265 research outputs found

    Adsorption geometry and electronic structure of iron phthalocyanine on Ag surfaces: A LEED and photoelectron momentum mapping study

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    We present a comprehensive study of the adsorption behavior of iron phthalocyanine on the low-index crystal faces of silver. By combining measurements of the reciprocal space by means of photoelectron momentum mapping and low energy electron diffraction, the real space adsorption geometries are reconstructed. At monolayer coverage ordered superstructures exist on all studied surfaces containing one molecule in the unit cell in case of Ag(100) and Ag(111), and two molecules per unit cell for Ag(110). The azimuthal tilt angle of the molecules against the high symmetry directions of the substrate is derived from the photoelectron momentum maps. A comparative analysis of the momentum patterns on the substrates with different symmetry indicates that both constituents of the twofold degenerate FePc lowest unoccupied molecular orbital are occupied by charge transfer from the substrate at the interface

    Adsorption of cytosine and aza derivatives of cytidine on Au single crystal surfaces

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    The adsorption of cytosine on the Au(111) and Au(110) surfaces has been studied using both aqueous deposition and evaporation in vacuum to prepare the samples. Soft X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure spectroscopy (NEXAFS) were used to determine the electronic structure and orientation of the adsorbates. In addition, three derivatives of cytosine, 6-azacytosine, 6-azacytidine and 5- azacytidine, were studied. Monolayer films of the latter three samples were adsorbed on Au(111) from aqueous solution, and the nature of bonding was determined. Spectra have been interpreted in the light of published calculations of free cytosine molecules and new ab initio calculations of the other compounds. Surface core level shifts of Au 4f imply that all of these compounds are chemisorbed. Cytosine adsorbs as a single tautomer, but in two chemical states with different surface-molecule bonding. For deposition in vacuum, a flat-lying molecular state bonded through the N(3) atom of the pyrimidine ring dominates, but a second state is also present. For deposition from solution, the second state dominates, with the molecular plane no longer parallel to the surface. This state also bonds through the N(3) atom, but in addition interacts with the surface via the amino group. Two tautomers of 6-azacytosine were observed, and they and 6-azacytidine adsorb with similar geometries, chemically bonding via the azacytosine ring. The ribose ring does not appear to perturb the adsorption of azacytidine compared with azacytosine. The azacytosine ring is nearly but not perfectly parallel to the surface, like 5-azacytidine, which adsorbs as an imino tautomer. ...Comment: 40 pages, 3 tables and 8 figure

    Law, politics and the governance of English and Scottish joint-stock companies 1600-1850

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    This article examines the impact of law on corporate governance by means of a case study of joint-stock enterprise in England and Scotland before 1850. Based on a dataset of over 450 company constitutions together with qualitative information on governance practice, it finds little evidence to support the hypothesis that common-law regimes such as England were more supportive of economic growth than civil-law jurisdictions such as Scotland: indeed, levels of shareholder protection were slightly stronger in the civil-law zone. Other factors, such as local political institutions, played a bigger role in shaping organisational forms and business practice

    The left superior temporal gyrus is a shared substrate for auditory short-term memory and speech comprehension: evidence from 210 patients with stroke

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    Competing theories of short-term memory function make specific predictions about the functional anatomy of auditory short-term memory and its role in language comprehension. We analysed high-resolution structural magnetic resonance images from 210 stroke patients and employed a novel voxel based analysis to test the relationship between auditory short-term memory and speech comprehension. Using digit span as an index of auditory short-term memory capacity we found that the structural integrity of a posterior region of the superior temporal gyrus and sulcus predicted auditory short-term memory capacity, even when performance on a range of other measures was factored out. We show that the integrity of this region also predicts the ability to comprehend spoken sentences. Our results therefore support cognitive models that posit a shared substrate between auditory short-term memory capacity and speech comprehension ability. The method applied here will be particularly useful for modelling structure–function relationships within other complex cognitive domains

    UV-stable paper coated with APTES-modified P25 TiO2 nanoparticles

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    In order to inhibit the photocatalytic degradation of organic material supports induced by small titania (TiO2) nanoparticles, highly photocatalytically active, commercially available P25-TiO2 nanoparticles were first modified with a thin layer of (3-aminopropyl) triethoxysilane (APTES), which were then deposited and fixed onto the surface of paper samples via a simple, dip-coating process in water at room temperature. The resultant APTES-modified P25 TiO2 nanoparticle-coated paper samples exhibit much greater stability to UV-illumination than uncoated blank reference paper. Very little, or no, photo-degradation in terms of brightness and whiteness, respectively, of the P25-TiO2-nanoparticle-treated paper is observed. There are many other potential applications for this Green Chemistry approach to protect cellulosic fibres from UV-bleaching in sunlight and to protect their whiteness and maintain their brightness

    INSPIRE: A phase III study of the BLP25 liposome vaccine (L-BLP25) in Asian patients with unresectable stage III non-small cell lung cancer

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    <p>Abstract</p> <p>Background</p> <p>Previous research suggests the therapeutic cancer vaccine L-BLP25 potentially provides a survival benefit in patients with locally advanced unresectable stage III non-small cell lung carcinoma (NSCLC). These promising findings prompted the phase III study, INSPIRE, in patients of East-Asian ethnicity. East-Asian ethnicity is an independent favourable prognostic factor for survival in NSCLC. The favourable prognosis is most likely due to a higher incidence of EGFR mutations among this patient population.</p> <p>Methods/design</p> <p>The primary objective of the INSPIRE study is to assess the treatment effect of L-BLP25 plus best supportive care (BSC), as compared to placebo plus BSC, on overall survival time in East-Asian patients with unresectable stage III NSCLC and either documented stable disease or an objective response according to the Response Evaluation Criteria in Solid Tumors (RECIST) criteria following primary chemoradiotherapy. Those in the L-BLP25 arm will receive a single intravenous infusion of cyclophosphamide (300 mg/m<sup>2</sup>) 3 days before the first L-BLP25 vaccination, with a corresponding intravenous infusion of saline to be given in the control arm. A primary treatment phase of 8 subcutaneous vaccinations of L-BLP25 930 μg or placebo at weekly intervals will be followed by a maintenance treatment phase of 6-weekly vaccinations continued until disease progression or discontinuation from the study.</p> <p>Discussion</p> <p>The ongoing INSPIRE study is the first large study of a therapeutic cancer vaccine specifically in an East-Asian population. It evaluates the potential of maintenance therapy with L-BLP25 to prolong survival in East-Asian patients with stage III NSCLC where there are limited treatment options currently available.</p> <p>Study number</p> <p>EMR 63325-012</p> <p>Trial Registration</p> <p>Clinicaltrials.gov reference: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01015443">NCT01015443</a></p
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