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        검색결과 1,207

        481.
        2015.03 구독 인증기관 무료, 개인회원 유료
        Antibiotics have been used to prevent disease, promote growth rate, and improve feed efficiency. However, the use of antibiotics in livestock has been restricted worldwide due to problems such as bacterial resistance. Therefore, probiotics among alternatives to antibiotics have gained attention in the livestock feed industry these days. This study was conducted to investigate the effects of dietary supplementation with probiotic 379D on safety, growth rate, and feed efficiency. In this study, bacterial strain 379D was isolated from soil and identified as a Bacillus sp. according to 16S rRNA sequence analysis. In an in vitro test, in-gel activity assay and antimicrobial susceptibility test were conducted to evaluate 379D. In an in vivo study, 379D was administered at concentrations of 0.1% and 1% to broiler chickens for 28 days. The results of in-gel activity assay and antimicrobial susceptibility test showed that strain 379D had broad spectrum antimicrobial activity. Furthermore, no adverse 379D-related effects were observed in 0.1% and 1% groups. Feed efficiency was higher in the 379D-treated groups than in the control group. In conclusion, 379D is expected to be used as a safe alternative to antibiotics in a feed supplement and will improve feed efficiency in broiler chickens.
        4,000원
        482.
        2015.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We study the evolution of the energy spectrum of cosmic-ray electrons accelerated at spherically expanding shocks with low Mach numbers and the ensuing spectral signatures imprinted in radio synchrotron emission. Time-dependent simulations of diffusive shock acceleration (DSA) of electrons in the test-particle limit have been performed for spherical shocks with parameters relevant for typical shocks in the intracluster medium. The electron and radiation spectra at the shock location can be described properly by the test-particle DSA predictions with instantaneous shock parameters. However, the volume integrated spectra of both electrons and radiation deviate significantly from the test-particle power-laws, because the shock compression ratio and the flux of injected electrons at the shock gradually decrease as the shock slows down in time. So one needs to be cautious about interpreting observed radio spectra of evolving shocks based on simple DSA models in the test-particle regime.
        4,300원
        483.
        2014.12 구독 인증기관 무료, 개인회원 유료
        Recombinant thymosin β4 (rTβ4) has been reported to migrate and promote vascularization, wound-healing, and hair growth in a mouse hindlimb ischemia model of peripheral vascular disease. C57BL/6 mice (11-weeks-old) were anesthetized and an ischemic model was made by cutting the right aorta femoralis. The ischemic group was intraperitoneally administered with saline (300 μL/mouse) and the muscular administration group received rTβ4 (150 μg in 300 μL of saline) or rTβ4 (150 μg in 300 μL saline) to the abdominal cavity at 3-day intervals for 21 days. Myoatrophy of the ischemic group was observed compared to the normal control group. Generation of adjacent vessels was carried out in the rTβ4 administration group compared to the ischemic group. The biopsy results showed significant fibrosis around the muscular undersurface and perimysium in the musculus quadriceps femoris of the ischemic group, whereas partial fibrosis was observed in the perimysium and endomysium in the rTβ4 administration group. Immunostaining indicated that expression levels of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor-1 (VEGF-1), and endothelial nitric oxide synthase (eNOS) in the rTβ4 group were higher than those of the ischemic group. Western blotting showed that expression levels of HIF-1α, VEGF-1, and eNOS in the rTβ4 group were higher than those of the ischemic group. In conclusion, rTβ4 increases expression levels of HIF-1α, VEGF-1, and eNOS, resulting in angiogenesis.
        4,000원
        484.
        2014.12 구독 인증기관 무료, 개인회원 유료
        very important also for future generations in managing and inheriting CPR. A study was conducted on the CPR case of the village fishery managed by the Jongdal-ri Fishing Village Cooperative of Jeju Special Self-governing Province. The eight principles presented by Ostrom (1990) as the designed principles of sustainable CPR, that is to say, Clearly defined boundaries, Congruence between appropriation and provision rules and local conditions, Collective-choice arrangements, Monitoring, Graduated sanctions, Conflict-resolution mechanisms, Minimal recognition of rights to organize, and Nested enterprises, were analyzed. It was confirmed that the object case, Jongdal-ri Fishing Village Cooperative was managed based on these principles. Autonomous management rules are established by each fishing village cooperative community to fit their respective characteristics. Besides mere establishment of the rules, these rules should be preferentially be put into practice. The Jongdal-ri Fishing Village Cooperative successfully put them into practice, and was designated as the most superior fishing village cooperative community successively for three years. Collection was prohibited during a closed season for preservation of resources, and those of which the body length was shorter than that specified in the rules were not caught. That is to say, communities can sustainably manage CPR by complying with the conditions to be sustainable as well as following and putting in practice the rules, providing a CPR management system for future generations.
        4,600원
        485.
        2014.11 구독 인증기관·개인회원 무료
        Twenty Inter simple sequence repeat (ISSR) and 30 SSR primers were used to assess genetic diversity of 64 Agaricus strains including 45 A. bisporus strains and other 19 Agaricus spp. Of them, four ISSR primers, (GA)₈T, (AG)₈YC, (GA)₈C and (CTC)₆and seven SSR markers produced PCR polymorphic bands between the Agaricus species or within A. bisporus strains. PCR polymorphic bands were inputted for UPGMA cluster analysis. Forty five strains of A. bisporus are genetically clustered into 6 groups, showing coefficient similarity from 0.75 to 0.9 among them. The varieties, Saea, saedo, Saejeong and Saeyeon that have recently been developed in Korea were involved in the same group with closely genetic relationship of coefficient similarity over 0.96, whereas, other strains were genetically related to A. bisporus strains that were introduced from USA, Eroupe and Chinese.
        489.
        2014.10 구독 인증기관·개인회원 무료
        Methyl Bromide (MB) has been regulated by montreal protocol due to ozone depletion since 1992, and there is a need to develop MB alternative fumigation methods. To find out the efficacies and tolerance in developmental stages of citrus mealybugs (Planococcus citri) which frequently infested in imported pineapples, phosphine(PH3) gas was tested in different exposure times (2~24 hr) and concentrations (0.1∼2g/m3) in small desiccators at 8℃. Based on Lethal 99% concentration × time products (LCTP 99%) of PH3 gas to target developmental insect, 2g/m3 PH3 was applied for 24 hr in 300 m3 fumigation facility, which was designed in well sealed and evacuation system (5 air exchange/min). We monitored PH3 gas in fumigation facility to confirm CTP and checked PH3 gas in atmospheres in air ventiliation process after fumigations to make quarantine guideline and protocol for worker safety as well as efficacy to target pest.
        490.
        2014.09 구독 인증기관 무료, 개인회원 유료
        Porphyromonas gingivalis is one of the most important periodontal pathogens and has been to known to invade various types of cells, including endothelial cells. The present study investigated the mechanisms involved in the internalization of P. gingivalis in human umbilical vein endothelial cells (HUVEC). P. gingivalis internalization was reduced by clathrin and lipid raft inhibitors, as well as a siRNA knockdown of caveolin-1, a principal molecule of lipid raft-related caveolae. The internalization was also reduced by perturbation of actin rearrangement, while microtubule polymerization was not required. Furthermore, we found that Src kinases are critical for the internalization of P. gingivalis into HUVEC, while neither Rho family GTPases nor phosphatidylinositol 3-kinase are required. Taken together, this study indicated that P. gingivalis internalization into endothelial cells involves clathrin and lipid rafts and requires actin rearrangement associated with Src kinase activation
        4,000원
        491.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The recent theory in L2 motivation has proposed viewing motivation as possible selves such as ideal L2 self, ought-to L2 self, and L2 learning experiences to complement the limitation of traditional socio-educational model. The purpose of the study was to test the traditional integrativeness and L2 motivational self system in Korean EFL college contexts and how those motivations have developed over time through a cross-sectional study. A total of five hundred fifty five college students taking English as elective in Korea completed the motivation questionnaires. The results showed that both traditional integrative motivations and L2 motivational self system have increased positively over time at college. The post-hoc test revealed that the senior students developed significantly higher motivations than the freshmen in integrative orientation, attitudes towards learning English, and criterion measures. L2 motivational self system such as ideal L2 self, ought-to L2 self, and L2 learning experiences better predicted motivated behaviors than integrative motivations even though both had significant correlations. Theoretic discussions were made for L2 motivations.
        6,000원
        492.
        2014.07 구독 인증기관 무료, 개인회원 유료
        The luxury consumption has been pertinent to those aged around forties to fifties in the upper class. Recently, luxury product market became wide and is varying in age segments. Young consumers’ luxury consumption shows a rapid growth worldwide. Despite the global financial crisis, advanced information technology and globalized marketing strategies accelerate luxury consumption rate in vast. This phenomenon of luxury consumption is critically relevant to consumer social psychology. While people have various relationships with others in their own societies, they carry out impression management for themselves. Consumers try to identify themselves with goods, services, and images of brands or products. More importantly, congruency between their ideal images of themselves and consuming objects plays an important role in luxury consumption in recent years.
        4,000원
        493.
        2014.07 구독 인증기관·개인회원 무료
        Steel manufacturers in the Korean steel reinforcement market are facing increasing competition. Construction businesses are in a recession because demands have decreased, too many facilities have been built, and more imported materials are coming from Japan and China. Korean steel manufacturers focus on domestic sales as a result of these difficulties in the business environment. To overcome these difficulties, manufacturers must find strategies for producing high value products, minimizing distribution expenses, and reducing costs. However, such temporary expedients are insufficient. Accordingly, our study investigating steel manufacturer salespersons and agents that purchase supplies uncovered suggestions for remaining competitive. First, companies must outdo their competitors by offering more competitive prices. Second, they must be ahead of their competitors in announcing their prices. Companies can present their expected selling prices by analyzing their manufacturing costs, future market unit costs, and distribution unit costs of the present market. If they select prices for products they will sell in the next month, the data indicate that they can still expect to make profits. The lowest selling price is calculated by analyzing the manufacturing costs. By setting prices more rapidly than competitors, manufacturers should increase their market share by increasing sales volume.
        494.
        2014.07 구독 인증기관·개인회원 무료
        Entrepreneurship and marketing are two disciplines whose paths have intersected frequently, because the underlying orientation of each relates to markets and customer needs (Hills and LaForge, 1992). The most common argument surrounding this relationship has been that entrepreneurs do not follow the mainstream approach taken by large corporations when performing marketing functions. Consequently, many researchers have attempted to better understand how marketing is performed differently by entrepreneurs. Interestingly, however, extant research has tended to overlook the sui generis relationship between the entrepreneur and his firm, and the impact that such relationship potentially has on both the entrepreneur and his firm/brand.The missing link in entrepreneurial branding, we believe, lies in further understanding the dynamic that exists between the entrepreneur’s roles and his firm’s growth. Our thesis is that the entrepreneur assumes different roles in order to develop and grow his firm/brand and a newly created social structure, and eventually matures into a sense of belonging and commitment to his firm/brand that potentially attracts and retains all the other stakeholders associated with the firm/brand. This may be regarded as an identity construction process which is triggered by the entrepreneur and permeates into his firm/brand. In their cross-disciplinary exploration of entrepreneurship research, Ireland and Webb (2007) identified identity construction as one of the three broad concepts around which multilevel entrepreneurship theory can develop.Qualitative data were collected through a total of 25 in-depth semi-structured interviews with entrepreneurs from the U.K., Guatemala and Colombia. Informed Grounded Theory by Thornberg (2012) was used as a data analysis approach, permitting an empirical understanding of entrepreneurial branding illuminated by extant literature on branding, entrepreneurship and identity. Data analysis revealed that entrepreneurs whose businesses are growing are involved in a variety of actions that compel them to embrace three different roles. The first role, identified as the Entrepreneur Strategist, encompasses the triggering elements through which the entrepreneur creates the foundations and key purposes of his firm. The second role, identified as the Entrepreneur Sense-giver, captures the actions that the entrepreneur undertakes to embed his central beliefs, values and personal assumptions through his daily experiences with his employees in the firm. The third role, identified as the Entrepreneur Developer, captures the various actions that the entrepreneur embraces to permeate his firm’s and brand’s essence to the outside world, including the customers. Our study also supports the notion that the identity of an entrepreneur is a co-creation of an individual identity and a social identity. Our argument implicitly bridges the two traditionally disconnected perspectives of Identity Theory and Social Identity Theory through the entrepreneurship process. More specifically, the three roles that entrepreneurs potentially need to embrace in order to grow their firm/brand in the market are embedded within a dynamic process in which the entrepreneur’s personal identity is co-created alongside his firm’s and brand’s social identity. A successful entrepreneur of each entrepreneurial firm should eventually permeate the entrepreneurial brand essence, a distinct blend of his personal identity and his firm’s and brand’s social identity, into the world.
        495.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 방울토마토의 MA 저장시 저장기간 연장과 품질 유지를 위한 비천공 breathable 필름 종류를 구명하고자 진행되었다. 강원도에 위치한 플라스틱 하우스에서 수경재배한 토마토를 담적색기에 수확하여 5oC, 11oC, 그리고 24oC에서 산소투과도가 각기 다른 비천공 breathable 필름(10,000; 20,000; 40,000; 60,000; 80,000; 100,000 cc/m2.day.atm)과 천공필름으로 포장하여 저장하였다. 저장 중 생체중 감소율은 세가지 온도 모두에서 모든 비천공 breathable 필름처리구에서는 0.6%미만이었으나, 천공필름은 5oC는 2.93%, 11oC는 13.29%, 그리고 24oC에서는 27.24%에 달하였다. 포장내 이산화탄소와 산소 농도를 볼 때 5oC와 11oC에서 20,000 cc 필름, 24oC에서 40,000 cc 필름이 MA 조건에 근접한 수치를 보였다. 에틸렌 농도는 산소투과도가 가장 낮은 10,000 cc에서 모든 온도에서 가장 높았다. 저장 중 외관상 품질과 최종일에 측정한 경도와 당도는 5oC와 11oC의 20,000 cc 필름, 24oC의 40,000 cc 필름이 높은 수치를 나타내었다. 그러나 산도와 비타민 C 함량은 필름처리에 대한 일정한 경향을 보이지 않았다. 이상의 결과로 보았을 때, MA 저장시 포장내 대기조성과 저장 종료일의 과실 품질 등을 비교한 결과 방울토마토는 5oC와 11oC에서 20,000 cc 필름, 24oC에서는 40,000 cc 필름이 적합하였다.
        4,000원
        496.
        2014.06 구독 인증기관 무료, 개인회원 유료
        Renal dysplasia is a developmental disorder of the renal parenchyma involving anomalous differentiation. It is characterized by persistent metanephric ducts surrounded by primitive mesenchyme, fetal or immature glomeruli, fetal or immature tubules, interstitial fibrosis, and dysontogenic metaplasia involving tissues such as cartilage. Renal dysplasia has been rarely reported in rats. Here, we observed a small left kidney in a rat used in a short-term repeat toxicity study. The rat showed no clinical signs throughout the study. All parameters, including those reflecting kidney functions, were normal upon hematological examination and urinalysis. Grossly, the kidney was small (5 × 8 mm) and its surface appeared normal. Histological examination revealed that the cortex and medulla were poorly demarcated and contained immature/atrophic glomeruli, immature renal tubules, and mesenchymal cells. The cortex contained immature glomeruli, atrophic glomeruli with cystic dilatation of Bowman’s capsular space, and some atypical tubules. Primitive metanephric tubules in the medulla were larger in diameter than normal collecting ducts, lined by a tall columnar epithelium with pale cytoplasm and basal nucleus, and surrounded by loose mesenchymal cells. Occasional tubules contained pale eosinophilic homogenous material in the lumen. Thus, this was diagnosed as a case of renal dysplasia on the basis of histologic features and is the first reported case of renal dysplasia in Sprague Dawley rats.
        3,000원
        497.
        2014.06 구독 인증기관 무료, 개인회원 유료
        The current study was conducted to evaluate the biocompatibility of α-1,3 galactosyltransferase knockout pig bone graft in a rat calvarial defect model. Porcine cancellous bones were harvested from general and alpha-gal KO pigs and washed with 70% ethanol solution and normal saline. Bone pieces of the alpha-gal KO pig underwent a chemical treatment process to delipidize and deproteinize the bone. Bone graft particles were freeze-dried and stored at −70°C until use. Each bone graft was implanted into the rat calvarial defect in a fresh general pig, fresh transgenic pig, and chemical-treated pig bone group. There was no systemic adverse effect on hematology or necropsy findings in all groups at 1 week and 4 weeks. In the microcomputed tomography analysis, bone volume increased significantly in the chemical-treated transgenic pig bone group, whereas bone mineral density decreased significantly in the fresh general pig bone group compared with other groups. Histological evaluation showed cellular infiltration located at the margin of the bone graft particles, especially in the fresh general pig bone group. These results indicate that fresh general pig bone can elicit a greater local inflammatory response than fresh transgenic pig bone. Further, chemical-treated transgenic pig bone graft was less immunogenic than fresh bone graft. In conclusion, transgenic pig bone is a more biocompatible graft material. In addition, chemical treatment can reduce bone graft immunogenicity by delipidizing and deproteinizing bone.
        4,000원
        498.
        2014.06 구독 인증기관 무료, 개인회원 유료
        The specific genetic modification in porcine somatic cells by gene targeting has been very difficult because of low efficiency of homologous recombination. To improve gene targeting, we designed three kinds of knock-out vectors with α1,3-galactosyltransferase gene (α1,3-GT gene), DT-A/pGT5’/neo/pGT3’, DT-A/NLS/pGT5’/neo/pGT3’ and pGT5’/neo/ pGT3’/NLS. The knock-out vectors consisted of a 4.8-kb fragment as the 5’ recombination arm (pGT5’) and a 1.9-kb fragment as the 3’ recombination arm (pGT3’). We used the neomycin resistance gene (neo) as a positive selectable marker and the diphtheria toxin A (DT-A) gene as a negative selectable marker. These vectors have a neo gene insertion in exon 9 for inactivation of α1,3-GT locus. DT-A/pGT5’/neo/pGT3’ vector contain only positive-nega-tive selection marker with conventional targeting vector. DT-A/NLS/pGT5’/neo/pGT3’ vector contain positive-negative selection marker and NLS sequences in upstream of 5’ recombination arm which enhances nuclear transport of foreign DNA into bovine somatic cells. pGT5’/neo/pGT3’/NLS vector contain only positive selection marker and NLS sequence in downstream of 3’ recombination arm, not contain negative selectable marker. For transfection, linearzed vectors were introduced into porcine ear fibroblasts by electroporation. After 48 hours, the transfected cells were selected with 300 μg/ml G418 during 12 day. The G418-resistant colonies were picked, of which 5 colonies were positive for α1,3-GT gene disruption in 3´ PCR and southern blot screening. Three knock-out somatic cells were obtained from DT-A/NLS/ pGT5’/neo/pGT3’ knock-out vector. Thus, these data indicate that gene targeting vector using nuclear localization signal and negative selection marker improve targeting efficiency in porcine somatic cells.
        4,000원
        499.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this research is to initiate discussion to simplify existing tools and methods for managing projects which make project management a harder job to perform and a tougher task to handle. Additionally, summarizing the definitions of “project” that have been found from reviewing the relevant literature, it deliberates on revising the duties and responsibilities of project manager and proposes performance expectancy triangle explaining a relationship among accountability, responsibility and authority – the Tri-butes. It sheds light on several factors critical to the success of projects. Finally, we propose a function indicating that customer demands or desires greatly affect project complexity.
        4,000원
        500.
        2014.06 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to develop the growth prediction model that can predict growth and development information influencing on the production of citrus fruits. The growth model was developed to predict the floralleaf ratio, number of fruit sets, fruit width, and overweight fruits depending on the main period of growth and development by considering the weather factors because the fruit production is influenced by weather depending on the growth and development period. To predict the outdoor-grown citrus fruit production, the investigation result for the standard farms is used as the basic data; in this study, we also understood that the influence of weather factors on the citrus fruit production based on the data from 2004 to 2013 of the outdoor-grown citrus fruit observation report in which the standard farms were targeted by the Agricultural Research Service and suggested the growth and development information prediction model with the weather information as an independent variable to build the observation model. The growth and development model for outdoor-grown citrus fruits was assumed by using the Ordinary Least Square method (OLS), and the developed growth prediction model can make a prediction in advance with the weather factors prior to the observation investigation for the citrus fruit production. To predict the growth and development information of the production of citrus fruits having a great ripple effect as a representative crop in Jeju agriculture, the prediction result regarding the production applying the weather factors depending on growth and development period could be applied usefully.
        4,200원