Novel real-time PCR assays for the specific detection of human infective Cryptosporidium species

Cryptosporidium is a protozoan parasite causing gastrointestinal illness. Drinking waterborne outbreaks have been caused by C. hominis, C. parvum and C. cuniculus. Molecular detection techniques already exist for Cryptosporidium and usually target housekeeping genes. We set ourselves the task to identify species-specific genes. These genes are likely to be involved in host parasite interaction and virulence. Three subtelomeric species-specific putative virulence factor genes (Cops-2, Chos-1 and Chos-2) were identified in silico and used to develop novel real-time PCR assays. Our results show that Chos-2 is a suitable target for probe-based assays for the specific detection of C. hominis and C. cuniculus (two very closely related species) and that Cops-2 is a suitable target for specific detection of C. parvum

High single-mode power conversion efficiency vertical-cavity top-surface-emitting lasers

Includes bibliographical references.We report advances in the power conversion (wall-plug) efficiency of vertical-cavity top-surface-emitting lasers. The devices were fabricated from molecular beam epitaxial layers using deep proton implants to define gain-guided lasers. The epitaxial structure included low resistance, piecewise linearly graded n-type and p-type mirrors, a triple In0.2Ga0.8As quantum-well active region, and a delta-doped contact layer. Power conversion efficiencies as high as 12.7% for continuous-wave single-mode operation were measured after several hours of device operation.This work was supported by the U.S. Department of Energy under Contract DE-AC04-76DP00789

Multi-locus analysis of human infective Cryptosporidium species and subtypes using ten novel genetic loci

Background: Cryptosporidium is a protozoan parasite that causes diarrheal illness in a wide range of hosts including humans. Two species, C. parvum and C. hominis are of primary public health relevance. Genome sequences of these two species are available and show only 3-5% sequence divergence. We investigated this sequence variability, which could correspond either to sequence gaps in the published genome sequences or to the presence of species-specific genes. Comparative genomic tools were used to identify putative species-specific genes and a subset of these genes was tested by PCR in a collection of Cryptosporidium clinical isolates and reference strains. Results: The majority of the putative species-specific genes examined were in fact common to C. parvum and C. hominis. PCR product sequence analysis revealed interesting SNPs, the majority of which were species-specific. These genetic loci allowed us to construct a robust and multi-locus analysis. The Neighbour-Joining phylogenetic tree constructed clearly discriminated the previously described lineages of Cryptosporidium species and subtypes. Conclusions: Most of the genes identified as being species specific during bioinformatics in Cryptosporidium sp. are in fact present in multiple species and only appear species specific because of gaps in published genome sequences. Nevertheless SNPs may offer a promising approach to studying the taxonomy of closely related species of Cryptosporidia

Investigating communicating sequential processes for Java to support ubiquitous computing

Ubiquitous Computing promises to enrich our everyday lives by enabling the environment to be enhanced via computational elements. These elements are designed to augment and support our lives, thus allowing us to perform our tasks and goals. The main facet of Ubiquitous Computing is that computational devices are embedded in the environment, and interact with users and themselves to provide novel and unique applications. Ubiquitous Computing requires an underlying architecture that helps to promote and control the dynamic properties and structures that the applications require. In this thesis, the Networking package of Communicating Sequential Processes for Java (JCSP) is examined to analyse its suitability as the underlying architecture for Ubiquitous Computing. The reason to use JCSP Networking as a case study is that one of the proposed models for Ubiquitous Computing, the ?-Calculus, has the potential to have its abstractions implemented within JCSP Networking. This thesis examines some of the underlying properties of JCSP Networking and examines them within the context of Ubiquitous Computing. There is also an examination into the possibility of implementing the mobility constructs of the ?-Calculus and similar mobility models within JCSP Networking. It has been found that some of the inherent properties of Java and JCSP Networking do cause limitations, and hence a generalisation of the architecture has been made that should provide greater suitability of the ideas behind JCSP Networking to support Ubiquitous Computing. The generalisation has resulted in the creation of a verified communication protocol that can be applied to any Communicating Process Architecture

Cryptosporidium

The protozoan Cryptosporidium is notorious for its resistance to chlorine disinfection, a mainstay of water treatment. Human infections, mainly of the small intestine, arise from consumption of faecally contaminated food or water, environmental exposure, and person-to-person or animal-to-person spread. Acute gastrointestinal symptoms can be prolonged but are usually self-limiting. Problems arise with immune-deficient, including malnourished, people including chronic diarrhoea, hepato-biliary tree and extra-gastrointestinal site infection, and few options for treatment or prevention exist. Although genomics has enabled refined classification, identification of chemotherapeutic targets and vaccine candidates, and putative factors for host adaption and pathogenesis, their confirmation has been hampered by a lack of biological tools

Expression of stress proteins during fed batch and perfusion cultures

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An Upper Ontology for Benefits Management of Cloud Computing

Benefits Management provides an established approach for decision making and value extraction for IT/IS investments and, can be used to examine cloud computing investments. The motivation for developing an upper ontology for Benefits Management is that the current Benefits Management approaches do not provide a framework for capturing and representing semantic information. There is also a need to capture benefits for cloud computing developments to provide existing and future users of cloud computing with better investment information for decision making. This paper describes the development of an upper ontology to capture greater levels of knowledge from stakeholders and IS professionals in cloud computing procurement and implementation. Complex relationships are established between cloud computing enablers, enabling changes, business changes, benefits and investment objectives