Pulse Wave Shape Research Articles

Electromagnetic Model of K‐Changes

AbstractK‐changes are observed as step‐like increases in the thundercloud electric fields. The K‐changes occur in the late part of intra‐cloud lightning or during negative cloud‐to‐ground lightning between return strokes. It has been shown that the processes leading to K‐changes initiate in the decayed part of a positive leader channel and propagate toward the flash origin. They are often accompanied by microsecond‐scale electric field pulses. We introduce a new model to simulate processes leading to the K‐changes in cloud‐to‐ground lightning. Our method is based on the full solution of Maxwell's equations coupled to Poisson's equation for the thundercloud charge structure. To model the K‐changes, we gradually increase the decayed channel conductivity. The modeled current wavefront propagates due to the K‐processes downward along a vertical channel and completely attenuates before reaching the ground. We derive the evolution of the linear charge densities and the scalar electric potential along the channel leading to K‐changes. We model electrostatic step‐like changes in the measured electric field together with the approximate rates and amplitudes of the microsecond scale pulses. Step‐like changes increase their amplitudes with the length of the simulated channel and with a higher conductivity of the channel. The microsecond‐scale pulse waveshapes depend mainly on the propagation velocity of the current wave, and the time scale of the conductivity increase. We show that our modeled waveforms are in a good agreement with observations conducted in Florida.

Pulsed Electric Field Technology for Recovery of Proteins from Waste Plant Resources and Deformed Mushrooms: A Review

Proteins are complex molecules, which play a vital role in our body’s function, the building of tissues, and the regulation of metabolic activity. They are crucial to children’s growth and serve as a key component in the body’s process of distributing oxygen. Proteins fuel the body by supplying the required nutrition and energy. Currently, there is an increasing demand for proteins on large scales with no detrimental effects. The adverse health effects of animal proteins have resulted in a growing preference for plant-based proteins, which offer a healthier daily dosage. Valuable proteins can be extracted from various parts of the plant, including stems, leaves, seeds, fruits, vegetables, and roots. Notably, protein extraction from waste plant and mushroom parts minimizes the product wastage and improves the overall production to support economic sustainability. There are several protein extraction techniques available, where the replacement of non-thermal methods with thermal ones is promising nowadays due to the appreciable retainment of protein quality. Pulsed Electric Field (PEF) technology is one of the most efficient non-thermal tools used to assist with extracting these proteins at the minimum processing time and energy consumption when compared with thermal techniques. It relies on the application of a high-voltage pulse between two electrodes to treat samples inside the treatment chamber. While electrode shapes and treatment chamber designs primarily govern the electric field’s application, optimizing process parameters such as electric field strength, pulse width, number of pulses, and pulse waveshape assists in obtaining a desirable enhancement in the protein yield. The primary objective of this review is to explain the PEF-assisted protein extraction process applicable to waste plant parts and deformed mushrooms. While PEF is not a novel concept, utilizing it as a pre-extraction treatment to the aforementioned waste resources would aid in improving the production of value-added protein products economically. So far, PEF has shown immense promise in assisting with protein extraction studies, but requires further research in order to establish this area for large-scale industrial applications.

Multivariate analysis of nanoparticle translocation through a nanopore to improve the accuracy of resistive pulse sensing.

The advent of nanopore-based sensors based on resistive pulse sensing gave rise to a remarkable breakthrough in the detection and characterization of nanoscale species. Some strong correlations have been reported between the resistive pulse characteristics and the particle's geometrical and physical properties. These correlations are commonly used to obtain information about the particles in commercial devices and research setups. The correlations, however, do not consider the simultaneous effect of influential factors such as particle shape and off-axis translocation, which complicates the extraction of accurate information from the resistive pulses. In this paper, we numerically studied the impact of the shape and position of particles on pulse characteristics in order to estimate the errors that arise from neglecting the influence of multiple factors on resistive pulses. We considered the sphere, oblate, and prolate particles to investigate the nanoparticle shape effect. Moreover, the trajectory dependency was examined by considering the translocation of nanoparticles away from the nanopore axis. Meanwhile, the shape effect was studied for different trajectories. We observed that the simultaneous effects of influential parameters could lead to significant errors in estimating particle properties if the coupled effects are neglected. Based on the results, we introduce the "pulse waveshape" as a novel characteristic of the resistive pulse that can be utilized as a decoupling parameter in the analysis of resistive pulses.

Age-Related Changes in Blood Volume Pulse Wave at Fingers and Ears.

The decline in vascular elasticity with aging can be manifested in the shape of pulse wave. The study investigated the pulse wave features that are sensitive to age and the pattern of these features change with increasing age were examined. Five features were proposed and extracted from the photoplethysmography (PPG)-based pulse wave or its first derivative wave. The correlation between these PPG features and ages was studied in 100 healthy subjects with a wide range of ages (20-71 years). Piecewise regression coefficients were calculated to examine the rates of change of the PPG features with age at different age stages. The proposed PPG features obtained from the finger showed a strong and significant correlation with age (with r = 0.76 - 0.77, p < 0.01), indicating higher sensitivity to age changes compared to the PPG features reported in previous studies (with r = 0.66 - 0.75). The correlation remained significant even after correcting for other clinical variables. The rate of change of the PPG feature values was found to be significantly faster in subjects aged ≥40 years compared to those aged < 40 years in the healthy population. This rate of change was similar to the age-related progression of arterial stiffness evaluated by pulse wave velocity (PWV), which is considered a gold standard for evaluating vascular stiffness. The proposed PPG features showed a high correlation with chronological age in healthy subjects and exhibited a similar age-related change trend as PWV. With the convenience of PPG measures, the proposed age-related features have the potential to be used as biomarkers for vascular aging and estimating the risk of cardiovascular disease.

A Study on the Influence of Pulse Wave Shape and Pulse Rate Variation on the Menstrual Cycle and Dysmenorrhea

A Study on the Influence of Pulse Wave Shape and Pulse Rate Variation on the Menstrual Cycle and Dysmenorrhea

Clustered photoplethysmogram pulse wave shapes and their associations with clinical data.

Photopletysmography (PPG) is a non-invasive and well known technology that enables the recording of the digital volume pulse (DVP). Although PPG is largely employed in research, several aspects remain unknown. One of these is represented by the lack of information about how many waveform classes best express the variability in shape. In the literature, it is common to classify DVPs into four classes based on the dicrotic notch position. However, when working with real data, labelling waveforms with one of these four classes is no longer straightforward and may be challenging. The correct identification of the DVP shape could enhance the precision and the reliability of the extracted bio markers. In this work we proposed unsupervised machine learning and deep learning approaches to overcome the data labelling limitations. Concretely we performed a K-medoids based clustering that takes as input 1) DVP handcrafted features, 2) similarity matrix computed with the Derivative Dynamic Time Warping and 3) DVP features extracted from a CNN AutoEncoder. All the cited methods have been tested first by imposing four medoids representative of the Dawber classes, and after by automatically searching four clusters. We then searched the optimal number of clusters for each method using silhouette score, the prediction strength and inertia. To validate the proposed approaches we analyse the dissimilarities in the clinical data related to obtained clusters.

A Basic Study on the Diagnosis Method of Internal Short Circuit based on Feature Extraction and Separation Technique

Lithium-ion batteries are widely used in energy storage systems (ESS) and electric vehicles due to superior performance. However, most safety problems in the use process of the lithium-ion battery are attributed to internal short circuits, there are a lot of factors leading to the internal short circuit. Short circuit in the lithium-ion battery affects the electrochemical reaction and then generating a larger short circuit current. Besides, the thermal runaway is the result of a failure of the separator inside Li-ion batteries, small discharge pulses of a few mV were detected at the time of separator damages. Therefore, the fault diagnosis by internal short circuit of lithium batteries has attracted more attention to prevent the fire accidents. This paper aimed to suggest a diagnostic model for separator of LFP (Lithium iron phosphate) pouch cell as a basic research work using continuous pulse analysis method such as feature extraction and separation technique of pulse source for timely diagnose the short circuit fault. In other words, this paper provided a method that can identify the separator failure before thermal runaway in the aspect of a potential explosion and fire prevention. The internal short circuit signal for diagnosis of LFP pouch cell was investigated by forming artificial defects at the separator part compared with normal battery. To investigate the short circuit signal, artificial defect specimens are prepared as a pouch type, pulse signal was analyzed in terms of pulse waveshape (Skewness) and frequency (Fast Fourier Transform, FFT) compared with normal battery and artificial defect pouch cell. To calculate the continuous acquisition pulse signal, python code was developed. As a result, it is found that the pulse signal of artificial defect specimen shown high frequency and low skewness characteristics. Whereas, in the case of a normal battery, it showed characteristics of relatively low frequency and high or middle skewness. From our research work, the results revealed that the pulse shape and feature contain useful information which can help to understand degradation behavior of the LFP pouch cells. This result is expected to be applicable various batteries with presence a defect at the separator of battery

Model of an automated biotechnical system for analyzing pulseograms as a kind of edge devices

The rapid development of computer biometrics over the past 2-3 decades is largely due to the development and widespread introduction into clinical practice of new methods of studying human body health, including pulse methods. It is possible to judge changes in hemodynamic characteristics, heart rate, and blood flow rate in the studied part of the body based on the parameters of the pulse wave signal. At the same time, the physical processes of the formation of the pulse wave shape have not been fully studied, although the number of biophysical models of blood circulation is quite significant. The development of such a model will allow us to effectively apply modern developments in digital signal processing to the pulse wave and increase its diagnostic value. A qualitative model of pulse signal can be entrusted to the development of the base unit of the biotechnical system as a type of edge device. The work is devoted to the improvement of methods of rapid diagnosis of the cardiovascular system based on the analysis of model pulse-grams. An adequate mathematical model of the pulse wave, which corresponds to real pulse signals in different states of the human body and contains mathematical relationships between the main parameters of pulse-grams, has been refined. The algorithm of express diagnostics with the established criteria of the analysis of pulsograms is offered.

New Methodology of Human Health Express Diagnostics Based on Pulse Wave Measurements and Occlusion Test

Nowadays, with the increase in the rhythm of life, the relevance of using express diagnostics methods for human health state estimation has significantly increased. We present a new express diagnostics method based on non-invasive measurements (the pulse wave shape, heart rate, blood pressure, and oxygen saturation of blood vessels and tissues). A feature of these measurements is that they can be carried out both in the hospital and at home. The new compact and portable optical hardware-software complex has been developed to measure tissue oxygen saturation. This complex makes it possible to reduce the measurement time from 60 min to 7-8 min, which reduces the likelihood of artifacts in the measurement process and increases its reliability. A new technique has been developed to carry out these measurements. A new optical sensor based on a line of charge-coupled devices has been developed to register a pulse wave in the far peripheral zone. The developed new technique for processing the pulse waveform and data on the oxygen saturation of hemoglobin in the blood and tissues allows a person to obtain additional information about their state of health independently. It will help to make conclusions about taking the necessary measures. This additional information allows the attending physician to provide more effective control over the course of treatment of the patient at any time since the methods of express diagnostics proposed by us have no restrictions on the number of applications. The functional state of more than 300 patients was studied. The results of various measurements are presented.

Magnetic and electric antennas synergy for partial discharge measurements in gas-insulated substations: Power flow and reflection suppression

One of the main difficulties in measuring partial discharges (PD) in gas-insulated substations (GIS) is the overlapping of pulses at the sensor’s location, which distorts the pulse resolution and the charge estimation. This research presents a new method called “synergy,” which identifies and suppresses reflections using magnetic and electric antennas in the very-high frequency range. By scaling the antennas’ outputs and adding them, it is possible to segregate forward and backward pulses. Additionally, by multiplying the electric and magnetic signals, the power flow of the pulses is obtained, which identifies the propagation direction and the location of discontinuities in the transmission path. The synergy method is evaluated in three scenarios: a fully matched test bench using a calibrated pulse, a full-scale GIS using a calibrated pulse, and a full-scale GIS using a PD defect. The results showed that the pulse reflections can be eliminated from the incident pulse, improving the charge calculation when the pulses overlap. The output of this research represents an improvement for PD monitoring in GIS, exhibiting a tool for better defect localization, pulse wave shape construction, charge estimation, and possible interference rejection.© 2017 Elsevier Inc. All rights reserved.

AORTIC STIFFNESS ASSESSED BY HIGH-RESOLUTION PHOTOPLETHYSMOGRAPHY AND SINGLE-LEAD ECG

Objective: Aortic stiffness is an independent predictor of cardiovascular risk and plays an important role for the development of cardiovascular disease. However, it is rarely measured in clinical practice as it requires complicated methodology and expensive equipment. We assessed whether high-resolution photoplethysmography (PPG) and single-lead ECG, two methods available in current consumer devices, could be used to measure aortic stiffness. Design and method: Simultaneous recordings of infrared PPG (earlobe and index finger), single lead ECG (PowerLab, ADInstruments) and continuous blood pressure (BP) by the volume-clamp method (Ohmeda 2300, Finapres) at 1000 Hz were made in 33 subjects and repeated after 1–3 wks. Carotid-femoral pulse wave velocity (cfPWV, SphygmoCor, AtCor Medical) and aortic pulse wave velocity (aoPWV, Arteriograph, Tensiomed) were measured as reference. PPG fiducial point identification was refined using pulse wave shapes and the blood pressure signal. Pulse wave analysis extracted 23 features previously associated with arterial stiffness, which were ranked according to univariate strength of correlations with cfPWV and aoPWV. The feature with highest rank was used in a multiple linear regression model with heart rate, body height, mean arterial BP and PAT (ECG R-peak to PPG foot) as covariates. Results: Mean age was 44 (range 21–66) ys, 19 were men, and 5 had hypertension; office BP was 119 ± 12/72 ± 9 mm Hg. PWV was similar at visit 1 and 2 (cfPWV 6.74 ± 1.17 vs 6.80 ± 1.18; aoPWV 7.66 ± 1.80 vs 7.55 ± 1.52). Finger-PPG showed stronger relations with PWV than earlobe-PPG, and 17 of the 23 extracted features showed correlations (P &lt; 0.05) with cfPWV and aoPWV. The ratio of acceleration features (b-c-d-e)/a showed highest correlations with cfPWV and aoPWV (r2 = 0.58 and 0.64, respectively), that improved in multiple regression (r2 = 0.72 and 0.71, respectively; both P &lt; 0.001). Conclusions: High-resolution finger-PPG combined with advanced feature extraction can be used to assess aortic stiffness. Adding body height, BP and single-lead ECG improve the strength of the correlation. Easily available PPG based aortic stiffness may facilitate cardiovascular risk prevention, evaluation, and improve treatment.

Mathematical model of the base unit of the biotechnical system as a type of edge devices

The rapid development of computer biometrics over the past 2-3 decades is largely due to the development and widespread introduction into clinical practice of new methods of studying the human body health, including pulse methods. It is possible to judge changes in hemodynamic characteristics, heart rate and blood flow rate in the studied part of the body based on the parameters of the pulse wave signal. At the same time, the physical processes of formation of the pulse wave shape have not been fully studied, although the number of biophysical models of blood circulation is quite significant. The development of such a model will allow to effectively apply modern developments in digital signal processing to the pulse wave and increase its diagnostic value. Qualitative model of pulse signal can be entrusted to the development of the base unit of the biotechnical system as a type of edge devices. The work is devoted to the improvement of methods of rapid diagnosis of the cardiovascular system based on the analysis of model pulsegrams. An adequate mathematical model of the pulse wave, which corresponds to real pulse signals in different states of the human body and contains mathematical relationships between the main parameters of pulsegrams, has been refined. The algorithm of express diagnostics with the established criteria of the analysis of pulsograms is offered.

Photometric recorder of the carotid artery pulse wave with a system for stabilizing the clamping force

Preventive monitoring, which increases the possibility of diagnosing and curing a disease at an early stage, is interesting and relevant in medical diagnostics. Recently, both minimally invasive and non-invasive diagnostic techniques have become widespread. They include the areas of cardiographic, encephalographic and myographic analyzers designed to study the state of the heart, the brain and striated muscles. The study of the functioning of the smooth muscles of the gastrointestinal tract is carried out using gastro-enterography methods. To obtain an integral assessment of the effectiveness of the circulatory system, the plethysmography method can be successfully applied, which allows modeling vascular tone and blood flow using models of hydrodynamics and the theory of elasticity. The present article analyzes the range of static (or dynamic) informative hemo-parameters that allow diagnosing at the initial stage arterial hypertension, aortic insufficiency or stenosis, atherosclerosis, diabetes mellitus and some other diseases. The photometric reflex absorption in the infrared range, followed by an assessment of blood flow in the aortas and arteries with recording of the shape of pulse waves were used as methods in our research work. The result of the work is a method and a system of computer control of the rod current acting on biological tissues (using the Bluetooth protocol, LabView environment, virtual digital filters and biomedical data archives) that allows non-invasively recording of the parameters of the carotid artery pulse wave.

Plasma blasting of rocks and rocks-like materials: An analytical model

Plasma blasting technology (PBT) is a potential alternative to chemical blasting and mechanical cutting methods for fragmentation of natural rocks, concrete, geopolymers , and other rocks-like materials. We present an analytical model of PBT addressing currently inadequate understanding of the dynamics of shock waves generation and propagation versus the electric energy release conditions. The proposed model describes the operation of the electrical discharge circuit, plasma channel initiation and expansion, and the generation and propagation of shock and pressure waves in the destructible solid. The dynamics of the power generator energy conversion into the plasma channel and into the wave of mechanical stresses in the solid are considered and the main factors determining the efficiency of the method, namely the pulse generator circuit parameters, exploding wire length, and shock wave-transmitting media, are evaluated. Solid fracture efficiency is shown to depend on the pressure pulse wave shape which, in turn, is determined by the rate of electrical energy deposition into the plasma channel. Increasing the exploding wire length leads to an earlier formation of the tensile tangential stresses and to their higher magnitude and thus facilitates material's fragmentation. The use of acoustically stiff media for shock wave transfer marginally improves material's fracture efficiency. Preliminary verification of the functionality of the model was carried out using commercial concretes, with good agreement between the analytically derived and experimentally obtained values. The results demonstrate that the proposed model allows to simulate PBT fracture over a wide range of instrumental and process conditions and can therefore be used for PBT process design, thus realising environmental and economic benefits through significant savings in time and experimental confirmation costs. • Electrical energy deposition rate determines plasma blasting technology efficiency. • Electro-fracture induces up to four zones of change of stresses and deformations. • Superposition of direct and reflected shock waves facilitates rocks fracture. • Increasing exploding-wire length increases shock wave energy and improves fracture. • Acoustically stiff media for shock-wave transfer improves fracture marginally.

Evaluation of Erosion Discharge Characteristics in Inclined Plane Tracking and Erosion Tests on Silicone Rubber under AC and DC Voltages

This paper investigates partial discharge (PD) characteristics that lead to the erosion of silicone rubber (SR) polymer under AC stress and DC stress of both polarities. The experiments are performed on high temperature vulcanized (HTV) SR material samples. The inclined plane test apparatus, constructed in accordance with IEC 60587 requirements, is employed to produce the surface partial discharges and the resulting accelerated aging of the specimens. Two commercial instruments are used to obtain the PD data. A concurrent analysis of visual observations of discharge and PD data is performed to classify discharges based on the severity of material degradation that each type causes. Three types of PD are identified and characterized using diagrams of charge magnitude versus time and a signal processing technique called time-frequency mapping. Individual pulse waveshapes of each type of discharge are also analyzed. PD pulse waveforms are analyzed according to their amplitude, energy, pulse width, and frequency spectrum. These pulse waveform parameters are evaluated and compared for the eroding discharge pulses under AC and DC voltage stresses. It is found that the stages of material degradation during IPT are related to the variations in discharge magnitude and the location of pulse clusters on the time-frequency maps.

Individualized analysis of pulse wave shape before and after a single accurate power exercise in patients with long-term chronic diseases

Objective: To observe and study the resting radial artery pulse wave and changes after a single individualized exercise in patients with long-term chronic diseases. Methods: We selected 16 patients with chronic disease (disease duration ≥5 years) who have been clearly diagnosed as hypertension and/or diabetes and/or hyperlipemia, and first completed the symptom-restricted limit cardiopulmonary exercise testing (CPET). Then a single individualized exercise with Δ50% power as the exercise intensity was completed within one week after CPET. We measured and recorded 50s pulse wave data before exercise and 10 min, 20 min, 30 min after exercise, then obtained each pulse wave characteristic point: starting point (B), main wave peak point (P1), trough of a repulse point (PL), crest of a repulse point (P2), and end point (E). The raw data of the abscissa (time T) and ordinate (amplitude Y) corresponding to each point were derived from the instrument. We treated the end point E of the previous pulse wave as the start point B of the next wave, returned TB to zero, and got the main observation indicators: YB, YP1, YPL, YP2 and TP1, TPL, TP2, TE, and calculated out ΔYP1, ΔYPL, ΔYP2, TE-TPL, (TE-TPL)/TPL, pulse rate, S1, S2 ,ΔYP2-ΔYPL and TP2-TPL as secondary observation indicators. Then calculated the occurrence rate of dicrotic wave with obvious crest. Finally we analyzed individually the 50 s pulse wave data of each patient before and after exercise, and then averaged all the data for overall analysis. Results: ①16 patients with long-term chronic diseases (males 14, females 2), ages (53.7±12.6, 28~80) years old, height (171.7±6.6, 155~183) cm, body weight (80.0±13.5, 54~98) kg. 2YB (91.5±10.8, 71.1~108.6), YP1 (203.6±24.7, 162.7~236.3), YPL (127.1±6.2, 118.2~140.3), YP2 (125.9±6.2, 115.7~137.7), TP1 ( 137.2±22.3, 103.0~197.1), TPL (368.7±29.5, 316.3~434.0), TP2 (422.7±32.8, 376.9~494.7), TE (883.4±95.0, 672.2~1003.3), ΔYP1 (112.1±33.8, 60.3~ 157.5), ΔYPL (35.5±14.2, 17.5~66.2), ΔYP2 (34.4±13.3, 20.0~62.9), TE-TPL (514.6±85.4, 341.4~621.9), (TE-TPL)/TPL (1.4±0.2, 1.0~1.7), pulse rate (68.8±8.4, 59.8~89.3), S1 (0.9±0.3, 0.4~1.4), S2 (0.0±0.0, -0.1~0.0), ΔYP2-ΔYPL (-1.2±2.6,- 6.5 ~ 2.5), TP2-TPL (54.0 ± 10.8, 33.6 ~ 81.1). ③10min after exercise, YB, YPL, YP2, TPL, TE decreased, YP1 increased. ΔYPL, TE-TPL, (TE-TPL)/TPL decreased, and ΔYP1, pulse rate, S1, ΔYP2-ΔYPL, TP2 -TPL increased (all P<0.05). The change trend of pulse wave at 20min and 30min after exercise was consistent with that at 10min after exercise, but most indicators gradually recovered to the resting level before exercise from 10 min. ④The appearance rate of dicrotic wave with obvious crest in 16 patients with long-term chronic disease at rest was 28.6%, and the appearance rate of 10 min (65.7%), 20 min (77.1%), 30 min (73.7%) after exercise was significantly increased (all P< 0.01). In 6 patients, the incidence of dicrotic waves with obvious peaks after exercise was significantly increased, and it could continue until 30 minutes. In 3 patients, the incidence increased significantly 10 minutes after exercise, and began to decrease at 20 minutes. In 1 patient, the rate of appearance only started to increase 20 minutes after exercise. In 2 patients, the incidence increased 10 minutes after exercise and then decreased. In 1 patient, the rate of occurrence increased briefly 20 minutes after exercise and then decreased. The incidence of 1 patient dropped after exercise and began to rise at 20 minutes. In 2 cases, the incidence rate did not increase after exercise, and it increased slightly after 30 minutes. Conclusion: In patients with long-term chronic diseases, the radial artery pulse wave is short and the dicrotic wave is not obvious or even disappears. After a single precise power exercise, the main wave increases, the position of the dicrotic wave decreases, and the amplitude increases. The specific response should be analyzed individually.

Design of Multi Standard Near Field Communication Outphasing Transmitter with Modulation Wave Shaping

The aim of this work is to tackle the problem of modulation wave shaping in the field of near field communication (NFC) radio frequency identification (RFID). For this purpose, a high-efficiency transmitter circuit was developed to comply with the strict requirements of the newest EMVCo and NFC Forum specifications for pulse shapes. The proposed circuit uses an outphasing modulator that is based on a digital-to-time converter (DTC). The DTC based outphasing modulator supports amplitude shift keying (ASK) modulation, operates at four times the 13.56 MHz carrier frequency and is made fully differential in order to remove the parasitic phase modulation components. The accompanying transmitter logic includes lookup tables with programmable modulation pulse wave shapes. The modulator solution uses a 64-cell tapped current controlled fully differential delay locked loop (DLL), which produces a 360° delay at 54.24 MHz, and a glitch-free multiplexor to select the individual taps. The outphased output from the modulator is mixed to create an RF pulse width modulated (PWM) output, which drives the antenna. Additionally, this implementation is fully compatible with D-class amplifiers enabling high efficiency. A test circuit of the proposed differential multi-standard reader’s transmitter was simulated in 40 nm CMOS technology. Stricter pulse shape requirements were easily satisfied, while achieving an output linearity of 0.2 bits and maximum power consumption under 7.5 mW.

Individualization analysis of pulse wave shape characteristics before and after single precise power exercise in young healthy subjects

Objective: To observe and study the resting radial artery pulse wave and the pulse wave changes after a single individualized exercise in young healthy normal subjects. Methods: We selected 16 young healthy graduate students, advanced training doctors, and visiting scholars from Fuwai Hospital without any disease diagnosis and low daily exercise. They first completed the symptom-restricted limit cardiopulmonary exercise testing (CPET). A single individualized exercise with Δ50% power as the exercise intensity was completed within one week after CPET. We measured and recorded 50 s pulse wave data before exercise and 10 min, 20 min, 30min after exercise, let the instrument automatically fix the point and then manually recheck to obtain each pulse wave characteristic point: starting point (B), main wave peak point (P1), trough of a repulse point (PL), crest of a repulse point (P2), and end point (E), and the raw data of the abscissa (time T) and ordinate (amplitude Y) corresponding to each point were derived from the instrument. We treated the end point E of the previous pulse wave as the start point B of the next wave, returned TB to zero, and got the main observation indicators: YB, YP1, YPL, YP2 and TP1, TPL, TP2, TE, and calculated out ΔYP1 (YP1-YB), ΔYPL (YPL-YB), ΔYP2 (YP2-YB), TE-TPL, (TE-TPL)/TPL, pulse rate, S1 (the slope of main wave ascending branch), S2 (the slope of dicrotic ascending branch), ΔYP2-ΔYPL and TP2-TPL as secondary observation indicators; defined the dicrotic wave with obvious crest as YP2>YPL, and calculated the occurrence rate of dicrotic wave with obvious crest (number of waveforms with YP2>YPL in 50 s /total number of waveforms×100%). We analyzed individually the 50 s pulse wave data of each subject before and after exercise, and then averaged all the data for overall analysis. Results: ①16 healthy young subjects (males 10, females 6), age (30.6±6.4, 24~48) years old; height (170.4±8.2, 160~188) cm; body mass (63.9±12.8, 43~87) kg. ②YB (87.2±5.8, 78.1~95.9), YP1 (223.5±15.8, 192.7~242.3), YPL (122.8±7.8, 110.0~133.8), YP2 (131.4±4.9, 116.7~137.5), TP1 (126.2±42.2, 94.2~280.0), TPL (360.2±44.8, 311.5~507.3), TP2 (432.4±50.8, 376.2~589.0), TE (899.7±86.9, 728.3~1042.0). ΔYP1 (136.3±19.9, 96.8~ 158.6), ΔYPL (35.7±10.7, 16.0~55.7), ΔYP2 (44.3±8.1, 22.5~56.5), TE-TPL (539.5±79.3, 405.9~691.3), (TE-TPL)/TPL (1.5±0.3, 0.8~2.0), pulse rate (67.3±6.6, 57.6~82.4), S1 (1.1±0.2, 0.6~1.4), S2 (0.1±0.1, 0.0~0.2), ΔYP2-ΔYPL (8.6±6.1, 0.9 ~19.8), TP2-TPL (72.3±19.9, 38.3~108.4). ③10 min after exercise, YPL (97.0±13.2 vs 122.8±7.8), YP2 (109.6±12.8 vs 131.4±4.9), ΔYPL (6.6±9.8 vs 35.7±10.7), ΔYP2 (19.3±11.2 vs 44.3±8.1), TE (667.8±123.1 vs 899.7±86.9), TE-TPL (330.2±128.4 vs 539.5±79.3), (TE-TPL)/TPL (1.0±0.4 vs 1.5±0.3) decreased, while the pulse rate (92.2± 14.0 vs 67.3±6.6), ΔYP2-ΔYPL (12.7±9.7 vs 8.6±6.1), TP2-TPL (98.0±38.1 vs 72.3±19.9) increased (all P<0.05). The trend of pulse wave changes at 20 min and 30 min after exercise was consistent with that at 10 min after exercise, but from 20 min, most of the indicators gradually recovered to the resting level before exercise. ④The incidence of dicrotic waves with obvious peaks in 16 young healthy persons at rest was 94.5%, and increased at 10 min (96.3%), 20 min (98.5%), and 30 min (99.8%) after exercise (all P<0.01). Among them, the incidence of dicrotic waves with obvious peaks before and after exercise was maintained at about 100% in 10 subjects. The appearance rate of 2 cases had reached 100% before exercise, but it decreased at 10 minutes after exercise, and then continued to increase, at 30 minutes recovered to 100%. Three subjects had a low resting rate and started to increase after exercise. In 1 case, the rate was low only 20 minutes after exercise, considering the influence of human factors. Conclusion: The influence of exercise on the pulse wave of normal people is mainly reflected in the dicrotic wave. On the whole, after a single precise power exercise, the position of the dicrotic wave is reduced, the amplitude is deepened, and the appearance rate of the dicrotic wave with obvious crest is generally increased, and this change can be maintained for at least 30 minutes. From an individual point of view, the response trend of each subject is different.

On the possibility of analysis using the wavelet transform of the pulse waveform from the bloodstream

A method has been developed using wavelet transform to describe the dynamics of the pulse wave shape during the diagnosis of human health. The pulse wave signal, in contrast to the previously discussed diagnostics, is considered an unsteady signal, in which there may be no periodicity. We found that this method is useful for diagnosing the properties of arterial vessels of patients with coronary heart disease, arterial hypertension and other diseases. Pulse wave research results are presented.

Progressive Dynamic Time Warping for Noninvasive Blood Pressure Estimation

Abstract Arterial blood pressure is one of the most important cardiovascular parameters. Yet, current-generation devices for continuous, noninvasive acquisition are few, expensive and bulky. Novel signal processing applied to easily acquired unimodal signals can alleviate this issue, reducing size, cost and expanding the use of such devices to ambulatory, everyday settings. The features of pulse waves acquired by photo- or impedance-plethysmography can be used to estimate the underlying blood pressure. We present a progressive dynamic time warping algorithm, which implicitly parametrizes the morphological changes in these waves. This warping method is universally applicable to most pulse wave shapes, as it is largely independent of fiducial point detection or explicit parametrization. The algorithm performance is validated in a feature selection and regression framework against a continuous, noninvasive Finapres NOVA monitor, regarding systolic, mean and diastolic pressures during a light physical strain test protocol on four clinically healthy subjects (age18- 33, one female). The obtained mean error is 2.13 mmHg, the mean absolute error is 5.4 mmHg and the standard deviation is 5.6 mmHg. These results improve on our previous work on dynamic time warping. Using single-sensor, peripherally acquired pulse waves, progressive dynamic time warping can thus improve the flexibility of noninvasive, continuous blood pressure estimation.