• Journal of Sericultural and Entomological Science
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• v.40 no.1
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• pp.63-69
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• 1998

Twenty seven out of ca. 5,000 actinomycete strains, which were isolated from soil collected throughout the country, showed antibicrobial effects against fungai, Rhizopus stronifer (ATCC 6227a), Rhizoctonia solani (KCCM 11271) and yeast, Candida albicans (ATCC 10231). From these antifungal microorganisms, we further selected seven strains which seemed to produce insecticidal substances with in vivo test, using silkworm, Bombyx mori and beet armyworm, Spodoptera exigua. Morphological and biochemical experiments revealed that three strains out of seven were Streptomyces. Further investigations on the physical and chemical properties of these antifungal and insecticidal substances are now in progress.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.296-304
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• 1994

Antibiotic substances were produced by Bacillus subtilis YB-70, a potential biocontrol agent found to suppress root-rot of eggplant (Solanum melonggena L) caused by Fusarium solani, in a dextrose glutamate medium and isolated by isoelectric precipitation. Partial purification was performed by column chromatography on silica gel with two solvent systems: chloroform-methanol and methanol-chloroform-water as eluting solvents, This active fraction YBS-1 s contained antifungal activity were soluble in ethanol, methanol, and water, but were not soluble in other solvents including acetone, butanol, ethyl ether, dimethylformamide, propanol, and etc. High performance liquid chromatography and thin layer chromatographic separation of YBS-1s showed that they have been composed of three biological active bands that were named YBS-1A, -1B, and -1C. The substances were stable to heat and resistant to protease. YBS-1s were active against a wide range of plant pathogenic fungi but did not inhibit the growth of bacteria and yeasts. They were not only fungicidal but also fungistatic against chlamydospores of F. solani. The $ED_{50}$ values for the chlamydospore germination and the germ-tube growth of F. solani were $O.725\mu\textrm{m}/ml\;and\;O.562\mu\textrm{m}/ml$, respectively. Microscopic observations proved the substances restricted the growth of phytopathogenic fungus F. solani by spore burst followed by dissolving of its germ-tube, and caused abnormal hyphal swelling after application to chlamydospores or growing hyphae. Cultural filtrate of B; subtilis YB-70 also suppressed the development of root-rot of eggplant in pot tests.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.58-71
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• 2015

Objectives: The aims of this study were to investigate the classification system of chemical substances in the Occupational Safety and Health Act(OSHA) and Chemical Substances Control Act(CSCA) and to compare several health indices (i.e., Time Weighted Average (TWA), Lethal Dose ($LD_{50}$), and Lethal Concentration ($LC_{50}$) of chemical substances by categories in each law. Methods: The chemicals regulated by each law were classified by the specific categories provided in the respective law; seven categories for OSHA (chemicals with OELs, chemicals prohibited from manufacturing, etc., chemicals requiring approval, chemicals kept below permissible limits, chemicals requiring workplace monitoring, chemicals requiring special management, and chemicals requiring special heath diagnosis) and five categories from the CSCA(poisonous substances, permitted substances, restricted substances, prohibited substances, and substances requiring preparation for accidents). Information on physicochemical properties, health indices including CMR characteristics, $LD_{50}$ and $LD_{50}$ were searched from the homepages of the Korean Occupational and Safety Agency and the National Institute of Environmental Research, etc. Statistical analysis was conducted for comparison between TWA and health index for each category. Results: The number of chemicals based on CAS numbers was different from the numbers of series of chemicals listed in each law because of repeat listings due to different names (e.g., glycol monoethylether vs. 2-ethoxy ethanol) and grouping of different chemicals under the same serial number(i.e., five different benzidine-related chemicals were categorized under one serial number(06-4-13) as prohibited substances under the CSCA). A total of 722 chemicals and 995 chemicals were listed at the OSHA and its sub-regulations and CSCA and its sub-regulations, respectively. Among these, 36.8% based on OSHA chemicals and 26.7% based on CSCA chemicals were regulated simultaneously through both laws. The correlation coefficients between TWA and $LC_{50}$ and between TWA and $LD_{50}$, were 0.641 and 0.506, respectively. The geometric mean values of TWA calculated by each category in both laws have no tendency according to category. The patterns of cumulative graph for TWA, $LD_{50}$, $LC_{50}$ were similar to the chemicals regulated by OHSA and CCSA, but their median values were lower for CCSA regulated chemicals than OSHA regulated chemicals. The GM of carcinogenic chemicals under the OSHA was significantly lower than non-CMR chemicals($2.21mg/m^3$ vs $5.69mg/m^3$, p=0.006), while there was no significant difference in CSCA chemicals($0.85mg/m^3$ vs $1.04mg/m^3$, p=0.448). $LC_{50}$ showed no significant difference between carcinogens, mutagens, reproductive toxic chemicals and non-CMR chemicals in both laws' regulated chemicals, while there was a difference between carcinogens and non-CMR chemicals in $LD_{50}$ of the CSCA. Conclusions: This study found that there was no specific tendency or significant difference in health indicessuch TWA, $LD_{50}$ and $LC_{50}$ in subcategories of chemicals as classified by the Ministry of Labor and Employment and the Ministry of Environment. Considering the background and the purpose of each law, collaboration for harmonization in chemical categorizing and regulation is necessary.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.67-78
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• 2024

Light absorption has potential as a signal in biochemical analyses due to its simplicity in measurement and interpretational clarity. Among substances that generate absorption signals, gold nanoparticles possess advantages such as chemical stability, biological compatibility, and unique optical properties from the localized surface plasmon resonance (LSPR) in the visible light range. They also exhibit versatility compared to other colorimetric substances effective only for specific target molecules, as they easily conjugate with various detection active substances like antibodies and aptamers. Particularly due to advantages such as low cost, ease of particle synthesis, and high environmental stability compared to enzyme-based colorimetric methods, gold nanoparticles are extensively researched as signal substances in colorimetric assays. This review summarizes various strategies utilizing gold nanoparticles as absorption signal substances, focusing on recent research. Based on the characteristics of gold nanoparticles, where the optical property is influenced by particle morphology, literature is classified and reviewed based on strategies controlling the shape of gold nanoparticles during signal generation. Through this, it is observed that gold nanoparticles, which have been used as absorption signal substances, continue to be actively researched, affirming their potential for broad and continuous improvement in the future.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.15-21
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• 2006

Composite materials were prepared by impregnating water glass into the wood, followed by soaking in solutions of boric acid or phosphoric acid. The effects of these treatments on the physical and mechanical properties of the specimens and especially on its heat resistance were investigated. 1) Weight Percent Gain (WPG)s increased with increase of concentrations of water glass. However, there was little relationship between treatment temperatures and WPG. Generally, WPGs of double treated specimens were higher than single treated ones. 2) Percent shrinkages in each directions of the specimens treated with water glass had higher value than other specimens. Percent shrinkages of the specimens treated with boric acid or phosphoric acid were decreased as compared with untreated specimen. However, the specimens treated with water glass or phosphoric acid showed very high hygroscopicity. 3) The bending strengths of all specimens treated inorganic substances were slightly decreased. However, the values of compressive strength and hardness of most specimens treated with inorganic substances increased or similar to that of untreated specimen except for a phosphoric acid treated specimens. 4) The specimens had good heat resistance. Weight losses of all specimens treated inorganic substances were about 50~70%. In particular, the specimens treated at $300^{\circ}C$ and $400^{\circ}C$ almost kept their shapes.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.330-339
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• 2024

Corn cobs were fermented with Aspergillus niger to produce soluble dietary fiber (SDF) of high quality and excellent food safety. In this work, the fermentation process was optimized by single-factor test and response surface methodology (RSM). The optimal fermentation conditions were determined to be a material-liquid ratio of 1:30, an inoculum concentration of 11%, a temperature of 32℃, a time of 6 days, and a shaking speed of 200 r/min. Under these conditions, the SDF yield of corn cob increased from 2.34% to 11.92%, and the ratio of soluble dietary fiber to total dietary fiber (SDF/TDF) reached 19.08%, meeting the requirements for high-quality dietary fiber (SDF/TDF of more than 10%). Scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FT-IR) analysis revealed that the fermentation effectively degraded part of cellulose and hemicellulose, resulting in the formation of a loose and porous structure. After fermentation the water swelling capacity, water-holding capacity, and oil-holding capacity of the corn cob SDF were significantly improved and the adsorption capacity of glucose, cholesterol, and nitrite ions all increased by more than 20%. Moreover, the total phenolic content increased by 20.96%, which correlated with the higher antioxidant activity of SDF. Overall, the fermentation of corn cobs by A. niger increased the yield and enhanced the functional properties of dietary fiber (DF) as well.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.111-116
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• 2006

The microstickes control effects of some fixing agents, including an inorganic PAC, an organic polyamine (PA) and polydiallydimethyl ammonium chloride (Pdadmac), and a high cationic starch (HCS), were investigated, together with their effects on wet end performances and physical properties of handsheets. Despite that the HCS and Pdadmac had lower cationic charge densities than the PA and PAC (the HCS being even lower), they gave higher zeta potentials to fibers, and lower turbidities, cationic demands and residual COD contents to the pulp liquid phases than the PA and PAC did. In all cases, the HCS showed even better effects than the Pdadmac. In addition, drainage speed was also much higher by the HCS treatments although paper formation was worsened. All the phenomena showed that the HCS can fix more dissolved and colloidal substances to cellulose fibers, indicating that the HCS functioned mainly with flocculation and even hydrogen bonding mechanisms. Data on optical properties further indicated that the HCS interacted preferentially with colloidal substances, since it fixed more 'dirty' microstickes to fibers which decreased more sheet brightness while increasing more sheet opacity (with both higher light absorption and scattering coefficients). Interestingly, the organic fixing agents did not decrease tensile, tearing, and folding strengths of paper sheets made from 100% recycled newsprint pulp, except when they were dosed in high amounts. On the contrary, the inorganic PAC had more serious negative effects on the strength properties, especially on folding endurance. The study suggested that proper use of the HCS can lead to better microstickies control effects than traditional agents and methods.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.353-373
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• 2023

Kimchi is a traditional Korean dish made with salted fermented vegetables and contains various nutrients and functional substances with potential health benefits. The fermentation process used to make kimchi creates chemical changes in the food, developing nutrients and functional substances that are more easily absorbed and enhanced by the body. Recent studies have shown that several lactic acid bacteria strains isolated from kimchi exhibit probiotic properties and have several health benefiting properties such as such as anticancer, anti-obesity, and anti-constipation; they also promote colon health and cholesterol reduction in in vitro and in vivo experiments, as well as in epidemiological cohort studies. Kimchi contains prebiotics, non-digestible fibers that nourish beneficial gut bacteria; therefore, its intake effectively provides both probiotics and prebiotics for improved gut health and a fortified gut-derived immune system. Furthermore, fermentation of kimchi produces a variety of metabolites that enhance its functionality. These metabolites include organic acids, enzymes, vitamins, bioactive compounds, bacteriocins, exopolysaccharides, and γ-aminobutyric acid. These diverse health-promoting metabolites are not readily obtainable from single food sources, positioning kimchi as a valuable dietary option for acquiring these essential components. In this review, the health functionalities of kimchi ingredients, lactic acid bacteria strains, and health-promoting metabolites from kimchi are discussed for their properties and roles in kimchi fermentation. In conclusion, consuming kimchi can be beneficial for health. We highlight the benefits of kimchi consumption and establish a rationale for including kimchi in a balanced, healthy diet.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.87-94
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• 2021

While the shielding substances of radiation shields in medical institutions are beginning to be replaced by environmentally friendly materials, radiation protection according to the shielding properties of environmentally friendly substances is becoming an important factor rather than the existing lead shielding properties. Tungsten and barium sulfate are representative shielding materials similar to lead, and are made in sheets or fiber form with eco-friendly materials. Ytterbium is an impermeable material used as a fluorine compound in the dental radiation field. This study aims to evaluate the shielding performance in the x-ray shielding area by comparing the shielding properties of ytterbium by energy band and that of existing eco-friendly materials. When three types of shielding sheets were fabricated and tested under the same process conditions, the shielding performance of the medical radiation area was about 5 % difference from tungsten. Furthermore, shielding performance was superior to barium sulfate. In the cross-sectional structure of the shielding sheet, there was a disadvantage that the arrangement of particles was not uniform. Ytterbium oxide showed sufficient potential as a medical radiation shielding material, and it is thought that it can improve the shielding performance by controlling the particle arrangement structure and particle size.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.2
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• pp.31-37
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• 1999

To enhance antibiotic function of plastic containers, many methods have been applied. Most of the methods utilize antibiotic properties of antibiotic substances such as silver containing chemicals. Sometimes antibiotic substances are used without long term stability test as food container additives. Basically, this kind of methods is not safe since it is based on the antibiotic properties of the material itself and hence direct contact between food and container additives is unavoidable to obtain antibiotic effect. In this paper, a new concept of information templation was applied to make food containers with antibiotic function. It has been known recently that water memorize informations and this information could be tempelated to other materials through appropriate methods. One of the participating company developed this method to template informations onto plastic materials. Food containers were produced using this plastic chips and experimental results showed that antibiotic functional information temptation method is effective for practical application. Results and discussions are reported in this paper.