• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.209-218
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• 1987

Leptospira interrogans, the causative organism of leptospirosis, is characterized by a fine helical morphology, and the helix is almost always right-handed. However, one of the striking features of recent isolates of L. interrogans in Korea was the heterogeneity in their morphology. Even under optimal culture conditions($30^{\circ}C$, EMJH medium), rods, spiral forms with right or left-handed helices, and even spherical forms of L. interrogans were present. Although the literature notes the presence of left-handed helices, long rods, and spherical forms in cultures of L. interrogans isolates, little is known about the cause of this morphologic heterogeneity. In an attempt to answer this question, this study was initiated to examine the effects of culture conditions, especially temperature and medium, on the morphology of L. interrogans. Four temperatures($5^{\circ}C$, $15^{\circ}C$, $30^{\circ}C$, and $37^{\circ}C$) and two types of media(Fletcher and EMJH) were used; one strain from Korean isolates and L. interrogans serovar canicola obtained from the Pasteur Institute(Paris, France) were employed throughout the study. The findings are as follows: 1. The L. interrogans isolated in Korea(UM-19) had a larger cell diameter($0.25{\sim}0.30\;{\mu}m$: $0.10{\sim}0.15\;{\mu}m$), and helix diameter($0.10{\sim}0.60\;{\mu}m$: $0.10{\sim}0.15\;{\mu}m$) than that obtained from the Pasteur Institute, but they varied in their distances between the helices($0.31{\sim}1.00\;{\mu}m$: $0.50{\sim}0.70\;{\mu}m$). 2, When UM-19 was grown at $37^{\circ}C$ after months or longer preincubation at $5^{\circ}C$ or $15^{\circ}C$, the majority of the organisms were spiral forms; however, they became rods when subcultured at $30^{\circ}C$ or $37^{\circ}C$. No significant morphological differences were found between Fletcher and EMJH media. 3. When L. interrogans serovar canicola was subcultured more than ten times at $37^{\circ}C$, some of the organism lost their motility as well as the hooks at either one or both ends, but only in Fletcher medium. The number of variants increased with the frequency of subculturing. These findings suggested that L. interrogans strain (UM-19) is different, in their morphology, from that of the Pasteur Institute, and its various morphologies may represent stages of the life cycle and vary with incubation temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.727-733
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• 2011

A new Korean standard for the determination of Cr(VI) in soils has been officially published as ES 07408.1 in 2009. This analytical method is based on the hot alkaline digestion and colorimetric detection prescribed by U.S. EPA method 3060A and 7196A. The hot alkaline digestion accomplished using 0.28 M $Na_2CO_3$ and 0.5 M NaOH solution (pH 13.4) at $90{\sim}95^{\circ}C$ determines total Cr(VI) in soils extracting all forms of Cr(VI), including water-soluble, adsorbed, precipitated, and mineral-bound chromates. This aggressive alkaline digestion, however, proved to be problematic for certain soils which contain large amounts of soluble humic substances or active manganese oxides. Cr(III) could be oxidized to Cr(VI) by manganese oxides during the strong alkaline extraction, resulting in overestimation (positive error) of Cr(VI). In contrast, Cr(VI) reduction by dissolved humic matter or Fe(II) could occur during the neutralization and acidic colorimetric detection procedure, resulting in underestimation (negative error) of Cr(VI). Futhermore, dissolved humic matter hampered the colorimetric detection of Cr(VI) using UV/Vis spectrophotometer due to the strong coloration of the filtrate, resulting in overestimation (positive error) of Cr(VI). Without understanding the mechanisms of Cr(VI) and Cr(III) transformation during the analysis it could be difficult to operate the experiment in laboratory and to evaluate the Cr(VI) results. For this reason, in this paper we described the theoretical principles and limitations of Cr(VI) analysis and provided useful guidelines for laboratory work and Cr(VI) data analysis.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.706-714
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• 2021

Chemical scavenging of reactive oxygen species (ROS) is considered a major mechanism of antioxidant effects, but preventing ROS generation can be more efficient in attenuating oxidative damage. In this study, the extracts of plants, Solanum lycopersicum, Ailanthus altissima, Equisetum arvense, and Oenothera biennis, were tested to determine whether their antioxidative effects are driven by the prevention of superoxide generation from mitochondria, a major ROS generator. While all the extracts efficiently attenuated the elevation of ROS levels in human fibroblasts and inflammation-induced mice, those of S. lycopersicum, A. altissima, and O. laciniata only suppressed mitochondrial ROS generation and reduced levels of lipofuscin and lipid peroxidation. Furthermore, the extracts of A. altissima and O. laciniata extended the lifespan of fruit flies. Our results suggest that plant extracts with anti-oxidative effects differ in their ability to prevent ROS generation, which may be associated with the attenuation of oxidative damage in cells and animal tissues.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.68-77
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• 2021

In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.196-205
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• 2021

As industrial safety increases, various industrial accident prevention technologies using smart factory technology are being studied. However, small and medium enterprises (SMEs), which account for the majority of industrial accidents, are having difficulties in preventing industrial accidents by applying these smart factory technologies due to practical problems. In this study, customized monitoring and warning systems for each type of industrial accident were developed and applied to the actual field. Through this, we demonstrated industrial accident prevention technology through appropriate smart factory technology used by SMEs. A customized monitoring system using vision, current, temperature, and gas sensors was established for the four major disaster types: worker body access, short circuit and overcurrent, fire and burns due to high temperature, and emission of hazardous gas. In addition, a notification method suitable for each work environment was applied so that the monitored risk factors could be recognized quickly, and real-time data transmission and display enabled workers and managers to understand the disaster risk effectively. Through the application and demonstration of these appropriate smart factory technologies, the spread of these industrial safety technologies is to be discussed.

• Journal of Korean Library and Information Science Society
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• v.54 no.3
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• pp.81-104
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• 2023

This study is a case study in which collection performance evaluation was attempted using key performance indicators presented by EBSM or collectionHQ, taking three public libraries located in Geumjeong-gu, Busan as examples. Focusing on the collection performance evaluation, which evaluates the performance of the collection, not only the evaluation of individual libraries, but also the differences in the evaluation results of libraries were reviewed. The key performance indicators used are grubby items, dead items, popular author provision, popular subject provision, overstocked subject areas and understocked subject areas. The main analysis results are as follows. First, in the evaluation of the grubby items, the ratio of grubby items out of all items in all three libraries was low. Second, in the case of all dead items, the ratio was high in all three libraries, It exceeded the base value suggested by collectionHQ. Third, the Top 10 popular authors were identified, and there were differences among libraries. Fourth, in the evaluation of provision of popular subject areas, all three libraries had almost no popular subject areas. Fifth, in the evaluation of overstocked subject areas, there was no overstock at Geumsaem Library, but many at Geumjeong Library and Seodong Library. Sixth, in the subject area evaluation of understocked inventory, only Geumsaem Library showed a lack of inventory.