• Journal of the Korean Chemical Society
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• v.19 no.2
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• pp.130-133
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• 1975

The 4'-thio analogs of the 5-bromo-and 5-iodo-pyrimidine nucleosides were prepared by condensation of 2,3,5-tri-O-acetyl-4-thio-${\alpha},{\beta}$-D-ribofuranosyl chloride with the chloromercury derivatives of 5-halogeno-2,4-bis(trimethylsiloxy)pyrimidine, followed by the removal of the protecting groups. Although the biological activities of the 4'-thio derivatives are not greatly different from the corresponding 4'-oxygen analogs in this preliminary test, the fact that the 4'-thio analogs have comparableihigh activities, is of interest, and indicates the value of further biochemical examinations.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.413-417
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• 2018

The $Li_4Ti_5O_{12}$ of anode material for the hybrid capacitor was coated using $CePO_4$, $M_3(PO_4)_2$ (M=Mg, Zn). The capacitance of phosphate coated $Li_4Ti_5O_{12}$ was found to be lower than that of $Li_4Ti_5O_{12}$, whereas the equivalent series resistance was higher than that of $Li_4Ti_5O_{12}$. With an increase in cycle number, the base of cylindrical cell exhibited swelling due to gas generated from the reaction between $Li_4Ti_5O_{12}$ and electrolyte. The swelling cycle number of phosphate coated $Li_4Ti_5O_{12}$ was higher than that of $Li_4Ti_5O_{12}$ due to improvement in electrochemical stability. Based on the results, it is proposed that phosphate coating can be employed as a barrier layer to control the gassing reaction by isolating the $Li_4Ti_5O_{12}$ particle from electrolyte solution.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.77-80
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• 2001

이동통신시장 및 IT 시장의 급성장, Mobile 인터넷 기술의 발전 그리고 4S 관련 기술의 발전에 힘입어 국내에서도 LBS 관련 산업이 활성화되고 있다. 이에 본 연구에서는 이러한 LBS 를 효율적으로 지원하기 위하여 기본적으로 요구되는 4S 기술의 개념적 정의를 살펴보고, 특히 LBS 사업에 직간접 적으로 필요한 4S관련 기반구축연구 및 4S 핵심기술개발에 대하여 소개하고 있다. 4S 핵심기술개발 분야에서는 우선적으로 LBS 의 기반 기술이 되는 4S 핵심기술 및 상호연계 기술[3], 4S-Mobile 관련 기술 그리고 4S-VAN 관련 기술 개발 사항에 대하여 중점적으로 살펴보며, 4S 관련 기반구축연구분야에서는 LBS 산업을 활성화하고자 할 때 문제 될 수 있는 4S 및 LBS 관련 표준화 작업, 법 및 제도연구 그리고 감리지침 모델 도출에 대하여 중점적으로 살펴보고자 한다. 끝으로 이러한 4S 기반 프레임워크 구축이 향후 LBS 와 4S 산업에 어떠한 영향을 미치는지에 대하여 살펴본다.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.175-182
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• 2005

This paper presents encryption techniques for digital right management solutions of MPEG-4 streams. MPEG-4 is a format for multimedia streaming and stored in the MPEG-4 file format. We designed three kinds of encryption methods, which encrypt macro blocks (MBs) or motion vectors (MVs) of I-, P-VOPs (Video Object Planes), extracted from the MPEG-4 file format. We used DES to encrypt MPEG-4 data Based on theses three methods, we designed and implemented a DRM solution for an Internet broadcasting service, which enabled a MPEG-4 data streaming, and then compared the results of decryption speed and quality of rendered video sequences to get an optimal encryption method.

• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.519-524
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• 2003

During the period of co-existence of IPv4 and IPv6, Ipv6 over IPv4 tunneling technique is intended as a start-up transition mechanism. However, most of IPv4 firewalls do not support the IPv6 over IPv4 tunneling packet filtering. Finally, it is impossible that a user inside IPv4 firewall connects with an IPv6 host across IPv4 network. Without any additional hardware or changing the policy of IPv4 firewall, we solve this problem using proposed Double-encapsulation and applied-HTTP tunneling technique that are end-to-end solutions. This enables cheaper IPv6 migration solutions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.342-343
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• 2005

In this study,. the microwave dielectric properties of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics with sintering temperature were investigated for LTCC application. According to the X-ray diffraction patterns, the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics had columbite structure of the $TiTe_3O_8$ phase and scheelite structure of the $CaWO_4$ phase. Increasing the sintering temperature, the bulk density, the dielectric constant and the quality factor of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics were increased. In the case of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics sintered at $810^{\circ}C$, the bulk density, the dielectric constant and the quality factor were 5.72$g/cm^2$, 33.6, 22,013GHz respectively.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.316-321
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• 2008

Monodispersed particles of poly(styrene-co-4-vinylpyridine), poly(st-co-4vp) were prepared by soapless emulsion polymerization. Iron oxide was formed on the surface and inside of the poly(st-co-4vp) particles by thermal decompostion of iron pentacarbonyl. The obtained magnetic poly(st-co-4vp) particles was mondispersed and the average size was 250 nm. The magnetic poly(st-co-4vp) particles had 14% of iron oxide, which was identified as $Fe_3O_4$ by XRD. The magnetic poly(st-co-4vp) particles had superparamagnetism according to superconducting susceptometer (SQUID).

• YAKHAK HOEJI
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• v.50 no.6
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• pp.403-408
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• 2006

1-Amino-5,6-dimethoxyindan hydrochloride was synthesized from 3- (3,4-dirnethoxyphenyl)propionic acid by intramolecular Friedel-Crafts acylation, oximation with hydroxylamine, and reduction with an overall yield of 74%. 2-Amino-5,6-dimethoxyindan hydrochloride was synthesized from 3-(3,4-dirnethoxyphenyl)propionic acid by intramolecular Friedel-Crafts acylation, oximation with isoamylnitrite, reduction in NaOH and reaction with HCI to form 5,6-dimethoxy-2-indanone, which was reacted with hydroxylamine and reduced with an overall yield of 42%. 5,6-Dimethoxyindan-1,2-dione-2-oxime, which was catalytically hydrogenated to afford cis-, and trans-1-amino-5,6-dimethoxyindan-1-ol as 3 : 1 ratio. This mixture was treated with Li and reacted with chloroacetyl chloride. Cis isomer was acylated and cyclized to synthesize rir -( ${\pm}$ )-7,8-dimethoxy-4,4a,5,9b-tetrahydroindeno[1,2-b][1,4]oxazin-3(2H)-one, but trans isomer was just acylated to form amide.

• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.154-165
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• 2021

This study aimed to investigate whether the antidiabetic drugs dipeptidyl peptidase 4 (DPP4) inhibitors such as evogliptin and sitagliptin affect the membrane DPP4 (mDPP4) enzymatic activity and immune function of T helper1 (Th1) cells in terms of cytokine expression and cell profiles. The mDPP4 enzymatic activity, cytokine expression, and cell profiles, including cell counts, cell viability, DNA synthesis, and apoptosis, were measured in pokeweed mitogen (PWM)-activated CD4+CD26+ H9 Th1 cells with or without the DPP4 inhibitors, evogliptin and sitagliptin. PWM treatment alone strongly stimulated the expression of mDPP4 and cytokines such as interleukin (IL)-2, IL-10, tumor necrosis factor-alpha, interferon-gamma, IL-13, and granulocyte-macrophage colony stimulating factor in the CD4+CD26+ H9 Th1 cells. Evogliptin or sitagliptin treatment potently inhibited mDPP4 activity in a dose-dependent manner but did not affect either the cytokine profile or cell viability in PWM-activated CD4+CD26+ H9 Th1 cells. These results suggest that, following immune stimulation, Th1 cell signaling pathways for cytokine expression function normally after treatment with evogliptin or sitagliptin, which efficiently inhibit mDPP4 enzymatic activity in Th1 cells.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.307-313
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• 2021

Traf4 (Tumor necrosis factor Receptor Associated Factor 4) is a member of the tumor necrosis factor receptor (TNFR) - associated factors (TRAFs) family. TRAF4 is overexpressed in tumor cells such as breast cancer and associated with cytoskeleton and membrane fraction. Interestingly, TRAF4 was localized with tight junctions (TJs) proteins including OCLN and TJP1 in mammary epithelial cells. However, the expression patterns and biological function of Traf4 were not examined in preimplantation mouse embryos although Traf4-deficient mouse showed embryonic lethality or various dramatic malformation. In this study, we examined the temporal and spatial expression patterns of mouse Traf4 during preimplantation development by qRT-PCR and immunostaining, and its biological function by using siRNA injection. We found upregulation of Traf4 from the 8-cell stage onwards and apical region of cell - cell contact sites at morula and blastocyst embryos. Moreover, Traf4 knockdown led to defective TJs without alteration of genes associated with TJ assembly but elevated p21 expression at the KD morula. Taken together, Traf4 is required for TJs assembly and cell proliferation during morula to blastocyst transition.