Dual Electrode Research Articles

A New Device Structure Yttria-Stabilized Zirconia-Based Mixed Potential Gas Sensor for Volatile Organic Compounds Gas Classification

In this work, a new device structure mixed potential gas sensor constructed with two sensitive electrodes, one counter electrode and one reference electrode was fabricated for Volatile Organic Compounds (VOC) classification. The construction of two sensitive electrodes enables one sensor to produce two outputs signal for the analyte. And the gas-sensitive performance of the sensor could be adjusted by applying different bias voltage on the counter electrode. The above methods could generate more sensing features, which makes it possible to replace sensor array with a single sensor. The output signal was further feature extracted and used to train the K-Nearnest Neighbor (KNN) machine learning model. The results of the classification shows that constructing a double electrode and applying a bias voltage could significantly enhances the discrimination ability of the sensor for different gases. By designing dual electrodes and counter electrode, a single sensor is realized instead of sensor array. It is important for the realization of artificial olfaction.

Dual Gold-Nanoslit Electrodes for Ultrasensitive Detection of Antigen-Antibody Reactions in Electrochemical Surface Plasmon Resonance.

We present the use of surface charges in dual gold-nanoslit electrodes to improve the surface plasmon resonance (SPR) detection limit by several orders of magnitude. The SPR is directly generated by gold-nanoslit arrays in the two electrodes. The SPR shifts for both nanoslit arrays are measured simultaneously with a simple hyperspectral setup. When biomolecules are captured by specific antibodies on the dual electrodes, the surface charge is changed during the electrochemical process due to the increase in surface impedance. The push-pull-type electrodes generate opposite surface charges. Using the differences in both spectral shifts, the change in surface charge is detected sensitively. We demonstrate that using a [Fe(CN)6]3-/4- redox process after antigen-antibody interactions, the dual nanoslit electrodes show an enhancement of the detection limit from 1 μg/mL to 10 pg/mL.

Full-array channel discrimination in cochlear implants: validation and clinical application

Objective We sought to validate our proposed tool for estimating channel discrimination of cochlear implant (CI) users along the full electrode array and to assess associations between place-pitch discrimination and speech perception. Design In two tests, participants identified one stimulus (probe) as the odd-one-out compared with two reference stimuli. Probe stimuli were evoked using dual electrode stimulation characterised by the current steering coefficient α. The first test measured psychometric functions (PFs) on pre-defined contacts, with just a noticeable difference (JNDα) as the outcome variable. The second test estimated channel discrimination on the full electrode array, yielding a discrimination score of Dα. We measured speech perception as free-field consonant-vowel-consonant phoneme recognition scores. Study sample We included 25 adults with at least 6 months of CI experience. Results JNDα and Dα scores measured on the same contact correlated significantly (rs = 0.64, p < 0.001). Mean JNDα and speech perception scores showed significant relationships in quiet and in noise. Conclusions Dα correlated strongly with JNDα scores obtained with the PFs. For poor performers, the full-array test may underestimate JNDα. The full-array pitch discrimination test could be a helpful clinical tool, such as for fitting regions of lesser pitch discrimination ability.

Electrochemical Response of Mixed Conducting Perovskite Enables Low-Cost High-Efficiency Hydrogen Sensing.

High-performance noble metal-free gas sensors are crucial for widespread applications in various areas. Non-Nernstian electrochemical sensors have attracted tremendous attention, but are limited by the high cost and low efficiency of Pt electrode. Moreover, responses from different electrodes usually have the same polarity, degrading the sensor performance. Here we report a reverse response on a series of mixed ionic-electronic conductors (MIECs). Exemplary SrFe0.5Ti0.5O3-δ (SFT50) perovskite shows excellent H2 sensing properties, including high sensitivity and selectivity, humidity resistance, and long-term stability. Strikingly, the response is positive, as opposed to the usual one. Such an unusual response is ascribed to the change of the surface electrostatic potential due to the gas chemical reaction, which outcompetes traditional mechanisms, thereby reversing the response polarity. A conceptual noble-metal-free sensor with dual oxide electrodes of opposite polarity is designed by substituting SFT50 for the benchmark Pt, achieving a 1.5-2.0× increase in H2 response, sensitivity, and selectivity and a low limit of detection of 16 ppb. The ideal unity of excellent sensing and unusual polarity for MIECs can be used to optimize the performance of a variety of conventional sensors while reducing the cost. Our findings provide new insights into electrochemical gas sensing and offer a facile approach for developing low-cost high-performance gas sensors.

Failed shocks in hypertrophic cardiomyopathy patients: prevalence, predictors and outcome

Abstract Funding Acknowledgements Type of funding sources: None. Introduction An implantable cardioverter-defibrillator (ICD) is used in selected high-risk hypertrophic cardiomyopathy (HCM) patients in order to prevent sudden arrhythmic death. The unique features of this population raise concerns regarding the reliability of successful defibrillation. Purpose To describe the rate and discover potential predictors of failed shocks in HCM patients. Methods We retrospectively evaluated all HCM patients with an ICD from a single tertiary medical center. Clinical, electrocardiographic and echocardiographic data were collected and compared among patients with and without failed shocks. Results A total of 99 patients (77% male, 45±17 years old) were analyzed. Over a median follow up of 6.3 years (IQR 2.6-10.7), 20 patients developed sustained ventricular arrhythmia (VTA). Of those, 18 patients received appropriate shocks from their ICD. VTA was associated with younger age at diagnosis, history of syncope and thicker maximal LV width. Six patients experienced at least one failed shock. The likelihood of failed shocks was similar when single or dual coil electrodes were used (dual coils in 67% of patients with failed shocks and 50% in those without), and the only predictor was increased wall thickness [OR 1.2 (1.07-1.38) per 1 mm]. All-cause mortality was low and similar in patients with an without failed shocks (0% vs 8%, P=0.5) Conclusions Failed shocks are a rare entity in HCM patients. Increased maximal LV width was the only predictor of those events. Our findings support avoiding defibrillation threshold testing routinely, but may indicate its need in patients with extreme LV wall thickening (≥23 mm).

Simultaneous electrochemical immunosensing of relevant cytokines to diagnose and track cancer and autoimmune diseases

This work reports the first dual magnetic beads (MBs) assisted immunoplatform for the simultaneous determination of BAFF (B cell activation factor) and APRIL (a proliferation-induced ligand), two cytokines related to immunity and tumour invasion, growth and metastasis. The electrochemical immunoplatform involves sandwich-type immunoassays implemented on magnetic microparticles functionalized with neutravidin (NA-MBs) or carboxylic groups (HOOC-MBs), and amperometric detection (Eapp = − 0.20 V vs. Ag pseudo-reference electrode) at screen-printed dual carbon electrodes (SPdCE) using the H2O2/hydroquinone (HQ) system. The developed immunosensors provide improved sensitivity, with LOD values of 0.33 and 16.4 pg mL−1 for BAFF and APRIL, respectively, and much shorter assay time that those claimed for ELISA kits and allow their simultaneous determination. The dual immunosensor permits discrimination between healthy individuals and patients diagnosed with Systemic Lupus Erythematosus (SLE) or colorectal cancer (CRC) through the determination of both cytokines in 100-times diluted human sera with results in agreement with those provided by the individual ELISA methodologies.

Additive-Assisted Hydrophobic Li+ -Solvated Structure for Stabilizing Dual Electrode Electrolyte Interphases through Suppressing LiPF6 Hydrolysis.

Lithium-metal batteries have attracted much attention due to their high energy density. However, the hydrolysis of LiPF6 leads to uncontrollable Li dendrites growth and fast capacity fading. Herein, a hydrophobic Li+ -solvated structure is designed by inducing the hexafluoroisopropyl acrylate into the electrolyte system. Due to the alkene groups and non-polar perfluorocarbon (-CF2 CF2 CF3 ) chain, a hydrophobic surface around Li-ion solvated aggregates can be obtained to protect the LiPF6 against the attack from trace H2 O. Moreover, the additive could also help to form an organic solid electrolyte interphase with rich polar C-F bonds, which can capture Li ions to restrain the dendrite growth. Therefore, the Li||Li symmetric cells show a stable cycling performance up to 500 h at a current density of 1 mA cm-2 . The Li||LiNi0.6 Co0.2 Mn0.2 O2 cells show good cycling stability, exhibiting a specific capacity of 111 mAh g-1 at 1 C with a capacity retention of 74 % after 200 cycles.

Additive‐Assisted Hydrophobic Li+‐Solvated Structure for Stabilizing Dual Electrode Electrolyte Interphases through Suppressing LiPF6Hydrolysis

AbstractLithium‐metal batteries have attracted much attention due to their high energy density. However, the hydrolysis of LiPF6leads to uncontrollable Li dendrites growth and fast capacity fading. Herein, a hydrophobic Li+‐solvated structure is designed by inducing the hexafluoroisopropyl acrylate into the electrolyte system. Due to the alkene groups and non‐polar perfluorocarbon (−CF2CF2CF3) chain, a hydrophobic surface around Li‐ion solvated aggregates can be obtained to protect the LiPF6against the attack from trace H2O. Moreover, the additive could also help to form an organic solid electrolyte interphase with rich polar C−F bonds, which can capture Li ions to restrain the dendrite growth. Therefore, the Li||Li symmetric cells show a stable cycling performance up to 500 h at a current density of 1 mA cm−2. The Li||LiNi0.6Co0.2Mn0.2O2cells show good cycling stability, exhibiting a specific capacity of 111 mAh g−1at 1 C with a capacity retention of 74 % after 200 cycles.

Redox Homeostasis Alteration in Endothelial Mechanotransduction Monitored by Dual Stretchable Electrochemical Sensors.

In vivo, endothelial cells are permanently subjected to dynamic cyclic stretch and adapt to it through the release of vasoactive substances. Among them, reactive oxygen species (ROS) and nitric oxide (NO) are indispensable redox molecules, the contents of which and their ratio are closely implicated with endothelial redox homeostasis. However, simultaneous and quantitative monitoring of ROS and NO release in endothelial mechanotransduction remains a great challenge. Herein, a stretchable electrochemical device is developed with a dual electrode based on gold nanotubes decorated with uniform and tiny platinum nanoparticles. This hybrid nanostructure endows the sensor with high sensitivity toward both hydrogen peroxide (H2O2) (as the most stable ROS) and NO electrooxidation. Importantly, the two species can be well discriminated by applying different potentials, which allows simultaneous monitoring of H2O2 and NO release in stretch-induced endothelial mechanotransduction by the same device. The results of quantitative analysis suggest that endothelial redox homeostasis and its alteration are strongly related to vascular biomechanical and biochemical milieus. Further investigation reveals that the interplay of ROS and NO signaling has an important role in the regulation of endothelial redox state. This work will greatly facilitate the deep understanding of the molecular mechanism of endothelial dysfunction and vascular disorder.

Separator-Wetted, Acid- and Water-Scavenged Electrolyte with Optimized Li-Ion Solvation to Form Dual Efficient Electrode Electrolyte Interphases via Hexa-Functional Additive.

The performance of lithium metal batteries (LMBs) is determined by many factors from the bulk electrolyte to the electrode‐electrolyte interphases, which are crucially affected by electrolyte additives. Herein, the authors develop the heptafluorobutyrylimidazole (HFBMZ) as a hexa‐functional additive to inhibit the dendrite growth on the surface of lithium (Li) anode, and then improve the cycling performance and rate capabilities of Li||LiNi0.6Co0.2Mn0.2O2 (NCM622). The HFBMZ can remove the trace H2O and HF from the electrolyte, reducing the by‐products on the surface of solid electrolyte interphase (SEI) and inhibiting the dissolution of metal ions from NCM622. Also, the HFBMZ can enhance the wettability of the separator to promote uniform Li deposition. HFBMZ can make Li+ easy to be desolvated, resulting in the increase of Li+ flux on Li anode surface. Moreover, the HFBMZ can optimize the composition and structure of SEI. Therefore, the Li||Li symmetrical cells with 1 wt% HFBMZ‐contained electrolyte can achieve stable cycling for more than 1200 h at 0.5 mA cm–2. In addition, the capacity retention rate of the Li||NCM622 can reach 92% after 150 cycles at 100 mA g–1.

Ultrasensitive detection of soy traces by immunosensing of glycinin and β-conglycinin at disposable electrochemical platforms.

This work reports the first electrochemical bioplatform for the determination of soy traces in food. The bioplatform involves sandwich-type immunoassays using specific antibodies for β-conglycinin and glycinin, which are the main allergenic soy proteins, and carboxylic acid-modified magnetic microbeads. Amperometric detection at -0.20V (vs. an Ag pseudo-reference electrode) was performed using single or dual screen-printed carbon electrodes and the H2O2/hydroquinone (HQ) system. The measured variation in the cathodic current was directly proportional to the concentration of target allergenic proteins. The developed bioplatforms exhibit a good selectivity and sensitivity providing limits of detection (LOD) values of 0.03 and 0.02ngmL-1 for β-conglycinin and glycinin, respectively. The determination of both proteins can be carried out in only 1.5h. The electrochemical bioplatforms allow their accurate determinations (with results statistically comparable to those provided by ELISA methodologies) in raw cookie dough and baked cookies enriched with soy flour. The results obtained confirm, in a pioneering way with electrochemical biosensors, the possibility of discriminating samples incurred with as little as 0.0005ppm of a food allergen in model cookie extracts.

Electrochemical exfoliation of graphene using dual graphite electrodes by switching voltage and green molten salt electrolyte

In this study, the switching voltage (sV) technique was applied for graphite exfoliation in eutectic molten salts of NaOH and KOH at 300 °C. Dual graphite pencil cores were used as anode and cathode with two commercial time relays to swap between positive and negative voltages at various application times. The exfoliated graphene samples were analyzed using several characterization techniques. Results indicated that the sV technique was efficient to achieve better exfoliation efficiency compared to the constant voltage (cV). At the optimum voltage application times for anode and cathode relays, few-layer graphene with respective high production yields of 0.50 and 0.43 g min−1, low ID/IG ratios of 0.31 and 0.58, and good electrical conductivities of 75.28 and 182.62 S m−1 were obtained on both anode and cathode, respectively. Moreover, the SEM characterizations showed that the sV technique efficiently produced smooth graphene flakes, with less agglomeration, crumbling, and wrinkling than those exfoliated at a constant voltage. The XRD patterns confirmed that the crystallite size of the exfoliated graphene prepared by the sV method was smaller than those of pristine graphite and the graphene obtained at a cV. The AFM analysis revealed that the thickness of the exfoliated graphene developed by the sV technique was significantly lower than that obtained at cV. The XPS analysis showed that the quality and the purity of the exfoliated graphene obtained using the sV technique was higher than that prepared at a constant voltage due to the effective suppressing of the cations and ions stacking between the graphite layers.

Design and analysis of dopingless 1T DRAM using work function engineered tunnel field effect transistors

In this paper, a dopingless DRAM based on work function engineered Tunnel field effect transistor is proposed. Gate metal workfunction engineering is done to enhance ON/OFF current ratio of drain current, thereby improving the sense margin and retention time. Drain electrode is made up of dual metal, so as to suppress ambipolar current. The analysis of dual material gate dual drain electrode DRAM (DMG DDE DRAM) and triple material gate dual drain electrode DRAM (TMG DDE DRAM) is done in terms of retention time and sense margin. The performance parameters with different device dimensions and bias conditions are analyzed. It is observed that the proposed DRAMs work well even when the dimensions are scaled down. In addition, the proposed DRAMs have comparable performance with the conventional DRAMs and provide better performance when compared with other dopingless DRAM. Retention times of 430 ms and 370 ms, sense margins of 130 nA and 101 nA are achieved with TMG DDE DRAM and DMG DDE DRAM respectively.

Binary MoS2 nanostructures as nanocarriers for amplification in multiplexed electrochemical immunosensing: simultaneous determination of B cell activation factor and proliferation-induced signal immunity-related cytokines

A dual immunosensor is reported for the simultaneous determination of two important immunity-related cytokines: BAFF (B cell activation factor) and APRIL (a proliferation-induced signal). Sandwich-type immunoassays with specific antibodies (cAbs) and a strategy for signal amplification based on labelling the detection antibodies (dAbs) with binary MoS2/MWCNTs nanostructures and using horseradish peroxidase (HRP) were implemented. Amperometric detection was carried out at screen-printed dual carbon electrodes (SPdCEs) through the hydroquinone HQ/H2O2 system. The developed dual immunosensor provided limit of detection (LOD) of 0.08 and 0.06 ng mL−1 for BAFF and APRIL, respectively, and proved to be useful for the determination of both cytokines in cancer cell lysates and serum samples from patients diagnosed with autoimmune diseases and cancer. The obtained results agreed with those found using ELISA methodologies.Graphical abstract

Gold nanourchin enhances detection of Alzheimer's disease biomarker "miRNA-137" on dual electrode sensing surface.

Diagnosis of Alzheimer's disease (AD) is a complex task, and at present, neuroimaging such as magnetic resonance imaging and positron emission tomography is commonly used for the diagnosis of AD. This research work developed a new biosensing method with gold nanomaterial to identify AD biomarker of miRNA-137. Gold nanourchin (GNU) was attached on the interdigitated electrode through the silane linker and COOH-ended capture oligonucleotide was immobilized on the GNU surface. This surface helps to quantify the target sequence of miRNA-137 and the detection limit reached to 0.01pM on the linear range of 0.01-100pM. With 3δ calculation on the linearity, the determination coefficient was noticed as y=1.2867x-2.2697; R2 =0.9059. The control performances did not show a significant response, indicating the specific identification of target.

Improved degradation of tetracycline, norfloxacin and methyl orange wastewater treatment with dual catalytic electrode assisted self-sustained Fe2+ electro-Fenton system: Regulatory factors, mechanisms and pathways

The environmental hazards associated with the presence of antibiotics and dyes in water sources require the development of efficient and appropriate wastewater treatment technologies. In the research, a dual catalytic electrode assisted self-sustained Fe2+ electro-Fenton system was constructed to degrade tetracycline, norfloxacin and methyl orange in wastewater efficiently and economically. The novel titanium mesh based PbO2/SnO2 anode electrode was prepared by electrodeposition with the best oxidation performance at the ratio of Sn to Pb 0.5:1, and silver doped Zinc-based organic framework ([email protected]) mixed crystal cathode catalyst was synthesized by precipitation at room temperature. Meanwhile, a sacrificial iron anode was introduced into the system in an acidic solution without a power supply, realizing the endogenous supply of Fe2+. The results indicated that the process was capable of self-supporting H2O2 and Fe2+ under the optimized conditions of pH range of 3.5–4.0, iron area of 10 cm2 and current intensity of 9 mA. The current efficiency was calculated to be as high as 369.5%. The type of conductive substrate supported cathode catalyst is an important factor determining the performance of the novel coupled electric-Fenton system. Electro-Fenton system using [email protected] catalytic electrode loaded with conductive substrates (stainless steel mesh (SS), carbon felt (CF), and activated charcoal granules (ACG)) was constructed to degrade tetracycline (TC), with the degradation efficiencies of 100% (k = 0.03048), 99.7% (k = 0.01831), 99.7% (k = 0.01421). Moreover, the experiment group of [email protected] electrode had achieved good degradation effects for TC, norfloxacin (NOR), methyl orange (MO), and the degradation efficiency was 99.1%, 92.8% and 100%, respectively. The possible degradation pathways of TC, NOR and MO were proposed by analyzing the intermediates. This work demonstrates the scaling-up potential of the system in the treatment of antibiotics and dye wastewater.

Transparent ultrathin Ag nanomesh electrode fabricated by nanosphere lithography for organic light-emitting devices

We report a transparent ultrathin Ag nanomesh electrode fabricated by nanosphere lithography combined with a dielectric wetting layer, which is simple and cost-effective. Compared with the continuous ultrathin film Ag electrode, the nanomesh electrode exhibits a higher figure of merit (FOM = T10/Rs, T is the transmittance and Rs is the sheet resistance) of 3.01 × 10−3 Ω−1, which is due to the retained high electrical conductivity and nanopores as optical windows. The maximum luminance and current efficiency enhancement of organic light emitting devices (OLEDs) with an ultrathin Ag nanomesh electrode are up to 56.2% and 41.4% compared to that of conventional devices with an ITO anode. It is worth noting that the ultrathin Ag nanomesh electrode has been proved able to resolve the emission intensity roll-off of OLEDs with dual metal electrodes as the enlargement of viewing angle due to the redistribution of the light emission direction derived from strong scattering. More light emission at larger angles is of great value for lighting panel applications.

Electrically tunable large aperture liquid crystal lens with dual hole-patterned electrodes

An electrically tunable large aperture liquid crystal (LALC) lens consisting of dual hole-patterned electrodes with different diameters is demonstrated. The proposed LALC lens can realize a tunable focal length and a switchable optical aperture by changing the driving models (DM). The experimental results show that the focal length of the LALC lens ranges from 325 mm to 220 mm when the operating voltage is changed from 24 V to 66 V by DM1, and it varies from 310 mm to 200 mm with the supplied voltages of 24–59 V by DM2. The optical aperture of the LALC lens can be switched between 4 mm-diameter and 5 mm-diameter. Furthermore, the turn-on time is significantly decreased by the over-driving method. Because of its low root mean square (RMS) error (<0.08 λ), the LALC lens, as an ideal optical lens, can exhibit excellent imaging performance in the optical imaging system. These results demonstrate that the proposed LALC lens has potential applications in the fields of imaging, biometrics and optical data storage because of its tunable focal length and switchable optical apertures.

Growing Co–Ni–Se nanosheets on 3D carbon frameworks as advanced dual functional electrodes for supercapacitors and sodium ion batteries

The reasonable design of electrode materials is crucial for tuning the electrochemical performances of advanced energy storage systems.

Dual Pallidal and Thalamic Deep Brain Stimulation for Complex Ipsilateral Dystonia.

PurposeGlobus pallidus pars interna (GPi) has become an established target for deep brain stimulation (DBS) in dystonia. Previous studies suggest that targeting the ventralis oralis (Vo) complex nucleus improves dystonic tremor or even focal dystonia. Research has also demonstrated that multi-target DBS shows some benefits over single target DBS. In this study, we reviewed patients who had undergone unilateral DBS targeting the GPi and Vo.Materials and MethodsFive patients diagnosed with medically refractory upper extremity dystonia (focal or segmental) underwent DBS. Two DBS electrodes each were inserted unilaterally targeting the ipsilateral GPi and Vo. Clinical outcomes were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Disability Rating Scale.ResultsBFMDRS scores decreased by 55% at 1-month, 56% at 3-month, 59% at 6-month, and 64% at 12-month follow up. Disability Rating Scale scores decreased 41% at 1-month, 47% at 3-month, 50% at 6-month, and 60% at 12-month follow up. At 1 month after surgery, stimulating both targets improved clinical scores better than targeting GPi or Vo alone.ConclusionUnilateral thalamic and pallidal dual electrode DBS may be as effective or even superior to DBS of a single target for dystonia. Although the number of patients was small, our results reflected favorable clinical outcomes.