20,057 research outputs found

    A Survey on Multisensor Fusion and Consensus Filtering for Sensor Networks

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    Multisensor fusion and consensus filtering are two fascinating subjects in the research of sensor networks. In this survey, we will cover both classic results and recent advances developed in these two topics. First, we recall some important results in the development ofmultisensor fusion technology. Particularly, we pay great attention to the fusion with unknown correlations, which ubiquitously exist in most of distributed filtering problems. Next, we give a systematic review on several widely used consensus filtering approaches. Furthermore, some latest progress on multisensor fusion and consensus filtering is also presented. Finally, conclusions are drawn and several potential future research directions are outlined.the Royal Society of the UK, the National Natural Science Foundation of China under Grants 61329301, 61374039, 61304010, 11301118, and 61573246, the Hujiang Foundation of China under Grants C14002 and D15009, the Alexander von Humboldt Foundation of Germany, and the Innovation Fund Project for Graduate Student of Shanghai under Grant JWCXSL140

    Mapping the role of aromatic amino acids within a blue-light sensing LOV domain

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    Photosensing LOV (Light, Oxygen, Voltage) domains detect and respond to UVA/Blue (BL) light by forming a covalent adduct between the flavin chromophore and a nearby cysteine, via the decay of the flavin triplet excited state. LOV domains where the reactive cysteine has been mutated are valuable fluorescent tools for microscopy and as genetically encoded photosensitisers for reactive oxygen species. Besides being convenient tools for applications, LOV domains without the reactive cysteine (naturally occurring or engineered) can still be functionally photoactivated via formation of a neutral flavin radical. Tryptophans and tyrosines are held as the main partners as potential electron donors to the flavin excited states. In this work, we explore the relevance of aromatic amino acids in determining the photophysical features of the LOV protein Mr4511 from Methylobacterium radiotolerans by introducing point mutations into the C71S variant that does not form the covalent adduct. By using an array of spectroscopic techniques we measured the fluorescence quantum yields and lifetimes, the triplet yields and lifetimes, and the efficiency of singlet oxygen (SO) formation for eleven Mr4511 variants. Insertion of Trp residues at distances between 0.6 and 1.5 nm from the flavin chromophore results in strong quenching of the flavin excited triplet state and, at the shorter distances even of the singlet excited state. The mutation F130W (ca. 0.6 nm) completely quenches the singlet excited state, preventing triplet formation: in this case, even if the cysteine is present, the photo-adduct is not formed. Tyrosines are also quenchers for the flavin excited states, although not as efficient as Trp residues, as demonstrated with their substitution with the inert phenylalanine. For one of these variants, C71S/Y116F, we found that the quantum yield of formation for singlet oxygen is 0.44 in aqueous aerobic solution, vs 0.17 for C71S. Based on our study with Mr4511 and on literature data for other LOV domains we suggest that Trp and Tyr residues too close to the flavin chromophore (at distances less than 0.9 nm) reduce the yield of photoproduct formation and that introduction of inert Phe residues in key positions can help in developing efficient, LOV-based photosensitisers. This journal i

    Raman frequency shift in oxygen functionalized carbon nanotubes

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    In terms of lattice dynamics theory, we study the vibrational properties of the oxygen-functionalized single wall carbon nanotubes (O-SWCNs). Due to the C-O and O-O interactions, many degenerate phonon modes are split and even some new phonon modes are obtained, different from the bare SWCNs. A distinct Raman shift is found in both the radial breathing mode and G modes, depending not only on the tube diameter and chirality but also on oxygen coverage and adsorption configurations. With the oxygen coverage increasing, interesting, a nonmonotonic up- and down-shift is observed in G modes, which is contributed to the competition between the bond expansion and contraction, there coexisting in the functionalized carbon nanotube.Comment: 4 pages, 3 figures, 1 tabl

    Evaluating the semantic web: a task-based approach

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    The increased availability of online knowledge has led to the design of several algorithms that solve a variety of tasks by harvesting the Semantic Web, i.e. by dynamically selecting and exploring a multitude of online ontologies. Our hypothesis is that the performance of such novel algorithms implicity provides an insight into the quality of the used ontologies and thus opens the way to a task-based evaluation of the Semantic Web. We have investigated this hypothesis by studying the lessons learnt about online ontologies when used to solve three tasks: ontology matching, folksonomy enrichment, and word sense disambiguation. Our analysis leads to a suit of conclusions about the status of the Semantic Web, which highlight a number of strengths and weaknesses of the semantic information available online and complement the findings of other analysis of the Semantic Web landscape
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