All-Solid-State Carbon Black Paste Electrodes Modified by Poly(3-octylthiophene-2,5-diyl) and Transition Metal Oxides for Determination of Nitrate Ions.

This paper presents new paste ion-selective electrodes for the determination of nitrate ions in soil. The pastes used in the construction of the electrodes are based on carbon black doped with transition metal oxides: ruthenium, iridium, and polymer-poly(3-octylthiophene-2,5-diyl). The proposed pastes were electrically characterized by chronopotentiometry and broadly characterized potentiometrically. The tests showed that the metal admixtures used increased the electric capacitance of the pastes to 470 µF for the ruthenium-doped paste. The polymer additive used positively affects the stability of the electrode response. All tested electrodes were characterized by a sensitivity close to that of the Nernst equation. In addition, the proposed electrodes have a measurement range of 10-5 to 10-1 M NO3- ions. They are impervious to light conditions and pH changes in the range of 2-10. The utility of the electrodes presented in this work was demonstrated during measurements directly in soil samples. The electrodes presented in this paper show satisfactory metrological parameters and can be successfully used for determinations in real samples.

Modification of Carbon Nanomaterials by Association with Poly(3-octylthiophene-2,5-diyl) as a Method of Improving the Solid-Contact Layer in Ion-Selective Electrodes.

A new group of carbon nanomaterials modified with poly(3-octylthiophene-2,5-diyl) for solid-contact layers in ion-selective electrodes was obtained. The materials were characterized by scanning electron microscopy and measurement of the contact angle. The modification greatly improved the hydrophobicity of the materials, and the highest contact angle (175°) was obtained for a polymer-modified carbon nanofibers/nanotube nanocomposite. The electrical parameters of the electrodes were determined using the methods of chronopotentiometry and electrochemical impedance spectroscopy. The highest electrical charge capacity was obtained for polymer-modified carbon nanofibers (7.87 mF/cm2). For this material, the lowest detection limit (10-6.2 M) and the best potential reversibility (SD = 0.2 mV) were also obtained in potentiometric measurements.

Hierarchical Nanocomposites Electrospun Carbon NanoFibers/Carbon Nanotubes as a Structural Element of Potentiometric Sensors.

This work proposes new carbon materials for intermediate layers in solid-contact electrodes sensitive for potassium ions. The group of tested materials includes electrospun carbon nanofibers, electrospun carbon nanofibers with incorporated cobalt nanoparticles and hierarchical nanocomposites composed of carbon nanotubes deposited on nanofibers with different metal nanoparticles (cobalt or nickel) and nanotube density (high or low). Materials were characterized using scanning electron microscopy and contact angle microscopy. Electrical parameters of ready-to-use electrodes were characterized using chronopotentiometry and electrochemical impedance spectroscopy. The best results were obtained for potassium electrodes with carbon nanofibers with nickel-cobalt nanoparticles and high density of nanotubes layer: the highest capacity value (330 µF), the lowest detection limit (10-6.3 M), the widest linear range (10-6-10-1) and the best reproducibility of normal potential (0.9 mV). On the other hand the best potential reversibility, the lowest potential drift (20 µV·h-1) in the long-term test and the best hydrophobicity (contact angle 168°) were obtained for electrode with carbon nanofibers with cobalt nanoparticles and high density of carbon nanotubes. The proposed electrodes can be used successfully in potassium analysis of real samples as shown in the example of tomato juices.

Intravaginal electrical stimulation as a monotherapy for female stress urinary incontinence: A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: Since patients, physiotherapists and gynaecologists continue to seek effective conservative treatments for stress urinary incontinence (SUI), the aim of this systematic review and meta-analysis was to determine the therapeutic efficacy of intravaginal electrical stimulation (ES) in women with SUI. METHODS: We searched PubMed, Embase, EBSCOHost and Ovid for randomized controlled trials. For dichotomous data, we calculated the risk ratio (RR) and 95% confidence interval (CI). For continuous data, we calculated the mean difference (MD) and 95% CI. Heterogeneity was assessed with I2 statistics. RESULTS: Of the 686 records identified, a total of 10 articles met the inclusion criteria. A meta-analysis revealed significant differences between the ES and no active treatment groups in the pooled objective cure rates (RR: 4.20; 95% CI: 1.70 to 10.40; p = 0.001; I2 = 0%) and subjective cure or improvement rates (RR: 4.96; 95%: 1.01 to 24.37; p = 0.04; I2 = 0%). No significant differences were found in the pooled number of incontinence episodes per 24 h (MD: 0.16; 95% CI: 0.68 to 0.37; p = 0.56; I2 = 0%), the pooled Incontinence Quality of Life Questionnaire scores (MD: 1.84; 95% CI: 2.11 to 5.80; p = 0.36; I2 = 0%) or the pooled number of adverse effects (RR: 0.69; 95% CI: 0.38 to 1.27; p = 0.23; I2 = 0%) between the ES and other conservative treatment groups. CONCLUSION: There was insufficient evidence for or against the use of intravaginal ES therapy for women with SUI, partly due to the variability in the interventions of the included trials and the small number of trials included.

Graphene Flakes Decorated with Dispersed Gold Nanoparticles as Nanomaterial Layer for ISEs.

This paper proposes a new type of solid-contact layer based on graphene/gold nanoparticles for ion-selective electrodes. A novel approach to preparing the material for intermediate layer by modifying the graphene flakes by gold nanoparticles is presented. With this approach, we observed a large surface area of material and in consequence high electrical capacitance of electrodes. We have obtained satisfactory results demonstrating that the modification of graphene with gold allows for enhancing electrical and wetting properties of carbon nanomaterial. Electrical capacitance of designed nanocomposite-contacted electrode equals to approximately 280 µF, which in consequence ensures great long-term potential stability defined by the potential drift of 36 µV/h. The modification of graphene with nanoparticles completely changed its wetting properties, as the designed material turned out to be hydrophobic with a water contact angle of 115°. Graphene/gold nanoparticles-contacted electrodes are insensitive to the changing light conditions, exhibiting near-Nernstian response in the potassium concentration range between 10-5.9 M and 10-1 M of K+ ions and may be applied in the pH range between 2 and 10.5.