1,052 research outputs found

    Effects of different ceramic and dentin thicknesses on the temperature rise during photocuring

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    AbstractBackground/purposeThe aims of this investigation were to describe the effect of different ceramic and remaining dentin thicknesses on substrate temperature during photocuring, and investigate whether the temperature increased by >5.5°C for different dentin/ceramic combinations.Materials and methodsThree groups of dentin thicknesses of 1.0 (D1.0), 1.5 (D1.5), and 2.0 mm (D2.0), and three groups of ceramic thicknesses of 1.5 (C1.5), 2.5 (C2.5), and 3.5 mm (C3.5) were examined. Temperature changes and the maximum temperature were observed under a high-intensity halogen light (QTH-Atralis 10 ECS program at 1200mW/cm2 for 30 seconds, Ivoclar Vivadent AG, Schaan, Liechtenstein). Four groups, D1.0–C1.5 (+11°C), D1.5–C1.5 (+7.2°C), D1.0–C2.5 (+6.7°C), and D2–0C1.5 (+5.8°C), demonstrated temperature changes of >5.5°C.Results and ConclusionsA statistical analysis showed that separate individual thicknesses and combinations of dentin and ceramic had significant effects on temperature changes (P<0.01). It was observed that the ceramic exhibited a smaller temperature shielding effect than dentin. Clinically, it would be optimal to preserve the dentin to avoid damaging pulp tissues. Where there is insufficient overall thickness (≤3.5mm), continuous high-energy output photocuring should be avoided to protect pulp tissues from thermal injury

    Preparation, characterization, and application of titanium nano-tube array in dye-sensitized solar cells

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    The vertically orientated TiO2 nanotube array (TNA) decorated with TiO2 nano-particles was successfully fabricated by electrochemically anodizing titanium (Ti) foils followed by Ti-precursor post-treatment and annealing process. The TNA morphology characterized by SEM and TEM was found to be filled with TiO2 nano-particles interior and exterior of the TiO2 nano-tubes after titanium (IV) n-butoxide (TnB) treatment, whereas TiO2 nano-particles were only found inside of TiO2 nano-tubes upon titanium tetrachloride (TiCl4) treatment. The efficiency in TNA-based DSSCs was improved by both TnB and TiCl4 treatment presumably due to the increase of dye adsorption

    (Mis)perception of Party Congruence and Satisfaction with Democracy

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    This study investigates the implications of perceived ideological incongruence between voters and their supported parties for satisfaction with democracy. Using panel data from the British Election Study, we first demonstrate that greater misperceptions of party positions correspond to higher perceived ideological distance from one’s preferred party. We then show that such increased perceived incongruence is associated with reduced satisfaction with democracy, even when accounting for actual incongruence based on expert surveys of party positions. This pattern is also seen when using several alternative measures and specifications, as well as in cross-sectional data from Europe. The findings suggest subjective perceptions of representation, potentially distorted by misperceptions, play a role in how ideological congruence relates to citizen attitudes toward the political system. While potential endogeneity warrants caution in interpreting the relationship, the results suggest that potentially inaccurate beliefs about parties can distort the link between representation and satisfaction with democratic performance

    Examining the Antecedents of Repurchase Intention in Convenience Stores: A Perspective of Expectation-Disconfirmation Theory

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    The density of convenience stores in Taiwan is the highest in the world. In a convenience store context, this study attempts to examine the relationship between service quality, customer satisfaction and repurchase intention, as well as the impact of customer familiarity with employees on customer satisfaction and repurchase intention. The result indicated that expectation had direct effect on service quality. The result also showed that service quality was positively related to disconfirmation. As expected, there were interrelationships among service quality, satisfaction, and repurchase intention. Moreover, customer familiarity with employees had positive, direct influence on both satisfaction and repurchase intentions

    An Outbreak of Coxsackievirus A16 Infection: Comparison With Other Enteroviruses in a Preschool in Taipei

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    Background/PurposeThe transmission rate of enteroviruses in young children remains unclear. Therefore, we carried out active surveillance in preschool children to investigate the transmission rate and clinical manifestation of enteroviruses.MethodsFrom September 2006 to December 2008, we monitored infectious diseases in children 2(–3 years of age) in a preschool in Taipei. If any child had a febrile illness or symptoms/signs of enteroviral infection [e.g. herpangina or hand-foot-and-mouth disease (HFMD)], we performed viral isolation and enterovirus polymerase chain reaction. VP1 sequencing was performed to define their serotypes. We also collected clinical data and analyzed transmission rates.ResultsThere were eight episodes of enterovirus infection during the study period. The serotypes included coxsackievirus A4 (CA4), CA2 and CA16. The transmission rates of CA4 and CA2 among children in same class were 26% and 35%, respectively. Between November 28 and December 12, 2008, 13/21 (61.9%) children contracted herpangina and/or HFMD. The average age was 2.82 (range, 2.43–3.39) years. CA16 was detected in 10/13 (76.9%) of the throat swabs by polymerase chain reaction VP1 genotyping. Compared with previous CA2 and CA4 outbreaks, CA16 had a significantly higher transmission rate (p = 0.035) and resulted in more cases of HFMD (p < 0.001). The transmission duration of coxsackie A viruses within the same class ranged from 12 to 40 days.ConclusionCompared with CA2 and CA4, CA16 infections resulted in more cases of HFMD and had significantly higher transmission rates in preschoolers

    Resveratrol retards progression of diabetic nephropathy through modulations of oxidative stress, proinflammatory cytokines, and AMP-activated protein kinase

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    <p>Abstract</p> <p>Background</p> <p>Diabetic nephropathy (DN) has been recognized as the leading cause of end-stage renal disease. Resveratrol (RSV), a polyphenolic compound, has been indicated to possess an insulin-like property in diabetes. In the present study, we aimed to investigate the renoprotective effects of RSV and delineate its underlying mechanism in early-stage DN.</p> <p>Methods</p> <p>The protective effects of RSV on DN were evaluated in streptozotocin (STZ)-induced diabetic rats.</p> <p>Results</p> <p>The plasma glucose, creatinine, and blood urea nitrogen were significantly elevated in STZ-induced diabetic rats. RSV treatment markedly ameliorated hyperglycemia and renal dysfunction in STZ-induced diabetic rats. The diabetes-induced superoxide anion and protein carbonyl levels were also significantly attenuated in RSV-treated diabetic kidney. The AMPK protein phosphorylation and expression levels were remarkably reduced in diabetic renal tissues. In contrast, RSV treatment significantly rescued the AMPK protein expression and phosphorylation compared to non-treated diabetic group. Additionally, hyperglycemia markedly enhanced renal production of proinflammatory cytokine IL-1β. RSV reduced IL-1β but increased TNF-α and IL-6 levels in the diabetic kidneys.</p> <p>Conclusions</p> <p>Our findings suggest that RSV protects against oxidative stress, exhibits concurrent proinflammation and anti-inflammation, and up-regulates AMPK expression and activation, which may contribute to its beneficial effects on the early stage of DN.</p

    POWER: PhylOgenetic WEb Repeater—an integrated and user-optimized framework for biomolecular phylogenetic analysis

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    POWER, the PhylOgenetic WEb Repeater, is a web-based service designed to perform user-friendly pipeline phylogenetic analysis. POWER uses an open-source LAMP structure and infers genetic distances and phylogenetic relationships using well-established algorithms (ClustalW and PHYLIP). POWER incorporates a novel tree builder based on the GD library to generate a high-quality tree topology according to the calculated result. POWER accepts either raw sequences in FASTA format or user-uploaded alignment output files. Through a user-friendly web interface, users can sketch a tree effortlessly in multiple steps. After a tree has been generated, users can freely set and modify parameters, select tree building algorithms, refine sequence alignments or edit the tree topology. All the information related to input sequences and the processing history is logged and downloadable for the user's reference. Furthermore, iterative tree construction can be performed by adding sequences to, or removing them from, a previously submitted job. POWER is accessible at

    Does Long-Term Use of Silver Nanoparticles Have Persistent Inhibitory Effect on H. pylori Based on Mongolian Gerbil’s Model?

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    It is urgent to find alternative agents due to increasing failure rate of Helicobacter pylori (H. pylori) eradication. The study surveyed the long-term effect of silver nanoparticles (AgNP) on H. pylori based on Mongolian gerbil's model

    Secure Adaptive Topology Control for Wireless Ad-Hoc Sensor Networks

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    This paper presents a secure decentralized clustering algorithm for wireless ad-hoc sensor networks. The algorithm operates without a centralized controller, operates asynchronously, and does not require that the location of the sensors be known a priori. Based on the cluster-based topology, secure hierarchical communication protocols and dynamic quarantine strategies are introduced to defend against spam attacks, since this type of attacks can exhaust the energy of sensor nodes and will shorten the lifetime of a sensor network drastically. By adjusting the threshold of infected percentage of the cluster coverage, our scheme can dynamically coordinate the proportion of the quarantine region and adaptively achieve the cluster control and the neighborhood control of attacks. Simulation results show that the proposed approach is feasible and cost effective for wireless sensor networks

    Wafer-scale growth of large arrays of perovskite microplate crystals for functional electronics and optoelectronics

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    Methylammonium lead iodide perovskite has attracted intensive interest for its diverse optoelectronic applications. However, most studies to date have been limited to bulk thin films that are difficult to implement for integrated device arrays because of their incompatibility with typical lithography processes. We report the first patterned growth of regular arrays of perovskite microplate crystals for functional electronics and optoelectronics. We show that large arrays of lead iodide microplates can be grown from an aqueous solution through a seeded growth process and can be further intercalated with methylammonium iodide to produce perovskite crystals. Structural and optical characterizations demonstrate that the resulting materials display excellent crystalline quality and optical properties. We further show that perovskite crystals can be selectively grown on prepatterned electrode arrays to create independently addressable photodetector arrays and functional field effect transistors. The ability to grow perovskite microplates and to precisely place them at specific locations offers a new material platform for the fundamental investigation of the electronic and optical properties of perovskite materials and opens a pathway for integrated electronic and optoelectronic systems.Comment: 8 pages, 4 figure
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