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        검색결과 94

        2.
        2022.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Polarimetric measurements of the lunar surface from lunar orbit soon will be available via Wide-Field Polarimetric Camera (PolCam) onboard the Korea Pathfinder Lunar Orbiter (KPLO), which is planned to be launched in mid 2022. To provide calibration data for the PolCam, we are conducting speckle polarimetric measurements of the nearside of the Moon from the Earth’s ground. It appears that speckle imaging of the Moon for scientific purposes has not been attempted before, and there is need for a procedure to create a “lucky image” from a number of observed speckle images. As a first step of obtaining calibration data for the PolCam from the ground, we search for the best sharpness measure for lunar surfaces. We then calculate the minimum number of speckle images and the number of images to be shift-and-added for higher resolution (sharpness) and signal-to-noise ratio.
        4,200원
        7.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Resistance to extended-spectrum cephalosporin in Enterobacteriaceae is increasingly prevalent in South Korea. This study aims to explore the distribution of AmpC genes in Proteus mirabilis isolated from stray and hospital-admitted companion animals in South Korea. AmpC β-lactamases hold clinical significance due to its potential to facilitate antimicrobial resistance to cefoxitin, cefazolin, and most penicillins. A total of 163 bacterial isolates belonging to the Enterobacteriaceae family were collected from dogs (n = 158) and cats (n=5). Of them, 134 isolates were from hospital-admitted animals, while 29 isolates from stray animals. Boronic acid tests and antimicrobial susceptibility tests were conducted for an initial screening to detect AmpC β-lactamase resistant P. mirabilis. Gene-specific PCRs were conducted to identify the type of AmpC genes, which include six groups (MOXM, CITM, DHAM, ACCM, EBCM, and FOXM), in the resistant isolates. The boronic acid disk tests revealed 45 (27.6%) positive isolates out of 163 isolates tested. Of these 45 isolates, six were determined to harbor the EBCM gene, 13 for CITM, one for FOXM, and one for DHAM by single detection PCR. No isolates carried for ACCM or MOXM. Thus, a total of 21 out of 163 isolates (12.9%) were demonstrated to possess AmpC genes. No isolates contain more than one group of AmpC gene family. A significantly higher percentage of P. mirabilis was found to possess AmpC genes compared to past studies. Therefore, the increasing trend in antimicrobial resistance in P. mirabilis indicates a dire need to monitor antimicrobial prescription in the veterinary field.
        4,000원
        10.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한국근로자를 대상으로 하여 성장욕구가 직무열의와 직무탈진에 영향을 미치는지 조사하였 다. 이와 더불어 부정적 정서조절과 내적 동기가 이들 변수 간의 관계에 영향을 미치는지에 대해서도 검증하였다. 본 연구를 위해 한국의 제조기업에 근무하는 244명의 근로자에게 자기보고식 설문조사를 실시 하였다. 연구결과, 직무열의와 직무탈진에 대한 성장욕구의 직접 효과는 없는 것으로 나타났다. 그러나 이들 변수들 간의 관계는 부정적 정서조절과 내적 동기의 매개역할에 의해 강화되는 것으로 나타났다. 즉 성장욕구와 직무열의의 관계에 대해 부정적 정서조절과 내적 동기는 매개효과를 가졌으며, 성장욕구와 직무탈진의 관계에 부정적 정서조절이 매개효과를 가졌다. 이 결과를 통해 본 연구는 성장욕구와 직무 열의, 직무탈진의 관계에 대한 부정적 정서조절 및 내적 동기와 같은 심리적 특성의 중요성을 확인하였다.
        5,500원
        11.
        2019.09 구독 인증기관 무료, 개인회원 유료
        Clear cell odontogenic carcinoma (CCOC), a very rare neoplasm located mostly in the mandible, has been regarded as a benign tumor. However, due to the accumulation of case reports, CCOC has been reclassified as a malignant entity by the World Health Organization. Patients with CCOC present with regional swelling and periodontal indications with variable pain, often remaining misdiagnosed for a long period. CCOC has slow growth but aggressive behavior, requiring radical resection. Histologic analysis revealed the monophasic, biphasic, and ameloblastic types of CCOC with clear cells and a mixed combination of polygonal and palisading cells. At the molecular level, CCOC shows the expression of cytokeratin and epithelial membrane antigen, along with markers that assign CCOC to the sarcoma family. At the genetic level, Ewing sarcoma breakpoint region 1-activating transcription factor 1 fusion is regarded as the key feature for identification. Nevertheless, the scarcity of cases and dependence on histological data delay the development of an efficient therapy. Regarding the high recurrence rate and the potential of distant metastasis, further characterization of CCOC is necessary for an early and accurate diagnosis.
        3,000원
        12.
        2018.06 구독 인증기관 무료, 개인회원 유료
        The mesenchymal stem cells (MSCs) that reside in dental tissues hold a great potential for future applications in regenerative dentistry. In this study, we used human dental pulp cells, isolated from the molars (DPCs), in order to establish the organoid culture. DPCs were established after growing pulp cells in an MSC expansion media (MSC-EM). DPCs were subjected to organoid growth media (OGM) in comparison with human dental pulp stem cells (DPSCs). Inside the extracellular matrix in the OGM, the DPCs and DPSCs readily formed vessel-like structures, which were not observed in the MSC-EM. Immunocytochemistry analysis and flow cytometry analysis showed the elevated expression of CD31 in the DPCs and DPSCs cultured in the OGM. These results suggest endothelial cell-prone differentiation of the DPCs and DPSCs in organoid culture condition.
        4,000원
        13.
        2018.04 구독 인증기관·개인회원 무료
        Feeding effects of the honeybee pollen products from both domestic, China, Spain and mixture of different origin on the colony development of earth bumblebee, Bombus terrestris L., were surveyed to evaluate efficient nutritional resources for commercial bombiculture in Korea. As the results, the domestic pollen was most effective to achieve high rates of oviposition (88%), colony foundation (70%), and queen production. While feeding with domestic pollens during the egg-laying period, and domestic+Chinese mixture (5:2) during the breeding period (Plot-2), it revealed high oviposition rate of 75%, colony foundation of 65%, and large numbers of adult queen production, indicating its suitability for generation subculturing. In the Plot-3, the same high oviposition rate (75%) was obtained except for feeding with the domestic+Chinese mixture (2:5) during the breeding period, which produced large number of workers.
        14.
        2017.10 구독 인증기관·개인회원 무료
        Major royal jelly proteins (MRJPs) are important protein components of bee royal jelly (RJ) and exhibit various biologicaland pharmacological activities. The antimicrobial activities of royalisins and the jelleines contained within MRJP 1 andMRJP 2 in RJ have been elucidated. However, the antimicrobial effects of other bee RJ MRJPs remain largely unknown.In this study, we demonstrated that the Asiatic honeybee (Apis cerana) MRJP 4 (AcMRJP4) exhibits antimicrobial activitiesagainst bacteria, fungi, and yeast. Recombinant AcMRJP4 was expressed as a 63-kDa protein in baculovirus-infected insectcells. However, some of the recombinant AcMRJP4 proteins were cleaved into two fragments (i.e., 48-kDa (AcMRJP4-48)and 15-kDa (AcMRJP4-15) proteins) by the proteolytic cleavage of the C-terminus of the recombinant AcMRJP4. Interestingly,AcMRJP4, AcMRJP4-48, and AcMRJP4-15 exhibited antimicrobial activities, with AcMRJP4-15 exhibiting the highestantimicrobial activity, followed by AcMRJP4. AcMRJP4-15, which is a hydrophilic peptide with 88 amino acid residuesthat contains a high content of Asn and positively charged amino acids, induced structural damage in the cell walls ofthe assayed bacteria, fungi, and yeast. Altogether, our data demonstrated that AcMRJP4 functions as an antimicrobial agent.
        15.
        2017.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Despite extensive research attention that has been paid to second language (SL) or foreign language (FL) learners’ argumentative writing, most research has focused on the structural features characteristic of such writers. There have not been many systematic attempts to identify the quality of argument features SL or FL writers rely on, and how they contribute to the overall writing qualities. This study was designed to examine the relationship between the Toulmin elements, widely used measures of content qualities in arguments which include claims, data, warrants, rebuttals, qualifiers, and backings, and the overall qualities of advanced Korean high school EFL learners’ argumentative writing. Each of the thirty three participants’ argumentative writing was analyzed, applying the Toulmin model, and the results demonstrate that their overall argument qualities were closely related to the uses of the fundamental Toulmin elements, especially data and predicted best by the degree to which each claim was supported with relevant and sufficient data. These findings shed light on the need for instruction on the use of Toulmin elements in enhancing the overall quality of Korean EFL learners’ argumentative writing.
        5,800원
        16.
        2017.04 구독 인증기관·개인회원 무료
        The diamondback moth (DBM), Plutella xylostella, is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. Chlorantraniliprole is the first commercial insecticide that belongs to the new chemical class of diamide insecticides. In this study, the resistant strain was observed 1578-fold resistance to chlorantraniliprole. Point mutation (G4946E) in ryanodine receptor (RyR) showed a high frequency. Enzyme assays indicated that glutathione S-transferase (GST) activity in the resistant strain was 2.4 times higher compared with the susceptible strain, whereas no difference was seen for P450 and esterase. In addition, the expression of two GSTs genes was up-regulated. These findings pave the way for the complete understanding of the mechanisms of diamide insecticides resistance in insects.
        17.
        2016.10 구독 인증기관·개인회원 무료
        Zika virus, mosquito-borne disease, caused by mosquitoes has been increased the importance. From March to September, twice a month from 7 different points (3 residential areas, 3 migratory bird sanctuary and 1 cattle shed) were collected using BG trap and BL trap. After identifying the mosquitoes collected, we confirmed the virus infection. Total 26,531 mosquitoes (6 genus 9 species) were collected, virus has been detected from the 3 species (Aedes vexans, Cuilex tritaeniorhynchus, and Amigeres subalbatus) of mosquitoes of them. It showed the highest peak in August, and then gradually decreased. The most common mosquito species was collected Aedes vexan (16,637) in the cattle shed.
        18.
        2016.04 구독 인증기관·개인회원 무료
        Mealybugs (Hemiptera: Pseudococcidae) are major pests of a wide range of crops and ornamental plants worldwide, and represented by 56 species in Korea. Occurrence of, or damage by, the longtailed mealybug, Pseudococcus longispinus Targioni-Tozzetti has not been reported since 2002. However, for the first time in many years, P. longispinus was reported at Phalaenopsis orchids by Kim et al in 2015. Therefore, the present study aimed to investigate the distribution of P. longispinus which is usually found inside a greenhouse or a building where the host plants are. We have collected 129 mealybug samples at 254 sites from Korea. Among these, 27 of P. longispinus and 62 of an unidentified Pseudococcus species were found mainly in ornamental plants such as Heteropanax fragrans, commonly known as happy trees in Korea. Morphological characteristics of the unidentified mealybug were very similar to those of P. longispinus. However, the genetic variability in COI sequence comparison was significantly different between the two species. Further studies are needed to clarify the valid name for this unidentified species, and we are currently working on it.
        19.
        2016.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nanosized zeolites were prepared in an autoclave using tetraethoxysilane (TEOS), tetrapropylammonium hydroxide (TPAOH), and H2O, at various hydrothermal synthesis temperatures. Using transmission electron microscopy and particle size analysis, the nanopowder particulate sizes were revealed to be 10-300 nm. X-ray diffraction analysis confirmed that the synthesized nanopowder was silicalite-1 zeolite. Using atomic layer deposition, the fabricated zeolite nanopowder particles were coated with nanoscale TiO2 films. The TiO2 films were prepared at 300 oC by using Ti[N(CH3)2]4 and H2O as precursor and reactant gas, respectively. In the TEM analysis, the growth rate was ~0.7 Å/cycle. Zeta potential and sedimentation test results indicated that, owing to the electrostatic repulsion between TiO2-coated layers on the surface of the zeolite nanoparticles, the dispersibility of the coated nanoparticles was higher than that of the uncoated nanoparticles. In addition, the effect of the coated nanoparticles on the photodecomposition was studied for the irradiation time of 240 min; the concentration of methylene blue was found to decrease to 48%.
        4,000원
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