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        검색결과 69

        41.
        2018.05 구독 인증기관·개인회원 무료
        Roller Compacted Concrete Pavement (RCCP) is placed by roller compaction of a mixture of less cement and unit water content and more aggregates and provides excellent early strength development with the help of interlocking of aggregates and hydration. The unit cement content of RCC pavements accounts for 85% of conventional pavements, with low drying shrinkage. As low drying shrinkage leads to smaller crack widths than ordinary concrete, RCC pavements can help elevate reflecting crack resistance if applied to a base layer of a composite pavement system. In a composite pavement with an asphalt surface laid over a concrete base, pavement temperature change is important in predicting pavement performance. As movement of the lower concrete layer is determined by temperature depending on pavement depth, temperature data of the pavement structure serves as an important parameter to prevent and control reflecting crack. Among the causes of reflecting crack, horizontal behavior of the lower concrete layer and curling-caused vertical behavior of joints/cracks are considered closely related to temperature change characteristics of the lower concrete course (Baek, 2010). Previous studies at home and abroad about reflecting crack have focused on pavement behavior depending on daily and yearly in-service temperature changes of a composite pavement (Manuel, 2005). Until now, however, studies have not been conducted on initial temperature characteristics of concrete in composite pavements where asphalt surface is placed over an RCC base. Annual temperature changes of in-service concrete pavements go up to 60 ℃, and those of asphalt overlays become around the twice at 110 ℃. This study evaluated initial crack behavior of composite pavement by investigating pavement temperature by depth of an RCC base and analyzing joint movement depending on change to temperatures of continuously jointed pavements. Findings from the study suggest that in composite pavements and asphalt overlays, time of laying asphalt has an important impact on crack behavior and reflecting crack.
        42.
        2018.04 구독 인증기관·개인회원 무료
        Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae) in forest is considered as a serious forest pest in pine trees. In this study, we collected entomopathogenic fungi from soil and assessed their virulence against the adults of the inset using a spray method in laboratory condition. Two entomopathogeinc fungi isolates showed high virulence against the adults. In the concentration of 1.0 × 107conidia/ml, the mortality rate of the adults were 53% and 60%. In semi-field condition, one isolate showed a virulence of 60% against the adult. Consequently, we confirmed the possibility of the fungal isolates in controlling the beetles. In near the future, we will investigate several factors which is possibly related to the control of the forest insect pest using entomopathogenic fungi in field conditions, given the importance of fungal formulation and practical application methods.
        43.
        2018.04 구독 인증기관·개인회원 무료
        The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopenia syndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest. Therefore, this study provides a screening method to select entomopathogenic fungi, having high virulence against H. longicornis. The virulence test was conducted by dipping method with a conidial suspension (1×107 conidia/ml). As a result, cadavers of H. longicornis infected with entomopathogenic fungi were obtained by this method. Based on this results, we selected several isolates having high virulence to H. longicornis. We suggest that, selected isolates in this study can be used for the control of H. longicornis.
        44.
        2018.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi have been known as promising candidates for biological control of insect pests. Recently, researchers consider the fungal thermotolerance in formulations and field applications. In this study, we investigated the production of thermotolerant Isaria javanica and I.fumosorosea conidia through grain-based solid cultures and exposure to light stress. As results, of the ten grain substrates, Italian millet, rice, perilla seed and sesame, rice, sorghum produced highly thermotolerant conidia in the strains. The two strains were exposed to a light stress and a heat stress. And they showed enhanced thermal stability compared to control, when exposed to 45°C for 2 hours. This work suggests that heat-resistant entomopathogenic fungal conidia can be produced by grain-based solid cultures and exposure to light stress.
        45.
        2018.04 구독 인증기관·개인회원 무료
        Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) is a serious insect pest of various crops in the world. The management of this pest mainly have relied on chemical agents. However, the overuse of chemical agents for long times causes insect resistance, and negative effects on environment. Therefore, alternative control methods, such as biological control, that are less harmful to the environment and have different mode of action are needed to control this pest. In this study, we isolated entomopathogenic fungi from Korean soil, and characterized them via morphological and molecular identifications and pathogenicity check against Tenebrio molitor larvae. The isolated fungi were subjected to virulence assay against T. Palmi with a conidial suspension of 1×107 conidia/ml in laboratory conditions. This entomopathogenic fungi library would be a good resource to select effective strains for the control of T. palmi in fields.
        46.
        2018.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi play an important natural role in regulating their insect host populations, and their ecology was also associated with plant and soil. These microorganisms have been living by reacting to insect, plant and environmental factor. The advanced bioinformatics technology such as next-generation sequencing and RNA sequencing has revolutionized in understanding of entomopathogenic fungi. Recently studies provided a lot of information on evolutionary relationships and virulence-related characteristics. We are starting to know where these microorganisms from is, and how they live in nature. The bioinformatics technology will give us further our understanding of the natural roles of these fungi in nature.
        47.
        2017.10 구독 인증기관·개인회원 무료
        The entomopathogneic fungal colonization has become an interesting issue in ecological pest management. Plant-orientedfungi induce plant growth promotion and act as natural control agents against insect pest. Herein this work, we evaluatedthe ability of fungal colonization on bark, branches and leaves of pine tree (Pinus densiflora) to select optimal candidatesfor controlling Japanese pine sawyer (Monochamus alternatus), which is the pine wilt disease vector in Korea. As a result,some Beauveria and Metarhizium isolates could colonize on the substrates of P. densiflora and showed pathogenicity againstM. alternatus. This result suggests that the selected entomopathogenic fungi are possibly candidates for long-term managementof M. alternatus in pine tree forest.
        48.
        2017.10 구독 인증기관·개인회원 무료
        Japanese pine sawyer, Monochamus alternatus HOPE (Coleoptera: Cerambycidae) are considered as important pine forestinsect pests in several countries which transmits the pine wood nematode, Bursaphelenchus xylophylus. In this study, wetried to control Japanese pine sawyer using entomopathogenic fungi to prevent the spread of pine wilt disease in Korea.Several entomopathogenic fungi were exposed to the adults of Japanese pine sawyer and mycosis was observed in themembranous cuticles after 6 days. In particular, two isolates showed high virulence against the adults. The selected 2isolates were sprayed to the adults at 1×105, 1×106 and 1×107 conidia/ml. In the concentration of 1×107 conidia/ml, thesurvival rates of insects were 40% and 47%, respectively. Based on these results, the possibility of controlling the Japanesepine sawyer was confirmed.
        49.
        2017.10 구독 인증기관·개인회원 무료
        Chemical pesticides have been used for persimmon pest control, however the overuse caused insect resistance andenvironmental toxicity. Herein this work, we investigated the biological potential of eco-friendly organic pesticides (biologicals)and entomopathogenic fungi in controlling persimmon pests, Stathmopoda masinisaa and Riptortus pedetris. A botanicalmixture of Chinese scholar tree, goosefoot and subtripinnata extract, Bacillus thuringesis NT0423 and one isolate of Beauveriabassiana showed high insecticidal activity against the pests in laboratory conditions. The selected botanical extract andmicroorganism were combined with a chemical pesticide (buprofezin+dinotefuran WP) and were assessed their controlefficacy in persimmon fields. Compared to the three times of chemical spray, the combination of more than one timeof chemical spray and the selected biologicals controlled the persimmon pests with an acceptable levels. Consequentlyone time of biological spray can be integrated to the spray program where only chemicals are strongly considered.
        50.
        2017.10 구독 인증기관·개인회원 무료
        The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopeniasyndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest.We evaluated three bioassay methods, such as spray, dipping and dropping. As a result, the dipping method was themost efficient way to measure the fungal virulence. Finally, we constructed a Haemaphysalis longicornis pathogenic fungallibrary to further facilitate the resources to be used as potential biological control agents. A conidial suspension of 1×107conidia/ml was exposed to the ticks by dipping. We confirmed that some isolates were highly virulent to the ticks. Thisresults indicated that some fungi could be used to effectively control the Haemaphysalis longicornis.
        52.
        2013.04 구독 인증기관·개인회원 무료
        Mealworms, Tenebrio molitor (L.) is used as an important animal feed additive for growth promotion and health management, but potentially exposes to fungal infection. In this work, virulence of two species of entomopathogenic fungi against the insect, and the relationship between abiotic features and virulence were investigated. Secondly our consideration was also given to the effect of chemical fungicides on conidial germination for risk control. Between Beauveria bassiana (Bb) and Metarhizium roberstii (Mr) (previously M. anisopliae), Bb isolates had much higher virulence (~100% mortality in 3~4 days after the treatment), rather than Mr isolates in laboratory assays. Next, fungus-treated mealworms were kept at wheat bran at 20, 25, 30 and 35℃ with 3, 6, 9 times of water spray to the feeds for set-up of different humidity conditions. Inoculation of fungi to mealworms was conducted by fungal spray and feeding methods, which resulted in higher virulence in feeding method. In the feeding method, all temperature treatments except 35℃ showed high virulence against mealworms, but any significant relationship between virulence and humidity was not observed. In the chemical fungicide screening, fluazinam (CAS No. 79622-59-6) and mancozeb (8018-01-7) significantly inhibited the germination of Bb and Mr conidia. This work suggest that contamination of wheat bran with fungal pathogens, particularly B. bassiana may induce mycosis of mealworms, but introduction of effective fungicides possibly reduce fungal infection.
        53.
        2008.05 구독 인증기관·개인회원 무료
        Temperature-dependent development and oviposition component models were developed for Pseudococcus cryptus Hempel (Homoptera: Pseudococcidae). Egg development times decreased with increasing temperature and ranged from 2.4d at 16℃ to 1.0d at 28℃. Total development times of nymphs reared on citrus leaves decreased from 54.9d at 16℃ to 17.4d at 28℃ and 19.3d at 32℃. As P. cryptus showed an ovoviviparous reproductive behavior, the periods of egg and the 1st nymph were combined. By fitting linear models to the data the lower developmental threshold temperatures for egg-1st nymphs, the 2nd nymphs, the 3rd nymphs, and all nymphs combined were calculated as 8.7, 12.8, 13.1, and 12.1℃, respectively. The thermal constants were 198.6, 84.7, 69.8, and 296.3 degree-days for each of the above stages. The non-linear model based on a Gaussian equation, which fits the relationship between development rate and temperature was well for all stages. Adult longevity decreased with increasing temperature and ranged from 80.4d at 16 to 31.3d at 32.0℃. Also, preoviposition and oviposition periods showed a similar pattern with the longevity. P. cryptus had a maximum fecundity of 111 eggs per female at 28℃, which declined to 102.7 eggs per female at 32℃.
        54.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        Interlellkin • 8(IL-8) is an important cytokine involved in tllmor growth and angiogenesis in a variety of malig nancies. bllt the regll lation of IL-8 in 01 외 cancer cells are llnderstood . We invesLigated whether mi togen-activated protein kinases pathway is involved in iron chelator-mediated lL-8 produdion in inunortalized and malignant oral keratinocytes. In this study we examined the role of p38 and extracellular signal- reglllated kinase• 1/2 in the expression of [L-8 by DFO. Incllbation of IHOK and HN12 cel ls with DF'O increased the expression of 11-8 mRNA. as well as the release of IL-8 protein. The signal transdllction study revealed that both p38 and ERK1/2 were significantly activated in response to DFO. Accord ingly. the selective inhibitors for both kinases‘ eit her a lone or combination. abolished DFO- induced lL-8 secretion. indicating an importance of MAP kinase pathway. Interestingly. however‘ inhibition of the p38 and ERK pathway more attenuated IL-8 secretion in IHOK than in HN12 cells. DFO induced NF-kB activation , suggesting a NF-kB- dependent mechanism in DFO- induced IL-8 production. In addition, p38 and ERK inhi bition resulted in the accelerated degradation of lL-8 mRNA, suggesting that in IHOK and HN12 cells, p38 and ERK cunLr iullLe Lo DFO imluced IL-8 secretion by IHOK and HN12 cells via a posttranscriptional mechanism that involves stabilization 01' the IL-8 transcript. Finally. we investigatecl llsing specific inhibitors : 8NP and G8NO for NO c1onor. PDTC for potent inhibitor of NF-kB. Cycloheximide for inhibition of de novo protein synthesis. We observecl 8NP ancl PD1'C clepenclent IL-8 gene incluction in IHOK cell s. but not in HN12 cells used specific inhibitors‘ Collectively. these results demonstrate that‘ targeting MAP kinase ancl NF-kB pathway may be a potentiaI approacb to controlling the angiogenes is ancl growth 이 human oral cancers
        55.
        2015.10 KCI 등재 서비스 종료(열람 제한)
        To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.
        56.
        2013.09 서비스 종료(열람 제한)
        We compared the results of early follow-up of F-18 FDG PET/CT and MRI performed within one month after radiation therapy for cervix cancer patients. We conducted a retrospective review of the clinical data of cervix cancer patients whose PET/CT and pelvic MRI performed at staging and within one month from the end of RTx. SUVmax on PET/CT and size on MRI of the primary tumor were analyzed. We compared %change of SUVmax and size between staging and follow-up. A total of 27 patients were enrolled. At staging, larger tumor showed high SUVmax. At follow-up, no significant correlation was observed between size and SUVmax. In 77.8% of patients, changes in SUVmax were well correlated with changes in size. No correlation was observed between % change and value at staging in both SUVmax and size. Except for six patients who showed significant FDG uptake without evidence of a mass on MRI, % changes of size and SUVmax were well correlated. Metabolic change can be accessible on early follow-up PET/CT at±1 month from the end of the RTx of cervix cancer. However, careful interpretation of PET/CT is needed due to possible radiation-induced hypermetabolism even without a definite mass on MRI.
        57.
        2013.06 서비스 종료(열람 제한)
        A 56 year-old women with a history of breast cancer underwent Tc-99m Hydroxymethylene Diphosphonate (HDP) bone scintigraphy at an annual follow-up, and abnormal focal uptake was observed in the right upper abdomen. However, subsequent single photon emission computed tomography/computed tomography (SPECT/CT) successfully delineated the uptake in a normal gallbladder. It was concluded that the abnormality had been caused by unusual Tc-99m HDP excretion and not by a metastatic lesion. Follow-up studies confirmed this diagnosis. This case demonstrates the usefulness of SPECT/CT in patients with unusual gallbladder uptake by bone scintigraphy.
        58.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        This study was to set the guidelines of soil chemical components in order to assure the safety and quality ofthe panax ginseng from physiological disorder. The disorder symptoms appeared on the leaf with yellow spot, atrophy, yel-low-brown spot, also showed red skin and rough skin of the root. Occurrence type of physiological disorder in cultivatedfield divided into two types:type I ‘such as, yellow spot’ consist of single disorder symptom; type II ‘such as, yellow spotand yellow-brown spot’ consist of two or more different disorder symptoms. The individual contribution of soil properties tothe occurrence type was as follows ; The yellow spot was affected by Na>NO3-N>salinity (EC) in soil. The same results wasobserved in red skin. Atrophy was affected by NO3-N>salinity (EC)>Ca>Mg. Rough skin was affected by P2O5>pH>Organic material > K. It showed positive associated to P2O5, pH and K, but negative associated to organic matter. Simulta-neous occurrence of two different disorder, including cases which yellow spot and yellow-brown spot, those were affected byNO3-N > salinity (EC) > Na > Mg. In the case of atrophy plus yellow-brown spot, those also were affected by in the order :NO3-N > salinity (EC) > Ca > Mg > Na. Red-rough skin was affected in the order : salinity (EC) > NO3-N > K > Na. Soilchemical components appear to be related to occurrence of physiological disorder, particularly in salinity (EC) and NO3-N.The salinity (EC) and NO3-N were negative related to plant growth. In addition, exchangeable cation capacity play criticalroles in attributing to complex occurrence of physiological disorder.
        59.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to identify soil physical characteristics as guideline for high yield potential inginseng cultivated field which produced 6 years root. Harvest yields of ginseng to be divided by parent rock was in order ofphyllite and red shale 3.1㎏/3.3㎡ > granite and gneiss·schist 3.0㎏ > basalt 2.6㎏ > porphyry 2.2㎏ in upland and forestsoil. Also, with classified by topography, it was in order of foot slope and alluvial fan 3.2㎏/3.3㎡ > valley 3.0㎏ > low hill2.9㎏ > hill, lave flow and dilluvial terrace 2.8㎏ in survey tilth. Class determination of soil texture, it was in order of sandyloam 3.1㎏/3.3㎡ > loam and silt loam 3.0㎏ > clay loam 2.9㎏ > silt clay loam 2.8㎏ in survey tilth. Slope condition offarming land, in case of sloping (2~7%), it was 3.1㎏/3.3㎡ but deep sloping (15~30%) caused decreasing harvest yield. Indrainage classes (excessively, well and moderately well), there was no significantly different in harvest yields. Relationshipbetween harvest yield and soil series, Production sites as yielding 3.0㎏/3.3㎡ were seven sites, also it was contained 14 soilseries. Production sites as yielding 2.5~3.0㎏/3.3㎡ were eleven sites, it was contained 16 soil series. Production sites asyielding 2.0~2.5㎏/3.3㎡ were 10 sites, it was contained 4 soil series.
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