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Search Results: 1 - 10 of 14756 matches for " Ju-Won Park "
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Nanotechnology for Early Cancer Detection
Young-Eun Choi,Ju-Won Kwak,Joon Won Park
Sensors , 2010, DOI: 10.3390/s100100428
Abstract: Vast numbers of studies and developments in the nanotechnology area have been conducted and many nanomaterials have been utilized to detect cancers at early stages. Nanomaterials have unique physical, optical and electrical properties that have proven to be very useful in sensing. Quantum dots, gold nanoparticles, magnetic nanoparticles, carbon nanotubes, gold nanowires and many other materials have been developed over the years, alongside the discovery of a wide range of biomarkers to lower the detection limit of cancer biomarkers. Proteins, antibody fragments, DNA fragments, and RNA fragments are the base of cancer biomarkers and have been used as targets in cancer detection and monitoring. It is highly anticipated that in the near future, we might be able to detect cancer at a very early stage, providing a much higher chance of treatment.
Magnetic Flux Leakage Sensing-Based Steel Cable NDE Technique
Seunghee Park,Ju-Won Kim,Changgil Lee,Jong-Jae Lee
Shock and Vibration , 2014, DOI: 10.1155/2014/929341
Abstract: Nondestructive evaluation (NDE) of steel cables in long span bridges is necessary to prevent structural failure. Thus, an automated cable monitoring system is proposed that uses a suitable NDE technique and a cable-climbing robot. A magnetic flux leakage- (MFL-) based inspection system was applied to monitor the condition of cables. This inspection system measures magnetic flux to detect the local faults (LF) of steel cable. To verify the feasibility of the proposed damage detection technique, an 8-channel MFL sensor head prototype was designed and fabricated. A steel cable bunch specimen with several types of damage was fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. To interpret the condition of the steel cable, magnetic flux signals were used to determine the locations of the flaws and the levels of damage. Measured signals from the damaged specimen were compared with thresholds that were set for objective decision-making. In addition, the measured magnetic flux signals were visualized as a 3D MFL map for intuitive cable monitoring. Finally, the results were compared with information on actual inflicted damages, to confirm the accuracy and effectiveness of the proposed cable monitoring method. 1. Introduction Recently, there have been increasing demands on structural health monitoring (SHM) and nondestructive testing (NDT) in the fields of civil, mechanical, and aerospace engineering. Especially, local monitoring methodologies for specific critical members have been studied to overcome the limitation of global monitoring techniques for whole structures [1–4]. Steel cables in long span bridges are also critical members that suspend almost all of the dead load of the structure. However, cross-sectional damage can occur in a steel cable due to corrosion and fracture, which can lead to stress concentrations. Cross-sectional damage can be a direct cause of structural failure. Therefore, nondestructive evaluation (NDE) is necessary to detect the initial stages of cross-sectional damage in a cable. However, it is difficult to monitor the condition of most cables, as the damage can be invisible and inaccessibly located. To overcome these drawbacks, we propose an automated cable monitoring system, which uses a suitable NDE technique and a cable-climbing robot that can approach the damaged point, which is shown in Figure 1. Figure 1: The cable-climbing robot with suitable NDE equipment. Meanwhile, NDE techniques available for incorporation into cable-climbing robots have been widely researched. In this study,
The effect of dimiristoylphosphatidylethanol on the rotational mobility of n-(9-Anthroyloxy) stearic acid in neuronal and model membranes  [PDF]
Young-Sik Park, No-Soo Park, Jun-Bong Seo, Soo-Kyoung Bae, You-Kwang kim, Ki-Soo Seong, Young-Jun Kim, Ju-Won Park, Joung-Moung Shin, Young-Chan Jeon, In-Kyo Chung, Moon-Kyoung Bae, Hye-Ock Jang, Il Yun
Journal of Biophysical Chemistry (JBPC) , 2010, DOI: 10.4236/jbpc.2010.13016
Abstract: The aim of this study was to provide a basis for examining the molecular mechanism for the pharmacological action of ethanol. We studied di¬myristoyl¬phosphatidylethanol (DMPEt)’s effects on specific locations of n-(9-anthroyloxy) palmitic acid or stearic acid (n-AS) within phos¬pholipids of synaptosomal plasma membrane vesicles isolated from bovine cerebral cortex (SPMV) and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from SPMV. DMPEt increased rotational mobility (increased disordering) of hydrocarbon interior, but it decreased mobility (increased ordering) of membrane interface, in native and model membranes. The degree of rotational mobility in accordance with the carbon atom numbers of phospholipids comprising neuronal membranes was in the order at the 16, 12, 9, 6 and 2 position of aliphatic chain present in phospholipids. The sensitivity of increasing or decreasing effect of rotational mobility of hydrocarbon interior or surface region by DMPEt differed depending on the neuronal and model membranes in the descending order of SPMV, SPMVPL and SPMVTL.
Phosphokinase Antibody Arrays on Dendron-Coated Surface
Ju-Won Kwak, Hyobin Jeong, Sun-Ho Han, Youngkyu Kim, Sung Min Son, Inhee Mook-Jung, Daehee Hwang, Joon Won Park
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0096456
Abstract: Monitoring protein phosphorylation at the cellular level is important to understand the intracellular signaling. Among the phosphoproteomics methods, phosphokinase antibody arrays have emerged as preferred tools to measure well-characterized phosphorylation in the intracellular signaling. Here, we present a dendron-coated phosphokinase antibody array (DPA) in which the antibodies are immobilized on a dendron-coated glass slide. Self-assembly of conically shaped dendrons well-controlled in size and structure resulted in precisely controlled lateral spacing between the immobilized phosphosite-specific antibodies, leading to minimized steric hindrance and improved antigen-antibody binding kinetics. These features increased sensitivity, selectivity, and reproducibility in measured amounts of protein phosphorylation. To demonstrate the utility of the DPA, we generated the phosphorylation profiles of brain tissue samples obtained from Alzheimer's disease (AD) model mice. The analysis of the profiles revealed signaling pathways deregulated during the course of AD progression.
Glycyrrhizin Alleviates Neuroinflammation and Memory Deficit Induced by Systemic Lipopolysaccharide Treatment in Mice
Jeong-Ho Song,Ju-Won Lee,Beomsoo Shim,Chang-Yeol Lee,Sooyong Choi,Chulhun Kang,Nak-Won Sohn,Jung-Won Shin
Molecules , 2013, DOI: 10.3390/molecules181215788
Abstract: The present study investigated the effects of glycyrrhizin (GRZ) on neuroinflammation and memory deficit in systemic lipopolysaccharide (LPS)-treated C57BL/6 mice. Varying doses of GRZ was orally administered (10, 30, or 50 mg/kg) once a day for 3 days before the LPS (3 mg/kg) injection. At 24 h after the LPS injection, GRZ significantly reduced TNF-α and IL-1β mRNA at doses of 30 and 50 mg/kg. COX-2 and iNOS protein expressions were significantly reduced by GRZ at doses of 30 and 50 mg/kg. In the Morris water maze test, GRZ (30 mg/kg) significantly prolonged the swimming time spent in the target and peri-target zones. GRZ also significantly increased the target heading and memory score numbers. In the hippocampal tissue, GRZ significantly reduced the up-regulated Iba1 protein expression and the average cell size of Iba1-expressing microglia induced by LPS. The results indicate that GRZ ameliorated the memory deficit induced by systemic LPS treatment and the effect of GRZ was found to be mediated through the inhibition of pro-inflammatory mediators and microglial activation in the brain tissue. This study supports that GRZ may be a putative therapeutic drug on neurodegenerative diseases associated with cognitive deficits and neuroinflammation such as Alzheimer’s disease.
Quantitative differentiation of phenolic compounds in different varieties of buckwheat cultivars from China, Japan and Korea  [PDF]
Jeong Min Seo, Da Bin Lee, Mariadhas Valan Arasu, Qi Wu, Tatsuro Suzuki, Young-Ho Yoon, Sang-Won Lee, Sang Un Park, Sun-Ju Kim
Journal of Agricultural Chemistry and Environment (JACEN) , 2013, DOI: 10.4236/jacen.2013.24016
Abstract: The aim of this study was to determine the variation of phenolic compounds in common and tartary buckwheats collected from China, Japan and Korea. Two buckwheat varieties of each country were cultivated using nutrient solution and vermiculite in the greenhouse from February to May, 2012 and harvested at two-week intervals. Phenolics such as chlorogenic acid, C-glycosylflavones (orientin, isoorientin, vitexin, and isovitexin), rutin, and quercetin were quantified using high performance liquid chroma-tography (HPLC). At 17, 29, 44, 58, and 72 days after sowing (DAS), before harvesting each organs, rutin content of cultivars from China and Korea at 17 DAS was the highest (mean 43.63 and 39.95 mg?g–1 DW, respectively) than that of 29 and 44 DAS. However, two varieties from Japan at 44 DAS were documented maximum; whereas, the amount of rutin in “Hokkai T10” harvested at 44 DAS (58.36 mg?g–1 DW) was the highest of all cultivars. Rutin level in the leaves and stems at 72 DAS were comparatively higher than at 58 DAS. The highest of rutin content was found at 72 DAS (73.33 mg?g–1 DW) in “Hokkai T10” leaves followed by “Daegwan No.3-3” (61.13 mg?g–1 DW), “rice tartary” (53.89 mg?g–1 DW). Rutin content of flowers was presented as the highest amount in “Hokkai T10” at 72 DAS (88.3 mg?g–1 DW) was approximately 14-fold higher than that of 58 DAS (6.44 mg?g–1 DW). However, rutin content of flower in “Xiqiao No.2” was 3-fold higher at 72 DAS than at 58 DAS. Rutin and total phenolic compounds content in flowers, leaves, and stems were higher in the order. The content of four C-glycosylflavones in common buckwheat was higher than those in tartary buckwheat, but rutin content which accounted >90% of the total phenolic compounds was higher in tartary buckwheat. The highest amounts of chlorogenic acid and quercetin were measured in the flower of “Xiqiao No.2” (6.85 and 11.69 mg?g–1 DW, respectively). Based on these results, the presence of different phenolic compounds in all the varieties of buckwheat confirmed that it can be regarded as a potent source of functional foods.
Optimal synthesis and characterization of Ag nanofluids by electrical explosion of wires in liquids
Ju Park Eun,Won Lee Seung,Bang In Cheol,Park Hyung Wook
Nanoscale Research Letters , 2011,
Abstract: Silver nanoparticles were produced by electrical explosion of wires in liquids with no additive. In this study, we optimized the fabrication method and examined the effects of manufacturing process parameters. Morphology and size of the Ag nanoparticles were determined using transmission electron microscopy and field-emission scanning electron microscopy. Size and zeta potential were analyzed using dynamic light scattering. A response optimization technique showed that optimal conditions were achieved when capacitance was 30 μF, wire length was 38 mm, liquid volume was 500 mL, and the liquid type was deionized water. The average Ag nanoparticle size in water was 118.9 nm and the zeta potential was -42.5 mV. The critical heat flux of the 0.001-vol.% Ag nanofluid was higher than pure water.
Analysis of the Asymmetric Gene Expression between the Left and Right Hemispheres of Drosophila Brain  [PDF]
Won-Ju Chung
Journal of Behavioral and Brain Science (JBBS) , 2015, DOI: 10.4236/jbbs.2015.510042
Abstract: Studying the molecular mechanism of brain asymmetry can provide important clues to understand neurological diseases and psychiatric disorders related to brain lateralization. In this paper, asymmetric gene expression in the left/right hemispheres of Drosophila brain was genome-widely analyzed to help understand the molecular mechanism of brain asymmetry. Using microarray analysis of total RNAs of the left/right brain hemispheres, thirty-eight genes were found to be differentially expressed in the left/right hemispheres. This result supports that Drosophila brain is asymmetrical at the molecular level. Among thirty-eight genes, six genes of interests were chosen for further analysis based on their protein structures or previous studies: dpr6, CG13299, CG13068, Lim3, CG43759, and Ir21a. Those six genes encode proteins that serve various functions like neural gene expression, memory control, ion channel, and membrane receptor. Surprisingly, all six genes of interests have their peak expression during the early embryonic stages, suggesting that they may play a role in the developmental stage of brain lateralization. Overall, these findings of differential gene expressions in the left/right brain hemispheres can serve as a basic foundation for further research on the understanding of the molecular mechanism of brain asymmetry.
The H∞ synchronization of nonlinear Bloch systems via dynamic feedback control approach
D.H. Ji,J.H. Koo,S.C. Won,Ju H. Park
中国物理 B , 2011,
Abstract: We consider an H∞ synchronization problem in nonlinear Bloch systems. Based on Lyapunov stability theory and linear matrix inequality formulation, a dynamic feedback controller is designed to guarantee asymptotic stability of the master-slave synchronization. Moreover, this controller reduces the effect of an external disturbance to the H∞ norm constraint. A numerical example is given to validate the proposed synchronization scheme.
Prognostic and Predictive Value of KRAS Mutations in Advanced Non-Small Cell Lung Cancer
Jong-Mu Sun, Deok Won Hwang, Jin Seok Ahn, Myung-Ju Ahn, Keunchil Park
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064816
Abstract: Clinical implications of KRAS mutations in advanced non-small cell lung cancer remain unclear. We retrospectively evaluated the prognostic and predictive value of KRAS mutations in patients with advanced NSCLC. Among 484 patients with available results for both KRAS and EGFR mutations, 39 (8%) had KRAS and 182 (38%) EGFR mutations, with two cases having both mutations. The median overall survivals for patients with KRAS mutations, EGFR mutations, or both wild types were 7.7, 38.0, and 15.0 months, respectively (P<0.001). The KRAS mutation was an independent poor prognostic factor in the multivariate analysis (hazard ratio = 2.6, 95% CI: 1.8–3.7). Response rates and progression-free survival (PFS) for the pemetrexed-based regimen in the KRAS mutation group were 14% and 2.1 months, inferior to those (28% and 3.9 months) in the KRAS wild type group. KRAS mutation tended to be associated with inferior treatment outcomes after gemcitabine-based chemotherapy, while there was no difference regarding taxane-based regimen. Although the clinical outcomes to EGFR tyrosine kinase inhibitors (TKIs) seemed to be better in patients with KRAS wild type than those with KRAS mutations, there was no statistical difference in response rates and PFS according to KRAS mutation status when EGFR mutation status was considered. Two patients with both KRAS and EGFR mutations showed partial response to EGFR TKIs. Although G12D mutation appeared more frequently in never smokers, there was no difference in clinical outcomes according to KRAS genotypes. These results suggested KRAS mutations have an independent prognostic value but a limited predictive role for EGFR TKIs or cytotoxic chemotherapy in advanced NSCLC.
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