• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.15-25
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• 2023

In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO₂-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm^-1. Such enhancement in ER performance of SiO₂-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.3
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• pp.247-258
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• 2023

This study aims to investigate the enhancement of water resistance and improvement in adhesion to the skin by combining dextrin palmitate and isopropyl titanium triisostearate coating materials with titanium dioxide. Due to the recent increase in consumers who enjoy outdoor activities, the demand for sunscreen with excellent water resistance is increasing. Prior research was conducted with O/W, Pickering, and W/O/W multiple formulations, but there was a limit to water resistance. The purpose of this study is to develop a complex inorganic powder that can improve water resistance and increase adhesion to the skin to solve this problem. First, we combined dextrin palmitate and isopropyl titanium triisostearate coating materials to form a composite with titanium dioxide. The coating of the inorganic powder was confirmed using FE-SEM and FT-IR analysis. The composite exhibited significantly higher in vitro water resistance compared to other formulations. The hydrophobicity of the coated inorganic powder was compared by measuring the contact angles. When the coated inorganic powder was applied to the W/O sunscreen formulation and the non-coated inorganic powder was applied to the W/O sunscreen formulation as a control, the SPF of the sunscreen containing the coated inorganic powder was higher. These results were the same when observed with a UV camera. Finally the adhesion of the coated inorganic powder to the skin was assessed by applying it to a foundation product. In vivo study, it was observed that the product formulated with the coated powder exhibited less smudging compared to the foundation product formulated with the non-coated powder. The developed inorganic powder in this study demonstrated excellent adhesion to the skin, providing a superior sensory experience, as well as enhanced hydrophobicity and remarkable water resistance effects. In the future, the result of this study is expected to help develop various sunscreen products to improve water resistance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.388-397
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• 1985

Forage productivity and sequential changes in forage quality of four rye and two triticale varieties were studied. All the observed characteristics were similar among rye or triticale varieties, but they were different between rye and triticale varieties. Early growth of rye was better compared to triticale varieties, but at heading stage yield in dry weight, digestible dry matter and percent dry matter of triticale were higher compared to rye varieties. Heading stage of rye was earlier than that of triticale by 11 - 14 days. Triticale had longer and broader leaf blades and a higher leaf blade/total dry weight ratio compared to rye. Protein content decreased as plant growth advanced and it was higher in rye before heading, but it was similar after heading compared to triticale. Cellulose and lignin contents of rye increased through 20 days after heading. However, in triticale cellulose increased until heading stage and it levelled off, but lignin content increased rapidly after heading. Among the crude fibers, only acid detergent fibers(ADF) was negatively correlated with in vitro dry matter digestibility(IVDMD) in both rye and triticale. IVDMD of rye decreased rapidly after heading, but it was maintained as high as heading stage up to 15 days after heading in triticale. Protein content and IVDMD in leaf blades were higher than those of culm + leaf sheath, hemicellulose was similar, and cellulose, lignin, and ADF in leaf blades were lower compared to culm + leaf sheath. In the early and middle part of April rye was superior to triticale as a soiling crop because of a better plant growth of rye under the low temperature conditions, but in the later part of April and early part of May triticale was superior to rye because of a rapid decreased in IVDMD of rye after heading and a late maturing characteristics of triticale. Planting both rye and triticale could prolong the utilization period of the soiling crops and increase in yield with better quality compared to a single crop of rye or triticale.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.15-26
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• 2023

Methane production by anaerobic digestion occurs through interspecies electron transfer (DIET), a synthetic metabolism between acetic and methanate bacteria through hydrolysis and acid production steps. In this study, to improve methane yield, the effect of addition of magnetite (Fe₃O₄), a conductor promoting DIET on methane production in food wastewater was investigated, and the effect on methane yield was assessed by methane potential (B_u) and maximum methane production rate [R_m(t₀)] by the operation of batch type anaerobic reactor adding Fe₃O₄. The B_u and R_m(t₀) of food wastewater without Fe₃O₄ were 0.496 Nm³/kg-VSadded and 38.24 mL/day, respectively. The t0 which reached to R_m appeared at 21.06 days during the operation of the anaerobic reactor. The B_u of food wastewater with Fe₃O₄ was 0.502, 0.498, 0.512, 0.510, 0.518, 0.523, 0.524, 0.540, and 0.549 Nm³/kg-VSadded in the treatment of 5, 10, 15, 20, 25, 30, 40, 70, and 100mM-Fe₃O₄, respectively, and the B_u significantly increased to 36.95% with the addition of magnetite in the addition of 15mM-Fe₃O₄. And, the addition of Fe₃O₄ shortened the duration to reach R_m from 21.06 days to the maximum of 14.67 days by the addition of Fe₃O₄. Therefore, the methane yield and production rate of food wastewater significantly improved with the addition of Fe₃O₄.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.35-41
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• 2023

This experiment was carried out to examine double cropping system using Italian ryegrass (IRG) 'Kowinearly', whole crop rice 'Yeongwoo' and barnyard millet 'Jeju native' during the Oct. 2020 to Oct. 2022. Three kinds of forage crops were cultivated at paddy field in Livestock Institute, Jeollanamdo Agricultural Research and Extension Services, Jeollanamdo, South Korea. Whole crop rice (WCR) was sown in late May and barnyard millet (BM) sown early June each year after harvesting IRG. We examined dry matter yield and feed value of forage crops depending on harvest time of forage crops during the experimental period. The plant height in heading stage of IRG ranged from 108 to 112cm and dry matter yield ranged from 6,783 to 11,530 kg ha^-1. The crude protein (CP) of IRG ranged from 6.0 to 8.44%, acid detergent fiber (ADF) ranged from 55.6 to 60.2% and neutral detergent fiber (NDF) ranged from 32.58 to 36.7%, The dry matter yield of WCR increased as the harvest stage was delayed (14,310 kg ha^-1 in milk, 16,167 kg ha^-1 in yellow ripen, and 18,891 kg ha^-1 in mature). Similar to results of dry matter yield of WCR, dry matter yield of BM increased as the harvest stage was delayed (11,194 kg ha^-1 in late heading. and 14,308 kg ha^-1 in mature), However nutrient content of WCR and BM showed a decreasing trend. As shown in above results, the productivity of WCR after harvesting IRG was shown to be high at paddy field in the southern region. However, BM also was appeared to have potential as summer forage crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.26-31
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• 2022

This study was carried out to evaluate the growth characteristics and forage yield potential for warm season grass as emergency forages. The experimental design was a randomized block design (RBD) with three replications. Two barnyard millet (Echinochloa species cv. Shirohie and Jeju native), a pearl millet (Pennisetum glaucum cv Feed milk 2) a proso millet (Panicum miliaceum cv Native), a teffgrass (Eragrostis tef cv. Tiffany) and a kleingrass (Panicum coloratum cv. Selection 75) were compared for forage production and quality at the Mid regions of Korea. Warm season forage crops were sown on May 21 and June 23 respectively, and in 2021, it was sown twice on May 21 and June 21 The number of days to seedling emergence for barnyard millet and teffgrass was observed approximately 10 and 3 days after seeding, respectively. The cultivation period from seeding to harvest was within 60 days for all entry spices except for the late-heading type barnyard millet (within 84 days). As for the dry matter yield by seeding date, the dry matter yield of the late-heading type barnyard millet in May seeding was the highest at 23,872 kg/ha, and the kleingrass was the lowest at 3,888 kg/ha. For the June seeding, the dry matter yield of the late-heading type barnyard millet was 17,032 kg/ha, the highest, and the proso millet, teffgrass and kleingrass showed the lowest at 5,468, 5,442, and 5,197 kg/ha, respectively. The crude protein (CP) content was varied by warm season grass species, but the early-heading type barnyard millet, teffgrass, and kleingrass showed the highest tendency, and the late-heading type barnyard millet showed the lowest at 5.7~5.9%. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) content did not show a significant difference between the seeding in May, but kleingrass in June sowed lower than the others.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.54-60
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• 2022

The planting date of corn for silage has been delayed because of spring drought and double cropping system in Korea. This experiment was conducted to evaluate agronomic characteristics, forage production and feed value of corn at April and May in 2019. Experimental design was a split-plot with three replications. Planting dates (12 April and 10 May) were designated to the main plot, and corn hybrids ('P0928', 'P1543' and 'P2088') to the subplot. The silking days of the early planting date (12 April) was 79 days and that of the late planting date (10 May) was 66 days (p<0.0001), however, there were no significant differences among the corn hybrids. Ear height of the late planting date was higher than that of the early planting (p<0.05), while there were no significant differences in plant height of corn. Insect resistance at the early planting was lower than that of late planting (p<0.05), however, lodging resistance was no significant difference at planting date. The rice black streaked virus (RBSDV) infection of early planting was 3.7% and that of late planting was 0.3% (p<0.001). Dry matter (DM) contents of stover, ear and whole plant had significant difference at planting date (p<0.05). And differences in ear percentages were observed among the corn hybrids (p<0.01). And ear percentages of early maturing corn ('P0928') was higher than for other hybrids. Ear percentage at the early planting date was higher than that at the late planting date (p<0.01). DM and total digestible nutrients (TDN) yields had significant difference at planting date, however, there were no significant differences among the corn hybrids. DM and TDN yields at the late planting (21,678 kg/ha and 14,878 kg/ha) were higher than those of the early planting (13,732 kg/ha and 9,830 kg/ha). Crude protein content at the early planting date was higher than that of the late planting. Acid detergent fiber content of the late planting was lower than that of the early planting date (p<0.01), while there were no significant neutral detergent fiber content difference among the corn tested. Calculated net energy for lactation (NE_L) and TDN at the early planting were higher than those of at the late planting (p<0.01). Results of this our study indicate that the late planting date (May) is better than early planting date (April) in forage yield and feed value of corn. Therefore, the delay of planting date by May was more suitable for use in cropping system.

• Journal of Life Science
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• v.32 no.3
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• pp.202-209
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• 2022

The green alga Chlamydomonas reinhardtii, a unicellular haploid eukaryote, has long been used by researchers and industries as a cell factory to produce high value-added microalgae substances using genetic modification. Microalga K01, presumed to be Chlamydomonas, was isolated from 12 freshwater samples from the Chungcheong and Jeolla regions to replace C. reinhardtii, an introduced species currently used in most basic and industrial research. The isolated K01 strain was identified as C. reinhardtii through morphological and phylogenetic studies of the 18S rDNA gene sequence (NCBI accession number KC166137). The growth and lipid content of the isolated C. reinhardtii K01 were compared with three wild and four mutant strains in TAP medium, and it was found that the K01 strain could produce 1.74×10⁷ cells/ml by the third day of culture. The growth rate of C. reinhardtii K01 was 1.5 times faster than UTEX2244, which showed the highest number of cells (1.20×10⁷ cells/ml) among the compared strains. The lipid content of the isolated C. reinhardtii K01 (20.67%) was similar to those of the wild strains, although the fatty acid oleate C18:1 was not detected in the isolated strain but was identified in the seven others. The cell density of the isolated strain increased to 0.87 g/l during a six-day culture in BG11 medium, where nitrate (NaNO₃) was introduced as a nitrogen source, while the seven acquired strains showed almost no cell proliferation.

• Clean Technology
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• v.29 no.2
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• pp.126-134
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• 2023

Direct catalytic decomposition is a promising method for controlling the emission of nitrous oxide (N₂O) from the semiconductor and display industries. In this study, a γ-Al₂O₃ catalyst was developed to reduce N₂O emissions by a catalytic decomposition reaction. The γ-Al₂O₃ catalyst was prepared by an extrusion method using boehmite powder, and a N₂O decomposition test was performed using a catalyst reactor that was approximately 25.4 mm (1 in) in diameter packed with approximately 5 mm of catalysts. The N₂O decomposition tests were carried out with approximately 1% N₂O at 550 to 750 ℃, an ambient pressure, and a GHSV=1800-2000 h^-1. To confirm the N₂O decomposition properties and the effect of O₂ and steam on the N₂O decomposition, nitrogen, air, and air and steam were used as atmospheric gases. The catalytic decomposition tests showed that the 1% N₂O had almost completely disappeared at 700 ℃ in an N₂ atmosphere. However, air and steam decreased the conversion rate drastically. The long term stability test carried out under an N₂ atmosphere at 700 ℃ for 350 h showed that the N₂O conversion rate remained very stable, confirming no catalytic activity changes. From the results of the N₂O decomposition tests and long-term stability test, it is expected that the prepared γ-Al₂O₃ catalyst can be used to reduce N₂O emissions from several industries including the semiconductor, display, and nitric acid manufacturing industry.

• Journal of Life Science
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• v.33 no.6
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• pp.471-480
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• 2023

This study was designed to evaluate the anti-inflammatory effects of Rumohra adiantiformis extracts fermented with Bovista plumbea mycelium (B-RAE) in LPS-stimulated RAW 264.7 cells. The total polyphenol and total flavonoid content of B-RAE were 379.26±7.77 mg/g and 50.85±3.08 mg/g, respectively. The results of measuring the antioxidant activity of B-RAE showed that it scavenges 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and superoxide anion radical in a dose-dependent manner. B-RAE inhibited nitric oxide (NO) production in a dose-dependent manner without affecting cell viability. The gene expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-lβ (IL-1β), and IL-6 was measured using real time quantitative reverse transcription PCR (qRT-PCR). We found that, compared to the LPS-treated group, B-RAE significantly reduced the mRNA levels of the pro-inflammatory cytokines in a concentration-dependent manner. The expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), the phosphorylation of transcription factors such as nuclear factor-κB (NF-κB), and the mitogen-activated protein kinase (MAPK) signaling pathway proteins were assessed using Western blot analysis. We found that B-RAE significantly suppressed the expression of iNOS and COX-2, but their expression was increased by LPS treatment. In addition, the phosphorylation of NF-κB and IκB, which was increased by LPS treatment, was reduced with B-RAE treatment. The effect of B-RAE on the phosphorylation of the MAPK signaling pathway proteins was measured, and the phosphorylation of extracellular signal-regulated kinase (ERK) and the p38 MAPK proteins decreased in a dose-dependent manner, while the phosphorylation of c-Jun N-terminal kinase (JNK) increased. These anti-inflammatory effects of B-RAE may thus have been achieved through the high antioxidant activity, the inhibition of NO production through the suppression of iNOS and COX-2 expression, the inhibition of the NF-κB pathway, and the suppression of pro-inflammatory cytokine expression.