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        검색결과 900

        102.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적:간 역동적 검사 시 호흡이 불규칙하거나 호기 후 정지의 어려움을 갖는 환자의 경우 영상의 질이 저하된다. 이 문제점을 해결하기 위해서 GRAPPA, CAIPIRHINA, Compressed Sensing 기법을 사용하여 호흡 정지 시간을 단축하고 있다. 본 연구에서는 acceleration factor 8, 9, 10을 적용한 CS 기법과 초기 동맥기와 동맥기를 동시에 얻을 수 있는 Double arterial phase 기법을 사용하여 VIBE 영상을 얻어 비교함으로써 최적 acceleration factor 값과 phase를 평가해보고자 한다. 대상 및 방법:2019년 8월 19일부터 9월 20일까지 본원에서 간 MRI 검사를 시행한 환자 15명을 대상(남자 10명 여자 5명 64±12.6세)으로 단일 호흡 정지 동안 2번 측정되는 double phase image를 사용할 때, acceleration factor를 각각 8, 9, 10으로 변화를 주고 다른 변수들은 같게 하여 실험을 진행하였다. 획득한 acceleration factor 값과 phase가 다른 각 영상의 SNR, CNR을 측정하여 정량적 평가를 진행하고, 정성적 영상평가와 호흡 정지 시간의 변화를 비교하였다. 결과:같은 phase에서 acceleration factor의 값이 9, 10, 8 순으로 SNR이 높았으며, acceleration factor가 8, 10일 경우 SNR이 phase 1보다 phase 2가 높았고, acceleration factor가 9일 경우에는 phase 1가 더 높았다. phase 1의 CNR은 acceleration factor 9, 8, 10 순으로 높았고, phase 2에서의 CNR은 acceleration factor 9, 10, 8 순으로 높았다. acceleration factor가 8, 9인 경우는 phase 1의 CNR이 높았고, 10인 경우 phase 2의 CNR이 높았다. 결론:본 연구의 실험결과를 종합하였을 때 acceleration factor 9를 적용한 double phase image 중 Phase 1에서 가장 높은 SNR과 CNR을 확인할 수 있었다. 또한, 호흡 정지시간 역시 acceleration factor 8 대비 acceleration factor 9에서는 13% 감소하고, acceleration factor 10에서는 20% 감소한 효과를 얻었다. CS 기법을 사용한 간의 역동적 Double Phase 검사 시 영상의 질의 변화에 큰 유의함이 없는 상태로 acceleration factor를 조절하여 호흡 정지시간을 줄이고, 2개의 영상 중 선택하여 임상적으로 활용할 수 있다고 생각한다.
        4,000원
        103.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The latest issue is the smart factory. In order to implement this smart factory, the most fundamental element is to establish product specifications for factors affecting the product, obtain useful data to analyzed and predicted, and maintain safety. But most manufacturers have many errors. Therefore, the purpose of this study is to verify factors of product through statistical techniques and to study the process control and safety.
        4,000원
        105.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chronic hypoxia is a major cause that increases neonatal mortality in the perinatal period. Vascular endothelial growth factor (VEGF) and its receptors induced by hypoxia are increased blood vessel permeability in the developing central nervous system and characterized as a critical factor in angiogenesis and vasculogenesis. This study investigated the development of the rat cerebellum with expression of VEGF and its receptors under chronic hypoxia in compare with normoxia. In addition, this study can contribute to the understanding of the effect development in the postnatal cerebellum. Rat pups were divided into two groups, normoxia and hypoxia group. The cerebellum of 35-day-old rat was removed and prepared for immunofluorescent staining. After staining, the sections were observed under the fluorescent microscope and were taken the picture using the microscopic-digital camera system. Expression of VEGF and Flk-1 restricted only to Purkinje cells, but feline sarcoma virus-like tyrosine kinase-1 (Flt-1) did not express in all of cerebellar layers. Under chronic hypoxia, expression of VEGF and fetal liver kinase-1 (Flk-1) increased in Purkinje cells but no changes in case of Flt-1. These results suggest that the source of VEGF and Flk-1 is Purkinje cells in the cerebellum. And increase of VEGF and Flk-1 expression in the murine cerebellum results from adaptive responses to chronic hypoxia.
        4,000원
        111.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study establishes a pay adjustment factor scheme that will penalize or provide incentives to contractors after pavement construction in Seoul City. METHODS: Random sampling was conducted, wherein acceptable quality characteristics (AQCs) of the field mixture such as the aggregate gradation, asphalt binder content, pavement thickness, field air void, and IRI (International Roughness Index) were determined. Using the acquired field data, the percent within limit (PWL) values of each AQC were determined. RESULTS : Weight factors were used to consider the effect of each AQC, since field data varies depending on the field condition. The total pay factor (PF) was determined by combining the PF material and PF construction. PF material considers the asphalt binder content and the aggregate gradation, while PF construction considers the field air void, pavement thickness, and field IRI. CONCLUSIONS: A pay adjustment factor was established by determining the PWL of each AQC and calculating the corresponding pay factor. Based on the results, it is found that PWL is a reasonable and acceptable method for evaluating the pavement quality and determining the pay factor.
        4,000원
        112.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Despite frequent shoulder injuries of rotator cuff muscle of golfers by the result of overuse and poor swing mechanics, there is little research on shoulder specific rehabilitation exercises for injured rotator cuff muscle and golf swing Objective: To examined the effect of rehabilitation exercise for golfers on the X factor and ground reaction force (GRF) according to phase of the golf swing. Design: Crossover study Methods: The participants were 13 amateur golfers selected for a 4 week rehabilitation exercise for golfers. A rehabilitation exercise for golfers consisting of 5 steps and 4 items (sleeper stretch, full side plank, push up to plank, high plank knee unders) were applied to all participants. A three dimensional motion analyzer and force platform (SMART-E, BTS, Italy) were used to measure the X factor (angle between shoulder and pelvis at top of back swing) and GRF according to phase of the golf swing. All dependent variables were measured before and after exercise. The collected data was analyzed using the paired t test and SPSS 21.0. Results: The GRF had a statistically significant increase in the impact phase and ratio impact/weight after rehabilitation exercise for golfers (p<.05). The Xfactor, GRF in top of back swing and finish were no significant differences between before and after exercise (p>.05). Conclusions: These results suggested that rehabilitation exercise for golfers was effective for increasing GRF in the impact phase and ratio impact/weight for amateur golfer.
        4,000원
        113.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        제조업이 국가경제에서 차지하는 중요성에도 불구하고 고용비중의 급격한 감소는 한국을 포함한 선진국이 당면한 공통의 문제이다. 그 중에서도 과학기술 일자리는 고용의 질과 산업경쟁력에 직결되기 때문에 정책적 차원에서 중요성하나 이에 대한 선행연구는 미진 한 편이다. 본 연구에서는 제조업을 기술체제에 따라 세분화하고 신제품 개발, 신공정 개발, 개 방형 혁신, 정부 R&D지원이 과학기술 일자리 창출에 미치는 영향을 분석하였다. 분석결과 신제품 개발은 과학기술 일자리 확대에 기여하나 신공정 개발은 과학기술 일자리를 감소시키는 것으로 확인되었다. 또한 개방형 혁신은 연구개발 기능의 아웃소싱으로 인해 과학기술 일자리를 감소시키는 효과가 있으며, 정부 R&D 지원은 기술혁신에 대한 수요가 낮은 전통산업의 과학기술 일자리 창출에 기여하는 것으로 나타났다.
        5,800원
        118.
        2018.11 구독 인증기관·개인회원 무료
        This study was conducted to evaluate the effects of insulin and epidermal growth factor (EGF) in a in vitro growth (IVG) medium on oocyte growth, in vitro maturation (IVM) and embryonic development of pig oocytes derived from small antral follicles (SAF) less than 3 mm in diameter. SAF oocytes were cultured for 2 days to induce IVG in alpha-minimal essential medium supplemented with 1 mM dbcAMP and 15% (v/v) fetal bovine serum. After IVG culture, oocyte maturation was induced by culturing IVG oocytes in IVM medium for 44 h. IVM oocytes that extruded the first polar body were selected and induced for parthenogenesis (PA) by applying electric stimulus. SAF oocytes cultured under the insulin treatment showed a significantly increased (P < 0.05) nuclear maturation (73.8%) compared to those cultured with insulin and EGF (59.8%). After PA, the proportions of blastocysts based on the number of metaphase II oocytes were significantly higher (P < 0.05) in oocytes that were cultured for IVG with insulin, EGF, and insulin + EGF (32.4%, 35.2%, and 34.8%, respectively) than in control (22.9%). IVG oocytes treated with insulin showed an increased oocyte diameter (116.3 μm) compared to those treated with insulin and EGF (114.0 μm) (P < 0.05). Intra-oocyte GSH content significantly increased (1.07 pixels/oocyte) by insulin treatment during IVG compared to that of oocytes treated with insulin + EGF (0.78 pixels/oocyte). These results demonstrate that IVG culture of SAF oocytes under insulin or/and EGF treatment supports oocyte maturation and improves embryonic development to the blastocyst stage after PA in pigs.