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        검색결과 113

        21.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES : In this study, microstructural components of crumb rubber modified asphalt (CRMA) binder were investigated using environmental scanning electron microscope (ESEM). To clearly understand the elemental composition of the CRMA binder, energy dispersive X-ray spectroscopy (EDX) was employed on the ESEM samples. METHODS: CRMA binders were produced using open blade mixers at 177℃ for 30 min. The binders were artificially aged through a series of accelerated aging processes. Sample preparation was done by making a mold shape on the glass slide. Thereafter, the morphology of the CRMA binder was observed using the ESEM coupled with the EDX. RESULTS : The images captured from the ESEM indicate that the unaged CRMA binder appears to have a single-phase continuous nonuniform structure after the addition of crumb rubber particles, whereas the artificially aged CRMA binder was observed to have two different phases. ESEM coupled with EDX shows detailed internal structure of the modified binders compared to other technologies (i.e., optical microscopy, atomic force microscopy, and conventional scanning electron microscope). CONCLUSIONS: The captured images resemble the internal structures such as the viscous properties of the unaged CRMA binder and the interaction between the rubber particles and the base binder at aged condition. ESEM is a powerful instrument and with the introduction of EDX, it provided more details of the network microstructure of the asphalt binder. ESEM coupled with EDX is recommended for use in future investigation of microstructure of asphalt binders.
        4,000원
        22.
        2016.04 구독 인증기관·개인회원 무료
        Seagrasses, sea flowering plants, comprise approximately 60 species globally and are often called ‘ecosystem engineers’ because they create their own habitats by modifying the surrounding environments, which provide coastal zones with a number of crucial ecosystem services. Zostera marina (the common name ‘eelgrass’) is one of the seagrass beds-forming species distributed widely in northern hemisphere including the Korean coast, which plays a pivotal role in ecosystem as a primary producer and a nursery habitat or refuge for other marine organisms. However, due to global climate change and anthropogenic activities such as reclamation and dredging, there has recently been a drastic decline in population sizes of Z. marina in Korea. In order to develop effective conservation and restoration management programs of Z. marina populations, it would be helpful to consider all biological aspects of this species such as genetic characteristics as well as ecological and physiological features. This study first provides information on genetic diversity and genetic structure of Jeju Island and Namhae populations of Z. marina, which will contribute to the establishment of appropriate conservation and restoration management plans for future persistence of this species. Using six microsatellite markers, we investigated the level of genetic diversity and genetic structure among 10 geographic populations of Z. marina inhabiting Jeju Island (Hamdeok, Tokki-seom, Sungsan, Woljeong, Ojo) and Namhae (Gamak bay, Jindong bay, Nampo, Anggang bay, Geoje) on the southern coast of Korea. The level of genetic diversity within Jeju populations (mean allelic richness [AR]: 1.57 ~ 3.09) was found to be significantly lower than Namhae populations (AR: 3.09 ~ 4.29) (Mann-Whitney U-test, P < 0.05). These findings suggest that effective population sizes (Ne) of Jeju populations are generally smaller than those of Namehae populations. Within Jeju Island, Hamdeok population had the smallest population size (coverage: 138 m2) and the lowest genetic diversity (AR: 1.57), while Ojo population had the largest population size (coverage: 275,736 m2) and the greatest level of genetic diversity (AR: 3.09). Hamdeok population showed evidence of genetic bottleneck. These results again suggest that Ne of Jeju populations is generally low (except Ojo population). Among Jeju populations, all pair-wise comparisons of FST values (i.e., degree of genetic differentiation) were highly significant (FST = 0.0612 ~ 0.7168, P < 0.001) despite Jeju populations that were geographically closely located, indicating that these local populations are genetically divergent, probably due to a lack of gene flow among the populations. The observed strong population structure was substantiated by evidence that five genetic clusters are most likely, based on population assignment test (STRUCTURE). The Mantel test showed a positive relationship between genetic distance (FST) and geographic distance (km) across all the populations sampled (R2 = 0.4118, P < 0.05), suggesting that our data follow Isolation By Distance (IBD) model. Woljeong population revealed the highest level of FST values compared to other populations within Jeju Island in IBD. STRUCTURE and factorial correspondence analysis (FCA) further showed that some Woljeong individuals included genotypes of Namhae populations. Population size of Woljeong (coverage: 310m2) was approximately 50 % smaller than that of Sungsan (coverage: 841m2); however, extent of its genetic diversity (AR: 2.39) was even higher than that of Sungsan population (AR: 1.77). We speculated that Woljeong population underwent a transplantation from Namhae populations with relatively higher level of genetic diversity. FST values within Namhae populations were relatively lower (compared to within Jeju Island) despite the populations that were geographically more distant. It means that level of gene flow is higher among Namhae populations than among Jeju populations. Z. marina is known to have different life histories by water depth. In subtidal zone (deep water depth) populations predominantly undertake sexual reproduction through seeds such as annual life history, whereas those of intertidal zone (shallow water depth) undertake both sexual and asexual reproductions through horizontal rhizomes i.e., perennial life history. STRUCTURE analysis showed no clear differences between shallow and deep populations at Namhae, but some FST values were statistically significantly different despite their low values. For Geoje population sampled in 2005, intertidal and subtidal populations were not significantly different (FST = 0.0045, P = 0.033), but these populations sampled in 2015 showed a significant difference (FST = 0.0328, P < 0.001). It means that genetic structure of Geoje has been changed over the 10 year period between shallow and deep populations. Overall, the Jeju and Namehae populations analyzed in the current study have relatively low levels of genetic diversity and distinct genetic compositions, which warns the message that this ecologically important species should be conserved separately in the local populations and with high priority. We propose that future conservation and restoration plans for seagrasses should consider genetic characteristics particularly because a close relationship between genetic diversity and ecological performance in marine species has been well documented.
        25.
        2015.10 구독 인증기관·개인회원 무료
        Ips acuminatus (Coleoptera: Curculionidae) is one of the potential pests of various species of pines. To investigate the effects of thinning on I. acuminatus and Stigmatium pilosellum (Coleoptera: Cleridae), known as a natural enemy of bark beetles, were examined in Korean pine (Pinus koraiensis) forest in Chuncheon, South Korea in 2014. Three study site were selected - two sites (western slope and southern slope) that thinning was conducted in early spring 2014 and a site without thinning within 5 years. I. acuminatus and S. pilosellum were collected every week or fortnightly using the 12-unit Lindgren multi-funnel traps with pheromone lure (Ipsdienol +50/-50 40mg, Ipsenol +50/-50 40mg) from May to early October. The densities of I. acuminatus, the dominant species of bark beetles, were maximum 8.4 ± 0.9 and 1.4 ± 0.4 individuals/trap/day at thinning site and non-thinning site, respectively. In case of S. pilosellum, the dominant species of Cleridae, its densities were 17.7 ± 2.4 and 2.6 ± 0.8 individuals/trap/day at thinning site and non-thinning site, respectively. I. acuminatus showed first emergence peak on June and second emergence peak on September, but S. pilosellum showed only one time emergence peak on June – the density of S. pilosellum increased along with the density of I. acuminatus (r = 0.66, p = 0.0365). Our results shows that thinning in Korean pine forest increases the densities of I. acuminatus and S. pilosellum, reflecting increase in their food resources available.
        26.
        2015.10 구독 인증기관·개인회원 무료
        The present issue of insect resistance and environmental toxicity of pesticides is triggering deep discussion about the pest management tactics, in which pest monitoring and control activity are mainly involved. Novel control agents, hopefully overcoming the present issues and problems, should be researched and commercially applied to the farm fields. With the monitoring-based research, additionally we have to focus on the control-based, particularly control agent-based research and application. Entomo- pathogenic fungi can used as one of the possible novel control agents once considerations are given to the control of soil- or water-dwelling pests. In our research group, the entomopathogenic fungal library has been constructed using the mealworm-based isolation system, which showed a variety of opportunities of their use in pest control. Important key production technologies including granular formulation have been developed to increase their industrialization. Some entomopathogenic fungal isolates showed high biological performance in the control of rice weevils, western flower thrips and Japanese bettles in field stands. To elucidate the fungal mode of action, a fungal transformation system using AtMT and gene identification tools were established. Recently a more deep study about the relationship between insect and entomopathogenic fungi is be investigated using RNA seq. We suggest that to make the entomopathogenic fungal products be applied to agricultural farm field, R&D of down-stream process should be seriously considered as the key step.
        29.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of stacking sequence on the flexural and fracture properties of carbon/basalt/epoxy hybrid composites was investigated. Two types of carbon/basalt/epoxy hybrid composites with a sandwich form were fabricated: basalt skin-carbon core (BSCC) composites and carbon skin-basalt core (CSBC) composites. Fracture tests were conducted and the fracture surfaces of the carbon/basalt/epoxy hybrid composites were then examined using scanning electron microscopy (SEM). The results showed that the flexural strength and flexural modulus of the CSBC specimen respectively were ~32% and ~245% greater than those of the BSCC specimen. However, the interlaminar fracture toughness of the CSBC specimen was ~10% smaller than that of the BSCC specimen. SEM results on the fracture surface showed that matrix cracking is a dominant fracture mechanism for the CSBC specimen while interfacial debonding between fibers and epoxy resin is a dominant fracture process for the BSCC specimen.
        3,000원
        30.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Muscle satellite cell (SC) is responsible for postnatal muscle growth, repair, and regeneration. Satellite cell is an im-portant source of multi-potent stem cell process and differentiation into adipogenic, myogenic, and osteoblastogenic. The objective of this study was to identify alter of transcriptome during differentiation in porcine satellite cell and to elevated transcriptome at different stages of postnatal development to gain insight into the differences in differ-entiated PSC. We used RNA-seq technique to investigate the transcriptomes during differentiation in pig muscle. Sequence reads were obtained from Illumina HiSeq2000. Differentially expressed genes (DEG) were detected by EdgeR. Gene ontology (GO) terms are powerful tool for unification among representation genes or products. In study of GO biological terms, functional annotation clustering involved in cell cycle, apoptosis, extracellular matrix, phosphoryla- tion, proteolysis, and cell signaling in differences stage. Taken together, these results would be contributed to a better understanding of muscle biology and processes underlying differentiation. Our results suggest that the source of DEGs could be better understanding of the mechanism of muscle differentiation and transdifferentiation.
        4,500원
        31.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Satellite cells were derived from muscular tissue in postnatal pig. Satellite cell is an important to growth and development in animal tissues or organs. However, the progress underlying induced differentiation is not clear. The aim of this study was to evaluate the morphologic and the transcriptome changes in porcine satellite cell (PSC) treated with insulin, rosiglitazone, or dexamethasone respectively. PSC was obtained from postnatal muscle tissue. In study 1, for study the effect of insulin and FBS on the differentiated satellite cells, cells were cultured at absence or presence of insulin treated with FBS. Total RNA was extracted for determining the expression levels of myo-genic PAX3, PAX7, Myf5, MyoD, and myogenin genes by real-time PCR. Myogenic genes decreased expression levels of mRNA in treated with insulin. In study 2, in order to clarify the relationship between rosiglitazone and lipid in differentiated satellite cells, we further examined the effect of FBS on lipid accumulation in the presence or absence of the rosiglitazone and lipid. Significant differences were observed between rosiglitazone and lipid by FBS. The mRNA of FABP4 and PPARγ increased in rosiglitazone treatment. In study 3, we examined the effect of dexame-thasone on osteogenic differentiation in PSC. The mRNA was increased osteoblasotgenic ALP and ON genes treated with dexamethasone in 2% FBS. Dexamethasone induces osteoblastogenesis in differentiated PSC. Taken together, in differentiated PSCs, FABP4 and PPARγ increased to rosiglitazone. Whereas, no differences to FBS and lipid. These results were not comparable with previous reports. Our results suggest that adipogenic, myogenic, and osteoblasto-genic could be isolated from porcine skeletal muscle, and identify culture conditions which optimize proliferation and differentiation formation of PSC.
        4,000원
        32.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Muscular satellite cell (SC), which is stem cell of postnatal pig, is an important for study of differentiation into adipogenesis, myogenesis, and osteoblastogenesis. In this study, we isolated and examined from pig muscle tissue to determine capacity in proliferate, differentiate, and expression of various genes. Porcine satellite cells (PSC) were isolated from semimembranosus (SM) muscles of 90∼100 days old pigs according to standard conditions. The cell proliferation increased in multi-potent cell by Masson’s, oil red O, and Alizarin red staining respectively. We per-formed the expression levels of differentiation related genes using real-time PCR. We found that the differentiation into adipocyte increased expression levels of both fatty acid binding protein 4 (FABP4) and peroxisome proliferator- acti-vated receptor gamma (PPARγ) genes (p<0.01). Myocyte increased the expression levels of the myosin heavy chain (MHC), myogenic factor 5 (Myf5), myogenic regulatory factor (MyoD), and Myogenic factor 4 (myogenin) (p<0.01). Osteo-blast increased the expression levels of alkaline phosphatase (ALP) (p<0.01). Finally, porcine satellite cells were indu-ced to differentiate towards adipogenic, myogenic, and osteoblastogenic lineages. Our results suggest that muscle satellite cell in porcine may influence cell fate. Understanding the progression of PSC may lead to improved strat-egies for augmenting meat quality.
        4,000원
        35.
        2012.10 구독 인증기관·개인회원 무료
        Lepidopteran pests monitoring in adult stage was generally performed using delta or corn typed trap including rubber septa impregnated sex pheromone (lure). Sometimes, unfortunately trapped samples were severly damaged because of biotic and/or abiotic environments such as micro-organism, predator and rain, sticky material, respectively. In our case, we monitored potato tuber moth, PTM, Phthorimaea operculella distribution during 2009~2012 in Korea. However, we encountered unexpected problem, another species can be trapped in species specific sex pheromone trap. Therefore, species confirmation was needed in trapped samples. Here we developed confirmation method by direct PCR (without DNA extraction) or sequencing methods which trapped samples that cannot identified by morphologically. We designed multi-plex PCR universal primers and species specific primers in rRNA region because to check the success of PCR and species identification. This direct PCR method can be applied in other species confirmation which monitored using pheromone trap.
        36.
        2012.10 구독 인증기관·개인회원 무료
        The green peach aphid, Myzus persicae (Sulzer), is one of the most serious pests in cabbage cultivation. Field survey was carried out to know the insecticide resistance levels and to develop the applicable insecticide resistant markers in five main cabbage cultivation regions (Pyeong-chang, Hong-cheon, Bong-wha, Mu-ju and Je-ju) during 2009 to 2011. M. persicae can resist a wide range of insecticides in five surveyed local populations. Therefore multi resistant (MR) strain was selected from these five local populations and esterase over-expression, modified AChE (MACE) and mutation(s) in para-type sodium channel were analyzed using native IEF and quantitative sequencing with five local populations. Esterase over-expression and MACE (StoF mutation) were observed in all populations including MR strain. LtoF mutation is well known as a kdr mutation in para-type sodium channel. However, even though LC50 values of MR strain noted over 2,000 times higher than that of susceptible strain against bifenthrin, LtoF mutation was not detected in para type sodium channel and also local populations. We found another mutation (MtoL) in para and that mutation highly correlated between mutation ratio and bioassay data. For preliminary resistance monitoring, we developed quantitative sequencing (QS) to detect the frequencies of point mutation as a population genotyping. These methods can apply to manage M. persicae resistant populations in field.
        37.
        2010.05 구독 인증기관·개인회원 무료
        The effects of the genetically modified virus-resistant pepper (line: H15) and the Non-GM pepper (line: P2377) on the insect community in the pepper cultivation area were evaluated. Sampling was conducted using yellow sticky traps and pheromone funnel traps in Anseong and Deokso fields. Total number of insects caught on sticky trap were 3924 individuals at GM pepper and 3670 individuals at Non-GM pepper in Anseong and 2362 individuals at GM and 2528 individuals at Non-GM in Deokso, respectively. The total number of the insect individuals caught by sticky trap was not shown significant differences between GM and Non-GM pepper at Anseong and Deokso fields, respectively. The number of aphids per sticky trap ranged from 11.60±2.02 to 1.92±0.96 at Non-GM and from 11.56±2.15 to 0.33±0.23 at GM in Anseong, and from 2.78±1.22 to 0.11±0.08 and from 2.73±0.84 to 0.11±0.08 at Non-GM and GM pepper in Deokso, respectively. There were no significant differences in seasonal occurrences of aphids caught on sticky traps in GM and Non-GM pepper at both fields, and significant differences in aphids population density between Non-GM and GM were not observed.
        38.
        2010.05 구독 인증기관·개인회원 무료
        A MnSOD gene was cloned from the fall webworm, H. cunea. The MnSOD cDNAs encode precursor proteins of 215 amino acid residues. The deduced amino acid sequences of the H. cunea MnSOD cDNA showed 76% identity to B. mori MnSOD and 62-56% to MnSOD sequences from other organisms. MnSOD and Cu/ZnSOD in H. cunea is expressed from all tissues. MnSOD expression is changed at a trace level in infected larvae, while Cu/ZnSOD expression is strongly changed against bacteria, and fungi. The expression level of Cu/ZnSOD increased by different artificial photoperiod (24L:0D), UV irradiation (312nm), and starvation condition, while the expression level of MnSOD only increased by starvation condition. Also, expression of MnSOD and Cu/ZnSOD showed no significant change in 0L:24D condition. In addition to expression levels of Cu/ZnSOD in H. cunea significantly increased by temperature stress and injection with paraquat, but reduced by injection with 10% H2O2. The expression level of MnSOD significantly increased by temperature stress and reduced by injection with 10% H2O2 and paraquat.
        39.
        2010.05 구독 인증기관·개인회원 무료
        Apolipophorin-III (apoLp-III) is a hemolymph protein whose function is to facilitate lipid transport in an aqueous medium in insects. Recently, apolipophorin-III in Galleria mellonella and Hyphantria cunea was shown to play an unexpected role in insect immune activation. We show here a novel possible function/role of the apoLp-III in insects. To investigate the genes which have a relationship with apoLp-III in fall webworm larvae, we reduced endogenous Hc apoLp-III mRNA levels in larvae via RNA interference (RNAi). The RNAi-mediated Hc apoLp-III reduction resulted in the reduction of antioxidants, like MnSOD, catalase, and glutathione S transferase as well as immune proteins. In particular, expression of MnSOD commonly decreased in fat body, midgut, and hemocytes following the knockdown of Hc apoLp-III, which induced an elevated level of superoxide anion in Hyphantria cunea larvae. The observed effect of Hc apoLp-III RNAi suggests that Hc apoLp-III is related to the action/expression of antioxidants, especially MnSOD.
        40.
        2010.05 구독 인증기관·개인회원 무료
        A new insect member of the STAT family of transcription factors (HcSTAT) has been cloned from the lepidopteran, Hyphantria cunea. The domain involved in DNA interaction and the SH2 domain are well conserved. The gene is transcribed at a low level during all stages of development, and transcribed in hemocyte, fat body, midgut, epidermis, and Malpighian tubule. Especially, hemocyte and Malpighian tubule showed transcriptional activation of HcSTAT upon Gram-negative and -positive bacteria challenge. Gram-negative and -positive bacteria challenge specifically results in nuclear translocation of HcSTAT protein and induction of DNA-binding activity that recognizes a STAT target site in H. cunea hemocyte. In vivo treatment with sodium orthovanadatetranslocates HcSTAT to the nucleus in hemocyte cells.
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