• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.2
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• pp.1-9
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• 2011

Several studies on the development for solar powered uninhabited aerial vehicles(UAVs) are under way as the use of the renewable energy becomes more and more important these days. This paper is for the conceptual design by a discrete and iterative method. An initial design point with 1.5 meter wing span is determined in the global design, which deploys the mass and energy balances among each component of UAV including solar cells and airframe. Then, the iteration for subsystems is carried out with the help of Vortex Lattice Method(VLM) to optimize the aircraft configuration and the solar power system. It is demonstrated in simulations that the optimized design increases the flight time from 62 to 120 minutes when the solar power system is installed. Also, the associated dynamic analysis reveals that the designed small aircraft has the acceptable stability and controllability.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.276-276
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• 2012

The interface morphology of organic active layers is known to play a crucial role in the performance of organic photovoltaic (OPV) cells. Especially, a controlled nanostructure with a large contact area between electron donor (D) and acceptor (A) layers is necessary to improve the power conversion efficiency (PCE) of the cells since the short exciton diffusion lengths in organic semiconductors limit the charge (hole and electron) separation before excitons recombination. In this work, we developed simple solvent treating methods to fabricate a nanostructured DA interface and applied them to enhance the PCE of ZnPc/C60 based small molecule OPV cells. Interestingly, it was observed that the solvent treatment on the donor layer prior to the deposition of the acceptor layer resulted in a significant decrease in PCE, which was due to an existence of undesirable voids at the DA interface. Instead, the solvent vapor treatment after the DA bilayer formation led to densely packed and well dispersed DA contacts. Consequently, 3-fold enhancement of PCE as compared to the untreated bilayer cell was accomplished.

• Journal of Microbiology
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• v.43 no.2
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• pp.179-182
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• 2005

The inefficiency of in vivo gene transfer using currently available vectors reflects a major hurdle in cancer gene therapy. Both viral and non-viral approaches that improve gene transfer efficiency have been described, but suffer from a number of limitations. Herein, a fiber-modified adenovirus, carrying the small peptide ligand on the capsid, was tested for the delivery of a transgene to cancer cells. The fiber-modified adenovirus was able to mediate the entry and expression of a $\beta$-galactosidase into cancer cells with increased efficiency compared to the unmodified adenovirus. Particularly, the gene transfer efficiency was improved up to 5 times in OVCAR3 cells, an ovarian cancer cell line. Such transduction systems hold promise for delivering genes to transferrin receptor overexpressing cancer cells, and could be used for future cancer gene therapy.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.269-276
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• 2016

Public Safty-LTE(Long Term Evolution) is being deployed in the direction of reducing cost by using both of municipal network and commercial network. However, LTE Network is difficult to ensure the survivability during the information communication infrastructure failures. In addition, it is vulnerable in communication coverage of inside buildings and underground. In this study, we propose to implement effectively the network survivability technique through the convergence to the proven technology. As the advent of the IoT Age, smart sensors which are embedded in the environment and the things will be able to provide a useful infrastructure for ensuring the network survivability. Based on the feature of the smart sensor, we designed the sink node architecture to guarantee the network survivability in disaster situation through the convergence of the small cell technology and extension of wireless network coverage technology. The computing power inherent in the environment is a valuable resource that can be utilized in the disaster situation.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2979-2984
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• 2012

Recent studies have indicated a link between levels of cyclooxygenase-2 (COX-2) and development of the multidrug resistance (MDR) phenotype. The ATP-binding cassette sub-family G member 2 (ABCG2) is a major MDR-related transporter protein that is frequently overexpressed in cancer patients. In this study, we aimed to evaluate any positive correlation between COX-2 and ABCG2 gene expression using the COX-2 inducer 12-O-tetradecanoylphorbol-13-acetate (TPA) in human breast cancer cell lines. ABCG2 mRNA and protein expression was studied using real-time RT-PCR and flow cytometry, respectively. A significant increase of COX-2 mRNA expression (up to 11-fold by 4 h) was induced by TPA in MDA-MB-231 cells, this induction effect being lower in MCF-7 cells. TPA caused a considerable increase up to 9-fold in ABCG2 mRNA expression in parental MCF-7 cells, while it caused a small enhancement in ABCG2 expression up to 67 % by 4 h followed by a time-dependent decrease in ABCG2 mRNA expression in MDA-MB-231 cells. TPA treatment resulted in a slight increase of ABCG2 protein expression in MCF-7 cells, while a time-dependent decrease in ABCG2 protein expression was occurred in MDA-MB-231 cells. In conclusion, based on the observed effects of TPA in MDA-Mb-231 cells, it is proposed that TPA up-regulates ABCG2 expression in the drug sensitive MCF-7 breast cancer cell line through COX-2 unrelated pathways.

• Tuberculosis and Respiratory Diseases
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• v.67 no.1
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• pp.8-13
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• 2009

Background: The insulin receptor substrate-1 (IRS-1) is the primary docking molecule for the insulin-like growth factor I receptor (IGF-IR), and is required for activation of the phosphatidylinositol 3'-kinase (PI3K) pathway. IRS-1 activation of the (PI3K) pathway regulates IGF-mediated survival, enhancement of cellular motility and apoptosis. Therefore, we attempted to ascertain whether IRS-1 genetic variations affect an individual's risk for non-small cell lung cancer (NSCLC). Methods: Two-hundred and eighteen subjects, either diagnosed with NSCLC or control subjects, were matched by age, gender and smoking status. Genomic DNA from each subject was amplified by PCR and analyzed according to the restriction fragment length polymorphism (RFLP) profile to detect the IRS-1 G972R polymorphism. Results: The frequencies of each polymorphic variation, in the control population, were as follows: GG=103 (94.5%) and GR=6 (5.5%); for the NSCLC subjects, the genotypic frequencies were as follows: GG=106 (97.2%) and GR=3 (2.8%). We could not demonstrate statistically significant differences in the genotypic distribution between the NSCLC and the control subjects (p=0.499, Fisher's Exact test). The relative risk of NSCLC, associated with the IRS-1 G972R polymorphic variation, was 1.028 (95% CI; 0.63~9.90). In addition, we found no differences between polymorphic variants with regard to the histological subtype of NSCLC. Conclusion: We did not observe any noteworthy differences in the frequency of the IRS-1 G972R polymorphism in NSCLC patients, compared to control subjects. These results suggest suggesting that, in our study population, the IRS-1 G972R polymorphism does may not appear to be associated with an increased risk of NSCLC.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.73.1-73.1
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• 2010

For the successful cold starting of a fuel cell engine, either internal of external heat supply must be made to overcome the formation of ice from water below the freezing point of water. In the present study, switchable vanadium oxide compounds as variable temperature-electrical resistance materials onto the surface of flat metallic bipolar plates have been prepared by a dip-coating technique via an aqueous sol-gel method. Subsequently, the chemical composition and micro-structure of the polycrystalline solid thin films were analyzed by X-ray diffraction, X-ray fluorescence spectroscopy, and field emission scanning electron microscopy. In addition, it was carefully measured electrical resistance hysteresis loop over a temperature range from $-20^{\circ}C$ to $80^{\circ}C$ using the four-point probe method. The experimental results revealed that the thin films was mainly composed of Karelianite $V_2O_3$ which acts as negative temperature coefficient materials. Also, it was found that thermal dissipation rate of the vanadium oxide thin films partially satisfy about 50% saving of the substantial amount of energy required for ice melting at $-20^{\circ}C$. Moreover, electrical resistances of the vanadium-based materials converge on an extremely small value similar to that of pure flat metallic bipolar plates at higher temperature, i.e. $T{\geq}40^{\circ}C$. As a consequence, experimental studies proved that it is possible to apply the variable temperature-electrical resistance material based on vanadium oxides for the cold starting enhancement of a fuel cell vehicle and minimize parasitic power loss and eliminate any necessity for external equipment for heat supply in freezing conditions.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.525-534
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• 2005

Adsorption experiments for As(V) and As(III) onto the surfaces of aerobic Pseudomonas aeruginosa, which can be readily isolated from natural media, were conducted under nutrient-absent conditions. While a small amount of As(III) was adsorbed on the bacterial cell surfaces, As(V) was not effectively removed from the solution through adsorption. The result was likely due to the electrostatic repulsion between anionic compounds of aqueous As(V) and cell surfaces of f aeruginosa. However, the bacteria forming biofilm reduced a large amount of aqueous As(V) to As(III), which indicated that microorganisms in most oligotrophic, natural geologic settings can mediate the behavior of aqueous As. Biobarriers designed to remove the various heavy metals in contaminant plume may practically lead to the enhancement of toxicity and mobility of As.

• Journal of Veterinary Clinics
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• v.39 no.4
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• pp.168-172
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• 2022

A 10-year-old female Pomeranian weighing 2.25 kg with a history of gradual weight loss and an intraabdominal mass confirmed with ultrasonography at a local hospital was referred to the Veterinary Medical Teaching Hospital, Jeju National University. Physical examination revealed abdominal distention. Blood analysis revealed hypoglycemia (57 mg/dL; reference range, 60-110 mg/dL). On abdominal ultrasonography, a heterogeneously hyperechoic mass measuring 7.51 × 10.6 cm was found at the level of the left kidney. Computed tomographic findings showed a unilateral left kidney mass with a 10-cm diameter and vessel contrast enhancement in the corticomedullary phase. Unilateral nephrectomy and ovariohysterectomy were performed because left ovary enlargement was observed during surgery. The renal mass was adjacent to the aorta and vena cava and attached to a portion of the small intestine, greater omentum, and left ovary. The mass was huge (12.5 × 10 × 7 cm) and was 16.5% of the body weight. Histopathological examination revealed renal cell carcinoma (RCC) and ovarian metastasis. After surgery, clinical signs improved remarkably, and serum glucose level returned to normal. As RCC is resistant to radiation and chemotherapy, the owner decided not to proceed with postoperative adjunctive therapies. To the best of our knowledge, this is the first case report of ovarian metastasis with huge RCC in a dog.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.29-35
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• 2003

A crude polysaccharide fraction (GU-3) from the roots of Glycyrrhiza uralensis (licorice root), a screened herbal plant used in the preparation of herbal kimchi, enhanced Peyer's patch mediated bone marrow cell proliferation and NK cell-mediated tumor cytotoxicity against Yac-1 cells. GU-3 was further purified by DEAE-Sepharose CL-6B yielding fractions designated as GU-3I, and 3IIa∼3IIe. GU-3IIa is mainly composed of arabinose, galactose and galacturonic acid, and showed the highest bone marrow cell proliferation activity. In addition, GU-3IIb had arabinose, galactose, rhamnose and galacturonic acid as the component sugars with a small quantity of protein; GU-3IIb also enhanced activity of NK cell-mediated tumor cytotoxicity. After these fractions were further fractionated via gel filtration on Sepharose CL-6B or Sephacryl S-300, two immunological active polysaccharides, GU-3IIa-2 and 3IIb-1 were purified from the respective fractions. GU-3IIa-2 mostly contained neutral sugars (75%) such as arabinose and galactose (molar ratio; 1.0 : 0.7) in addition to a considerable amount of galacturonic acid (20%), whereas GU-3IIb-1 was composed of arabinose, galactose, rhamnose and galacturonic acid (molar ratio; 0.3 : 0.5 : 0.1 : 1.0). Methylation analysis indicated that GU-3IIa-2 was composed mainly of terminal, 4- or 5-linked and 3,4- or 3,5-branched arabinose, 3-linked, 4-linked and 3,6-branched galactose, and terminal and 4-linked galacturonic acid whereas GU-3IIb-1 contained various glycosidic linkages such as terminal and 4- or 5-linked arabinose, 2,4-branched rhamnose, terminal and 4-linked galactose, and terminal and 4-galacturonic arid. Single radial gel diffusion indicated that only GU-3IIa-2 strongly reacted with β-D-glucosyl-Yariv antigen. These results suggest that bone marrow cell proliferating activity and enhancement of NK cell-mediated tumor cytotoxicity of GU-3 are caused by polysaccharides containing a pectic arabinogalactan (GU-3IIa-2) and pectic polysaccharide (GU-3IIb-1).