148 research outputs found

    Thermal Performance Analysis of an Underground Closed Chamber with Human Body Heat Sources under Natural Convection

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    In this article, a combined experimental and numerical study has been performed to investigate the thermal performance of a mine refuge chamber (MRC) under natural convection. In the current study, a 20-hour heating experiment is carried out in a fifty-person MRC laboratory and the heat lamps are utilized to simulate the human heat loss. A new analytical model is proposed to predict the air temperature and validated against the experimental data. Sensitivity analysis is performed to further investigate the effects of the thermal parameters of the rock. Results indicated that: (1) two different air temperature increase stages, rapid and slow increase stages, are observed in the MRC; (2) A new analytical method for predicting the air temperature in MRC under natural convection is proposed, it shows that the air temperature increasing trend becomes slow with the increase of the thermal conductivity, density and specific heat capacity of the rock; (3) the surface heat transfer coefficient on the vertical walls reaches the largest and it increases linearly with air temperature.Peer reviewe

    Protein droplet actuation on superhydrophobic surfaces: A new approach toward anti-biofouling electrowetting systems

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    © 2017 The Royal Society of Chemistry. This is an Open Access article, distributed under the terms of the Creative Commons Attribution 3.0 Unported (CC BY 3.0) licence https://creativecommons.org/licenses/by/3.0/.Among Lab-on-a-chip techniques, Digital microfluidics (DMF), allowing the precise actuation of discrete droplets, is a highly promising, flexible, biochemical assay platform for biomedical and bio-detection applications. However the durability of DMF systems remains a challenge due to biofouling of the droplet-actuating surface when high concentrations of biomolecules are employed. To address this issue, the use of superhydrophobic materials as the actuating surface in DMF devices is examined. The change in contact angle by electrowetting of deionised water and ovalbumin protein samples is characterised on different surfaces (hydrophobic and superhydrophobic). Ovalbumin droplets at 1 mg ml-1 concentration display better electrowetting reversibility on Neverwet®, a commercial superhydrophobic material, than on Cytop®, a typical DMF hydrophobic material. Biofouling rate, characterised by roll-off angle measurement of ovalbumin loaded droplets and further confirmed by measurements of the mean fluorescence intensity of labelled fibrinogen, appears greatly reduced on Neverwet®. Transportation of protein laden droplets (fibrinogen at concentration 0.1 mg ml-1 and ovalbumin at concentration 1 mg ml-1 and 10 mg ml-1) is successfully demonstrated using electrowetting actuation on both single-plate and parallel-plate configurations with performance comparable to that of DI water actuation. In addition, although droplet splitting requires further attention, merging and efficient mixing are demonstrated.Peer reviewe

    The Distributed Annotation System

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    BACKGROUND: Currently, most genome annotation is curated by centralized groups with limited resources. Efforts to share annotations transparently among multiple groups have not yet been satisfactory. RESULTS: Here we introduce a concept called the Distributed Annotation System (DAS). DAS allows sequence annotations to be decentralized among multiple third-party annotators and integrated on an as-needed basis by client-side software. The communication between client and servers in DAS is defined by the DAS XML specification. Annotations are displayed in layers, one per server. Any client or server adhering to the DAS XML specification can participate in the system; we describe a simple prototype client and server example. CONCLUSIONS: The DAS specification is being used experimentally by Ensembl, WormBase, and the Berkeley Drosophila Genome Project. Continued success will depend on the readiness of the research community to adopt DAS and provide annotations. All components are freely available from the project website

    Air Quality Control in Mine Refuge Chamber with Ventilation through Pressure Air Pipeline

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    A combined experimental and numerical study was performed to improve the performance of the ventilation system in a mine refuge chamber (MRC). In the experiment, CO2 cylinders and dispersion pipes were used to simulate the CO2 release of 50 people, and 0.1 L/min per person of fresh air was provided by an air compressor. A new analytical model for a 50-person MRC was proposed and validated against the experimental data. Sensitivity analysis was carried out to investigate the effects of several control factors. The results indicated the following: (1) The ventilation system layout has a significant influence on the CO2 concentration distribution in an MRC, while the uniformity of the CO2 concentration distribution in the MRC may not be effective with increased number of air inlets. (2) Under a well-arranged ventilation system in the 50-person MRC, the average CO2 concentration can be controlled at less than 0.5% with a ventilation rate of 0.1 m3/min per person, and less than 0.2% with a ventilation rate of 0.3 m3/min per person. (3) A quantitative correlation exists between the CO2 concentration and ventilation volume rate, as well as the CO2 release rate, for an MRC under a well-arranged ventilation system.Peer reviewe

    Development of an automated smart trap for wheat pathogens

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    National surveys show fungicide use on wheat continues to increase despite fluctuations in disease pressure, reaching a 30 year high in 2012 (Defra). Septoria tritici is the most significant foliar disease in UK wheat causing between £43M to £53M in yield losses annually; Yellow and brown rust are more sporadic but have caused significant losses during high disease years. In all cases control is by fungicide application costing £82M annually (GFK Kynetec 2013). Effective disease management relies on either prophylactic pesticide use or significant manual intervention and time consuming assessment of crop disease indicators by farmers and agronomists. Furthermore indications are that current levels of pesticide use could lead to increased risk of pesticide resistance, if this should occur it is estimated that wheat yields could reduce by up to 20%. To address this we have developed a prototype integrated and automated spore detection system, designed for unattended field application, to monitor and identify the presence of Septoria, brown and yellow rust. The prototype system incorporates novel cyclonic pathogen collection, on-board sample processing and isothermal DNA amplification chemistry (LAMP). We present the engineering design, optimisation and evaluation of our prototype system reporting on successfully completed laboratory testing and initial field trial results. This prototype will be the basis for the development of a commercially available system which, in addition to inoculum detection, will be capable of providing growers/agronomists with real-time information on inoculum moving into a crop enabling more effective timing and selection of fungicide application, and thus better control, increased yield, and improved environmental stewardship.Peer reviewe

    Design of a high efficiency cyclone for collection of rare and low concentration airborne pathogens

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    Recent serious outbreaks of pathogens such as Chalara Fraxinea, (Ash Dieback) demonstrate the vulnerability of UK’s forests, woods, and trees. Early detection of threats is critical in the fight against such tree pests and pathogens. This requires a process for collecting and analysing the spores which is robust, flexible and can be deployed rapidly, but which also has sufficient sensitivity to detect the earliest precursors. The work presented here describes a newly-developed high-efficiency detection apparatus and is part of an ongoing BBRSC project to improve the UK’s biosecurity. Our automatic spore system is capable of collecting and analysing Chalara Fraxinea using a novel cyclonic pathogen collector. Cyclones are an effective way to separate small particles (spores) from large quantities of surrounding air and store them for analysis. Our system incorporates a purpose-designed high efficiency cyclone directly integrated with a low power custom impeller to maximise volumetric air sampling while minimising the power requirement. 3D printing was used extensively to validate theoretical models and the particle collection and retention capability of this series of prototypes was evaluated experimentally within our Aerosol test chamber. We found that we could collect greater than 90% of particulate in the target size range, thus providing a front-end to a detection platform. Our system is capable of operating autonomously and at low power, with a high sensitivity to ambient particles. The final system design incorporates the use of multiple cyclone storage vessels ensuring complete isolation of each sample, eradicating cross-contamination, and facilitating automated handling of the sample inside the same apparatus. COTS – commercial off the shelf components were incorporated into the cyclone to make a series of cost effective collection vessels. Early collection and detection of pathogens in-situ represents a considerable advance in surveillance and monitoring of pathogens strengthening UK biosecurity for the future.Non peer reviewe

    Sacred communities: contestations and connections

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    This article discusses a project whose purpose was to review existing qualitative and quantitative data from two separate studies to provide new insights about everyday religion and belonging. Researchers engaged in knowledge exchange and dialogue with new and former research participants, with other researchers involved in similar research, and with wider academic networks beyond the core disciplines represented here, principally anthropology and geography. Key concluding themes related to the ambivalent nature of ‘faith’, connections over place and time, and the contested nature of community. Implicit in terms like ‘faith’, ‘community’, and ‘life course’ are larger interwoven narratives of space, time, place, corporeality, and emotion. The authors found that understanding how places, communities, and faiths differ and intersect requires an understanding of social relatedness and boundaries

    Treatment algorithm for infants diagnosed with spinal muscular atrophy through newborn screening

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    Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by the degeneration of alpha motor neurons in the spinal cord, leading to muscular atrophy. SMA is caused by deletions or mutations in the survival motor neuron 1 gene (SMN1). In humans, a nearly identical copy gene, SMN2, is present. Because SMN2 has been shown to decrease disease severity in a dose-dependent manner, SMN2 copy number is predictive of disease severity. To develop a treatment algorithm for SMA-positive infants identified through newborn screening based upon SMN2 copy number. A working group comprised of 15 SMA experts participated in a modified Delphi process, moderated by a neutral third-party expert, to develop treatment guidelines. The overarching recommendation is that all infants with two or three copies of SMN2 should receive immediate treatment (n = 13). For those infants in which immediate treatment is not recommended, guidelines were developed that outline the timing and appropriate screens and tests to be used to determine the timing of treatment initiation. The identification SMA affected infants via newborn screening presents an unprecedented opportunity for achievement of maximal therapeutic benefit through the administration of treatment pre-symptomatically. The recommendations provided here are intended to help formulate treatment guidelines for infants who test positive during the newborn screening process

    Evolution of brown carbon in wildfire plumes

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    Particulate brown carbon (BrC) in the atmosphere absorbs light at subvisible wavelengths and has poorly constrained but potentially large climate forcing impacts. BrC from biomass burning has virtually unknown lifecycle and atmospheric stability. Here, BrC emitted from intense wildfires was measured in plumes transported over 2 days from two main fires, during the 2013 NASA SEAC4RS mission. Concurrent measurements of organic aerosol (OA) and black carbon (BC) mass concentration, BC coating thickness, absorption Ångström exponent, and OA oxidation state reveal that the initial BrC emitted from the fires was largely unstable. Using back trajectories to estimate the transport time indicates that BrC aerosol light absorption decayed in the plumes with a half-life of 9 to 15 h, measured over day and night. Although most BrC was lost within a day, possibly through chemical loss and/or evaporation, the remaining persistent fraction likely determines the background BrC levels most relevant for climate forcing
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