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        검색결과 147

        41.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effect of dietary lysine and gamma-linolenic acid(GLA) levels on growth performance, carcass traits, and meat quality in finishing pigs. Pigs were provided with feed containing two different levels of lysine(0.45% and 0.75%) with three different levels of gamma-linolenic acid(0.0, 0.3, and 0.6%). Average daily gain(ADG) was significantly lower (p<0.01) in pigs provided with the lower level of lysine. In contrast, feed/gain(p<0.01), diet cost/gain(p<0.05), and intramuscular fat(p<0.01) were all significantly higher in pigs fed the lower level of lysine. Similarly, meat color scores(CIE L*, a*, and b*) and cooking loss were significantly higher(p<0.01) in pigs fed the lower level of lysine, whereas shear force(kg/2.5 inch2)was not affected by dietary lysine. The addition of GLA had no significant effect on any of the parameters measured. The results indicate that providing pigs with 0.45% lysine in their diet may help to increase intramuscular fat content, allowing the industry to produce pork products that meet consumer needs in Korea.
        4,000원
        42.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Most previous studies on dinoflagellates in Korean coastal areas were conducted without morphological descriptions and illustrations of the observed dinoflagellates. This indicates that the species and diversity of dinoflagellates may have been respectively misidentified and underestimated in the past, probably due to cell shrinkage, distortion and loss caused by sample fixation. This study provides information on the morphological observations of four dinoflagellate orders (Prorocentrales, Dinophysiales, Gonyaulacales and Gymnodiniales) from Jangmok Harbour in Jinhae Bay, Korea. The unfixed samples were collected weekly from December 2013 to February 2015. A total of 13 genera and 30 species were identified using light and scanning electron microscopy, although some samples were not clarified at the species level. Harmful dinoflagellates, Prorocentrum donghaiense, Tripos furca, Alexandrium affine, A. fundyense, Akashiwo sanguinea and Cochlodinium polykrikoides, were identified based on the morphological observations. The results also reflect the occurrence and identification of dinoflagellates that had not been previously recorded in Jangmok Harbour.
        4,000원
        43.
        2016.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We improve the energy conversion efficiency (ECE) of a dye sensitized solar cell (DSSC) by preparing a working electrode (WE) with localized surface plasmon resonance (LSPR) by inducing Au thin films with thickness of 0.0 to 5.0 nm, deposited via sputtering. Field emission scanning electron microscopy and atomic force microscopy were used to characterize the microstructure of the blocking layer (BL) of the Au thin films. Micro-Raman measurement was employed to confirm the LSPR effect, and a solar simulator and potentiostat were used to evaluate the photovoltaic properties, including the impedance and the I-V of the DSSC of the Au thin films. The results of the microstructural analysis confirmed that nano-sized Au agglomerates were present at certain thicknesses. The photovoltaic results show that the ECE reached a value of 5.34% with a 1-nm thick-Au thin film compared to the value of 5.15 % without the Au thin film. This improvement was a result of the increase in the LSPR of the TiO2 layer that resulted from the Au thin film coating. Our results imply that the ECE of a DSSC may be improved by coating with a proper thickness of Au thin film on the BL.
        4,000원
        44.
        2016.07 구독 인증기관 무료, 개인회원 유료
        Cross-buying refers to the customer action of buying additional products and/or services from the same provider (Valentin 2004). With the belief that cross-buying enables firms to increase profit from existing customers, firms have steadily placed greater emphasis on cross-selling strategies for profitability. To date, numerous studies show that cross-buying behavior of customers has a positive effect on firm profitability. Business reality, however, offers a different perspective; namely, that high levels of cross-buying may not always be linked to firm profitability. For example, Best Buy (an electronics retailer in the United States) has identified approximately 20% of its customers as unprofitable in spite of them purchasing multiple items (McWilliams 2004). Shah, Kumar, Qu, and Chen (2012) found that customers who persistently exhibit certain types of behavior (e.g., excessive service requests, high levels of returning products, lower levels of revenue growth, promotion maximizers) are unprofitable even though they purchased more than one product category.The aforementioned research implies that cross-buying can exert a negative impact on profitability, thereby calling for further examination of cross-buying behavior. It is conceivable that a repeated purchase propensity (contrasted with a cross-buying propensity) concentrated on a single brand is more profitable. Therefore, our primary objective in this paper is to identify a more beneficial type of customer among those who tend to patronize a limited number of brands versus those who tend to patronize a variety of brands, using a one-dimensional model (brand dispersion index). In addition, the second goal of this research is to investigate the boundary conditions where cross-buying will not lead to an increase in sales (unprofitable cross-buying conditions). As two moderating factors that weaken a customer’s crossbuying propensity and a firm’s sales (frequency and transaction size of firms), we consider (1) promotion dependency and (2) spending limiter condition. We use transaction data that include partners in various industries such as gasoline stations, convenience stores, banks, restaurants, and online shopping malls, covering forty-seven categories. Because multiple partners in many categories are available, this allows us to study whether a customer’s cross-buying level in the current period (t) affects the customer’s purchase frequency and transaction size in the subsequent period (t+1). The observation period for the data set extends over three years. Findings from this study indicate that a high level of cross-buying at period t has a positive impact on increasing customer frequencies and transaction sizes in the subsequent (t+1) period. This means that cross-buying has the potential to increase the firm’s profitability. Customers who show a high level of cross-buying propensity tend to exhibit higher levels of loyalty than customers who concentrated on limited brands. Firms should find ways to induce customers with low cross-buying propensity to increase crossbuying. Regarding moderating effects, promotion dependency and spending growth (decline vs. stagnation), spending growth has a considerable moderating effect on the relationship between cross-buying propensity and a customer’s transaction size. Specifically, the effect of cross-buying on transaction size weakens when spending is shrinking. This result makes an important contribution to cross-buying research. If customers showing a high level of cross-buying do not increase their spending level, they may be merely switching to other brands in the program under a fixed budget. So while the rate of crossbuying seems to increase, profit might not increase. The findings from this study imply that it is crucial to target and motivate customers who tend to use various brands and contribute to sales to do more cross-buying instead of suggesting cross-buying to random customers. The promotion dependency, however, turns out to not have significant moderating effects on the relationship between the customer’s propensity to cross-buying and the customer’s purchase frequency and transaction size. For marketing purposes, it is important to consider which customers are more profitable among those who tend to do cross-buying among multi-brands versus those who tend to purchase repeatedly in a limited number of brands. This research provides a solution with a one-dimensional index, the brand dispersion index. Whether cross-buying is shown to be a positive or negative impact on sales, the results are meaningful in implementing customer relationship management. Regardless of the direction in the level of crossbuying, both directions provide a solution to allocate marketing resources. For instance, if the propensity for cross-buying increases sales, the firm should implement marketing strategies to encourage people to use a variety of brands by adding new brands. If repeat purchases increase sales, the company should concentrate on certain brands that customers use most frequently. In addition, by finding the conditions that do not increase sales (e.g., spending limiter condition), it makes marketing practitioners think that cross-buying does not always bring positive results. Overall, the findings from this study are that it is crucial to motivate and target customers who tend to use various brands and contribute to sales to do crossbuying activity, instead of promoting cross-buying to random customers. Conceptual Framework Figure 1 provides an overview of our framework for the relationship between brand dispersion and visiting frequency and transaction size of customers. Specifically, we hypothesize how customer frequencies and transaction sizes in time t+1 will be influenced by customer brand dispersion levels (the extent that customer transactions occur across a broad range of brands) in time t. In addition, we examine the moderating influence of two customer specific variables: (1) degree of promotion dependency and (2) spending limits.
        3,000원
        45.
        2016.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We prepared polymethyl methacrylate (PMMA) beads with a particle size of 80 nm to improve the energy conversion efficiency (ECE) by increasing the effective surface area and the dye absorption ability of the working electrodes (WEs) in a dye sensitized solar cell (DSSC). We prepared the TiO2 layer with PMMA beads of 0.0~1.0 wt%; then, finally, a DSSC with 0.45 cm2 active area was obtained. Optical microscopy, transmission electron microscopy, field emission scanning electron microscopy, and atomic force microscopy were used to characterize the microstructure of the TiO2 layer with PMMA. UV-VIS-NIR was used to determine the optical absorbance of the WEs with PMMA. A solar simulator and a potentiostat were used to determine the photovoltaic properties of the PMMA-added DSSC. Analysis of the microstructure showed that pores of 200 nm were formed by the decomposition of PMMA. Also, root mean square values linearly increased as more PMMA was added. The absorbance in the visible light regime was found to increase as the degree of PMMA dispersion increased. The ECE increased from 4.91% to 5.35% when the amount of PMMA beads added was increased from 0.0 to 0.4 wt%. However, the ECE decreased when more than 0.6 wt% of PMMA was added. Thus, adding a proper amount of PMMA to the TiO2 layer was determined to be an effective method for improving the ECE of a DSSC.
        4,000원
        46.
        2016.04 구독 인증기관·개인회원 무료
        Oat! It entices us with its awesome components such as β-glucan and unsaturated fatty acid. This study was performed to investigate the changes of flour size distribution, pH, moisture content, Hunter color value, polyphenol, protein, flavonoid, lipid rancidity, β-glucan content and sensory evaluation of covered and naked oat flour that heated at 80, 120, 160 and 200℃. It was roasted for 5min to begin with, followed by complete cool, and for 10min at the second time. There was some difference in flour size distribution before and after of roasting. With increasing temperature, oat was more broken finely. For the Hunter b value representing the blackish color of the surface, after oats went through a roasting process, one went through until 160℃ showed same color statistically. Moisture content declined more as the roasting temperature became higher. As for pH, its range of variation was small from 6.2 to 6.6. While a polyphenol was on the reduction, protein was on the rise by the increase of temperature. In total, a flavonoid was declined at 80℃ but increased from 120 until 200℃ compared to control. A MAD (malonaldehyde) related with lipid acidification was statistically identical until 160℃ and sharply risen at 200℃. Roasting conditions had significant effect on β-glucan content. A covered oat’s β-glucan was declined as opposite to naked oat’s β-glucan with temperature being increased. Variation in sensory evaluation such as color, taste, smell and preference was observed. There is no statistically significant difference in specimens heated at 160℃ and 200℃ of covered and naked oat in sensory evaluation(p<5%). All things considered including MDA, β-glucan content and sensory evaluation, a optimum temperature for roasting oat to develop processed goods was verified as about 160℃.
        47.
        2016.04 구독 인증기관·개인회원 무료
        Biological control has been tried for integrated pest management. It is often comparable, safe, and environment-friendly, making itself an alternative for chemical agents. Filamentous microorganisms, i.e., fungi and streptomystes, produce many kinds of useful metabolites, and some of them have been developed as a biocontrol agent. However, they still have a long way because of the concern of manufacturing cost. Therefore, process development was intensively studied to meet cost-effectiveness. Operating conditions of bioreactor, e.g., agitation and aeration, had an effect on biological and physiological responses such as mycelial morphology, oxygen and nutrient transfer. Understanding relationship between operating parameters and microbial responses in terms of growth, substrate and oxygen consumption, and production yield was critical for process development. This study dedicated to build strategies for mass production of biological control agent using aerobic filamentous microorganisms.
        48.
        2015.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study examined the effects of learner-initiated noticing through comparison and teacher-initiated noticing through grammar instruction on EFL middle school learners' English writing process and uptake. For the study, 18 second-year middle school students with intermediate-high English proficiency were divided into three groups. After the first writing composition, one group (Group C) underwent a comparison stage, in which they compared their original writings and reformulated versions. Another group (Group I) received reactive grammar instruction on the four most frequent types of grammar errors, while the other group (Group IC) underwent both stages. All three groups revised their original writings in the next stage. To examine the learners' cognitive processes, think-aloud protocols were analyzed. The results showed that Group IC performed better in uptake than the other two groups, while no major differences were found between Groups I and C. This suggests that a mixture of learner-initiated noticing and teacher-initiated noticing influenced the learners' uptake.
        5,500원
        49.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Three growing wethers were used to investigate the differences in nitrogen (N) retention, blood plasma metabolite concentration and energy-yielding nutrient supply to muscle and adipose tissue. The wethers were fed one of three diets: timothy hay with concentrate (THD), Italian ryegrass with concentrate (IRD), and rice straw with concentrate (RSD) for 11 days. The experimental diets were adjusted to the animals to provide 100 g of daily gain. The triglyceride (TG) concentration of blood plasma in arterial and portal veins was higher with THD and IRD than with RSD. Conversely, the available amount of TG in tissues was higher with IRD. The daily amount of glucose and non-esterified fatty acids (NEFA) supplied to muscle tissue and adipose tissue was numerically higher with THD than IRD or RSD. Although N retention did not differ among the diets, it was numerically higher with THD than with IRD or RSD. The results suggest that the difference in the amount of glucose and NEFA delivered to muscle tissue may reflect the N retention in response to forage based diets.
        4,000원
        50.
        2014.07 구독 인증기관 무료, 개인회원 유료
        Although the role of Guanxi in the Chinese business to business (B2B) market as a form of relationship marketing has received increasing attention in recent years, few empirical studies have explicitly distinguished between Guanxi and relationship marketing. Westerners typically consider Guanxi as unethical, but foreign-invested enterprises (FIEs) may have some difficulty in fully practicing relationship marketing in China without considering the influence of Chinese culture. In this regard, this study is guided by the following research question: “In China, should foreign-invested enterprises (FIEs) adopt Guanxi instead of relationship marketing in the B2B market?” In this study, we first provide an overview of previous research on Guanxi, focusing on the fundamental differences between Guanxi and relationship marketing. We then provide an empirical analysis of the differential effects of Guanxi and relationship marketing on firm performance by investigating 295 FIEs in the Chinese B2B market. The results suggest that Guanxi and relationship marketing are not trade-off options in today’s Chinese market. Guanxi and relationship marketing have synergetic effects on firm performance, that is, they have differential effects based on the mode of market entry and the type of competitor. Guanxi is more likely to influence firm performance for collaboration based entry firms rather than entry without collaboration firms, whereas relationship marketing is more likely to influence firm performance when FIEs’ main competitors are foreign firms than when they are local firms.
        6,600원
        51.
        2013.10 구독 인증기관·개인회원 무료
        Proteinaceous insecticidal proteins, Cry proteins, from Bacillus thuringiensis (Bt) are insecticidal proteins that are highly active against several species of Lepidoptera. Thus, cry genes encoding these Cry proteins have been widely applied for construction of transgenic crops resistant to pest insects. In this study, through the 3D structure prediction and accompanying mutagenesis study for the Mod-Cry1Ac, 7 and 16 amino acid residues from domain I and II, respectively, responsible for its insecticidal activity against larvae of Spodoptera exigua and Ostrinia furnacalis were identified. We used site-directed mutagenesis to improve the insecticidal activity of Mod-Cry1Ac, resulted 31 mutant cry genes. These mutant cry genes encodes potent insecticidal proteins in the form of crystalline protoxins of 95 kDa. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. When the insecticidal activities of these mutant Cry proteins against to larvae of P. xylostella, S. exigua and O. furnacalis were assayed, they showed higher or similar insecticidal activity compared to those of Cry1Ac and Cry1C. Especially, Mutant-N16 is considered to have the potential for the efficacious biological insecticide since it showed the highest insecticidal activity.
        52.
        2013.04 구독 인증기관·개인회원 무료
        Crystals of proteinaceous insecticidal proteins, Cry proteins, produced by Bacillus thuringiensis (Bt) have been generally used to control insect pests. In this study, through the 3D structure prediction and accompanying mutagenesis study for the Mod-Cry1Ac, 7 and 16 amino acid residues from domain I and II, respectively, responsible for its insecticidal activity against larvae of Spodoptera exigua and Ostrinia furnacalis were identified. To construct novel cry genes with enhanced insecticidal activity, we randomly mutated these 23 amino acid sequences by in vitro muti site-directed mutagenesis, resulting in totally 24 mutant cry genes. For further characterization, these mutant cry genes were expressed as a fusion protein with polyhedrin using baculovirus expression system. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. When the insecticidal activities of these mutant Cry proteins against to larvae of P. xylostella and S. exigua were assayed, they showed higher or similar insecticidal activity compared to those of Cry1Ac and Cry1C. Especially, among them Mutant-N16 showed the highest insecticidal activity against to both of P. xylostella and S. exigua. Therefore, Mutant-N16 is considered to have the potential for the efficacious biological insecticide.
        53.
        2013.03 구독 인증기관 무료, 개인회원 유료
        Ovarian cancer is the most lethal world-wide gynecological disease among women due to the lack of molecular biomarkers to diagnose the disease at an early stage. In addition, there are few well established relevant animal models for research on human ovarian cancer. For instance, rodent models have been established through highly specialized genetic manipulations, but they are not an excellent model for human ovarian cancer because histological features are not comparable to those of women, mice have a low incidence of tumorigenesis, and they experience a protracted period of tumor development. However, the laying hen is a unique and highly relevant animal model for research on human ovarian cancer because they spontaneously develop epithelial cell-derived ovarian cancer (EOC) as occurs in women. Our research group has identified common histological and physiological aspects of ovarian tumors from women and laying hens, and we have provided evidence for several potential biomarkers to detect, monitor and target for treatment of human ovarian cancers based on the use of both genetic and epigenetic factors. Therefore, this review focuses on ovarian cancer of laying hens and relevant regulatory mechanisms, based on genetic and epigenetic aspects of the disease in order to provide new information and to highlight the advantages of the laying hen model for research in ovarian carcinogenesis.
        4,000원
        54.
        2013.03 구독 인증기관 무료, 개인회원 유료
        Artificial insemination (AI) has been performed widely in swine industry using fresh liquid sperm instead of frozen type of sperm. However fresh sperm are not able to preserve more than three days with optimal motility and other sperm parameters for the successful fertilization, since in vitro stored sperm has an oxidative stress that resulted increase of abnormality and acrosome reation. To overcome these major problems, novel preservative formulation is needed to neutralize the oxidative stress and to provide suitable physiological environment for sperm in in vitro. In this study, naturally derived substances such as Poncirus trifoliate (Trifoliate orange), Garcinia mangostana (Mangosteen), pig placenta and testis extracts were tested as sperm preservative agents. Placenta extracts (PE), trifoliate orange extracts (TOE), testes extracts (TE) and mangosteen extracts (ME) were applied to analyze specific parameters for sperm motion characteristics individually and combinatorial. Each individual extract treatment can accelerate the sperm motility but noticeably TOE, TE and ME treatments exhibited the considerable and significant preservation of sperm motility. PE, TE and ME showed a significant (p<0.05) increase in ALH after one week. Further we evaluated the five different combinations of these extracts on sperm motility and its motion characteristics. Surprisingly even after one week ME, TOE and TE combination significantly preserved the sperm motility about 75%. It is noteworthy that unlike individual extract treatment, combination of ME, TOE and TE simultaneously protect the sperm motility and its motion characteristics. Taken together these data conclude that addition of ME, TOE and TE can be effective for preservation of pig sperm.
        4,000원
        58.
        2012.10 구독 인증기관·개인회원 무료
        Varieties of Bacillus thuringiensis (Bt) crystal proteins, Cry proteins, have so far been found as one of the most successful biological control agents which are safe to natural environments for a long time. Recently, cry genes encoding these Cry proteins have been widely applied for construction of transgenic crops resistant to pest insects. In this study, through the 3D structure prediction and accompanying mutagenesis study for the Mod-Cry1Ac, 7 and 16 amino acid residues from domain I and II, respectively, responsible for its insecticidal activity against larvae of Spodoptera exigua and Ostrinia furnacalis were identified. To construct novel cry genes with improved insecticidal activity, we randomly mutated these 23 amino acid sequences by in vitro muti site-directed mutagenesis, resulting in totally 24 mutant cry genes. For further characterization, these mutant cry genes were expressed as a fusion protein with polyhedrin using baculovirus expression system. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. In the further study, we plan to investigate their insecticidal activity against Plutella xylostella, S. exigua and O. furnacalis larvae.
        59.
        2012.10 구독 인증기관·개인회원 무료
        We developed and characterized five polymorphic microsatellites of Nilaparvata lugens from hybridization method using biotin enrichment strategy and two polymorphic microsatellites from Next Generation Sequencing. Also 11 microsatellites that developed by Sun et al. (2011) are employed to carry out genetic analysis of N. lugens in Southeast Asia. The number of alleles per locus ranged from 2 to 12 with an average of 4.63 alleles per locus. The mean observed heterozygosity of the eleven populations ranged from 0.031 to 0.938 and the expected hetetrozygosity ranged from 0.031 to 0.881. Signifiant genetic differentiation was detected among the three N. lugens populations as the FST ranged from 0.028 (Cheong Do and Ha Long) to 0.161 (CH and BN). The results of microsatellite marker suggested that found N. lugens migrated to Korea at least two times in different period or once. Genetic distance of N. lugens between Korea and Hi Pong were mostly closed and genetic distance of Ha Long and HCM were relatively closed. In this study, development of microsatellites should facilitate the study of future population genetics of N. lugens, and eventually elucidate the route of N. lugens migration to Korea. Thus, combining satisfactory microsatellite markers and intensive surveillance methods in paddy field could be easy to understand to the N. lugens migration mechanism.
        60.
        2012.09 구독 인증기관 무료, 개인회원 유료
        Interferon induced transmembrane protein-1 (Ifitm-1) has been reported to have an important role in primordial germ cell formation, and it has expressed in female reproductive organ. In the present study, Ifitm-1 gene expression was identified in testes and all part of epididymis using western immunoblot and immunohistochemistry. Interestingly, Ifitm-1 expression was observed on the head of spermatozoa. To investigate the role of Ifitm-1 gene expression in behavior of spermatozoa after acrosome reaction, fresh sperm was incubated with calcium ionophore to induce acrosome reaction, whereas the expression of Ifitm-1 was not altered after the acrosome reaction. Then to identify the effect of Ifitm-1 in sperm motility and other seminal parameters, different concentration of Ifitm-1 antibody was incubated with spermatozoa, and seminal parameters were assessed using computer-assisted semen analysis (CASA). Interestingly, motility, progressive, and VAP were increased in the sperm with Ifitm-1 antibody treated compared to rabbit serum, however other parameters such as straightness were not changed. In order to identify the functional significance of Ifitm-1 in fertilization, capacitated spermatozoa were pre-incubated with anti- Ifitm-1 antibody and subsequently examined the ability to adhere to mouse oocytes. However, any defection or alteration in sperm-egg fusion was not found, Ifitm-1 antibody treated or non-treated spermatozoa showed a normal penetration. Although the precise role of Ifitm-1 in sperm motility and following fertilization need to be elucidated, this study suggests that the activation of Ifitm-1 on the sperm may enhance the motility of spermatozoa in mice.
        4,000원
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