- Graduated in Electrical Engineering in 1995 at the State University of Santa Catarina and PhD in Medical Physics at t... moreGraduated in Electrical Engineering in 1995 at the State University of Santa Catarina and PhD in Medical Physics at the University of Sheffield. Awarded by Fulbright at Dartmouth College and visiting researcher in the University of Ljubljana. Titular Professor at UDESC since 2004, lecturing electronic instrumentation, sensors and transducers, introduction on biomedical engineering and coordinating research groups in biomedical engineering and electrical bioimpedance. Senior IEEE member since 2020. Reviewer of more than 12 international journals. Secretary of the ISEBI. International lectures in renowned Universities, such as Uruguay, Ljubljana, Sheffield, Copenhagen and Mexico. Areas of research interest are focused on electrical bioimpedance and bioinstrumentation, Biosensor and e-Health. Edited international books, such as “Bioimpedance in Biomedical Applications and Research” and “Medicine-Based Informatics and Engineering” by Springer.edit
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A maioria das técnicas de diagnóstico por imagem para detecção de fraturas ósseas utiliza equipamentos que emitem radiação, que pode ser prejudicial à saúde humana, mesmo em pequenas doses. Sem dúvida, estudos são necessários e novas... more
A maioria das técnicas de diagnóstico por imagem para detecção de fraturas ósseas utiliza equipamentos que emitem radiação, que pode ser prejudicial à saúde humana, mesmo em pequenas doses. Sem dúvida, estudos são necessários e novas técnicas que busquem a redução dessas exposições ao raio-x. O objetivo deste artigo é desenvolver um fantoma biológico 3D e investigar a sensibilidade de detecção de ossos, inteiro e fraturado, por meio da espectroscopia de impedância elétrica. Além disso, são investigados os efeitos das diferentes posições dos eletrodos na sensibilidade da técnica de medição. As medições foram realizadas por um espectroscópio de impedância comercial da Zurich Instruments (modelo HF2IS) na faixa de frequência de 1 kHz a 1 MHz. Quatro eletrodos circulares (modelo MELCTEC) foram usados para conectar o fantoma ao HF2IS. O HF2IS foi inicialmente calibrado medindo um resistor de 100 Ω e 1% de precisão. Vetores de calibração de magnitude e fase foram calculados e então usad...
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I International Workshop on Applied Biosensing (WBIO 2024) will provide an excellent international forum for aims to bring together researchers and practitioners from academia and industry to focus on Biosensing platforms from all sort of... more
I International Workshop on Applied Biosensing (WBIO 2024) will provide an excellent international forum for aims to bring together researchers and practitioners from academia and industry to focus on Biosensing platforms from all sort of technologies focusing on advancements, recent systems and techniques in the broad field of Biosensing. Original research papers, state-of-the-art reviews are invited for publication in all areas of biosensing involving Electrical, Biomedical and Electronics Engineering, Medical Physics, Computing Science, and related applications related to chemistry, environment, food quality, biology and medical diagnosis.
Research Interests: Bioinformatics, Microfluidics, Data Analysis, Spectroscopy, Digital Signal Processing, and 9 moreElectronics and biomedical engineering, Wearable sensors, Sensor Technology, Nanobiotechnology and Biosensors, Implantable Sensors, Point-of-care diagnostics, Bioelectronics, Medical Diagnosis, and Electrical Bioimpedance
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Human cell cultures are powerful laboratory tools for biological models of diseases, drug development, and tissue engineering. However, the success of biological experiments often depends on real-time monitoring of the culture state.... more
Human cell cultures are powerful laboratory tools for biological models of diseases, drug development, and tissue engineering. However, the success of biological experiments often depends on real-time monitoring of the culture state. Conventional culture evaluation methods consist of end-point laborious techniques, not capable of real-time operation and not suitable for three-dimensional cultures. Electrical Impedance Tomography (EIT) is a non-invasive imaging technique with high potential to be used in cell culture monitoring due to its biocompatibility, non-invasiveness, high temporal resolution, compact hardware, automatic operation, and high throughput. This review approaches the different hardware strategies for cell culture EIT that are presented in the literature, discussing the main components of the measurement system: excitation circuit, voltage/current sensing, switching stage, signal specifications, electrode configurations, measurement protocols, and calibration strategies. The different approaches are qualitatively discussed and compared, and design guidelines are proposed.
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In the recent decades the bioimpedance has been used in many areas of medicine. The technological advance of electronics has enabled the increase of bioimpedance applica- tions. Measuring biological tissues is a hard work, which leads to... more
In the recent decades the bioimpedance has been used in many areas of medicine. The technological advance of electronics has enabled the increase of bioimpedance applica- tions. Measuring biological tissues is a hard work, which leads to the need of continuous research based on better methods and equipments for diagnosis. Many electronics manufacturers have helped the biomedical area through the development of new electronic components and equipment. The objective of this work is to adapt the impedance meter AD5933 for bioim- pedance measurements. Two Analog Front-End (AFE) circuits were built with different Voltage Controlled Current Source (VCCS) topologies, which are a load-in-the-loop and a mir- rored modified Howland current sources. Circuits were im- plemented and both two and four electrode measurements in the frequency range of 5 to 100 kHz were performed. Results showed that both front-end circuits are suitable to be used with the AD5933 at lower frequencies. Also, it might be a low-cost alternative for electrical bioimpedance applications.
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Continuous glucose monitoring is essential to reduce the damages caused by diabetes and for choosing the right treatment approach. In most cases, non-invasive glucose measurement devices generate their results through statistical tools... more
Continuous glucose monitoring is essential to reduce the damages caused by diabetes and for choosing the right treatment approach. In most cases, non-invasive glucose measurement devices generate their results through statistical tools (e.g., artificial neural networks) with an error that increases the further away from the training sample the measurement is. An analytical model would contain only propagated errors. Impedance measurements of lactate ringer’s solutions with egg albumin containing different concentrations of sugar were performed to validate the model proposed for measuring glycemia in human blood using the electrical bioimpedance meter AD5933. The curve fitting showed errors lower than 1.5%. Chemical phenomena, such as reduced sugar, fructosamine and solvation, might explain the behaviors observed in the experiments. The results suggest that the relaxation coefficient has significant changes with the increase of sugar in the solutions. The findings encourage future research with bovine blood for a more realistic analytical model.
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Over the recent years, Internet of Things have been used to monitor biosignals in a large scale. Large scale demands the use of many biosensors and a complex control system, which may results in high cost technology. This article proposes... more
Over the recent years, Internet of Things have been used to monitor biosignals in a large scale. Large scale demands the use of many biosensors and a complex control system, which may results in high cost technology. This article proposes a simple fall detection system targeting the elderly population at low cost. A prototype based on the Arduino Uno, accelerator and gyroscope was implemented and fixed in a individual’s torso. Five types of movement were analyzed (walking, sitting, running, and falling). Data were transferred to a mobile phone using the HC-06 Bluetooth transmission module. The final proposed prototype was about $18.00 and have the advantage of detecting falls automatically. Measurements showed that a fall can be detected by either using the gyroscope or the accelerometer. The findings from this article mighty be useful when working on a multi-parameter device which uses intelligent algorithms to control health and fall among the elderly. With these, algorithms, it is expected to improve the fall detection system so that it also provides the individual's location and history of movements that precede a possible fall.
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Abstract This chapter is based on the design of current source according to the previous information based mainly on the type of sample under study, number of electrodes, frequency range, and the required measuring voltage across the... more
Abstract This chapter is based on the design of current source according to the previous information based mainly on the type of sample under study, number of electrodes, frequency range, and the required measuring voltage across the load. Different types of current source structures are discussed as well as the measuring system that is also correlated to the choice of its implementation. Limiting factors should be understood for better designing a reliable current source for a wideband bioimpedance application. A summary of the main stages when implementing a basic bioimpedance hardware for electrical impedance spectroscopy applications is brought to the attention of the readers.
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The dielectric properties of dry and wet palmar skin of the hand are presented here. The knowledge of these properties especially at frequencies below 100 Hz is important for dosimetry purposes. However, there are few empirical data... more
The dielectric properties of dry and wet palmar skin of the hand are presented here. The knowledge of these properties especially at frequencies below 100 Hz is important for dosimetry purposes. However, there are few empirical data available at these frequencies and they are contradictory. Electrodes made of carbon fibers were fabricated. They are concentric with an inner electrode and an outer ring one. Impedance measurements were collected from 1 Hz to 1 MHz on wet and dry palmar skin of the hand, then permittivity and conductivity were calculated. Permittivity values ranged from 1,912 to 6.6 × 106 and from 2,358 to 34.4 × 106 for dry and wet skin, respectively. Conductivity values ranged from 0.36 to 0.1 mS/m and from 2.4 to 0.13 mS/m for dry and wet skin, respectively. It was demonstrated that in the palm, the conductivity of the skin is higher and the permittivity much higher compared to the data given in the literature. This finding might be of interest because it increases the knowledge about skin dielectric properties importance when estimating the effects of low-frequency electromagnetic field exposure.
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Bioimpedance has been widely used in many health areas. The ability of the human body cells , as the response for the alternate electric current flow, can provide valuable information about health status of the subject. This work presents... more
Bioimpedance has been widely used in many health areas. The ability of the human body cells , as the response for the alternate electric current flow, can provide valuable information about health status of the subject. This work presents a low-cost body impedance measuring system. The system is composed by the impedance meter AD5933, a four-electrode front-end circuit, a microcontroller sys tem and a computer system for processing, visualization and data sto- rage. The developed system calculates the resistance, reactance and phase angle (PA) from measured impedance spectra. Two subjects were assessed and the bioimpedance data was com- pared with data encountered in the literature. Predictive equations were used to calculate fat-free mass (FFM), fat mass percentage (%FM) and total body water (TBW). Preliminary results describe consistent with the reference values in the literature, indicating that the developed device is proper to body impedance measurement. The body impedance analyzer developed in this work was conducted according to the requirements of healthcare applications, such as portability and low cost. It can be concluded that the developed system can be used for body composition assessment over a wide aging range.
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Pressure sensing by measuring the impedance of soft matter, like hydrogels and rubber, has so far posed the problems of low conductivity and hysteresis. Further modifications in the materials to enhance their properties are needed. A... more
Pressure sensing by measuring the impedance of soft matter, like hydrogels and rubber, has so far posed the problems of low conductivity and hysteresis. Further modifications in the materials to enhance their properties are needed. A pressure sensor using a simple gelatin/agarose double network gel placed between two Ag/AgCl electrodes is presented. The impedance spectra from 100 Hz to 1 MHz were investigated and admittance calculated. Both response time and hysteresis were also investigated. All the experiments were made using an impedance analyzer from Zurich Instruments. Results showed that the lowest standard deviation is at 3.5 kHz. It was found that the admittance increases exponentially from 7.9 to approximately 11.7 mS with increasing the mechanical load at 3.5 kHz. The highest hysteresis of about ±7.6% was found to be at zero load. The measured response time of the gel impedance was approximately 0.5 s, which makes the double network gel feasible for real time pressure monitoring. Mechanical tests measuring the force on the gel due to deformation showed little influence of the gel structure on the impedance. Thus it was concluded that the change of the distance in between the electrodes is responsible for the impedance change of the gel. Calibrations will be necessary for practical applications, since the gel impedance changes as environmental conditions change. This sensor showed better results as compared to conductive rubber published in the literature. It can be concluded that agarose/gelatin gels provide a cheap and easy to fabricate pressure measuring device.
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Visual techniques for qualitative assessment of roads, which rank the roads either good or not, have been widely used by the International Confederation of Transport. Although there are quantitative techniques, such as IRI (International... more
Visual techniques for qualitative assessment of roads, which rank the roads either good or not, have been widely used by the International Confederation of Transport. Although there are quantitative techniques, such as IRI (International Index Roughness), the use of these techniques involves a higher cost technique compared to the visual one due to the fact that there is a need of special and quite expensive equipment. In this work we developed a new quantitative indicator of roads able to evaluate and compare them in terms of its surface quality without relying on visual analysis. A low-cost acquisition system based on an analog 3-axis accelerometer and a microcontroller was developed. Also, it was developed an algorithm able to evaluate and rank the road on a scale ranging from 0 to 5. Two roads visually rated as good and bad were used as references. It was tested 3 different types of roads, with or without holes. Both tests were conducted with a vehicle running at 40, 50 and 60 km/h. The results showed that the greater the amount of holes or unevenness the worst the quality indicator and that this depends on the speed of the vehicle. It was concluded that a quantitative analysis of road might be automatically done by using a low cost measuring system.
Electrical Impedance Tomography design can be simplified to obtain a low cost 16 electrodes edema monitoring clinical instrument by using voltage measurement multiplexing. Multiplexers introduce errors, which we have estimated by... more
Electrical Impedance Tomography design can be simplified to obtain a low cost 16 electrodes edema monitoring clinical instrument by using voltage measurement multiplexing. Multiplexers introduce errors, which we have estimated by consecutive phantom measurements both using voltage multiplexers and by selecting the electrodes by hand, all other things being the same. Noise is taken care of by averaging. The EIDORS reconstruction of the phantom with multiplexed measurements is compared to the hand-selected electrode measurements reconstruction. The difference image obtained is considered an estimation of the multiplexer induced error. This measurement error is subtracted from the multiplexed object measurement matrix, giving a modified reconstruction which is closer to the hand-selected electrodes measurement based reconstruction than the multiplexed reconstruction. The quality factor of the uncorrected multiplexer obtained image of 57% is increased to 83% which is the best increase o...
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Current sources play an essential role in tissue excitation used in bioelectrical impedance spectroscopy. Most investigations use Howland current sources that, despite their practicality and simplified implementation, have operating... more
Current sources play an essential role in tissue excitation used in bioelectrical impedance spectroscopy. Most investigations use Howland current sources that, despite their practicality and simplified implementation, have operating frequency limitations and dependence on the load impedance due to theirs narrow output impedance, specially at higher frequencies. The objective of this work is to propose model for a robust current-controlled sinusoidal oscillator. The oscillator is based on fully analog electronics, which enables controlling oscillation phase and amplitude by using a voltage reference. The mathematical model is based on Pyragas control application to the classical harmonic oscillator. From the modelling process, it was build an oscillator topology based on second-generation current carriers and on transconductance amplifiers. The reference signal (Fsync) was a sinusoidal voltage source having a frequency of 1MHz and an amplitude of 1Vpp. The oscillator output current s...
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This work aimed to develop an innovative composite material consisting of graphene oxide films coated with silver nanowires (AgNWs)/poly(3-hexylthiophene) (P3HT). Translucent chemically reduced graphene oxide (CGO) films, presenting... more
This work aimed to develop an innovative composite material consisting of graphene oxide films coated with silver nanowires (AgNWs)/poly(3-hexylthiophene) (P3HT). Translucent chemically reduced graphene oxide (CGO) films, presenting electrical conductivity of ca. 5.2 × 101 S/m, as well as graphene oxide (GO) films, have been coated with high aspect ratio AgNWs (78 ± 20 nm diameter and ca. 10-µm length) and undoped P3HT, by casting and dip-coating. The presence of AgNWs favored the formation of H-aggregates of P3HT, both in toluene solution and in the films, lowering the degree of ordering of P3HT chains. The nanowires also tend to agglomerate in the presence of the conjugated polymer during the preparation of casted and dip-coating films from toluene solutions. Thus, AgNWs/P3HT films presented capacitive impedances similar to that of dielectric materials, while AgNWs/P3HT/CGO films showed behavior of resistive materials with conductivities between 1.5 and 4.2 × 101 S/m. Impedance and UV–Vis results also suggest that casted films present a better organization of P3HT chains than those deposited by dip-coating.
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Hemiparesis resulting from a stroke has a direct impact on patients’ daily activities. New approaches for motor rehabilitation include Serious Games (SG) because they include (in a motivating way) the three fundamental elements for... more
Hemiparesis resulting from a stroke has a direct impact on patients’ daily activities. New approaches for motor rehabilitation include Serious Games (SG) because they include (in a motivating way) the three fundamental elements for rehabilitation: intensive, repetitive and task-oriented training. This study aims to evaluate the therapeutic effects of a biomedical SG and a scoring system developed for lower limb motor rehabilitation of hemiparetic stroke patients. The SG was inspired by the classic videogame called Pong, where the goal is to control a tennis racquet, but using muscular strength. A knee extensor apparatus was adapted with a load cell and mechanical adjustments for measuring the muscular strength of the quadriceps femoris (QFG) and hamstrings (HSG). A scoring system was proposed to evaluate muscular control. Eleven hemiparetic stroke patients participated in an exercise program using the SG twice a week for ten weeks and only the paretic side was trained. Significant Effect Sizes (<inline-formula> <tex-math notation="LaTeX">${d}$ </tex-math></inline-formula>) were found for QFG strength (<inline-formula> <tex-math notation="LaTeX">${d}={0.5};{p}={0.021}$ </tex-math></inline-formula>), QFG control (<inline-formula> <tex-math notation="LaTeX">${d}={1.1}; {p} < {0.001}$ </tex-math></inline-formula>), HSG strength (<inline-formula> <tex-math notation="LaTeX">${d}={1.1}; {p} ={0.001}$ </tex-math></inline-formula>), HSG control (<inline-formula> <tex-math notation="LaTeX">${d}={1.5}; {p} ={0.003}$ </tex-math></inline-formula>), functional mobility (<inline-formula> <tex-math notation="LaTeX">${d}={0.3}; {p} < {0.001}$ </tex-math></inline-formula>), gait speed (<inline-formula> <tex-math notation="LaTeX">${d}={0.4}; {p}={0.007}$ </tex-math></inline-formula>) and motor recovery (<inline-formula> <tex-math notation="LaTeX">${d}={1.0}; {p} < {0.001}$ </tex-math></inline-formula>). Results indicate that the intervention of a SG with both proper apparatus and evaluation system may effectively promote lower limb motor rehabilitation of hemiparetic stroke patients.
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Electrical impedance spectroscopy combined with Neural Networks can be a powerful combination to identify biological materials. This paper utilizes a data set containing two biological samples taken from different species and applies the... more
Electrical impedance spectroscopy combined with Neural Networks can be a powerful combination to identify biological materials. This paper utilizes a data set containing two biological samples taken from different species and applies the most popular methods of dimensionality reduction. This is done in order to find out which method is able to minimize computational demand and maximize accuracy in the classification test. This paper proposes that the classic PCA method is the fastest and the most accurate under the configurations used.
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Multifrequency Electrical Impedance Tomography is a technique for estimating the impedance distribution of a region of interest, for example a part of the human body. It is an imaging technique that distinguishes biological tissues by... more
Multifrequency Electrical Impedance Tomography is a technique for estimating the impedance distribution of a region of interest, for example a part of the human body. It is an imaging technique that distinguishes biological tissues by their unique spectrum of conductivity. Its main advantages are the low cost, absence of ionizing radiation to patients undergoing the equipment and it is a portable equipment and can be easily transported according to the patient's needs.<br> n this work a systematic review was conducted to investigate innovative solutions for the development of a portable Multifrequency Electrical Impedance Tomograph. In order to improve deficiencies related to image quality.<br> It was verified in the analyzed works great use of the modified Howland current source, multiplexing based on Field Programmable Gate Array, MATLAB and EIDORS software. This review shows that there is a large trend in the use of open technologies such as Arduino and Raspberry ...
... on Fiber Optics Optoelectronics and Photonics (Cochin, India) paper Bio 2.2.1 [5] Silva JCC, Ramos AM, Carvalho L, Nogueira RN, Ballu A ... 20 38896 [14] Watts DC, Marouf AS and Al-Hindi AM 2001 Photo-polymerization shrinkage-stress... more
... on Fiber Optics Optoelectronics and Photonics (Cochin, India) paper Bio 2.2.1 [5] Silva JCC, Ramos AM, Carvalho L, Nogueira RN, Ballu A ... 20 38896 [14] Watts DC, Marouf AS and Al-Hindi AM 2001 Photo-polymerization shrinkage-stress kinetics in resin-composites: methods ...
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The increase in the world population makes the search for innovative health technologies constant. Bioelectrical impedance is in the spotlight because of its wide range of uses and its inexpensiveness compared to other non-invasive... more
The increase in the world population makes the search for innovative health technologies constant. Bioelectrical impedance is in the spotlight because of its wide range of uses and its inexpensiveness compared to other non-invasive technologies. Bioelectrical impedance can monitor the body composition by estimating the nutrition status, obesity levels, and the hydration status. Beyond this, it can help in mechanic ventilation and measure glucose in a non-invasive way. So why has this technology been less used in clinical practice? One of the answers is about how little information physicians have with the literature on bioelectrical impedance devices. It is a multifactorial problem that ranges from the database used to the way in which articles are written. This narrative review looks to bring bioelectric impedance knowledge closer to health care workers. Therefore, we simplify technical information and prioritize the use indications, making it friendlier to health care professionals.
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This volume presents the proceedings of CLABIO 2015 - II Latin American Conference on Bioimpedance, held in Montevideo, Uruguay - September 30 - October 02, 2015. The works cover a broad range in Biomedical Engineering and Computing,... more
This volume presents the proceedings of CLABIO 2015 - II Latin American Conference on Bioimpedance, held in Montevideo, Uruguay - September 30 - October 02, 2015. The works cover a broad range in Biomedical Engineering and Computing, Medical Physics and Medical Sciences, Environment, Biology and Chemistry. The topics are: ·Bioimpedance Applications ·Bioimpedance Instrumentation ·Body and Tissue Composition ·Cell Culture and Cell Suspension ·Electrical Impedance Tomography ·Electrode Modelling ·Magnetic Induction - Electrical Impedance Tomography ·Magnetic Resonance - Electrical Impedance Tomography ·Nonlinear Phenomena ·Organ and Tissue Impedance ·Plant Tissue Impedance ·Skin Impedance Modelling ·Technological Advances in Bioimpedance ·Theory and Modelling.