677 research outputs found

    Synthesis, characterization, anion complexation and electrochemistry of cationic Lewis acids

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    Owing to the favored Coulombic attraction between the ammonium group and anion which stabilizes the B-F/B-CN bond against heterolysis, cationic borane [25]+ has great affinity toward anions than its neutral analog, and is capable of capturing fluoride or cyanide from water under bi-phasic conditions. By placing the fluorophilic silyl group adjacent to an electrophilic carbocation, a novel fluoride sensor [45]+ was obtained. Sensing occurs via a fluoride induced methyl migration from the silicon to adjacent electrophilic methylium center which is unprecedented. As a result of its strong fluoride affinity, [45]+ is able to react with KF in aqueous media at pH 7.0. The electrochemistry study of these cationic Lewis boranes reveals that the cationic character of these boranes serves to decrease their reduction potential and increase the stability of the resulting radicals. In this part of the research, we have prepared a cationic borane [27]+, which features two reversible reduction waves at -0.86 and -1.56 (vs. Fc/Fc+) corresponding to the formation of stable neutral and anionic derivatives. The one-electron reduction of [27]+ leads to the formation of a boron containing neutral radical featuring an unusual boron-carbon one-electron π bond. Further reduction of 27• results in the formation of the borataalkene derivative [27]-, which features a formal B=C double bond. The structural changes accompanying the stepwise population of the B-C π-bond are also determined, and this sequential population of B-C π-bonding orbital is also supported by theoretical computations. In order to understand the impact of the cationic nature of these boranes on their oxidative power, three novel cationic boranes ([34]+, [35]2+, and [36]3+) have been synthesized and their oxidative power were examined via cyclic voltammetry. The CV data of these compounds shows that the reduction potential of these triarylboranes is linearly proportional to the number of the pendant cationic substituents. Substitution of a mesityl group by an ArN+ group leads to an increase of the reduction potential by 260 mV

    Classifying and Predicting Respiratory Function Based on Gait Analysis

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    The human walking behaviour can express the physiological information of human body, and gait analysis methods can be used to access the human body condition. In addition, the respiratory parameters from pulmonary spirometer are the standard of accessing the body condition of the subjects. Therefore, we want to show the correlation between gait analysis method and the respiratory parameters. We propose a vision sensor-based gait analysis method without wearing any sensors. Our method proposed features such as D′p, V′p and γυ to prove the correlation by classification and prediction experiment. In our experiment, the subjects are divided into three levels depending on the respiratory index. We run classifying and predicting experiment with the extracted features: V′p and γυ. In the classifying experiment, the accuracy result is 75%. In predicting experiment, the correlations of predicting the forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) are 0.69 and 0.67, respectively. Therefore, there is a correlation between the pulmonary spirometer and our method. The radar system is a tool using impulse to record the moving of the subjects’ chest. Combining the features of radar system with our features improves the classification result from 75 to 81%. In predicting FEV1/FVC, the correlation also improves from 25 to 42%. Therefore, cooperating with radar system improves the correlation

    RESEARCH ON THE MARKETING AND PUBLIC RELATIONS EFFECT AND SPORT EVENT SATISFACTION OF THE TAIPEI 2017 UNIVERSIADE

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    The purpose of this study is to investigate the spectators’ marketing and public relations and sport event satisfaction with their participation in the Taipei 2017 Universiade. Meanwhile, based on the comparison of different personal background variables, this study compares the attractiveness and satisfaction of the spectators’ marketing and public relations recognition, marketing and public relations attitude, event planning and sport event services. A random sampling method is adopted in this study. Among spectators, university students of the Taipei 2017 Universiade are selected. A total of 700 questionnaires are distributed and 680 valid questionnaires are collected. The effective recovery rate is 97.14%. The research tool of this study is “Satisfaction scale of marketing and public relations effect and sport event satisfaction of the Taipei 2017 Universiade”. This study uses statistical methods such as descriptive statistics, independent sample t-tests, and so forth. The results of this study are: (1) In the Taipei 2017 Universiade, spectators have the highest attractiveness with “Internet” in “media tools” of marketing and public relations recognition, followed by the factor of “TV”; (2) In “marketing and public relations attitude” of the Taipei 2017 Universiade, “marketing and public relations present efforts and earnest of Taiwan” ranks the highest, followed by “marketing and public relations are impressed”; (3) In “sport event services” of the Taipei 2017 Universiade, “auditorium” ranks the highest, followed by “broadcast notification”; (4) There is no significant difference in the attractiveness and satisfaction among spectators with different personal background for “marketing and public relations recognition”, “marketing and public relations attitude”, and “sport event services” in the Taipei 2017 Universiade.  Article visualizations

    The Dual-mediation Effect of Perceived Accuracy and Perceived Connectedness on Consumer Attitude Toward Social Network Advertising

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    Despite the importance of social media advertising, few studies have investigated the factors that influence its effectiveness (Jung, Shim, Jin, and Khang 2016). Because advertising on social media is a relatively new phenomenon (Okazaki and Taylor 2013), several studies are exploratory in nature and lack a solid theoretical framework (e.g., Campbell, Pitt, Parent, and Berthon 2011; Pehlivan, Sarican, and Berthon 2011; Sashittal, Sriramachandramurthy, and Hodis 2012; Waters and Jones 2011). For this reason, the present study examines the factors affecting consumers’ attitudes toward advertisements they view on social media. This paper draws on the stimulus-organism-response (S-O-R) model to investigate the dual mediation effect of perceived accuracy and perceived connectedness between endorsement from satisfied customers/review credibility/social influence and consumers’ attitudes toward social network advertising. Analysis of 1,031 valid responses to a survey show that endorsement from satisfied customers, review credibility, and social influence are antecedents of perceived accuracy and perceived connectedness. These variables are also antecedents of consumers’ attitudes toward social network advertising. In turn, perceived accuracy and connectedness partially mediate the relationships between endorsement from satisfied customers/review credibility/social influence and consumers’ attitudes toward social network advertising

    Maintaining the structural integrity of thebamboo mosaic virus 3′ untranslated region isnecessary for retaining the catalytic constant forminus-strand RNA synthesis

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    Background: Bamboo mosaic virus (BaMV) and the Potato virus X (PVX) are members of the genus Potexvirus andhave a single-stranded positive-sense RNA genome. The 3′-untranslated region (UTR) of the BaMV RNA genomewas mapped structurally into ABC (a cloverleaf-like), D (a stem-loop), and E (pseudoknot) domains. The BaMVreplicase complex that was isolated from the infected plants was able to recognize the 3′ UTR of PVX RNA toinitiate minus-strand RNA synthesis in vitro.Results: To investigate whether the 3′ UTR of PVX RNA is also compatible with BaMV replicase in vivo, weconstructed chimera mutants using a BaMV backbone containing the PVX 3′ UTR, which was inserted in or used toreplace the various domains in the 3′ UTR of BaMV. None of the mutants, except for the mutant with the PVX3′ UTR inserted upstream of the BaMV 3′ UTR, exhibited a detectable accumulation of viral RNA in Nicotianabenthamiana plants. The in vitro BaMV RdRp replication assay demonstrated that the RNA products were generatedby the short RNA transcripts, which were derived from the chimera mutants to various extents. Furthermore, theVmax/KM of the BaMV 3′ UTR (rABCDE) was approximately three fold higher than rABCP, rP, and rDE in minus-strandRNA synthesis. These mutants failed to accumulate viral products in protoplasts and plants, but were adequatelyreplicated in vitro.Conclusions: Among the various studied BaMV/PVX chimera mutants, the BaMV-S/PABCDE that containednon-interrupted BaMV 3′ UTR was the only mutant that exhibited a wild-type level of viral product accumulation inprotoplasts and plants. These results indicate that the continuity of the domains in the 3′ UTR of BaMV RNA wasnot interrupted and the domains were not replaced with the 3′ UTR of PVX RNA in vivo

    Pneumoureter

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    Local Periodicity-Based Beat Tracking for Expressive Classical Piano Music

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    To model the periodicity of beats, state-of-the-art beat tracking systems use "post-processing trackers" (PPTs) that rely on several empirically determined global assumptions for tempo transition, which work well for music with a steady tempo. For expressive classical music, however, these assumptions can be too rigid. With two large datasets of Western classical piano music, namely the Aligned Scores and Performances (ASAP) dataset and a dataset of Chopin's Mazurkas (Maz-5), we report on experiments showing the failure of existing PPTs to cope with local tempo changes, thus calling for new methods. In this paper, we propose a new local periodicity-based PPT, called predominant local pulse-based dynamic programming (PLPDP) tracking, that allows for more flexible tempo transitions. Specifically, the new PPT incorporates a method called "predominant local pulses" (PLP) in combination with a dynamic programming (DP) component to jointly consider the locally detected periodicity and beat activation strength at each time instant. Accordingly, PLPDP accounts for the local periodicity, rather than relying on a global tempo assumption. Compared to existing PPTs, PLPDP particularly enhances the recall values at the cost of a lower precision, resulting in an overall improvement of F1-score for beat tracking in ASAP (from 0.473 to 0.493) and Maz-5 (from 0.595 to 0.838).Comment: Accepted to IEEE/ACM Transactions on Audio, Speech, and Language Processing (July 2023

    Effects of natto extract on endothelial injury in a rat model

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    Vascular endothelial damage has been found to be associated with thrombus formation, which is considered to be a risk factor for cardiovascular disease. A diet of natto leads to a low prevalence of cardiovascular disease. The aim of the present study was to investigate the effects of natto extract on vascular endothelia damage with exposure to laser irradiation. Endothelial damage both in vitro and in vivo was induced by irradiation of rose bengal using a DPSS green laser. Cell viability was determined by MTS assay, and the intimal thickening was verified by a histological approach. The antioxidant content of natto extract was determined for the free radical scavenging activity. Endothelial cells were injured in the presence of rose bengal irradiated in a dose-dependent manner. Natto extract exhibits high levels of antioxidant activity compared with purified natto kinase. Apoptosis of laser-injured endothelial cells was significantly reduced in the presence of natto extract. Both the natto extract and natto kinase suppressed intimal thickening in rats with endothelial injury. The present findings suggest that natto extract suppresses vessel thickening as a synergic effect attributed to its antioxidant and anti-apoptosis properties
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