검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 1,254

        741.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of high energy ball-milling (HEBM) on the sintering behavior and piezoelectric properties of 0.1 wt% doped 0.8Pb()-0.2Pb() (PMN-PZT) ceramics were investigated. It was found that HEBM treatment was quite effective to reduce the average particle size down to 300 nm, leading to increased density as well as enhanced piezoelectric properties of a sintered specimen even though prolonged HEBM resulted in unwanted secondary phases that caused a degradation of piezoelectric properties. The dielectric constant (), piezoelectric coupling factor () and piezoelectric constant of 0.1 wt% doped PMN-PZT ceramics prepared via HEBM for 10 h reached 2040, 0.68 and 554 pC/N, respectively.
        4,000원
        742.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of doping on the crystal structure, ferroelectric, and piezoelectric properties of (K,Na) (KNN) ceramics have been investigated. was found to be effective in enhancing the densification and grain growth during sintering. X-ray diffraction analysis indicated that Mn ions substituted B-site Nb ions up to 2 mol%, however, further doping induced unwanted secondary phases. In comparison with undoped KNN ceramics, the well developed microstructure and the substitution to B-sites in 2 mol% Mn-doped KNN ceramics resulted in significant improvements in both piezoelectric coupling coefficient and electromechanical quality factor.
        4,000원
        743.
        2010.10 구독 인증기관·개인회원 무료
        Large amounts of genetically modified (GM) grains, including maize, cotton and soybean, have been imported to Korea for food, feed and processing (FFP). To evaluatethe environmental impacts, particularly on non-target insects, of FFP GM grains of unknown source, it is a prerequisite to identify Cry protein types in the test GM grains and to establish proper risk assessment protocols. Imported GM maize grains were randomly obtained and their Cry toxins were analyzed by ELISA using Cry1A, Cry1F, and Cry3A antibodies. Since all tested GM maize grains contained Cry1A, Tenebrio molitor, a non-lepidopteran species, was selected as a non-target insect species. A domestic maize strain was used as a non-GM control, which did not show any differences in major nutritional composition from the GM maize grain. Slightly increased survival rate and head capsule width of T. molitor larvae were observed when reared on GM maize powder, demonstrating no sub-chronic adverse effects of GM maize on T. molitor larvae. Head capsule width of T. molitor neonate increased steadily from hatch to 70-day-old, regardless of being fed Bt or non-Bt maize. ELISA test using Cry1A-antibody revealed that concentration of Cry1A protein slowly increased in the whole body of T. molitor from 0 to 50 post-feeding days when the insects were fed GM maize but rapidly decreased within 5 days when Bt maize-fed larvae were transferred to non-Bt maize, showing that the Cry toxin is not accumulated inside the body of T. molitor once the exposure source is removed. In addition, no Cry protein was detected in the hemolymph of the larvae reared on Bt maize, suggesting little possibility of Cry toxin exposure to higher tropic level. Taken together, the imported GM-maize grains is not likely to cause any side impacts on non-target insect T. molitor.
        744.
        2010.10 구독 인증기관·개인회원 무료
        Pine wilt disease (PWD) represents a major threat to forest ecosystems worldwide. Although PWD is now better understood, effective control measures for this disease have still not been devised. Here, we report several years of field studies on preventative silvicultural control of PWD. Silvicultural control through preventative clear-cutting and the manual removal of logs was implemented between 2005 and 2009 in 16 Korean districts that had newly PWD-infected stands. Preventative clear-cutting of neighbouring asymptomatic pine trees (within a 10 to 50-m radius ofwilt trees) and the removal of felled logs or branches suppressed spread of PWD. Occurrences of PWD wilt pines in districts (city or county) subjected to this silvicultural control method were significantly reduced compared with those in districts using conventional controls (physical or chemical treatment of wilt pine trees). Through silvicultural control, PWD was successfully suppressed in 11 of 16 districts investigated. In contrast, successful control was achieved in only 1 among 18 districts subjected to conventional control. Our results will be of considerable interest to those engaged in the very difficult battle against the global spread of PWD.
        745.
        2010.10 구독 인증기관·개인회원 무료
        This study was conducted to investigate the altitudinal distribution of the ground beetle community in a mountain area during 2007 to 2009, and to examine what habitat characters are most relevant to the distribution of mountain ground beetle species, and finally to identify potential biological indicators for monitoring in forest. The study area was Mt. Sobaeksan National Park (1439 m elevation), in Punggi-up, Gyeongsangbuk-do, Korea. Ground beetles were collected by pitfall traps, which were installed along the altitudinal gradient 437, 757, 1100 and 1420 m. In total, 3,259 individuals were identified as 32 species in 18 genera. The dominant species were Synuchus cycloderus (29.4%), Eucarabus sternbergi sobaeksanensis (15.4%) and Pterostichus orientalis (9.7%) in order. Overall, the ground beetle community structure was different along the altitude (similarity 65.2%) by NMDS ordination, but also were clustered into 2 groups, 437 and 757 m, and 1100 and 1420 m (similarity 57.9%). Therefore, the ground beetle assemblage could provide basic information for forest management. In this study, some ground beetle species were suggested to potential biological indicators along altitudinal gradient.
        746.
        2010.10 구독 인증기관·개인회원 무료
        Scirtothrips dorsalis Hood is a newly advent pest on citrus in Jeju. Both larvae and adult attack the new shoots and young and matured fruits of citrus. S. dorsalis is highly polyphagous with over 100 recorded species, but not known in Jeju. As a result from investigating the host plants in and/or around citrus orchards in Jeju during 2009 to 2010, they were 25 families 39 species. The total thrips examined on those plants were 13 species, and the richness thrips among them was S. dorsalis, Frankliniella occidentalis, Thrips tabaci and Thrips hawaiiensis. The widespread host plants of S. dorsalis were Mallotus japonicus, Paederia scandens, Hedera rhombea, Cayratia japonica and Clematis apiifolia and they can be also used for monitoring plants. On early May, the larvae of S. dorsalis were first investigated on the shoots of Mallotus japonicus, Lonicera japonica, Paederia scandens, Viburnum awabukira, Fraxinus rhynchophylla and Celtis sinensis. The other thrips species except S. dorsalis and T. tabaci, especially F. intonsa, T. hawaiiensis, T. flavus and T. coloratus were just found on flower stalks during the blooming season.
        747.
        2010.10 구독 인증기관·개인회원 무료
        The EAG (Electroantennogram) has been used to find out chemical substance effective to insect. We tried to use EAG recording for catching of responsible acoustic signals to Lirimyza trifolii (Diptera: Agromizidae). In fly auditory organ known as Johnston's organ located on antenna. Pure tone sounds (sine wave) and courtship songs of several kinds of species were broadcasted to excised head of the fly. Significant EAG signals were detected when released the 20 Hz pure tone sound and long pulse train patterns, which were courtship songs of Cryptonevra inquilina and Lipara japonica (Chloropidae). For conformation of it's effectiveness, we further analyzed movement behavior with the signal got from the EAG recording. Information entropy could represent the specimens activities of movement tracks. The entropy with sound was relatively lower than without sound. The combination of EAG responding and behavioral observation would be useful to analyze the response of insect pest against acoustic signals and develop acoustic pest managing tool in agriculture.
        748.
        2010.10 구독 인증기관·개인회원 무료
        The oral toxicities of symbiotic bacteria Photorhabdus temperata ssp temperata (Ptt), mutually associated with entomopathogenic nematode Heterorhabditis megidis, and P. luminescens ssp. laumondii (TT01) with H. bacteriophora, were demonstrated to adults of the sweetpotato whitefly Bemisia tabaci. Sucrose solution (25%) containing bacteria-free supernatant of culture media of symbiotic bacteria was ingested into adult whiteflies within the glass tube. Whitefly mortalities were shown similar patterns against two bacterial media. Mortalities were significantly increased to 60-64% at 36 hours and almost 100% at 60 hours after treatments. In addition, We demonstrated the effect of oral ingestion of symbiont culture media on the gene expression of B. tabaci. Several genes fluctuated those expression levels. Our results suggest that oral ingestion of symbiont culture media of entomopathogenic nematodes significantly changed metabolic rates and highly lethal to whiteflies. The use of symbiotic bacteria of entomopathogenic nematodes provides a great potential as an alternative genetic resource of Bacillus thuringiensis, a major resource of microbial insecticide.
        749.
        2010.10 구독 인증기관·개인회원 무료
        The sweetpotato whitefly, Bemisia tabaci, is a vector insect of more than 100 plant-diseased viruses as well as a serious pest of various horticultural crops. B. tabaci is a species-complex that consists of at least 24 biotypes, which show different biological characteristics including host range, fecundity, insecticide resistance and virus transmission. Here we identified biotype, endosymbiotic bacteria, and tomato yellow leaf curl virus (TYLCV) acquisition of various B. tabaci populations collected in Korea. In addition, we compared those profiles with B. tabaci collected from Bangladesh and Myanmar, and the greenhouse whitefly, Trialeurodes vaporariorum. PCR diagnosis of cytochrome oxidase I (COI) showed that all B. tabaci populations of Korea were Q-biotype and closely related with a subgroup I (MedBasin 1), which is indigenous to the Western Mediterranean area. Ribosomal DNA analysis of 5 endosymbionts showed that both Cardinium and Hamiltonella were detected in most tested populations while the presence of Arsenophonus, Fritschea and Wolbachia dependent on populations. Our results suggest that the acquisition of TYLCV do not related with the endosymbiont profile of B. tabaci.
        750.
        2010.10 구독 인증기관·개인회원 무료
        Spider mites are one of major pests in cultivations of various ornamental plants and also important in plant quarantine service. Due to the very small body size and high similarity within the Genus the identification of species is difficult even at the microscopic observation. To identify 5 major species (Tetranychus cinnabarinus, T. urticae, T. phaselus, T. kanzawai and T. truncatus) in the Genus Tetranychus at the molecular level, we designed 4 species-specific primer sets using nucleotide sequences of the internal transcribed spacer (ITS2) region in the nuclear ribosomal repeat unit. At the PCR diagnosis of extracted genomic DNAs of 5 species using each primer set, specific primers of both T. phaselus and T. truncates were species-specific to their own species samples. However, specific primer set of T. urticae detected T. cinnabarinus as well as T. urticae. Specific primer set of T. kanzawai detected T. truncates as well as T. kanzawai, even though detection intensities were lower in non-target species.
        751.
        2010.10 구독 인증기관·개인회원 무료
        Due to the very small body size of spider mite, it is difficult to prepare DNA extraction simultaneously with slide samples from a single individual. Here we developed non-mashed DNA extraction method from a single spider mite to apply for molecular as well as morphological identification. Total genomic DNA was isolated from a single female adult using Genomic DNA extraction kit without the sample homogenization. DNA content of a single spider mite was 60-90 ng, which is sufficient for the PCR analysis. However, the quantity of extracted DNA and quality of the cuticle sample were dependent on the incubation time into the lysis buffer. Our results suggest that non-mashed DNA extraction method would be useful for the identification of very small mites as well as insects at the levels of DNA and morphology.
        752.
        2010.10 구독 인증기관·개인회원 무료
        Aphids (Hemiptera: Aphididae) are well known as micro-insect pests, which are very specific to their host plants, sucking phloem for acquiring nutrients, and most of them have successfully maintained parthenogenetic generations cyclically or permanently. In the world, the approximately 5,000 described aphid species belong to the family Aphididae, which has taxonomically been subdivided into 27 subfamilies in current. In recent, we have revised the checklist of the Korean aphids based on 43 references which include the catalogues, checklists, faunistic researches, and taxonomic reports treating the aphids in the Korean Peninsula. As results, we confirmed that a total of 427 valid species (species names) in 142 genera in 16 subfamilies had been historically recognized in the Korean Peninsula after checking classifications and invalid names (misidentifications, synonyms, and etc.). Among them, 36 species need Korean name which mostly were recorded after 2000. We also present and correct the wrong applications of some invalid names still used in official internet databases and documents due to citation of 'Checklist of Insects from Korea (Anonymous, 1994)'.
        753.
        2010.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        레이저 용발법에 의한 금속 표면 제염특성을 평가하였다. 레이저로는 파장 532 nm, 펄스에너지 150 mJ, 펄스폭 5 ns의 큐스위치 Nd:YAG 를 적용하였고, 금속 표면에 CsNO3, Co(NH4)2(SO4)2, Eu2O3 그리고 CeO2를 오염시켜 이들의 제염 특성을 평가하였다. 제염 변수로는 레이저 적용횟수, 레이저 에너지 밀도 및 레이저 조사 각도 특성을 평가하였으며 각각 8, 13.3 J/cm2 및 30o의 최적 조건을 확인하였다. 제염 효율은 오염성분의 비점과 관련이 있었으며 CsNO3>Co(NH4)2(SO4)2>Eu2O3>CeO2 순이었다. 또한 여러 에너지 밀도 조건에서 스테인레스 스틸 재질의 식각 깊이 제어 특성을 규명하였다.
        4,000원
        754.
        2010.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The research discussed in this paper was conducted to evaluate an intensive English teacher training program (IETTP) and to consider implications for in-service English teacher education. Data was gathered from a variety of sources including trainees’ self-evaluation of their teaching and English language proficiency, feedback on sessions of the program, interviews, and documents. The analysis of the gathered data revealed that the trainees perceived their teaching improved. The comparison of the pre- and post-tests of language skills showed that the level of the trainees’ English language significantly improved. The trainees’ feedback on the program and the trainers revealed that they were satisfied with the course components, and with the trainers’ enthusiasm, materials, motivation and demonstrations. It was also found that the program management was process-focused; the evaluation was conducted on a regular basis and the results were fed back into the program. The findings of the program evaluation supported the conclusion that the trainees benefitted from the programs and that the goals of the training program were achieved at a satisfactory level in most areas. The findings provide guidelines for the further development of IETTPs, and implications for policy-making on English teacher education.
        8,600원
        755.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Boron doped fullerene C60 (B:C60) films were prepared by the thermal evaporation of C60 powder using argon plasma treatment. The morphology and structural characteristics of the thin films were investigated by scanning electron microscope (SEM), Fourier transform infra-red spectroscopy (FTIR) and x-ray photo electron spectroscopy (XPS). The electrochemical application of the boron doped fullerene film as a coating layer for silicon anodes in lithium ion batteries was also investigated. Cyclic voltammetry (CV) measurements were applied to the B:C60 coated silicon electrodes at a scan rate of 0.05 mVs-1. The CV results show that the B:C60 coating layer act as a passivation layer with respect to the insertion and extraction of lithium ions into the silicon film electrode.
        3,000원
        756.
        2010.06 구독 인증기관 무료, 개인회원 유료
        Functional regulation of a specific tissue or organ is controlled by a number of ways, including local cell‐gcell interaction. Of several forms of cell‐gcell junctional complexes, gap junctions are caught a great attention due to a formation of direct linkage between neighboring cells. Gap junctions are consisted of connexin (Cx) isoforms. In the present study, we evaluated expressional profiling of Cx isoforms in the rat initial segment (IS) of the male reproductive tract at different postnatal ages. The presence and expression of 13 Cx isoform mRNAs were determined by semi‐gquantitative real‐gtime PCR analyses. A total of 8 Cx isoform mRNAs were detected in the IS of the male rats during postnatal development. The highest level of Cx30.3 mRNA was found at 5 months of age, while abundance of Cx31 mRNA was the highest at 1 year of age. Expression of Cx31.1 gene was relatively consistent during the postnatal development. Fluctuation of Cx32 and 37 gene expression was observed during the postnatal period. Significant elevation of Cx40 mRNA abundance was detected at 25 days of age and older ages. Expression patterns of Cx43 and 45 genes were similar with the highest level at 2 weeks of age, followed by gradual decreases at older ages. These results indicate differential regulation on expression of Cx isoforms in the rat IS during postnatal development. A complicated regulation of gene expression of Cx isoforms in the IS at different postnatal ages is suggested.
        4,000원
        757.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        Methanol and hot water extracts of Daedalea bien-nis were investigated for its antioxidant activity, poly- phenol content and tyrosinase inhibitory effect. The antioxidant activity was evaluated using 1, 1-diphenyl -2-picrylhydrazyl (DPPH) scavenging assay. The antioxidant activities of hot water and 80% methanol extracts of Daedalea biennis fruiting body were 52.06%. and 92.62% at 1.5mg/ml concentration. Total polyphenol content of hot water and 80% methanol extracts were 12.26㎍ GAEs/mg and 13.69㎍ GAEs/mg. Tyrosinase inhibitory activity of water extract was 19.70% while 80% methanol extract was 15.75% at 1mg/ml concentration.
        758.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        Methanol and hot water extracts of Suillus granulatus were investigated for its antioxidant activity, polyphenol content and tyrosinase inhibitory effect. The antioxidant activity was evaluated using 1, 1- dipheny l-2-picrylhydrazyl (DPPH) scavenging assay. The antioxidant activities of hot water and 80% methanol extracts of Suillus granulatus fruiting body were 51.49%. and 90.58% at 1.5mg/ml concentration. Total polyphenol content of hot water and 80% methanol extracts were 33.21㎍ GAEs/mg and 27.97㎍ GAEs/mg. Tyrosinase inhibitory activity of water extract was 7.8% while 80% methanol extract was 20.88% at 1mg/ml concentration.
        759.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        This study was carried out to obtain new anti-gout agent from mushrooms. Various extracts from twelve kinds of mushrooms were prepared by water and ethanol extractions and its anti-gout xanthine oxidase inhibitory activity were investigated. Water extract of Flammulina velutipes and Agaricus bisporus fruiting bodies showed high xanthine oxidase inhibitory activity of 70.8% and 60.0%, respectively. However, its inhibitory activity of these ethanol extracts were very low excepet 60.3% of Innotus obliquus. Finally, we selected Flammulina velutipes, showing the highest xanthine oxidase inhibitory activity as a producer of new anti-gout agent.
        760.
        2010.06 구독 인증기관 무료, 개인회원 유료
        Selenoprotein S (SelS) is widely expressed in diverse tissues where it localizes in the plasma membrane and endoplasmic reticulum. We studied the potential function of SelS in erythrocyte differentiation using K562 cells stably over-expressing SelS wild-type (WT) or one of two SelS point mutants, U188S or U188C. We found that in the K562 cells treated with 1μM Ara-C, SelS gradually declined over five days of treatment. On day 4, intracellular ROS levels were higher in cells expressing SelS-WT than in those expressing a SelS mutant. Moreover, the cell cycle patterns in cells expressing SelS-WT or U188C were similar to the controls. The expression and activation of SIRT1 were also reduced during K562 differentiation. Cells expressing SelS-WT showed elevated SIRT1 expression and activation (phosphorylation), as well as higher levels of FoxO3a expression. SIRT1 activation was diminished slightly in cells expressing SelS-WT after treatment with the ROS scavenger NAC (12 mM), but not in those expressing a SelS mutant. After four days of Ara-C treatment, SelS-WT-expressing cells showed elevated transcription of β-globin, y-globin, ε-globin, GATA-1 and zfpm-1, whereas cells expressing a SelS mutant did not. These results suggest that the suppression of SelS acts as a trigger for proerythrocyte differentiation via the ROS-mediated downregulation of SIRT1.
        4,000원