931 research outputs found

    Thin films of a dimeric ruthenium phthalocyanine complex on gold

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    Thin films of a new dimeric ruthenium phthalocyanine complex bearing a thioester-functionalized axial ligand were formed on gold surfaces. Characterization of the thin films by laser ablation-inductively coupled-mass spectrometry and scanning tunneling microscopy revealed that the films do not have any long-range order. Β© 2009 Elsevier B.V. All rights reserved

    Thin films of Ruthenium Phthalocyanine complexes

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    Four new ruthenium phthalocyanine complexes bearing axial ligands with thioacetate groups that facilitate thin film formation on gold surfaces are presented. Scanning tunnelling microscopy (STM) images and surface coverage data obtained by solution inductively coupled plasma mass spectrometry (ICP-MS) experiments show that peripheral and axial ligand substituents on the complexes have a significant effect on their surface coverage. A laser ablation ICP-MS technique that provides information about thin films across macro-sized areas is described here for the first time. Using the technique, the maximum surface coverage of a ruthenium phthalocyanine complex was found to occur within one minute of gold substrate immersion in the complexcontaining solution

    The impact of ocean acidification on the functional morphology of foraminifera

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    This work was supported by the NERC UK Ocean Acidification Research Programme grant NE/H017445/1. WENA acknowledges NERC support (NE/G018502/1). DMP received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism’s survival and fitness.Publisher PDFPeer reviewe

    Software Sustainability: The Modern Tower of Babel

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    The development of sustainable software has been identified as one of the key challenges in the field of computational science and engineering. However, there is currently no agreed definition of the concept. Current definitions range from a composite, non-functional requirement to simply an emergent property. This lack of clarity leads to confusion, and potentially to ineffective and inefficient efforts to develop sustainable software systems. The aim of this paper is to explore the emerging definitions of software sustainability from the field of software engineering in order to contribute to the question, what is software sustainability? The preliminary analysis suggests that the concept of software sustainability is complex and multifaceted with any consensus towards a shared definition within the field of software engineering yet to be achieved

    Enhanced etoposide sensitivity following adenovirus-mediated human topoisomerase II Ξ± gene transfer is independent of topoisomerase II Ξ²

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    The roles that the Ξ± and Ξ² isoforms of topoisomerase II (topo II) play in anticancer drug action were determined using MDA-VP etoposide-resistant human breast cancer cells and a newly constructed adenoviral vector containing the topo IIΞ± gene (Ad-topo IIΞ±). MDA-VP cells were more resistant to etoposide than to amsacrine and had more resistance to etoposide than did MDA-parental cells. MDA-VP cells also expressed lower topo IIΞ± RNA and protein levels than parental cells but had comparable topo IIΞ² levels. After infection with Ad-topo IIΞ±, topo IIΞ±, RNA and protein levels increased significantly, as did the cells' sensitivity to etoposide. In contrast, topo IIΞ² levels remained constant with little alteration in the cells' sensitivity to amsacrine. Band-depletion immunoblotting assays indicated that topo IIΞ± was depleted in etoposide-treated, Ad-topo IIΞ±-transduced MDA-VP cells but not in amsacrine-treated cells. Topo IIΞ² was depleted in amsacrine-treated, Ad-topo IIΞ±-MDA-VP cells, with little change in the topo IIΞ± levels. These results suggest that topo IIΞ± gene transfer does not alter topo IIΞ² expression and that enhanced sensitivity to etoposide is therefore secondary to change in topo IIΞ± levels. These studies support the theory that etoposide preferentially targets topo IIΞ±, while amsacrine targets topo IIΞ². Β© 2001 Cancer Research Campaign http://www.bjcancer.co

    Risk factors for antenatal depression, postnatal depression and parenting stress

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    <p>Abstract</p> <p>Background</p> <p>Given that the prevalence of antenatal and postnatal depression is high, with estimates around 13%, and the consequences serious, efforts have been made to identify risk factors to assist in prevention, identification and treatment. Most risk factors associated with postnatal depression have been well researched, whereas predictors of antenatal depression have been less researched. Risk factors associated with early parenting stress have not been widely researched, despite the strong link with depression. The aim of this study was to further elucidate which of some previously identified risk factors are most predictive of three outcome measures: antenatal depression, postnatal depression and parenting stress and to examine the relationship between them.</p> <p>Methods</p> <p>Primipara and multiparae women were recruited antenatally from two major hoitals as part of the <it>beyondblue </it>National Postnatal Depression Program <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. In this subsidiary study, 367 women completed an additional large battery of validated questionnaires to identify risk factors in the antenatal period at 26–32 weeks gestation. A subsample of these women (N = 161) also completed questionnaires at 10–12 weeks postnatally. Depression level was measured by the Beck Depression Inventory (BDI).</p> <p>Results</p> <p>Regression analyses identified significant risk factors for the three outcome measures. (1). Significant predictors for antenatal depression: low self-esteem, antenatal anxiety, low social support, negative cognitive style, major life events, low income and history of abuse. (2). Significant predictors for postnatal depression: antenatal depression and a history of depression while also controlling for concurrent parenting stress, which was a significant variable. Antenatal depression was identified as a mediator between seven of the risk factors and postnatal depression. (3). Postnatal depression was the only significant predictor for parenting stress and also acted as a mediator for other risk factors.</p> <p>Conclusion</p> <p>Risk factor profiles for antenatal depression, postnatal depression and parenting stress differ but are interrelated. Antenatal depression was the strongest predictor of postnatal depression, and in turn postnatal depression was the strongest predictor for parenting stress. These results provide clinical direction suggesting that early identification and treatment of perinatal depression is important.</p
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