7,169 research outputs found

    Improved synchronous production of Plasmodium falciparum gametocytes in vitro.

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    The sexual stages of the Plasmodium falciparum life cycle are attractive targets for vaccines and transmission blocking drugs. Difficulties in culturing and obtaining large amounts of sexual stage P. falciparum parasites, particularly early stages, have often limited research progress in this area. We present a new protocol which simplifies the process of stimulating gametocytogenesis leading to improved synchronous gametocyte production. This new method can be adapted to enrich for early stage gametocytes (I and II) with a higher degree of purity than has previously been achieved, using MACS magnetic affinity columns. The protocol described lends itself to large scale culturing and harvesting of synchronous parasites suitable for biochemical assays, northern blots, flow cytometry, microarrays and proteomic analysis

    A framework for use in modelling the modal choice decision making process in North West England’s Atlantic Gateway

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    The task of producing a generic model of the modal choice decision making process is a challenging one. Modal choice is strongly influenced by the infrastructure limitations and geographical constraints of the area in which the decision is being made. With this in mind, addressing modal choice on an individual basis for each region may be the optimal solution. This is the approach adopted in this paper. The creation of a modal choice model is a multistage process of which this paper addresses the first stage, the production a framework of the decision making process. Firstly, a number of criteria that are commonly used in modal choice models are identified. Then a number of gaps in the criteria utilized in previous papers are established. Subsequently, the method used to produce a framework of the decision making process within North West England’s Atlantic Gateway is outlined. Through consultation with transport industry experts in North West England, an initial list of sixty eight papers was reduced to thirty six that were considered to be of specific relevance to modern day freight transportation within their region. The criteria used in each of these papers were then, along with further industry input, used to create the foundation on which a modal choice framework specific to the Atlantic Gateway could be built. A greater understanding of what influences modal choice within this region will allow informed decisions to be made by policy makers on how to more efficiently utilize the available modes of freight transport. Having established this, future work can then go on to build upon these findings. This paper recommends that future work is performed to establish the weights of each criteria and sub-criteria within the framework. This should then be followed by establishing industry’s perceptions of the best and worst alternatives for moving freight within the Atlantic Gateway

    Detection of elliptical shapes via cross-entropy clustering

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    The problem of finding elliptical shapes in an image will be considered. We discuss the solution which uses cross-entropy clustering. The proposed method allows the search for ellipses with predefined sizes and position in the space. Moreover, it works well for search of ellipsoids in higher dimensions

    Modelling the Portevin-Le Chatelier effects in aluminium alloys

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    Plastic deformation processes are among the most demanding processes in manufacturing causing different microstructure feature in materials. A number of various dislocation patterns can be induced by plastic strain under different conditions. A serrated yielding/jerky flow in some dilute alloys like aluminium-magnesium alloys during plastic deformation is a well-known phenomenon under certain regimes of strain rate and temperature reported in a significant number of works. The serrated features in these materials are so-called the Portevin-Le Chatelier effects. The occurrence of these undesirable effects is due to the interaction between solute atoms and mobile dislocation during the plastic deformation which is known as dynamic strain ageing. There are a significant number of theoretical and numerical investigations that have been focused on describing the serrated behaviour of these materials during plastic deformation. Hence, the fundamental objective of this paper is a general review of different constitutive modelling in regards with this feature. The typical material models and new constitutive models describing this feature are presented. In addition, applications of the models are provided indicating their advantages and disadvantages

    Characteristics, Risk Factors, and Treatment Practices of Known Adult Hypertensive Patients in Saudi Arabia

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    Objective. To determine the prevalence, risk factors, characteristics, and treatment practices of known adult hypertensives in Saudi Arabia. Methods. Cross-sectional community-based study using the WHO stepwise approach. Saudi adults were randomly chosen from Primary Health Care Centers catchment areas. Data was collected using a questionnaire which included sociodemographic data, history of hypertension, risk factors, treatment practices, biochemical and anthropometric measurements. Collected data was cheeked, computer fed, and analysed using SPSS V17. Results. Out of 4719 subjects (99.2% response), 542 (11.5%) subjects were known hypertensives or detected by health workers in the past 12 months. Hypertension was significantly associated with age, gender, geographical location, education, employment, diabetes, physical inactivity, excess body weight, and ever smoking. Multiple logistic analysis controlling for age showed that significant predictors of hypertension were diabetes mellitus, ever smoking, obesity, and hypercholesteremia. Several treatment modalities and practices were significantly associated with gender, age, education, and occupation. About 74% were under prescribed treatment by physicians, 62% on dietary modification, 37% attempted weight reduction, 27% performed physical exercise, and less than 7% used herbs, consulted traditional healers or quitted smoking. Income was not significantly associated with any treatment modality or patient practices. Conclusion. Hypertension (known and undetected) is a major chronic health problem among adults in Saudi Arabia. Many patients' practices need changes. A comprehensive approach is needed to prevent, early detect, and control the disease targeting, the risk factors, and predictors identified
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