• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.746-748
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• 2002

The effect of $MnO_2$ addition in $0.05Pb(Sn_{0.5}Sb_{0.5})O_3-0.8PbZrO_3-0.15PbTiO_3$(0.05PSS-0.8PZ-0.15PT) ceramics on crystal structure and electrical properties were studied. The sintering temperature and time were $1230^{\circ}C{\sim}1270^{\circ}C$ and 2hr, respectively. Then crystal structure, dielectric and pyroelectric properties were investigated. All the poled specimens showed the lower dielectric constant and $tan{\delta}$ than the unpoled specimens. Dielectric constant at 1kHz of the 0.05PSS-0.8PZ-0.15PT(MnO2 0.3wt%) system specimen sintered at $1250^{\circ}C$ for 2hr were 270 and showed the lowest $tan{\delta}$ of 0.2% after poling of $2kV_{DC}/mm$ at $150^{\circ}C$ for 30 minutes. Pyroelectric coefficient was maximum value of $50nC/cm^2K$ and Curie temperature was $224^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1202-1209
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• 2005

The purpose of this study was to observe the effects of high-carbohydrate (HC) diet, high-protein (HP) diet and high-fat (HF) diet with a normal diet (N) on diet-induced thermogenesis (DIT) in healthy Korean women. The four isoenergetic test meals consisted as follows: HC (75$ \% $ energy from carbohydrate, 10$ \% $ from protein and 15$ \% $ from fat), HP (10$ \% $ energy from carbohydrate, 75$ \% $ from protein and 15$ \% $ from fat) HF (15$ \% $ energy from carbohydrate, 10$ \% $ from protein and 75$ \% $ from fat) diet and N (65$ \% $ energy from carbohydrate, 15$ \% $ from protein and 20$ \% $ from fat) diet. Fasting and postprandial thermogenesis were measured after each test meals in eight subjects by indirect calorimetry for 3 hours. Fasting and postprandial serum glucose, insulin and triacylglycerol contents were also measured for 3 hours. DIT were 10.4$\pm$3.2 for HC, 12.7$\pm$0.5 for HP, 6.9$\pm$2.8 for HF and 8.7$\pm$4.8 for N diet as a percentage of the energy load. DIT of HP was greater than HF significantly, but had no differences with HC and N Integrated areas under the curves ($ \delta- $-AUC) of plasma glucose and insulin were significantly higher for HC compared to HP, HF and N diets. $ \delta$-AUC of plasma triacylglycerol was significantly higher for HF compared to the other test meals. In conclusion, intake of protein rich meal stimulates postprandial energy expenditure, but has no relation between DIT and insulin response, body composition.

• Journal of Ginseng Research
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• v.41 no.2
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• pp.144-150
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• 2017

Background: The presence of gross deletions in the human immunodeficiency virus nef gene ($g{\Delta}nef$) is associated with long-term nonprogression of infected patients. Here, we investigated how quickly genetic defects in the nef gene are associated with Korean Red Ginseng (KRG) intakein 10 long-term slow progressors. Methods: This study was divided into three phases over a 20-yr period; baseline, KRG intake alone, and KRG plus highly active antiretroviral therapy (ART). nef gene amplicons were obtained using reverse transcription polymerase chain reaction (PCR) and nested PCR from 10 long-term slow progressors (n = 1,396), and nested PCR from 36 control patients (n = 198), and 28 ART patients (n = 157), and these were then sequenced. The proportion of $g{\Delta}nef$, premature stop codons, and not in-frame insertion or deletion of a nucleotide was compared between three phases, control, and ART patients. Results: The proportion of defective nef genes was significantly higher in on-KRG patients (15.6%) than in baseline (5.7%), control (5.6%), on-KRG plus ART phase (7.8%), and on-ART patients (6.6%; p < 0.01). Small in-frame deletions or insertions were significantly more frequent among patients treated with KRG alone compared with controls (p < 0.01). Significantly fewer instances of genetic defects were detected in samples taken during the KRG plus ART phase (7.8%; p < 0.01). The earliest defects detected were $g{\Delta}nef$ and small in-frame deletions after 7 mo and 67 mo of KRG intake, respectively. Conclusion: KRG treatment might induce genetic defects in the nef gene. This report provides new insight into the importance of genetic defects in the pathogenesis of AIDS.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.80-88
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• 2016

In order to reconstruct a benthic foodweb structure and assess the role of benthic microalgaes as a diet source for benthos, we analyzed the carbon and nitrogen stable isotopes of diverse benthos (bivalves, crustaceans, gastropods and fishes) and potential diets (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass, and macroalgaes) in the intertidal mudflat surrounding Yeongheung Island. The ${\delta}^{13}C$ values of the diets indicated wide ranges (- 26.5‰ to - 8.4‰) while benthos showed a small range of ${\delta}^{13}C$ values (-12.1‰ to - 17.8‰), although they were in the same range. Except for green algaes among the macroalgaes as well as sedimentary organic matter, ${\delta}^{15}N$ values of the diet candidates ($5.7{\pm}1.0$‰) were lighter in comparison to those of the benthos ($11.8{\pm}1.9$‰). Based on the ${\delta}^{13}C$ and ${\delta}^{15}N$ data, the benthos were classified into 3 groups, indicating a different diet and trophic position. But benthic microalgae is the most important diet source for all three benthos groups based on their stable isotope ratios, suggesting benthic microalgae should be a main diet to the intertidal ecosystem. Hence this study highlights that the biomass of benthic microalgae as biological resource should be evaluated for the management of the intertidal ecosystem of Yeongheung Island.

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.234-238
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• 1992

Using cell-free extract of Lysobacter lactamgenus, enzymatic conversion of $\delta$-L-($\alpha$-aminoadiphyl)-L-cysteinyl-D-valine (ACV) the first substrate of $\beta$-lactam biosynthesis, into antibiotic compounds was attempted. In high performance liquid chromatographic (HPLC) analysis, the biosynthetic intermediates for cephalosporin antibiotics including isopenicillin N, deacetoxycephalosporin C, deacetylcephalosporin C and unknown cephem compound were detected in reaction mixtures. It implies that cephabacin compounds from L lactamgenus could be produced by biosynthetic routes through penicillin ring formation and its expansion to cephalosporin ring, likely as cephalosporin C from Cephalosporium or cephamycin C from Streptomyces. Among biosynthetic enzyme in cell-free extract, the ring formation activity (isopenicillin N synthetase activity) was separated in 50-60% of ammonium sulfate fraction, and ring expansion activity (deacetoxycephalosporin C synthetase activity) was found to be in 40-50% fraction. The partially purified isopenicillin N synthetase could convert as much as 90% ACV to isopenicillin N during 6-hour reaction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2444-2450
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• 2011

In this paper, we propose the low fractional spur phase-locked loop(PLL) with multiple phase-frequency detector(PFD). The fractional spurs are suppressed by using a new PFD. The new PFD architecture with two different edge detection methods is used to suppress the fractional spur by limiting a maximum width of the output signals of PFD. The proposed PLL was simulated by HSPICE using a 0.35m CMOS parameters. The simulation results show that the proposed PLL is able to suppress fractional spurs with fast locking.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.439-447
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• 2018

The aromatic compound p-hydroxybenzoate (PHBA) is an important material with multiple applications, including as a building block of liquid crystal polymers in chemical industries. The cytochrome P450 (CYP) enzymes are beneficial monooxygenases for the synthesis of chemicals, and CYP53A15 from fungus Cochliobolus lunatus is capable of executing the hydroxylation from benzoate to PHBA. Here, we constructed a system for the bioconversion of benzoate to PHBA in Escherichia coli cells coexpressing CYP53A15 and human NADPH-P450 oxidoreductase (CPR) genes as a redox partner. For suitable coexpression of CYP53A15 and CPR, we originally constructed five plasmids in which we replaced the N-terminal transmembrane region of CYP53A15 with a portion of the N-terminus of various mammalian P450s. PHBA productivity was the greatest when CYP53A15 expression was induced at $20^{\circ}C$ in $2{\times}YT$ medium in host E. coli strain ${\Delta}gcvR$ transformed with an N-terminal transmembrane region of rabbit CYP2C3. By optimizing each reaction condition (reaction temperature, substrate concentration, reaction time, and E. coli cell concentration), we achieved 90% whole-cell conversion of benzoate. Our data demonstrate that the described novel E. coli bioconversion system is a more efficient tool for PHBA production from benzoate than the previously described yeast system.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.485-495
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• 2018

Background: The geographical origin of Panax ginseng Meyer, a valuable medicinal plant, is important to both ginseng producers and consumers in the context of economic profit and human health benefits. We, therefore, aimed to discriminate between the cultivation regions of ginseng using the stable isotope ratios of C, N, O, and S, which are abundant bioelements in living organisms. Methods: Six Korean ginseng cultivars (3-yr-old roots) were collected from five different regions in Korea. The C, N, O, and S stable isotope ratios in ginseng roots were measured by isotope ratio mass spectrometry, and then these isotope ratio profiles were statistically analyzed using chemometrics. Results: The various isotope ratios found in P. ginseng roots were significantly influenced by region, cultivar, and the interactions between these two factors ($p{\leq}0.001$). The variation in ${\delta}^{15}N$ and ${\delta}^{13}C$ in ginseng roots was significant for discriminating between different ginseng cultivation regions, and ${\delta}^{18}O$ and ${\delta}^{34}S$ were also affected by both altitude and proximity to coastal areas. Chemometric model results tested in this study provided discrimination between the majority of different cultivation regions. Based on the external validation, this chemometric model also showed good model performance ($R^2=0.853$ and $Q^2=0.738$). Conclusion: Our case study elucidates the variation of C, N, O, and S stable isotope ratios in ginseng root depending on cultivation region. Hence, the analysis of stable isotope ratios is a suitable tool for discrimination between the regional origins of ginseng samples from Korea, with potential application to other countries.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.53-61
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• 2014

The origin of particulate organic matter (POM) and food web structure were investigated in Shingu reservoir based on stable isotope analysis from pre-monsoon (July) to post-monsoon (September) 2007. According to the depth in Shingu reservoir, the $^{13}C$ and $^{15}N$ values of POM for pre-monsoon period were nonsignificant distinction, while it was significant variation after rainfall period. The ${\delta}^{13}C$ values of POM in premonsoon period ranged from -25.1‰ to -26.1‰ in whole water column, but the ${\delta}^{13}C$ values of POM in post-monsoon period showed relatively wide range between -23.2‰ and -27.5‰. The apparently lighter values (average -27.5‰) in near bottom water (7 m water depth) demonstrate that POM in high turbid water in post-monsoon period may be derived from the outside terrestrial plants (allochthonous) through heavy rainfall during the summer monsoon period. After rainfall period, $^{13}C$ and $^{15}N$ values of D. brachyurum showed -23.3‰ and 12.2‰, respectively, while B. longirostris showed -27.1% and 8.7%, respectively. It suggested that D. brachyurum mainly feed on POM in autochthonous organic matter pool, but B. longirostris mainly consumed POM in allochthonous organic matter pool after rainfall period. Carbon and nitrogen stable isotope ratios were markedly different among secondary consumers. The carp (C. carpio) and catfish (S. asotus) were in the higher trophic level and crucian carp (C. auratus) and mudfish (M. mizolepis) were in the lower trophic level. $^{13}C$ and $^{15}N$ values of Z. platypus didn't significantly changed between before and after rainfall period. But P. parva and C. auratus apparently changed the $^{13}C$ and $^{15}N$ values after rainfall period. It is suggested that P. parva and C. auratus seem to feed allochthonous food source while Z. platypus depend on autochthonous food source.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.29-32
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• 1991

Non-volatile SNOSFET memory devices using CMOS 1Mbit design rule(1.2$\mu\textrm{m}$), whose channel width and length are 15${\times}$1.5$\mu\textrm{m}$, 15${\times}$1.5$\mu\textrm{m}$, 2.0${\times}$15$\mu\textrm{m}$ and length are 15${\times}$1.7$\mu\textrm{m}$, respectivley, were fabricated. And the transfer, Id-Vd and switching characteristics of the devices were investigated. As a result, the 15${\times}$1.5$\mu\textrm{m}$ device was good in the transfer characteristics and the switching characteristics were favourable, which had $\Delta$V$\sub$TH/=6.3V by appling pulse voltage of V$\sub$w/=+34V, Tw=50msec.