisture, if the emissions, without a separate device, to maintain a comfortable indoor environment and at the same time, one of the causes of Sick House Syndrome breaking down harmful substances to absorb a comfortable indoor environment to maintain an environmentally-friendly building interior material studies. It is aimed at the development to multi-functional high performance eco-friendly construction materials, rather than through one feature performance, identify key features for national and international eco-friendly building materials can exert Water Vapour Adsorption raw, decomposed materials for the application and selection.

• Restorative Dentistry and Endodontics
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• 제43권3호
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• pp.24.1-24.12
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• 2018

Objectives: The aim of this in vitro study was to evaluate the biocompatibility of newly proposed root-end filling materials, Biodentine, Micro-Mega mineral trioxide aggregate (MM-MTA), polymethylmethacrylate (PMMA) bone cement, and Smart Dentin Replacement (SDR), in comparison with contemporary root-end filling materials, intermediate restorative material (IRM), Dyract compomer, ProRoot MTA (PMTA), and Vitrebond, using human periodontal ligament (hPDL) fibroblasts. Materials and Methods: Ten discs from each material were fabricated in sterile Teflon molds and 24-hour eluates were obtained from each root-end filling material in cell culture media after 1- or 3-day setting. hPDL fibroblasts were plated at a density of $5{\times}10^3/well$, and were incubated for 24 hours with 1:1, 1:2, 1:4, and 1:8 dilutions of eluates. Cell viability was evaluated by XTT assay. Data was statistically analysed. Apoptotic/necrotic activity of PDL cells exposed to material eluates was established by flow cytometry. Results: The Vitrebond and IRM were significantly more cytotoxic than the other root-end filling materials (p < 0.05). Those cells exposed to the Biodentine and Dyract compomer eluates showed the highest survival rates (p < 0.05), while the PMTA, MM-MTA, SDR, and PMMA groups exhibited similar cell viabilities. Three-day samples were more cytotoxic than 1-day samples (p < 0.05). Eluates from the cements at 1:1 dilution were significantly more cytotoxic (p < 0.05). Vitrebond induced cell necrosis as indicated by flow cytometry. Conclusions: This in vitro study demonstrated that Biodentine and Compomer were more biocompatible than the other root-end filling materials. Vitrebond eluate caused necrotic cell death.

• 대한화학회지
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• 제46권2호
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• pp.125-138
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• 2002

15세기 전반에 70-80년 동안 분청과 백자를 생산한 전라남도 광주시 충효동 가마터에 대하여 여러 가지 과학기술적 상황들을 조사하였다. 발굴된 위치와 퇴적층의 층위에 따라 일곱 그룹으로 나눈 분청사기의 태토와 유약 원료에 대하여 광물성분의 특징을 조사하고, 미세구조와 번조온도를 분석하여 제작 당시의 원료선택과 처리과정, 그리고 번조공정 등의 제작기술의 변화과정을 살펴보았다. 도편의 미세구조는 광학현미경과 전자현미분석장치로, 그리고 광물성분은 X-선 회절분석기와 편광현미경으로 관찰하였다. 번조온도 측정은 재번조한 후의 미세구조 변화를 관찰하는 방법을 이용하였다. CHE2그룹과 같이 왕실을 위한 최상급의 제품들도 있었지만 대중화되고 백자에 대한 선호도가 증가하면서 분청의 질이 많이 떨어진 것을 볼 수 있었다. 모두 이 지역 여러 종류의 흙을 태토와 유약원료로 사용하였으며 1100와 1225$^{\circ}C$사이에서 번조한 것으로 추정되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.377-383
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• 2012

Purpose: The aim of this study was to evaluate the effect of 4-hexylresorcinol and hydroxyapatite combination graft on bone regeneration in the rabbit calvarial defect model. Methods: Ten New Zealand white rabbits were used for this study. Bilateral round shaped defects (diameter: 8.0 mm) were created on the parietal bone. 4-hexylresorcinol and hydroxyapatite combination graft material was grafted into the right parietal bone defect area (experimental). The left bone defect area was not filled with anything (control). The animals were sacrificed at 4 weeks and 8 weeks after grafting. A micro-computerized tomography of each specimen was taken, and the specimens were stained for histological analysis. Results: The average value of bone mineral density (BMD) and Bone volume (BV) was higher in the experimental group than in the control group at 4 weeks and 8 weeks after surgery. However, the difference was not statistically significant (P>0.05) at 8 weeks after grafting. The BMD and BV in the experimental group at 4 weeks after surgery was significantly higher than those in the control group (P<0.05). Conclusion: 4-hexylresorcinol and hydroxyapatite combination graft material showed higher initial bone formation than the control, however, there was no difference at 8weeks after operation.

• Journal of Periodontal and Implant Science
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• 제40권5호
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• pp.220-226
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• 2010

Purpose: This study was performed to evaluate the periodontal wound healing effect of particulate equine bone mineral on canine alveolar bone defects. Methods: Twelve adult male beagle dogs were used as study subjects. The mandibular second and fourth premolars were extracted prior to the experimental surgery, and the extraction sites were allowed to heal for 8 weeks. After periodontal probing, two-walled defects were created at the mesial and distal sides of the mandibular third premolars bilaterally, and the defects were filled with equine particulate bone with collagen membrane or bovine particulate bone with collagen membrane, or collagen membrane alone. The defects without any treatment served as negative controls. After probing depth measurement, animals were sacrificed at 10, 16, and 24 post-surgery weeks for micro-computed tomographic and histomorphometric analysis. Results: The equine particulate bone-inserted group showed significantly decreased values of probing depth and first bone contact compared to the negative control and collagen membrane alone groups at weeks 10, 16, and 24 (P<0.05). There were no significant differences in the new cementum length, newly-formed bone area, or newly-formed bone volume between equine particulate bone- and bovine particulate bone-inserted groups, both of which showed significantly increased values compared to the negative control and collagen membrane alone groups (P<0.05). Conclusions: Equine particulate bone showed significant differences in probing depth, first bone contact, new cementum length, newly formed bone area, and bone volume fraction values when compared to the negative control and collagen membrane alone groups. There were no significant differences between equine and bovine particulate bone substitutes in these parameters; therefore, we can conclude that equine particulate bone is equivalent to bovine bone for periodontal regeneration.

• 한국세라믹학회지
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• 제51권6호
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• pp.584-590
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• 2014

Air-cooled slag showed grindability approximately twice as good as that of water-cooled slag. While the studied water-cooled slag was composed of glass as constituent mineral, the air-cooled slag was mainly composed of melilite. It is assumed that the sulfur in air-cooled slag is mainly in the form of CaS, which is oxidized into $CaS_2O_3$ when in contact with air. $CaS_2O_3$, then, is released mainly as $S_2O{_3}^{2-}$ion when in contact with water. However, the sulfur in water-cooled slag functioned as a constituent of the glass structure, so the$S_2O{_3}^{2-}$ ion was not released even when in contact with water. When no chemical admixture was added, the blended cement of air-cooled slag showed higher fluidity and retention effect than those of the blended cement of the water-cooled slag. It seems that these discrepancies are caused by the initial hydration inhibition effect of cement by the $S_2O{_3}^{2-}$ ion of air-cooled slag. When a superplasticizer is added, the air-cooled slag used more superplasticizer than did the blast furnace slag for the same flow because the air-cooled slag had higher specific surface area due to the presence of micro-pores. Meanwhile, the blended cement of the air-cooled slag showed a greater fluidity retention effect than that of the blended cement of the water-cooled slag. This may be a combined effect of the increased use of superplasticizer and the presence of released $S_2O{_3}^{2-}$ ion; however, further, more detailed studies will need to be conducted.