• Journal of Korean Society of Environmental Engineers
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• v.29 no.5
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• pp.540-547
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• 2007

Humic substances(HS) from Han River water was physic-chemically isolated by fractionational methods to investigate the seasonal distribution and to characterize the properties compared with intrinsic humic materials. Various HS samples were analyzed by element, Fourier transform infrared(FT-IR), proton nuclear magnetic resonance$(^1H-NMR)$ and fluorescence analyzers. The portion of HS from Han River water(HRHS) was 47.0% on the average, however it appeared that rainfall event brought about higher fraction of HS in Han River water by the periodic investigation. Aromaticity and humification degree of the HRHS were relatively lower than those of intrinsic humic materials originated from decomposing vegetation. FT-IR, $^1H-NMR$ and fluorescence spectroscopy showed the distinct differences between HRHS and intrinsic humic materials. Commercial humic materials could not represent structural and functional characteristics of local HS. The fluorescence spectroscopy, a relatively simple measurement, was found most useful tool to estimate humification degree for humic materials from particular sources.

• Research in Plant Disease
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• v.18 no.2
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• pp.109-116
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• 2012

A bacterial strain antagonistic to some fungal phytopathogens was isolated from the stem of a Persimmon tree in Yeongam, Korea. This bacterium was identified as Bacillus subtilis by 16S rRNA gene sequencing and designated as B. subtilis GDYA-1. In in vivo experiment, the fermentation broth exhibited antifungal activities against Magnaporthe oryzae on rice plants, Phytophthora infestans on tomato plants, and Puccinia recondita on wheat plants. We isolated one antifungal compound and its chemical structure was determined by mass and $^1H$-NMR spectral data. The antifungal substance was identified as benzoic acid. It inhibited mycelial growth of M. oryzae, Rhizoctonia solani, Sclerotinia sclerotiorum, and P. capsici with minimum inhibition concentration (MIC) values, ranging from 62.5 to 125 ${\mu}g/ml$. Moreover, the substance effectively suppressed Phytophthora blight of red pepper caused by P. capsici in a pot experiment. To the author's knowledge, this is the first report on the antifungal activity of benzoic acid against phytopathogenic fungi. Benzoic acid and B. subtilis GDYA-1 may contribute to environmental-friendly protect crops from phytopathogenic fungi.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.86-92
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• 2019

Polymers with various compositions of azobenzene and hexamethylene groups in the main chain were synthesized by a Schotten-Baumann reaction and their properties were investigated. The chemical structures and physical properties of the synthesized polymers were investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, and x-ray diffraction. The polymers showed an inherent viscosity of 1.28-1.36 dl/g and were relatively insoluble in most organic solvents. The melt transition temperature increased rapidly with increasing number of azobenzene groups in the polymer. When the azobenzene monomer content was more than 50 mol%, no melting transition occurred below the decomposition temperature. Among the polymers with a melt transition temperature, the MP-A3C7 and MP-A5C5 polymers were liquid crystalline materials and exhibited a nematic phase with weak liquid crystallinity over a wide liquid crystal temperature range. This difference in the properties of the synthesized polymers is likely due to the changes in intermolecular forces resulting from the linearity and polarity of the trans-form of azobenzene.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.84-89
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• 2019

To characterize the molecular structure of BzO-gal synthesized using Escherichia coli ${\beta}$-gal, NMR ($^1H$- and $^{13}C$-) spectroscopy and mass spectrometry of BzO-gal were conducted. $^1H$ NMR spectrum of BzO-gal showed multiple peaks corresponding to the galactosyl group, which is an evidence of galactosylation on BzOH. Five proton peaks around the aromatic region at ${\delta}_H$ 7.43 ~ 7.24 ppm and 2 peaks from ${\delta}_H$ 4.93 and 4.67 ppm were evidence of the presence of the benzyl group. Seven proton peaks at ${\delta}_H$ 4.32 ~ 3.46 ppm showed the presence of a monosaccharide and were indicative of galactosylation on BzOH. $^{13}C$ NMR spectrum also revealed the presence of 11 carbons suggestive of BzO-gal. The mass value (sodium adduct ion of BzO-gal, m/z = 293.0994) from mass spectrometry analysis of BzO-gal, and $^1H$ and $^{13}C$ NMR spectral data were in good agreement with the expecting structure of BzO-gal. We are expecting that through future study it will eventually be able to develop a new additive of low cytotoxicity.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.581-587
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• 2022

The leather industry generates a large amount of hazardous leather waste of various types every year. Among them, shaving scrap is difficult to recycle because it contains chromium ions. Many studies in recent years have shown that shaving scraps can be processed into various types of valuable products, such as adsorbent, filler, and poultry feed. In this study, collagen peptides were extracted from shaving scraps and structurally modified to be developed as new materials with improved physicochemical properties. First, the chromium ions contained in the shaving scraps were removed using a sodium hydroxide solution, and purified through concentration and low-temperature crystallization. The purified collagen peptide was used to prepare the powder using a spray dryer. The extracted collagen peptides were structurally modified by introducing double bonds by reacting with methacrylic anhydride (MAA), and the product was confirmed by ¹H NMR spectroscopy. Next, a copolymer was prepared by redox polymerization of the modified collagen peptide (MCP) and 2-ethylhexyl acrylate (2-EHA). The structure of the copolymer was qualitatively confirmed by FT-IR. In conclusion, this study confirmed that collagen peptides can be extracted from shaving scrap and converted into new eco-friendly materials through certain treatments.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.239-253
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• 2021

This study investigates the metabolomic changes in breast and thigh meat from Cobb and Ross 308 chickens regarding the rearing environment. One-day-old Cobb and Ross broilers were raised for 35 days in conventional and animal welfare farms with, amongst others, different floor sizes, stock densities, and ammonia concentrations. One-dimensional ¹H nuclear magnetic resonance, orthogonal partial least squares-discriminant analysis (OPLS-DA), and pathway analyses were performed to analyze the metabolomic properties of broiler meat. For breast meat, only those from the Ross strain could be separated according to the environment in the OPLS-DA plot. Ross breast meat from animal welfare farms showed significantly higher acetate, anserine, creatine, and inosine monophosphate content than those from conventional farms (P<0.05). In contrast, for thigh meat, the Cobb strain was differentiated using OPLS-DA. The contents of five metabolites, such as glucose and lactate, were higher in thigh meat from animal welfare farms; however, nine metabolites, including seven free amino acids, were lower compared to those from conventional farms (P<0.05). Pathway analysis was performed to interpret the biological changes in chicken meat based on environmental factors. The results indicated that the animal welfare environment led to significant changes in four metabolic pathways in Ross breast meat and in 20 metabolic pathways in Cobb thigh meat (P<0.05). In conclusion, the animal welfare environment could influence the metabolomic properties of Ross breast meat and Cobb thigh meat, which may affect the sensory quality of meat.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.26-35
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• 2001

In order to search potent antifungal substances from domestic plants, 40 plants cultivated in Korea were collected. After extracting with methanol (MeOH) and concentrating to dryness, the MeOH extracts were screened for in vivo antifungal activity against six plant diseases at a concentration of $2000{\mu}g/mL$. Fourteen extracts showed disease-controlling activity more than 90% against at least one of the 6 plant diseases tested; eight, seven, and three extracts controlled more than 90% the development of rice blast, tomato late blight, and wheat leaf rust, respectively. However, none of the extracts exhibited in vivo antifungal activity more than 90% against rice sheath blight, tomato gray mold, and barley powdery mildew. From the MeOH extracts of Angelica gigas and A. dahurica showing potent controlling activity against rice blast, 1 and 2 antifungal substances, respectively, were isolated by solvent partitioning and column chromatography. The three compounds were identified to be coumarins, namely, decursin, imperatorin, and isoimperatorin, by mass spectrometry and NMR spectroscopy. They were examined for in vitro and in vivo antifungal activities together with umbelliferone (7-bydroxycournarin) and scopoletin (6-methoxy-7-hydroxycoumarin) containing a free hydroxyl group at position 7 to investigate the structure-activity relationship. In vitro, most of 50% growth inhibitory concentrations ($IC_{50}$) were over $200{\mu}g/mL$, indicating that they have relatively weak antifungal activity. The antifungal activity of decursin and scopoletin, containing cyclic alkoxy groups instead of free hydroxyl group at position 7, was stronger than umbelliferone and scopoletin. Especially, decursin and imperatorin showed potent antifungal activities against Pythium ultimum and Magnaporthe grisea, respectively, with $IC_{50}$ values less than $25{\mu}g/mL$. In vivo, decursin and imperatorin showed potent antifungal activity against rice blast, whereas other coumarins hardly controlled the development of 6 plant diseases tested. These results suggest that the antifungal activity of 7-hydroxycoumarin derivative is substantially increased when the hydroxyl group at position 7 is protected by a stable cyclic alkoxy grouping.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.286-292
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• 2016

1, 2-Hexanediol galactoside (HD-gal) has been synthesized from 1, 2-hexanediol (HD), a cosmetic preservative, using recombinant Escherichia coli ${\beta}$-galactosidase (${\beta}$-gal) at the high lactose concentration (300 g/l). To confirm the molecular structure of synthesized HD-gal, NMR ($^1H$- and $^{13}C$-) spectroscopy and mass spectrometry of HD-gal were conducted. $^1H$ NMR spectrum of HD-gal showed multiple peaks corresponding to the galactocyl group, which is an evidence of galactocylation on HD. Downfield proton peaks at ${\delta}_H$ 4.44 ppm and multiple peaks from ${\delta}_H$3.96~3.58 ppm were indicative of galactocylation on HD. Up field proton peaks at ${\delta}_H$ 1.60~1.35 ppm and 0.92 ppm showed the presence of $CH_2$ and $CH_3$ protons of HD. $^{13}C$ NMR spectrum revealed the presence of 21 carbons suggestive of ${\alpha}$- and ${\beta}$-anomers of HD-gal. Among 12 carbon peaks from each anomers, the 3 peaks at dC 68.6, 60.9 and 13.2 ppm were assigned to be overlapped showing only 21 peaks out of total 24 peaks. The mass value (protonated HD-gal, m/z = 281.1601) from mass spectrometry analysis of HD-gal, and $^1H$ and $^{13}C$ NMR spectral data were in well agreement with the expecting structure of HD-gal. For further study, the minimum inhibitory concentrations (MICs) of HD-gal against bacteria will be investigated, and, in addition, cytotoxicity to human skin cells of HD-gal will be examined. It is expected that it will eventually be able to develop a new cosmetic preservative, which have low cytotoxicity against human skin cell and maintains antimicrobial effect.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.69-74
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• 2001

Purpose: $^{99m}Tc$-HMPAO is a radiopharmaceutical for imaging cerebral blood flow. HMPAO (RR, SS)-4.8-diaza-3,6,6,9-tetramethylundecan-2,10- dione bisoxime) has three stereoismers such as, meso-. d-, and l-HMPAO. Techentium complexes of meso-HMPAO and d,l-HMPAO are known to have different in vivo brain uptakes. In this study, enantiomers of HMPAO (d-HMPAO and l-HMPAO) were separated from d,l-HMPAO. These enantiomers were labeled with $^{99m}Tc$ and the biodistribution studies were performed in mice. Materials and Methods: An intermediate imine product was produced from 2,3-butanedione monooxime and 2,2-dimethyl-1,3-propanediamine (54% yield) and was reduced into a mixture of three isomers (35% yield). The meso-isomer was separated from d,l-mixture by repeated fractional crystallization (11 % yield). The d- and l-enantiomers were subsequently separated by co-crystallization with optical isomers of tartaric acid (25% and 5% yield. respectively). Each enantiomeric HMPAO was labeled with $^{99m}Tc$ by reacting with $SnCI_2{\cdot}2H_2O\;and\;^{99m}Tc$-pertechnetate. Biodistribution study was performed 1 hr after tail vein injection to ICR mice. Results: Radiochemical purities of each compound were over 80%. In biodistribution study. the brain uptakes of d,l- d- and l-form were 1.34, 1.12 and 1.67% ID/g, respectively. In case of l-lsomer the brain uptake was higher (1.5 fold) than d-isomer. Conclusion: We successfully purified each enantiomeric HMPAO. In biodistribution study of stereoismers of $^{99m}Tc$-HMPAO in mice, l-HMPAO may show better brain image than d,l-HMPAO which was supplied in a commercial kit.

• The Korean Journal of Mycology
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• v.32 no.1
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• pp.31-38
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• 2004

An endophytic bacterial strain EB215 that was isolated from cucumber (Cucumis sativus) roots displayed a potent in vivo antifungal activity against Colletotrichum species. The strain was identified as Burkholderia cepacia based on its physiological and biochemical characteristics, and 16S rDNA gene sequence. Optimal medium and incubation period for the production of antifungal substances by B. cepacia EB215 were nutrient broth (NB) and 3 days, respectively. An antifungal substance was isolated from the NB cultures of B. cepacia EB215 strain by centrifugation, n-hexane partitioning, silica gel column chromatography, preparative TLC, and in vitro bioassay. Its chemical structure was determined to be pyrrolnitrin by mass and NMR spectral analyses. Pyrrolnitrin showed potent disease control efficacy of more than 90% against pepper anthracnose (Colletotrichum coccodes), cucumber anthracnose (Colletotrichum orbiculare), rice blast (Magnaporthe grisea) and rice sheath blight (Corticium sasaki) even at a low concentration of $11.1\;{\mu}g/ml$. In addition, it effectively controlled the development of tomato gray mold (Botrytis cinerea) and wheat leaf rust (Puccinia recondita) at concentrations over $33.3\;{\mu}g/ml$. However, it had no antifungal activity against Phytophthora infestans on tomato plants. Further studies on the development of microbial fungicide using B. cepacia EB215 are in progress.