• 대한의용생체공학회:의공학회지
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• 제17권2호
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• pp.255-262
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• 1996

Antithrombogenic surFace is one of the most important things to the artificial vascular prostheses. This problem will be solved if the surface of prosthesis is covered with endothelial cells. The attachment and the growth of endothelial cells onto vascular prosthesis are very difficult. So many studies have been concentrated on the attachement of endothelial cell. But no good performance of the in uiwo experiments has been shown until now. In this study, we used the whole extracellular matrix (ECM) excreted from fibroblasts as an underlying matrix, and the endothelial cells were seeded to obtain the long term patency of vascular graft(i.e., for the patent 8 week implanted wafts in the animal model of rat). In order to study the antithrombogenic functions of cultured endothelial cells, prostaglandin(PGF 1 a) synthesis and platelet adhesion were assayed. The concentration of PGF a of stimulated group was sisnificantly higher than that of control group(21.97 $\pm$ 3.45 vs 4.93 $\pm$0.71 pg/1000 cells). The platelet adhesion of the polyurethane sheet covered with endothelial cells was lower than that of polyurethane sheet or sheet covered with ECM(1.04$\pm$0.28, 2.87$\pm$0.77, 2.89$\pm$0.70, % radioactivities, respectively). Endothelial cells grew well on polyurethane coated with ECM, synthesized the prostacyclin and functioned well as antithrombogenic. Therefore the endothelialization onto the ECM excreted from fibroblasts may be a good method for the vfudig prosthesis.

• Journal of Chest Surgery
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• 제24권7호
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• pp.693-700
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• 1991

A rare case of the association of distal aortopulmonary septal defect, aortic origin of the right pulmonary artery, intact ventricular septum, patent ductus arteriosus and interrupted aortic isthmus in a 40-day-old infant is reported. The infant was suffered from two operations with an interval of nine days. At the first operation a 10mm polytetrafluoroethylene prosthesis was inserted instead of the interrupted aortic isthmus and ductus was ligated via the left posterolateral thoracotomy. But the patient could not be weaned from the respirator because of large amount of left-to-right shunt. So the total correction was subsequently performed after an interval of nine days. At the second operation, tunneling of the right pulmonary artery to the main pulmonary artery through the aortopulmonary septal defect was performed using the Dacron patch via a longitudinal transaortic approach and a separate autologous pericardial patch was applied to the longitudinally incised margins of the anterior wall of the ascending aorta. The second postoperative course was relatively uneventful except some respiratory distress and nutritional problems. Now he is at 6 months of age and thrives well without any symptom. Because the success of the surgical repair of this complex anomalies depends upon the accurate diagnosis and meticulous design of each step of procedure prior to operation these problems are also discussed.

• 공업화학
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• 제19권4호
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• pp.357-365
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• 2008

현재 수소에너지는 화석연료의 고갈과 환경문제를 동시에 해결할 수 있는 가능성 있는 자원으로 그 중요성은 점점 커지고 있으며 지금까지 비 화석연료로부터 수소를 생산하는 방법 중에서 관심을 받는 기술은 물 전기분해이다. 물 전기분해는 전기에너지를 이용하여 무한정한 원료인 물로부터 고순도의 수소와 산소를 생산할 수 있는 친환경적인 방법이다. 본 총설에서는 물 전기화학반응의 기본원리와 종류, 최근 국내외 기술 개발현황과 발전가능성에 대해서 기술하고자 한다.

• 산업경영시스템학회지
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• 제44권3호
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• pp.192-206
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• 2021

The pharmaceutical industry is an industry that provides medicines related to the health and life of the people. The pharmaceutical industry is a traditional regulation industry with the characteristics of R&D(Research and Development), purchasing, manufacturing, distribution and consumption under strict government management. Until now, pharmaceutical companies have continued to make efforts to maintain competitiveness through patent management, new product development, and marketing. However, industries are rapidly changing, including rising costs for developing new products and expanding generic markets. As these changes and uncertainties in the management environment increase, efforts are required to improve the competitiveness of the pharmaceutical industry from a new perspective. In this study, we intend to examine the impact of SCM(Supply Chain Management) dynamic capability of pharmaceutical companies on corporate performance through partnerships to respond to market changes and uncertainties. It was determined that the agility, visibility and flexibility that constitutes the SCM dynamic capabilities would affect the performance of pharmaceutical companies. In this study, the importance of SCM dynamic capabilities and cooperative relationships was identified through surveys by SCM managers of pharmaceutical companies. Consequently, in the pharmaceutical industry, which is a regulatory industry, we have identified that SCM dynamic capabilities and cooperative relationships with partner companies have a significant impact on corporate performance.

• 한국공간구조학회논문집
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• 제17권4호
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• pp.59-68
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• 2017

This paper aims at finding some lessons applicable to successful implementation of 'The 3D Printing R/D Project' through both examining the process of adopting overseas industrialized housing production technological knowhow by home builders during the 1970's~1980's period and thereafter until now the various efforts to adjust the technologies efficiently to the Korea's unique situation. Some meaningful lessons can be summarized as follows; I) Deep understanding of 3DP technological know-why along with its inheritance, II) Readjusting of R/D period and goals(cf. Global leader Winsun's 15 years experiment), III) Restructuring for more collaborative R/D B&E system among participating researchers IV) Fostering 3DP expert-engineers and technicians from the early stage, V) Clearing legal barriers in users' adopting 3DP methods necessary, VI) Development of appropriate building material besides concrete. Therefore, it is highly recommended that the above-mentioned 6 lessons positively accepted and applied to the Research Implementation Plan in due course, especially by KICT consortium and KAIA under the guidance of Ministry of Land, Infrastructure and Transport.

• 한국정밀공학회지
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• 제16권6호
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• pp.52-57
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• 1999

Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.

• 대한본초학회지
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• 제27권5호
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• pp.45-53
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• 2012

Objectives : In recent years, the Chinese Government has been providing full support aimed at promoting the excellence of Chinese culture, including Traditional Chinese Medicine (TCM), to the world after recognizing Chinese culture and medicine as elements that can generate national wealth. Methods : In investigating China's awareness of the issues surrounding the intellectual property rights of TCM, as well as its implementation of protective measures, this study analyzed the law and platform policies of the Chinese Government, as well as the designation status of China's intangible cultural heritages and the recent research trend in the TCM field. Results : First, China is taking various protective measures based on laws and institutional devices, including the Patent Act. Second, China is protecting the intellectual property rights of traditional Chinese medicines by registering them as Chinese intangible cultural heritages or UNESCO world heritages. Third, China is seeking to promote TCM throughout the wider world through various research and academic conferences, and by strengthening ties between nations. Conclusions : With the adoption of the international regimes of the WIPO and CBD, and particularly the Nagoya Protocol in 2010, China is seeking to implement measures aimed at maximizing the national interest based on the intellectual property rights of TCM. China began to implement a system of protection of medicinal resources and the related traditional knowledge after recognizing the potential crisis that could occur if Chinese medicine-related patents were taken over by foreign countries. As such, the system now takes various forms.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권5호
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• pp.281-285
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• 2023

Background: Dentists bend needles prior to certain injections; however, there are concerns regarding needle fracture, lumen occlusion, and sharps handling. A previous study found that a 30-gauge needle fractures after four to nine 90° bends. This fatigue life study evaluated how many 90° bends a 30-gauge dental needle will sustain before fracture when bent using a needle guide. Methods: Two operators at Element Materials Technology, an independent testing, inspection, and certification company tested 48 30-gauge needles. After applying the needle guide, the operators bent the needle to a 90° angle and expressed the anesthetic from the tip. The needle was then bent back to a 0° angle, and the functionality was tested again. This process was repeated until the anesthetic failed to pass through the end of the needle due to fracture or obstruction. Each operator tested 24 needles (12 needles from each lot), and the number of sustained bends before the needle fracture was recorded. Results: The average number of sustained bends before needle failure was 40.33 (95% confidence interval = 37.41-43.26), with a minimum of 20, median of 40, and a maximum of 54. In each trial, the lumen remained patent until the needle fractured. The difference between the operators was statistically significant (P < 0.001). No significant differences in performance between needle lots were observed (P = 0.504). Conclusion: Our results suggest that using a needle guide increases the number of sustained bends before needle fracture (P < 0.000001) than those reported in previous studies. Future studies should further evaluate the use of needle guides with other needle types across a variety of operators. Furthermore, additional opportunities lie in exploring workplace safety considerations and clinical applications of anesthetic delivery using a bent needle.

• Journal of Chest Surgery
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• 제36권2호
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• pp.63-72
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• 2003

최근 증가 추세에 있는 동맥 경화성 혈관 질환에 대한 가장 중요한 외과적 치료 도구로서 생체 적합성이 우수한 인조 혈관의 필요성이 더욱 강조되고 있는 실정이다. 새로운 항혈전성 중합체 혈액 접촉 표면으로서 폴리비닐알코올-폴리우레탄 융합체와 폴리우레탄-흑연 융합체를 개발하여 실험견의 대퇴동맥에 장단기 삽입 실험을 시행함으로써 그 혈액 적합성 및 조직 적합성을 분석, 연구하는데 본 연구의 목적이 있다. 대상 및 방법 : 폴리비닐알코올-폴리우레탄 융합체로 제작된 소구경 인조 혈관 및 폴리우레탄-흑연 융합체로 제작된 봉합편과 폴리우레탄만으로 제작된 소구경 인조 혈관 및 봉합편을 6마리의 실험견에 삽입 실험(1, 2, 4, 6, 8, 16주)을 시행하였고, 4마리의 실험견에 폴리우레탄-흑연 융합체 봉합편 및 폴리우레탄 봉합편 삽입실험(1, 2, 4, 6주)을 시행하여 혈액 적합성 및 조직 적합성을 비교, 분석하였다. 결과 : 폴리비닐알코올-폴리우레탄 융합체 인조 혈관 및 폴리우레탄 인조 혈관 삽입 실험에서 1, 4, 6, 8주 실험견에서는 실험군 및 대조군 모두에서 개방성이 관찰되지 않고 혈전으로 폐쇄되어 있었고, 2주 실험견에서는 모두 개방성이 관찰되었다. 그러나 16주 실험견에서는 폴리비닐알코올-폴리우레탄 융합체 인조 혈관만이 개방성을 유지하고 있는 것이 관찰되었는데 혈액 접촉 표면은 혈전 부착이 거의 없는 깨끗한 상태를 유지하고 있었고 병리 조직 검사에서 인조 혈관의 유공성 사이로 주위 조직의 침투가 관찰되었다. 반면 폴리우레탄 인조 혈관에서는 문합부를 중심으로 혈전 형성으로 인한 폐쇄가 관찰되었다. 폴리우레탄-흑연 융합체 봉합편 및 폴리우레탄 봉합편 삽입 실험에서 2주 실험견을 제외하고는 실험군 및 대조군 모두에서 개방성을 유지하고 있는 것이 관찰되었다. 개방성을 유지하였던 봉합편에서는 봉합편 내면 위로 혈전 형성은 관찰되지 않았으며 4, 6주 실험견에서는 봉합편 내면 위로 신내막이 형성되어 있는 것이 관찰되었다. 주사형 전자 현미경 관찰 결과 폴리우레탄-흑연 봉합편의 경우 1주 실험견에서는 봉합편 내면에 섬유소가 피복되어 있었으며 간헐적으로 세포가 혼합되어 있는 것이 관찰되었다. 이와 대조적으로 4주 실험견에서는 뚜렷한 초기 형태의 내피세포가 섬유소층을 덮어서 자라고 있는 것이 관찰되었다. 이 시기에 관찰한 내피세포의 확대 사진에는 내피세포의 활성을 나타내는 미세융모가 잘 관찰되었다. 그리고 6주 실험견에서는 내피세포가 보다 성숙하여 내피세포간 단층으로 밀접한 연결을 이루면서 상대적으로 납작한 모양을 보여 마치 자갈 모양의 전형적 형태를 취하고 있었다. 폴리우레탄 봉합편의 경우 전체적으로는 폴리우레탄-흑연 봉합편과 유사한 소견을 보였지만 4, 6주 실험견에서 상대적으로 내피세포 피복 정도가 적은 것이 관찰되었다. 그러나 전자 현미경 분석의 제한상 두 군간에 내피세포 피복 정도를 정량화하기는 어려웠다. 이상의 결과로 폴리비닐알코올-폴리우레탄 융합체와 폴리우레탄-흑연 융합체는 대조군인 폴리우레탄 인조 혈관 및 봉합편에 비해 일부 우수한 양상을 보였지만 본 실험의 범위내에서는 통계적 정량적 차이를 제시할 수는 없었다. 향후 보다 광범위한 동물 실험이 필요할 것으로 사료된다.

• Journal of Chest Surgery
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• 제38권8호
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• pp.583-588
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• 2005

선천성 기관 협착증은 드문 질환이며, 장분절성 기관 협착은 아주 치명적이다. 신생아나 영아에서 심한 호흡 부전이 발생하고 복합 심기형이 동반되면 수술 교정이 쉽지 않다. 선천성 심기형을 동반한 장분절성 기관 협착으로 인공 호흡기 이탈이 불가능한 2.6 kg 체중의 어린 영아 1예와 신생아 1예에 서 기관성형술을 시행하였다. 심실중격결손증 수술 후 미만성 기관 협착이 발견된 어린 영아는 기관 절제술 및 좌측 주 기관지로의 확장 문합술을 시행받았으며, 미만성 근위부 기관 협착과 팔로사징을 동반한 신생아는 활주 기관성형술과 팔로사징 완전 교정술을 동시에 시행받았다. 두 환아 모두 술후 컴퓨터 단층 촬영에서 양호한 결과를 보였으며, 현재 증상 없이 건강한 상태이다.