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        검색결과 5,770

        521.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250oC.
        4,000원
        522.
        2023.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The second generation of stars in the globular clusters (GCs) of the Milky Way (MW) exhibit unusually high N, Na, or Al, compared to typical Galactic halo stars at similar metallicities. The halo field stars enhanced with such elements are believed to have originated in disrupted GCs or escaped from existing GCs. We identify such stars in the metallicity range −3.0 < [Fe/H] < 0.0 from a sample of ∼36,800 giant stars observed in the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey, and present their dynamical properties. The N-rich population (NRP) and N-normal population (NNP) among our giant sample do not exhibit similarities in either in their metallicity distribution function (MDF) or dynamical properties. We find that, even though the MDF of the NRP looks similar to that of the MW’s GCs in the range of [Fe/H] < −1.0, our analysis of the dynamical properties does not indicate similarities between them in the same metallicity range, implying that the escaped members from existing GCs may account for a small fraction of our N-rich stars, or the orbits of the present GCs have been altered by the dynamical friction of the MW. We also find a significant increase in the fraction of N-rich stars in the halo field in the very metal-poor (VMP; [Fe/H] < −2.0) regime, comprising up to ∼20% of the fraction of the N-rich stars below [Fe/H] = −2.5, hinting that partially or fully destroyed VMP GCs may have in some degree contributed to the Galactic halo. A more detailed dynamical analysis of the NRP reveals that our sample of N-rich stars do not share a single common origin. Although a substantial fraction of the N-rich stars seem to originate from the GCs formed in situ, more than 60% of them are not associated with those of typical Galactic populations, but probably have extragalactic origins associated with Gaia Sausage/Enceladus, Sequoia, and Sagittarius dwarf galaxies, as well as with presently unrecognized progenitors.
        4,800원
        523.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Elastic and non-elastic taping are widely used in clinical practice, but there are various methods of attachment. Objectives: To investigate the effect of the type and intensity of taping on the muscle strength and muscle endurance of healthy adults. Design: Experimental research. Methods: 38 healthy adults participated in this experiment. Before applying the taping to each participant, the muscle strength and endurance of the quadriceps femoris were measured. After applying three different taping intervention methods, muscle strength and muscle endurance changes were measured. Muscle strength and endurance were measured through CSMI. Repeated measures ANOVA was used for statistics on participant measurements. Results: All intervention methods influenced the muscle strength improvement of the quadriceps femoris. Elastic tape with 50% elasticity had a greater impact on muscle strength than 33% elastic tape and non-elastic tape, and secondly, elastic tape with 33% elasticity was effective, and non-elastic tape had the least impact. Muscle endurance improvement was affected by the order of 50% elasticity taping, 33% elasticity taping, and non-elastic taping. Conclusion: All three taping intervention methods showed significant effects on improving muscle strength and muscle endurance of the wide-legged quadruple muscles, but the best effect was to apply 50% elastic taping.
        4,000원
        524.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: The application of exercise therapy and manual therapy to the thoracic spine is a widely used method of treating neck pain. Nevertheless, studies on the application of foam rollers and vibrating foam rollers to patients with neck pain are lacking. Objectives: To investigated the immediate effects of thoracic spine foam rolling and vibration foam rolling on pain and range of motion (ROM) in patients with chronic neck pain. Design: Randomized crossover trials. Methods: 24 patients with chronic neck pain participated in the study. The study subjects measured pain and ROM. Subjects were divided into vibration foam roller group, foam roller group, and control group. Results: Pain was not significantly different between and within groups (P<.05). There was a significant difference in flexion, extension, left rotation, and right rotation ROM in the vibration foam roller group after intervention (P<.05). There was a significant difference in flexion and extension ROM in the foam roller group after intervention (P<.05). There was a significantly greater increased extension ROM in vibration foam roller and foam roller groups compared with the control group (P<.0167). Conclusion: Thoracic spine foam rolling and vibration foam rolling improve ROM when treating patients with chronic neck pain. Therefore, it is recommended to use it in combination with other treatments
        4,000원
        525.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Pain Neuroscience Education (PNE) is an educational approach that deals with the physiology of the nervous system as well as the pain system and refers to educating patients with chronic musculoskeletal disorders such as chronic back pain. Objectives: This study examined the effects of pain neuroscience education on patients with low back pain. Design: Systematic review. Methods: Electronic bibliographic databases of a regional information sharing system (RISS) and PubMed were searched to identify randomized controlled studies. In the final outcome, 43 publications were identified, and 13 studies met the inclusion criteria. Results: There were a total of 13 pain-related studies, including 11 studies using NPRS (VAS) and 2 studies using other pain measurement instruments. In NPRS, the effect size was 0.683, which had a medium effect size. In Roland morris disability questionnaire (RMDQ), the effect size was 0.544, which had a medium effect size. In Oswestry disability index (ODI), the effect size was 0.951, indicating a large effect size, but the confidence interval could not be obtained because there was only one study. Conclusion: Pain neuroscience education has positive effects on low back pain and disability index in related patients.
        4,000원
        526.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Total hip replacement (THR) is performed in patients with femur fractures and osteoarthritis. THR patients have balance problems even after surgery. There is a lack of research on vibration stimulation interventions for balance in THR patients. Objectives: To investigated the effect of vibration stimulation intervention on the balance and gait of THR patients. Design: Randomized controlled trials. Methods: 44 subjects were randomly assigned to a vibration stimulation group (VSG) and a non-vibration stimulation group (N-VSG). Seven study subjects dropped out, and 37 completed the study. Timed up and go (TUG) and Berg balance scale (BBS) were used for balance assessment, and 10-meter walk (10MW) was used for gait assessment. The intervention program was conducted three times a week for 4 weeks. Results: Significant differences within the groups in balance (BBS, TUG) and gait (10MW) between the VSG and the N-VSG. There was no difference between the two groups in any variable. Conclusion: The VSG improved the balance and gait of THR patients without any difference from the N-VSG. However, VSG showed a higher effect size than N-VSG.
        4,000원
        527.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A strain of Amphidinium species was established from samples collected from the intertidal zone of a sandy beach of Jeju Island, Korea. Its cells were 13.0-15.0 μm in length and 10.0-13.0 μm in width. Its cell shape was round or oval and dorsoventrally flat. A pyrenoid was located in the center of the cell and a nucleus was posteriorly located. Its epicone was small and left-deflecting. Its cingulum had V-shape on the ventral side, forming a ventral ridge and extending to the sulcus. Polygonal amphiesmal vesicles and ring-shaped body scales not described previous were observed on the surface of the cell. Its morphological features were consistent with those of previously described Amphidinium fijiense. Phylogeny based on ITS region and LSU rDNA sequences revealed that this Amphidinium isolate was clearly clustered with other A. fijiense strains, but separated from other Amphidinium species. These results indicate that this Amphidinium isolate is A. fijiense. This study reports its presence for the first time in the intertidal zone of a sandy beach of Jeju Island, Korea.
        4,500원
        528.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Soft magnetic powder materials are used throughout industries such as motors and power converters. When manufacturing Fe-based soft magnetic composites, the size and shape of the soft magnetic powder and the microstructure in the powder are closely related to the magnetic properties. In this study, Fe-Si-Al-P alloy powders were manufactured using various manufacturing process parameter sets, and the process parameters of the vacuum induction melt gas atomization process were set as melt temperature, atomization gas pressure, and gas flow rate. Process variable data that records are converted into 6 types of data for each powder recovery section. Process variable data that recorded minute changes were converted into 6 types of data and used as input variables. As output variables, a total of 6 types were designated by measuring the particle size, flowability, apparent density, and sphericity of the manufactured powders according to the process variable conditions. The sensitivity of the input and output variables was analyzed through the Pearson correlation coefficient, and a total of 6 powder characteristics were analyzed by artificial neural network model. The prediction results were compared with the results through linear regression analysis and response surface methodology, respectively.
        4,000원
        529.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A total of 31 bacterial strains were isolated from the Geum River basin in the Republic of Korea during our investigation of indigenous prokaryotic species. The isolated bacterial strains had high 16S rRNA gene sequence similarity (>98.7%) with those of validly published bacterial species, which have not been reported in Republic of Korea. The 31 bacterial strains were phylogenetically diverse and assigned to 4 phyla, 8 classes, 18 orders, 21 families, and 27 genera. At the genus level, the unreported species were affiliated with Kineococcus, Pedococcus, Rhodoluna, Salinibacterium, Rhodoluna, Arthrobacter, Williamsia, Nakamurella, Nocardioides of the class Actinobacteria, Patulibacter of the class Thermoleophilia, Pontibacter, Hymenobacter of the class Cytophagia, Flavobacterium of the class Flavobacteriia, Geomicrobium of the class Bacilli, Brevundimonas, Gellertiella, Rhizobium, Paracoccus, Taonella, Sphingomonas of the class Alphaproteobacteria, Burkholderia, Polaromonas, Hydrogenophaga, Chitinilyticum, Azospira, Zoogloea of the class Betaproteobacteria, and Pseudomonas of the class Gammaproteobacteria. The unreported bacterial species were further characterized by examining their morphological, cultural, physiological, and biochemical properties. The detailed descriptions of the 31 bacterial strains were provided.
        4,500원
        530.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is essential that continual assessments of the impact of mine-derived water as a long-lasting burden on freshwater environments. Abundance-based evaluations of benthic macroinvertebrates have been conducted to evaluate anthropogenic disturbances and devise policies to reduce their impact. In this study, the status of a stream habitat was evaluated based on the body length and biomass weight of benthic macroinvertebrates of the family Baetidae. Following the renewal of the mining water treatment plant, the abundance of Baetidae assemblages recovered to a level comparable to that of a reference site. However, relatively low values were found for both body length and biomass weight in Baetidae species inhabiting the reddened streambed area, suggesting that the habitat has not yet been completely recovered despite the recovery of the abundance of the Baetidae assemblages. Therefore, continuous investigation and evaluation of this disturbed stream are necessary until their growth conditions of the habitat have functionally recovered
        4,000원
        532.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the effect of lactic acid bacteria (LAB, a mixture of Enterococcus faecium and Lactobacillus plantarum) supplementation, the storage temperature, and storage period on the fermentation characteristics and in vitro ruminal digestibility of a total mixed ration (TMR). The TMR was prepared into two groups, namely, CON (control TMR without the LAB) and ML (supplementing a mixture of E. faecium and L. plantarum in the ratio of 1% and 2% (v/w), respectively). Both groups were divided and stored at 4°C or 25°C for 3, 7, and 14 d fermentation periods. Supplementing LAB to the TMR did not affect the chemical composition of TMR except for the lactate and acetate concentration. Storage temperatures affected (p<0.05) the chemical composition of the TMR, including pH, lactate, and acetate contents. The chemical composition of TMR was also affected (p<0.05) by the storage period. During in vitro rumen fermentation study, the ML treatment showed lower (p<0.05) dry matter digestibility at 24 h incubation with a higher pH compared to the CON. There was no difference in the in vitro dry matter digestibility (IVDMD) of TMR between the CON and ML treatment however, at 24 h, ML treatment showed lower (p<0.05) IVDMD with a higher pH compared to the CON. The effects of storage temperature and period on IVDMD were not apparent at 24 h incubation. In an in vivo study using Holstein steers, supplementing LAB to the basal TMR for 60 d did not differ in the final body weight and average daily gain. Likewise, the fecal microbiota did not differ between CON and ML. However, the TMR used for the present study did include a commercial yeast in CON, whereas ML did not; therefore, results were, to some extent, compromised in examining the effect of LAB. In conclusion, storage temperature and period significantly affected the TMR quality, increasing acetate and lactate concentration. However, the actual effects of LAB supplementation were equivocal.
        4,000원
        533.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Foot-and-mouth disease (FMD) is a very deadly and highly contagious disease that occurs in various cloven-hoofed animals. Korea imports vaccines including non-vaccinated serotype for the vaccine bank. The two company vaccines imported from 2019 to 2021 were evaluated through multiple tests based on national standard assay. SN titers for the vaccine of company A were more than 1.5 log10, those of company B vaccine in the geometric mean were at least 1.72. All imported vaccines exceeded the evaluation criteria, and the potency of each vaccine was above its own company standard. Stockpiled vaccines for emergency may help to control non-vaccinated serotypes of FMD outbreak nationally.
        3,000원
        534.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Subunit vaccines are being developed as a potential therapy for preventing microbial pathogen infection. In this study, the immunogenicity of recombinant Brucella (B.) abortus Fe/Mn superoxide dismutase (rFe/Mn SOD) protein as a subunit vaccine against B. abortus was investigated in BALB/c mice model. Brucella Fe/Mn SOD gene was cloned into a pcold-TF DNA vector. The bacterial recombinant protein was expressed using the Escherichia coli DH5α strain with a size of 82.50 kDa. The western blotting assay showed that rFe/Mn SOD reacted with Brucella-positive serum, indicating the potential immunoreactivity of this recombinant protein. After the second and third vaccinations, the peripheral CD4+ T cell population was increased significantly in the rFe/Mn SOD-immunized mice group compared to the PBS control group. Moreover, immunization of this recombinant protein increased the CD4+ T cell population from the first vaccination to the third vaccination. Meanwhile, the CD8+ T cells were slightly enhanced after the second vaccination compared to the first vaccination and compared to control groups. Fourteen days after the bacterial infection, the splenomegaly and the number of bacteria in the spleen were evaluated. The result showed that both rFe/Mn SOD and positive control RB51 decreased the bacterial replication in the spleen and the splenomegaly compared to control groups. Altogether, these results suggested that rFe/Mn SOD could induce host immunity against B. abortus infection.
        4,000원
        535.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 국내 플라워숍에서 절화의 판매가격표시제도를 활용하는 것에 대한 소비자와 판매자의 인식 및 만족도를 알 아보고 국내 화훼시장에서의 효과적인 판매가격표시제도의 활용방안을 모색하고자 국내 소비자 237명, 판매자 32명을 대상으로 설문을 진행하였다. 소비자와 판매자 모두 절화의 가격이 절화 상품의 포장법과 함께 가장 높은 구매 결정 요인 으로 나타났다. 플라워숍의 절화 판매가격표시제도 활용 장점 에 대해 소비자가 판매자보다 높게 인식하고 있었으며, 소비 자와 판매자 모두 판매가격표시제도를 활용함으로써 소비자 의 합리적인 절화 소비 및 절화 가격 신뢰에 가장 큰 도움을 준다고 응답하였다. 소비자는 절화 판매가격표시제도에 대한 불편한 점이 모두 보통(3.00) 이하로 나온 것에 비해, 판매자 의 경우 매번 바뀌는 가격(4.25) 및 가격 표기 기준의 애매함 (3.78), 가격 표기의 번거로움(3.69)을 불편한 요인으로 인식 하였다. 효과적인 판매가격표시제도 방법에 대한 설문에서 소 비자는 한 송이, 한 단 보다는 3~4줄기의 한 묶음씩 판매를 선호하였고, 판매자는 판매 단위에 따른 선호 차이가 없었다. 가격 표시 방법에는 소비자와 판매자 모두 화병에 가격을 표 시하는 것을 가장 선호하였다. 전반적인 절화 판매가격표시제 도에 대하여 소비자들은 판매자들이 기대하는 이상으로 만족 도가 높았으며(P<0.001), 특히 절화 품질(3.75)보다도 절화 가격(3.97)에 대한 만족도가 더 높아지는 것으로 나타났다. 이 를 통해, 절화 판매가격표시제도가 활성화된다면 소비자들의 절화 가격에 대한 신뢰도와 만족도를 높여줄 것이며 국내 화 훼산업 활성화에 도움이 될 것으로 판단한다.
        4,000원
        536.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Human can rapidly detect and deal with dangerous elements in their environment, and they generally manifest as attentional bias toward threat. Past studies have reported that this attentional bias is affected by anxiety level. Other studies, however, have argued that children and adolescents show attentional bias to threatening stimuli, regardless of their anxiety levels. Few studies directly have compared the two age groups in terms of attentional bias to threat, and furthermore, most previous studies have focused on attentional capture and the early stages of attention, without investigating further attentional holding by the stimuli. In this study, we investigated both attentional bias patterns (attentional capture and holding) with respect to negative emotional stimulus in neurotypical adults and adolescents. The effects of anxiety level on attentional bias were also examined. The results obtained for adult participants showed that abrupt onset of a distractor delayed attentional capture to the target, regardless of distractor type (angry or neutral faces), while it had no effect on attention holding. In adolescents, on the other hand, only the angry face distractor resulted in longer reaction time for detecting a target. Regarding anxiety, state anxiety revealed a significant positive correlation with attentional capture to a face distractor in adult participants but not in adolescents. Overall, this is the first study to investigate developmental tendencies of attentional bias to negative facial emotion in both adults and adolescents, providing novel evidence on attentional bias to threats at different ages. Our results can be applied to understanding the attentional mechanisms in people with emotion-related developmental disorders, as well as typical development.
        4,300원
        538.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 코로나19의 상황에서 대학생을 대상으로 스마트폰을 포함한 디지털기기의 사용이 눈과 근육뼈대계 통증에 미치는 영향을 알아보고자 하였다. 방법: 2022년 11월 온라인 설문조사에 응답한 대학생 156명의 자료를 분석하였다. 설문은 대상자의 일반적 특성을 포함하여 코로나19 대유행 동안 디지털기기의 사용시간과 종류, 컴퓨터시각증후군(computer vision syndrome, CVS) 16항목, 그리고 근육뼈대계 관련 11문항으로 구성하였다. CVS의 빈도는 0~2점, 강도는 1~2점으로 평가하였고, 근육뼈대계 통증은 약한 증상, 경도, 그리고 심한 증상으로 구분하여 3점 척도로 평가하여 총점을 산출하였다. 결과: 일일 평균 디지털기기의 사용은 7.97±3.46시간으로 온라인 수업을 위해 노트북(47.4%), 태블릿(33.3%), 데스크톱(12.2%), 그리고 스마트폰(7.1%)을 사용하였다. 매일 규칙적으로 운동하는 경우는 대상자의 22.4% 이었다. 컴퓨터시각증후군 관련 증상은 건조감이 가장 높은 점수를 보였고, 근육뼈대계 항목은 목 통증이 가장 심했다. 디지털기 기의 사용시간이 증가할수록 몸통(목, 등, 허리)과 전체 근육뼈대 통증이 심해졌고, 노트북이나 스마트폰을 이용해서 온라인 수업을 듣는 경우에는 데스크톱을 사용하는 경우와 비교해 상지통증 점수가 높게 나타났다. 매일 규칙적인 운동을 하는 경우에는 하지 않는 경우에 비해 컴퓨터시각증후군과 근육뼈대 통증의 통증이 작았다. 결론 : 디지털기기의 장시간 사용과 온라인 수업 동안에 사용하는 기기의 종류는 눈과 근육뼈대계 통증에 영향 을 미쳤다. 본 연구결과를 통해 이러한 환경에서 향후 눈과 근육뼈대계의 융합적인 연구와 관리가 함께 필요함을 알 수 있었다.
        4,300원
        539.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Global concerns have grown regarding emerging infectious diseases (EIDs) caused by previously unknown pathogens. Considering that strengthening surveillance capacity for unknown diseases is one of the core capacities for preparedness and early response to EIDs, identifying areas with poor capacity could be beneficial to prioritize regions for the improvement of surveillance. In this regard, we aimed to develop prediction models to identify high risk areas for low surveillance capacity for unknown diseases in a global scale. Unexplained death events reported between 2015 and 2019 were collected from two internet-based surveillance systems, ProMED-mail and Global Public Health Intelligence Network. From the reports, the number of reported unexplained deaths at the first report and the time gap between death and report were extracted as measures for sensitivity and timeliness of surveillance capacity, respectively. Using geographical locations of the reports and published global scale spatial data, including demographic, socioeconomic, public health and geographical variables, we fitted two boosted regression tree models to predict regions with the low sensitivity and timeliness. The performance of prediction model for the low sensitivity showed moderate validity, but in terms of the model for timeliness, the performance was unreliable. Therefore, we provided predicted risk only for low sensitivity. The mean predicted risks of low sensitivity were, respectively, 45.2%, 37.4%, 12.5%, and 3.0% in low-income, lower middle-income, upper middle-income, and high-income countries. Enhancing surveillance capacity in low-income countries is highly required, given the predicted low level of sensitivity despite the importance of early response.
        4,200원
        540.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper addresses the maintenance optimization problem in multi-component systems in which parts are connected in series, carrying out several missions interspersed with scheduled finite breaks. Due to limited time or resources, maintenance actions can be only carried out on a limited set of components. The decision maker then has to decide which components to maintain to ensure a pre-specified performance level during next mission. Most of the existing models in the literature usually assume only one system and enough spare parts. However, there are situations in which maintenance is required for multiple systems of the same type. To overcome this restrictive assumption, this study optimizes the maintenance problem considering the lack of repair parts and cannibalism for many identical systems. This study presents two optimization models with different objectives to solve the problem and analyzes the results so that the decision maker can decide. The results of this study are expected to be used for the maintenance of multiple systems of the same type, such as swarm drones.
        4,300원