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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

[en] BRAZILIAN DEMAND FOR CALIBRATION OF MEASURING INSTRUMENTS FOR MAGNETIC QUANTITIES / [pt] DEMANDA POR CALIBRAÇÃO DE INSTRUMENTOS DE MEDIÇÃO DE GRANDEZAS MAGNÉTICAS NO BRASIL

ANTONIO FERNANDO MACIEL DE MENDONCA 24 July 2015 (has links)
[pt] A confiabilidade dos resultados das medições é garantida por meio da rastreabilidade às unidades do Sistema Internacional de Unidades (SI). A cadeia de rastreabilidade dos padrões metrológicos dos diversos laboratórios de cada país é implantada, mantida e referenciada aos padrões internacionais pelos Institutos Nacionais de Metrologia (INM). No Brasil, apesar de uma demanda crescente originária de diversos setores (regulatório, industrial, serviços, etc.), a rastreabilidade de grandezas magnéticas não foi implantada. No presente trabalho é realizado levantamento da demanda nacional por rastreabilidade metrológica de grandezas magnéticas e caracterizadas as competências, iniciativas e infraestrutura nacionais já disponíveis. As iniciativas para realização das unidades SI de grandezas magnéticas já em implantação no INM apresentam a abrangência necessária ao atendimento das demandas regulatórias recentemente estabelecidas no país, mas não são suficientes para atender às faixas de intensidade e de frequência de densidade de fluxo magnético correspondentes às demandas identificadas nos setores da indústria e de pesquisa e desenvolvimento. / [en] The traceability to the International System of Units (SI) guarantees the reliability of measurement results. For each country, the metrological traceability chain to an international measurement standard is supported by the National Metrological Institute (NMI). Despite a growing demand from various sectors (regulatory, industrial, services, etc.), the traceability of magnetic quantities has not been implemented in Brazil. In the present work, the national demand for metrological traceability of magnetic measurement results is investigated; and the potential infrastructure and competencies already available are characterized. The measurement infrastructure presently being built for realization of the SI unit of magnetic flux density enables compliance to the regulatory requirements recently established, but it is not sufficient for the range of magnitudes and frequencies of this quantity that have been identified in other sectors, like Industry and Research e Development .
2

Développement de méthodes de référence pour spectrométrie de masse pour le dosage de biomarqueurs de la maladie d'Alzheimer / Development of reference methods for mass spectrometry for the assay of Alzheimer's disease biomarkers

Bros, Pauline 31 May 2016 (has links)
En raison du vieillissement de la population, la maladie d’Alzheimer (MA) est devenue un problème majeur en santé public. Le dosage des biomarqueurs présents dans le liquide céphalorachidien (Ab 1-42, tau et hepcidine) étant de bons indicateurs précoces de l’apparition et de l’évolution de la MA, il paraît essentiel de disposer de mesures fiables. Etablir la traçabilité métrologique des résultats aux unités du système international par le biais de méthodes de référence primaires ou de matériaux de référence certifiés d’ordre supérieur est un moyen privilégié pour évaluer et améliorer la fiabilité et la comparabilité des résultats dans le temps et entre les laboratoires. Des méthodes de dosages par LC-MS/MS pour ces trois biomarqueurs ont été développées et validées. Pour le dosage de l’hepcidine, la pureté de l’étalon peptidique a fait l’objet d’une caractérisation approfondie par spectrométrie de masse haute résolution qui permettra de standardiser les dosages de routine à l’échelle internationale.Mots clés : Peptides b amyloïdes, Protéine tau, Hepcidine, Biomarqueurs, Protéomique Clinique, Traçabilité métrologique, Spectrométrie de masse / Due to the aging of population, Alzheimer’s disease (AD), is becoming a major public health concern. Measurement of biomarkers (Amyloid Beta, tau and hepcidin) in cerebrospinal fluid being early diagnostic indicators of AD, reliable measurements are needed to detect and quantify them accurately. Establishing metrological traceability of results to the International System of Units through primary reference methods or higher-order certified reference materials is a privileged mean to assess and improve results accuracy and comparability across laboratories. Assays for these three biomarkers were set up and validated by LC-MS/MS. The hepcidin standard was further characterized by high resolution mass spectrometry, paving the road toward standardization at the international scale of results.Key words : b amyloids peptides, Tau protein, Hepcidin, Biomarkers, Clinical proteomic, Metrological traceability, Mass spectrometry
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Caractérisation métrologique de méthodes de références primaires candidates pour l’énumération des lipoprotéines et le dosage de l’hémoglobine glyquée HbA1c / Metrological characterization of candidate primary reference methods for the enumeration of lipoprotein particles and the absolute quantification of glycated hemoglobin HbA1c

Clouet, Noémie 11 September 2017 (has links)
En biologie clinique, disposer de mesures fiables et comparables, indépendamment du temps et du laboratoire, est primordial afin de permettre une prise en charge et un suivi adaptés des patients. Le moyen privilégié est d’établir la traçabilité métrologique des résultats de mesure aux unités du système international (SI), notamment par le biais de méthodes de référence et de matériaux de référence certifiés d’ordre supérieur. Ces travaux de thèse se sont attachés à caractériser deux méthodes de référence primaires candidates. Une méthode d’énumération absolue des lipoprotéines par ES-DMA pour l’évaluation du risque cardiovasculaire a été développée et caractérisée. Les résultats obtenus ont mis en évidence certaines limitations instrumentales rendant l’établissement de la traçabilité au SI difficile. Malgré les avantages certains de cette méthode pour l’analyse avancée de lipoprotéines, la fidélité et la robustesse des mesures ne sont pas suffisantes pour la considérer comme méthode de référence primaire. Une méthode de quantification de l’hémoglobine glyquée HbA1c, un biomarqueur du diabète sucré, par LC-MS/MS associée à la dilution isotopique a été mise en place et validée. La traçabilité au SI des résultats de dosage a été établie, toutefois, les incertitudes de mesures demeurent élevées et la comparabilité avec la méthode de référence IFCC reste à évaluer sur un nombre plus significatif d’échantillons et de laboratoires. Pour conclure, ces travaux ont mis en évidence les défis associés à la mise en place de nouvelles chaînes de traçabilité ainsi que les problématiques liées au développement de méthodes de référence primaires pour le dosage de biomarqueurs complexes. / Ensuring reliability and between-laboratory comparability of in-vitro diagnostic test results is essential for appropriate and internationally harmonized decision making and patient follow-up. To this end, a privileged way is to establish results metrological traceability to the international system of units (SI) through the development of primary reference methods and higher order reference materials. This thesis aimed at characterizing two candidate primary reference procedures.A method for lipoprotein absolute quantification by ES-DMA for cardiovascular diseases risk assessment was developed and characterized. Results evidenced some advantages of this method compared to other advanced lipoprotein testing assays, but some instrumental weaknesses make the establishment of results traceability to the SI difficult in the current state-of-the-art. Precision and robustness are additionally not sufficient for this method to be considered as a primary reference method.A method for the quantification of glycated hemoglobin HbA1c, a biomarker of diabetes mellitus, by LC/MS/MS associated to isotopic dilution was implemented and validated. Results traceability to the SI units could successfully be established. However, measurement uncertainties remain large and comparability with the IFCC reference method is still to be further assessed on a significant number of samples and laboratories.To conclude, this study highlighted the challenges associated with the implementation of new traceability chains and the difficulties related to the development and characterization of primary reference procedures for the quantification of complex biological markers.
4

Návrh vhodného etalonu délky pro oblast nanometrologie na pracovištích ČMI Brno a CEITEC Brno / Design of a suitable length standard for nanometology at the CMI Brno and CEITEC Brno

Češek, Jakub January 2019 (has links)
The thesis deals with the design of a suitable length standard for nanometrology. This length standard will be used for metrological traceability of the Rigaku nano3DX located at CEITEC Brno and the SIOS NMM-1 device which is located at ČMI Brno. The first part is focused on the description of these measuring instruments, the analysis of their metrological traceability requirements and the requirements for the material length standard. The second part is devoted to the concrete possibilities of the etalon design, 3D printing of the prototype of the standard and verification of its dimensional compatibility. At the end of the thesis, the evaluation and selection of the appropriate standard design is made.
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[en] PROPOSED NEW CRITERIA FOR PERFORMANCE EVALUATION OF CLINICAL LABORATORIES BY MEANS OF PROFICIENCY TESTS / [pt] PROPOSTA DE NOVOS CRITÉRIOS PARA AVALIAÇÃO DE DESEMPENHO DE LABORATÓRIOS CLÍNICOS POR MEIO DE ENSAIOS DE PROFICIÊNCIA

DIOGO JOSÉ DA SILVA JERÔNIMO 15 August 2017 (has links)
[pt] A participação de laboratórios clínicos em programas de ensaio de proficiência é uma importante ferramenta para gestão da qualidade. A maior parte das avaliações de desempenho de laboratórios clínicos por ensaio de proficiência se realiza com base no critério Z-Score, cujo valor designado é o consenso de resultados obtidos pelos participantes da rodada de proficiência, que é fortemente dependente da qualidade dos sistemas analíticos dos participantes. Utilizando uma base de dados fornecida por um provedor de ensaios de proficiência acreditado pelo INMETRO, este trabalho compara o desempenho de critérios para a avaliação da proficiência de laboratórios clínicos para medição de glicose. Consideraram-se não só critérios comumente utilizados, mas também novos critérios propostos que independem do consenso, baseados apenas em parâmetros associados ao valor designado pelo material de referência. As discrepâncias de classificação de desempenho dos laboratórios em função dos critérios de avaliação empregados indicaram inadequações da classificação baseada em critérios com parâmetros afetados pelo consenso entre participantes. O estudo também permitiu caracterizar o desempenho dos sistemas analíticos empregados pelos participantes, evidenciando-se uma discrepância significativa entre seus resultados. Os resultados do presente trabalho possibilitam analisar o impacto dos critérios utilizados no ensaio de proficiência para a adequada avaliação do desempenho dos laboratórios, contribuindo, assim, para a garantia da confiabilidade dos diagnósticos clínicos e condutas terapêuticas. / [en] The participation of clinical laboratories in proficiency testing programs is an important tool for quality management. Most evaluations of clinical laboratory performance by proficiency testing are carried out based on the Z-Score criterion; whose assigned value is the consensus of results obtained by the participants of the round, which is heavily dependent on the quality of analytical systems of participants. Using a database provided by a proficiency testing provider accredited by INMETRO, this paper compares the performance of criteria for the assessment of proficiency of clinical laboratories for measuring glucose. The analysis considered not only commonly used criteria, but also new proposed criteria that are independent of the consensus effect, based only on parameters associated with the assigned value defined by the reference material. The observed discrepancies in the performance rating of laboratories, according to the evaluation criteria employed, allowed the evidencing of inadequacies in the classifications based on criteria using parameters affected by the consensus among participants. The study also characterized the performance of analytical systems employed by the laboratories, evidencing a significant discrepancy between the results its. The present work allowed a better understanding of the impact of criteria applied in proficiency testing programs on the adequacy of evaluation of laboratories performance, thus contributing to ensuring the reliability of clinical diagnostics and therapeutical procedures.
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Développement de méthodes de référence pour les biomarqueurs du bilan lipidique : application au contrôle qualité en biologie clinique / Development of reference methods for lipid profile biomarqueurs : application to quality controle in clinical chemistry

Heuillet, Maud 13 December 2013 (has links)
En biologie clinique, il est indispensable de disposer de mesures fiables et comparables dans le temps et entre les laboratoires afin de permettre un dépistage et un suivi appropriés des patients. Pour cela, il est indispensable d’établir leur traçabilité métrologique aux unités du système international notamment par des méthodes de référence primaires ou des matériaux de référence certifiés (MRC) d’ordre supérieur. Ces travaux de thèse ont consisté à développer et valider des méthodes de référence pour le cholestérol total, les triglycérides, le HDL-cholestérol et le LDL-cholestérol. Leur valeur ajoutée par rapport à une valeur consensuelle a été démontrée lors d’évaluations externes de la qualité. Elles ont également permis de certifier un MRC qui pourra être utilisé pour le contrôle qualité et/ou l’étalonnage des méthodes de routine. Nous avons montré que le MRC était commutable pour la plupart des méthodes de routine pour les différents biomarqueurs, ce qui a permis de l’utiliser pour évaluer leur justesse. Les méthodes de routine avaient généralement tendance à sous-estimer la concentration en triglycérides (en particulier aux valeurs basses) et à surestimer nettement la concentration de cholestérol total et de LDL-cholestérol (en particulier aux concentrations proches du seuil de décision clinique), ce qui se traduit par une augmentation du nombre de faux-positifs (patients traités à tort). Une approche de correction de non commutabilité a également été proposée afin de permettre l’utilisation de matériaux non commutables pour évaluer la justesse. Pour conclure, ces travaux ont démontré l’importance de disposer de méthodes de référence ainsi que de MRC commutables / Reliable measurements in medical biology are essential for early screening and appropriate follow-up of patients. Ensuring metrological traceability of clinical measurements to higher order reference methods or certified reference materials enables to obtain comparable results over time and between different laboratories that could use different methods to quantify the same biomarker.In this study, reference methods were developed and validated for lipid profile biomarkers (total cholesterol, triglycerides, HDL-C, and LDL-C). Their value added in proficiency testing schemes was demonstrated against consensus mean. They were also used to characterize a certified reference material (CRM) that may be used both as quality control and/or calibrator of field methods. The CRM was shown to be commutable for most field methods and lipid profile biomarkers, which proved it was suitable to assess trueness. Results of our multicenter study showed that field methods tend to underestimate triglycerides (particularly at low concentrations) and overestimate total cholesterol and LDL-C (especially around the clinical threshold), resulting in false positives and significant patient misclassifications. An approach of non-commutanility correction was also presented to allow trueness assessment with non-commutable samples. In conclusion, this work highlights the importance of using reference methods and also commutable CRM to rigorously assess accuracy of field methods used in clinical laboratories
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Návrh modernizace přístroje Mesing pro kalibraci koncových měrek nad 100 mm / Proposal of modernizing the Mesing instrument to calibrate the gauge blocks over 100 mm

Sokl, Antonín January 2019 (has links)
The aim of this thesis, which deals with the modernization of the Zeiss/Tesa device, which is designed to calibrate the gauge blocks, is to provide a detailed analysis of the current state of the art of this instrument and to search for gauge blocks calibration requirements. The introductory part of the thesis is devoted to the definition of basic metrological concepts and terms. One of the separate chapters contains a elaborate description of the Zeiss/Tesa device and the possibilities of its modernization. A qualified estimation of the measurement uncertainty is determined in the practical part of the thesis and a simulation of the measurement uncertainty is performed using the Monte Carlo method. The final chapter contains the technical documentation of the proposed modernization.
8

[pt] AVALIAÇÃO DE ANALISADOR HEMATOLÓGICO BASEADO EM MEDIÇÕES ÓPTICAS DIRETAS USANDO LED AZUL PARA CONTAGEM DIFERENCIAL DE LEUCÓCITOS / [en] EVALUATION OF HEMATOLOGY ANALYZER BASED ON DIRECT OPTICAL MEASUREMENTS USING BLUE LED FOR DIFFERENTIAL LEUKOCYTE COUNTING

VICENTE MONTEIRO LORENZON 14 January 2020 (has links)
[pt] Os analisadores hematológicos são sistemas de medição que permitem identificar elementos sanguíneos, incluindo a contagem diferencial dos cinco tipos de leucócitos encontrados no sangue periférico: neutrófilos, linfócitos, monócitos, eosinófilos e basófilos. Devido à inexistência de materiais de referência certificados ou métodos de referência para a análise diferencial de leucócitos, tem sido habitual avaliar o desempenho de novos analisadores comparando-os com sistemas tradicionalmente disponíveis e bem consolidados. Em 2015, foi lançada uma nova tecnologia portátil e de baixo custo, o modelo DxH500 (Beckman Coulter), baseada na perda axial de luz usando LED azul como emissor, combinada à medição de impedância. O presente trabalho compara o desempenho do DxH500 com um modelo bastante utilizado desde seu lançamento em 2001 para exames laboratoriais em larga escala, o modelo LH750 (Beckman Coulter), baseado na combinação dos princípios de impedância, condutividade e dispersão de luz (VCS). No estudo foram examinadas 310 amostras pareadas. A análise comparativa entre os resultados fornecidos por cada dispositivo indicou uma boa correlação para a caracterização de neutrófilos, linfócitos, monócitos e eosinófilos. Apesar da reduzida correlação observada para a contagem de basófilos, esse resultado não apresenta relevância clínica já que os valores obtidos para as amostras avaliadas foram muito reduzidos, inferiores aos limites de referência. Embora a análise comparativa realizada tenha apontado para um desempenho equivalente utilizando-se tecnologias com princípios diversos, a adequada avaliação dos dispositivos de análise hematológica requer o desenvolvimento de materiais de referência certificados, uma demanda fundamental para a garantia da confiabilidade na quantificação diferencial de leucócitos. / [en] Hematology analyzers are measurement systems that allow the identification of blood elements, including differential counting of the five types of leukocytes found in peripheral blood: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Because of the lack of certified reference materials or reference methods for differential leukocyte analysis, it has been customary to evaluate the performance of new analyzers by comparing them with traditionally available and well-established systems. In 2015, a new low-cost, portable technology was introduced, the Beckman Coulter DxH500 model, based on the axial loss of light using blue LED as a combined transmitter for impedance measurement. The present work compares the performance of the DxH500 with a widely used model since its launch in 2001 for large-scale laboratory tests, the Beckman Coulter model LH750, based on the combination of impedance, conductivity and scatter (VCS). In the study, we examined 310 paired samples. The comparative analysis between differential leukocyte evaluation results provided by each device indicated a good correlation for the characterization of neutrophils, lymphocytes, monocytes, and eosinophils. Despite the low correlation observed for basophil counts, this result is not clinically relevant since the values obtained for the evaluated samples were very low, lower than the reference limits. Although the comparative analysis carried out pointed to an equivalent performance using technologies with different principles, the adequate evaluation of hematological analysis devices requires the development of certified reference materials, fundamental demand for the reliability of the differential quantification of leukocytes.
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Návrh vhodného etalonu délky pro nano-CT měřicí přístroj / Design of a suitable length standard for nanp-CT measuring device

Kožiol, Martin January 2020 (has links)
The diploma thesis deals with the design of three length standards, which will serve to ensure metrological traceability between Rigaku nano3DX, SIOS NMM-1, Zeiss UPMC Carat 850 and other devices located at ÚVSSR BUT and CEITEC Brno. The first part of the thesis focuses on the theoretical acquaintance with concepts closely related to the issue of ensuring metrological traceability. In addition, this section deals with computed tomography and the description of individual devices. The second part of the thesis is devoted to design, production process and testing of individual standards. The last part describes the ensuring the calibration of the smallest standard, the so-called Nano standard and the calculation of the uncertainty of measuring its calibrated length. At the end of the thesis, the outputs of these activities are evaluated.

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