121 research outputs found

    Electrochemical investigation on localised corrosion under silica sand deposit layers of carbon steel within a bespoke test cell

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    The corrosion behaviour of deep pit-like features on carbon steel under silica sand deposits has been evaluated using a bespoke localised corrosion cell. Local pH and electrochemical measurements were performed, including impedance spectroscopy and galvanic coupling. The corrosion rate of X65 carbon steel at four different recession depths up to 9 mm was evaluated in the presence and absence of a ∼8 mm-thick silica dioxide deposit layer, in a carbon dioxide-saturated environment. The deposit reduced corrosion rates to approximately 1 mm·yr−1 and iron carbonate formed on the steel surface under the deposit due to an increase in local pH

    Structure-based design and synthesis of antiparasitic pyrrolopyrimidines targeting pteridine reductase 1

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    The treatment of Human African Trypanosomiasis remains a major unmet health need in sub-Saharan Africa. Approaches involving new molecular targets are important and pteridine reductase 1 (PTR1), an enzyme that reduces dihydrobiopterin in Trypanosoma spp. has been identified as a candidate target and it has been shown previously that substituted pyrrolo[2,3-d]pyrimidines are inhibitors of PTR1 from T. brucei (J. Med. Chem. 2010, 53, 221-229). In this study, 61 new pyrrolo[2,3-d]pyrimidines have been prepared, designed with input from new crystal structures of 23 of these compounds complexed with PTR1, and evaluated in screens for enzyme inhibitory activity against PTR1 and in vitro antitrypanosomal activity. 8 compounds were sufficiently active in both screens to take forward to in vivo evaluation. Thus although evidence for trypanocidal activity in a stage I disease model in mice was obtained, the compounds were too toxic to mice for further development

    Development of an automated underwater abrasion rig to determine galvanic effects during the growth and localised breakdown of surface films in CO₂-containing solutions

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    This paper outlines the development of an automated underwater abrasion rig to assist in understanding the galvanic interaction induced by surface films when continuous localised mechanical film breakdown is encountered on the surface of carbon steel in CO₂-containing environments. The rig enables the measurement of galvanic current between a small X65 steel pin and a larger steel specimen, as well as the intrinsic corrosion rate of an additional, uncoupled larger specimen. The surface film developed on the pin is removed periodically using an automated reciprocating and rotating shaft with a sand paper grit pad attached to the base, while the surface film is allowed to establish itself undisrupted on the large specimen. The setup essentially simulates a tribo-corrosion process where local removal of material occurs within a carbon steel pipeline as a result of periodic sand particle impingement. Initial results focus on validating the reproducibility of the technique, as well as determining the galvanic effects associated with iron carbide and iron carbonate for two model sets of conditions to highlight the capabilities of the system

    “I’m only a dog!” : the Rwandan genocide, dehumanisation and the graphic novel

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    Graphic novels written in response to the 1994 Rwandan genocide do not confine their depictions of traumatic violence to humans, but extend their coverage to show how the genocide impacted on animals and the environment. Through analysis of the presentation of people and their relationships with other species across a range of graphic narratives, this article shows how animal imagery was used to justify inhumane actions during the genocide, and argues that representations of animals remain central to the recuperation processes in a post-genocide context too. Whilst novels and films that respond to the genocide have been the focus of scholarly work (Dauge-Roth, 2010), the graphic novel has yet to receive substantial critical attention. This article therefore unlocks the archive of French-, Dutch- and English-language graphic narratives written in response to the genocide by providing the first in-depth, comparative analysis of their animal representations. It draws on recent methodological approaches derived from philosophy (Derrida, [2008] trans. 2009), postcolonial ecocriticism (Huggan and Tiffin, 2010) and postcolonial trauma theory (Craps, 2012) in order show how human-centred strategies for recovery, and associated symbolic orders that forcefully position the animal outside of human law, continue to engender unequal and potentially violent relationships between humans, and humans and other species. In this way, graphic narratives that gesture towards more equitable relationships between humans, animals and the environment can be seen to support the processes of recovery and reconciliation in post-genocide Rwanda

    Development of a novel once-through flow visualization technique for kinetic study of bulk and surface scaling

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    There is a considerable interest to investigate surface crystallization in order to have a full mechanistic understanding of how layers of sparingly soluble salts (scale) build on component surfaces. Despite much recent attention, a suitable methodology to improve on the understanding of the precipitation/deposition systems to enable the construction of an accurate surface deposition kinetic model is still needed. In this work, an experimental flow rig and associated methodology to study mineral scale deposition is developed. The once-through flow rig allows us to follow mineral scale precipitation and surface deposition in situ and in real time. The rig enables us to assess the effects of various parameters such as brine chemistry and scaling indices, temperature, flow rates, and scale inhibitor concentrations on scaling kinetics. Calcium carbonate (CaCO3) scaling at different values of the saturation ratio (SR) is evaluated using image analysis procedures that enable the assessment of surface coverage, nucleation, and growth of the particles with time. The result for turbidity values measured in the flow cell is zero for all the SR considered. The residence time from the mixing point to the sample is shorter than the induction time for bulk precipitation; therefore, there are no crystals in the bulk solution as the flow passes through the sample. The study shows that surface scaling is not always a result of pre-precipitated crystals in the bulk solution. The technique enables both precipitation and surface deposition of scale to be decoupled and for the surface deposition process to be studied in real time and assessed under constant condition

    Decolonizing Science and Science Education in a Postcolonial Space (Trinidad, a Developing Caribbean Nation, Illustrates)

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    The article addresses how remnant or transformed colonialist structures continue to shape science and science education, and how that impact might be mitigated within a postcolonial environment in favor of the development of the particular community being addressed. Though cognizant of, and resistant to, the ongoing colonial impact globally and nationally (and any attempts at subjugation, imperialism, and marginalization), this article is not about anticolonial science. Indeed, it is realized that the postcolonial state of science and science education is not simply defined, and may exist as a mix of the scientific practices of the colonizer and the colonized. The discussion occurs through a generic postcolonial lens and is organized into two main sections. First, the discussion of the postcolonial lens is eased through a consideration of globalization which is held here as the new colonialism. The article then uses this lens to interrogate conceptions of science and science education, and to suggest that the mainstream, standard account of what science is seems to represent a globalized- or arguably a Western, modern, secular-conception of science. This standard account of science can act as a gatekeeper to the indigenous ways of being, knowing, and doing of postcolonial populations. The article goes on to suggest that as a postcolonial response, decolonizing science and science education might be possible through practices that are primarily contextually respectful and responsive. That is, localization is suggested as one possible antidote to the deleterious effects of globalization. Trinidad, a postcolonial developing Caribbean nation, is used as illustration

    Prophylactic and therapeutic treatment with a synthetic analogue of a parasitic worm product prevents experimental arthritis and inhibits IL-1β production via NRF2-mediated counter-regulation of the inflammasome

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    Rheumatoid arthritis (RA) remains a debilitating autoimmune condition as many patients are refractory to existing conventional and biologic therapies, and hence successful development of novel treatments remains a critical requirement. Towards this, we now describe a synthetic drug-like small molecule analogue, SMA-12b, of an immunomodulatory parasitic worm product, ES-62, which acts both prophylactically and therapeutically against collagen-induced arthritis (CIA) in mice. Mechanistic analysis revealed that SMA-12b modifies the expression of a number of inflammatory response genes, particularly those associated with the inflammasome in mouse bone marrow-derived macrophages and indeed IL-1β was the most down-regulated gene. Consistent with this, IL-1β was significantly reduced in the joints of mice with CIA treated with SMA-12b. SMA-12b also increased the expression of a number of genes associated with anti-oxidant responses that are controlled by the transcription factor NRF2 and critically, was unable to inhibit expression of IL-1β by macrophages derived from the bone marrow of NRF2−/− mice. Collectively, these data suggest that SMA-12b could provide the basis of an entirely novel approach to fulfilling the urgent need for new treatments for RA

    Staphylococcus aureus bacteriuria as a prognosticator for outcome of Staphylococcus aureus bacteremia: a case-control study

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    <p>Abstract</p> <p>Background</p> <p>When <it>Staphylococcus aureus </it>is isolated in urine, it is thought to usually represent hematogenous spread. Because such spread might have special clinical significance, we evaluated predictors and outcomes of <it>S. aureus </it>bacteriuria among patients with <it>S. aureus </it>bacteremia.</p> <p>Methods</p> <p>A case-control study was performed at John H. Stroger Jr. Hospital of Cook County among adult inpatients during January 2002-December 2006. Cases and controls had positive and negative urine cultures, respectively, for <it>S. aureus</it>, within 72 hours of positive blood culture for <it>S. aureus</it>. Controls were sampled randomly in a 1:4 ratio. Univariate and multivariable logistic regression analyses were done.</p> <p>Results</p> <p>Overall, 59% of patients were African-American, 12% died, 56% of infections had community-onset infections, and 58% were infected with methicillin-susceptible <it>S. aureus </it>(MSSA). Among 61 cases and 247 controls, predictors of <it>S. aureus </it>bacteriuria on multivariate analysis were urological surgery (OR = 3.4, p = 0.06) and genitourinary infection (OR = 9.2, p = 0.002). Among patients who died, there were significantly more patients with bacteriuria than among patients who survived (39% vs. 17%; p = 0.002). In multiple Cox regression analysis, death risks in bacteremic patients were bacteriuria (hazard ratio 2.9, CI 1.4-5.9, p = 0.004), bladder catheter use (2.0, 1.0-4.0, p = 0.06), and Charlson score (1.1, 1.1-1.3, p = 0.02). Neither length of stay nor methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) infection was a predictor of <it>S. aureus </it>bacteriuria or death.</p> <p>Conclusions</p> <p>Among patients with <it>S. aureus </it>bacteremia, those with <it>S. aureus </it>bacteriuria had 3-fold higher mortality than those without bacteriuria, even after adjustment for comorbidities. Bacteriuria may identify patients with more severe bacteremia, who are at risk of worse outcomes.</p

    Lost trophies: Hunting animals and the imperial souvenir in Walton Ford’s Pancha Tantra

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    This article argues that the work of contemporary American artist Walton Ford stages the paradoxical role that trophy hunting played in both establishing and undermining the strict racial, biological and ecological hierarchization of colonial environments. American Flamingo (1992) and Lost Trophy (2005), from the 2009 collection Pancha Tantra, foreground how the tradition of nineteenth-century naturalist art, characterized by John James Audubon, and popular narratives of trophy hunting expeditions, such as Ernest Hemingway’s Green Hills of Africa (1935), are complicit in colonialist domination. In doing so, Ford’s watercolours of hunted animals, which adopt many of the tropes popularized by Audubon, point to the Spivakian notion of “epistemic violence” behind an ostensibly innocuous, taxonomic art form. At the same time, the painting Lost Trophy recalls the writings of Joseph Conrad and George Orwell, investing animals with the power to unsettle the assumed superiority of the colonial hunter. My interdisciplinary analysis adopts literary strategies for reading artistic works, allowing for a broader understanding of the growing relationship between postcolonial studies and ecocriticism

    A bubble in the vein: suicide, community, and the rejection of neoliberalism in Hanya Yanagihara's A little life and Miriam Toews's All my puny sorrows

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    This chapter explores how Marlon James’ A Brief History of Seven Killings (2014) and Paulo Lins’ Cidade de Deus (City of God 1997) speak to the contemporary crisis in the neoliberal regime of accumulation, as well as to the initial struggle to impose neoliberalism in the global South. A Brief History registers the fallout from the turmoil in Jamaica in the 1970s, when Michael Manley’s efforts to pursue a path of democratic socialism were undermined by party-political gang warfare, economic crisis, and the impact of US imperialism. City of God, meanwhile, focuses primarily on the closed world of the titular favela, located on the western edge of Rio de Janeiro. Despite this limited compass, the “inexorable weight of contemporary history makes itself felt” in the novel’s representation of the desperate lives of its protagonists (Schwarz, Two Girls: And Other Essays. London: Verso, 2012: 227). Spanning the period from the 1960s to the early 1980s, the narrative is shadowed by the presence of the dictatorship in Brazil and by the unfolding logic of the world-economy. Through their formal logics and stylistic mannerisms, City of God and A Brief History rehearse the possibilities for both reactionary and progressive class realignments in the wake of hegemonic dissolution. The precise nature of these possibilities, however, is differentiated in the two novels by the specific social contexts and historical moments to which they respond
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