• Journal of Pharmaceutical Investigation
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• 제18권3호
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• pp.139-144
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• 1988

Piperacillin phthalidyl ester was synthesized by reacting piperacillin with triethylamine and bromophthalide in acetone and its chemical structure was determined by UV, IR, and PMR. The partition coefficient of the ester was increased and the ester was more lipophilic and less water soluble than piperacillin. The ester did not show the antimicrobial activity against Bacillus subtilis ATCC 6633 in vitro, but when hydrolyzed, the parent drug of ester, piperacillin, revealed antimicrobial activity in vivo. After a single oral dose of both piperacillin and the ester to rabbits, the serum piperacillin concentration was measured by bioassay. The ester exhibited improved pharmatokinetic characteristics: $T_{max}\;of\;2hr,\;C_{max}\;of\;4.26{\mu}g{\cdot}ml^{-1},K_{el}\;of\;0.057hr^{-1},\;and\;total\;AUC\;of\;85.42{\mu}g{\cdot}hr{\cdot}ml^{-1}$. Piperacillin on the other hand, did not exhibit any gastro-intestinal absorption.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제24권9A호
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• pp.1442-1450
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• 1999

In this paper, we present an efficient hardware architecture for the frame memory of the MPEG-2 video encoder. Both the total size of internal buffers and the number of logic gates are reduced by the proposed memory map which can provide an effective interface between MPEG-2 video encoder and the external DRAM. Furthermore, the proposed scheme can reduce the DRAM access time. To realize the frame memory hardware,$0.5\mu\textrm{m}$, VTI, vemn5a3 standard cell library is used. VHDL simulator and logic synthesis tool are used for hardware design and RTL (register transfer level) function verification. The frame memory hardware emulator of the proposed architecture is designed for gate-level function verification. It is expected that the proposed frame memory hardware using VHDL can achieve suitable performance for MPEG-2 MP@ML.

• YAKHAK HOEJI
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• 제53권1호
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• pp.41-44
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• 2009

A series of 2-alkyl-2,3-dihydro-1H-2-azacyclopenta[b]anthracene-5,10-diones ($3a{\sim}h$) were synthesized and evaluated in vitro cytotoxicity against colon cancer cell lines (HCT116 and SW620) and nuroblastoma cell lines (SK-N-SH and SK-N-MC). Among them, compound 3f showed significant cytotoxic activity ($IC_{50}$ against SK-N-SH; $14.8{\mu}M$, $IC_{50}$ against SK-N-MC; $11.3{\mu}M$).

• Elastomers and Composites
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• 제35권4호
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• pp.281-287
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• 2000

Waterborne polyurethane(PU) microgel dispersions were synthesized with different mole ratio of polytetramethylene glycol(PTMG) to dimethylol propionic acid(DMPA). Particle size distribution, thermal and mechanical properties of the PU microgels were investigated. Particle size of the microgels was distributed in the range of $98{\sim}$680{\mu}m$ and decreased with increasing the mole ratio of DMPA and 1,2,6-hexanetriol. Glass transition temperature and melting temperature of the microgels were in the range of $-79.7 {\sim}-78.1^{\circ}C$, $22{\sim}24^{\circ}C$ respectively. Tensile strength and elongation of the PU microgel films were maximum in the case of 60/40 mole ratio of PTMG/DMPA.

• Tribology and Lubricants
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• 제13권4호
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• pp.60-65
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• 1997

The tungsten disulfide $(WS_2)$ solid lubricant was synthesized by two different reaction processes, i.e., the reaction between $CS_2$ gas phase and solid $WO_3$powder, and the vapour phase transport method of tungsten and sulfur in a high vacuum. The chemical and physical characteristics of synthesized $WS_2$powder were analyzed in terms of the average particle size, morphology, crystalline phase etc. in comparison with those of commercial $WS_2$powder. The solid $WO_3$ powder with the average size of 0.2 ${\mu}{\textrm}{m}$ was reacted with $CS_2$gas flowed with$N_2$or 96%$N_2{\times}4%H_2$forming gas for 36 h and 24 h at 90$0^{\circ}C$ respectively. $WS_2$ crystalline phase was then formed through the intermediate phase of .$W_{20}O_{58}$ In the case of vapour phase transport method, the 3.5 wt% iodine was added as a vapour transport reagent into the composition of tungsten and sulfur powders maintaining a constant molar ratio of W:S=1:2.2. The mixture was then heat treated at 85$0^{\circ}C$ for 2 weeks in vacuum. The reaction product obtained showed the average size of 12 ${\mu}{\textrm}{m}$ and the hexagonal plate shape of typical solid lubricant with 2H-$WS_2$crystalline phase.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제7권2호
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• pp.292-300
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• 1997

PSZT powders having the particle size of 0.5~5 $\mu\textrm{m}$ with cubic shapes, were prepared by a hydrothermal reaction in the temperature range of 150~$^{\190circ}C$ for a 2 h reaction. Experimental results showed that as the reaction temperature increased, the nucleation and crystal growth were accelerated and the the particle size became larger. However, the particle size became smaller with its narrow distribution as the concentration of a mineralizer (KOH) increased. It was possible to reduce the reaction temperature by increasing mineralizer concentrations. With increase in Zr/Ti ratio, the major crystal phase of synthetic PSZT powders was seen to change from tetragonal phase to rhombohedral phase.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
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• pp.351-360
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• 1999

A large NaX type zeolite crystal of a uniform particle size of 20${\mu}{\textrm}{m}$ are grown with various H2O content by hydrothermal reaction and added seed crystal (2~3 ${\mu}{\textrm}{m}$) to reactant solution as a function of different adding seed levels from 3 to 15 %. The result that increased purity of NaX zeolite above 95% and homogeneity of crystal size by increasing adding seed levels, also decreased crystallization time. It was explained that adding seed to synthesis solution leaded out increase of surface area of physical contact reaction and directed growth of seed crystal, so more rapid consumption of reaction gel as increase seeding levels.

• Journal of the Korean Chemical Society
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• 제31권5호
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• pp.434-443
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• 1987

The formation constants of the complexes between Ln-EDTA 1 : 1 complex and IMDA have been investigated by a potentiometric titration method at 20.0${\pm}$0.2 degree C and ${\mu}$ = 0.1 (KNO$_3$). Unusually large stability in Ln(EDTA) mixed ligand complexes was found. Trends in the formation constants vs. atomic number of the lanthanide metals were discussed on the basis of coordination number and ionic radius of the metals.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1965-1969
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• 2014

A new tetranuclear Mn(III) complex $[Mn^{III}{_4}(sae)_4({\mu}_3-O)({\mu}_{1,1}-N_3)(OH)(H_2O)_2]{\cdot}H_2O$ (1) ($H_2sae$ = 2-salicylideneamino-1-ethanol) has been synthesized by the reaction of $MnCl_2{\cdot}4H_2O$, $H_2sae$ and sodium azide in the mixed solvent of methanol, acetonitrile and water. The X-ray diffraction analysis shows that the four Mn(III) ions in complex 1 have a unique adamantine arrangement, whereas the coordination environment of each Mn(III) ions is different. Magnetic studies indicate that complex 1 manifests antiferromagnetic behaviors. The magnetic susceptibilities of complex 1 have been fitted by two magnetic models based on the suitable analysis of its magnetic structural topology.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.147-152
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• 1998

Cinnamaldehydes and related compounds were synthesized from various cinnamic acids based on the $2^{I}$-hydroxycinnamaidehyde isolated from the bark of Cinnamomum cassia Blume. The cytotoxicity to human solid tumor cells such as A549, SK-OV-3, SK-MEL-2, XF498 and HCT15 were measured. Cinnamic acid, cinnamates and cinnamyl alcohols did not show any cytotoxicity against the human tumor cells. Cinnamaldehydes and realted compounds were resistant to A549 cell line up to 15 .mu.g/ml. In contrast, HCT15 and SK-MEL-2 cells were much sensitive to these cinnamaidehyde analogues which showed $ED{50} values 0.63-8.1{\mu}g/ml.$Cytotoxicity of the saturated aldehydes was much weak compared to their unsaturated aldehydes. From these studies, it was found that the key functional group of the cinnamaldehyde-related compounds in the antitumor activity is the propenal group.p.