• Journal of Korea Multimedia Society
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• v.18 no.3
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• pp.387-400
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• 2015

A fuzzy logic based mobile robot navigation system was developed to improve the driving ability without trapping inside obstacles in complex terrains, which is one of the most concerns in robot navigation in unknown terrains. The navigation system utilizes the data from ultrasonic sensors to recognize the distances from obstacles and the position information from a GPS sensor. The fuzzy navigation system has two groups of behavior rules, and the robot chooses one of them based on the information from sensors while navigating for the targets. In plain terrains the robot with the proposed algorithm uses one rule group consisting of behavior rules for avoiding obstacle, target steering, and following edge of obstacle. Once trap is detected the robot uses the other rule group consisting of behavior rules strengthened for following edge of obstacle. The output signals from navigation system control the speed of two wheels of the robot through the fuzzy logic data process. The test was conducted in the Matlab based mobile robot simulator developed in this study, and the results show that escaping ability from obstacle is improved.

• Journal of The Korean Astronomical Society
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• v.52 no.1
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• pp.23-30
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• 2019

The KVN(Korean VLBI Network)-style simultaneous multi-frequency receiving mode is demonstrated to be promising for mm-VLBI observations. Recently, other Very long baseline interferometry (VLBI) facilities all over the globe start to implement compatible optics systems. Simultaneous dual/multi-frequency VLBI observations at mm wavelengths with international baselines are thus possible. In this paper, we present the results from the first successful simultaneous 22/43 GHz dual-frequency observation with KaVA(KVN and VERA array), including images and astrometric results. Our analysis shows that the newly implemented simultaneous receiving system has brought a significant extension of the coherence time of the 43 GHz visibility phases along the international baselines. The astrometric results obtained with KaVA are consistent with those obtained with the independent analysis of the KVN data. Our results thus confirm the good performance of the simultaneous receiving systems for the nonKVN stations. Future simultaneous observations with more global stations bring even higher sensitivity and micro-arcsecond level astrometric measurements of the targets.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.98-103
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• 2014

Purpose: The effective half life of I-131 is useful to calculate radiation dose, period of hospitalization, and exposure dose of surrounding people from patient. However, it is difficult to measure. This study estimates the effective half life in whole body and thyroid in using of value of residual radioactivity obtained from the early and delay images of Dual time I-131 whole body scan. Also, the correlations between the effective half life and serum creatinine, GFR, and administration dose were investigated in this study. Materials and Methods: The targets were 50 patients administration high dose of I-131 from February to August in 2013, having normal range of serum creatinine and over $30{\mu}IU/mL$ of TSH levels. After administration radioactive I-131, the early scan in the 3rd day and the delay scan in the 5-6th days were performed. To measure the residual radioactivity in the whole body and thyroid, ROI was set and then background radioactivity was corrected to estimate. The effective half life was estimated by calculating the ratio of measured values between the early and delay images. To compare the effective half lives of the whole body and thyroid, it was analyzed by Independent t-test, and each correlation of the effective half life, GFR, serum creatinine, and the dose of administration were analyzed by calculating the pearson's correlation coefficient. All of the analysis were determined to be statistically significant when P<0.05. Results: The effective half life of the whole body was $17.06{\pm}5.50$ hours and of the thyroid was $17.22{\pm}5.41$ hours. The two effective half life did not show significant difference (P=0.887). As the value of GFR was increased, the effective half life of whole body (r=-0.407, P=0.003) and of thyroid (r=-0.473, P=0.001) were significantly decreased; as the value of serum creatinine was increased, the effective half life of whole body (r=0.309, P=0.029) and of thyroid (r=0.371, P=0.008) were significantly increased. In the administration dose, effective half life did not have correlations. Conclusion: The effective half life of I-131 of patients treated for their thyroids were estimated only by using the images of Dual time I-131 whole body scan. Also, the correlations with the effective life, GFR, and serum creatinine were examined. This study might be utilized for a study on optimization for the period of hospitalization of patients treated by high dose of I-131 and on evaluation for internal absorbed dose of MIRD schema in application of the effective half life.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.267-271
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• 2009

Multicomponent transparent conducting oxide films were deposited on glass substrates at 150 by dual magnetron sputtering of AZO and ITO targets. In the case of mixing a limited amount of ITO (10W), resistivity of TCO films was significantly increased compared to the AZO film; from $3.5{\times}10^{-3}$ to $9.7{\times}10^{-3}{\Omega}{\cdot}cm$. Deterioration of the electrical conductivity is attributed to the decreases in carrier concentration and Hall mobility. Improvement of the conductivity could be obtained for the films prepared with ITO powers larger than 40 W. The lowest resistivity ($\rho$) of $7.3{\times}10^{-4}{\Omega}{\cdot}cm$ was achieved when ITO power was 100 W. Effects of $H_2$ incorporation on the electrical and optical properties of AZO-ITO films were investigated in this work. Addition of small amount of hydrogen resulted in the increase of carrier concentration and the improvement of electrical conductivity. It is apparent that the roughness of AZO-ITO films decreases dramatically after the transition of microstructure from polycrystalline to amorphous phase, which gives practical advantages such as an excellent uniformity of surface and a high etching rate. AZO-ITO films grown at sputtering ambient with hydrogen gas are expected to be applicable to optoelectronic devices such as organic light emitting diodes and flexible displays due to their sufficient electrical and structural properties.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.3
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• pp.193-201
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• 2006

Squamous cell carcinoma(SCC) of head and neck(SCCHN) is the sixth most common human malignant tumor. However, despite advances in prevention and treatment of SCC, the five-year survival rates for patients remain still low. To improve the outcome for patients with SCCHN, novel treatment strategies are needed. Overexpression of the epidermal growth factor(EGF) and activation of its receptor(EGFR) are associated with progressive growth of SCCHN. Vascular endothelial growth factor(VEGF) signaling molecules are related with neoangiogenesis and vascular metastasis of SCC. In this study, we determined the therapeutic effect of AEE788(Novartis Pharma AG, Basel, Switzerland), which is a dual inhibitor of EGFR/ErbB2 and VEGFR tyrosine kinases, on human oral SCC. At first, we screened the expression of EGFR, c-ErbB2(HER-2) and VEGFR-2 in a series of human oral SCC cell lines. And then we evaluated the effects of AEE788 on the phosphorylation of EGFR and VEGFR-2 in a oral SCC cell line expressing EGFR/HER-2 and VEGFR-2. We also evaluated the effects of AEE788 alone, or with paclitaxel(Taxol) on the oral SCC cell growth and apoptosis. As a result, all oral SCC cells expressed EGFR and VEGFR-2. Treatment of oral SCC cells with AEE788 led to dose-dependent inhibition of EGFR and VEGFR-2 phosphorylation, growth inhibition, and induction of apoptosis. Moreover, AEE788 sensitizes the cells to paclitaxel-mediated toxicity and apoptosis. These data mean EGFR and VEGFR-2 can be reliable targets for molecular therapy of oral SCC, and therefore warrant clinical use of EGFR/VEGFR inhibition in the treatment of patients with recurrent or metastatic oral SCC.

• BMB Reports
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• v.39 no.5
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• pp.469-478
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• 2006

Vascular endothelial growth factor (VEGF)-A, a major regulator for angiogenesis, binds and activates two tyrosine kinase receptors, VEGFR1 (Flt-1) and VEGFR2 (KDR/Flk-1). These receptors regulate physiological as well as pathological angiogenesis. VEGFR2 has strong tyrosine kinase activity, and transduces the major signals for angiogenesis. However, unlike other representative tyrosine kinase receptors which use the Ras pathway, VEGFR2 mostly uses the Phospholipase-$C{\gamma}$-Protein kinase-C pathway to activate MAP-kinase and DNA synthesis. VEGFR2 is a direct signal transducer for pathological angiogenesis including cancer and diabetic retinopathy, thus, VEGFR2 itself and the signaling appear to be critical targets for the suppression of these diseases. VEGFR1 plays dual role, a negative role in angiogenesis in the embryo most likely by trapping VEGF-A, and a positive role in adulthood in a tyrosine kinase-dependent manner. VEGFR1 is expressed not only in endothelial cells but also in macrophage-lineage cells, and promotes tumor growth, metastasis, and inflammation. Furthermore, a soluble form of VEGFR1 was found to be present at abnormally high levels in the serum of preeclampsia patients, and induces proteinurea and renal dysfunction. Therefore, VEGFR1 is also an important target in the treatment of human diseases. Recently, the VEGFR2-specific ligand VEGF-E (Orf-VEGF) was extensively characterized. Interestingly, the activation of VEGFR2 via VEGF-E in vivo results in a strong angiogenic response in mice with minor side effects such as inflammation compared with VEGF-A, suggesting VEGF-E to be a novel material for pro-angiogenic therapy.

• BMB Reports
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• v.43 no.6
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• pp.400-406
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• 2010

Cancer/testis (CT) antigens exhibit highly tissue-restricted expression and are considered promising targets for cancer vaccines. Here we identified a novel CT gene ZNF645 which restrictively expresses in normal human testes and lung cancer patients (68.3%). To investigate the promoter methylation status of ZNF645, we carried out bisulfite genomic sequencing and found that the CpG island in its promoter was heavily methylated in normal lung tissues without the expression of ZNF645, whereas there was high demethylation in normal human testes and lung carcinoma tissues with its expression. Also ZNF645 could be remarkably activated in A549 and HEK293T cells treated by DNA demethylation agent 5'-aza-2'-deoxycytidine. And the dual luciferase assay revealed that the promoter activity of the ZNF645 was inhibited by methylation of the CpG island region. Therefore, we proposed that ZNF645 is a CT gene and activated in human testis and lung cancers by demethylation of its promoter region.

• Molecules and Cells
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• v.41 no.3
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• pp.198-206
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• 2018

Aortic dissection (AD) is a catastrophic disease with high mortality and morbidity, characterized with fragmentation of elastin and loss of smooth muscle cells. Although AD has been largely attributable to polymorphisms defect in the elastin-coding gene, tropoelastin (TE), other undermined factors also appear to play roles in AD onset. Here, we investigated the effects of post-transcriptional control of TE by microRNAs (miRNAs) on elastin levels in aortic smooth muscle cells (ASMC). We found that miR-144-3p is a miRNA that targets TE mRNA in both human and mouse. Bioinformatics analyses and dual luciferase reporter assay showed that miR-144-3p inhibited protein translation of TE, through binding to the 3'-UTR of the TE mRNA. Interestingly, higher miR-144-3p levels and lower TE were detected in the ASMC obtained from AD patients, compared to those from non-AD controls. In a mouse model for human AD, infusion of adeno-associated viruses (serotype 6) carrying antisense for miR-144-3p (asmiR-144-3p) under CAG promoter significantly reduced the incidence and severity of AD, seemingly through enhancement of TE levels in ASMC. Thus, our data suggest an essential role of miR-144-3p on the pathogenesis of AD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.379-380
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• 2007

The characteristics of a co-sputtered indium zinc tin oxide (IZTO) films prepared by dual target dc magnetron sputtering from IZO and ITO targets at a room temperature are investigated. Film properties, such as sheet resistance, optical transmittance, surface work function and surface roughness were examined as a function of ITO dc power at constant IZO dc power of 100 W. It was shown that the increase of the ITO dc power during co-sputtering of ITO and IZO target resulted in an increase of sheet resistance of the IZTO films. This can be attributed to high resistivity of ITO film prepared at room temperature. Surface smoothness and roughness were investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The synchrotron x-ray scattering results obtained from IZTO film with different ITO contents showed that introduction of ITO atoms into amorphous IZO film resulted in a crystallization of IZTO film with (222) preferred orientation due to low alc transition temperature of ITO film. However, the transmittance of the IZTO films with thickness of 150 nm is between 80 and 85 % at wavelength of 550 nm regardless of ITO content. Possible mechanism to explain the ITO and IZO co-sputtering effect on properties of IZTO is suggested.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.25-32
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• 2021

Inflammatory reactions activated by lipopolysaccharide (LPS) of gram-negative bacteria can lead to severe septic shock. With the recent emergence of multidrug-resistant gram-negative bacteria and a lack of efficient ways to treat resulting infections, there is a need to develop novel anti-endotoxin agents. Antimicrobial peptides have been noticed as potential therapeutic molecules for bacterial infection and as candidates for new antibiotic drugs. We previously designed the 9-meric antimicrobial peptide Pro9-3 and it showed high antimicrobial activity against gram-negative bacteria. Here, to further examine its potency as an anti-endotoxin agent, we examined the anti-endotoxin activities of Pro9-3 and elucidated its mechanism of action. We performed a dye-leakage experiment and BODIPY-TR cadaverine and limulus amebocyte lysate assays for Pro9-3 as well as its lysine-substituted analogue and their enantiomers. The results confirmed that Pro9-3 targets the bacterial membrane and the arginine residues play key roles in its antimicrobial activity. Pro9-3 showed excellent LPS-neutralizing activity and LPS-binding properties, which were superior to those of other peptides. Saturation transfer difference-nuclear magnetic resonance experiments to explore the interaction between LPS and Pro9-3 revealed that Trp3 and Tlr7 in Pro9-3 are critical for attracting Pro9-3 to the LPS in the gram-negative bacterial membrane. Moreover, the anti-septic effect of Pro9-3 in vivo was investigated using an LPS-induced endotoxemia mouse model, demonstrating its dual activities: antibacterial activity against gram-negative bacteria and immunosuppressive effect preventing LPS-induced endotoxemia. Collectively, these results confirmed the therapeutic potential of Pro9-3 against infection of gram-negative bacteria.