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Daegu, South Korea

Xu W.,Kyungpook National University | Bony B.A.,Kyungpook National University | Kim C.R.,Kyungpook National University | Bae J.E.,KNU | And 2 more authors.
Scientific Reports | Year: 2013

There is no doubt that the molecular imaging is an extremely important technique in diagnosing diseases. Dual imaging is emerging as a step forward in molecular imaging technique because it can provide us with more information useful for diagnosing diseases than single imaging. Therefore, diverse dual imaging modalities should be developed. Molecular imaging generally relies on imaging agents. Mixed lanthanide oxide nanoparticles could be valuable materials for dual magnetic resonance imaging (MRI)-fluorescent imaging (FI) because they have both excellent and diverse magnetic and fluorescent properties useful for dual MRI-FI, depending on lanthanide ions used. Since they are mixed nanoparticles, they are compact, robust, and stable, which is extremely useful for biomedical applications. They can be also easily synthesized with facile composition control. In this study, we explored three systems of ultrasmall mixed lanthanide (Dy/Eu, Ho/Eu, and Ho/Tb) oxide nanoparticles to demonstrate their usefulness as dual T 2 MRI-FI agents. Source

Bony B.A.,Kyungpook National University | Baeck J.S.,Kyungpook National University | Chang Y.,Kyungpook National University | Bae J.E.,KNU | And 2 more authors.
Bulletin of the Korean Chemical Society | Year: 2015

An ideal T1 MRI contrast agent should have a large r1 value and r2/r1 ratio, which is close to 1. In this study, a new approach to accomplish this is presented using the mixed Cu(II)/Gd(III) oxide nanoparticle. The D-glucuronic acid-coated Cu(II)/Gd(III) oxide nanoparticle showed r1 = 13.78 mM-1 s-1 and r2 = 14.48 mM-1 s-1 (r2/r1 = 1.05). This result is due to reduced magnetization of mixed nanoparticle resulting from mixing of nearly nonmagnetic Cu(II) into the nanoparticle. This result shows that the D-glucuronic acid-coated Cu(II)/Gd(III) oxide nanoparticle is a potential T1 MRI contrast agent. © 2015 Korean Chemical Society, Seoul & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Park J.Y.,Kyungpook National University | Kim S.J.,Kyungpook National University | Lee G.H.,Kyungpook National University | Bae J.E.,KNU | Chae K.S.,Teachers College
Journal of the Korean Physical Society | Year: 2015

Surface coating of nanoparticles with ligands is essential in magnetic resonance imaging (MRI) because of solubility in water and biocompatibility. In this study, five organic molecules were used for surface coating of ultrasmall gadolinium-oxide (Gd2O3) nanoparticles (davg = 2.0 nm). All of the samples showed large longitudinal (r1) and transverse (r2) water proton relaxivities with r2/r1 ratios that were close to one, corresponding to ideal conditions for T1 MRI contrast agents. Finally, in-vivo T1 MR images were acquired to prove the effectiveness of the surface-coated ultrasmall Gd2O3 nanoparticles as a T1 MRI contrast agent. © 2015, The Korean Physical Society. Source

Jung H.,ETRI | Gohar M.,KNU | Kim J.-I.,KNU | Koh S.-J.,KNU
IEICE Transactions on Communications | Year: 2011

In future mobile networks, the ever-increasing loads imposed by mobile Internet traffic will force the network architecture to be changed from hierarchical to flat structure. Most of the existing mobility protocols are based on a centralized mobility anchor, which will process all control and data traffic. In the flat network architecture, however, the centralized mobility scheme has some limitations, such as unwanted traffic flowing into the core network, service degradation by a single point of failure, and increased operational costs, etc. This paper proposes mobility schemes for distributed mobility control in the flat network architecture. Based on the Proxy Mobile IPv6 (PMIP), which is a well-known mobility protocol, we propose the three mobility schemes: Signal-driven PMIP (S-PMIP), Data-driven Distributed PMIP (DD-PMIP), and Signal-driven Distributed PMIP (SD-PMIP). By numerical analysis, we show that the proposed distributed mobility schemes can give better performance than the existing centralized scheme in terms of the binding update and packet delivery costs, and that SD-PMIP provides the best performance among the proposed distributed schemes. © 2011 The Institute of Electronics, Information and Communication Engineers. Source

Kim C.R.,Kyungpook National University | Bae J.E.,KNU | Chae K.S.,KNU | Chae K.S.,Teachers College | Lee G.H.,Kyungpook National University
Physical Chemistry Chemical Physics | Year: 2014

The dependence of longitudinal (r1) and transverse (r 2) water proton relaxivities of ultrasmall gadolinium oxide (Gd 2O3) nanoparticles on the surface coating ligand-size was investigated. Both r1 and r2 values decreased with increasing ligand-size. We attributed this to the ligand-size effect. In addition the effectiveness of d-glucuronic acid-coated ultrasmall Gd 2O3 nanoparticles as T1 magnetic resonance imaging (MRI) contrast agents was confirmed by measuring the in vitro cytotoxicity and using in vivo T1 MR images in a mouse in a 1.5 T MR field. © the Partner Organisations 2014. Source

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