66 research outputs found

    The Erotic and the Vulgar: Visual Culture and Organized Labor's Critique of U.S. Hegemony in Occupied Japan

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    This essay engages the colonial legacy of postwar Japan by arguing that the political cartoons produced as part of the postwar Japanese labor movement’s critique of U.S. cultural hegemony illustrate how gendered discourses underpinned, and sometimes undermined, the ideologies formally represented by visual artists and the organizations that funded them. A significant component of organized labor’s propaganda rested on a corpus of visual media that depicted women as icons of Japanese national culture. Japan’s most militant labor unions were propagating anti-imperialist discourses that invoked an engendered/endangered nation that accentuated the importance of union roles for men by subordinating, then eliminating, union roles for women

    The association of academic tracking to depressive symptoms among adolescents in three Caribbean countries

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    <p>Abstract</p> <p>Background</p> <p>Students who are tracked into low performing schools or classrooms that limit their life chances may report increased depressive symptoms. Limited research has been conducted on academic tracking and its association with depressive symptoms among high school students in the Caribbean. This project examines levels of depressive symptoms among tenth grade students tracked within and between high schools in Jamaica, St. Vincent and St. Kitts and Nevis.</p> <p>Methods</p> <p>Students enrolled in grade ten of the 2006/2007 academic year in Jamaica, St. Kitts and Nevis and St. Vincent were administered the Beck Depression Inventory II (BDI-II). In Jamaica and St. Vincent, academic tracking was operationalized using data provided by the local Ministries of Education. These Ministries ranked ordered schools according to students' performance on Caribbean school leaving examinations. In St. Kitts and Nevis tracking was operationalized by classroom assignments within schools whereby students were grouped into classrooms according to their levels of academic achievement. Multiple regression analyses were conducted to examine the relationships between academic tracking and BDI-II depression scores.</p> <p>Results</p> <p>A wide cross-section of 4<sup>th </sup>form students in each nation was sampled (n = 1738; 278 from Jamaica, 737 St. Kitts and Nevis, 716 from St. Vincent; 52% females, 46.2% males and 1.8% no gender reported; age 12 to 19 years, mean = 15.4 yrs, sd = .9 yr). Roughly half (53%) of the students reported some symptoms of depression with 19.2% reporting moderate and 10.7% reporting severe symptoms of depression. Students in Jamaica reported significantly higher depression scores than those in either St. Kitts and Nevis or St. Vincent (p < .01). Students assigned to a higher academic track reported significantly lower BDI-II scores than students who were assigned to the lower academic track (p < .01).</p> <p>Conclusions</p> <p>There appears to be an association between academic tracking and depressive symptoms that is differentially manifested across the islands of Jamaica, St. Kitts and Nevis and St. Vincent.</p

    Microglial activation and chronic neurodegeneration

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    Microglia, the resident innate immune cells in the brain, have long been implicated in the pathology of neurode-generative diseases. Accumulating evidence points to activated microglia as a chronic source of multiple neurotoxic factors, including tumor necrosis factor-α, nitric oxide, interleukin-1β, and reactive oxygen species (ROS), driving progressive neuron damage. Microglia can become chronically activated by either a single stimulus (e.g., lipopolysaccharide or neuron damage) or multiple stimuli exposures to result in cumulative neuronal loss with time. Although the mechanisms driving these phenomena are just beginning to be understood, reactive microgliosis (the microglial response to neuron damage) and ROS have been implicated as key mechanisms of chronic and neurotoxic microglial activation, particularly in the case of Parkinson’s disease. We review the mechanisms of neurotoxicity associated with chronic microglial activation and discuss the role of neuronal death and microglial ROS driving the chronic and toxic microglial phenotype

    Clinical outcomes and response to treatment of patients receiving topical treatments for pyoderma gangrenosum: a prospective cohort study

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    Background: pyoderma gangrenosum (PG) is an uncommon dermatosis with a limited evidence base for treatment. Objective: to estimate the effectiveness of topical therapies in the treatment of PG. Methods: prospective cohort study of UK secondary care patients with a clinical diagnosis of PG suitable for topical treatment (recruited July 2009 to June 2012). Participants received topical therapy following normal clinical practice (mainly Class I-III topical corticosteroids, tacrolimus 0.03% or 0.1%). Primary outcome: speed of healing at 6 weeks. Secondary outcomes: proportion healed by 6 months; time to healing; global assessment; inflammation; pain; quality-of-life; treatment failure and recurrence. Results: Sixty-six patients (22 to 85 years) were enrolled. Clobetasol propionate 0.05% was the most commonly prescribed therapy. Overall, 28/66 (43.8%) of ulcers healed by 6 months. Median time-to-healing was 145 days (95% CI: 96 days, ∞). Initial ulcer size was a significant predictor of time-to-healing (hazard ratio 0.94 (0.88;80 1.00); p = 0.043). Four patients (15%) had a recurrence. Limitations: No randomised comparator Conclusion: Topical therapy is potentially an effective first-line treatment for PG that avoids possible side effects associated with systemic therapy. It remains unclear whether more severe disease will respond adequately to topical therapy alone

    Smectite suspension structural behaviour

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    Smectite suspensions, at low solids contents, are known to be naturally high in volume with diverse structural properties. The changing structural properties of smectite aqueous suspensions in the absence and presence of calcium ions were investigated using an acoustosizer and an advanced cryo-SEM technique to further understand and thereby control their environmental impact. In the absence of Ca(II) ions, smectite particles are present as a colloidally stable sol due to electrical double layer repulsion of the negatively charged platelets. The smectite network is observed to be extended throughout the suspension via clay platelets networking with an edge–edge (EE) orientation due to high basal surface repulsion. After the initial addition of Ca(II) ions, the smectite negative zeta potential reduces and the smectite platelets coagulate forming 2 µm aggregates. The platelets are randomly orientated, lettuce-like, coagulated aggregates with a high presence of both edge–edge (EE) and edge–face (EF) orientations. After equilibration, the smectite platelets forming an orientated honeycomb cellular structure comprised of face–face (FF) multiply sheet aggregates. The voids in the cellular structure are larger than prior to Ca(II) addition, measured at 2–8 µm. The changing structural properties of a smectite suspension in the absence and presence of Ca(II) greatly influence smectite stability and in turn, mineral processing and/or environmental management. Adequate time is required to allow suppression of the initial swelling of the smectite, full Ca(II) exchange and platelet aggregation

    Kaolinite flocculation structure

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    Effective flocculation and dewatering of mineral processing streams containing colloidal clays has become increasingly urgent. Release of water from slurries in tailings streams and dam beds for recycle water consumption, is usually slow and incomplete. To achieve fast settling and minimization of retained water, individual particles need to be bound, in the initial stages of thickening, into large, high-density aggregates, which may sediment more rapidly with lower intra-aggregate water content. Quantitative cryo-SEM image analysis shows that the structure of aggregates formed before flocculant addition has a determinative effect on these outcomes. Without flocculant addition, 3 stages occur in the mechanism of primary dewatering of kaolinite at pH 8: initially, the dispersed structures already show edge–edge (EE) and edge–face (EF) inter-particle associations but these are open, loose and easily disrupted; in the hindered settling region, aggregates are in adherent, chain-like structures of EE and stairstep face–face (FF) associations; this network structure slowly partially rearranges from EE chains to more compact face–face (FF) contacts densifying the aggregates with increased settling rates. During settling, the sponge-like network structure with EE and FF string-like aggregates, limits dewatering because the steric effects in the resulting partially-gelled aggregate structures are dominant. With flocculant addition, the internal structure and networking of the pre-aggregates is largely preserved but they are rapidly and effectively bound together by the aggregate-bridging action of the flocculant. The effects of initial pH and Ca ion addition on these structures are also analyzed. Statistical analysis from cryo-SEM imaging shows that there is an inverse correlation of intra-aggregate porosity with Darcian inter-aggregate permeability whereas there is a strong positive correlation of Darcian permeability with settling and primary dewatering rate as a function of pH in suspension. Graphs of partial void contributions also suggest that it is not total porosity that dominates permeability in these systems but the abundance of larger intra-aggregate voids

    Using Activated Carbon Electrode in Electrosorptive Deionisation of Brackish Water

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    The electrosorptive deionisation process has been investigated to develop the technology into a system for desalination. Experiments have been conducted in a reactor system and it has been found that the activated carbon has some deionisation capacity due to its very high adsorption capacity and conductivity, so it can be used as an alternative electrode material. Surface modifications have been made to the activated carbon material, including alkaline treatment and loading of titanium dioxide nanoparticles. The specific surface areas (BET), average pore size and total pore volume were analysed by surface area and porosity analyzer. The modified electrode material demonstrated enhanced electrosorption capacity and reduced physical sorption at the pores, so desorption is more efficient. An innovative approach for desorption of the saturated activated carbon electrodes has been tried using ultrasonic vibration and increased temperature, the results of regeneration in water, aided by ultrasonic at 20°C and 50°C are presented as well. Cyclic voltammetry experiments at various scan rates were conducted using a potentiostat to analyse the electrical double-layer capacitance of the activated carbon materials. This preliminary study demonstrated that activated carbon granules have the potential to be cost-effective electrode materials for desalting brackish water. The improvement of the electrosorption efficiency can be achieved by surface modification by chemicals and metal oxide nanoparticles such as TiO2

    Stability of sodium polyphosphate dispersants in mineral processing applications

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    Polyphosphates are commonly used industrially to provide electrostatic stabilisation to mineral and material suspensions. Polyphosphate solutions however have shown instability under processing conditions such as high temperature and acidic pH which may lead to a reduction in dispersion properties when added to mineral or material suspensions. In this study the influence of pH, temperature and divalent cation concentration pre-treatment on polyphosphate dispersion properties is reported. Dispersion properties are determined using rheological suspension analysis. The suspensions investigated are material-based model systems of titania pigment and high purity boehmite. Infrared spectroscopy studies of polyphosphate solutions were undertaken to directly investigate the polyphosphate structure after pre-treatment. The rheological measurements show reduced polyphosphate dispersion properties with reduced pH, increased temperature and at high calcium concentrations which correlate with directly measured and reported changes in the polyphosphate structure. When pH, temperature and high divalent cation concentrations are combined, the synergistic effect on reduced polyphosphate dispersion performance is particularly prominent

    Using Mesoporous Carbon Electrodes for Brackish Water Desalination

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    Electrosorptive deionisation is an alternative process to remove salt ions from the brackish water. The porous carbon materials are used as electrodes. When charged in low voltage electric fields, they possess a highly charged surface that induces adsorption of salt ions on the surface. This process is reversible, so the adsorbed salt ions can be desorbed and the electrode can be reused. In the study, an ordered mesoporous carbon (OMC) electrode was developed for electrosorptive desalination. The effects of pore arrangement pattern (ordered and random) and pore size distribution (mesopores and micropores) on the desalination performance was investigated by comparing OMC and activated carbon (AC). It were revealed from X-ray diffraction and N2 sorption measurements that AC has both micropores and mesopores, whereas ordered mesopores are dominant in OMC. Their performance as potential electrodes to remove salt was evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests at a range of electrolyte concentrations and sweep rates. It is deduced that under the same electrochemical condition the specific capacitance values of OMC electrode (i.e. 133 F/g obtained from CVat a sweep rate of 1 mV/s in 0.1M NaCl solution) are larger than those of AC electrode (107 F/g), suggesting that the former has a higher desalting capacity than the latter. Furthermore, the OMC electrode shows a better rate capacity than the AC electrode. In addition, the desalination capacities were quantified by the batch-mode experiment at low voltage of 1.2V in 25ppm NaCl solution (50 ms/cm conductivity). It was found that the adsorbed ion amounts of OMC and AC electrodes were 11.6 and 4.3 mmol/g, respectively. The excellent electrosorptive desalination performance of OMC electrode might be not only due to the suitable pore size (average of 3.3 nm) for the propagation of the salt ions, but also due to the ordered mesoporous structure that facilitates desorption of the salt. Based on the results, it was found that the development of an ordered mesoporous structure and the control of the number of micropores are two important strategies for optimising electrode material properties for electrosorptive deionisation
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