Title: Evaluation of body composition analysis using anthropometric measurements and methods based on bioimpedance Aims: The main goal of this study is to analyze correlations of the data from bioimpedance with direct anthropometric measurements using statistical data analysis taking into consideration that the latter data is recognized as a gold standard. Methods: The sample of 42 men and 20 women was evaluated using standard anthropometric techniques. In addition, the dimensions, which are necessary to establish the weight of segments in upper and lower arms. The obtained data was firstly evaluated using a universal software ANTROPO. The both samples were concurrently investigated using the bioimpedance methods and the relationships between the aforementioned data and data from InBody was evaluated by three independent statistical methods such as substantive significance (Cohen's d), two-parameter linear regression and robust Passing- Bablok regression. Results: The results obtained enable to conclude that (with the exception of body height and BMI) the remaining parameters do not sufficiently correlate when using anthropometric measurements and data from InBody. As the relatively low number of participants may result in certain misrepresentation of the results, particularly in women, the...

Bioimpedance spectroscopy is very useful in biomedical field as a safe and non-invasive technique. A stable and safe excitation current below than 0.5 mA for load impedances changing from 100 Ω to 10 kΩ in the full β-dispersion range from kHz up to 1 MHz is a big challenge for the design of the current source addressed by this thesis. For a good stability and high accuracy, the source should have a high output impedance. Different current source types in “current-mode approach” and “voltage-mode approach” were investigated and compared for usability in bioimpedance measurement systems. The “voltage-mode approach” with grounded load was proven to be more suitable and stable for biomedical measurements. Thereby the Tietze and the Howland circuit in dual configuration with negative feedback have shown the lowest error of the output current and the highest output impedance, where the improved Howland circuit in dual configuration with negative feedback is preferred because it has a simple structure, high accuracy and good stability. We suggest to improve the stability of the Howland circuit in dual configuration with negative feedback by introducing compensated operational amplifiers and to reduce stray capacitances at higher frequencies by adding gain compensation capacitor. We reach thereby an accuracy of 0.5% at low frequency and 0.9% at 1 MHz. With the realized accuracy of the designed voltage controlled current source, one decisive prerequisite for portable bioimpedance measurement system is achieved. In order to select the appropriate excitation signals for short measurement time, a comparative study of signals and their parameters was carried out. It leads to the selection of binary chirp signal as a suitable excitation signal due to its short measurement time about 100 μs, low crest factor lower than 2.8 and an energy efficiency higher than 54% in a very noisy signal. Simulation results show that the designed enhanced Howland current source excited by the binary chirp signal has low error and flatness in the whole range. / Die Bioimpedanzspektroskopie gewinnt aufgrund ihrer besonderen Eigenschaften als nicht-invasive, schonende Messmethode zunehmend an Bedeutung im biomedizinischen Bereich. Dabei ergeben sich besondere erausforderungen für den Entwurf der Stromquelle zur Realisierung eines stabilen und sicheren Anregungsstroms. Gefordert ist eine hohe Genauigkeit bis zu einem Maximalstrom von 0.5 mA in einem Frequenzbereich, der der β-Dispersion entspricht, von wenigen kHz bis hin zu 1 MHz. Die Stabilität muss bei variablen Lastimpedanzen im Bereich von 100 Ω bis 10 kΩ gewährleistet sein. Dafür muss die Stromquelle eine hohe Ausgangsimpedanz aufweisen. Diese Arbeit fokussiert auf den Entwurf von spannungsgesteuerten Stromquellen. Verschiedene Arten von Stromquellen wurden untersucht und verglichen. Der "Voltage-Modus-Ansatz" mit Masse-referenzierter Last hat sich als besser geeignet und stabiler für biomedizinische Messungen erwiesen. Die Tietze-Schaltung und diese Howland-Schaltung zeigen dabei die niedrigsten Fehler des Ausgangsstroms und die höchste Ausgangsimpedanz. Im direkten Vergleich besitzt die verbesserte Howland-Schaltung doch eine einfachere Struktur, höhere Genauigkeit und bessere Stabilität und wird daher gegenüber der Tietze-Schaltung bevorzugt. Um weitere Stabilitätsverbesserungen bei der Howland-Schaltung zu erreichen, werden zwei Maβnahmen vorgeschlagen. Zum einen werden kompensierte Operationsverstärker eingeführt und zum anderen wird der Einfluss von Streukapazitäten bei hohen Frequenzen minimiert indem die Verstärkung mit Kondensatoren kompensiert wird. Durch diese Maβnahmen wird eine Genauigkeit von 0.5% bei niedrigen Frequenzen und 0.9% bei 1 MHz ermöglicht. Mit dem neuen Entwurf der spannungsgesteuerten Stromquelle ist ein entscheidender Meilenstein für die Realisierung tragbarer Messsysteme der Bioimpedanz erreicht. Um eine kurze Messzeit zu realisieren wurde eine vergleichende Studie von Anregungssignalen und deren Signalparameter durchgeführt. Die Ergebnisse zeigen, dass binäre Chirp-Signale aufgrund der reduzierten Messzeit, des niedrigen Crest-Faktors unter 2.8 und hohe Energieeffizienz von mehr als 54% bei hohem Rauschlevel besonders geeignet sind. Simulationsergebnisse zeigen, dass die entwickelte Howland-Stromquelle zusammen mit einem binären Mehrfrequenzsignal den geringsten Amplitudenfehler im gesamten Frequenzbereich realisiert.

A pancreatite crônica alcoólica (PCA) tem o álcool como seu principal fator etiológico, a relação entre ingestão de álcool e estado nutricional é complexa e as características nutricionais dos portadores de PCA são pouco conhecidas. Neste trabalho, foram avaliados três grupos de pacientes do sexo masculino, o primeiro (A) com 20 pacientes com PCA, o segundo (B) com 12 etlistas crônicos não pancreatopatas e não hepatopatas e o terceiro (C) com 16 indivíduos não etlistas, não pancreatopatas e não hepatopatas. Para analisar os três grupos utilizaram-se a avaliação antropométrica, a quantificação da ingestão alcoólica, quando existente, o inquérito dietético obtido por Recordatório de 24 horas, a composição corpórea, obtida por bioimpedância elétrica, exames séricos relacionados à avaliação hepática e pancreática, dosagem de vitaminas e de sais minerais, além de marcadores inflamatórios, como proteína C reativa, seroamiloide A e leptina, além de exames de imagem, como ultrassonografia abdominal e/ou tomografia computadorizada de abdômen. A PCA (Grupo A) não se associou à queda da ingestão dietética, porém houve redução da massa magra, evidenciando desnutrição protéica; os etilistas sem pancreatite (Grupo B) apresentaram menor massa magra em relação aos pacientes do grupo C e foi possível demonstrar que a composição corpórea e o perfil inflamatório são distintos e relevantes, não apenas na PCA (Grupo A), mas também nos etilistas sem lesão pancreática (Grupo B), que também devem ser melhor estudados e acompanhados ao longo do seu curso clínico. Em síntese, encontraram-se evidências de subnutrição e aberrações metabólicas tanto nos casos de alcoolismo com lesão pancreática quanto nos etilistas aparentemente sem lesão pancreática ou hepática. Achado até o momento não relatado pela literatura / Alcoholic pancreatitis has alcohol as the primary etiologic factor. The relationship between alcohol intake and nutritional status is complex and the nutritional characteristics of patients with this disease are unknown. In this study, we evaluated three groups of male patients, one (A) with 20 patients with alcoholic pancreatitis, another (B) with 12 alcoholics without pancreatic or liver disease and the last (C) with 16 non - alcoholics , free from any systemic disease or organ insufficiency. To analyze the three groups, we used anthropometric assessment, quantification of alcohol intake, dietary recall, body composition estimated by bioimpedance analysis, biochemical tests related to liver and pancreatic function, dosage of vitamins and minerals, inflammatory markers namely C-reactive protein, leptin and serum amyloid A, in addition to imaging studies such as abdominal ultrasonography and computed tomography of the abdomen whenever required. Group A was not associated with decrease in food intake, but there was a reduction in lean body mass, indicating undernutrition. Alcoholics without pancreatitis (group B) also showed lower lean mass compared to patients in group C, demonstring that changes in body composition and inflammatory status are distinct and relevant also in alcoholics without pancreatic injury (Group B). They should be better studied and monitored throughout their clinical course. In synthesis evidence of undernutrition and metabolic aberrations were demonstrated in both alcoholism with pancreatic damage and in nominally healthy alcoholics, a finding not hitherto reported in the literature

Este trabalho consiste no projeto e implementação em CMOS de um circuito integrado digital para geração de sinais, denominado Oscilador Controlado Numericamente. O circuito será aplicado em um sistema de Espectroscopia por Bioimpedância Elétrica, utilizado como método para detecção precoce de câncer do colo do útero. Durante o trabalho, realizou-se o estudo dos requisitos do sistema de espectroscopia e as especificações dos tipos de sinais a serem gerados. Levantou-se, na bibliografia, algumas técnicas de codificação em linguagem de hardware para otimização do projeto nos quesitos área, potência dissipada e frequência máxima de funcionamento. Para implementar o circuito, também se pesquisou o fluxo de projeto de circuitos digitais, focando as etapas de codificação em linguagem de descrição de hardware Verilog e os resultados de síntese lógica e de layout. Foram avaliadas duas arquiteturas, empregando-se algumas das técnicas de codificação levantadas durante o estudo bibliográfico. Estas arquiteturas foram implementadas, verificadas em plataforma programável, sintetizadas e mapeadas em portas lógicas no processo TSMC 180 nm, onde foram comparados os resultados de área e dissipação de potência. Observou-se, nos resultados de síntese lógica, redução de área de 78% e redução de 83% na dissipação de potência total no circuito em que se aplicou uma das técnicas de otimização em comparação com o circuito implementado sem otimização, utilizando uma arquitetura CORDIC do tipo unrolled. A arquitetura com menor área utilizada - 0,017 mm2 - foi escolhida para fabricação em processo mapeado. Após fabricação e encapsulamento do circuito, o chip foi montado em uma placa de testes desenvolvida para avaliar os resultados qualitativos. Os resultados dos testes foram analisados e comparados aos obtidos em simulação, comprovando-se o funcionamento do circuito. Observou-se uma variação máxima de 0,00623% entre o valor da frequência do sinal de saída obtido nas simulações e o do circuito fabricado. / The aim of this work is the design of a digital integrated circuit for signal generation called Numerically Controlled Oscillator, designed in 180 nm CMOS technology. The application target is for Electrical Bioimpedance Spectroscopy system, and can be used as a method for early detection of cervical cancer. Throughout the work, the spectroscopy system requirements and specifications of the types of signals to be generated were studied. Furthermore, the research of some coding techniques in hardware language for design optimization in terms of area, power consumption and frequency operation was conducted looking into the bibliography. The digital design flow was studied focusing on the Verilog hardware description language and the results of logic synthesis and layout, in order to implement the circuit. Reviews of two architectures have been made, using some of the encoding techniques that have been raised during the bibliographical study. These architectures have been implemented, verified on programmable platform, synthesized and mapped to standard cells in TSMC 180 nm process, which compared the area and total power consumption of results. Based on the results of logic synthesis, a 78% area reduction and 83% power consumption reduction were obtained on the implemented circuit with encoding techniques for optimization in comparison with the another circuit using a CORDIC unrolled architecture. The architecture with smaller area - 0.017 mm2 - was chosen for implementation in the mapped process. After the circuit fabrication and packaging, the chip was mounted on an evaluation board designed to evaluate the functionality. The test results were analyzed and compared with the simulation results, showing that the circuit works as expected. The output signals were compared between theoretical and experimental results, showing a maximum deviation of 0.00623%.

Ce travail de thèse traite de la caractérisation par spectroscopie d'impédance d'échantillons biologiques de très faibles dimensions. Les phénomènes de polarisation, classiques en spectroscopie d'impédance, créent une contrainte et augmentent l'erreur de mesure en basses fréquences. L'objectif principal de cette thèse est l'optimisation géométrique de la structure d'un capteur à électrodes interdigitées afin d'élargir la bande de fréquence utile. Le premier chapitre synthétise les données fondamentales relatives au comportement électrique des tissus biologiques ainsi que leurs propriétés électriques. Un état de l'art des techniques fondamentales de mesure d'impédance basées sur les électrodes micrométriques est aussi décrit. Le deuxième chapitre concerne une approche théorique pour l'optimisation du capteur. Cette optimisation sert à élargir la bande de fréquence utile de mesure. Elle consiste à choisir un rapport optimum de distance inter-électrodes sur largeur d'électrode. Une modélisation tridimensionnelle du système d'électrodes chargé par un milieu biologiquea été simulée sous ConventorWare©. Les résultats de cette simulation sont discutés. Le troisième chapitre traite de la conception et de la réalisation des biocapteurs. Les dispositifs technologiques développés sont décrits. La conception et la fabrication des composants sont présentées. Dans le dernier chapitre, une campagne de mesure sur des micro-volumes de fluides (solutions étalons, sang humain) est réalisée. Les mesures sont effectuées à l'aide de cinq micros capteurs à électrodes interdigitées. Les mesures réalisées sur des échantillons (solution étalons, sang humain) ainsi que la validation des dispositifs sont discutées. Les résultats obtenus sont comparés à des valeurs publiées dans la littérature et la théorie d'optimisation développée est validée et justifiée expérimentalement / The characterization by impedance spectroscopy of biological micro samples is one of the objectives of this thesis. The well known polarization phenomena at low frequency is a constraint that increases the measurement error. The main objective of this thesis is to optimize the geometric structure of an interdigitated electrode sensor in order to obtain confident experimental results in an extended useful frequency band without a significant influence of the polarization effect. The first chapter synthesizes fundamental data on the electrical behavior of biological tissues and their electrical properties. A state of the art techniques of the fundamental impedance measurement based on micrometric electrodes is also presented. The second chapter developps a theoretical approach for optimization of the biosensor. This optimization is used to expand the usable measurement. Indeed, it leads to determine the optimum distance between electrodes versus electrode width. A 3D modeling of the electrode system loaded by a biological medium was simulated using ConventorWare and the results are discussed. In the third chapter, the devices developed in this work are described. Design and manufacture of the biosensor components are described. In the last chapter, measurements on microvolumes of fluids (standard solutions, human blood) using five micros sensors with interdigitated electrodes are presented and discussed. Finally we compare these results to published values in the literature and the optimization theory is experimentally validated

Thanks to pioneering scientists and clinicians, prosthetic devices that are controlled by intra-cortical electrodes recording one's 'thoughts' are a reality today, and no longer merely in the realm of science fiction. However, widespread clinical use of implanted electrodes is hampered by a lack of reliability in chronic recordings, independent of the type of electrodes used. The dominant hypothesis has been that astroglial scar electrically impedes the electrodes. However, recent studies suggest that the impedance changes associated with the astroglial scar are not high enough to interfere significantly impair neural recordings. Furthermore, there is a time delay between when scar electrically stabilizes and when neural recordings fail (typically >1 month lag), suggesting that scar, per se, does not cause chronic recording unreliability. In this study, an alternative hypothesis was tested in a rat model, namely, that chronic inflammation surrounding microelectrodes causes a local neurodegenerative state. Chronic inflammation was varied in three ways: 1) stab wound control, 2) age-matched control, and 3) inter-shank spacing of a multishank electrode. The results of this study suggest that chronic inflammation, as indicated by activated microglia and reactive astrocytes, is correlated with local neurodegeneration, marked by neuron cell death and dendritic loss. Surprisingly, axonal pathology in the form of hyperphosphorylation of the protein Tau (the hallmark of many tauopathies, including Alzheimer's Disease) was also observed in the immediate vicinity of microelectrodes implanted for 16 weeks. Additionally, work is presented on a fast, non-invasive method to monitor the astrocytic response to intra-cortical electrodes using electrical impedance spectroscopy. This work provides a non-invasive monitoring tool for inflammation, albeit an indirect one, and fills a gap which has slowed the development of strategies to control the inflammatory tissue response surrounding microelectrodes and thereby improve the reliability of chronic neural recordings. The results of these experiments have significance for the field of neuroengineering, because a more accurate understanding of why recordings fail is integral to engineering reliable solutions for integrating brain tissue with microelectrode arrays.

Este trabalho consiste no projeto e implementação em CMOS de um circuito integrado digital para geração de sinais, denominado Oscilador Controlado Numericamente. O circuito será aplicado em um sistema de Espectroscopia por Bioimpedância Elétrica, utilizado como método para detecção precoce de câncer do colo do útero. Durante o trabalho, realizou-se o estudo dos requisitos do sistema de espectroscopia e as especificações dos tipos de sinais a serem gerados. Levantou-se, na bibliografia, algumas técnicas de codificação em linguagem de hardware para otimização do projeto nos quesitos área, potência dissipada e frequência máxima de funcionamento. Para implementar o circuito, também se pesquisou o fluxo de projeto de circuitos digitais, focando as etapas de codificação em linguagem de descrição de hardware Verilog e os resultados de síntese lógica e de layout. Foram avaliadas duas arquiteturas, empregando-se algumas das técnicas de codificação levantadas durante o estudo bibliográfico. Estas arquiteturas foram implementadas, verificadas em plataforma programável, sintetizadas e mapeadas em portas lógicas no processo TSMC 180 nm, onde foram comparados os resultados de área e dissipação de potência. Observou-se, nos resultados de síntese lógica, redução de área de 78% e redução de 83% na dissipação de potência total no circuito em que se aplicou uma das técnicas de otimização em comparação com o circuito implementado sem otimização, utilizando uma arquitetura CORDIC do tipo unrolled. A arquitetura com menor área utilizada - 0,017 mm2 - foi escolhida para fabricação em processo mapeado. Após fabricação e encapsulamento do circuito, o chip foi montado em uma placa de testes desenvolvida para avaliar os resultados qualitativos. Os resultados dos testes foram analisados e comparados aos obtidos em simulação, comprovando-se o funcionamento do circuito. Observou-se uma variação máxima de 0,00623% entre o valor da frequência do sinal de saída obtido nas simulações e o do circuito fabricado. / The aim of this work is the design of a digital integrated circuit for signal generation called Numerically Controlled Oscillator, designed in 180 nm CMOS technology. The application target is for Electrical Bioimpedance Spectroscopy system, and can be used as a method for early detection of cervical cancer. Throughout the work, the spectroscopy system requirements and specifications of the types of signals to be generated were studied. Furthermore, the research of some coding techniques in hardware language for design optimization in terms of area, power consumption and frequency operation was conducted looking into the bibliography. The digital design flow was studied focusing on the Verilog hardware description language and the results of logic synthesis and layout, in order to implement the circuit. Reviews of two architectures have been made, using some of the encoding techniques that have been raised during the bibliographical study. These architectures have been implemented, verified on programmable platform, synthesized and mapped to standard cells in TSMC 180 nm process, which compared the area and total power consumption of results. Based on the results of logic synthesis, a 78% area reduction and 83% power consumption reduction were obtained on the implemented circuit with encoding techniques for optimization in comparison with the another circuit using a CORDIC unrolled architecture. The architecture with smaller area - 0.017 mm2 - was chosen for implementation in the mapped process. After the circuit fabrication and packaging, the chip was mounted on an evaluation board designed to evaluate the functionality. The test results were analyzed and compared with the simulation results, showing that the circuit works as expected. The output signals were compared between theoretical and experimental results, showing a maximum deviation of 0.00623%.

A pancreatite crônica alcoólica (PCA) tem o álcool como seu principal fator etiológico, a relação entre ingestão de álcool e estado nutricional é complexa e as características nutricionais dos portadores de PCA são pouco conhecidas. Neste trabalho, foram avaliados três grupos de pacientes do sexo masculino, o primeiro (A) com 20 pacientes com PCA, o segundo (B) com 12 etlistas crônicos não pancreatopatas e não hepatopatas e o terceiro (C) com 16 indivíduos não etlistas, não pancreatopatas e não hepatopatas. Para analisar os três grupos utilizaram-se a avaliação antropométrica, a quantificação da ingestão alcoólica, quando existente, o inquérito dietético obtido por Recordatório de 24 horas, a composição corpórea, obtida por bioimpedância elétrica, exames séricos relacionados à avaliação hepática e pancreática, dosagem de vitaminas e de sais minerais, além de marcadores inflamatórios, como proteína C reativa, seroamiloide A e leptina, além de exames de imagem, como ultrassonografia abdominal e/ou tomografia computadorizada de abdômen. A PCA (Grupo A) não se associou à queda da ingestão dietética, porém houve redução da massa magra, evidenciando desnutrição protéica; os etilistas sem pancreatite (Grupo B) apresentaram menor massa magra em relação aos pacientes do grupo C e foi possível demonstrar que a composição corpórea e o perfil inflamatório são distintos e relevantes, não apenas na PCA (Grupo A), mas também nos etilistas sem lesão pancreática (Grupo B), que também devem ser melhor estudados e acompanhados ao longo do seu curso clínico. Em síntese, encontraram-se evidências de subnutrição e aberrações metabólicas tanto nos casos de alcoolismo com lesão pancreática quanto nos etilistas aparentemente sem lesão pancreática ou hepática. Achado até o momento não relatado pela literatura / Alcoholic pancreatitis has alcohol as the primary etiologic factor. The relationship between alcohol intake and nutritional status is complex and the nutritional characteristics of patients with this disease are unknown. In this study, we evaluated three groups of male patients, one (A) with 20 patients with alcoholic pancreatitis, another (B) with 12 alcoholics without pancreatic or liver disease and the last (C) with 16 non - alcoholics , free from any systemic disease or organ insufficiency. To analyze the three groups, we used anthropometric assessment, quantification of alcohol intake, dietary recall, body composition estimated by bioimpedance analysis, biochemical tests related to liver and pancreatic function, dosage of vitamins and minerals, inflammatory markers namely C-reactive protein, leptin and serum amyloid A, in addition to imaging studies such as abdominal ultrasonography and computed tomography of the abdomen whenever required. Group A was not associated with decrease in food intake, but there was a reduction in lean body mass, indicating undernutrition. Alcoholics without pancreatitis (group B) also showed lower lean mass compared to patients in group C, demonstring that changes in body composition and inflammatory status are distinct and relevant also in alcoholics without pancreatic injury (Group B). They should be better studied and monitored throughout their clinical course. In synthesis evidence of undernutrition and metabolic aberrations were demonstrated in both alcoholism with pancreatic damage and in nominally healthy alcoholics, a finding not hitherto reported in the literature

No description available.

Title: Body Composition and Motor Performance of Roma Children in the Most District Background: The Roma way of life, or rather the values they live up to, is different from the values and way of life of the majority population. This results in a lower life expectancy of the Roma and a worse social position in Czech society, even in total social exclusion. Since the individual's lifestyle evolves from childhood on, we focused on assessing the lifestyle using several parameters of body composition and motor performance of Roma children in socially excluded Roma localities Aims: The aim of this thesis is to find out the influence of the lifestyle of Roma children living in socially excluded Roma localities in the Most district on their body composition and motor performance. The second goal is to compare the body composition and motor performance of the children from majority population and socially excluded children from the Most district with the Czech children population standards. Methods: In total 733 children 7-15 years of age participated in the study, of which 448 were from majority population of the Most district (221 girls and 227 boys) and 285 children were from socially excluded Roma localities in the Most district (124 girls and 161 boys). Bioelectric impedance analysis (BIA 2000 M...