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61.
B. J. Eastwood P. A. Christensen R. D. Armstrong N. R. Bates 《Journal of Solid State Electrochemistry》1999,3(4):179-186
The suitability of a polymeric composite material for use as part of an anode structure in a cathodic protection system has
been examined. The composite material was a conductive blend (volume resistivity typically 1.5 Ω cm) of carbon black in a
polyethylene binder. A long operational lifetime for the material demands that the rate of carbon loss must be low. In the
work reported here, electrochemical and in situ analytical techniques were employed to characterise the performance of the material over a wide range of anodic current densities
in a variety of aqueous electrolytes. The predominant anodic electrochemical reaction on the polymeric material is CO2 formation in acid and neutral solutions, which causes loss of carbon from the surface and the development of a non-conducting
layer of polyethylene. The characteristics of the reaction suggest that it occurs via the discharge of H2O. In alkaline pH, however, the anodic reactions are more complex. A high OH− concentration (pH 12 or higher) favours the formation of oxygen rather than CO2, particularly at low anodic potentials. The presence of CO3
2− in the electrolyte catalyses the evolution of oxygen at pH values as low as 9. The electrochemical formation of oxygen always
occurs in parallel with the generation of some humic acid in the solution.
Received: 23 July 1998 / Accepted: 17 November 1998 相似文献
62.
63.
Lamprecht DA Muneri NO Eastwood H Naidoo KJ Strauss E Jardine A 《Organic & biomolecular chemistry》2012,10(27):5278-5288
MshB is the N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-D-glucopyranoside (GlcNAc-Ins) deacetylase active as one of the enzymes involved in the biosynthesis of mycothiol (MSH), a protective low molecular weight thiol present only in Mycobacterium tuberculosis and other actinomycetes. In this study, structural analogues of GlcNAc-Ins in which the inosityl moiety is replaced by a chromophore were synthesized and evaluated as alternate substrates of MshB, with the goal of identifying a compound that would be useful in high-throughput assays of the enzyme. In an unexpected and surprising finding one of the GlcNAc-Ins analogues is shown to undergo a Smiles rearrangement upon MshB-mediated deacetylation, uncovering a free thiol group. We demonstrate that this chemistry can be exploited for the development of the first continuous assay of MshB activity based on the detection of thiol formation by DTNB (Ellman's reagent); such an assay should be ideally suited for the identification of MshB inhibitors by means of high-throughput screens in microplates. 相似文献
64.
The propagation of reconnection signatures and their associated energy are examined using kinetic particle-in-cell simulations and Cluster satellite observations. It is found that the quadrupolar out-of-plane magnetic field near the separatrices is associated with a kinetic Alfvén wave. For magnetotail parameters, the parallel propagation of this wave is super-Alfvénic (V(∥) ~ 1500-5500 km/s) and generates substantial Poynting flux (S ~ 10(-5)-10(-4) W/m(2)) consistent with Cluster observations of magnetic reconnection. This Poynting flux substantially exceeds that due to frozen-in ion bulk outflows and is sufficient to generate white light aurora in Earth's ionosphere. 相似文献
65.
Shan Y Kim ET Eastwood MP Dror RO Seeliger MA Shaw DE 《Journal of the American Chemical Society》2011,133(24):9181-9183
Although the thermodynamic principles that control the binding of drug molecules to their protein targets are well understood, detailed experimental characterization of the process by which such binding occurs has proven challenging. We conducted relatively long, unguided molecular dynamics simulations in which a ligand (the cancer drug dasatinib or the kinase inhibitor PP1) was initially placed at a random location within a box that also contained a protein (Src kinase) to which that ligand was known to bind. In several of these simulations, the ligand correctly identified its target binding site, forming a complex virtually identical to the crystallographically determined bound structure. The simulated trajectories provide a continuous, atomic-level view of the entire binding process, revealing persistent and noteworthy intermediate conformations and shedding light on the role of water molecules. The technique we employed, which does not assume any prior knowledge of the binding site's location, may prove particularly useful in the development of allosteric inhibitors that target previously undiscovered binding sites. 相似文献
66.
67.
A smooth 1-form on real projective space with vanishing integral along all geodesics is said to have zero energy. Such a 1-form is necessarily the exterior derivative of a smooth function. We formulate a general version of this theorem for tensor fields on real projective space and prove it using methods of complex analysis. A key ingredient is the cohomology of involutive structures. 相似文献
68.
We present several examples of homogeneous domains in complex space that do not have bounded realisations. The domains are equivalent to tubes over affinely homogeneous domains in real space. 相似文献
69.
70.