• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.125-131
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• 2024

In this study, synthesized Ni/Ce_xZr_1-xO₂ catalysts were coated on the surface of honeycomb metalic monoliths to investigate catalytic activity in steam reforming of methane reactions. Supports with varying Ce/Zr ratios were synthesized to observe their behavior in the reforming reaction, and catalysts with Ni contents ranging from 5 wt% to 20 wt% were prepared to analyze the effect of Ni loading contents on catalytic activity. The catalysts were characterized by XRD, BET, TPR, and SEM. The TPR analysis indicated the formation of Ni-Ce-Zr oxide with a strong interaction between the active metal Ni and CeO₂-ZrO₂ support. The 15 wt% Ni/Ce_0.80Zr_0.20O₂ catalyst exhibited the highest activity and stability in the steam reforming of methane reaction. Catalysts with enhanced activity and stability were synthesized by manufacturing composite materials using excellent oxygen storage and donor properties of CeO₂ and the thermal properties of ZrO₂.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.8-19
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• 1989

The proportion of imported wood has been now over 80% of raw materials needed in the wood industry, and therefore, many of studies on the substitution of domestic wood for imported wood and on the increasing the utilization rate of domestic species have been attempted and considered as very important projects to solve. But these trials were practically restricted by several disadvantages of domestic species. such as a small diameter, variety of species, and irregularity of wood physical or chemical characteristics, etc. From a this point of view, this study was carried out to investigate solid wood bending properties of sample trees and then to develop their end uses. The species of sample trees were Pinus densiflora S. et Z., Pinus rigida Mill., and Larix leptolepis Gord. which have large growing stocks but Pinus rigida and Larix leptolepis have not been used well because of their poor qualities. The results obtained were as follows: 1. The optimum conditions for solid wood bending processing of Pinus densiflora, Pinus rigida, and Larix leptolepis are showed in Table 6. 2. The minimum solid-bending radii of Pinus densifjora, Pinus rigida, and Larix ieptolepls were 260mm, 240mm, and 300mm, respectively in steaming treatment.

• Proceedings of the Korean Sanitation Conference
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• 2005.12a
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• pp.76-97
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• 2005

As the recent change of multiformity and taste in clination in eating habit culture is yearly in creasing foods used oil and fats. Because the frying food is especially important snack , it's safty is very essential. In order to know the safty and harmfulness of frying oil and fats. The 20 kinds samples were purchased chicken fried food shops around the north of seoul and kyunggi. The acid value, iodine value, peroxide value, TBA value, fatty acid, carbonyl value, and smoke point of deep fat fried oils were analyzed. Results of analyzed, A company of deep fat frying oil showed stability state and C company and B company of deep fat frying oil is acidification to turned. But D company of deep fat frying oil showed quite a bit acidification progressived of used hydrogenated oil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1139-1145
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• 2006

In this study, antioxidant activities of enzymatic and methanolic extracts from E. cava stem and leave were evaluated by measuring the scavenging activities on 1,1 diphenyl 2 picrylhydrazyl (DPPH), hydroxyl radical, hydrogen peroxide and the inhibitory effects on DNA damage induced by oxidative stress of cells. Enzymatic extracts were prepared by enzymatic hydrolysis of both stem and leave using food grade five different carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase). The enzymatic extracts were lower than methanolic extracts in polyphenol contents, but higher in extraction yield by approximately 30%. The enzymatic extracts were superior to methanolic extracts in DPPH and H2O2 scavenging activities and DNA damage protective effect. There were no significant antioxidant activity difference between stem and leave, but the extracts of leave were relatively better than those of stem. In this study it is suggested that E. cava stem as well as its leave would be a good raw materials for antioxidants compound extraction and enzymatic hydrolysis would be a good strategy to prepare antioxidant extracts from seaweeds.

• Journal of the Korean Applied Science and Technology
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• v.40 no.3
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• pp.534-546
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• 2023

In this study, we investigated the antioxidant and anti-winkle activity in human fibroblast cell (CCD-986sk) of Persimmon Leaves (PL) as a cosmetic ingredient. As a result of investigating antioxidant activity through electron-donating ability and ABTS⁺ radical scavenging assay, the PL showed concentration-dependent antioxidant activity similar to ascorbic acid, a control group, at a concentration of 1,000 ㎍/ml. As a result of investigating the anti-wrinkle effect through elastase inhibition and collagenase inhibition assay, the PL showed concentration-dependent antioxidant activity similar to epigallocatechin gallate, a control group, at a concentration of 1,000 ㎍/ml. As a result of measuring the synthesis rate of pro-collagen type I and the inhibition rate of MMP-1 in UVB-induced CCD-986sk cells, the control group EGCG showed a 90.2% pro-collagen synthesis rate at 20 ㎍/ml and PL showed an 88.5% synthesis rate at 30 ㎍/ml. In addition, the inhibition rate of MMP-1 of 33.0% and 40.8% were confirmed in EGCG 20 ㎍/ml and PL 30 ㎍/ml, respectively. As a result of measuring the protein expression of pro-collagen type I and MMP-1 in the PL through western blot, it was confirmed that the protein expression of pro-collagen type I increased, and MMP-1 decreased when the PL was treated together compared to the UVB alone group. According to the above experimental results, it is expected to be used as a natural product material for cosmetics by confirming that the PL prevent photoaging caused by UVB stimulation and have antioxidant and anti-wrinkle effects.

• Journal of The Korean Association For Science Education
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• v.39 no.6
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• pp.717-728
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• 2019

The cultivation of creative convergence talent has become more important than ever, the Korean curriculum has also undergone many changes, aiming for convergence and integrated education. In addition to these changes in science and curriculum, we examined the changes in perception and Professionalism(PCK) of integrated science education of science teachers over the past decade. For this study, 359 elementary and secondary science teachers in 2008, when the 2007 revised curriculum was applied, and 360 elementary and secondary science teachers in 2018, when the 2015 revised curriculum was applied, were examined for 10 years of changes in perceptions and PCK of integrated science education. The conclusions from the analysis were as follows. First, in 2018, elementary and secondary science teachers were found to have a statistically significant increase in awareness of integrated science education. Nevertheless, cognition was found to be 'normal'. Second, teachers' perception of the necessity of improving the professionalism of teachers, providing teaching and learning materials, reducing the contents of learning, reducing the number of students and securing flexible timetables, and raising the perception of integrated science education for students and parents as a condition for the success of integrated science education, was analyzed to be significantly higher in 2018. Third, the results of PCK survey through self-diagnosis, teachers' PCK on integrated science education, such as competence to secure curriculum contents knowledge, comprehension of curriculum and class composition related to integrated science education, teaching strategy for integrated, creation of teaching and learning environment for integrated teaching, efforts to improve administrative constraints and the professionalism of integrated science education, was significantly higher than it was ten years ago. Therefore, the recent emphasis on convergence education has increased the experience of applying convergence classes in the field of education, and it was seen as a result of the continuous efforts of science teachers to meet the changes in the education paradigm.

• Journal of Life Science
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• v.26 no.10
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• pp.1207-1213
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• 2016

Schisandrae fructus (SF) and Mori folium (MF) have been used as traditional medicines for thousands of years in parts of Asia, including Korea, China, and Japan. Recent researches on SF and MF have documented a wide spectrum of therapeutic properties, including anti-microbial, anti-inflammatory, anti-oxidative, immunomodulatory and anti-angiogenesis effects. However, the toxicity and safety of SF and MF, and their mixture (medicinal herber mixture, MHMIX) were not confirmed. Therefore, this study was performed to evaluate the acute toxicity and safety of SF, MF and MHMIX. SF, MF and MHMIX were orally administered at a dose of 5,000 mg/kg in ICR mice. Animals were monitored for the mortality and changes in the body weight, clinical signs and gross observation during the 14 days after dosing, upon necropsy. We also measured parameters of organ weight, clinical chemistry, and hematology. No dead and no clinical signs were found during the experiment period after administration of a single oral dose of SF, MF and MHMIX. There were no adverse effects on clinical signs, body weight, or organ weight and no gross pathological findings in any treatment group. Therefore, LD50 value of SF, MF and MHMIX may be over 5,000 mg/kg and it may have no side toxic effect to ICR mice. The results on the single-dose toxicity of SF, MF and MHMIX indicate that it is not possible to reach oral dose levels related to death or dose levels with any harmful side effects.

• Journal of Chitin and Chitosan
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• v.23 no.4
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• pp.244-255
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• 2018

Natural extract in liquid phase was adjusted to 0, 0.25, 0.5, 1, 2, and 4% concentration to check microbial changes and to measure 4, 8, $12^{\circ}C$ for refrigeration temperature. In the case of grapefruit extract, the microbial safety was maintained at all the concentrations at $4^{\circ}C$ storage, but the antimicrobial activity was maintained at $12^{\circ}C$ storage and at $8^{\circ}C$ and 21 days storage. In the case of grape seed extract, only the 4% of the culture at $8^{\circ}C$ satisfied the requirement of safety of food distribution for the last 21 days, and the safety criterion was satisfied only at 4% concentration at $12^{\circ}C$ for 18 days. Complex Scutellaria baicalensis extract showed the total number of microbial cells treated by concentration. It was confirmed that microbial flow safety was maintained at low temperature ($4^{\circ}C$). However, at $8^{\circ}C$ and $12^{\circ}C$, Exceeded the distribution limit. When polylysine was applied to brown rice cake, it showed activity in all groups except $4^{\circ}C$, but these properties were not observed at $8^{\circ}C$ and $12^{\circ}C$. At a concentration of 0.5% or more of chitosan, the growth of the microorganism is suppressed by the 21st day very stably, and a similar tendency is observed at 8 and $12^{\circ}C$, so that it may be an antimicrobial material that inhibits microorganisms. At the first day, the distribution standards for general bacterial counts were exceeded.Ethyl-pyruvate showed that microorganism safety was maintained at $4^{\circ}C$ and 1% concentration, and food safety was stable even at 2 or 4%. Glycine showed very good and stable distribution stability at $4^{\circ}C$. However, at $8^{\circ}C$ and $12^{\circ}C$, the shelf life of 14 days could not be maintained as with the addition of other antimicrobial active substances.

• Journal of dental hygiene science
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• v.18 no.6
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• pp.327-339
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• 2018

This study aimed to provide basic data for establishing the clinical basis for dental hygienist-led dental hygiene process of care by identifying multiple risk factors for self-support program participants in Gangneung city; we also compared oral health status and behavioral changes through customized oral health care. Four dental hygienists who were evaluated for degree of conformity provided dental hygiene process of care to eight self-support program participants who were selected as having an oral health risk among people in the self-support center. The clinical indicators measured during dental hygiene assessment and evaluation and behavioral changes due to dental hygiene intervention were compared and analyzed. With respect to clinical indicators, at the time of probe, the retention rate of patients with gingival bleeding decreased from 61.4% to 14.7% after intervention (p=0.004). Furthermore, the retention rate of patients with a periodontal pocket >4 mm decreased from 15.6% to 5.8% (p=0.001). The average modified O'Leary index of the patients improved from 23 to 40 (p=0.002). Previously, all eight subjects used the vertical or horizontal method of brushing; after dental hygiene care interventions regarding method and frequency of toothbrushing, use of oral care products, and individual interventions, they started using the rolling or Bass method of toothbrushing. Four of eight subjects reported using interdental toothbrushes after intervention. As a result of applying the change model to the transtheoretical behavior change of the subject, the result of strengthening the health behavior was confirmed. For promotion of oral health by the prevention-centered incremental oral health care system, dental hygienist-led dental hygiene management and maintenance is essential. It is thought that continuous research, such as for feasibility evaluation, cost benefit analysis, and preparation of legal systems, is needed to establish and activate dental hygiene management.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.582-591
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• 2022

This study was conducted to eliminate Myocastor coypusMolina, 1782 (Nutria) from Jeju Special Self-Governing Province, South Korea. Habitat identification and eradication were carried out from September to November 2013, and a survey was carried out until June 2022 to check whether the eradication was successful. The habitat was identified with unmanned cameras, interviews, and literature surveys, and the capture was performed using the trapping method with food to attract nutria to the habitat area. The study area for the follow-up survey, which was set relatively wide considering nutria's home range, included wetlands and rivers within 4.0 km² of the habitat area (eradication area). As a result, nutria's habitat was confirmed only at Songdang Ranch, Songdang-ri, of Jeju Island, with traces of habitat (footprints, excrement, and burrows) confirmed in waterways and ponds within the pasture. Eight individuals were captured, including four females, three males, and one individual in too advanced a state of decay to identify the sex. The follow-up survey thoroughly investigated the habitat and its surroundings, focusing on three areas with permanent water, Seongeup Reservoir, Cheonmi Creek, and Molsuni Pond, but no signs of habitat were identified. Therefore, it is determined that nutria inhabiting Jeju Island has been completely eradicated. It is believed that the successful eradication of nutria in the Jeju Special Autonomous Region was possible due to a synergy between 1) the eradication of nutria at the beginning of the settlement phase through rapid capture after confirming the nutria habitat and 2) the delayed expansion period because of rare presence of wetlands, where water is constantly stagnant, on Jeju Island. These results imply that quickly identifying the ecological characteristics of the species and preventing disturbances before they or at the beginning of the ecological disturbance through control and eradication at the initial stage of settlement before the expansion stage is an effective measure to cope with the influx of alien species.