• Molecules and Cells
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• v.25 no.4
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• pp.559-565
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• 2008

Members of the TGA family of basic domain/leucine zipper transcription factors regulate defense genes through physical interaction with NON-EXPRESSOR OF PR1 (NPR1). Of the seven TGA family members, TGA4/octopine synthase (ocs)-element-binding factor 4 (OBF4) is the least understood. Here we present evidence for a novel function of OBF4 as a regulator of flowering. We identified CONSTANS (CO), a positive regulator of floral induction, as an OBF4-interacting protein, in a yeast two-hybrid library screen. OBF4 interacts with the B-box region of CO. The abundance of OBF4 mRNA cycles with a 24 h rhythm under both long-day (LD) and short-day (SD) conditions, with significantly higher levels during the night than during the day. Electrophoretic mobility shift assays revealed that OBF4 binds to the promoter of the FLOWERING LOCUS T (FT) gene, a direct target of CO. We also found that, like CO and FT, an OBF4:GUS construct was prominently expressed in the vascular tissues of leaf, indicating that OBF4 can regulate FT expression through the formation of a protein complex with CO. Taken together, our results suggest that OBF4 may act as a link between defense responses and flowering.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1165-1171
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• 2008

In this paper, a pilot emitting amplify-and-forward relay and its beamforming schemes, OBF (overall beamforming) and RBF (hop-by-hop beamforming), are proposed for two-hop relaying systems. The OBF performs beamforming with respect to a overall channel from a source node (SN) to a destination node (DN) through a relay node (RN), while the proposed RBF performs two independent beamformings: from the SN to the RN and from the RN to the DN. From our analytic and numerical results, it is shown that bit-error-rate (BER) performance of the proposed RBF is better than that of the OBF scheme since the RBF system can estimate channel more proper than the CBF system, which is verified by deriving and comparing the mean square errors of the channel estimation.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.255-259
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• 2015

We have proposed and experimentally verified a pulse-width modulation (PWM) generator which directly generated a PWM signal in the optical domain. Output waveforms were clear at the repetition rate of 16 MHz; the duty cycle (DC) was from 14.7% to 72.1%; and the DC-control resolution was about 4.399%/dB. The PWM generator' operation principle is based on the injection-locking property of a single-mode Fabry-$P{\acute{e}}rot$ laser diode (SMFP-LD). The SMFP-LD, which has a self-locked mode wavelength at ${\lambda}_{PWM}$, was used to detect the power of the injection-locking signal (optical analog input). If the analog input power is high, the SMFP-LD is locked to the wavelength of the input signal ${\lambda}_a$ and there is no output after an optical bandpass filter (OBF). If the analog input power is low, the SMFP-LD is unlocked and there is output signal at ${\lambda}_{PWM}$ after the OBF. Thus, the SMFP-LD plus the OBF provide digital output for an analog input. The DC of the output PWM signal can be controlled by tuning the power of the analog input.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.617-626
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• 2008

Opportunistic Beamforming (OBF) offers a way to provide the multiuser diversity even in slow fading channel by using randomly generated beam weights, leading to the substantially reduced feedback in the form of the instantaneous SNR from users. In spite of the advantage of the reduced feedback, the imperfect channel estimation might influence the quality of the estimated SNR and channel scheduler so bad that the selected AMC level would be higher than the achievable rate of the actual channel, resulting the corruption of transmitted packet. In this paper, we propose a conservative link adaptation, where the estimated SNR is scaled down by a conservative factor which minimizes the variance of the maximum difference between the actual channel SNR and the resultant SNR. To support the proposed scheme, we analyze the statistics of the difference of the channel SNR and the estimated SNR. Simulation results show that the introduction of conservative factor achieves more than two-fold performance improvement in the presence of channel estimation error and the fairness of PF scheduler is maintained when the least squared channel estimator is applied.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.181-186
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• 1997

A series of 7-deazahypoxanthine and 7-deazaadenine derivatives[6,7.8.9.10,13] as purine antagonists was prepared. The pyrrolidine-5-one derivatives[4,11] were treated vith $(C_2H_5)_3OBF_4$ to give 3- aryl-5-ethoxy-2H-3,4-dihydropyrrole[5,12], which were converted to 7-aryl-7,8-dihydro-7(9H)-deazahy-poxanthine[6,7,8,9,10] and 7-phenyl-2-methyl-7,8- dihydro-7(9H)-deazaadenine[13].

• YAKHAK HOEJI
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• v.37 no.3
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• pp.228-234
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• 1993

A new series of 7-deazapurine derivatives[7,8] as purine antagonists was prepared. Diethyl 4-cyano-N-(diphenyimethylene)-3-arylglutamate[3] were synthesized by LDA-catalyzed Michael addition of N-(diphenylrnethylene)glycine ethyl ester with (E)-2-cyano-3-arylacrylate. Deprotection yields diethyl 4-cyano-3-arylglutamate, which were easily cyclized to 4-cyano-2-ethoxycarbonyl-5-oxo-3-arylpyrrolidine[4]. The compounds[4] were treated with NaBH$_{4}$ and then with (C$_{2}$H$_{5}$)$_{3}$OBF$_{4}$ to give 4-cyano-5-ethoxy-2H-2-ethoxymethyl-3-aryl-3,4-dihydropyrrole[6], which were converted to 7-aryl-6-amino-8-ethoxymethyl-7,8-dihydro-7(3H, 9H)-deazapurine-2-thione[7] and 7-aryl-2,6-diamino-8-ethoxymethyl-7,8-dihydro-7(9H)-deazapurine[8] with possible activity against neoplastic disease.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.212-218
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• 2010

This study was aimed to investigate the contents of chemical components and the biological activity of fermented Omija (Schizandra chinensis Baillon.) beverage (FOB), which have not been well known up to now. General compositions and the contents of mineral and vitamin of FOB were lower than Omija before fermentation (OBF). In addition, most sucrose was digested into glucose and fructose in FOB. This suggests that the beneficial contents may be made from general compositions by fermentation, though more evidences are needed. Antioxidant activity of FOB was measured by using 2,2-diphenyl-l-picryl-hydrazyl (DPPH) free radical scavenging activity and superoxide dismutase-like activity (SODA). DPPH radical scavenging activity and SODA were increased in a dose-dependent manner, and were about 79.7% and 60.8% at four times diluted FOB (25% of FOB), respectively. The FOB also showed strong antibacterial activity on Escherichia coli. Beauty effect of FOB was demonstrated by the analysis of tyrosinase and elastase inhibitory activities, and they were remarkably increased in a dose-dependent manner. Tyrosinase inhibitory activity was about 82% at two times diluted FOB (50% of FOB) and elastase inhibitory activity was 78.2% at five times diluted FOB (20% of FOB). These results suggest that FOB has a strong antioxidant activity, and tyrosinase and elastase inhibitory effects.