• Macromolecular Research
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• v.17 no.12
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• pp.1021-1024
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• 2009

We successfully prepared high-flow polycarbonate (PC) by blending commercial PC with a low molecular weight PC oligomer. The oligomer was synthesized by the addition of a large quantity of mono functional phenol groups, and the chain end group was reacted with p-tertiary butyl phenol (PTBP) to block the reactivity. The viscosity average molecular weight ($M_v$) for the oligomer was about 4,000-5,000 g/mol, compared to ~19,000 g/mol for the PC blend obtained by blending 10 wt% of the prepared oligomer with the commercial grade PC ($M_v$ of 21,000 g/mol). The blended PC had a melt flow index of 45, which is 2.5 times higher, and a processing temperature that was $20^{\circ}C$ lower, than that of commercial grade PC having a similar $M_v$.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3743-3748
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• 2013

A tetradentate ligand of 2-phenyl-4,6-di(pyridin-2-yl)pyrimidine (L) has been synthesized and its complexes with $ZnI_2$ and CuI have been obtained by hydrothermal method. single crystal X-ray diffraction analysis indicates that ligand L coordinates with Zn(II) ions to form a simple four-coordinate di-nuclear complex, while the complexation of L with Cu(I) constructs a one-dimensional chain polymer. The existence of $I^-$ ion hampers the L to assemble grid-type complexes with Zn(II) and Cu(I). Fluorescence spectra show that the L emits blue fluorescence while its Cu(I) polymer decrease the fluorescence intensity and Zn(II) complex quenches the fluorescence.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.143-145
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• 1994

Chimeric fusion proteins involving IgG have proven valuable in studying protein-protein interactions and may possess therapeutic applications as well. For example, three receptor subtypes for the natriuretic peptides, when fused to the Fc portion of human IgG ${\gamma}$ chain, were quantitatively and qualitatively indistinguishable from the native receptor, thus allowing detailed structure-function studies of the receptor. In an attempt to block human immunodeficiency virus infectivity with soluble derivatives of CD4, a CD4/IgG Fc chimeric molecule was shown to increase the plasma half life of soluble CD4 and possessed the added advantage of IgG Fc-mediated placental transfer. In the case of the KGFR, this approach provided a framework for dissection of its ligand binding domains and made it possible to demonstrate that high affinity binding sites for two ligands, aFGF and KGF, reside within different receptor Ig-like domains. Chimeric molecules fused to immunoglobulins would have the advantages of secretion from transfected cells as well as detection and purification from medium utilizing Staphylococcus aureus Protein A. In addition, where highly related receptors make their discrimination very hard due to the difficulties in generating specific immunochemical probes, IgG fusion protein with tailor-made specificities confers particular advantages to elucidate patterns of receptor distribution and expression. The approach described here may have general applications in defining ligand-receptor interactions as well as searching for specific agonists and antagonists of receptor function.

• Journal of Arbitration Studies
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• v.28 no.2
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• pp.165-178
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• 2018

Exchanging information with a person without credentials over the Internet does not pose any problems. A decentralized system based on blockchain technology enables the user to exchange new value(currency) with other uncredited users. The blockchain technology creates a new paradigm in which the distribution system can be founded on trust. Various applied distribution systems are being developed based on this paradigm. This study analyzed the problems between an institute's grading system and the central administration system. The limitations of an institute's current central management system were presented through actual cases. To improve the problem, a decentralized system based on block chain technology was presented in order to overcome the fundamental limitations by utilizing blockchain technology, peer-to-peer network, and the distribution system. In the central system, a malicious moderator could create a malicious edit that becomes the cause of a dispute, but in a decentralized system, a problem cannot be created even if there were to be a malicious moderator. However, it is difficult for a single college institute to create a distribution system in order to actualize an effective system. Comparatively, it would be possible to create a decentralized system in which all educational institutes in Korea (elementary schools, middle schools, high schools, colleges) took part in. The application of a decentralized system would improve the public transparency and reliability of educational institutes.

• Journal of Life Science
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• v.17 no.10
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• pp.1361-1367
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• 2007

I investigated the effect of KT5720, an inhibitor of protein kinase A, on the vesicular stomatitis virus (VSV) infection in BHK-21cell cultures. The virus inducted cytopathic effect (CPE) was almost completely suppressed by KT5720 at 5uM. The inhibitor, however, did not affect replication of the virus nor the synthesis of viral macromolecules. KT5720, did not block the cytoskeletal disruption, while the cell rounding was suppressed. And, the KT5720-sensitive function may be involved in developing the VSV-induced CPE, but not essential for the virus replications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.338-343
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• 2006

This paper describes about the design concept and the architecture of an economic VPN system which can perform fast crypto operations with cheap cost. The essence of the proposed system architecture is consisting of the system with two companion chips dedicated to VPN: one chip is a multi-purpose network processor for security machine and the other is a crypto acceleration chip which encrypt and decrypt network packets in a high speed. This study also addresses about some realizations that is required for fast prototyping such as the porting of an operating system, the establishment of compiler tool chain, the implementation of device drivers and the design of IPSec security engine. Especially, the second chip supports the most time consuming block cipher algorithms including 3DES, AES, and SEED and its performance was evaluated.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.129-130
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• 2018

In shipping logistics, despite the fact that it has promoted the information processing process, the use of the document exchange mechanism has caused a problem of increasing the cost and lead time. In recent years, various types of projects are in progress in preparation for full-scale introduction of a blockchain technology capable of solving the document exchange mechanism in the shipping industry, In near future, by expanding the practical application scope, it is aiming to increase competitiveness through transparency, reliability, stability, and efficiency, which are the effects of application of the block chain technology.

• The Korean Journal of Pain
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• v.18 no.1
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• pp.52-55
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• 2005

Complications following a well conducted epidural steroid injection are rare. A 50-year-old man developed a headache and neck stiffness 2 days after a lumbar epidural steroid injection. Under the impression of aseptic meningitis, fluid and nonsteroidal anti-inflammatory drug therapy was started immediately after cerebrospinal fluid (CSF) sampling. The CSF was turbid, and revealed a white blood cell count, protein, glucose and pressure of $550/{\mu}l$ (98% lymphocyte), 107.9 mg/dl, 48 mg/dl (serum 113 mg/dl) and $17cmH_2O$, respectively. The CSF stain and culture, and antibody test and polymerase chain reaction for pathogens were negative. A computed tomography (CT) scan of the brain revealed no abnormality, and a chest roentgenogram and the results of the neurological examination were normal. Under the impression of aseptic meningitis, the condition was managed conservatively, without antibiotics. Seven days later, the clinical symptoms had improved, and the patient discharged.

• Macromolecular Research
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• v.11 no.1
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• pp.2-8
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• 2003

The self-assembly of polymers can lead to supramolecular systems and is related to the their functions of material and life sciences. In this article, self-assembly of Langmuir-Blodgett (LB) films, polymer micelles, and polymeric nanoparticles, and their biomedical applications are described. LB surfaces with a well-ordered and layered structure adhered more cells including platelet, hepatocyte, and fibroblast than the cast surfaces with microphase-separated domains. Extensive morphologic changes were observed in LB surface-adhered cells compared to the cast films. Amphiphilic block copolymers, consisting of poly(${\gamma}$-benzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) [or poly(N-isopropylacrylamide) (PNIPAAm)] as the hydrophilic one, can self-assemble in water to form nanoparticles presumed to be composed of the hydrophilic shell and hydrophobic core. The release characteristics of hydrophobic drugs from these polymeric nanoparticles were dependent on the drug loading contents and chain length of the hydrophobic part of the copolymers. Achiral hydrophobic merocyanine dyes (MDs) were self-assembled in copolymeric nanoparticles, which provided a chiral microenvironment as red-shifted aggregates, and the circular dichroism (CD) of MD was induced in the self-assembled copolymeric nanoparticles.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.873-885
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• 1995

The local structural and thermodynamical properties of blends A-B/H of a diblock copolymer A-B and a homopolymer H are studied using the polymer reference interaction site model (RISM) integral equation theory with the mean-spherical approximation closure. The random phase approximation (RPA)-like static scattering function is derived and the interaction parameter is obtained to investigate the phase transition behaviors in A-B/H blends effectively. The dependences of the microscopic interaction parameter and the macrophase-microphase separation on temperature, molecular weight, block composition and segment size ratio of the diblock copolymer, density, and concentration of the added homopolymer, are investigated numerically within the framework of Gaussian chain statistics. The numerical calculations of site-site interchain pair correlation functions are performed to see the local structures for the model blends. The calculated phase diagrams for A-B/H blends from the polymer RISM theory are compared with results by the RPA model and transmission electron microscopy (TEM). Our extended formal version shows the different feature from RPA in the microscopic phase separation behavior, but shows the consistency with TEM qualitatively. Scaling relationships of scattering peak, interaction parameter, and temperature at the microphase separation are obtained for the molecular weight of diblock copolymer. They are compared with the recent data by small-angle neutron scattering measurements.