• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.5
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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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• v.46 no.2
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.513-514
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.647-648
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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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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• v.35 no.1
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• pp.27-35
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• 2002

Background: A perioperative myocardial infarction(PMI) is one of the major complications after CABG. Among diagnostic methods of PMI, CK-MB activity assays have been increasingly replaced by CK-MB mass assays, which have more sensitive, simple measurement. Also, new cardiac-specific and -sensitive marker, cardiac troponin I(cTnl), has been shown to be a marker of myocardial infarction. We report our evaluation of clinical significance of CK-MB mass and cTnl as a marker of PMI after CABG. Material and Method: We studied 32 patients who underwent CABG at Kangdong Sacred Hospital between April 2000 and April 2001. Postoperative serum CK-MB activity level, serum CK-MB mass, cTnl, electrocardiogram, echocardiogram, and clinical data were recorded prospectively The diagnosis of PMI was defined as positive 2 among 3 or all of the following , by a new Q wave on the electrocardiogram, by serum CK-MB activity higher than 200 lU/L within 72 hours after operation, and by new regional wall motion abnormality on the echocardiogram. Result: After CABG, 3 patients had sustained a PMI according to current diagnostic criteria. As serum CK-MB activity time course, a level of CK-MB activity 12 hours after CABG had very linear correlated significance with serum CK-MB mass 24hours(R=0.946) and cTnl 48 hours(R=0.933) after CABG(p=0.000). As we used a receiver operating characteristics curve(ROC curve) for a diagnostic cutoff value in patients with PMI, serum CK-MB mass levels higher than 30.05 ug/L 24 hours after CABG detected the presence of PMI with an area under the ROC curve of 1.0, a sensitivity of 100%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 100%. Also serum cTnl levels higher than 17.15 ug/L 48 hours after CABG detected the presence of PMI with an area under the ROC curve of 0.98, a sensitivity of 100%, a specificity of 96.6%, a positive preclictive value of 75%, and a negative predictive value of 100% Conclusion: We concluded that both the measurement of CK-MB mass and cTnl are the easier, accurate methods as a diagnostic marker of PMT after CABG, also as a proposal of diagnostic cutoff value enables to an early detection of PMI. However, a 1arger number of patient will be needed because of statistic limitation that a small number of participating patients, a small number of PMI.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.265-266
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• 2013

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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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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• v.25 no.3
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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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• v.7 no.4
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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.