물집유사천포창에 동반된 과다호산구증가증으로 발생한 뇌경색

양욱진,정한길,이승훈 대한신경과학회 2017 대한신경과학회지 Vol.35 No.3

Bullous pemphigoid (BP) is an autoimmune skin disease, which manifests as subepidermal blisters with severe itching. BP has been reported to be associated with a higher prevalence of cerebrovascular diseases in population-based studies. However, the mechanism of cerebral infarction from BP has not been elucidated yet. We hereby suggest that the missing link between BP and cerebral infarction may be eosinophil, through a case of a woman with multifocal embolic infarction.

탄성 구조물의 안정성을 고려한 형상최적설계

양욱진,최주호,Yang, Wook-Jin,Choi, Joo-Ho 한국전산구조공학회 2007 한국전산구조공학회논문집 Vol.20 No.1

본 연구에서는 설계민감도 해석기법을 사용하여 구조물의 안정성, 즉 좌굴을 고려한 형상 최적설계를 수행하였다. 형상 변수를 고려한 설계민감도 해석을 수행하기 위해 전미분 개념을 도입하고, 이를 이용하여 연속체기반의 변분방정식을 미분하여 민감도공식을 유도하였다. 기존의 유한차분법과 비교할 때 설계민감도 해석법의 장점은 설계변수의 갯수에 상관없이 매우 적은 해석횟수를 가지고도 민감도를 더 정확하게 계산할 수 있으며, 해석결과만을 이용하여 민감도계산을 수행하므로 상용 해석 소프트웨어를 활용할 수 있다는 것이다. 한편 좌굴문제를 다룰 때는 일반적으로 보나 쉘 같은 구조요소를 이용하지만 본 연구에서는 솔리드 요소를 이용한 연속체 모델로 고려하였는데 그 이유는 연속체 모델을 이용하면 뚱뚱한 형상뿐만 아니라 보나 쉘 같은 슬림(slim) 한 모델을 모두 해석할 수 있기 때문이다 설계민감도를 활용하여 여러 가지 좌굴문제에 대해 형상 설계민감도 계산 및 최적설계를 수행하였다. 그 결과 실행함수가 매우 빠르게 수렴하는 것을 확인할 수 있었고, 설계변수가 많아지고 해석시간이 길어질수록 더 효율적인 것을 알 수 있었다. This paper addresses a method for shape optimization of a continuous elastic body considering stability, i.e., buckling behavior. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Unlike the conventional finite difference method (FDM), this method is efficient in that only a couple of analyses are required regardless of the number of design parameters. Commercial software such as ANSYS can be employed since the method requires only the result of the analysis in computation of the sensitivity. Though the buckling problem is more efficiently solved by structural elements such as a beam and shell, elastic solids have been chosen for the buckling analysis because solid elements can generally be used for any kind of structure whether it is thick or thin. Sensitivity is then computed by using the mathematical package MATLAB with the initial stress and buckling analysis of ANSYS. Several problems we chosen in order to illustrate the efficiency of the presented method. They are applied to the shape optimization problems to minimize weight under allowed critical loads and to maximize critical loads under same volume.

Transcription Factors Sp1 and Sp3 Regulate Expression of Human ABCG2 Gene and Chemoresistance Phenotype

양욱진,김형표,송민지,박은영,이종주,박주홍,박근희,박종훈 한국분자세포생물학회 2013 Molecules and cells Vol.36 No.4

ABCG2 is a member of the ATP binding cassette (ABC) transmembrane proteins that plays an important role in stem cell biology and drug resistance of cancer cells. In this study, we investigated how expression of human ABCG2 gene is regulated in lung cancer A549 cells. Bind-ing of Sp1 and Sp3 transcription factors to the ABCG2 promoter in vitro and in vivo was elucidated by electro-phoretic mobility shift assay and chromatin immunoprecipitation assay. The ABCG2 promoter activity was impaired when Sp1 sites were mutated but was enhanced by overexpression of Sp1 or Sp3 proteins. Knockdown of Sp1 or Sp3 expression by short interfering RNA significantly decreased the expression of ABCG2 mRNA and protein, resulting in attenuated formation of the side population in A549 cells. In addition, Sp1 inhibition in vivo by mithramycin A suppressed the percentage of the side population fraction and sphere forming activities of A549 cells. Moreover, inhibiting Sp1- or Sp3-dependent ABCG2 expression caused chemosensitization to the anticancer drug cisplatin. Collectively, our results demonstrate that Sp1 and Sp3 transcription factors are the primary determinants for activating basal transcription of the ABCG2 gene and play an important role in maintaining the side population phenotype of lung cancer cells.

Effects of Gamma-Glutamyl Transferase on Stroke Occurrence Mediated by Atrial Fibrillation

양욱진,강동완,이승훈 대한신경과학회 2020 Journal of Clinical Neurology Vol.16 No.1

Background and Purpose Gamma-glutamyl transferase (GGT) is reported to be associated with stroke independently of the conventional risk factors. However, the underlying mechanism remains to be identified. This study focused on atrial fibrillation (AF), which also reportedly has a close association with GGT. Methods Acute ischemic stroke patients who were admitted to the Seoul National University Hospital within 7 days of stroke onset were analyzed. Multinomial logistic regression was performed to assess the relationship between GGT and cardioembolic stroke. Mediation analysis based on binary logistic regression was used to determine whether AF mediates the relationship between GGT and cardioembolic stroke. Results AF was found in 132 (15.0%) of 880 eligible patients with acute ischemic stroke, and 270 (30.7%) patients were categorized as cardioembolic stroke. High GGT levels in acute ischemic stroke patients was associated with cardioembolic stroke [odds ratio (OR)=3.42, 95% CI=1.59–7.37], but not with large-artery atherosclerosis stroke (OR=1.10, 95% CI=0.54–2.23). Approximately half (53.9%) of the total effect of GGT levels on cardioembolic stroke was mediated by AF. Conclusions The GGT level was significantly associated with cardioembolic stroke via AF. The results obtained in the present study may explain why GGT is associated with stroke.

The Clinical Benefit and Care Burden of Extending the Window of Endovascular Thrombectomy for Stroke in the Emergency Room

양욱진,강동완,국형석,하수영,이승훈 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.2

Background and Purpose The recent successes of the DAWN and DEFUSE 3 trials have extended the therapeutic time window for endovascular treatment (EVT). Accordingly, an increased care burden and clinical benefit for patients with acute stroke in the emergency room are expected. It is necessary to evaluate and respond to these changes in order to provide the best care to patients. Methods Data of patients with acute stroke or transient ischemic attack treated at Seoul National University Hospital between October 2010 and September 2016 were reviewed. To estimate the increased workload associated with the revised guidelines, clinical candidates of acute stroke based on the initial history and examination findings and eligible patients for early stroke intervention were selected. Additionally, the data of eligible patients who received EVT more than 6 hours after the onset were reviewed. Results The serial addition of intravenous thrombolysis, EVT within 6 hours, and EVT beyond 6 hours to the guidelines resulted in 506 (19.8%), 588 (23.0%), and 718 (28.0%) clinical candidates, respectively, and 329 (12.8%), 365 (14.3%), and 389 (15.2%) eligible patients out of 2,561 patients with stroke. Compared to applying the previous stroke guidelines, the number of clinical candidates increased by 130 (22.1%), whereas the number of eligible patients for early stroke intervention increased by only 24 (6.6%). Seven of the 24 eligible patients received off-label EVT and showed significantly improved neurological outcomes at discharge. Conclusions Notwithstanding the small number of subjects in this study, providing EVT to eligible patients beyond 6 hours may improve their neurological outcomes.

다낭난소증후군이 동반된 특발두개내압상승

김항래,양욱진,정한길,고상배 대한신경과학회 2015 대한신경과학회지 Vol.33 No.3

탄성 구조물의 안정성을 고려한 형상최적설계

최주호(Joo-Ho Choi),양욱진(Wook-Jin Yang) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

This paper addresses a method for shape design sensitivity analysis of a buckling load in a continuous elastic body. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Though the buckling problem is more efficiently solved by structural elements such as a beam and shell, elastic solids have been chosen for the buckling analysis in this paper because solid elements can generally be used for any kind of structure whether it is thick or thin. Sensitivity is then computed by using the mathematical package MATLAB with the initial stress and buckling analysis of ANSYS. Several problems are chosen in order to illustrate the efficiency of the presented method. They are applied to the shape optimization problems to minimize weight under allowed critical loads.

고속 안정성을 고려한 쇽업소버 최적 설계

이광기(K. K. Lee),모종운(J. W. Mo),양욱진(W. J. Yang) 한국자동차공학회 1998 한국 자동차공학회논문집 Vol.6 No.4