Biofeedback is an important tool in the rehabilitation of several dysphagic conditions. This thesis presents an investigation into using bio-impedance as a technique for providing biofeedback of the swallowing sequence, specifically sequencing in the pharynx. The motivation behind this project was to find an alternative rehabilitation tool for detecting pharyngeal sequencing, as the current tool of pharyngeal manometry is invasive and non-portable. This investigation included the design and creation of a bio-impedance measuring device named the Guided Utility for Latency in Pharyngeal Sequencing (GULPS). This system was continued from a previous unpublished investigation at the University of Canterbury, where an initial prototype was designed and created. It was found that this pre-existing system had numerous faults in both its hardware and software, limiting the use of the device. Electrical impedance across the throat can be determined by applying a known constant amplitude current signal across the throat and recording the corresponding voltage. This impedance has been shown to change during a swallowing sequence due to a change in the structure of the throat. The principle used in this project was to investigate if two positions of impedance measurement could be used to determine the sequencing of the pharynx during a swallow. The design of the GULPS device was influenced by the pre-existing system and several prototypes were built to obtain a system capable of providing two channels of impedance measurement. Software was adapted from the pre-existing system to interface with this hardware to provide a system that could be attached to an external computer. Various electrode positions for the final device were trialled aimed at measuring two similar, but temporally separated, impedance waveforms. It was found that positioning the electrodes close to the approximate position of the pharynx with a 40 mm gap between channels allowed for two temporally separated channels to be produced with three distinct features: two peaks and one trough in each of the GULPS waveforms. The GULPS device with these electrode positions was trialled on three `healthy' subjects and one dysphagic subject. The three features could be identified in both impedance waveforms in all four subjects. To determine if the identified features related to the sequencing of the pharynx, the GULPS device was trialled alongside the current conventional method for detecting pharyngeal sequencing, pharyngeal manometry. The results from these trials revealed a potential relationship between the temporal separation of the second peaks found in the GULPS waveforms and the temporal separation of the pressure peaks from pharyngeal manometry. The GULPS device was trialled alongside pharyngeal manometry on one `healthy' and one dysphagic subject. A linear regression between peak-to-peak latencies between the two methods had an R squared value of 0.347 for the `healthy' subject and 0.241 for the dysphagic subject. However, these peaks were often difficult to detect, and could only be detected in 64% of swallows in the `healthy' subjects using the GULPS device in a standalone fashion and in 23% of swallows when used concurrently with manometry. As the current GULPS device is unable to produce the desired results in a consistent manner, no definitive conclusions can be drawn on the ability of using bio-impedance to measure the pharyngeal sequence. Notwithstanding, substantial progress has been made towards a device for reliable measurement of pharyngeal sequencing and, together with the clinical benefits to be gained, more than justify further research and development into GULPS for dysphagia rehabilitation.

Biological cells like any other material do conduct electricity. Though they come across as insulators, the resistance to the flow of current, i.e. impedance, could be used to characterize the cell itself. In this aspect, the impedance of cells can be a promising tool to investigate the state of the cell. A simple way of measuring the impedance would be a planar-microelectrode method. The cells are contained in culture medium while measurements are taken with micro-electrodes fabricated on top of a substrate. Since both the probe "tips" do not come in contact with the probed object, the impedance to be measured includes some components apart from that contributed by the cells. There have been publications reporting the usage of impedance of a cell to determine changes in the state of cells due to healing, drug candidate testing, functional genomic studies and so on. In this thesis, an effort has been made to measure the impedance of cells. Further, a component of the sensor, the passivation layer has been investigated for its contribution to the measured impedance in a quantitative manner. / Master of Science

Electrical bio-impedance can be considered as a physiological measurement of significant value in research and clinical applications. This is because certain structures of living organisms and the human body such as tissues and membranes are characterized by their specific impedance, which can be easily measured with existing technology. In addition, many body functions (physiological processes) involve changes in their ionic and electrolytic content and size, features that are followed by changes in their electrical characteristics indicated by their impedance values. The use of surface electrodes for measuring impedance in humans makes the method more attractive. Thus, during the 2nd half of the last century, impedance techniques have been developed to measure the blood flow in limbs, to form cross-sectional images of human body sections and to define body composition. The imaging techniques suffer from poor resolution due to the anisotropic electrical properties of the tissues. Epigastrography, based on determination of electrical impedance changes, is a simple, inexpensive, radiation free technique, which can be repeated many times without any trauma to the patient and is a valuable research tool. This work involves the generation, analysis and interpretation of epigastric electrical impedance signals. The signals recorded represent the epigastric impedance of a fasting volunteer before, during the oral intake of a liquid meal of typically 450 mL and for periods between 45 minutes to 2 hours post-prandially. The half emptying times (T50s) were calculated for a variety of test meals, and the statistically significant differences between the T50s were found for meals which varied in calorific content in a total of 7 studies with at least 9 subjects per study. Significant differences between T50s were found also when testing the same meal but under different conditions, namely, intravenous infusion of peptides (GLP-1, loxiglumide) or placebo (physiological saline) and the release in the gastric cavity of amino acids, free or bound with an orally taken gelatine capsule. However, the impedance T50s calculated were found to be considerably shorter than half emptying times presented in the literature using other techniques. Simultaneous application of scintigraphy confirmed that the T50s based on impedance were in comparison shorter. Similarly when experiments were carried out, simultaneously with the octanoic acid breath test and application of paracetamol absorption the same shorter, in comparison, values of T50s were obtained. The comparison with scintigraphy strengthened the suspicion that impedance values were being strongly influenced by the presence of gastric acid. Gastric acid studies undertaken for a number of conditions supported the considerable influence that gastric acid played. In vitro measurements of conductivity and pH of mixtures of test meals with gastric juice aspirations from subjects showed the acid influence. Finally, the physiology of the gastric mucosa from the resting state to secretion leads to the hypothesis that epigastric impedance is in the main controlled by the conductivity of the gastric content rather than by the volume of the meal content in the stomach and is supported by the laws of physics underlying the electrical impedance of a bulk object. In conclusion, both experimental and clinical results from the studies and investigations undertaken in this research convinced the author that the epigastric impedance reflects the conductivity and the acidity of the gastric content. Further by carrying out signal processing of the epigastric impedance signals employing fast Fourier transformation information was extracted about the gastric contractions in the range of 2.5 to 4.5 cycles per minute, confirming the usefulness of the technique in the study of gastric motility. In addition studies are necessary, to establish the validity of the results in the clinical environment and to answer conclusively the question "whether epigastric impedance can be developed as an external monitoring technique of gastric acidity and motility".

Impedance spectroscopy (IS) is a powerful and sophisticated tool to characterize intrinsic electrical properties of any materials and its interface, measuring the electric and transport properties of the materials, investigating the mechanism of electrochemical reaction etc. The fundamental principle of IS is the measurement of the impedance (equivalent to resistance in DC analysis) of the system under investigation over a wide frequency range. The IS study provides quantitative information about the conductance, the dielectric coefficient, the static properties of the interfaces like contact resistance, and its dynamic change due to adsorption or charge transfer phenomenon. Commercial Impedance analyzers that are available today are bulky and cannot be carried or deployed at remote locations for monitoring so easily, also such systems are expensive. Though IS concept is not new, standard Impedance analyzers are interfaced to the computer and require detailed analysis of the data by experts. Advancement in data conversion and signal processing is opening up opportunities for handheld smart devices. Hence it is felt that there is a need to develop a versatile low cost, portable (handheld) impedance analyzer instrument which can be used to characterize non linear materials like semiconductors, biological objects, and electrochemical samples. The instrument should be capable accepting test parameters using a touch screen based keypad and display test results on a Graphical LCD for quick analysis. Hence a standalone handheld instrument is designed to work independently without any PC control. The designed instrument consists of Digital Direct Synthesis (DDS) signal generator, a constant current source, Analog to digital convertor, Microcontroller to control frequency sweep parameters and acquire data, TFT Graphics LCD for displaying various plots, touch screen user interface to input sweep parameters and data storage section for offline analysis of obtained data. The instrument is designed to work on a battery or a regulated power supply. The instrument has options to display Nyquist plot, capacitance versus frequency plot, real and imaginary value of impedance versus frequency plot etc. Experimental investigations are conducted using this instrument on few passive components like resistor, inductor, capacitor and combinations. The instrument is also used to monitor the performance of polyimide based capacitive humidity sensor and its characteristics like sensitivity, linearity, repeatability and hysteresis. The measurement accuracy of the impedance varies from 0.7% to 4.67% depending on the impedance range. Bio impedance measurements are carried out on biological samples like Banana and the measured values are compared with the standard LCR meter. The bio impedance measurements are repeatable and comparable with the standard LCR meter readings and it is found to be within ±1% accuracy at the calibrated frequency. The instrument is also validated using industry standard Gauge R & R procedure to understand the repeatability and reproducibility of the instrument. The instrument exhibited good Repeatability and Reproducibility in current mode excitation than voltage mode excitation and Gauge R & R is 55% with P/T ratio is less than 2.5%.

ackground: The changes in body composition markers (weight, fat mass, lean mass, and BMI) over time can be associated with TB treatment outcome among HIV-infected patients. The aim of this study was to investigate whether changes in fat mass and lean mass were associated with the treatment response among patients with HIV infection and pulmonary tuberculosis. Materials and Methods: This was a prospective cohort study. Data from HIV-infected patients commencing TB therapy were analyzed. This included body weight measurement using bioimpedance equipment at baseline, one month, and two months after starting TB treatment. Results: The study was conducted in 125 patients, 17 patients (13.6%) died during treatment, of which 5 died during the first month of treatment, 4 during the second month and 8 after the second month. The group of patients with good response, increased their weight by 1.3 kg (p <0.001) at the end of the first month of TB treatment and 2.6 kg in the second month (p <0.001), and body fat increase was 1.2 Kg (p <0.001) and 2.3 kg (p <0.001), the first and second month respectively. The group of patients who died had lost 2.1 kg fat mass after the first month (p <0.001) and 3.7 kg in the second month (p <0.001). Conclusions: Our results show that the weight change during TB treatment (increased fat mass) helps us predict therapeutic response. Weight loss during the first month of starting therapy should be evaluated thoroughly to identify the probable cause of treatment failure. / Revisión por pares

Title: Comparison of body composition of soccer players according to their players' post Objectives: The main objective of this work is to determine the body composition of soccer players according to their post and to compare these data with the results of similar testing taken in foreign countries. Methods: 45 players participated in the testing in total. The machine of bioelectrical impedance BIA 2000 M was used for the detection of the body composition and the gained data were further proceeded in the programme NUTRI 4. The observed parameters were a percentage of body fat, an absolute amount of fat mass, fat-free and intracellular tissue. For the process of the statistic data (arithmetic average, BMI, standard deviation, tables and graphs) the programme Microsoft Excel 2007 was used. Results: The players of both Czech clubs have a typical body composition for top athletes. It was found out that the goalkeepers have the highest percentage of body fat out of all measured players. Defenders were proved to have the least percentage of body fat among all the measured players. Keywords: Soccer, player posts, body composition, bio impedance

La manipulation des membranes des cellules en suspension ou dans des tissus au moyen d’impulsions électriques constitue un sujet de recherche majeur au cœur du bio-électromagnétisme. A ce jour les impulsions de quelques microsecondes voire millisecondes ont été principalement étudiées. Elles n’affectent que la membrane plasmique des cellules. Les impulsions nanosecondes de fort niveau de champ (de l’ordre de quelques MV/m) ouvrent la voie vers la manipulation des organelles intra-cellulaires. En outre, elles constituent un nouvel outil pour l’étude des mécanismes de la perméabilisation. Les travaux de cette thèse ont été principalement consacrés aux effets des impulsions de 10 ns sur la membrane plasmique. Des protocoles expérimentaux permettant d’appliquer de façon reproductible et contrôlée les impulsions sur des objets vivants ont été définis. Des moyens de mesure (D-dot et B-dot) adaptés aux hautes tensions et hautes fréquences ont été développés et mis en œuvre, permettant un contrôle en temps réel des impulsions délivrées.Différentes approches ont permis de mettre en évidence la perméabilisation des cellules par des impulsions de 10 ns. Ces techniques regroupent notamment le suivi de bio-impédance dans les tissus et l’internalisation de molécules cytotoxiques non perméantes dans des cellules en suspension et in vivo sur des tumeurs. Les expériences conduites ont permis de mettre en évidence la plus grande efficacité des basses fréquences de répétition dans la perméabilisation d’un tissu végétal (la pomme de terre). De plus l’influence de la conductivité du milieu extracellulaire sur le niveau de perméabilisation a été investiguée. Ces expériences ont permis de mettre en évidence l’importance de la dynamique d’établissement et de relaxation de la différence de potentiel transmembranaire dans l’efficacité de la perméabilisation.Enfin un microscope CARS (Coherent Anti-stokes Raman Scattering) plein-champ a été développé. Sa conception a été pensée en vue de l’étude des effets des impulsions ultra-courtes sur le vivant à l’échelle moléculaire. A ce jour il permet d’obtenir des images de cellules en CARS en 3 ns. / New devices for the controlled application of nanosecond electrical pulses and the detection of their effects on cells. New findings and hypotheses on the parameters controlling the electropermeabilization of biological cells.Abstract:Manipulation of the membranes of cells in suspension or in tissues with electrical pulses is a major research topic in bio-electromagnetism. Until recently the effects of pulses of a few microseconds or milliseconds have mainly been studied. Such pulses only affect the cell plasma membrane. Pulses of a few nanoseconds with high field strength (of the order of a few MV /m) might lead to intracellular organelles manipulation. In addition, they represent a new tool to study the mechanisms of permeabilization.This thesis was mainly devoted to the effects of pulses of 10 ns on the plasma membrane. Experimental protocols to apply controlled and reproducible pulses on living objects have been defined. Measurement means (D-dot and B-dot) adapted to high voltages and high frequencies have been developed and implemented thus allowing for accurate and real-time monitoring of the pulses applied on the biological samples.Different approaches have been used to highlight the permeabilization of biological cells by pulses of 10 ns. The techniques used include the monitoring of bio-impedance in tissues and the internalization of non-permeant cytotoxic molecules in cells in suspension and in vivo in tumors. The conducted experiments allowed to demonstrate the high efficiency of low repetition rates in permeabilizing potato tissue. The influence of the conductivity of the extracellular medium on the efficiency of the permeabilization was also investigated. These experiments highlighted the important role played by the dynamic of the establishment and relaxation of the transmembrane potential difference.Finally a wide-field CARS microscope (Coherent Anti-Stokes Raman Scattering) was developed. It has been designed to study the effects of ultra-short pulses on biological cells at the molecular level. It already enables to obtain images of cells in 3 ns.

The points of the Master Thesis have become the research of prevalence in overweight and obesity in adolescent age group, writing out and application of interventional activity programme focused on reduction of overweight and obesity. In theoretical part of the Master Thesis, there was given the characteristic of overweighting and obesity, followed by their causations and complications, and as well as research methods and medical treatment. Two hundred and eight adolescents were undergone the research. The experimental and comparison groups were found upon of those adolescents. The experimental group, thirty adolescents, had undergone through twelve-week-long-programme. Contents of this programme were mainly power-yoga and yoga exercises. After the attendance of this programme; body weights, BMIs, waist circumferences were decreased. As well the sum of skin folds and the sum of body fat were decreased. Also psychosocial relations were amended. Given hypothesis have been verified by the correct presumptions about the effect of interventional activity programme. Enlisted data were statistically processed and interpreted.

Biopsy is a standard practice in the diagnosis and treatment of many cancers. Despite its integral role in cancer diagnosis, in some instances, the biopsy tool facilitates metastasis by transferring cancerous cells attached to its exterior into the healthy tissue or the blood circulation during its retraction from the tumor. These few cancer cells can then serve as seeds for the malignant tumor to grow in the healthy tissue. Cauterization using extreme heat or cold can destroy cells in the region and minimize the chance of seeding but this can be an inexact process that increases damage to otherwise healthy tissue and prolongs healing time following a biopsy procedure. In our laboratory, we have developed the concept of a new smart biopsy tool that can reduce the chance of cancer cell dissemination during a biopsy. This tool improves on the conventional biopsy needle by introducing an impedance sensor on the biopsy tool which is housed in a sliding sheath. Due to the significant difference in the electrical conductivity of the tumor and the healthy tissue, the sensor is able to distinguish between the two and locate the exact tumor interface. The protective sheath placed around the instrumented biopsy tool and above the interface isolates the healthy tissue and prevents or at least minimizes the transfer of tumor cells. Delivering an RF dose through the sheath can kill any malignant cells that might be lurking around the interface. This thesis, in particular, will concentrate on the development of the design, fabrication and calibration of the impedance sensor and its integration with the biopsy tool. The impedance sensor essentially consists of conductive electrodes sandwiched between insulating layers. They are built on thin-film polymer, Polyimide, using conventional microfabrication techniques. These sensors are further calibrated to estimate the cell constant. Once calibrated, these probes are used to measure the conductivity of porcine tissues, and in-house prepared agar phantoms. / Master of Science

Cette thèse porte sur la conception et la réalisation de micros capteurs à électrodes interdigitées pour la caractérisation des milieux biologiques dans la gamme de fréquences : 100 kHz - 10 MHz. L'objectif principal de ce travail est l’optimisation géométrique de la structure d’un capteur à électrodes interdigitées afin d’élargir la plage fréquentielle de mesure en réduisant les effets de polarisation. Le premier chapitre synthétise les données fondamentales relatives au comportement électrique des tissus biologiques ainsi que leurs propriétés électriques notamment en basses fréquences. Le deuxième chapitre concerne une approche théorique pour l’optimisation du capteur pour élargir la bande de fréquence utile de mesure ; ce chapitre recommande également une nouvelle méthode pour déterminer les paramètres de la double couche à la surface en contact entre les électrodes et le milieu biologique. Dans le troisième chapitre nous proposons une modélisation tridimensionnelle du système d’électrodes chargé par un modèle du milieu biologique sous le logiciel ConventorWare®. Les résultats de simulation sont discutés. Les résultats obtenus nous permettent d’évaluer l'influence des paramètres géométriques de la structure interdigitée du capteur ainsi que les propriétés diélectriques du milieu sur l’impédance bioélectrique. Les facteurs d’influence en fonction de la fréquence sont ainsi maîtrisés lors de la conception d’u capteur interdigité destiné à la mesure de bioimpédance. Dans le quatrième chapitre, les dispositifs ainsi que la conception et la fabrication des composants développés au cours de cette thèse sont décrits. Dans le dernier chapitre, les mesures expérimentales effectuées avec de très faibles volumes de différentes solutions (solutions étalons, sang humain) par cinq micros capteurs à électrodes interdigitées. Les mesures sur les échantillons ainsi que la validation des théories d’optimisation ont été élaborées et discutées. Enfin nous avons comparé nos résultats à des valeurs publiées dans la littérature et nous avons justifié expérimentalement la théorie d’optimisation développée. / This thesis focuses on the design and realization of interdigitated sensors for the electrical characterization of the biological medium within the frequency range: 100 kHz - 10 MHz. The main objective of this thesis is to optimize the geometry of the sensor structure according to the specificities of the interdigitated electrodes structure. This optimization leads to widen the measurement frequency range by reducing the effects of polarization at low frequency. The first chapter synthesizes the basics and fundamentals relative to the electric behavior of biological tissues as well as to their electric properties. The second chapter concerns a theoretical approach for the optimization of the sensor to widen the useful frequency band of measurement; this chapter also presents a new method to determine the parameters of the double layer at the contact interface between the electrodes and the biological medium. A three-dimensional modelling of the system, the electrodes being loaded with a biological medium, is implemented using ConventorWare® software and the results discussed in the third chapter. The results obtained allow us to evaluate the influence of the geometrical parameters of the interdigitated structure of the sensor as well as the dielectric properties of the medium on the bioelectric impedance. In the fourth chapter, the devices developed during this thesis are described. The design and the manufacturing of components are presented. The last chapter deals with the experimental measurements obtained with very small volumes of the different solutions (standard solutions, human blood) using five micro sensors that we built in the laboratory. The measurements as well as the validation of the theoretical approach are discussed. Finally we have compared our results with published values in the literature and validated our experimental and theoretical approaches developed in this work.