Electronic Transducer Research Articles

Invasive validation of central blood pressure measurements using a suprasystolic monitor

Abstract Interest in the assessment of Central Blood Pressure (cBP) is steadily growing since it is a better predictor of myocardial infarction, stroke, or death than Peripheral Blood Pressure (pBP). However, pBP remains the first line for the diagnosis of hypertension (HTN) due to the ease and speed of the measurement. We sought to validate a new method to estimate cBP from brachial sphygmomanometer measurements. We estimated cBP using a sphygmomanometer that can record, after conventional pBP measurements, the pressure in the cuff maintained at a constant suprasystolic pressure. cBP is calculated using a method based on applying a physics-based model of the left subclavian artery to the brachial arterial branch to the suprasystolic brachial artery pressure waveforms. We compared this noninvasive estimated cBP to an invasive gold-standard measurement during cardiac catheterization. After clinically indicated cardiac catheterization requiring a haemodynamic assessment of a moderate coronary artery stenosis by Fractional Flow Reserve (FFR), the wire that incorporates a high fidelity electronic pressure transducer was positioned into the guiding catheter left in the ascending aorta. Simultaneous measurements were performed with a cuff placed on the patient's left arm. The output signals were recorded in a custom-based acquisition system. The comparison was obtained on the same 10 seconds recorded by the cuff and the pressure wire. The goal will be to reach 85 patients as recommended by the ARTERY Society Task Force. It recommends as an accuracy criterion to achieve a mean difference ≤ 5 mmHg with a standard deviation (SD) ≤ 8 mmHg, which are the standards adopted for this study. Patients with aortic stenosis, atrial fibrillation, or frequent (supra)ventricular extrasystoles were excluded. A total of 197 pairs of measured-estimated cBP were analysed in 78 patients with a mean age of 63 ± 8 yo, 75% of whom were men, 70% had hypertension, 26% fdiabetes, 93% dyslipidemia, 41% were tobacco users and 14% suffered from clinical peripheral artery diseases without history of revascularization. The median (InterQuartiles 25-75%) pBP was 123 [112 134] / 70 [64 77] mmHg. Measured cBP was 102 [92 11] / 78 [70 84] mmHg with a central augmentation index of 34 [23 44] %. The mean difference between estimated and measured systolic cBP was 4.9 ± 6.5 mmHg, while it was -3.9 ± 5.8 mmHg for diastolic cBP, meeting the prespecified accuracy criteria. In conclusion, our approach based on an exact matching and comparison of non-invasive suprasystolic arm cuff measurements and high-fidelity aortic BP validates that an estimation of central aortic blood pressure that can be easily carried out in daily practice and might improve HTN management. It remains to be demonstrated that more cardiovascular complications will be avoided by guiding the antihypertensive therapy with cBP instead of pBP measurements.Bland-Altman of estimated - measured cBP

Solid Contact Microfabricated Electrode for Point-of-Care Electrochemical Determination of a Parasitic Infection Managing Medication Based on a Transducer Layer Prussian Blue Analogue Decorated with Multi-Walled Carbon Nanotubes

Point-of-care diagnostics (POC), often known as on-site testing has evolved as a quick and accurate methodology for analyzing and therapeutic monitoring of drugs. The aim of this study is to provide cost-effective, simple, portable, reliable, and ecofriendly methodology for determination of Tinidazole (TD); potentiometric sensors are found to be an ideal fit for achieving these goals. An advanced microfabricated ion selective electrode is provided employing two-steps procedure. The first is selecting the most selective ionophore for TD determination while the second is to improve the stability and detection limit upon doping the nanoparticles as ion to electron transducer layer between the microfabricated copper electrode and the ion selective media as it can decrease potential drift from 8.0 to ∼1.0 mV h−1. Nernstian potentiometric results were obtained for TD in range of concentration 1.0 × 10−3 to 1.0 × 10−8 M, its slope was −57.43 mV/decade with lower detection limits 2.55 × 10−9 M. Essential values of the adopted sensor are fast and stable response time (9 ± 2 s). The provided potentiometric approach succeeds to asses TD in its pure and pharmaceutical forms, furthermore in different biological fluids with satisfactory results.

Extended Review Concerning the Integration of Electrochemical Biosensors into Modern IoT and Wearable Devices.

Electrochemical biosensors include a recognition component and an electronic transducer, which detect the body fluids with a high degree of accuracy. More importantly, they generate timely readings of the related physiological parameters, and they are suitable for integration into portable, wearable and implantable devices that are significant relative to point-of-care diagnostics scenarios. As an example, the personal glucose meter fundamentally improves the management of diabetes in the comfort of the patients' homes. This review paper analyzes the principles of electrochemical biosensing and the structural features of electrochemical biosensors relative to the implementation of health monitoring and disease diagnostics strategies. The analysis particularly considers the integration of the biosensors into wearable, portable, and implantable systems. The fundamental aim of this paper is to present and critically evaluate the identified significant developments in the scope of electrochemical biosensing for preventive and customized point-of-care diagnostic devices. The paper also approaches the most important engineering challenges that should be addressed in order to improve the sensing accuracy, and enable multiplexing and one-step processes, which mediate the integration of electrochemical biosensing devices into digital healthcare scenarios.

Thermal converter for controlling horizontal wind speed and temperature

This article discusses the design, operation and use of horizontal wind speed and direction control devices. The most commonly used part of the speed converter in the device we analyze is the wind vane converter mounted on the wind vane, which provides an electrical signal of wind direction using a rheostat or electronic transducer. The operating principle of this device is based on the theory of a heat converter, which establishes a relationship between air flow and temperature distribution along the heat conductor of the converter. Purpose : The article is aimed at developing basic concepts and skills about the design, operating principle and methods of using horizontal wind speed and direction control devices. Methods : The operating principle of this device is based on the theory of heat conversion, which establishes the relationship between air flow and temperature distribution along the heat pipe of the converter.

Organic-Inorganic Rare-Earth Double Perovskite Ferroelectric with Large Piezoelectric Response and Ferroelasticity for Flexible Composite Energy Harvesters.

Hybrid organic-inorganic perovskite (HOIP) ferroelectric materials have great potential for developing self-powered electronic transducers owing to their impressive piezoelectric performance, structural tunability and low processing temperatures. Nevertheless, their inherent brittle and low elastic moduli limit their application in electromechanical conversion. Integration of HOIP ferroelectrics and soft polymers is a promising solution. In this work, a hybrid organic-inorganic rare-earth double perovskite ferroelectric, [RM3HQ]2 RbPr(NO3 )6 (RM3 HQ = (R)-N-methyl-3-hydroxylquinuclidinium) is presented, which possesses multiaxial nature, ferroelasticity and satisfactory piezoelectric properties, including piezoelectric charge coefficient (d33 ) of 102.3 pCN-1 and piezoelectric voltage coefficient (g33 ) of 680×10-3 V m N-1 . The piezoelectric generators (PEG) based on composite films of [RM3HQ]2 RbPr(NO3 )6 @polyurethane (PU) can generate an open-circuit voltage (Voc ) of 30V and short-circuit current (Isc ) of 18µA, representing one of the state-of-the-art PEGs to date. This work has promoted the exploration of new HOIP ferroelectrics and their development of applications in electromechanical conversion devices.

Evaluation of Noise Levels in a University Dental Clinic

Noise levels in a dental office can be produced by different specialty instruments. Exposure to high levels of noise (unwanted sounds) may cause auditory and non-auditory health problems in dentists. The aim of this study was to (a) measure the noise levels within different clinics and laboratories of the Department of Dentistry, School of Health Sciences of the National and Kapodistrian University of Athens, (b) promote information sharing on this serious health issue among stakeholders, and (c) collect data to organize preventive measures for students and personnel (faculty members, collaborators, administrative, and technical staff). Since the study did not apply to acoustics and acoustic measurements, a digital sound level meter and noise-integrating dosimeters with an analogue electronic transducer were used to collect data from certain postgraduate (PG) and undergraduate (UG) clinics and laboratories (LAB) during peak working periods and with a duration of 1 h per clinic/lab. Both personal (dosimeters) and static (area monitoring) noise exposure assessments were evaluated, resulting in various teaching-related activities in dental clinics. At all locations, the maximum exposure limit value of 87 dB(A) was not exceeded. However, chairside personal measurements during ultrasonic work revealed that the lower exposure action value of 80 dB(A) was exceeded. PG clinics were noisier than UG. LAB training settings, even with the new equipment, were close to the upper exposure limit due to the simultaneous use of airotors. In this context, targeted research and investigations into measures are proposed to safeguard the health and safety of students during their duties at the dental school.

Solid‐Contact Sensor Based on Molecularly Imprinted Polymers (MIPs) for Direct Potentiometric Assessment of 2,4,6‐Trichlorophenol as a Persistent Organic Pollutant

Abstract2,4,6‐trichlorophenol (TCP) is regarded as a very harmful persistent organic pollutant. It is prohibited by the US EPA due to its stability, possible toxicity, and substantial carcinogenicity, which could result in long‐term harm to both the environment and living things. A novel solid‐contact electrode (SCE) is fabricated and characterized for potentiometric determination of 2,4,6‐trichlorophenol (2,4,6‐TCP). Molecularly imprinted trichlorophenol polymer (MIP) beads are used as a recognition receptor for potentiometric determination of this persistent organic pollutant. The MIPs are synthesized using 4‐vinyl pyridine (4‐VP) and N,N′‐Methylene bis(acrylamide) (N,N‐MBAA) as functional monomer and cross‐linking agent, respectively. They are embedded in a selective polyvinyl chloride (PVC) membrane on the top of multi‐walled carbon nanotubes (MWCNTs), which is used as an ion to electron transducer. The SCE exhibits a Nernstian response with a slope of −55.4±2.1 mV/decade (R2=0.999) over the concentration range of 8.0×10−6 to 1.0×10−4 M, a detection limit of 5.0×10−7 M (0.98 μg/mL), and a response time of <10 s. Using electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP), the suggested SCE′s interfacial capacitance is measured. The interfacial capacitance was increased using MWCNTs and reached 39.7 μF. Also, it prevented the undesirable thin water layer from forming between the conducting glassy carbon (GC) substrate and the sensing membrane. As a result, potential stability is improved, and membrane delamination is avoided. The suggested SCE had a wide range of applications for monitoring TCP in various environmental samples because of the high selectivity, sensitivity, and possible stability that were attained.

Solid-state ion-selective electrodes for the first potentiometric determination of the anti-COVID 19 drug Remdesivir in human plasma; A comparative study

Establishing sensitive and targeted analytical methodologies for drug identification in biological fluids as well as screening of treatments that can counteract the most severe COVID-19 infection-related side effects are of utmost importance. Here, first attempts have been made for determination of the anti-COVID drug Remdesivir (RDS) in human plasma using four potentiometric sensors. Calixarene-8 (CX8) was used as an ionophore applied to the first electrode (Sensor I). The second had a layer of dispersed graphene nanocomposite coating (Sensor II). (Sensor III) was fabricated using nanoparticles of polyaniline (PANI) as ion-to–electron transducer. A reverse-phase polymerization using polyvinylpyrrolidone (PVP) was employed to create a graphene-polyaniline (G/PANI) nanocomposite electrode (Sensor IV). Surface morphology was confirmed by Scanning Electron Microscope (SEM). UV absorption spectra and Fourier Transform Ion Spectrophotometry (FTIR) also supported their structural characterization. The impact of graphene and polyaniline integration on the functionality and durability of the manufactured sensors was examined using the water layer test and signal drift. In the ranges of concentration of 10−7 to 10−2 mol/L and 10−7 to 10−3, sensors II & IV exhibited linear responses; respectively while sensors I & III displayed linearity within 10−6 to 10−2 mol/L. The target drug was easily detectable using LOD down to 100 nmol/L. The developed sensors satisfactorily offered sensitive, stable, selective and accurate estimate of Remdesivir (RDS) in its pharmaceutical formulation as well as spiked human plasma with recoveries ranging from 91.02 to 95.76 % with average standard deviations less than 1.85. The suggested procedure was approved in accordance with ICH recommendations.

Device integration of electrochemical biosensors.

Electrochemical biosensors incorporate a recognition element and an electronic transducer for the highly sensitive detection of analytes in body fluids. Importantly, they can provide rapid readouts and they can be integrated into portable, wearable and implantable devices for point-of-care diagnostics; for example, the personal glucose meter enables at-home assessment of blood glucose levels, greatly improving the management of diabetes. In this Review, we discuss the principles of electrochemical biosensing and the design of electrochemical biosensor devices for health monitoring and disease diagnostics, with a particular focus on device integration into wearable, portable and implantable systems. Finally, we outline the key engineering challenges that need to be addressed to improve sensing accuracy, enable multiplexing and one-step processes, and integrate electrochemical biosensing devices in digital health-care pathways.

EXPERIMENTAL AND NUMERICAL EVALUATION OF AN IN-FLIGHT ANGLE OF ATTACK MEASUREMENT SYSTEM FOR HIGH POWER MODEL ROCKETS

The angle of attack (α) affects the drag, flight path, and flight stability during rocket ascent. This work proposes an in-flight α measurement system based on pressure measurements at the surface of the nosecone for low apogee rockets. An electronic micro differential pressure transducer was selected to measure the pressure difference between selected points in the rocket’s nosecone. Wind tunnel tests were performed to correlate the α with the sensor output at low Mach numbers (Ma ≃ 0.08). The experimental results were further used as a reference for the construction of CFD models of the external flow in the rocket’s nosecone with the aim of predicting the measurements in an extended Mach number range (up to Ma ≃ 0.7). The numerical results allowed for an extended model correlating α with the differential pressure transducer output (Ch). The estimate of model’s errors completes the analysis.

Living Sensors: The Greenest Paradigm in Instrumentation and Measurements

The advent of latest technologies, rising materials and solutions is enabling a brand-new wave of innovation. Going into more detail on electronic solutions, measuring architectures, transducers and sensors, a new environmental issue has emerged concerning the toxicity of such components throughout manufacturing and through use in peculiar applications [1], [2]. It should be noted that these electronic devices typically contain dangerous materials and noxious components, like batteries, which might be venturous for the local communities, and at the same time, have detrimental effects on nature [2]. In this framework, considering the era 4.0 with industry/agriculture 4.0, precision agriculture and smart solutions [3], [4], new ideas and paradigms in the context of sensors have overthrown “classical” devices, such as silicon-based elements, MEMS, semiconductors, and solid state chips. As a matter of fact, the semiconductor manufacturing process and the fabrication of integrated sensors represents an un-green step, far from being considered eco-friendly, considering that the CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emission and pollutants is quite significant during manufacturing [5], [6]. They present, at the same time, limited biodegradability and lack the ability to be absorbed by the environment. In the perspective to conceive more eco-friendly devices, several approaches, mainly based on new compounds, have been addressed in the literature [7].

Introduction on Current Application of Voltage Transformer

As an important equipment, voltage transformer is widely used in power grid to obtain voltage signal and protect the system. In this paper, the voltage transformers in power system are classified according to the working principle. The working principle and characteristics of potential transformer (PT), capacitor voltage transformer (CVT), electronic voltage transformer (EVT) and optical voltage transducer (OVT) are briefly analyzed. Besides, this paper also introduces the principle, category and characteristics of voltage transformer, as well as the application and development of voltage transformer in power system.

Magnetically Tuned Impedance and Capacitance for FeGa/PZT Bilayer Composite under Bending and Longitudinal Vibration Modes

A magnetically tunable magnetoelectric transducer consisting of rectangular Fe82Ga18(FeGa)/Pb(Zr,Ti)O3(PZT) composites is developed, and their magnetoimpedance and magnetocapacitance effects are investigated under bending and longitudinal modes. Specifically, the composites' impedance and capacitance are found to vary with dc magnetic field Hdc, which results from the varied effective dielectric permittivity of the FeGa/PZT composite with Hdc due to the delta E effect, magnetostrictive effect of FeGa and mechanism responsible for ME coupling between the FeGa and PZT layers. Furthermore, the FeGa/PZT bilayered composite exhibits both bending and longitudinal vibration modes due to the asymmetrical stress distributions. The maximum ΔZ/Z of the FeGa/PZT composite is about 215% at the antiresonance frequency fa = 28.78 kHz of the bending-mode, which is 2.53 times as high as that at the antiresonance frequency fa = 107.9 kHz of the longitudinal mode, while the maximum ΔC/C of the FeGa/PZT composite is about 406% at the resonance frequency fr = 28.5 kHz of the bending mode, which is 3.5 times as high as that at the antiresonance frequency fa = 106.6 kHz of the longitudinal mode. This study plays a guiding role for the design and corresponding application of magnetic sensors, magnetic-field-tuned electronic devices and multiple frequency ultrasonic transducers.

A novel screen-printed potentiometric electrode with carbon nanotubes/polyaniline transducer and molecularly imprinted polymer for the determination of nalbuphine in pharmaceuticals and biological fluids

A novel screen-printed electrode (SPE) for potentiometric determination of nalbuphine (NAL) is described. Carboxylated multi-walled carbon nano tubes/polyaniline (f-MWCNTs/PANI) nanocomposite is used as an ion-to- electron transducer and is covered by a selective polyvinyl chloride (PVC) membrane incorporated with molecularly imprinted drug polymer (MIP) beads as a recognition receptor for potentiometric determination a synthetic narcotic, nalbuphine (NAL). The SPE displays a Nernstian response with a slope of 60.3 ± 1.2 mV/decade (R2 = 0.999) over the concentration range 2.4 × 10−7 – 5.0 × 10−2 mol/L and a detection limit of 1.1 × 10−7 mol/L (0.04 μg/mL) with response time less than 20 s (<20 s). The interfacial capacitance of the proposed SPE is measured using chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). The use of the f-MWCNTs/PANI nanocomposite layer improved the interfacial capacitance reached 52.5 μF. Besides, it eliminated the formation of the undesired thin water-layer between the sensing membrane and the conducting substrate. This prevents membrane delamination and increases potential stability. The obtained high selectivity, sensitivity and potential stability offered a great applicability of the proposed SPE for the determination of nalbuphine in hospitals for rapid diagnosis of overdose patients and for quality control/quality assurance in pharmaceutical industry.

An Electrochemical Tilt Sensor with Double-Band Electrodes Fabricated by Wire Winding.

This paper presents the principle, design, fabrication, and characterization of Molecular Electronic Transducer (MET) dual-axis tilt sensors. The proposed sensor has a 3D-printed cylindrical channel inserted with four double-band electrodes and partially filled with a liquid electrolyte. The double-band electrodes were fabricated by wire winding with a ~0.1 mm anode-cathode distance under controlled tension. It allows the electrode to become any 3D coil rather than a 2D structure by microfabrication and exhibits good repeatability (). The tilting changes the electrolyte level and electrode-electrolyte contact area, resulting in Faradaic current changes. The x-axis and the y-axis sensitivity reach 0.121 V/° and 0.154 V/°, respectively.

Selective Ion Sensing in Artificial Sweat Using Low-Cost Reduced Graphene Oxide Liquid-Gated Plastic Transistors.

Health monitoring is experiencing a radical shift from clinic-based to point-of-care and wearable technologies, and a variety of nanomaterials and transducers have been employed for this purpose. 2D materials (2DMs) hold enormous potential for novel electronics, yet they struggle to meet the requirements of wearable technologies. Here, aiming to foster the development of 2DM-based wearable technologies, reduced graphene oxide (rGO)-based liquid-gated transistors (LGTs) for cation sensing in artificial sweat endowed with distinguished performance and great potential for scalable manufacturing is reported. Laser micromachining is employed to produce flexible transistor test patterns employing rGO as the electronic transducer. Analyte selectivity is achieved by functionalizing the transistor channel with ion-selective membranes (ISMs) via a simple casting method. Real-time monitoring of K+ and Na+ in artificial sweat is carried out employing a gate voltage pulsed stimulus to take advantage of the fast responsivity of rGO. The sensors show excellent selectivity toward the target analyte, low working voltages (<0.5V), fast (5-15 s), linear response at a wide range of concentrations (10µm to 100mm), and sensitivities of 1µA/decade. The reported strategy is an important step forward toward the development of wearable sensors based on 2DMs for future health monitoring technologies.

The Role of the Urinary Bladder in the Diagnosis of Abdominal Compartment Syndrome: A Prospective Study in Trauma Patients.

PurposeThe aim of this study was to evaluate the accuracy of bladder pressures in the diagnosis and management of abdominal compartment syndrome (ACS).MethodsAfter Institutional Review Board (IRB) approval, nine operative abdominal trauma patients were prospectively studied over an 18-month period. Bladder pressures were compared to pressures obtained from intra-operatively placed electronic transducer located in the pelvis. Statistical analysis was performed using methods described by Bland and Altman.ResultsA Bland-Altman plot was used to assess the differences between bladder and transducer pressures. There was little agreement between the two methods at low (10-15 mmHg) and high (30-70 mmHg) pressures. At higher pressures, there was a notable difference between these two types of pressure. No patients required repeated operation. One patient died from severe traumatic brain injury.ConclusionMeasurements obtained from the urinary bladder did not agree well with those obtained from within the peritoneal cavity. Furthermore, abdominal pressures greater than 20 mmHg did not show signs of ACS in this selected population, raising doubts about the utility of using abdominal pressures alone in the management of ACS.

Underwater acoustic spiral wave navigation system

A spiral wave navigation beacon is described that creates an outgoing signal with a wavefront that is a diverging spiral cylindrical wave followed by a reference signal of circular wavefront as previously described by Dzikowicz and Hefner in JASA. In this demonstration, the signals are created by driving a cylindrical transducer’s orthogonal sine and cosine modes of vibration in phase quadrature as previously described by Brown and Bachand in JASA. The two dipolar radiation patterns combine to create a helically diverging spiral wavefront that may be used for navigation and communication. The electronic system design and transducer characterization will be presented and are the subject a senior-capstone design project in the College of Engineering at UMass Dartmouth for four of the authors (I.D.B., C.G., K.C., Z.F.). [The project provided a multidisciplinary opportunity in acoustical engineering, instrumentation, calibration, and signal processing and was sponsored by industry (BTech).]

Rapid Demagnetization of New Hybrid Core for Energy Harvesting

This paper presents the results obtained using the rapid demagnetization method in the case of an NdFeB magnet and a new hybrid core. The developed core consists of three basic elements: an NdFeB magnet, Terfenol-D, and a specifically developed metallic alloy prepared by means of a suction casting method. The main goal of proposing a new type of core in the event of rapid demagnetization is to partially replace the permanent magnet with another material to reduce the rare-earth material while keeping the amount of generated electricity at a level that makes it possible to power low-power electrical devices. To “capture” the rapid change of magnetic flux, a small number of coils were made around the core. However, the very low voltage level at very high current required the use of specialized electronic transducers capable of delivering a voltage level appropriate for powering a microprocessor system. To overcome this problem, a circuit designed by the authors that enabled voltage processing from low impedance magnetic circuits was used. The obtained results demonstrated the usefulness of the system at resonant frequencies of up to 1 MHz.

An Electronic Voltage Transducer Based on Electrostatic Charge Escape

An electronic voltage transducer (EVT) based on electrostatic charge escape is proposed in this paper. Its working principle is to apply the electric field (or voltage) to the electrostatic charges of the electrode, and the electrostatic charges are forced to escape directionally to form an escape current, so the voltage measurement can be achieved by detecting the escape current. Based on Gauss’s theorem and dielectric polarization principle, the mathematical models of the new EVT’s power frequency characteristics, harmonic transfer characteristics and transient response characteristics are studied. And the COMSOL multiphysics coupling simulation is employed to verify these characteristics. The simulation shows that the new EVT can linearly transform the primary voltage, realize harmonic measurement, and have satisfactory transient response. Finally, the experiment verification system is established to examine the new EVT. And the result demonstrates that the EVT has a 0.5 class accuracy, and enables to accurately reflect the characteristics of harmonics and impulse voltage.