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    ABSTRACT: The ability of an aqueous extract of W. somnifera L. Dunal (Family: Solanaceae) roots to inhibit fibril formation by the amyloid-β peptide in vitro was investigated. W. somnifera is used extensively in traditional Ayurvedic medicine as a nerve tonic with reputed memory enhancing properties. Inhibition of fibrillogenesis measured by transmission electron microscopy and ThT fluorescence assay showed that an aqueous extract of W. somnifera strongly inhibited Aβ fibril formation in a concentration-dependent manner, when compared with control samples. These results suggest that the aqueous extract of W. somnifera root has an ability to inhibit the formation of mature amyloid-β fibrils in vitro, which are known to lead to amyloid plaque formation in vivo.
    Phytotherapy Research 05/2011; 26(1):113-7.
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    ABSTRACT: Seven essential oils with potential as acaricides for use against the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), were selected for study. These products (essential oils of manuka, cade, pennyroyal, thyme, garlic, clove bud and cinnamon bark) were deployed against different life stages of D. gallinae in laboratory tests at the (lethal concentration) LC(50) level for adult mites. For all essential oils tested, toxicity to D. gallinae juveniles was as high as toxicity to adults, if not higher. However, at the LC(50) level determined for adults, some oils were ineffective in preventing hatching of D. gallinae eggs. The essential oils were also tested under laboratory conditions at their LC(90) levels for D. gallinae adults on two model non-target species, the brine shrimp, Artemia salina (L.), and the mealworm beetle, Tenebrio molitor (L.). Results showed that not all essential oils were as toxic to A. salina and T. molitor as they were to D. gallinae, suggesting that it may be possible to select certain oils for development as acaricides against D. gallinae that would have minimal impact on non-target organisms. However, the level of toxicity to A. salina and T. molitor was not consistent across the selected essential oils.
    Medical and Veterinary Entomology 03/2010; 24(1):9-15.
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    ABSTRACT: The toxicity of a range of plant essential oils to the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), a serious ectoparasitic pest of laying hens throughout Europe and elsewhere, was assessed in the laboratory. Dermanyssus gallinae may cause losses in egg production, anaemia and, in extreme cases, death of hens. With changes in legislation and consumer demand, alternatives to synthetic acaricides are needed to manage this pest. Fifty plant essential oils were selected for their toxicity to arthropods reported in the literature. Twenty-four of these essential oils were found to kill > 75% of adult D. gallinae in contact toxicity tests over a 24-h period at a rate of 0.21 mg/cm(2). Subsequent testing at lower rates showed that the essential oils of cade, manuka and thyme were especially toxic to adult D. gallinae. The toxicity of the seven most acaricidal essential oils was found to be stable at different temperatures likely to be encountered in commercial poultry housing (15 degrees C, 22 degrees C and 29 degrees C), although results suggest that humidity and dust might influence the toxicity of some of the oils tested. The toxicity of clove bud essential oil to D. gallinae, for example, was increased at high humidity and dust levels compared with ambient levels. The results suggest that certain essential oils may make effective botanical pesticides for use against D. gallinae, although it is likely that issues relating to the consistency of the toxic effect of some oils will determine which oils will be most effective in practice.
    Medical and Veterinary Entomology 03/2010; 24(1):1-8.
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    ABSTRACT: A small-scale loading frame was used to apply tensile and compressive stresses to glass vinyl ester and glass polyester laminates in a cone calorimeter under a heat flux of 75kW m−2. It was found, for the first time, that stress has a small but significant effect on the fire reaction properties. Increasing tensile stress increased heat release rate and smoke production, while shortening the time-to-ignition. Compressive stress had the reverse effect. This was attributed to the fact that tensile stress promotes the formation of matrix microcracks, facilitating the evolution of flammable volatiles. This hypothesis is further supported by the observation that stress has the greatest effect on the early heat and smoke release peaks, with a lower effect on the final ‘run-out’ values. Stress rupture (time-to-failure) curves were produced for tension and compression. In tension, the behaviour was fibre dominated, with times-to-failure being roughly ten times those in compression. Compressive failure involved resin dominated local fibre kinking, initiated near to the rear face of the specimen. The failure time was determined by a significant proportion of the specimen reaching its glass transition temperature.
    12/2008: pages 137-154;
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    ABSTRACT: Reliably recognizing objects approaching on a collision course is extremely important. A synthetic vision system is proposed to tackle the problem of collision recognition in dynamic environments. The system combines the outputs of four whole-field motion-detecting neurons, each receiving inputs from a network of neurons employing asymmetric lateral inhibition to suppress their responses to one direction of motion. An evolutionary algorithm is then used to adjust the weights between the four motion-detecting neurons to tune the system to detect collisions in two test environments. To do this, a population of agents, each representing a proposed synthetic visual system, either were shown images generated by a mobile Khepera robot navigating in a simplified laboratory environment or were shown images videoed outdoors from a moving vehicle. The agents had to cope with the local environment correctly in order to survive. After 400 generations, the best agent recognized imminent collisions reliably in the familiar environment where it had evolved. However, when the environment was swapped, only the agent evolved to cope in the robotic environment still signaled collision reliably. This study suggests that whole-field direction-selective neurons, with selectivity based on asymmetric lateral inhibition, can be organized into a synthetic vision system, which can then be adapted to play an important role in collision detection in complex dynamic scenes.
    Artificial Life 02/2007; 13(2):93-122.
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    ABSTRACT: Detecting colliding objects in complex dynamic scenes is a difficult task for conventional computer vision techniques. However, visual processing mechanisms in animals such as insects may provide very simple and effective solutions for detecting colliding objects in complex dynamic scenes. In this paper, we propose a robust collision detecting system, which consists of a lobula giant movement detector (LGMD) based neural network and a translating sensitive neural network (TSNN), to recognise objects on a direct collision course in complex dynamic scenes. The LGMD based neural network is specialized for recognizing looming objects that are on a direct collision course. The TSNN, which fuses the extracted visual motion cues from several whole field direction selective neural networks, is only sensitive to translating movements in the dynamic scenes. The looming cue and translating cue revealed by the two specialized visual motion detectors are fused in the present system via a decision making mechanism. In the system, the LGMD plays a key role in detecting imminent collision; the decision from TSNN becomes useful only when a collision alarm has been issued by the LGMD network. Using driving scenarios as an example, we showed that the bio-inspired system can reliably detect imminent colliding objects in complex driving scenes.
    Computer Vision and Image Understanding. 01/2006;
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    ABSTRACT: Waste management is a strategic supply chain issue. This paper explores the definition and classification of waste from different viewpoints. A generic functional model is presented for modelling the material and flow of waste from both a physical and cumulative cost perspective. The application of the model is illustrated through a case study. The research demonstrates that improved waste management practices can simultaneously reduce disposal cost as well as generating additional value through the creation of new supply chains that reuse or recycle materials.
    International Journal of Production Economics. 01/2004;
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    ABSTRACT: The layout of manufacturing facilities has a large impact on operational effectiveness. This paper describes the use of clustering methods for identifying potential manufacturing cells. It is shown that these approaches produce inconclusive results for capital goods companies that produce complex products.The development of a Genetic Algorithm based optimisation method is described that minimises material movement for a given schedule of work. The model includes geometric information on resources and building constraints. The tool may be used for brown-field or green-field layout design problems. It has been applied using data obtained from an engineer-to-order/make-to-order capital goods company. The algorithm produces layouts that significantly reduce the total distance travelled by components in both green field and brown field situations.
    International Journal of Production Economics 01/2004;
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    ABSTRACT: This paper analyses the deregulation and restructuring of the global electricity supply industry and its impact upon fuel usage, generation technologies and suppliers of power plant. Deregulation encouraged the growth of new independent power producers whose business requirements transformed the power plant industry. The plant suppliers had to develop new capabilities and services to compete in the global market. Economies of scale and scope became crucial given the cost of developing the new technologies and providing the services required by the operators. This led to the global consolidation of the power plant industry because only large-integrated power engineering companies had the necessary resources and capabilities to compete in the new global environment.
    International Journal of Production Economics. 01/2004;
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    ABSTRACT: There are many pedagogical and resource issues associated with teaching very large groups. These relate to the delivery of course materials, student support and assessment. This paper describes the delivery and assessment of a course in Accounting and Finance studied by 310 students in the Faculty of Engineering at the University of Newcastle upon Tyne. 'Blackboard', a Web-based managed learning environment (MLE), was used to support lectures, providing access to a study guide, detailed notes and case studies. The Speedwell multiple-choice examination system was used for summative assessment.
    Engineering Science and Education Journal 11/2002;
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