검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 385

        182.
        2011.10 구독 인증기관·개인회원 무료
        The polyhedrin is responsible to form polyhedra of nucleopolyhedrovirus(NPV) and highly conserved in most completely sequenced in lepidopteran NPVs. Previously, we have reported that the substitution of polyhedrin of Autographa californica NPV(AcNPV) with that of Spodoptera exigua NPV(SeNPV) or Bombyx mori NPV(BmNPV) result the change of polyhedra morphology. In this study, we investigated the influence of changed polyhedra morphology to the virulence of AcNPV. The recombinant AcNPVs were propagated in Spodoptera frugiperda clone 9, 21 cells and S. exigua larvae. Each collected recombinant polyhedra were used in bioassays using S. exigua larvae. The recombinant AcNPVs show that difference virulence according to the polyhedra morphologies. Internal and external morphological features of each recombinant AcNPV were also compared on the electron microscope. Our results suggest that the morphology of polyhedra influence the virulence of NPV and is well worth considering for the development viral insecticide.
        183.
        2011.10 구독 인증기관·개인회원 무료
        Vollenhovia emeryi chosenica (Wheeler) (Hymenoptera: Myrmicinae) is an ant species frequently found in forests. In nature, two phenotypically distinct forms are found e.g. long winged and short winged. Unlike other hymenopteran insects, the ant is unique in its mode of reproduction. In this species, queens are clonally reproduced from unfertilized eggs. On the other hand, workers develop from fertilized eggs. Strikingly, haploid males are reproduced from fertilized eggs after destroying the maternal half of the genome e.g. maternal genome loss (MGL) consequently only with the paternal half of the genome. We collected the ant colonies nationwide in 2011. In this study, we demonstrate that the ant is infected with Wolbachia, the bacterial reproductive manipulator in various insects. Interestingly, only the long winged morphs seem to be infected. Furthermore, most colonies are mulitple-infected except two colonies collected from Chuncheon and Mt. Deogyu. We will discuss potential interactions among the Wolbachia infection polymorphism and wing morphology, and evolution of clonal reproduction and MGL.
        184.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kenaf fibers, cellulose-based natural fibers, were used as precursor for preparing kenafbased carbon fibers. The effects of carbonization temperature (700℃ to 1100℃) and chemical pre-treatment (NaOH and NH4Cl) at various concentrations on the thermal change, chemical composition and fiber morphology of kenaf-based carbon fibers were investigated. Remarkable weight loss and longitudinal shrinkage were found to occur during the thermal conversion from kenaf precursor to kenaf-based carbon fiber, depending on the carbonization temperature. It was noted that the alkali pre-treatment of kenaf with NaOH played a role in reducing the weight loss and the longitudinal shrinkage and also in increasing the carbon content of kenaf-based carbon fibers. The number and size of the cells and the fiber diameter were reduced with increasing carbonization temperature. Morphological observations implied that the micrometer-sized cells were combined or fused and then re-organized with the neighboring cells during the carbonization process. By the pre-treatment of kenaf with 10 and 15 wt% NaOH solutions and the subsequent carbonization process, the inner cells completely disappeared through the transverse direction of the kenaf fiber, resulting in the fiber densification. It was noticeable that the alkali pre-treatment of the kenaf fibers prior to carbonization contributed to the forming of kenaf-based carbon fibers.
        4,000원
        185.
        2011.06 구독 인증기관 무료, 개인회원 유료
        Clinical arthritis is typically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Arthritis-induced muscle weakness is a major problem in aged people, leading to a disturbance of balance during the gait cycle and frequent falls. The purposes of the present study were to confirm fiber type-dependent expression of muscle atrophy markers induced by arthritis and to identify the relationship between clinical signs and expression of muscle atrophy markers. Mice were divided into four experimental groups as follows: (1) negative control (normal), (2) positive control (CFA+acetic acid), (3) RA group (CFA+acetic acid+type Ⅱ collagen), and (4) aging-induced OA group. DBA/1J mice (8 weeks of age) were injected with collagen (50 μg/kg), and physiological (body weight) and pathological (arthritis score and paw thickness) parameters were measured once per week. The gastrocnemius muscle from animals in each group was removed, and the expression of muscle atrophy markers (MAFbx and MuRF1) and myosin heavy chain isoforms were analyzed by reverse transcription-polymerase chain reaction. No significant change in body weight occurred between control groups and collagen-induced RA mice at week 10. However, bovine type Ⅱ collagen induced a dramatic increase in clinical score or paw thickness at week 10 (p<0.01). Concomitantly, the expression of the muscle atrophy marker MAFbx was upregulated in the RA and OA groups (p<0.01). A dramatic reduction in myosin heavy chain (MHC)-Iβ was seen in the gastrocnemius muscles from RA and OA mice, while only a slight decrease in MHC-Ⅱb was seen. These results suggest that muscle atrophy gene expression occurred in a fiber type-specific manner in both RA- and OA-induced mice. The present study suggests evidence regarding why different therapeutic interventions are required between RA and OA.
        4,000원
        186.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        5,200원
        187.
        2011.05 구독 인증기관·개인회원 무료
        Among the Coleoptera, case bearing is found in four related subfamilies of the Chrysomelidae, the so-called Camptosomates: Clytrinae, Cryptocephalinae, Chlamisinae, and Lamprosomatinae (Böving and Craighead, 1931). Adults of casebearing chrysomelids feed on foliage of a variety of eudicots (Erber, 1988), but their larvae often show departures from strict phytophagy. Besides those with true herbivore larvae, that feed on green plant parts and complete development on the host plant, the larvae of most species live on the ground, in leaf litter, and feed on dry vegetable material and detritus (Erber, 1988; Brown and Funk, 2005). The larvae of some clytrine species live in ant nests (Erber, 1988; Brothers et al., 2000), but besides these mirmecophiles, many other clytrine larvae live in leaf litter and some few others on plants (Erber, 1988; Jolivet, 1988). The genus Smaragdina Chevrolat is distributed in the Paleoarctic region, and in the Oriental region (Chûjô & Kimoto, 1961; Erber & Medvedev, 1999; Gök, 2003; Maican, 2005, 2006). Forth-three Smaragdina species are distributed throughout northeast Asia, from Korea to Japan (Gressitt & Kimoto, 1961; Kimoto & Takizawa, 1994, 1997). In Korea a total of 5 species were known by Lee and An (2001). Recently, Smaragdina nipponensis Chûjô is newly recorded by Park et al. (2011). However, for the clytrine larvae has never been studied from Korea. The present study contains the description of the egg and first instar larva of S. nipponensis with notes on biology of adults and larvae, observes in natural conditions and in laboratory.
        188.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Commercial PAN fibers were thermally stabilized at 220 or 240℃ for 30 min. Those fibers were further stabilized using radio-frequency (RF) capacitive plasma discharge during 5 or 15 min. From Fourier transform infrared spectroscopy results, it was observed that an additional plasma treatment led to further stabilization of PAN fibers. After stabilization, carbonization was performed to investigate the final tensile properties of the fabricated carbon fibers (CFs). The results revealed that a combination of thermal and plasma treatment is a possible stabilization process for manufacturing CFs. Morphology of CFs was investigated using scanning electron microscopy. The morphology shows that the plasma stabilization performed by the RF large gap plasma discharge may damage the surface of the CF, so it is necessary to select a proper process condition to minimize the damage.
        4,000원
        189.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Graphene is one of the most promising materials for many applications. It can be used in a variety of applications not only as a reinforcement material for polymer to obtain a combination of desirable mechanical, electrical, thermal, and barrier properties in the resulting nanocomposite but also as a component in energy storage, fuel cells, solar cells, sensors, and batteries. Recent research at Michigan State University has shown that it is possible to exfoliate natural graphite into graphite nanoplatelets composed entirely of stacks of graphene. The size of the platelets can be controlled from less than 10 nm in thickness and diameters of any size from sub-micron to 15 microns or greater. In this study we have investigated the influence of melt compounding processing on the physical properties of a polyamide 6 (PA6) nanocomposite reinforced with exfoliated graphite nanoplatelets (xGnP). The morphology, electrical conductivity, and mechanical properties of xGnP-PA6 nanocomposite were characterized with electrical microscopy, X-ray diffraction, AC impedance, and mechanical properties. It was found that counter rotation (CNR) twins crew processed xGnP/PA6 nanocomposite had similar mechanical properties with co-rotation (CoR) twin screw processed or with CoR conducted with a screw design modified for nanoparticles (MCoR). Microscopy showed that the CNR processed nanocomposite had better xGnP dispersion than the (CoR) twin screw processed and modified screw (MCoR) processed ones. It was also found that the CNR processed nanocomposite at a given xGnP content showed the lowest graphite X-ray diffraction peak at 26.5˚ indicating better xGnP dispersion in the nanocomposite. In addition, it was also found that the electrical conductivity of the CNR processed 12 wt.% xGnP-PA6 nanocomposite is more than ten times higher than the CoR and MCoR processed ones. These results indicate that better dispersion of an xGnP-PA6 nanocomposite is attainable in CNR twins crew processing than conventional CoR processing.
        4,000원
        190.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        Laccase (Lcc; EC 1.10.3.2) belongs to a group of polyphenol oxidases, which catalyzed the oxidation of single-electron from phenolic substrates or aromatic amines. Many organisms possess several lcc encoding genes, and their biological functions diverge into many branches. There are many studies on biochemical function of Lccs, however, there are few studies about biological functions of one Lcc in detail. We researched on biological function of Lcc1, which is most abundantly secreted enzyme from vegetative mycelia into liquid culture in L. edodes. In our previous study, lcc1 gene was down regulated by RNAi method in L. edodes, and then ivrL1#32 was selected as a completely lcc1 dowaregulated transformant. We revealed that fruiting body development in ivrL1#32 was significantly suppressed compared to wild type strain. In this study, we observed the hyphal morphology of ivrL1#32. IvrL1#32 did not form thick aerial mycelium mat when grown on MYPG agar plate. From the observation using scanning electron microscope (SEM), hyphae of ivrL1#32 had many abnormal short branches and their mycelial density was lower than that of wild type strain. From transmission electron microscope observation (TEM), ivrL1#32 lacked obviously distinguishable outer and inner layer in their cell wall. In addition, the fibrous layer of ivrL1#32, which connected hyphae, obviously decreased. These morphological phenotypes would be caused by the absence of Lcc1 in L. edodes. Our results provide a clue to resolve of the biological function of Lcc1 in L. edodes.
        193.
        2010.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study examined the effect of current density on the surface morphology and physical properties of copper plated on a polyimide (PI) film. The morphology, crystal structure, and electric characteristics of the electrodeposited copper foil were examined by scanning electron microscopy, X-ray diffraction, and a four-point probe, respectively. The surface roughness, crystal growth orientation and resistivity was controlled using current density. Large particles were observed on the surface of the copper layer electroplated onto a current density of 25 mA/cm2. However, a uniform surface and lower resistivity were obtained with a current density of 10 mA/cm2. One of the important properties of FCCL is the flexibility of the copper foil. High flexibility of FCCL was obtained at a low current density rather than a high current density. Moreover, a reasonable current density is 20 mA/cm2 considering the productivity and mechanical properties of copper foil.
        3,000원
        194.
        2010.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from 25˚C to 500˚C, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at 500˚C, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the Jsc values from 9.94 mA/cm2 for the flat Ag back reflector at 25˚C to 13.36 mA/cm2 for the rough one at 500˚C. A conversion efficiency of 7.60% (Voc = 0.93, Jsc = 13.36 mA/cm2, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.
        4,000원
        195.
        2010.10 구독 인증기관·개인회원 무료
        Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. But despite knowing the importance of sensory organs in their behavior, their antennal structure is largely unknown. In this study, the external morphology and distribution of the antennal sensilla on the antennal of both female and male adults of A. colemani were described using scanning electron microscopy (SEM). Generally, the filaform antennae of males (1,515.20±116.48 ㎛) are longer than females (1,275.06±116.42㎛). Antennae of this species is made up of scape, pedicel and flagellomeres. Male and female antennae differed in the total number of flagellomeres as 15 in males and 13 in females. Female and male antennae of A. colemani has samely seven types of sensilla. We classified sensilla placodea, Bohm bristles, 2 types of sensilla coeloconica, , 2 types of sensilla basiconica as with a tip pore and with wall pores, sensilla trichodea. In addition, the possible functions of the above sensilla types are discussed in light of previously published literature; mechanoreception(Bohm bristles, sensilla coeloconicaⅡ and sensilla trichodea) and chemoreception(sensilla coeloconicaⅠ, sensilla basiconicaⅠ,Ⅱ and sensilla placodea). Future studies on the functional morphology of the antennal sensilla of A. colemani using transmission electron microscopy (TEM) coupled with electrophysiological recordings will likely confirm the functions of the different sensilla identified in this study.
        196.
        2010.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Mo thin films were used for the back electrode because of the low resistivity in the Mo/CuInGaSe2 contact inchalcopyrite solar cells. 1µm thick Mo thin films were deposited on soda lime glass by varying the Ar pressure with the dc-magnetron sputtering process. The effects of the Ar pressure on the morphology of the Mo back electrode were studied andthe relationships between the morphology and electro-optical properties, namely, the resistivity as well as the reflectance of theMo thin films, were investigated. The resitivity increased from 24µΩ·cm to 11833µΩ·cm; this was caused by the increasedsurface defect and low crystallinity as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The surface morphologies ofthe Mo thin films changed from somewhat coarse fibrous structures to irregular and fine celled strucutures with increased surfacecracks along the cell boundaries, as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The changes of reflectances in thevisible light range with Ar pressures were mainly attributed to the surface morphological changes of the Mo thin films. Thereflectance in the visible light range showed the highest value of 45% at 3×10−3Torr and decreased to 18.5% at 3×10−2Torr.
        4,000원
        197.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poly(vinyl chloride)-g-poly(styrene sulfonic acid) (PVC-g-PSSA) 가지형 공중합체를 합성한 후, 이를 이용하여 80℃에서 열적으로 환원하여 은 나노입자를 제조하였다. 반응 시간을 바꿈에 따라 다양한 구조의 은 나노입자를 제조하는데 성공하였다. 1시간 정도의 짧은 반응 시간에서는 가지형 공중합체의 미세 상분리 구조를 크게 변화시키지 않고 5 nm 크기의 작은 은 나노입자가 생성되었다. 5시간 정도의 중간 반응 시간에서는 30 내지 50 nm 정도의 크기를 갖는 은 나노입자가 생성되었다. 18시간 정도의 긴 반응 시간에서는, 은입자가 뭉친 허리케인 모양의 은 집합체가 관찰되었다.
        3,000원
        198.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. Ionizing radiation (IR) is an active tool for destruction of cancer ce
        4,000원
        199.
        2010.05 구독 인증기관·개인회원 무료
        Actias artemis and A. gnoma are the two saturniid species of which their gracious morphology often attracts butterfly collectors. The two species, however, have similar wing patterns, even with considerable amount of variations, making difficult to distinguish between the two. We gathered about a hundred specimens of either of the species and tried to distinguish them by their wing morphology as indicated in many books and webpages. This was definitely not easy and we were not even sure if our distinction was right. We changed our plan and we first tried to sequence their COI barcode region and found that the two have more than enough difference and could easily distinguish the two by sequence similarity. Then we compared their outer morphological characters that are often used by people between the two to see if any morphological character can distinguish the two. We concluded that no one characteristic can separate the two although combination of several characteristics may do so. We also made a comparison of their genitalia and they were distinctly different. With the help of genitalic dissection, we found that they can be distinguished without actual dissection by comparing their genital end after just brushing off some scales at the end. For female comparison, a further study with more material is needed as we found the proportion of females among the samples was very low.
        200.
        2010.05 구독 인증기관·개인회원 무료
        Several species of the genus Aphidius are used in biological control programs against aphid pests throughout the world and their behavior and physiology are well studied. But despite knowing the importance of sensory organs in their behavior, their antennal structure is largely unknown. In this study, the external morphology and distribution of the antennal sensilla on the antennal of both female and male adults of A. colemani were described using scanning electron microscopy (SEM). Generally, the filaform antennae of males (1,565.60± 194.64㎛) are longer than females (1,303.83±156.41㎛). Antennae of this species is made up of scape, pedicel and flagellomeres. Male and female antennae differed in the total number of flagellomeres as 15 in males and 13 in females. Female and male antennae of A. colemani has samely ten types of sensilla. We classified 3 types of sensilla trichodea as without pores, with a tip pore and with wall pores, 3 types of sensilla coeloconica, 1 sensilla placodea and 1 Bohm bristles. In addition, the possible functions of the above sensilla types are discussed in light of previously published literature; mechanoreception (Bohm bristles and sensilla coeloconica) and olfaction (sensilla trichodea and sensilla placodea). Future studies on the functional morphology of the antennal sensilla of A. colemani using transmission electron microscopy (TEM) coupled with electrophysiological recordings will likely confirm the functions of the different sensilla identified in this study.