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        검색결과 3,479

        706.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Vibration stimulation has emerged as a treatment tool to help reduce spasticity during physical therapy. Spasticity includes problems of reduced range of motion (ROM) and stiffness. However, the benefits of vibration rolling (VR) on interventions for stroke patients are unclear. Objectives: This study aimed to investigate the effect of VR intervention on the ankle ROM and ankle stiffness in stroke patients. Design: A randomized crossover study. Methods: Seven stroke patients completed two test sessions (one VR and one non-VR [NVR]) in a randomized order, with 48 hours of rest between each session. Participants completed intervention and its measurements on the same day. The measurements included ankle dorsiflexion and plantarflexion ROM and stiffness of ankle muscles, including the tibialis anterior, medial, and lateral gastrocnemius muscle. Results: After VR, ankle dorsiflexion ROM, lateral gastrocnemius stiffness, and medial gastrocnemius stiffness improved significantly (all P<.05). After NVR, only the lateral gastrocnemius stiffness improved significantly (P<.05). Furthermore, in the cases of changed values for ankle dorsiflexion ROM and lateral gastrocnemius stiffness were compared within groups, VR showed a more significant difference than NVR (P<.05) Conclusion: VR improved ankle ROM and muscle stiffness. Therefore, we suggest that practitioners need to consider VR as an intervention to improve dorsiflexion ROM and gastrocnemius stiffness in stroke patients.
        4,000원
        707.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 정상안에서 조도에 따른 눈의 굴절력과 동공 크기의 동적변화를 측정하고, 동공 중심점의 이동량과 방향을 알아보고자 하였다. 방법 : 2020년 7월부터 2020년 9월까지 경기도 지역 안경원에 원용 안경 처방을 위해 내원했던 안과적인 질환 및 각막 굴절 교정 수술 경험 없는 성인 29명(남 14명, 여 15명) 58안을 검사하였고, 평균 나이는 35.62±14.48세였다. 전자동 수차 분석기를 이용하여 조도에 따른 눈의 굴절력, 동공 중심점의 변화 값을 측정하 였고, 각각 3회씩 측정하여 평균값을 사용하였다. 통계 프로그램 SPSS를 이용하여 조도 변화에 따라 명소시와 암소시에서의 굴절력, 그리고 동공 중심의 이동량을 비교 분석하였다. 결과 : 조도에 따라 구면 굴절력은 –2.80 D에서 -2.94 D로 평균 –0.14 D 만큼 변화하였다(p<0.001). 원주 굴 절력은 –0.93 D에서 -0.98 D로 평균 –0.05 D가 증가하였다(p<0.001). 동공 중심점의 평균 이동량은 수평 방향으로 0.14 mm, 수직 방향 0.13 mm만큼 이동하였다. 방향 별 동공 중심점 이동은 양안에서 상측 35안(60.3%), 하측 20안(34.5%), 코측 25안(43.1%), 귀측 33안(56.9%) 이동하였다. 양안에서 동공 중심점 이동은 수평방향으 로 높은 상관관계가 있었고(r=0.700), 수직방향으로는 낮은 상관관계가 있었다(r=0.244). 결론 : 조도가 어두워질수록 구면굴절력은 (-)방향으로 커지고, 동공 크기가 증가하며, 동공 중심은 수평과 수직 방향으로 모두 이동하였다. 따라서 야간 활동 안경렌즈를 조제할 때는 굴절력 변화와 동공 중심 이동에 따른 시력의 질적 저하를 고려해야 할 것으로 생각된다.
        4,000원
        708.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Demethoxycurcumin (DMC), which is a curcuminoid found in turmeric, has anti-proliferative effects on cancer cells. However, the effect of DMC on osteosarcoma has not been established. The aim of this study was to examine the effects of DMC on cell growth and apoptosis induction in MG-63 human osteosarcoma cells. This study was investigated using 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromid assay, Live/Dead cell assay, 4’, 6-diamidino-2-phenylindole staining, and immunoblotting in MG-63 cells. DMC induced MG-63 cell death in a dosedependent manner, with an estimated IC50 value of 54.4 μM. DMC treatment resulted in nuclear condensation in MG-63 cells. DMC-induced apoptosis in MG-63 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting results showed that Bcl-2 and Bcl-xL were downregulated, while Bax and Bad were upregulated by DMC in MG-63 cells. These results indicated that DMC inhibits cell proliferation and induces apoptotic cell death in MG-63 human osteosarcoma cells via the death receptormediated extrinsic apoptotic pathway and mitochondria-mediated intrinsic apoptotic pathway.
        4,000원
        709.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 낮은 가입도의 근시성 노안을 대상으로 중심-근용 및 중심-원용 동시보기 멀티포컬 콘택트렌즈 착용 후 시기능을 비교하고자 하였다. 방법 : 13명(46.92±5.91세)의 대상자들을 중심-근용 및 중심-원용 동시보기 멀티포컬 콘택트렌즈를 각각 착용 후 조절래그, 스트레이라이트, 입체시력, 수평사위, 근거리 버전스, 자각적 시력 만족도를 평가하였다. 결과 : 낮은 가입도의 근시성 노안을 대상으로 중심-원용 및 중심-근용 동시보기 멀티포컬 콘택트렌즈 사이에서 조절래그, 스트레이라이트, 입체시력, 수평사위, 근거리 버전스, 자각적 시력 만족도는 유의한 차이가 없었다. 결론 : 낮은 가입도의 근시성 노안에서 중심-근용 및 중심-원용 동시보기 멀티포컬 콘택트렌즈 착용 후 시력의 질 그리고 조절 및 버전스 반응과 관련된 시기능에서 유의한 차이가 없었다. 따라서 멀티포컬 콘택트렌즈 선택 시 참고자료로 활용할 수 있으리라 생각된다.
        4,200원
        710.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.
        4,000원
        711.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 안경광학과 대학생의 건강관리 실태와 눈 건강상태를 조사하여 건강관련 특성요인을 파악하고 눈 건강에 미치는 영향을 확인하고자 한다. 방법 : 충남지역 안경광학과 대학생 196명에게 온라인으로 일반적 특성(3)과 건강관련 특성(7), 지각된 눈 건강상태(5)의 총 15개 문항을 설문 조사하였다. 지각된 눈 건강상태는 리커트 5점 척도를 사용하였으며, 점수가 높을수록 눈 건강상태가 나쁘다. 분석방법은 SPSS 18.0 통계프로그램을 사용하였으며 통계적으로 유의수준은 p<0.050 기준으로 하였다. 결과 : 흡연을 하는 학생은 눈 건강상태 중 눈의 피로감과 충혈 증상, 눈꺼풀이 무겁다고 느끼는 정도가 많았다. 일주일동안 운동 횟수가 5회 이상인 학생은 눈의 피로감과 충혈 증상이 적었고, 규칙적인 식사를 하는 경우 눈의 충혈 증상이 적었다. 여가활동 시간이 긴 학생은 눈의 충혈과 눈꺼풀이 무겁다고 느끼는 정도가 적었고, 주 관적 건강상태가 좋다고 응답한 학생은 눈의 피로감과 통증, 눈꺼풀 무겁다고 느끼는 정도가 적었다. 주관적 건강 상태는 눈 건강상태와 음의 상관관계로 주관적 건강상태가 나쁠수록 눈 건강상태의 좋지 않았다. 결론 : 안경광학과 대학생들은 건강의 기본이 되는 규칙적인 식사와 운동을 소홀히 하고 있었으며, 주관적 건강상태와 운동 횟수, 여가활동 시간이 눈 건강에 영향을 미치는 것을 확인하였다. 따라서 본 연구를 통해 예비 안경사인 안경광학과 대학생들은 스스로의 건강행위를 지각하여 규칙적인 식사와 운동, 여가활동 등의 건강한 습관 형성과 눈 건강관리의 중요성에 대해 인지할 필요가 있다.
        4,000원
        712.
        2021.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.
        4,000원
        713.
        2021.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Developments in cancer therapies and diagnostic techniques have improved the long-term survival of cancer patients. Certain cancer treatments, such as radiotherapy, often harm normal tissue as well as the specifically targeted cancer cells. High doses of radiation induce bone loss. This study investigated the effects of pentoxifylline (PTX) on radiation-induced bone loss in C3H/HeN mice. C3H/HeN mice were divided into sham and irradiation (3 Gy, gamma-ray, IR) groups. The irradiated mice were treated for 12 weeks with vehicle, PTX (p.o.) or PTX (s.c.). Grip strength, uterus weight, serum alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) level were measured. Tibiae were analyzed using micro-computed tomography. There were no significant differences in the degree of grip strength, body weight and uterine weight between IR group and PTX-treated group. Treatment of PTX significantly preserved trabecular bone volume, trabecular number, trabecular separation and bone mineral density of proximal tibia metaphysic. The administration of PTX lowered serum TRAP in IR mice, suggesting that PTX can reduce the bone resorptive rate in mice. Our experimental data support the protective role of PTX against bone loss in irradiated mice. Based on the findings of this study, development of PTXbased treatments is anticipated to address bone loss after radiotherapy. Prospective dose escalation studies are required to determine the appropriate dosage of PTX.
        4,000원
        714.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Annual military exercise has been performed between the two countries, R.O.K and USA, ever since the formation of military alliances. Also, this drill has been relatively well done. But it has been shocking to the internal Korean society the annual military drill, the formal consensus between South Korea and United States, hindered by the a few NGOs for 50 minutes in march, 2006. And also, there has been doing another kind of civil war in peacetime among the local farmers, NGOs, the policemen and even the military for the land in Pyongtaek in three months. We, Koreans, are too much confused to be seen by these two cases. Quo va dis, Korean society? Let democracy work? How is to be done the national project under these circumstances? Right after the 6.29 'Democratization Declaration'(1987), the peoples of South Korea have been proud of accomplishing the democratization, in spite of the fact that there is no citizen revolution like the western countries, successively holding 1988 Summer Olympics. South Korea becomes the open society. In 1993, with the advent of the real civilian government, there has been suddenly roaring up the diverse groups of the eruptive participation in all respects of South Korea. In the meanwhile, there is one exceptional spheres not to open to the civil society. This may be the common phenomenon across the continent. There is really no more mediation to solve the military chaos in “young democracy in Asia.” In case of South Korea, there will be the destinations going for the democratic society. South Korea has been facing the turning points for the time-consuming national project on the construction of a nuclear dump made by a resident's referendum. One of South Korea's long-term tasks, which has been embroiled in conflict for the past 19 years, may find a solution through the first experiment, a resident's referenda. Although Aomori prefecture in Japan decided to host a nuclear waste interim storage facility, there is no referendum, or citizen's vote, in Mutsu city in the prefecture, where the facility will be constructed. What we try to do in this paper is to review the range, question, aftermath of the military intervention in citizen affairs. And this paper calls attention to the central problem as to the problem-solving methods for in the case of colliding with the contracting values, peace or security.
        5,700원
        715.
        2021.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Celecoxib, a cyclooxygenase (COX)-2 selective inhibitor, was approved as a non-steroidal anti-inflammatory drug (NSAID), and this therapeutic application has been expanded to several other diseases, including colon cancer. Notably, a treatment strategy combining the use of celecoxib and radiation therapy has been employed for improving the control of local cancers. In this study, we examined the effect of celecoxib on irradiation-induced intestinal damage. The twenty four mice (BALB/c) were divided into four groups; 1) sham-irradiated control group, 2) celecoxib-treated group, 3) irradiated group, and 4) celecoxib-treated irradiation group. Mice were orally administered celecoxib at a dose of 25 mg/kg in a 0.1 mL volume, daily for 4 days after irradiation exposure (10 Gy). Then, histological examinations of the jejunal villous height, crypt survival, and crypt size were performed. The expression of COX-2 after administration of celecoxib in irradiated mice was examined by employing immunohistochemistry, Western blotting, and qPCR analysis. The jejunal villi height and the crypt survival were reduced in the irradiation group compared with the sham-irradiated group. Celecoxib treatment in irradiation mice even more decreased those indicators. Crypt size was increased in the radiation group compared to the sham-irradiated control group, whereas the size was decreased in the celecoxibtreated irradiation group compared with the group exposed to the radiation injury. COX-2 expression was detected in the crypt of the small intestine, and COX-2 expression was increased in the crypt lesion following radiation exposure. However, COX-2 expression was reduced in the celecoxib-treated irradiation group. Therefore, in the present study, we confirmed that celecoxib treatment after irradiation aggravated the irradiation-induced intestinal damage. These results suggest that a caution need to be administered when celecoxib treatment is performed in combination with radiation therapy for cancer treatment.
        4,000원
        716.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        마케팅과 R&D의 상대적 비중으로 측정되는 전략적 강조(strategic emphasis)가 기업 성과에 어떠한 영향을 미치는 지는 주로 미국 상장 기업들의 자료에 의존하여 연구 되어 왔다. 하지만 이 머징마켓의 중요성이 증대되고 국가간 경제의 상호의존성이 높아지고 있음을 고려할 때, 전략적 강 조가 기업 성과에 미치는 영향이 선진국 뿐만 아니라 이머징마켓에서도 나타나는지를 살펴보는 연 구는 중요하다고 할 수 있다. 따라서 본 연구는 중국 시장에 상장된 기업들의 자료를 분석하여 전 략적 강조가 중국 상장 기업들의 성과에 어떠한 영향을 미치는지를 살펴보고 더 나아가 그 영향이 선진국인 미국과 이머징 마켓인 중국에서 어떻게 다른지 비교하고 있다. 또한 상당수의 중국 기업 들이 국영기업들임을 감안할 때, 국영기업에서 전략적 강조의 효과가 감소 또는 증대되는지를 살펴 본다. 중국과 미국 기업들의 자료를 분석한 결과, 중국 시장에서 전략적 강조가 기업 성과에 긍정 적인 영향을 미치며, 그 영향은 미국에서 보다 중국에서 더 크게 나타났다. 또한, 전략적 강조의 기 업 성과에 대한 긍정적인 영향이 중국의 국영기업일수록 줄어드는 것으로 나타났다. 이와 같은 연 구 결과는 기업들이 한정된 자원을 가치 창출 활동과 가치 전유 활동에 어떻게 배분하는지에 따라 기업 성과가 달라지고, 또한 시장 환경에 따라 자원배분 효과가 달라진다는 점을 의미하여 다국적 기업의 글로벌전략 수립에 중요한 시사점들을 제시한다.
        6,400원
        717.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        혁신은 특히 신흥국가 시장에 속한 기업들에게 도전적인 일이다. 5% 이상 지분을 소유한 소위 블록 기관투자자는 기업 혁신에 있어 중요한 역할을 맡고 있다. 본 연구는 중국 증시에 상장된 기 업들을 표본으로 블록 기관투자자들이 기업혁신의 성과에 미치는 영향을 분석하였다. 주요 연구자 료로서 기업이 허가받은 발명 특허의 건수를 사용하여 기업혁신의 성과를 측정하였다. 2007년부터 2016년까지 1,126개 중국 기업의 패널 데이터를 사용하여 분석한 결과, 블록 기관투자자는 기업 경영에 대해 적극적인 모니터링을 수행하며, 경영진의 커리어 우려를 해소시킴으로써 기업의 혁신 성과에 긍정적인 영향을 미치고 있음을 발견하였다. 어떤 유형의 블록 기관투자자가 보다 유의한 영향을 미치는지를 분석하기 위하여 기관투자자의 국적과 투자기간에 따라 블록 기관투자자를 국 내 블록 기관투자자와 해외 블록 기관투자자, 그리고 장기적 블록 기관투자자와 단기적 블록 기관 투자자로 구분하였다. 실증분석 결과, 국내 및 해외의 블록 기관투자자는 모두 중국기업의 혁신 성 과에 유의하게 긍정적인 영향을 미치고 있었다. 특히 해외의 장기적인 블록 기관투자자의 긍정적인 영향이 가장 크게 나타났다. 반면에 단기적인 블록 기관투자자가 혁신 성과에 미치는 영향은 통계 적으로 유의하지 않았다. 이런 분석 결과들은 강건성 테스트에서도 일치하게 나타났다.
        10,100원
        718.
        2021.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The characteristics and morphology of precipitated calcium carbonate (PCC) particles produced by carbonation process with various experimental conditions are investigated in this study. The crystal structures of PCC formed by carbonation process are calcite and aragonite. The crystal structure of PCC particles synthesized without adipic acid additive is calcite only, regardless of the reaction temperature. Needle-like shape aragonite phase started to form at reactor temperature of 80°C with the adipic acid additive. Particle size of the single phase calcite PCC synthesized without adipic acid additive is about 1 ~ 3 μm, with homogenous distribution. The aragonite PCC also shows uniform size distribution. The reaction temperature and concentration of adipic acid additive do not show any significant effects on the particle size distribution. Aragonite phase grown to a large aspect ratio of needle-like shape showed relatively improved whiteness. The measured whiteness value of single calcite phase is about 95.95, while that of the mixture of calcite and aragonite is about 99.11.
        4,000원
        719.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, soybean oil, which is used in a large variety of processed foods, is used as a carbon source. Soybean oil is successfully coated onto the surface of LiNi1/ 3Co1/3Mn1/3O2 (NCM) by a simple method. The physical and electrochemical properties of NCM/C hybrid materials are determined. As a result, a 5 nm thickness carbon coating layer is formed on the surface of the NCM, resulting in improved capability and cyclic performance in the battery. The NCM/C battery shows an initial discharge capacity of 159 mAh g−1 and 95% capacity retention after 100 cycles (a discharge capacity of 120 mAh g−1 and 94% retention are observed after 100 cycles for the NCM cathode).
        4,000원
        720.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Continuous synthesis of high-crystalline carbon nanotubes (CNTs) is achieved by reconfiguring the injection part in the reactor that is used in the floating catalyst chemical vapor deposition (FC-CVD) process. The degree of gas mixing is divided into three cases by adjusting the configuration of the injection part: Case 1: most-delayed gas mixing (reference experiment), Case 2: earlier gas mixing than Case 1, Case 3: earliest gas mixing. The optimal synthesis condition is obtained using design of experiment (DOE) in the design of Case 1, and then is applied to the other cases to compare the synthesis results. In all cases, the experiments are performed by varying the timing of gas mixing while keeping the synthesis conditions constant. Production rate (Case 1: 0.63 mg/min, Case 2: 0.68 mg/min, Case 3: 1.29 mg/min) and carbon content (Case 1: 39.6 wt%, Case 2: 57.1 wt%, Case 3: 71.6 wt%) increase as the gas-mixing level increases. The amount of by-products decreases stepwise as the gas-mixing level increases. The IG/ID ratio increases by a factor of 7 from 10.3 (Case 1) to 71.7 (Case 3) as the gas-mixing level increases; a high ratio indicates high-crystalline CNTs. The radial breathing mode (RBM) peak of Raman spectrograph is the narrowest and sharpest in Case 3; this result suggests that the diameter of the synthesized CNTs is the most uniform in Case 3. This study demonstrates the importance of configuration of the injection part of the reactor for CNT synthesis using FC-CVD.
        4,000원