12,493 research outputs found

    Battery SMART charge controller/combined co-gen grid connected inverter design and simulation

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    Electricity generation and distribution is undergoing significant change under the influences of energy security, climate change, technological development, and economics. Technologies that have introduced two-way power flow onto a distribution grid that was designed for one-way power flow are creating challenges and opportunities for innovation in the electricity distribution sector. These technologies include solar photovoltaics (PV), wind turbines, and battery energy storage systems (BESS). As the newest technology, BESS present opportunities to both the electricity distribution network service provider (DNSP) and the consumer. This dissertation focused primarily on the consumer side of the switchboard, modelling and analysing the economics and some of the technical issues for an economic-mediated battery controller as part of a grid-tied residential hybrid renewable energy system (HRES) that consists of a BESS, 1 kW wind turbine, and 10 kW PV array. The geographical context of this project is Nambour, Queensland; PV and wind power calculations were based on Nambour’s meteorological history. Residential energy consumption was modelled as a ‘typical’ Nambour residential customer. The technological context was such that costs and choices applied at mid-2016. The tariff context used was the recently introduced TOU tariff 12, which played a significant role in the timing and logic development of the battery charge controller algorithm. From a technical standpoint, the charge controller algorithm was a major achievement of the present work. In developing the algorithm, it was found that the use of data from individual system components could be used to formulate the optimum mix of power sourced from or sunk to both the grid and the BESS. The output of this formulation was then demonstrated as a data input used for the control of the switching patterns of the BESS power electronics, a two-quadrant DC-DC converter (chopper). The other major achievement of the current work was the finding that although BESS economics continue to improve, they generally still need to achieve further cost reductions in order to realise economic feasibility for the modelled context. It was also found that economic feasibility is more likely to be reached more quickly under conditions of high energy consumption, high inflation, high peak TOU tariff, and low discount rate

    Rapid toxicity detection in water quality control utilizing automated multispecies biomonitoring for permanent space stations

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    The objective of this study was to evaluate proposed design characteristics and applications of automated biomonitoring devices for real-time toxicity detection in water quality control on-board permanent space stations. Simulated tests in downlinking transmissions of automated biomonitoring data to Earth-receiving stations were simulated using satellite data transmissions from remote Earth-based stations

    The first step for neuroimaging data analysis: DICOM to NIfTI conversion

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    BACKGROUND: Clinical imaging data are typically stored and transferred in the DICOM format, whereas the NIfTI format has been widely adopted by scientists in the neuroimaging community. Therefore, a vital initial step in processing the data is to convert images from the complicated DICOM format to the much simpler NIfTI format. While there are a number of tools that usually handle DICOM to NIfTI conversion seamlessly, some variations can disrupt this process. NEW METHOD: We provide some insight into the challenges faced with image conversion. First, different manufacturers implement the DICOM format differently which complicates the conversion. Second, different modalities and sub-modalities may need special treatment during conversion. Lastly, the image transferring and archiving can also impact the DICOM conversion. RESULTS: We present results in several error-prone domains, including the slice order for functional imaging, phase encoding direction for distortion correction, effect of diffusion gradient direction, and effect of gantry correction for some imaging modality. COMPARISON WITH EXISTING METHODS: Conversion tools are often designed for a specific manufacturer or modality. The tools and insight we present here are aimed at different manufacturers or modalities. CONCLUSIONS: The imaging conversion is complicated by the variation of images. An understanding of the conversion basics can be helpful for identifying the source of the error. Here we provide users with simple methods for detecting and correcting problems. This also serves as an overview for developers who wish to either develop their own tools or adapt the open source tools created by the authors

    'Seizure First Aid Training' for people with epilepsy who attend emergency departments, and their family and friends: study protocol for intervention development and a pilot randomised controlled trial.

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    INTRODUCTION: People with chronic epilepsy (PWE) often make costly but clinically unnecessary emergency department (ED) visits. Offering them and their carers a self-management intervention that improves confidence and ability to manage seizures may lead to fewer visits. As no such intervention currently exists, we describe a project to develop and pilot one. METHODS AND ANALYSIS: To develop the intervention, an existing group-based seizure management course that has been offered by the Epilepsy Society within the voluntary sector to a broader audience will be adapted. Feedback from PWE, carers and representatives from the main groups caring for PWE will help refine the course so that it addresses the needs of ED attendees. Its behaviour change potential will also be optimised. A pilot randomised controlled trial will then be completed. 80 PWE aged ≥16 who have visited the ED in the prior 12 months on ≥2 occasions, along with one of their family members or friends, will be recruited from three NHS EDs. Dyads will be randomised to receive the intervention or treatment as usual alone. The proposed primary outcome is ED use in the 12 months following randomisation. For the pilot, this will be measured using routine hospital data. Secondary outcomes will be measured by patients and carers completing questionnaires 3, 6 and 12 months postrandomisation. Rates of recruitment, retention and unblinding will be calculated, along with the ED event rate in the control group and an estimate of the intervention's effect on the outcome measures. ETHICS AND DISSEMINATION: Ethical approval: NRES Committee North West-Liverpool East (Reference number 15/NW/0225). The project's findings will provide robust evidence on the acceptability of seizure management training and on the optimal design of a future definitive trial. The findings will be published in peer-reviewed journals and presented at conferences. TRIAL REGISTRATION NUMBER: ISRCTN13 871 327

    Predictive Modeling in Post-reform Marketplace

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    Healthcare reform changes everything. Annual and lifetime dollar limits, underwriting, and preexisting condition exclusion will all be eliminated by 2014. Insurers must offer coverage to any individual regardless of their health status. An overwhelming majority of those who will be mandated to purchase individual insurance is currently uninsured or under-insured. Insurers have insufficient internal data to estimate costs for this new population. A study on how to apply predictive modeling to deal with risks and uncertainties facing healthcare industry in the post-reform marketplace is presented in this article

    Blocking two-component signalling enhances Candida albicans virulence and reveals adaptive mechanisms that counteract sustained SAPK activation

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    This work was funded by the UK Biotechnology and Biological Research Council [www.bbsrc.ac.uk] JQ (BB/K016393/1); AJPB (BB/K017365/1). The work was also supported by the Wellcome Trust [www.wellcome.ac.uk], JQ (086048, 097377); AJPB (097377)); LPE (097377). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Crystal structure of monomeric human β-2- microglobulin reveals clues to its amyloidogenic properties

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    Dissociation of human β-2-microglobulin (β(2)m) from the heavy chain of the class I HLA complex is a critical first step in the formation of amyloid fibrils from this protein. As a consequence of renal failure, the concentration of circulating monomeric β(2)m increases, ultimately leading to deposition of the protein into amyloid fibrils and development of the disorder, dialysis-related amyloidosis. Here we present the crystal structure of a monomeric form of human β(2)m determined at 1.8-Å resolution that reveals remarkable structural changes relative to the HLA-bound protein. These involve the restructuring of a β bulge that separates two short β strands to form a new six-residue β strand at one edge of this β sandwich protein. These structural changes remove key features proposed to have evolved to protect β sheet proteins from aggregation [Richardson, J.&Richardson, D. (2002) Proc. Natl. Acad. Sci. USA 99, 2754–2759] and replaces them with an aggregationcompetent surface. In combination with solution studies using (1)H NMR, we show that the crystal structure presented here represents a rare species in solution that could provide important clues about the mechanism of amyloid formation from the normally highly soluble native protein

    11 beta-hydroxysteroid dehydrogenase type 1 regulates glucocorticoid-induced insulin resistance in skeletal muscle

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    OBJECTIVE: Glucocorticoid excess is characterized by increased adiposity, skeletal myopathy, and insulin resistance, but the precise molecular mechanisms are unknown. Within skeletal muscle, 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts cortisone (11-dehydrocorticosterone in rodents) to active cortisol (corticosterone in rodents). We aimed to determine the mechanisms underpinning glucocorticoid-induced insulin resistance in skeletal muscle and indentify how 11beta-HSD1 inhibitors improve insulin sensitivity. \ud RESEARCH DESIGN AND METHODS: Rodent and human cell cultures, whole-tissue explants, and animal models were used to determine the impact of glucocorticoids and selective 11beta-HSD1 inhibition upon insulin signaling and action. \ud RESULTS: Dexamethasone decreased insulin-stimulated glucose uptake, decreased IRS1 mRNA and protein expression, and increased inactivating pSer307^{307} insulin receptor substrate (IRS)-1. 11beta-HSD1 activity and expression were observed in human and rodent myotubes and muscle explants. Activity was predominantly oxo-reductase, generating active glucocorticoid. A1 (selective 11beta-HSD1 inhibitor) abolished enzyme activity and blocked the increase in pSer307^{307} IRS1 and reduction in total IRS1 protein after treatment with 11DHC but not corticosterone. In C57Bl6/J mice, the selective 11beta-HSD1 inhibitor, A2, decreased fasting blood glucose levels and improved insulin sensitivity. In KK mice treated with A2, skeletal muscle pSer307^{307} IRS1 decreased and pThr308^{308} Akt/PKB increased. In addition, A2 decreased both lipogenic and lipolytic gene expression.\ud CONCLUSIONS: Prereceptor facilitation of glucocorticoid action via 11beta-HSD1 increases pSer307^{307} IRS1 and may be crucial in mediating insulin resistance in skeletal muscle. Selective 11beta-HSD1 inhibition decreases pSer307^{307} IRS1, increases pThr308^{308} Akt/PKB, and decreases lipogenic and lipolytic gene expression that may represent an important mechanism underpinning their insulin-sensitizing action

    Fatigue behavior of Ilizarov frame versus tibial interlocking nail in a comminuted tibial fracture model: a biomechanical study

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    BACKGROUND: Treatment options for comminuted tibial shaft fractures include plating, intramedullary nailing, and external fixation. No biomechanical comparison between an interlocking tibia nail with external fixation by an Ilizarov frame has been reported to date. In the present study, we compared the fatigue behaviour of Ilizarov frames to interlocking intramedullary nails in a comminuted tibial fracture model under a combined loading of axial compression, bending and torsion. Our goal was to determine the biomechanical characteristics, stability and durability for each device over a clinically relevant three month testing period. The study hypothesis was that differences in the mechanical properties may account for differing clinical results and provide information applicable to clinical decision making for comminuted tibia shaft fractures. METHODS: In this biomechanical study, 12 composite tibial bone models with a comminuted fracture and a 25 mm diaphyseal gap were investigated. Of these, six models were stabilized with a 180-mm four-ring Ilizarov frame, and six models were minimally reamed and stabilized with a 10 mm statically locked Russell-Taylor Delta™ tibial nail. After measuring the pre-fatigue axial compression bending and torsion stiffness, each model was loaded under a sinusoidal cyclic combined loading of axial compression (2.8/28 lbf; 12.46/124.6 N) and torque (1.7/17 lbf-in; 0.19/1.92 Nm) at a frequency of 3 Hz. The test was performed until failure (implant breakage or ≥ 5° angulations and/or 2 cm shortening) occurred or until 252,000 cycles were completed, which corresponds to approximately three months testing period. RESULTS: In all 12 models, both the Ilizarov frame and the interlocking tibia nail were able to maintain fracture stability of the tibial defect and to complete the full 252,000 cycles during the entire study period of three months. A significantly higher stiffness to axial compression and torsion was demonstrated by the tibial interlocking nail model, while the Ilizarov frame provided a significantly increased range of axial micromotion. CONCLUSION: This is the first study, to our knowledge, which compares the biomechanical properties of an intramedullary nail to an external Ilizarov frame to cyclic axial loading and torsion in a comminuted tibia shaft fracture model. Prospective, randomized trials comparing Ilizarov frames and interlocked tibial nails are needed to clarify the clinical impact of these biomechanical findings

    "We also deserve help during the pandemic": The effect of the COVID-19 pandemic on foreign domestic workers in Hong Kong.

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    The coronavirus disease 2019 (COVID-19) pandemic poses particular challenges for migrant workers around the world. This study explores the unique experiences of foreign domestic workers (FDWs) in Hong Kong, and how COVID-19 impacted their health and economic wellbeing. Interviews with FDWs (n = 15) and key informants (n = 3) were conducted between May and August 2020. FDWs reported a dual-country experience of the pandemic, where they expressed concerns about local transmission risks as well as worries about their family members in their home country. Changes to their current work situation included how their employers treated them, as well as their employment status. FDWs also cited blind spots in the Hong Kong policy response that also affected their experience of the pandemic, including a lack of support from the Hong Kong government. Additional support is needed to mitigate the particularly negative effects of the pandemic on FDWs
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