Dissertations / Theses on the topic 'Diagnostic agent'
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Rokka, Johan. "Agent-Based Argumentative Diagnostic Reasoning in Dementia." Thesis, Umeå universitet, Institutionen för datavetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-52092.
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This thesis describes the development of a source-based argumentation dialogue system in the medical domain of dementia. Its aim is to enable a physician and a computer agent to establish the presence or absence of a dementia condition or diagnoses for a specific patient. The participants take turn in making the moves in a dialogue, every move consists of an argument or a critical question (a challenge) and during the process of arguments and counterarguments an argumentation-tree, in which a winner may be declared, is constructed.The following four particular problems are formulated and solved: 1. how could an appropriate argumentation graph be designed enabling a dementia debate; 2. how could an algorithm automatically select attacks in the argumentation graph on behalf of the computer agent using ACKTUS, a semantic web-application for modeling knowledge (1); 3a. how could the reasoning in an argumentation graph be improved by using inquiry dialogues introduced by Black & Hunter (2) to ensure a correct winner election; 3b how could it handle the mutual attack problem, and 4. how could the solutions for these issues be implemented?Through a literature study, ACKTUS review, discussions with expertise and a trial and error approach, solutions to the above problems were suggested. The design of schemes, critical questions and their relation was constructed following a source-based approach. An attack algorithm using a ranking- and a selection procedure was invented where the selection was based on likelihood of winning, degree of user-friendliness, profit, essentiality in the discussion and user preferences. A defeasible logic adapted by Black & Hunter was introduced for the arguments in the designed argumentation graph. After applying special techniques, Black & Hunter’s inquiry dialogue system were used to create dynamic arguments in a new argumentation tree, which enabled a comparison with the designed argumentation tree. This ensured the correctness of the winner election in that argumentation tree. Also an ignorance concept, where the latest attack always is considered a winner, was used to deal with the mutual attack problem. A web-based implementation of the system was accomplished.The results were evaluated regarding functionality. However, a presentation of the system to physicians with further evaluation, still remains. Limitations of the system are that it uses a subset of ACKTUS content that does not include the handling of conflicting arguments, and the mutual attack problem is limited. These issues are all subjects for further development and improvement. Another future prospect is an introduction of Artificial Intelligence algorithm/s such as CBR (Case Base Reasoning) which might improve the system’s performance.One conclusion was that even more refinements were needed before using the system in health care. Another conclusion was that the work had shown how a system for dementia could be developed using an argumentation dialogue between a computer agent and a human participant with an algorithm for automatically attacks and an improvement of reasoning ensuring the accuracy of the winner election.
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Haigh, Julian Saunders. "Investigation in to the Effect of Spin Locking on Contrast Agent Relaxivity." PDXScholar, 2015. http://pdxscholar.library.pdx.edu/open_access_etds/2496.
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The current trend in magnetic resonance imaging (MRI) is towards higher external magnetic field strengths (B0) to take advantage of increased sensitivity and signal to noise ratio (SNR). Unfortunately, as (B0) increases the effectiveness (relaxivity) of clinical gadolinium (Gd3+)-based contrast agents (CAs) administered to enhance image contrast is significantly reduced. Excellent soft tissue contrast can be generated with current agents despite their non-optimum relaxivities but necessitates large doses. The limits of detection of a CA at high B0 fields can be lowered by recovering the lost relaxivity and is a pre-requisite to the goal of molecular imaging in which CAs are bound to biomarkers of pathology that exist at very low concentrations. Traditional methods for increasing the detectability of CAs have focused on optimizing critical parameters identified from the Solomon-Bloembergen-Morgan (SBM) theory that affect relaxivity. Gains in relaxivity with these methods to date have been modest and are far from the theoretical maximum possible. Although researchers continue to investigate novel complexes that provide improved relaxivities, any such complex would require a lengthy and costly approval process with the U.S. Food and Drug Administration (FDA). Therefore, a method that affords improved relaxivities of current clinically approved CAs, particularly at high B0 fields, that could be adopted into clinical practice rapidly, is of great interest.
Spin locking is a nuclear magnetic resonance (NMR) technique that was introduced for imaging in 1985, but has received very little attention in combination with Gd3+-based CAs. The technique employs a low power long duration radiofrequency (RF) pulse (B1) parallel to the net magnetization in the x,y-plane. This locks the magnetization into lower precessional frequencies around an "effective" field (Beff) that is reduced with respect to B0 but maintains the high field advantages required for imaging. When considered in the rotating frame, longitudinal relaxation of the magnetization against Beff exhibits shorter time constants (T1p) expected at these lower precessional frequencies. This leads to higher relaxivities, which has implications for increasing CA detectability.
The experiments described herein show that rotating frame longitudinal relaxivities (r1p) for current clinical Gd3+-based CAs are essentially independent of the strength of the spin lock pulse (yB1) as predicted by theory. This result is important because it allows the value of yB1 to be neglected when comparing r1p of Gd3+-based CAs across several B0 fields. The magnetic field dependence of r1p for all clinical agents showed that relaxivity, lost by moving to higher fields, could be "recovered" and that r1p was sensitive to the rotational correlation time constant (TR) of the agent. Using high molecular weight Nanoassembled capsules (NACs) containing a Gd3+-based CA to probe this finding further, we were able to generate relaxivities at high field up to an order of magnitude greater than clinical agents at current imaging fields. These are beyond anything previously reported, or likely to be, with current techniques. Finally, we demonstrated that by spin locking Mn2+ agents, relaxivities at high field increased by a factor of ~ 30 than without spin locking, due to their larger dependence on scalar coupling. These findings show the potential of spin locking to increase detection limits dramatically at high field and are an exciting development towards the goal of molecular imaging.
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Kandanapitiye, Murthi S. "Synthesis of Biocompatible Nanoparticulate Coordination Polymers for Diagnostic and Therapeutic Applications." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1429019837.
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Dumont, Julien. "Systèmes multi-agent pour le diagnostic pluri-disciplinaire." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2011. http://tel.archives-ouvertes.fr/tel-00844133.
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Ce travail de recherche est consacré à la formalisation et à la réalisation d'un processus de diagnostic pluridisplinaire. La particularité d'un tel diagnostic résulte du fait qu'il nécessite de nombreux spécialistes, chacun ayant des connaissances sur leur domaine. Le problème principal réside dans les interconnexions entre les domaines. Ces interconnexions peuvent ou non être connues et influer sur le diagnostic. Dans ce manuscrit, nous proposons de réaliser un diagnostic pluridisciplinaire l'aide d'un système multi-agents. Les agents élaborent un diagnostic local à un domaine puis, fusionnent leurs diagnostics afin d'obtenir le diagnostic pluridisciplinaire. Dans ce but, nous proposons un cadre d'argumentation et une méthode de fusion des diagnostics. Ensemble, ces deux propositions forment le modèle ANDi.
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COSTA, ANDREW DINIZ DA. "A HYBRID DIAGNOSTIC-RECOMMENDATION APPROACH FOR MULTI-AGENT SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=13383@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSistemas multi-agentes são sociedades com agentes autônomos e heterogêneos que podem trabalhar em conjunto para alcançar objetivos similares ou totalmente diferentes. Quando falhas acontecem enquanto algum agente de software tenta alcançar seus objetivos, torna-se importante entender porque tais falhas acontecem e o que pode ser feito para remediar tais problemas. Considerando o ambiente distribuído, dinâmico e a natureza dos sistemas multi-agentes, é importante definir os requisitos necessários para realizar diagnósticos das falhas e recomendações de planos alternativos para agentes que desejam alcançar seus objetivos. Assim, esta dissertação propõe soluções para os principais desafios de criar um sistema que realize diagnósticos e proveja recomendações sobre execuções de agentes. Além disso, o trabalho propõe um framework híbrido de diagnóstico e recomendação que provê suporte para tais desafios. A partir do framework, instâncias de diferentes domínios podem ser criadas, como, por exemplo, aplicações baseadas em computação ubíqua e diferentes diagnósticos e recomendações podem ser providas.
Multi-agent systems are societies with autonomous and heterogeneous agents that can work together to achieve similar or different goals. Agents executing in such systems may not be able to achieve their goals due to failures during system execution. When an agent tries to achieve its desired goals, but faces failures during execution, it becomes important to understand why such failures occurred and what can be done to remedy the problem. The distributed, dynamic and nature of multi-agent systems calls for a new form of failure handling approach to address its unique requirements, which involves both diagnosing specific failures and recommending alternative plans for successful agent execution and goal attainment. We discuss solutions to the main challenges of creating a system that can perform diagnoses and provide recommendations about agent executions to support goal attainment, and propose a hybrid diagnostic-recommendation framework that provides support for methods to address such challenges. From the framework, instances of different domains can be created, such as, applications based on ubiquitous computing and different diagnoses and recommendations can be provided.
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Touaf, Samir. "Diagnostic logique des systèmes complexes dynamiques dans un contexte multi-agent." Université Joseph Fourier (Grenoble), 2005. http://www.theses.fr/2005GRE10038.
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Cette thèse propose une méthodologie pour la conception de systèmes de diagnostic fiables permettant d'appréhender les systèmes dynamiques complexes et spatialement distribués. Les résultats proposés s'appuient d'une part sur des techniques d'analyse diagnostic formelle ou à base de consistance, qui permettent de garantir la justesse de l'analyse diagnostic, et d'autre part, sur le paradigme multiagents. Les algorithmes proposés permettent de déduire tous les défauts possibles pour un comportement observé en les classant suivant différents critères de vraisemblance. Notre contribution a consisté à proposer une méthode de diagnostic qui tire partie des deux approches DX (communauté d'Intelligence Artificielle) et FOI (communauté Automatique) en distinguant la phase de détection, qui peut se faire à base de techniques variées et parfois très sophistiquées (observateur d'état, relation de parité, traitement de signal,. . . ), de la phase de localisation ou d'analyse diagnostic, qui doit permettre de garantir ce qui peut l'être et d'analyser toutes les informations disponibles pour en déduire le diagnostic le plus juste et complet possible. De plus, nous avons montré qu'il était possible d'appréhender des incertitudes de décision en transposant la logique de l'analyse diagnostic en logique floue. Le travail présenté dans ce mémoire a été développé dans le cadre du projet européen MAGIC (Multi-Agents-Based Diagnostic Data Acquisition and Management in Complex systems). Les résultats sont en cours de transfert vers différentes industries grâce aux partenaires industriels du projet : les entreprises SATE (System Advanced Technologies Engineering) et SMS-DEMAGThis thesis proposes a methodology to design a reliable diagnosis systems permitting to comprehend the dynamic complex and spatially distributed systems. The proposed results lean on the, one hand, techniques of formai analysis diagnosis or to basis of consistency, that permits to guarantee the exactness of the diagnosis analysis, and on the other hand, on multi-agents paradigm. The proposed algorithms permit to deduct ail possible faults for an observed behavior while classifying them according to different criteria of plausibility. Our contribution consisted in proposing a method of diagnosis that pulls left of the two DX approaches (Artificial intelligence community) and FOI (Control community) while distinguishing the phase of detection, that can be done by various and sometimes very sophisticated techniques (state observer, parity relation, signal based,. . . ), of the phase of localization or diagnostic analysis, that must permit to guarantee what can be, and to analyze ail available information to deduct the just diagnosis and possible suit of i1. Besides, we showed that it was possible to fear uncertainties of decision while transposing the logic of the analysis diagnosis in fuzzy logic. Work presented in this memory has been developed in the setting of the European project called MAGIC (Multi-Agents-Based Diagnostic Data Acquisition and Management in Complex systems). Results are under transfer toward different industries thanks to the industrial partners of the project : the SATE enterprises (System Advanced Technologies Engineering) and SMS-DEMAG
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Hughes-Riley, Theodore. "Development and application of hyperpolarized krypton-83 as a new MRI contrast agent." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14460/.
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Hyperpolarized (hp) gases such 129Xe and 83Kr (spin I = 1/2 and I = 9/2 respectively) can allow for significantly enhanced signal in a number of magnetic resonance applications. As a result there has been a growing interest in recent years to advance hp noble gas technology to non-invasively image the airspace of lungs, with the goal of developing a helpful probe for lung pathologies. 83Kr longitudinal relaxation (T1) has been shown to be sensitive to various surface properties, and may prove to be an interesting for identifying certain diseases including those that change surface chemistry (such as cystic fibrosis) or the surface-to-volume ratio in the lung (like in emphysema). This thesis contains several studies furthering 83Kr lung imaging, while also exploring methods for 129Xe imaging. A major focus has been on increasing spin polarization of the noble gases, as an increased polarization yields a greater MR signal strength. A novel low-pressure spin-exchange optical pumping technique has been utilized in this work allowing for 83Kr polarizations exceeding 17.5 %; as opposed to 4.4 % previously reported in literature. Gas produced in this fashion must be pressurized to above ambient before it is possible for it to be delivered to a lung. Two methodologies for pressurizing the noble gas via compression are explored and optimized for hp gas delivery to excised lungs with 83Kr polarizations as high as 13.8 % achievable after compression. This ultimately allowed for the first ever coronal 83Kr lung images in an ex vivo lung model. Further work repeated with isotopically enriched 83Kr achieved a surface-sensitive T1 relaxation map in this system. Finally gas handling techniques where created to allow for efficient and thorough mixing of the hp noble gases and O2 while minimizing relaxation effects. This is vital for any future in vivo studies.
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Kumar, Akhauri Prakash. "Agent based diagnostic system for the defect analysis during chemical mechanical polishing (CMP)." Heimsheim Jost-Jetter, 2005. http://deposit.d-nb.de/cgi-bin/dokserv?idn=976561247.
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Bryson, Joshua Matthew. "The Design and Study of Lanthanide-Chelating Macromolecular Diagnostic and Delivery Agents." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28726.
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Macromolecular magnetic resonance imaging (MRI) contrast agents have unique localization and contrast enhancement properties. We have designed and studied a monodisperse paramagnetic β-cyclodextrin click cluster (Gd10) decorated with Gd-containing arms and unique contrast enhancing polymers. To synthesize Gd10, a novel alkyne-functionalized diethylenetriaminetetraacetic acid chelate was created and coupled to a per-azido-β-cyclodextrin core and chelated with Gd(III) to yield the precursor macromolecule. Luminescence measurements were carried out using an analogous structure Eu(III)-containing structure and indicated that each lanthanide has an average of 1.8 water exchange sites. Gd10 yields a high relaxivity profile (6.2 mM⁻¹ s⁻¹ per Gd(III) at 9.4 T). Gd10 shows toxicity higher than clinically used contrast agents such as Magnevist&trade in vitro in cardiomyoblast cells. No acute toxicity was observed in the rats (n = 9) and contrast enhanced image analysis indicates renal processes may be involved in clearance.
The contrast enhancing polymers we developed are new macromolecular beacons that allow the delivery of nucleic acids to be visualized at different biological scales. They contain repeated oligoethyleneamines, for binding and compacting nucleic acids into nanoparticles, and Gd(III)/Eu(III) chelates. The chelated lanthanides allow the visualization of the delivery vehicle via microscopy and via magnetic resonance imaging (MRI). We demonstrate that these new delivery beacons effectively bind plasmid DNA(pDNA) and protect their cargo nucleic acids from nuclease damage. The lanthanide-chelate materials have been found to efficiently deliver pDNA into cultured cells and do not exhibit toxicity. Micrographs of cultured cells exposed to the nanoparticle complexes formed with fluorescein-labeled pDNA and the europium-chelated polymers reveal effective intracellular imaging of the delivery process. MRI of bulk cells exposed to the complexes formulated with pDNA and the gadolinium-chelated structures show bright image contrast, allowing visualization of effective intracellular delivery on the tissue-scale. Because of their versatility as imaging probes, these delivery beacons posses remarkable potential for tracking and understanding nucleic acid transfer in vitro and have promise for in vivo imaging applications. In later studies the Ln-chelating polymers were co-polymerized with dimethylgalacterate which definitively increases luciferase gene expression (up 50x enhancement) and cellular uptake (up to 2x enhancement).Ph. D.
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Travagin, Fabio. "Synthesis of new contrast agents for biomedical applications." Doctoral thesis, Università del Piemonte Orientale, 2021. http://hdl.handle.net/11579/127849.
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Several different metal complexes are currently used in diagnostics and therapy (MRI, PET, SPECT, OI, TAT etc.). For their preparation a chelating agent (CA) is mandatory to hold the metal ion, to reduce its toxicity and to target its activity. Polyaminocarboxylates and polyaminophosphonates represent the best choice of CAs for the preparation of metal complexes exploited as imaging probes. These scaffolds ensure high thermodynamic and kinetic stability of the corresponding metal complex. However, their preparation is not always straightforward.
During this PhD the research work was focused on the following three main objectives:
1) A strategy for the 1,7-heterodiprotection of cyclen with orthogonal protecting groups have been realised. This protection method is based on the control of pH to implant two different and orthogonal protecting groups in the cyclen scaffold.
2) This protection method has been exploited to prepare two novel bifunctional chelating agents (BFCAs) bearing a phosphonic functionality (DO2AP(tBu)4 and DO3AP(tBu)4). These two novel BFCAs have been designed to prepare innovative and stable metal complexes conjugated with vectors such as antibodies, peptides, nucleotides etc.
3) Three innovative CAs have been prepared and characterised:
- TRASUTA is a hexadentate mesocyclic chelating agent and a rigidified AAZTA-like ligand for the coordination of Ga(III).
- Cb-tebpm is a cyclam-based chelating agent, designed to prepare stable complexes with gadolinium or in general with lanthanides.
- HB-DO3A is an HP-DO3A homologue, optimised to be a strong Gd(III) chelator. HBDO3A has been investigated in its safety profile. In vitro data have shown that, if compared to clinically approved MRI CAs, HB-DO3A presents low affinity to collagen. This characteristic could confer HB-DO3A the advantage of a faster and complete clearance after administration to the patient, with less release of toxic Gd(III) and less side effects.
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Papachristou, Maria, George Kastis, Petros Stavrou, Stavros Xanthopoulos, Lars Furenlid, Ioannis Datseris, and Penelope Bouziotis. "Radiolabeled methotrexate as a diagnostic agent of inflammatory target sites: A proof-of-concept study." SPANDIDOS PUBL LTD, 2017. http://hdl.handle.net/10150/626570.
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Methotrexate (MTX), as a pharmaceutical, is frequently used in tumor chemotherapy and is also a part of the established treatment of a number of autoimmune inflammatory disorders. Radiolabeled MTX has been studied as a tumor-diagnostic agent in a number of published studies. In the present study, the potential use of technetium-99m-labelled MTX (Tc-99m-MTX) as a radiotracer was investigated for the identification of inflammatory target sites. The labelling of MTX was carried out via a Tc-99m-gluconate precursor. Evaluation studies included in vitro stability, plasma protein binding assessment, partition-coefficient estimation, in vivo scintigraphic imaging and ex vivo animal experiments in an animal inflammation model. MTX was successfully labelled with Tc-99m, with a radiochemical purity of >95%. Stability was assessed in plasma, where it remained intact up to 85% at 4 h post-incubation, while protein binding of the radiotracer was observed to be similar to 50% at 4 h. These preclinical ex vivo and in vivo studies indicated that Tc-99m-MTX accumulates in inflamed tissue, as well as in the spinal cord, joints and bones; all areas with relatively high remodeling activity. The results are promising, and set the stage for further work on the development and application of Tc-99m-MTX as a radiotracer for inflammation associated with rheumatoid arthritis.
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Haverick, Mark Anthony. "Self-Assembling Peptide Amphiphile Contrast Agents as a Tumor Diagnostic Tool." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316184031.
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Martina, Marie Sophie. "Conception de magnétoliposomes furtifs pour le diagnostic et la thérapie anti-cancéreuse." Paris 11, 2006. http://www.theses.fr/2006PA114831.
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Un nouveau système hybride résultant de l'encapsulation de nanoparticules d'oxyde de fer superparamagnétiques dans des vésicules phospholipidiques stabilisées stériquement par des chaînes de poly(éthylène glycol) (PEG) a été mis au point et caractérisé. Ces magnétoliposomes, stables et biocompatibles sont d'excellents agents de contraste pour l'imagerie par résonance magnétique (IRM) qui, par application d'un gradient de champ magnétique externe, peuvent être guidés in vivo dans le tissu tumoral ou un hémisphère cérébral. In vitro, la présence de chaînes de PEG réduit fortement l'association magnétoliposome/macrophages (lignée J774) sans pour autant modifier la cinétique d'endocytose des magnétoliposomes une fois ceux-ci liés à la surface des cellules. Dans le cas de cellules d'adénocarcinome prostatique humain, il a été montré que l'internalisation cellulaire des magnétoliposomes pouvait être nettement favorisée en présence d'un gradient de champ magnétiqueA novel hybrid nanosystem, resulting from the encapsulation of iron oxid nanoparticles into stercally stabilised phospholipidic vesicles, has been realised and characterised. These socalled magnetoliposomes, revealed as excellent MRI contrast agents, could be guided towards a tumor tissue or a cerebral hemisphere thanks to an external magnetic gradient
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YARABARLA, SRIRAMAKRISHNA. "Synthesis and Application of Polymer Stabilized, Water Dispersible Copper Based Nanoparticles as Anti-cancer and Diagnostic Agents." Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1492608832326.
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Nguyen, Thi Thanh Quynh. "Diagnostic distribué et commande tolérante aux défauts pour les systèmes multi-agents." Thesis, Reims, 2020. http://www.theses.fr/2020REIMS006.
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Un système multi-agents (MAS) peut-être défini par un groupe d'agents qui communiquent entre eux. Au cours de la dernière décennie, les MAS se sont révélés être une solution efficace et économique à de nombreux problèmes d'ingénierie complexes, difficiles voire impossibles à résoudre par un seul agent.Malgré l’abondance de résultats dans la littérature concernant sur le contrôle coopératif des MAS, il y a encore des points d’amélioration, en particulier en termes de fiabilité et de performance de fonctionnement du contrôle coopératif en cas de panne. Cette thèse vise une contribuer à la résolution des problèmes de diagnostic de défaut distribué et de FTC pour les MAS non homogènes/hétérogènes à topologies commutées. Dans un premier temps, une approche basée sur un observateur de détection de défaut distribué (FD) pour un réseau d'agents non homogènes ayant des topologies de commutation est proposé. Nous avons commencé par la formalisation d'un modèle virtuel correspondant à chaque agent. Ce modèle prend en compte toutes les informations locales disponibles pour l'agent, à savoir le modèle virtuel, ainsi que la fonction de commutation de topologie. Cette représentation se présente sous la forme d'un système commuté impulsif continu. Par la suite, nous présentons une approche basée sur l'IMT pour concevoir un filtre FD distribué. Dans cette approche proposée, nous utilisons des indices H_ /Hinf pour garantir la sensibilité du résidu aux défauts ainsi que sa robustesse à la perturbation. Nous utilisons également plusieurs fonctions de Lyapunov qui satisfont à la contrainte de commutation lente pour assurer la convergence des observateurs synthétisés.Par la suite, notre étude porte sur l’estimation distribuée des défauts (FE) pour un réseau d'agents non homogènes avec des défauts actionneurs et des topologies de commutation. Dans ce travail, nous continuons à utiliser le modèle virtuel commuté résultant de nos travaux sur FD pour représenter le modèle de chaque agent. Nous proposons une nouvelle méthode de décomposition qui permet de décomposer l'état de l'agent et de ses voisins en deux sous-états, l'un est affecté par les défauts actionneur et l'autre n'est pas affecté par les défauts. Un observateur distribué pour chaque agent est également proposé pour estimer les sous-ensembles d'état. Enfin, les estimations de défaut sont obtenues en utilisant simultanément l'estimation d'état et un différenciateur exact robuste. Il convient de noter que cette approche proposée est distribuée à la fois dans la conception et la mise en œuvre. En effet, elle n'a pas besoin des informations de l'ensemble des systèmes et elle permet également à chaque agent d'estimer ses défauts et ceux de ses voisins. Par conséquent, nous pouvons ainsi réduire les temps de calcul et de communication lors d’une mise en œuvre dans des applications pratiques.Enfin, le développement de FE et FTC pour un réseau d'agents hétérogènes soumis à des défauts actionneurs et à un consensus de sortie est abordé. L'objectif est d'améliorer par FTC la fiabilité et les performances lors d’un fonctionnement coopératif des MAS hétérogènes avec présence de défauts. Cette approche est basée sur des modèles de référence internes et un observateur d'estimation des défauts. Les agents s'appuient sur les informations fournies par les modules FE et ne nécessitent aucune connaissance a priori sur le défaut. Un FE décentralisé basé sur l'observateur est synthétisé pour estimer les états et les défauts de l'actionneur. La conception des observateurs est donnée après des décompositions d'état en utilisant des matrices de transformation. Ensuite, un contrôleur à consensus tolérant aux défauts est proposé. Il utilise l'état estimé et les défauts estimés résultant de l'observateur d'estimation des défauts. L’accord entre les agents est obtenu en résolvant le problème du consensus des références internesA multi-agent system (MAS) can be defined by a group of agents that communicate with each other. Over the past decade, MAS have proven to be an effective and economical solution to many complex engineering problems that are difficult or even impossible to solve by a single agent.Despite the abundance of results in the literature on cooperative control of SAM, there are still areas for improvement, in particular in terms of reliability and operational performance of cooperative control in the event of a failure. This thesis aims to contribute to the resolution of the problems of distributed fault diagnosis and FTC for non-homogeneous / heterogeneous MAS with switched topologies. First, an approach based on a distributed fault detection (FD) observer for a network of non-homogeneous agents with switching topologies is proposed. We started with the formalization of a virtual model corresponding to each agent. This model takes into account all the local information available to the agent, namely the virtual model, as well as the topology switching function. This representation is presented in the form of a switched continuous impulsive system. Next, we present an IMT-based approach to design a distributed FD filter. In this proposed approach, we use H_ / Hinf indices to guarantee the sensitivity of the residue to defects as well as its robustness to disturbance. We also use several Lyapunov functions which satisfy the slow switching constraint to ensure the convergence of the synthesized observers.Subsequently, our study focuses on distributed fault estimation (FE) for a network of non-homogeneous agents with actuator faults and switching topologies. In this work, we continue to use the switched virtual model resulting from our work on FD to represent the model of each agent. We propose a new method of decomposition which makes it possible to decompose the state of the agent and its neighbors in two sub-states, one is affected by the actuator faults and the other is not affected by the faults. A distributed observer for each agent is also proposed to estimate the state subsets. Finally, default estimates are obtained by simultaneously using state estimation and a robust exact differentiator. It should be noted that this proposed approach is distributed both in design and implementation. Indeed, it does not need information from all the systems and it also allows each agent to estimate its faults and those of its neighbors. As a result, we can reduce computation and communication times when implemented in practical applications.Finally, the development of FE and FTC for a network of heterogeneous agents subject to actuator faults and an exit consensus is discussed. The objective is to improve reliability and performance by FTC during cooperative operation of heterogeneous MAS with the presence of faults. This approach is based on internal reference models and an observer for estimating faults. The agents rely on the information provided by the FE modules and do not require any prior knowledge of the fault. A decentralized FE based on the observer is synthesized to estimate the states and faults of the actuator. The design of the observers is given after state decompositions using transformation matrices. Next, a fault-tolerant consensus controller is proposed. It uses the estimated state and the estimated faults resulting from the defect estimation observer. The agreement between the agents is obtained by solving the problem of consensus of internal references
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Radkowitsch, Anika [Verfasser], and Frank [Akademischer Betreuer] Fischer. "Facilitating collaborative diagnostic reasoning : effects of collaboration scripts in agent-based medical simulations / Anika Radkowitsch ; Betreuer: Frank Fischer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1234912015/34.
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Webber, Benjamin Charles. "Investigation of the Structure and Dynamics of Regioisomeric Eu³⁺ and Gd³⁺ Chelates of NB-DOTMA: Implications for MRI Contrast Agent Design." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1498.
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The detection of disease and abnormal pathology by magnetic resonance imaging (MRI) has been aided significantly by the use of gadolinium (Gd3+)-based contrast agents (CAs) over the past three decades. MRI and MRI CAs play a critical role in diagnosing tumors and diseases of the central nervous system. The agents used clinically have been shown to safely increase MRI contrast despite the toxicity of Gd3+, owing to the high kinetic and thermodynamic stability of these chelates. However, current CAs enhance contrast at a small fraction of what is theoretically possible. This leads to the necessity of introducing high CA doses in practice in order to afford sufficient contrast. Lanthanide (Ln3+) chelates based on 1,4,7,10–tetraazacyclododecane–1,4,7,10–tetraacetate (DOTA) have been shown to be particularly stable and effective. Chelates of DOTA exist in two interconverting coordination geometries which have varying water exchange rates. Researchers have envisioned a way to increase the per-dose efficacy both by control of the Gd3+–inner–sphere water exchange rate and via binding specificity (i.e. to tumors). The efficacy gains using these approaches have thus far been modest.
A thorough structural characterization of europium (Eu3+) chelates of a DOTA-derivative which cannot undergo conformational exchange was carried out. These studies show that a single enantiomer of the ligand (S)–2–(4-nitrobenzyl)–1,4,7,10–tetraazacyclododecane–1,4,7,10–tetra(α–methyl)acetate (NB–DOTMA) can yield chelates which are both diastereoisomeric (previously reported) and regioisomeric (not previously speculated). Molecular mechanics simulations generated from the characterization data indicate that the nitrobenzyl (NB) substituent is oriented in different directions for the two possible regioisomers. The NB group can be chemically converted to confer macromolecular binding capability, and the orientation of the NB substituent may have a significant impact on the binding and/or relaxation behavior of a prototypical CA.
The nuclear magnetic resonance (NMR) spectra of Eu–NB–DOTMA at various temperatures were compared. Unexpectedly, the chelates showed time-averaged structures which differ with a change in water exchange rate — the faster the rate, the greater the deviation from the expected structure. Consideration of the structures of Ln3+ chelates without accounting for their dynamic behavior does not yield an accurate value for the time-averaged hydration state. These observations suggest the "optimal" water exchange rate calculated using Solomon-Bloembergen-Morgan (SBM) theory may not lead to the highest-efficacy CAs. Binding and relaxometric studies of macromolecule-targeting derivatives of Gd–NB–DOTMA both by the author and in another lab showed that the coordination isomer with the slower water exchange rate should lead to more effective contrast, in direct opposition to the prevailing view of water exchange in the MRI community. Preliminary data do not indicate that regioisomeric chelates have significantly different relaxivity or macromolecular binding behavior.
The ratios between regioisomeric Ln–NB–DOTMA chelates formed were shown to be dependent on the concentration and pH of the chelation reaction, but conditions were not found which led to the production of a single regioisomer. Attempts to carry out an efficient synthesis of a Ln3+ chelate with no potential for regioisomerism were unsuccessful.
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Bosco, Lionel. "Développement de sondes radicalaires intelligentes pour le diagnostic par IRM réhaussée par l'effet Overhauser." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4756/document.
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Ce travail expose deux stratégies pour le développement de nouveaux agents de contraste pour le diagnostic par IRM rehaussée par l’effet Overhauser.Le premier thème de ce travail est consacré au développement d’une sonde radicalaire, de type nitroxyde, capable de modifier sa signature RPE (Résonance Paramagnétique Electronique) en fonction d’une activité enzymatique. Cette modification, due à un changement conformationnel, a permis une irradiation microonde sélective de la sonde libérée par protéolyse. Cette particularité a pu être appliquée à l’IRM rehaussée par l’effet Overhauser et une amélioration du contraste de l’image de 1200% in vitro a été observée après hydrolyse enzymatique. Du fait de contraintes techniques, une amélioration du contraste de 600% a été obtenue in vivo alors que de nos jours,les agents de contraste les plus courants en clinique, basés sur des complexes de GdIII, améliorent le contraste de l’image d’environ 50 %. Le second thème aborde la synthèse et l’étude physico-chimique d’alcoxyamines, précurseurs de nitroxydes, pour le diagnostic par IRM rehaussée par l’effet Overhauser. Le point clé de cette approche repose sur l’activation de ces molécules afin de libérer rapidement le nitroxyde in situ. Les résultats de monoactivation chimique étant encourageants, la double activation chimique de ces nouvelles alcoxyamines a permis d’abaisser drastiquement le temps de demi-vie de l’une d’entre elles pour obtenir des valeurs compatibles avec des applications en diagnostic. Un pseudo-peptide sélectif de la chymotrypsine a également été greffé,ce qui a permis d’aboutir à une alcoxyamine modèle qui permettra de valider le concept de diagnostic recherchéThis work promotes two strategies for the development of new contrast agents for the diagnosis by Overhauser enhanced MRI. Two approaches have therefore been addressed.The first approach is devoted to the development of a nitroxide-type spin label, which is capable to change its EPR (Electron Paramagnetic Resonance) signature upon a non-radical enzymatic activity. This modification, due to a conformational change, allowed us to perform a selective microwave irradiation of the probe released by proteolysis. This feature was applied to Overhauser enhanced MRI and of the image after enzymatic hydrolysis of 1200% in vitro has been obtained. Due to technical hindrances, a contrast enhancement of 600% has been obtained in vivo, while nowadays, the most common clinical contrast agent, based on GdIII complex, improve image contrast around a value of 50%.The second topic deals with the synthesies and the physico-chemical study of alkoxyamines, as nitroxide precursors, for the diagnosis by MRI enhanced by the Overhauser effect. The key point of this approach is based on the activation of these molecules to quickly release the nitroxide in situ. Encouraged by the results of chemical monoactivation, we performed the double chemical activation of these new alkoxyamines to drastically reduce the half-life time of one of them to obtain values compatible with diagnostic applications. A selective pseudo-peptide of chymotrypsin has also been grafted, which allowed us to achieve an alkoxyamine model that will validate our concept of diagnosis
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SANCHEZ, VERONIQUE. "Synthese, emulsification et evaluation in vivo de composes fluores radioopaques pour leur emploi comme agent de contraste en diagnostic medical." Nice, 1993. http://www.theses.fr/1993NICE4670.
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Les developpements des fluorocarbures en diagnostic ont etabli leur interet comme agent de contraste lorsqu'ils sont rendus radioopaques par la presence d'atome lourd, tel le brome dans le bromure de perfluorooctyle (pfob). Cependant, l'effet de contraste du a ce seul atome de brome est modere, compare a celui de l'iode des opacifiants radiologiques actuels. Une etude realisee sur divers fluorocarbures ethyleniques iodes, dibromes et tribromes a permis de selectionner les 1,2-bis(f-alkyl)iodoethenes, r#f#ci=chr#f(fnnie), et les 1-alkyl-2-(f-alkyl)iodoethenes, r#fch=cir#h(fnhmie), comme agents de contraste potentiels car ils concilient une radioopacite in vitro 4 fois superieure a celle du pfob et une biocompatibilite elevee (45-50 g/kg). Disperses en presence de lecithines de jaune d'uf (eyp), les fnnie donnent des emulsions concentrees a 90% p/v, a la fois fines et de distribution resserree, et resistantes a la sterilisation thermique (121c, 15 min). Ces emulsions sont stables au vieillissement (a 40c pendant 3 mois); toutefois une diminution du ph lors de la sterilisation limite leur developpement in vivo. Les fluorocarbures mixtes fnhmie, etudies en melange avec le pfob intensifient le contraste des emulsions en fonction des quantites incorporees. De plus, introduits avec un rapport molaire 1/1 avec eyp, les produits fnhmie stabilisent les emulsions de pfob et de f44ie. Par ailleurs, les emulsions de f6h6ie seul, preparees avec eyp (77/4 ou 33/6% p/v) sont stables au vieillissement et leur sterilisation ne modifie pas leur ph. Leur tolerance par injection intraveineuse de 8 g/kg en f6h6ie s'accompagne d'une persistance intravasculaire correcte (t#1#/#2=6 heures) et d'une excretion rapide t#1#/#2(foie)=6 jours. Enfin, leur radioopacite in vivo est elevee et necessite 5 a 7 fois moins de f6h6ie pour creer un contraste identique a celui du pfob
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Perng, John Kangchun. "Ultrasound imaging of oxidative stress in vivo with chemically generated gas microbubbles." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43608.
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Ultrasound contrast agents (UCA) have tremendous potential for in vivo molecular imaging because of their high sensitivity and great spatial resolution of ultrasound imaging. However, the diagnostic potential of UCAs has been difficult to exploit because current contrast agents are based on pre-formed microbubbles, which can only detect cell surface receptors. In this work, we demonstrated that chemical reactions that generate gas forming molecules can be used to perform molecular imaging by ultrasound in vivo. This new approach for generating ultrasound contrast agents was demonstrated by imaging reactive oxygen species (ROS) in vivo with allylhydrazine, a compound that is converted into nitrogen and propylene gas after reacting with radical oxidants. We demonstrated that allylhydrazine encapsulated within liposomes (termed APLs) can detect a 10 uM concentration of radical oxidants by ultrasound, and can image oxidative stress in mice, induced by lipopolysaccharide (LPS), using a clinical ultrasound machine. We showed that a 1-2% increase in gas concentration above saturation can be detected acoustically and suggest that numerous biological targets can be imaged via appropriately designed gas forming reactions. This work was the first demonstration of in vivo imaging of ROS using ultrasound, and this work presented a new strategy to generate gas bubbles from reactions involving radical oxidants. We anticipate numerous applications of chemically generated microbubbles, given the excellent spatial resolution of ultrasound imaging, its widespread clinical use and its high sensitivity to detect gas bubbles.
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Kumar, Akhauri Prakash [Verfasser]. "Agent based diagnostic system for the defect analysis during chemical mechanical polishing (CMP) / Universität Stuttgart, IFF, Institut für Industrielle Fertigung und Fabrikbetrieb ... Akhauri Prakash Kumar." Heimsheim : Jost-Jetter, 2005. http://d-nb.info/976561247/34.
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Hingot, Vincent. "Development of ultrasound localization microscopy to measure cerebral perfusion during stroke : a study in mouse models prior to its translation in humans." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS562.
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L’échographie est une technique d’imagerie médicale employant des ultrasons. Un examen classique se base sur deux modes principaux, le mode B pour l’imagerie anatomique et le mode Doppler pour l’imagerie des flux sanguins.Dans le contexte des maladies cérébro-vasculaires, l’échographie sert principalement à estimer les altérations du flux sanguin dans les artères cérébrales majeures au travers du Doppler transcranien. Cependant, la faible qualité des images à travers le crâne ne permet pas à l’échographie d’être aussi performante que l’imagerie par résonance magnétique.Les récents progrès en échographie ont permis l’émergence de nouveaux modes d’imagerie, en particulier une technique de super-résolution ultrasonore qui permet d’augmenter la résolution ainsi que le contraste de l’imagerie vasculaire. Elle se base sur l’imagerie rapide de microbulles couramment utilisées comme agents de contraste pour l’échographie. En utilisant cette méthode, il a été possible d’imager jusqu’aux plus petits vaisseaux et permettrait chez l’homme l’imagerie de la perfusion cérébrale de manière plus performante que le Doppler transcranien. Cela pourrait rendre possible une prise en charge plus précoce et plus efficace des patients victimes d’accidents vasculaires cérébraux. Avant d’être utilisée dans un contexte médical, la technique de super-résolution ultrasonore doit être mieux comprise, mieux réalisée, et adaptée au contexte particulier des accidents vasculaires cérébraux. En particulier, ce manuscrit discutera des meilleures méthodes de formation d’image, et se penchera sur les performances réelles de l’imagerie super résolue. Nous discuterons également des possibilités de corriger les artefacts dus aux mouvements physiologiques et des possibilités d’utiliser l’imagerie super résolue dans divers organes et en particulier les reins, les tumeurs et la moelle épinière. L’étude approfondie par imagerie super résolue de modèles d’ischémie cérébrale chez le rongeur permettra de construire des biomarqueurs vasculaires adaptés au diagnostic des pathologies cérébro-vasculaires et devrait aider la translation vers des patients humainsUltrasonography is a medical imaging technique that uses ultrasound. A typical examination is based on two main modes, B-mode for anatomical imaging and Doppler mode for blood flowimaging. In the context of cerebrovascular diseases, ultrasonography is used primarily to estimate alterations in blood flow in major cerebral arteries through transcranial Doppler. However, the low quality of the images through the skull does not allow ultrasound to be as efficient as magnetic resonance imaging. Recent advances in ultrasound have led to the emergence of new modes of imaging, particularly a super-resolution ultrasound technique that increases the resolution and contrast of vascular imaging. It is based on the rapid imaging of microbubbles commonly used as contrast agents for ultrasound. This method has shown that it can image even the smallest vessels and allows to perform cerebral perfusion imaging more effectively than Transcranial Doppler. This would allow earlier and more effective management of stroke patients. Before being used in a medical context, this ultrasound super-resolution technique must be better understood, better realized, and adapted to the particular context of cerebrovascular diseases. In particular, this manuscript will discuss how to best form images, and will look at the actual performance of super-resolved imaging. We will also discuss the possibilities of correcting artefacts due to physiological movements and the possibilities of using super-resolved imaging in various organs, particularly the kidneys, tumors and spinal cord. Finally, imaging of models of cerebral ischemia in rodents will enable the construction of vascular biomarkers suitable for the diagnosis of cerebrovascular pathologies and should aid translation into human patients
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Douaiher, Marie-Noëlle. "Pathogénicité de Mycosphaerella graminicola, agent de la septoriose du blé : rôle des enzymes de dégradation des parois cellulaires." Littoral, 2006. http://www.theses.fr/2006DUNK0136.
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Afin d'étudier la production des activités enzymatiques de dégradation des parois cellulaires de blé in vitro par Mycosphaerella graminicola, deux souches de référence (323 et 94269) ont été cultivées sur le milieu synthétique S dans lequel le galactose et/ou les parois cellulaires constituent les sources de carbone. Les cinétiques de production ont montré des niveaux d'activités différents entre les deux souches et selon les sources de carbone utilisées. Cinq des sept activités recherchées ont été produites en quantités significatives : xylanase, β-xylosidase, polygalacturonase, cellulase et β-1,3-glucanase. L'analyse en composantes principales (ACP) a permis de mettre en évidence deux groupes d'activités enzymatiques. Le premier comprend les activités cellulase et polygalacturonase et le second les activités xylanase, β-xylosidase et β-1,3-glucanase. L'ACP a également montré que le milieu S complété par le galactose et les parois cellulaires est le milieu optimal qui permet la production du plus large éventail d'enzymes de dégradation de parois cellulaires du blé. Nous avons ensuite étudié la pathogénicité des deux souches de référence et de six autres souches de M. Graminicola. Celle-ci a été mesurée par différents paramètres correspondant à l'expression du symptôme et la production des pycnides sur des feuilles de blé maintenues en survie. La détermination des activités enzymatiques in vitro des huit souches montre des quantités significatives de xylanase, β-xylosidase, cellulase, β-1,3-glucanase et polygalacturonase. Enfin, les tests de corrélation et l'ACP ont montré des corrélations entre les composantes du pouvoir pathogène relatives à l'expression des symptômes, à la production des pycnides et les enzymes à activité xylanasique et pectique produites in vitro par M. Graminicola. Ces deux groupes d'enzymes sont donc a priori des éléments clés déterminants de la pathogénicité de cet agent infectieux du bléTwo Mycosphaerella graminicola isolates, 323 and 94269, have been shown to produce in vitro a range of cell wall-degrading enzymes that can potentially degrade wheat cell walls. The influence of three carbon sources on the enzymes production was studied : a) 1% galactose (w/v), b) 1% wheat cell walls (w/v) and c) a mixture of 1% galactose (w/v) and 1% wheat cell walls (w/v). The activity levels varied with the type of carbon source used. Time-course experiments showed that different levels of enzyme activities were obtained with isolates 323 and 94269. Five major activities produced by both isolates were detected : xylanase, β-xylosidase, polygalacturonase, cellulase and β-1,3-glucanase. The principal component analysis (PCA) showed them gathered into two groups significantly different. The first group concerned cellulase and polygalacturonase activities and the second one xylanase, β-xylosidase and β-1,3-glucanase activities. The PCA also showed that the optimal medium that permitted the production of most of the major activities contains both galactose and wheat cell walls. In order to investigated correlations between pathogenicity and the in vitro production of cell wall degrading enzymes, six other M. Graminicola isolates were also studied. Pathogenicity was assayed in terms of both lesions and pycnidia productions on wheat leaves. Additionally, the isolates were compared over times for their ability to produce significant levels of cell wall degrading enzymes while grown in the optimal liquid medium. Xylanase, β-xylosidase, β-1,3-glucanase, cellulase and polygalacturonase activities were again significantly produced. Correlation tests and PCA reveal a significant correlation between some of the pathogenicity components of the isolates and their in vitro production of xylanasic and pectic enzymes. We propose that these two groups of cell wall degrading enzymes are therefore good candidates for key pathogenicity determinants in M. Graminicola
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Tarrieu, Frédérique. "Analyse de la diversité phylogénétique de "Trypanosoma cruzi cruzi", agent de la maladie de Chagas, par séquençage des gènes 18S et Tc52. Applications au diagnostic moléculaire." Montpellier 2, 2000. http://www.theses.fr/2000MON20220.
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La diversite genetique de trypanosoma cruzi cruzi, un protozoaire parasite responsable de la maladie de chagas en amerique latine, est considerable. Les populations naturelles de ce parasite presentent une structure clonale caracterisee par la propagation de lignees uniparentales stables sur de grandes aires geographiques et dans le temps. Les analyses menees sur la bases de marqueurs multilocus (isoenzymes et rapd) ont mis en evidence l'existence de deux lignees majeures, les dtus (discrete typing units) 1 et 2. La dtu 2 est subdivisee en cinq dtus 2a a 2e. Dans notre etude, nous avons analyse chez 49 souches la sequence d'un domaine variable du gene 18s et chez 16 souches la sequence du gene codant pour la proteine tc52 impliquee dans les mecanismes physiopathologiques de l'infection. L'analyse phylogenetique a corrobore l'existence des deux lignees majeures. Par contre, elle individualise au sein de la dtu 2 trois subdivisions et non cinq dtus. L'analyse des sequences nucleotidiques a confirme le statut d'hybride des dtus 2d et 2e et de parents putatifs des dtus 2b et 2c et chaque dtu ou groupes de dtus sont caracterises par des caracteres specifiques. Deux applications ont ainsi pu etre developpees : la mise au point de pcr specifiques de dtu, permettant de developper une nouvelle methode moleculaire adaptee au diagnostic, au depistage de masse et en epidemiologie et l'analyse du polymorphisme de sequence du gene tc52. L'etude de ce polymorphisme a pour objectif de determiner les mutations de la proteine susceptibles de moduler ses activites.
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Benchetrit, Michael. "Identification de levures en milieu hospitalier : comparaison de 4 galeries à lecture colorimétrique." Paris 5, 1997. http://www.theses.fr/1997PA05P041.
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Lucain, Pierrre-Eric. "IRM-ferumoxides versus portoscanner dans la détection des métastases hépatiques." Montpellier 1, 1996. http://www.theses.fr/1996MON11016.
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Dupas, Benoît. "Detection des metastases hepatiques et caracterisation de la necrose cellulaire aigue en irm : action des agents de contraste ; nanoparticules d'oxyde de fer, dysprosium et gadolinium." Angers, 1996. http://www.theses.fr/1996ANGE0505.
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Platteau, Jean-Marc. "L'agent de maitrise face à l'informatique. Enquête-diagnostic a Renault-Flins. : L'évaluation sociologique : une exigence majeure pour l'entreprise en quête de competitivite." Lille 1, 1988. http://www.theses.fr/1988LIL12011.
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L'informatique, un facteur d'efficacité pour les organisations? Assurément. . . . Mais encore faut-il qu'elle ne subisse pas de la part des utilisateurs les affres de "l'effet placard", car tel est bien le risque majeur qui guette ses promoteurs lorsqu'ils ne s'interrogent pas suffisamment sur les conditions propres à favoriser une insertion sociale réussie. La démarche choisie valorise-t-elle une dynamique de l'autonomie et de l'apprentissage? Alors, il devient possible de donner au projet initial les dimensions d'un véritable projet sociotechnique. S'appuie-t-elle sur une exploration approfondie des logiques stratégiques et culturelles des acteurs intéressés? On dispose alors des atouts nécessaires pour faire du temps de l'innovation un temps privilégié de "développement social". Fruit d'une enquête menée, plusieurs mois durant, a renault-flins auprès d'une population d'agents de maitrise concernée par un projet d'informatisation, la présente étude s'inscrit dans cette double orientation. Si elle cherche, bien sûr, à répondre aux préoccupations initiales des promoteurs du nouvel outil, elle se veut aussi, au-delà, une ébauche de réflexion à propos du "changement en organisation", du rôle de l'analyste social d'entreprise et de la politique de gestion des ressources humainesAre computers a factor of efficiency in organizations? By all means. . . . At least if they do not suffer from their users the "cupboard effect", for there is the basic danger for their promoters when the proper conditions leading to a successful social insertion have not been correctly dealt with. Is the proceeding setting off a dynamic of autonomy and training? Then the initial project may have the dimensions of a real sociotechnical project. Is it based on a thorough survey of the concerned actors strategical and cultural logics? Then all the necessary assets are gathered in order to make of the time of innovation a time of social development. Fruit of a several months investigation in renault-flins with a population of foremen interested in a project towards computerization, this study follows this twofold direction. If it intends to answer the initial worries of the new tool's promoters, it also means to try and meditate upon "the change in organization", the socieal analyst's role and the policy of the manpower management
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Zurkiya, Omar. "Magnetic Resonance Molecular Imaging Using Iron Oxide Nanoparticles." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/19848.
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Magnetic resonance imaging (MRI) is regularly used to obtain anatomical images, greatly advancing biomedical research and clinical health care today, but its full potential in providing functional, physiological, and molecular information is only beginning to emerge. The goal of magnetic resonance molecular imaging is to utilize MRI to acquire information on the molecular level. This dissertation is focused on ways to increase the use of MRI for molecular imaging using superparamagnetic iron oxide (SPIO) nanoparticle induced MRI contrast. This work is divided into three main sections: 1) Elucidation of the contribution of size and coating properties to magnetic nanoparticle induced proton relaxation. To maximize contrast generated without increasing particle size, new methods to increase effects on relaxivity must be developed. Experimental data obtained on a new class of biocompatible particles are presented, along with simulated data. The effects of coating size, proton exchange, and altered diffusion are examined. Simulations are presented confirming the effect of particle coatings on clustering-induced relaxivity changes, and an experimental system demonstrating the clustering effect is presented. 2) Development of a diffusion-dependent, off-resonance imaging protocol for magnetic nanoparticles. This work demonstrates an alternative approach, off-resonance saturation (ORS), for generating contrast sensitive to SPIO nanoparticles. This method leads to a calculated contrast that increases with SPIO concentration. Experimental data and a mathematical model demonstrate and characterize this diffusion-dependent, off-resonance effect. Dependence on off-resonance frequency and power are also investigated. 3) Development of a genetic MRI marker via in vivo magnetic nanoparticle synthesis. This work seeks to provide a gene expression marker for MRI based on bacterial magnetosomes, tiny magnets produced by naturally occurring magnetotactic bacteria. Here, magA is expressed in a commonly used human cell line, 293FT, resulting in the production of magnetic, iron oxide nanoparticles by these cells. MRI shows these particles can be formed in vivo utilizing endogenous iron and can be used to visualize cells positive for magA. These results demonstrate magA alone is sufficient to produce magnetic nanoparticles and that it is an appropriate candidate for an MRI reporter gene.
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Dey, Priyanka. "Hybrid polymer/metal nanoparticles with surface enhanced raman tracking for potential use in nanomedicine." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/74991/1/Priyanka_Dey_Thesis.pdf.
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This project was a preliminary step towards the development of novel methods for early stage cancer diagnosis and treatment. Diagnostic imaging agents with high Raman signal enhancement were developed based on tailored assemblies of gold nanoparticles, which demonstrated potential for non-invasive detection from deep under the skin surface. Specifically designed polymers were employed to assemble gold nanoparticles into controlled morphologies including dimers, nanochains, nanoplates, globular and core-satellite nanostructures. Our findings suggest that the Raman enhancement is strongly dependent on assembly morphology and can be tuned to adapt to the requirements of the diagnostic agent.
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Bernhard, Claire. "Synthèse d'agents chélatants bifonctionnels macrocycliques pour le marquage de molécules biologiques par des métaux : application en imagerie médicale." Thesis, Dijon, 2011. http://www.theses.fr/2011DIJOS024/document.
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L’imagerie moléculaire est devenue incontournable pour le diagnostic et le traitement de cancers. Cette discipline regroupe un ensemble de techniques telles que la tomodensitométrie (CT), l’Imagerie par Résonance Magnétique (IRM), l’imagerie optique ou encore l’imagerie nucléaire (tomographie par émission de positons TEP, tomographie d’émission monophotonique TEMP). Chacune de ces techniques possède ses propres avantages et inconvénients et ne peut apporter à elle seule des informations anatomiques et fonctionnelles suffisantes. Les travaux actuels sont portés sur la conception de systèmes dits multimodaux afin de combiner les avantages de différentes techniques, voire de bénéficier d’un effet synergique. De par leur sensibilité comparable et leur complémentarité, coupler l’imagerie nucléaire à l’imagerie optique devient alors avantageux. La conception des systèmes monomoléculaires (MOMIA) contenant deux fonctions détectables par imagerie nucléaire (complexe de radiométaux) et imagerie optique (sonde fluorescente) nécessite en amont la mise au point d’outils de synthèses performants. La première partie de ce travail de thèse est consacrée à la synthèse d’agents chélatants bifonctionnels à base de polyamines macrocycliques, destinés à une utilisation en imagerie médicale. Ces agents doivent présenter d’excellentes propriétés de coordination vis-à-vis du métal visé, et posséder une fonction de greffage pour assurer le couplage avec une biomolécule vectrice. L’accès à de tels systèmes a nécessité le développement d’outils de synthèse efficaces de précurseurs macrocycliques dérivés du cyclène et du 13aneN4. L’introduction sélective de diverses fonctions de greffage visant principalement les résidus de type lysine a permis la préparation de plusieurs familles de composés, dont certains ont pu être « bioconjugués» à des peptides ou anticorps au sein du laboratoire ou dans le cadre de diverses collaborations. Plus particulièrement, la facilité d’utilisation du système « DOTAGA anhydride » a permis l’introduction aisée d’unités DOTA sur des nanoparticules ou des anticorps monoclonaux. Egalement, l’introduction d’une fonction alcyne a permis l’accès à de nouvelles briques moléculaires préparées par « click chemistry ». Dans une seconde partie sont présentés les travaux relatifs à la synthèse d’agents bimodaux originaux. Pour accéder à de tels systèmes, l’introduction d’un fluorophore de la famille des bodipys a été envisagée. L’absence de travaux antérieurs relatifs au couplage d’une polyamine cyclique et une entité bodipy a nécessité la préparation préalable d’un système modèle « DOTA bodipy », permettant de s’assurer par des études photophysiques que la présence des complexes métalliques macrocycliques ne va pas, ou peu, interférer avec les propriétés de fluorescence du bodipy. L’utilisation d’un espaceur « acide aminé » a alors permis d’accéder à de nouveaux bodipys porteurs de deux groupes fonctionnels en position méso. La fonctionnalisation a posteriori de ces briques de construction a permis l’introduction en dernier lieu d’unités macrocycliques N- et/ou C- fonctionnalisés. La préparation de système émettant dans le proche I.R. a été également envisagéeMolecular imaging became a major tool for the diagnosis and the treatment of cancers. This research field includes different techniques, such as Tomography (CT), Magnetic Resonance Imaging (MRI), Optical Imaging or nuclear Imaging (PET Positron Emission Tomography, SPECT Single Photon Emission Computed Tomography). Each imaging modality has its own strengths and weaknesses, and thus, combining different and complementary systems can overcome inherent limitations associated with any one individual techniques and improve the accuracy of disease diagnosis and enhancing patient management. In particular dual-modality Optical/Nuclear imaging may find important preclinical and clinical applications. One possible approach seeks to fuse the two imaging systems into one molecule (MonOmolecular Multimodality Imaging Agent [MOMIA]) in order to ensure the same biodistribution of the two probes. Our strategy consists in combining a DOTA-like compound allowing complexation of radiometal for nuclear imaging (SPECT or PET) with a bodipy moiety, valuable probe those fluorescent properties can be finely adjusted. The first part of this work is dedicated to the synthesis of bifunctional chelating agents based on macrocyclic polyamines for medical imaging application. These compounds must show excellent coordination properties towards the aimed radiometal and possess a grafting function to allow the coupling with a biomolecule. Powerful and general routes for the synthesis of a wide range of N- and C-functionalized macrocycles derived from cyclen and 13aneN4 are described, which enable to access to a wide range of new BFCs by introduction of different functional groups reactive towards primary amines, such as carboxylic acid, isothiocyanate or anhydride function. Some compounds were conjugated to different biomolecules, such as peptides or antibodies. Morever, the introduction of an alkyne function yields a novel family of bifunctional agents allowing chemoselective attachment to functionalized biomolecules or to modified amino acids using « click chemistry ». In a second part, we focused on the introduction of a bodipy moeity to obtain new bimodal agents for dual Optical/Nuclear imaging. Interestingly, the attachment of the polyaminocarboxylate (DOTA derivative) to the bodipy makes it soluble in water and complexation of different metal cations of interest in the macrocyclic cavity does not significantly alter the luminescence properties of the whole system. In addition, the functionalization of the meso position by using an appropriate linker between the bodipy and DOTA-like units, i.e. a 4-nitrophenylalanine derivative, could provide a new bimodal tag for labeling antibodies or peptides. Optimisation of the second generation bodipy-DOTA, i.e. derivatization reaction to reach the near-IR range or introduction of C-functionalised macrocycles was also investigated
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Shah, N. H. "Exception diagnosis in open multi-agent systems." Thesis, Coventry University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425240.
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Md, Tohid Siti Farah. "Synthesis of potential cancer therapeutic and diagnostic agents." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/54438/.
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The need to find novel anticancer agents with better potency, efficacy and safety are highly demanded. Therefore, the first part of the study was aimed to synthesise new compounds based on stilbenes, indole-based isoxazoles and tricyclic anilides as potential antitumour agents, which later will be evaluated for their anticancer properties. The syntheses of substituted stilbenes were achieved via catalyzed or uncatalyzed methods, yielding stilbene analogues in moderate to good yields. Preliminary antiproliferative studies on four cancer cell lines (prostate, non-small lung, colon and breast) demonstrated their antiproliferative potential in the micromolar range. Unfortunately, the stilbenes were unable to inhibit the Wnt-signaling pathway in colon cancer cells. Next, the synthesis of indole-based isoxazole analogues was achieved via two different methods affording the compounds in low to moderate yields. The compounds will later be tested for their anticancer properties. The synthesis of 3289-8625 (tricyclic anilides) analogues, compounds which showed potent inhibitory activites on the PDZ domain of Dishevelled (PDZ- Dvl) as an important component in the Wnt signaling pathway was also carried out. The synthesis was achieved via various methods which gave rise to the formation of two analogues, which showed better binding affinities towards the PDZ-Dvl compared to the parent compounds. Finally, the therapeutic potential of the stilbenes was expanded to the synthesis of stilbene-based analogues as novel positron emission tomography (PET) imaging probes especially for the detection of p-amyloid plaques in brain, which is a hallmark of Alzheimer's disease. The syntheses of stilbenes were sought using fluorine-19, using methods that can later be adapted for 18F-PET radiochemistry. The syntheses of stilbenes attached to 19F-linker were afforded in good yields. Stilbenes directly attached to potassium trifluoroborate were synthesised in moderate yield. Nevertheless, the attempt to synthesise stilbene derivatives attached to a potassium trifluoroborate linker using novel procedures failed.
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Simmons, Suzanne Clare. "Development of Aptamers as Diagnostic and Therapeutic Agents." Thesis, Open University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.524784.
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Ren, Xiaoxu. "An agent-based system for distributed fault diagnosis." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401197.
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Grimaldo, Morón José Teófilo. "Contribution à la synthèse de macrocycles tétraphosphorés : ligands polydentates présentant un intérêt biomédical." Grenoble 1, 1987. http://www.theses.fr/1987GRE10161.
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Synthese de ligands macrocycles tetraphores, complexants potentiels de cations paramagnetiques (gd**(3+), fe**(3+)) et de nucleide radioactifs. Etude de la reactivite de ces ligands et des essais de complexation
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Nguyen, Vo Thu An. "Magnetic polyion complex micelles as therapy and diagnostic agents." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0138/document.
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Ce manuscrit de thèse présente la synthèse de nanoparticules d’oxyde de fer superparamagnétiques couramment appelées SPIONs servant d’agents de contraste pour l’imagerie par résonance magnétique (IRM) et la génération de chaleur pour la thérapie cellulaire par hyperthermie induite par champ magnétique radiofréquence (HMRF). Le contrôle des tailles et de la distribution en tailles des SPIONs et donc de leurs propriétés magnétiques a été obtenu en utilisant un copolymère arborescent G1 (substrat de polystyrène branché en peigne noté G0, greffé avec des groupements pendants poly(2-vinyle pyridine) ) comme milieu « gabarit », tandis que la stabilité colloïdale et la biocompatibilité des SPIONs ont été apportées par un procédé de poly-complexation ionique grâce à un copolymère double-hydrophile acide polyacrylique-bloc-poly(acrylate de 2-hydroxyéthyle) PAA-b-PHEAThis Ph.D. dissertation describes the synthesis of superparamagnetic iron oxide nanoparticles (SPIONs) designed to serve as magnetic resonance imaging (MRI) contrast agents and for heat generation in cellular radiofrequency magnetic field hyperthermia (MFH) treatment. Control over the size and size distribution of the iron oxide nanoparticles (NPs), and thus over their magnetic properties, was achieved using a G1 arborescent copolymer (comb-branched (G0) polystyrene substrate grafted with poly(2-vinylpyridine) side chains, or G0PS-g-P2VP) as a template. Good colloidal stability and biocompatibility of the SPIONs were achieved via the formation of polyion complex (PIC) micelles with a poly(acrylic acid)-block-poly(2-hydroxyethyl acrylate) (PAA-b-PHEA) double-hydrophilic block copolymer
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Matthews, Susan Elizabeth. "Synthesis of biodegradable polymers for delivery of diagnostic agents." Thesis, University of Bath, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296299.
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Kairdolf, Brad A. "Development of polymer-coated nanoparticle imaging agents for diagnostic applications." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31845.
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Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Nie, Shuming; Committee Member: Bao, Gang; Committee Member: Murthy, Niren; Committee Member: Varma, Vijay; Committee Member: Wang, Zhong Lin. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Serafini, Stefano. "Quality control agent: self-adaptive laser vibrometry for on line diagnostics." Doctoral thesis, Università Politecnica delle Marche, 2013. http://hdl.handle.net/11566/242695.
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In questa tesi verrà descritto come sia possibile aumentare la performance di sistemi di
misura basati sulla vibrometria laser, realizzando dei comportamenti auto-adattativi con lo
scopo di ridurre l’incertezza di misura.
I test sulle vibrazioni sono delle procedure ben note e largamente utilizzate per verificare la
conformità a specifiche di qualità dei prodotti che contengono parti in movimento. Questi
test posti alla fine di una linea di produzione forniscono delle informazioni utili per
descrivere la qualità di un prodotto prima del suo stoccaggio e vendita. Nell’industria
moderna la flessibilità e l’adattabilità sono dei fattori chiave per migliorare l’efficienza del
processo produttivo. Sia il controllo del processo industriale che il controllo qualità
dipendono dalla disponibilità di informazioni affidabili ottenute attraverso i test effettuati
sui prodotti finiti. Grazie alle elevate prestazioni di misura alle sue caratteristiche, la
vibrometria laser Doppler può giocare un ruolo fondamentale permettendo di realizzare
sistemi di misura flessibili che posso contenere algoritmi modulari e che possono attuare (i
sistemi soggetto) procedure auto-adattative.
Questo sistema è stato ottenuto aggiungendo al vibrometro laser a scansione una
telecamera. In questo modo il dispositivo è in grado di vedere e spostare il punto di misura
in posizioni differenti.
In questo sistema sono stati implementati diversi comportamenti auto-adattativi; spostando
il fascio laser è possibile effettuare il riposizionamento del punto di misura sulla lavatrice,
in modo da compensare gli eventuali posizionamenti errati che si hanno sulla linea di
produzione quando la lavatrice in esame viene posizionata sotto il sistema di misura
durante i controlli qualità. Dopo la compensazione di eventuali macro spostamenti della
lavatrice, viene eseguito una fase di ricerca automatica del massimo segnale doppler.
Questa ricerca viene condotta attraverso dei microspostamenti del fascio laser del
vibrometro sulla superficie della vasca della lavatrice attorno al punto di misura
prestabilito. L’obiettivo di questa fase è quello di minimizzare l’incertezza di misura
andando a cercare la regione della superficie che massimizza il segnale Doppler.
Un altro comportamento auto-adattativo consiste nella riconfigurabilità del sistema, cioè la
possibilità di utilizzare differenti algoritmi diagnostici in base alla necessità di effettuare o
meno un’analisi approfondita dell’elettrodomestico. Gli algoritmi scelti si riferiscono ai
diversi scenari produttivi che possono presentarsi all’interno dello stabilimento durante il
funzionamento della linea di produzione. Questo approccio modulare permette di
considerare la realtà della linea produttiva in tutte la sua complessità, permettendo di
svolgere un’analisi diagnostica che tiene in considerazione anche la qualità con cui si sono
svolte le operazioni di assemblaggio della lavatrice che affronta il controllo qualità.
Per poter utilizzare al meglio i comportamenti auto-adattativi, in questa tesi è stata
effettuata una ricerca delle cause di incertezza nella diagnostica industriale, viene mostrato
infatti come il valore RMS del segnale Doppler (signal quality-SQ) è fortemente correlato
all’incertezza di misura. Infatti, maggiore è il decadimento del SQ e tanto più la velocità di
vibrazione risulta essere affetta da incertezza. Gli esperimenti effettuati ci permettono di
dire che durante la vibrazione il valore del SQ è legato alla morfologia della superficie di
misura, e per intervalli di tempo sufficientemente brevi (10-15 secondi), il valore del SQ
dipende solo dalla posizione X-Y del raggio laser sulla superficie di misura. Questi fatti
permettono di utilizzare il valore del SQ(X.Y) come una funzione costo, e la diminuzione
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dell’incertezza di misura è un problema correlato all’ottimizzazione del valore del SQ
durante la misura di vibrazione. Per la strategia di ottimizzazione è stato utilizzato
l’algoritmo di down-hill (Nelder-Mead) e nella tesi vengono discussi i risultati ottenuti sul
SQ dall’applicazione dell’algoritmo.
Con le caratteristiche introdotte, il sistema di misura si trasforma in un Quality Control
Agent (QCA) che diventa parte di un sistema multi-agente (MAS) che ha il compito di
supervisionare l’operato della linea di produzione. In questa tesi vengono mostrati lo
scambio dei dati tra il sistema di misura e gli agenti dando vita ad un sistema produttivo
decentralizzato con caratteristiche di flessibilità e di auto-adattamento.
In modo da poter fornire delle informazioni affidabili agli altri agenti dell’infrastruttura, il
QCA associato al sistema di misura deve avere lapossibilità di capire il grado di confidenza
con cui i risultati della diagnosi vengono calcolati. Per questo motivo è stato concepito e
implementato un modello che permette di stimare il livello di confidenza delle informazioni
diagnostiche estratte dalle caratteristiche del segnale acquisito durante i test. In questo
modo, il QCA può fornire sia il valore globale della diagnosi che stimare il livello di
confidenza con cui la diagnosi è stata effettuata. Le informazioni provenienti dal QCA
vengo elaborate ed utilizzate dall’IMA (indipendent meta agent) per effettuare un controllo
di processo in modo da migliorare l’esecuzione della produzione.Vibration testing is a well established procedure for assessing the conformity to specifications of a variety of products, which contain moving parts. Typically at the end of an assembly line, a vibration test provides useful information for 100% quality control of products before packaging. In the appliance manufacturing sector vibration testing for online quality control is increasingly important. Laser Doppler Vibrometry (LDV) has been already used to perform such tests on-line and it has become an established measurement technique. In modern manufacturing industry flexibility and adaptability are key factors for the improvement of efficiency of production processes; both process control and product quality control depend on the availability of reliable information, and therefore on the quality of the data measured. For its non-contact nature and for its metrologic performance, laser vibrometry plays a more and more important and crucial role. This technique allows to realize flexible measurement systems that can implement adaptive and modular algorithms, comprising a large number of ready to use tools. In this thesis we will describe how it is possible to improve the performance of such systems by implementing self-adaptation and reconfigurability behaviors of the laser vibrometer aimed to reduce measurement uncertainty. Such behaviors are achieved by adding scanning mirrors and a dedicated camera, thus realizing a scanning LDV, which can displace the measurement beam at different locations. Self-adaptation (local adaptation) consists in the following behaviors: the system aims at the desired target point over the washing machine (WM) by displacing the laser beam so to compensate effects of WM mis-positioning due to production line inaccuracies. After this preliminary phase, the automatic search for sufficiently large Doppler signal starts. The system searches for an optimal optical signal by slightly displacing the laser beam in the surrounding of the desired target point thus optimizing measurement uncertainty. The system can support also reconfigurability (global adaptation), which consists in the possibility to plug-in/plug-out different post-processing algorithms for a deeper analysis of vibrations. For different production scenarios different diagnostic algorithms are chosen. This modular approach allows to consider the scenario of the production line and the quality of the operations carried out on the production line before the end product is made. In order to successfully use the self adaptation behavior to increase measurement accuracy, for this thesis a deep research of the causes correlated to uncertainty in industrial diagnostic has been made. It this work it is shown how the RMS amplitude of the Doppler signal (signal quality - SQ) is strictly correlated to measurement uncertainty, when SQ decreases then uncertainty affects the vibration velocity signal. Experimental data allow to say that SQ value is correlated to the morphology of the target surface and for a short period of time (10-15 s), so during the vibration the SQ value depends only on X-Y position of the laser beam on the target surface. These facts allow to use the SQ function as a cost function and the decrease the measurement uncertainty is a problem correlated to the optimization of the SQ value during the vibration measurements. The optimization strategy for the measurement enhancement achieved by the down-hill algorithm (Nelder-Mead algorithm) and its effect on signal quality (SQ) improvement are discussed. ii With these features, this system is designed as a Quality Control Agent (QCA) and it is part of a Multi Agent System (MAS) that supervises all the production line. This thesis also shows the data exchange between the measurement system and other agents in order to realize a decentralized manufacturing system. In fact, in a distributed system, the estimation of the confidence level of the information provided by other agents plays an important role. The QCA associated to the measurement system has to be able to understand the confidence level of the diagnostic results provided. To understand the confidence level of the diagnostic information extracted from a feature, an uncertainty estimate model applied to a vibration signal acquired from a washing machine has been conceived and implemented. In this way, the QCA can provide the overall diagnosis for the WM and estimate the uncertainty level with which the diagnosis has been performed. These information are used by the independent meta agent (IMA) to perform a trend analysis and elaborate suggestions and warnings to improve the process and product execution.
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Chin, Chien Ting. "Modelling the behaviour of microbubble contrast agents for diagnostic ultrasound." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ59006.pdf.
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Cheung, Shing-chung, and 張成忠. "Novel contrast agents for magnetic resonance imaging." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841550.
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Cheung, Shing-chung. "Novel contrast agents for magnetic resonance imaging." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841550.
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Goumas, Dimitrios. "Possibilites de detection d'erwinia chrysanthemi pv. Dianthicola (hellmers) dickey 1979-agent de la bacteriose du dahlia sp. Evaluation des methodes immunoenzymatiques pour le controle sanitaire du materiel de propagation." Paris 6, 1987. http://www.theses.fr/1987PA066405.
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La bacteriose a e. Chrysanthemi pv. Dianthicola (echr) facteur limitant de la production du dahlia est transmise par la multiplication vegetative. Afin de proposer une methode de diagnostic plus precise que la detection visuelle, les methodes immunoenzymatiques ont ete etudiees et adaptees pour la detection d'echr dans les tissus du dahlia. La methode das-elisa (double antibody sandwich) est evaluee par rapport aux methodes de diagnostic de reference (isolement et immunofluorescence). Son utilisation, pour l'analyse sanitaire du materiel de propagation vis-a-vis d'echr seul et associe eventuellemnt a la mosaique du dahlia (damy), est etudiee en vue d'une selection sanitaire. Les etudes effectuees pour optimiser les reactifs, pour determiner les parametres pouvant modifier la reaction antigene-anticorps
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Marques, Gonçalo Nogueira. "Clinical approach to respiratory mucormycosis in a bottlenose dolphin (Tursiops truncatus) calf under human care." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2019. http://hdl.handle.net/10400.5/19336.
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Dissertação de Mestrado Integrado em Medicina VeterináriaSeveral fungi are described to cause invasive infections in dolphins, the respiratory system being a common site of involvement. Mucormycosis is considered one of the most devastating fungal infections in dolphins, associated with an elevated mortality rate, where hyphae are capable of invading blood vessels, producing tissue infarction and necrosis. A one-year-old male bottlenose dolphin (Tursiops truncatus) calf presented with a history of recurrent episodes of leukocytosis and occasional respiratory signs. During a routine faecal examination, a myriad of hyphae were found. Fungal culture revealed a mucormycete isolation, the aetiologic agent of mucormycosis. Molecular studies allowed to identify Cunninghamella bertholletiae. Thoracic radiographs showed the presence of a bronchoalveolar pattern on both the right and left lung apexes. A bronchoscopy was performed, which revealed multiple whitish lesions, diffusely distributed on the tracheal and bronchial submucosa. The antifungal therapy prescribed was a combination of posaconazole and aerosolized liposomal amphotericin B. Adjunctive therapies included bromhexine, vitamin C, vitamin B complex, probiotics, silymarin, Imuno-2865™ and ozone therapy. Follow-ups were conducted with haematology and blood biochemistry, faecal and sputum culture and direct microscopy, and bronchoscopies. There was a good overall response to treatment and antifungal therapy was discontinued. However, the infection relapsed and posaconazole therapy was restarted. Serum concentrations of posaconazole were retrospectively evaluated and the set of results did not appear to show subtherapeutic concentrations as a plausible explanation for the relapse. Although complete clinical resolution was not obtained during the timeframe considered, this case corroborates the idea that medical management of mucormycosis is possible, especially with a prompt diagnosis and treatment as well as a tight follow-up protocol. As described in the literature, mucormycosis treatment may take several years and relapses are common.
RESUMO - Maneio médico de mucormicose respiratória numa cria de golfinho-roaz (Tursiops truncatus) em contexto zoológico - Várias espécies de fungos estão descritas como agentes etiológicos de infeções invasivas em golfinhos, sendo o sistema respiratório um dos locais comuns de infeção. A mucormicose é uma das infeções fúngicas invasivas com efeitos mais devastadores, associada a uma elevada taxa de mortalidade em cetáceos. Nesta dissertação é apresentado um caso clínico referente a uma cria de golfinho-roaz (Tursiops truncatus) com um ano de idade, com uma história clínica que incluía episódios recorrentes de leucocitose e ocasionais sinais clínicos de etiologia respiratória. Como parte do programa de medicina preventiva instituído, uma análise microscópica de fezes permitiu a visualização de estruturas fúngicas. A cultura fúngica permitiu o isolamento de um mucormicete, o agente etiológico da mucormicose, e através de PCR e sequenciação foi possível identificar Cunninghamella bertholletiae. Estudos imagiológicos demonstraram a presença de um ligeiro padrão broncoalveolar nos ápices pulmonares e o exame endoscópico permitiu visualizar múltiplas lesões esbranquiçadas, difusamente distribuídas pelas mucosas traqueal e brônquica. O tratamento antifúngico consistiu na administração de comprimidos gastrorresistentes de posaconazol e nebulizações com anfotericina B lipossómica. Tratamentos adjuvantes incluíram bromexina, silimarina, suplementação vitamínica, probióticos, Imuno-2865TM e ozonoterapia. O acompanhamento do caso foi feito com base em dados hematológicos e bioquímicos, análises microscópicas/cultura de fezes e exsudado respiratório e broncoscopias. O tratamento com posaconazol foi descontinuado após 95 dias de terapia, tendo em conta os resultados constantemente negativos na cultura e observação microscópica de amostras fecais e exsudado respiratório. No entanto, verificou-se a recidiva da infeção e o tratamento antifúngico foi recomeçado. As concentrações séricas do fármaco ao longo do caso clínico foram retrospetivamente analisadas e esta monitorização permitiu descartar a hipótese de não terem sido atingidas concentrações séricas terapêuticas como causa da recidiva da infeção. Apesar de não ter existido uma completa resolução clínica no período considerado, este caso corrobora o facto do maneio médico da mucormicose em cetáceos ser possível, através de um diagnóstico e tratamento precoces, além de um plano apertado de seguimento clínico. Como descrito na bibliografia, o tratamento da mucormicose pode demorar vários anos e recidivas são comuns.
N/A
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Stöckmann, Henning. "The development of new agents for molecular imaging in cancer." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610030.
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Barlas, Irtaza. "A Multiagent Framework for a Diagnostic and Prognostic System." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5290.
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A Multiagent Framework for a Diagnostic and Prognostic System
Irtaza Barlas
124 Pages
Directed By: Dr. George Vactsevanos
The shortcomings of the current diagnostic and prognostic systems stem from the limitations of their frameworks. The framework is typically designed on the passive, open loop, static, and isolated notions of diagnostics, in that the framework does not observe its diagnostic results (open-looped), hence can not improve its performance (static). Its passivity is attributed to the fact that an external event triggers the diagnostic or prognostic action. There is also no effort in place to team-up the diagnostic systems for a collective learning, hence the implementation is isolated.
In this research we extend the current approaches of the design and implementation of diagnostic and prognostic systems by presenting a framework based upon Multiagent systems. This research created novel architectures by providing such unique features to the framework, as learning, reasoning, and coordination. As the primary focus of the research the concept of Case-Based Reasoning was exploited to reason in the temporal domain to generate better prognosis, and improve the accuracy of detection as well as prediction. It was shown that the dynamic behavior of the intelligent agent helps it to learn over time, resulting in improved performance.
An analysis is presented to show that a coordinated effort to diagnose also makes sense in uncertain situations when there are certain number of systems attempting to communicate certain number of failures, since there can be high probability of finding a shareable experience.
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Moreau, Mathieu. "Marquage de molécules biologiques par des complexes de radiométaux à base de polyamines macrocycliques." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00796881.
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Ce travail de thèse réalisé à l'Institut de Chimie Moléculaire de l'Université de Bourgogne porte dans un premier temps sur la synthèse d'agents chélatants bifonctionnels adaptés à la chélation de radiométaux trivalents, notamment l'indium-111. La plus grande partie de ce travail a ensuite consisté à réaliser le greffage d'un agent chélatant bifonctionnel dérivé du DOTA sur différents anticorps ou fragments d'anticorps monoclonaux : le trastuzumab (anti HER2, traitement de cancers du sein), le cétuximab (anti EGFR, traitement de nombreux cancers, dont le cancer colorectal) et l'abciximab (antiagrégant plaquettaire). Une attention particulière a été apportée à la caractérisation des différents immunoconjugués. La dernière étape de ce travail de thèse porte sur le radiomarquage à l'indium-111 de deux immunoconjugués préparés : le trastuzumab et le cétuximab. Ces étapes de radiomarquage nous ont permis de déterminer la fraction immunoréactive et l'affinité de chaque radiotraceur. Nous avons ainsi pu étudier la biodistribution in vivo de ces radiotraceurs chez la souris par imagerie SPECT-CT. Nous avons également développé une méthode de greffage originale pour le marquage d'un fragment d'anticorps de type Fab, l'abciximab, dans le but de suivre la biodistribution de cet antiagrégant plaquettaire. Enfin, nous avons également validé le concept d'imagerie multimodale à travers le greffage et le radiomarquage d'un agent bimodal pour l'imagerie optique et la SPECT sur des lipopolysaccharides bactériens. Les travaux réalisés nous ont permis d'acquérir un savoir faire en matière de greffage d'anticorps et de radiomarquage. Les résultats obtenus permettent d'envisager le greffage d'autres anticorps ou biomolécules, ainsi que l'utilisation d'autres radionucléides pour l'imagerie PET ou la radioimmunothérapie
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Pires, Layla. "Optical strategies for diagnosis and treatment of melanoma." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-01122017-154608/.
Full textAbstract:
Melanoma is a pigmented tumor that originates from the melanocytes; pigmented cells present throughout the body, including skin and iris. The cutaneous form is the most common type, and it represents about 5% of the skin tumors diagnosed in Brazil. Although it does not have a high incidence, it represents about 80% to 85% of all skin tumor deaths. The second most frequent type of melanoma is ocular. It represents 5% of all melanoma cases and is a potentially lethal disease, especially when it causes metastasis. The main therapeutic approach for melanomas, in general, is surgery, with resection of the cutaneous lesion or enucleation in the case of ocular melanoma. Other techniques such as adjuvant immunotherapy, palliative chemotherapy, and radiotherapy are also used. However, they have low efficacy and several side effects. Photodynamic therapy is a therapeutic modality based on the interaction of light at specific wavelength and photosensitizer, in the presence of molecular oxygen, leading the cell to death. As melanoma is a pigmented cancer, it usually does not respond well to photodynamic therapy due to the high absorption of light on the surface of the tumor, making volumetric eradication impossible. This project investigated optical strategies for the diagnosis and treatment of melanoma. For the diagnosis, it was evaluated the fluorescence lifetime technique to differentiate melanoma and normal skin. A sensitivity of 99.4%, specificity of 97.4% and accuracy of 98.4% were achieved using linear discrimination analysis. For the cutaneous melanoma treatment, PDT combined to optical clearing agents (OCAs) was investigated. Vascular and cell-target photosensitizers were evaluated combined or not to OCAs. OCA improved PDT response in all pigmented tumors treated, but the best results were achieved when a dual-photosensitizer treatment combined to OCA was performed. The treatment of conjunctival melanoma was conducted using 2-photon excitation photodynamic therapy. The advantage of this technique is the use of infrared light, in a wavelength that melanin has a low absorption, improving the light penetration into the tumor. The tumor histology shows that apoptosis was induced only at the treatment site, with no damage to the surrounding tissue. Additionally, a single TPE-PDT session could treat the entire tumor.O melanoma é um tumor pigmentado que surge dos melanócitos, células pigmentadas presentes em todo o corpo, incluindo a pele e a íris. A forma cutânea é a mais comum e representa cerca de 5% dos tumores cutâneos diagnosticados no Brasil. Embora não tenha uma alta incidência, representa cerca de 80% a 85% de todas as mortes por tumor de pele. O segundo tipo de melanoma mais frequente é o ocular. Representa 5% de todos os casos de melanoma e é uma doença potencialmente letal, especialmente em casos de metástase. A principal abordagem terapêutica para melanomas, em geral, é a cirurgia, com ressecção da lesão cutânea ou enucleação no caso do melanoma ocular. Outras técnicas, como imunoterapia adjuvante, quimioterapia paliativa e radioterapia também são usadas, porém, apresentam baixa eficiência e muitos efeitos colaterais. A terapia fotodinâmica é uma modalidade terapêutica baseada na interação da luz em um comprimento de onda específico e um fotossensibilizador, na presença de oxigênio molecular, levando a célula à morte. Como o melanoma é um câncer pigmentado, geralmente não responde bem à terapia fotodinâmica devido à alta absorção de luz na superfície do tumor, impossibilitando a erradicação volumétrica. Este projeto investigou estratégias ópticas para o diagnóstico e tratamento do melanoma. Para o diagnóstico, foi avaliada a técnica de tempo de vida de fluorescência para distinguir melanoma de pele normal. Utilizando análise de discriminação linear, obteve-se uma sensibilidade de 99,4%, especificidade de 97,4% e precisão de 98,4%. Para o tratamento de melanoma cutâneo, a PDT combinada com clareadores ópticos (OCAs) foi investigada. Um fotossensibilizador que tem como alvo vaso sanguíneo e um fotossensibilizador de alvo celular foram avaliados combinados ou não com OCAs. OCAs são soluções hiperosmóticas que desidratam o tecido, diminuindo o espalhamento da luz e melhorando a penetração de luz em profundidade. OCA melhorou a resposta de PDT em todos os tumores melanóticos tratados, mas os melhores resultados foram obtidos quando a PDT foi realizada com a combinação dos fotossensibilizadores e clareador óptico em uma única sessão. O tratamento do melanoma conjuntival foi realizado utilizando a terapia fotodinâmica por excitação de 2 fótons (TPE-PDT). A vantagem desta técnica é o uso de luz na região do infravermelho, em um comprimento de onda que melanina tem baixa absorção, melhorando a penetração de luz no tumor. A histologia do tumor mostrou que a apoptose foi induzida apenas no local do tratamento, sem danos no tecido adjacente. Além disso, uma única sessão de TPE-PDT foi capaz de tratar todo o tumor.
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Davoodi, Samirmi Farhad. "Multi-agent and knowledge-based system for power transformer fault diagnosis." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/14455/.
Full textAbstract:
Transformer reliability and stability are the key concerns. In order to increase their efficiency, an automatic monitoring and fault diagnosing of the power transformers are required. Dissolved Gas Analysis (DGA) is one of the most important tools to diagnose the condition of oil-immersed transformer. Agents technology as a new, robust and helpful technique, successfully applied for various applications. Integration of the Multi-Agent System (MAS) with knowledge base provides a robust system for various applications, such as fault diagnosis and automated actions performing, etc. For this purpose, the present study was conducted in the field of MAS based on Gaia methodology and knowledge base. The developed MAS followed by Gaia methodology represents a generic framework that is capable to manage agents executions and message delivery. Real-time data is sampled from a power transformer and saved into a database, and it is also available to the user on request. Three types of knowledge-based systems, namely the rule-based reasoning, ontology and fuzzy ontology, were applied for the MAS. Therefore, the developed MAS is shown to be successfully applied for condition monitoring of power transformer using the real-time data. The Roger’s method was used with all of the knowledge-based systems named above, and the accuracy of the results was compared and discussed. Of the knowledge-based systems studied, fuzzy ontology is found to be the best performing one in terms of results accuracy, compared to the rule-based reasoning and ontology. The application of the developed fuzzy ontology allowed to improve the accuracy by over 22%. Unlike the previous works in this field, that were not capable of dealing with the uncertainty situations, the present work based on fuzzy ontology has a clear advantage of successfully solving the problem with some degree of uncertainty. This is especially important, as the most of the real-world situations involve some uncertainty. Overall, the work contributes the use of the knowledge base and the multi-agent system for the fault diagnosis of the power transformer, including the novel application of fuzzy ontology for dealing with the uncertain situations. The advantages of the proposed method are the ease of the upgrade, flexibility, efficient fault diagnosis and reliability. The application of the proposed technique would benefit the power system reliability, as it would result in reduction of the number of engineering experts required, lower maintenance expenses and extended lifetime of power transformer.