Sensor, Signal, and Imaging Informatics in 2017.

Objective To summarize significant contributions to sensor, signal, and imaging informatics literature published in 2017.Methods PubMed® and Web of Science® were searched to identify the scientific publications published in 2017 that addressed sensors, signals, and imaging in medical informatics. Fifteen papers were selected by consensus as candidate best papers. Each candidate article was reviewed by section editors and at least two other external reviewers. The final selection of the four best papers was conducted by the editorial board of the International Medical Informatics Association (IMIA) Yearbook.Results The selected papers of 2017 demonstrate the important scientific advances in management and analysis of sensor, signal, and imaging information.ConclusionThe growth of signal and imaging data and the increasing power of machine learning techniques have engendered new opportunities for research in medical informatics. This synopsis highlights cutting-edge contributions to the science of Sensor, Signal, and Imaging Informatics

Multimodal Wearable Sensors for Human-Machine Interfaces

Certain areas of the body, such as the hands, eyes and organs of speech production, provide high-bandwidth information channels from the conscious mind to the outside world. The objective of this research was to develop an innovative wearable sensor device that records signals from these areas more conveniently than has previously been possible, so that they can be harnessed for communication. A novel bioelectrical and biomechanical sensing device, the wearable endogenous biosignal sensor (WEBS), was developed and tested in various communication and clinical measurement applications. One ground-breaking feature of the WEBS system is that it digitises biopotentials almost at the point of measurement. Its electrode connects directly to a high-resolution analog-to-digital converter. A second major advance is that, unlike previous active biopotential electrodes, the WEBS electrode connects to a shared data bus, allowing a large or small number of them to work together with relatively few physical interconnections. Another unique feature is its ability to switch dynamically between recording and signal source modes. An accelerometer within the device captures real-time information about its physical movement, not only facilitating the measurement of biomechanical signals of interest, but also allowing motion artefacts in the bioelectrical signal to be detected. Each of these innovative features has potentially far-reaching implications in biopotential measurement, both in clinical recording and in other applications. Weighing under 0.45 g and being remarkably low-cost, the WEBS is ideally suited for integration into disposable electrodes. Several such devices can be combined to form an inexpensive digital body sensor network, with shorter set-up time than conventional equipment, more flexible topology, and fewer physical interconnections. One phase of this study evaluated areas of the body as communication channels. The throat was selected for detailed study since it yields a range of voluntarily controllable signals, including laryngeal vibrations and gross movements associated with vocal tract articulation. A WEBS device recorded these signals and several novel methods of human-to-machine communication were demonstrated. To evaluate the performance of the WEBS system, recordings were validated against a high-end biopotential recording system for a number of biopotential signal types. To demonstrate an application for use by a clinician, the WEBS system was used to record 12‑lead electrocardiogram with augmented mechanical movement information

Ultra low power wearable sleep diagnostic systems

Sleep disorders are studied using sleep study systems called Polysomnography that records several biophysical parameters during sleep. However, these are bulky and are typically located in a medical facility where patient monitoring is costly and quite inefficient. Home-based portable systems solve these problems to an extent but they record only a minimal number of channels due to limited battery life. To surmount this, wearable sleep system are desired which need to be unobtrusive and have long battery life. In this thesis, a novel sleep system architecture is presented that enables the design of an ultra low power sleep diagnostic system. This architecture is capable of extending the recording time to 120 hours in a wearable system which is an order of magnitude improvement over commercial wearable systems that record for about 12 hours. This architecture has in effect reduced the average power consumption of 5-6 mW per channel to less than 500 uW per channel. This has been achieved by eliminating sampled data architecture, reducing the wireless transmission rate and by moving the sleep scoring to the sensors. Further, ultra low power instrumentation amplifiers have been designed to operate in weak inversion region to support this architecture. A 40 dB chopper-stabilised low power instrumentation amplifiers to process EEG were designed and tested to operate from 1.0 V consuming just 3.1 uW for peak mode operation with DC servo loop. A 50 dB non-EEG amplifier continuous-time bandpass amplifier with a consumption of 400 nW was also fabricated and tested. Both the amplifiers achieved a high CMRR and impedance that are critical for wearable systems. Combining these amplifiers with the novel architecture enables the design of an ultra low power sleep recording system. This reduces the size of the battery required and hence enables a truly wearable system.Open Acces

Index to NASA Tech Briefs, 1972

Abstracts of 1972 NASA Tech Briefs are presented. Four indexes are included: subject, personal author, originating center, and Tech Brief number

Calcium Remodeling through Different Signaling Pathways in Heart Failure: Arrhythmogenesis Studies of Pyk2, Dystrophin, and β-adrenergic Receptor Signaling

Heart failure is a common clinical syndrome that ensues when the heart is no longer able to generate sufficient cardiac output to meet the demands of the body. It is one of the leading causes of death worldwide but with limited and non-ideal therapies at the moment. One reason behind this may be the complexity of significant alterations in multiple signaling pathways and concomitant structural and functional remodeling, especially Ca handling. Ca is critical in both the electrical and mechanical properties of cardiac myoctyes, and much is known about ionic currents and the normal excitation-contraction coupling process. In heart failure, distinct impaired signaling pathways induce significant alterations in how cardiac Ca handling is regulated. These alterations either directly cause certain arrhythmias or facilitate arrhythmias by association with electrical remodeling. The goal of this dissertation was to investigate the mechanisms of calcium remodeling through different signaling pathways in heart failure, and mechanisms on how the intricate and dynamic interactions between Ca handling and signaling pathways impairment facilitate arrhythmias in heart failure. To achieve this goal, a dual optical mapping system was designed to investigate electrical activity and Ca transient simultaneously. High spatio-temporal resolution mapping allows for quantifying conduction, repolarization and Ca cycling, especially on the interactions between action potential and Ca handling. In this dissertation, I investigated Ca remodeling in three different signaling pathways: stress activated signaling, cytoskeletal signaling and β adrenergic receptor signaling pathway. Proline-rich tyrosine kinase 2: Pyk2) is a non-receptor protein kinase regulated by intracellular Ca. It mediates a typical stress activated signaling pathways along with c-Src, P38 MAPK and regulates a broad range of key biological responses. By optically mapping the genetically engineered mouse model: Pyk2 knockout, I detected a protective role of Pyk2 with respect to ventricular tachyarrhythmia during parasympathetic stimulation by regulation of gene expression related to calcium handling. The mdx mouse model was introduced in the investigation of cytoskeletal signaling pathway. mdx mice is a common model for Duchenne muscular dystrophy, which is a clinical syndrome resulted from recessive of dystrophin and eventually develops into heart failure. The project suggested the association of mechanical stimulation and deficiency of dystrophin account for the cardiac mechanical defects and resulting Ca mishandling, but not either of the two above-mentioned entities alone. Ca mishandling leads to Ca cycling dispersion, which facilitates generation of arrhythmias. β Adrenergic receptor signaling pathway was investigated on explanted donor and failing human hearts. Distinct β adrenergic receptor subtypes were found to regulate remodeling differently. The association between remodeling of action potential and Ca transient provides crucial arrhythmic drivers and substrate in heart failure