• 한국생산제조학회지
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• 제22권5호
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• pp.831-836
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• 2013

This study demonstrates the process of fabricating patterns using tribonanolithography (TNL),with laboratory-made micro polycrystalline diamond (PCD) tools that are attached to an atomic force microscope (AFM). The various patterns are easily fabricated using mechanical scratching, under various normal loads, using the PCD tool on single crystal silicon, which is the master mold for replication in this study. Then, polydimethylsiloxane (PDMS) replica molds are fabricated using precise pattern transfer processes. The transferred patterns show high dimensional accuracy as compared with those of TNL-processed silicon micro molds. TNL can reduce the need for high cost and complicated apparatuses required for conventional lithography methods. TNL shows great potential in that it allows for the rapid fabrication of duplicated patterns through simple mechanical micromachining on brittle sample surfaces.

• Journal of Korean Neurosurgical Society
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• 제46권2호
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• pp.99-102
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• 2009

Objective: Cardiac dysfunction after aneurysmal subarachnoid hemorrhage (SAH) is associated with elevation of serum cardiac troponin I (cTnl) levels. Elevation of cTnl predicts cardiopulmonary and neurological complications, and poor outcome. Methods: We retrospectively reviewed the medical and radiologic records of 114 (male: 30, female: 84) patients who developed aneurysmal SAH between January 2006 and June 2007 and had no history of previous cardiac problems. We evaluated their electrocardiography and cTnl level, which had been measured at admission. A cTnl level above 0.5 $\mu$g/L was defined as an indicator of cardiac injury following SAH. We examined various clinical factors for their association with cTnl elevation and analyzed data using chi-square test, t-test and logistic regression test with SPSS version 12.0. The results were considered significant at p< 0.05. Results: The following parameters shows a correlation with cTnl elevation: higher Hunt-Hess (H-H) grade (p = 0.000), poor Glasgow Outcome Scale (GOS) score (p = 0.000), profound pulmonary complication (p = 0.043), higher heart rate during initial three days following SAH (p = 0.029), ruptured aneurysm on communicating segment of internal carotid artery (p = 0.025), incidence of vasospasm (p = 0.421), and duration of hyperdynamic therapy for vasospasm (p = 0.292). A significant determinants for outcome were cTnl elevation (p = 0.046) and H-H grade (p = 0.000) in a multivariate study. Conclusion: A cTnl is a good indicator for cardiopulmonary and neurologic complications and outcome following SAH. Consideration of variable clinical factors that related with cTnl elevation may be useful tactics for treatment of SAH and concomitant complications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.513-514
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.647-648
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.268-271
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• 2005

Etch resistance of mask layer on silicon substrate modified by AFM-based Tribo-Nanolithography (TNL) in Aqueous Solution in an aqueous solution was demonstrated. n consists or sequential processes, nano-scratching and wet chemical etching. The simple scratching can form a mask layer on the silicon substrate, which acting as an etching mask. For TNL, a specially designed cantilever with diamond tip, allowing the formation of mask layer on silicon substrate easily by a simple scratching process, has been applied instead of conventional silicon cantilever fur scanning. This study demonstrates how the TNL parameters can affect the etch resistance of mask layer, hence introducing a new process of AFM-based maskless nanolithography in aqueous solution.

• Journal of Chest Surgery
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• 제35권1호
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• pp.27-35
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• 2002

배경: 술후 심근경색(perioperative myocardial infarction;PMI)은 관상동맥 우회술 후 중요한 합병증 중 하나이다. PMI의 진단 방법 중 CK-MB 활성도(CK-MB activity) 측정보다 민감하고, 간단한 측정 방법을 가진 CK-MB 농도(CK-MB mass)의 측정으로 점차 대체되고 있다. 또한, cardiac troponin I(cTnl)는 심근경색의 표지자로 민감도와 특이도가 가장 높은 것으로 소개되고 있다. 본 연구는 관상동맥 우회술 후 심근경색의 표지자로서 CK-MB농도와 cTnl의 임상적 의의성에 대한 평가를 보고하고자 한다. 대상 및 방법: 2000년 4월부터 2001년 4월까지 강동성심병원에서 관상동맥 우회술을 받은 32명의 환자를 대상으로 하였다. 술후 CK-MB 활성도, CK-MB농도, cTnl, 심전도, 심초음파, 임상적 자료를 전향적으로 기록하였다. 술후 심근경색의 진단은 심전도에서 새로운 Q파 출현, CK-MB 활성도가 72시간안에 200 lU/L 이상, 심초음파에서 심근벽의 새로운 심근벽 운동이상 등의 3가지 중 2가지 이상인 경우로 정의하였다 결과: 관상동맥 우회술 후 3례에서 진단 기준에 부합된 경우였다. 시간 경과에 따라, 술후 12시간의 CK-MB활성도와 술후 24시간의 CK-MB농도(R=0.946), 술후 48시간의 cTnl(R=0.933)는 매우 상관성이 있었다(p=0.000). PM의 진단기준치를 찾기 위해 ROC(receiver operating characteristics) 곡선을 이용하였으며, PMI의 환자중 술후 24시간에서 CK-MB 농도가 30.05 ug/L보다 높은 측정값에서 PMI를 발견할 수 있었고, 이 때의 ROC 곡선의 하단 단면적은 1이었으며, 민감도 100%, 특이도 100%, 양성 예측도 100%, 음성 예측도 100% 이었다. cTnI의 경우 술후 48시간에서 17.15ug/L보다 높은 측정값에서 PMI를 발견할 수 있었고, 이 때의 ROC 곡선의 하단 단면적은 0.98이었으며, 민감도 100%, 특이도 96.6%, 양성 예측도 75%, 음성 예측도 100% 이었다. 결론: 관상동맥 우회술 후 심근경색의 진단적 표지자로서 CK-MB농도와 cTnl의 측정은 간단하고 정확한 방법으로 판단되며, 진단기준치를 제시함으로서 술후 심근경색의 조기 발견을 가능하게 할 수 있을 것이라 생각된다. 그러나 본 연구에서는 대상환자 수가 적었고, 적은 수의 환자에서 심근경색이 발생하여 통계적인 제한이 있을 수 있어 향후 더 많은 대상의 수가 필요할 것으로 사료된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.265-266
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• 2013

• 한국정밀공학회지
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• 제23권8호
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• pp.39-46
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• 2006

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin mask layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip. The mask layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the novel fabrication processes of the micro cantilever and diamond tip as a tool for TNL using micro-patterning, wet chemical etching and CVD. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.240-249
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• 2002

Dibenzyl-g-butyrolactone and 1,2,3,4-tetrahydro-2-naphthoic acid $\gamma$-lactone (TNL) derivatives were synthesized and evaluated for cytotoxic activity against some cancer cell lines. It was found that TNL derivatives with a shorter distance between C-4 in ring A and C'-2 in ring C were more cytotoxic, while dibenzyl-${\gamma}$-butyrolactones with a longer one were nearly inactive. In TNL series, presence of 3,4-dioxy group in ring A and 2-methoxy group in ring C was essential for the enhancement of the activity.

• International Journal of Precision Engineering and Manufacturing
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• 제7권4호
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• pp.8-13
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• 2006

Nanoscale fabrication of silicon substrate in an aqueous solution based on the use of atomic force microscopy was demonstrated. A specially designed cantilever with a diamond tip, allowing the formation of a mask layer on the silicon substrate by a simple scratching process (Tribo-Nanolithography, TNL), has been applied instead of the conventional silicon cantilever for scanning. A slant nanostructure can be fabricated by a process in which a thin mask layer rapidly forms on the substrate at the diamond tip-sample junction along scanning path of the tip, and simultaneously, the area uncovered with the mask layer is etched. This study demonstrates how the TNL parameters can affect the formation of the mask layer and the shape of 3-D structure, hence introducing a new process of AFM-based nanolithography in aqueous solution.