• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.135-143
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• 2021

Drug addiction influences most communities directly or indirectly. Increasing studies have reported the relationship between circadian-related genes and drug addiction. Per2 disrupted mice exhibited more vulnerable behavioral responses against some drugs including methamphetamine (METH). However, its roles and mechanisms are still not clear. Transcriptional profiling analysis in Per2 knockout (KO) mice may provide a valuable tool to identify potential genetic involvement and pathways in enhanced behavioral responses against drugs. To explore the potential genetic involvement, we examined common differentially expressed genes (DEGs) in the striatum of drug naïve Per2 KO/wild-type (WT) mice, and before/after METH treatment in Per2 KO mice, but not in WT mice. We selected 9 common DEGs (Ncald, Cpa6, Pklr, Ttc29, Cbr2, Egr2, Prg4, Lcn2, and Camsap2) based on literature research. Among the common DEGs, Ncald, Cpa6, Pklr, and Ttc29 showed higher expression levels in drug naïve Per2 KO mice than in WT mice, while they were downregulated in Per2 KO mice after METH treatment. In contrast, Cbr2, Egr2, Prg4, Lcn2, and Camsap2 exhibited lower expression levels in drug naïve Per2 KO mice than in WT mice, while they were upregulated after METH treatment in Per2 KO mice. qRT-PCR analyses validated the expression patterns of 9 target genes before/after METH treatment in Per2 KO and WT mice. Although further research is required to deeply understand the relationship and roles of the 9 target genes in drug addiction, the findings from the present study indicate that the target genes might play important roles in drug addiction.

• Journal of Photoscience
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• v.9 no.2
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• pp.353-355
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• 2002

We prepared 3-(1-hydroxyethyl)-bacteriopyrochlorophy11-a (3) possessing magnesium atom and phytyl ester from modification of natural bacteriochlorophyll(BChl)-a. A dichloromethane solution of (3$^1$R) and (3$^1$S)-3 was diluted with 100~1000 fold volume of cyclohexane to give new species absorbing near-infrared lights. The resulting Q, maximum of (3$^1$R)-3 was 860 nm and red-shifted by 2150 $cm^{-1}$ / from the monomeric. In the nonpolar organic solvent, epimeric (3$^1$S)-3 showed a 1ess red-shifted peak at 798 nm as well as a residual monomeric band. Such visible spectra indicated that 3 diastereose1ectively aggregated in cyclohexane to afford oligomers possessing a simi1ar supramolecular structure with chlorosomal aggregates of natural BChl-d, 7,8-dehydro-form of 3.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.24-30
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• 2009

본 연구에서는 기존에 널리 사용되어져 온 Wavier-Stokes 방정식을 풀이하는 전통적인 CFD 해석에서 벗어나 최근에 그 응용 분야를 넓혀가고 있는 LBM의 해석코드를 개발하고, 이를 이용하여 이차원 채널속에 놓여진 쇄기형 물체 주위의 유동특성을 조사하였다. D2Q9 격자계 및 Bhatnagar-Gross-Krook (LBGK) 모델을 채택하였으며, 수치해석 결과는 기존의 실험결과의 잘 일치하였다. 쇄기형 물체에서 와의 형성 및 방출 Reynolds 수 범위는 $32{\leq}Re{\leq}620$ 이며, 원형실린더에서 알려진 Karman 와열을 형성하는 주기적인 와방출은 대칭적인 와가 형성된 후 $Re{\geq}85$부터 시작되며 Reynolds 수의 증가에 따라 와 방출 주파수는 증가되었다.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.179-183
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• 2006

Surface roughness is present in most of the microfluidic devices due to the microfabrication techniques. This paper presents lattice Boltzmann method (LBM) results for laminar flow in a microchannel with surface roughness. The surface roughness is modeled by an array of rectangular modules placed on top and bottom side of a parallel-plate channel. In this study, LBGK D2Q9 code in lattice Boltzmann Method is used to simulate flow field for low Reynolds number in a micro-channel. The effects of relative surface roughness, roughness distribution, roughness size and the results are presented in the form of the product of friction factor and Reynolds number. Finally, a significant increase in Poiseuille number is detected as the surface roughness is considered, while the effect of roughness on the microflow field depends on the surface roughness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.889-895
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• 2008

In this paper a Fractional-N frequency synthesizer is designed for UHF RFID readers. It satisfies the ISO/IEC frequency band($860{\sim}960MHz$) and is also applicable to mobile RFID readers. A VCO is designed to operate at 1.8GHz band such that the LO pulling effect is minimized. The 900MHz differential I/Q LO signals are obtained by dividing the differential signal from an integrated 1.8GHz VCO. It is designed using a $0.18{\mu}m$ RF CMOS process. The measured results show that the designed circuit has a phase noise of -103dBc/Hz at 100KHz offset and consumes 9mA from a 1.8V supply. The channel switching time of $10{\mu}s$ over 5MHz transition have been achieved, and the chip size including PADs is $1.8{\times}0.99mm^2$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.347-353
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• 2018

In this paper, we studied a design method for a band-pass waveguide filter with a modified H-type resonant iris (RI) placed in a thin transverse wall of a rectangular waveguide. The horizontal straight gap at the center of a conventional H-shaped iris is modified to a U-shaped one to increase the equivalent capacitance, and the equivalent inductance is improved by changing the vertical two straight slots into C-shaped ones. From some simulation results for the frequency response of the proposed RI, it was observed that the proposed iris was advantageous for reducing its size and having better cutoff, compared to typical H-shaped one. Equivalent inductance, capacitance, and quality factor of the proposed RI were extracted to analyze its performance. A third-order band pass filter using the proposed modified H-shaped iris was designed and, it was observed that the filter operated in the frequency range of 9.18-9.84 GHz with its insertion loss of 0.3 dB and return loss of 14 dB.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.138-141
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• 2004

[ $MnO_2$ ]가 첨가된 $0.9Pb(Zr_{0.5}Ti_{0.5})O_3-0.2Pb[(Zn_{0.8}Ni_{0.2})_{1/3}Nb_{2/3}]O_3$(0.8PZT-0.2PZNN) 세라믹스는 그 압전특성과 유전특성이 뛰어나지만 $1000^{\circ}C$ 이하의 낮은 소결 온도에서는 소결되지 않는다. $1000^{\circ}C$이하의 낮은 소결온도에서 소결하기 위해 CuO를 첨가한 결과, 소결온도 $920^{\circ}C$에서 소결성은 우수하였으나 그 압전 특성의 저하가 두드러졌다. 이는 XRD에서 확인한 결과에 따르면 CuO의 첨가가 우수한 MPB 조성으로 판명된 $MnO_2$ 가 첨가된 0.8PZT-0.2PZNN 세라믹스의 결정구조를 Rhombohedral 구조로 바꾸기 때문인 것으로 보였으며 이러한 문제는 PZNN의 비율을 조절하여 0.875PZT-0.125PZNN 세라믹스를 선택함으로 인해 해결할 수 있었다. 그러나 여전히 낮은 $Q_m$값을 높이기 위해서 $Al_2O_3$를 첨가하였고 그 결과 시편의 tetragonality 감소와 $Q_m$값의 증가를 확인할 수 있었으나 그 첨가량이 0.2wt% 이상일 경우에는 밀도의 감소로 인한 압전특성의 저하가 나타났다. 밀도의 향상을 위해 Zn and Ni excess 조성을 선택하였고 그 결과 0.5wt% $MnO_2$와 0.2wt% CuO 그리고 0.3wt% $Al_2O_3$를 첨가한 0.875PZT-0.125PZNN 세라믹스(Zn and Ni excess 조성)를 $920^{\circ}C$에서 소결한 경우 $k_p=0.581,\;Q_m=809,\;d_{33}=345\;pC/N\;and\;{\varepsilon}_{33}/{\varepsilon}_0=1345$의 빼어난 압전 및 유전특성과 $330^{\circ}C$의 높은 $T_c$를 보였고 그 조성의 vibration velocity는 약4.5 m/s로 나타났다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1167-1172
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• 2013

This paper presents a X-band doppler radar with high conversion gain using a self-oscillating-mixer(SOM) that oscillation and frequency mixing is realized at the same time. To improve phase noise of the SOM oscillator, a ${\lambda}/2$ slotted square patch resonator(SSPR) was proposed, which shows high Q-factor of 175.4 and the 50 % reduced circuit area compared to the conventional resonator. To implement the low power system, low biasing voltage of 1.7 V was supplied. To enhance the conversion gain of the SOM, bias circuit is configured near the pinch-off region of transistor, and the conversion gain was optimized. The output power of the proposed SOM was -3.16 dBm at 10.65 GHz. A high conversion gain of 9.48 dB was obtained whereas DC Power consumption is relatively low about 7.65 mW. The phase noise is -90.91 dBc/Hz at 100 kHz offset. The figure-of-merit(FOM) of the proposed SOM was measured as -181.8 dBc/Hz, which is supplier to other SOMs by more than about 7 dB.

• ALGAE
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• v.22 no.2
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• pp.131-139
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• 2007

The expression of genes responding to cold stress in a freshwater alga, Spirogyra varians, was studied by using differential expression gene (DEG) method. A gene strongly up-regulated in 4°C was isolated and designated as SVCR2 (Spirogyra varians cold regulated) gene. The cDNA encoding SVCR2 was cloned using λZAP cDNA library of Spirogyra varians. The deduced amino acid had a sequence similarity with trans-membrane protein in Arabidopsis thaliana (Q9M2D2, 52.7%). Northern blot analysis demonstrated that transcript level of SVCR2 increased about 10 fold under low temperature (4°C), compared with that cultured at warm (20°C) conditions. The expression of SVCR2 was also affected by light conditions. When the plants were exposed to high light (HL) (1200 μmol photon m–2 s–1), the expression of SVCR2 began within 2 hrs. This gene expression lasted for 4 hrs and decreased afterwards. Under the blue light (470 nm) condition, the expression of this gene was induced in same way as HL treatment, even under less than 100 μmol photon m–2 s–1. But red light (650 nm) and UV-A irradiation did not affect the expression of SVCR2.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.82-88
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• 2005

3D QSAR studies for the fungicidal activities against resistive phytophthora blight (RPC; 95CC7303) and sensitive phytophthora blight (Phytopthora capsici) (SPC; 95CC7105) by a series of new 2-alkoxyphenyl-3-phenylthioisoindoline-1-one derivatives (X: A=propynyl & B=2-chloropropenyl) were studied using comparative molecular field analyses (CoMFA) methodology. The CoMFA models were generated from the two different alignment, atom based fit (AF) alignment and field fit (FF) alignment. The atom based alignment exhibited a higher statistical results than that of field fit alignment. The best models, A3 and A7 using combination fields of H-bond field, standard field, LUMO and HOMO molecular orbital field as additional descriptors were selected to improve the statistic of the present CoMFA models. The statistical results of the two models showed the best predictability of the fungicidal activities based on the cross-validated value $q^2\;(r^2_{cv.}=RPC:\;0.625\;&\;SPC:\;0.834)$, non cross-validated value $(r^2_{ncv.}=RPC:\;0.894\;&\;SPC:\;0.915)$ and PRESS value (RPC: 0.105 & SPC: 0.103), respectively. Based on the findings, the predictive ability and fitness of the model for SPC was better than that of the model for RPC. The fugicidal activities exhibited a strong correlation with steric $(66.8{\sim}82.8%)$, electrostatic $(10.3{\sim}4.6%)$ and molecular orbital field (SPC: HOMO, 12.6% and RPC: LUMO, 22.9%) factors of the molecules. The novel selective character for fungicidal activity between two fungi depend on the positive charge of ortho, meta-positions on the N-phenyl ring and size of hydrophilicity of a substituents on the S-phenyl ring.