• 한국식품과학회지
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• 제32권1호
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• pp.168-173
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• 2000

애사과 polyphenol의 충치예방효과를 확인하고자, S. mutans 4 균주 가운데 GTase 활성이 가장 높은 S. mutans MT 8148 균주에 대하여 애사과 polyphenol의 GTase 활성억제효과, cell adherence 억제효과, 산 생성억제효과를 측정하였다. S. mutans GTase에 대한 활성 억제효과는 애사과 polyphenol 성분 중 (+)-catechin과 tannic acid가 1 mg/ml의 농도에서 60% 이상, 5mg/ml의 농도에서 90% 이상으로 높게 나타났다. S. mutans의 adherence에 대해서는 tannic acid가 약 50% 정도의 억제효과를 나타냈으며, 애사과 추출물도 약 30%정도의 억제효과를 보였다. 그러나 S. mutans의 산 생성에 대해서는 애사과 polyphenol 성분들이 억제효과를 나타내지 못하는 것으로 나타났다. 애사과 polyphenol 성분들의 S. mutans에 대한 항균활성을 확인한 결과, 이들은 항균활성은 갖지 않는 것으로 나타났다. 애사과 polyphenol의 충치억제효과는 주성분중의 하나인 catechin과 tannic acid의 S. mutans GTase 활성억제와 cell adherence 억제효과로부터 기인된 것임을 알 수 있었다. 따라서 애사과 추출물은 충치예방을 위한 기능성 식품소재로 사용 가능할 것으로 생각된다.

• 한국토양비료학회지
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• 제34권2호
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• pp.110-116
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• 2001

벼 2모작 재배시 보릿짚시용후 질소시용량별 토양의 이화학적 변화와 수도체의 양분흡수량, 질소이용효율을 조사하기 위하여 2년간('97~'98) 전북통에서 시험한 결과는 다음과 같다. 보릿짚시용으로 경도, 용적밀도, 고상율이 낮아졌고 공극율과 기상율이 증가하여 토양의 물리성이 개선되었다. 보릿짚시용으로 벼 재배후 토양의 pH, OM, T-C, $SiO_2$, K, CEC가 증가한 반면 $P_2O_5$이 감소되었다. 보릿짚시용후 벼 재배시 토양중 $Fe^{+{+}}$함량은 분얼기~유수형성기까지 높은 함량을 보였으나 출수기에는 낮아졌고 $Mn^{+{+}}$함량은 증가되었다. 보릿짚시용시 수도체로의 시비질소 흡수량은 질소시용량 $126kg\;ha^{-1}$ 시용구까지는 증가하였으나 질소 $144kg\;ha^{-1}$ 시용구에서는 감소되었다. 또 질소시용량이 적을수록 보릿짚시용구에서 무시용구보다 시비질소 흡수기간이 길었다. 수도체로의 질소이용율은 분얼기에는 1% 전후였지만 최고분얼기부터 크게 증가하였고 보릿짚시용구에서 낮았다. 수도체로의 인산흡수량은 보릿짚시용구에서 질소시용량에 관계없이 모두 높았으나 칼리함량은 낮았다.

• 약학회지
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• 제58권5호
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• pp.307-313
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• 2014

Rumex crispus (curled dock), which is a perennial wild plant, has long been used as a laxative, astringent, and medicine to treat blood and skin diseases. We recently reported that the roots of R. crispus are an effective nutraceutical for bone. This study prepared ethanol extracts of the leaves and roots of R. crispus, and analyzed the major constituents using liquid chromatography and mass spectrometry. In addition, their effects on the proliferation and differentiation of human osteoblast-like MG-63 cells, such as cell viability, alkaline phosphatase (ALP) activity, collagen content, and mineralization, were compared. The chromatograms of the chemical constituents of the two extracts exhibited quite different profiles: quercetin and quercitrin were identified as major peaks in the leaf extract, whereas cinnamtannin B1 and procyanidin isomers were the major peaks for the root extract. Neither extract was cytotoxic at concentrations of < $25{\mu}g/ml$. ALP activity and collagen synthesis-which are markers of the early stage of osteogenesis-in MG-63 cells were significantly increased upon the addition of the root extract compared with the addition of the leaf extract. In contrast, the leaf extract had a more stimulatory effect on mineralization-which is marker of the late stage of osteogenesis-in MG-63 cells than did the root extract. In conclusion, extracts of both leaves and roots of R. crispus stimulated the bone-forming activity of osteoblasts; in particular, the root extract was more effective in the early stage of osteoblast differentiation, while the leaf extract was more effective in the late stage. This difference in anabolic activity may be due to differences in the constituents of the leaves and roots. The leaves and roots of R. crispus appear to complement each other as stimulators of bone formation.

• 한국치위생학회지
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• 제21권5호
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• pp.527-533
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• 2021

연구목적: 본 연구는 대표적인 치아우식 유발 세균인 Streptococcus mutans(S. mutans)에 대한 전기분해 수소수의 항균효과와 치면세균막 억제 효과를 평가하기 위해 실시하였다. 연구방법: BHI 액체배지 상에서 6시간 배양한 S. mutans를 전기분해수소수에 1분 또는 3분 노출시켰다. 전기분해수소수의 증식억제 효과를 확인하기 위해 균주 현탁액을 Mitis Salivarius agar bacitracin(MSB) 배지 상에서 48시간 배양한 후 집락수를 계수하였으며, biofilm formation assay에 따라 crystal violet solution을 30분간 처리하여 치면세균막을 염색하고, 600 nm의 파장에서 흡광도를 측정하여 치면세균막 형성정도를 평가하였다. 연구결과: 전기분해수소수는 S. mutans의 증식과 치면세균막 형성을 유의하게 억제하였으며(p<0.001), 특히 치면세균막 형성의 경우 노출 시간이 증가함에 따라 치면세균막 형성도 유의하게 감소하였다(p<0.05). 결론: 수돗물 전기분해수소수는 S. mutans의 증식과 치면세균막 형성 억제를 통해 치아우식을 효과적으로 예방할 수 있다고 판단된다.

• 한국환경과학회지
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• 제28권2호
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• pp.225-233
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• 2019

In this study, we investigated the in vitro anti-biofilm activities of plant extracts of chives (Allium tuberosum), garlic (Allium sativum), and radish (Raphanus sativus L.) against environment harmful bacteria (gram-positive Staphylococcus aureus and, gram-negative Salmonella typhimurium and Escherichia coli O157:H7). In the paper disc assay, garlic extracts exhibited the highest anti-biofilm activity. The Minimal Inhibitory Concentration (MIC) of all plant extracts was generally higher for gram-negative bacteria than it was for gram-positive bacteria. Gram-negative bacteria were more resistant to plant extracts. The tetrazolium dye (XTT) assay revealed that, each plant extract exhibited a different anti-biofilm activity at the MIC value depending on the pathogen involved. Among the plant extracts tested, garlic extracts (fresh juice and powder) effectively reduced the metabolic activity of the cells of food-poisoning bacteria in biofilms. These anti-biofilm activities were consistent with the results obtained through light microscopic observation. Though the garlic extract reduced biofilm formation for all pathogens tested, to elucidate whether this reduction was due to antimicrobial effects or anti-biofilm effects, we counted the colony forming units of pathogens in the presence of the garlic extract and a control antimicrobial drug. The garlic extract inhibited the E. coli O157:H7 biofilm effectively compared to the control antimicrobial drug ciprofloxacin; however, it did not inhibit S. aureus biofilm significantly compared to ciprofloxacin. In conclusion, garlic extracts could be used as natural food preservatives to prevent the growth of foodborne pathogens and elongater the shelf life of processed foods.

• Asian-Australasian Journal of Animal Sciences
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• 제32권10호
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• pp.1528-1539
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• 2019

Objective: To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from $5^{\circ}C$ to $25^{\circ}C$ on corn silage which was previously fermented at ambient or low temperature. Methods: Whole-plant corn silage was fermented in vacuum bag mini-silos at either $10^{\circ}C$ or $20^{\circ}C$ for two months and stored at $5^{\circ}C$ for two months. The mini-silos were then subjected to additional incubation from $5^{\circ}C$ to $25^{\circ}C$ in $5^{\circ}C$ increments. Bacterial and fungal diversity was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiling and biochemical analysis from mini-silos collected at each temperature. Results: A temperature of $10^{\circ}C$ during fermentation restricted silage fermentation compared to fermentation temperature of $20^{\circ}C$. As storage temperature increased from $5^{\circ}C$ to $25^{\circ}C$, little changes occurred in silages fermented at $20^{\circ}C$, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a high number of enterobacteria and yeasts (4 to $5\;log_{10}$ colony forming unit/g fresh materials) were detected at $15^{\circ}C$ and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at $10^{\circ}C$, no significant changes were observed in most silage characteristics when temperature was increased from $5^{\circ}C$ to $20^{\circ}C$. However, above $20^{\circ}C$, silage fermentation resumed as observed from the significantly increased number of lactic acid bacteria colonies, acetic acid content, and the rapid decline in pH and water-soluble carbohydrates concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from $20^{\circ}C$ to $25^{\circ}C$. Conclusion: Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at $20^{\circ}C$ indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

• Animal Bioscience
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• 제34권3_spc호
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• pp.393-404
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• 2021

Objective: This study compared the catechin composition of different tea byproducts and investigated the effects of dietary supplementation with green tea byproducts on the accumulation of abdominal fat, the modulation of lipid metabolism, and the inflammatory response in red feather native chickens. Methods: Bioactive compounds were detected, and in vitro anti-obesity capacity analyzed via 3T3-L1 preadipocytes. In animal experiments, 320 one-day-old red feather native chickens were divided into 4 treatment groups: control, basal diet supplemented with 0.5% Jinxuan byproduct (JBP), basal diet supplemented with 1% JBP, or basal diet supplemented with 5×106 colony-forming unit (CFU)/kg Bacillus amyloliquefaciens+5×106 CFU/kg Saccharomyces cerevisiae (BA+SC). Growth performance, serum characteristics, carcass characteristics, and the mRNA expression of selected genes were measured. Results: This study compared several cultivars of tea, but Jinxuan showed the highest levels of the anti-obesity compound epigallocatechin gallate. 3T3-L1 preadipocytes treated with Jinxuan extract significantly reduced lipid accumulation. There were no significant differences in growth performance, serum characteristics, or carcass characteristics among the groups. However, in the 0.5% JBP group, mRNA expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were significantly decreased. In the 1% JBP group, FAS, ACC and peroxisome proliferator-activated receptor γ levels were significantly decreased. Moreover, inflammation-related mRNA expression levels were decreased by the addition of JBP. Conclusion: JBP contained abundant catechins and related bioactive compounds, which reduced lipid accumulation in 3T3-L1 preadipocytes, however there was no significant reduction in abdominal fat. This may be due to a lack of active anti-obesity compounds or because the major changes in fat metabolism were not in the abdomen. Nonetheless, lipogenesis-related and inflammation-related mRNA expression were reduced in the 1% JBP group. In addition, dietary supplementation with tea byproducts could reduce the massive amount of byproducts created during tea production and modulate lipid metabolism and the inflammatory response in chickens.

• 디지털융복합연구
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• 제18권12호
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• pp.231-242
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• 2020

코로나 19와 치열한 시장 경쟁으로 공유 경제 플랫폼 업체들은 고객과의 장기적 관계를 형성하는 것이 점차 중요해지고 있다. 이런 맥락에서 본 연구에서는 Airbnb 고객들의 재구매 의사 결정 메커니즘을 살펴보고자 하였다. Airbnb 고객들의 재구매 의도 형성의 선행 요인으로 고객 만족과 브랜드 이미지를 고려하였다. 또한, 가격 공정성, 진정한 경험, 즐거움, Airbnb 신뢰, 호스트 신뢰가 고객들의 재구매 의사 결정에 미치는 영향도 함께 살펴보았다. 본 연구는 Airbnb 이용 고객 154명을 대상으로 연구 가설을 검증하였다. 연구 분석 결과 고객 만족과 브랜드 이미지는 재구매 의도에 유의한 영향을 미쳤으며, 재구매 의도 분산의 62.0%를 설명하였다. 고객 만족에는 즐거움, 진정한 경험, Airbnb 신뢰는 유의한 영향을 미쳤지만, 가격 공정성과 호스트 신뢰는 유의한 영향을 미치지 않았다. 브랜드 이미지는 가격 공정성, 진정한 경험, 즐거움, Airbnb 신뢰에 영향을 미쳤지만, 호스트 신뢰에는 유의한 영향을 미치지 않았다. 본 연구결과를 통해 공유 경제 플랫폼 환경에서 고객들의 재구매 의사 결정에 대한 이해를 증진하여 학문 및 실무적 시사점을 제공해 줄 수 있을 것으로 기대된다.

• 한국학교ㆍ지역보건교육학회지
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• 제22권2호
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• pp.53-64
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• 2021

Objectives: The objective of this study is to understand the factors having effects on the view of marriage of female university students, and also to present the reference data for establishing the measures for having the positive view of marriage of female university students. Methods: An online survey was conducted targeting total 254 female university students of two universities in Gyeonggi region, from October 1 st to November 13th 2020. The results of this study are as follows. Results: First, to the question related to the intent to marry, total 70% of them responded that they had intent to marry. In the time of marriage, they said they would marry when getting financially stable. The 30% of subjects said that they would choose non-marriage because they wanted to continuously enjoy free life and they did not want to bear burden related to childbirth and child-rearing. Second, in the results of analyzing differences in the view of marriage according to the general characteristics, the students with intent to marry showed the higher romantic view of marriage, instrumental view of marriage, and exclusive view of marriage than the students without intent to marry, which showed significant differences. Third, the view of marriage were the factors having the greatest effects on the intent to marry of female university students. Conclusion: Based on such results of this study, it would be necessary to focus on the policies that could positively change the view of marriage of female university students. It would be needed to establish the social·institutional support measures for work-life balance by reducing women's burden of childbirth and child-rearing. To the question about the time of marriage, the most subjects responded that they would do so when the economic ability and stable job were equipped. Thus, there should be the systematic youth employment support system that could help the students to quickly and stably enter society and to become financially independent after graduation. Also, for the formation of positive family relation, it would be necessary to develop·operate the educational programs for forming positive family relation and desirable communication methods for each subject(spouse, parents, children, siblings, and etc.).

• 열처리공학회지
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• 제36권4호
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• pp.198-205
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• 2023

We investigated the effects of Al and Mg on the microstructure and hardness of the coating layer of galvanized steel sheets, by thermodynamic calculations, X-ray diffraction, scanning electron microscopy, and Vickers hardness tests of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers. Regardless of the alloy composition of the galvanizing bath, a Fe-Al layer was observed between the coating layer and steel sheet. The Zn-0.2Al coating layer consists of major h.c.p. Zn phase and minor f.c.c. Al phase. The fraction of f.c.c. Al phase (containing a significant amount of Zn) of the coating layer increases with increasing the chemical composition of Al of the galvanizing bath. The h.c.p. MgZn₂ phase was formed in the Al/Mg-containing Zn-6Al-2Mg and Zn-10Al-5Mg coating layers, forming Zn-Al-MgZn₂ eutectic microstructure. The primary MgZn₂ phase was additionally formed in the Zn-10Al-5Mg coating layers containing high concentrations of Al and Mg. The Vickers hardness values of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers were 59.1 ± 1.2 HV, 161.2 ± 5.7 HV, and 215.5 ± 40.3 HV, respectively. The addition of Al and Mg increased the hardness of the coating layer by increasing the fraction of the Al phase (containing Zn) and MgZn₂ intermetallic compound, which were harder than the Zn phase.