• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.1-1
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• 2011

We developed a new generalized synthetic procedure, called as "heat-up process," to produce uniform-sized nanocrystals of many transition metals and oxides without a size selection process. We were able to synthesize uniform magnetite nanocrystals as much as 1 kilogram-scale from the thermolysis of Fe-oleate complex. Clever combination of different nanoscale materials will lead to the development of multifunctional nano-biomedical platforms for simultaneous targeted delivery, fast diagnosis, and efficient therapy. In this presentation, I would like to present some of our group's recent results on the designed fabrication of multifunctional nanostructured materials based on uniform-sized magnetite nanoparticles and their medical applications. Uniform ultrasmall iron oxide nanoparticles of <3 nm were synthesized by thermal decomposition of iron-oleate complex in the presence of oleyl alcohol. These ultrasmall iron oxide nanoparticles exhibited good T1 contrast effect. In in vivo T1 weighted blood pool magnetic resonance imaging (MRI), iron oxide nanoparticles showed longer circulation time than commercial gadolinium complex, enabling high resolution imaging. We used 80 nm-sized ferrimagnetic iron oxide nanocrystals for T2 MRI contrast agent for tracking transplanted pancreatic islet cells and single-cell MR imaging. We reported on the fabrication of monodisperse magnetite nanoparticles immobilized with uniform pore-sized mesoporous silica spheres for simultaneous MRI, fluorescence imaging, and drug delivery. We synthesized hollow magnetite nanocapsules and used them for both the MRI contrast agent and magnetic guided drug delivery vehicle.

• 한국버섯학회지
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• 제22권1호
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• pp.1-7
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• 2024

Mushrooms play crucial roles as reservoirs of naturally occurring bioactive compounds. Among these, Cordyceps militaris is significant because of its well-established reputation for organoleptic excellence and positive health effects, which have led to its widespread commercialization. In contrast, the key properties of Paecilomyces variotii, an ectomycorrhizal symbiont, has received limited attention. In alignment with current research trends, the study of the mycelia and culture media of these mushrooms hold promise in identifying potential sources of valuable bioactive compounds. In the present study, we investigated C. militaris and P. variotii for their phenolic acids and sterols, assessing antioxidant capacity, anti-inflammatory effects, and anti-proliferative activity. Interestingly, P. variotii mycelia exhibited higher concentrations of ergosterol and phenolic compounds, with comparable levels observed in the fruiting bodies, along with superior antioxidant activity compared to that of C. militaris. In contrast, C. militaris mycelia demonstrated anti-inflammatory effects (which were absent in P. variotii mycelia) and cytotoxicity comparable to, and at times exceeding, that of its fruiting bodies (in contrast to P. variotii). In addition, the species analyzed in this study displayed variations in growth rates and mycelial production, which merit consideration for potential future applications and further study.

• 복식문화연구
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• 제16권6호
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• pp.992-1007
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• 2008

This study was meant to offer the data for predicting the product plan answering the diverse demands for consumers based on the results of analyzing the image and formative property by transforming the stripe patterns. The concrete study way is composed of the collected stimulus centering on the interval of the stripe pattern and value contrast coloration. Consequently 192 stimuli, changed by the pattern direction and pattern interval, clothing style, and contrast coloration, are selected. The experimental materials made for this study are a set of stimuli and response scale. The statistics way used in analysis was factor analysis, ANOVA, dispersion analysis, multiple classification analysis. The results of this study were summed as following. Firstly, In the value contrast, a pair of 27 adjectives were made of attractiveness, activeness, gracefulness, visibility, and tenderness dimension. Secondly, the direction of the pattern, interval, clothing style, and contrast coloration were respectively transformed according to value contrast.

• 한국광물학회지
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• 제28권2호
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• pp.165-171
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• 2015

부산과 울산의 중심지역에 대해 공기 중의 분진시료를 채취하여, 위상차현미경, 위상차분산현미경, 주사전자현미경 등으로 석면을 분석한 결과, 석면은 검출한계 이하로서 확인되지 않았다. 공기중의 분진시료에는 섬유상물질이 다수 포함되었으나, 이들은 대부분 유기질 섬유인 것으로 나타났다. 무기질 섬유물질로는 암면, 세라믹섬유, 석고 등이 소량 포함되었으며, 비섬유상인 석영, 방해석, 장석등의 광물도 가끔 관찰되었다. 국내의 공기 중 분진의 석면분석은 주로 위상차현미경으로 관찰하는 것으로 규정되어 있으나, 이것만으로는 석면의 식별이 불가능한 것으로 나타났다. 따라서 일본 JIS법과 같이 저온회화 처리 장치에 의한 유기물질 제거 후에 분산염색법으로 석면을 식별하고 계수하는 것이 효율적인 것으로 사료된다.

• 핵의학기술
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• 제28권1호
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• pp.23-29
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• 2024

Purpose: 99mTc-mebrofenin hepatobiliary scintigraphy (HBS) is an important and clinically useful diagnostic imaging study for detecting complications after liver transplantation. CT contrast agents due to their high atomic numbers, lead to a decrease in gamma ray count rates. This study investigated the impact of CT contrast agents on the uptake of 99mTc-mebrofenin in the liver. Materials and Methods: The quantitative HBS was performed on sixty-two liver transplantation patients (male:female=36:26), with a mean age of 59.4±6.4 years. Statistical comparison of hepatic uptake reduction ratio (HURR%) before and after the injection of CT contrast agents was performed using a paired t-test. Results: Hepatic uptake of the reduction ratio was 94.47±3.65% for the pre-CT contrast agents and 92.17±4.00% for the post-CT contrast agents. HURR% after CT contrast agent injection showed a statistically significant difference compared to before the injection (t=11.09, P<0.001). Conclusion: It will be necessary to pay attention when examining the HBS of patients with liver transplantation after the injection of CT contrast medium. It is advisable to schedule the examination on a different day to prevent residual contrast medium in the body from interfering with the quantitative evaluation of the nuclear medicine examination.

• 한국자기공명학회논문지
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• 제9권2호
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• pp.93-102
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• 2005

Purpose: To develop an advanced non-linear curve fitting (NLCF) algorithm for dynamic susceptibility contrast study of brain. Materials and Methods: The first pass effects give rise to spuriously high estimates of $K^{trans}$ in voxels with large vascular components. An explicit threshold value has been used to reject voxels. Results: By using this non-linear curve fitting algorithm, the blood perfusion and the volume estimation were accurately evaluated in T2*-weighted dynamic contrast enhanced (DCE)-MR images. From the recalculated each parameters, perfusion weighted image were outlined by using modified non-linear curve fitting algorithm. This results were improved estimation of T2*-weighted dynamic series. Conclusion: The present study demonstrated an improvement of an estimation of kinetic parameters from dynamic contrast-enhanced (DCE) T2*-weighted magnetic resonance imaging data, using contrast agents. The advanced kinetic models include the relation of volume transfer constant $K^{trans}\;(min^{-1})$ and the volume of extravascular extracellular space (EES) per unit volume of tissue $\nu_e$.

• Investigative Magnetic Resonance Imaging
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• 제24권3호
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• pp.154-161
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• 2020

Purpose: A CT angiography spot sign (CTA-spot) is a significant predictor of the early expansion of an intracerebral hemorrhage (ICH-Ex). Dynamic-susceptibility-contrast magnetic resonance imaging (DSC-MRI) can track the real-time leaking of contrast agents. It may be able to indicate active bleeding, like a CTA-spot. Materials and Methods: From September 2014 to February 2017, we did non-contrast CT, CTA, and DSC-MRI examinations of seven patients with acute ICH. We investigated the time from symptom onset to the first contrast-enhanced imaging. We evaluated the time course of the contrast leak within the ICH at the source image of the DSC-MRI and the volume change of ICH between non-contrast CT and DSC-MRI. We compared the number of slices showing CTA-spots and DSC-MRI leaks. Results: The CTA-spot and DSC-MRI leak-sign were present in four patients, and two patients among those showed ICH-Ex. The time from the symptom onset to CTA or DSC-MRI was shorter for those with a DSC-MRI leak or CTA-spot than for three patients without either (70-130 minutes vs. 135-270 minutes). The leak-sign began earlier, lasted longer, and spread to more slices in the patients with ICH-Ex than in those without ICH-Ex. The number of slices of the DSC-MRI leak and the number of the CTA-spot were well correlated. Conclusion: DSC-MRI can demonstrate the leakage of GBCA within hyperacute ICH, showing the good contrast between hematoma and contrast. The DSC-MRI leakage sign could be related to the hematoma expansion in patients with ICH.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2004년도 동계학술연구발표회 논문개요집
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• pp.115-116
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• 2004

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.92.2-92
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• 1998

• 한국재료학회지
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• 제3권4호
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• pp.388-394
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• 1993

PVC/액정 복합막의 응집상태 및 전기광학 특성을 넓은 막조성(30-70wt% LC)에 걸쳐 조사하였다. 또한 optical contrast가 가장 좋은 40/60(PVC/LC)중량조성으로 된 복합막에 대해서는 온도 및 외부교류전계의 주파수 및 전압응답을 측정한 결과 문턱 주파수는 20$V_{p-p}$ 이하(1 kHz, $25^{\circ}C$), rise time및 decay time은 모두 10ms 이하(V$100 _{p-p}$ , 1 kHz, $25^{\circ}C$)였다.