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Farooq, Muhammad, Talha Iqbal, Patricia Vazquez, Nazar Farid, Sudhin Thampi, William Wijns i Atif Shahzad. "Thin-Film Flexible Wireless Pressure Sensor for Continuous Pressure Monitoring in Medical Applications". Sensors 20, nr 22 (20.11.2020): 6653. http://dx.doi.org/10.3390/s20226653.
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Physiological pressure measurement is one of the most common applications of sensors in healthcare. Particularly, continuous pressure monitoring provides key information for early diagnosis, patient-specific treatment, and preventive healthcare. This paper presents a thin-film flexible wireless pressure sensor for continuous pressure measurement in a wide range of medical applications but mainly focused on interface pressure monitoring during compression therapy to treat venous insufficiency. The sensor is based on a pressure-dependent capacitor (C) and printed inductive coil (L) that form an inductor-capacitor (LC) resonant circuit. A matched reader coil provides an excellent coupling at the fundamental resonance frequency of the sensor. Considering varying requirements of venous ulceration, two versions of the sensor, with different sizes, were finalized after design parameter optimization and fabricated using a cost-effective and simple etching method. A test setup consisting of a glass pressure chamber and a vacuum pump was developed to test and characterize the response of the sensors. Both sensors were tested for a narrow range (0–100 mmHg) and a wide range (0–300 mmHg) to cover most of the physiological pressure measurement applications. Both sensors showed good linearity with high sensitivity in the lower pressure range <100 mmHg, providing a wireless monitoring platform for compression therapy in venous ulceration.
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Zhang, Changzhen, Deqin Xiao, Qiumei Yang, Zhifen Wen i Lishan Lv. "Review: Application of Infrared Thermography in Livestock Monitoring". Transactions of the ASABE 63, nr 2 (2020): 389–99. http://dx.doi.org/10.13031/trans.13068.
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HighlightsAs a non-invasive temperature detection technology, IRT can provide dynamic information on skin temperature changes caused by physiological processes of livestock.IRT will become a more valuable detection tool for evaluating various signs and behavior changes of livestock.With the continuous development of information technology, it is necessary to use IRT to explore more expected and innovative information.Abstract. Infrared thermography (IRT) is a non-invasive temperature detection technology characterized by non-destructive, long-distance measurement and high sensitivity. IRT measures mid-wave to long-wave infrared radiation emanating from objects and converts this radiation into visual images or videos of the temperature distribution and temperature changes. Because temperature is an important environmental parameter that affects livestock physiology and metabolic heat production, measurement of animal temperature and energy exchange in field environments is a useful tool for understanding physiological changes in animals. Traditional measurement methods of animal temperature are extremely time-consuming and labor-intensive. As a non-contact method, IRT provides a new method for physiological data acquisition. However, IRT is also subject to a number of uncertainties, thus requiring optimal modeling using built-in software. Therefore, this study reviews applications of IRT in livestock production, including reproduction, growth, and diseases, and discusses some of the better-known approaches and the latest research findings for IRT in livestock production. Keywords: Diseases, Growth, Infrared thermography, Reproduction.
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Coote, Joanna M., Ryo Torii i Adrien E. Desjardins. "Dynamic Characterisation of Fibre-Optic Temperature Sensors for Physiological Monitoring". Sensors 21, nr 1 (31.12.2020): 221. http://dx.doi.org/10.3390/s21010221.
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Fast, miniature temperature sensors are required for various biomedical applications. Fibre-optics are particularly suited to minimally invasive procedures, and many types of fibre-optic temperature sensors have been demonstrated. In applications where rapidly varying temperatures are present, a fast and well-known response time is important; however, in many cases, the dynamic behaviour of the sensor is not well-known. In this article, we investigate the dynamic response of a polymer-based interferometric temperature sensor, using both an experimental technique employing optical heating with a pulsed laser, and a computational heat transfer model based on the finite element method. Our results show that the sensor has a time constant on the order of milliseconds and a −6 dB bandwidth of up to 178 Hz, indicating its suitability for applications such as flow measurement by thermal techniques, photothermal spectroscopy, and monitoring of thermal treatments.
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González-Sánchez, Carlos, Juan-Carlos Fraile, Javier Pérez-Turiel, Ellen Damm, Jochen G. Schneider, Daniel Schmitt i Frank R. Ihmig. "Monitoring System for Laboratory Mice Transportation: A Novel Concept for the Measurement of Physiological and Environmental Parameters". Electronics 8, nr 1 (1.01.2019): 34. http://dx.doi.org/10.3390/electronics8010034.
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Laboratory mice are used in biomedical research as “models” for studying human disease. These mice may be subject to significant levels of stress during transportation that can cause alterations that could negatively affect the results of the performed investigation. Here, we present the design and realization of a prototypical transportation container for laboratory mice, which may contribute to improved laboratory animal welfare. This prototype incorporates electric potential integrated circuit (EPIC) sensors, which have been shown to allow the recording of physiological parameters (heart rate and breathing rate) and other sensors for recording environmental parameters during mouse transportation. This allows for the estimation of the stress levels suffered by mice. First experimental results for capturing physiological and environmental parameters are shown and discussed.
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Jegan R. i Nimi W.S. "Sensor Based Smart Real Time Monitoring of Patients Conditions Using Wireless Protocol". International Journal of E-Health and Medical Communications 9, nr 3 (lipiec 2018): 79–99. http://dx.doi.org/10.4018/ijehmc.2018070105.
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This article describes how physiological signal monitoring plays an important role in identifying the health condition of heart. In recent years, online monitoring and processing of biomedical signals play a major role in accurate clinical diagnosis. Therefore, there is a requirement for the developing of online monitoring systems that will be helpful for physicians to avoid mistakes. This article focuses on the method for real time acquisition of an ECG and PPG signal and it's processing and monitoring for tele-health applications. This article also presents the real time peak detection of ECG and PPG for vital parameters measurement. The implementation and design of the proposed wireless monitoring system can be done using a graphical programming environment that utilizes less power and a minimized area with reasonable speed. The advantages of the proposed work are very simple, low cost, easy integration with programming environment and continuous monitoring of physiological signals.
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Zimmermann, Peter, Andreas Weltin, Gerald Urban i Jochen Kieninger. "Active Potentiometry for Dissolved Oxygen Monitoring with Platinum Electrodes". Sensors 18, nr 8 (24.07.2018): 2404. http://dx.doi.org/10.3390/s18082404.
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Potentiometric oxygen monitoring using platinum as the electrode material was enabled by the combination of conventional potentiometry with active prepolarization protocols, what we call active potentiometry. The obtained logarithmic transfer function is well-suited for the measurement of dissolved oxygen in biomedical applications, as the physiological oxygen concentration typically varies over several decades. We describe the application of active potentiometry in phosphate buffered salt solution at different pH and ion strength. Sensitivity was in the range of 60 mV/dec oxygen concentration; the transfer function deviated from logarithmic behavior for smaller oxygen concentration and higher ion strength of the electrolyte. Long-term stability was demonstrated for 60 h. Based on these measurement results and additional cyclic voltammetry investigations a model is discussed to explain the potential forming mechanism. The described method of active potentiometry is applicable to many different potentiometric sensors possibly enhancing sensitivity or selectivity for a specific parameter.
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Yuan, Xiangwen, i Jiabin Zhang. "Real-Time Monitoring of Intraocular Pressure in Glaucoma Patients Using Wearable Mobile Medicine Devices". Journal of Healthcare Engineering 2022 (28.03.2022): 1–10. http://dx.doi.org/10.1155/2022/2271937.
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Glaucoma is caused by excessive aqueous humor in the eye, resulting in a continuous or intermittent increase of intraocular pressure, which exceeds the tolerance of the eyeball and damages the optic nerve. Existing treatments for glaucoma do not work well or have significant side effects. Intraocular pressure signal is a very important physiological signal that needs real-time and accurate monitoring in glaucoma patients, especially in severe glaucoma patients. Therefore, long-term, real-time, and accurate monitoring of intraocular pressure is of great significance for the diagnosis and treatment of glaucoma patients. The use of wearable devices for real-time ocular diagnosis and treatment of glaucoma patients is an effective approach. However, the current commonly used intraocular pressure measurement and monitoring technology is difficult to meet the diagnosis and monitoring needs of glaucoma patients in terms of size, measurement accuracy, power consumption, and intelligence. Therefore, facing the needs of glaucoma disease treatment, this topic studies an implantable flexible intraocular pressure sensor for long-term continuous monitoring of intraocular pressure in glaucoma patients and mainly focuses on the working principle, structural design, process fabrication, measurement and control system, characterization, and performance test of the intraocular pressure sensor. It is of great significance for personalized and accurate treatment of glaucoma patients.
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Ricke, Darrell O., James Harper, Anna Shcherbina, Nelson Chiu i Tara Boettcher. "Integrated Biomedical System". F1000Research 7 (8.02.2018): 162. http://dx.doi.org/10.12688/f1000research.13601.1.
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Background: Capabilities for generating and storing large amounts of data relevant to individual health and performance are rapidly evolving and have the potential to accelerate progress toward quantitative and individualized understanding of many important issues in health and medicine. Recent advances in clinical and laboratory technologies provide increasingly complete and dynamic characterization of individual genomes, gene expression levels for genes, relative abundance of thousands of proteins, population levels for thousands of microbial species, quantitative imaging data, and more – all on the same individual. Personal and wearable electronic devices are increasingly enabling these same individuals to routinely and continuously capture vast amounts of quantitative data including activity, sleep, nutrition, environmental exposures, physiological signals, speech, and neurocognitive performance metrics at unprecedented temporal resolution and scales. While some of the companies offering these measurement technologies have begun to offer systems for integrating and displaying correlated individual data, these are either closed/proprietary platforms that provide limited access to sensor data or have limited scope that focus primarily on one data domain (e.g. steps/calories/activity, genetic data, etc.). Methods: The Integrated Biomedical System is developed as a Ruby on Rails application with a relational database. Results: Data from multiple wearable monitors for activity, sleep, and physiological measurements, phone GPS tracking, individual genomics, air quality monitoring, etc. have been integrated into the Integrated Biomedical System. Conclusions: The Integrated Biomedical System is being developed to demonstrate an adaptable open-source tool for reducing the burden associated with integrating heterogeneous genome, interactome, and exposome data from a constantly evolving landscape of biomedical data generating technologies. The Integrated Biomedical System provides a scalable and modular framework that can be extended to include support for numerous types of analyses and applications at scales ranging from personal users, communities and groups, to potentially large populations.
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Swain, Kunjabihari, Murthy Cherukuri, Sunil Kumar Mishra, Bhargav Appasani, Suprava Patnaik i Nicu Bizon. "LI-Care: A LabVIEW and IoT Based eHealth Monitoring System". Electronics 10, nr 24 (16.12.2021): 3137. http://dx.doi.org/10.3390/electronics10243137.
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This paper presents a Laboratory Virtual Instrument Engineering Workbench (LabVIEW) and Internet of Things (IoT)-based eHealth monitoring system called LI-Care to facilitate the diagnosis of the health condition cost-effectively. The system measures the heart rate, body temperature, blood pressure, oxygen level, and breathing rate, and provides an electrocardiogram (ECG). The required sensors are integrated on a web-based application that keeps track of the essential parameters and gives an alarm indication if one or more physiological parameters go beyond the safe level. It also employs a webcam to obtain the patient view at any time. LabVIEW enables the effortless interfacing of various biomedical sensors with the computer and provides high-speed data acquisition and interactive visualizations. It also provides a web publishing tool to access the interactive window remotely through a web browser. The web-based application is accessible to doctors who are experts in that particular field. They can obtain the real-time reading and directly perform a diagnosis. The parameters measured by the proposed system were validated using the traditional measurement systems, and the Root Mean Square (RMS) errors were obtained for the various parameters. The maximum RMS error as a percentage was 0.159%, which was found in the temperature measurement, and its power consumption is 1 Watt/h. The other RMS errors were 0.05% in measurement of systolic pressure, 0.029% in measurement of diastolic pressure, 0.059% in measurement of breathing rate, 0.002% in measurement of heart rate, 0.076% in measurement of oxygen level, and 0.015% in measurement of ECG. The low RMS errors and ease of deployment make it an attractive alternative for traditional monitoring systems. The proposed system has potential applications in hospitals, nursing homes, remote monitoring of the elderly, non-contact monitoring, etc.
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Huang, Haoying, Ruijuan Qiu, Hongchao Yang, Feng Ren, Feng Wu, Yejun Zhang, Hong Zhang i Chunyan Li. "Advanced NIR ratiometric probes for intravital biomedical imaging". Biomedical Materials 17, nr 1 (24.12.2021): 014107. http://dx.doi.org/10.1088/1748-605x/ac4147.
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Abstract Near-infrared (NIR) fluorescence imaging technology (NIR-I region, 650–950 nm and NIR-II region, 1000–1700 nm), with deeper tissue penetration and less disturbance from auto-fluorescence than that in visible region (400–650 nm), is playing a more and more extensive role in the field of biomedical imaging. With the development of precise medicine, intelligent NIR fluorescent probes have been meticulously designed to provide more sensitive, specific and accurate feedback on detection. Especially, recently developed ratiometric fluorescent probes have been devoted to quantify physiological and pathological parameters with a combination of responsive fluorescence changes and self-calibration. Herein, we systemically introduced the construction strategies of NIR ratiometric fluorescent probes and their applications in biological imaging in vivo, such as molecular detection, pH and temperature measurement, drug delivery monitoring and treatment evaluation. We further summarized possible optimization on the design of ratiometric probes for quantitative analysis with NIR fluorescence, and prospected the broader optical applications of ratiometric probes in life science and clinical translation.
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Al-Naggar, Noman Q., Husam Mohammed Al-Hammadi, Adel Mohammed Al-Fusail i Zakarya Ali AL-Shaebi. "Design of a Remote Real-Time Monitoring System for Multiple Physiological Parameters Based on Smartphone". Journal of Healthcare Engineering 2019 (19.11.2019): 1–13. http://dx.doi.org/10.1155/2019/5674673.
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Background. Utilization of the widely used wearable sensor and smartphone technology for remote monitoring represents a healthcare breakthrough. This study aims to design a remote real-time monitoring system for multiple physiological parameters (electrocardiogram, heart rate, respiratory rate, blood oxygen saturation, and temperature) based on smartphones, considering high performance, autoalarm generation, warning transmission, and security through more than one method. Methods. Data on monitoring parameters were acquired by the integrated circuits of wearable sensors and collected by an Arduino Mega 250 R3. The collected data were transmitted via a Wi-Fi interface to a smartphone. A patient application was developed to analyze, process, and display the data in numerical and graphical forms. The abnormality threshold values of parameters were identified and analyzed to generate an autoalarm in the system and transmitted with data to a doctor application via a third-generation (3G) mobile network and Wi-Fi. The performance of the proposed system was verified and evaluated. The proposed system was designed to meet main (sensing, processing, displaying, real-time transmission, autoalarm generation, and threshold value identification) and auxiliary requirements (compatibility, comfort, low power consumption and cost, small size, and suitability for ambulatory applications). Results. System performance is reliable, with a sufficient average accuracy measurement (99.26%). The system demonstrates an average time delay of 14 s in transmitting data to a doctor application via Wi-Fi compared with an average time of 68 s via a 3G mobile network. The proposed system achieves low power consumption against time (4 h 21 m 30 s) and the main and auxiliary requirements for remotely monitoring multiple parameters simultaneously with secure data. Conclusions. The proposed system can offer economic benefits for remotely monitoring patients living alone or in rural areas, thereby improving medical services, if manufactured in large quantities.
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Cheng, Long. "Implementation of Snow and Ice Sports Health and Sports Information Collection System Based on Internet of Things". Journal of Healthcare Engineering 2022 (7.01.2022): 1–12. http://dx.doi.org/10.1155/2022/7411955.
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The promotion of ice and snow sports not only provides professional athletes for the Winter Olympics but also acts as appreciative mass bases for ice and snow sports. The appearance of ice and snow sports will bring a new consumption pattern and develop a new ice and snow industry. In this paper, an Internet of Things (IoT)-based sports information collection system which is specifically designed and developed for the healthcare domain specifically in the snow and ice sports is proposed. The physiological parameters such as body temperature, ECG, blood pressure, blood sugar, and blood oxygen saturation are captured through various monitoring devices. These physiological parameters are transmitted to the mobile device by the wireless module and mobile device that receives and displays these physiological parameters. A complete hardware design of the whole ice and snow sports health and sports information acquisition system, which is based on the Internet of Things, is given, and then, there is the overall design scheme of the system, such as adopted modular design for the system, attitude measurement unit, UWB positioning unit, data storage, and communication unit, respectively. The measurement results of the professional medical equipment are compared with those of acquisition equipment in real environment of ice and sports. These results have verified accuracy of data collected by acquisition equipment and meet the design requirements of the proposed system.
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Guk, Kyeonghye, Gaon Han, Jaewoo Lim, Keunwon Jeong, Taejoon Kang, Eun-Kyung Lim i Juyeon Jung. "Evolution of Wearable Devices with Real-Time Disease Monitoring for Personalized Healthcare". Nanomaterials 9, nr 6 (29.05.2019): 813. http://dx.doi.org/10.3390/nano9060813.
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Wearable devices are becoming widespread in a wide range of applications, from healthcare to biomedical monitoring systems, which enable continuous measurement of critical biomarkers for medical diagnostics, physiological health monitoring and evaluation. Especially as the elderly population grows globally, various chronic and acute diseases become increasingly important, and the medical industry is changing dramatically due to the need for point-of-care (POC) diagnosis and real-time monitoring of long-term health conditions. Wearable devices have evolved gradually in the form of accessories, integrated clothing, body attachments and body inserts. Over the past few decades, the tremendous development of electronics, biocompatible materials and nanomaterials has resulted in the development of implantable devices that enable the diagnosis and prognosis through small sensors and biomedical devices, and greatly improve the quality and efficacy of medical services. This article summarizes the wearable devices that have been developed to date, and provides a review of their clinical applications. We will also discuss the technical barriers and challenges in the development of wearable devices, and discuss future prospects on wearable biosensors for prevention, personalized medicine and real-time health monitoring.
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Lee, Ren-Guey, Chun-Chang Chen, Chun-Chieh Hsiao, Hsi-Wen Wang i Ming-Shen Wei. "SLEEP APNEA SYNDROME RECOGNITION USING THE GREYART NETWORK". Biomedical Engineering: Applications, Basis and Communications 23, nr 03 (czerwiec 2011): 163–72. http://dx.doi.org/10.4015/s1016237211002505.
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This study employs relational analysis and the GreyART network to identify and study the characteristics of electroencephalogram signals of sleep apnea syndrome (SAS). Seventeen raw electroencephalogram data records from the sleep database compiled by Massachusetts Institute of Technology (MIT) and Beth Israel Hospital (BIH) were used in conjunction with four wavelet decomposition steps to obtain the cD4 wavelet coefficient as input for the GreyART network. The GreyART network was then used for simulation training and testing in order to achieve the best recognition results. This study achieved an average recognition rate of 93.33% for electroencephalogram data record slp01b, and recognition rates during the training and testing stage for this record were 95.80% and 92.12%, respectively. This was the best recognition result for any of the 17 records. The overall average recognition rate for all 17 records was 78.10%. In comparison with past literature, this study's use of the GreyART network to recognize electroencephalogram signal characteristics of SAS possesses excellent reference value. To further reduce the costs and the physiological signal measurement items to make it easier for patients to use, this research also proposes to use a single type of physiological signals, electroencephalographic (EEG) signals, as the sole input as identification information to identify SAS diseases. EEG signal detection is utilized because it is nonintrusive, suitable for long-term monitoring and most importantly, it can be used to detect various types of abnormal physiological conditions in SAS, moods, sleep stages, heart rate abnormalities and mental states. In addition, constant monitoring of users in their familiar home environment can also be utilized as self-screening at home to reduce the burden of sleep medicine centers.
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Giuliano, Karen K. "Improving Patient Safety through the Use of Nursing Surveillance". Biomedical Instrumentation & Technology 51, s2 (1.01.2017): 34–43. http://dx.doi.org/10.2345/0899-8205-51.s2.34.
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Surveillance and monitoring each represent a distinct process in patient care. Monitoring involves observation, measurement, and recording of physiological parameters, while surveillance is a systematic, goal-directed process based on early detection of signs of change, interpretation of the clinical implications of such changes, and initiation of rapid, appropriate interventions. Through use of an illustrative clinical example based on Early Warning System scoring and rapid response teams, this article seeks to distinguish between nurse monitoring and surveillance to demonstrate the impact of surveillance on improving both care processes and patient care. Using a clinical example, differences between surveillance and monitoring as a trigger for deployment of the rapid response team were reviewed. The use of surveillance versus monitoring resulted in a mean reduction in rapid response team deployment time of 291 minutes. The median hospital length of stay for patients whose clinical care included using surveillance to initiate the deployment of the rapid response team was reduced by 4 days. Monitoring relies on observation and assessment while nursing surveillance incorporates monitoring with recognition and interpretation of the clinical implications of changes to guide decisions about subsequent actions. The clinical example described here supports that the use of an automated surveillance system versus monitoring had a measurable impact on clinical care.
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Ren, Limin, Kun Yu i Yisong Tan. "Applications and Advances of Magnetoelastic Sensors in Biomedical Engineering: A Review". Materials 12, nr 7 (7.04.2019): 1135. http://dx.doi.org/10.3390/ma12071135.
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We present a comprehensive investigation into magnetoelastic sensors (MES) technology applied to biomedical engineering. This includes the working principles, detection methods, and application fields of MES technology. MES are made of amorphous metallic glass ribbons and are wireless and passive, meaning that it is convenient to monitor or measure the parameters related to biomedical engineering. MES are based on the inverse magnetoelastic (Villari) effect. When MES are subjected to mechanical stress, their magnetic susceptibility will change accordingly. And the susceptibility of MES is directly related to their magnetic permeability. The varying permeability can positively reflect the applied stress. The various detection methods that have been developed for different field applications include measurement of force, stress, and strain, monitoring of various chemical indexes, and consideration of different biomedical parameters such as the degradation rate and force conditions of artificial bone, as well as various physiological indexes including ammonia level, glucose concentration, bacteria growth, and blood coagulation.
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Williams, H. J., J. Ryan Shipley, C. Rutz, M. Wikelski, M. Wilkes i L. A. Hawkes. "Future trends in measuring physiology in free-living animals". Philosophical Transactions of the Royal Society B: Biological Sciences 376, nr 1831 (28.06.2021): 20200230. http://dx.doi.org/10.1098/rstb.2020.0230.
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Thus far, ecophysiology research has predominantly been conducted within controlled laboratory-based environments, owing to a mismatch between the recording technologies available for physiological monitoring in wild animals and the suite of behaviours and environments they need to withstand, without unduly affecting subjects. While it is possible to record some physiological variables for free-living animals using animal-attached logging devices, including inertial-measurement, heart-rate and temperature loggers, the field is still in its infancy. In this opinion piece, we review the most important future research directions for advancing the field of ‘physiologging’ in wild animals, including the technological development that we anticipate will be required, and the fiscal and ethical challenges that must be overcome. Non-invasive, multi-sensor miniature devices are ubiquitous in the world of human health and fitness monitoring, creating invaluable opportunities for animal and human physiologging to drive synergistic advances. We argue that by capitalizing on the research efforts and advancements made in the development of human wearables, it will be possible to design the non-invasive loggers needed by ecophysiologists to collect accurate physiological data from free-ranging animals ethically and with an absolute minimum of impact. In turn, findings have the capacity to foster transformative advances in human health monitoring. Thus, we invite biomedical engineers and researchers to collaborate with the animal-tagging community to drive forward the advancements necessary to realize the full potential of both fields. This article is part of the theme issue ‘Measuring physiology in free-living animals (Part II)’.
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Vignali, Emanuele, Zaira Manigrasso, Emanuele Gasparotti, Benedetta Biffi, Luigi Landini, Vincenzo Positano, Claudio Capelli i Simona Celi. "Design, simulation, and fabrication of a three-dimensional printed pump mimicking the left ventricle motion". International Journal of Artificial Organs 42, nr 10 (3.07.2019): 539–47. http://dx.doi.org/10.1177/0391398819856892.
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The development of accurate replicas of the circulatory and cardiac system is fundamental for a deeper understanding of cardiovascular diseases and the testing of new devices. Although numerous works concerning mock circulatory loops are present in the current state of the art, still some limitations are present. In particular, a pumping system able to reproduce the left ventricle motion and completely compatible with the magnetic resonance environment to permit the four-dimensional flow monitoring is still missing. The aim of this work was to evaluate the feasibility of an actuator suitable for cardiovascular mock circuits. Particular attention was given to the ability to mimic the left ventricle dynamics including both compression and twisting with the magnetic resonance compatibility. In our study, a left ventricle model to be actuated through vacuum was designed. The realization of the system was evaluated with finite element analysis of different design solutions. After the in silico evaluation phase, the most suitable design in terms of physiological values reproduction was fabricated through three-dimensional printing for in vitro validation. A pneumatic experimental setup was developed to evaluate the pump performances in terms of actuation, in particular ventricle radial and longitudinal displacement, twist rotation, and ejection fraction. The study demonstrated the feasibility of a custom pneumatic pump for mock circulatory loops able to reproduce the physiological ventricle movement and completely suitable for the magnetic resonance environment.
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Protsak, E. S., Yu Yu Borshchev i M. M. Galagoudza. "The role of the main hemodynamic parameters assessing in modern experimental practice". Regional blood circulation and microcirculation 22, nr 1 (5.04.2023): 103–9. http://dx.doi.org/10.24884/1682-6655-2023-22-1-103-109.
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We report an analysis of published data concerning the measurement of systemic hemodynamic parameters in experiments on laboratory animals. The article highlights the influence of such issues as housing and husbandry, handling, the frequency of person contact, animal surgical modification and pharmacological support in the perioperative period on blood pressure and heart rate, the most frequently recorded parameters both in experiment and clinic. Published data should be taken into account when planning and preparing an experiment using biomedical animal models, as well as when developing and submitting a protocol to the bioethical commission. Assessment of systemic hemodynamics is an integral part of physiological monitoring in any surgery of animals allowing better standardization of experimental endpoints and timely correction of possible deviations.
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Feng, Huanhuan, Yaming Liu, Liang Feng, Limeng Zhan, Shuaishuai Meng, Hongjun Ji, Jiaheng Zhang i in. "Additively Manufactured Flexible Electronics with Ultrabroad Range and High Sensitivity for Multiple Physiological Signals’ Detection". Research 2022 (8.08.2022): 1–11. http://dx.doi.org/10.34133/2022/9871489.
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Flexible electronics can be seamlessly attached to human skin and used for various purposes, such as pulse monitoring, pressure measurement, tensile sensing, and motion detection. Despite their broad applications, most flexible electronics do not possess both high sensitivity and wide detection range simultaneously; their sensitivity drops rapidly when they are subjected to even just medium pressure. In this study, ultrabroad-range, high-sensitivity flexible electronics are fabricated through additive manufacturing to address this issue. The key to possess high sensitivity and a wide detection range simultaneously is to fabricate flexible electronics with large depth-width ratio circuit channels using the additive manufacturing inner-rinsing template method. These electronics exhibit an unprecedented high sensitivity of 320 kPa−1 over the whole detection range, which ranges from 0.3 to 30,000 Pa (five orders of magnitude). Their minimum detectable weight is 0.02 g (the weight of a fly), which is comparable with human skin. They can stretch to over 500% strain without breaking and show no tensile fatigue after 1000 repetitions of stretching to 100% strain. A highly sensitive and flexible electronic epidermal pulse monitor is fabricated to detect multiple physiological signals, such as pulse signal, breathing rhythm, and real-time beat-to-beat cuffless blood pressure. All of these signals can be obtained simultaneously for detailed health detection and monitoring. The fabrication method does not involve complex expensive equipment or complicated operational processes, so it is especially suitable for the fabrication of large-area, complex flexible electronics. We believe this approach will pave the way for the application of flexible electronics in biomedical detection and health monitoring.
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Jang, Jiuk, Joohee Kim, Haein Shin, Young-Geun Park, Byung Jun Joo, Hunkyu Seo, Jong-eun Won i in. "Smart contact lens and transparent heat patch for remote monitoring and therapy of chronic ocular surface inflammation using mobiles". Science Advances 7, nr 14 (marzec 2021): eabf7194. http://dx.doi.org/10.1126/sciadv.abf7194.
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Wearable electronic devices that can monitor physiological signals of the human body to provide biomedical information have been drawing extensive interests for sustainable personal health management. Here, we report a human pilot trial of a soft, smart contact lens and a skin-attachable therapeutic device for wireless monitoring and therapy of chronic ocular surface inflammation (OSI). As a diagnostic device, this smart contact lens enables real-time measurement of the concentration of matrix metalloproteinase-9, a biomarker for OSI, in tears using a graphene field-effect transistor. As a therapeutic device, we also fabricated a stretchable and transparent heat patch attachable on the human eyelid conformably. Both diagnostic and therapeutic devices can be incorporated using a smartphone for their wireless communications, thereby achieving instantaneous diagnosis of OSI and automated hyperthermia treatments. Furthermore, in vivo tests using live animals and human subjects confirm their good biocompatibility and reliability as a noninvasive, mobile health care solution.
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Kumar, Rahul, Afaqul Zafer, P. K. Dubey, Ashok Kumar, Megha Singh, Nita Dilawar Sharma, S. K. Jaiswal i in. "Design and development of mechanical test bench for testing and calibration of multiple blood pressure measuring devices". Review of Scientific Instruments 94, nr 1 (1.01.2023): 014102. http://dx.doi.org/10.1063/5.0100958.
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Blood pressure (BP) measurement is an important physiological parameter for human health monitoring, which plays a significant role in the diagnosis of many incurable diseases. However, due to inaccuracies in the different types of BP measuring devices, the calibration of these BP measuring instruments is a major concern for a medical practitioner. Currently, these devices’ calibration, testing, and validation are performed using rigorous methods with complex clinical trials and following the available documentary standards. This article describes the design and development of an indigenous mechanical test bench (MTB) system for the testing and calibration of multiple BP devices, as per International Organization of Legal Metrology (OIML) recommended documents e.g., OIML R 16-1 and OIML R 16-2. The developed system can test and calibrate 20 BP devices, simultaneously. The traceability of the developed MTB is established by performing its calibration against the Air Piston Gauge, a national primary vacuum standard. The estimated expanded measurement uncertainty evaluated is found to be ±0.11 mmHg, which is almost one order better than the measurement uncertainty required for the test and calibration of BP measuring instruments as per standard. The MTB has successfully been used to test and calibrate several BP measuring instruments. The data of one such device is reported herein as an indicator of the performance process. The calibration of these BP measuring instruments was performed in the static mode, and the estimated expanded measurement uncertainty was found to be ±1.25 mmHg. The developed MTB system would prove to be an excellent instrument for calibration laboratories, hospitals, regulatory agencies, and other users to test and calibrate 20 BP measuring devices simultaneously and cost-effectively.
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Huang, Ji-Jer, i Zhe-Lin Cai. "Using Flexible Curved Noncontact Active Electrodes to Monitor Long-Term Heart Rate Variability". Journal of Healthcare Engineering 2020 (8.07.2020): 1–18. http://dx.doi.org/10.1155/2020/8867712.
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The purpose of this study is to utilize flexible curved noncontact active electrodes to develop a nonperception, long-term, and wireless heart rate monitoring system. This study also verified the functions and capabilities of the system and provided information on physiological parameters recorded during our tests. Our system was used in tandem with a commercially standard measurement system; both systems were used to measure ECG signals on 10 healthy subjects under the simulated home and office scenarios. We verified the R-peak measurement accuracy of our system and used T-tests to analyze the data collected by both systems; our system reached an average sensitivity value of 0.983 and an average positive predictive value of 0.991 over several different scenarios where R-peak measurements were also highly accurate. The R-R time intervals of our system were highly consistent with the standard system. The correlation coefficient calculated reached almost one, and the differences between the two systems mostly fell within the ±10 ms range. Further study of the HRV time-domain parameters under four different scenarios showed no significant differences in most HRV parameters compared to the measurements by the standard system. We also used our system to record long-term heart rate signals.
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Song, Shuren, Da Chen, Hongfei Wang, Qiuquan Guo i Wangli Yu. "Shear Mode Bulk Acoustic Viscosity Sensor for Blood Coagulation Monitoring in Oral Anticoagulant Therapy". Journal of Nanoscience and Nanotechnology 18, nr 12 (1.12.2018): 8099–104. http://dx.doi.org/10.1166/jnn.2018.16425.
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Frequent monitoring of blood coagulation status is essential for patients receiving treatment with some oral anticoagulant agents. In this paper, we present a microelectromechanical film bulk acoustic resonator for the measurement of blood coagulation parameters. The resonator was made of an aluminum nitride piezoelectric film and operated in thickness shear resonance mode with a frequency of about 2 GHz. The resonant frequency showed a linear relationship with the viscosity of the environmental liquid over the wide range of 1–25 cP, falling within the physiological range of human blood. The coagulation process of human blood was monitored by following the frequency downshift due to the viscosity change. Therefore, the frequency response was used to determine quantitatively three clinically significant parameters being the enzymatic cascade time, the coagulation time and the clot degree. As a practical demonstration, the proposed micro-resonator was applied to monitor coagulation for one month in a patient taking the oral anticoagulant, warfarin, daily. The results measured by the resonator were consistent with those of the standard coagulometer. As a result of the excellent potential for integration, miniaturization and the availability of direct digital signals, the shear mode film bulk acoustic resonator has promising application for clinical and personal coagulation monitoring.
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Montgomery, Leslie D., Richard W. Montgomery, Michael Bodo, Richard T. Mahon i Frederick J. Pearce. "Thoracic, peripheral, and cerebral volume, circulatory and pressure responses to PEEP during simulated hemorrhage in a pig model: a case study". Journal of Electrical Bioimpedance 12, nr 1 (1.01.2021): 103–16. http://dx.doi.org/10.2478/joeb-2021-0013.
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Abstract Positive end-expiratory pressure (PEEP) is a respiratory/ventilation procedure that is used to maintain or improve breathing in clinical and experimental cases that exhibit impaired lung function. Body fluid shift movement is not monitored during PEEP application in intensive care units (ICU), which would be interesting specifically in hypotensive patients. Brain injured and hypotensive patients are known to have compromised cerebral blood flow (CBF) autoregulation (AR) but currently, there is no non-invasive way to assess the risk of implementing a hypotensive resuscitation strategy and PEEP use in these patients. The advantage of electrical bioimpedance measurement is that it is noninvasive, continuous, and convenient. Since it has good time resolution, it is ideal for monitoring in intensive care units (ICU). The basis of its future use is to establish physiological correlates. In this study, we demonstrate the use of electrical bioimpedance measurement during bleeding and the use of PEEP in pig measurement. In an anesthetized pig, we performed multimodal recording on the torso and head involving electrical bioimpedance spectroscopy (EIS), fixed frequency impedance plethysmography (IPG), and bipolar (rheoencephalography – REG) measurements and processed data offline. Challenges (n=16) were PEEP, bleeding, change of SAP, and CO2 inhalation. The total measurement time was 4.12 hours. Systemic circulatory results: Bleeding caused a continuous decrease of SAP, cardiac output (CO), and increase of heart rate, temperature, shock index (SI), vegetative - Kerdo index (KI). Pulse pressure (PP) decreased only after second bleeding which coincided with loss of CBF AR. Pulmonary arterial pressure (PAP) increased during PEEP challenges as a function of time and bleeding. EIS/IPG results: Body fluid shift change was characterized by EIS-related variables. Electrical Impedance Spectroscopy was used to quantify the intravascular, interstitial, and intracellular volume changes during the application of PEEP and simulated hemorrhage. The intravascular fluid compartment was the primary source of blood during hemorrhage. PEEP produced a large fluid shift out of the intravascular compartment during the first bleeding period and continued to lose more blood following the second and third bleeding. Fixed frequency IPG was used to quantify the circulatory responses of the calf during PEEP and simulated hemorrhage. PEEP reduced the arterial blood flow into the calf and venous outflow from the calf. Head results: CBF AR was evaluated as a function of SAP change. Before bleeding, and after moderate bleeding, intracranial pressure (ICP), REG, and carotid flow pulse amplitudes (CFa) increased. This change reflected vasodilatation and active CBF AR. After additional hemorrhaging during PEEP, SAP, ICP, REG, CFa signal amplitudes decreased, indicating passive CBF AR. 1) The indicators of active AR status by modalities was the following: REG (n=9, 56 %), CFa (n=7, 44 %), and ICP (n=6, 38 %); 2) CBF reactivity was better for REG than ICP; 3) REG and ICP correlation coefficient were high (R2 = 0.81) during CBF AR active status; 4) PRx and REGx reflected active CBF AR status. CBF AR monitoring with REG offers safety for patients by preventing decreased CBF and secondary brain injury. We used different types of bioimpedance instrumentation to identify physiologic responses in the different parts of the body (that have not been discussed before) and how the peripheral responses ultimately lead to decreased cardiac output and changes in the head. These bioimpedance methods can improve ICU monitoring, increase the adequacy of therapy, and decrease mortality and morbidity.
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Wang, Zixia, Shuai Zha, Baoxian Yu, Pengbin Chen, Zhiqiang Pang i Han Zhang. "Sleep Staging Using Noncontact-Measured Vital Signs". Journal of Healthcare Engineering 2022 (8.07.2022): 1–11. http://dx.doi.org/10.1155/2022/2016598.
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As a physiological phenomenon, sleep takes up approximately 30% of human life and significantly affects people’s quality of life. To assess the quality of night sleep, polysomnography (PSG) has been recognized as the gold standard for sleep staging. The drawbacks of such a clinical device, however, are obvious, since PSG limits the patient’s mobility during the night, which is inconvenient for in-home monitoring. In this paper, a noncontact vital signs monitoring system using the piezoelectric sensors is deployed. Using the so-designed noncontact sensing system, heartbeat interval (HI), respiratory interval (RI), and body movements (BM) are separated and recorded, from which a new dimension of vital signs, referred to as the coordination of heartbeat interval and respiratory interval (CHR), is obtained. By extracting both the independent features of HI, RI, and BM and the coordinated features of CHR in different timescales, Wake-REM-NREM sleep staging is performed, and a postprocessing of staging fusion algorithm is proposed to refine the accuracy of classification. A total of 17 all-night recordings of noncontact measurement simultaneous with PSG from 10 healthy subjects were examined, and the leave-one-out cross-validation was adopted to assess the performance of Wake-REM-NREM sleep staging. Taking the gold standard of PSG as reference, numerical results show that the proposed sleep staging achieves an averaged accuracy and Cohen’s Kappa index of 82.42% and 0.63, respectively, and performs robust to subjects suffering from sleep-disordered breathing.
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Atkins, Ian K., Nigel B. Cook, Mario R. Mondaca i Christopher Y. Choi. "Continuous Respiration Rate Measurement of Heat-Stressed Dairy Cows and Relation to Environment, Body Temperature, and Lying Time". Transactions of the ASABE 61, nr 5 (2018): 1475–85. http://dx.doi.org/10.13031/trans.12451.
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Abstract. This study uses a continuously sampling sensor to document the respiration rate dynamics of lactating dairy cows under conditions of heat stress. Previously available respiration rate data on lactating dairy cows had primarily been generated by manually counting flank movements at discrete points in time, typically several times per day. Continuous measurements provide much higher-resolution data over time. The primary objective of this study was to analyze these continuous respiration rate measurements in relation to ambient conditions, body temperature, lying time, and time of day. Better understanding continuous responses to heat stress may help synchronize cooling system operation to the cows’ need for heat stress relief. For 19 days during a summer season in Wisconsin, eight lactating Holstein cows were equipped with sensors designed to detect the abdominal expansion associated with breathing. An algorithm was developed to derive respiration rate from each sensor’s signal. To validate the accuracy of the sensor and algorithms, measurements from the sensor were compared to respiration rate measurements taken via visual observation. Overall, variation in continuously measured respiration rate corresponded to changes in temperature-humidity index (THI) and body temperature. However, respiration rate and body temperature also remained elevated at night despite decreasing THI. Keywords: Dairy cow, Heat stress, Physiological monitoring, Respiration rate, Telemetry, Wearable.
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Ahmad, Zulkifli, Mohd Najeb Jamaludin i Kamaruzaman Soeed. "An effect of physical exercise-induced fatigue on the vital sign parameters: A preliminary study". Malaysian Journal of Fundamental and Applied Sciences 15, nr 2 (16.04.2019): 173–77. http://dx.doi.org/10.11113/mjfas.v15n2.1287.
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Vital sign monitoring is an important body measurement to identify health condition and diagnose any disease and illness. In sports, physical exercise will contribute to the changes of the physiological systems, specifically for the vital signs. Therefore, the objective of this study was to determine the effect of physical fatigue exercise on the vital sign parameters. This is significant for the fitness identification and prediction of each individual when performing an exercise. Five male subjects with no history of injuries and random BMI were selected from students of biomedical engineering, Universiti Teknologi Malaysia. Based on the relationship between physical movement and physiology, the parameters considered were heart rate, blood pressure, and body temperature. Subjects were required to run on the treadmill at an initial speed of 4 km/h with an increase of 1 km/h at every 2 minutes interval. The effect of exercise was marked according to the fatigue protocol where the subject was induced to the maximum condition of performance. All parameters were measured twice, for pre and post exercise-induced protocol. The analysis of relationship of each parameter between pre and post fatigue was p<0.05. The results revealed that the heart rate and gap between blood pressure’s systolic and diastolic were greater for all categories except underweight, where the systolic blood pressure dropped to below 100mmHg at the end of exercise. Also, the body temperature was slightly declined to balance the thermoregulatory system with sweating. Hence, the vigorous physical movement could contribute to the active physiological system based on body metabolism. Heart rate and blood pressure presented significant effects from the fatiguing exercise whereas the body temperature did not indicate any distinguishable impact. The results presented might act as the basis of reference for physical exercise by monitoring the vital sign parameters.
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Ocvirk, Gregor, Martin Hajnsek, Ralph Gillen, Arnfried Guenther, Gernot Hochmuth, Ulrike Kamecke, Karl-Heinz Koelker i in. "The Clinical Research Tool: A High-Performance Microdialysis-Based System for Reliably Measuring Interstitial Fluid Glucose Concentration". Journal of Diabetes Science and Technology 3, nr 3 (maj 2009): 468–77. http://dx.doi.org/10.1177/193229680900300310.
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Background: A novel microdialysis-based continuous glucose monitoring system, the so-called Clinical Research Tool (CRT), is presented. The CRT was designed exclusively for investigational use to offer high analytical accuracy and reliability. The CRT was built to avoid signal artifacts due to catheter clogging, flow obstruction by air bubbles, and flow variation caused by inconstant pumping. For differentiation between physiological events and system artifacts, the sensor current, counter electrode and polarization voltage, battery voltage, sensor temperature, and flow rate are recorded at a rate of 1 Hz. Method: In vitro characterization with buffered glucose solutions (cglucose = 0 − 26 × 10−3 mol liter−1) over 120 h yielded a mean absolute relative error (MARE) of 2.9 ± 0.9% and a recorded mean flow rate of 330 ± 48 nl/min with periodic flow rate variation amounting to 24 ± 7%. The first 120 h in vivo testing was conducted with five type 1 diabetes subjects wearing two systems each. A mean flow rate of 350 ± 59 nl/min and a periodic variation of 22 ± 6% were recorded. Results: Utilizing 3 blood glucose measurements per day and a physical lag time of 1980 s, retrospective calibration of the 10 in vivo experiments yielded a MARE value of 12.4 ± 5.7. Clarke error grid analysis resulted in 81.0%, 16.6%, 0.8%, 1.6%, and 0% in regions A, B, C, D, and E, respectively. Conclusion: The CRT demonstrates exceptional reliability of system operation and very good measurement performance. The ability to differentiate between artifacts and physiological effects suggests the use of the CRT as a reference tool in clinical investigations.
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Barak, J., S. Einav, A. Tadmor, B. Vidne i W. G. Austen. "The Effect of Colloid Osmotic Pressure on the Survival of Sheep following Cardiac Surgery". International Journal of Artificial Organs 12, nr 1 (styczeń 1989): 47–50. http://dx.doi.org/10.1177/039139888901200108.
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The occurrence of late complications in implanted cardiac prosthetic valves has emphasized the need for the development of an animal model in which these complications are reproducible. Sheep constitute an excellent model for chronical and pathological studies of prosthetic devices. In our experience, survival of sheep following implantation of prosthetic valves is closely related to postoperative serum colloid osmotic pressure (C.O.P.). The normal range as measured in 28 healthy sheep was 16.67 ± 0.55 mm Hg. A protocol was developed to maintain the colloid hydrostatic pressure gradient (C.H.P.G.) as close as possible to the normal physiological range, and to delay the extubation until the C.O.P. was within this range, and the C.H.P.G. > 7mm Hg. Using the above protocol, a new tri-leaflet Polyurethane valve was inserted into eight, five to seven month old sheep in place of the mitral and tricuspidal valves. One hour after terminating the extacorporeal circuit, the C.O.P. was measured at 13.10 ± 0.96; but within five to six hours, it rose to 17.1 ± 1.1. During the same period, the C.H.P.G. increased from 3.02 ± 0.96 to 7.6 ± 0.50 mm Hg. The postoperative period was uneventful, and all animals survived. We have thus concluded that the routine measurement and monitoring of C.O.P. constitutes a guide of great clinical importance.
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Zhang, Hengjie, Ye Qiu, Sihang Yu, Chen Ding, Jiahui Hu, Hangcheng Qi, Ye Tian, Zheng Zhang, Aiping Liu i Huaping Wu. "Wearable microfluidic patch with integrated capillary valves and pumps for sweat management and multiple biomarker analysis". Biomicrofluidics 16, nr 4 (lipiec 2022): 044104. http://dx.doi.org/10.1063/5.0092084.
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Wearable sweat sensors are essential for providing insight into human physiological health. The currently developed microfluidic sweat sensors have demonstrated the function of collecting and storing sweat. However, they detect more average concentrations of substances based on time periods, which leads to the fact that in situ real-time measurement for multiple biomarkers remains a grand challenge. Here, we propose a wearable epidermal microfluidic patch with integrated microfluidic pumps and micro-valves for accelerated and continuous collection of the sweat, where the micro-pumps ensure the complete separation of old and new sweat for real-time detection of real concentration of biomarkers in sweat. The biomarker concentration at different time periods is detected by introducing a burst valve, which is used to assist in the analysis of the real-time detection. A quantitative relationship between the minimum burst pressure difference required for sequential collection and the size of the microchannel structure is established to overcome the effects of additional resistance at the gas–liquid interface. Additionally, the sensing modules, including sodium ion, chlorine ion, glucose, and pH level in sweat, are integrated into the patch to realize in situ, real-time detection of multiple biomarkers in the human sweat, decoding the correlation between changes in substance concentrations and physiological conditions. This work provides a unique and simplifying strategy for developing wearable sweat sensors for potential applications in health monitoring and disease diagnostics.
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Isupov, Igor, i Rimma Zatrudina. "Electronic Module for Photoplethysmography аnd Pulse Oximetry". Natural Systems and Resources, nr 3 (grudzień 2018): 15–21. http://dx.doi.org/10.15688/nsr.jvolsu.2018.3.2.
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Methods of pulse oximetry and photoplethysmography are widely used in clinical medicine and practice of biomedical research outside the clinic. The advantages of the method are high efficiency of preparation for the diagnostic procedure, non-invasive, complete safety for health. The method provides the possibility of unlimited long - term monitoring of the dynamics of saturation and desaturation of hemoglobin. In combination with the above, subject to the qualitative registration of photoplethysmograms, the method allows the calculation and analysis of a number of indicators of peripheral blood circulation: the total pulse blood flow to the study region, the tone of arterial vessels of different diameters, the state of capillary blood flow. Most modern foreign models of pulse oximeters are integrated devices that provide measurement of a very limited set of physiological parameters: the percentage of hemoglobin oxygen saturation and pulse rate. The range of pulse oximeters containing the interface with the personal computer and providing operational calculation of indicators of peripheral photoplethysmograms is small. Such devices have a fairlyhigh cost and are not portable. The development of domestic integrated electronic devices is extremely relevant, allowing along with obtaining information about blood oxygenation to perform continuous monitoring of peripheral blood circulation. The authors developed an electronic module that provides long-term registration of photoplethysmograms in the infrared and red areas of the light spectrum. The electronic module is made exclusively with the use of domestic active radio elements – discrete semiconductor devices and integrated circuits. The device was developed in full compliance with the import substitution policy pursued by the President and the Government of the Russian Federation. The advantage of the device is the "open architecture" of the electronic circuit, which provides four analog signals suitable for further digitization. The signals contain information about pulsating and non-pulsating components of the optical density of biological tissue in the infrared and red ranges of the spectrum. The device has an electronic filter of mains interference. Tests of the device demonstrated high quality of photoplethysmograms. This makes it possible tosuccessfullyuse the device for studies of hemoglobin oxygenation and peripheral hemodynamics.
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Valenza, Gaetano. "Biomedical Signal Processing: The Cornerstone of Artificial Intelligence in Healthcare Wearables". Biomedical Materials & Devices, 23.11.2022. http://dx.doi.org/10.1007/s44174-022-00051-y.
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AbstractHealth sensors and remote measurement tools have saved lives through the possibility of continuous monitoring and intervention tools, and over the years their use has expanded to non-medical areas such as fitness and perceived well-being. This expansion has led to unprecedented data collection, especially since biomedical sensors are now ubiquitous in everyday devices such as smartwatches and smartphones. While these devices can be disruptive research tools and even clinical tools, they pose technological and socio-economic challenges that can limit their impact. Here, we highlight these challenges, including the use of proxies for clinical reference measurements, uncertainties resulting from the presence of noise, complexity of physiological systems, and statistical methods used for data interpretation.
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Iqbal, Talha, Adnan Elahi, Sandra Ganly, William Wijns i Atif Shahzad. "Photoplethysmography-Based Respiratory Rate Estimation Algorithm for Health Monitoring Applications". Journal of Medical and Biological Engineering, 7.04.2022. http://dx.doi.org/10.1007/s40846-022-00700-z.
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Abstract Purpose Respiratory rate can provide auxiliary information on the physiological changes within the human body, such as physical and emotional stress. In a clinical setup, the abnormal respiratory rate can be indicative of the deterioration of the patient's condition. Most of the existing algorithms for the estimation of respiratory rate using photoplethysmography (PPG) are sensitive to external noise and may require the selection of certain algorithm-specific parameters, through the trial-and-error method. Methods This paper proposes a new algorithm to estimate the respiratory rate using a photoplethysmography sensor signal for health monitoring. The algorithm is resistant to signal loss and can handle low-quality signals from the sensor. It combines selective windowing, preprocessing and signal conditioning, modified Welch filtering and postprocessing to achieve high accuracy and robustness to noise. Results The Mean Absolute Error and the Root Mean Square Error of the proposed algorithm, with the optimal signal window size, are determined to be 2.05 breaths count per minute and 2.47 breaths count per minute, respectively, when tested on a publicly available dataset. These results present a significant improvement in accuracy over previously reported methods. The proposed algorithm achieved comparable results to the existing algorithms in the literature on the BIDMC dataset (containing data of 53 subjects, each recorded for 8 min) for other signal window sizes. Conclusion The results endorse that integration of the proposed algorithm to a commercially available pulse oximetry device would expand its functionality from the measurement of oxygen saturation level and heart rate to the continuous measurement of the respiratory rate with good efficiency at home and in a clinical setting.
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Lu, Yang, Qingqing Zhou i Lin Xu. "Non-Invasive Electrochemical Biosensors for TNF-α Cytokines Detection in Body Fluids". Frontiers in Bioengineering and Biotechnology 9 (21.09.2021). http://dx.doi.org/10.3389/fbioe.2021.701045.
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The measurement of pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-α), which is an important indicator of the inflammatory process, has received increasing attention recently because it is easy to extract from body fluid and serves as an early sign of a serious systemic inflammatory disease. Developing fast and simple detection methods to quantify the concentration of TNF-α is essential. Saliva, tears, and urine, which can easily be sampled in a non-invasive way, are considered to be important matrices for monitoring and assessing the physiological status of humans; importantly, they also provide an ideal window for monitoring the concentration of TNF-α. As a fast, accurate, inexpensive, portable, and scalable method, electrochemical biosensors are very promising for biomarker detection in matrices obtained in a non-invasive manner. This review summarises and compares the electrochemical biosensors for the detection of TNF-α in a non-invasive manner and highlights recent advances and future prospects in developing high-performance electrochemical platforms for noninvasive measurement of TNF-α.
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García-López, Irene, Renard Xaviero Adhi Pramono i Esther Rodriguez-Villegas. "Artifacts classification and apnea events detection in neck photoplethysmography signals". Medical & Biological Engineering & Computing, 17.10.2022. http://dx.doi.org/10.1007/s11517-022-02666-1.
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AbstractThe novel pulse oximetry measurement site of the neck is a promising location for multi-modal physiological monitoring. Specifically, in the context of respiratory monitoring, in which it is important to have direct information about airflow. The neck makes this possible, in contrast to common photoplethysmography (PPG) sensing sites. However, this PPG signal is susceptible to artifacts that critically impair the signal quality. To fully exploit neck PPG for reliable physiological parameters extraction and apneas monitoring, this paper aims to develop two classification algorithms for artifacts and apnea detection. Features from the time, correlogram, and frequency domains were extracted. Two SVM classifiers with RBF kernels were trained for different window (W) lengths and thresholds (Thd) of corruption. For artifacts classification, the maximum performance was attained for the parameters combination of [W = 6s-Thd= 20%], with an average accuracy= 85.84%(ACC), sensitivity= 85.43%(SE) and specificity= 86.26%(SP). For apnea detection, the model [W = 10s-Thd= 50%] maximized all the performance metrics significantly (ACC= 88.25%, SE= 89.03%, SP= 87.42%). The findings of this proof of concept are significant for denoising novel neck PPG signals, and demonstrate, for the first time, that it is possible to promptly detect apnea events from neck PPG signals in an instantaneous manner. This could make a big impact in crucial real-time applications, like devices to prevent sudden-unexpected-death-in-epilepsy (SUDEP).
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Beh, Win-Ken, Yu-Chia Yang, Yi-Cheng Lo, Yun-Chieh Lee i An-Yeu(Andy) Wu. "Machine-Aided PPG Signal Quality Assessment(SQA) for Multi-mode Physiological Signal Monitoring". ACM Transactions on Computing for Healthcare, 13.03.2023. http://dx.doi.org/10.1145/3587256.
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Photoplethysmography (PPG) is a non-invasive technique for recording human vital signs. PPG is normally recorded by wearable devices that are prone to artifacts. This results in signal corruption that decreases measurement accuracy. Thus, a signal quality assessment (SQA) system is essential in obtaining reliable measurements. Conventionally, SQA is mainly driven by human-knowledge and supervised through expert’s annotations. However, they are not tailored for the particularities of the domain applications. Hence, we propose a machine-aided signal quality assessment (SQA) framework that generates respective quality criteria for applications. By using the proposed approach, quality criteria can be easily trained for different applications. Then, quality assessment can be applied to several PPG-based physiological signals telemonitoring. Compared with conventional approaches, the proposed system has a higher rejection rate for high-error signals, and a lower mean absolute error is achieved when estimating heart rate (-3.06BPM), determining respiration rate (-1.36BPM), and predicting hypertension (+24%). The proposed method enhances accuracy in monitoring physiological signals and thus suitable for healthcare applications.
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Ou, Tzu-Ming, Wei-Wen Hu, Chia-Hung Chang, Chia-Chin Hsu i Chih-Hsuan Wang. "Experimental demonstration of noncontact vital-sign measurement using pulse radar". Technology and Health Care, 28.04.2022, 1–9. http://dx.doi.org/10.3233/thc-thc220022.
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BACKGROUD: Recently, monitoring the vital-sign with the noncontact method is a popular technology. OBJECTIVE: In this work, we present a fully pulse radar system including front-end sensing and back-end data processing. A series of ultra-wide band sensing pulses is generated and radiated to detect the subject’s chest vibration which in turn obtains the required vital-sign signals. METHODS: An artificial plywood with 3 centimeter thickness is placed between a transmitting/receiving antenna of the radar and subject to demonstrate the characteristic of noncontact sensing. The firmware and digital signal processing are also presented in this paper to optimize physiological data quality. RESULTS: The experimental results show that the continuous heart rate and breathing rate can be monitored by this customized system radar module. CONCLUSION: A fully customized ultra-wide band radar for vital-sign application is presented. The radar system plan with wall parameter is also incorporated into the design consideration to meet the FCC requirement and SNR.
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Cui, Liu, Jing Huang, Yanjiao Shi i Hongzhe Yang. "MOTILITY OF THE UNPREPARED INTESTINAL TRACT IN HEALTHY HUMANS AND PATIENTS WITH SLOW TRANSIT CONSTIPATION REVEALED BY USING MICRO-ELECTRONIC CAPSULE". Biomedical Engineering: Applications, Basis and Communications, 20.10.2021. http://dx.doi.org/10.4015/s1016237221500538.
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Slow transit constipation (STC) is usually accompanied by intestinal motility abnormalities. Although conventional anorectal manometry could record the pressure in the colon, most patients need preparation of intestinal tract. The intervention of catheter for monitoring the intestinal pressure also affects the clinical measurement. The pressure data collected by the conventional anorectal manometry cannot fully characterize the dynamic characteristics of the intestine. Thus, we aimed to obtain colonic pressure data under normal physiological conditions. Utilizing these data, we analyze the difference of colonic motility parameters between healthy control and patients with STC. A micro-electronic capsule made by ourselves was used to gather the subjects’ intestinal pressure in their daily life. Several intestinal motility parameters were calculated from the pressure profile. The average energy of colonic pressure data in the STC group is higher than the healthy control group (HC: 259.95 vs. STC: 821.28). But the STC group has a lower average complexity of colonic motility (HC: 0.80 vs. STC: 0.64). About 81.25% of the colonic data from patients with STC could be identified by using slow transit constipation (SVM) classifier. Compared with health control, most colonic parameters of patients with STC are higher under the normal physiological conditions, but the complexity of colonic motility is lower in the STC group. The correct rate of colonic pressure recognition in the STC group is more than 80% by using SVM classifier.
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Fritiss, Mohamed zied, Patrick Poulichet, Hakim Takhedmit, Laurent Lanquetin, Stephane Protat, Patrice Vallade, Elodie Richalot i Olivier Francais. "Design and characterization of a broadband PCB-based coaxial sensor for permittivity screening in skin cancer detection applications". Measurement Science and Technology, 24.07.2023. http://dx.doi.org/10.1088/1361-6501/ace9f1.
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Abstract Broadband dielectric spectroscopy is nowadays considered as a useful non-destructive diagnostic tool for biomedical applications like glucose monitoring, hydration level measurement, and cancer tissue examination. Depending on their composition and physiological state, biological tissues have different dielectric characteristics and studies on melanoma have revealed that the lesion site's skin permittivity degree changes depending on the malignancy of the lesion. The complex permittivity of suspicious areas must therefore be imaged with spatial resolution consistent with the small dimensions of these surfaces in order to correctly detect and characterize the lesion site. The variety of skin qualities for various individuals and physiological situations (such as temperature, humidity), however, makes it difficult to build a sensitive sensor capable of constantly detecting minor fluctuations in permittivity. In order to identify various types of cancers in their early stages with a good agreement between simulated and measured results, this work proposes the design of a unique microwave sensor that can precisely detect alterations in cutaneous permittivity between 1 and 6 GHz.
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Reséndiz, Mariel, Julie Fontecave-Jallon i Bertrand Rivet. "Hidden Markov model in nonnegative matrix factorization for fetal heart rate estimation using physiological priors". Physiological Measurement, 16.09.2022. http://dx.doi.org/10.1088/1361-6579/ac92bf.
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Abstract Objective Fetal heart rate (fHR) analysis remains the most common technique for detecting fetal distress when monitoring the fetal well-being during labor. If cardiotocography (CTG) is nowadays the non-invasive clinical reference technique for fHR measurement, it suffers from several drawbacks, hence an increasing interest towards alternative technologies, especially around abdominal ECG (aECG). Approach An original solution, using a single abdominal lead, was recently proposed to address both the feasibility in clinical routine and the challenging detection of temporal events when facing interfered signals from real life conditions. Based on a specification of the non-negative matrix factorization (NMF) algorithm, it exploits the semi-periodicity of fetal electrocardiogram (fECG) for fHR estimation. However, this method assumes temporal independence and therefore does not consider the continuity property of fHR values. It is thus proposed to add to the NMF framework a hidden Markov model (HMM) to include physiological information about fHR temporal evolution. Under a statistical setting, constraints have been added by accommodating regularization terms through Bayesian priors. Main results The proposed method is evaluated on 23 real aECG signals from a new clinical database, according to CTG reference, and compared with the original NMF-only algorithm. The new proposed method improves performance, with an agreement with CTG increasing from 71% to 80%. Significance This highlights the interest of a better modelization of the fHR characteristics for a more robust estimation.
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Bjørdalsbakke, Nikolai L., Jacob Sturdy, Emma M. L. Ingeström i Leif R. Hellevik. "Monitoring variability in parameter estimates for lumped parameter models of the systemic circulation using longitudinal hemodynamic measurements". BioMedical Engineering OnLine 22, nr 1 (13.04.2023). http://dx.doi.org/10.1186/s12938-023-01086-y.
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Abstract Background Physics-based cardiovascular models are only recently being considered for disease diagnosis or prognosis in clinical settings. These models depend on parameters representing the physical and physiological properties of the modeled system. Personalizing these parameters may give insight into the specific state of the individual and etiology of disease. We applied a relatively fast model optimization scheme based on common local optimization methods to two model formulations of the left ventricle and systemic circulation. One closed-loop model and one open-loop model were applied. Intermittently collected hemodynamic data from an exercise motivation study were used to personalize these models for data from 25 participants. The hemodynamic data were collected for each participant at the start, middle and end of the trial. We constructed two data sets for the participants, both consisting of systolic and diastolic brachial pressure, stroke volume, and left-ventricular outflow tract velocity traces paired with either the finger arterial pressure waveform or the carotid pressure waveform. Results We examined the feasibility of separating parameter estimates for the individual from population estimates by assessing the variability of estimates using the interquartile range. We found that the estimated parameter values were similar for the two model formulations, but that the systemic arterial compliance was significantly different ($$p < 10^{-6}$$ p < 10 - 6 ) depending on choice of pressure waveform. The estimates of systemic arterial compliance were on average higher when using the finger artery pressure waveform as compared to the carotid waveform. Conclusions We found that for the majority of participants, the variability of parameter estimates for a given participant on any measurement day was lower than the variability both across all measurement days combined for one participant, and for the population. This indicates that it is possible to identify individuals from the population, and that we can distinguish different measurement days for the individual participant by parameter values using the presented optimization method.
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Adão Martins, Neusa R., Simon Annaheim, Christina M. Spengler i René M. Rossi. "Fatigue Monitoring Through Wearables: A State-of-the-Art Review". Frontiers in Physiology 12 (15.12.2021). http://dx.doi.org/10.3389/fphys.2021.790292.
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The objective measurement of fatigue is of critical relevance in areas such as occupational health and safety as fatigue impairs cognitive and motor performance, thus reducing productivity and increasing the risk of injury. Wearable systems represent highly promising solutions for fatigue monitoring as they enable continuous, long-term monitoring of biomedical signals in unattended settings, with the required comfort and non-intrusiveness. This is a p rerequisite for the development of accurate models for fatigue monitoring in real-time. However, monitoring fatigue through wearable devices imposes unique challenges. To provide an overview of the current state-of-the-art in monitoring variables associated with fatigue via wearables and to detect potential gaps and pitfalls in current knowledge, a systematic review was performed. The Scopus and PubMed databases were searched for articles published in English since 2015, having the terms “fatigue,” “drowsiness,” “vigilance,” or “alertness” in the title, and proposing wearable device-based systems for non-invasive fatigue quantification. Of the 612 retrieved articles, 60 satisfied the inclusion criteria. Included studies were mainly of short duration and conducted in laboratory settings. In general, researchers developed fatigue models based on motion (MOT), electroencephalogram (EEG), photoplethysmogram (PPG), electrocardiogram (ECG), galvanic skin response (GSR), electromyogram (EMG), skin temperature (Tsk), eye movement (EYE), and respiratory (RES) data acquired by wearable devices available in the market. Supervised machine learning models, and more specifically, binary classification models, are predominant among the proposed fatigue quantification approaches. These models were considered to perform very well in detecting fatigue, however, little effort was made to ensure the use of high-quality data during model development. Together, the findings of this review reveal that methodological limitations have hindered the generalizability and real-world applicability of most of the proposed fatigue models. Considerably more work is needed to fully explore the potential of wearables for fatigue quantification as well as to better understand the relationship between fatigue and changes in physiological variables.
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Chung, Taerin, Hao Wang i Haogang Cai. "Dielectric metasurfaces for next-generation optical biosensing: a comparison with plasmonic sensing". Nanotechnology, 23.06.2023. http://dx.doi.org/10.1088/1361-6528/ace117.
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Abstract In the past decades, nanophotonic biosensors have been extended from the extensively studied plasmonic platforms to dielectric metasurfaces. Instead of plasmonic resonance, dielectric metasurfaces are based on Mie resonance, which provide comparable sensitivity with superior resonance bandwidth, Q factor, and figure-of-merit. Although the plasmonic photothermal effect is beneficial in many biomedical applications, it is a fundamental limitation for biosensing. Dielectric metasurfaces solve the Ohmic loss and heating problems, providing better repeatability, stability, and bio-compatibility. We review the high-Q resonances based on various physical phenomena tailored by meta-atom geometric designs, and compare dielectric and plasmonic metasurfaces in refractometric, surface-enhanced, and chirality sensing for various biomedical and diagnostic applications. Departing from conventional spectral shift measurement using spectrometers, imaging-based and spectrometer-less biosensing are highlighted, including single-wavelength refractometric barcoding, surface-enhanced molecular fingerprinting, and integrated visual reporting. These unique modalities enabled by dielectric metasurfaces point to two important research directions. On the one hand, hyperspectral imaging provides massive information for smart data processing, which not only achieve better biomolecular sensing performance than conventional ensemble averaging, but also enable real-time monitoring of cellular or microbial behaviour in physiological conditions. On the other hand, a single metasurface can integrate both functions of sensing and optical output engineering, using single-wavelength or broadband light sources, which provides simple, fast, compact and cost-effective solutions. Finally, we provide perspectives in future development on metasurface materials, configurations, nanofabrication, surface modification and system integration, towards next-generation optical biosensing for ultra-sensitive, portable/wearable, lab-on-a-chip, point-of-care, multiplexed and scalable applications.
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Dalla Gasperina, Stefano, Valeria Longatelli, Francesco Braghin, Alessandra Pedrocchi i Marta Gandolla. "Development and Electromyographic Validation of a Compliant Human-Robot Interaction Controller for Cooperative and Personalized Neurorehabilitation". Frontiers in Neurorobotics 15 (18.01.2022). http://dx.doi.org/10.3389/fnbot.2021.734130.
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BackgroundAppropriate training modalities for post-stroke upper-limb rehabilitation are key features for effective recovery after the acute event. This study presents a cooperative control framework that promotes compliant motion and implements a variety of high-level rehabilitation modalities with a unified low-level explicit impedance control law. The core idea is that we can change the haptic behavior perceived by a human when interacting with the rehabilitation robot by tuning three impedance control parameters.MethodsThe presented control law is based on an impedance controller with direct torque measurement, provided with positive-feedback compensation terms for disturbances rejection and gravity compensation. We developed an elbow flexion-extension experimental setup as a platform to validate the performance of the proposed controller to promote the desired high-level behavior. The controller was first characterized through experimental trials regarding joint transparency, torque, and impedance tracking accuracy. Then, to validate if the controller could effectively render different physical human-robot interaction according to the selected rehabilitation modalities, we conducted tests on 14 healthy volunteers and measured their muscular voluntary effort through surface electromyography (sEMG). The experiments consisted of one degree-of-freedom elbow flexion/extension movements, executed under six high-level modalities, characterized by different levels of (i) corrective assistance, (ii) weight counterbalance assistance, and (iii) resistance.ResultsThe unified controller demonstrated suitability to promote good transparency and render both compliant and stiff behavior at the joint. We demonstrated through electromyographic monitoring that a proper combination of stiffness, damping, and weight assistance could induce different user participation levels, render different physical human-robot interaction, and potentially promote different rehabilitation training modalities.ConclusionWe proved that the proposed control framework could render a wide variety of physical human-robot interaction, helping the user to accomplish the task while exploiting physiological muscular activation patterns. The reported results confirmed that the control scheme could induce different levels of the subject's participation, potentially applicable to the clinical practice to adapt the rehabilitation treatment to the subject's progress. Further investigation is needed to validate the presented approach to neurological patients.
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Miyazawa, AA, D. Keene, M. Johal, AD Arnold, NS Peters, P. Kanagaratnam, NWF Linton i in. "A method for accurately and dynamically optimising pacemaker atrio-ventricular delay timing using implantable physiological biomarkers". EP Europace 23, Supplement_3 (1.05.2021). http://dx.doi.org/10.1093/europace/euab116.464.
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Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): BRAVO trial: BHF SP/10/002/28189, FS/10/038, FS/11/92/29122, FS/13/44/30291) National Institute for Health Research Imperial Biomedical Research Centre. HOPE-HF trial: British Heart Foundation (CS/15/3/31405, FS/13/44/30291, FS/15/53/31615, FS/14/27/30752, FS/10/038). Introduction The optimal atrioventricular (AV) delay for implantable cardiac devices can be derived by echocardiography or beat-by-beat blood pressure measurements. However, both of these approaches are labour intensive and neither could be incorporated into an implantable cardiac device for frequent repeated optimisations. Laser Doppler perfusion monitoring (LDPM) measures blood flow through tissue. LDPM has been miniaturised ready to be incorporated into future implantable cardiac devices. Purpose We studied if LDPM is a clinically reliable alternative method to blood-pressure measurements to determine optimal AV delay. Methods Data from 58 patients undergoing 94 clinical AVD optimisations using LDPM and simultaneous non-invasive beat-by-beat blood pressure was obtained. The optimal AV delay for each method and for each optimisation was determined using a curve of haemodynamic response to switching from AAI (reference state) to DDD (test state) at a series of AV delays (40, 80, 120, 160, 200, 240 ms). We then compared the derived optimal AV delays between the two measurement approaches. We also assessed the impact of the paced heart-rate on agreement between laser Doppler and Blood-Pressure derived optimal AV delays. Results The AV delay derived using LDPM was not clinically significant different from that derived by blood pressure changes. The median difference was -9ms (IQR -26 to 7, p = 0.05). Variability between the two methods was low (median absolute deviation 17ms). Optimisations performed at higher heart-rates resulted in a non-significant smaller difference between the LDPM and blood-pressure derived AV delays (median absolute deviation 12 vs 22 ms, p = 0.11). Conclusions Optimal AVDs derived from non-invasive blood-pressure or laser Doppler perfusion methods are clinically equivalent. The addition of laser Doppler to future implantable cardiac devices may enable devices to dynamically and reliably optimise AV delays. Abstract Figure 1
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Palma-Florez, Sujey, Adrián López-Canosa, Francisco Moralez-Zavala, Oscar Castaño, Marcelo J. Kogan, Josep Samitier, Anna Lagunas i Mònica Mir. "BBB-on-a-chip with integrated micro-TEER for permeability evaluation of multi-functionalized gold nanorods against Alzheimer’s disease". Journal of Nanobiotechnology 21, nr 1 (29.03.2023). http://dx.doi.org/10.1186/s12951-023-01798-2.
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Abstract Background The lack of predictive models that mimic the blood–brain barrier (BBB) hinders the development of effective drugs for neurodegenerative diseases. Animal models behave differently from humans, are expensive and have ethical constraints. Organ-on-a-chip (OoC) platforms offer several advantages to resembling physiological and pathological conditions in a versatile, reproducible, and animal-free manner. In addition, OoC give us the possibility to incorporate sensors to determine cell culture features such as trans-endothelial electrical resistance (TEER). Here, we developed a BBB-on-a-chip (BBB-oC) platform with a TEER measurement system in close distance to the barrier used for the first time for the evaluation of the permeability performance of targeted gold nanorods for theranostics of Alzheimer’s disease. GNR-PEG-Ang2/D1 is a therapeutic nanosystem previously developed by us consisting of gold nanorods (GNR) functionalized with polyethylene glycol (PEG), angiopep-2 peptide (Ang2) to overcome the BBB and the D1 peptide as beta amyloid fibrillation inhibitor, finally obtaining GNR-PEG-Ang2/D1 which showed to be useful for disaggregation of the amyloid in in vitro and in vivo models. In this work, we evaluated its cytotoxicity, permeability, and some indications of its impact on the brain endothelium by employing an animal-free device based on neurovascular human cells. Results In this work, we fabricated a BBB-oC with human astrocytes, pericytes and endothelial cells and a TEER measuring system (TEER-BBB-oC) integrated at a micrometric distance of the endothelial barrier. The characterization displayed a neurovascular network and the expression of tight junctions in the endothelium. We produced GNR-PEG-Ang2/D1 and determined its non-cytotoxic range (0.05–0.4 nM) for plated cells included in the BBB-oC and confirmed its harmless effect at the highest concentration (0.4 nM) in the microfluidic device. The permeability assays revealed that GNR-PEG-Ang2/D1 cross the BBB and this entry is facilitated by Ang2 peptide. Parallel to the permeability analysis of GNR-PEG-Ang2/D1, an interesting behavior of the TJs expression was observed after its administration probably related to the ligands on the nanoparticle surface. Conclusions BBB-oC with a novel TEER integrated setup which allow a correct read-out and cell imaging monitoring was proven as a functional and throughput platform to evaluate the brain permeability performance of nanotherapeutics in a physiological environment with human cells, putting forward a viable alternative to animal experimentation.