• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.51-60
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• 2023

The foodborne illness is the important public health concerns, and the livestock feces are known to be one of the major reservoirs of foodborne pathogens. Also, it was reported that 45.5% of foodborne illness outbreaks have been associated with the animal products contaminated with the livestock feces. In addition, it has been known that the persistence of a pathogens depends on many potential virulent factors including the various virulent genes. Therefore, the first step to understanding the public health risk of livestock feces is to identify and describe microbial communities and potential virulent genes that contribute to bacterial pathogenicity. We used the whole metagenome shotgun sequencing to evaluate the prevalence of foodborne pathogens and to characterize the virulence associated genes in pig and chicken feces. Our data showed that the relative abundance of potential foodborne pathogens, such as Bacillus cereus was higher in chickens than pigs at the species level while the relative abundance of foodborne pathogens including Campylobacter coli was only detected in pigs. Also, the microbial functional characteristics of livestock feces revealed that the gene families related to "Biofilm formation and quorum sensing" were highly enriched in pigs than chicken. Moreover, the variety of gene families associated with "Resistance to antibiotics and toxic compounds" were detected in both animals. These results will help us to prepare the scientific action plans to improve awareness and understanding of the public health risks of livestock feces.

• Journal of Space Technology and Applications
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• v.3 no.1
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• pp.26-43
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• 2023

As Korean first lunar probe, Danuri, succeeded in entering lunar orbit, Korean new space exploration plans such as Mars exploration can be expected. Korean space exploration payload is developed only in a limited field, so there is a need to create a new space exploration payload. In foreign countries, there is a mass spectrometer as a basic equipment for space exploration, and it is a very useful payload that encompasses the exploration of life through the analysis of organic matter as well as the observation of the atmosphere and volatile substances of the exploration target. However, Korea has never developed a mass spectrometer payload for space exploration, so it is necessary to secure technology in preparation for future space exploration. Before that, we look at the scientific achievements of foreign mass spectrometer payloads for space exploration and identify trends.

• Journal of Space Technology and Applications
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• v.3 no.1
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• pp.86-99
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• 2023

The mass spectrometer, being an essential scientific instrument for uncovering the origin of the solar system and life, has been used since the early 1970s on board spacecraft to obtain information of neutral and ionized elements in the atmosphere and surface of the moon, planets, asteroids, and comets. According to the 4th Basic Plan for the Promotion of Space Development (2023-2027), Korea plans to conduct lunar landing in 2032 and Mars landing in 2045 as the core goals of the plan and focuses on developing the technologies required for unmanned robotic exploration missions. In this regard, it is crucial to develop the technology of a mass spectrometer, which is the most fundamental payload for space exploration for maximized scientific achievements, however never tried before in any domestic space missions. We describe in this paper the principle of a domestically developed quadrupole mass spectrometer, its prototype model, and the test results of its performance. We conclude this paper with intended future improvements.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.186-194
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• 1986

In an attempt to find better ways to relate growth with temperature and to estimate maturity differences in corn (Zea mays L.), various formulas of computing Growing Degree Days (GDD) were evaluated. Utilizing data from 17 plantings of a single cross, Suweon 19, over a 3 year period, 24 different methods of computing GDD were compared for their ability to reduce variations over different plantings. The best equation was to compute GDD with a base temperature of 10$^{\circ}C$ and an optimum of 30$^{\circ}C$. The excess temperature above 30$^{\circ}C$ was subtracted to account for high temperature stress. GDDs required for emergence and silking of Suweon 19 were 64${\pm}$12$^{\circ}$ and 794${\pm}$19$^{\circ}$, respectively. Based on these GDD values, emergence and silking dates could be estimated with a variation less than 3 days. The observed and estimated number of days from planting to emergence and silking were not significantly different.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.212-220
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• 1995

The optimum seeding date and the suitable seeding period for puddled drill seeding of rice at southern plain area were determined by using Sinunbongbyeo (early maturing variety), Hwaseongbyeo(medium maturing var.) and Dongjinbyeo (late medium maturing var.) at National Honam Agricultural Experiment Station from 1993 to 1994, Seedling stand was decreased significantly at seeding on April 25 in all varieties, Threshold seed-ing dates for stable ripening was estimated as June 10 in Sinunbongbyeo, May 31 in Hwaseongbyeo and May 25 in Dongjinbyeo, The 1,000 grain weight and the ripened grain rate were highest at seed-ing on May 10 or May 25 in all varieties, and decreased significantly at seeding on June 25 in Sinunbongbyeo and seeding after June 10 in Hwaseongbyeo and Dongjinbyeo, The optimum average air temperature for 40 days after heading was 22.6$^{\circ}C$ for highest ripening rate and 22.0$^{\circ}C$ for heaviest 1,000 grain weight. The optimum seeding date for highest yield was May 9 in Dongjinbyeo, May 13 in Hwaseongbyo and May 15 in Sinunbongbyeo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.629-636
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• 1995

This study was carried out to clarify the proper nitrogen application methods under the different seedling density in puddled-soil drill seeding of rice. Seedling density was adjusted as 30, 60, 90, 120 and 150ea/$m^2$ just after emergence and nitrogen was applied with five methods including conventional respectively. The maximum tillering stage was shorten as the seedling density was increase but decreased the percentage of productive tillers. Lodging was occurred serverely as the seedling was more than 120ea/$m^2$, when nitrogen was applied at panicle initiation stage. Grain yield wasn't significantly different among seedling densities when it was more than 60ea/$m^2$, but the density of 30ea/$m^2$ was decreased. It wasn't significantly different among the nitrogen application methods when it was more than 90ea/m, but was higher at early application of tillering fertilizer (T$_2$) than conventional method when the seedling density was less than 60ea/$m^2$. Supposing that the yield of reseeding is the same as optimum seedling density, minimum seedling density needs for reseeding would be less than 55 ea/$m^2$ as the aspect of income allowed for managing expense.

• Journal of Environmental Health Sciences
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• v.48 no.6
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• pp.298-305
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• 2022

Background: The concentration of air pollutants as measured by the Air Quality Monitoring System (AQMS) is not an accurate population exposure level since actual human activities and temporal and spatial variability need to be considered. Therefore, to increase the accuracy of exposure assessment, the population should be considered. However, it is difficult to obtain population data due to limitations such as personal information. Objectives: The existing population defined in this study is the number of people in each region's grid. The purpose is to provide a methodology for evaluating exposure to PM_2.5 through existing population data provided by the National Geographic Information Institute. Methods: The selected study period was from October 26 to October 28, 2021. Using PM_2.5 concentration data measured at the Sensor-based Air Monitoring Station (SAMS) installed in Guro-gu and Wonju-si, the concentration for each grid was estimated by applying inverse distance weights through QGIS version 3.22. Considering the existing population, population-weighted average concentration (PWAC) was calculated and the exposure level of the population was compared by region. Results: The outdoor PM_2.5 concentration as measured through the SAMS was high in Wonju-si on all three days. Wonju-si showed an average 22% higher PWAC than Guro-gu. As a result of comparing the PWAC and outdoor PM_2.5 concentration by region, the PWAC in Guro-gu was 1~2% higher than the observed value, but it was almost the same. Conversely, observations of Wonju-si were 10.1%, 11.3%, and 8.2% higher than PWAC. Conclusions: It is expected that the Geographic Information System (GIS) method and the existing population will be used to evaluate the exposure level of a population with a narrow activity radius in further research. In addition, based on this study, it is judged that research on exposure to environmental pollutants and risk assessment methods should be expanded.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.227-232
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• 1983

Two single cross maize hybrids planted on May 4 and 25 and June 15, 1982 were grown at 40,000:55,000 70,000 and 85,000 plants per hectare to evaluate plant density effect on growth and grain yield at different planting dates. Two hybrids with different leaf angle (Suweon 19 with horizontal leaves and Suweon 58 with erect leaves) and the same maturity were used. The number of days from planting to silking varied from 74 to 58 days as planting was delayed from May 4 to June 15. However, growing degree days from planting to silking was about $810^{\circ}C$ regardless planting dates. Grain yields of two hybrids were significantly decreased as planting was delayed. The number of ears per 100 plants and the number of kernels per ear of two hybrids were linearly decreased with increasing plant density. The optimum plant density for Suweon 19 estimated by Duncan's method was about 55,000 plants hectare for May 4 and 25 plantings and decreased to 32,000 plants/hectare for June 15 planting. The optimum density for Suweon 58 was estimated to be about 71,000 plants/hectare for May 4 planting and 54,000 plants/hectare for May 25 planting, respectively.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.5-13
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• 2007

The performance of innovative prestressed support (IPS) earth retention system applied in soft clay was investigated and presented. The IPS wale system provides a high flexural stiffness to resist the bending by lateral earth pressure, and transfers lateral earth pressure to strut supports. The IPS wale system provides a larger spacing of support than conventional braced and anchored systems. The IPS earth retention system was selected for temporary earth support in a building construction in North Busan area. The excavation was made 28.8 m wide, 52.0 m long, and 16.1 m deep through loose fill to soft clay. The IPS system consists of 650 mm thick slurry walls, and five levels of IPS wales and struts. Field monitoring data were collected including wall deflections at six locations, ground water levels at four locations, IPS wale deflections at thirty locations, and axial loads on struts at twenty locations, during construction. The IPS earth retention system applied in soft clay performed successfully within a designed criterion. Field measurements were compared with design assumptions of the IPS earth retention system. The applicability and stability of the IPS earth retention system in soft clay were investigated and evaluated.

• Korean Journal of Environmental Biology
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• v.41 no.1
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• pp.1-13
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• 2023

Broad bean wilt virus 2 (BBWV2) is a species in the genus Fabavirus and family Secoviridae, which is transmitted by aphids and has a wide host range. The BBWV2 genome is composed of two single-stranded, positive-sense RNAs, RNA-1 and RNA-2. The representative symptoms of BBWV2 are mosaic, mottle, vein clearing, wilt, and stunting on leaves, and these symptoms cause economic damage to various crops. In 2019, Perilla fructescens leaves with mosaic and yellowing symptoms were found in Geumsan, South Korea. Reverse-transcription polymerase chain reaction (RT-PCR) was performed with specific primers for 10 reported viruses, including BBWV2, to identify the causal virus, and the results were positive for BBWV2. To characterize a BBWV2 isolate (BBWV2-GS-PF) from symptomatic P. fructescens, genetic analysis and pathogenicity tests were performed. The complete genomic sequences of RNA-1 and RNA-2 of BBWV2-GS-PF were phylogenetically distant to the previously reported BBWV2 isolates, with relatively low nucleotide sequence similarities of 76-80%. In the pathogenicity test, unlike most BBWV2 isolates with mild mosaic or mosaic symptoms in peppers, the BBWV2-GS-PF isolate showed typical ring spot symptoms. Considering these results, the BBWV2-GS-PF isolate from P. fructescens could be classified as a new strain of BBWV2.