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        검색결과 96

        41.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite the various effects on the health of Chamaecyparis obtusa essential oil (COEO), an adverse effect on the skin has recently been reported. Therefore, in this study, the skin sensitization test of COEO was conducted to confirm the skin safety of the essential oil by the guinea pig maximization test. Guinea pigs were sensitized with intradermal injection of 0.1ml COEO for 24 h. After 1 week, 5% of COEO was treated on the site of injection and 2% of the essential oil was challenged 2 weeks later. The average skin reaction evaluated by erythema and edema on the challenge sites and sensitization rate in the COEO-treatment group at 24 h were 0.0 and 0%, respectively, which are substantially low compared with in the 2,4-dinitrochlorobenzene-treatment group (positive control group) (average skin reaction: 3.0, sensitization rate: 100%) and identical with in the olive oil-treatment group (negative control group), representing a weak sensitizing potential. The average skin reaction and sensitization rate observed at 48 h were 0.0 and 0% in the COEO-treatment group, respectively, and 2.0 and 100% in the positive control group, respectively. It was concluded that 5% of COEO classified to Grade I, induced no sensitization when tested in guinea pigs.
        4,000원
        42.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study investigated fashion Instagram marketing, applying the concept of gamification. It set out to examine the following specific issues: 1) perceptions of flow, pleasures, dimensions of game dynamics (challenge, competition, achievement, reward, relationships among participants, and relationships between brands and consumers), and consumer responses based on frequency and involvement in exercise; 2) the effects of game dynamics dimensions on flow and pleasure; and 3) the effects of flow and pleasure on consumer responses. An online survey was used to gather data and the study analyzed a total of 200 responses. The results of the study were as follows. Perception differences were found only in relation to exercise involvement. Competition, relationships among participants, and relationships between brands and customers positively predicted flow. Among the dimensions of game dynamics, challenge, competition, reward, relationships among participants, and relationships between brands and consumers positively influenced pleasure. In addition, the study also found that pleasure and flow had positive effects on intention to participate and brand loyalty. Meanwhile, only pleasure predicted word-of-mouth. These findings suggest that fashion brands implementing Instagram as a marketing channel should seek to stimulate pleasure and fun to provoke positive consumer responses. Furthermore, the findings of the study provide practical and useful insights for fashion brands implementing Instagram marketing.
        4,800원
        43.
        2019.04 구독 인증기관·개인회원 무료
        Frankliniella occidentalis is a major pest in agriculture. Following overuse of insecticides, high resistance has developed due to its high reproduction rate and short generation time. To control the resistant strains of the thrips, the ingestion RNAi- based control was established. A total of 67 genes were selected, and their double-stranded RNAs (dsRNA) were delivered to thrips via the leaf disc-feeding method. Among the genes screened, the dsRNA of Toll-like receptor 6 (TLR6) and coatomer protein subunit epsilon (COPE) resulted in the highest mortality (3.8- and 2.8-fold faster LT50 compared to control, respectively) when ingested by thrips. The dsRNA-fed thrips showed 53% and 83% reduced transcription levels of TLR6 and COPE, respectively. This result demonstrates that the observed mortality of thrips following dsRNA ingestion was due to RNAi, and this lethal genes can be employed as a practical tool to control thrips in the field.
        44.
        2019.04 구독 인증기관·개인회원 무료
        Mosquitoes are primary medical insect pests due to their diseases transmission as vectors. In Korea, the insecticide-resistant populations of disease vector mosquito species, such as Anopheles sinensis, Culex pipiens and Culex tritaeniorhynchus, have constantly increased. Thus, management of insecticide resistance to major insecticides including pyrethroids and organophosphates is required for more efficient control of resistant populations. In this study, the quantitative sequencing (QS) protocols were established to detect the frequencies of three mutations (the L1014F on voltage sensitive sodium channel and the G119S and F331W on acetylcholinesterase 1) that are associated with either pyrethroids or organophosphates. Based on the QS protocol using newly designed non-polymorphic primers, resistance allele frequencies (RAFs) were estimated in field populations of An. sinensis, Cx. pipiens and Cx tritaeniorhynchus collected from an identical site in Korea. The dynamics of each resistance allele frequency over time in the same populations were also evaluated.
        45.
        2019.04 구독 인증기관·개인회원 무료
        A residual contact vial plus water (RCVpW) bioassay method was established to monitor insectiside resistance in field populations of the melon thrips, Thrips palmi. Resistance level against six major insecticides were evalutated in five regions to test applicability of RCVpW as an on-site resistance monitoring tool. Reduced mortality in response to six test insecticides were exhibited compared to the RDA susceptable strain showing 100 % mortality, indicating different degree of resistance. An apparently reduced mortality to emamectin benzoate and chlofenapyr was observed in some field populations, suggesting uneven distribution of resistance to these insecticides in field populations. In addition, spinosad resistance was high and widely distributed in the test regions. Synergistic bioassay revealed that cytochrome P450-mediated metabolic factor is involved in spinosad resistance in the Korean population.
        46.
        2019.04 구독 인증기관·개인회원 무료
        One of major mechanisms of insecticide resistance is the reduced susceptibility caused by mutations on the main target sites, such as sodium channel and acetylcholinesterase. Bioassay is a useful method to diagnose insecticide resistance of mosquitoes; however, it is hard to establish regional/annual resistance database based on bioassay. Recently, various markers of mutation and copy number variation have been identified through insecticide mechanism studies. Thus, molecular detection of resistance based on the resistance marker is now feasible, which can be readily implemented as a novel resistance monitoring tool to complement or replace the conventional bioassay method. In Korea, the density of vector mosquitoes native to the subtropical areas has increased due to climate change. Therefore, it is required to establish an efficient resistance monitoring system based on molecular markers to facilitate the construction of a nation-wide resistance map for more effective control of mosquitos. In addition, alternative insecticides should be introduced to the areas where mosquitoes develop high levels of resistance to maximize control efficacy against resistant populations
        47.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 중앙 아시아는 5 개의 국가로 구성되어 있으며, 이 국가들은 1991년에 소련 연방에서 독립하였다. 독립 이전에는 5개 국가 모두 공산주의 통치 하에 동일한 소비에트 계획경제 체제를 가지고 있었다 2. 1991년 이래로 중앙 아시아 국가들은 정치적, 사회적, 자연적, 지리적 조건에 따라 각기 다른 개발 경로를 경험하였다. 3. 더 나은 통치 환경은 현대 기술 혁신을 장려하고 토지에 대한 신기술의 적용 및 토지에 대한 권리를 보장하도록 동기를 부여한다. 또한 상대적으로 낮은 거래 비용이 조성될 수 있도록 지원하여 생산 증대로 이어질 투자를 촉진한다. 4. 따라서 통치 환경의 개선은 농업 생산 증대에도 중요한 요인이다. 본 연구는 통치 환경과 농업 생산과의 관계를 실증적으로 분석하고 이를 검증하였다. 5. 본 연구의 결과는 농업 생산의 증대를 위하여 통치 환경의 개선이 중요함을 입증하였으며 , 그 중에서도 부패 통제 및 법의 지배의 개선이 농업 생산 증대에 가장 큰 영향을 미친다는 것을 밝혔다 .
        4,000원
        48.
        2018.10 구독 인증기관·개인회원 무료
        The honey bee soluble acetylcholinesterase 1 (AmAChE1) is overexpressed under the overwintering and brood rearing-suppressed conditions. To investigate the role of AmAChE1 in regulating acetylcholine (ACh) titer, ACh concentrations both in the head (neuronal) and abdomen (non-neuronal) were analyzed. ACh titer was significantly lower in both tissues of worker bees under the overwintering and brood rearing-suppressed conditions compared to control bees. The expression levels of another two factors that regulate ACh titer, choline acetyltransferase (AmAChT) and acetylcholinesterase 2 (AmAChE2), were not altered as judged by qPCR and native PAGE, suggesting that the lower ACh titer was mainly regulated by AmAChE1. For precise verification of AmAChE1 as an ACh titer regulator, honey bees were put under brood rearing-suppressed condition to induce AmAChE1 and injected AmAChE1 dsRNA to knock down the gene. The ACh titer of AmAChE1-knocked down honey bees was 1.9 and 2.6 folds higher than that of control bees in head and abdomen, respectively. Taken together, in spite of its extremely low catalytic activity, the overexpression of AmAChE1 is likely to be related with the low level of ACh homeostasis, perhaps via ACh sequestration, under brood rearingsuppressed condition, and likely induce metabolic changes through ACh receptors-related pathways.
        49.
        2018.05 구독 인증기관·개인회원 무료
        To be better fit for highways, pavement systems are required to provide comfortable and safe driving and be structurally durable. Composite pavements can be an effective option as they are more durable by placing a high functional asphalt overlay on a rigid concrete base layer. In order to apply a composite pavement system to the field, it is necessary not only to develop technologies that prevent reflecting crack and deterioration of the base layer, but also to improve bonding performance of materials and ensure structural performance as a pavement system against traffic loading. In advanced countries like Japan, USA and Europe, high-functional composite pavement systems are being put into practice across new highway networks. In this study, we evaluated structural performance (rutting, reflecting crack, and deflection) by applying traffic loads of actual highways through an accelerated pavement tester (APT) of a composite pavement section made up of a quiet porous surface laid over a water-proofing layer, a continuously reinforced concrete base, and a lean concrete sub-base layer, which was developed with new pavement methods used for each layer prior to field application. The APT specimen was constructed with paving materials and equipment actually used on site in the same dimensions (W3.5m*L14m*H2m) as actual highway sections in Korea, and 3-axle double-wheel heavy load (45ton) cart type KALES(Korean Accelerated Loading and Environmental Simulator) traveling on the specimen in both directions was used to simulate traffic loading. After applying around 8,574,000 ESALs of traffic loads, no reflecting crack occurred on the asphalt surface of the composite pavement, without surface distress except for rutting. In order to examine what causes rutting of pavements, we surveyed thickness of pavements by layer and measured asphalt density.
        50.
        2018.05 구독 인증기관·개인회원 무료
        Some of the deicer ingredients are the same as fertilizer ingredients from agricultural activities. The goal of this study is to distinguish the components of highway deicer from the components used for agriculture. Among the deicer ingredients, Ca and Cl are substances which can be supplied by fertilizer or livestock manure. However, fertilizer and livestock manure contain plenty of nitrogen, organic matter, phosphoric acid and magnesium, including deicer ingredients. The soil physico-chemical characteristics were analyzed according to the distance from the highway. The physico-chemical analysis items of the soil include electrical conductivity, total nitrogen (TN), available phosphate (Av.P), organic matter (OM), ammonia nitrogen (NH4-N), Cation Exchange Capacity (CEC). In the case of effective phosphoric acid, leaching into the subsoil is very low due to various binding mechanisms in the soil. However, it is considered that the compost (fertilizer) applied to the topsoil is mixed with the soil by the tillage or flattening operation. In addition to the organic matter content of the subsoil appear to 10% or more is that in some cases exhibit a similar level as the topsoil. The average soil organic matter content of about 2.6%. This results shows that an excess of organic compost in the study area flows into subsoil and was mixed with the subsoil. The high EC value at the points outside the snow removal effect range level is not considered to be affected by the deicer. The results of the survey showed that the values were differently detected by agricultural activities, and that they should be approached in a complex way in their interpretation.
        51.
        2018.04 구독 인증기관·개인회원 무료
        Small hive beetle (Aethina tumida) (SHB) is an invasive species to most northern hemisphere countries, including Korea. In an attempt to obtain basic information for efficient management of SHB, genes encoding conventional insecticide targets [voltage-sensitive sodium channel α-subunit (VSSC) and acetylcholinesterase (AChE)] were annotated and characterized following the analysis of whole transcriptomes of adults and larvae. A single VSSC gene was identified but no apparent mutations associated with pyrethroid resistance were detected. Genes encoding two AChEs (AtAChE1 and AtAChE2) were identified from the SHB transcriptome. AtAChE1 was determined to be the main catalytic enzyme, thereby being a toxicologically more relevant target. No apparent mutations associated with resistance to organophosphorus and carbamate insecticides was identified in the AtAChE1 gene, whereas the S238G mutation, originally identified from the Colorado potato beetle, was detected in the AtAChE2 gene.
        52.
        2018.04 구독 인증기관·개인회원 무료
        The common bed bug, Cimex lectularius, possesses a cholinesterase expressed exclusively in the salivary gland (ClSChE). In this paper, we investigated the molecular structure, tissue distribution patterns, and biochemical properties of ClSChE and showed that ClSChE exists as a soluble monomeric form or a soluble dimeric form connected by a disulfide bridge. Immunohistochemical analysis confirmed that ClSChE was expressed in the epithelial cells of both the salivary gland and the duct. In addition, the secretion of monomeric ClSChE through the proboscis during feeding was detected by western blotting using a ClSChE-specific antibody. To predict the role of ClSChE injected into the tissue of an animal host, we analyzed the extent of sequestration and hydrolysis of acetylcholine (ACh)/choline (Ch) by ClSChE by ultra-performance liquid chromatography-tandem mass spectrometry. Kinetic analysis revealed that ClSChE possesses extremely low Km (high affinity to ACh) and Vmax values. These findings suggest that ClSChE functions as a sequestering enzyme specific to ACh (not to Ch) by having a very strong affinity to ACh but an extremely long turnover time.
        53.
        2018.04 구독 인증기관·개인회원 무료
        The honey bee soluble acetylcholinesterase 1 (AmAChE1) is overexpressed under the overwintering and brood rearing-suppressed conditions. To investigate the role of AmAChE1 in regulating acetylcholine (ACh) titer, ACh concentrations in both the head (central nervous system) and abdomen (peripheral nervous system) were analyzed. ACh titer was significantly lower in both tissues of worker bees under the overwintering and brood rearing-suppressed conditions compared to control bees. Interestingly, the expression levels of choline acetyltransferase (AmChAT) and molecular marker genes of immune systems were significantly reduced in honey bee head under the same conditions. Taken together, ACh titer appears to be reduced via a cooperative interaction of the AmAChE1 overexpression and AmChAT underexpression and to be linked to reduced inmmune responses under the overwintering and brood rearing-suppressed conditions. The roles of AmAChE1 (with little catalytic activity) and AmChAT in the ACh homeostasis and signaling was discussed in the contexts of immune response and longevity regulation in honey bees.
        54.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the production of zirconium cladding tube, a pickling acid solution is used to remove surface contaminants, which generates tons of pickling acid waste. The waste pickling solution is a valuable resource of Hf-free Zr. Many studies have investigated separating the Hf-free Zr source from the waste pickling acid. The results showed that Ba2ZrF8 precipitates prepared from the waste pickling acid were useful as an electrolyte for the electrorefining of Zr in molten salt. In the present work, electrorefining was performed in a Ba2ZrF8-LiF binary electrolyte to recover Zr from a Hf-free CuZr ingot anode prepared by electroreduction. Before electrorefining, two pretreatments are performed. First, electrolyte melting was carried out to determine the eutectic temperature, and second, the electrolyte was treated to eliminate impurities, mainly hydride. After electrorefining, the cathode deposits were analyzed by O2 gas analyzer and SEM-EDX to explore the possibility of recovering nuclear-grade Zr metal. Moreover, the anode was analyzed by SEM-EDX to determine the Zr dissolution depth.
        4,000원
        55.
        2017.10 구독 인증기관·개인회원 무료
        Among two different acetylcholinesterase (AmAChE1 and AmAChE2) of the western honey bee, the soluble AmAChE1might be related with a stress response as judged from its over-expression in honey bee workers when brood rearingwas suppressed. In this study, to ensure the nature of AmAChE1 responding to stress factors, the expression patternsof AmAChE1 were investigated following various treatments, including varroa mite infestation, bacterial challenge, broodrearing suppression, thermal stresses, chemical treatments, ultraviolet B irradiation, starvation, water restriction and crowdingstress. In addition, transcription profiles of four heat shock protein genes known as general stress markers and vitellogeningene, which is induced in several stress conditions, were tested as positive references. In every tested condition, onlybrood rearing suppression and heat shock were related with the expression of AmAChE1.
        56.
        2017.04 구독 인증기관·개인회원 무료
        Honey bee swarming is a natural phenomenon that occurs by changes of colony (i.e. population size and queen condition) and environment conditions. As cuticular hydrocarbons (CHCs) are known to be involved in the communication between honey bee nest-mates, we investigated and compared the CHC profiles of worker bees from individual colonies of 9-days before swarming (PPSC), a day before swarming (PSC), swarming (SG) and remaining (non-swarming) (RG). A total of 53 CHCs were identified by GC-MS, among which 11 compounds showed significantly differential expression patterns between swarming states. Before swarming (between PPSC and PSC), detection levels of 4 CHCs were significantly different, suggesting that production of some CHCs changed prior to swarming for swarming preparation. Six CHCs were deferentially produced between PSC and RG. The differential profiles of CHCs with respect to different swarming states are currently under investigation.
        57.
        2017.04 구독 인증기관·개인회원 무료
        Perturbation of normal behaviors (e.g., nursing and foraging) in honey bee colonies by any external factors would immediately reduce the colony’s capacity for brood rearing, which can eventually lead to collapse of entire colony. To investigate the effects of brood rearing suppression in the biology of honey bee workers (nurse and forager), the gene-set enrichment analysis (GSEA) was performed for the transcriptomes of worker bees with or without their brood rearing being suppressed, from which functional profiles of pathways under influences by each condition were identified. Blocking of normal labor (i.e., nursing or foraging) induced the over-representation of pathways related with reshaping of worker bee physiology, suggesting that transition of labor is physiologically reversible. In addition, brood rearing suppression appeared to result in the reduction of neuronal excitability and aggressiveness in both forager and nurse, which would be necessary to manage the in-hive stress under unfavorable conditions
        58.
        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.
        59.
        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.
        60.
        2016.10 구독 인증기관·개인회원 무료
        Honey bee swarming is a natural phenomenon that occurs when the colony encounters changes in the in-hive (i.e. population size and queen condition) and environmental conditions. To better understand the molecular basis of swarming, we conducted the transcriptomic profiles of worker bees between before swarming [pre-swarming colony (PSC)] and after swarming [swarming group (SG) and remaining group (RG)]. Based on the gene set enrichment analysis (GSEA), we predicted the biological processes associated with swarming. In addition, we analyzed the composition of cuticular hydrocarbons (CHCs) by gas chromatography-mass spectrometry and compared their profiles between different bee groups. GSEA results showed that there were a little differences between PSC and RG while many of the pathways related with metabolism and protein processing were down regulated in SG relative to PSC and RG. CHCs profiling revealed a similar CHCs composition between PSC and RG but some differences in CHCs composition (i.e. heneicosane, octacosane, octacosanol) were detected between SG and RG. These differences in gene pathway and CHC composition were discussed with respect to physiological changes and social communication.
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