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        검색결과 153

        21.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Singil Stream, flowing into an artificial lake, Lake Shihwa (South Korea), experiences a strong anthropogenic pressure with continuous organic matter (OM) inputs from rural, urban, and industrial areas. In this study, we investigated suspended particulate matter (SPM) and streambed sediments collected along the Singil Stream in 2014 and 2016, by applying a dual element approach (δ13C and δ15N) to identify OM sources. The SPM and streambed sediment samples from the indusrial area showed higher organic carbon and nitrogen concentrations (or contents) than those from the other areas, with distinctively lower δ15N values. Accordingly, our dual element approach indicates that the industrial area was the predominant OM source influencing OM quality and thus water quality of the Singil Stream flowing into Lake Shihwa during the study periods. However, further studies are necessary to better constrain OM sources in the Singil Stream since OM sources from the industrial area appear to be complex.
        4,000원
        24.
        2018.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Transient ischemic attack (TIA) indicates high risk for major stroke and is considered a medical emergency. Diffusion-weighted imaging (DWI) enables detection of acute ischemic lesions. The clinical significance of DWI positive lesions in TIA is obscure and its prevalence, clinical features are not established. Therefore, we performed a clinical, etiological and prognostic analysis through a cross-sectional analysis of 235 TIA patients, grouped according to presence of DWI lesion. Clinical features, underlying risk factors for stroke, outcome and rate of recurrence were analyzed. 3 months follow-up of modified Rankin Scales (mRS) were done with telephone survey. DWI positive lesions were present in 14.0% of patients. Etiological factors significantly associated with DWI lesions in TIA patients were male sex (p = 0.038), stroke history (p = 0.012) and atrial fibrillation (p < 0.001). Presence of at least one medium or high risk of cardioembolism from TOAST classification were not associated with lesions when excluding association to atrial fibrillation (p = 0.108). Clinical features showed no significant difference. Whether the patients had lesion-positive DWI was not related to an increase in mRS score during the hospital stay or at the 3-month follow-up after discharge. Future studies should include multi-center samples with large numbers, considering each unique medical environment. Routine acquisition of follow-up DWI for proper evaluation of the tissue-based definition of TIA should also be considered.
        4,000원
        25.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Leg length discrepancy (LLD) leads to many musculoskeletal disorders and affects daily activities such as walking. In the majority of the population, mild LLD is a common condition. Nevertheless, it is still controversy among researchers and clinicians on the effects of mild LLD during gait, and available studies have largely overlooked this issue. Objects: The purpose of the present study is to investigate the effects of mild LLD on the gait parameters and trunk acceleration. Methods: A total of 15 female and male participants with no evidence of LLD of >.5 ㎝ participated in the present study. All participants walked under the following two conditions: (1) The non-LLD condition, where the participants walked in shoes of the same heel height; (2) A mild LLD condition induced by wearing a 1.5 ㎝ higher heel on the right shoe. The GAITRite system and tri-axial accelerometer were used to measure gait parameters and trunk acceleration. To compare the variation of each variable, a paired t-test was performed. Results: Compared to the non-LLD condition, step time and swing phase were significantly increased in the mild LLD condition, while stance phase, single support phase, and double support phase significantly decreased in the short limb (p<.05). In the long limb of the mild LLD condition, single support phase significantly increased, while swing phase significantly decreased (p<.05). Furthermore, significant decrease in the gait velocity and cadence in the mild LLD condition were observed (p<.05). In the comparison between both limbs in the mild LLD condition, the step time and swing phase of the short limb significantly increased compared with the long limb, while step length, stance phase, and single support phase of the long limb significantly increased compared with the short limb (p<.05). Additionally, trunk acceleration of all directions (anterior-posterior, medial-lateral, vertical) significantly increased in the mild LLD condition (p<.05). Conclusion: The results of the present study demonstrate that mild LLD causes altered and asymmetrical gait patterns and affects the trunk, resulting in inefficient gait. Therefore, mild LLD should not be overlooked and requires adequate treatment.
        4,000원
        26.
        2018.11 구독 인증기관·개인회원 무료
        Prolactin is an anterior pituitary hormone involved in various physiological phenomenon including reproduction. The prolactin receptor (PRLR) is detected in diverse tissues such as brain, ovary, placenta and uterus in several mammalian species. A total of 227 pigs [Korean native pigs (KNP) 27; Landrace pigs 29; Korean native pigs x Landrace F1 91; Nanchuckmacdon pigs 80] were used to investigate the allele frequency difference of the prolactin receptor (PRLR) gene among the four pig lines. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with Alu I restriction enzyme was used to determine the genotypes of PRLR. Frequencies of PRLR alleles among the four different pig lines were not significantly different (Chi-square=3.94, DF=3, P=0.27). A total of 40 Nanchuckmacdon pigs were used to investigate the effect of the prolactin receptor (PRLR) gene on total number of piglets born (TNB), number of piglets of alive (NBA) using general linear model implemented in MINITAB software. For TNB, the AB genotype had higher genotypic value (10.61) than the values of AA (9.83) and BB (10.30). Likewise, the AB genotype had higher genotypic value (8.96) than the values of AA (8.18) and BB (8.90) for NBA. However, these associations of the PRLR gene with TNB and NBA were not statistically significant. In conclusion, it is necessary to increase the sample size for investigating the effect of the PRLR gene on TNB and NBA in pigs.
        27.
        2018.11 구독 인증기관·개인회원 무료
        Blood types in pigs are divided into two types, A and O type. It is important to select and breed O-type pigs that have no hematologic rejection, because the blood type of the donor is an important factor causing immune rejection in xenotransplantation. Therefore, the gene that determines the blood type is GGTA1(glycoprotein, alpha-1,3-galactosyltransferase 1), which generally belongs to the ABO blood group. This study was carried out to develop a simple and accurate method by analyzing the structure of GGTA1 gene which determines blood type. A primer was designed to allow easy identification of the blood type of the target in the first and second deletion regions of intron 7 to distinguish between the A and O genotypes. That is, for the purpose of identifying the blood type using length difference after the PCR, the forward and reverse primers were designed in the highly conservative region. As a result, a pair of primers were prepared and PCR amplification was performed to distinguish three types of genotypes, AA, AO, and OO, using the length difference by electrophoresis. Using the above primers, the parents and their offspring were compared with each other to confirm the correct genetic pattern. And, in four pig breeds, the genes were amplified and the genotype could be correctly identified. In this study, we could diagnose the blood type of AA, AO, OO genotype of pigs by using primer of INDEL region. Especially, since it is possible to diagnose the genotype by the length difference, it is possible to diagnose it quickly and accurately from the gene amplification to the genotype reading
        28.
        2018.11 구독 인증기관·개인회원 무료
        Transplantation of stem cells, such as mesenchymal stem cells (MSCs), is a promising strategy for treating several types of intractable disorders. Mechanistically, it could not only replace damaged cells by direct contribution, but also establish an anti-inflammatory or immunomodulatory microenvironment. However, the cellular mechanisms underlying molecular and biological properties of stem cells during ex vivo expansion and also after transplantation in pathological environments remain largely elusive. We recently developed the cyanoacrylamide-based coumarin derivatives (Fluorescent real-time thiol tracer; FreSHtracer*) reversibly react with glutathione for monitoring of glutathione levels in living stem cells. These probes revealed that glutathione levels are heterogeneous among subcellular organelles and among individual cells and show dynamic changes and heterogeneity in repopulating stem cells depending on oxidative-stress or culture conditions. Importantly, a subpopulation of stem cells with high-glutathione levels exhibited increased self-renewal and migration activities in vitro and showed improved therapeutic efficiency in treating asthma. Furthermore, employing a novel combination of longitudinal intravital confocal fluorescence imaging and microcystoscopy in living animals, we investigated the distributions and properties of transplanted multipotent MSCs derived from human embryonic stem cells at single-cell resolution in real-time by performing confocal imaging of bladder tissues in a rat model of IC/BPS for up to 6 months post-transplantation. These novel real-time monitoring strategies demonstrate the novel molecular insight for maintaining stem cell functions and also enhance understanding of the in vivo behaviors of the engrafted stem cells, which is crucial to determine the efficacy and safety of stem cell-based therapies. This strategy may facilitate the translation of various stem cell-based approaches into clinical practice.
        29.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구 결과, 숙성처리는 지황의 비소화성 당류의 분해로 환원당이 증가하고, 쓴 맛의 원인인 카탈폴을 감소시킴으로서 지황의 소화성과 단맛의 증가에 긍정적인 영향을 줄 수 있을 것으로 생각되며, 비소화성 당류로부터의 환원당 증가와 카탈폴 감소를 위한 최적 온도는 각각 50℃와 30~40℃이었다. 따라서 본 연구에서 제안하는 숙성처리가 낮은 소화성과 쓴맛으로 인해 활용성이 낮은 지황의 소화성과 관능적 품질 개선에 활용될 수 있을 것으로 판단된다.
        4,000원
        30.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed variations of learning stress by comparing the salivary cortisol levels of students who participated in Earth Science inquiry activities. The cortisol concentrations between the pre- and post-inquiries of the sample of 34 university students, who had taken the course of ‘Basic Earth Science and Experiments’, were analyzed. The Earth Science inquiries consisted of geology and astronomy activities. The observational geology activities consisted of a session of ‘structure contours and map patterns’ and the cognitive astronomy activities consisted of a session of ‘representations of horizontal and equatorial coordinates’. These Earth Science inquiry activities were found to cause students to have anxiety, and the thought processes that these activities involved were found to cause learning stress. The variations in cortisol concentrations of students increased by 1.6±5.9 ng mL−1 after conducting observational activities in geology compared with 2.1±6.2 ng mL−1 after doing cognitive activities in astronomy. The analysis of the observational activities in the geology inquiry activities indicated that they were consistent with low levels of learning stress. Conversely, the analysis of the cognitive activities in the astronomy inquiry activities showed significant individual variations in cortisol concentrations. Furthermore, individual differences in cognitive ability were reflected in the astronomy inquiry activities. While students, who received high scores, exhibited low levels of stress in the geology inquiry activities, they showed high levels of stress in the astronomy inquiry activities. It was concluded that, in the case of students with high scores in the study, the level of learning stress increased due to the raised anxiety in cognitive inquiry activities. In contrast, students, who received low scores in the study, exhibited high levels of stress in the geology inquiry activities, and low levels of stress in the astronomy inquiry activities.
        4,300원
        31.
        2018.07 구독 인증기관·개인회원 무료
        Sponsored search advertising is the largest form of the Internet advertising in terms of advertising expenditure. Although researchers have studied various issues in the sponsored search advertising, they have mainly focused on managing each keyword separately without considering the relationship between different keyword queries. However, this is not consistent with the industry practice, and fails to account for the consumers’ search patterns. Online retailers carry various brands and products from competing manufacturers and their advertising strategy needs to include multiple keywords consistent to their product line. Similarly, consumers sequentially search and click on a number of different keywords at different stages of their decision journey. While it is important to understand advertisers’ bidding strategy and consumers’ search behavior in an integrated manner, the previous research in marketing has less explored the interplay between advertisers bids and consumer searches in a multiple keyword setting. We address these issues and offer practical implications on how advertisers should optimally and simultaneously bid on multiple keywords, incorporating consumers click behavior on multiple keywords. This study empirically examines the relationships between consumers’ clicks and online retailers’ bidding strategy on multiple keywords of competing manufacturer brands of 242 retailers. Our data contain daily information of the most popular keywords in a running shoes category on different search advertising metrics. Based on the consumer decision journey and purchase funnel framework, we classify the keywords into different groups following a hierarchical structure of the generic, brands, and models levels and examine the relationships between different keyword groups. Our main findings show that consumers usually click on multiple keywords of each manufacturer brand in a manner consistent with the consumer decision journey or purchase funnel framework, and that consumers are less likely to click on keywords across competing brands. However, online retailers’ bidding pattern is different from consumers’ click behavior in that they simultaneously bid on multiple keywords of competing manufacturer brands at the different hierarchy levels. In sum, our results provide online retailers useful insights to improve their keyword management practice, based on the relationship we identified on the consumer clicks and advertiser bids.
        32.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Currently, dramatic change had led to the growth of the distribution environment and the retailer’s distribution channel. This change had shifted the ‘single channel’ to ‘multi channel’, and from ‘cross channel’ to ‘omni channel’. While fashion companies using omni channel are rapidly growing, few research regarding omni channel had been done in academic field. In this study, we examined the influence of omni channel characteristics on consumers’ perceived risk as well as consumers’ perceived risk toward attitude and intention to use omni channel. We surveyed 696 male and female respondents aged 20 to 40 who lived in Seoul and the metropolitan area. Using AMOS 20.0, factor analysis, reliability analysis, and structural equation model analysis were performed to verify the model of this study. The results were as follows. First, omni channel’s instant connectivity, location-based provability, interactivity, and entertainment factors did not decrease impacts on the perceived risk related to privacy and annoyance. Second, omni channel’s instant connectivity and entertainment did not increase effects on the perceived financial risk, and location-based provability and interactivity did not increase effect on perceived financial risk. Third, the perceived risk concerning omni channel did not decrease on consumer attitude toward omni channel. Fourth, consumer attitude toward omni channel influenced the intention to use omni channel significantly.
        4,600원
        34.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        현재 농가에서 이용되고 있는 보광등과 난방등의 특성을 조사하고 하우스내 기상 환경과 절화장미의 개화와 품질에 미치는 영향을 알아보기 위해 실험을 수행하였다. 보광등으로는 LED등(light emitting diode lamp, LED), 메탈할라이드등(metal halide lamp, MH), 고압나트륨등(high pressure sodium lamp, HPS)을, 난방등으로는 나노탄소섬유 적외선등(nano-carbon fiber infrared lamp, NCFI)을 절화장미 재배상 위에 설치하였다. 그 결과 LED와 NCFI의 광도는 각각 6.8μmol·m-2·s-1과 0.4μmol·m-2·s-1으로 매우 낮은 반면, MH와 HPS는 79 ~ 100μmol·m-2·s-1 범위로 높은 편이었다. 또한 LED와 MH는 적외선역에 파장이 없어 발열량이 거의 없었으나, HPS와 NCFI는 적외선역에 파장이 많아 발열이 많은 것으로 나타났다. 동일한 공간에서 칸막이로 실험구간을 나누어 실험이 수행되었음에도 불구하고 MH, HPS, NCFI에 의해 온도는 2°C 정도 상승되는 결과를 얻었으나, 습도에서는 처리간 차이가 보이지 않았다. 광도에 상관없이 모든 전등들은 절화장미의 개화를 촉진시켜 무처리구에 비해 적게는 5 ~ 7일, 많게는 12 ~ 14일 개화가 촉진되는 것으로 나타났다. 광량이 충분한 봄철에는 전조처리에 의해 개화소요일수가 짧아지는 만큼 절화장도 대조구보다 짧아졌지만, 광량이 부족한 겨울철에는 전조처리에 의해 절화장이 길어져 품질이 향상되는 결과를 얻을 수 있었다.
        4,000원
        36.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oxidative stress is one of common cause of fatty changes in the liver. Antioxidant capacity was confirmed in various vegetables including black radish (Raphanus sativus L. var niger). Fermentation of vegetables using Lactobacillus plantarum has been known to generate bioactive components. This study was conducted to determine if fermented black radish (FBR) ameliorates oxidative liver injury induced by CCl4 in rats. To accomplish this, FBR (250 and 500 mg/ kg) was orally administered to rats for 7 consecutive days, single CCl4 (1.5 mL/kg) treatment or no treatment orally. Serum chemistry at 24 hours after CCl4 injury showed that FBR (500 mg/kg) significantly reduced the level of both alanine aminotransferase and aspartate aminotransferase in CCl4 exposed rats. Moreover, FBR treatment significantly increased radical-scavenging effects in livers with the reduction of lipid peroxidation in CCl4 exposed rats. Histopathologic findings including Kupffer cell activation in the liver of each group matched those of serum chemistry. Collectively, black radish, through fermentation, exerts hepatoprotective capacity in CCl4 induced liver injury in rats through anti-oxidation.
        4,000원
        38.
        2017.10 구독 인증기관·개인회원 무료
        An increased use of organic phosphorous based chemical pesticides in domestic and overseas agriculture has resultedin emergence of tolerant strains of insect pests. These pests have spread throughout South Korea and are responsible forsignificant reduction in crop yields. Furthermore, as yet there is no effective way of controlling these insects or the damageresulting from pest infestation. To this end, we are attempting to develop biological control based methods to protectcrop plants against insect pests. A screen for biocontrol agents conducted in five farms that were heavily infested bynematodes in 2015-2016 identified Aspergillus niger F22 strain that was very effective against root-knot nematode. Afour-time treatment with A. niger F22 at an internal of ten days was able to reduce nematode population by 70-90%compared to untreated controls. The biocontrol agent was also more effective compared to ograno-phosphorus based pesticide,which caused a 30% reduction in nematode population. Notably, the extract (suspension concentrate) prepared from A.niger culture was equally effective in controlling the root-knot nematode and is currently being developed as a marketableproduct under the brand name “NAMAFREE”.
        39.
        2017.10 구독 인증기관·개인회원 무료
        Diets rich in flavonoid-containing foods are sometimes associated with cancer, neurodegenerative and cardiovascular disease prevention. β-glucan, one of the most important bioactive compounds in medicinal mushrooms, is used to boost the immune system, diabetes and cancer. In this study, we aimed to determine the content of two flavonoid compounds (naringenin and naringin) and β-glucan in Flammulina velutipes and Flammulina velutipe-gold strain. The naringenin, naringin, and β-glucan components from the Flammulina velutipes and Flammulina velutipe-gold strain were measured by the HPLC analysis. As a result, the contents of naringenin, naringin, and β-glucan were found to be much higher in Flammulina velutipe-gold strain than Flammulina velutipe. From the above results, we may suggest that Flammulina velutipe-gold strain might have useful as a material for functional food and pharmaceutics fir the pathological process of various human diseases.
        40.
        2017.10 구독 인증기관·개인회원 무료
        Ganoderma lucidum has been reported to have various biological activities including antioxidant activity. The objective of this study was to compare the antioxidant effects between Ganoderma lucidum (GL) and antler-shaped fruiting body of Ganoderma lucidum (AGL). In vitro antioxidant activities were examined by 2,2-diphenyl-picrylhydrazyl hydrate (DPPH) and 1,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities of GL and AGL ethanol extracts. In the DPPH and ABTS radical scavenging activities of GL and AGL ethanol extracts, antioxidant activities of AGL extracts (IC50, 66.94 μg/ml and 131.23 μg/ml) was showed higher than GL extracts (IC50, 83.93 μg/ml and 164.54 μg/ml). Total polyphenol content and total flavonoid content (38.00 g GAE/kg extract and 11.58 g NE/kg extract) of AGL were found higher as compared to GL (34.23 g GAE/kg extract and 3.46 g NE/kg extract). In summary, the results of this study demonstrate that AGL extracts had higher antioxidant activities to GL.
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