처음엔 당당하고 끝은 평화로웠다

김택근 신학비평사 2008 신학비평 Vol.- No.28

Ig-like domain 6 of VCAM-1 is a potential therapeutic target in TNFα-induced angiogenesis

김택근,박창식,나희준,이강승,윤애린,정준호,이석묵 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Tumor necrosis factor alpha (TNFα)-induced angiogenesis plays important roles in the progression of various diseases, including cancer, wet age-related macular degeneration, and rheumatoid arthritis. However, the relevance and role of vascular cell adhesion molecule-1 (VCAM-1) in angiogenesis have not yet been clearly elucidated. In this study, VCAM-1 knockdown shows VCAM-1 involvement in TNFα-induced angiogenesis. Through competitive blocking experiments with VCAM-1 Ig-like domain 6 (VCAM-1-D6) protein, we identified VCAM-1-D6 as a key domain regulating TNFα-induced vascular tube formation. We demonstrated that a monoclonal antibody specific to VCAM-1-D6 suppressed TNFα-induced endothelial cell migration and tube formation and TNFα-induced vessel sprouting in rat aortas. We also found that the antibody insignificantly affected endothelial cell viability, morphology and activation. Finally, the antibody specifically blocked VCAM-1-mediated cell–cell contacts by directly inhibiting VCAM-1-D6-mediated interaction between VCAM-1 molecules. These findings suggest that VCAM-1-D6 may be a potential novel therapeutic target in TNFα-induced angiogenesis and that antibody-based modulation of VCAM-1-D6 may be an effective strategy to suppress TNFα-induced angiogenesis.

Method of predicting radiator temperature distributions for thermal fatigue analysis

김택근,이상민,배성민 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

The purpose of this study was to develop an accurate method of predicting radiator surface temperatures for fatigue life estimation due to thermal loading. Two methods are currently used for this purpose. The first method involves fabricating a prototype, mounting it on a thermal load fatigue tester, imaging the surface temperature of the heat exchanger using an infrared camera, and mapping it to a Finiteelement analysis (FEA) model. The second method involves mapping the surface temperature of the heat exchanger considering the louver fins by performing computational fluid dynamics analysis using an FEA model. However, both of these methods yield poor predictions of the heat exchanger surface temperature, so the accuracy and usefulness of these techniques for fatigue life estimation are low. In this study, an effective method of predicting fatigue lives due to thermal loading was developed in a virtual laboratory environment. A complete unsteady analysis of one thermal load cycle was performed, and the simulation results agreed closely with the experimental results. The louver fin on the air side of the heat exchanger was assumed to be a porous medium in local thermal non-equilibrium. A modified Darcy equation was utilized as the momentum equation of the porous medium together with the permeability and Ergun constant for the louver fin that were obtained in a previous study. Since the permeability, Ergun constant, and interfacial heat transfer coefficient for the louver fin are given as a functions of the louver fin parameters, no additional experiments or corrections are required when the fin parameters are changed. Therefore, an efficient and accurate numerical method of determining automobile radiator temperature distributions for fatigue life prediction without requiring a prototype model was developed.

FEM으로 구현한 Cliquet Option의 가격 결정

김택근 한국재무학회 2006 한국재무학회 학술대회 Vol.2006 No.10

수송용기계기구제조업 안전관리 개선 사례

김택근,Kim, Taek-Geun 대한산업안전협회 2006 안전기술 Vol.101 No.-

The Effect of Manager Leadership on Learning Agility and Organizational Effectiveness

김택근,김문준 충북대학교 국가미래기술경영연구소 2023 기술경영 Vol.8 No.2

This study confirmed the mediating effect of learning agility between manager's leadership and organizational effectiveness as well as the effect of manager's leadership perceived by organizational members on learning agility and organizational effectiveness. In order to verify the hypotheses of the research model set up to achieve the purpose of this study, the empirical analysis of the survey results of 322 people working for companies located in the Chungcheongnam-do area is as follows. First, the manager's leadership showed a positive (+) effect on learning agility, so Hypothesis 1 was adopted. In other words, transformational leadership, sharing leadership, authenticity leadership, and coaching leadership, which are the leadership of managers, all showed significant learning agility. Second, the leadership of two hypotheses had a positive effect on organizational effectiveness. In other words, Hypothesis 2 was adopted as all sub-factors of managers' leadership had a positive effect on organizational effectiveness. Third, learning agility was statistically significantly analyzed in organizational effectiveness, and hypothesis 3 was adopted. Fourth, hypothesis 4, learning agility, was adopted as it showed a mediating effect between manager's leadership and organizational effectiveness.The main implication of this study is that the factors that affect organizational effectiveness were empirically analyzed by applying the variables of manager's leadership and learning agility.In addition, the usefulness of the manager's leadership, which is a motivating factor for organizational members to demonstrate dynamic capabilities in response to environmental changes, was confirmed. In addition, research to improve organizational effectiveness through empirical analysis of the learning agility of organizational members, who are the subject of execution, is considered to be of substantial help in improving organizational productivity and advancing sustainable management.

Development of friction model for offset strip fin with separated viscous and inertial resistances

김택근 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.12

To predict the flow resistance of a compact heat exchanger with an offset strip fin, a large number of correlations have been developed and these correlations have been well used in the engineering field. Recently, three-dimensional computational analysis has been frequently used for the design and verification of heat exchangers. To improve the accuracy of three-dimensional numerical analysis and reduce the resources used for the analysis, the fins of compact heat exchangers are assumed to be a porous medium generally. To predict the flow resistance of an offset strip fin assumed to be a porous medium, the resistance must be separated into viscous and inertial resistances. However, the correlations developed so far for the offset strip fin have not been able to distinguish between these resistance types. In this paper, we propose a new friction model that can represent the flow resistance of an offset strip fin as the sum of the viscous and inertial resistances. The new friction correlation model has a maximum error of 10 % compared to existing correlation models. In addition, using the new friction model, the permeability and the Ergun constant for offset strip fins are defined as functions of offset strip fin parameters. Therefore, when predicting the flow resistance of a compact heat exchanger with an offset strip fin using three-dimensional numerical analysis, viscous and inertial resistances can be defined without additional calculations or tests for a porous medium approach.

Three-dimensional estimation of thermal and pressure drop performance of louvered-fin tube heat exchanger using porous medium approach considering inertia effect

김택근 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

This study is purposed to estimate the pressure drop and thermal performance of three-dimensional heat exchanger units by the porous approximation, considering inertia effects. The full three-dimensional (3D) estimation of the thermal performance of the heat exchanger is very difficult because of the great complexity of the louvered-fin shape and lack of numerical resources. The volume grid used for this study was less than 10 million computational units. In order to verify the interpretation results, a compact heat exchanger having 9500 louver fins and 3D header tanks was tested experimentally and numerically. The simulation results for the air-side pressure drop agree well with the experimental result within 10 %, while the thermal effectiveness of the air was within 9.5 % of the experimental results. The present numerical method can be an effective tool to estimate the performance of multi-louver finned heat exchangers by using limited numerical resources.

원인불명의 자발성 지주막하출혈의 CT 소견

김택근 대한영상의학회 1994 대한영상의학회지 Vol.30 No.3

목 적: 원인불명의 자발성 지주막하 출혈(spontaneous subarachnoid hemorrhage of unknown cause)은 동맥류성 지주막하 출혈(aneurysmal subarachnoid hemorrhage)과 달리 합병증이 없이 매우 좋은 임상경과와 예후를 보이는 비교적 드문 질환으로, 출혈분포가 주로 중뇌주위조에 국한되는 것으로 알려져 있다. 이에대한 국내 문헌상 보고가 없어 저자들이 경험한 원인불명의 자주성 지주막하 출혈 환자의 CT소견을 분석하였다. 대상 및 방법: 지주막하 출혈의 증상으로 내원하여 증상발생 48시간 내에 CT검사를 받은 후 지주막하출혈로 확인된 환자 406명중 최초 혈관조영검사와 반복 혈관조영검사에서 동맥류가 발견되지 않은 9명과 최초 혈관조영검사상 동맥류가 없었고 또한 원인 불명의 자주성 지주막하출혈의 임상경과를 밟는 2명등 총 11명을 대상으로 조영전 CT사진에서 출혈분포를 분석 하였다. 결 과: 원인불명의 자발성 지주막하출혈 환자 11명중 전례에서 주로 중뇌주위조 출혈이 있었고 이중 5예(45%)에서는 중뇌주위에만 국한된 출혈을 보였는데, 이중 전교조, 각간조, 안상조에 출혈이 있는 경우가 각각 4예 있었고, 실비우스 열구의 기저부에 출혈이 있는 경우가 3예 있었으며, 주위조에 2예 그리고 외측 실비우스의 부분충만과 사구체조에 파급된 경우가 각각 1예 있었다. 나머지 6예에서는 출혈분포가 중뇌주위조 이상으로 파급되었는데, 뇌실출혈 3에(27%), 피질구(cortical sulci) 2예, 그리고 외측 실비우스 열구가 완전히 충만된 경우가 5예에서 보였다. 결 과: 원인불명의 자발성 지주막하 출혈을 진단함에 있어서 과거에는 중뇌주위조에만 국한된 출혈을 보이는 CT소견이 중요하다고 알려져 있었으나, 본 연구 결과 정상 뇌혈관 조영검사와 합병증을 남기지 않는 좋은 임상적 경과가 CT상 조 출혈 분포보다 더 중요할 것으로 사료된다. Purpose: Spontaneous subarachnoid hemorrhage(S-SAH) is a relatively rare disease with good clinical course and prognosis. The purpose of this study is to evaluate the cisternal blood distribution on CT in patient with S-SAH.Materials and Methods: Out of 406 patients with subarachnoid hemorrhage on brain CT scan, 11 patients confirmed to be S-SAH by angiography and clinical follow-up were examined. We analysed the CT findings of these 11 cases retrospectively.Results: Five patients had only perimesencephalic distribution of hemorrhage: the prepontine, the interped-uncular, and the suprasellar cisterns were involved in 4 cases each, the basal sylvian cistern in 3 cases, and the ambient cistern in 2 cases. The quadrigeminal and a portion of the lateral sylvians were also involved in 1 case each. Six patients revealed cisternal hemorrhage extending beyond the perimesencephalic cistern into the ventricles, cortical sulci, and lateral sylvian fissure. intraventricular hemorrhage was noted in 3 cases of these6 patients.Conclusion ; Our study suggests that uncomplicated clinical course and normal angiographic finding are more important than CT distribution of cisternal hemorrhage in diagnosing S-SAH.

제 4 뇌실 종양의 CT 및 MRI 소견

김택근 대한영상의학회 1994 대한영상의학회지 Vol.31 No.4