• Steel and Composite Structures
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• 제39권2호
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• pp.135-148
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• 2021

Hollow structural section (HSS) columns have been increasingly popular due to their structural and architectural merits. However, practical difficulty lies in developing proper connections. The through-diaphragm connections are considered as suitable connection type that is widely adopted in Asian countries. However, the stress concentration occurs at the location connecting through-diaphragm and steel beam. Furthermore, the actual load path from the beam flange is not uniformly transferred to the HSS column as conventionally assumed. In this paper, tensile tests were further conducted on three additional specimens with beam flange plate to evaluate the load versus displacement response. The load-displacement curves, yield and ultimate capacity, ductility ratio were obtained. Furthermore, the strain development at different loading levels was discussed comprehensively. It is shown that the studied connection configuration significantly reduces the stress concentration. Meanwhile, simplified trilinear load-displacement analytical model for specimen under tensile load was presented. Good agreement was found between the theoretical and experimental results.

• Applied Biological Chemistry
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• 제16권2호
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• pp.85-93
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• 1973

These experiments were carried out to study influences of the kind of yeasts and of brewing condition on fermentation of Takjoo mash. The results obtained were as follows: 1. Kind of yeasts and the number of yeasts in mash. When the first stage mash was fermented at $20^{\circ}C$ for $1.5{\sim}2.5$ days and at $25^{\circ}C$, $30^{\circ}C$ for $1{\sim}2days$, in the second stage mash that was fermented at high temperature, the number of yeasts was less as compared with the case of fermentation at low temperature, but the living yeasts number of Takjoo yeast strain Dm-1 was more than those of sake yeast, strain No. 7. 2. Kind of yeasts and composition of ripened mash. 1) In the secondstage mash that was fermented at high temperature($30{\sim}35^{\circ}C$), alcohol percentage of ripened mash using the selected Takjoo yeasts (strains: Dm-1, Y-1) was remarkably higher than the case of another yeasts (strains: No.7, No.6, No. 396, No. 1). 2) Acidity of mash had a little differences between strain Dm-1 and strain No. 7. 3) In the second stage mash that was fermented at high temperature ($30{\sim}35^{\circ}C$), the amount of Formol-N using strain Dm-1 was remarkably less than strain No.7. 3. Brewing condition and alcohol percentage of mash. 1) The fit amount of wheat bran Kuk addition per material was 3 percentage and it was adequate to use the mixture of wheat flour Kuk 20 percentage and wheat bran Kuk 1-2 percentage. 2) Though brewing concentration of the first stage mash was duiluted by twice of general brewing concentration, the yeast reproduction was normal. 3) In addition of wheat flour $80{\sim}140g$ per 180ml water, alcohol percentage of the mash increased almost propotionally according to the increase of the amount of wheat flour. 4) It was recognized that three stage brewing was superior in method to two stage brewing at present.

• International Journal of High-Rise Buildings
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• 제9권4호
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• pp.325-334
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• 2020

This paper aims to evaluate the interfacial stress concentrations on connection between vertical through-plate and H-beam in CFT column. Full-scale experiments were performed on three specimens with varying thickness of the vertical through-plate to investigate the interfacial stress concentration factor in the connections. The specimens underwent brittle failure at the location where the steel beam is connected to the vertical through-plate before the steel beam reached its plastic moment. The strain data of the part were analyzed, and the sectional analyses were conducted to determine appropriate residual stress models. In addition, the stress concentration factor was quantified by comparing the analytical local behavior in which the stress concentration is not reflected and the experimental data reflecting the stress concentration. The results showed that the maximum reduction of the stress concentration factor due to an increase in the thickness of the vertical through-plate is 50.3%.

• Journal of the East Asian Society of Dietary Life
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• 제17권4호
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• pp.563-570
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• 2007

This study was performed to observe the antioxidative effects, antimutagenic capacity, and cytotoxic activity of the 70% ethanol extract, and fractions, of Agaricus blazei Murill mycelium, using DPPH free radical scavenging ability, the Ames test, and SRB assay, respectively. Among the fractions, ethyl acetate showed the most effective antioxidative capacity according to the $RC_{50}$(73.6 $\mu$g/mL) of the scavenging effect on the DPPH radical. The inhibition rate of both the aqueous fraction and 70% ethanol extract(200 $\mu$g/plate) toward the Salmonella typhimurium TA100 strain was 94.6%, and it was 89.4% against the mutagenesis induced by MNNG(0.4 $\mu$g/plate). In addition, an identical concentration of the 70% ethanol extract in the TA98 strain, and the ethyl acetate fraction in the TA100 strain, showed inhibition rates of 80.3% and 76.9%, respectively, the highest activities against the mutagenesis induced by 4NQO(0.15 $\mu$g/plate). The cytotoxic effects of the 70% ethanol extract and its fractions increased with increasing sample concentration against human cervical adenocarcinoma(HeLa), human hepatocellular carcinoma(Hep3B), human breast adenocarcinoma(MCF-7), human stomach adenocarcinoma(AGS), and human lung carcinoma (A549). A 1 mg/mL concentration of the ethyl acetate fraction showed cytotoxicities of 77%, 83.8%, 82.1%, 83.1%, and 92.6% against HeLa, Hep3B, MCF-7, AGS and A549, respectively.

• Journal of Marine Bioscience and Biotechnology
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• 제1권4호
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• pp.260-267
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• 2006

The Liquid Culture Assay using a recombinant Agrobacterium tumefaciens strain has been developed as a means for quorum sensing autoinducer screening. However, the low aqueous solubility of marine natural product extracts used as potential autoinducers has been a hindrance in the screening process. Although the addition of organic solvents and/or surfactants could increase aqueous solubility, errors in data interpretation including false positive results could be a serious problem. Therefore, determining the best possible solvent and surfactant at the optimum concentration is crucial. Evaluating methanol, ethanol, 1-propanol, DMSO and DMF at concentration ranges of 0~10% revealed < 2% methanol to be most favorable when tested for ${\beta}$-gal activity and growth inhibition of the recombinant A. tumefaciens strain. On the other hand, among surfactants tested, Triton X-100 was similarly effective in increasing the delivery of autoinducers for activity at less than 0.05% concentration.

• Microbiology and Biotechnology Letters
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• 제30권3호
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• pp.216-222
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• 2002

To Produce the modified Cheongiu that has high ethanol content, an ethanol-tolerant strain Saccharo-myces cerevislae SE2l1 was screened from Saccharomyces cerevisiae Kyokai No. 10 strain. The isolate showed faster growth than in the medium containing 10% ethanol compared with original strain. The isolate produced a higher concentration of ethanol and showed higher resistance to ethanol, high osmolarity and heat than the original strain. The analyses of yeast membrane components indicated that there were no significant changes in composition of sterols and phospholipids between the isolated and the original strain. However, during the fermentation, the iso-lated strain could change the fatty acid composition in the membrane more rapidly in the direction of decreasing membrane unsaturation and accumulate more trehalose in the cell than the original strain. These data suggest that the ability to change its membrane fatty acid composition and to accumulate trehalose may make the isolated strain easily adapt to changes in external condition.

• Microbiology and Biotechnology Letters
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• 제37권2호
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• pp.176-182
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• 2009

Hydrogen producing bacterium, strain MeL 6-2 was isolated from the sludge of the factory areas in Anyang through the acclimation in basal salt medium (BSM) supplemented with 10 g/L of sucrose. Isolated strain MeL 6-2 was a facultative anaerobe which could grow in both aerobic and anaerobic environments. An aerobically grown pure culture isolated from enriched culture was analyzed by 16S rDNA sequencing and identified as Rhodopseudomonas sp. MeL 6-2. Effects of the concentrations of glucose and sucrose on the hydrogen production rate and the hydrogen production yield were investigated. When glucose in the range of 1~12 g/L was supplemented to the BSM, strain MeL 6-2 could grow without lag phase. An increased glucose concentration increased the specific hydrogen production rate linearly to $4.2\;mmol-H_2{\cdot}L^{-1}{\cdot}h^{-1}$ at 10 g/L, and $60\;mmol-H_2{\cdot}mg-DCW^{-1}{\cdot}h^{-1}$, but decreased slightly as the concentration increased to 12 g/L. The hydrogen production yield was maintained over a range from 2.6 to $3.1\;mol-H_2{\cdot}mol-glucose^{-1}$. When sucrose in the range of 1~12 g/L was supplemented to the BSM, strain MeL 6-2 could grow after ten hours. An increased sucrose concentration increased the specific hydrogen production rate and the hydrogen production yield to $163\;mmol-H_2{\cdot}mg-DCW^{-1}{\cdot}h^{-1}$ and to $4.5\;mol-H_2{\cdot}mol-sucrose^{-1}$, respectively.

• Microbiology and Biotechnology Letters
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• 제31권1호
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• pp.83-89
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• 2003

2,4-Dichlorophenoxyacetic acid (2,4-D) as a widely used herbicide has caused serious environmental problems because of its difficult decomposition in nature. We isolated the strain capable of metabolizing 2,4-D as sole carbon and energy source by an enrichment culture technique from the 2,4-D contaminated soil collected at orchard in Gwangju, Korea. This strain was identified tentatively as Aeromonas sp. NOH2. With this strain, we established the response surface methodology (Box-Behnken Design) to optimize the principle parameters for maximizing biodegradation of 2,4-D such as culture pH, temperature, and nutrient concentration in liquid batch culture. The ranges of parameters were obtained from preliminary works done at our laboratory and chosen as 5.5, 6.5, and 7.5 for pH, 25, 30, and $35^{\circ}C$ for temperature, and 5, 20, and 35 g/1 nutrient concentration. Initial concentration of 2,4-D was 500 ppm and nutrient source was tryptic soy broth. The experimental data were significantly fitted to a second order polynomial equation using multiple regression. The most important parameter influencing 2,4-D degradation and biomass production was nutrient concentration. For 2,4-D degradation, the optimum values of pH and temperature, and nutrient concentration were obtained at pH (6.5), temperature (31.8 to $32.1^{\circ}C$), and nutrient concentration (29.6 to 30.1.0 g/1).

• Journal of Microbiology
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• 제45권6호
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• pp.499-504
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• 2007

A new antagonistic strain of actinomycete, designated AP19-2, was isolated from the feces of giant pandas inhabiting the Foping National Nature Reserve in China. Cultural characteristic studies strongly suggested that this strain is a member of the genus Streptomyces. The nucleotide sequence of the 16S rRNA gene of strain AP19-2 evidenced profound similarity (97-99 %) with other Streptomyces strains. Two pure active molecules were isolated from a fermentation broth of Streptomyces sp. strain AP19-2 via extraction, concentration, silica gel G column chromatography, and HPLC. The chemical structures of the two related compounds (referred to as chromomycin $A_2$ and chromomycin $A_3$) were established on the basis of their Infrared spectra (IR), High Resolution Electrospray Ionization Mass Spectrometry (HR-ESI-MS), and Nuclear Magnetic Resonance (NMR) data, and by comparison with published data.

• KSBB Journal
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• 제17권3호
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• pp.295-301
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• 2002

The effects of nonionic surfactant (SPAN 20) on the desulfurization process by Rhodococcus sp. strain IGTS8 have been investigated at various oil/water ratios, pHs and concentrations of surfactant. The hexadecane containing DBT was employed as model oil. The presence of surfactant in the oil/water mixture stabilized the oil/water interface, thus enhanced the efficiency of desulfurization. The volume percentages of oil in the oil/water mixture were 30, 50 and 70%. The concentrations of surfactant were varied from 0 to 0.33 wt% relative to water phase. In general, the biodesulfurization efficiencies were decreased as the concentration of SPAN 20 and the volume percentage of oil phase increased.