• 치과방사선
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• 제21권1호
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• pp.83-89
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• 1991

This study was performed to simulate various sizes of periapical lesions and condensing osteitis in bone and to clarify that condensing osteitis would give a greater radiographic contrast because of the more radiopacity immediately adjacent to the lesion and what the lamina dura on radiogram is in bone. For this study, two dry and wet human adult mandible and a cadaver were used. Each mandible was sectioned longitudinally to split lingual and buccal cortical plates to gain better access to the apex of tooth. Lesions were gradually enlarged and bordered with tooth ash that burned out at 950℃ for the reproduction of condensing osteitis in sequence. The serial radiograms were taken under the constantly maintained condition and compared with the actual lesions.

• 한국동물위생학회지
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• 제24권1호
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• pp.95-99
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• 2001

In order to clarify the cadmium(Cd) contents of normal deer, tissue samples including kidney, liver, muscle, spleen, heart, lung, rumen, abomasum, intestine, skin and bone were collected from 18 deer which were slaughtered in Korea. All samples were burned to ashes and analyzed for Cd contents by atomic absorption spectrophotometric method. The mean Cd contents in \mu\textrm{g}$/g wet matter for 18 deer were liver 0.013, kidney 0.286, muscle 0.010, spleen 0.001, heart 0.007, lung 0.005, men 0.019, abomasum 0.016, intestine 0.018, skin 0.016 and bone 0.312, respectively. Two samples in kidney, one sample in muscle out of 18 deer showed higher Cd contents than normal limit value of 0.50\mu\textrm{g}$/g for liver and kidney, 0.10\mu\textrm{g}$/g for muscle. In addition, three deer also showed higher Cd contents in one body tissue than normal limit value which reported foreign countries.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.181-185
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• 2003

The composite structural system with reinforced concrete column and steel beam has some advantages in the structural efficiency by complementing the shortcomings between the two systems. The system, however, has also a lot of problems in earthquake-proof capacity and construction process because it is wet method of construction. So, this paper proposed PCS(Precast Concrete Column and Steel Beam) structural system with dry method of construction. Purpose of this study is to enhance merit and control failure mechanism by installing Dog-Bone on H-beam.

• Advances in materials Research
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• 제4권4호
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• pp.193-205
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• 2015

Contamination by bacterial strands is a major problem after bone replacement surgeries, so there is a great need to develop low cost biocompatible antibacterial bioactive scaffolds to be used in bone tissue engineering. For this purpose, nano-zinc doped hydroxyapatite with different zinc-concentrations (5, 10 and 15 mol%) was successfully prepared by the wet chemical precipitation method. The prepared powders were used to form porous scaffolds containing biodegradable Ca-cross-linked alginate (5%) in order to enhance the properties of alginate scaffolds. The scaffolds were prepared using the freeze-gelation method. The prepared powders were tested by X-ray diffraction; transmission electron microscope and Fourier transform infrared analyses, while the prepared scaffolds were investigated by Fourier transform infrared analyses, thermogravimetric analyses and measurement of the antibacterial properties. Best results were obtained from scaffold containing 15% mol zinc-doped hydroxyapatite powders and 5% alginate concentration with ratio of 70:30.

• 한국분말재료학회지
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• 제27권6호
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• pp.468-476
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• 2020

The bone cement used for vertebroplasty must be sufficiently injectable. The introduction of granules reduces the amount of liquid required for liquefaction, implying that higher fluidity is achieved with the same amount of liquid. By employing β-tricalcium phosphate granules with an average diameter of 50 ㎛, changes in injectability are observed based on the paste preparation route and granular fraction. To obtain acceptable injectability, phase separation must be suppressed during injection, and sufficient capillary pressure to combine powder and liquid must work evenly throughout the paste. To achieve this, the granules should be evenly distributed. Reduced injection rates are observed for dry mixing and excessive granular content, owing to phase separation. All these correspond to conditions under which the clustered granules weakened the capillary pressure. The injected ratio of the paste formed by wet mixing displayed an inverted U-type shift with the granular fraction. The mixture of granules and powder resulted in an increase in the solid volume fraction, and a decrease in the liquid limit. This resulted in the enhancement of the liquidity, owing to the added liquid. It is inferred that the addition of granules improves the injectability, provided that the capillary pressure in the paste is maintained.

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.122-133
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• 2014

Purpose: This study was to develop an effective process for fabricating biocompatible calcium phosphate powders (CPPs) using horse bones, and to investigate the characteristics of them. Methods: The characteristics of horse bone powders (HBPs) were investigated according to the different osseous tissue types (compact bone and cancellous bone), bone types (spine and tibia), pretreatment methods (cold water, $H_2O_2$, and hot water), sintering time (4, 8 and 12h), and sintering temperature (600, 900, 1100 and $1300^{\circ}C$). In addition, the grinding methods were compared based on the wet grinding (ball mill) and dry grinding (blade grinder) method to make it as powders. Finally, their cytotoxicity and cell viability were checked. Results: Regardless of the types of osseous tissues and bones, HBPs were well fabricated as biocompatible CPPs. It was also found that the pretreatment methods did not influence on the resultants, showing well-fabricated HBPs. Considering the processing time, the hot water method was the most suitable compared to other pretreatment methods. Further, 12h-sintering time was sufficient to remove residual organic compounds. The sintering temperatures greatly affected the properties of bone powders fabricated. The x-ray diffraction (XRD) peak of horse bone sintered at $600^{\circ}C$ was most closed to that of hydroxyapatite (HA). Our bioactivity study demonstrated that the HBPs fabricated by sintering horse bones at $1300^{\circ}C$ showed the best performance in terms of cell viability whereas the HBPs $1100^{\circ}C$ showed the cytotoxicity. Conclusions: Using various types of horse bone tissues, biocompatible CPPs were successfully developed. We conclude that the HBPs may have a great potential as biomaterials for various biological applications including bone tissue engineering.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.484-495
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• 2015

PURPOSE. This study was to evaluate the effects of bacterial cellulose (BC) membranes as a barrier membrane on guided bone regeneration (GBR) in comparison with those of the resorbable collagen membranes. MATERIALS AND METHODS. BC membranes were fabricated using biomimetic technology. Surface properties were analyzed, Mechanical properties were measured, in vitro cell proliferation test were performed with NIH3T3 cells and in vivo study were performed with rat calvarial defect and histomorphometric analysis was done. The Mann-Whitney U test and the Wilcoxon signed rank test was used (${\alpha}<.05$). RESULTS. BC membrane showed significantly higher mechanical properties such as wet tensile strength than collagen membrane and represented a three-dimensional multilayered structure cross-linked by nano-fibers with 60 % porosity. In vitro study, cell adhesion and proliferation were observed on BC membrane. However, morphology of the cells was found to be less differentiated, and the cell proliferation rate was lower than those of the cells on collagen membrane. In vivo study, the grafted BC membrane did not induce inflammatory response, and maintained adequate space for bone regeneration. An amount of new bone formation in defect region loaded with BC membrane was significantly similar to that of collagen membrane application. CONCLUSION. BC membrane has potential to be used as a barrier membrane, and efficacy of the membrane on GBR is comparable to that of collagen membrane.

• 한국식품영양과학회지
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• 제26권2호
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• pp.334-343
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• 1997

본 연구는 폐경 후 여성에게 식이 칼슘염 형태, 에스트로겐 및 에스트로겐/칼슘 혼합요법이 골격 구성 성분에 미치는 영향을 알아보고자 난소절제쥐를 이용한 총 9군으로 분류하여 6주간 사육한 후 그 효과를 살펴보았다. 오른쪽 대퇴골의 젖은 무게, 밀도, 길이, 강도, 회분 함량은 난소를 절제한 군과 난소를 절제하지 않은 군간에 차이는 없었다. 그러나 대퇴골의 젖은 무게는 체중 당으로 표현한 값은 난소를 절제한 군에서 낮았다. 이것은 난소를 절제한 쥐의 체중부하로 인해 골격 구성 성분은 변화가 없는 것으로 사료된다. 난소절제 후 estrogen 투여, estrogen/칼슘 혼합군에서 체중당 젖은 무게는 증가함을 보여 주었다. 난소절제 후 estrogen 점진적 감소군에서 강도, 회분 함량, 칼슘 함량, 인 함량이 가장 낮았다. 견갑골의 젖은 무게, 밀도, 회분 함량, 칼슘 함량, 인 함량은 난소를 절제한 군과 난소를 절제하지 않은 군간에 차이는 없었다. 난소절제 후 estrogen 점진적 감소군에서 뼈의 젖은 무게와 회분 함량이 모든군에 비해 낮았고 고칼슘을 투여하거나, 칼슘을 점진적으로 증가시키는 것이 골손실을 다소 감소시킴을 알 수 있었다. 이상의 성적으로 보아 난소절제 여부에 따른 골격구성 성분에는 변화가 없었다. 난소절제 후 estrogen 및 estrogen/칼슘 혼합요법 골격손실을 상당량 방지 할 수 있었고 estrogen 점진적 감소군은 골격손실을 가져옮을 알 수 있었다. Estrogen 점진적 감소에 고칼슘, 칼슘 점진적 증가투여는 골격 구성 성분의 손실을 다소 방지할 수 있음을 알 수 있었다.

• The Korean Journal of Ecology
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• 제25권5호
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• pp.329-334
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• 2002

본 연구는 중금속 오염 모니터링의 일환으로 섬 지역(경기도 덕적도), 도심지역(서울), 공단 지역(여천, 안산, 울산, 부산)에서 서식하는 비둘기(Columba livia)의 체내 조직 중 납과 카드뮴 농도를 측정하고, 각 지역의 중금속 오염 정도를 비교, 평가한 것이다. 도심지역과 공단지역에 서식하는 비둘기 체내 납과 카드뮴 농도는 섬 지역에 비해 신장, 뼈, 간, 허파의 모든 조직에서 높은 것으로 나타났다. 특히, 납은 뼈 조직에서, 카드뮴은 신장 조직에서 각각 섬 지역의 평균 1.80㎍/wet g, 0.06㎍/wet g보다 도심 및 공단지역이 10배 이상 높았다. 다만, 여천 공단지역의 뼈 조직내 납 농도는 다른 공단지역에 비해 현저히 낮았으며, 섬 지역과 비슷한 농도가 검출되었다. 이러한 결과는 먹이 및 먹이와 함께 섭취한 모래알갱이에 부착된 오염 물질뿐만 아니라 대기 오염 농도와도 관계가 있는 것으로 나타났다.

• 공업화학
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• 제8권6호
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• pp.1000-1005
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• 1997

참치 뼈로부터 추출한 hydroxyapatite[$Ca_{10}(PO_4)_6(OH)_2$]를 습식법으로 분쇄한 후 여러 온도로 고상반응시킨 세라믹 소결체의 특성을 고찰하였다. Hydroxyapatite소결체의 밀도는 $1350^{\circ}C$에서 약 $2.93g/cm^3$으로서 이론치의 $3.21g/cm^3$과 유사하였다. $1300^{\circ}C$ 이하의 소결온도에서는 hydroxyapatite가 결정상으로 나타났으며, 온도가 증가할수록 hydroxyapatite의 분해에 따른 whitlockite[$Ca_3(PO_4)_2$]의 결정상이 관찰되었다. 소결채의 미세구조는 발달된 입계들 사이에 폐기공들이 분포하였다. $1350^{\circ}C$의 소결시편 평균강도는 58MPa로 나타나 관절연골(articular cartilage)의 최대강도인 40MPa보다 우수한 것으로 나타났다.