Piperazine‐functionalized nickel ferrite nanoparticles as efficient and reusable catalysts for the solvent‐free synthesis of 2‐amino‐4H‐chromenes

Piperazine‐functionalized nickel ferrite (NiFe₂O₄) nanoparticles were synthesized as recoverable heterogeneous base catalysts using a routine method. The synthesized materials were characterized using various spectroscopic techniques such as infrared, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray, thermogravimetry analysis, and vibrating sample magnetometry. Catalytic efficiency was investigated in the synthesis of 2‐amino‐4H‐chromene derivatives via a one‐pot three component reaction of aldehyde and malononitrile with β or α‐naphthol/5‐methyle resorcinol under solvent‐free conditions with good to high yields. This method is operationally simple and has several advantages such as good to high yield, short reaction times, solvent‐free conditions, and easy synthesis. Moreover, the catalyst was recovered easily using an external magnet and reused three times without distinctive loss in catalytic activity.     

Electrochemical Derivatization of Acetaminophen for Indirect Determination of Eflornithine Using β‐CD Modified Glassy Carbon Electrode

In the present work, the oxidation of acetaminophen in the absence and presence of eflornithine was electrochemically investigated by means of cyclic voltammetry at a glassy carbon electrode (GCE). Our results indicate that N‐acetyl‐p‐benzoquinone imine (NAPQI) produced from two‐electron electrochemical oxidation of acetaminophen participates in a Michael addition reaction with eflornithine via an ECE mechanism. This fact was used for the determination of eflornithine using differential pulse voltammetry (DPV) technique on the surface of β‐Cyclodextrin modified glassy carbon (β‐CD/GC) electrode. β‐CD/GC electrode was prepared through an electrodeposition procedure and characterized by Fourier‐transform infrared spectroscopy (FT‐IR), Cyclic Voltammetry (CV), Field Emission Scanning Electron Microscopy (FESEM) and Energy‐dispersive X‐ray spectroscopy (EDS) techniques. Under optimum conditions, the β‐CD/GC electrode showed a good linearity as a function of the eflornithine concentration over the range from 5 to 100 μM with detection limit and quantification limit of 1.94 and 5.8 μM, respectively. Finally, the proposed protocol was confirmed to be successful in determination of eflornithine in human urine samples with good recovery, ranging from 97.2 % to 104.8 %.     

Development and application of SBA‐15 assisted electromembrane extraction followed by corona discharge ion mobility spectrometry for the determination of Thiabendazole in fruit juice samples

A new sample preparation method based on SBA‐15 assisted electromembrane extraction coupled with corona discharge ion mobility spectrometer was developed for the determination of Thiabendazole as a model basic pesticide in fruit juice samples. The addition of SBA‐15 in the supported liquid membrane in electromembrane extraction system not only can lead to enhancement of the effective surface area, but also introducing the negatively charged silanol groups into supported liquid membrane might improve migration of positively charged analytes toward the supported liquid membrane and finally into the acceptor solution. To investigate the effect of the presence of SBA‐15 in the supported liquid membrane on the extraction efficiency, a comparative study was carried out between the conventional electromembrane extraction and SBA‐15/electromembrane extraction methods. Under the optimized conditions, SBA‐15/electromembrane extraction method showed higher extraction efficiencies in comparison with conventional electromembrane extraction method. SBA‐15/electromembrane extraction method exhibited a low limit of detection (0.9 ng/mL), high preconcentration factor (167) and high recovery (83%). Finally, the applicability of SBA‐15/electromembrane extraction method was studied by the extraction and determination of Thiabendazole as a model basic pesticide in fruit juice samples.     

Systematic Study of Two-Quasi-Particle Structure of Odd–Odd Thulium Nuclei

Physics of Atomic Nuclei - In this study, the nuclear structure properties of $${}^{160{-}166}$$ Tm isotopes with neutron numbers 91, 93, 95, and 97 were investigated using the projected shell...     

Techno-economic analysis of new integrated system of humid air turbine,organic Rankine cycle,and parabolic trough collector

Journal of Thermal Analysis and Calorimetry - Microgas turbines are one of the most well-known technologies for distributed generation. Unfortunately, their efficiency is not as high as it should...     

Comparison of the stability of thymine tautomers and the interaction of its tautomers with Na+, K+, Mg2+ and Ca2+ in gas and solvent phases

The present study compared the interactions among Na ⁺, K ⁺, Mg²⁺ and Ca²⁺, thymine and its tautomers in the gas and solvent phase, an interaction dependent upon the electronic construction of the tautomers. Three types of cation interaction with thymine and its tautomers were observed. In the first one, the metal cations interacted with a lone pair of nitrogen or oxygen of the tautomers. In the second type, there was an interaction among the cations, nitrogen and oxygen at the same time; the last one was that of cations with the electron density of thymine π-system, where the cations were perpendicular to the ring of thymine. The interaction of metals cation with tautomers was studied in the gas and solvent phases; a comparison was then made between interactions in two phases. The interaction energy for all complexes indicated the stability of complexes, an energy which was higher in Ca²⁺ and Mg²⁺ compared with Na⁺ and K⁺. Concerning K⁺ and Na⁺, the stability of all complexes of tautomers was greater than that of thymine complexes; however, the stability of certain Ca²⁺ and Mg²⁺ complexes was lower than the complexes of thymine.     

Bilayer Cylindrical Conduit Consisting of Electrospun Polycaprolactone Nanofibers and DSC Cross‐Linked Sodium Alginate Hydrogel to Bridge Peripheral Nerve Gaps

Herein, a bilayer cylindrical conduit (P‐CA) is presented consisting of electrospun polycaprolactone (PCL) nanofibers and sodium alginate hydrogel covalently cross‐linked with N,N′‐disuccinimidyl carbonate (DSC). The bilayer P‐CA conduit is developed by combining the electrospinning and outer–inner layer methods. Using DSC, as a covalent crosslinker, increases the degradation time of the sodium alginate hydrogel up to 2 months. The swelling ratio of the hydrogel is also 503% during the first 8 h. The DSC cross‐linked sodium alginate in the inner layer of the conduit promotes the adhesion and proliferation of nerve cells, while the electrospun PCL nanofibers in the outer layer provide maximum tensile strength of the conduit during surgery. P‐CA conduit promotes the migration of Schwann cells along the axon in a rat model based on functional and histological evidences. In conclusion, P‐CA conduit will be a promising construct for repairing sciatic nerves in a rat model.     

An Evolutionary Approach to Optimizing Teleportation Cost in Distributed Quantum Computation

International Journal of Theoretical Physics - Distributed quantum computing has been well-known for many years as a system composed of a number of small-capacity quantum circuits. Limitations in...     

Multicomponent reaction of amine,carbon disulfide,and fluoronitrobenzene via nucleophilic attack on the fluorinated carbon for the synthesis of nitrophenyl methylcarbamodithioates

In this paper, multicomponent reaction of amine, carbon disulfide and fluoronitrobenzene is reported for the synthesis of nitrophenyl methylcarbamodithioate derivatives. The method is based on the nucleophilic attack of the activated methylcarbamodithioate salt to fluoronitrobenzene. Several starting materials are tested and successfully produced the corresponding nitrophenyl methylcarbamodithioate. A possible mechanism for the reaction is suggested.