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        검색결과 40

        6.
        2023.10 구독 인증기관·개인회원 무료
        The soluble epoxide hydrolase (sEH) plays a crucial role in insect immunity and development by metabolizing oxylipins such as EpOMEs and EETs. This study investigates sEH's involvement in insect antiviral response against Autographacalifornicanuclear polyhedrosis virus (AcNPV) infection. Viral infection assays were performed on Plutellaxylostellaand Marucavitrata, utilizing occlusion bodies (OB, via feeding) and budded virus (BV, through injection). Insect mortality was monitored every 12 h for up to 7 days. Our findings demonstrated a dose-dependent impact of both virus forms (OB and BV) on insects. Additionally, the sEH inhibitor, AUDA (12-(3-adamantan-1-yl-ureido) dodecanoic acid), was employed alongside the virus. The results indicated that combining AUDA with the virus increased insect mortality. Furthermore, fluorescence assays revealed the gradual movement of the virus from the gut to hemolymph and fat body. AUDA was observed to expedite virus infection. Moreover, sEH expression rapidly increased along with the viral infection in Spodoptera exigua. RNA interference of sEH expression enhanced the viral virulence against S.exigua. These suggest that EpOMEs play crucial roles in immune resolution against viral infection in insects.
        7.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This prospective, observational study of acute stroke survivors was completed to report our clinical application of the Penetration-Aspiration Scale (PAS), an 8-point multidimensional assessment, used in conjunction with the Video Fluoroscopic Swallow Study (VFSS). In addition, we were interested in determining the association of PAS scores at admission, demographics and clinical characteristics with functional recovery (measured by the Functional Independence Measure [FIM]) at discharge from an inpatient rehabilitation hospital. There were thirty-five patients that met inclusion and consented. Out of the 35, 34 (97%) were successfully assessed with the PAS with VFSS. Multivariate regression model revealed that the PAS scores, sex, length of stay, and admission FIM scores were significantly associated with functional recovery at hospital discharge (all p values < .05). We conclude that the PAS was feasible to administer with VFSS and implement in our inpatient setting. The PAS provided information about the depth of the airway invasion, material remaining after the swallow, and the response to aspiration, which were not reported in a standardized way prior to this study. The association between the PAS and functional recovery at discharge suggests that stroke survivors with swallowing impairment have less functional improvement noted at discharge than those with better swallowing scores. Therefore, people with dysphagia may need additional services and care. Future research should determine if using the PAS can improve clinical practice and ensure consistency across care transitions (expansion), as those with dysphagia may need additional services and care.
        4,000원
        12.
        2018.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Two dimensional(2D) crystals, composed of a single layer or a few atomic layers extracted from layered materials are attracting researchers’ interest due to promising applications in the nanoelectromechanical systems. Worldwide researchers are preparing devices with suspended 2D materials to study their physical and electrical properties. However, during the fabrication process of 2D flakes on a target substrate, contamination occurs, which makes the measurement data less reliable. We propose a dry transfer method using poly-methyl methacrylate(PMMA) for the 2D flakes to transfer onto the targeted substrate. The PMMA is then removed from the device by an N-Methyl-2-pyrrolidone solution and a critical point dryer, which makes the suspended 2D flakes residue free. Our method provides a clean, reliable and controllable way of fabricating micrometer-sized suspended 2D nanosheets.
        4,000원
        13.
        2018.05 구독 인증기관·개인회원 무료
        The Semi-Rigid Pavement (SRP) mixture is composed of Gap Graded Asphalt (GGA) mixture (air void = 20~28%) and cement paste. By inserting cement paste into voids in GGA mixture, SRP can provide not only flexibility but also rigidity characteristics on pavement performance. SRP can mitigate pavement surface temperature increase during summer session, provide better smoothness and mitigate rutting distress due to heavy weight vehicles, successfully. In Japan, SRP is widely applied in cross section area, heavy vehicle parking lot and highway ticketing booth in highway network system. In South Korea, SRP was introduced and applied since 2005. However, still more researches and studies are needed to understand material characteristics and improve performance of SRP. Moreover, the current SRP system in South Korea merely follows and adapts the aggregate gradation information from Japan which needs to be amended and customized into original material (i.e. aggregate, binder and cement) situation of South Korea. In this paper, SRP system based on Stone Mastic Asphalt (SMA) mixture design originated from Korea Expressway Corporation (KEC) and enhanced cement paste with addition of fly-ash and slags was developed. In addition, an optimized proportion between asphalt mixture air voids and cement paste amount with consideration of economic benefit was introduced. Based on field evaluation process it can be said that the newly developed SRP system can successfully adapted not only in static site on highway: parking lots or ticketing booth, but also in dynamic site on highway: driving and wheel path.
        14.
        2018.05 구독 인증기관·개인회원 무료
        In case of performing asphalt pavement overlay on existing concrete pavement layer, applying asphalt emulsion tack-coating or spreading prime-coating is considered to improve adhesion between asphalt and concrete layer. After coating work is done a curing process is considered not only for promoting evaporation process in coated (and/or spread) asphalt emulsion, but also for generating a membrane which can act as a bonding agent. Finally, asphalt overlay construction is performed when this curing process is completely done. However, during asphalt overlay construction process remarkable amount of spread tack-coating layer is lost due to asphalt material transfer vehicles (e.g. trucks, approximately 40~50% of total spread tack coating material is lost). In this paper, a new pavement equipment contains simultaneous asphalt emulsion spreading ability and corresponding construction techniques are introduced. Through applying this equipment, non-stop two step sequent working process: spreading asphalt emulsion on to existing concrete pavement layer then paving asphalt material for overlay construction, is available. During pavement working process temperature of asphalt material was kept with ranged between 130ºC and 170ºC. After performing field performance evaluation, it was found that crucial improvement in pavement layer adhesion, crack and rutting resistant ability were observed compared to the conventional paving method.
        15.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The electronic and optical characteristics of molybdenum disulphide (MoS2) film significantly vary with its thickness, and thus a rapid and accurate estimation of the number of MoS2 layers is critical in practical applications as well as in basic researches. Various existing methods are currently available for the thickness measurement, but each has drawbacks. Transmission electron microscopy allows actual counting of the MoS2 layers, but is very complicated and requires destructive processing of the sample to the point where it will no longer be useable after characterization. Atomic force microscopy, particularly when operated in the tapping mode, is likewise time-consuming and suffers from certain anomalies caused by an improperly chosen set point, that is, free amplitude in air for the cantilever. Raman spectroscopy is a quick characterization method for identifying one to a few layers, but the laser irradiation causes structural degradation of the MoS2. Optical microscopy works only when MoS2 is on a silicon substrate covered with SiO2 of 100~300 nm thickness. The last two optical methods are commonly limited in resolution to the micrometer range due to the diffraction limits of light. We report here a method of measuring the distribution of the number of MoS2 layers using a low voltage field emission electron microscope with acceleration voltages no greater than 1 kV. We found a linear relationship between the FESEM contrast and the number of MoS2 layers. This method can be used to characterize MoS2 samples at nanometer-level spatial resolution, which is below the limits of other methods.
        4,000원
        16.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The unique characteristics of graphene make it an optimal material for crucial studies; likewise, its potential applications are numerous. Graphene’s characteristics change with the number of total layers, and thus the rapid and accurate estimation of the number of graphene layers is essential. In this work, we review the methods till date used to identify the number of layers but they incorporate certain drawbacks and limitations. To overcome the limitations, a combination of these methods will provide a direct approach to identify the number of layers. Here we correlate the data obtained from Raman spectroscopy, optical microscopy images, and atomic force microscopy to identify the number of graphene layers. Among these methods, correlation of optical microscopy images with Raman spectroscopy data is proposed as a more direct approach to reliably determine the number of graphene layers.
        4,000원
        17.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Well-dispersed Ag3VO4 nanoparticles @polyacrylonitrile (PAN) nanofibers were synthesized by an easily controlled, template-free method as a photo-catalyst for the degradation of methylene blue. Their structural, optical, and photocatalytic properties have been studied by X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy equipped with rapid energy dispersive analysis of X-ray, photoluminescence, and ultraviolet–visible spectroscopy. The characterization procedures revealed that the obtained material is PAN nanofibers decorated by Ag3VO4 nanoparticles. Photocatalytic degradation of methylene blue investigated in an aqueous solution under irradiation showed 99% degradation of the dye within 75 min. Finally, the antibacterial performance of Ag3VO4 nanoparticles @PAN composite nanofibers was experimentally verified by the destruction of Escherichia coli. These results suggest that the developed inexpensive and functional nanomaterials can serve as a non-precious catalyst for environmental applications.
        4,000원
        18.
        2016.04 구독 인증기관·개인회원 무료
        Alfalfa weevil is an invasive pest of several leguminous plants. In the world preservative, there is a lack of information about the level of differentiation among separate populations. We ran a comparative molecular and ecological analysis to assess diversity, phylogenetic relationship and also simplify the taxonomic decisions. By analyzing a total of 147 specimens from Middle East, Europe and America plus a few sequences in GenBank we improved our current knowledge of world phylogeography of Hypera postica. The result of mitochondrial genes (Summation of COI and CytB) revealed a deep divergence between two previously defined clades (5.6 – 6.7% nucleotide divergence) within sympatric distribution. The Eastern lineage comprised 60 haplotypes in Iran and 3 haplotypes in Italy with respectively 0.07 – 2.2% and 0.2 – 3.4% sequence divergence range. On the other hand, the Western lineage which was detected in Poland, Czech and Western America had relatively lower haplotype diversity presenting a total of 11 haplotypes and 0.1%-1.1% sequence divergence. The coexistence of two lineages in some regions led to the huge overlap in their fundamental nich, but also a certain level of divergence can be detected via ecological nich modeling analysis.
        19.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 1982년과 2002년 사이 동북아시아 일부 대도시 지역을 대상으로 시계열 위성영상자료를 활용하여 도시팽창양상을 식별하는 것을 목표로 한다. 도시팽창은 시·공간적 역동성을 띄는 지표현상이나, 기존 연구에 주로 사용되었던 원격탐사 방법론들은 이의 시간적 측면보다는 공간적 측면에 비중을 두어 분석을 수행해왔다. 본 연구에서는 시계열 푸리에분석과 시계열회귀분석을 조합한 계량적 방법론을 이용하여 도시팽창의 시간적 측면에 보다 비중을 두고 분석을 하였으며, 동북아시아 대도시 지역에서 도시팽창이 어떻게 진행되는지를 지리정보체계/원격탐사 컴퓨터 프로그램인 이디리시를 사용하여 분석한다. 그 결과, 본 논문에서 시도한 방법론은 대도시 지역의 시·공간적 피복변화를 감지하는데는 효과적이었으나, 도시팽창 자체를 탐지하는데 있어서는 제약이 있는 것으로 나타났으며, 제약의 주된 이유는 도시지역의 피복과 토지이용의 대응이 항상 일치하지 않기 때문인것으로 파악되었다. 본 논문에서 제시한 시계열 원격탐사 방법론은 각 지역에서 관찰되는 각기 다른 도시화 양상을 픽셀단위로 구분하는데, 다양한 조합의 분석결과를 활용하면 도시팽창 연구에 유용할 것으로 예상된다.
        4,000원
        20.
        2014.03 구독 인증기관 무료, 개인회원 유료
        Streptococcus mutans (S. mutans) is a facultative anaerobic bacterium mainly found in the oral cavity and is known to contribute to tooth decay and gingivitis. Recent studies on intestinal microbiota have revealed that microorganisms forming a biofilm play important roles in maintaining tissue homeostasis through their own metabolism. However, the physiological roles of oral microorganisms such as S. mutans are still unclear. In our current study, we identified that constituents released from S. mutans (CR) reduce arecoline- mediated cytotoxicity without producing toxic effects themselves. Arecoline, as a major alkaloid of areca nut, is known to mediate cytotoxicity on oral epithelial cells and induces a sustained intracellular Ca2+ ([Ca2+]i) increase that is cytotoxic. The exposure of human gingival fibroblast (HGF) cells to CR not only inhibited the sustained [Ca2+]i increase but also the initial [Ca2+]i elevation. In contrast, CR had no effects on the gene regulation mediated by arecoline. These results demonstrate that S. mutans has physiological role in reducing cytotoxicity in HGF cells and may be considered a novel pharmaceutical candidate.
        4,000원
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