• 전력전자학회논문지
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• 제22권4호
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• pp.297-304
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• 2017

The purpose of this paper is to analyze losses because of switching devices and the secondary side circuit diodes of 500 W full bridge dc-dc converter by applying gallium nitride (GaN) field-effect transistor (FET), which is one of the wide band gap devices. For the detailed device analysis, we translate the specific resistance relation caused by the GaN FET material property into algebraic expression, and investigate the influence of the GaN FET structure and characteristic on efficiency and system specifications. In addition, we mathematically compare the diode rectifier circuit loss, which is a full bridge dc-dc converter secondary side circuit, with the synchronous rectifier circuit loss using silicon metal-oxide semiconductor (Si MOSFET) or GaN FET, which produce the full bridge dc-dc converter analytical value validity to derive the final efficiency and loss. We also design the heat sink based on the mathematically derived loss value, and suggest the heat sink size by purpose and the heat divergence degree through simulation.

• Molecules and Cells
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• 제28권4호
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• pp.397-401
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• 2009

Flavonoids are a group of polyphenolic compounds that have been recognized as important due to their physiological and pharmacological roles and their health benefits. Glycosylation of flavonoids has a wide range of effects on flavonoid solubility, stability, and bioavailability. We previously generated the E. coli BL21 (DE3) ${\Delta}pgi$ host by deleting the glucose-phosphate isomerase (Pgi) gene in E. coli BL21 (DE3). This host was further engineered for whole-cell biotransformation by integration of galU from E. coli K12, and expression of calS8 (UDP-glucose dehydrogenase) and calS9 (UDP-glucuronic acid decarboxylase) from Micromonospora echinospora spp. calichensis and arGt-4 (7-O-glycosyltransferase) from Arabidopsis thaliana to form E. coli (US89Gt-4), which is expected to produce glycosylated flavonoids. To test the designed system, the engineered host was fed with naringenin as a substrate, and naringenin 7-O-xyloside, a glycosylated naringenin product, was detected. Product was verified by HPLC-LC/MS and ESI-MS/MS analyses. The reconstructed host can be applied for the production of various classes of glycosylated flavonoids.

• 생명과학회지
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• 제11권3호
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• pp.279-283
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• 2001

Amyotrophic lateral sclerosis(ALS) is a progressive neurologic disorder resulting from the degeneration of upper and lower motor neurons, and is inherited in 10% of cases. About 20% of familial ALS, clinically indistinguishable from sporadic ALS, is caused by mutations of Cu/Zn superoxide dismutase on chromosome 21q22.21 inherited as an autosomal dominant trait. We now report a new locus in the non-SOD1 dominantly inherited ALS. We screened a large ALS family with 11 affected individuals and one obligate gene carrier with genome-wide ABI polymorphic markers using the ABI 377 automated system. No evidence of linkage was obtained with the autosomal markers. We next screened this family with X chromosome markers as there was no evidence of male-to-male tran-smission of the disease. Linkage was established with several X chromosome markers with a lod score up to 3.8; almost the maximum possible score in this family. Our finding imply that a gene for the dominant expression of a neuronal degeneration is coded on X chromosome and raise the question of the role of X-linked genes that escape inactivation in this pathogenesis. More importantly, our finding that a gene causing ALS is localized on X-chromosome has direct investigational relevance to sporadic ALS, where epidemiological studies show male gender predominance(1.3:1) and earlier onset in men by 5-10 years.

• 한국농촌건축학회논문집
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• 제18권4호
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• pp.1-8
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• 2016

This study is to investigate the meaning and value of Usonian Automatic House System(UAHS) of Frank Lloyd Wright in his later period, focused on materials, methods, and his thoughts. The results of this study are follows. UAHS was the outcome of moderate cost and prefab house which Wright had successively attempted after the early Prairie period. The construction was simple and comparatively cheap, but subsequent automatics were difficult and expensive to build. Nevertheless, it was sufficiently flexible to support a rather wide range of house designs. Concrete was the inert mass and a plastic material. Wright saw a kind of weaving coming out of it. He also saw a kind of concrete masonry, steel for warp and masonry units for woof in the automatic concrete block. The reinforced bars in hollowed joints of concrete block increased the safety factor and affected the expression of the construction through the stabilization they provided. But they did not give concrete block the capability of structural span. Standardization as the soul of the machine might be seen in UAHS. The concrete blocks were more cheap, lighter, and larger hollowed plain than textile blocks in 1920s. But the variety of pattern and different block types in the UAHS were achieved at some sacrifice of standardization. The repetitive nature of production was compromised for artistic goals. The sense of compromise was not maximized, however, because the units as installed looked far more repetitive than they actually were.

• 경영과정보연구
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• 제7권
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• pp.141-168
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• 2001

The causes that the transparency of Korean accounting information was rated low, a short supply of faithful and transparent accounting information from the limitation of external audit environment must be pointed out. Purpose of the external audit is a expression of the auditors about that financial statements an enterprise made public were appropriately drew up in accordance with the corporate accounting principles from important point of view. Analysis of the audit opinion and so fourth according to 6,541 individual audit reports and introduced to the bill securities forward committee as a subject of external audit according to the raw of corporation external audit show that considerable change to the contents of audit report. This show as it is that uncertainty of future that is now being faced by our enterprise, because corporation which present audit reports since 1997 because of enterprise dishonor and contents of existence probability as a continued enterprise following to general economic crisis after 1998 occupy important position in special matters of audit report. Also, increase in special matters is due to application of the corporate accounting principles revised on December 11, 1998. In 1999, audit opinion under limitation(limitation, incongruity and rejecting opinion) increased greatly according to existence doubt as a continued enterprise, and this is the consequence of strengthening audit to the continues enterprise because of limited enterprise dishonor according to the stagnancy of business activities after 1997. Now financial supervisory service put in effect electromagnetic public announcement system about a project report of listed corporation (including an audit report) keeping pace with a documentary public announcement system as first phase since 1999 and expand to the unlisted corporation from 2000. As electromagnetic public announcement of public announcement documents including audit documents of external audit subject get a duty, approach of external user to the accounting information will be easier. Fixation of this system will make deep and wide analysis to the audit opinion, and this will draw up a plan to reconsider confidence of accounting information.

• 대한한방내과학회지
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• 제31권2호
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• pp.189-200
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• 2010

Objectives : Regulatory T cells can reduce inflammation and allergic reactions through their inhibitory functions. Gardeniae Fructus(GF) is a Heat-clearing herb used in traditional Korean medicine, and a wide range of studies on its antiinflammatory effects are being carried out. The authors investigated the effect that Gardeniae Fructus has on regulatory T cells. Methods : The authors screened 14 herbs for their effects on regulatory T cells. 100mg of each herb were separately dissolved in 1ml of sterile saline and the supernatant was harvested after 10 minutes of centrifuge at 15,000 rpm. The supernatant was filtered through a 0.2 ${\mu}m$ syringe filter, and the resulting stock was refrigerated at $4^{\circ}C$. The stock was diluted before testing and used at a final concentration of $0.01{\mu}g/ml$. CD4+CD25+ T cells from healthy BALB/c spleens were used as natural regulatory T cells (nTreg), and CD4+CD25- T cells were used as reactive T cells. CD4+CD25+ and CD4+CD25- T cells were activated with anti-CD3e ($10{\mu}g/m{\ell}$)/anti-CD28 ($1{\mu}g/m{\ell}$) and cultured. IL-10 from supernatant of the culture medium was measured by IL-10 cytokine ELISA. The percentages, cell numbers, phenotype and function of CD4+CD25+ Treg cells were determined by flow cytometry. Results : Gardeniae Fructus was shown to be the most potent herb among the 14 herbs tested for suppressing CD4+CD25- reactive T cell proliferation by stimulating CD4+CD25+ natural regulatory T cells. Gardeniae Fructus induces IL-10 secretion increase by stimulating CD4+CD25+ natural regulatory T cells, and indirectly suppresses CD4+CD25- reactive T cell proliferation through increasing CD25 (IL-2 receptor $\alpha$) expression and thus promoting bonding with IL-2. Gardeniae Fructus did not directly affect CD4+CD25- reactive T cell proliferation. Conclusions : Gardeniae Fructus suppressed reactive T cell proliferation through inducing increases in IL-10 secretion and CD25 (IL-2 receptor $\alpha$) expression.

• 복식문화연구
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• 제5권3호
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• pp.1-25
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• 1997

The consumers, who are characterized by gathering a wide scope of information and by putting into action immediately, have come to the new group searching for emotion and have played a leading role of market. The characgeristics of consumers are the fact that they have followed the street fashion with no-concept, independent of the trends which the brand has provide for consumers. Therefore it leads to a big gap between the fashion information for enterprises and market formation for consumer class. The principal purpose of this paper is to get closer the distance between the information which is used in merchandise plan and real market for consumers, and to suggest the new direction of information management system in order to enhance the hit rate of merchandise plan. The results are as follows : (1) It is shown the enterprises should divide the information data between fashion information and market information, and understand the mutual relationship of them, and regard the statistical data related on the change of sensitivity and desire in market specialized in attributes of street fashion as the emotional expression\`s view, and manage them by the feedback style. (2) It is shown that enterprises should fully understand the fashion factors in the line of fashion stream with the independence of theme in order to plan the merchandise effectively for market which are specialized in the duality that it has both conservation and innovation at the same time, and detect their change. (3) It is shown that in order to predict exactly, enterprises should reflect the statistical data and the emotional factors in planning the merchandise, bring up the systematic organization, expert system. (4) It is also shown that enterprises should make an effort to pursuit the discriminated brand through the feedback management in which the consumer\`s lasting desires are reflected.

• 한국실내디자인학회논문집
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• 제13권3호
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• pp.179-186
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• 2004

The findings of this study indicate that intangible cultural properties are worth preservation and transmission and should be considered as very important as tangible cultural properties. If the studies of intangible cultural properties are continued focusing on their characteristics and formational system, they can be expressed more properly by adding new interactive elements to database and expressive requisites. New techniques introduced in this study are believed to provide people with most reasonable and developmental motives for expression of the existing intangible cultural properties. Concerning Korea's cultural properties centered on intangible cultural properties, information construction should be made with a new idea of information based on database from the previous studies. The result will be able to set an important factor to give wide publicity to our cultural identity, which is currently shown in the process of background communication, and serve as a foothold to deliver exact information to our descendants. The intangible cultural properties are our people's mental cultural heritage resources. If museums or initiator groups, which are organized to spread cultural heritages, can use them as the subjects of exhibition through information construction and visualization, it will function to maximize the educational effect of transmitting our national mental world. The development of digital environment will provide the optimum conditions and tools making it possible to visualize intangible forms and ideas in a virtual cyber space. Given these viewpoints, steady studies and efforts for the improvement of Korea's cultural image should be made in the way of intangible cultural properties as well as tangible ones. They start from the country's accurate appreciation of cultural properties and are embodied in systematic adjustment and relationship between interdependent elements.

• 한국미생물·생명공학회지
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• 제47권4호
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• pp.536-545
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• 2019

Cytochrome P450 (P450 or CYP) is involved in the metabolism of endogenous and exogenous compounds in most organisms. P450s have great potential as biocatalysts in the pharmaceutical and fine chemical industries because they catalyze diverse oxidative reactions using a wide range of substrates. The high-cost nicotinamide cofactor, NADPH, is essential for P450 reactions. Glucose-6-phosphate dehydrogenase (G6PDH) has been commonly used in NADPH-generating systems (NGSs) to provide NADPH for P450 reactions. Currently, only two G6PDHs from Leuconostoc mesenteroides and Saccharomyces cerevisiae can be obtained commercially. To supply high-cost G6PDH cost-effectively, we cloned the cytosolic G6PDH gene of Solanum lycopersicum (tomato) with 6xHis tag, expressed it in Escherichia coli, and purified the recombinant G6PDH (His-G6PDH) using affinity chromatography. In addition, enzymatic properties of His-G6PDH were investigated, and the His-G6PDH-coupled NGS was optimized for P450 reactions. His-G6PDH supported CYP102A1-catalyzed hydroxylation of omeprazole and testosterone by NADPH generation. This result suggests that tomato His-G6PDH could be a cost-effective enzyme source for NGSs for P450-catalyzed reactions as well as other NADPH-requiring reactions.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.304-312
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• 2013

The thermotolerant methylotrophic yeast Hansenula polymorpha is attracting interest as a potential strain for the production of recombinant proteins and biofuels. However, only limited numbers of genome engineering tools are currently available for H. polymorpha. In the present study, we identified the HpPOL3 gene encoding the catalytic subunit of DNA polymerase ${\delta}$ of H. polymorpha and mutated the sequence encoding conserved amino acid residues that are important for its proofreading 3'${\rightarrow}$5' exonuclease activity. The resulting $HpPOL3^*$ gene encoding the error-prone proofreading-deficient DNA polymerase ${\delta}$ was cloned under a methanol oxidase promoter to construct the mutator plasmid pHIF8, which also contains additional elements for site-specific chromosomal integration, selection, and excision. In a H. polymorpha mutator strain chromosomally integrated with pHIF8, a $URA3^-$ mutant resistant to 5-fluoroorotic acid was generated at a 50-fold higher frequency than in the wild-type strain, due to the dominant negative expression of $HpPOL3^*$. Moreover, after obtaining the desired mutant, the mutator allele was readily removed from the chromosome by homologous recombination to avoid the uncontrolled accumulation of additional mutations. Our mutator system, which depends on the accumulation of random mutations that are incorporated during DNA replication, will be useful to generate strains with mutant phenotypes, especially those related to unknown or multiple genes on the chromosome.