• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.235-243
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• 2006

The study was performed to identification of producing microbe Non-Cariogenicity Sugar (NCS; Fuc($1{\to}4$) gaINAc($2{\to}6$)NeuAc) with anti-caries activity, and to optimization of production condition. A typical strain which produced the NCS was identified alkalophilic Bacillus sp. S-1013 through the results of morphological, biochemical and chemotaxonomic characteristics and 16S rDNA sequencing. The optimal medium composition for the maximal production of the NCS from alkalophilic Bacillus sp. S-1013 was as follow: soluble starch 30 g, dextrin 15 g, yeast extract 5 g, peptone 10 g, $K_{2}HPO_4$ 2 g in a liter of distilled water. Optimal temperature and pH were 25 and 11.0, respectively. The highest production of NCS was shown 60 hrs cultivation using the optimal medium, and then NCS productivity and dry cell weight of culture broth increased 4.24 and 2.67 time than initial medium, respectively.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.97-102
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• 2017

Catechol type siderophore different from 2, 3-dihydroxybenzoic acid (DHB) was produced from Acinetobacter sp. B-W grown in medium containing L-glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$. Optimal concentration of glutamic acid for siderophore production was 3% and production of siderophore was decreased above 3% glutamic acid. In previous report, siderophore, 2, 3-DHB was produced from strain B-W grown in medium containing glucose as carbon source and glutamic acid as nitrogen source. Rf value of siderophore produced from strain B-W grown in medium glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$ was 0.32, while 2, 3-DHB was 0.84 in butanol-acetic acid-water (12:3:5) as developing solvent. Antioxidative activity of 2, 3-DHB was not detected in that siderophore produced from glutamic acid. Catechol nature of siderophore was detected by Arnow test. Although in iron-limited media optimal cell growth was identified at $36^{\circ}C$, significant quantities of siderophore were produced only at $28^{\circ}C$. Biosynthesis of siderophore was strongly inhibited by growth at $36^{\circ}C$. Production of siderophore was completely inhibited by $10{\mu}M\;FeCl_3$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.529-537
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• 2021

Membrane-type hull and cargo holds have been designed and built for large ship. However, there is a growing interest in applying the same technology to small and medium-sized Liquefied natural gas(LNG) carriers to meet the recent increase in demand for LNG as an ecofriendly fuel and for expanding LNG bunkering infrastructure. The purpose of this study is to apply the IMO Type-B tank to small and medium-sized LNG carriers and verify the safety and suitability of the design. Fatigue crack propagation analysis was performed to install a partial second drip tray installed at the lower part of the LNG cargo tank by calculating the amount of leaked gas in the support structure supporting the cargo tank. First, a program for fatigue crack propagation analysis was developed, in which Paris' law and British Standard 7910 (BS 79110) were applied based on the International Code for the Construction of Equipment and Ships Carrying Liquefied Gases in Bulk, an international standard for LNG carriers. In addition, a surface crack propagation analysis was performed. Next, a methodology for assuming the initial through-crack size was developed to determine the size of the partial second barrier. The analysis was performed for 15 days, which is a possible return time after cracks are detected. Finally, the safety and suitability of the IMO Type-B for LNG cargo tanks required by international regulations were verified. For the accurate analysis of fatigue crack propagation, it is necessary to develop and verify the analysis procedure based on direct analysis and international regulations.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.825-833
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• 2017

Strain IMCC26207 was isolated from the surface layer of Lake Soyang in Korea by the dilutionto-extinction culturing method, using a liquid medium prepared with filtered and autoclaved lake water. The strain could neither be maintained in a synthetic medium other than natural freshwater medium nor grown on solid agar plates. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain IMCC26207 formed a distinct lineage in the order Acidimicrobiales of the phylum Actinobacteria. The closest relative among the previously identified bacterial taxa was "Candidatus Microthrix parvicella" with 16S rRNA gene sequence similarity of 91.7%. Here, the draft genome sequence of strain IMCC26207, a freshwater actinobacterium, is reported with the description of the genome properties and annotation summary. The draft genome consisted of 10 contigs with a total size of 3,316,799 bp and an average G+C content of 57.3%. The IMCC26207 genome was predicted to contain 2,975 protein-coding genes and 51 non-coding RNA genes, including 45 tRNA genes. Approximately 76.8% of the protein coding genes could be assigned with a specific function. Annotation of the IMCC26207 genome showed several traits of adaptation to living in oligotrophic freshwater environments, such as phosphorus-limited condition. Comparative genomic analysis revealed that the genome of strain IMCC26207 was distinct from that of "Candidatus Microthrix" strains; therefore, we propose the name "Candidatus Limnosphaera aquatica" for this bacterium.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.189-194
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• 2020

Daphne pseudomezereum var. koreana is native to Korea and is distributedin Kangwon-do, Jeollabuk do, and Gyeongsang-do. This economically valuable species has experienced a dramatic decrease in natural habitat due to climate change and is difficult to cultivate. In this study, we investigate a mass propagation method for D. pseudomezereum through in vitro culture and genetic resource preservation.WPM medium was better than the MS medium for shoot growth. As a result, we compared the shoot number and length of apical (W/AP) and non-apical shoots (W0/AP) with BA and GA₃ treatments in WPM medium. Their shoots and length grew well in both BA 8ìM + GA₃8ìM-treated apical shoot and without-apical shoot. NAA did not effectively induce rooting of the in vitro plantlet.

• Economic and Environmental Geology
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• v.34 no.4
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• pp.345-354
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• 2001

The effects on arsenic geochemistry of indigenous microorganisms isolated from an area contaminated with high concentration of arsenic were investigated. Arsenite exerted higher inhibitory effects on the microbes' growth than arsenate. During incubation of the microbes in an arsenate-spiked medium over 24 hours, decrease in microbial growth was observed as arsenate content increased. Arsenate of 150 mM or over apparently inhibited cell growth. However, further incubation for up to 4 days in the high arsenate concentration medium resulted in cell growth, implying that the microorganisms adjusted their biochemical functions to detoxify arsenic and maintain growth. Two types of microbes were observed during 20 hours to reduce arsenate to arsenite in solution through a detoxification mechanism. As well, decrease in the total arsenic content occurred over a 4-day incubation with the same microbes in an arsenate-spiked medium. Therefore it is suggested that microorganisms can influence arsenic speciation in natural settings and this may be applied to efficient bioremediation of arsenic-contaminated sites.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.253-263
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• 2016

Fungi, such as the wood-rotting Polyporus brumalis, are excellent sources of pharmaceutically interesting natural products such as sesquiterpenoids. In this study, we investigated the biosynthesis of P. brumalis sesquiterpenoids on modified medium. Ten additional species of white rot fungi were inoculated in medium containing nutrients such as $C_6H_{12}O_6$, $C_4H_{12}N_2O_6$, $KH_2PO_4$, $MgSO_4$, and $CaCl_2$ at $28^{\circ}C$ for 25 days. After 10 days of incubation, eudesmane-type sesquiterpenes, ${\beta}$-eudesmane and ${\beta}$-eudesmol, were only synthesized during the growth phase of P. brumalis. Experiments excluding one nutrient at a time were conducted to determine the effects of inorganic nutrients on sesquiterpene biosynthesis. In conclusion, GC-MS analysis showed that biosynthesis of sesquiterpenes was differentially regulated by inorganic nutrients such as $MgSO_4$, $C_4H_{12}N_2O_6$, and $KH_2PO_4$. We found $MgSO_4$ supplementation to be vital for eudesmane-type sesquiterpene biosynthesis in P. brumalis; nitrogen ($C_4H_{12}N_2O_6$) and phosphate ($KH_2PO_4$) inhibited the synthesis of P. brumalis metabolites. Magnesium is a known cofactor of sesquiterpene synthase, which promotes ${\beta}$-eudesmol synthesis. To mechanistically understand eudesmane-type sesquiterpene biosynthesis in P. brumalis, further research into the genes regulating the dynamics of such biosynthesis is warranted.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.12-21
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• 1997

Nowadays, non-pollution energy sources have been strongly needed because of the exhaustion of fossil fuels and serious environmental problems. Because wind energy can be enormously obtained from natural atmosphere, this type of energy has lots of advantages in a economic and pollution point of view. This study has established the aerodynamic and structural design procedure of the rotor blade with an appropriate aerodynamic performance and structural strength for the 500㎾ medium class wind turbine system. The aerodynamic configuration of the rotor blade was determined by considering the wind condition in the typical local operation region, and based on this configuration aerodynamic performance analysis was performed. The rotor blade has the shell-spar structure based on glass/epoxy composite material and is composed of shank including metal joint parts and blade. Structural design was done by the developed design program in this study and structural analysis, for instance stress analysis, mode analysis and fatigue life estimation, was performed by the finite element method. As a result, a medium scale wind turbine rotor blade with starting characteristics of 4m/s wind speed, rated power of 500㎾ at 12m/s wind speed and over 20 years fatigue life has been designed.

• Journal of Plant Biotechnology
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• v.3 no.2
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• pp.95-100
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• 2001

To select the section with shoot formation ability, the calli and shoot formation from three sections (first leaf including cotyledonary node, hypocotyl and cotyledon explants) of 5-days-seedlings of soybean were induced on MS medium supplemented with 1.0 mg/L BAP, 3% sucrose, and 0.3% gelrite for one month. The first leaf section exhibited the highest shoot formation rate (51%), followed the hypocotyl section (10%) and the cotyledon section (0%). The shoot formation rates and shoot number of the four excised sections (whole first leaf, a half of the first leaf, a third of the first leaf and only node) of the first leaf were also investigated on the same medium. A half of the first leaf explant and the third of the first leaf explant had higher shoot formation rates (76-80%) and numbers (3-4 / explants) than those in other two explants. Effects of six cytokinins (kinetin, zeatin, BAP, 2iP, PBA, and TDZ) on shoot formation were determined, using the half of the first leaf explants. Zeatin (1.0 mg/L) exhibited the highest in shoot formation rate (94%) and numbers (8 / explant). In addition, the combined effects of three cytokinins (zeatin, BAP, and TDZ; 0.5, 1.0, 2.0 mg/L, respectively) and an auxin (IAA; 0.0, 0.5, 1.0, 2.0 mg/L) were determined. The combination (1:1, v/v) of zeatin (1.0 mg/L) and IAA (1.0 mg/L) exhibited the highest in shoot formation rate (96%) and numbers (16 / explant), twice more than zeatin (1.0 mg/L) alone. The shoot cuttings were transferred and cultivated on the rooting media supplemented with only auxin, IBA at various concentrations. The highest root formation (8 / shoot) was achieved on the medium supplemented with 1.5 mg/L. After 4 weeks of cultivation, the plantlets with an extensive root system were transplanted in pots with a soil mixture of vermiculite and fine sand. Transferred to field, about 75% of the plantlets survived.

• Earthquakes and Structures
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• v.11 no.5
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• pp.741-777
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• 2016

A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.