• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.95-102
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• 2016

This study investigated the effects of the oxygen permeability of vacuum packaging film and the storage temperature on the quality and shelf life of Hamburg steaks during storage for 14 days. Control samples (C) were packaged in a polyamide/polyethylene (PA/PE) film and stored at $5^{\circ}C$. Treatment samples were either packaged in an ethylene vinyl alcohol/polyethylene (EVOH/PE) copolymer film and stored at $5^{\circ}C$ (T1), and in a PA/PE film and stored at $-18^{\circ}C$ (T2). The initial total plate count (TPC) was 3.6 log cfu/g. In T1 samples, TPC and Brochothrix thermosphacta counts were increased, similar to those in C samples, whereas Pseudomonas spp. counts were significantly lower than those in C samples during storage. Over the storage period, the volatile basic nitrogen values increased most rapidly in C samples, followed by T1 and then T2 samples. The values of thiobarbituric acid reactive substances steadily increased in all samples during storage. The colour parameters were not significantly different among the samples during storage. T1 samples maintained sensory qualities in flavour and off-odour parameters for two days longer than C samples did. At day 12, T2 samples were evaluated as being below the marketability score of 5.0 for texture. In conclusion, using high oxygen barrier films like EVOH/PE copolymer for packaging Hamburg steaks could extend the sensory qualities in view of flavour and off-odour during chilled storage. However, frozen storage at $-18^{\circ}C$ is recommended when the storage period is extended beyond 14 days at $5^{\circ}C$.

• Journal of Soil and Groundwater Environment
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• v.11 no.1
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• pp.54-64
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• 2006

Chromated copper arsenate (CCA), a wood preservative, has been widely used to protect wood products from attacks by bacteria, fungi and insects. However, the use of CCA is currently forbidden or limited to some applications in many countries because the toxic elements (Cr, Cu, and As) of CCA are released into the environments during outdoor uses, which may cause adverse health effects on humans and ecological systems. This study was conducted to investigate the distributions of chromium, copper and arsenic in soils adjacent to two CCA-treated wood structures. In a 7 month old pond entry structure, ten surface soil samples (0-2.5 cm) were collected at lateral distances of 0, 0.5, and 1 m from the stairway, and nine surface soil samples were collected beneath the deck. Nine top soil samples were taken from a 2 year old sound barrier structure at lateral distances of 0, 1, and 2 m. Background surface soil samples were also collected from each structure. Samples were analyzed for some physicochemical properties such as pH, electrical conductivity, organic matter content, and soil texture. Following the extraction of the elements with a microwave digestion system, samples were analyzed for Cr, Cu, and As. The concentrations of the three elements in soils adjacent to the structures were significantly elevated compared to the background levels, indicating that the elements have been leached out of the structures. Released e1ements showed lateral concentration gradients within 1 m. The elevations of the three elements in soils underneath the deck did not seem different (background-corrected concentrations: Cr, 5.01 mg/kg; Cu, 5.50 mg/kg; As, 4.91 mg/kg), while the elements in soils near the sound barrier were elevated in the order of As>Cu>Cr with measured concentrations of 49.7, 44.7 and 52.5 mg/kg, respectively. Background As, Cu, and Cr concentrations near the sound barrier were 9.88, 30.8, and 46.5 mg/kg, respectively. These results showed that CCA constituents are released into the environment and it is suggested that risk assessment need to be conducted to investigate harmful effects of the released elements on humans and ecological systems.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.157-163
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• 2013

Cultured products (callus and exopolysaccharide) were obtained from suspension culture of Aloe vera callus, and the extracts of callus were further prepared with cold water or 60% ethanol solution. The ethanol extract of callus (AC) and exopolysaccharide (ACP) of 10 mg/mL exhibited the relatively higher suppression activity of 43.2-52.1% against hyaluronidase activity. Thus, their anti-inflammatory effects were further investigated using animal cell (Raw 264.7) in vitro. Though AC shows a slight suppression effect of cell survival rate (97%) using MTT assay in the presence of $400{\mu}g/mL$ AC- dimethyl sulfoxide (DMSO), cell growth promotion was observed in the other samples of lower levels. It indicates that the ethanol extract of Aloe callus rarely affect cell survival rate in the ranges ($200-400{\mu}g/mL$) used in the study. Using Griess reagent, the suppression of NO production by the aloe callus extract was analyzed by measuring the amount of the nitrite produced in Raw 264.7 culture activated by lipopolysaccharide (LPS). As a result, supplementation of AC-distilled water (DW) and AC-DMSO produced higher levels of NO than the positive control LPS. However, the NO suppression effect by ACP-DW was so intense that lower amount ($80-100{\mu}g/mL$) suppressed NO production to the level of the control. The effect was attributed to the expression of the iNOS. Then, Raw 264.7 cells were stimulated with the LPS and expression of COX-2 protein level was analyzed depending on the Aloe suspension culture product treatment. The results showed that the ACP-DW supplemented medium did not express COX-2 by itself, and LPS stimulated COX-2 expression was slightly decreased. On the other hand, realtime-PCR analysis of the expression of inflammatory cytokine showed that IL-$1{\beta}$ and TNF-${\alpha}$ expression was highly suppressed in the ACP- distilled water supplemented medium.

• Journal of The Korean Association For Science Education
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• v.38 no.4
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• pp.481-494
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• 2018

This study investigated elementary students' understanding of Earth revolution and its accompanied apparent motion of constellation in terms of spatial reasoning. We designed a set of multi-tiered constructed response items in which students described their own idea about the reason of consecutive movement of constellations for three months and drew a diagram about relative locations of the Sun, the Earth, and the constellations. Sixty-five sixth grade students from four elementary schools participated in the tests both before and after science classes on the relative movement of Earth and Moon. Their answers to the items were categorized inductively in terms of transforming frames of reference which are observed on the Earth and designed from the Space-based perspective. We analyzed those categories by the levels of spatial reasoning and depicted the change of students' levels between pre/post-tests so that we could get an idea on the preliminary developmental pathway of students' understanding of this topic. The lower anchor description was that constellations move around the Earth with geocentric perspective. Intermediate level descriptions were planar understanding of Earth movement, intuitive idea on constellation movement along with the Earth. Students with intermediate levels did not reach understanding of the apparent motion of constellations. As the upper anchor description students understood the apparent motion of constellations according to the Earth revolution and could transform their frames of reference between Earth-based view and Space-based view. The features as the case of evolutionary learning progressions and critical points of students' development for this topic were discussed.

• Toxicological Research
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• v.24 no.3
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• pp.175-182
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• 2008

DNA-dependent protein kinase(DNA-PK) is involved in joining DNA double-strand breaks induced by ionizing radiation or V(D)J recombination and is activated by DNA ends and composed of a DNA binding subunit, Ku, and a catalytic subunit, DNA-PKcs. It has been suggested that DNA-PK might be $2^{nd}$ upstream kinase for protein kinase B(PKB). In this report, we showed that Ser473 phosphorylation in the hydrophobic-motif of PKB is blocked in DNA-PK knockout mouse embryonic fibroblast cells(MEFs) following insulin stimulation, while there is no effect on Ser473 phosphorylation in DNA-PK wild type MEF cells. The observation is further confirmed in human glioblastoma cells expressing a mutant form of DNA-PK(M059J) and a wild-type of DNA-PK(M059K), indicating that DNA-PK is indeed important for PKB activation. Furthermore, the treatment of cells with doxorubicin, DNA-damage inducing agent, leads to PKB phosphorylation on Ser473 in control MEF cells while there is no response in DNA-PK knockout MEF cells. Together, these results proposed that DNA-PK has a potential role in insulin signaling as well as DNA-repair signaling pathway.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.35-42
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• 1970

Five samples of Korean native Maeju(fermented soy-bean mash) loaves which were collected each from Kyunggi, Chungchung, Kangwon, Cholla and Kyungsang-Do were examined for their fermenting microorganisms. The results of taxonomic and ecological studies of fermentation microorganisms in these Maeju loaves were as the fellows. (1) The fungus flora grew only is the outer layer of Maeju loaves. Miscellaneous molds, 3 species of Mucor, 2 species of Pericallium., one species each of Scopulariopsis and Aspergillus, were isolated. None of them seemed exclusively predominant to be able to designate as the ecologically significant. (2) The bacterial flora which consisted of two species, Bacillus subtilis and Bacillus pumilus were distributed uniformly in th a entire Maeju loaves. The inner parts of Maeju loaves were especially inhabited solely by these bacterial flora. Probably the Korean native Maeju fermentation could be characterized by these bacterial flora. A Staphylococcus species was also isolated probably as a casual contaminant. (3) The yeasts, Rhodotorula flava and Torulopsis dattila, were isolated from Maeju loaves though their ecological significance was not clear. (4) The ecological aspects of fermentation microbes in the outer and inner parts of Maeju loaves were apparently different, consequently different fermentation processes might have occurred in these two parts and it brought quite different final outlooks in the final matured Maeju loaves. The outer part, rather rigid and dry, retained the light brown color of boiled soy-bean; whereas the inner part, soft and sticky, showed dark brown color indicating severe chemical changes. (5) The aflatoxin producing mold, Aspergillus oryzae was isolated from one sample among 5 of Maeju loaves. In addition to the low probability of isolability from Maeju loaves samples, since this mold grew only in the outer layer of Maeju loaves with such a low population density, about $10^4/g$, perhaps the aflatoxin problem in Korean native soysauce may not be critical.

• Geophysics and Geophysical Exploration
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• v.1 no.2
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• pp.127-135
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• 1998

The Born approximation is widely used for solving the complex scattering problems in electromagnetics. Approximating total internal electric field by the background field is reasonable for small material contrasts as long as scatterer is not too large and the frequency is not too high. However in many geophysical applications, moderate and high conductivity contrasts cause both real and imaginary part of internal electric field to differ greatly from background. In the extended Born approximation, which can improve the accuracy of Born approximation dramatically, the total electric field in the integral over the scattering volume is approximated by the background electric field projected to a depolarization tensor. The finite difference and elements methods are usually used in EM scattering problems with a 2D model and a 3D source, due to their capability for simulating complex subsurface conductivity distributions. The price paid for a 3D source is that many wavenumber domain solutions and their inverse Fourier transform must be computed. In these differential equation methods, all the area including homogeneous region should be discretized, which increases the number of nodes and matrix size. Therefore, the differential equation methods need a lot of computing time and large memory. In this study, EM modeling program for a 2D model and a 3D source is developed, which is based on the extended Born approximation. The solution is very fast and stable. Using the program, crosshole EM responses with a vertical magnetic dipole source are obtained and the results are compared with those of 3D integral equation solutions. The agreement between the integral equation solution and extended Born approximation is remarkable within the entire frequency range, but degrades with the increase of conductivity contrast between anomalous body and background medium. The extended Born approximation is accurate in the case conductivity contrast is lower than 1:10. Therefore, the location and conductivity of the anomalous body can be estimated effectively by the extended Born approximation although the quantitative estimate of conductivity is difficult for the case conductivity contrast is too high.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.33-40
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• 2009

In field surveys using the dipole-dipole electrical resistivity method, we often encounter negative apparent resistivity. The term 'negative apparent resistivity' refers to apparent resistivity values with the opposite sign to surrounding data in a pseudosection. Because these negative apparent resistivity values have been regarded as measurement errors, we have discarded the negative apparent resistivity data. Some people have even used negative apparent resistivity data in an inversion process, by taking absolute values of the data. Our field experiments lead us to believe that the main cause for negative apparent resistivity is neither measurement errors nor the influence of self potentials. Furthermore, we also believe that it is not caused by the effects of induced polarization. One possible cause for negative apparent resistivity is the subsurface geological structure. In this study, we provide some numerical examples showing that negative apparent resistivity can arise from geological structures. In numerical examples, we simulate field data using a 3D numerical modelling algorithm, and then extract 2D sections. Our numerical experiments demonstrate that the negative apparent resistivity can be caused by geological structures modelled by U-shaped and crescent-shaped conductive models. Negative apparent resistivity usually occurs when potentials increase with distance from the current electrodes. By plotting the voltage-electrode position curves, we could confirm that when the voltage curves intersect each other, negative apparent resistivity appears. These numerical examples suggest that when we observe negative apparent resistivity in field surveys, we should consider the possibility that the negative apparent resistivity has been caused by geological structure.

• Clean Technology
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• v.24 no.3
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• pp.221-232
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• 2018

This research was conducted to evaluate the operational performance of landfill facility and landfill gas energy facility from the questionnaire survey. In order to evaluate overall operational performance, three types of weighting methods were applied to each technical, economical, and environmental item. There was no significant difference between an equal weighted method, a weighted method of 40% for technology, 30% for economy, and 30% for environment, and a weighted method of 30% for technology, 40% for economy, and 30% for environment. In technical performance, large and middle scales of landfill facilities showed higher scores of 14.8 ~ 19.7 and 14.3 ~ 19.0 than 9.8 ~ 13.0 of small scale one. In environmental performance, large, middle, and small scales of landfill facilities showed 21.3 ~ 23.7, 17.6 ~ 19.6, and 20.8 ~ 23.1 scores, respectively. However, in economical performance, there was significant difference between them with scale. Large and middle scales of landfill facilities showed higher scores of 22.0 ~ 29.3 and 20.5 ~ 27.3 than 6.0 ~ 8.0 of small scale one. As a result of evaluation for landfill gas energy facility, large scale facility showed 19.2 ~ 25.6 and 17.8 ~ 23.7 scores in technical performance and 23.1 ~ 25.7 and 21.3 ~ 23.7 scores in environmental performance, respectively. However, in economical performance evaluation, large scale of landfill gas energy facility showed relatively higher of 27.8 ~ 33.3 score than 18.8 ~ 25.1 of small scale one. From these results, it was shown that economy evaluation heavily effect on the operational performance of landfill facility and landfill gas energy facility compared to technology and environment evaluation.

• KSBB Journal
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• v.23 no.6
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• pp.463-469
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• 2008

During the last decade, monacolin-K biosynthesized by fermentation of red yeast rice (Monascus strains) was proved to have an efficient cholesterol lowering capability, leading to rapid increase in the market demand for the functional red yeast rice. In this study, the production medium composition and components were optimized on a shake flask scale for monacolin-K production by Monascus pilosus (KCCM 60160). The effect of three different soybean flours on the monacolin-K production were studied in order to replace the nitrogen sources of basic production medium (yeast extract, malt extract and beef extract). Among the several experiments, the production medium with dietary soybean flour to replace a half of yeast extract was very good for monacolin-K production. Plackett-Burman experimental design was used to determine the key factors which are critical to produce the biological products in the fermentation. According to the result of Plackett-Burman experimental design, a second order response surface design was applied using yeast extract, beef extract and $(NH_4)_2SO_4$ as factors. Applying this model, the optimum concentration of the three variables was obtained. The maximum monacolin-K production (369.6 mg/L) predicted by model agrees well with the experimental value (418 mg/L) obtained from the experimental verification at the optimal medium. The yield of monacolin-K was increased by 67% as compared to that obtained with basic production medium in shake flasks.