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        검색결과 1,279

        441.
        2016.10 구독 인증기관·개인회원 무료
        Oocytes from small antral follicles (< 3 mm in diameter; SAFO) show lower developmental competence compared to those from medium antral follicles (3-8 mm in diameter; MAFO) in pigs. This study was designed to evaluate the effect of various macromolecules such as fetal bovine serum (FBS), porcine follicular fluid (PFF), bovine serum albumin (BSA) and polyvinyl alcohol (PVA) in in vitro growth (IVG) medium on oocyte growth, maturation, and embryonic development after parthenogenesis (PA). The base medium for IVG was α-MEM supplemented with dibutyryl cyclic AMP, pyruvate, kanamycin, hormone. This medium was further supplemented with 10% FBS, 10% PFF, 0.4% BSA, or 0.1% PVA. The in vitro maturation (IVM) medium was medium-199 supplemented with 10% PFF, cysteine, pyruvate, epidermal growth factor, kanamycin, insulin, and hormones. SAFO were cultured for 2 days for IVG and then cultured for 44 h for IVM. After IVG, the mean diameter of SAFO treated with FBS, PVA, and no IVG-MAFO (114.1, 113.0, and 114.8 μm, respectively) was significantly larger (P<0.01) than that of no IVG-SAF (111.8 μm). Oocyte diameter after IVM was greater (P<0.01) in SAFO treated with FBS, BSA and PVA (112.8, 112.9 and 112.6 μm, respectively) than other groups (110.4, 109.6, and 109.8 μm for no IVG-MAFO, no IVG-SAFO and PFF, respectively). Intraoocyte GSH content was not influenced by the macromolecules in IVG medium (0.92, 0.93, 1.05, and 1.12 pixels/oocyte for FBS, PFF, BSA and PVA, respectively). The proportion of oocytes reached the metaphase II stage was higher in PFF (73.6%) than in BSA (43.5%) and PVA (53.7%) but not different from that of FBS treatment (61.5%). The cumulus expansion score of oocytes after IVG was significantly influenced (P<0.01) by the macromolecules (2.94, 2.24, 1.84, and 1.38 for PFF, FBS, PVA, and BSA treatments, respectively). Blastocyst formation of PA oocytes that were treated with FBS (51.8%), PFF (50.4%), and PVA (45.2%) during IVG was higher (P<0.05) than that of BSA-treated oocytes (20.6%) but was not significantly different from that (54.8%) of no IVG-MAFO oocytes. Our results demonstrated that growth, maturation, and embryonic development of SAFO are greatly influenced by macromolecules in IVG medium and that PFF or FBS can be replaced with a chemically defined synthetic macromolecule PVA.
        442.
        2016.10 구독 인증기관·개인회원 무료
        In vitro production of mammalian embryos has been achieved with the oocytes derived from middle-size follicles (MF, mainly 3-6 mm in diameter) in many species including domestic animals. In the ovaries, however, there are more small-size follicles with less than 3 mm in diameter (SF). If we can develop an efficient system to produce embryos in vitro from the oocytes from SF. In this presentation, I would like to review about embryo production in vitro from the oocytes derived from SF. As well as the diameter of oocytes, the number of cumulus cells surrounding the oocyte derived from SF is significantly smaller those of oocytes from MF. The comparative analysis in electrophoresis about secretions of cumulus-oocyte complexes derived from SF and MF demonstrated a significant difference in the proteins with a molecular weight. Proteins secreted from cumulus cells, vascular endothelial growth factor (VEGF), are 34- to 42-kDa proteins, including seven family members. The molecular weight of VEGF was similar with the secretion we observed. Supplementation of medium for in vitro maturation with VEGF significantly improved the oocytes competence not only to complete the meiosis in vitro but also to develop to the blastocyst stage following parthenogenetical activation. Removing cumulus cells 20 h after the start of culture for in vitro maturation also significantly improved the competence of oocytes derived from SF to achieve the meiosis. A combination of these new techniques may improve more the meiotic and developmental competences.
        443.
        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.
        444.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to compare the appearance rate of vaginal cytology during estrous cycle in small pet bitches. A characteristic features of vaginal cytology during the estrous cycle were the high proportion of superficial cell in proestrus, anuclear cell in estrus, small intermediate cell in diestrus, and small intermediate cell in anestrus, respectively. There were no statistically significant differences of appearance rate of vaginal cytology among small pet bitches in the each phase of estrous cycle. These results indicated that the vaginal cytology was useful method for estimating estrous cycle and optimal breeding time in small pet bitches.
        4,000원
        445.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In freshwater ecosystems, the types of fish parasites are diverse and routes of infection are complicated because they maintain the life cycle in a variety of host animals, The present study investigated the infestation characteristics of parasites occurring in abdominal cavity of Zacco platypus in Seom River from February to October 2007. At the same time, four streams (Gam Stream, Daepo Stream, Yangsan Stream, and Yulha Stream) were also surveyed for the reference of fish infection. Aquatic insects and shellfish predominated benthic macroinvertebrate assemblages by 90.4% and 7.7% of relative abundance, respectively. Aquatic insects were composed mostly of Ephemeroptera (46.8%) and Trichoptera (29.8%), and shellfish was Gastropods. Freshwater fish was most abundant Cyprinid and Z. platypus by 85.7% and 48.8%, respectively. Among waterfowl, Anas poecilorhyncha and Egretta garzetta were dominant in August. Fish parasites observed in the abdominal cavity of Z. platypus was classified as Ligula intestinalis, belonging to Phylum Platyhelminthes Cestoda Pseudophyllidae. L. intestinalis was observed from Z. platypus in October, as the number of one individual in the Seom River and fifteen individuals in the Yangsan Stream. Infection rate of plerocercoid ranged 1.4~15.8%. We discussed the relationship between the life cycle of the parasite and the host, and hope our results to be useful for understanding the ecology of the fish abdominal parasites in Korean river ecosystem.
        4,500원
        446.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To promote the efficiency of production process of small and medium sized company, government conducts production information business that collects and analyzes information of production field automatically and helps process' controlling and supervising by supporting costs of purchase, installment, etc. of hard-software and network related to middle and small sized company intending e-Manufacturing of production field with computer and information & communication network. As a result, the number of middle and small sized companies that introduce and manage production information system is increased. Therefore, the purposes of this research are to arrange contents of production information system introduced to solve current problems of middle and small sized companies and analyze effects of small and middle sized companies' introduction through example companies.
        4,000원
        447.
        2016.09 구독 인증기관 무료, 개인회원 유료
        본 연구에서는, F4-ZnPc 광활성층 기반의 저분자 유기태양전지의 성능을 최적화 하기 위해서 다 양한 조건의 홀이동층과 전자이동층을 조합하는 연구를 진행하였다. BF-DPB 호스트 유기물에 C60F36 또 는 NDP9 도펀트를 도핑한 조합을 홀이동층으로 사용하였고, 전자이동층으로는 W2(hpp)4가 도핑된 C60 또는 순수 C60/Bphen 물질을 사용하였다. 다양한 홀/전자이동층의 조합은 유기태양전지의 단락전류밀도와 fill factor, 효율에 영향을 끼치는 것을 관찰할 수 있었다.
        4,000원
        448.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 남해도 일대를 흐르는 소하천들을 대상으로 2014년 6월부터 10월까지 조사하여 다음과 같은 결과를 얻었다. 남해도의 23개 소하천의 31개 지점에서 채집된 어류는 모두 13과 30속 38종으로 나타났다. 이 중 잉어과 (Cyprinidae), 망둑어과(Gobiidae) 어류가 각각 11종(28.9%)으로 다른 분류군에 비하여 높은 비율을 차지하였으며, 미꾸리과(Cobitidae) 어류가 4종(10.5%)이 출현하였다. 남해도에서 채집된 전체 어류 중 참갈겨니(Zacco koreanus)의 상대풍부도가 30.3%(1,089개체)로 가장 높은 비율을 보였으며, 한국고유종은 참갈겨니, 긴몰개, 쉬리, 눈동자개, 남방종 개, 왕종개, 미유기, 자가사리 등 8종(33.8%)이었고, 외래도입종으로 큰입배스(Micropterus salmoides)가 출현하였다. 종다양도 지수, 균등도 지수 및 종풍부도 지수로 보면 S7에서 비교적 안정적인 어류 군집을 형성하고 있었다. 조사된 남해도 소하천들은 하폭, 수심, 하상 구성물질, 하천식생 및 주변의 토지이용도에 따라 산지형, 산지-평지형, 평지형 소하천의 3가지 유형으로 구분되었다. 종별 개체수 자료를 사용하여 요인분석을 실시한 결과, 조사지점은 인간의 인위적 영향 및 토지이용도에 따라 3개의 집단으로 구분되었다. 남해도 소하천의 어류 군집구조는 일차적으로 하상의 종적 환경 변화에 의하여 영향을 받고 있으며, 일부 소하천에서는 토지이용도에 따른 서식지 변화에 의하여 어류 군집구조에 영향을 주는 것으로 나타났다.
        4,800원
        449.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is aimed to design the mechanical gascyclone precipitator with an outstanding collection efficiency as one of ways to reduce exhaust gas of small-scale vessels. It estimated fine particles generated from diesel engines which has become one of the biggest environmental issues currently. Specifically, it quantitatively analyzed the flowing process from the cyclone gas exit; a duct via part to the collecting part of Cylindrical lower using DPIV (Digital Particle Image Velocimetry). Since the gas inlet height part became wider the previous theoretical dimensions, internal fluid characteristics of cyclone where the speed of internal swirl had been slow were investigated by temporary streamline of fine particles at 14-20 ㎛. The results showed that collecting efficiency was three times higher than the conical type utilized previously. In addition, this study supplemented imprecision problems from the previous theoretical equation and CFD interpretation with an experimental method. It also provided a basic data to design the cyclone precipitator by size of diesel engines for vessels.
        4,000원
        450.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Yield-per-recruit (YPR) analysis is used to provide management guidance for the efficient use of a fish cohort. However, the individual fish price per unit weight of small yellow croaker (Larimichthys polyactis) or hairtail (Trichiurus lepturus) increases dramatically by size in Korea. Therefore, age-based production value-per-recruit (PPR) analysis has recently been developed (Zhang et al., 2014). Since age determination requires a substantial amount of money and time and it is even impossible for some fish species, it is difficult to obtain age information to apply the age-based PPR model. Thus, we attempted to develop an alternative method, which uses length data rather than age information, called the length-based PPR analysis. The results revealed that length-based PPR analysis was much more conservative for stock management than the YPR analysis. Furthermore, the PPR analysis was more economically beneficial than the YPR analysis, which can prevent the fish stock from the economic overfishing. In conclusion, the length-based PPR analysis could be a proper approach for stock assessment in the case that the individual fish price per unit weight increases dramatically by size, and this analysis is useful to obtain vital management parameters under data-deficient situation when traditional stock assessment methods are not applicable.
        4,300원
        452.
        2016.07 구독 인증기관·개인회원 무료
        The value created by supply chain management (SCM) practices means managers today are even more interested in these initiatives, this is especially true in emerging markets where they can have a profound impact. This research examines several critical SCM initiatives (strategic supplier partnerships, information quality, and proactive logistics practices), and their impact on supply chain flexibility, and ultimately organizational performance for small scale (fewer than 100 employees) manufacturing firms in India. These constructs are especially important for India because it has been suggested that they have high logistics costs as a result of insufficient infrastructure (e.g., power grid) and various labor-related issues. Under the Extended Resource Based View of the firm (Mathews, 2003) managers realize that capitalizing on supplier capabilities can improve the firm’s own responsiveness and overall performance. Therefore we examined strategic supplier partnerships (the long-term cooperative exchanges with critical suppliers) and proactive logistics practices (the interactions specifically with logistics providers regarding planning and joint problem solving), along with information quality (including accuracy, adequacy, timeliness, and credibility of information being exchanged) (Monczka et al., 1998). Other constructs include supply chain flexibility (the ability of the firm to respond to any change concerning its trading partners) and organizational performance (capturing productivity, efficiency, market share, and profit level) (Yamin et al., 1999; Tan et al., 1998). Validated scales developed by Li (2002) and Tan et al. (1998) were used and firm owners were targeted from a list of Coimbatore’s (a city in India) small scale manufacturers covering a wide-range of industries. The result was 75 completed surveys (a 94% response rate) which we evaluated using partial least squares (PLS) path modeling as appropriate for our sample size. The findings indicate that improving strategic supplier partnerships and information quality enables the firm to achieve a more flexible supply chain and ultimately better organizational performance. This research improves our understanding of critical considerations
        453.
        2016.07 구독 인증기관 무료, 개인회원 유료
        This paper develops a conceptual model relating motivation, involvement, and changes to travel style to the selection of destinations and choice of events amongst non-professional participants involved in small-scale sporting events. A longitudinal comparison of t
        4,800원
        454.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experimental study was conducted to identify the correlation between speaker design factors and T/S parameters. For experiments to be conducted in the study, the sample speakers modified the damper, sub-cone, and mass of diaphragm of woofer speaker for vehicles were made to find characteristics of mechanical factors of speaker and non-linear factors; and the sound pressure characteristics were investigated. The correlation between design factors and T/S parameters showed that the strength of suspension system and the mass of motor part increased with the increase of mass of cone paper; and the force factor and resonance frequency tended to exhibit different behaviors according to the changes of damper.
        4,000원
        455.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Piloti-type building is one of typical vertical atypical buildings. These buildings can fail by weak-story or flexible-story mechanism on the first story. They should be designed by taking into account the special seismic load, but those less than six stories are not required to confirm the seismic performance from structural engineers in Korea. For this reason, small-size pilloti-type RC buildings need to be checked for seismic performance. Based on this background, this study performed nonlinear dynamic analysis using the PERFORM-3D for small-size pilloti-type RC buildings and assessed their seismic performance. Examples are two through four story buildings with and without walls in the first story. The walls and columns in the first story satisfied the target performance in the basic of flexural behavior due to quite a large size and reinforcement. However, wall shear demands exceed shear strength in some buildings. When designed for KBC2009, wall shear strength exceed shear demand in some buildings, but still does not in others. Consequently, wall shear must be carefully checked in both existing and new small-size pilloti-type RC buildings.
        4,000원
        456.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to observe the wind load characteristics around two-dimensional rotor blade of small wind turbine under high wind speed. The CFD analysis on the blade shape of NACA-4418 is performed to understand the wind load(i.e., drag and lift coefficient). In the results, the drag and lift coefficient were estimated to be 0.013, 0.44, respectively, at the wind speed 35m/s(wind speed at the height of wind tower, z=70m) and angle of attack 3°. By using the lift, drag coefficient and the appropriate assumption of the blade length, the number of blade and the tip speed ratio(TSR), the proper blade shape was obtained. On the base of this basic study, various conditions for Reynolds number and aerodynamic analysis including angle of attack according to parametric test need to study more in the future. Also assessment for the blade need to study safety on wind pressure coefficient and distribution according to wind characteristics.
        4,000원
        457.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study organizes not only the middle-long term developing plan of safety health education to put emphasis on a manufacturing industry, but also the developing plan of activating the domestic safety health education. On the basis of this study, current safety health education can be developed. To achieve a goal of implementing domestic safety health education, this study is carried out more deeply as follows.
        4,000원
        458.
        2016.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Small-size buildings are not designed by professional structural engineers in Korea. Therefore, their seismic performance can not be exactly estimated because their member sizes and reinforcement may be over- or under-designed. A prescriptive design criteria for the small-size buildings exists, but it also provides over-designed structural members since structural analysis is not incorporated, so it is necessary to revise the prescriptive criteria. The goal of this study was to provide an information for the revision, which is seismic performance and capability of small-size reinforced concrete moment frame buildings. For the study, the state of existing small-size reinforce-concrete buildings such as member size and reinforcement was identified by investigating their structural drawings. Then, over-strength, ductility and response modification factor of the small-size reinforced concrete moment frame buildings were estimated by analytical approach along with seismic performance check. The result showed that they possess moderate over-strength and ductility, and may use slightly increased response modification factor.
        4,000원