published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

An increase in the range and capability of imaging modalities has resulted in greater demands for radiology services. This research investigates how these changes have affected role requirements and role extensions of radiographers and the consequent implications for the educational needs of radiographers. Semi-structured interviews and three successive surveys of NHS radiography managers showed that the adoption and diffusion of extended roles in radiography had increased significantly over a ten year period. Role changes included additions both to the procedures carried out by radiographers, and to the reporting of procedures, e.g. film reporting, once the domain of radiologists, is now undertaken by radiographers in many trusts. Imaging managers’ views on the factors that encouraged or deterred the introduction of extended roles were explored. While many radiographers were keen to adopt new roles, implementation was unlikely without radiological support. Respondents believed the proposed ‘four-tier structure’ would help overcome staffing difficulties, while providing an improved career framework to advance the professional status of radiographers. A key theme was the need for greater clinical knowledge to facilitate transition to advanced practice. Three studies investigated radiography education. The first used a survey to investigate the preparedness for practice of three cohorts of newly qualified radiographers. Graduates recognised the importance of continuing professional development with extended role skills identified as a priority. The second study examined the relationship between contemporary practice and UK undergraduate radiography curricula. Most programmes had responded positively to developing technology. The third study used a survey to investigate the training for extended roles provided by employers. While most provided some training, much was unaccredited, and there was considerable variation in the duration of training for similar roles. The research has documented developments taking place at a time of enormous technological innovation. It provides key data on the changing practice of radiography that will be useful to all stakeholders planning improvements to radiography services. The data lead to a re-definition of practice and recommendations for supporting education and training.

L'accroissement des performances énergétiques de systèmes industriels motorisés mettant en œuvre des machines électriques à courants alternatifs fait actuellement l'objet d'enjeux majeurs. Les travaux présentés dans ce mémoire s'inscrivent dans ce contexte et concernent la conception d'un outil (cellule) de diagnostic énergétique. Le verrou majeur à lever consiste à estimer le couple électromagnétique des machines AC, sans décapoter leurs boîtes à bornes ni mesurer leurs vitesses de rotation. La thèse a permis de développer des techniques non invasives, basées sur la mesure du courant de ligne et/ou du flux de dispersion dans l'environnement proche de la machine. Des analyses fines de la distribution du flux de dispersion autour de la carcasse ont été réalisées car le flux est atténué et déphasé sous l'influence des courants de Foucault. L'analyse a également permis de distinguer la contribution des conducteurs actifs de celle des têtes de bobines dans la génération du flux externe. Une image du flux d'entrefer a donc pu être mise en évidence, ainsi que la manière de la mesurer, conduisant à la définition de protocoles de détermination du couple. Ces derniers sont complétés par une méthode reposant sur la mesure ou l'estimation à partir du flux de dispersion du courant de phase. Les méthodes dégagées ont été appliquées à des machines asynchrones dont les puissances s'échelonnent de 3 à 200 kW. La conception de la cellule s'est étendue à son architecture et, notamment, à la transmission sans fil des informations collectées. La gestion de l'autonomie a été un critère prépondérant durant toute l'étude, conduisant d'une part à l'élaboration d'algorithmes légers donc peu énergivores pour la cellule et, d'autre part, à l'introduction du flux de dispersion comme source d'énergie alternative. / The energetic performance increase of industrial processes using AC electrical rotating machines is nowadays of great concern. The developments presented in this thesis are situated in this context and are about the design of an energy monitoring tool (cell). The main scientific barrier to lift is the estimation of the electromagnetic torque of AC machines without dismounting their terminal box or measuring their shaft speed. Non invasive methods have been developed; they are based on the measurement of the phase current and/or the external flux in the immediate vicinity of the machine. Analyses of the external flux distribution around the external housing were made : the magnetic flux is attenuated and phase shifted because of the eddy current effect. Then, the analysis has made it possible to distinguish the contribution of the wires placed in the slots from the effect of the end-windings in the external flux emission. The work explains how to determine an image of the external flux, as well as the way to measure it. That leads to the definition of protocols for determining the electromagnetic torque, which, for some of them use current measurements or its estimation from the external flux. The proposed methods have been applied to induction machines with rated powers between 3 to 200 kW. The cell structure is described, in particular the wireless transmission of the measured information. The autonomy of the cell is a factor taken into account troughout the study, leading to the development of little-intensive computing algorithms. It is also shown that the external flux can be used as an additional energy source.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Melinda J. Wilkerson / Tick-borne bacteria, Ehrlichia canis, Anaplasma platys, and Ehrlichia chaffeensis are significant zoonotic pathogens of dogs and humans worldwide. In tropical regions such as Grenada, West Indies, dogs represent a major reservoir for E. canis and A. platys, and they are often co-infected. The purpose of this study was to develop a serologic, multiplex bead-based assay to detect species-specific exposures to E. canis, A. platys, and E. chaffeensis in dogs for purposes of surveillance and public health. Peptides from specific outer membrane proteins of P30 for E. canis, OMP1X of A. platys, and P28-19/P28-14 of E. chaffeensis were coupled to magnetic beads and assays were optimized using the multiplex Luminex xMAP® platform. In experimentally infected dogs, the multiplex assay successfully detected antibodies for E. canis and E. chaffeensis, but not A. platys. In the Grenadian population (n=104), the multiplex assay and the in-house ELISA, the SNAP® 4Dx®, detected A. platys antibodies as well as Ehrlichia spp.. Multiplex assay results were found to have “good” and “very good” agreement with the ELISA and IFA for E. canis antibody-positive dogs (K value of 0.73 and 0.84 respectively), while ELISA and IFA had “very good” agreement with each other (K value of 0.85). A. platys multiplex results had only “poor” agreement with ELISA and IFA (K value of -0.02 and 0.01, respectively), while the ELISA and IFA tests had “moderate” agreement with each other (K value of 0.5). These tests showed the prevalence of exposure to E. canis to be comparable with previous studies (38% in 2014), but a doubling of exposure to A. platys determined by IFA and 4Dx® from 9% in 2006, to 20% in 2014. Bayesian modeling (performed on E. canis data only) suggested conditional independence between the IFA, 4Dx®, and MAG tests using consensus priors calculated from literature, and that the bead-assay had comparable sensitivity and specificity to the IFA and ELISA tests. In conclusion, the multiplex peptide assay performed well in detecting the seropositive status of dogs to E. canis and had good agreement with commercial assays; however, more work needs to be done to assess performance in populations of dogs with exposures to multiple species of Ehrlichia. Further, the reasons for low seroreactivity to A. platys need to be further investigated.

M.A.

Ebola viruses cause sever disease in humans and non-human primates. The resulting disease, Ebola virus disease (EVD), can have hemorrhagic manifestations and has mortality rates ranging from 20-90%. There is a strong need for better understanding of the disease as well as improved diagnostics and prognostics. One approach to improving diagnostic and prognostics for severe viral diseases such as EVD is to define how the host response to infection develops and produces indicators of disease and outcome. To create a better means to understand if a patient is likely to survive or succumb to Ebola (EBOV) infection, I have sought to develop an understanding of the host response to EBOV infection in humans from the recent outbreak. I analyzed RNA-Seq samples from the 2013-2016 West Africa outbreak. I identified that the innate immune pathways are in general over activated in EVD and is stronger in patients who succumbed to disease. Furthermore, I developed a set of 10 genes that can perform as a prognostic indicator of disease independent of the viral load. This is the first demonstration that the circulating transcriptional immune response to EBOV infection can be used to predict infection outcome. To work towards a diagnostic platform of disease, I analyzed multiple studies of time-resolved datasets in animal models of disease. I analyzed RNA-Seq and NanoString data coupled with telemetry data in EBOV-challenged macaques. The earliest and strongest changes seen in the pre-symptomatic stage of disease is the up-regulation of many innate immune genes. I used this information to develop a NanoString codeset that can act as a pre-symptomatic indicator of disease that was tested in further animal studies as a diagnostic in pre-symptomatic stages of disease. Together, this work has identified a sets of genes that can work as a diagnostic for pre-symptomatic patients of EBOV and act as a prognostic indicators of disease. In future outbreaks, this type of information will be important to help track primary contacts of infected individuals and first responders, as well as better inform clinical management of patients. This lays the groundwork for similar analysis to be performed on other severe viral diseases such as Lassa Fever and Marburg Fever. / 2019-11-27T00:00:00Z

Rotavírus têm sido identificados mundialmente como o mais importante agente etiológico de diarréias agudas não-bacterianas em animais jovens de várias espécies, incluindo a humana. Foi desenvolvido e avaliado um método de ELISA tipo “duplo-sanduíche" para a detecção de rotavírus a partir de material fecal. Para tanto, a amostra NCDV de rotavírus do grupo A foi propagada em cultivo celular com células MA-104. O vírus foi concentrado por ultracentrifugação e inoculado em coelhos e carneiros. Em seguida, as frações IgG, oriundas de amostras de soro dos animais, foram purificadas por cromatografia de troca iônica e absorvidas com soro total de ambas espécies animais, utilizando-se polímero de glutaraldeído, de modo a eliminar reações inespecíficas. A presença do rotavírus foi detectada pela IgG de carneiros e revelada pela IgG de coelho, usando como conjugado IgG de cabra anti-IgG de coelho conjugada à peroxidase. Os valores de diluição dos componentes do ELISA e o valor do ponto-de-corte foram definidos usando-se 26 amostras fecais (13 positivas e 13 negativas) de leitões, tendo como prova padrão a eletroforese em gel de poliacrilamida (PAGE). Aplicado a um painel constituído de 86 amostras fecais diarréicas de leitões, os resultados do ELISA foram: 100% de sensibilidade; 98,79% de especificidade, com uma concordância de 98,83%. A variância entre 86 repetições da mesma amostra foram 0,001 (para a amostra positiva) e 0,0002 (para a amostra negativa). Estes resultados demonstram que este ELISA é um teste sensível e específico para o diagnóstico de rotavírus a partir de material fecal. / Rotaviruses have been identified worldwide as a major etiologic agent of acute nonbacterial diarrhea in the young of many species, including humans. In this investigation was developed and evaluated a “double-sandwich" antibody ELISA method for detection of rotavirus from stool specimens. For that, the NCDV strain of rotavirus group A was serially cultivated in MA-104 cell culture. The virus was concentrated by ultra-centrifugation and inoculated in rabbits and sheeps. After that, the IgG of serum samples of the animals was purified by ion-exchange chromatography and absorbed with whole serum of both animal species using a glutaraldehyde polymer, in order to eliminate inespecific reactions. The presence of rotavirus was detected by the sheep’s IgG and revelated by the rabbit’s IgG, using a anti-rabbit IgG peroxidase conjugate developed in goat. The values of diluition of the components of the ELISA and the cut-off value were defined using 26 fecal samples (13 positive and 13 negative) of piglets. Following this procedure, the test was employed in a panel of 86 fecal samples from piglets with diarrhea, using as standard the polyacrilamide gel electrophoresis (PAGE) test. The results of the ELISA were: 100% of sensivity; 98.79% of specificity, with an agreement of 98.83%. The variance between 86 repetitions of the same sample were 0.001 (for one positive sample) and 0.0002 (for one negative sample). These results showed that this ELISA is an sensitive and specific screening test for rotavirus diagnosis from fecal material.

Muitas ferramentas de diagnóstico da dengue tornaram-se disponíveis, porém requerem coleta de sangue como amostra para análise. Um método não invasivo de confirmar a infecção por dengue seria de importância considerável para os estudos clínicos e epidemiológicos. Testes de saliva podem encorajar os pacientes a serem mais receptivos para o diagnóstico da dengue. Possíveis problemas com o uso de sangue incluem a exigência de consentimento e a cooperação do paciente. Em muitos casos, flebotomia em indivíduos com fobia de agulhas, portadores de deficiências e discrasias sanguíneas e, especialmente em bebês e crianças, ou ainda devido a razões sociais, religiosas, à necessidade de um enfermeiro treinado e à necessidade de se separar o soro do plasma antes do teste. Objetivo deste trabalho foi identificar RNA viral em amostras de saliva de pacientes infectados com dengue durante o período febril; avaliar o teste rápido para identificar NS1 em amostra de saliva; identificar a presença de NS1 em amostras de saliva por meio do teste ELISA. Foram coletas amostras de saliva de pacientes durante o período febril com e sem dengue. Todos diagnósticos foram confirmados por exame de sangue para IgM/IgG. Foi feito o teste da Reação em Cadeia da Polimerase em Tempo Real em 10 amostras de pacientes com dengue. Em 44 amostras foram testados as tiras de diagnóstico rápido da dengue e ao teste ELISA NS1, para a detecção da proteína NS1. Esse estudo ressaltou a importância da busca pelo diagnóstico laboratorial rápido, prático e financeiramente acessível de doenças febris agudas com sintomas inespecíficos, principalmente em áreas de ocorrência de dengue. Nesse estudo foi encontrada alta especificidade (94%) e média sensibilidade (73%) nos resultados da identificação da proteína NS1 nas amostras de saliva em estágios precoces da infecção por dengue. Esse método, se aprimorado para saliva, poderá ter resultados ainda melhores, por isso mais estudos são necessários. / This study brings a literature review about the current dengue status worldwide and in Brazil followed by a systematic review that highlights the dengue diagnosis through saliva. A prospective study was also made, which evaluated the dengue virus infection diagnosis accuracy through the NS1 antigen detection in saliva samples using ELISA assays. The NS1-ELISA results in saliva were compared to the IgM-ELISA and IgG-ELISA serology. A total of 44 saliva samples were obtained from November 2012 to February 2013. The results showed that de NS1-ELISA presented a sensibility of 0.73, specificity of 0.94, Positive Predictive Value of 0.95, Negative Predictive Value of 0.70, Positive Likelihood Ratio of 13.15, Negative Likelihood Ratio of 0.28. Having these findings in mind, it is possible to suggest that the NS1 detection in saliva may be an important diagnostic tool in special cases, such as people that fear needles, with blood dyscrasias, babies, children, as well as to quickly monitor epidemics and their dissemination.

Hui, Lai Shan. / Thesis (M.Sc.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 83-87.

by Ye Jian. / Abstract in English and Chinese. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves [140-147]). / ABSTRACT --- p.i / ACKNOWLEDGEMENTS --- p.v / LIST OF ABBREVIATIONS --- p.vi / TABLE OF CONTENTS / Chapter CHAPTER 1 --- Introduction / Chapter 1.1 --- What is the EBI technique --- p.1-1 / Chapter 1.2 --- Applications of the EBI technique --- p.1-2 / Chapter 1.3 --- The electrical impedance rheopneumography-an overview --- p.1-4 / Chapter 1.4 --- Goal of the work --- p.1-6 / Chapter 1.5 --- Main contributions of the work --- p.1-9 / Chapter 1.6 --- Organization of the thesis --- p.1-9 / Chapter CHAPTER 2 --- Principles of the EBI technique and physiological background of the rheopneumogram / Chapter 2.1 --- Tissue impedance and origins of impedance change --- p.2-1 / Chapter 2.1.1 --- Impedance of living organs --- p.2-1 / Chapter 2.1.2 --- Origins of impedance change --- p.2-2 / Chapter 2.2 --- The data acquisition system (DAS) --- p.2-3 / Chapter 2.2.1 --- Impedance detector --- p.2-3 / Chapter 2.2.2 --- Constant current source and safety consideration --- p.2-4 / Chapter 2.2.3 --- Computer interface --- p.2-5 / Chapter 2.3 --- Electrode systems --- p.2-6 / Chapter 2.3.1 --- Two-/four-electrode systems --- p.2-6 / Chapter 2.3.2 --- Geselowitz lead field theory --- p.2-6 / Chapter 2.3.3 --- Comparisons between the two-/four-electrode systems --- p.2-7 / Chapter 2.4 --- The human cardiovascular system --- p.2-8 / Chapter 2.4.1 --- System operation --- p.2-8 / Chapter 2.4.2 --- Pulmonary hemodynamics --- p.2-9 / Chapter 2.5 --- Physiological background of EIR waveform --- p.2-12 / Chapter 2.6 --- EIR wave morphology and pathological factors --- p.2-13 / Chapter 2.6.1 --- Variations in the a-wave --- p.2-13 / Chapter 2.6.2 --- Variations in the Z-wave --- p.2-14 / Chapter 2.6.3 --- Variations in the C-wave --- p.2-14 / Chapter CHAPTER 3 --- THE COMPOSITION OF IMPEDANCE SIGNAL / Chapter 3.1 --- Introduction --- p.3-1 / Chapter 3.1.1 --- Origins of the TIS --- p.3-1 / Chapter 3.1.2 --- EIR measurement and electrode position --- p.3-2 / Chapter 3.1.3 --- Optimal EIR measurement --- p.3-3 / Chapter 3.2 --- Current path in an inhomogeneous medium --- p.3-4 / Chapter 3.3 --- Numerical model --- p.3-5 / Chapter 3.3.1 --- 2D Model --- p.3-5 / Chapter 3.3.2 --- Tissue resistivity --- p.3-6 / Chapter 3.4 --- Calculation of the potential distribution --- p.3-7 / Chapter 3.5 --- Results --- p.3-9 / Chapter 3.5.1 --- Computer simulations --- p.3-9 / Chapter 3.5.2 --- Experimental results --- p.3-13 / Chapter 3.6 --- Discussions --- p.3-14 / Chapter 3.7 --- Conclusion --- p.3-16 / Chapter 3.8 --- Note on publications --- p.3-17 / Chapter CHAPTER 4 --- ON-LINE RESPIRATORY ARTEFACT REMOVAL VIA ADAPTIVE TECHNIQUE / Chapter 4.1 --- Introduction --- p.4-1 / Chapter 4.2 --- Analysis of the TIS --- p.4-3 / Chapter 4.3 --- Modified adaptive noise canceller --- p.4-7 / Chapter 4.3.1 --- Principle of the ANC method --- p.4-8 / Chapter 4.3.2 --- LMS algorithm --- p.4-8 / Chapter 4.3.3 --- MANC method --- p.4-9 / Chapter 4.3.4 --- Results --- p.4-10 / Chapter 4.4 --- Adaptive moving averager --- p.4-15 / Chapter 4.4.1 --- Modified moving averager --- p.4-15 / Chapter 4.4.2 --- Respiratory artefact elimination with adaptive MMA --- p.4-16 / Chapter 4.4.3 --- Performance of the adaptive MMA filter --- p.4-16 / Chapter 4.4.4 --- Results --- p.4-18 / Chapter 4.5 --- Adaptive FIR filter Design --- p.4-22 / Chapter 4.5.1 --- Introduction --- p.4-22 / Chapter 4.5.2 --- Adaptive FIR filter --- p.4-23 / Chapter 4.5.3 --- Results and discussions --- p.4-24 / Chapter 4.6 --- Simultaneously monitoring respiratory and pulmonary circulation- An application of TIS --- p.4-30 / Chapter 4.7 --- Comparisons of the proposed filter schemes --- p.4-33 / Chapter 4.7.1 --- Performance of the filters --- p.4-33 / Chapter 4.7.2 --- Computational complexity and reduced schemes --- p.4-34 / Chapter 4.8 --- Conclusions --- p.4-37 / Chapter 4.9 --- Notes on publications --- p.4-37 / Chapter CHAPTER 5 --- MODELING ANALYSIS OF THE RHEOPNEUMOGRAM / Chapter 5.1 --- Introduction --- p.5-1 / Chapter 5.2 --- Pulmonary circulation modeling --- p.5-2 / Chapter 5.3 --- Model deduction --- p.5-4 / Chapter 5.3.1 --- Pressure-flow in arteries and veins --- p.5-4 / Chapter 5.3.2 --- The two-chamber model and the EIR model --- p.5-5 / Chapter 5.4 --- Parameter estimation --- p.5-8 / Chapter 5.4.1 --- The fitting function and the parameter equations --- p.5-8 / Chapter 5.4.2 --- Curve fitting --- p.5-10 / Chapter 5.4.3 --- Solution of the parameter equations --- p.5-11 / Chapter 5.5 --- Study of the model parameter sensitivity --- p.5-12 / Chapter 5.6 --- Results --- p.5-13 / Chapter 5.7 --- Conclusion --- p.5-17 / Chapter 5.8 --- Notes on publications --- p.5-17 / Chapter CHAPTER 6 --- ANIMAL EXPERIMENTS AND CLINICAL OBSERVATIONS / Chapter 6.1 --- Introduction --- p.6-1 / Chapter 6.2 --- Animal experiments --- p.6-2 / Chapter 6.2.1 --- Methods --- p.6-2 / Chapter 6.2.2 --- Occlusion of the right pulmonary arterial blood flow --- p.6-3 / Chapter 6.2.3 --- Reflection waves in rheopneumogram --- p.6-4 / Chapter 6.3 --- Clinical observations --- p.6-4 / Chapter 6.3.1 --- Mitral valve stenosis --- p.6-5 / Chapter 6.3.2 --- Obstructive emphysema --- p.6-7 / Chapter 6.4 --- Conclusion remarks --- p.6-8 / Chapter 6.5 --- Notes on publications --- p.6-9 / Chapter CHAPTER 7 --- RECAPITULATION AND TOPICS FOR FUTURE INVESTIGATION / Chapter 7.1 --- Recapitulation --- p.7-1 / Chapter 7.2 --- Conclusions --- p.7-3 / Chapter 7.3 --- Topics for future investigation --- p.7-4 / Chapter 7.4 --- Applications of the EIR technique --- p.7-5 / REFERENCES / APPENDICES / Chapter A. --- A circuit diagram of the four-electrode system --- p.A-l / Chapter B. --- NISA/EMAG (A SOFTWARE PACKAGE OF FEM) --- p.A-2 / Chapter C. --- LMS algorithm --- p.A-3 / Chapter D. --- Curve fitting --- p.A-5 / Chapter E. --- List of publications --- p.A-8