241 research outputs found

    Introduced Cyprinid (carp) fishes in Western Australia and their management implications

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    Australia has no native cyprinid species and five introduced species have established self-sustaining populations. This study examines the cyprinid species present in Western Australia and estimates their distribution. The potential for introduced cyprinids to cause environmental impacts is explained and ameliorative action recommended. The presence and distribution of cyprinid species is assessed by examination of museum records, published literature, reported collections, anecdotal evidence and sampling of wetland habitats. Two species, Carassius nuratus (Goldfish) and Cyprinus carpio (Koi carp) are believed to have established populations and a map of estimated distribution is compiled. The capacity for introduced carp to undergo sudden population explosions, long after initial introduction, has been clearly displayed in New Zealand and in the eastern states of Australia. Carp\u27s unique biological and morphological characteristics are examined and the capacity for these characteristics to lead to wider dispersal and environmental impacts in Western Australian wetlands is assessed. The assessment is supplemented by a literature review and a compiled bibliography of published Australian research literature. Principles of effective management of cyprinid populations are discussed and recommendations for amelioration of potential impacts is provided. This is a preliminary study and suggests further avenues of essential research

    Modification of bacterial cell membrane to accelerate decolorization of textile wastewater effluent using microbial fuel cells: role of gamma radiation

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    The aim of the present work was to increase bacterial adhesion on anode via inducing membrane modifications to enhance textile wastewater treatment in Microbial Fuel Cell (MFC). Real textile wastewater was used in mediator-less MFCs for bacterial enrichment. The enriched bacteria were pre-treated by exposure to 1 KGy gamma radiation and were tested in MFC setup. Bacterial cell membrane permeability and cell membrane charges were measured using noninvasive dielectric spectroscopy measurements. The results show that pre-treatment using gamma radiation resulted in biofilm formation and increased cell permeability and exopolysaccharide production; this was reflected in both MFC performance (average voltage 554.67 mV) and decolorization (96.42%) as compared to 392.77 mV and 60.76% decolorization for non-treated cells. At the end of MFC operation, cytotoxicity test was performed for treated wastewater using a dermal cell line, the results obtained show a decrease in toxicity from 24.8 to 0 (v/v%) when cells were exposed to gamma radiation. Fourier-transform infrared (FTIR) spectroscopy showed an increase in exopolysaccharides in bacterial consortium exposed to increasing doses of gamma radiation suggesting that gamma radiation increased exopolysaccharide production, providing transient media for electron transfer and contributing to accelerating MFC performance. Modification of bacterial membrane prior to MFC operation can be considered highly effective as a pre-treatment tool that accelerates MFC performance

    Group descent algorithms for nonconvex penalized linear and logistic regression models with grouped predictors

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    Penalized regression is an attractive framework for variable selection problems. Often, variables possess a grouping structure, and the relevant selection problem is that of selecting groups, not individual variables. The group lasso has been proposed as a way of extending the ideas of the lasso to the problem of group selection. Nonconvex penalties such as SCAD and MCP have been proposed and shown to have several advantages over the lasso; these penalties may also be extended to the group selection problem, giving rise to group SCAD and group MCP methods. Here, we describe algorithms for fitting these models stably and efficiently. In addition, we present simulation results and real data examples comparing and contrasting the statistical properties of these methods

    Design of a single chamber air cathode microbial fuel cell using a stainless steel spiral anode and 3D printing techniques for continuous flow dye decolourisation

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    Microbial fuel cells (MFC) offer a novel solution in wastewater treatment systems. Their capacity for COD removal and concomitant electricity generation are highly attractive properties for reducing costs & environmental impacts in industry. MFCs require expensive membranes & catalysts such as Nafion and platinum respectively to achieve increased power output, but the cost of these materials is prohibitive for real world applications. An air breathing, 1 litre-scale spiral anode MFC was designed (Fig. 1) to provide a high electrode surface area to reactor volume ratio using commonly and cheaply available materials such as stainless steel and activated carbon. Non-platinum group metal catalysts (FeAAPyr family) were integrated into a PVDF cathode fabricated using single step phase inversion to improve rate of the oxygen reduction reaction. Anode surface area was maximized by concertina folding and spiral arrangement and its surface was modified using sulphuric acid, heat treatment & carbon black adsorption to provide a more biocompatible surface for biofilms. The performance characteristics of the designed MFC are currently being investigated. Decolourisation of Acid orange-7 azo dye & COD removal were initially investigated in recirculating batch mode followed by continuous flow configuration with a hydraulic retention time of 36 hours. Optimisation of hydraulic retention times, cathode construction & anode surface modification will present a feasible system for the scale up of microbial fuel cells for industrial use, maximizing COD removal & electricity production

    Degradation of azo dyes (Acid orange 7) in a microbial fuel cell: comparison between anodic microbial-mediated reduction and cathodic laccase-mediated oxidation

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    Microbial fuel cells (MFCs) are a promising technology for the simultaneous treatment of wastewater and electricity production. With regard to azo-dye containing wastewater (e.g. from textile manufacturing), the dyes may be fed via the anode chamber containing electrochemically active bacteria or via the cathode chamber containing laccase enzyme as catalyst for oxygen reduction. This study investigated which of the two approaches is the best with regard to rate of decolourisation of the dye (Acid orange 7), COD reduction and electricity production. The power density was higher for the MFCdye at cathode (25 mW/m2, COD reduction 80%) compared with 18 mW/m2 (COD reduction 69%) for MFCdye at anode (Shewanella oneidensis as catalyst). The decolourisation rate of the dye was not statistically significant between the two approaches with ca. 75% decolourisation achieved in 24 h. The anodic dye degradation products were unstable when exposed to air resulting in what seems to be induced diazotization and regaining of colour. In case of degradation by laccase in the cathode chamber, the decolourisation products were stable and simpler in chemical structure (e.g. presence of aliphatic compounds) as determined by GC-MS. This work suggests that feeding azo dyes in cathode chambers of MFCs containing laccase is a better way of treating the dyes than the commonly used approach of feeding the dye in the anode chamber

    Energy harvesting from Microbial Fuel Cells – Wastewater to Electricity

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    MFCs have the potential to revolutionise wastewater treatment and catalyse a change in attitude towards wastewater as a commodity. It has been observed that domestic wastewater contains approximately 7.6 kJ/L of energy (Heidrich et al., 2011). In large-scale settings, wastewater could be used as an energy resource, offering huge savings in terms of cost and environmental burden. The major challenges facing the implementation of MFCs into wastewater treatment are scale up and energy harvesting/storage. In this study, a modular 20L air-breathing microbial fuel cell was developed alongside a smart energy harvesting (EH) system incorporating AI. The 20L air breathing MFC consists of modular cathode cassettes that enables easy maintenance and scale up to suit adaptive or changing end user requirements. PVDF/Stainless steel mesh cathodes are fabricated using phase inversion and oxygen reduction reaction catalysts incorporated in the polymeric matrix. Custom made carbon fibre brush electrodes are utilised as anodes. The system was inoculated with Shewanella Oneidensis MR-1 and ran under recirculating batch conditions. The MFC is monitored and controlled by a purpose-built circuit that tracks the performance of the individual cathode cassettes and configures the system via a custom Maximum Power Point Tracking (MPPT) algorithm for the best efficiency available for the given conditions. In addition, the circuit stores the extracted energy in a suitable energy storage element such as a capacitor bank or a rechargeable battery pack, with optimum charging levels. Moreover, the system is capable of learning multiple parameters associated with the MFC to optimise its parameters to maintain its high efficiency. The harvested energy can be used to power various types of electronic devices through the circuit's variable/adjustable power output. Heidrich, E., Curtis, T. and Dolfing, J. (2011). Determination of the Internal Chemical Energy of Wastewater. Environmental Science & Technology, 45 (2), 827-832. Available from 10.1021/es103058w

    Early Laser for Burn Scars (ELABS): protocol for a multi-centre randomised, controlled trial of both the effectiveness and cost-effectiveness of the treatment of hypertrophic burn scars with Pulsed Dye Laser and standard care compared to standard care alone [version 1; peer review: 2 approved]

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    This paper outlines the protocol for a study that is being carried out at multiple centres across the UK in the next three years. It is a Research for Patient Benefit (RfPB) study funded by the National Institute for Healthcare Research (NIHR). The aim is to assess the effectiveness of treating hypertrophic burns scars with pulsed dye laser (PDL) at an early stage of scar formation. The objective is to improve Quality of Life for the patient by improving both the appearance and quality of burn scarring, as well as reducing its psychological impact. This is a parallel-arm randomised, controlled trial to compare PDL and standard care against standard care alone. The difference is measured between baseline and six-month follow-up. Recruits are within three months of healing from a burn injury; with wounds showing a defined potential for hypertrophic scarring. A total of 120 patients are recruited in a multi-centre study; with randomisation in a 1:1 allocation to each arm. The treatment arm receives 3 PDL treatments at six-week intervals in addition to standard care, whereas the control arm receives standard care alone. The primary outcome is the patient-rated part of the Patient and Observer Scar Scale (POSAS). Psychological and psycho-social impact is evaluated using the CARe burn scale (UWE, Bristol) and Quality Adjusted Life Years (QALY) is determined using the Short-Form Health Survey (SF-12). The study evaluates both the cost-effectiveness through an economic analysis and the patient-reported experience of the treatment by phone interviews

    Study protocol for First Dental Steps Intervention: feasibility study of a health visitor led infant oral health improvement programme.

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    BACKGROUND: Dental caries in childhood is a burden on the daily lives of children and their families, and associated with poor oral health in adulthood. In England, dental caries is the most common reason for young children to be admitted to hospital. It is believed that most tooth extractions (due to decay) for children aged 10 years and under, could be avoided with improved prevention and early management. National public health policy recommendations in England include specific oral health initiatives to tackle tooth decay. One of these initiatives is delivered as part of the Healthy Child Programme and includes providing workforce training in oral health, integrating oral health advice into home visits, and the timely provision of fluoride toothpaste. This protocol seeks to assess the delivery of the First Dental Steps intervention and uncertainties related to the acceptability, recruitment, and retention of participants. METHODS: This study seeks to explore the feasibility and acceptability of the First Dental Steps intervention and research methods. First Dental Steps intervention will be delivered in local authority areas in South West England and includes oral health training for health visitors (or community nursery nurses) working with 0-5-year-olds and their families. Further, for vulnerable families, integrating oral health advice and the provision of an oral health pack (including a free flow cup, an age appropriate toothbrush, and 1450 ppm fluoride toothpaste) during a mandated check by a health visitor. In this study five local authority areas will receive the intervention. Interviews with parents receiving the intervention and health visitors delivering the intervention will be undertaken, along with a range of additional interviews with stakeholders from both intervention and comparison sites (four additional local authority areas). DISCUSSION: This protocol was written after the start of the COVID-19 pandemic, as a result, some of the original methods were adjusted specifically to account for disruptions caused by the pandemic. Results of this study will primarily provide evidence on the acceptability and feasibility of both the First Dental Steps intervention and the research methods from the perspective of both families and stakeholders
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