AgCl Electrode Research Articles

Design and Evaluation of Korean Electropalatography (K-EPG).

Recently, the development of medical rehabilitation technology has resulted in an increased interest in speech therapy equipment. In particular, research on articulation therapy for communication disorders is being actively conducted. The existing methods for the diagnosis and treatment of speech disorders, such as traditional tactile perception tests and methods based on the empirical judgment of speech therapists, have many limitations. Moreover, the position and contact force of the tongue are key factors in speech disorders with regards to articulation. This is a very important factor in the distinction of Korean characters such as lax, tense and aspirated consonants. In this study, we proposed a Korean-electropalatography (EPG) system to easily measure and monitor the position and contact force of the tongue during articulation treatment and diagnosis. In our proposed K-EPG system, a sensor was fabricated using an AgCl electrode and biocompatible silicon. Furthermore, the measured signal was analyzed by implementing a bio-signal processing module and monitoring program. In particular, the bio-signal was measured by inserting the device into the palate of an experimental healthy test group (four subjects). Through these experiments, we confirmed that our K-EPG system could be applied to clinical treatment in speech therapy.

Relationship between microstructure of AgCl film and electrochemical behavior of Ag|AgCl electrode for chloride detection

The electrochemical behavior of Ag|AgCl electrode for chloride detection is closely related to the microstructure of AgCl film on the electrode surface. In this study, the surface properties and electrochemical behavior of Ag|AgCl electrode prepared with different current density were investigated. With a higher current density, the distance for ions diffusion through the boundaries of AgCl grains was reduced, due to the tended growth of AgCl at crystal plane (111) and formation of more spherical AgCl grains and porous AgCl film. As a result, both the electrical resistivity of AgCl film and Rct of Ag|AgCl electrode decreased.

Multi-component Zn2SnO4/MoS2/Ag/AgCl for enhancing solar-driven photoelectrocatalytic activity

In this study, efficient photoelectrocatalyst Zn2SnO4/MoS2/Ag/AgCl (ZTO/MoS2/Ag/AgCl) was prepared by hydrothermal method followed with the in-situ deposition process. ZTO/MoS2/Ag/AgCl electrode exhibited significant photoelectrocatalytic activity by degrading Methylene Blue (MB) and phenol of 96.5% and 68% respectively under simulated solar light within 2 h. According to a series of analysis and characterization, the results indicated that the multi-component ZTO/MoS2/Ag/AgCl not only broadened the visible light response ranges, but also restrained the recombination of charge carriers remarkably, which was due to the synergistic of SPR effect of Ag particles, and the agglomeration status in the special flake structures of MoS2. In addition, MoS2 also functioned as an electron mediator. Based on our results, we proposed a rational schematic mechanism for improved photoelectrocatalytic performance. This research provided exceptional insights for the use of zinc stannate-based materials for environmental remediation.

Salinity Gradient Energy Conversion Using Permselective Organic Liquid Membranes

The increases of worldwide energy consumption and the concern about the environment have made us pay attention to eco-friendly and renewable energy, such as solar power, wind power, water power, geothermal power, biofuel energy, etc. [P. A. Owusu and S. Asumadu-Sarkodie, Cogent Eng., 3, 1167990 (2016)]. The salinity gradient between seawater and river water must be one of such energy sources. Reverse electrodialysis (RED) is a power generation system which translates salinity gradient energy to electricity by the use of ion-exchange membranes [Y. Mei and C. Y. Tang, Desalination, 425, 156 (2018)]. Since the waters are sufficient on Earth and RED using them does not generate harmful waste, RED can supply electricity in a sustainable and eco-friendly manner. However, the drop in the power capacity owing to the large resistance of the river water, the high cost of ion-exchange membranes, deterioration and clogging of ion-exchange membranes, etc. are serious problems to be solved.We used organic liquid membranes instead of ion-exchange membranes as the permselective membranes for a RED system. Liquid membranes are often employed in the field of ion sensors in order to give electrodes the selectivity on the objective ions. The permselectivity of the liquid membranes is attributed to both the difference in the transfer energies of coexisting ions and the concentration ratio of them. The characteristics of the liquid-membrane type electric cell were studied.A Na+-permselective liquid membrane (Na+-LM) was prepared in the following manner. First, a 0.2-mm-thick polytetrafluoroethylene (PTFE) sheet opening a hole of 1.0 cm diameter was put on a flat glass plate and was fixed with clips. 74 mg of Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), 100 mg of polyvinyl chloride (PVC), and 0.8 mL (L = dm3) of 2-nitrophenyl octyl ether (NPOE) were dissolved in 4 mL of tetrahydrofuran (THF). Then, 0.1 mL of the THF solution was poured into the hole, and the solvent was dried for a day. Finally, a Na+-LM was formed within the hole on the glass plate. The membrane was peeled off from the glass plate and was used along with the PTFE sheet. Similarly, a Cl−-permselective liquid membrane (Cl−-LM) was prepared by the use of a THF solution containing 42 mg of tetraoctylammonium chloride (TOcACl), 100 mg of PVC, and 0.8 mL of NPOE in 4 mL of THF. The thickness of the membranes (Na+-LM and Cl−-LM) was 13 μm.The cell is mainly composed of three aqueous phases (W1, W2, and W3), two permselective liquid membranes (Na+-LM and Cl−-LM), and two Ag|AgCl electrodes (RE1 and RE2). The composition of the cell is as follows: RE1|W1|Na+-LM|W2|Cl−-LM|W3|RE2. W1 and W3 contained 1.0 mol L−1 NaCl aqueous solutions, which corresponded to seawater. A 50 mmol L−1 NaCl aqueous solution simulating river water was used as W2. The thickness of W1 and W3 and that of W2 are 2.3 cm and 2.8 cm, respectively.The power density of the cell was evaluated by normal pulse voltammetry. The potential of the cell, E, was taken as the potential of RE2 against RE1. In each step, E was maintained at the electromotive force E emf (or the open circuit potential) for 370 s, and then the rectangular pulse voltage was applied for 50 s. The current due to the Na+ flow from W1 to W3 was taken to be positive. The measurement was conducted at 298 ± 1 K.The result is shown in the attached figure. The time-course of the current density j and that of E were expressed as a solid line and a broken line, respectively. The measured value of E emf was 138 mV under the conditions. The calculated value of E emf by the Nernst equation using the activities of Na+ and Cl− is 140 mV, and the agreement between the two E emf values demonstrates that Na+-LM and Cl−-LM played as ideal permselective membranes. In order to evaluate the power density of the cell, the values of j at the last 2 s of each pulse were averaged and were related to the E values. The maximum power density was 14 μW cm−2 at 69 mV.In the present study, the liquid membranes were used instead of ion-exchange membranes for the RED system. The NPOE solution of NaTFPB and that of TOcACl showed the good permselectivity in the NaCl aqueous solution. The liquid membranes are able to replace the ion-exchange membranes used in RED systems. Figure 1

Analog Realization of Fractional-Order Skin-Electrode Model for Tetrapolar Bio-Impedance Measurements

This work compares two design methodologies, emulating both AgCl electrode and skin tissue Cole models for testing and verification of electrical bio-impedance circuits and systems. The models are based on fractional-order elements, are implemented with active components, and capture bio-impedance behaviors up to 10 kHz. Contrary to passive-elements realizations, both architectures using analog filters coupled with adjustable transconductors offer tunability of the fractional capacitors’ parameters. The main objective is to build a tunable active integrated circuitry block that is able to approximate the models’ behavior and can be utilized as a Subject Under Test (SUT) and electrode equivalent in bio-impedance measurement applications. A tetrapolar impedance setup, typical in bio-impedance measurements, is used to demonstrate the performance and accuracy of the presented architectures via Spectre Monte-Carlo simulation. Circuit and post-layout simulations are carried out in 90-nm CMOS process, using the Cadence IC suite.

Self‐Potential Tomography of a Deep‐Sea Polymetallic Sulfide Deposit on Southwest Indian Ridge

AbstractDeep‐sea polymetallic sulfides associated with hydrothermal systems are considered a potential viable resource for base and precious metals. The Southwest Indian Ridge (SWIR, Indian Ocean) hosts active and inactive hydrothermal systems. Inactive hydrothermal fields are more abundant than active fields but are difficult to remotely characterize. We report a deep‐sea self‐potential investigation to locate inactive ore deposits at the Yuhuang hydrothermal field on the ultraslow‐spreading SWIR. A horizontal array of six nonpolarizing AgCl electrodes are attached to a deep‐towed transient electromagnetic system to record the electrical field at a height of 40 m above the seafloor. The observed electrical field strength near a previously recognized sulfide deposits (verified by drilling) reaches an amplitude of 0.5 mV/m. Negative self‐potential anomalies (~ −27 mV) were observed by integrating the measured electrical field. The high electrical conductivities (up to 12 S/m) of sulfide samples measured in the laboratory and the oxidized sulfides recovered from the surface of the deposit suggest that the self‐potential anomalies are due to sulfide mineralization and corrosion of the polymetallic sulfides. Inversion of the self‐potential data reveals a localized body with a thickness of ~65 m, which is interpreted as the Yuhuang ore deposit. Our field data demonstrate that the self‐potential method is a useful exploration method to identify and image seafloor massive sulfide deposits hosted in inactive hydrothermal fields at mid‐ocean ridges.

A Simple Synthesis Method of Single-Size AgCl Nano-Particles and Its Discharge Behavior

Single-size AgCl nanoparticles were successfully synthesized through a direct precipitation method with ethylene diamine tetraacetic acid (EDTA) as the complexant. Fourier transform infra-Red (FTIR), X-ray diffraction (XRD), scanning electron micro spectroscopy (SEM) and density functional theory (DFT) calculation were conducted to analyze the structure and morphology. Linear sweep voltammetry and cyclic voltammetry (CV) were used to evaluate the electrochemical activity. The kind of formed complexes between Ag+ and EDTA in the solutions changes by varying pH values in the solution. The stability of the formed complexes differs from each other, which notably affects the nucleation and growth of AgCl particles in the solutions and subsequently the particle size and morphology of synthesized AgCl particles. The reactants concentration, temperature and CAg+/CEDTA ratio are also dominant to the particle size and morphology of synthesized AgCl particles. Single-size AgCl nanoparticles (75 nm) with spherical shape were synthesized. The AgCl electrodes prepared by synthesized AgCl nanoparticles show the highest current density of 15.2 mA/cm2 at potential −0.2 V and excellent cathodic and anodic recycling properties, indicating that the AgCl electrode is suitable for use as the electrode for rechargeable seawater battery.

Effect of Zn2+ on Cathodic Reaction of Carbon Steel in Aqueous MgCl2 Solutions

We have shown that zinc dissolution is accelerated in relatively high concentrations of MgCl2 during the galvanic corrosion process consisting of zinc and carbon steel. In this study, in order to understand further the galvanic corrosion process of zinc and carbon steel in MgCl2, the cathode reaction on carbon steel was investigated in MgCl2 aqueous solution with and without Zn2+ which is generated during the galvanic corrosion process.The sample used for the experiment was carbon steel SS400 (Fe-0.12C-0.60Mn-0.011P-0.019S) machined to a shape of 1.5 × 1.5 × 0.3 cm3. One side of this sample was ground up to #2000 grit with SiC abrasive papers and then degreased and washed in acetone before use in the following experiments. The test solutions were mixtures of 0.25 M MgCl2 and x mM ZnCl2 (x = 2.5, 5 mM, Mg / Zn molar ratio: 100, 50) and they were used at room temperature under a naturally aerated condition. As reference solutions, the mixtures of 0.5 M NaCl and y mM ZnCl2 (x = 5, 10 mM, Na / Zn molar ratio: 100, 50) with the same Cl- concentration were used. The cathodic polarization curve measurements were done by a conventional three-electrode method with a platinum wire as a counter electrode and an Ag / AgCl electrode (saturated KCl, SSE) as a reference electrode. The potential sweep rate was 0.5 mV/sOn the cathodic polarization curves for carbon steel measured in an aqueous MgCl2 solution containing Zn2+, the diffusion-limiting current region due to the cathodic reduction reaction of dissolved oxygen (ORR) was observed from -0.6 V to -0.8 V, and the magnitude of the limiting currents were almost the same regardless of the Zn2+ concentration. Furthermore, the cathodic polarization curves showed that an increase in the current due to the hydrogen evolution reaction (HER) occurred in the MgCl2 solution without Zn2+. By comparison with the cathodic polarization curve measured in the NaCl solution without Zn2+ showed a diffusion-limiting current of ORR was comparable to that in the MgCl2 solution, but the overvoltage of HER was increased by about 0.1 V. These results indicated that in the MgCl2 solution, HER on carbon steel was enhanced more than that in NaCl aqueous solution.On the other hand, in the MgCl2 solutions containing Zn2+, a shoulder was observed in the cathode polarization curve at around -0.95 V, and the the current due to HER was decreased with increasing the Zn2+ concentration. It was shown that HER was suppressed in MgCl2 solutions by the presence of Zn2+. This may be attributed to the precipitation of zinc corrosion products formed during cathodic polarization.

Polyelectrolyte‐Coated Copper Hexacyanoferrate and Bismuth Oxychloride Electrodes for Efficient Salinity Gradient Energy Recovery in Capacitive Mixing

A mixing entropy battery (MEB) based on a pair of cationic and anionic electrodes is a novel method to extract salinity gradient (SG) energy. However, so far, only precious AgCl electrodes are reported as anionic electrodes in MEBs. Herein, it is demonstrated that bismuth oxychloride (BiOCl) can be an alternative anionic electrode for MEBs to harvest SG energy. In tests with 30 and 1 g L−1 NaCl solutions, the origin MEB with uncoated BiOCl anionic and copper hexacyanoferrate (CuHCF) cationic electrodes produces an energy density of 8 J m−2 and an average power density of 59 mW m−2. To boost the power output, the origin BiOCl and CuHCF electrodes are coated with polyelectrolytes. The energy density (12 J m−2) and average power density (87 mW m−2) of the coated MEB are nearly 50% higher than those of the origin MEB and are stable over 50 cycles, which is comparable and even higher than those with AgCl anionic electrodes. These results indicate that BiOCl can be a cheap alternative to the AgCl anionic electrode, and polyelectrolyte coatings can be a cheaper alternative to ion‐exchange membranes in MEBs for efficient SG energy recovery.

Optimization of Pyrrole Electropolymerization on a Steel Gauze Electrode Using the Cyclic Voltammetry Method

Study on pyrrole electropolymerization is the preliminary step in synthesizing polypyrrole membranes, which can be used for various purposes in biosensor. In this work, electropolymerization process and electrochemical analysis of polypyrrole as an electroactive polymer have been studied by cyclic voltammetry. Pyrrole was electropolymerized to form polypyrrole in an aqueous potassium chloride solution at different pHs using phosphate buffer. The results showed that a potential range of 0-1200 mV is suitable for polypyrrole electropolymerization using the Ag|AgCl electrode as the reference. The formation of polypyrrole is stable at a scan rate of 100 mV/s. In addition, the optimized pyrrole electropolymerization was obtained using 0.1 M pyrrole and phosphate buffer at pH of 2-6. Taken together, this study can be used as a reference for the synthesis of other conducting polymers.

Design of a Bimetallic Electrode (Ag-Cu) for Electrochemical Reduction of Carbon Dioxide (CO2) to Value-Added Chemical Products.

KEYWORDS: Bimetallic electrode (Ag-Cu), electrochemical reduction of carbon dioxide, electrocatalyst, electrodeposition, faradaic efficiency.Carbon dioxide (CO2) is the last of the by-products in all processes that involve the complete oxidation or combustion of any carbonaceous organic matter. Considering this and the high amount of fossil energy sources, CO2 is currently considered as environmentally harmful. Given this scenario, it is essential to re-value carbon dioxide, since it represents a potential raw material or carbon source for obtaining value-added chemical products. In this context, the electrochemical reduction of CO2 represents an attractive alternative since it has proven to pose various advantages over other current technologies to conduct the molecular conversion of this compound.The efficiency of the electrochemical reduction of CO2 depends to a large extent on the activity and selectivity of the cathode electrocatalyst, so that the appropriate electrocatalysts are necessary to promote the chemical reactions of electrosynthesis. Therefore, a key point for the electrochemical reduction of CO2 is the selection of such an electrocatalyst.In this work, a bimetallic silver-copper catalyst (Ag-Cu) with different Cu concentration was prepared and its faradaic efficiency was established in the electrochemical reduction of CO2 towards added value chemical compounds like methanol, acetic and formic acids. The modification was made on a Ag sheet (1 mm thick, 2 cm2 surface area and 99.9% purity), the deposition electrolyte was prepared from a 1.0 M solution of copper sulphate pentahydrate (CuSO4 • 5H2O 99.8 %). The surface modification of the bimetallic electrode was performed by electrolysis at controlled potential (-520 mV vs the Ag / AgCl electrode) at three different programmed times: 5, 10 and 15 min. The so prepared electrodes were characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) and tested in the electrochemical reduction of CO2 in aqueous medium. The by-products were determined by HPLC-IR. The faradaic efficiencies was determined for the reaction products. REFERENCES - ElMekawy, A., Hebag, M. H., Mohanakrishna, G., Elbaz, A. F., y Bulut, M., 2016. Technological advances in CO2 conversion electro-biorefinery: A step toward commercialization. Bioresource Technology, pp. 752-766.- Ganesh, I., 2016. Electrochemical conversión of carbon dioxide into renewable fuel chemicals – The role of nanomaterials and the comercialization. Renewable and Sustainable Energy Reviews, 59, pp. 1269-1297.- Kumar, B., Brian, J. P., Atla, V., Kumari, S., Bertram, K. A., White, R. T., y Spurgeon, J. M., 2016. New trends in the devolopment of heterogeneous catalysts for electrochemical CO2 reduction, Catalysis Today, 270, pp.19-30.- Merino, G. I., 2016. Electrochemical membrane reactors for the utilisation of carbon dioxide. Chemical Engineering Journal, 296, pp. 204-221.

THE MEASURENMENT OF ELECTRICITY AND DIELECTRIC CHARACTERISTIC OF ONION (ALLIUM CEPA)

This experiment aimed to measurenment of the electricity and dielectric characteristic of onion (Allium cepa). In this study, the onion have been done through the variation of frequency and temperature. The frequency was setup in 30 different values from 100 Hz -1 MHz with the temperature are from 26 0 C up to 40 0C with each increase of 2 0C. The measurement was performed on AC current in 1 kHz and input voltage is one volt. The ions through to the membrane was measured as a conductance value by using LCRmeter that connected with two pieces of AgCl electrodes on both side of the membrane. Beside that, the conductance (G) was measured by the variation temperature of the solution. The results based on the electric characteristics variation of the frequency shows that the electricity of the onion membrane from the conductance itself is tend to increase and the capacitance is decrease due to increasing of the frequency. However, the conductance and the capacitance of the soaked onion membrane is increase doe to increase of the temperature than the original onion membrane. In adddition, the increasing of conductance to temperature was plotted on ln G to 1/T curve. The slope or gradient of the curve is used to determine the change of the self-energy of the membrane and its pore radius. Self-energy of ion which obtained from non-washed and washed and soaked (with distilled water) membrane is respectively 7,66967 x 10-21 J or 0,04787 eV dan 1,2156 x 10-19 J or 0,7869 eV ( 1 joule = 6,2415 x 1018 eV) and the average of pore membrane radius is 2,00 x 10-9 meter (2,00 nm) and 1,26 10-10 meter (0,126 nm). Based on the results the onion membrane could be a good membrane for established the electrisity anf the dielectricity.

Perspectives on Thermoelectric Energy Conversion in Ion-Exchange Membranes

By thermoelectric power generation we mean the creation of electrical power directly from a temperature gradient. Semiconductors have been mainly used for this purpose, but these imply the use of rare and expensive materials. We show in this review that ion-exchange membranes may be interesting alternatives for thermoelectric energy conversion, giving Seebeck coefficients around 1 mV/K. Laboratory cells with Ag|AgCl electrodes can be used to find the transported entropies of the ions in the membrane without making assumptions. Non-equilibrium thermodynamics can be used to compute the Seebeck coefficient of this and other cells, in particular the popular cell with calomel electrodes. We review experimental results in the literature on cells with ion-exchange membranes, document the relatively large Seebeck coefficient, and explain with the help of theory its variation with electrode materials and electrolyte concentration and composition. The impact of the membrane heterogeneity and water content on the transported entropies is documented, and it is concluded that this and other properties should be further investigated, to better understand how all transport properties can serve the purpose of thermoelectric energy conversion.

Research into spontaneous activity of myocardial cells under normal and pathological conditions using the hardware and software complex based on nanosensors

Cardiovascular diseases are the leading cause of death in the world. The paper focuses on the capability of a nanosensor-based hardware and software complex (HSC) developed at Tomsk Polytechnic University to measure the activity of myocardial cells from the surface of the human body. A comparative study of nanosensors used in the HSC and conventional AgCl electrodes by FIAB Spa (Florence, Italy) was carried out. It is shown that the value of electromagnetic interference in conventional electrodes is several times higher compared to nanosensors. ECG was recorded using the developed HSC in order to show the possibility to control the activity of myocardial cells.

Voltammetric determination of leucovorin in pharmaceutical preparations using a boron-doped diamond electrode

Method for voltammetric determination of leucovorin, a drug frequently applied to decrease some unfavorable effects of anticancer drugs such as methotrexate or to increase the therapeutic effect of 5-fluorouracil, has been developed employing a bare boron-doped diamond electrode. It is the first method for leucovorin determination based on its electrochemical oxidation. Although at least three anodic and three cathodic voltammetric peaks could be recorded under the used conditions, only the anodic response situated at about + 900 mV (vs. saturated Ag|AgCl electrode) was suitable, namely due to its shape and position, for analytical purposes. Using differential pulse voltammetry with optimized parameters and supporting electrolyte of pH 3.0, the linear dynamic range of leucovorin determination was recorded from 0.15 to 25 μmol dm−3. Under such conditions, low limit of quantification of 0.050 μmol dm−3 and limit of detection of 0.015 μmol dm−3 as well was reached. Relative standard deviation calculated from 11 repeated measurements amounted to 0.7% and calculated from five repeated determinations amounting less than 3.0%. Applicability of the developed method was verified by repeated analysis of the pharmaceutical preparation with excellent results (recovery 98.7–102.8%, relative standard deviation 1.81%).

Stabilization of Glucose Oxidase and Alcohol Oxidase Based Biosensors By Immobilization in Electrochemically Generated Poly-o-Phenylenediamine Under High Hydrostatic Pressure

Electrochemical biosensors have applications in medical diagnostic, agriculture, and food. In the food industry, glucose oxidase (GOX) and alcohol oxidase (AOX) based biosensors can be valuable for real-time detection and quality control of glucose and ethanol. The global market for electrochemical biosensors are expected to reach $23.7 billion by 2022 and thousands of research papers have been published annually since 2011. However, compared to the number of publications, there are very few commercial electrochemical enzyme-based biosensors currently available on market. Glucose and lactic acid biosensors are the most common commercial devices. High price and low stability of other enzymes are arguably the two main limiting factors. Therefore, it is critical to improve the biosensor stability. Enzyme covalent immobilization, addition of solutes like sugars and polyols, and crosslinking have been used for stabilization of enzyme biosensors. High hydrostatic pressure (HHP) has also been used to stabilize enzymes but not for biosensor fabrication because upon depressurization, enzymes return to their native, less stable state. Here we report the fabrication of stabilized of GOX and AOX based biosensors using entrapment under HHP. An electrochemical cell was fabricated to fit for the HHP reactor with a custom-made electrical feed-through connectors rated to up to 700 MPa (model U111, Warsaw, Poland). Two platinum wires (diameter 0.8128 mm) were inserted into a piece of Teflon rod to be the working and counter electrode. One Ag|AgCl electrode pellet was held in a heat shrinking tube (filled with 3 M KCl) with a porous glass frit to be the reference electrode. The platinum electrodes were polished and platinized before using. GOX or AOX was entrapped by electrochemical polymerization in 5 mM o-phenylenediamine at 650 mV vs. Ag|AgCl (3 M KCl) at 0.1 to 420 MPa or 0.1 to 240 MPa, respectively. The GOX biosensors were heated at 70 °C for 180 min and amperometric response was measured at 700 mV vs. Ag|AgCl (3 M KCl) every 20 min in 20 mM glucose solution. The AOX biosensors were heated at 50 °C for 10 min and amperometric response was measured at 700 mV vs. Ag|AgCl (3 M KCl) every 2 min in 100 mM ethanol solution. The amperometric response was measured using a commercial potentiostat (Reference 600, Gamry, Warminster, PA) or a low-cost portable wireless (Bluetooth) potentiostat developed in house (ABE-stat, University of Hawaii). After 180 min, the measured current decreased to 18.8% for GOX biosensors immobilized at 0.1 MPa, while to 47.3% for those immobilized at 420 MPa. After 10 min, the measured current decreased to 23.3% for AOX biosensors immobilized at 0.1 MPa, while to 34.8% for those immobilized at 240 MPa. Electrochemical impedance spectroscopy results showed no significant difference of the charge transfer resistance between GOX biosensors immobilized at 0.1 MPa and 180 MPa. To our knowledge, this is the first report of using HHP to improve the stability of enzyme-based biosensors. In the range of 0.1 to 420 MPa or 0.1 to 240 MPa, GOX and AOX biosensor stability increased with increasing pressure, respectively. The combination of HHP with cross-linking or chemical modification to further increase the stability of enzyme based biosensors is presented as well.

Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps.

Anaesthesia for medical purposes was introduced in the 19th century. However, the physiological mode of anaesthetic drug actions on the nervous system remains unclear. One of the remaining questions is how these different compounds, with no structural similarities and even chemically inert elements such as the noble gas xenon, act as anaesthetic agents inducing loss of consciousness. The main goal here was to determine if anaesthetics affect the same or similar processes in plants as in animals and humans. A single-lens reflex camera was used to follow organ movements in plants before, during and after recovery from exposure to diverse anaesthetics. Confocal microscopy was used to analyse endocytic vesicle trafficking. Electrical signals were recorded using a surface AgCl electrode. Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested. Plants are sensitive to several anaesthetics that have no structural similarities. As in animals and humans, anaesthetics used at appropriate concentrations block action potentials and immobilize organs via effects on action potentials, endocytic vesicle recycling and ROS homeostasis. Plants emerge as ideal model objects to study general questions related to anaesthesia, as well as to serve as a suitable test system for human anaesthesia.

Evaluating the performance of Kalman filter on elbow joint angle prediction based on electromyography

High accuracy in joint angle prediction is very important in the development of devices based on myoelectric control. Joint angle prediction based on a non-pattern recognition method is more preferred due to the robustness and the easiness to adapt to any subject. This paper proposed a new method to predict an elbow joint angle based on electromyography (EMG) which used a time domain feature, zero crossing, and Kalman filter. The EMG signals were collected from biceps muscle using Ag (AgCl) electrodes. To test the proposed method, the subjects were asked to move the elbow in the flexion and extension motion at different periods of motion (12 seconds, 8 seconds and 6 seconds). The EMG features yielded from the feature extraction step were processed using a Kalman filter which was used to predict an elbow joint angle. The performance of the proposed method was evaluated using root mean squared error (RMSE) and the Pearson’s correlation coefficient (CC). In this study, the RMSE and CC values were ranged from 6.9o to 17.5o and 0.93 to 0.99 respectively. The results of the experiment have demonstrated the effectiveness of the proposed method to predict an elbow joint angle based on EMG signal.

Development of a spectro-electrochemical cell for soft X-ray photon-in photon-out spectroscopy.

We developed a spectro-electrochemical cell for X-ray absorption and X-ray emission spectroscopy, which are element-specific methods to study local electronic structures in the soft X-ray region. In the usual electrochemical measurement setup, the electrode is placed in solution, and the surface/interface region of the electrode is not normally accessible by soft X-rays that have low penetration depth in liquids. To realize soft X-ray observation of electrochemical reactions, a 15-nm-thick Pt layer was deposited on a 150-nm-thick film window with an adhesive 3-nm-thick Ti layer for use as both the working electrode and the separator window between vacuum and a sample liquid under atmospheric pressure. The designed three-electrode electrochemical cell consists of a Pt film on a SiC window, a platinized Pt wire, and a commercial Ag|AgCl electrode as the working, counter, and reference electrodes, respectively. The functionality of the cell was tested by cyclic voltammetry and X-ray absorption and emission spectroscopy. As a demonstration, the electroplating of Pb on the Pt/SiC membrane window was measured by X-ray absorption and real-time monitoring of fluorescence intensity at the O 1s excitation.

P 100 A 64-channel dry multipin-electrode cap for EEG

Multichannel Electroencephalography (EEG) is widely used in clinical neurology and neuroscientific research. EEG caps with 64 wet Silver/Silver-Chloride (Ag/AgCl) electrodes represent an often-used standard in the field. Reproducible electrode-skin contact for these electrodes is ensured by electrolyte gel or paste. Thus, these electrodes require specific mechanisms to apply and hold the gel at the electrode positions in the caps and require skilled personnel to apply the EEG cap. Dry electrodes allow more degrees of freedom in the design and fabrication of EEG caps and can be self-applied without preparation. We present a novel 64-channel EEG cap with dry electrodes. The base material of the EEG cap is a light-weight and flexible fabric, which contains small holes (perforation) making it breathable. Polyurethane (PU) based multipin electrodes serve as dry contact electrodes. A coating provides electrical conductivity of these polymer based electrodes. The use of silver coating opens the way for dry AgCl electrodes and thus, signal quality similar to wet Ag/AgCl electrodes. Thin coaxial wires are soldered to the bottom of the electrodes enabling active shielding. A second layer of fabrics protects the electrodes and the wires. Our results demonstrate that resting state EEG, eye movements, alpha activity, and pattern reversal VEP can be recorded with the novel dry 64-channel EEG cap with short preparation time and without significant differences between the novel EEG cap and a conventional cap based on wet Ag/AgCl electrodes. In conclusion, the proposed novel 64-channel EEG cap with dry electrodes can potentially replace conventional wet 64-channel EEG caps and thus enable new fields of application like brain-computer-interfaces and mobile EEG acquisition.