• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.11
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• pp.62-71
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• 2002

This paper presents new DSP (Digital Signal Processor) instructions and their hardware architecture for high-speed FFT. the instructions perform new operation flows, which are different from the MAC (Multiply and Accumulate) operation on which existing DSP chips heavily depend. The proposed DPU (Data Processing Unit) supporting the instructions shows two times faster than existing DSP chips for FFT. The architecture has been modeled by the Verilog HDL and logic synthesis has been performed using the 0.35 ${\mu}m$ standard cell library. The maximum operating clock frequency is about 144.5 MHz.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.599-607
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• 2009

A series of conjugated cyclic and linear enkephalin analogs, Tyr-c[D-A2bu-Gly-Phe-Asp(NH-X)], where X = methyl, stearyl or$ PEG_350$, and Tyr-D-Ala-Gly-Phe-Cys(S-X), where X = methyl, octyl, or farnesyl, were synthesized in solution to investigate the receptor selectivity of opioids based on Schwyzer's membrane compartment $concepts.^{5,6}$ Cyclizations of the target compounds were achieved in high yields (> 60%) employing BOP, $NaHCO_3$ in DMF despite the steric hindrance of the bulky pendant groups. In the binding assay, the hydrophobic fatty acyl conjugates retained $\mu$-receptor selectivity. The unsaturated farnesyl conjugate exhibited the increased binding affinity than the saturated stearyl conjugate for both $\mu$-and $\delta$-opioid receptors. The PEG conjugates displayed the $\delta$-receptor selectivity. The low molecular weight $PEG_350$ conjugate exhibited the increase selectivity than the high molecular weight $PEG_5000$ conjugate to the $\delta$-receptor. The results of this study support the membrane compartment concepts.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.566-575
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• 2008

We investigated the field emission characteristics from the planar field emitters made of double-walled carbon nanotubes (DWCNTs) synthesized by a catalytic chemical vapor deposition (CCVD) method. Transmission electron microscopy, Thermogravimetric and Raman analysis showed that the carbon materials have a low defect level in their atomic carbon structure, pointing to the synthesis of high-purity DWCNTs. For field emission properties of DWCNTs, the turn-on field of DWCNTs was $1.9\;V/{\mu}m$ and the current density was about $74\;mA/cm^2$ at $8.1\;V/{\mu}m$, which is sufficient for the applications of field emission displays and vacuum microelectronic devices. The DWCNT field emitters also exhibited a uniform field emission pattern and good field emission stability in a diode configuration.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.427-435
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• 1994

Cu-metallized low firing temperature substrates were synthesized by cofiring green sheet of cordierite-based glass with Cu. By Sol-Gel method, Cu powder was coated with borosilicate gel which should act as a glass frit in Cu paste during cofiring. Theoretical weight ratios of Glass/Cu were controlled to be 2.5, 5, 10 and 15% by varying alkoxide concentrations. Average particle size of coated Cu was 0.629~0.674 ${\mu}{\textrm}{m}$ in comparison to that of as-received Cu(0.596 ${\mu}{\textrm}{m}$), which increased with alkoxide concentration but did not increase above certain concentration. The weight ratios of coated layer were 2.11~5.37%. The properties of Cu-metallized low firing temperature substrate, cofired at 90$0^{\circ}C$ for 1h under H2/N2 atmosphere, were as follows; sheet resistance was 13~43 m{{{{ OMEGA }}/$\square$, adhesion strength was 1.0~2.1 kgf/$\textrm{mm}^2$. From the observations of SEM photographs, the gel coated on Cu performed excellently as a glass frit.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.395-398
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• 1992

In order to study the influence of a 6'-methyl group in ring C of griseofulvin ${\underline{(1)}}$ on the fungicidal activity, 6'-methyl group was replaced with a larger phenyl group as $({\pm})-6'-phenylgriseofulvin$ ${\underline{(3)}}$, $({\pm})-6'-epiphenylgriseofulvin$ ${\underline{(4)}}$, synthesized by a Diels-Alder cycloaddition. Their biological activities were examined against Botrytis allii (IFO 9430) and B. cinerea (AHU 9573). $({\pm})-6'-Phenylgriseofulvin $ ${\underline{(3)}}$ showed high activity in $25\;{\mu}g/disc$.

• YAKHAK HOEJI
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• v.50 no.4
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• pp.278-286
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• 2006

Classical dihydropyrrole[3,4-f]quinazoline antifolates 7,8 and 9, in which the tricyclic ring is structurally similar to the pteridine ring of $CH_2-THF(1)$, the cofactor of thymidylate synthase (TS), were synthesized, and their in vitro antitumor activity was evaluated by measuring the cell growth inhibitory activity against cancer cell lines. The target compounds were cytotoxic against CCRF-CEM, human T-cell acute lymphoblastic leukemia, with the cell growth inhibitory activity $(IC_{50})$ of $0.8{\sim}8.3\;{\mu}M$. Among the three compounds, 3-amino analog 7 was 10- and 3.5-fold more cytotoxic compared to the 3-methyl analogs 8 and 9, and its cytotoxicity was similar to that of the reference compound with the $IC_{50}$ value of $0.83\;{\mu}M$. This result was supposed as the consequence of the fact that dihydropyrroloquinazolinone ring with amino group was able to bind well in the active site of TS. In the case of 3-methyl analogs, analog 9, which has two-carbon bridge between the dihydropyrroloquinazolinone ring and benzoyl-L-glutamic acid, was 3-times more potent in cytotoxicity than analog 8 which has one-carbon bridge, and this result indicates that the distance and conformational orientation of the benzoyl-L-glutamic acid moiety with respect to the tricyclic ring may also be a crucial determinant of cell growth inhibitory activity.

• Bulletin of the Korean Chemical Society
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• v.21 no.1
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• pp.65-68
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• 2000

A $\mu-oxo$ diiron(III) complex and two bis( $\mu-alkoxo)$ diiron(III) complexes with biomimetic tripodal ligand containing mixed N/O donor atoms were synthesized using a mononuclear iron(III) complex as starting material. Depending on the amounts and kinds of bases used, we obtained various kinds of diiron (III) complexes. The reaction of $[$Fe^{III}$(Hbbea)Cl_2]Cl$, 1, with an equivalent amount of $KO_2$ or NaOAc produced $[$Fe^{III}$_2O(Hb-bea)_2Cl_2]Cl_2$, 2. An additional equivalent amount of NaOBz or NaOAc converts complex 2 to complex 3 or complex 4 depending on the base used. The addition of two equivalent amounts of NaOBz orNaOAc directly converts complex 1 to $[$Fe^{III}$_2(bbea)_2(OBz)_2]Cl_2$, 3, or $[$Fe^{III}$_2(bbea)_2(OAc)_2]Cl_2$, 4, depending on the base used. Crystal data are as follows: [$Fe^{III}_2O(Hbbea)_2Cl_2]Cl_2$, 2: monoclinic space group $$P2_1/n$$, a = 8.421 (1) $\AA$, b = 18.416 (2) $\AA$, c = 13.736 (1) $\AA$, $\beta$ = 104.870 $(7)^{\circ}$, V = 2058.9 (4) $\AA^3$, Z = 2, R1 = 0.0469 and wR2 = 0.1201 for reflections with I > 2 ${\sigma}$(I).

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.1
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• pp.149-157
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• 2010

목적 : 월견초는 다량의 불포화 지방산인 리놀렌산과 감마 리놀렌산을 함유하고 있으며, 천식성 기침이나 아토피피부염에 효능이 있는 것으로 알려져 있다. 본 연구는 월견초의 전초와 종자 추출물의 피부 멜라닌 합성에 대한 억제 효과를 조사하였다. 방법 : B16F10 멜라닌세포주를 이용하여 멜라닌, tyrosinase 활성 및 세포생존율을 측정하였다. 또한 멜라닌 합성- 관련효소인 tyrosinase, TRP-1, TRP-2의 단백질발현과 $\alpha$-MSH를 처리하여 색소침착을 유도 한 뒤 단백질 발현을 조사하였다. 결과 : 월견자는 B16F10 세포의 멜라닌 합성을 $5\;{\mu}g/ml$와 $10\;{\mu}g/ml$ 농도에서 각각 대조군의 81.3%, 68.3%로 억제하였고 tyrosinase의 활성도 이와 유사하게 억제하였다. 멜라닌 합성-관련효소들의 단백질발현을 관찰한 결과 월견초와 월견자는 tyrosinase 발현을 억제하였으며 TRP-1과 TRP-2의 발현에는 영향을 주지 않았다. 특히 $\alpha$-MSH에 의한 과색소 유도 시 tyrosinase 발현이 현저하게 감소되었으며, 월견자의 멜라닌 합성 억제 효과가 월견초 보다 높게 나타났다. 결론 : 이상의 연구 결과 월견자는 멜라닌세포의 tyrosinase 단백질 발현과 tyrosinase 활성을 억제하여 멜라닌 생성을 감소시키는 것으로 사료된다.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.130-136
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• 1999

Mouse guanylate-binding protein 3 (mGBP3) is a 71-kDa GTPase which belongs to GTP-binding protein family. The present study showed that the expression of mGBP3 transcript was readily induced in a dose dependent fashion in the macrophage cell line RAW264.7 treated with either $interferon-{\gamma} (IFN-\gamma)$ or lipopolysaccaride (LPS). The expression of mGBP3 protein was also apparent by 4 and 6 h after the treatment of cells with IFN-\gamma (100 U/ml) or LPS ($1{\mu}g/ml$) , and remained at palteau for at least 24 h. Cycloheximide ($10{\mu}g/ml$) had no effect on the $IFN-\gamma-$ or LPS-induced mGBP3 expression, suggesting that the mGBP3 induction did not require further protein synthesis. Interestingly, a protein kinase C (PKC) inhibitor staurosporine (50 nM) abolished the induction of mGBP3 expression by LPS, but not by $IFN-{\gamma}$. These findings suggest that mGBP3 may be involved in the macrophage activation process and both IFN-\gamma and LS induce the mGBP3 expression through distinct signal transduction pathways.

• Journal of Surface Science and Engineering
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• v.34 no.5
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• pp.421-428
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• 2001

New WC-CrN superlattice film was deposited on Si substrate (500$\mu\textrm{m}$) using cathodic arc ion plating system. The microstructure and mechanical properties of the film depend on the superlattice period (λ). In the X-ray diffraction analysis (XRD), preferred orientation of microstructure was changed according to various superlattice periods(λ). During the Transmission Electron Microscope analysis (TEM), microstructure and superlattice period (λ) of the WC - CrN superlattice film was confirmed. Hardness and adhesion of the deposited film was evaluated by nanoindentation test and scratch test, respectively. As a result of nanoindentation test, the hardness of WC - CrN superlattice film was gained about 40GPa at superlattice period (λ) with 7nm. Also residual stress with various superlattice period (λ) was measured on Si wafer (100$\mu\textrm{m}$) by conventional beam-bending technique. The residual stress of the film was reduced to a value of 0.2 GPa by introducing Ti - WC buffer layers periodically with a thickness ratio ($t_{buffer}$/$t_{buffer+superlattice}$ ). To the end, for the evaluation of oxidation resistance at the elevated temperature, CrN single layer and WC - CrN superlattice films with various superlattice periods on SKD61 substrate was measured and compared with the oxidation resistance.