Synthesis of 2-(2-Fluorophenyl)-2-methylamino-Cyclohexanone as a New Ketamine Derivative

The main goal of this article is to the present research on the development of ketamine derivatives. The target molecule was a fluoroderivative of ketamine, for which a multistep synthesis has been reported. This novel ketamine derivative, 2-(2-fluorophenyl)-2-methylamino-cyclohexanone, has been called fluoroketamine by our research group. The starting fluorobenzonitrile was reacted with the appropriate Grignard reagent followed by the bromination reaction to obtain α-bromocyclopentyl-(2-fluorophenyl)-ketone. The reaction of the obtained ketone with methylamine at ?40 °C then resulted in the formation of α-hydroxycyclopentyl-(2-flourophenyl)-N-methylamine. Finally, the five-memberd ring cyclopentanol was expanded to the cyclohexylketone by a thermal rearrangement reaction. The HCl salt of the target molecule, which is soluble in water, was obtained by the acidification of the free fluoroketamine with HCl. Preliminary animal tests on mice have shown that the resulting fluoroketamine has some advantages over ketamine in terms of the effective dose and the recovery time.     

Development of a Novel Electrochemical Biosensor for Detection and Discrimination of DNA Sequence and Single Base Mutation in dsDNA Samples Based on PNA‐dsDNA Hybridization – a new Platform Technology

In spite of the extensive attention paid on the development of various DNA detection strategies, very few studies have been reported regarding direct detection of DNA sequence and mutation in dsDNA. Here, we describe the feasibility of detection and discrimination of target DNA sequences and single base mutations (SBM) directly in double‐stranded oligonucleotides and PCR products without the need for denaturation of the target dsDNA samples. This goal was achieved by employing a peptide nucleic acid (PNA) chain, self‐assembled on the gold electrode as a probe, which binds to dsDNA and forms PNA‐dsDNA hybrid.     

Homotopy analysis and differential quadrature solution of the problem of free-convective magnetohydrodynamic flow over a stretching sheet with the Hall effect and mass transfer taken into account

This paper presents an analytical solution of the problem of free-convective magnetohydrodynamic flow over a stretched sheet with the Hall effect and mass transfer taken into account. A similarity transform reduces the Navier-Stokes, energy, Ohm law, and mass-transfer equations to a system of nonlinear ordinary differential equations. The governing equations are solved analytically using an analytical method for solving nonlinear problems, namely, the homotopy analysis method. The results are compared with the results of a promising numerical method of differential quadrature developed by the authors. It is shown that there is very good agreement between analytical results and those obtained by the differential quadrature method. The differential quadrature method was validated, and the effects of non-dimensional parameters on the velocity, temperature and concentration profiles were studied.     

Seeing the Unseen: Experimental Observation of Magnetic Anapole State Inside a High-Index Dielectric Particle

The existence of non-radiating electromagnetic sources attracts much attention in photonic community and gives rise to extensive discussions of various applications in lasing, medical imaging, sensing, and nonlinear optics. In this article, the existence of magnetic anapole states (or magnetic-type non-radiating sources) characterized by a suppressed magnetic dipole radiation in a dielectric cylindrical particle is theoretically predicted and experimentally demonstrated. The specific features of the magnetic anapole state under ideal conditions are identified, followed by a demonstration of how their existence can be detected in practical structures. The concept is valid in various frequency bands from visible range for nanoparticles to microwave range for millimeter size objects. The experimental study is performed in microwave frequency range which allows not only to measure the far-field (scattered field) characteristics, but also to probe the peculiar field profile directly inside the dielectric particle. The experimental results agree well with the analytical ones and pave the way to detect and identify nontrivial different-type anapole states.     

Rapid determination of aluminum by UV-vis diffuse reflectance spectroscopy with application of suitable adsorbents

Diffuse reflectance spectroscopy (DRS) can be used as a rapid and sensitive method for the quantitative determination of low amounts of aluminum. In this analytical technique, the analyte in samples are extracted onto a solid sorbent matrix loaded with a colorimetric reagent and then quantified directly on the adsorbent surface. Alternatively, colored aluminum complexes formed in solution can also be immobilized onto adsorbent surface and be measured by DRS technique. Octadecyl silica disk, methyltrioctylammonium chloride–naphthalene and MCM-41 were examined as adsorbents. Eriochrome cyanine R and quinalizarin were used as coloring reagents. Optimal sorption conditions were found for each system of analyte–reagent–adsorbent. The concentration of analyte is determined using the appropriate form of the Kubelka–Munk function. We obtained for each of the aluminium–reagent–adsorbent system a calibration curve by plotting the absorbance versus the log 10²[Al³⁺] μg ml⁻¹. The linear dynamic range extends over two orders of magnitude within 0.01–15 μg ml⁻¹ with little differences in the range and in the correlation coefficients among the adsorbents. We consider that for a rapid determination of aluminum a spot-test-DRS combination with a detection limit of 1.0 × 10⁻² μg ml⁻¹ is the more facile and preferred technique.     

EIS and adjunct electrical modeling for material selection by evaluating two mild steels for use in super-alkaline mineral processing

The production of metal concentrates during mineral processing of ferrous and non-ferrous metals involves a variety of highly corrosive chemicals which deteriorate common mild steel as the material of choice in the construction of such lines, through rapid propagation of localized pitting in susceptible parts, often in sensitive areas. This requires unscheduled maintenance and plant shut down. In order to test the corrosion resistance of different available materials as replacement materials, polarization and electrochemical impedance spectroscopy (EIS) tests were carried out. The EIS numerical outputs were then transformed into an equivalent electric circuit using Z-View software, and the predictive behavior was contrasted with actual performance after long-term immersion, depicted through SEM, EDS, XRD and weight change observations. Also, results of pits and cracks, obtained with climax software-enhanced polarization resistance, and reduced capacitance added to much diminished current densities, verified the acceptable performance of CK₄₅ compared with high priced stainless steel substitutes with comparable operational life. Therefore, CK₄₅ can be a suitable alternative in steel constructions which are exposed to super-alkaline and corrosive environments.     

NMR study of the stoichiometry and stability of complexation reaction between Mg2+, Ca2+, Sr2+ and Ba2+ ions and 60-crown-20 in binary acetonitrile solvent mixtures

Proton nuclear magnetic resonance (¹H-NMR) spectroscopy was used to study the complexation reaction between Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ ions and 60-crown-20 in a series of binary mixtures of deuterated acetonitrile (AN), nitromethane (NM) and D₂O at 27?°C. Formation constants of the 1:1 complexes were determined through computer fitting of the chemical shift/mol ratio data and found to vary in the order of Ba²⁺?>?Sr²⁺?>?Mg²⁺?≈?Ca²⁺. The influence of the solvent composition on the stability of the resulting complexes was also discussed. In all cases, the changes in the stability constants with the solvent composition were monotonic and showed a good correlation with the inherent solvation ability of the pure solvents which form the mixture.