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        검색결과 9,514

        5263.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to comparatively analyze the active stability of shoulder joints according to the frequency of overhead motions, such as serving and spiking, engaged in by female professional volleyball athletes who play different positions, and to provide the results as the basic data for developing exercise programs to prevent shoulder joint injuries. The subjects of this study were 50 Korean female professional volleyball players and positions were as follows: left and right attackers, centers, setters, and liberos. The external rotation and internal rotation muscle strength and muscle strength ratios of the dominant and non-dominant arms of all subjects were measured using Biodex. The results of this study are as follows: Frist, no significant differences were found in the internal and external rotation muscle strength of the dominant and non-dominant arms between positions. Second, for the shoulder joint muscle strength ratio of the dominant arm, by position, the setter showed significantly greater stability compared to the other positions. Third, for the shoulder joint muscle strength ratio of the non-dominant arm, by position, no significant difference in stability between positions was found. Fourth, it was found that the dominant arm had significantly greater instability of the shoulder joint than the non-dominant arm for attackers and centers, but no significant difference was found for setters and liberos. This study comparatively analyzed the muscle strength ratios of the external/internal rotations and dominant/non-dominant arms, which can determine the stability of the shoulder joints between female professional volleyball playing positions that engage in jumps and spikes using only the dominant hand and positions that do not.
        4,000원
        5264.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this case report, we investigated the effects of robot-assisted gait therapy in a chronic stroke patient using motor assessment and gait analysis. A patient who suffered from the right hemiparesis following the left corona radiata and basal ganglia infarction received 30 minutes of robot-assisted gait therapy, 3 times a week for 4 weeks. Outcome was measured using Motoricity index(MI), Fugl-Meyer assessment(FMA), modified motor assessment scale(MMAS), isometric torque, body tissue composition, 10-meter gait speed and gait analysis. After robot-assisted gait therapy, the patient showed improvement in motor functions measured by MI, FMA, MMAS, isometric torque, skeletal muscle mass, 10-meter gait speed. In gait analysis, cadence, single support time, double support time, step length, walking speed improvement in after robot-assisted gait therapy. The results of this study showed that robot-assisted gait therapy is considered to facilitate locomotor recovery of the chronic hemiparetic stroke patient.
        4,000원
        5265.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The protease produced by a Bacillus pumilus CN8 strain was purified by DEAE-Cellulose-52 ion exchange. It has a molecular weight of approximately 96,920 Dalton. In the present study, this protease showed strong activity over a broad range of pH (6.5-9.5) and temperature from 40℃ to 60℃, and the protease performed the maximal activity at pH 7.3 at 42℃. The effect of metal ions on protease activity showed that K+ could slightly increase the protease activity, and other ions such as Zn²+, Fe²+, Na+, Ca²+, Mg²+ had no significant activation or inhibition to the protease (P > 0.05), and the more important is that Cu²+, Mn²+, Sn²+, Cd²+ had a strong inhibitory effect on the protease activity.
        4,000원
        5266.
        2011.03 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to examine the effect of various discontinuous Percoll washing conditions on motile sperm recovery rate and motion kinematics. Frozen semen samples from 3 bulls (0.5 ml plastic straws, 6% glycerol in egg yolk-Tris-glycerol extender) were thawed in 37℃ water bath for 1 min. After thawing, the mixed semen samples were randomly allocated to 12 treatment groups. Briefly, the spermatozoa were centrifuged for three different time lengths (10, 20, and 30 min) at two gravities (300×g and 700×g) through two concentrations of discontinuous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll and 2 ml 90%: 2 ml 45% Percoll to remove extender, debris, and dead spermatozoa. Motile sperm recovery rate and motion kinematics were evaluated by computer assisted sperm analyzer using Makler counting chamber. Sperm motility (%) and motile sperm recovery rate showed similar pattern in all treatment groups. However, sperm motility (%) and motile sperm recovery rate were highest at 700×g for 30 min through a discontionous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll. There were no significant differences in motion kinematics after various Percoll washings. These results suggest that force of centrifugation, centrifugation time, and Percoll volume significantly affect motile sperm recovery rate.
        4,000원
        5267.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Endocrine disruptors bind to hormone receptors on sperm membrane, therefore spermatozoa are potentially a useful model for examining estrogenic activities of endocrine disruptors. The objective of this study was to compare the effects of two xenoestrogenic compounds [genistein (Gen) and 4-tert-octylphenol (OP)] to those of two steroids [estrogen (E2) and progesterone (P4)] on boar sperm % motility and motion kinematics of in vitro. Porcine spermatozoa were incubated with various concentrations (0.001~100 μM) of each chemical for 15 or 30 min, and then assessed % motility and sperm motion kinematics using computer assisted sperm analyzer (CASA). Each chemical decreased sperm % motility, and OP decreased VSL and VAP compared with untreated control(p<0.05). E2 stimulated the motion kinematic changes except VCL. Moreover, Gen had effects on VCL and VAP alterations after 30 min incubation. In summary, since all chemicals studied effectively altered sperm % motility and motion kinematics, it was concluded that porcine spermatozoa could be a useful model for in vitro screening of potential endocrine disruptors.
        4,000원
        5268.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate Korean high school students’ comprehension level and attitudes towards three different English accents: American-accented, Malaysian-accented, and Korean-accented English. The experiment was conducted with 340 female high school students in Gyeongsangnam-do. The data collection in this study consisted of the results of three listening comprehension tests and two survey questionnaires. The results show that speakers' various English accents affected the participants’ listening comprehension: The participants understood the American-accented and the Korean-accented English better than the Malaysian-accented English. The study also shows that there is no interaction between the English accents and the participants' L2 listening proficiency levels. In addition, the results indicate that the participants display more positive attitude toward American-accented English, followed by Malaysian-accented English, and finally Korean-accented English. This paper therefore suggests that Korean students need to be exposed to various English accents in order to become familiar with the concept of World Englishes.
        6,300원
        5269.
        2011.03 구독 인증기관 무료, 개인회원 유료
        The working mechanism of bisphosphonate on bone cells is unclear despite its powerful inhibitory activity on bone resorption. The differentiation and activation of osteoclasts are essential for bone resorption and are controlled by the stimulatory RANKL and inhibitory OPG molecules. Teeth exhibit a range of movement patterns during their eruption to establish their form and function, which inevitably accompanies peripheral bone resorption. Hence, the mandible, which contains the teeth during their eruption processes, is a good model for revealing the inhibitory mechanism of bisphosphonate upon bone resorption. In the present study, RANKL and OPG expression were examined immunohistochemically in the mandible of rats with developing teeth after alendronate administration (2.5 mg/kg). The preeruptive mandibular first molars at postnatal days 3 to 10 showed the developing stages from bell to crown. No morphological changes in tooth formation were observed after alendronate administration. The number of osteoclasts in the alveolar bone around the developing teeth decreased markedly at postnatal days 3, 7 and 10 compared with the control group. RANKL induced strong positive immunohistochemical reactions in the dental follicles and stromal cells around the mandibular first molar. In particular, many osteoclasts with strongly positive reactions to RANKL appeared above the developing mandibular first molars at postnatal days 3 and 10. Immunohistochemical reactions with RANKL after alendronate administration were weaker than the control groups. However, the immunohistochemical reactivity to OPG was stronger after alendronate administration, at postnatal days 3 and 10. These results suggest that alendronate may decrease bone resorption by regulating the RANKL/OPG pathway in the process of osteoclast formation, resulting in a delay in tooth eruption.
        4,000원
        5270.
        2011.03 구독 인증기관 무료, 개인회원 유료
        This study was designed to determine the effect of electric field strength, duration and fusion buffer in fusion parameters on the rate of membrane fusion between the somatic cell and cytoplast for Korean cattle (HanWoo) somatic cell nuclear transfer (SCNT) procedure. Following electrofusion, effect of 5 or 10 μM Ca2+-ionophore of activation treatment on subsequent development was also evaluated. Cell fusion rates were significantly increased from 23.1% at 20 V/mm to 59.7% at 26 V/mm and 52.9% at 27 V/mm (p<0.05). Due to higher cytoplasmic membrane rupture or cellular lysis, overall efficiency was decreased when the strength was increased to 30 V/mm (18.5%) and 40 V/mm (6.3%) and the fusion rate was also decreased when the strength was at 25 V/mm or below. The optimal duration of electric stimulation was significantly higher in 25 μs than 20 and 30 μs (18.5% versus 9.3% and 6.3%, respectively, p<0.05). Two nonelectrolyte fusion buffers, Zimmermann’s (0.28 M sucrose) and 0.28 M mannitol solution for cell fusion, were used for donor cell and ooplast fusion and the fusion rate was significantly higher in Zimmermann’s cell fusion buffer than in 0.28 M mannitol (91.1% versus 48.4%, respectively, p<0.05). The cleavage and blastocyst formation rates of SCNT bovine embryos activated by 5 μM Ca2+-ionophore was significantly higher than the rates of the embryos activated with 10 μM of Ca2+-ionophore (70.0% versus 42.9% and 22.5% versus 14.3%, respectively; p<0.05). This result is the reverse to that of parthenotes which shows significantly higher cleavage and blastocyst rates in 10 μM Ca2+-ionophore than 5 μM counterpart (65.6% versus 40.3% and 19.5% versus 9.7%, respectively; p<0.05). In conclusion, SCNT couplet fusion by single pulse of 26 V/mm for 25 μs in Zimmermann’s fusion buffer followed by artificial activation with 5 μM Ca2+-ionophore are suggested as optimal fusion and activation methods in Korean cattle SCNT protocol.
        4,000원
        5271.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The research on the role of working memory in L1 and L2 reading comprehension has provided valuable insight on domain-general mechanisms at work in both comprehension processes. The present paper explains a construct of working memory as a multicomponent model (Baddeley, 2007; Baddeley & Hitsch, 1974), reviews empirical studies that investigated the impact of working memory in L1 and L2 reading comprehension, introduces a newly adopted construct to the model of working memory, episodic buffer or long-term working memory (Erricson & Kintsch, 1995), and discusses the role of background knowledge in relation to working memory. The review of the studies showed that central executive, an attentional control system, is a significant predictor for not only L1 reading but also L2 reading comprehension. Phonological loop, a storage system, is significantly related to central executive. However, it is not a direct significant predictor for L1 and L2 reading comprehension; instead, it explains significant variances of vocabulary acquisition in the beginning stage of language acquisition, which is a direct significant predictor for reading comprehension. How high vs. low working memory groups make use of their cognitive resources in L1 and L2 reading when provided with additional background knowledge is further discussed.
        5,500원
        5272.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Somatic cell nuclear transfer (SCNT) is a useful tool for reproducing genetically identical animals or producing transgenic animals. Many reports have demonstrated that the efficiency of animal cloning by SCNT requires reprogramming of the somatic nucleus to a totipotent like-state. The SCNT-related reprogramming might mimic the natural reprogramming process that occurs during normal mammalian development. However, recent evidence indicates that the reprogramming event by SCNT is incomplete. In this study, the traditional SCNT procedure (TNT) was modified by injecting donor nuclei into recipient cytoplasm prior to the enucleation process to expose the donor nucleus before removing the karyoplast containing the chromosomes of the oocytes which might possess additional reprogramming factors, and this modified technique was named as reversing the usual order of SCNT (RONT). Other procedures including activation and in vitro culture were the same as TNT. Contrary to expectations, the rate of blastocyst development was not different significantly between RONT and TNT (8.6% and 7.9%, respectively). However, duration of micromanipulation performed by the same technician and equipments was remarkably reduced because the ruptured oocytes after nuclear injection were excluded from the enucleation process. This study suggests that RONT, a simplified SCNT protocol, shortens the duration of SCNT procedure and this less time-costing protocol may enable the researchers to perform murine SCNT easier.
        4,000원
        5273.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the influence of mesoporous carbons on the thermal insulation properties of epoxy/mesoporous carbon composites. The mesoporous carbon (CMK-3) was prepared by conventional templating method using SBA-15. The epoxy/mesoporous carbon composites were prepared by mixing the synthesized CMK-3 with diglycidylether of bisphenol A (DGEBA). As experimental results, the curing reactivities of the DGEBA/CMK-3 composites were found to decrease with the addition of the CMK-3. Also, the thermal conductivities of DGEBA/CMK-3 composites were found to decrease with increasing CMK-3 content. This could be interpreted in terms of the slow thermal diffusion rate resulting in pore volume existing in the gaps in the interfaces between the mesoporous carbon and the DGEBA matrix.
        3,000원
        5274.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbon fibers (ACFs) were prepared from cost effective commercial textiles through stabilization, carbonization, and subsequently activation by carbon dioxide. ACFs were characterized for surface area and pore size distribution by physical adsorption of nitrogen at 77 K. ACFs were also examined for various surface characteristics by scanning electron microscopy, Fourier transform infrared spectroscopy, and CHNO elemental analyzer. The prepared ACFs exhibited good surface textural properties with well developed micro porous structure. With improvement in physical strength, the commercial textile grade acrylic precursor based ACFs developed in this study may have great utility as cost effective adsorbents in environmental remediation applications.
        3,000원
        5276.
        2011.03 구독 인증기관 무료, 개인회원 유료
        To investigate the effect of carnosine on exhaustive exercise, swimming tests were conducted weekly with loads corresponding to 5% of body weight attached to the tails of mice, and the swimming time to exhaustion was measured. Eighty male ICR mice were divided into four groups, to which carnosine was administered at doses of 0 (control), 10, 50, and 250 mg/kg/day, respectively, for a period of four weeks. At the end of swimming exercise challenges, serum biochemistry, oxidative stress enzyme activity, and antioxidant enzyme activity in tissues were determined. Treatment with 250 mg/kg carnosine resulted in a significant increase in swimming times to exhaustion, compared to the control group in the first (P<0.01) and third week (P<0.05). Significantly lower serum lactate levels were observed after the swimming exercise in the carnosine-treated groups (10 and 250 mg/kg), compared with the control (P<0.01). Malondialdehyde levels in the liver (10 and 50 mg/kg carnosine treated groups) and skeletal muscle (250 mg/kg carnosine treated group) were significantly lower, compared with the control (P<0.05). Significantly lower protein carbonyl levels in skeletal muscle were observed in the 50 and 250 mg/kg carnosine treated groups, compared with the control (P<0.01). Superoxide dismutase and glutathione peroxidase activities in skeletal muscle did not differ significantly among the groups. These results indicate that carnosine may improve swimming exercise capacity by attenuating production of lactate and reducing oxidative stress in mice.
        4,300원
        5277.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        한국원자력연구원의 연구지역에서 고준위방사성폐기물처분을 위한 부지특성평가 기술 구축을 위해 지질특성조사가 1997년부터 지표기반 조사, 시추공 조사를 포함하여 수행되었다. 2006년에는 지하처분연구터널(KURT, KAERI Underground Research Tunnel)을 준공하여 연구지역에 대한 심부지질환경 규명을 위해 노력하고 있다. 본 연구는 한국원자력연구원내 건설된 지하처분연구시설 주변 지역을 연구대상지역으로 하여 지질모델에 대한 수리지질모델의 통합 구축을 목적으로 한다. 본 연구를 위해 연구지역에서 굴착된 9개의 시추공에 대한 현장 수리시험 자료를 이용하였으며, 지질모델에서 도출한 풍화대, 상부저경사단열대, 심부 영역에 존재하는 결정론적 단열대에 대한 수리지질특성을 분석하였다. 본 연구 결과제시된 수리지질모델은 향후 지하수 유동모델링에 이용될 것이다.
        4,000원
        5278.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We study the relationships between the thermal emissivity of nuclear graphites (IG-110, PCEA, IG-430 and NBG-18) and their surface structural change by oxidation using scanning electron microscope and X-ray diffraction (XRD). The nonoxidized (0% weight loss) specimen had the surface covered with glassy materials and the 5% and 10% oxidized specimens, however, showed high roughness of the surface without glassy materials. During oxidation the binder materials were oxidized first and then graphitic filler particles were subsequently oxidized. The 002 interlayer spacings of the non-oxidized and the oxidized specimens were about 3.38~3.39a. There was a slight change in crystallite size after oxidation compared to the nonoxidized specimens. It was difficult to find a relationship between the thermal emissivity and the structural parameters obtained from the XRD analysis.
        4,000원
        5279.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Larix kaempferi is a tree with a major economic impact and is processed in large quantity every year in Korea. This study was carried out to collect basic data for the reasonable use of Larix kaempferi and to investigate the relation between anatomical properties and modulus of rupture (MOR) for heartwood and sapwood. As the length of earlywood tracheid and the radial wall thickness of earlywood tracheid and latewood tracheid increased, the modulus of rupture (MOR) increased, but decreased with increasing microfibril angle. Statistical analysis by the stepwise regression technique shows that the main factors affecting the modulus of rupture (MOR) of heartwood are the microfibril angle and the radial wall thickness of latewood tracheid, while those affecting MOR of sapwood are the length of earlywood tracheid and the microfibril angle.
        4,000원
        5280.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        HACCP is applicable when there are control measures which can be applied to prevent, eliminate, or reduce the occurrence of a food safety hazard to a consumer, but much of the life cycle of a food does not lend itself to strict application of HACCP principles. FSIS HACCP is mandatorily applied to meat and poultry slaughter and processing establishments to reduce harmful bacteria on their products. FSIS manages the HACCP plants under continuous inspection of the FSIS inspectors: Inspector in Charge (IIC), Public Health Veterinarian (PHV), on line/off line Consumer Safety Inspectors (CSI). More than 7,600 inspection personnel inspect nearly 6,500 meat, poultry, and egg processing plants, and verify that regulations regarding food safety and other consumer protection concerns are met. But only half of violations observed are recorded on the non-compliance report due to inspector shortages. The change from traditional sanitation system to HACCP system has been difficult because of several factors: Lack of technical expertise in processing facilities makes a scientific hazard analysis difficult, preventive measures and validation efforts are not supported by data, plant management and inspectors concentrate on what they know, plants are still very dependent on the regulatory agency for guidance, focus is on regulatory procedures more than determining food safety issues, and also plants are less efficient at producing and maintaining records that are not specifically tied to production lots. However HACCP is an effective tool in food safety continuum.
        4,000원