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The global shortage of integrated circuits due to the COVID-19 pandemic has made it challenging to build biopotential acquisition devices like electroencephalography (EEG) hardware. To address this issue, a new hardware system using common ICs has been designed, which is cost-effective, precise, and easily accessible from global distributors. The hardware system comprises 8-channel inputs EEG hardware with a mobile headset capable of acquiring 5-30Hz EEG signals. First two channels of the design is enabled for steady-state visual evoked potential (SSVEP) operations, and the remaining channels can be powered up as needed. A small 3D-printable enclosure is also designed for the hardware board, which is attached to protective glasses to be used as a head-mounted device. The board includes an additional green LED, 4 pulse width modulation (PWM) outputs for general-purpose input/output (GPIO), 2 buttons for input, and exposed programming pins and digital-to-analog converter (DAC) output from the microcontroller unit (MCU). The proposed hardware system is expected to enable students and young researchers to experiment with EEG signals, especially SSVEP, before investing in professional equipment with the availability of programming codes.

Background: Traditional gel-based (wet) electrodes for biopotential recordings have several shortcomings that limit their practicality for real-world measurements. Dry electrodes may improve usability, but they often suffer from reduced signal quality. We sought to evaluate the biopotential recording properties of a novel mixed ionic–electronic conductive (MIEC) material for improved performance. Methods: We fabricated four MIEC electrode form factors and compared their signal recording properties to two control electrodes, which are electrodes commonly used for biopotential recordings (Ag-AgCl and stainless steel). We used an agar synthetic skin to characterize the impedance of each electrode form factor. An electrical phantom setup allowed us to compare the recording quality of simulated biopotentials with ground-truth sources. Results: All MIEC electrode form factors yielded impedances in a similar range to the control electrodes (all <80 kΩ at 100 Hz). Three of the four MIEC samples produced similar signal-to-noise ratios and interfacial charge transfers as the control electrodes. Conclusions: The MIEC electrodes demonstrated similar and, in some cases, better signal recording characteristics than current state-of-the-art electrodes. MIEC electrodes can also be fabricated into a myriad of form factors, underscoring the great potential this novel material has across a wide range of biopotential recording applications. [ABSTRACT FROM AUTHOR]

This paper describes how to produce a wearable dry electrode at a reasonable cost and how to use it for the monitoring of biopotentials in electrocardiography. Smart textiles in wearable technologies have made a great advancement in the health care management and living standards of humans. Graphene was manufactured using the low-cost single-step process, laser ablation of polyimide, a commercial polymer. Graphene dispersions were made using solvent isopropyl alcohol which has low boiling point, nontoxicity, and environmental friendliness. After successive coating of the graphene dispersion on the cotton fabric to make it conductive, the sheet resistance of the resulting fabric dropped to 3% of its initial value. The laser-induced graphene (LIG) cotton dry electrodes thus manufactured are comparable to Ag/AgCl wet electrodes in terms of the skin-to-electrode impedance, measuring between 78.0 and 7.2 kΩ for the frequency between 40 Hz and 1 kHz. The LIG cotton electrode displayed a signal-to-noise ratio of 20.17 dB. Due to its comfort, simplicity, and good performance over a longer period of time, the textile electrode appears suited for medical applications. [ABSTRACT FROM AUTHOR]

Background: The numerous additional valued substances present within plant biowaste products have a wide range of candidates regarding their recycling, promoting the idea of the circular economy. The bell pepper (BP, Capsicum annum L.) has high concentrations of various vitamins and minerals. Also, the biowastes of this plant, including the peels, seeds, and leaves, can represent valuable starting factors for creating medicinal chemicals as an alternative for increasing outcomes and waste in BP production and utilization in the food industrial fields. Aim: This article evaluates the necessary information about the chemical compositions of various colored BP fruits and their associated biomedical characteristics. The BP seeds, fruits, or leaves are rich in bioactive substances such as phenols, flavonoids, carotenoids, α-tocopherol, and pectic polysaccharides. These bioactive molecules may have the ability to be utilized as nutritional substances and display antioxidant, antifungal, antimicrobial, immune-suppressive, and immune-stimulant characteristics. Revalorization of food biowaste products appears in this way as a highly technological and unique field of study with beneficial effects on consumers, finance, and the health of the planet. Conclusion: To make sure that the use of these molecules is effective and to understand their principles of action, more study is required.

This paper presents an amplifier with low noise, high gain, low power consumption, and high linearity for electrocardiogram (ECG) recording. The core of this design is a chopper-stabilized capacitive-feedback operational transconductance amplifier (OTA). The proposed OTA has a two-stage structure, with the first stage using a combination of current reuse and cascode techniques to obtain a large gain at low power and the second stage operating in Class A state for better linearity. The amplifier additionally uses a DC servo loop (DSL) to improve the rejection of DC offsets. The amplifier is implemented in a standard 0.13 μm CMOS process, consuming 1.647 μA current from the supply voltage of 1.5 V and occupying an area of 0.97 mm2. The amplifier has a 0.5 Hz to 6.1 kHz bandwidth and 59.7 dB gain while having no less than a 65 dB common-mode rejection ratio (CMRR). The amplifier's total harmonic distortion (THD) is less than 0.1% at 800 mVpp output. The amplifier can provide a noise level of 1.18 μVrms in the 0.5 Hz to 500 Hz bandwidth that the ECG signal is interested in and has 3.38 μVrms input-referred noise (IRN) over the entire bandwidth, so its noise efficiency factor (NEF) is 2.13. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode's surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation. [ABSTRACT FROM AUTHOR]

Background: Traditional gel-based (wet) electrodes for biopotential recordings have several shortcomings that limit their practicality for real-world measurements. Dry electrodes may improve usability, but they often suffer from reduced signal quality. We sought to evaluate the biopotential recording properties of a novel mixed ionic–electronic conductive (MIEC) material for improved performance. Methods: We fabricated four MIEC electrode form factors and compared their signal recording properties to two control electrodes, which are electrodes commonly used for biopotential recordings (Ag-AgCl and stainless steel). We used an agar synthetic skin to characterize the impedance of each electrode form factor. An electrical phantom setup allowed us to compare the recording quality of simulated biopotentials with ground-truth sources. Results: All MIEC electrode form factors yielded impedances in a similar range to the control electrodes (all Conclusions: The MIEC electrodes demonstrated similar and, in some cases, better signal recording characteristics than current state-of-the-art electrodes. MIEC electrodes can also be fabricated into a myriad of form factors, underscoring the great potential this novel material has across a wide range of biopotential recording applications.

Abstract Flexible and stretchable electronics are a logical choice for the recording of biopotentials, due to their improved patient comfort and customizability. There is, however, significant variance in the signal quality received from these electrodes based on material, size, and target recording frequency. Here we develop a methodology based on Electrochemical Impedance Spectroscopy (EIS) and circuit modeling for optimizing electrodes for a specific application. We use EIS to measure the frequency dependent impedance characteristics of gold (Au) and silver/silver chloride (Ag/AgCl) electrodes of different diameters. Additionally, we use a Randles circuit model and perform model fitting with our data to extrapolate results to arbitrary frequencies and diameters. We found that at low frequencies (

Wearable health trackers for vital signs monitoring are becoming ever more important especially due to the global coronavirus pandemic (COVID-19) caused by the SARS‑CoV‑2 virus which severely affect the respiratory system and can cause cardiac manifestations. Particularly, wearable solutions which can seamlessly monitor heart activity are critical to facilitate personal preventive and remote healthcare, as well as to allow early diagnosis of cardiac dysfunctions. A fundamental enabler of wearable bioelectronics is the sensing bioelectrode which is used to record surface biopotentials. While a plethora of attempts have been reported to realize skin-conformal dry electrodes and electronic skin patches, oftentimes a very critical aspect of the electrode i.e., the actual electrical interfacing of the wearable electrode to readout circuits without disturbing the skin-electrode contact, is overlooked. To address this issue, this paper reports a unique tri-layer, polymer-metal-polymer skin-conformal microelectrode design with sidewall metal coating to achieve vertical interconnect accesses (VIAs) and realize contact pads for external interfacing. The novel and optimized process flow reported herein allows repeatable fabrication of flexible electrodes in arrayed format with yields exceeding 90%. Functionality of the microfabricated electrodes were demonstrated by successful acquisition of the electrocardiogram in lead-I configuration with clear detection of the P-QRS-T complex. [ABSTRACT FROM AUTHOR]

Despite substantial progress in the development of wearable and flexible monitoring systems that conform to the epidermis, most designs focus on either physiological signs such as the electrocardiogram (ECG) results, respiration rate, or metabolites, and ignore the dynamic fluctuations of pH and temperature in sweat during on‐body tests. An advanced butterfly‐inspired hybrid epidermal biosensing (bi‐HEB) patch is presented here, which is interfaced with a custom‐developed miniaturized monitoring system. The patch incorporates a novel transducing layer of nanoporous carbon and MXene (NPC@MXene) for sensitive and durable detection of biomarkers in sweat. The bi‐HEB patch is composed of a glucose biosensor accompanied by pH and temperature sensors to precisely quantify glucose as well as two biopotential electrodes, allowing real‐time recording of electrophysiological (EP) signals. The NPC@MXene‐based glucose biosensor demonstrates an excellent sensitivity of 100.85 µAmm−1 cm−2 within physiological levels (0.003−1.5 mm), and variations in pH and temperature during on‐body perspiration monitoring are calibrated by employing a correction approach. In parallel, the EP electrodes exhibit skin‐electrode contact impedance and biopotential signals similar to those of conventional Ag/AgCl electrodes. Finally, the bi‐HEB patch integrated wearable system is used to accurately monitor sweat glucose and ECG of human subjects participating in indoor physical activities. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode’s surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation.

The current study focuses on fungi that were isolated from cryoconite holes of the Hamtah glacier in the Himalayas. Cryoconite holes have ecological and biotechnological importance. A total of seven cryoconite samples were collected from different locations and subjected to the isolation of psychotropic fungi at 1, 4, 15 and 22 °C. Isolates were identified by ITS and D1/D2 region sequences. The result showed culturable yeasts (45) and filamentous fungi (10) belonging to four ascomycetous classes (Dothideomycetes, Eurotiomycetes, Saccharomycetes and Sordariomycetes) and two basidiomycetes' classes (Microbotryomycetes and Tremellomycetes). Physiological characteristics such as the pH, temperature, salt tolerance, carbon source utilization and antibiotics sensitivity of the isolates were studied. All the isolates were grown from acidic to alkaline pH and were able to grow at 1 to 22 °C. The fungal cultures isolated were screened to produce cold active enzymes such as amylase, cellulase, lipase, protease and catalase. Cellulase activity was detected at its maximum at both 4 and 15 °C. Himalayan cryoconites fungi showed immense potential for biotechnological and industrial applications. To the best of our knowledge, this is the first record of the characterization of fungal communities present in the glacier cryoconites of the Himalayas. [ABSTRACT FROM AUTHOR]

Halophytes are plant species widely distributed in saline habitats, such as beaches, postindustrial wastelands, irrigated lands, salt flats, and others. Excessive salt level, known to limit plant growth, is not harmful to halophytes, which have developed a variety of defense mechanisms allowing them to colonize harsh environments. Plants under stress are known to respond with several morpho-anatomical adaptations, but also to enhance the production of secondary metabolites to better cope with difficult conditions. Owing to these adaptations, halophytes are an interesting group of undemanding plants with a high potential for application in the food and pharmaceutical industries. Therefore, this review aims to present the characteristics of halophytes, describe changes in their gene expression, and discuss their synthesized metabolites of pharmacognostic and pharmacological significance. Lobularia maritima is characterized as a widely spread halophyte that has been shown to exhibit various pharmacological properties in vitro and in vivo. It is concluded that halophytes may become important sources of natural products for the treatment of various ailments and for supplementing the human diet with necessary non-nutrients and minerals. However, extensive studies are needed to deepen the knowledge of their biological potential in vivo, so that they can be introduced to the pharmaceutical and food industries. [ABSTRACT FROM AUTHOR]

Biopotential electrodes have found broad applications in health monitoring, human–machine interactions, and rehabilitation. This article reports the fabrication and applications of ultrasoft breathable dry electrodes that can address several challenges for their long‐term wearable applications—skin compatibility, wearability, and long‐term stability. The proposed electrodes rely on porous and conductive silver nanowire‐based nanocomposites as the robust mechanical and electrical interface. The highly conductive and conformable structure eliminates the necessity of conductive gel while establishing a sufficiently low electrode–skin impedance for high‐fidelity electrophysiological sensing. The introduction of gas‐permeable structures via a simple and scalable method based on sacrificial templates improves breathability and skin compatibility for applications requiring long‐term skin contact. Such conformable and breathable dry electrodes allow for efficient and unobtrusive monitoring of heart, muscle, and brain activities. In addition, based on the muscle activities captured by the electrodes and a musculoskeletal model, electromyogram‐based neural–machine interfaces are realized, illustrating the great potential for prosthesis control, neurorehabilitation, and virtual reality. [ABSTRACT FROM AUTHOR]

The article presents the results of studies on the effect of a bio-correcting food supplement on functional and technological properties of model liver-based pate systems. The supplement included components that are domestic resource-saving sources with predictable biopotential and consumer properties. The food-fortifying supplement was added to the model pate systems in the amount of 10–30%. The aim of the research is to study the effect of bio-correcting supplement on functional and technological properties of liver pate products. Technology of preparing model minced meat systems, along with traditional operations, included the stage of introducing a bio-correcting supplement into the cutter. It has been found that dry supplement components must be hydrated when used in the composition of pate recipes. The process of hydration of the enriching supplement was carried out with drinking water in the ratio of 1:2, and was stirred to a homogeneous state, then kept at the temperature of 19 ± 5°C for 10–15 minutes. That corresponded to the state of saturation of the system biopolymers with moisture and achievement of a pasty consistency, similar to that of pate masses. In the course of the research it was found that the model compositions had higher indicators of functional and technological properties compared with the control ones. The enriching additive in the composition of liver pate increased up to 30% compared with the samples prepared according to the traditional recipe: the moisture-binding capacity by 11–20%, the water-holding capacity by 20–25%, and the emulsifying capacity by 9–14%. The results obtained indicate the possibility of a targeted influence of the additive components on the functional and technological properties of liver pate. When a bio-correcting additive is included in liver pates, the pates get enriched with high-grade protein, vitamins, minerals and essential substances; organoleptic properties of finished products improve; calorie content of products reduces; functional, technological, structural and mechanical properties improve; the risk of broth-fat edema and moisture release from food products reduces; thermal losses decrease and the yield of finished products increases; a new product line of pates with high biopotential and consumer properties is obtained.

Background: The energy flow at acupuncture point is important for understanding the mechanism of acupuncture treatment. However, there are few studies on energy at acupuncture point, and related studies have limitation in explaining the energy flow in all meridians. Thus, we aimed to understand the properties of electrical energy at acupuncture point in twelve meridians by measuring the biopotential at acupuncture and non-acupuncture points. Methods: For each meridian, twenty subjects were participated, and biopotential was measured at five transport points and their adjacent non-acupuncture points. In each subject, both ‘non-stimulation’ and ‘stimulation’ experiments were conducted in random order. The data were analyzed in two parts: biopotential variability and biopotential difference between acupuncture and non-acupuncture points. Results: The biopotential variability at acupuncture point was increased by acupuncture stimulation, and it was related to the activation of Qi flow by acupuncture stimulation. The biopotential difference between acupuncture and non-acupuncture points was formed in the direction related to the Qi flow theory, and this biopotential difference tended to decrease by acupuncture stimulation. Conclusion: The study on biopotential can provide a foundation for research on energy flow mechanism of acupuncture stimulation, and it is expected to overcome limitation of qualitative explanation in traditional medicine.

Flexible and stretchable electronics are a logical choice for the recording of biopotentials, due to their improved patient comfort and customizability. There is, however, significant variance in the signal quality received from these electrodes based on material, size, and target recording frequency. Here we develop a methodology based on Electrochemical Impedance Spectroscopy (EIS) and circuit modeling for optimizing electrodes for a specific application. We use EIS to measure the frequency dependent impedance characteristics of gold (Au) and silver/silver chloride (Ag/AgCl) electrodes of different diameters. Additionally, we use a Randles circuit model and perform model fitting with our data to extrapolate results to arbitrary frequencies and diameters. We found that at low frequencies (<1 Hz), Ag/AgCl had lower overall magnitude impedance than Au and at higher frequencies (1–1000 Hz), Au and Ag/AgCl performed similarly. Further, the magnitude impedance of the electrodes decreased linearly as electrode diameter increased. The methodology described in this study can be applicable to any customizable stretchable electronics fabrication process and enables design optimization for a target frequency, electrode size, and material. [ABSTRACT FROM AUTHOR]

Heavy metals in the water environment are known to have a negative effect on the viability of fish in early development. We have discussed the influence of environmental factors on early embryo development from the viewpoint of the correlation adaptometry method. The analysis of time series with the subsequent construction of a mathematical model was used to determine the change in the greatest effect of certain types of ions on the values of the transmembrane potential for prognostic purposes. The membrane potential is accepted as an integral indicator of the state of the embryos. Structures of five elements of the same type were constructed for the time shifts from 0 to 180 minutes. Each element in the system characterizes the value of the transmembrane potential that was measured in a cell incubated in one of the five solutions during early embryo development. Mathematical models describing the cell membrane potential dynamics have been created and studied. It was noted that the transmembrane potential dynamics of embryo cells is dependent on a change in the value of the correlation coefficient between elements of the system. A decrease in the sum of the correlations between individual elements of the system with an increase in the magnitude of the time shift is established. The results of the numerical solutions of the system equations indicated the sequence of changes in the greatest effect of the incubation medium on the value of the membrane potential in cells. The study of the membrane potentials’ dynamics, using the total values of the strength of correlation, confirmed the influence of heavy metals in the incubation medium on the membrane potential of embryo cell in early development.

This paper presents two designs of a capacitively-coupled chopper instrumentation amplifier (CCIA) successfully implemented in 28 nm CMOS for biopotential sensing applications. The first design is a compact CCIA using offset-blocking for chopping ripple reduction, DC servo loop (DSL) for electrode offset ( $V_{\mathrm {EOS}}$ ) suppression, and a high pass filter (HPF) for handling common-mode (CM) artifacts. An inverter-based self-biased input stage is used for noise and power efficiency. The two gain stages of the CCIA achieve a low-frequency open-loop gain >80 dB. Realized in an area of 0.05 mm2, the CCIA handles $V_{\mathrm {EOS}}$ up to 50 mV and tolerates CM artifacts up to $1.5~V_{\mathrm {pp}}$ . The CCIA achieves a mid-band gain of 39.5 dB with a 1 kHz bandwidth by consuming $1~\mu \text{W}$ . The integrated input-referred noise (IRN) over 200 Hz bandwidth is $2.15~\mu V_{\mathrm {rms}}$ . The second design presents a dual-channel CCIA (DCCIA) using an orthogonal frequency chopping for multi-sensor array applications. An inverter-based input stage is used for noise efficiency. The measured results show that the DCCIA achieves a low-frequency gain of 39.5 dB with a 3-dB bandwidth up to 1 kHz by consuming $0.71~\mu \text{W}$ per channel. The measured noise density is 136 nV/ $\surd $ Hz with an integrated noise of $2.67~\mu V_{\mathrm {rms}}$ over 200 Hz bandwidth. The DCCIA suppresses $V_{\mathrm {EOS}}$ up to 50 mV using the DSL. Realized in a compact area of 0.04 mm2 per channel, an excellent gain matching error of 0.29% is achieved with the crosstalk higher than 58 dB between the channels. This work is a measured report on the instrumentation amplifier using, to the best of the authors’ knowledge, one of the smallest CMOS process nodes.

Krishnan Chakravarthy,1 Hank Bink,2 David Dinsmoor2 1Anesthesiology and Pain Management, University of California San Diego, San Diego, CA, USA; 2Neuromodulation, Medtronic Plc, Minneapolis, MN, USACorrespondence: David DinsmoorMedtronic Plc, 7000 Central Ave NE RCE470, Minneapolis, MN 55432, USATel +1 763 526-8801Email david.a.dinsmoor@medtronic.comPurpose: Spinal cord stimulation (SCS) is a drug-free treatment for chronic neuropathic pain. Recent SCS technology can record evoked compound action potentials (ECAPs) in the spinal cord during therapy and utilize features of the sensed ECAP to optimize the SCS. The purpose of this work is to characterize the relevant parameters that govern the integrity and morphology of acquired ECAPs, and the implications for pain management clinicians and researchers working with ECAPs.Materials and Methods: Eight-contact percutaneous SCS leads were implanted into sheep, and a prototype ECAP-sensing system was used to record spinal cord activity across a range of electrode configurations, pulse widths, and stimulus amplitudes. Similar iterative testing was then completed in human subjects who were undergoing trials of commercial SCS systems.Results: Longer pulse width stimulation results in a progressive increase in ECAP latency, a neurophysiologic effect that enables ECAP sensing with longer pulses despite more encroachment by stimulation artifact. ECAPs may manifest a polyphasic morphology—an effect not seen in all subjects studied—with longer pulse width stimulation; these later phases may be used to assess ECAP amplitude when earlier features are effaced by artifact. Triphasic stimulation limits artifact from spinal cord ECAPs at the expense of potentially higher activation thresholds. If applied, alternating polarity stimulation must account for the ECAP latency differences resulting from alternating sites of neural activation.Conclusion: Together, this information can allow the ECAP to be readily distinguished from the stimulation artifact, although movement may continue to be a confounder; caution is inculcated for ECAP signal processing techniques that rely on the stability of the artifact to avoid clinically misleading results. The promise of closed-loop, ECAP-servoed neuromodulation relies on accurate and proper sensing of the ECAP, while clearly elucidating the clinically relevant trade-offs and design choices made to enable these novel features.Keywords: neuromodulation, closed-loop control, artifact, pulse width, biopotential

Capacitive electrocardiogram (cECG) has been proposed for various applications to extend cardiac monitoring to everyday life. While offering unobtrusive measurement of an electrocardiogram, cECG measurements experience severe motion artifacts with higher amplitudes and longer durations, which results in gaps in the signal availability and deterioration in the signal quality. Time-variant coupling impedance of the cECG results from the variations in the contact pressure of through-clothing cECG measurements and is often used to model the nature of motion artifacts. This article offers a new perspective to utilize the sensitive nature of the coupling impedance by introducing high-frequency sinusoidal variations in the contact pressure. The multiplicative interaction between the source signal and the coupling impedance modulates the amplitude of this sinusoidal with the ECG signal. This new technique is named modulated ECG (mECG), as the ECG signal is merged to the envelope of the resulting carrier wave. The proposed idea of a contact pressure modulated with a high-frequency sinusoidal is investigated analytically in a cECG electrode model. The numerical simulations based on the electrode model are supported by the physical simulations conducted in a test bench using an electrode prototype proposed for mECG measurements. Among the factors influencing mECG measurements, the type of textile, contact pressure, and modulation frequency are investigated. Moreover, the electrode model with a parallel capacitor and resistor as the coupling impedance is evaluated by impedance measurements of textiles. mECG amplitudes are found lower than those of cECG with a factor greater than 398, yet cECG measurements are not affected by the parallel mECG measurements in the tests. Therefore, the mECG technique can supplement the cECG by being measured simultaneously using the same electrode. [ABSTRACT FROM AUTHOR]

This paper presents a second-order voltage-controlled oscillator (VCO)-based front-end for the direct digitization of biopotential signals. This work addresses the non-linearity of VCO-based ADC architectures with a mismatch resilient, multi-phase quantizer, a gated-inverted-ring oscillator (GIRO), achieving >110-dB SFDR. Leveraging the time-domain encoding of the first integrator, the ADC's power is dynamically scaled with the input amplitude enabling up to 35% power savings in the absence of motion artifacts or interference. An auxiliary input-impedance booster increases the ADC's input impedance to 50 MΩ across the entire bandwidth. Fabricated in a 65-nm CMOS process, this ADC achieves 92.3-dB SNDR in a 1 kHz BW while consuming 5.8 µW for a 174.7 dB Schreier FoM. [ABSTRACT FROM AUTHOR]

Wearable biopotential sensing devices are essential to long-term and real-time monitoring of human health. Non-contact, capacitive sensing electrodes prevent potential skin irritations, and are thus beneficial for long-term monitoring. Existing capacitive electrodes are either connected to a separate control circuit via external wires or have limited sensing capacitances, which leads to low signal qualities. This study demonstrates a stretchable capacitive sensing device with integrated electrodes and control electronics, with enhanced signal qualities. The electrodes and the control electronics are fabricated on a common fabric substrate for breathability and strain-limiting protection. The stretchable electrodes are based on an island-bridge design with a stretchability as high as ∼ 100%, and an area ratio as high as ∼ 80%. By using a dielectric calcium copper titanate (CCTO) composite as the adhesive layer, the electrode capacitance can be increased, yielding an enhanced signal-to-noise ratio (SNR) in the acquired biopotentials. This device offers a convenient and comfortable approach for long-term non-contact monitoring of biopotential signals. [ABSTRACT FROM AUTHOR]

Halophytes are plant species widely distributed in saline habitats, such as beaches, postindustrial wastelands, irrigated lands, salt flats, and others. Excessive salt level, known to limit plant growth, is not harmful to halophytes, which have developed a variety of defense mechanisms allowing them to colonize harsh environments. Plants under stress are known to respond with several morpho-anatomical adaptations, but also to enhance the production of secondary metabolites to better cope with difficult conditions. Owing to these adaptations, halophytes are an interesting group of undemanding plants with a high potential for application in the food and pharmaceutical industries. Therefore, this review aims to present the characteristics of halophytes, describe changes in their gene expression, and discuss their synthesized metabolites of pharmacognostic and pharmacological significance. Lobularia maritima is characterized as a widely spread halophyte that has been shown to exhibit various pharmacological properties in vitro and in vivo. It is concluded that halophytes may become important sources of natural products for the treatment of various ailments and for supplementing the human diet with necessary non-nutrients and minerals. However, extensive studies are needed to deepen the knowledge of their biological potential in vivo, so that they can be introduced to the pharmaceutical and food industries.

Endophytes live asymptomatically within the healthy tissues of plant parts of the host, has grabbed the attention of ecologists, chemists, and researchers to have a broad spectral of biotechnological potential. It has been proven that almost all plants harbor endophytes within themselves. Numerous studies indicated that endophytes act as chemical synthesizers of the secondary metabolites of their host plant. Various medicinal plants of the Thar Desert have been used by the local folks of the Rajasthan to treat several diseases ailments for time immemorial. On the basis of their prior knowledge of ethnopharmacological usage of medicinally important plants of Thar Desert, several researchers directed their studies in search of endophytic microflora of such medicinally important plants for the discovery of novel bioactive molecules of pharmaceutical importance, for instance, taxol producing endophytic fungus Phoma sp. isolated from Calotropis gigantea as well as Aspergillus fumigatus, an endophytic fungus reported from Moringa oleifera demonstrated an effective antibiofilm, antimicrobial and antiproliferative activity. This review sheds light on the endophytic microflora of the ethnomedicinal plants of the Thar Desert and their biopotential as a promising source of pharmaceutically important naturally derived compounds.

Sorghum syrup has a saturated carbohydrate composition, which includes cellobiose, maltose, mannose, rhamnose, ribose, fructose, glucose, and sucrose. The present research featured the physicochemical properties of sugar sorghum syrup, i.e. average molecular weight, density, solubility in water, and melting point, and its prospective use in the production of soft ice cream. The carbohydrate composition of sugar sorghum syrup was defined by the method of normal-phase high-performance liquid chromatography. The antioxidant activity of sorghum syrup was determined using the amperometric method. The study of its physicochemical properties proved that it can be used in soft ice cream technology. The sweetness coefficient was determined in comparison with sugar solution and by a taste panel. With an average number of panelists equal to 5, the value of equivalent sweetness was 1.5. This sweetness of sorghum syrup was equivalent to the sweetness of the sucrose solution with minimal concentration. The assessment of the antioxidant activity of sorghum syrup indicated the possibility of its use in functional products with antioxidant properties. The paper introduces a recipe for soft ice cream: cream (20% of fat), milk (3.2% of fat), skimmed milk powder, sorghum syrup, stabilizer ‘Cremodan® SE 334 VEG’, Citri-Fi dietary fiber. The overrun was studied by the method of determining the volume fraction of air; the acidity was determined by the titrimetric method. The resistance to melting was assessed using a cylindrical sample with a diameter of 35 mm and a height of 5 cm. The sample was thermostated at 25 ± 1°C, while the sample area was fixed at regular intervals. The overrun of soft ice cream was 85%, the resistance to melting equaled 20 minutes. Soft ice cream is a popular product among all groups of the population and is widespread in cafes, restaurants, and health-resorts.

This article demonstrates a scalable, time-division multiplexed biopotential recording front-end capable of real-time differential- and common-mode artifact suppression. A delta-encoded recording architecture exploits the power spectral density (PSD) characteristics of Electrocorticography (ECoG) recordings, combining an 8-bit ADC, and an 8-bit DAC to achieve 14 bits of dynamic range. The flexibility of the digital feedback architecture is leveraged to time-division multiplex 64 differential input channels onto a shared mixed-signal front-end, reducing channel area by 2x compared to the state-of-the-art. The feedback DAC used for delta-encoding also serves to cancel differential artifacts with an off-chip adaptive loop. Analysis of this architecture and measured silicon performance of a 65 nm CMOS test-chip implementation, both on the bench and in-vivo, are included with this paper. [ABSTRACT FROM AUTHOR]

Objective: In this paper, we present a novel soft bristle-shaped semi-dry electrode for electroencephalography (EEG) recording. Because the bristle-shaped structure with electric conductivity could overcome the obstacle of hair and enable direct connection to scalp, the semi-dry electrode could work with drinking water instead of saline water that was widely used in previous semi-dry or water electrodes to improve its convenience. The electrode consisted of conductive bristles and a 3D-printed casing. Carbon-coated nylon conductive bristles could achieve low impedance and soft properties of the semi-dry electrode. The bristles could spread on skin and realize a larger contact area. The carbon-coated conductive bristles could also continuously penetrate water into the corneum of skin to reduce contact impedance. The contact impedance of the bristle-shaped semi-dry electrode was similar to the traditional wet electrode, but much lower than dry electrode. Although the saline water had much lower impedance than drinking water, our electrode still achieved even lower skin-electrode contact impedance than previous semi-dry or water electrode with saline water. The alpha rhythms, P300 visual evoked potential, and steady-state visual evoked potential were, respectively, measured to evaluate the electrode performance for EEG recording. [ABSTRACT FROM AUTHOR]

In this paper is presented an experimental electrophysiological device that allows the determination of the optimal light spectrum for the cultivation of plants under artificial conditions. The device contains a light source consisting of red and blue LEDs that are switched on in varying proportions, a biosignal amplifier and a digital data acquisition system. The electric potential collected at the level of the leaves from the stem of the plant in response to exposure to light of a certain spectrum is measured. These potentials generated by the leaves of the plant Crassula ovata illuminated with various associations of red and blue LEDs were compared. It was found that light radiation containing 60% red light and 40% blue light is the most favorable in terms of the efficiency of the photosynthesis process. [ABSTRACT FROM AUTHOR]

The health and fitness of the human body rely heavily on physiological parameters. These parameters can be measured using various tools such as ECG, EMG, EEG, EOG, among others, to obtain real-time physiological data. Analysing the bio-signals obtained from these measurements can provide valuable information that can be used to improve health-care in terms of observation, diagnosis, and treatment. In bio-signal pattern recognition applications, more channels provide multiple information simultaneously. Different biosignal acquisition devices are available in the market, most of which are designed for specific signals like ECG, EMG, EEG etc The gain of the amplifiers and frequency of the filters are designed as per the targeted signals; due to which one device cannot be used for other signals. Also, most of the systems are wired system which is not comfortable for animal studies. In this paper, a low-cost, compact, wireless, 16 channel biopotential data acquisition system with integrated electrical stimulator is designed and implemented. There are several novel and flexible design approaches were incorporated in the proposed design like (1) It has user selectable digital filter in each channel based on the signal frequencies like ECG, EMG, EEG, EOG. The same system will be used to acquire different signals simultaneously. (2) It has variable gain with a configurable analog bandpass filter. (3) It can acquire signals from 4 patients simultaneously. (4) The system is capable to acquire signal from both two-electrode as well as three-electrode configurations. (5) It has integrated stimulator with trapezoidal, charge-balanced, biphasic stimulus output with near zero DC level and user selectable pulse duration or frequency of the stimulus. The developed system has the ability to acquire and transmit data wirelessly in real-time at a high transfer rate. To validate the performance of the system, tests were conducted on the acquired signals using a simulator., (© 2024 IOP Publishing Ltd.)

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This paper discusses various consequences of the fact that the physical nature of process of generation, propagation and measurement of biopotentials is inherently ionic. Source of macroscopic biopotential is the temporary deficit of charge captured by ionic channels, which polarizes the organ border. Electric properties of the living tissue seem to be dominated by the electrolyte which polarizes easily and fast. Current theory of biopotential which treats the body as a volume conductor of certain conductivity is an idealization, which does not consider polarization of tissue. Polarization in quasistatic approximation may be reliably described using the well-known Debye–Hückel theory for electrolytes, derived directly from Boltzmann equation and Poisson equation. The polarization theory for biopotential generation, propagation and measurement is conceptually simple and enables to model wider range of experimental conditions, such as dependence of the potential on ionic strength. Modification of the basic numerical assumption for biopotential modeling: the electroneutrality condition is proposed. The accuracy of the theory is verified by comparison with existing experimental results, which shows very good accuracy. This paper shows the importance of a proper physical description to interpretation of biopotentials. The topic is of special importance to electrophysiology and neuroscience, but affects all biopotential measurements, theories and numerical studies. • Biopotentials come from ion diffusion polarizing the organ border. • Language of excess charge and polarization nicely complements the theory of membrane potential. • Living tissue resembles an electrically isolated conductor, filled with electrolyte. • Debye–Hückel theory for electrolytes well describes propagation of biopotentials. • Polarization theory may help to improve simulation in neuroscience. • Many macroscopic experimental cases may be described using single theory. [ABSTRACT FROM AUTHOR]