Low resolution pharyngeal manometry is an invasive diagnostic method that has recently been used as a biofeedback device for swallowing rehabilitation. The University of Canterbury Rose Centre uses pharyngeal manometry to diagnose and rehabilitate subjects who suffer from pharyngeal mis-sequencing. Pharyngeal mis-sequencing occurs when pressure is applied simultaneously throughout the pharynx rather than sequentially. Rehabilitation can only be performed in clinic due to the need for specialized equipment and trained staff, and the invasiveness of the test limits the time that can be spent training. As an alternative method to measure the pharyngeal pressure sequence, bioimpedance has been investigated by a previous University of Canterbury Master’s student. A prototype was developed that measured bioimpedance in two locations as a proxy for pharyngeal pressure sequence. The prototype device named GULPS (Guided Utility for Latency in Pharyngeal Swallowing), measured a change in impedance during swallowing. However, the features of this waveform were inconsistent and were not present during every swallow. The frequency of the current that passes through tissue affects its path through the tissue, therefore impacting the measured impedance. To improve the consistency of the impedance measurement, the effect of current injection frequency was investigated. A modular-hardware system was created from the original design to allow testing of different injection frequencies. The hardware was further developed by replacing the method of generating the constant amplitude current injection signal. The improvement to the design resulted in a differently-shaped waveform to that of the previous prototype, including a new feature. This feature is a single peak that occurred in both channels and was reproduced in every swallow. Experimentation showed that the features were not obviously frequency dependent. The separation between the peaks of the two impedance channels was compared with the separation between the two pressure peaks recorded during simultaneous pharyngeal manometry but there was no significant correlation between the two measures of peak-peak separations. Two alternative hardware/signal conditioning changes were trialled: electrical isolation of each channel and a subtraction method, which aims to remove the effect of the changing impedance between the two electrode channels. Electrical isolation of the two channels had no effect on the impedance waveforms. However, the subtraction method produced a different output and requires further investigation as the output was inconsistent. Bluetooth communication was integrated into the GULPS hardware, and a corresponding Android Application (App) was written. The developed App was successful in displaying the impedance measurement output and adds greater user flexibility, allowing the user to interface with the bioimpedance measurement hardware from their tablet or phone. With no measured significant correlation between GULPS and pharyngeal manometry, further research needs to be performed to better relate the features measured by GULPS to those seen during pharyngeal manometry. Until this can be achieved, the GULPS device cannot replace pharyngeal manometry for biofeedback-based rehabilitation of pharyngeal mis-sequencing.

Schlucken ist ein lebensnotwendiger Prozess, dessen Diagnose und Therapie eine enorme Herausforderung bedeutet. Die Erkennung und Beurteilung von Schlucken und Schluckstörungen erfordert den Einsatz von technisch aufwendigen Verfahren, wie Videofluoroskopie (VFSS) und fiberoptisch-endoskopische Schluckuntersuchung (FEES), die eine hohe Belastung für die Patienten darstellen. Beide Verfahren werden als Goldstandard in der Diagnostik von Schluckstörungen eingesetzt. Die Durchführung obliegt in der Regel ärztlichem Personal. Darüber hinaus erfordert die Auswertung des Bildmaterials der Diagnostik eine ausreichend hohe Erfahrung. In der Therapie findet neben den klassischen Therapiemethoden, wie z.B. diätetische Modifikationen und Schluckmanöver, auch zunehmend die funktionelle Elektrostimulation Anwendung. Ziel der vorliegenden Dissertationsschrift ist die Evaluation eines im Verbundprojekt BigDysPro entwickelten Bioimpedanz (BI)- und Elektromyographie (EMG)-Messsystems. Es wurde geprüft, ob sich das BI- und EMG-Messsystem eignet, sowohl in der Diagnostik als auch in der Therapie als eigenständiges Messsystem und im Rahmen einer Schluckneuroprothese eingesetzt zu werden. In verschiedenen Studien wurden gesunde Probanden für die Überprüfung der Reproduzierbarkeit (Intra-und Interrater-Reliabilität), der Unterscheidbarkeit von Schluck- und Kopfbewegungen und der Beeinflussung der Biosignale (BI, EMG) durch verschiedene Faktoren (Geschlecht der Probanden, Leitfähigkeit, Konsistenz und Menge der Nahrung) untersucht. Durch zusätzliche Untersuchungen mit Patienten wurde einerseits der Einfluss der Elektrodenart geprüft. Andererseits wurden parallel zur BI- und EMG-Messung auch endoskopische (FEES) und radiologische Schluckuntersuchungen (VFSS) durchgeführt, um die Korrelation der Biosignale mit der Bewegung anatomischer Strukturen (VFSS) und mit der Schluckqualität (FEES) zu prüfen. Es wurden 31 gesunde Probanden mit 1819 Schlucken und 60 Patienten mit 715 Schlucken untersucht. Die Messkurven zeigten einen typischen, reproduzierbaren Signalverlauf, der mit anatomischen und funktionellen Änderungen während der pharyngalen Schluckphase in der VFSS korrelierte (r > 0,7). Aus dem Bioimpedanzsignal konnten Merkmale extrahiert werden, die mit physiologischen Merkmalen eines Schluckes, wie verzögerter laryngealer Verschluss und Kehlkopfhebung, korrelierten und eine Einschätzung der Schluckqualität in Übereinstimmung mit der FEES ermöglichten. In den Signalverläufen der Biosignale konnten signifikante Unterschiede zwischen Schluck- und Kopfbewegungen und den Nahrungsmengen und -konsistenzen nachgewiesen werden. Im Gegensatz zur Nahrungsmenge und -konsistenz zeigte die Leitfähigkeit der zu schluckenden Nahrung, das Geschlecht der Probanden und die Art der Elektroden keinen signifikanten Einfluss auf die Messsignale. Mit den Ergebnissen der Evaluation konnte gezeigt werden, dass mit dem BI- und EMG-Messsystem ein neuartiges und nicht-invasives Verfahren zur Verfügung steht, das eine reproduzierbare Darstellung der pharyngalen Schluckphase und ihrer Veränderungen ermöglicht. Daraus ergeben sich vielseitige Einsatzmöglichkeiten in der Diagnostik, z.B. Langzeitmessung zur Schluckfrequenz und Einschätzung der Schluckqualität, und in der Therapie, z.B. der Einsatz in einer Schluckneuroprothese oder als Biofeedback zur Darstellung des Schluckes, von Schluckstörungen. / Swallowing is a vital process. Its diagnosis and therapy represent enourmous medical challenges. The detection and assessment of swallows and swallowing disorders require elaborate techniques such as videofluoroscopy (VFSS) and fiberoptic endoscopic evaluation of swallowing (FEES), which entail a high burden for the patient. Both methods are currently used as a goldstandard in the diagnosis and therapy of swallowing disorders. The measurements must, in general, be performed and evaluated by experienced medical personnel. In therapy, dietary modifications and swallowing maneuvers are common methods. But also functional electrical stimulation (FES) is increasingly used. The goal of this doctoral thesis was the evaluation of the combined bioimpedance (BI) and electromyography (EMG) measurement system that was developed within the research project BigDysPro. In particular, it should be examined whether the system can be used in the diagnosis and therapy of swallowing disorders as an independent measurement system and in the context of a swallowing neuroprosthesis. Several studies were conducted with healthy subjects to assess the reproducibility of the measurements, the distinction of swallowing from head movements, and the influence of different factors (i.e. the subject's gender as well as amount, consistency, and conductivity of the food) on the bioimpedance and electromyography. In additional experiments with patients, the influence of the electrode type, i.e. surface vs. needle electrodes, was examined. Furthermore, patients were examined with FEES and VFSS in parallel measurements with the new system. Thereby, the correlation of the BI and EMG signals with movements of anatomical structures (VFSS) and with the swallowing quality (FEES) was assessed. In these studies, 31 healthy subjects with 1819 swallows and 60 patients with 715 swallows were examined. The measured signals show a typical, reproducable run of the curve, that correlates with the anatomical and functional alterations observed by videofluoroscopy during the pharyngeal phase of swallowing (r > 0, 7). From the curve of the bioimpedance, features were extracted to assess the quality of swallowing. These features were demonstrated to correlate with physiological phenomena, such as delayed laryngeal closure and larynx elevation. Therefore, they were used to assess the swallow quality in accordance with fiberoptic endoscopic examination of swallowing. Significant differences were found in the measurement signals of swallows and head movements, as well as in the signals from different food amounts and consistencies. In contrast, the conductivity of the food, the gender of the subjects, and the type of electrodes had no significant effect on the curve of the bioimpedance and the electromyography. From the results of the evaluation, it is concluded that the combined bioimpedance and electromyography measurement system represents a novel, non-invasive tool. It enables the reproducible assessment of the pharyngeal phase of swallowing. In diagnosis, the system might be used, e.g., in long-time measurements for the assessment of swallowing frequency and quality. In therapy, the method can be implemented in a swallowing neuroprosthesis or might be used in a biofeedback system.

The objective of the proposed research is to design an experimental setup to assess the ability of impedance measurements to characterize mouse embryonic stem cell (ESC) and embryoid body (EB) growth and differentiation. Existing quality assurance measurements used to stage the growth and differentiation of embryoid bodies are labor intensive and most often destructive to the cells, thus present methods are typically valid for a single time point. Bioimpedance measurements are non-invasive and non-destructive, presenting an alternative approach to this challenge. These measurements can be done continuously for real-time measurements on the changes in embryoid body growth and differentiation. A system capable of making bioimpedance measurements of ESC and EB suspensions was designed along with a biocompatible test device to hold the cells and Ag-AgCl electrodes. The system uses a lock-in amplifier to record the magnitude and phase changes of the ESC and EB suspensions when a 1 Vpp signal sweeping frequencies from 100 Hz to 100 kHz is applied. The system performance was validated with a test case of 1 mL of 0.1 M KCl. Then experiments with cell culture media, ESCs, and EBs were performed, with varying concentrations of cells and EBs. Experimental results for single ESC suspensions showed promise in detecting a difference in cell concentration between 2 million and 4 million cells in 0.5 mL of media. Results for four day old EBs were ambiguous, and we conclude that a different experimental set up is required due to EB settling during experimentation.

Bioimpedance spectroscopy has shown potential as a method for characterising biological tissue with the use of a tetrapolar electrode configuration. Brown et al. (2000) demonstrated that the configuration is capable of distinguishing between normal squamous epithelium and Cervical Intra-epithelial Neoplasia (CIN). However little has been done to identify the volumes of tissue that contribute to the measured impedance. Brown et al. employed a probe with a single tetrapolar electrode set thus analysing single points of tissue. The probe was required to be moved in order to "sample" other areas of tissue. This method provides no spatial information of the lesion boundaries. The overall objective of this research was to design and construct an impedance mapping system (IMS) for objective virtual biopsy of lesions by bioimpedance spectroscopy (BIS). Initially freshly excised cervical tissue was to be tested however as the study progressed this proved problematic and bovine blood was chosen as a suitable substitute. Specific aims were to; - .Investigate the spatial sensitivity distribution of the tetrapolar electrode configuration via finite element analysis (FEA). - Design a novel front end multiplexing system and multi-electrode array for mapping the impedance of the tissue of interest. - .Experimentally confirm the efficacy of the approach to identify regions of different impedances and their boundaries using bioimpedance mapping. The present study used finite element analysis (FEA) to investigate the spatial variation in sensitivity of the tetrapolar electrode configuration and identify which volumes of tissue were included in the measured impedance. An impedance mapping device was also designed and constructed utilising the tetrapolar electrode configuration in an expanded array of 25 electrodes. This array allowed the surface of an area of tissue to be mapped and lesion boundaries identified in an objective manner. FEA was also used to model lesions in healthy tissue and the sensitivity fields associated with the tetrapolar configuration. The FEA indicated that anomalous results would be obtained when a lesion was located between a drive and measurement electrode pair. In this case the lesion resulted in an increase in impedance with respect to the impedance of healthy tissue, whereas a lesion should result in a decrease in measured impedance relative to that of healthy tissue. The anomaly was found to produce false negative results for small lesions up to 0.4 mm and even a lesion with radius of approximately 0.75 mm could be undetected as the measured impedance spectrum for such a lesion is similar to that of healthy tissue. Modelling also provided insight into the sensitivity fields for an electrode array and its efficacy in accurately measuring the surface impedance of tissue and lesions of interest. The impedance mapping system (IMS) developed used an array of 25 (5x5) electrodes. The array allows 64 individual tetrapolar measurements to be obtained at 16 locations, providing an impedance map of 49 mm2 on the surface of a tissue sample. Multiple measurements at each location reduce the chance of anomalous results since these can be identified and excluded. Software was developed to display the measured impedance maps and regions of different impedance were easily identified Testing of the IMS using bovine blood showed separation of the measured impedance for a range of haematocrit between 0 - 80%. Introduced volumes of red blood cells (RBC) or clots (to mimic lesions) to the plasma (haematocrit 0%) were also clearly identified using the IMS. It was seen that measurements made at the boundary of 2 different haematocrits (ie 2 volumes of different impedance) resulted in an anomalous result as indicated by the FEA modelling. However it was demonstrated that these anomalies can be used to objectively identify the introduced RBC (lesion) boundaries. A more efficient electrode stepping sequence was also developed taking advantage of the reciprocal nature of the tetrapolar electrode configuration. This development allows for the electrode array to be doubled in size using the same components, and to sample twice the surface area in the same time taken using the initially developed system. In summary, an impedance mapping system has been modelled, designed and developed for tissue characterisation by bioimpedance measurements. The technique has been shown experimentally to be able to detect regions of differ- ent impedance and is in agreement with the finite element analysis performed. Further development of the IMS will allow progressive monitoring of suspect lesions in-vivo and better identification of their spatial distribution for biopsy.

TDCS is a form of non-invasive neurostimulation that is comprised of injection of current via strategically placed scalp electrodes into targeted areas of the brain. TDCS has shown therapeutic benefit for numerous clinical applications. This technique has not however been widely adopted due to high variability of response to the stimulation. Current state of the art methods for optimizing tDCS are based on FEM models that generally model tissue as isotropic and homogeneous and do not take into account inter subject variability of head tissue electrical properties. We therefore develop an in-vivo method of measuring and analyzing bioimpedance spectroscopy measurements of the head to estimate change to tDCS dose in neural tissues for different subjects. Finite element simulations are implemented on a realistic MRI derived head model. 5\% random Gaussian noise is added. Experimental bioimpedance measurements are taken of the heads of 8 subjects. We simulate sensitivity distribution and impedance for a variety of 2 and 4 electrode configurations over a wide frequency range. We also extract Cole parameters and implement PCA on simulated and experimental impedance. We demonstrate that the Cole model of the head can be accurately approximated by the sum in series of Cole systems of each tissue. Comparison of Cole parameters from various simulated electrode configurations show statistical differences (paired t test $p<.05$). PCA shows that close to 100\% of the variance between two impedance spectra is described along a single principal component. Variation described by the second principal component increases as a function of increasing inter electrode gap which may be related to changes in dose. FEM and experimentally derived Cole parameters show different trends for various electrode configurations, good agreement is however shown for the PCA results. The outcome of this research may lead to a higher tDCS efficacy by improving standardization and control of stimulation by relation of dose and bioimpedance spectra characteristics.

Introdução: A associação entre tuberculose (TB) e desnutrição é bem reconhecida: a TB pode levar à desnutrição e a desnutrição pode predispor à TB. Levando-se em consideração o risco de mortalidade devido à desnutrição em pacientes com TB e as inúmeras limitações dos estudos realizados até hoje, é necessário realizar uma avaliação nutricional mais completa e precoce com o objetivo de identificar os indivíduos em risco nutricional. Objetivos: Avaliar o estado nutricional dos pacientes hospitalizados com TB, coinfectados ou não pelo vírus da imunodeficiência humana (HIV). Métodos: Estudo de prevalência com coleta de dados prospectiva. Foram incluídos pacientes com diagnóstico confirmado de TB. Foram utilizados os seguintes métodos para avaliação nutricional: índice de massa corporal (IMC), dobras cutâneas, bioimpedância, circunferência do braço (CB), circunferência muscular do braço (CMB), questionário de frequência alimentar, ferramenta de triagem de desnutrição (MST), avaliação subjetiva global (ASG) e dosagens de hemoglobina, transferrina, proteína C reativa, albumina e linfócitos. Resultados: Foram incluídos 92 pacientes no estudo. Considerando o IMC, 37% dos pacientes avaliados apresentavam critérios para risco nutricional. O percentual de gordura corporal foi baixo em 31,5% dos pacientes. Além disso, mais da metade dos indivíduos estudados apresentou critérios para desnutrição conforme a CB, CMB, dobra cutânea tricipital, ASG, MST ou parâmetros laboratoriais. Com relação aos nutrientes da dieta, em pacientes HIV positivos a ingestão de selênio foi significativamente menor do que nos pacientes HIV negativos. Também foram encontradas correlações positivas entre o IMC e a quantidade de zinco e magnésio da dieta. Conclusões: Identificamos uma prevalência elevada de desnutrição em pacientes com TB pulmonar internados em um hospital terciário, independente do método utilizado para avaliação do estado nutricional. / Introduction: The association between tuberculosis (TB) and malnutrition is well recognized: TB can lead to malnutrition and malnutrition can predispose to TB. Taking into account the risk of mortality due to malnutrition in patients with TB and the numerous limitations of the studies conducted to date, it is necessary to conduct a more thorough and early nutritional assessment in order to identify individuals at nutritional risk. Objectives: To assess the nutritional status of hospitalized patients with TB, co-infected or not by the human immunodeficiency virus (HIV). Methods: Prevalence study with prospective data collection. Patients with confirmed diagnosis of TB. The following methods of nutritional assessment were used: body mass index (BMI), skinfold thickness, bioelectrical impedance, arm circumference (AC), arm muscle circumference (AMC), food frequency questionnaire, malnutrition screening tool (MST), subjective global assessment (SGA) and serum levels of hemoglobin, transferrin, C-reactive protein, albumin and lymphocytes. Results: We included 92 patients in the study. Considering the BMI, 37% of the patients met the criteria for nutritional risk. The body fat percentage was low in 31.5% of patients. In addition, more than half of the subjects met criteria for malnutrition according to AC, AMC, triceps skinfold thickness, SGA, MST or laboratory parameters. Regarding the components of diet, selenium intake among HIV-positive patients was significantly lower than in HIV-negative patients. It was also found positive correlations between the BMI and the amount of dietary zinc and magnesium. Conclusions: We identified a high prevalence of malnutrition in patients with pulmonary TB admitted in a tertiary hospital, regardless of the method used to assess nutritional status.

No intervalo de valores de frequência de poucos kHz até 1 MHz, nomeado às vezes como região de dispersão ?, as estruturas das células são o principal determinante da impedância do tecido. Esse é o fundamento básico da Espectroscopia da Bioimpedância Elétrica - EBE, a qual tem importância significativa como ferramenta de diagnóstico do câncer de colo no útero - CCU. A EBE consiste na medição de impedância elétrica do tecido cervical para diferentes valores de frequência. A diferença do comportamento no valor da impedância na frequência entre o tecido normal e o cancerígeno é usada para detectar o nível de neoplasia. Um bloco importante do Sistema EBE é o bloco gerador de sinal, o qual está composto principalmente de: a) Oscilador Controlado Numericamente - NCO, b) Conversor Digital - Analógico - DAC e c) Fonte de Corrente Controlada por Tensão - VCCS. O Objetivo do presente trabalho foi o projeto dos blocos principais do Gerador de Sinal para aplicação da Espectroscopia da Bioimpedância Elétrica na Detecção do Câncer no colo do Útero. O Gerador de Sinal é composto de: Oscilador Controlado Numericamente baseado no algoritmo de CORDIC, Conversor Digital - Analógico de 10 bits e Fonte de Corrente Controlada por Tensão. É apresentado o projeto do Oscilador Controlado Numericamente (NCO) de 10 bits baseado na arquitetura iterativa do CORDIC e otimizado em termos da área. O NCO foi implementado na Tecnologia CMOS do Processo da TSMC 180 nm por meio do FREE MINI@SIC IMEC-TSMC 2015. As especificações do projeto foram obtidas dos requerimentos da aplicação da Espectroscopia da Bioimpedância Elétrica - EBE na detecção do Câncer no Colo do Útero - CCU. A arquitetura proposta é composta fundamentalmente de: seletor de frequência de 5 bits, gerador do valor angular, bloco de pré-rotação, unidade aritmética do CORDIC, Unidade de Controle e tabela de busca da referência para arco-tangente. A área do núcleo para este componente foi de 133µmx133µm, ou seja, 0,017689 mm². Foi configurado para gerar 32 valores de frequência de sinais sinusoidais no intervalo de valores de frequência de 100 Hz até 1 MHz com um erro máximo de 0,00623% entre os valores de frequência obtidos da simulação e os resultados experimentais. O Conversor Digital - Analógico foi projetado no nível do esquemático numa arquitetura Current-Steering Segmentada 6-4 com valores de DNL<0,1 LSB e INL<0,2 LSB obtidos na análise de corners. O circuito VCCS foi projetado, simulado e fabricado em Tecnologia CMOS da TSMC 130 nm com polarização de 1,3 V. A Fonte de Corrente de Howland proposta foi baseada no amplificador operacional auto polarizado complementar de cascode dobrado (SB-CFC). De acordo com os requerimentos do padrão internacional IEC:60601-1 o valor pico da corrente sinusoidal foi ajustado em 10 µA. De acordo com aplicação da EBE para a CCD, as especificações do SB-CFC-AO foram calculadas para obter uma corrente sinusoidal na faixa de frequência de 100 Hz até 1 MHz com impedância de saída maior do que 1 MOhm a 1 MHz de frequência. Foram executadas simulações post-layout e os principais resultados foram: 10±0,0035 µA para a amplitude na corrente de saída na faixa de frequência especificada com 5 kOhm de resistência de carga, valores de impedância de saída maiores do 1,6 MOhm a 1 MHz; variações na amplitude da corrente de saída menores do que 0,4% para impedância de carga de 10 Ohm até 5 kOhm. O resultado experimental em termos de não-linearidade apresentou o máximo de 2% da plena escala. De acordo com os resultados obtidos, o desempenho do VCCS é adequado para aplicações da EBE na CCD. / In the frequency range of a few kHz to 1 MHz, sometimes referred to as the ? dispersion region, cell structures are the main determinant of tissue impedance. That is a basic fundamental of Electrical Bio-Impedance Spectroscopy - EBS, which has a significant importance as a diagnostic tool for Cervical Cancer Detection - CCD. EBS consists in the measurements of Electrical Impedance of cervical tissue at different values of frequency. The difference of behavior of impedance value in the frequency of normal tissue and cancerous tissue is used to detect the level of neoplasia. An important block of EBS System is the block signal generator, which is mainly composed of: a) Numerically Controlled Oscillator - NCO, b) Digital to Analog Converter - DAC and c) Voltage Controlled Current Source - VCCS. The aims of this work was to design the main blocks of a Signal Generator for Electrical Bio-Impedance Spectroscopy applied to Cervical Cancer Detection. The signal generator is composed by: CORDIC-Based Numerically Controlled Oscillator, 10-bits Digital-to-Analog Converter and Voltage Controlled Current Source - VCCS. A 10-bit Numerically Controlled Oscillator (NCO) based on the iterative architecture of COordinate Rotation DIgital Computer (CORDIC) optimized in terms of area is presented. The NCO was implemented in a TSMC CMOS 180 nm technology process on the FREE MINI@SIC IMEC-TSMC. The design specifications were obtained from the requirements for application of Electrical Bio-Impedance Spectroscopy (EBS) to Cervical Cancer Detection (CCD). The proposed architecture is basically composed by: 5-bit frequency selector, angle generator, pre-rotator block, CORDIC Arithmetic Unit, Control Unit and lookup table for arctangent reference. The area of this IC for the CORE circuit was 133µm X 133µm, i.e. 0,017689 mm². It was configured in order to generate 32 different frequencies for output sinusoidal signals in the frequency range of 100Hz up to 1MHz with maximum error of 0,00623% in frequency values obtained of comparison of theoretical and experimental results. The 10 bits DAC was implemented in a 6-to-4 Current Steering Segmented architecture with DNL<0,1 LSB and INL<0,2LSB obtained from corners analysis. The circuit VCCS was designed, simulated and fabricated in TSMC 130 nm CMOS technology at 1.3V power supply. The proposed Howland Current Source is based on Self-Biased Complementary Folded Cascode (SB-CFC) Operational Amplifier (OA). Complying with the requirements for medical electrical equipment of international standard ABNT-NBR-IEC-60601-1 the sinusoidal current peak amplitude was settled at 10 µA. In accordance with the requirements of the EBS for CCD, the specifications for the SB-CFC-OA were calculated to meet the 100 Hz to 1 MHz frequency range for the sinusoidal output current and the output impedance higher than 1 MOhm at 1 MHz frequency. Post-layout simulations were run and the main results were: 10 ± 0.0335 µA for the output current peak amplitude over the specified frequency range and with 5 kOhm load impedance; values above 1.6 MOhm output impedance @ 1 MHz; nominal current amplitude variations lower than 0.4% for load impedances in the range of 10 Ohm up to 5 kOhm. And the experimental result for maximum non-linearity was 2% of full scale. From these results, the performance of the VCCS is adequate for EBS-CCD applications.

Orientador: Jacqueline Pontes Monteiro / Banca: Daniela Saes Sartorelli / Banca: Carlos Alberto Scrideli / Banca: Maria Rita Marques de Oliveira / Banca: Maria Jacira Silva Simães / Resumo: As crianças com câncer necessitam manter o crescimento linear e o ganho de peso para uma melhor evolução clínica. Assim, o tratamento da criança com câncer deve garantir não só sua sobrevivência, mas proporcionar crescimento e desenvolvimento adequados. A avaliação nutricional é utilizada para reconhecer o paciente com maior facilidade de desenvolver a má nutrição garantindo assim um planejamento nutricional adequado. O objetivo do presente estudo foi avaliar o estado nutricional de crianças antes, durante e após o tratamento quimioterápico. Foram avaliadas 14 crianças com câncer, com idade entre 5 a 15 anos, divididas em dois grupos: Grupo Tumores Sólidos e Grupo Tumores Hematológicos. Estas foram avaliadas através dos dados de ingestão alimentar, antropometria, análise por Impedância Bioelétrica (BIA) e por Diluição Isotópica. Os resultados encontrados demonstram que os pacientes apresentaram um aumento de peso, estatura, índice de massa corporal, circunferência do quadril, da cintura e do braço, da prega cutânea subescapular, assim como o aumento da massa gorda pela técnica de diluição isotópica durante o tratamento quimioterápico, no Grupo Tumores Hematológicos. No Grupo Tumores Sólidos as crianças apresentaram uma diminuição da massa magra, quando analisado pela impedância bioelétrica. Houve uma correlação positiva entre a prega cutânea tricipital e a massa gorda obtida através da BIA e pela Diluição Isotópica. A circunferência muscular do braço também se correlacionou com a massa magra estimada pela BIA e pela Diluição Isotópica. Não houve mudança na ingestão energética e de macronutrientes nos três momentos da pesquisa. Esses resultados demonstram que os pacientes com tumores hematológicos apresentaram aumento de peso, estatura e de massa gorda, fato este não ocorrido no Grupo Tumores Sólidos. / Abstract: Children with cancer need to maintain growth and weight gain to a better clinic evolution. So, the treatment of children with cancer must not only guarantee the survival but also adequate growth and development. The nutritional assessment is useful to recognize the patient who is more accessible to develop malnutrition leading to an adequate nutritional plan. The aim of this study was to assess the nutritional status in children before, during and after chemotherapy treatment. In this study, 14 children with cancer were evaluated ranging from 5-15 years old devided into two groups: Hematologic Tumor Group and Solid Tumor Group. They were evaluated through dietary intake, anthropometry, bioimpedance analysis (BIA) and isotopic dilution. The results show that the patients increase weight, stature, body mass index, hip, waist and arm circumferences, subscapular skinfold thickness, as well as an increase in fat-mass with isotopic dilution technique during the chemotherapy treatment, in the Hematologic Tumors Group. In the Solid Tumor Group the children showed a reduction in fat free mass when assessed by bioelectric impedance. There was a positive correlation between triceps skinfold thickness and fat-mass with BIA and Isotopic Dilution technique. The arm muscle circumference correlated with the fatfree- mass estimated by the BIA and Isotopic Dilution. There was no change in energetic intake and macronutrients at the three moments of the research. These results demonstrate that patients with hematologic tumors had an increase in body weight, stature and fat-mass, which was not observed in Solid Tumors Group. The good correlation between anthropometry and isotopic dilution technique and BIA show its applicability in clinical practice. / Doutor

Determination of body composition or amount and decomposition of body fat belongs to the basic clinical examination of an obese patient. But methods used to determine the amount of fat in obese population are often innacurate. And it's adipose tissue and its measurable parameters which can provide us range of information for the further process of the reductive treatment. The main goal of this work is to evaluate the physiological aspects of body composition measurement in several areas: (I) To determine whether the values of body fat measured by most commonly used methods are comparable to those measured by method DEXA. (II) To determine whether the values of the amount of body fat measured by different methods vary depending on the amount of BMI and adipose tissue in the body and assess whether the available bioimpendance methods can measure the functional state of body fat. (III) To assess the resting energy expenditure in relation to body composition and physical activity. (IV) To determine whether the body composition will affect the resulting reduction after excercise program for women with overweight and obesity. (V) To verify whether changes in the values of BOHB (Beta Hydroxybutyrate) after physical activity could be the predictor of weight losses and changes of body composition. Based on...

Introdução: A associação entre tuberculose (TB) e desnutrição é bem reconhecida: a TB pode levar à desnutrição e a desnutrição pode predispor à TB. Levando-se em consideração o risco de mortalidade devido à desnutrição em pacientes com TB e as inúmeras limitações dos estudos realizados até hoje, é necessário realizar uma avaliação nutricional mais completa e precoce com o objetivo de identificar os indivíduos em risco nutricional. Objetivos: Avaliar o estado nutricional dos pacientes hospitalizados com TB, coinfectados ou não pelo vírus da imunodeficiência humana (HIV). Métodos: Estudo de prevalência com coleta de dados prospectiva. Foram incluídos pacientes com diagnóstico confirmado de TB. Foram utilizados os seguintes métodos para avaliação nutricional: índice de massa corporal (IMC), dobras cutâneas, bioimpedância, circunferência do braço (CB), circunferência muscular do braço (CMB), questionário de frequência alimentar, ferramenta de triagem de desnutrição (MST), avaliação subjetiva global (ASG) e dosagens de hemoglobina, transferrina, proteína C reativa, albumina e linfócitos. Resultados: Foram incluídos 92 pacientes no estudo. Considerando o IMC, 37% dos pacientes avaliados apresentavam critérios para risco nutricional. O percentual de gordura corporal foi baixo em 31,5% dos pacientes. Além disso, mais da metade dos indivíduos estudados apresentou critérios para desnutrição conforme a CB, CMB, dobra cutânea tricipital, ASG, MST ou parâmetros laboratoriais. Com relação aos nutrientes da dieta, em pacientes HIV positivos a ingestão de selênio foi significativamente menor do que nos pacientes HIV negativos. Também foram encontradas correlações positivas entre o IMC e a quantidade de zinco e magnésio da dieta. Conclusões: Identificamos uma prevalência elevada de desnutrição em pacientes com TB pulmonar internados em um hospital terciário, independente do método utilizado para avaliação do estado nutricional. / Introduction: The association between tuberculosis (TB) and malnutrition is well recognized: TB can lead to malnutrition and malnutrition can predispose to TB. Taking into account the risk of mortality due to malnutrition in patients with TB and the numerous limitations of the studies conducted to date, it is necessary to conduct a more thorough and early nutritional assessment in order to identify individuals at nutritional risk. Objectives: To assess the nutritional status of hospitalized patients with TB, co-infected or not by the human immunodeficiency virus (HIV). Methods: Prevalence study with prospective data collection. Patients with confirmed diagnosis of TB. The following methods of nutritional assessment were used: body mass index (BMI), skinfold thickness, bioelectrical impedance, arm circumference (AC), arm muscle circumference (AMC), food frequency questionnaire, malnutrition screening tool (MST), subjective global assessment (SGA) and serum levels of hemoglobin, transferrin, C-reactive protein, albumin and lymphocytes. Results: We included 92 patients in the study. Considering the BMI, 37% of the patients met the criteria for nutritional risk. The body fat percentage was low in 31.5% of patients. In addition, more than half of the subjects met criteria for malnutrition according to AC, AMC, triceps skinfold thickness, SGA, MST or laboratory parameters. Regarding the components of diet, selenium intake among HIV-positive patients was significantly lower than in HIV-negative patients. It was also found positive correlations between the BMI and the amount of dietary zinc and magnesium. Conclusions: We identified a high prevalence of malnutrition in patients with pulmonary TB admitted in a tertiary hospital, regardless of the method used to assess nutritional status.