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        검색결과 4,284

        1.
        2024.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The present study aimed to analyze the developmental trajectories of English achievement and exposure time through private education, utilizing univariate and multivariate latent growth curve analysis. This study used a subset of the Gyeonggi Education Panel Study data from 2012 to 2017. The results indicated consistent disparities in the growth of English achievement, depending on the student’s proficiency levels at the starting point. In particular, the early exposure to private tutoring was significantly and closely related to the initial status and the growth trajectory of English achievement. When the sample was classified by urbanicity, the findings suggested that the gap in English achievement was likely to increase over time across the two regions, with a stronger correlation with private tutoring found in urban areas. These results underscore the need for educational intervention for students in less advantageous conditions, and they provide valuable pedagogical implications for teaching English in the Korean EFL context.
        6,100원
        2.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Halictidae 전 세계적으로 3,500종 이상 발견된 큰 그룹이며 사람들의 땀에 이끌리는 특성을 보여 Sweat bee라는 이름으로 불린다. 이번 연 구에서는 꼬마꽃벌과에 속하는 Halictus hedini hedini Blüthgen, 1934을 한국에서 처음으로 보고한다. 본 종의 기재, 분포정보, 그리고 삽화를 제공 한다.
        3,000원
        3.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Sperm quality and the number of sperm introduced into the uterus during artificial insemination (AI) are pivotal factors influencing pregnancy outcomes. However, there have been no reports on the relationship between sperm concentration at AI and sperm quality in Hanwoo cattle. In this study, we examined sperm quality and pregnancy rates after AI using sperm inseminated at different concentrations. Methods: We evaluated the motility, viability, and acrosomal membrane integrity of sperm at different concentrations (10, 15, 18, and 20 million sperm/straw) in 0.5-mL straws. Subsequently, we compared the pregnancy rates after AI with different sperm concentrations. Results: After freeze-thawing, sperm at the assessed concentrations showed similar viability and acrosomal membrane integrity. After AI, cattle in the 10 million group had significantly lower pregnancy rates compared to those in the 18 and 20 million groups. Conversely, there were no statistically significant variances observed between cattle in the 10 and 15 million groups. Conclusions: Sperm at concentrations of 10, 15, 18 and 20 million per straw exhibited comparable motility, viability, and acrosomal membrane integrity. However, a concentration of at least 18 million sperm per straw is required to achieve a consistent rate of pregnancy rate in Hanwoo cattle after AI.
        4,000원
        4.
        2024.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Glutamate-mediated oxidative stress causes neuronal cell death by increasing intracellular Ca2+ uptake, reactive oxidative species (ROS) generation, mitogen-activated protein kinase (MAPK) activation, and translocation of apoptosis-inducing factor (AIF) to the nucleus. In the current study, we demonstrated that corydaline exerts potent neuroprotective effects against glutamate-induced neurotoxicity. Treatment with 5 mmol/L glutamate increased cellular Ca2+ influx, ROS generation, MAPK activation, and AIF translocation. In contrast, corydaline treatment decreased cellular Ca2+ influx and ROS generation. Western blot analysis revealed that glutamate-mediated MAPK activation was attenuated by corydaline treatment. We further demonstrated that corydaline treatment inhibited the glutamate-mediated translocation of AIF to the nucleus. We propose that corydaline is a promising lead structure for the development of safe and effective neuroprotectants.
        4,000원
        5.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the risk of single and combined exposure to microplastics in zebrafish (Danio rerio) through biomarkers, such as survival rate, excretion rate, and histological alterations of organ systems. The experimental groups were the control (Cont.), single microplastics exposure group (MPs, 1.83%/fish total weight (g)), the copper group (Cu, 21.6 μg L-1), and a group with combined exposure to MPs and copper (MPs*Cu). The experiment was conducted with individual exposure (7 days) for MP excretion rate analysis and group exposure (14 days) for biomarker analysis. The daily excretion rate of MPs tended to decrease in a time-dependent manner. The copper concentration in the body was not significantly different between single and combined copper exposure. The degeneration of mucous cells in the skin, capillary dilation of the gill lamella, increased intestinal mucous, hepatocyte hypertrophy, and the degeneration of glomeruli and renal tubules were observed in all exposure groups. These histological alterations showed the highest tendency in the MPs*Cu group. In this study, the changes in biomarkers were attributed to the single effect of copper or the combined effect of copper and MPs rather than being solely influenced by MPs.
        4,600원
        6.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In response to the expanding landscape of the biotechnology industry and the increasing demand for comprehensive drug development as well as the conduct of preclinical and clinical trials, there is a growing need for employment of diverse animal models, including both small and large animals. The focus of this study was on refining ex vivo culture techniques for bioluminescence imaging following administration of intradermal injections in large animals. To examine the feasibility of our approach, varying concentrations of the rFluc protein were administered to rats and live imaging was employed to validate the corresponding levels of expression. Subsequently, following administration of rFluc to mini-pigs, ex vivo analyses were performed on sample tissues to assess the levels of protein expression across different concentrations. In particular, optimal culturing conditions that facilitated the sustained expression of the protein in samples post-euthanasia were identified. Moreover, by employing small animal imaging devices, we were able to capture clear images of the sample plates, which provided evidence of the successful application of our experimental techniques. The findings from this research represent a significant effort toward refining bioluminescence imaging methods tailored for use with large animal models—an imperative facet of contemporary drug development and biomedical research.
        4,000원
        7.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bangladeshi medicinal plants (BMP) have a history of traditional use in treating chronic inflammatory diseases, but a BMP bark’s antioxidant and anti-inflammatory effects remain largely unexplored. This study assessed methanolic extracts’ antioxidant and anti-inflammatory properties from the bark of 15 medicinal plant species native to Bangladesh. The methanol extracts of BMP bark were evaluated for their total antioxidant activity and ability to counteract inflammation induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Among the 15 bark extracts from BMP, Albizia odoratissima (A. odoratissima), Engelhardia spicata (E. spicata), and Shorea robusta (S. robusta) showed the highest total phenolic contents and total antioxidant capacity by effectively scavenging free radicals. In particular, these three bark extracts significantly reduced the mRNA expression of LPS-induced inflammatory cytokines and enzymes inducible by inflammation in macrophages. Also, the mRNA expression of NADPH oxidase 2 was significantly suppressed by the three bark extracts in LPS-induced RAW 264.7 macrophages. These results suggest that out of the 15 bark extracts obtained from medicinal plants in Bangladesh, the extracts from A. odoratissima, E. spicata, and S. robusta exhibit substantial total antioxidant capacity by efficiently scavenging free radicals and also inhibit LPS-induced inflammation in macrophages.
        4,000원
        8.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        토복령은 우수한 항균, 항산화, 항염증 효능을 가진 소재로 알려져 있다. 이러한 토복령(Smilax china)의 추출물의 기능성을 화장품에 적용하기 위한 기초연구로써 토복령에서 발견되는 플라보노이드인 quercetin, catechin, naringenin의 농도별 경피 투과 특성을 조사할 필요성이 있다. Marzulli의 정의에 적 용한 결과 케르세틴의 Kp 값은 0.1 mg/mL에서 "빠름"으로 분류되었고, 0.2 및 0.4 mg/mL에서 "보통"으로 분류되었다. 특히, 농도가 증가함에 따라 투과 속도가 감소하는 경향이 있었다. 나린제닌의 경우 Flux 값은 각각 0.1, 0.2 및 0.4 mg/mL 농도에서 0.69, 1.07 및 1.42 μg/hr/cm²이었으며, 해당 Kp 값은 각각 6.95, 5.34 및 3.56이었다. 나린제닌의 Kp 값은 모든 농도에서 "보통" 범주에 속하며, 케르세틴과 관찰된 것과 같이 농도가 높아짐에 따라 투과 속도가 감소하였다. 카테킨의 경우 Flux 값은 각각 0.1, 0.2 및 0.4 mg/mL 농도에서 0.75, 1.09 및 1.66 μg/hr/cm²이었으며, 해당 Kp 값은 각각 7.55, 5.46 및 4.16이었다. 카테킨의 Kp 값은 모든 농도에서 일관되게 "보통"으로 분류되었다. 여드름 저해능 및 항염증 효능이 우수 한 토복령 추출물의 유효성분인 quercetin, catechin, naringenin의 경피 투과 특성이 보통 이상으로 나타나 기능성 화장품에 사용할 수 있는 우수한 천연물 소재인 것을 확인할 수 있었다.
        4,000원
        9.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        충청남도농업기술원 화훼연구소에서 2021년에 개발된 ‘Pinky Lang’은 분홍색 홑꽃 타입의 스프레이 국화 신품종 이다. ‘Pinky Lang’은 2016년 10월에 육종 하우스 내에서 2016년에 순백색의 진한 녹심이 매력적인 품종으로써 선발 된 백색 홑꽃의 ‘Bodre’ 품종을 방임 수분하여 48개의 종자 를 채취했다. 채취한 종자를 2017년 파종한 뒤 우수개체로 선발되어 2017년부터 2020년까지 4년간 촉성, 억제, 자연개 화 작형별 주년생산성 검정을 수행하여 선발된 우수계통을 ‘SP17-425-01’이라 계통명을 부여하였다. 2020년 최종적으 로 우수한 계통으로써 평가 및 심의를 받은 뒤 ‘충남SP-68 호’로 명명하였고, 당해 년도 12월 직무육성 신품종 선정위원 회를 통과하여 품종명은 ‘Pinky Lang’으로 하였다. ‘Pinky Lang’은 고온기에 화색이 변하지 않고 녹심이 매우 진하며 줄 기가 튼튼한 품종이다. 여름철 흰녹병에도 강하여 고온기 수출 품종으로 적합하다고 판단되었다. ‘Pinky Lang’은 연중 3 작기 재배테스트에서 단일처리 후 개화소요일수는 자연개화 작형 52일, 촉성작형 49일, 억제작형 50일이었고, ‘Yes Luna’ 는 각각 51일, 52일, 52일로 전반적으로 개화소요일수가 짧 았다. ‘Pinky Lang’의 절화장과 줄기굵기는 각각 104.5cm, 4.71mm으로 ‘Yes Luna’가 109.5cm, 4.25mm인 것에 비 해 5cm정도 짧았고 줄기굵기는 0.46mm 더 굵었다. ‘Pinky Lang’의 꽃 크기는 5.6cm이고 ‘Yes Luna’는 6.8cm로 1.2cm 작았다. ‘Pinky Lang’의 한 줄기에 달리는 꽃의 수와 한 송이 당 꽃잎수는 각각 27.7개, 30.9매였고, ‘Yes Luna’ 는 각각 18.0개, 37.0매인 것으로 착화수는 9.7개 많았고 꽃 잎수는 6.1매 적었다. 여름철 재배테스트를 통해 확인해본 결 과 흰녹병 저항성이 높은 경향을 확인하지만, 1~10% 정도의 병반을 보여 완전저항성을 가지진 못하는 것으로 사료된다. 자연개화 작형에서 절화수명의 경우는 24.5일로 ‘Yes Luna’ 에 비해 2.1일 길었다. ‘Pinky Lang’은 과습한 경우 줄기가 연약해질 수 있기 때문에 생장억제제인 Daminozide를 처리 하여 줄기를 강건하게 하고 절화 품질의 균일도를 높여 고온 기 재배에 안정적인 생산이 가능하여 수출할 수 있다.
        4,000원
        10.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The economy of Tanzania relies on agriculture as the main economic activity, because agriculture provides both food and income to the population of the country, especially the rural households. Improvement of market access to crops also increases the productivity. Therefore, in this study, descriptive statistics and statistical analysis of the probit model were used to analyze the factors that determine the market accessibility of small-scale farmers in Chemba, Tanzania. Cross-sectional data collected by the systematic sampling method for 200 corn peasants in Chemba, Tanzania were used. As a result of probit regression analysis, it was found that access to improved seeds and technology had a positive statistically significant effect on the accessibility to the market, while the age of the head of the household, production cost, distance to the market, and household size had a negative statistically significant effect. Therefore, in this study, policy establishment and implementation are recommended. A policy needs to be considered to reduce the transaction costs that eventually allows the farmers to increase the accessibility to markets, enables small-scale farmers to participate in cooperatives, lowers input costs and provides educational programs on quality products to increase their competitiveness in the marketplace.
        4,000원
        11.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 정원에 대한 관심이 증가함에 따라 자생 식물을 활용 하기 위한 연구가 진행되고 있다. 참식나무(Neolitsea sericea (Blume) Koidz).는 관상용뿐만 아니라 목재로도 이용할 수 있 다. 따라서 이 연구는 참식나무를 정원 식물 소재로 활용하기 위한 대량 증식 기술 개발을 위하여 종자의 발아 특성과 저장 특성에 대해 알아보고자 진행하였다. 2022년 11월 2일 제주 지역에서 채집한 종자를 실험에 사용하였다. 종자의 내·외부 형태 관찰을 한 결과, 종자가 탈리되는 시점에 배가 완전히 발 달한 형태를 가지고 있기 때문에 형태적휴면(morphological dormancy, MD)이 없음을 확인할 수 있었다. 수분흡수 실험 을 통하여 참식나무 종자는 72시간 이후 40% 정도의 수분흡수 율을 보여 내과피의 불투성에 의한 물리적휴면(PY, physical dormancy)이 없는 것으로 판단하였다. 채종 후 곧바로 무가 온 온실에 파종하면 이듬해 5월에 약 60%가 발아하였다. 저 온습윤처리 0, 2, 4, 8, 12주 후 25/15°C에 배양한 결과 최 종 발아율은 각각 0%, 0%, 21.1%, 32.6%, 34.7%였다. GA3 를 0, 10, 100, 1000mg·L-1 농도로 처리한 후 25/15°C에서 배양한 결과, 최종 발아율은 각각 0, 14.5, 22.7, 42.2%였다. 따라서 본 실험의 결과 8주 이상의 저온 처리 또는 GA3 처리 를 통하여 어느 정도 휴면을 타파시킬 수 있었다. 이러한 결과 를 통하여 종자는 intermediate PD를 가지는 것으로 판단 된다. 일부 발아하지 않은 종자는 deep PD를 가지고 있는 것 으로 판단하였다. 후숙 처리 실험의 결과 4주 만에 수분 함량 이 2% 이하로 감소하였고 종자는 전혀 발아하지 않았다. 따라 서 종자의 저장 특성 중 recalcittrant 특성을 지닌 난저장성 종자로 보인다.
        4,000원
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Porcine pluripotent stem cells (pPSCs) would provide enormous potential for agriculture and biomedicine. However, authentic pPSCs have not established yet because standards for pPSCs-specific markers and culture conditions are not clear. Therefore, the present study reports comparative pluripotency characteristics in porcine induced pluripotent stem cells (piPSCs) derived from different viral transduction and reprogramming factors [Lenti-iPSCs (OSKM), Lenti-iPSCs (OSKMNL) and Sev-iPSCs (OSKM)]. Methods: Porcine fibroblasts were induced into Lenti-iPSCs (OSKM) and Lenti-iPSCs (OSKMNL) by using Lentiviral vector and Sev-iPSCs (OSKM) by using Sendaiviral vector. Expressions of endogenous or exogenous pluripotency-associated genes, surface marker and in vitro differentiation in between Lenti-piPSCs (OSKM), Lenti-iPSCs (OSKMNL) and Sev-piPSCs (OSKM) were compared. Results: Colonial morphology of Lenti-iPSCs (OSKMNL) closely resembles the naïve mouse embryonic stem cells colony for culture, whereas Sev-iPSCs (OSKM) colony is similar to the primed hESCs. Also, the activity of AP shows a distinct different in piPSCs (AP-positive (+) Lenti-iPSCs (OSKMNL) and Sev-iPSCs (OSKM), but AP-negative (-) LentiiPSCs (OSKM)). mRNAs expression of several marker genes (OCT-3/4, NANOG and SOX2) for pluripotency was increased in Lenti-iPSCs (OSKMNL) and Sev-iPSCs (OSKM), but Sev-iPSCs (OSKM). Interestingly, SSEA-1 of surface markers was expressed only in Sev-iPSCs (OSKM), whereas SSEA-4, Tra-1-60 and Tra-1-81 were positively expressed in Lenti-iPSCs (OSKMNL). Exogenous reprogramming factors continuously expressed in Lenti-iPSCs (OSKMNL) for passage 20, whereas Sev-iPSCs (OSKM) did not express any exogenous transcription factors. Finally, only Lenti-iPSCs (OSKMNL) express the three germ layers and primordial germ cells markers in aggregated EBs. Conclusions: These results indicate that the viral transduction system of reprograming factors into porcine differentiated cells display different pluripotency characteristics in piPSCs.
        4,900원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aligned with the recent shift in fruit consumption trends, there is a growing increase in the cultivation of these fruits. Thus, various types of small fruits, including blueberries, have recently been introduced and cultivated in Korea. According to the data, there has been a notable uptick in blueberry farming, in stark contrast to the decline in cultivation of black raspberries, black chokeberries, and blackcurrants. New varieties of blueberries continue to be introduced and cultivated, aligning with the recent consumption trends and are expected to be consistently cultivated in the future. Despite the decrease in the other berries, health benefits associated with all berries have ignited growing consumer interest, resulting in domestic and international market expansion. In conclusion, this research underscores the importance of identifying plant varieties that are well-suited to Korea's climatic conditions, validating efficient cultivation strategies, and establishing robust distribution networks to foster sustainable development in the berry industry.
        4,000원
        14.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to reset the maximum residue limit (MRL) for didecyldimethylammonium chloride (DDAC) in broiler chickens. The disinfectant containing DDAC (10%, w/w) was diluted 160 times and evenly sprayed on the bodies of twenty-four broiler chickens at a rate of 15 mL per day per bird for 7 days. After the disinfectant treatment, tissue samples were collected from six broiler chickens at 0.25, 1, 3 and 5 days, respectively. Residual DDAC concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 2.0~10.0 μg/kg), recoveries (86.9~118.6%), and coefficient of variations (<19.98%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In all tissues except for liver, DDAC was detected more than LOQ at 5 days after the disinfectant treatment. In liver tissues, DDAC was detected more than LOQ at 3 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal period of DDAC in poultry tissues was established to 26 days. In conclusion, the developed analytical method is sensitive and reliable for detecting DDAC in poultry tissues. When DDAC disinfectant is sprayed on a poultry house in the presence of broiler chickens, it is necessary to keep the disinfectant from contacting the body of the livestock.
        4,000원
        15.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a seed propagation protocol of Hemerocallis taxa native to the Korean Peninsula. In this study, the seed dormancy types were classified. The germination traits of H. thunbergii, H. dumortieri, H. hakuunensis, and H. hongdoensis were also characterized. The initial embryo to seed length ratio (E:S ratio) in seeds of the four Hemerocallis species was between 0.80 and 0.90 at harvest, however, the E:S ratio did not increase until just before germination. Thus, seeds of the four Hemerocallis species had no morphological dormancy (MD), and at least 84% of seeds of all tested species germinated at 25/15℃ under light within 30 days. The lower the incubation temperature, the lower the germination rate of seeds of the four Hemerocallis species. However, the temperature range for germination was expanded due to old stratification. Gibberellin treatment increased the germination rate or germination speed at a relatively low temperature of 15/6℃. However, this treatment did not improve the germination rate as much as the temperature at 25/15℃. Under 15/5℃ of incubation, cold stratification increased the final germination percentage and rate/speed and expanded the temperature range for germination from high to low (25/15℃ → 15/6℃). This indicates that the seeds have a conditional dormancy (CD) that germinates in a narrow temperature range. In conclusions, the four Hemerocallis seeds exhibited nondeep physiological dormancy.
        4,300원
        16.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the fungicidal efficacy of weakly acidic hypochlorous acid water (WAHW) against Microsporum canis (M. canis) and its therapeutic effect on M. canis-infected mouse skin. WAHW was produced by a WAHW generation module. A fungicidal efficacy test by the broth dilution method was used to determine the lowest effective concentration of the WAHW. The lowest effective concentration of WAHW was less than 10 ppm. For T-1, T-2, and T-3, 30 ppm of WAHW was applied to the infected skin once, twice, and three times a day, respectively, and for T-4, 50 ppm of WAHW was applied once a day. On the 3rd day after the initiation of treatment, skin scores in all of the WAHW-treated groups were significantly decreased compared to those in the positive control group (PC) (p<0.05), and there were no significant differences compared to the normal control (NC). The area of the infected skin in all of the WAHW-treated groups was significantly decreased compared to PC from the first day after the initiation of WAHW treatment (p<0.05). The results showed that WAHW had a fungicidal efficacy on M. canis at less than 10 ppm, and it was effective in improving skin symptoms when 30 ppm of WAHW was applied to the M. canis-infected area once a day for five days or 50 ppm of WAHW was applied once a day.
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