• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권5호
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• pp.293-298
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• 2012

Purpose: The aim of this study was to evaluate the bone regeneration ability of 1% tetracycline (TC)-loaded silk fibroin membrane (SFM), in a rabbit calvarial defect model. Methods: Twenty New Zealand white rabbits were used for this study. Bilateral round defects were made on the rabbit parietal bone, using trephine bur with an 8 mm diameter. TC-loaded SFM or SFM was covered on the right parietal bone defect, and the left parietal bone defects were uncovered for the control. The animals were humanely sacrificed at 4 or 8 weeks postoperatively. A micro-computerized tomography (${\mu}$-CT) of each specimen was taken for analysis of bone regeneration. Hematoxylin and Eosin stain were done to observe histological findings. Results: From the ${\mu}$-CT results, regenerated bone volume ($mm^3$) of 1% TC-loaded SFM, SFM, and control were $7.80{\pm}5.87$, $8.79{\pm}3.44$, and $10.61{\pm}5.3$ at 4 weeks postoperatively, respectively (P>0.05). Regenerated bone volume ($mm^3$) of 1% TC-loaded SFM, SFM, and control were $36.56{\pm}8.50$, $25.86{\pm}8.17$, and $19.09{\pm}5.07$ at 8 weeks postoperatively, respectively (P<0.05). Conclusion: The 1% TC-loaded SFM showed more bone regeneration than the SFM and the uncovered control, in guided bone regeneration.

• Journal of Ecology and Environment
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• 제29권2호
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• pp.113-124
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• 2006

Landscape structure, habitat types, vegetation structure and biodiversity in the Bokha stream chosen as a reference stream were investigated to get ecological information necessary for restoration of urban stream degraded by excessive artificial interference. Landscape structure showed a slight change between before and after flooding. Habitat types of nine sorts were identified based on ecological information obtained from field survey such as micro-topography, hydrological characteristics, disturbance regime, and so on. Each habitat holds specific organisms to each site. Consequently, the number of plant communities, and species of benthos and fish increased as the kinds of habitat type increase. Ordination of habitat types based on vegetation, benthos, and fish data reorganized them into three groups of pool types of two kinds depending on whether they are connected to the water course or not and riffle one. Vegetation showed different stratification and species composition depending on topographical position in relation to disturbance cycle. Based on the results from this study, relationship between environmental heterogeneity and biodiversity was discussed and a restoration plan was suggested in a viewpoint of vegetation.

• 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.

• Nuclear Engineering and Technology
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• 제21권3호
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• pp.165-170
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• 1989

준 동적 파괴가 일어나는 변형율속도 조건에서 A533B-1 원자로 압력용기강의 파괴인성 및 파괴저항특성에 미치는 변형율속도의 영향을 균열선단의 강 소성역 관찰 및 파면의 미세거칠기측정을 통해 연구하였다. 1/2T-CT 파괴시편에서 약 1.5mm 이하의 균열진전에 대해서는 소성일로 부터 구한 J와 수정 J가 거의 일치하였다. 파면의 미세거칠기로부터 구한 국부 변형율은 1.8-2.0 정도의 값을 나타내어 거시적으로 측정된 값보다 높은 값을 보여주었다. 이들 방법은 모두 변형율속도가 증가함에 따라 파괴인성은 증가하나 tearing modulus는 큰 변화가 없음을 보여주었다.

• 구강회복응용과학지
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• 제32권3호
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• pp.158-168
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• 2016

본 논문은 기존에 선행되었던 연구들을 바탕으로 고정성 보철물의 내면 및 변연적합도를 평가하는 여러 가지 방법에 관하여 정리하였으며, 각 방법에 대한 장, 단점에 대해 언급하였다. 보철물의 적합도를 평가하는 방법은 크게 임상적 평가법과 실험실 평가법으로 분류할 수 있다. 임상적 평가법에는 탐침 검사법, 방사선 사진 검사법, 인상채득법이 있으며, 실험실 평가법에는 현미경을 이용하는 변연부 측정법, 절단면 측정법, 실리콘 복제 측정법, 그리고 마이크로 CT나 조면계를 사용하여 측정하는 방법 등이 있다. 최근 스캐닝 기법이 발전하면서 내면 및 변연적합도를 3차원적으로 평가하는 것이 가능해졌으며, 앞으로 측정법 및 분석법의 개발에 따라 보철물의 적합도 평가가 더욱 간편해지고 효과적으로 변화할 것이라 생각된다.

• 자원리싸이클링
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• 제26권6호
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• pp.97-101
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• 2017

메탈폼은 매우 많은 기공을 포함하는 세포상 구조를 갖는 고체금속을 일컫는다. 특히 관통 기공 같은 개기공들은 고온용 필터 및 촉매 지지체 등으로 산업적으로 많이 사용되고 있다. 본 연구에서는 슬러리 코팅공정으로 90% 이상의 기공율과 2 mm 이상의 기공크기를 갖는 Fe 폼을 제조하였다. 이때 Fe 분말과 $Fe_2O_3$ 분말의 혼합비를 달리하여 기공율과 기공크기를 제어하였다. 이를 위해 우선 분말, 증류수 및 폴리비닐알콜(PVA)를 균일하게 혼합하여 슬러리를 제조하였다. $Fe_2O_3$ 분말의 혼합 비율이 증가할수록 PU 폼에 코팅된 슬러리의 양이 증가한 반면 Fe 폼의 수축 및 기공율은 각각 감소하였다.

• Biomolecules & Therapeutics
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• 제22권6호
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• pp.563-569
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• 2014

Materials with differing surfaces have been developed for clinical implant therapy in dentistry and orthopedics. This study was designed to evaluate bone response to titanium alloy containing Ti-32Nb-5Zr with nanostructure, anodic oxidation, heat treatment, and ibandronate coating. Rats were randomly assigned to two groups for implantation of titanium alloy (untreated) as the control group and titanium alloy group coated with ibandronate as the experimental group. Then, the implants were inserted in both tibiae of the rats for four weeks. After implantation, bone implant interface, trabecular microstructure, mechanical fixation was evaluated by histology, micro-computed tomography (${\mu}CT$) and the push-out test, respectively. We found that the anodized, heat-treated and ibandronate-coated titanium alloy triggered pronounced bone implant integration and early bone formation. Ibandronate-coated implants showed elevated values for removal torque and a higher level of BV/TV, trabecular thickness and separation upon analysis with ${\mu}CT$ and mechanical testing. Similarly, higher bone contact and a larger percentage bone area were observed via histology compared to untreated alloy. Furthermore, well coating of ibandronate with alloy was observed by vitro releasing experiment. Our study provided evidences that the coating of bisphosphonate onto the anodized and heat-treated nanostructure of titanium alloy had a positive effect on implant fixation.

• 대한방사성의약품학회지
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• 제5권1호
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• pp.54-60
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• 2019

Sentinel lymph node (SLN) imaging plays an important role in surgery of patients with breast cancer and melanoma. In this study, avidin (Av), a tetrameric protein glycosylated with mannose and N-acetylglucosamine molecules, was labeled with $^{64}Cu$ and then evaluated for LN imaging. $^{64}Cu$-Labeled $NeutrAvidin^{TM}$ (NAv), a non-glycosylated form of Av, was used for comparison. 1,4,7,10-Tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-conjugated Av and NAv were prepared from the corresponding proteins and DOTA-NHS ester, which were then labeled with copper-64 and purified using PD-10 columns. The numbers of DOTA molecules conjugated to Av and NAv were 4.9 and 3.3, respectively. [$^{64}Cu$]Cu-DOTA-conjugated Av and NAv were prepared in 93% and 73% radiochemical yields, respectively. In vitro serum stability study showed that copper-64 remained stable on all radiotracers for 24 h (>97%). MicroPET/CT images showed that high radioactivity was accumulated in LNs within 15 min after footpad-injection of radiotracers. Tissue distribution data of mice demonstrated significantly higher uptake in the popliteal (PO) LN than lumbar (LU) LN for $^{64}Cu$-labeled Av (relative % ID/g excluding the injection sites: 66.2% and 26.0%, respectively) compared with those of $^{64}Cu$-labeled NAv (43.0% and 49.2%, respectively). The results of this study suggest that mannose molecules on Av enabled the radiotracer to retain in the first LN after mouse footpad-injection.

• Journal of Korean Dental Science
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• 제14권1호
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• pp.12-25
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• 2021

Purpose: (i) To evaluate the biologic properties of a bi-layered 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride-cross-linked collagen membrane (CCM) in vitro. (ii) To assess the efficacy of CCM for localized bone regeneration in vivo. Materials and Methods: Biodegradation of CCM compared to a native collagen membrane (NCM) was assessed in vitro. In vivo, twelve male New Zealand White rabbits were used. Four calvarial, circular defects (diameter 8 mm) were created in each animal. The sites were randomly allocated to i) CCM+biphasic calcium phosphate (BCP) (CCM-BCP group), ii) CCM alone (CCM), iii) BCP alone (BCP) and, iv) negative control (control). Animals were sacrificed at 2 (n=6) and 8 weeks (n=6). Outcome measures included: micro-computed tomography (μCT) analysis (total augmented volume [TAV], new bone volume) and histomorphometry (total augmented area [TAA], newly formed bone, remaining membrane thickness [RMT]). Result: CCM was more resistant to degradation than NCM. μCT analysis showed CCM-BCP (196.43±25.30 mm³) and BCP (206.23±39.13 mm³) groups had significantly (P<0.01) larger TAV than the control (149.72±12.28 mm³) after 8 weeks. Histomorphometrically, CCM-BCP group (17.75±5.97 mm²) had significantly (P<0.01) greater TAA compared to the CCM group (7.74±2.25 mm²) and the control (8.13±1.81 mm²) after 8 weeks. After 8 weeks, RMT was reduced by 67%. Conclusion: CCM can be a favorable choice of barrier membrane when performing guided bone regeneration (GBR) in localized bone defects. CCM has better resistance to degradation than the natural collagen membrane, in vitro. In vivo, CCM provides an advantageous integration of prolonged barrier function and biocompatibility for GBR.

• Korean Circulation Journal
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• 제54권8호
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• pp.499-512
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• 2024

Background and Objectives: Arterial dissection during endovascular therapy rarely occurs but can be lethal. A fabric-based covered graft stents yield poor clinical outcomes. A novel balloon-expandable stent with biodegradable film graft for overcoming these issues was evaluated in a rabbit iliac artery model. Method: Eighteen rabbits with iliac artery dissections were induced by balloon over-inflation on angiography (Ellis type 2 or 3) and treated using the test device (3.0×24 mm). Subsequently, survived twelve animals underwent histologic examinations and micro-computed tomography (CT) at 0, 2, 4, and 8 weeks and 3, 6, 9, and 12 months and angiography at one-year. Results: There were no adverse cardiovascular events during the one-year. Early-stage histologic examination revealed complete sealing of disrupted vessels by the device, exhibiting mural hematoma, peri-stent red thrombi, and dense infiltration of inflammatory cells. Mid- and long-term histologic examination showed patent stents with neointimal hyperplasia over the stents (% area stenosis: 11.8 at 2 weeks, 26.1 at 1 month, 29.7 at 3 months, 49.2 at 9 months, and 51.0 at 1 year), along with mild peri-strut inflammatory response (Grade: 1-2 at mid-term and 0-1 at long-term). The graft film became scarcely visible after six months. Both CT and angiography revealed no instances of thrombotic occlusion or in-stent restenosis (% diameter stenosis: 5.7 at 2 weeks, 12.3 at 1 month, 14.2 at 3 months, 25.1 at 9 months, and 26.6 at 1 year). Conclusions: The novel balloon-expandable stent with a biodegradable film graft demonstrates feasibility in managing severe artery dissection and preventing lethal vascular events in animal model.