3,152 research outputs found

    Factors Influencing Revenue Collection for Preventative Maintenance of Community Water Systems: A Fuzzy-Set Qualitative Comparative Analysis

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    This study analyzed combinations of conditions that influence regular payments for water service in resource-limited communities. To do so, the study investigated 16 communities participating in a new preventive maintenance program in the Kamuli District of Uganda under a public–private partnership framework. First, this study identified conditions posited as important for collective payment compliance from a literature review. Then, drawing from data included in a water source report and by conducting semi-structured interviews with households and water user committees (WUC), we identified communities that were compliant with, or suspended from, preventative maintenance service payments. Through qualitative analyses of these data and case knowledge, we identified and characterized conditions that appeared to contribute to these outcomes. Then, we employed fuzzy-set qualitative comparative analysis (fsQCA) to determine the combinations of conditions that led to payment compliance. Overall, the findings from this study reveal distinct pathways of conditions that impact payment compliance and reflect the multifaceted nature of water point sustainability. Practically, the findings identify the processes needed for successful payment compliance, which include a strong WUC with proper support and training, user perceptions that the water quality is high and available in adequate quantities, ongoing support, and a lack of nearby water sources. A comprehensive understanding of the combined factors that lead to payment compliance can improve future preventative maintenance programs, guide the design of water service arrangements, and ultimately increase water service sustainability

    Serotonin signaling through the 5-HT1B receptor and NADPH oxidase 1 in pulmonary arterial hypertension

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    Objective: Serotonin can induce human pulmonary artery smooth muscle cell (hPASMC) proliferation through reactive oxygen species (ROS), influencing the development of pulmonary arterial hypertension (PAH). We hypothesise that in PASMCs, serotonin induces oxidative stress through NADPH-oxidase-derived ROS generation and reduced Nrf-2 anti-oxidant systems, promoting vascular injury. Approach and Results: HPASMCs from controls and PAH patients, and PASMCs from Nox1-/- mice, were stimulated with serotonin in the absence/presence of inhibitors of Src kinase, the 5-HT1B receptor and NADPH oxidase 1 (Nox1). Markers of fibrosis were also determined. The pathophysiological significance of our findings was examined in vivo in serotonin transporter overexpressing (SERT+) female mice, a model of pulmonary hypertension (PH). We confirmed serotonin increased superoxide and H2O2 production in these cells. For the first time, we show that serotonin increased oxidized protein tyrosine phosphatases and peroxiredoxin-SO3H and decreased Nrf-2 and catalase activity in hPASMCs. ROS generation was exaggerated, and dependent on c-Src, 5-HT1B receptor and the serotonin transporter in PAH-hPASMCs. Proliferation and extracellular matrix remodeling were exaggerated in PAH-hPASMCs and dependent on 5-HT1B receptor signaling and Nox1, confirmed in PASMCs from Nox1-/- mice. In SERT+ mice, SB216641, a 5-HT1B receptor antagonist, prevented development of PH in a ROS-dependent manner. Conclusions: Serotonin can induce c-Src-regulated Nox1-induced ROS and Nrf-2 dysregulation, contributing to increased post-translational oxidative modification of proteins, activation of redox-sensitive signaling pathways in hPASMCs; associated with mitogenic responses. 5-HT1B receptors contribute to experimental PH by inducing lung ROS production. Our results suggest 5-HT1B receptor-dependent c-Src-Nox1-pathways contribute to vascular remodeling in PAH

    Kinetic Modeling of Transesterification of Triacetin Using Synthesized Ion Exchange Resin (SIERs)

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    Strong anion exchange resins with QN+OH-, have the potential to be developed and employed as heterogeneous catalyst for transesterification, as they are chemically stable to leaching of the functional group. Nine different SIERs (SIER1-9) with QN + OH were prepared by suspension polymerization of vinylbenzyl chloridedivinylbenzene (VBC-DVB) copolymers in the presence of n-heptane (pore-forming agent). The amine group was successfully grafted into the polymeric resin beads through functionalization with trimethylamine. These SIERs are then used as a catalyst for the transesterification of triacetin with methanol. A set of differential equations that represents the Langmuir-Hinshelwood-HougenWatson (LHHW) and Eley-Rideal (ER) models for the transesterification reaction were developed. These kinetic models of LHHW and ER were fitted to the experimental data. Overall, the synthesized ion exchange resin-catalyzed reaction were welldescribed by the Eley-Rideal model compared to LHHW models, with sum of square error (SSE) of 0.742 and 0.996, respectively

    Vascular dysfunction and fibrosis in stroke-prone spontaneously hypertensive rats: the aldosterone-mineralocorticoid receptor-Nox1 Axis

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    Aims: We questioned whether aldosterone and oxidative stress play a role in vascular damage in severe hypertension and investigated the role of Nox1 in this process. Materials and methods: We studied mesenteric arteries, aortas and vascular smooth muscle cells (VSMC) from WKY and SHRSP rats. Vascular effects of eplerenone or canrenoic acid (CA) (mineralocorticoid receptor (MR) blockers), ML171 (Nox1 inhibitor) and EHT1864 (Rac1/2 inhibitor) were assessed. Nox1-knockout mice were also studied. Vessels and VSMCs were probed for Noxs, reactive oxygen species (ROS) and pro-fibrotic/inflammatory signaling. Key findings: Blood pressure and plasma levels of aldosterone and galectin-3 were increased in SHRSP versus WKY. Acetylcholine-induced vasorelaxation was decreased (61% vs 115%) and phenylephrine-induced contraction increased in SHRSP versus WKY (Emax 132.8% vs 96.9%, p < 0.05). Eplerenone, ML171 and EHT1864 attenuated hypercontractility in SHRSP. Vascular expression of collagen, fibronectin, TGFβ, MCP-1, RANTES, MMP2, MMP9 and p66Shc was increased in SHRSP versus WKY. These changes were associated with increased ROS generation, 3-nitrotyrosine expression and Nox1 upregulation. Activation of vascular p66Shc and increased expression of Nox1 and collagen I were prevented by CA in SHRSP. Nox1 expression was increased in aldosterone-stimulated WKY VSMCs, an effect that was amplified in SHRSP VSMCs (5.2vs9.9 fold-increase). ML171 prevented aldosterone-induced VSMC Nox1-ROS production. Aldosterone increased vascular expression of fibronectin and PAI-1 in wild-type mice but not in Nox1-knockout mice. Significance: Our findings suggest that aldosterone, which is increased in SHRSP, induces vascular damage through MR-Nox1-p66Shc-mediated processes that modulate pro-fibrotic and pro-inflammatory signaling pathways

    Temporal tensions: EU citizen migrants, asylum seekers and refugees navigating dominant temporalities of work in England

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    This article considers the role of temporality in the differential inclusion of migrants. In order to do this we draw on research which examined the working lives of a diverse group of new migrants in North East England: Eastern European migrants arriving from 2004 and asylum seekers and refugees arriving from 1999. In so doing we emphasise both distinct and shared experiences, related to immigration status but also a range of other dimensions of identity. We specifically consider how dominant temporalities regulate the lives of new migrants through degrees, periods and moments of acceleration/deceleration. The paper illustrates the ways in which dominant temporalities control access and non-access to particular, often precarious forms of work – but also how migrants attempt to navigate such restrictions through their own use and constructions of time. We explore this in relation to three 'phases' of time. Firstly, through experiences of the UK asylum system and work prohibition. Secondly for a broader group of participants we explore the speeding up and slowing down of transitions to and progression within work. Lastly, we consider how participants experience everyday temporal tensions between paid employment and unpaid care. Across these phases we suggest that dominant orderings of time and the narratives which make sense of these, represent non-simultaneous temporalities that do not neatly map onto each other

    Combining continuous flow oscillatory baffled reactors and microwave heating: Process intensification and accelerated synthesis of metal-organic frameworks

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    We have constructed a continuous flow oscillatory baffled reactor (CF-OBR) equipped with a homogeneous and controllable microwave applicator in an entirely novel design. This affords a new route to chemical production incorporating many of the principles of process intensification and allows, for the first time, investigation of the synergistic benefits of microwave heating and CF-OBRs such as; faster and continuous processing; improved product properties and purity; improved control over the processing parameters; and reduced energy consumption. The process is demonstrated by the production of a metal-organic framework (MOF), HKUST-1, a highly porous crystalline material with potential applications in gas storage and separation, catalysis, and sensing. Our reactor enabled the production of HKUST-1 at the 97.42 g/h scale, with a space time yield (STY) of 6.32 × 105 kg/m3/day and surface area production rate (SAPR) of 1.12 × 1012 m2/m3/day. This represents the highest reported STY and fastest reported synthesis (2.2 seconds) for any MOF produced via any method to-date and is an improvement on the current SAPR for HKUST-1 by two orders of magnitude owing to the superior porosity exhibited by HKUST-1 produced using our rig (Langmuir surface area of 1772 compared to 600 m2/g)

    Experimental Determination of Optimal Conditions for Reactive Coupling of Biodiesel Production With in situ Glycerol Carbonate Formation in a Triglyceride Transesterification Process

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    This study investigated a reactive coupling to determine the optimal conditions for transesterification of rapeseed oil (RSO) to fatty acid methyl ester (FAME) and glycerol carbonate (GLC) in a one-step process, and at operating conditions which are compatible with current biodiesel industry. The reactive coupling process was studied by transesterification of RSO with various molar ratios of both methanol and dimethyl carbonate (DMC), using triazabicyclodecene (TBD) guanidine catalyst and reaction temperatures of 50–80°C. The optimal reaction conditions obtained, using a Design of Experiments approach, were a 2:1 methanol-to-RSO molar ratio and 3:1 DMC-to-RSO molar ratio at 60°C. The FAME and GLC conversions at the optimal conditions were 98.0 ± 1.5 and 90.1 ± 2.2%, respectively, after 1 h reaction time using the TBD guanidine catalyst. Increase in the DMC-to-RSO molar ratio from 3:1 to 6:1 slightly improved the GLC conversion to 94.1 ± 2.8% after 2 h, but this did not enhance the FAME conversion. Methanol substantially improved both FAME and GLC conversions at 1:1–2:1 methanol-to-RSO molar ratios and enhanced the GLC separation from the reaction mixture. It was observed that higher methanol molar ratios (>3:1) enhanced only FAME yields and resulted in lower GLC conversions due to reaction equilibrium limitations. At a 6:1 methanol-to-RSO molar ratio, 98.4% FAME and 73.3% GLC yields were obtained at 3:1 DMC-to-RSO molar ratio and 60°C. This study demonstrates that formation of low value crude glycerol can be reduced by over 90% compared to conventional biodiesel production, with significant conversion to GLC, a far more valuable product

    Vascular endothelial growth factor (VEGF) expression in locally advanced prostate cancer: secondary analysis of radiation therapy oncology group (RTOG) 8610.

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    BACKGROUND: Angiogenesis is a key element in solid-tumor growth, invasion, and metastasis. VEGF is among the most potent angiogenic factor thus far detected. The aim of the present study is to explore the potential of VEGF (also known as VEGF-A) as a prognostic and predictive biomarker among men with locally advanced prostate cancer. METHODS: The analysis was performed using patients enrolled on RTOG 8610, a phase III randomized control trial of radiation therapy alone (Arm 1) versus short-term neoadjuvant and concurrent androgen deprivation and radiation therapy (Arm 2) in men with locally advanced prostate carcinoma. Tissue samples were obtained from the RTOG tissue repository. Hematoxylin and eosin slides were reviewed, and paraffin blocks were immunohistochemically stained for VEGF expression and graded by Intensity score (0-3). Cox or Fine and Gray\u27s proportional hazards models were used. RESULTS: Sufficient pathologic material was available from 103 (23%) of the 456 analyzable patients enrolled in the RTOG 8610 study. There were no statistically significant differences in the pre-treatment characteristics between the patient groups with and without VEGF intensity data. Median follow-up for all surviving patients with VEGF intensity data is 12.2 years. Univariate and multivariate analyses demonstrated no statistically significant correlation between the intensity of VEGF expression and overall survival, distant metastasis, local progression, disease-free survival, or biochemical failure. VEGF expression was also not statistically significantly associated with any of the endpoints when analyzed by treatment arm. CONCLUSIONS: This study revealed no statistically significant prognostic or predictive value of VEGF expression for locally advanced prostate cancer. This analysis is among one of the largest sample bases with long-term follow-up in a well-characterized patient population. There is an urgent need to establish multidisciplinary initiatives for coordinating further research in the area of human prostate cancer biomarkers
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