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        검색결과 83

        21.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report on the dispersion state of partially reduced graphene oxide (PRGO) in organic solvents, namely methyl ethyl ketone, ethyl acetate, methylene chloride, toluene, and xylene, by controlling the carbon to oxygen (C/O) atomic ratio of the PRGOs. A two-phase solvent exchange method is also proposed to transfer PRGO from water to an aprotic solvent, such as methyl ethyl ketone. We achieve relatively good dispersion in aprotic and non-polar solvents by controlling the C/O atomic ratio of the PRGOs and applying the two-phase solvent exchange method. There is an increase in the glass transition temperatures with the dispersion of PRGOs into amorphous polymers, in particular a 4.4°C increase for poly(methyl methacrylate) and 3.0°C increase for polycarbonate. Good dispersion of PRGO in a nonpolar polymer, such as linear low density polyethylene, is also obtained.
        4,000원
        24.
        2017.04 구독 인증기관·개인회원 무료
        There are two different types of acetylcholinesterase (AChE1 and AChE2) in the western honeybee as in most of insects. It is suggested that soluble AmAChE1 might be related with a stress response as judged from its elevated expression level in honey bee workers when brood rearing was suppressed. In this study, to ensure the nature of AmAChE1 responding to stress factors, the expression patterns of AmAChE1 following heat shock, brood rearing suppression and chemical treatments (Imidacloprid and fluvalinate) were investigated. Also, several heat shock protein (hsp) genes (hsp10, hsp60, hsp70 and hsp90) known as general stress markers were tested as positive references. Heat shock induced expression of every tested hsp along with AmAChE1. In brood rearing-suppressed worker bees, 7 days old bees showed much higher expression level of AmAChE1 and hsp90 compared to control honey bees. However, treatment of imidacloprid and fluvalinate did not induce any apparent overexpression of these genes. These results confirm that both HSP and AmAChE1 genes generally respond to temperature and brood rearing suppression and further suggest that AmAChE1 can serve as a potential biomarker along with hsps for the detection of stress in honey bee colonies.
        25.
        2016.10 구독 인증기관·개인회원 무료
        Two different types of acetylcholinesterae (AChE1 and AChE2) are present in majority of insects, including the Western honey bee. Out of the two honey bee AChEs (AmAChEs), the soluble AmAChE1 with little catalytic activity is widely distributed in both neuronal and non-neuronal tissues, including fat body. In this study, to identify stresss factors that can induce AmAChE expression, we tested various conditions that honey bees can encounter in natural setting, including heat shock, cold shock, bacterial challenge (Escherichia coli and Staphylococcus aureus) and Varroa mite infestations, and evaluated their effects on AmAChE expression. Among the stress factors tested, only heat shock condition induced AmAChE expression in a dose dependet manner. This finding suggests that one function of AmAChE1 is related with thermoregulations, especially against heat shock stress in honey bees.
        26.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aneurysmal bone cyst (ABC) in maxilla is a rare and benign lesion but shows extensive bony destruction, occasionally accompanied with secondary osseous lesions, i.e., central giant cell granuloma, ossifying fibroma, fibrous dysplasia, etc. As the pathogenesis of ABC has not been clearly defined, ABC is diagnostically challenged due to its variable histological features. A 17-year-old boy showed a huge radiolucent lesion at right anterior maxilla, which was accidentally found in routine dental-radiological examination for orthodontic treatment. He had no medical history of systemic disease, and did not remember any traumatic experience on his right anterior maxilla. The radiolucent lesion involved periapical area from right central incisor to right first premolar, and was clinically diagnosed as odontogenic keratocyst. During surgical operation a cyst-like sac was enucleated with severe hemorrhage. In the histological observation the thick fibrous sac showed no lining epithelium, and its luminal side disclosed multiple aneurysmal spaces which were shrunken and almost obliterated. The fibrous sac itself was hyperplastic with abundant vascular channels, and produced fibromatous thickening associated with ossifying trabecular bones. This fibro-osseous tissue was hamartomatous, which was not directly connected and organized with marrow bone of maxilla. Finally, the present case was diagnosed as secondary type ABC differentially from traumatic bone cyst (TBC), odontogenic cyst, and central reparative granuloma. And it was presumed that the hamartomatous proliferation of fibro-osseous tissue in the cystic sac of ABC could produce the swelling pressure effect in the bone marrow similar to the overgrowth of central giant cell granuloma, ossifying fibroma, fibrous dysplasia, etc., in the secondary type ABC.
        4,000원
        27.
        2016.04 구독 인증기관·개인회원 무료
        Acetylcholinesterase 1 (AmAChE1) has low catalytic activity and is abundantly expressed in both neuronal and non-neuronal tissues. In previous experiments, we observed that AmAChE1 is rarely expressed in summer while highly expressed in winter. Through additional experiments, the expression of AmAChE1 was suggested to be associated with brood rearing status. Under the assumption that abnormal suppression of brood rearing activity may result in stressful condition in honey bee social community, it was further suggested that AmAChE1 is likely involved in stress management particularly during winter. We hypothesized that the increased docility usually observed in overwintering bees is likely an outcome of stress management in colony, which is mediated by AmAChE1 expression. To verify this, worker bees expressing abundant AmAChE1 were collected in early winter and injected with Amace1 dsRNA to knockdown Amace1. Then, the behavioral activity of the bees was investigated using the EthoVison video tracking system. Honey bees injected with Amace1 dsRNA showed significantly increased motility, which was strongly correlated with the suppressed expression level of AmAChE1 in the abdomen. No apparent reduced expression of AmAChE1 in the head was observed perhaps due to the limited efficacy of RNA interference in the blood-brain-barrier. Our finding suggests that behavioral activity can be regulated, at least, by AmAChE1 expression level in non-neuronal tissue (i.e., fatbody) perhaps via metabolic alteration.
        28.
        2015.12 구독 인증기관 무료, 개인회원 유료
        The aim of the present study was to investigate sex- and age-associated clinico-metabolic characteristics of urinary stone patients. A retrospective review was performed on data from 2,009 consecutive patients presenting with their first urinary stone episode between 2005 and 2013. Of the 2,009 patients, 1,426 (71.0%) satisfied the inclusion criteria and were enrolled in the study. Patients were grouped by age (<60, ≥60 years old) and sex. The medical history and 24 hr urinary chemistry results of each patient were obtained. The mean age of the 165 (11.6%) patients aged 60 or over was 65.5 ± 4.2 years. Body mass index was greater in elderly females than in younger females (p=0.031). After stratification by sex and age, lower urinary excretion of calcium and uric acid was a protective factor for both sexes among the elderly (p<0.05, each, respectively). Low urine pH was a common risk factor for both sexes among the elderly (p=0.013 in males, p=0.047 in females, respectively), whereas lower citrate excretion was a risk factor for only the elderly female group (p=0.004). With regard to urinary metabolic abnormalities, elderly females showed higher incidence of hypocitraturia compared to younger females (p=0.049). In conclusion, this study demonstrated the sex- and age-associated clinico-metabolic characteristics of urinary stone patients. Thus, it is important to tailor metabolic evaluation and medical prevention therapies for patient according to sex and gender characteristics.
        4,000원
        33.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Caliber persistent artery (CPA) is a vascular anomaly presenting as a bluish and pulsatile artery in the subepithelial tissue. Although the incidence of CPA was debated, many CPAs occurred in the perioral and facial tissues at which the embryonal strapedial artery networks were distributed. The present study demonstrated a case of CPA occurred in the retromolar buccal mucosa in a 37 years old male. The lesion showed many pinkish granular spots, but was asymptomatic except biting irritation during mastication. It had slowly increased in size up to 20 × 25 mm for 3 years, and recently became hemorrhagic due to the biting injury between left upper and lower second molars. With the fear of oral cancer an incisional biopsy was performed, and followed by histological and immunohistochemical study. Histologically the lesion showed many tortuous artery localized at the submucosa area, and the arterial wall was thick and its lumen was narrowed and shrunken. In the immunochemistry α-SMA was positive for thick smooth muscle layer of artery and arterioles, TGase 2 was weakly positive for the luminal surface of arterial intima, and bFGF was consistently positive for the perivascular fibrous tissue. But PCNA, VEGF, CD31, CMG2, TGF-β1, HSP-70, and 14-3-3 were almost negative for the vascular tissue. Therefore, it was presumed that the lesion was not actively proliferative nor degenerative but still retained its cellular stability and slow growing potential. It was finally diagnosed as CPA differentially from arterio-venous malformation, hemangioma, lymphangioma, and squamous cell carcinoma. The retromolar buccal mucosa CPA is first reported in this study and may present usual clinical findings depending on its size and location. This asymptomatic lesion could be severely hemorrhagic by minor biting injury, therefore, precise differential diagnosis should be made through biopsy, and careful therapy be followed.
        4,000원
        34.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A 57 years old female received xenogenic bone graft for the extraction socket augmentation of right maxillary molars and for the sinus floor elevation six months ago. The bone graft sites were healed uneventfully and showed marked radiopacity in the postoperative X-ray view. Before dental implant insertion the bone biopsy was made using trephine bur and examined pathologically. The graft bones showed minimum new bone deposition with dysplastic epithelium. The epithelium was proliferative on the surface of graft bones forming epithelial strands and nests, similar to the odontogenic epithelium. The immunohistochemical study was performed using different antisera of odontogenic markers, growth factors, oncogenes, etc. The epithelial cells were strongly positive for pan-keratins, EGF, pAKT, and HSP-70, consistently positive for PCNA, p53, EGFR, 14-3-3, and survivin, slightly positive for ameloblastin, but rarely positive for amelogenin. Particularly the matrix of graft bone was slightly positive for EGF. Taken together, it is presumed that the abnormal epithelium on the graft bones was derived from odontogenic epithelial elements, Malassez epithelial rests, distributed at the periodontal tissue of maxillary molars, and that they might undergo dysplastic proliferation affected by the release of growth factors and osteogenic proteins from the graft bones. It is also suggested that the graft bone substitutes inserted for the dental implant possibly have a potential to induce the proliferation of odontogenic epithelial rests leading to the pathogenesis of odontogenic cysts and tumors.
        4,000원
        35.
        2014.07 구독 인증기관·개인회원 무료
        The online game market has rapidly increased worldwide, especially in China. In 2012, the world game market equaled 111.7 billion. Many game companies compete by launching new online games in various genres. In 2010, Activision Blizzard reported that the World of Warcraft (WOW) is the world’s most popular online game. Chinese gamers constitute more than half of WOW’s 10 million users. Korea is the second largest gaming market. Thus many foreign game companies target Korea and China, in competition with domestic game companies. The purposes are 1) to understand the role of country of origin and /or brand image in game consumer behavior, 2) to find out the difference of game evaluation between game users in China and Korea, and 3) to draw strategic implication game marketers. Consumers expect products from advanced countries to provide superior performance, so they often look to country of origin in evaluating products. Recently, consumers have looked to brand image as another key element in product evaluation. In this research, we study whether gamers evaluate games on the basis of country of origin and/or brand image. In this paper, we add to the gaming research and suggest that the online game market has three dimensions. First, online games are products. Second, online games are service. Last, online games are entertainment. Data collection resulted in 355 usable responses from online game (LOL) users in Korea(166) and China(189). We conduct factor analysis and reliability analysis to check reliability and validity. Country of Origin is the key element for product evaluation of utilitarian goods but it doesn’t have significant effect on product evaluation of hedonic products which mainly provide sensual pleasure, fantasy, and fun to customers such as luxury goods or online game (Dhar & Wertenbroch, 2000).
        38.
        2013.04 구독 인증기관·개인회원 무료
        Defended (distasteful or toxic) prey are often characterized by conspicuous coloration and this phenomenon is called "aposematism". The main advantage of aposematism is that it promotes faster learning by predators to avoid the prey. Some defended prey species use a different strategy; they remain cryptic in the normal state, but display conspicuous aposematic signal (which is normally hidden) in response to a predator's approach/attack. This anti-predator strategy of a defended prey has not been well studied yet although it can theoretically give the benefits of both camouflage and aposematism. Here, we investigated the effectiveness of this ‘hidden-aposematic signal’ as a warning signal. Using wild tits (Parus minor) as predator and novel artificial prey models (which mimics wings of insects), we tested whether hidden conspicuous signal of a defended prey enhances the avoidance learning rate of predators and how does it compare with the typical conspicuous/non-conspicuous signal. We found that hidden conspicuous signal indeed enhances the avoidance learning rate of predators in comparison with the non-conspicuous signal. However the overall learning rate by predators to avoid the defended prey was slower than for the normal conspicuous signal. Our results suggest that the prey with hidden-aposematic signals could enjoy both the benefits camouflage and the benefits of aposematism that are however lower than benefits from a typical aposematic signal. We, for the first time, highlight the functional aspect of a unique, but yet largely ignored, defensive coloration of prey.
        39.
        2012.10 구독 인증기관·개인회원 무료
        Cryptic color patterns in prey are classical examples of adaptations to avoid predation, but we still know little about behaviors that reinforce the match between animal body and the background. For example, moths avoid predators by matching their color patterns with the background, but the contribution of their behavior to their crypticity have not been well understood. Here, we report the previously underappreciated ability of moths to find the locally most cryptic spot and body orientation by using two species Hypomecis roboraria and Jankowskia fuscaria. We show that body positioning behavior, performed frequently by moths after landing on bark, results in a significant increase of the camouflage effect provided by their cryptic color pattern alone. We also found that moths recognize multiple background cues, such as furrow structure, visual patterns, and roundness to position and orient themselves. Our study demonstrate morphological adaptations, such as color pattern of moths, cannot be fully understood without taking into account a behavioral phenotype that coevolved with the morphology for increasing the adaptive value of the morphological trait.
        40.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 본 연구는 한국인의 백내장과 녹내장의 유병률에 대해 알아 보고자 하였다. 방 법: 백내장과 녹내장의 유병률은 2007년도 국민건강영양조사 자료에서 30세 이상의 2,643명(남성: 1,101명, 여성: 1,543명)을 대상으로 하였다. 본 연구는 서베이분석법인 PROC SURVEYFREQ를 사용하여 사회경제적 위험요인과의 관계에 따른 유병률의 변화를 보았다. 모든 통계분석은 SAS 9.2 통계패키지를 사용하였으며, 유의성 검정은 0.05 이하로 하였다. 결 과: 2007년도 한국인은 3.0%(남성 9.8%, 여성 4.6%)가 백내장을 가지고 있었고, 7.8%(남성 5.7%, 여성 9.8%)가 백내장을 앓은 경험이 있었다. 녹내장 유병률과 경험률은 각각 0.2% (남성 0.4%, 여성 0.2%)와 0.5% (남성: 0.5%, 여성 0.4%)이었다. 65세 이상 남성 노인에서, 백내장 경험률 및 유병률은 19.9%와 4.1%이었으며, 여성에서는 38.3%와 17.2% 이었다. 그러나 30-64세 사이의 젊은 사람들에게 백내장 경험과 유병률이 남성에서 3.4%와 0.8%이었으며, 여성에서 1.6%와 3.0%이었다. 65세 이상 노인에서, 녹내장 경험률과 유병률은 남성에서 1.6%와 1.1%이었으며, 여성에서는 1.6%와 0.8%이었다. 젊은 사람들에게서 녹내장의 경험률과 유병률은 남성에서 0.3%와 0.1%이었으며, 여성에서는 모두 0.1% 이었다. 또한, 교육수준이나 소득이 낮은 경우, 비경제인구이거나 실업자의 경우 백내장과 녹내장의 유병률과 경험률이 높았다. 결 론: 30세 이상의 한국인에서 백내장의 유병률은 3.0%, 녹내장의 유병률은 0.2%였다. 본 연구결과는 한국인에서 안보건과 안질환의 적절한 건강관리 정책을 만드는데 있어 중요한 결과라고 할 수 있다.
        4,000원
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