Evaluation of Data Processing and Artifact Removal Approaches Used for Physiological Signals Captured Using Wearable Sensing Devices during Construction Tasks

Wearable sensing devices (WSDs) have enormous promise for monitoring construction worker safety. They can track workers and send safety-related information in real time, allowing for more effective and preventative decision making. WSDs are particularly useful on construction sites since they can track workers’ health, safety, and activity levels, among other metrics that could help optimize their daily tasks. WSDs may also assist workers in recognizing health-related safety risks (such as physical fatigue) and taking appropriate action to mitigate them. The data produced by these WSDs, however, is highly noisy and contaminated with artifacts that could have been introduced by the surroundings, the experimental apparatus, or the subject’s physiological state. These artifacts are very strong and frequently found during field experiments. So, when there is a lot of artifacts, the signal quality drops. Recently, artifacts removal has been greatly enhanced by developments in signal processing, which has vastly enhanced the performance. Thus, the proposed review aimed to provide an in-depth analysis of the approaches currently used to analyze data and remove artifacts from physiological signals obtained via WSDs during construction-related tasks. First, this study provides an overview of the physiological signals that are likely to be recorded from construction workers to monitor their health and safety. Second, this review identifies the most prevalent artifacts that have the most detrimental effect on the utility of the signals. Third, a comprehensive review of existing artifact-removal approaches were presented. Fourth, each identified artifact detection and removal approach was analyzed for its strengths and weaknesses. Finally, in conclusion, this review provides a few suggestions for future research for improving the quality of captured physiological signals for monitoring the health and safety of construction workers using artifact removal approaches

Advanced sensors technology survey

This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed

Desarrollo de un sistema IoT integrado con dispositivos de eHealth para la detección automática de la variabilidad cardiaca

El presente trabajo final de grado tiene como objetivo principal el diseño e implementación de una solución portable para pacientes con problemas cardiovasculares relacionados con arritmias y trastornos en la frecuencia cardíaca. Dicha solución se constituirá a través de un sistema de sensorización, procesado de datos y comunicación que haga uso de las últimas tecnologías en el ámbito de la eHealth y el IoT, e implemente los estándares de interoperabilidad para garantizar un uso extendido a bajo coste.Palao Cruz, C. (2017). Desarrollo de un sistema IoT integrado con dispositivos de eHealth para la detección automática de la variabilidad cardiaca. http://hdl.handle.net/10251/91750TFG

Refined electrophysiological recording and processing of neural signals from the retina and ascending visual pathways

The purpose of this thesis was the development of refined methods for recording and processing of neural signals of the retina and ascending visual pathways. The first chapter describes briefly the fundamentals of the human visual system and the basics of the functional testing of the retina and the visual pathways. The second and third chapters are dedicated to the processing of visual electrophysiological data using the newly developed software ERG Explorer, and present a proposal for an open and standardized data format, ElVisML, for future proof storage of visual electrophysiological data. The fourth chapter describes the development and application of two novel electrodes: First a contact lens electrode for the recording of electrical potentials of the ciliary muscle during accommodation, and second, the marble electrode, which is made of a super-absorbant polymer and allows for a preparation-free recording of visual evoked potentials. Results obtained in studies using the both electrodes are presented. The fifths and last chapter of the thesis presents the results from four studies within the field of visual electrophysiology. The first study examines the ophthalmological assessment of cannabis-induced perception disorder using electrophysiological methods. The second study presents a refined method for the objective assessment of the visual acuity using visual evoked potentials and introduces therefore, a refined stimulus paradigm and a novel method for the analysis of the sweep VEP. The third study presents the results of a newly developed stimulus design for full-field electrophysiology, which allows to assess previously non-recordable electroretinograms. The last study describes a relation of the spatial frequency of a visual stimulus to the amplitudes of visual evoked potentials in comparison to the BOLD response obtained using functional near-infrared spectroscopy and functional magnetic resonance imaging

Modular Instrumentation for Controlling and Monitoring In-Vitro Cultivation Environment and Image-based Functionality Measurements of Human Stem Cells

Artificial animal cell culture was successfully developed by Ross Harrison in 1907. But it was not until the 1940’s and 1950’s that several developments occurred, which expedited the cell culturing in-vitro (C-Vitro) to be a consistent and reproducible technique to study isolated living-cells in a controlled environment. Currently, CVitro is one of the major tools in cellular and molecular biology both in the academia and industry. They are extensively utilised to study the cellular physiology/biochemistry, to screen drugs/therapeutic compounds, to understand the effects of drugs/toxic compounds and also to identify the pathways of carcinogenesis/mutagenesis. It is also used in large scale manufacturing of vaccines and therapeutic proteins. In any experimental setup, it is important that the C-Vitro model should represent the physiological phenomena of interest with reasonable accuracy so that all experimental results are statistically consistent and reproducible. In this direction, sensors and measurement systems play important roles in in-situ detection and/or control/manipulation of cells/tissues/environment. This thesis aimed to develop new technology for tailored cell culturing and integrated measurements. Firstly, design and assembly of a portable Invert-upright microscope interchangeable modular cell culturing platform (iuCMP) was envisioned. In contrast to conventional methods, micro-scaled systems mimic the cells' natural microenvironment more precisely, facilitating accurate and tractable models. The iuCMP integrates modular measurement schemes with a mini culture chamber using biocompatible cell-friendly materials, automated environment-control (temperature and gas concentrations), oxygen sensing and simultaneous functional measurements (electrophysiological and image-based). Time lapse microscopy is very useful in cell biology, but integration of advanced >i>in-vitro/device based biological systems (e.g. lab/organ/body-on-chips, or mini-bioreactors/microfluidic systems) into conventional microscopes can be challenging in several circumstances due to multiple reasons. But in iuCMP the main advantage is, the microscope can be switched either as an inverted or as an upright system and therefore can accommodate virtually any in-vitro device. It can capture images from regions that are otherwise inaccessible by conventional microscopes, for example, cells cultured on physical or biochemical sensor systems. The modular design also allows accommodating more sensor or measurement systems quite freely. We have demonstrated the system for video-based beating analysis of cardiomyocytes, cell orientation analysis on nanocellulose, and simultaneous long-term in-situ microscopy with oxygen and temperature sensing in hypoxia. In an example application, the system was utilised for long-term temperature stressing and simultaneous mechanobiological analysis of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). For this the iuCMP together with a temperature sensor plate (TSP) and a novel non-invasive beating analysis software (CMaN—cardiomyocyte function analysis tool, scripted as a subpart of this thesis), was applied for automated temperature response studies in hiPSC-CM cultures. In-situ temperature sensing is usually challenging with bulky external sensors, but TSPs solved this issue. In the temperature response study, we showed that the relationship between hiPSC-CM beating frequency and temperature is non-linear and measured the Q10 temperature coefficients. Moreover, we observed the hiPSC-CM contractile networking, including propagation of the action potential signal between dissociated clusters and their non-invasive measurements. It was the first case where these events were reported in hiPSC-CM clusters and their noninvasive measurements by image processing. The software CMaN comes with a user-friendly interface and, is equipped with features for batch processing, movement centre detection and cluster finding. It can extract six different signals of the contractile motion of cardiomyocytes (clusters or single cells) per processing. This ensures a minimum of one useful beating signal even in the cases of complex beating videos. On the processing end, compared to similar tools, CMaN is faster, more sensitive, and computationally less expensive and allows ROI based processing. In the case of healthy cells, the waveform of the signal from the CMaN resembles an ECG signal with positive and negative segments, allowing the computation of contraction and relaxation features separately. In addition to iuCMP, a Modular optical pH measurement system (MO-pH) for 24/7 non-contact cell culture measurements was also developed. The MO-pH incorporates modular sterilisable optical parts and is used in phenol-red medium cell cultures. The modular assembly of MO-pH cassettes is unique and reusable. Measurements are carried out in a closed flow system without wasting any culture medium and requires no special manual attention or recalibrations during culture. Furthermore, a new absorption correction model was put forward that minimised errors caused e.g. by biolayers in spectrometric pH measurement, which improved the pH measurement accuracy. MO-pH has been applied in long-term human adipose stem cells (hASC) expansion cultures in CO2 dependent and independent media. Additionally, the MO-pH was also utilised to comprehend the behaviour of pH, temperature and humidity in water jacked incubators as well as to record the pH response as a function of temperature in the presence and absence of CO2 in the context of stem cell cultures. The resulting plots clearly showed the interplay between measured parameters indicating a few stress sources present all through the culture. Additionally, it provided an overall picture of behaviour of critical control parameters in an incubator and pointed out the need for bioprocess systems with automatic process monitoring and smart control for maximum yield, optimal growth and maintenance of the cells. Besides, we also integrated MO-pH into flasks with reclosable lids (RL-F) and tested its applicability in stem cell cultures. A standalone system around an RL-F flask was built by combining the cell culture, medium perfusion and optical measurements. The developed RL-F system has been successfully tested in ASC-differentiation cultures. Finally, a few trial experiments for image-based pH estimation aimed for iuCMP have also been carried out. This includes tests with LCD illumination, optical projection tomography, and webcam systems. In reality, the pH is not distributed uniformly in tissues, and has shown a gradient of up to 1.0 pH unit within 1 cm distance. Therefore, producing reliable pH maps also in in-vitro can be important in understanding various common pathologies and location of lesions. A reliable and adequately developed long-term pH mapping method will be an important addition into the iuCMP

Low-voltage embedded biomedical processor design

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 180-190).Advances in mobile electronics are fueling new possibilities in a variety of applications, one of which is ambulatory medical monitoring with body-worn or implanted sensors. Digital processors on such sensors serve to analyze signals in real-time and extract key features for transmission or storage. To support diverse and evolving applications, the processor should be flexible, and to extend sensor operating lifetime, the processor should be energy-efficient. This thesis focuses on architectures and circuits for low power biomedical signal processing. A general-purpose processor is extended with custom hardware accelerators to reduce the cycle count and energy for common tasks, including FIR and median filtering as well as computing FFTs and mathematical functions. Improvements to classic architectures are proposed to reduce power and improve versatility: an FFT accelerator demonstrates a new control scheme to reduce datapath switching activity, and a modified CORDIC engine features increased input range and decreased quantization error over conventional designs. At the system level, the addition of accelerators increases leakage power and bus loading; strategies to mitigate these costs are analyzed in this thesis. A key strategy for improving energy efficiency is to aggressively scale the power supply voltage according to application performance demands. However, increased sensitivity to variation at low voltages must be mitigated in logic and SRAM design. For logic circuits, a design flow and a hold time verification methodology addressing local variation are proposed and demonstrated in a 65nm microcontroller functioning at 0.3V. For SRAMs, a model for the weak-cell read current is presented for near-V supply voltages, and a self-timed scheme for reducing internal bus glitches is employed with low leakage overhead. The above techniques are demonstrated in a 0.5-1.OV biomedical signal processing platform in 0.13p-Lm CMOS. The use of accelerators for key signal processing enabled greater than 10x energy reduction in two complete EEG and EKG analysis applications, as compared to implementations on a conventional processor.by Joyce Y. S. Kwong.Ph.D

From Ecological Epitome to Medical Model: An investigation into Applications for the use of Daphnia in Heart Science.

The primary aim of this research was to determine whether Daphnia might become a model for cardiovascular concentration-response trials. This would provide a high throughput means of testing cardiac therapeutics without resort to small mammal trials. We found Daphnia are inappropriate in this context due to high population variance and sensitivity to small, subtle, environmental changes. A new aim was developed to determine whether beat-to-beat variation could be correlated with an individual’s response to toxic insult. Further, to develop more accurate and efficient means of gathering heart rhythm data by recording heart movement from whole live Daphnia. This opens the way to individualising cardio therapeutics; by correlating the stability of individual hearts with response to cardiac insult, regression analysis provides a means of finding a prediction tool. Daphnia are a convenient example here, but successful scoring systems might also be applied to the human heart via analysis of ECG readouts. Collecting signals from whole live Daphnia did not fulfil the goal of gathering heart data as this instead recorded limb movement. However, this provides a means of improving toxicology testing in aquatic ecology. This thesis offers three contributions to knowledge: 1. Daphnia are an inappropriate model for cardiovascular therapeutic dose-response trials due to extreme environmental sensitivities. 2. Baseline heart rhythm can be correlated with paired response to cardiac insult, with significance at the 0.01 alpha level, using an adjusted version of the Lyapnov equation; Finite Time Growth (Wessel, 2010). However, this is only if population variation is adequate. It is better applied to a natural in situ population than a homegenic lab population. 3. A novel technique for measuring Daphnia electromechanical movement records feeding limbs rather than the heart. This offers a novel and more efficient technique for aquatic ecotoxicology, where visual observation or films of the same are currently used