• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.758-767
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• 2014

In this study, we selected an Escherichia coli strain (E. coli MG 1655) metabolizing arabinose derived from acid hydrolyzed black liquor as a carbon source and investigated effect of organic acids (acetic acid, formic acid, and lactic acid) presented in black liquor on growth of the E. coli MG 1655. We measured growth of E. coli MG 1655 under various concentration of each and combined three kinds of organic acids. The E. coli MG 1655 shows tolerance to acetic acid, lactic acid and formic acid at these concentrations ($1.0g/{\ell}$ acetic acid, $1.2g/{\ell}$ lactic acid and $0.8g/{\ell}$ formic acid, respectively), but displays some growth retardation over $1.5g/{\ell}$ acetic acid, lactic acid $2.0g/{\ell}$, and formic acid $1.2g/{\ell}$, respectively. In addition, formic acid was shown to be a critical factor affecting growth of the E. coli MG 1655 in the presence of three kinds of organic acids. These results indicate that the inhibitors should be removed at least $1.0g/{\ell}$ of acetic acid, $1.2g/{\ell}$ of lactic acid, $0.8g/{\ell}$ of formic acid for normal cell growth required for high yield fermentation. In addition, there is a need to construct recombinant strains that may be resistant to the same or higher organic acids concentration (> $1.2g/{\ell}$) in the growth.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.23-29
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• 1989

Biochemical consequence of the accumulation in cells of superoxide $(O^{-}_{2})$ which was proposed to be probably a common chemical factor in the secondary process of the mechanism of chilling injury as well as in the visible light photodamage in cells of higher plants, has been investigated in the present work. Especially focused was the destructive effect of $O^{-}_{2}$ on the biochemical activity of mitochondria, as informations which support the suggestion that mitochondrial inner membrane is the major site of $O^{-}_{2}$ production have been collected. Mitochondria and submitochondrial particles (SMP) were prepared from soybean hypocotyls for this case study. When SMP were treated with the electrolytically produced $O^{-}_{2}$ they suffered not only inhibition of the membrane-bound enzymes as demonstrated by cytochrome c oxidase, but also lipid peroxidation of membrane as proved by malondialdehyde production. Malate dehydrogenase present in the protein extract from mitochondrial matrix was also inhibited by the $O^{-}_{2}$ treatment. These results exhibited the chaotic effect of the overproduction and accumulation of $O^{-}_{2}$ in cells under a certain abnormal circumstance such as environmental stress on the physiological function of mitochondrial; disruption of the cellular metabolic pathways and the structural integrity of membrane.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.421-427
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• 2015

Angelica gigas Nakai is one of the most widely used herbal medicines and is known to have many pharmaceutical effects including an anti-oxidant, anti-cancer etc. This study was carried out to investigate an effect of fertilization on leaf yield, production of dry-matter and accumulation of pyranocurmarine compounds such as decursin (DE) and decursinol angelate (DA) in Angelica gigas Nakai. Effect of fertilization was determined from response surface regression equation composing of 2 by 3 factorial arrangement of urea, sodium dihydrogen phosphate and potassium chloride. Yield of leaf in Angelica gigas Nakai significantly increased until 100 days after transplanting. Production of leaf also tended to increase with increasing nitrogen fertilization. Model of regression equation showed that leaf production depended upon nitrogen ($Pr>{\mid}t{\mid}$ : 0.087, 0.256 and 0.079). Also, statistical results between nitrogen application level and production of dry-matter showed significant relationship (p<0.05) and contents of dry-matter was highest in 10 kg 10a-1 treatment on 24 Sep. Active compound isolated and purified from leaf and root of Angelica gigas Nakai was identified as DE and DA by gas chromatograph-mass spectrophotometry (GC-MS). Concentration of DA as prevalent compound in leaf was highest on 20 Aug. but decreased on 24 Sep. Amount of DE and DA accumulated in Angelica gigas Nakai significantly increased with growth stages and nitrogen level. The result of our investigation imply that nitrogen fertilization is important factor for production of leaf and accumulation of pyranocurmarine in Angelica gigas Nakai as a medicinal/food materials.

• Journal of Life Science
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• v.31 no.10
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• pp.960-968
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• 2021

Since microalgae research started on late 18 century, they have been recognized as one of the most important bioresources used in bioindustry. Owing to the large efforts paid to industrial application of this microorganisms, their importance on food/feed and bioactive compounds has been further extending into the environmental research areas including alternative energy resources, mitigation of the carbon emission, and waste-water treatment. However, despite the importance on their industrial application, the fundamental research field related to the long-term preservation of microalgae culture has not received much attention. However, a less labor intensive and cost-efficient preservation technology enabling biologically active and stable microalgae-culture provides a key success factor in the biotechnological application. Therefore, this study investigated various cutting-edge microalgae cryopreservation technologies currently developed so far, mainly targeting Chlorophyta, which occupies the largest taxon in the classification system of microalgae. In addition, for the development of successful cryopreservation technique, the key factors such as temperature control effect and preservative effect during cryopreservation of microalgae culture were investigated. In addition, the problems with current preservation technology that is being used in Korean domestic biological resource banks and the international microalgal resource banks are described. According to our investigation, currently no standard method for long-term preservation of microalgae is available due to their various morphological and physiological characteristics. To overcome such issues, much more efforts on fundamental research area on the identification of specific biomarker used for microalgae taxonomical classification and further systemic approaches based on strain-specific cryopreservation methods needed.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.397-408
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• 2021

The purpose of this study is to investigate the effect of teaching style of liberal arts physical education professors to class satisfaction, Class flow and physical education attitude of liberal arts students. A study was conducted on a total of 221 liberal arts students. For the collected data, a confirmatory factor analysis and reliability analysis (Cronbach' α) for the measurement tool were performed using the SPSS 26.0 and Amos 21.0 programs. And correlation analysis and multiple regression analysis were performed. The liberal arts physical education Professor's teaching stlye affects the student's class satisfaction (educational satisfaction, environmental satisfaction, psychosocial satisfaction, physical satisfaction), and students' class flow (class immersion, purpose experience, consciousness agreement, challenge, control, Integration). In addition, it has various effects on the student's attitude toward physical education(relationships, physical activity, active participation, health and physical fitness, positive emotions). Efforts to strengthen the competence of liberal arts physical education professors will be needed to revitalize the liberal arts physical education.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.887-894
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• 2018

An electric vehicle is emerging as an alternative to the response of global climate change and sustainability. However, an Electric vehicle has not been popular due to the constraints such as its price or technical limitations. In order to analyze the effect of purchasing electric vehicles, this study conducted a binary logistic regression model that demonstrates the relation between purchasing and influencing variables. Variables which have high correlation were excluded from the model through the correlation analysis to prevent multicollinearity. Socio-economic variables such as the number of owned vehicles, sex, ages are not significant. On the other hand, Variables related to prices, charging and policy are found to have a significant to effect on the purchase of electric vehicles. In accordance with the model estimated result, it seems to be necessary to improve the charging incentives, or to provide electric car information and to expand opportunities for experience electric vehicles. The result is also expected to be helpful for spreading electric vehicles and formulating policies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.5
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• pp.617-626
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• 2022

In Korea, annual precipitation and its variability have gradually increased since modern meteorological observations began, and the risk of disasters has also been increasing due to significant regional variations and recent abnormal climate conditions. Given that damage from storms and floods mainly occurs around rivers, it is crucial to determine the appropriate design frequency for river-related projects. This study examined existing design practices used to determine hydrological design frequencies and suggested a new method to determine appropriate design frequencies. The study collected available data pertaining to seven evaluation factors, specifically the basin areas, shape parameters, channel slopes, stream orders, backwater effect reaches, extreme rainfall frequencies, and urbanized flood inundation areasfor 413 local rivers in Chungcheongnam-do in Korea. The estimated weights for areas of extreme rainfall frequencies and urbanized flood inundation were found to be 18, having a great effect on determining the design frequency. Compared with the established design frequency in previous government reports, the estimated design frequency increased for 255 rivers and decreased for 158 rivers.

• Journal of the Korean Society for information Management
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• v.39 no.1
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• pp.17-44
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• 2022

The purpose of this study was to present a plan on the effect of non-face-to-face services on library anxiety facilities by analyzing the library anxiety factors of university library users. To this end, we look at the cases of university library user service response activities in response to the COVID-19 crisis and select 40 schools with the highest number of library visitors per student from among domestic four-year university libraries with 5,000 or more and less than 10,000 students. Methods of information service and program cases were analyzed, and K-LAS was reconstructed and surveyed for current students using the K university library, and frequency analysis, descriptive statistical analysis, exploratory factor analysis, and reliability analysis, correlation analysis, and multiple regression analysis were applied to analyze the library anxiety factors of users. Identify the relationship between 5 library anxiety factors and non-face-to-face service activation factors, such as physical/environmental factors of the library, data search selection factors, digital information system factors, librarian (staff) factors, and psychological/emotional factors, and activate non-face-to-face services. The influence of these factors on library anxiety factors was examined, and as a result, it was found that non-face-to-face service activation factors had the greatest influence on library digital information system anxiety factors. Based on the analysis results, it was attempted to derive a plan to relieve users' library anxiety by activating non-face-to-face services.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4C
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• pp.205-212
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• 2008

In this research, the effect of rock mass weathering on the side shear resistance of drilled shaft socketed into igneous-metamorphic rock was investigated. For that, 23 cast-in-place concrete piles with diameters varying from 400mm to 1,500mm were constructed at four different sites, and the static axial load tests were performed to examine the resistant behavior of the piles. A comprehensive field/laboratory testing program at the field test site was also performed to describe the in situ rock mass conditions quantitatively. The side shear resistance of rock socketed piles was found to have no intimate correlation with the compressive strength of the intact rock. However, the global rock mass strength, which was calculated by the Hoek and Brown criteria, was found to closely correlate to the side shear resistance. The ground investigation data regarding the rock mass conditions (e.g. $E_m$, $E_{ur}$, $p_{lm}$, RMR, RQD, j) were also found to be highly correlated with the side shear resistance, showing the coefficients of correlation greater than 0.75 in most cases. Additionally, the applicability of existing methods for the side shear resistance of weathered granite-gneiss was verified by comparison with the field test data. The existing methods which consider the effect of rock mass condition were modified and/or extended for weathered rock mass where mass factor j is lower than 0.15, and RQD is below 50%.

• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.151-160
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• 2023

Cyanobacteria Pseudanabaena strains are known to produce 2-MIB(odorous material) in freshwater systems, thereby causing problems in water use. However, their physiological responses to environmental factors in relation with 2-MIB production is not well explored. This study was conducted to evaluate the effect of temperature on the growth and 2-MIB production of Pseudanabaena redekei. The experimental cyanobacteria strains were separated from the Uiam Reservoir (North Han River) and cultured in the BG-11 medium. Temperature was set to 10, 15, 20, 25, and 30℃ for the experiment, in the reflection of the seasonal water temperature variation in situ. For each temperature treatment, cyanobacterial biomass(Chl-a) and 2-MIB concentration (intra-cellular and extra-cellular fractions) were measured every 2 days for 18 days. Both maximal growth and total 2-MIB production of P. redekei appeared at 30℃. While intra-cellular 2-MIB contents were similar (26~29 ng L^-1) regardless of treated temperatures, extra-cellular 2-MIB concentration was higher only in high temperature conditions (25~30℃), indicating that the extents of 2-MIB biosynthesis and release by P. redekei vary with temperature. The 2-MIB productivity of P. redekei was much higher in low-temperature conditions (10~15℃) than high temperature conditions (25~30℃). This study demonstrated that temperature was a critical factor contributing to 2-MIB biosynthesis and its release in cell growth (r=0.605, p<0.01). These results are important to understand the dynamics of 2-MIB in the field and thereby provide basic information for managing odorous material in drinking water resources.