• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.115-124
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• 2005

We propose a new binding update(BU) protocol between mobile node(CN) and correspondent node(CN) for the purpose of preventing redirect attacks and DoS attacks observed from the existing BU protocols and enhancing the efficiency of the BU protocol. Home agent plays a role of both authentication server validating BU message and session key distribution center for MN and CN. Also propose the stateless Diffie-Hellman key agreement based on cryptographically generated address (CGA). Suity of our proposed Protocol is analyzed and compared with other protocols. The proposed protocol is more efficient than previous schemes in terms of the number of message flows and computation overhead and is secure against both redirect and DoS attacks.

• Polymer(Korea)
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• v.39 no.1
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• pp.169-173
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• 2015

Metallocene was supported on the silica, which was functionalized with aminosilanes such as aminopropyltrimethoxysilane (1NS) or N-[3-(trimethoxysilyl)propyl]ethylenediamine (2NS), and ionic liquids such as 1-butyl-4-methylpyridinium chloride (Cl), tributylmethylammonium chloride (Amm), benzyldimethyltetradecylammonium chloride (Ben), 1-butyl-1-methylpyrrolidinium chloride (Pyr), and then ethylene polymerizations were performed. The Zr contents of $SiO_2/1NS/IL/(n-BuCp)_2ZrCl_2$ and $SiO_2/2NS/IL/(n-BuCp)_2ZrCl_2$ were lower than those of only aminosilane-treated silicas. However, the polymerization activity of $SiO_2/1NS/IL/(n-BuCp)_2ZrCl_2$ was higher than that of $SiO_2/1NS/(n-BuCp)_2ZrCl_2$. The polymerization activity of $SiO_2/2NS/IL/(n-BuCp)_2ZrCl_2$ was lower than that of $SiO_2/2NS/(n-BuCp)_2ZrCl_2$ due to much lower Zr content.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.250-258
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• 1980

Various radicals may add to isonitriles to give imidoyl radcals RN=CR'. This may be also generated via abstraction of imidoyl hydrogen from imine in the following manner: RN=CR' ＋ R"${\cdot}{\rightarrow}$ RN=CR' ＋ R"-H Imidoyl radicals would be stabilized via two pathways, ${\beta}$-cleavage and atom transfer reactions. ${\beta}$-Cleavage may occur in two directions depending upon structure of the radicals. Cyanide transfer and the "so-called" normal ${\beta}$-cleavage are the two modes of ${\beta}$-cleavage. Addition of t-butoxy radical to t-butyl isocyanide 7 generates an imidoyl radical t-Bu-N=C-O-Bu-t, which undergoes ${\beta}$-cleavage to give t-butyl isocyanate and t-butyl radical. Addition of phenyl radical to 7 forms the intermediate radical t-Bu-N=$C-C_6H_5$, which decomposes to give benzonitrile and t-butyl radical. The t-butyl radical generated from the ${\beta}$-cleavage adds to 7 giving the radical t-Bu-N=C-Bu-t, which cleaves only to pivalonitrile and t-butyl radical, inducing radical chain isomerization. Trimethylsilyl radical adds to 7 to give the intermediate t-Bu-N=$C-Si(CH_3)_3$, which collapses to $(CH_3)_3$SiCN and a t-butyl radical.

• Polymer(Korea)
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• v.36 no.1
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• pp.111-116
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• 2012

A functionalization of mesoporous materials with organosilane was carried out via a post-synthesis grafting method and $(n-BuCp)_2ZrCl_2$/methylaluminoxane (MAO) as subsequently immobilized on the functionalized mesoporous materials for ethylene polymerization. Organosilanes having amine, cyano or imidazoline group such as $N$-[(3-trimethoxysilyl)propyl]ethylenediamine (2NS), 4-(triethoxysilyl)butyronitrile (1NCy), 1-(3-triethoxysilylpropyl)-2-imidazoline (2NIm) were used for the surface functionalization of mesoporous materials. In the SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ catalyst preparation, the amount of MAO in feed increased with an decrease in the Zr content of the supported catalyst, and Al content in the supported catalyst increased. The ethylene homopolymerization activity of SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ dramatically increased as the amount of MAO in feed increased. Furthermore, when the immobilization time was 6 hrs, SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ showed the highest activity. The activities of supported 2NS-, 1NCy-, 2NIm-functionalized catalysts decreased in the following order, SBA-15/2NS/ > SBA-15/2NIm/ > SBA-15/1NCy/$(n-BuCp)_2ZrCl_2$. 2NS and 2NIm which have two amine groups per silane molecule were shown to interact with $(n-BuCp)_2ZrCl_2$ strongly compared to 1NCy which has one amine group. Thus, the activities increased with an increase in the nitrogen and the Zr content of the supported catalysts.

• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.299-307
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• 2021

Accumulation of amyloid beta (Aβ) and oxidative stress are the most common reason of Alzheimer's disease (AD). In the present study, we investigated the cognitive improvement effects of butanol (BuOH) fraction from Momordica charantia in Aβ_25-35-induced AD mouse model. To develop an AD mouse model, mice were received injection of Aβ_25-35, and then orally administered BuOH fraction from M. charantia at doses of 100 and 200 mg/kg/day during 14 days. In the T-maze and novel object recognition test, administration of BuOH fraction from M. charantia L. at doses of 100 and 200 mg/kg/day improved spatial ability and novel object recognition by increased explorations of novel route and new object. In addition, BuOH fraction of M. charantia-administered groups improved learning and memory abilities by decreased time to reach hidden platform in Morris water maze test. Oral administration of BuOH fraction from M. charantia significantly inhibited lipid peroxidation and nitric oxide levels in the brain, liver, and kidney compared with Aβ_25-35-induced control group. These results indicated that BuOH fraction of M. charantia improved Aβ_25-35-induced cognitive impairment by attenuating oxidative stress. Therefore, M. charantia could be useful for protection from Aβ_25-35-induced cognitive impairment.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.470-470
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• 2006

• Korean Journal of Crystallography
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• v.12 no.1
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• pp.10-13
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• 2001

Compound PdCl₂(PhCN)₂(1) reacted with tert-butylamine(t-BuNH₂) to give trans-[PdCl₂(t-BuNH₂)₂] (2) Compound 2 was characterized by spectroscopy (¹H-NMR, /sup 13/C{¹H}-NMR, and IR) and X-ray diffraction. Crystallographic data for f2: monoclinic space group p2₁/c, a=6.298(1)Å, b=20.740(2)Å, c=10.731(1)Å, β=92.58(1)°, Z=4, R(wR₂)=0.0207(0.0543).

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1251-1252
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• 2004

• YAKHAK HOEJI
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• v.27 no.4
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• pp.263-270
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• 1983

Effective BuOH fraction was extracted from Puerariae radix (Pueraria thunbergiana), and several pharmacological activities were examined. From several pharmacological examinations, it was found that BuOH fraction has an antipyretic activity against typhoid vaccine pyrexia in rabbit, a papaverine-like antispasmodic activity on isolated ileum and jejunum of rat, an analgesic effects on mice treated by 0.7% HAc, and an anti-inflammatory activity of carrageenin edema in rat. It was found that BuOH fraction has detoxication effects on acute and subacute toxic rat induced by alcohol in consequence of biochemical tests of serum. Therefore it was considered that BuOH fraction has preventive and therapeutic effects in alcohol intoxication.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.926-936
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• 2003

Overexpression of human Bcl-2 protein in recombinant Chinese hamster ovary (rCHO) cells producing humanized antibody (SH2-0.32) considerably suppressed sodium butyrate (NaBu)-induced apoptosis during batch culture by using commercially available serum-free medium, which extended the culture longevity. Due to the extended culture longevity provided by the anti-apoptotic effect of Bcl-2 overexpression, the final antibody concentration of 14C6-bcl-2 culture (Bcl-2 high producer, $23\;\mu\textrm{g}\;ml^{-1}$) was 2 times higher than that of the $SH2-0.32-{\Delta}bcl-2$ culture (cells transfected with bcl-2-deficient plasmid, $10.5\;\mu\textrm{g}\;ml^{-1}$) in the presence of NaBu. To determine the effect of NaBu/Bcl-2 overexpression on the molecular integrity of protein products, antibodies purified from 14C6-bcl-2 and $SH2-0.32-{\Delta}bcl-2$ cultures in the presence of NaBu were characterized by using various molecular assay systems. For comparison, antibody purified from the parental rCHO cell culture (SH2-0.32) in the absence of NaBu was also characterized. No significant changes in molecular weight of antibodies could be observed by SDS-PAGE. From GlycoSep-N column analysis, it was found that the core oligosaccharide structure ($GlcNAc_2Man_3GlcNAc_2$) was not affected by NaBu/Bcl-2 overexpression, while the microheterogeneity of N-linked oligosaccharide structure was slightly affected. Compared with the antibody produced in the absence of NaBu, the proportion of neutral oligosaccharides was increased from 10% (14C6-bcl-2) to 16% ($SH2-0.32-{\Delta}bcl-2$) in the presence of NaBu, which was accompanied by the reduced proportion of acidic oligosaccharides, especially of monosialylated and disialylated forms. The changes in microheterogeneous oligoformal structures of antibody in turn affected the mobility of antibody isoforms in isoelectric focusing (IEF), resulting in the occurrence of some more basic antibody isoforms produced in the presence of NaBu. However, the antigen-antibody binding properties were not changed by alteration of glycosylation pattern. The competitive enzyme-linked immunosorbent assay (ELISA) showed that the antibody produced by NaBu/Bcl-2 overexpression maintained its antigen-antibody binding properties with binding affinity of about $2.5{\times}10^9{\;}M^{-1}$. Taken together, no significant effects of NaBu/Bcl-2 overexpression on the molecular integrity of antibodies, produced by using serum-free medium, could be observed by the molecular assay systems.