10,868 research outputs found

    Insights into DNA platination within unusual structural settings

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    2D [1H, 15N] HSQC NMR spectroscopy has been used to monitor reaction and product formation between [Pt(15NH3)2I2] and nucleic acids possessing irregular topologies and containing site specific phosphorothioate substitution in the phosphodiester backbone. Comparison of the reaction profiles of dimer nucleic acids with and without phosphorothioate substitution is made with their short nucleic acid counterparts containing the key dimer components. Whereas d(GpA) is relatively unreactive towards [Pt(15NH3)2I2], NMR evidence suggests that the tandem sheared mismatch duplex d(GCG3pAGC)2 reacts to form the head-to-tail inter-strand G3-N7-Pt-G3-N7 cross-link. The equivalent phosphorothioate R,S-d(GsA) reacts to form a mono-iodo, mono-sulphur adduct, whereas the tandem sheared mismatch phosphorothioate duplex d(GCGsAG5C)2 (VIs) reacts to form the unusual intra-strand macrochelate [Pt(15NH3)2{d(VIs-G5-N7)},S]2+ in which platinum is attached at both sulphur and G5-N7. Experimental evidence supports the formation of a stabilized mismatch duplex in which platinum is attached to two nitrogen centres in the sequence d(CGCGpTGCG) in contrast to R,S-d(CGCGsT5GCG) for which NMR evidence supports macrochelate-stabilized hairpin loop formation cross-linked at both phosphorothioate sulphur and T5-N

    Oceanographic influences on the sea ice cover in the Sea of Okhotsk

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    Sea ice conditions in the Sea of Okhotsk, as determined by satellite images from the electrically scanning microwave radiometer on board Nimbus 5, were analyzed in conjunction with the known oceanography. In particular, the sea ice coverage was compared with the bottom bathymetry and the surface currents, water temperatures, and salinity. It is found that ice forms first in cold, shallow, low salinity waters. Once formed, the ice seems to drift in a direction approximating the Okhotsk-Kuril current system. Two basic patterns of ice edge positioning which persist for significant periods were identified as a rectangular structure and a wedge structure. Each of these is strongly correlated with the bathymetry of the region and with the known current system, suggesting that convective depth and ocean currents play an important role in determining ice patterns

    Haptic Wave

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    We present the Haptic Wave, a device that allows cross-modal mapping of digital audio to the haptic domain, intended for use by audio producers/engineers with visual impairments. We describe a series of participatory design activities adapted to non-sighted users where the act of prototyping facilitates dialog. A series of workshops scoping user needs, and testing a technology mock up and lo-fidelity prototype fed into the design of a final high-spec prototype. The Haptic Wave was tested in the laboratory, then deployed in real world settings in recording studios and audio production facilities. The cross-modal mapping is kinesthetic and allows the direct manipulation of sound without the translation of an existing visual interface. The research gleans insight into working with users with visual impairments, and transforms perspective to think of them as experts in non-visual interfaces for all users. This received the Best Paper Award at CHI 2016, the most prestigious human-computer interaction conference and one of the top-ranked conferences in computer science

    OntoCAT - an integrated programming toolkit for common ontology application tasks

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    OntoCAT provides high level abstraction for interacting with ontology resources including local ontology files in standard OWL and OBO formats (via OWL API) and public ontology repositories: EBI Ontology Lookup Service (OLS) and NCBO BioPortal. Each resource is wrapped behind easy to learn Java, Bioconductor/R and REST web service commands enabling reuse and integration of ontology software efforts despite variation in technologies

    Palladium, platinum, and gold distribution in serpentinite seamounts in the Mariana and Izu-Bonin forearcs: evidence from Leg 125 fluids and serpentinites

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    Palladium, platinum, and gold were analyzed for 20 interstitial water samples from Leg 125. No Pd or Pt was detected in fluids from serpentinite muds from Conical Seamount in the Mariana forearc, indicating that low-temperature seawater-peridotite interaction does not mobilize these elements into the serpentinizing fluids to levels above 0.10 parts per billion (ppb) in solution. However, Au may be mobilized in high pH solutions. In contrast, fluids from vitric-rich clays on the flanks of the Torishima Seamount in the Izu-Bonin forearc have Pd values of between 4.0 and 11.8 nmol/L, Pt values between 2.3 and 5.0 nmol/L and Au values between 126.9 and 1116.9 pmol/L. The precious metals are mobilized, and possibly adsorbed onto clay mineral surfaces, during diagenesis and burial of the volcanic-rich clays. Desorption during squeezing of the sediments may produce the enhanced precious metal concentrations in the analyzed fluids. The metals are mobilized in the fluids probably as neutral hydroxide, bisulfide, and ammonia complexes. Pt/Pd ratios are between 0.42 and 2.33, which is much lower than many of the potential sources for Pt and Pd but is consistent with the greater solubility of Pd compared with Pt in most natural low-temperature fluids

    Palladium, platinum, and gold distribution in serpentinite seamounts in the Mariana and Izu-Bonin forearcs: evidence from Leg 125 fluids and serpentinites

    No full text
    Palladium, platinum, and gold were analyzed for 20 interstitial water samples from Leg 125. No Pd or Pt was detected in fluids from serpentinite muds from Conical Seamount in the Mariana forearc, indicating that low-temperature seawater-peridotite interaction does not mobilize these elements into the serpentinizing fluids to levels above 0.10 parts per billion (ppb) in solution. However, Au may be mobilized in high pH solutions. In contrast, fluids from vitric-rich clays on the flanks of the Torishima Seamount in the Izu-Bonin forearc have Pd values of between 4.0 and 11.8 nmol/L, Pt values between 2.3 and 5.0 nmol/L and Au values between 126.9 and 1116.9 pmol/L. The precious metals are mobilized, and possibly adsorbed onto clay mineral surfaces, during diagenesis and burial of the volcanic-rich clays. Desorption during squeezing of the sediments may produce the enhanced precious metal concentrations in the analyzed fluids. The metals are mobilized in the fluids probably as neutral hydroxide, bisulfide, and ammonia complexes. Pt/Pd ratios are between 0.42 and 2.33, which is much lower than many of the potential sources for Pt and Pd but is consistent with the greater solubility of Pd compared with Pt in most natural low-temperature fluids

    Reconstructing thawing quintessence with multiple datasets

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    In this work we model the quintessence potential in a Taylor series expansion, up to second order, around the present-day value of the scalar field. The field is evolved in a thawing regime assuming zero initial velocity. We use the latest data from the Planck satellite, baryonic acoustic oscillations observations from the Sloan Digital Sky Survey, and Supernovae luminosity distance information from Union2.1 to constrain our models parameters, and also include perturbation growth data from the WiggleZ, BOSS and the 6dF surveys. The supernova data provide the strongest individual constraint on the potential parameters. We show that the growth data performance is competitive with the other datasets in constraining the dark energy parameters we introduce. We also conclude that the combined constraints we obtain for our model parameters, when compared to previous works of nearly a decade ago, have shown only modest improvement, even with new growth of structure data added to previously-existent types of data.Comment: 9 pages, 4 figures and 1 table. Version 2 with minor changes to match Physical Review D accepted versio

    Energy harvesting from transverse galloping

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    Some elastic bluff bodies under the action of a fluid flow can experience transverse galloping and lose stability if the flow velocity exceeds a critical value. For flow velocities higher than this critical value, there is an energy transfer from the flow to the body and the body develops an oscillatory motion. Usually, it is considered as an undesirable effect for civil or marine structures but here we will show that if the vibration is substantial, it can be used to extract useful energy from the surrounding flow. This paper explores analytically the potential use of transverse galloping in order to obtain energy. To this end, transverse galloping is described by a one-degree-of-freedom model where fluid forces obey the quasi-steady hypothesis. The influence of cross-section geometry and mechanical properties in the energy conversion factor is investigated
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