• Journal of Food Hygiene and Safety
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• v.11 no.4
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• pp.287-290
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• 1996

To control the maximum residue level (MRL) for sulfamethazine (SMZ) residues in pork tissue, a microbial inhibition method is a regulatory screening assay method in Korea. Microwell plate-based competitive enzyme immunoassay (ELISA) kit is avalable for routine screening of SMZ residues in pork tissue. One ELISA kit is evaluated. Phosphate buffer extracts of samples fortified with SMZ at 0, 1, 5, and 10 ng/g were used in a recovery test of the kit. Market pork samples were assayed by the kit. Recovery of sulfamethazine was 104% at 10 ng/g. Intraassay variations and interassay variations for the kit were 7.70% and 5.76%, respectively. Concentration causing 50% inhibition of color development compared with blanks was 16.4ng. The violative pork samples with over MRL (0.1 $\mu\textrm{g}$/g) was 4 of 32 cases (12.5%) by used ELISA kit. This result indicates a possibility of the ELISA kit for screening test of SMZ residues in pork tissue, and still needs a comfirmatory assay for mandatory purposes.

• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.305-309
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• 2001

Thirty-day-old rice seedlings, IR-20 variety were transplanted into the experimental plots and were sprayed with endosulfan (35% EC) after 52 days at the rate of 0.64 kg a.i/ha. Residues of endosulfan in the plant, soil, and water were found to decrease steadily upto 15 days. A second application of the pesticide was made on the 31st day and the plant was harvested on 56th day after the first application. The residue level on hay and grains was 0.7 ${\mu}g/g$. This level is seven times higher than FAO/WHO-prescribed tolerance level of 0.1 ${\mu}g/g$. Metabolites of endosulfan were traced out in plants, soil, and water during the pre- and post-harvest period.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.63-69
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• 2012

The rice husk is one of the major agricultural residue in KOREA. In this paper, the effects of various pulping conditions on the properties of rice husk pulp and handsheets made of rice husk fiber were evaluated in order to utilize the rice husk as an alternative source for wood pulp. Two typical alkali pulping, such as soda pulping and Kraft pulping were applied with various conditions of the pulping processes. The higher effective alkali and higher pulping temperature resulted in the higher efficiency in removal of lignin and ash, which leaded to the higher strength properties of handsheets made of rice husk fiber, but the lower yield of rice husk pulp. The better efficiency in production of rice husk pulp and the stronger handsheets were obtained by the Kraft pulping.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.327-333
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• 1995

The sludge application increased the panicle number per plant and number of spikelets per panicle, resulting in an increase in yield by 10% at Cheongdo, 15% at Chinju and 7% at Yeocheon. With the sludge application (3% w/w), $SiO_2$ content of brown rice was significantly increased. The sludge aplied up to 34.8 ton per hectare increased pH, calcium, and potassium in paddy soils, the application of the sludge to reclaimed saline soil at Yeocheon needs to be reevaluated since the sludge increased soil pH to 7.2 and aggravated drainage.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.43-52
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• 2016

The coniferous fallen leaf is one of the major forestry residues. Since the coniferous fallen leaf would not be easily decayed, the large amount of the coniferous fallen leaves in forestry could be the source of forest fire. The applicability of the fallen leaves to the pulp mold were evaluated for developing new utilization of coniferous fallen leaves. The morphological properties and the chemical composition of the fallen leaves of Pinus densiflora and Pinus koraiensis were evaluated by the comparison with those of fresh leaves. The applicability of the coniferous fallen leaves to the pulp mold and the effects on the pulp mold properties including the scent diffusion were investigated. The fallen leaves showed the shrunk structure by losing the hot water extract component, which leaded to better grinding properties than that of fresh leaves. The pulp mold with fallen leaves showed higher strength properties than the pulp mold with fresh leaves. Although the scent of the pulp mold with fresh leaves was stronger, the pulp mold with fallen leaves had coniferous scent too. The application of fallen leaves to pulp mold for the functional properties could be possible by improving the mechanical properties and the scent lasting treatments.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.1
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• pp.37-42
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• 2005

We cloned the $\beta$-tubulin genes from the wild type strain and two benomyl-resistant mutants of Metahizium anisopliae and determined their nucleotide sequences. A $\beta$-tubulin encoding 448-residue protein from wild type M. anisopliae shows strong homology to other $\beta$-tubulins. The coding region is interrupted by four introns. Comparisons of intron position between the M. anisopliae gene and other fungal $\beta$-tubulin genes show considerable positional conservation. The mutations responsible for benomyl resistance were determined in two spontaneous mutants, 8-18 and 8­19. One mutant 8-18 substituted glutamate for aspar­agine at position 33 and lysine for glutamine at position 134. The other mutant 8-19 showed alterations at three positions of $\beta$-tubulin arginine for tryptophan at position 21, lysine for asparagine at position 33, and phenylalanine for leucine at position 240. These data suggest that regions of $\beta$-tubulin containing amino acids 21, 33,134, and 240 interact to form the binding site of benomyl.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4265-4269
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• 2011

A method based on ethyl acetate extraction and gas chromatography with tandem mass spectrometry was developed for determining tetraconazole residues in fruits and vegetables. A 10 g homogenized sample was mixed with 10 mL ethyl acetate, shaken vigorously for 3 min, stored at $-20^{\circ}C$ for 15 min, and then vortexed vigorously for 1 min; 1 g NaCl and 4 g anhydrous $MgSO_4$ were added. The clean-up was carried out by applying dispersive solid-phase with 150 mg $MgSO_4$and 50 mg primary secondary amine. Three precursor product ion transitions for tetraconazole were measured and evaluated to provide the maximum degree of confidence. Average recoveries in fruits and vegetables at three levels (0.005, 0.05 and 0.5 mg/kg) ranged from 85.53% to 110.66% with relative standard deviations ($RSD_r$) from 1.3% to 17.5%. The LODs ranged from 0.002 to 0.004 ${\mu}g$/kg, and LOQs ranged from 0.006 to 0.012 ${\mu}g$/kg. This method was also applied to determine tetraconazole residue in cucumber dissipation experiment under field conditions. The half-lives of tetraconazole in cucumber were in the range of 2.1-3.1 days.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.111-119
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• 2015

BACKGROUND: Ethychlozate (ECZ) is a plant growth regulator of synthetic auxin for agricultural commodities (ACs). Accurate and sensitive method to determine ECZ in diverse ACs on global official purpose is required to legal residue regulation. As the current official method is confined to the limited type of crops with poor validation, this study was conducted to improve and extend the ECZ method using high-performance liquid chromatography (HPLC) in all the registered crops with method verification. METHODS AND RESULTS: ECZ and its acidic metabolite (ECZA) were both extracted from acidified samples with acetone and briefly purified by dichloromethane partition. ECZ was hydrolyzed to form ECZA and the combined ECZA was finally purified by ion-associated partition including hexane-washing. The instrumental quantitation was performed using HPLC/ FLD under ion-suppression of ECZA with no interference by sample co-extractives. The average recoveries of intra- and inter-day experiment ranged from 82.0 to 105.2% and 81.7 to 102.8%, respectively. The repeatability and reproducibility for intra- and inter-day measurements expressed as a relative standard deviation was less than 8.7% and 7.4%, respectively. CONCLUSION: Established analytical method for ECZ residue in ACs was applicable to the nation-wide pesticide residues monitoring program with the acceptable level of sensitivity, repeatability and reproducibility.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.7-17
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• 1972

Samples of 13 vegetables were collected, between 14 July and 6 August, 1971, from 15 markets located in 12 different cities and analyzed for Heptachlor residues by gas liquid chromatograph. The residue concentrations of Heptachlor and its epoxide were estimated separately, at a sensitivity level of 0.001 p.p.m., to produce Heptachlor residues on the fresh weight basis. The Heptachlor residues in or on the crops analyzed, including three staple vegetables, potatoe, radish and chinese cabbage, were found fairly low and are far lower than the residue tolerences for respective vegetables recommended jointly by FAO and WHO of the United Nations.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.306-313
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• 2014

BACKGROUND: Forest soils contain microbes capable of consuming atmospheric methane ($CH_4$), an amount matching the annual increase in $CH_4$ concentration in the atmosphere. However, the effect of plant residue production by different forest structure on $CH_4$ oxidation is not studied in Korea. The objective of this study was to evaluate the effect of Korean alpine soils having different forestation structure on $CH_4$ uptake rates. METHODS AND RESULTS: the $CH_4$ flux was measured at three sites dominated with pine, chestnut and oak trees in southern Korea. The $CH_4$ uptake potentials were evaluated by a closed chamber method for a year. The $CH_4$ uptake rate was the highest in the pine tree soil ($1.05mg/m^2/day$) and then followed by oak ($0.930mg/m^2/day$) and chestnut trees ($0.497mg/m^2/day$). The $CH_4$ uptake rates were highly correlated to soil organic matter and moisture contents, and total microbial and methanotrophs activities. Different with the general concent, there was no any correlation between $CH_4$ oxidation rates, and soil temperature and labile carbon concentrations, irrespective with tree species. CONCLUSION: Conclusively, the methane oxidation rate was correlated in positive manner with organic matter, abundance of methanotrophs. Methane oxidation was different among tree species. This results could be used to estimate methane oxidation rate in forest of Korea after complementing information about statistical data and methane oxidation of other site.