2,873 research outputs found

    Electronic and Structural Study of the Reactivity of Cu+ with CO, H2O, O2, N2 and their Mixture

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    A detailed theoretical study of the gas phase reactivity of copper cation (Cu+) with CO, H2O, O2, N2 and their mixture was performed and compared to experimental results to determine the ability of Cu+ to act as a low-temperature catalyst for CO oxidation. It was found that Cu+ binds strongest to CO, followed by H2O, N2, and O2, strongly interacting with each species until reaching saturation at a maximum of four ligands. It was also found that a single Cu+ cannot by itself activate the O2 molecule as small copper cluster anions can, leading to CO2formation Nevertheless, since moisture and impurities on the surface of a catalyst can modify its chemical activity, it is important to understand at the atomic level the interaction between the active site (Cu+) and the binding molecules in order to help to identify intermediates and key reaction steps that control the reactivity and catalytic activity

    'Respect me: respect self' - the key to improved global relationships.

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    This paper examines the definitions of respect in a 21st century globally inclusive environment, with a view to exploring the implications for nurturing harmonious working relationships in, and between culturally diverse economically active groups. It is based on research conducted since 2005 which explores the meanings attached to, and experience of, respect from the perspective of undergraduate students in a UK university business school, who worked together on a consulting to business module. The research methodology consisted of tracking via focus group interactions and video records of two culturally diverse groups, comprising seven students each, over a two year period, with approximately eight focus group – video sessions per group. Significantly, our findings suggest that respect is an important shared value, and one that all students acknowledge as having an impact on their behaviour, attitudes and emotions. We argue that in our case, respect develops as an awareness of difference and is based on systematically produced data of the actors’ life experience, rather than, fictions or stereotypes. We suggest that this process encourages a positive approach to respect as it facilitates a shift in behaviours, attitudes, and ‘mental models’, (the latter, as described by Senge et al 1994). The significance of respect to the development and maintenance of both an economic democracy and for transnational relations between such democracies, is therefore crucial if there is to be equal access for all, regardless of their diversity, to the benefits which should accrue to all those who participate in the wealth creation activity of their society and the global economy

    Integrated water resource planning in the city of Cape Town

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    Over the last decade the approach to dealing with an increasing water demand in the Cape Metropolitan Area (CMA) has progressively shifted from a supply oriented philosophy to one where strategies for reducing the demand are integrated with supply management. While there is still much to be done to implement a totally integrated approach, a firm foundation has been laid. Water demand management as an approach became increasingly prominent in the CCT supply area in the mid 1990s. Accordingly, a Water Demand Management Section was formed in the Water Department of the former Cape Metropolitan Council (CMC). This section was instrumental in shifting the approaches to water demand management in the 6 local councils in the CMA. Towards the end of 1999 it became increasingly clear that there was a need to adopt an integrated water resource planning approach to manage the future water demand. As a result, the former CMC appointed consultants to carry out an “Integrated Water Resource Planning” (IWRP) study. The results of the IWRP study indicate that a significant saving in water demand could be achieved through the implementation of water demand management initiatives. In comparison to the water supply options, the water demand management initiatives would have a significantly lower implementation cost, could be implemented in a shorter time frame and were generally more environmentally and socially acceptable. Recommendations were made to the new City of Cape Town (CCT) – formed in December 2000 through the amalgamation of the former CMC and the 6 local councils - on where to focus their resources and attention with the aim of meeting and managing the water demand. The water demand in the CCT has decreased significantly since November 2000. This can be attributed to the recent water restrictions as well as the implementation of water demand management initiatives. The reduction in water demand has delayed the need for the implementation of additional water augmentation schemes other than the Berg Water Project.. Water SA Vol. 30 (5) 2005: pp.100-10

    Similarities and differences between the E5 oncoproteins of bovine papillomaviruses type 1 and type 4: Cytoskeleton, motility and invasiveness in E5-transformed bovine and mouse cells

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    Bovine papillomaviruses (BPVs) are oncogenic viruses. In cattle, BPV-1/2 is associated with urinary bladder cancer and BPV-4 with upper GI tract cancer. BPV E5 is a small hydrophobic protein localised in the endoplasmic reticulum (ER) and Golgi apparatus (GA). E5 is the major transforming protein of BPVs, capable of inducing cell transformation in cultured mouse fibroblasts and, in cooperation with E7, in primary bovine cells. E5-induced cell transformation is accompanied by activation of several cellular protein kinases, including growth factor receptors, and alkalinisation of endosomes and GA. We have reported that BPV E5 causes swelling and fragmentation of the GA and extensive vacuolisation of the cytoplasm. We now show that E5 from both BPV-1 and BPV-4 disturbs the actin cytoskeleton and focal adhesions in transformed bovine cells, where these morphological and behavioural characteristics are accompanied by hyperphosphorylation of the cellular phosphotyrosine kinase c-src. Both BPV-1 and BPV-4 E5 increase the motility of transformed mouse cells, but only BPV-1 E5 causes transformed mouse cells to penetrate a matrigel matrix. BPV-1 transformed mouse cells, but not BPV-4 transformed mouse cells, have hyperhpsphorylated c-src

    Mechanisms of growth inhibition of primary prostate epithelial cells following gamma irradiation or photodynamic therapy including senscence, necrosis, and autophagy, but not apoptosis

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    In comparison to more differentiated cells, prostate cancer stem-like cells are radioresistant, which could explain radio-recurrent prostate cancer. Improvement of radiotherapeutic efficacy may therefore require combination therapy. We have investigated the consequences of treating primary prostate epithelial cells with gamma irradiation and photodynamic therapy (PDT), both of which act through production of reactive oxygen species (ROS). Primary prostate epithelial cells were cultured from patient samples of benign prostatic hyperplasia and prostate cancer prior to treatment with PDT or gamma irradiation. Cell viability was measured using MTT and alamar blue assay, and cell recovery by colony-forming assays. Immunofluorescence of gamma-H2AX foci was used to quantify DNA damage, and autophagy and apoptosis were assessed using Western blots. Necrosis and senescence were measured by propidium iodide staining and beta-galactosidase staining, respectively. Both PDT and gamma irradiation reduced the colony-forming ability of primary prostate epithelial cells. PDT reduced the viability of all types of cells in the cultures, including stem-like cells and more differentiated cells. PDT induced necrosis and autophagy, whereas gamma irradiation induced senescence, but neither treatment induced apoptosis. PDT and gamma irradiation therefore inhibit cell growth by different mechanisms. We suggest these treatments would be suitable for use in combination as sequential treatments against prostate cancer

    Low Temperature Plasma : A Novel Focal Therapy for Localized Prostate Cancer?

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    Despite considerable advances in recent years for the focal treatment of localized prostate cancer, high recurrence rates and detrimental side effects are still a cause for concern. In this review, we compare current focal therapies to a potentially novel approach for the treatment of early onset prostate cancer: low temperature plasma. The rapidly evolving plasma technology has the potential to deliver a wide range of promising medical applications via the delivery of plasma-induced reactive oxygen and nitrogen species. Studies assessing the effect of low temperature plasma on cell lines and xenografts have demonstrated DNA damage leading to apoptosis and reduction in cell viability. However, there have been no studies on prostate cancer, which is an obvious candidate for this novel therapy. We present here the potential of low temperature plasma as a focal therapy for prostate cancer

    Responses to Nitrogen Fertilizer in Dairy Pastures with Differing Phosphorus Fertility in South Eastern Australia

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    The application of nitrogen (N) fertilizer to temperate pastures is an increasingly popular management tool for boosting pasture production on dairy farms in Australia. However, limited information is available about N fertilizer responses that can be obtained from pastures with varying levels of phosphorus (P) fertility. A field experiment examining the initial and residual response of pasture growth to urea was carried out within a large dairy farmlet study, in October 1998. The four P fertility treatments (Olsen P values) ranged from 9 to 32 mg/kg. Dry matter yields increased with increasing N rates in all treatments, at both harvests. Only pastures with Olsen P values of \u3c 12 mg/kg had a significantly lower response to N fertilizer
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