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        검색결과 9,762

        4670.
        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
        4671.
        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
        4672.
        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
        4673.
        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
        4674.
        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
        4675.
        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
        4676.
        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
        4677.
        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
        4678.
        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
        4679.
        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
        4680.
        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