• Journal of Internet Computing and Services
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• v.14 no.6
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• pp.107-115
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• 2013

Various networks can be observed in the world. Knowledge networks which are closely related with technology and research are especially important because these networks help us understand how knowledge is produced. Therefore, many studies regarding knowledge networks have been conducted. The assortativity coefficient represents the tendency of connections between nodes having a similar property as figures. The relevant characteristics of the assortativity coefficient help us understand how corresponding technologies have evolved in the keyword-based patent network which is considered to be a knowledge network. The relationships of keywords in a knowledge network where a node is depicted as a keyword show the structure of the technology development process. In this paper, we suggest two hypotheses basedon the previous research indicating that there exist core nodes in the keyword network and we conduct assortativity analysis to verify the hypotheses. First, the patents network based on the keyword represents disassortativity over time. Through our assortativity analysis, it is confirmed that the knowledge network shows disassortativity as the network evolves. Second, as the keyword-based patents network becomes disassortavie, clustering coefficients become lower. As the result of this hypothesis, weconfirm the clustering coefficient also becomes lower as the assortative coefficient of the network gets lower. Another interesting result concerning the second hypothesis is that, when the knowledge network is disassorativie, the tendency of decreasing of the clustering coefficient is much higher than when the network is assortative.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.4
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• pp.355-369
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• 1991

미세수술을 이용한 재건외과 분야에서 빈번히 혈관이식이 요구된다. 이러한 경우 자가정맥이 가장 널리 사용되고 있으며 그의 신뢰성도 인정되어 있다. 그러나 정맥 채취에 따르는 부가적인 수술이 요구되며 혈관 공여부에 또다른 결손을 초래한다. 동결건조동종정맥은 이러한 점을 보완하고 자가정맥을 대체할 수 있는 잠재성이 있다. 이에 동결건조동종정맥의 효율성을 알아보고자 2.5cm 길이의 가토대퇴정맥을 $-65^{\circ}C$, 200 mtorr의 음압으로 동결건조시킨 다음 대퇴동맥 결손부에 동종이식하고(n=24), 신선한 가토대퇴정맥 동종이식군(n=24)과 자가정맥이식군(n=24)을 1주 간격으로 4주간 비교 관찰하였다. 2주 개존율은 동결건조동종정맥 이식군, 100%;동종정맥이식군, 50%; 자가정맥이식군, 100%이었으며 4주 개존율은 동결건조동종정맥이식군, 83.3%;동종정맥이식군, 50%;자가정맥이식군, 100%로서 동결건조처치만으로 동종정맥이식의 생존율을 증가시켰다. 미세임파구세포독성검사에서는 동결건조정맥의 항원성이 상당히 낮아져있음을 알 수 있었다. 그러나 동결건조정맥의 내막세포화가 주사전자현미경 및 광학현미경 소견상 자가정맥보다 지연됨이 관찰되었다. 이러한 결과를 종합해 볼 때 동결건조동종정맥은 아무런 처치를 하지않은 신선 동종정맥보다 현저한 장점이 있었지만, 자가정맥이식을 대신할 수 있는 보다 더 좋은 대체방법이라는 견지에서는 임상 적용이 어려울 것으로 사료되었다.

• Journal of Chest Surgery
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• v.33 no.12
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• pp.929-934
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• 2000

배경: 기관의 동종이식편은 초냉동보관으로 생육성을 유지할 수 있으며 항원성이 줄어든다고 알려졌으나 냉동보관 온도 및 기간에 따른 항원성의 변화는 아직까지 명확히 밝혀져 있지 않다. 따라서 이번 연구에서는 냉동보관 온도의 차이 및 기간이 쥐 기관 동종이식편의 거부반응에 미치는 영향을 연구하였다. 대상 및 방법: 24개의 쥐 기관을 적출하여 12개씩 -8$0^{\circ}C$ 냉동고 및 -196$^{\circ}C$ 질소탱크에 각각 1, 3, 6개월씩 보관하였다. 냉동보관한 기관을 반으로 나누어 48마리의 쥐복강에 대망으로 감싼 다음 이식하였다. 1, 3, 5군은 -8$0^{\circ}C$ 냉동고에 각각 1, 3, 6개월씩 보관한 기관 동종이식편을 이식하였고 2, 4, 6군은 -196$^{\circ}C$ 질소탱크에 각각 1, 3, 6개월씩 보관한 기관 동종이식편을 이식하였다. 7군은 대조군으로 냉동보관하지 않은 동종이식편을 이식하였다. 이식후 14일째 이식된 동종이식편을 적출하여 간질조직의 단세포 침윤정도 및 내강 폐쇄 정도를 관찰하여 거부반응을 정도를 측정하였다. 결과: 7개 군 모두에서 중등도 이상의 심한 단세포 침윤을 보였으며 각군간의 통계학적인 차이를 보이지 않았다. 1, 2, 3, 4, 5, 6군에서 7군에서 보다 내강 폐쇄 정도가 적었으나 통계학적인 의의는 없었다. 모든 군에서 연골주위 단세포 침윤이 심한 경우에도 연골세포는 비교적 생육성을 잘 유지하고 있었다. 결론: 냉동보관 온도 및 보관 기간의 차이에 따른 동종이식편의 거부반응의 차이는 없었으며 모든 군에서 심한 거부반응을 보였다. 따라서 냉동 보관 쥐 동종이식편을 이용한 실험에서는 적절한 면역억제제의 사용이 필수적이라고 생각된다.

• Journal of Chest Surgery
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• v.30 no.8
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• pp.819-822
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• 1997

Aortic valve replacement with aortic allograft has been considered a treatment of choice for aortic valve disease secondary to bacterial endocarditis because of its good homodynamic performance and higher resistance to infection. The aortic root replacement technique might be superior to the subcoronary allograft implantation technique with regard to aortic regurgitation. A 46 yea,rs old male patient had acute aortic regurgitation with progressing heart failure secondary to acute bacterial endocarditis. The patient underwent emergent aortic root replacement using 20 mm aortic allograft. At operation, right coronary cusp perforation and heavy calcification of commissure between right and left coronary cusp were observed. The patient recovered well and postoperative echocardiography demonstrated no aortic regurgitation. Inflammatory signs were subsided after 8 weeks of antibiotics therapy. Medically uncontrolled acute bacterial endocarditis was treated successfully by aortic root replacement using aortic homograft.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1127-1133
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• 1998

Background: There are no ideal substitutes for tracheal replacement. Therefore we investigated the possibility of clinical use of cryopreserved tracheal homograft with special interest in the viability and rejection of the epithelial cell and cartilage. Material and Method: Rabbit's trachea was sected and stored in liquid nitrogen tank for 1 month. Tracheal replacement was done in 45 rabbits with autograft(n=15, Group 1), fresh allograft(n=15, Group 2) and cryopreserved homograft(n=15, Group 3). After 7, 14, and 30 days, 5 rabbits in each group were sacrificed and the regeneration of epithelium and cartilage and the degree of rejection were assessed by counting the monocellular infiltration. Result: Investigation at day 7, showed no difference in epithelial regeneration, however, at days 14 and 30, Group 1 showed better regeneration of epithelium than groups 2 and 3. There was no difference of epithelial regeneration between group 2 and 3. There was little rejection at day 7, but at days 14 and 30, there was significant rejection in group 2 and group 3.(P<0.05). Group 3 showed lesser rejection than group 2 at days 14 and 30, but it was not statistically significant. Cartilage showed no rejection and maintained its viability in groups 2 and 3. Conclusion: Cryopreserved tracheal homograft can maintain its viability, therefore it may represent a possibility of clinical application for tracheal replacement. However, cryopreservation can not eliminate the antigenicity of the trachea completely. Furthere studies for lowering the antigenicity and rejection should be performed for an ideal substitute for tracheal replacement.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.68-74
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• 2011

This papers investigated the mechanical characteristics and the weldability of identical as well as dissimilar welding by GTAW for STS 304 and STS 316L. It is applied to double wall gas pipe of duel fuel engine for LNG carrier. Consequently, the weldability of dissimilar and identical welded zone of STS 304 decreased compared to base metal significantly. The result of microstructure observation for welded zone, a degree of acicular ferrite in welding zone for STS 304 presented more than STS 316L. The hardness of welding zone for STS 304 presented higher value than that for STS 316L by this effect.

• Journal of Chest Surgery
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• v.33 no.12
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• pp.948-953
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• 2000

일반적으로 개심술에는 많은 양의 실현이 따르게 마련이고 그 결과로 많은 수혈을 하게 되는데, 응혈 이상증, 과민반응, 급성호흡곤란증 등의 수혈부작용과 간염 및 후천성면역결핍증 등의 질병 감염의 위험성, 그리고 종교적인 이유 등으로 최근들어 동종수혈을 줄이고자 하는 노력이 계속되고 있다. 개심술시 동종수혈에 따른 부작용을 피하기 위해, 동종수혈 없이 자가수혈만으로도 성인개심술이 가능한지 연구하였다. 서울대학교 의과대학 흉부외과학 교실에서는 1996년 1월부터 12월까지 1년 간 자가수혈만으로 개심술을 시행한 실험군 126명과 동종수혈을 시행한 대조군 45명을 대상으로 양군을 비교하였다. 양군 간에 환자의 성별, 대동맥 질환을 제외한 기타 질환, 대동맥수술과정을 제외한 단순 및 복잡수술과정, 평균 대동맥 겸자시간, 수술전 및 수술후 1일째와 7일째 혈색소수치 및 적혈구용적, 수술 전후의 protein 수치와 수술후 albumin 수치, 자가수혈량과 혈장증량제 사용량 등에서는 유의한 차이가 없었으나, 연령, 대동맥질환 및 대동맥수술과정, 평균체외순환시간, 수술 후 회수된 피의 양, 수술직후의 혈색소수치와 적혈구용적, 수술 전 albumin 수치, 그리고 3일간 흉관으로 배액된 양에 있어 차이가 있었다. 본 연구를 통해 동종수혈 없이 자가수혈만으로도 큰 차이없이 여러 종류의 성인 개심술을 성공적으로 할 수 있음을 보고한다.

• Journal of Sasang Constitutional Medicine
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• v.8 no.2
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• pp.165-190
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• 1996

Homoeopathy was established in 1796 by German physician Samuel Hahnemann(1755~1843). This method is an alternative form of therapy involving treatment by natural remedies. The basic principles of homeopathic medicine, "Similia similibus curantur", "experimenta in hominesano", "doses minimae" and "unitas remedii", are founded upon the idea of illness as a disorder of the internal equilibrium at the physical, mental and psychic levels. The three distinguishing characteristics of homeopathy are that remedies are prescribed on the totality of a person's symptoms, that the remedy likely to cure a person is a dilution of that remedies are prepared using microdoses of substances which are diluted and then vigorously shaken. This paper describes the basic principled of homeopathy and compared with the Sa-sang constitutional Medicine from the literature. 1. Homeopathy is the holistic medicine that derived from the competition of vitalism and mechanism, and it is the one of natural medicine that absorbed the influence of asian scholarship and theoretical background of oriental medicine. 2. Homeopathic remedy typologies and Sa-sang constitutional Medicine are same in the mind-body correlativity and in-born typologies. 3. In homeopathy, constitutional types are distinguished the variable types with variety of symptoms by the remedy picture, but comparably in Sa-sang constitutional medicine, it is determined only by the constitutional symptoms.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.553-558
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• 1997

Arterial allografts have known advantages over prosthetic vascular conduit for treatment of heart valvular disease, congenital heart disease and aortic disease. Cell viability may play a role in determining the longterm outcome of allografts. Endothelial cell is one important part in determining the allograft viability. To evaluate the viability of endothelial cells using current allograft preservation technique, porcine heart valve leaflets and arterial wall were subjected to collagenase digestion. Single endothelial cell suspension was labeled with GSA-PITC(Griffonia simplicifolia agglutininfluorescein isothiocyan te), a vascular, endothelial cell specific marker. The cell suspension was washed and incubated with Pl(Propidium iodide), which does not bind with viable cells, Endothelial cell viability was evaluated by calculating the percentage of GSA-FITC(+) and Pl(-) group using flowcytometric analysis. Allografts were treated with $4^{\circ}C$ antibiotic solo!ion for 24 hours for sterilization. After this, half of allografts were stored in $4^{\circ}C$ RPMI 1640 with HEPES buffer culture medium with 10% fetal bovine serum for 1 to 14 days(Group I). Another half of allografts were cryopreserved with a currently used technique (Group II). During the procurement and sterilization of arterial allografts, 22.8% and 24.4% of endothelial cell viability declined, respectively. In Group I, 11.9% of endothelial cell viability declined further steadily during 14 days of storage. In Group II, 13.7% of endothelial cell viability declined. These results show that largest loss of endothelial cell viability occurs during the nitial process. After 14 days of arterial allograft storage under $4^{\circ}C$ nutrient medium or cryopreservation, about 40% of endothelial cell viability is maintained. There were no differences between the endothelial cell viability from aortic valve leaflet, pulmonic valve leaflets, aortic wall and pulmonic wall.

• Journal of Veterinary Clinics
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• v.22 no.4
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• pp.322-327
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• 2005

DLA class I complement-dependent cytotoxicity (CDC) cross-match method was established to control hyperacute rejections in organ transplantation. The aim of the present study is to investigate if DLA class 1 CDC corssmatch method is effective to prevent hyperacute rejections in canine renal allografts. Seven mongrel dogs of similar age and weight were used. Erythrocyte crossmatch was first performed and only the negatives were used. Among the same blood types, CDC cross-match was performed. Anti-dog serum, Hank's balanced salt solution(HBSS), and tile self-serum was used as a positive-, a negative-, and all auto-control respectively. After the reaction with class I complement, it was stained with eosin and scored by international cytotoxicity scoring system under inverted phase microscope. According to these results, kidneys oi CDC negatives among same blood types were cross-transplanted to observe the incidence of hyperacute rejections. One of four 1.2 B blood type dogs had autoantibodies. here were negative CDC results among each blood type, and also there were negative results between different blood types. Two pairs with the same blood types and negative CDC results underwent allo-transplantation each other. There were no hyperacute rejections. DLA cross-match method studied in this experiment for canine renal allograft can be effective to prevent hyperacute rejections. it may be applicable for the future studies of histocompatibility testing in canine renal allografts.