Development and application of nested PCR for the detection of parvovirus B19 DNA

The development and characterisation of nested polymerase chain reaction (PCR) for the detection of human parvovirus B19 DNA is described. Two sets of oligonucleotide primers were used, one set have been described previously and a novel set were developed. The PCR reaction conditions were optimised for magnesium concentration, oligonucleotide primer concentration, extension time, reaction buffer and the serum treatment used for extraction of B19 DNA. The assay was characterised with a series of diagnostic sera validated by dot blot hybridisation for B19 DNA and by class specific capture radio-immunoassays for the detection of B19 IgM and IgG. The PCR assay was also applied to serial sera, throat swabs and peripheral mononuclear cells (PBMNC) collected during an outbreak of parvovirus B19. B19 DNA was detectable in the throat swabs and in the PBMNC fraction of whole blood. In situ hybridisation and immunolabelling were used in an attempt to determine the site of B19 DNA within the PBMNC fraction. B19 PCR was then applied to a number of clinical situations where the virus may play a role but where existing diagnostic tests are inadequate or require invasive procedures. PCR was used for the potential detection of B19 infection in immunocompromised patients in whom antibody responses are impaired and in anaemic malaria infected patients in whom hypergammaglobulinaemia may interfere with the detection of B19 specific antibodies. PCR was also used in the neonatal situation where little or no B19 IgM is produced and for the non-invasive diagnosis of fetal infection which currently requires fetal blood sampling. The PCR assay was also used to explore the role of B19 virus in patients with a variety of arthritic conditions. Finally, B19 PCR was applied to the detection of B19 DNA in clotting factor concentrates

Evolvable Smartphone-Based Point-of-Care Systems For In-Vitro Diagnostics

Recent developments in the life-science -omics disciplines, together with advances in micro and nanoscale technologies offer unprecedented opportunities to tackle some of the major healthcare challenges of our time. Lab-on-Chip technologies coupled with smart-devices in particular, constitute key enablers for the decentralization of many in-vitro medical diagnostics applications to the point-of-care, supporting the advent of a preventive and personalized medicine. Although the technical feasibility and the potential of Lab-on-Chip/smart-device systems is repeatedly demonstrated, direct-to-consumer applications remain scarce. This thesis addresses this limitation. System evolvability is a key enabler to the adoption and long-lasting success of next generation point-of-care systems by favoring the integration of new technologies, streamlining the reengineering efforts for system upgrades and limiting the risk of premature system obsolescence. Among possible implementation strategies, platform-based design stands as a particularly suitable entry point. One necessary condition, is for change-absorbing and change-enabling mechanisms to be incorporated in the platform architecture at initial design-time. Important considerations arise as to where in Lab-on-Chip/smart-device platforms can these mechanisms be integrated, and how to implement them. Our investigation revolves around the silicon-nanowire biological field effect transistor, a promising biosensing technology for the detection of biological analytes at ultra low concentrations. We discuss extensively the sensitivity and instrumentation requirements set by the technology before we present the design and implementation of an evolvable smartphone-based platform capable of interfacing lab-on-chips embedding such sensors. We elaborate on the implementation of various architectural patterns throughout the platform and present how these facilitated the evolution of the system towards one accommodating for electrochemical sensing. Model-based development was undertaken throughout the engineering process. A formal SysML system model fed our evolvability assessment process. We introduce, in particular, a model-based methodology enabling the evaluation of modular scalability: the ability of a system to scale the current value of one of its specification by successively reengineering targeted system modules. The research work presented in this thesis provides a roadmap for the development of evolvable point-of-care systems, including those targeting direct-to-consumer applications. It extends from the early identification of anticipated change, to the assessment of the ability of a system to accommodate for these changes. Our research should thus interest industrials eager not only to disrupt, but also to last in a shifting socio-technical paradigm

Pseudo-rotations of the closed annulus : variation on a theorem of J. Kwapisz

Consider a homeomorphism h of the closed annulus S^1*[0,1], isotopic to the identity, such that the rotation set of h is reduced to a single irrational number alpha (we say that h is an irrational pseudo-rotation). For every positive integer n, we prove that there exists a simple arc gamma joining one of the boundary component of the annulus to the other one, such that gamma is disjoint from its n first iterates under h. As a corollary, we obtain that the rigid rotation of angle alpha can be approximated by homeomorphisms conjugate to h. The first result stated above is an analog of a theorem of J. Kwapisz dealing with diffeomorphisms of the two-torus; we give some new, purely two-dimensional, proofs, that work both for the annulus and for the torus case

Practical placental examination for obstetricians

Placental examination can simply be performed immediately in delivery room by obstetricians in which takes only few minutes. The evaluation should be done step by step, starting from umbilical cord, membranes, and disk. Indications for placental examination are divided into maternal, fetal, and placental indications. The submitted placenta for further evaluation by pathologist can be kept in refrigerator or fixed in buffered formalin

Influence of consolidation process on voids and mechanical properties of powdered and commingled carbon/PPS laminates

Relations between autoclave consolidation process, microstructure and mechanical properties of thermoplastic composite laminates were investigated. For this purpose, two different carbon fibers/PPS semi-pregs were used for laminate manufacturing: a powdered fabric and a commingled fabric with stretch broken fibers. Laminates with [0°]6 stacking sequence were consolidated in autoclave. Several consolidation levels were established by varying process parameters which are external pressure, vacuum level and consolidation duration. Microstructural characterization was performed by using matrix digestion and CT-scanning to identify void content and morphology. Laminate mechanical properties in tensile, bending, compressive and interlaminar shear were also assessed. External pressure increase by 0.5MPa leads to void content reduction of 2.1% for powdered system and 5.4% for commingled system. The rising consolidation duration contributes slightly to void content decrease. Bending and interlaminar failure stress are the most sensitive to void level with a dependency on void size and location. Results acquired allow to identify main settings for optimized consolidation cycles which could be used for thermoplastic composite part manufacturing with complex shape