• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제36권3호
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• pp.271-278
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• 2008

A study has been conducted on the bulging process of liquid rocket engine nozzle which is essential to the manufacturing regenerative cooling combustion chamber. Mechanical properties of the material used for the bulging were experimentally obtained by tension tests. Deformation of the bulged nozzle was confirmed by a structural analysis. The developed bulging process and the deformation analysis result were confirmed by manufacturing of the bulged nozzle specimens and the bulging test. There has been a bulging failure among 7 bulged specimens due to the necking of the material. The cause of necking was investigated by comparing microstructure of the material. The investigation has revealed grain size of the material has considerable effect on the occurrence of the necking.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 한국GIS학회 2010년도 추계학술대회
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• pp.147-148
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• 2010

낙후된 도시를 정비하는 방법으로 새로이 등장한 거점확산형 주거환경개선사업은 전면철거방식인 주택재개발사업이내 공동주택 건설방식과 비교하여 지역주민의 재정착 비율이 높고, 기존 도시 조직을 고려하며 점진적으로 개발할 수 있는 기성시가지 정비수법으로 주목받아 왔다. 또한 지역의 침체된 경제를 활성화시키고 황폐화된 구시가지를 회복시키기 위하여 정부에서는 도시의 새로운 경쟁력을 찾고 지역 주민의 삶의 질을 보장하기 위해 지역 주민의 삶의 질을 보장하기 위해 지역 커뮤니티를 근간으로 하는 도시재생사업을 추진하게 되었다. 효과적인 거점확산형 주거환경개선사업을 위해서는 주민참여가 중요하며, 현재에 이르러서는 필수적인 요건이 되었고, 도시계획 역시 주민과 함께 하는 방향으로 변화하게 되었다. 이에 따라 GIS도 주민과 같은 비전문가의 의사결정을 지원하기 위한 도구로 확대되어 활용되고 있다 하지만, 현행 주민참여 방식은 형식적인 수단에 불과하며, 주민 참여도를 높일 수 있는 획기적인 방법은 아직도 연구해야할 과제이다. 따라서 본 연구에서는 커뮤니티의 재생을 목적으로 하는 거점확산형 주거환경개선사업에서 능동적 주민참여를 좀 더 효율적으로 이끌어 내고자 사업정보제공서비스, 주민의사반영 서비스, 쌍방향적 의견교환서비스, GIS 서비스를 제공하는 커뮤니티 재생을 위한 앱 기반 PPGIS 모델을 제안하였다. 최근 스마트폰의 보급률이 급증함에 따라 스마트폰의 활용은 주민들의 관심과 참여 비율의 변화를 크게 가져올 수 있을 것으로 기대되며, 커뮤니티 재생을 위한 스마트폰의 앱 기반 PPGIS 모델은 정책결정자, 전문가 그리고 주민이 서로의 생각을 교환하고 이해하는데 또 다른 유용한 의사소통 도구가 되어 주민의 참여도를 높여 줄 것이라 기대된다 특히, 스마트폰을 많이 사용하고 있는 젊은층의 흥미를 유발하여 참여도가 낮은 젊은층의 참여도를 높이는데 기여할 것이라 여겨진다,

• Journal of the Korean Society of Radiology
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• 제15권4호
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• pp.539-545
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• 2021

Radiation therapy is accompanied by adverse radiation effective. In particular, it is accompanied by disorders of the vascular system. Therefore, oxygen and nutrient deficiency occurs in the regeneration area. Eventually, osteoradionecrosis is formed in this cellular environment. According to a precedent study, bone morphogenetic protein-2 is used to overcome osteoradionecrosis. The purpose of this study was to investigate the regeneration ability of osteoradionecrosis by treating bone-forming protein-2 on a fibrinogen scaffold which is a biomaterial that is frequently used for bone regeneration after irradiation of the rat head. In addition, the purpose of this study was to verify the bone regeneration effect from the eight weeks. According to the experimental results, in the calvarial defected model of the irradiated mouse, making bone-formation was obtained after 8 weeks rather than bone-formation period in the early 4 weeks. moreover, it was found that the regenerated bone formation of the fibrinogen scaffold is formed from the inside of the bone of the defect area.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.113-126
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• 2004

연구목적 : 이번 실험의 목적은 외과적으로 형성된 성견의 1면 골내낭에 새롭게 제조된, Ca/P 비율이 0.6인 비결정성 calcium phosphate를 적용하였을 때 치주조직의 재생에 미치는 영향을 평가하는 것이다. 연구방법 : 6마리 성견의 양측 하악 제2소구치의 원심면, 제4소구치의 근섬면에 외과적으로 1면 골내낭을 형성하여 치은박리소파술을 시행한 부위를 대조군으로, calcium phosphate만을 이식한 부위를 실험 1군, calcium phosphate와 GTR을 동반한 부위를 실험 2군으로 설정하고 실험하여 술 후 8주에 치유결과를 조직학적으로 관찰하였다. 결론 : 1. 접합상피의 치근단 이동은 대조군에서 결손부 깊이의 30.90 ${\pm}$ 9.92%, 실험 1군에서 결손부 깊이의 24.08 ${\pm}$ 9.12%, 실험 2군에서 결손부 깊이의 38.68 ${\pm}$ 12.22%로 나타났으며 대조군과 실험 1,2군간에 통계적 유의차는 없었다. 2. 결합조직 유착은 대조군에서 결손부 깊이의 36.38 ${\pm}$ 9.03%, 실험 1군에서 결손부 깊이의 26.96 ${\pm}$ 4.24%, 실험 2군에서 결손부 깊이의 27.87 ${\pm}$ 9.70%로 나타났으며 대조군과 실험 1,2군간에 통계적 유의차는 없었다. 3. 신생백악질 형성은 대조군에서 결손부 깊이의 32.92 ${\pm}$ 10.51%, 실험 1군에서 결손부 깊이의 49.16 ${\pm}$ 12.70%, 실험 2군에서 결손부 깊이의 39.62 ${\pm}$ 12.14%로 나타났으며 대조군과 실험 1군간에 통계적 유의차가 있었다. 4. 신생골 형성은 대조군에서 결손부 깊이의 27.24 ${\pm}$ 7.49%, 실험 1군에서 결손부 깊이의 43.51 ${\pm}$ 13.34%, 실험 2군에서 결손부 깊이의 36.47 ${\pm}$ 15.11%로 나타났으며 대조군과 실험 1, 2군간에 통계적 유의차는 없었다. 이상의 결과에서 볼 때, calcium phosphate glasses는 신생골 형성에는 통계적으로 유의차는 없었지만 상당히 증가된 양상을 보였고 신생백악질 형성에는 크게 기여함을 알수 있었다.

• The Korean Journal of Zoology
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• 제39권4호
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• pp.426-436
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• 1996

In previous studies, we have shown that lysosomal add phosphatase (LAP) activity increases at the dedifferentiation stage in the regenerating larval limbs of salamander, Hynobius leechii. Monoclonal antibodies against LAP were generated to determIne the spatial and temporal distribution of the protein In the regenerates.A total of 22 monoclonal antihodies recognizIng different epftopes of the protein were obtained, of which five strongly stained the regenerating limb by imunohistochemistry. in LAP immunohistochemical examination, LAP showed distribution coincident with the state of dedifferentiation, both spatially and temporally, in the limb regenerates. When unfractioned protein of regenerating salamander limbs were separated by gel electrophoresis and immunoblotted, the antibodies recognized a single protein band of 53 kl)a, which comigrates with a monomerlc subunit of IAR Using the anti-IAP antibodIes as probe, we investigated the cross-reactivities of LAPs from other sources. The immunoreadive bands on Western blots appeared to be the same In molecular mass-53 kl)a in axoloti and Xenopus, but no protein band was detected in mouse, Drosophila, or C. elegans.These results show that the antibodies generated in this study spedfically recognize Hynoblus leeclili IAp and that IAPs may be highiy conserved among amphibians. Furthermore, the distdbution of the protein is consistent with a role for LAP in the dedifferentiation process of limb regeneration.

• Polymer(Korea)
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• 제34권3호
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• pp.185-190
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• 2010

Recently, an electrospinning process, which is one of various nanotechnologies, has been used in fabricating micro/nanosized fibers. The fabricated electrospun micro/nanofibers has been widely applied in biomedical applications, specially in tissue regeneration. In this study, we fabricated highly aligned electrospun biodegradable and biocompatible poly(${\varepsilon}$-caprolactone)(PCL) micro/nanofibers by using a modified electrospinning process supplemented with a complex electric field. From this process, we can attain highly aligned electrospun nanofibers compared to that fabricated with the normal electrospinning process. To observe the feasibility of the highly aligned electrospun mat as a biomedical scaffold, nerve cells(PC-12) was cultured and it was found that the cells those were well oriented to the direction of aligned fibers.

• Applied Microscopy
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• 제34권3호
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• pp.199-209
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• 2004

The migut epitheluim of the last instar larva in the mosquito larvae, Anopheles sinensis was observed with electron microscopes. The midgut epitheluim of the mosquito larva is composed of a single-layered columnar absorptive cells, regenerative cells and secretory granular cells. The free surface of the columnar absorptive cells has a regular array of microvilli 'brush border', while cell membranes close to the basal lamina are extrmely infolded and a lot of mitochondria are concentrated in those processes. The columnar absorptive cells also contain cell organelles expected to be found in absorptive cell. Midgut regenerative cells which are positioned basally in the epithelium form the groups, which are called 'nidi', composed of 1 or $2{\sim}3$ cells, they show darker appearance than the columnar absoptive cells. The secretory granular cells contain numerous electron dense granules, $200{\sim}400$ nm in diameter. The cone shaped secretory granular cells are located in the basal portion of the midgut epitheluim. The epithelium is surrounded by the subepithelial space and muscle bundles. The subepithelial space, which is filled with fibrous connective tissue, is innervated by many axon cells and tracheoles.

• Applied Microscopy
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• 제40권2호
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• pp.73-80
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• 2010

Liver regeneration is a result of highly coordinated proliferation of hepatocytes and nonparenchymal liver cells. Partial hepatectomy (PH) is the most often used stimulus to study liver regeneration because, compared with other methods that use hepatic toxins, it is not associated with the tissue injury and inflammation, and the initiation of the regenerative stimulus is precisely defined. Granulocyte macrophage-colony stimulating factor (GM-CSF), which is a cytokine able to regulate the proliferation and differentiation of epithelial cells, was first identified as the most potent mitogen for bone marrow. Particularly, rrhGM-CSF, which is highly glycosylated and sustained longer than any other types of GM-CSF in the blood circulation, was specifically produced from rice cell culture. In this experiment, effects of rrhGM-CSF administration were evaluated in the regenerating liver after 78% PH of rats. Morphological changes induced by PH were characterized by destroyed hepatocyte plate around the central vein and enlarged nuclear cytoplasmic ratio and increased hepatocytes with two nuclei. And then, proliferation of liver cells (parenchymal and nonparenchymal) and rearrangement of plates and lobules seemed to be carried out during liver regeneration. These alterations in the experimental group preceded those of the control. Since proliferating cell nuclear antigen (PCNA) is known to be a nuclear protein maximally elevated in the S phase of proliferating cells, the protein was used as a marker of liver regeneration after PH in rats. PCNA levels by western blot analysis and immunohistology were compared between the two groups. PCNA protein expression of two groups at 12 hr and 24 hr after injury showed similar pattern. The protein expression showed the peak at 3 days in both groups, however, the protein level of the experimental group was higher than that of the control. On immunohistochemical observations, the reaction product of PCNA was localized at the nuclei of proliferating cells and the positive reaction in experimental group at 3 days was clearly stronger than that in control group. The results by Western blotting and immunohistology for PCNA showed similar pattern in terms of the protein levels. In conclusion, rrhGM-CSF administration during liver regeneration after 78% PH accelerated breakdown and restoration of the hepatic plate and expression of PCNA. These results suggest that rrhGM-CSF might play an important role during liver regeneration in rats.

• Journal of the Korean Arthroscopy Society
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• 제3권2호
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• pp.85-90
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• 1999

Purpose : The purpose of this study is to evaluate the clinical and histological results of the osteoarthritic patients who had second look arthroscopy after microfracture surgery. Materials and Methods : From Oct. 1997 to Dec. 1998, 46 patients, 48 knees were treated by microfracture technique. In the 22 patients, 24 knees, 'second-look' arthroscopies and biopsies were performed at 6 months following microfracture. Three patients were men and 19 patients were women. Average age of the patients were 58 years (range, 40-75 years). The average follow up period was 12 months(7-20 months). We analysed clinical results according to the nine-point scale. Also we observed type II collagen formation with immunohistochemical staining. Results : Clinical results were excellent in 83% and good in 17%. Among the 24 knees, more than 80% areas of chondral defect were covered with regenerated cartilage in 21 knees. Histologically, the regenerated tissue appears to be a hybrid of hyaline cartilage and fibrocartilage. Regenerated cartilage contains variable amount of type II collagen with immunohistochemical staining. Conclusion : Most of the patients had significant improvement clinically. 'Second-look' showed that the chondral defect areas were covered with newly grown grayish white tissue. Microfracture in the full thickness chondral defect provides and enriched environment for cartilaginous tissue regeneration.

• Journal of the Korean Society of Food Science and Nutrition
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• 제34권5호
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• pp.605-612
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• 2005

In previous studies, we evaluated the effect of the 6 energy-tonic or blood-building prescriptions of traditional oriental medicine, and observed that Si-Wu-Tang and Bu-Zhong-Yi-Qi-Tang showed high activity in the protection of the gastrointestinal and hematopoietic organs in irradiated mice. But any of these prescriptions did not show a high activity in the activation of the immune cells. We performed this study to design an herb mixture which protects the self-renewal tissues and also promotes recovery of the immune system against radiation damage. In order to meet all the requirements, we designed a new mixture of 3 edible herbs listed in Korean Food Code. The mixture of Angelim gigas radix, Cnidium officinale rhizoma and Paeonia japonica radix was decocted with hot water, and the activities of the water extract (HIM-I) were evaluated. HIM-1 stimulated the immune cells in a much higher extent than the traditional prescriptions, and promoted dramatically the growth of bone marrow stem cells in vitro. Also, HIM-1 protected digestive and hematopoietic organs against radiation as effectively as the 2 prescriptions, Si-Wu-Tang and Bu-Zhong-Yi-Qi-Tang. On the other hand, it showed high in vitro antioxidative activity that might be considered as a mechanism of the protective effects against radiation. Although the detailed mechanisms of those effects remain to be elucidated, these results indicated that HIM-I might be a useful agent for protection and recovery of body from various risk factor as well as radiation, especially since it is a relatively nontoxic natural product.