• Journal of Biosystems Engineering
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• v.30 no.2 s.109
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• pp.121-126
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• 2005

In this study, a commercial electronic nose system was used to detect contamination of Salmonella bacteria. Odors from growth media contaminated with Salmonella typhimurium, Salmonella enteritidis, or Escherichia coli were collected and analyzed to evaluate a possibility of rapid detection of pathogen. Odor chromatograph showed that S. typhimurium, S. enteritidis, and E. coli had 7,6, and 9 main peaks, respectively. Retention time and intensity of the peaks were distinct for different bacteria species. Principal component analysis (PCA) were also performed to clarify odor differences. Analysis results showed that the odors for uncontaminated growth medium were differently grouped from the odors of contaminated one. The odor from the bacteria growth identified with two principal components, PC 1 and PC2. In PCA figures, odor groups were moved from left to right of PC 1 with elapse of the bacteria growth time. The electronic nose system could detect odors of S. typhimurium, S. enteritidis, E. coli when their concentration were $1.85\times10^6\;cfu/g,\;2.25\times10^6\;cfu/g,\;and\;1.8\times10^5 cfu/g$, respectively.

• Analytical Science and Technology
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• v.8 no.4
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• pp.561-568
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• 1995

Two methods, precipitation and ultrafiltration, were applied in order to recover platinum group metals(PGM) by complexing them with water-soluble polyelectrolytes, e.g., polyethyleneimine [PEl], poly(2-vinylpyridine) [2-PVP], poly (4-vinylpyridine) [4-PVP], and poly (styrene sulfonic acid) [PSSA]. In the precipitation method, the PGM-polyelectrolyte complex that was formed by mixing first with polybase, e.g.,4-PVP at pH 1 was precipitated by further mixing with polyacid, e.g., PSSA. However, the recovery of PGM obtained by this method was not quantitative(less than 70%). The "sandwiching" binding between the metal anions and two polyelectrolytes was examined by X-ray photoelectron spectroscopy(XPS). The XPS studies indicated that the PGM atom was bound with the acdic and basic polyelectrolyte via its oxygen and nitrogen atom, respectively. The recovery of PGM using polyelectrolyte was further studied by ultrafiltration methods as follows : The PGM ions, eomplexed at pH 1 with polyelectrolyte, allowed the applicntion of membrane filtration by virtue of the great differences in molecular weights between PGM and other low molecular weight species. By applying this method, Pd and Pt (ca. $10^{-4}M$) were selectively separated almost quantitatively from coexisting metal ions, e.g., $Cu^{2+}$ and $Ni^{2+}$. The EPR spectra and viscosity measurements indicated that these polyelectrlytes were not bound to $Cu^{2+}$ and $Ni^{2+}$ ions at this pH, which provided the basis for selective separation of PGM(Pd, Pt and Rh) from these coexisting ions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.341-347
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• 2007

Chinese milk vetch (CMV) is a winter legume that is commonly used as cover crop in Korea. Kill date of cover crop for addition into soil affects N content in cover crop and N availability in soil. This study was conducted to evaluate the effect of CMV as green manure cover crop according to kill dates before growing corn without artificial fertilizer. Top of CMV cut three times on 13 April, 27 April, and 11 May were added into soil at a rate of 600 kg per 10a. Sugar content in CMV litter was persistently decreased from mid-April to late-May. The decrease of sugar content might be due to the transformation into starch and/or other storage or structural constituents. The decreased amount of sugars was greater than 12% and the increased amount of starch was less than 0.2%. Concentration of $NH_4^+$ in soil treated by CMV litter cut on May 11 was slightly higher than that in the treatment with early-cut (April 13) CMV, the concentration at 28 and 49 DAT (days after treatment) was higher in the treatment with late-cut CMV litter. Regardless of cut (kill) date of CMV, the phosphatase activity in the treatment of CMV litter was higher compared to the untreated control. Soil dehydrogenase activity was increased steadily by addition of CMV litter implying total microbial activities in the soil were increased. Our results demonstrate that the status of cover crop species at kill date is an important factor influencing soil enzyme activities derived from microorganisms. Therefore, the optimal kill date of cover crop should be examined to improve the efficiency of cover crop as green manure crop regarding the practical sequence in cropping system.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.94-98
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• 1998

Agaricus blazei Murill, a mushroom which is well known as a potent antitumor agent, contains abundant pharmaceutical substances. To identifY the major components of Agaricus blazei Murill fruiting bodies cultivated in a Korean local farm was analyzed. There were not large differences in chemical compositions of inorganic substances, carbohydrates, amino acids and fatty acids between Agaricus blazei Murill fruiting bodies cultivated in Korea and those in Japan. However, carbohydrate composition was significantly lower in Agaricus blazei Murill of Korea compared to those of Japan. Total amino acid contents were 280.75 mg% in Agaricus blazei Murill fruiting bodies. Sixteen species of amino acid were identified by high performance liquid chromatography except cysteine. Linoleic acid, the most abundant fatty acid contained in Agaricus blazei Murill fruiting bodies, was estimated to be 78.3% of total fatty acids.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.147-152
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• 1999

The efficiency of the OECD MITI(I) test which is designated as a standard method for measuring the biodegradability of chemicals by the Korean Ministry of Environment was evaluated and compared with those of two other OECD ready biodegradability tests： the manometric respirometry test and the closed bottle test. All the tests were applicable to a wide variety of organic chemicals and there were no significant differences in biodegradation rates of eight test chemicals and a reference chemical with three methods. However, the MITI(I) test had unnecessary expense and complexity in preparation of a mixed inoculum. Decrease in bacterial diversity during pre-conditioning of the inoculum for 1 month was observed and therefore the mixed inoculum did not ensure the presence of a variety of species in the test. Based on the simplicity, cost-effectiveness and reproducibility of the test procedure, it is considered that the manometric respirometry test is the most adequate method which can replace the MITI(I) test method.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.50-61
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• 2008

Environmental factors and phragmites growth properties at various habitats in Eulsukdo ecological park were investigated to understand major factors affecting phragmites distribution in constructed wetlands. Although phragmites is very important species in wetland ecosystem, it should be controlled to prevent excessive expansion within the restricted park area. The results showed that phragmites dominant sites have the highest LAI among other emerged plants habitats and could adversely affect for waders habitats. Phragmites were also found at the areas with wide ranges of water-depth than other plants, and showed phragmites could be favored for occupying the newly constructed wetlands like Eulsukdo ecological park. The results showed difference in soil redox potential between phragmites dominant and non-dominant sites. Because soil redox potential is affected by wetland hydrology like flooding duration, control of wetland hydrology should be considered for creation and management of constructed wetlands. The results also showed that differences in soil cation exchange capacity, soil salinity, soil organic matter content and site inclination between phragmites dominant and non-dominant sites as well as brackish and freshwater areas. Those abiotic factors can be important considerations for the sustainable wetland management especially for the phragmitest managements in the ecological park.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.2
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• pp.114-123
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• 2010

The Environmental Conservation Value Assessment Map (ECVAM) is a five grade assessment map created with nationally integrated environmental information and environmental values. The map is made through the evaluation of 67 items, including greenbelt area and bio-diversity. The ECVAM assesses the stability of the community using forest maps. However, the existing assessment method is problematic because the assessment grades are evaluated using higher than practical values; in part because it uses even-valued overlay and minimal indicator methods. This study was performed in order to suggest an integrated assessment method that could complement the stability evaluation based on existing methods. Accordingly, this study added forest type information, including whether the forest was natural or artificial, to the overlay method using forest diameter maps and forest density maps. As a result, the proposed ECVAM indicated a drastic grade change. After applying the method in South Korea, Grade I areas decreased 12.1%, from 52.6% to 40.6%, Grade II areas increased 11.9%, from 17.4% to 29.2%, and Grade III areas increased 0.2%, from 17.1% to 17.4%, respectively. From the results of the field survey, we found differences between natural forest and planted forest with regard to the number of mortality, species of shrubs, and vine cover. This means that natural forests are more stable than planted forests. This study suggests an improved assessment methodology to complement the existing EVCAM method. The results are expected to be used in environmental evaluations and forest conservation value assessments in ecology and environmental fields.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.288-294
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• 1994

Seedling vigor of introgressive hybrids between birdsfoot refoil 'MO-20"(Lotus corniculatus) used as the maternal parent and tetraploid(2n=4x=24)accession PI302921 narrowleaf trefoil(Lotus corniculatus L.), and parents were compared in terms of dry matter accumulation , net photosynthetic rate, dark respiration rate, and growth analysis. The hybrids showed better seedling vigor than PI302921 as they had lower dark respiration rate and higher relative growth rate (RGR) than PI302921. Hybrids grew faster than MO-20, but there was not significant difference between them. Net photosynthesis per unit area increased during three weeks after emergence without difference among the entries, then decreased sharply with leaf age and shading marking much differences among entries Dark respiration rate was very high just after emergence, after which it decreased rapidly until it reached a stable level at 1 week through 3 weeks of age, and then dropped again. In general, dark respiration, photosynthesis, and seedling growth of the hybrid was similar to those if MO-20. Although there are some reports about interspecific hybrids of Lotus species, it still remains as a new area for genetic improvement of seedling vigor of L. corniculatus.atus.

• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.129-132
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• 2010

The epidemiology of reported food-borne disease (FBD) outbreaks from 2001 to 2008 in Korea nd Japan were compared in this study. The outbreak rate of FBD in Japan was significantly higher although the average umber of patient in each outbreak in Korea was much higher. In both countries, summer was the season when most FBD outbreaks occurred. The comparison study revealed that FBD outbreaks in spring were more frequent in Korea, and outbreaks in winter were more frequent in Japan. Almost half of FBD outbreaks were observed at restaurants in both countries while FBD outbreaks at schools and work-places in Korea were much higher than in Japan. The most frequent cause of bacterial FBDs in Korea was pathogenic Escherichia coli followed by Salmonella species. On the other hand, Campylobacter jejuni was the most frequent source of bacterial FBDs in Japan. Norovirus, which is elated to uncontrolled hand hygiene and involvement of ill food workers, was the main cause of viral FBDs in both countries. In conclusion, there are common epidemiological characteristics as well as several differences in FBD outbreaks of Korea and Japan. These are suggested to be originated from the characteristic of climate, food sources, and life styles in two countries. Establishment of stricter control and surveillance system for FBD outbreaks are required or prevention and reduction of FBD outbreaks in both countries.

• The Korean Journal of Food And Nutrition
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• v.31 no.2
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• pp.229-235
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• 2018

Ramie (Boehmeria nivea M.) has been used for fiber materials in Korea traditionally, but in recent years, the concern with ramie leaves for the food industry such as tteok (a kind of Korean rice cake) industry has been increasing, so a study for eatable ramie is required for the expansion of ramie consumption. Moreover, the ramie varieties for the food industry are not established, so the natural species are cultivated in general; therefore, it is very important to select the ramie varieties for the food industry such as rice cakes, tea, beverage and so on. This study was undertaken to compare the physiochemical properties among 9 ramie lines selected in the Yeonggwang-gun Agricultural Technology Center to select the eatable ramie varieties for the food industry. The contents of the protein among 9 ramie lines was 6.21~7.56% and had the highest content in the YG55. The folic acid (folate) and vitamin C content had varying differences among the 9 lines; the content of folate showed $771.52{\sim}1,978.84{\mu}g%$, that of vitamin C showed 149.42~275.34 mg%. The ACE inhibitory activity appeared to be the highest in YG88 (21.5%) among the 9 ramie varieties tested.