903 research outputs found

    Action Spectrum for Phototherapy of Psoriasis

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    Using a monochromator the action spectrum for ultraviolet phototherapy of psoriasis was determined for radiation between 254 and 313nm and compared to the action spectrum for erythema of uninvolved adjacent skin. Daily exposures of different doses of 254, 280, 290, 296, 300, 304 and 313nm radiation were observed. Wavelengths of 254, 280, and 290nm were erythemogenic but not therapeutic even at 10 to 50 times the minimal erythema dose. At the other wavelengths studied, the 2 action spectra were similar. In general, fixed daily doses cleared at lower cumulative dose than did incrementally increased daily doses. The small number of suberythemogenic exposure doses required suggests that monochromatic radiation may have advantages over broadband sources

    Hydrological restoration of Indonesian peatlands to mitigate carbon dioxide emissions

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    Delta Session DS 9: The lowland deltas of Indonesia. Hydrological restoration of Indonesian peatlands to mitigate carbon dioxide emissions, Henk Wösten (2010). Presented at the international conference Deltas in Times of Climate Change, 29 September - 1 October, Rotterdam, the Netherlands

    Elastic Tensor of YNi_2B_2C

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    The complete elastic tensor of YNi_2B_2C was determined by application of the resonant ultrasound spectroscopy technique to a single-crystal sample. Elastic constants were found to be in good agreement with partial results obtained from `time-of-flight' measurements performed on samples cut from the same ingot. From the measured constants, the bulk modulus and Debye temperature are calculated.Comment: 5 pages, 3 figure

    Discrete molecular dynamics simulations of peptide aggregation

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    We study the aggregation of peptides using the discrete molecular dynamics simulations. At temperatures above the alpha-helix melting temperature of a single peptide, the model peptides aggregate into a multi-layer parallel beta-sheet structure. This structure has an inter-strand distance of 0.48 nm and an inter-sheet distance of 1.0 nm, which agree with experimental observations. In this model, the hydrogen bond interactions give rise to the inter-strand spacing in beta-sheets, while the Go interactions among side chains make beta-strands parallel to each other and allow beta-sheets to pack into layers. The aggregates also contain free edges which may allow for further aggregation of model peptides to form elongated fibrils.Comment: 15 pages, 8 figure

    Momentum-Dependent Mean Field Based Upon the Dirac-Brueckner Approach for Nuclear Matter

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    A momentum-dependent mean field potential, suitable for application in the transport-model description of nucleus-nucleus collisions, is derived in a microscopic way. The derivation is based upon the Bonn meson-exchange model for the nucleon-nucleon interaction and the Dirac-Brueckner approach for nuclear matter. The properties of the microscopic mean field are examined and compared with phenomenological parametrizations which are commonly used in transport-model calculations.Comment: 15 pages text (RevTex) and 4 figures (postscript in a separate uuencoded file), UI-NTH-930

    On the Divergence of Perturbation Theory. Steps Towards a Convergent Series

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    The mechanism underlying the divergence of perturbation theory is exposed. This is done through a detailed study of the violation of the hypothesis of the Dominated Convergence Theorem of Lebesgue using familiar techniques of Quantum Field Theory. That theorem governs the validity (or lack of it) of the formal manipulations done to generate the perturbative series in the functional integral formalism. The aspects of the perturbative series that need to be modified to obtain a convergent series are presented. Useful tools for a practical implementation of these modifications are developed. Some resummation methods are analyzed in the light of the above mentioned mechanism.Comment: 42 pages, Latex, 4 figure

    An Introductory Guide to Aligning Networks Using SANA, the Simulated Annealing Network Aligner.

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    Sequence alignment has had an enormous impact on our understanding of biology, evolution, and disease. The alignment of biological networks holds similar promise. Biological networks generally model interactions between biomolecules such as proteins, genes, metabolites, or mRNAs. There is strong evidence that the network topology-the "structure" of the network-is correlated with the functions performed, so that network topology can be used to help predict or understand function. However, unlike sequence comparison and alignment-which is an essentially solved problem-network comparison and alignment is an NP-complete problem for which heuristic algorithms must be used.Here we introduce SANA, the Simulated Annealing Network Aligner. SANA is one of many algorithms proposed for the arena of biological network alignment. In the context of global network alignment, SANA stands out for its speed, memory efficiency, ease-of-use, and flexibility in the arena of producing alignments between two or more networks. SANA produces better alignments in minutes on a laptop than most other algorithms can produce in hours or days of CPU time on large server-class machines. We walk the user through how to use SANA for several types of biomolecular networks
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