In this study, a novel, simple and sensitive square wave voltammetric method for the determination of elbasvir (ELB) using Mn₅O₈-modified pencil graphite electrode (PGE) was developed. Mn₅O₈ nanoparticles (NPs) were synthesized by calcination of manganese malonate at 350 °C for 24 h. The structure of Mn₅O₈ was characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) and Raman spectroscopy. Nitrogen adsorption-desorption measurements showed that Mn₅O₈ NPs possess a mesoporous structure with a specific surface area of ~32 m²/g. After characterization, Mn₅O₈ NPs were applied to the electrode surface in a “drop-casting” fashion. Scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) were employed to investigate the differences between the Mn₅O₈-decorated PGE and bare PGE. Under the optimized experimental conditions, the modified PGE gives a linear response over the concentration range of 0.20 to 3.00 μmol L⁻¹ ELB with low limits of detection and quantitation, which were found to be 0.04 and 0.13 μmol L⁻¹, respectively. For the first time, the photo-stability and the photo-induced dimeric-monomeric conversion behavior of ELB were studied using FT-IR, spectrophotometric, spectrofluorimetric and mass spectroscopic techniques. The fabricated electrode exhibits good precision, selectivity, and sensitivity that could be applied successfully for sensitive determination of ELB in its bulk form, in quality control laboratories and biological fluids.

A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO₂-modified graphite electrode. Two different MnO₂ polymorphs (γ- and ε-MnO₂nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO₂ NPs have large surface area of 345 m²/g, which is extremely high if compared to that of γ-MnO₂ NPs (38 m²/g). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either γ- or ε-MnO₂ NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO₂ NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO₂ NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO₂/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO₂/PGE provides a linear response over the concentration range of 0.025–3.60 μmol L⁻¹ LED with a low limit of detection, which was found to be 5.10 nmol L⁻¹(4.50 ng mL⁻¹) for the 1^st peak and 9.20 nmol L⁻¹ (8.10 ng mL⁻¹) for the 2^nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-IR and LC/MS. The fabricated sensor exhibits a good precision, selectivity and stability and was applied successfully for the determination of LED in its tablets and real rat plasma samples with a good recovery using a simple extraction technique.

r group is developing an ultra-compact neutron source based on inertial electrostatic confinement (IEC) fusion device for various applications at Kyoto University. This IEC device is configured from a titanium anode and a molybdenum cathode with diameters of 17 and 6 cm, respectively. A high-intensity neutron source operated in a stable pulse shape is mandatory to increase the system’s reliability. Applying a higher voltage is a straightforward way to increase the neutron yield from the system. However, a contradiction between the increase of the applied voltage and the reduction of the system size limits such a proposal. A three-stage feedthrough system is employed in the developed compact IEC to address this contradiction. A feedback control system was developed and applied to the input and output parameters, such as the applied voltage and the neutron yield, to increase its stability in long-term operation. Characterization of the developed system was performed by scanning the neutron yield as a function of applied voltage and cathode current. To date, a maximum neutron yield of 9.2 × 10⁷n·s^–1 at 6.4 kW (80 kV and 80 mA) has been obtained. A study of the feasibility of using the IEC system for neutron radiography was performed. Preliminary analysis of the resulting images showed there was good contrast between the sample and the background. The results suggest that optimization of the experimental parameters is needed to perform higher accuracy neutron radiography.

A discharge-type fusion neutron source generates neutrons by fusion reactions of hydrogen isotope atoms. In order to operate the fusion device based on the deuterium–tritium (D–T) fusion reaction, the tritium inventory is required to be decreased. In the present work, a self-sufficient system was installed into the fusion device for reducing the amount of hydrogen isotope fuel gas. The fuel gas was supplied and recovered with an intermetallic compound ZrCo in a sealed chamber in this system. A deuterium–deuterium operation was maintained for more than 60 min with stable discharge voltages, and the temperature of the ZrCo bed was changed to improve the neutron production rate. Factors that influenced the pressure inside the chamber were determined and optimized. Gas analysis using a quadrupole mass spectrometer indicates a dilution of the deuterium fuel was caused by hydrogen isotope exchange …