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        검색결과 1,442

        481.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Perennial need for bactericides requires cost-effective nanomaterials with strong antibacterial activities even in the absence of external irradiation. Hence, in this work, we have synthesized f-CFT (fluorinated TiO2- doped, glycine-functionalized MWCNTs) and have studied its antibacterial activities. Both gram-negative and gram-positive bacteria were analyzed in the absence of photo-activation. Zone of inhibition of 15 mm for S. aureus, and 11 mm for P. aeruginosa was observed for f-CFT owing to the synergistic bactericidal properties of functionalized MWCNTs, fluorine and nano-TiO2. Anatase phase TiO2 with average crystallite size as 35 nm was observed in XRD. Scanning electron microscopic images showed uniform mixed cubic structures. Hydroxyl groups observed in FT-IR along with the glycine MWCNTs interface aid the inhibition of bacterial growth even in the absence of photo activation. A desired higher gram-positive bacterial inhibition opens new gates for better antibacterial agents.
        3,000원
        482.
        2019.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with high probabilities of hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes of SN progenitor systems through the detection of the shock-heated emission that lasts less than a few days after the SN explosion. To catch the signal, IMSNG utilizes a network of 0.5-m to 1-m class telescopes around the world and monitors the images of 60 nearby galaxies at distances D < 50 Mpc to a cadence as short as a few hours. The target galaxies are bright in near-ultraviolet (NUV) with MNUV < - 18.4 AB mag and have high probabilities of hosting SNe (0.06 SN yr-1 per galaxy). With this strategy, we expect to detect the early light curves of 3.4 SNe per year to a depth of R  19:5 mag, enabling us to detect the shock-heated emission from a progenitor star with a radius as small as 0.1 R . The accumulated data will be also useful for studying faint features around the target galaxies and other science projects. So far, 18 SNe have occurred in our target fi elds (16 in IMSNG galaxies) over 5 years, confi rming our SN rate estimate of 0.06 SN yr-1 per galaxy.
        4,200원
        483.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carboxylated multi-wall carbon nanotubes (MWCNTs-COOH) was functionalized with 3-amino-5-phenylpyrazole (MWCNTs- f) and characterized by FTIR, EDX, SEM, XRD and TGA. The MWCNTs-COOH and MWCNTs-f were used for the adsorption of Cd(II), Hg(II), and As(III) ions from aqueous solutions. Additionally, to study the influence of pH, adsorbent dose, and initial ions concentration on the adsorption process, the central composite design (CCD) was applied. The quadratic model was used for analysis of variance and indicated that adsorption of metal ions strongly depends on pH. Timedependent adsorption can be described by the pseudo-second-order kinetic model, and adsorption process was modeled by Langmuir isotherm for the adsorbents. Thermodynamic analysis showed that the adsorption of Cd(II), Hg(II) and As(III) ions were spontaneous and endothermic. Moreover, the competitive adsorption capacities of the heavy metal ions were slightly lower than noncompetitive ones. The same affinity order was observed under noncompetitive and competitive adsorption: As(III) > Cd(II) > Hg(II) in the case of MWCNTs-f. Desorption study revealed the favorable regeneration ability of adsorbents powders, even after three adsorption–desorption cycles.
        5,500원
        484.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to determine the effects of different soy protein concentrate (0, 15, 30, and 45%), defatted soy flour (0, 10, 20, and 30%), and wheat flour (10, 20, and 30%) contents replacing fish meal on physiochemical properties of extruded aquatic feed by using a twin screw extruder. The moisture content, barrel temperature, die diameter, and screw speed were adjusted to 45%, 137oC, 4 mm, and 250 rpm, respectively. With the higher amount of soy protein concentrate replacing fish meal, the expansion ratio, swelling ratio, and water stability increased significantly while specific length and water holding capacity decreased significantly. With the increasing defatted soy flour content, expansion ratio increased significantly, but specific length, water holding capacity and water stability decreased significantly. With increase in the wheat flour content, the specific length significantly decreased while the water stability significantly increased. In conclusion, aquatic feed quality was optimized in this study and could be used in the future.
        4,000원
        488.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of daily short-distance walking exercise on milk production and metabolic status of the lactating dairy cows was investigated. The experiment was conducted with 10 lactating dairy cows comprising 2 groups (5 dairy cows/group), which were walking activity and non-walking activity. The walking activity (WA) group lactating dairy cows walked outdoors for 1 km/d, and the non-walking activity (non-WA) lactating dairy cows were maintained within a cowshed from 18thApril to30th May. The activity volume of the neck was not significantly different between the groups, but the activity volume of the leg was higher in WA group compared with non-WA (p<0.05). The rectal temperature was higher in the WA group (38.6 ℃) compared with non-WA (38.2 ℃) (p<0.05). No significant differences in dietary NE intake, milk production and milk composition were found between the groups. The plasma cortisol concentration was higher in WA group (2.14 μg/dl) compared to non-WA (0.95 μg/dl) (p<0.05). However, plasma cortisol level of WA dairy cows was significantly decreased as compared with non-WA cows. On the contrary, the level of plasma melatonin was increased in WA cows than that of non-WA dairy cows. It may be interpreted as a change in physical fitness. From this study, we suggest that walking activity can be improved energy balance. Further investigation is needed to determine whether different combinations of distance, rate or doing in morning or afternoon will stimulate energy balance.
        4,000원
        489.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Zona pellucida (ZP), a primarily representative coat of mammalian egg and embryo, has an extremely heterogeneous morphology during different developmental stages. The objective of the present study was to compare the morphological changes of the ZP surface of immature, in vitro and in vivo matured canine oocytes by using scanning electron microscopy (SEM). Canine ovaries were collected from local veterinary hospitals to recover immature oocytes. The ovaries were sliced and the released cumulus oocyte complexes (COCs) were washed with TL-HEPES. The selected COCs were randomly divided into two groups, first group was processed immediately at immature state and the second group was processed 72 h after in vitro maturation, and compared with in vivo derived oocytes. Oocytes were fixed, critical point dried and examined under SEM. The diameters of oocyte and outer holes of the ZP were measured on a total of 249 oocytes; the results were analyzed using One-way ANOVA. Our results showed that, the diameter of immature oocytes significantly differed (p < 0.05) from that of in vivo matured oocytes (79.60 ± 0.77 μm vs. 101.46 ± 1.07 μm, respectively). Similarly, a significant difference (p < 0.05) in the diameters between those of in vitro and in vivo matured oocytes were found (79.51 ± 2.36 μm vs. 101.46 ± 1.07 μm, respectively). Moreover, the diameters of the outer holes of the ZP were significantly (p < 0.05) larger in in vivo matured (1.48 ± 0.42 μm) than in vitro matured for 72 and immature oocytes (1.10 ± 0.16 and 0.43 ± 0.12 μm, respectively). Taken together, these data indicates that the ZP surface is related to oocyte maturity in canine.
        4,000원
        491.
        2018.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Korean Native Pig (KNP) has a uniform black coat color, excellent meat quality, white colored fat, solid fat structure and good marbling. However, its growth performance is low, while the western origin Yorkshire pig has high growth performance. To take advantage of the unique performance of the two pig breeds, we raised crossbreeds (KNP × Yorkshire to make use of the heterotic effect. We then analyzed the liver transcriptome as it plays an important role in fat metabolism. We sampled at two stages: 10 weeks and at 26 weeks. The stages were chosen to correspond to the change in feeding system. A total of 16 pigs (8 from each stage) were sampled and RNA sequencing was performed. The reads were mapped to the reference genome and differential expression analysis was performed with edgeR package. A total of 324 genes were found to be significantly differentially expressed (|log2FC| > 1 & q < 0.01), out of which 180 genes were up-regulated and 144 genes were down-regulated. Principal Component Analysis (PCA) showed that the samples clustered according to stages. Functional annotation of significant DEGs (differentially expressed genes) showed that GO terms such as DNA replication, cell division, protein phosphorylation, regulation of signal transduction by p53 class mediator, ribosome, focal adhesion, DNA helicase activity, protein kinase activity etc. were enriched. KEGG pathway analysis showed that the DEGs functioned in cell cycle, Ras signaling pathway, p53 signaling pathway, MAPK signaling pathway etc. Twenty-nine transcripts were also part of the DEGs, these were predominantly Cys2His2-like fold group (C2H2) family of zinc fingers. A protein-protein interaction (PPI) network analysis showed that there were three highly interconnected clusters, suggesting an enrichment of genes with similar biological function. This study presents the first report of liver tissue specific gene regulation in a cross-bred Korean pig.
        4,000원
        492.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, an empirical relationship between the energy band gap of multi-walled carbon nanotubes (MWCNTs) and synthesis parameters in a chemical vapor deposition (CVD) reactor using factorial design of experiment was established. A bimetallic (Fe-Ni) catalyst supported on CaCO3 was synthesized via wet impregnation technique and used for MWCNT growth. The effects of synthesis parameters such as temperature, time, acetylene flow rate, and argon carrier gas flow rate on the MWCNTs energy gap, yield, and aspect ratio were investigated. The as-prepared supported bimetallic catalyst and the MWCNTs were characterized for their morphologies, microstructures, elemental composition, thermal profiles and surface areas by high-resolution scanning electron microscope, high resolution transmission electron microscope, energy dispersive X-ray spectroscopy, thermal gravimetry analysis and Brunauer-Emmett-Teller. A regression model was developed to establish the relationship between band gap energy, MWCNTs yield and aspect ratio. The results revealed that the optimum conditions to obtain high yield and quality MWCNTs of 159.9% were: temperature (700ºC), time (55 min), argon flow rate (230.37 mL min–1) and acetylene flow rate (150 mL min–1) respectively. The developed regression models demonstrated that the estimated values for the three response variables; energy gap, yield and aspect ratio, were 0.246 eV, 557.64 and 0.82. The regression models showed that the energy band gap, yield, and aspect ratio of the MWCNTs were largely influenced by the synthesis parameters and can be controlled in a CVD reactor.
        4,000원
        493.
        2018.12 구독 인증기관 무료, 개인회원 유료
        Bullying among secondary school students has become one of the most disturbing issues in Nigeria. A variety of bullying behaviour abounds with their attendant negative consequences. This study investigated students’ attitudes towards bullying, environments in which bullying takes place and the extent of their involvement in bullying behaviours. The sample comprised 592 senior secondary students in Owerri metropolis who completed the Attitude to Bullying Rating Scale (ABRS), Checklist on Environments of Bullying (CEB), and Involvement in Bullying Rating Scale (IBRS). The findings indicate that a majority of students (67.57%) exhibited an inappropriate attitude toward bullying. Bullying was found to be prevalent among senior secondary school students in Owerri. Of the total number of students, 57.43% were involved as victims, 68.92% were involved as bullies, while 74.66% were involved as bystanders On the nature of bullying, social bullying ranked highest (82.94%), followed by physical bullying (81.1%) and verbal bullying (64%). With regards to the environments where bullying occurs, the study found that bullying can take place anywhere in the school and outside the school, however, the prominent places include the classroom (without the teacher), school play grounds, corridors, toilet ends, school canteens and on the way home. While a greater number of the male students were involved in physical bullying, more females were involved in verbal bullying. It is recommended that anti-bullying campaign be mounted in the secondary schools.
        4,000원
        494.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Graphene is a single atomic layer of carbon atoms, and has exceptional electrical, mechanical, and optical characteristics. It has been broadly utilized in the fields of material science, physics, chemistry, device fabrication, information, and biology. In this review paper, we briefly investigate the ideas, structure, characteristics, and fabrication techniques for graphene applications in lithium ion batteries (LIBs). In LIBs, a constant three-dimensional (3D) conductive system can adequately enhance the transportation of electrons and ions of the electrode material. The use of 3D graphene and graphene-expansion electrode materials can significantly upgrade LIBs characteristics to give higher electric conductivity, greater capacity, and good stability. This review demonstrates several recent advances in graphenecontaining LIB electrode materials, and addresses probable trends into the future.
        4,000원
        495.
        2018.11 KCI 등재 구독 인증기관·개인회원 무료
        Illegal, unreported and unregulated fishing (IUUF) is a complex problem because IUUF perpetrators not only have fisheries management issues, but also commit other crimes. This phenomenon raises further academic analysis of crime in fisheries at domestic and international levels. Indonesia has experienced different events leading to addressing crimes related to fisheries, which initially came from IUUF practices. To achieve legal certainty, crimes in fisheries issues must be separated from IUUF because IUUF is a matter under the mandate of FAO and crime in fishery is under the mandate of UNODC. Many have mixed IUUF and crimes in fishery in one basket, making the matter confusing from legal and practical point of view. At the domestic level, there must be a regulatory framework recognizing the linkage between fisheries and criminal activities At the international level, meanwhile, there must be an international cooperation through existing frameworks such as Mutual Legal Assistance.