Smart Bio-Impedance-Based Sensor for Guiding Standard Needle Insertion

A venipuncture is the most common non-invasive medical procedure, and is frequently used with patients; however, a high probability of post-injection complications accompanies intravenous injection. The most common complication is a hematoma, which is associated with puncture of the uppermost and lowermost walls. To simplify and reduce complications of the venipuncture procedure, and as well as automation of this process, a device that can provide information of the needle tip position into patient’s tissues needs to be developed. This paper presents a peripheral vascular puncture control system based on electrical impedance measurements. A special electrode system was designed to achieve the maximum sensitivity for puncture identification using a traditional needle, which is usually used in clinical practice. An experimental study on subjects showed that the electrical impedance signal changed significantly once the standard needle entered the blood vessel. On basis of theoretical and experimental studies, a decision rule of puncture identification based on the analysis of amplitude-time parameters of experimental signals was proposed. The proposed method was tested on 15 test and 9 control samples, with the results showing that 97% accuracy was obtained.

Patient Specific Numerical Modeling for Renal Blood Monitoring Using Electrical Bio-Impedance

Knowledge of renal blood circulation is considered as an important physiological value, particularly for fast detection of acute allograft rejection as well as the management of critically ill patients with acute renal failure. The electrical impedance signal obtained from kidney with an appropriate electrode system and optimal electrode system position regarding to the kidney projection on skin surface reflects the nature of renal blood circulation and tone of renal blood vessels. This paper proposes a specific numerical modelling based on prior information from MRI-data. The numerical modelling was conducted for electrical impedance change estimation due to renal blood distribution. The proposed model takes into the account the geometrical and electrophysiological parameters of tissues around the kidney as well as the actual blood distribution within the kidney. The numerical modelling had shown that it is possible to register the electrical impedance signal caused by renal blood circulation with an electrode system commensurate with the size of kidney, which makes it possible to reduce the influence of surrounding tissues and organs. Experimental studies were obtained to prove the numerical modelling and the effectiveness of developed electrode systems based on the obtained simulation results. The obtained electrical impedance signal with the appropriate electrode system shows very good agreement with the renal blood change estimated using Doppler ultrasound. For the measured electrical impedance signal, it is possible to obtain the amplitude-time parameters, which reflect the hemodynamic characteristics of the kidneys and used in diagnostics, which is the subject of further research.

Performance Improvement of Supercapacitor Materials with Crushed 3D Structured Graphene

Conventional 2D-graphene sheets (2D-rGO) often demonstrate poor performance as capacitor materials, especially in cyclability due to the lamellar stacking and agglomeration of the electrode materials. Herein, we have proposed that crushed 3D-graphene (c-3D-rGO) can overcome the limitation. A simplistic way to prepare 3D-crushed graphene structures has been presented utilizing metal rGO core-shell (Ni@rGO) followed by acid leaching. The electrochemical performances of the prepared c-3D-rGO were evaluated as capacitor material using a three-electrode system with aqueous 0.5 M Na2SO4 solution through cyclic voltammetry and galvanostatic charge-discharge measurements. 2D-rGO was separately prepared to compare the performance with 3D-crushed graphene structures. It has been observed that the calculated specific capacitance (Csp) value of the prepared c-3D-rGO was 335 Fg-1 at a current density of 0.15 Ag-1, which was about three times higher than that of the 2D-rGO. The c-3D-rGO electrode retained 100% capacitance of its initial value after 10000 cycles, demonstrating the material’s excellent electrochemical stability. Furthermore, to show the performance in hybrid capacitor, manganese oxide (MnOx) with c-3D-rGO. The presence of c-3D-rGO significantly improved the capacitive performance MnOx.

Solar-Driven Simultaneous Electrochemical CO2 Reduction and Water Oxidation Using Perovskite Solar Cells

The utilization of solar energy into electrochemical reduction systems has received considerable attention. Most of these attempts have been conducted in a single electrolyte without a membrane. Here, we report the system combined by the electrochemical CO2 reduction on the Au dendrite electrode and the water oxidation on the Co-Pi electrode with a Nafion membrane. An efficient reduction of CO2 to CO in the cathode using the proton from water oxidation in the anode is conducted using perovskite solar cells under 1 sun condition. The sustainable reaction condition is secured by balancing each reaction rate based on products analysis. Through this system, we collect reduction products such as CO and H2 and oxidation product, O2, separately. Employing separation of each electrode system and series-connected perovskite solar cells, we achieve 8% of solar to fuel efficiency with 85% of CO selectivity under 1 sun illumination.

Hierarchical NiMn Double Layered/Graphene with Excellent Energy Density for Highly Capacitive Supercapacitors

In the present article, highly capacitive NiMn-LDHs/GO composite of electrode material has been the synthesized for supercapacitor energy storage. Various analytical techniques (particularly X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), and scanning electron microscope (SEM)) have been employed to characterize the as-synthesized NiMn-LDHs/GO. The Microscopic images obtained using HRTEM analysis clearly reveal the formation of lattice fringe pattern (lattice spacing as ~ 0.22 nm) for GO, whereas SEM images shows highly porous nature. The super-capacitive performance of the as-synthesized electrode material have been accessed through an electrochemical work station comprising of a 3-electrode system. The working electrode made up of NiMn-LDHs/GO (Active material) on Ni foil (working electrode) with the help of PVDF (binder), has shown specific capacitance of 1964 F g−1 at current density of 1 A g−1 with Galvanostatic charging/discharging (GCD) technique. It has also shown remarkable cyclic stability with a capacitance retention of 98% after 2000 cycles. The high-power density (401 W/kg) and energy density (17.78 Wh/kg) signify the high-level electrochemical supercapacitor behaviour in charge storage applications.

Hydrothermal Synthesis of CuO/RuO2/MWCNT Nanocomposites with Morphological Variants for High Efficient Supercapacitors

In this study, we develop the optimum composition of copper oxide/ruthenium oxide and multi-walled carbon nanotubes (CuO/RuO2/MWCNTs) ternary nanocomposite via a hydrothermal method as an efficient electrode material for supercapacitor applications. The ratio between CuO and RuO2 varied to improve the electrochemical performance of the electrode. The synthesized nanocomposites are analyzed by high-resolution scanning electron microscopy (HR-SEM), thermo gravimetric analyzer (TGA) and electrochemical impedance spectroscopy (EIS). Furthermore, the elemental composition is analyzed by energy dispersive X-ray (EDX) spectroscopy and the specific capacitance was analyzed by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) methods. The electrochemical investigations is conducted in a three-electrode system and the sample is attached on a stainless steel plate as the working electrode; platinum wire works as the counter electrode and Ag/AgCl electrode as the reference electrode, adopting 3 M (NH4)2SO4 as the electrolyte. The resultant of CuO/RuO2/MWCNT nanocomposite with 7 wt% Cu and 20 wt% Ru was found to perform the highest specific capacitance of 461.59 F/g in a current density of 1 A/g.

Bio-Impedance Sensor for Real-Time Artery Diameter Waveform Assessment

The real-time artery diameter waveform assessment during cardio cycle can allow the measurement of beat-to-beat pressure change and the long-term blood pressure monitoring. The aim of this study is to develop a self-calibrated bio-impedance-based sensor, which can provide regular measurement of the blood-pressure-dependence time variable parameters such as the artery diameter waveform and the elasticity. This paper proposes an algorithm based on analytical models which need prior geometrical and physiological patient parameters for more appropriate electrode system selection and hence location to provide accurate blood pressure measurement. As a result of this study, the red cell orientation effect contribution was estimated and removed from the bio-impedance signal obtained from the artery to keep monitoring the diameter waveform correspondence to the change of blood pressure.