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        검색결과 266

        41.
        2018.12 구독 인증기관 무료, 개인회원 유료
        Exosomes are Nano-sized lipid vesicles secreted from mammalian cells containing diverse cellular materials such as proteins, lipids, and nucleotides. Multiple lines of evidence indicate that in saliva, exosomes and their contents such as microRNAs (miRNAs) mediate numerous cellular responses upon delivery to recipient cells. The objective of this study was to characterize the different expression profile of exosomal miRNAs in saliva samples, periodically isolated from a single periodontitis patient. Unstimulated saliva was collected from a single patient over time periods for managing periodontitis. MicroRNAs extracted from each phase were investigated for the expression of exosomal miRNAs. Salivary exosomal miRNAs were analyzed using Affymetrix miRNA arrays and prediction of target genes and pathways for its different expression performed using DIANA-mirPath, a web-based, computational tool. Following the delivery of miRNA mimics (hsa-miR-4487, -4532, and -7108-5p) into human gingival fibroblasts, the expression of pro-inflammatory cytokines and activation of the MAPK pathway were evaluated through RT-PCR and western blotting. In each phase, 13 and 43 miRNAs were found to be differently expressed (|FC| ≥ 2). Among these, hsa-miR-4487 (|FC|=9.292005) and hasmiR- 4532 (|FC|=18.322697) were highly up-regulated in the clinically severe phase, whereas hsa-miR-7108-5p (|FC|= 12.20601) was strongly up-regulated in the clinically mild phase. In addition, the overexpression of miRNA mimics in human gingival fibroblasts resulted in a significant induction of IL-6 mRNA expression and p38 phosphorylation. The findings of this study established alterations in salivary exosomal miRNAs which are dependent on the severity of periodontitis and may act as potential candidates for the treatment of oral inflammatory diseases.
        4,000원
        42.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 MLS(moving least squares) 차분법의 1차 미분 근사함수를 바탕으로 시간에 따른 수치해석이 가능한 해석기법을 제시한다. 오직 1차 미분 근사함수로만 지배방정식을 이산화했으며, 근사함수를 조립하는 형태로 전체 시스템 방정식을 구성하여 차분법으로 이산화된 운동방정식이 유한요소법(finite element method)과 유사한 모습을 갖게 되었다. 운동방정식을 시간적분하기 위해서 중앙차분법(central difference method)을 사용하였다. 유한요소 알고리즘을 통해서 MLS 차분법과 유한요소법의 고유진동 해석을 수행하였으며, 두 해석결과를 비교하였다. 또한, 동적해석 결과를 기존의 2차 미분 근사함수를 활용한 해석결과와 함께 도시함으로써 제안된 수치기법의 정확성을 검증하였다. 1차 미분 근사함수를 조립하는 과정에서 해석결과의 떨림현상이 억제되었으며 상대적으로 균일한 응력분포를 구할 수 있었다.
        4,000원
        44.
        2018.07 구독 인증기관·개인회원 무료
        Climate change is expected to become a considerable threat to life on earth and it already affects certain tourism destinations like mountain regions and costal destinations. For instance, Switzerland is regarded as one of the most popular ski destination worldwide, but today’s ski resorts in Switzerland is facing significant difficulties as weather condition has been particularly harsh for the ski industry in the last years. While ski resorts start to use various rate fences to implement differential pricing, there is relatively little research how their customers perceive these new pricing approaches. Therefore, this study tried to identify how various rate fences adopted in ski resorts, including the use of weather forecasts in differential pricing, are perceived by customers and consequently which of them could be successfully implemented to provide the industry with long-term benefits. In particular, this study focused on the effect of framing and gender on price perception. The study found that female are generally more sensitive to differential pricing and have the tendency to perceive it as less fair.
        45.
        2018.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Effects of annealing temperature on the microstructure and mechanical properties through thickness of a Cu-3.0Ni- 0.7Si alloy processed by differential speed rolling are investigated in detail. The copper alloy with a thickness of 3 mm is rolled to a 50 % reduction at ambient temperature without lubricant and subsequently annealed for 0.5 h at 200-900 oC. The microstructure of the copper alloy after annealing is different in the thickness direction depending on the amount of the shear and compressive strain introduced by the rolling; the recrystallization occurs first in the upper roll side and center regions which are largely shear-deformed. The complete recrystallization occurs at an annealing temperature of 800 oC. The grain size after the complete recrystallization is finer than that of the conventional rolling. The hardness distribution of the specimens annealed at 500-700 oC is not uniform in the thickness direction due to partial recrystallization. This ununiformity of hardness corresponds well to the amount of shear strain in the thickness direction. The average hardness and ultimate tensile strength has the maximum values of 250 Hv and 450 Mpa, respectively, in the specimen annealed at 400 oC. It is considered that the complex mode of strain introduced by rolling directly affects the microstructure and the mechanical properties of the annealed specimens.
        4,000원
        46.
        2018.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        대부분의 다른 종양과 마찬가지로, 담낭암의 영상의학적 평가는, 발견 혹은 감별진단과 그 이후의 병기 결정으로 나누어 볼 수 있다. 담낭암의 진단 및 평가에 사용되는 영상 검사 는 주로 transabdominal US, CT, MRI, PET 그리고 EUS 등이 있다. 이러한 영상학적 검사를 적절하게 사용하면 조기 담낭암의 진단율 및 감별진단에 도움이 된다. 본고에서는 각 형태에 따른 감별진단을 다루고, 다음 단계로 병기 결정에 있어서 영상의 역할과 한계를 고찰하고자 한다.
        4,000원
        47.
        2017.10 구독 인증기관·개인회원 무료
        β-glucan is a safe and highly potent biological response modifier that nutritionally activates the immune response through the Macrophage, Dendritic and additional immune cells to yield various therapeutic effects. Shiitake mushrooms (Lentinula edodes) contanining β-glucans may be beneficial for human health; they have been used in the treatment of cancer, hypertension, and high cholesterol levels. The effect of different substrates and various developmental stages (mycelium growth, primordium appearance, and fruiting-body formation) on β-glucan production in the edible mushroom L. edodes was studied. The cap of the mature mushroom showed the highest β-glucan activity, and β-glucan activity seemed to be influenced somewhat by some well-known inducers or sawdust. In this study, we utilized five strains (JMI 10022, 10036, 10077, 10079, 10080) of L. edodes regardless of origin and growth conditions. This experiment showed that the expression of β-glucan was induced by glucose bond, and increased with the growing of L. edodes. Quantitatively, reverse transcription PCR utilized pairs of primers specific for β-glucan gene expression shows that expressed genes were most commonly indentified during the process of fruiting-body formation. We suggest that the results will provide valuable information to assist L. edodes industry.
        48.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Salt stress is one of the most limiting factors that reduce plant growth, development and yield. However, identification of salt-inducible genes is an initial step for understanding the adaptive response of plants to salt stress. In this study, we used an annealing control primer (ACP) based GeneFishing technique to identify differentially expressed genes (DEGs) in Italian ryegrass seedlings under salt stress. Ten-day-old seedlings were exposed to 100 mM NaCl for 6 h. Using 60 ACPs, a total 8 up-regulated genes were identified and sequenced. We identified several promising genes encoding alpha-glactosidase b, light harvesting chlorophyll a/b binding protein, metallothionein-like protein 3B-like, translation factor SUI, translation initiation factor eIF1, glyceraldehyde-3-phosphate dehydrogenase 2 and elongation factor 1-alpha. These genes were mostly involved in plant development, signaling, ROS detoxification and salt acclimation. However, this study provides new molecular information of several genes to understand the salt stress response. These genes would be useful for the enhancement of salt stress tolerance in plants.
        4,000원
        49.
        2017.05 구독 인증기관·개인회원 무료
        The coat color of mammals is determined by the melanogenesis pathway, which is responsible for maintaining the balance between black-brown eumelanin and yellow-reddish pheomelanin. The melanogenesis-associated genes controlling pigmentation act as a complex and interact with each other to cause phenotypic and genotypic variations in cattle. That the MC1R genotype of Korean native cattle with dark muzzle was e/e or E+/e, while the genotype of Korean native cattle with light muzzle was E+/E+, which is a variant of the MC1R genotype in the Korean native cattle. Especially, the MC1R expression type is shows how much pigmentation, important factor in deciding its status in the coat and nose colours. However, information regarding the coat or nose colours-associated gene regulation of korean cattle is not yet unknown. Therefore, in this study was to investigate the expression patterns of melanogenesis-associated genes in black dot nose(korea brindle cattle) and normal nose(korea native cattle). Using microarray clustering and real-time polymerase chain reaction techniques, we analysed that the expression of genes involved in the mitogen-activated protein kinase (MAPK) and Wnt signaling pathways is distinctively regulated in the dark and light muzzle tissues. Differential expression of tyrosinase was also noticed, although the difference was not as distinct as those of MAPK and Wnt. We hypothesize that emphasis on the MAPK pathway in the Korea brindle cattle induces eumelanin synthesis through the activation of cAMP response elementbinding protein and tyrosinase, while activation of Wnt signaling counteracts this process and raises the amount of pheomelanin in the native cattle. Regarding the increasing interest in the genetic diversity of cattle stocks, genes we identified for differential expression in the brindle cattle vs. native cattle may serve as novel markers for genetic diversity among cows based on the coat and muzzle color phenotype.
        50.
        2017.04 구독 인증기관·개인회원 무료
        Honey bee swarming is a natural phenomenon that occurs by changes of colony (i.e. population size and queen condition) and environment conditions. As cuticular hydrocarbons (CHCs) are known to be involved in the communication between honey bee nest-mates, we investigated and compared the CHC profiles of worker bees from individual colonies of 9-days before swarming (PPSC), a day before swarming (PSC), swarming (SG) and remaining (non-swarming) (RG). A total of 53 CHCs were identified by GC-MS, among which 11 compounds showed significantly differential expression patterns between swarming states. Before swarming (between PPSC and PSC), detection levels of 4 CHCs were significantly different, suggesting that production of some CHCs changed prior to swarming for swarming preparation. Six CHCs were deferentially produced between PSC and RG. The differential profiles of CHCs with respect to different swarming states are currently under investigation.
        51.
        2016.10 구독 인증기관·개인회원 무료
        The small brown planthopper (SBPH), Laodelphax striatellus, is one of the most serious pest insects of rice plants because it can transmit the rice stripe virus (RSV) which often causes significant reduction of yield in the field. Buprofezine is an effective insect growth regular (IGR) pesticide to control planthoppers, however, since the use of buprofezine for more than a decade, it has caused a certain resistance of SBPH. To survey the responses of SBPH to buprofezine, we exposed 4th instar SBPH to 200 ppm buprofezine by dipping method, and extracted total RNA for RNA-seq by Illumina platform. The quality filtered raw reads of cDNA obtained from experimental and control SBPH were subjected to Bowtie2 followed by eXpress computer program to compare the differential gene expression which will be important information for pest control methods using RNAi.
        52.
        2016.07 구독 인증기관·개인회원 무료
        We study the differential effects of a variety of WOM and mass communication activities on the means and on the variances of individual preference parameters. Analyzing the effects of communication on the means of individual preference parameters provides useful information regarding how much WOM and mass communication activities increase or decrease consumers’ preference parameters. Such a study helps us better understand how communication activities influence consumer heterogeneity. This raises a new question: “Do WOM and mass communication activities make consumers homogeneous or heterogeneous in terms of their product preferences?” This important question has not been previously addressed in the marketing literature. We propose a two-level choice model using a hierarchical Bayesian probit to incorporate the differential effects of mass and WOM communication activities, and the proper interaction between communication activities and product attributes. Using actual movie choice data, we analyze the effects of WOM communication activities compared to those of mass communication activities. Furthermore, we measure the differential effects of communication activities and the interaction effects between communication and product attributes. Based on the empirical analysis, we provide relevant managerial guidelines about communication activities.
        53.
        2016.07 구독 인증기관·개인회원 무료
        With the rapid development of digital technologies and the Internet, the boundaries between countries are shrinking and markets are becoming global (Oh et al., 2016). Simultaneously, cross-border online shopping is another trend that has spread across the world, and global e-commerce has now become a reality (Johnson et al., 2003; Moore, 2015). However, in prior studies related to eWOM, the national culture has received little attention among the numerous factors that could adjust the effect of eWOM (Christodoulides et al., 2012). In addition, in the real world, although individuals are frequently exposed to combined eWOM messages containing both positive and negative information about the same product, most previous studies on eWOM have focused on the one-sided eWOM valence. There are not many empirical studies on the influence of the two-sided eWOM valence on consumers’ persuasions. Thus, Study I examines the attitude effect of the two-sided eWOM valence from a cross-cultural perspective, particularly on the basis of the differences in thinking styles between the Easterners and Westerners. For this, we use a 2[Valence: positive/negative, negative/positive] x 2[Culture: East (South Korea), West (United States)] factorial design. To classify the culture, the thinking style was measured as a within-group variable. As a result, the interaction effect between valence and culture (nation) was significant. Specifically, in the East (South Korea), no significant difference existed in the changes in brand attitude depending on the two-sided eWOM valence, whereas brand attitude changes from a negative/positive presentation order in the West (United States) were significantly larger than the positive/negative presentation order. Study II demonstrates the mediated moderation effect of perceived cognition congruency in a cross-cultural setting for explaining the underlying mechanism. Drawing on the cognitive fit theory, we present a two-sided eWOM-consumers’ perceived cognition congruency proposition: the two-sided eWOM valence that matches the information processing order consumers habitually have would facilitate the favorable comprehension (reflected by perceived cognition congruency) and assessment (reflected by changes in brand attitude) of the reviews. As a result, the two-sided eWOM valence indirectly affects brand attitude changes by mediating perceived cognition congruency. This valence directly affects the brand attitude changes in the Westerner (United States) group, which has an analytical thinking style. However, the direct and indirect effects of two-sided eWOM valence on brand attitude changes are not significant in the Easterner (South Korea) group, which has a holistic thinking style. This examination might explain why differences in the changes in brand attitude between the Easterners and Westerners were revealed through the twosided eWOM valence, thus providing in-depth insights into consumer responses for the valence. This study expands the diversity of studies conducted on the characteristics of the two-sided eWOM. Furthermore, it is expected to provide a strategic direction and practical implications for two-sided eWOM-driven information management by organizations.
        54.
        2016.07 구독 인증기관·개인회원 무료
        The purpose of this study is to present theoretical and experimental evidence for a niche strategy for small and medium online shopping malls to run business against large famous shopping malls prevailing the E-commerce market. For this, the present study demonstrates how chronic construal levels of consumers may affect their alternative choice for online shopping via various contexts (Experiment 1-3) and categories (Experiment 3-5). This series of experiments suggests that consumers with high construal level can be defined as a group that is relatively less susceptible to reputation of the shopping malls. Thus, strategically targeting this group of consumers will help small and medium-sized online malls lacking store reputation to mitigate their competitive disadvantage. Based on both existing literature and the experimental results as above, this research discusses possible methods for small and medium-sized online shopping malls to target high-construal segmentation.
        55.
        2016.06 구독 인증기관 무료, 개인회원 유료
        Tooth development shows dynamic morphological changes from the stages of cap to hard tissue formation and is strictly regulated during development. In the present study, we compared expression and localization of 3 major enamel matrix proteins in rats: amelogenin, enamel and ameloblastin. DD-PCR and RT-PCR revealed differential expression of the major proteins from the cap stage to root stage. Immunofluorescence staining results indicated that amelogenin was not detected in either inner enamel epithelium or reduced enamel epithelium, but highly immunoreactive in preameloblasts and ameloblasts; in addition, it was sporadically expressed in preodontoblasts abutting preameloblasts. Ameloblastin expression was also observed in not only differentiated ameloblasts but also osteoblasts. Immunoreactivity to ameloblastin in ameloblasts was strong in Tomes' processes. Enamelin was exclusively localized along the entire newly formed and maturing enamel. Enamelin was largely localized in near Tomes' processes and enamel rods in maturing enamel. Alendronate treatment resulted in down-regulation of amelogenin and ameloblastin at both transcription and translation levels; whereas, enamelin expression was unchanged in response to the treatment. These results suggested that amelogenin, ameloblastin and enamelin might be implicated in cell differentiation, adhesion of ameloblasts to enamel and enamel crystallization during enamel matrix formation, respectively.
        4,000원
        56.
        2016.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Appropriate thermo-mechanical properties of nickel-based superalloys are achieved by heat treatment, which induces precipitation and solid solution hardening; thus, information on the temperature ranges of precipitation and dissolution of the precipitates is essential for the determination of the heat treatment condition. In this study, thermal analyses of nickelbased superalloys were performed by differential scanning calorimetry method under conditions of various heating rates of 5, 10, 20, or 40K/min in a temperature range of 298~1573K. Precipitation and dissolution temperatures were determined by measuring peak temperatures, constructing trend lines, and extrapolating those lines to the zero heating rate to find the exact temperature under isothermal condition. Determined temperatures for the precipitation reactions were 813, 952, and 1062K. Determined onset, peak, and offset temperatures of the first dissolution reaction were 1302, 1388, and 1406K, respectively, and those values of the second dissolution reaction were 1405, 1414, and 1462K. Determined solvus temperature was 1462K. The study showed that it was possible to use a simple method to obtain accurate phase transition temperatures under isothermal condition.
        4,000원
        57.
        2016.04 구독 인증기관·개인회원 무료
        Honey bee swarming is a naturally occurring phenomenon under the conditions of population increase, climate change and pollen deficit. However, unexpected swarming usually results in loss of bee colony, it poses a considerable trouble in bee keeping. In an attempt to search for molecular markers that can predict the swarming behavior, transcriptional profiling was conducted and compared between the heads of swarming group and the remaining group in the same honey bee colonies. A total of 25,551 transcripts were initially identified and 1,144 differentially expressed genes between the two groups were sorted by FC2 (fold change) cut-off value. Several transcripts, including 6 apidermin (structurally novel cuticular protein)-related, 16 cuticular and 3 odorant binding proteins, showed lower expression levels in the swarming group compared with the remaining group (FC range of –2.17 to –667.48, -2.04 to –54.34 and -2.08 to –21.34 respectively). Pathway analyses are currently in progress to understand the physiological and metabolic differences between swarming and remaining groups of honey bees.
        58.
        2016.03 구독 인증기관 무료, 개인회원 유료
        The tongue has 4 kinds of papillae, which are filiform, fungiform (FU), foliate (FO) and circumvallate papilla (CV). Tongue papillae except filiform papilla include taste buds. The papillae differ in taste sensitivities, likely due to differential expression of taste receptors. In this study, we evaluated differences in the expression levels of taste receptors in FU, FO and CV. Male DBA2 mice, 42-60 days old, were used in the study. Messenger RNAs were extracted from the murine epithelial tissues including FU, FO and CV. Cloned DNAs were synthesized by reverse transcription. Quantitative PCRs (qPCRs) were performed to determine mRNA expression levels of taste receptors. Results of qPCR revealed that the relative expression levels and patterns were different among FU, FO and CV. All three type 1 taste receptors were expressed FU, FO and CV at varying relative expression levels. All 35 kinds of type 2 taste receptors showed higher expression in FO and CV than in FU. Tas2r108 and Tas2r137 showed the two highest expression levels in all tested papillae. The differential expression levels and patterns of taste receptors among the three papillae could contribute to the different physiological sensitivities by tongue areas. Additional studies such as in situ hybridization or taste receptor cell activity recording is necessary to elucidate the functional relationship between expression levels of taste receptors and taste sensitivity.
        4,000원
        59.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in degradation of the extracellular matrix. MMP-8 has been reported to be involved in the degradation of collagen in progression of dental caries. MMP-13 was found to be expressed in both normal and caries pulp, implying its involvement in the pathogenesis of dental caries. Methods: Four extracted teeth were used. They were categorized into four grades according to caries progression. Three sections were prepared from each separated crown and root. Immunofluorescence of the FITC of the MMP-8 and 13 in coronal and radicular dentin was analyzed by confocal microscopy. Results: Immunofluorescence signals that were indicative of MMP-8 were observed both in radicular and coronal dentin in the sound, C1 and C3 carious teeth. In C2 carious teeth, immunofluorescence signals that were indicative of MMP-8 were observed only in radicular dentin. Immunofluorescence signals that were indicative of MMP-13 were observed both in radicular and coronal dentin in the sound teeth. In C1, C2 and C3 carious teeth, immunofluorescence signals that were indicative of MMP-13 were not observed both in radicular and coronal dentin. Conclusion: Immunofluorescence signals revealed that MMP-8 and 13 were present in coronal and radicular dentin, and was differently expressed as caries progressed.
        4,000원
        60.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기후변화는 국내 해충상의 변화에 영향을 주는 주요 요인 가운데 하나로 알려지고 있다. 특히 지구 온난화 모델에 따라 남방계 곤충의 서식 지 확대가 예상되고 있다. 휴면 기작을 가지고 있지 않은 파밤나방(Spodoptera exigua)과 배추좀나방(Plutella xylostella)은 시설재배지를 중심으 로 국내에서 월동이 가능한 것으로 알려지고 있다. 그러나 두 해충은 계절적 발생 양상에서 뚜렷한 차이를 보여주었다. 배추좀나방은 이른 봄철과 가을기간에 발생하고 여름 기간 중에는 발생하지 않았다. 반면에 파밤나방은 늦은 봄철에 나타나기 시작해 가을까지 지속적으로 발생하였다. 본 연구는 이러한 두 남방계 곤충이 계절적 발생 차이를 보이는 것이 이들이 갖는 고온에 대한 감수성 차이에 기인한 것으로 가정하였다. 이 가설을 증명하기 두 곤충의 내열성을 비교 분석하였다. 동일한 열처리(42℃)에서 배추좀나방 유충은 40 분 노출에 100% 사망률을 보인 반면, 파밤나방 은 대부분의 유충이 80 분의 노출에서도 생존하였다. 이러한 내열성은 두 곤충 모두 이들의 발육시기에 따라 상이했다. 배추좀나방은 4령 유충과 성충이 가장 높은 내열성을 보인 반면, 파밤나방은 1령 유충에서 가장 높게 나타냈다. 두 곤충 모두는 37℃에서 30 분간 전 처리 후 고온에 노출시 키면 생존율이 뚜렷하게 증가했다. 이러한 내열성유기는 두 곤충 모두 혈림프의 글리세롤 함량 증가와 관련성을 보였다. 또한 파밤나방의 경우는 열충격단백질의 발현도 증가하였다. 따라서 이상의 결과는 여름기간 배추좀나방의 발생이 없는 것은 이 곤충의 고온에 대한 높은 감수성에 기인 된 것으로 보이고, 반면에 파밤나방은 비교적 높은 내열성을 보유하여 여름 기간에도 발생을 지속시킨 것으로 해석되었다.
        4,000원
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