Polymerase chain reaction (PCR) is now widely used in malaria research for analysis of field samples. However, little has been reported regarding loss of sensitivity due to field methodology. Therefore, studies were carried out in relation to blood sampling (anticoagulants, culture medium, filter paper), storage (temperature, time and immediate lysis) and handling (repeated thawing and freezing). The PCR was unaffected by citrate and EDTA but partly inhibited by heparin (inhibition was reversed by heparinase at optimal concentrations). Samples collected on filter paper showed a significant 100-fold lower sensitivity (compared to control samples frozen immediately after collection) when stored at 30 degrees C and 60% humidity; and the paper quality appeared to be critical. Storage of unprocessed whole blood at 4 degrees C, 20 degrees C or 30 degrees C rarely resulted in any loss of sensitivity. Repeated thawing generally resulted in 10-fold loss of sensitivity compared to blood kept frozen until DNA extraction. The presence of antimalarial drug did not apparently affect sensitivity. We conclude that the mode of collection and storage of blood samples may influence the sensitivity of detection of malaria parasites by PCR. This may be critical in studies including individuals with low parasitaemia, mixed infections and comparison of data from different settings.
the paper is one of the few attempts to develop a Product Service System (PSS) ontology aiming to facilitate Knowledge Management in collaborative PSS design, focusing upon machine industry. The PSS ontology includes concepts such as products, services, PSS, PSS lifecycle, process and stakeholders, including direct customers, consumers and their feedback. The context sensitivity approach is proposed to fully support the use of different tools for PSS development by various stakeholders. The context model includes both PSS ontology and a so-called usercentric ontology. The process to develop the ontologies is described. The approach to build the PSS ontology is based on the so-called Basic Formal Ontology (BFO). The foreseen applications of both ontologies in industrial practice of machine vendors and the expected benefits are being elaborated.
Intelligent products, having cyber physical features, are best candidates for building Intelligent Product Service Systems (IPSS), in which integrated products and services provide a higher level of intelligence. Such IPSS may actively provide feedback on their use, which in turn may support the development of new IPSS. The objective is to develop a set of tools to establish a Collaborative Network, where both human actors and products themselves can collaborate and contribute to the development of such IPSS. The tools support involvement of various stakeholders within the Collaborative Networks. Several tools, such as a tool to select sensors and intelligent features at the products, a tool to model context under which IPSS is used, as well as tools to provide feedback on the IPSS use are defined. The paper presents as well the application of the proposed concept in machine industry.
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