Toward higher extraction and enrichment factors via a double‐reservoirs microfluidic device as a micro‐extractive platform

In this study, firstly, a double‐reservoir and switchable prototype of a micro‐chip along with the respective holders were fabricated. A cyclic desorption process using microliter volume of organic solvent was adopted to prevent any outdoor contamination. As extractive phases, two identical sheets of electrospun polyamide/polypyrrole/titania nanofibers were synthesized using core–shell electro‐spinning technique and utilized for determination of memantine in plasma samples. Field emission scanning electron microscopy images showed a high degree of porosity and homogeneity throughout the sheet structure. Also, energy dispersive X‐ray analysis confirmed the presence of titania, while the recorded Fourier transform infrared spectra proved the chemical structures of the polymeric mats. The incorporation of titania as well as polypyrrole in the composition of polyamide nanofibers improved both mechanical stability and extraction capacity of the extractive phase and therefore facilitated the extraction/desorption process. The limits of detection and quantification were 0.01 and 0.04 ng/mL, respectively. In addition, the interday and intraday precisions were lower than 6.7% (n = 3). The linearity was in the range of 0.14–75.00 ng/mL, while recoveries were between 94.1 and 98.4% with the regression coefficient of 0.9987.     

Nanoparticle using parallel split rings and implementation of chain for creating Fano resonance with polarization independence for energy harvesting in mid-infrared

In optical devices, the polarization of the incident wave affects the Nano particle characteristics. Therefore, designing a polarization-independent device is significant in the process of designing optical structures. On the other hand, the concept of Fano resonance and dark mode has been utilized for achieving more energy enhancement. In this paper, we have developed a symmetrical Nano antenna by employing Fano resonance, which is independent of the incident wave polarization. The proposed Nano antenna is modified in mid infrared regime for biosensing and energy harvesting applications. The designed metamaterial antenna is made by Nano split ring resonators with etched capacitive gaps, which are utilized for concentrating energy. The introduced Nano antenna has a bright and dark mode with a weak enhancement of electric field. The effect of the incident wave polarization is investigated at wave incident angles between 0° and 45° to illustrate the independency of the polarization due to the symmetrical shape of the Nano antenna. In order to trigger the dark mode and enhance the electric field, a Nano chain is incorporated in the final structure. This arrangement has led to increasing of electric field drastically. Furthermore, the figure of merit has been calculated as an advantageous factor in sensing the surrounding materials with various refractive indices. Our findings illustrated that the chain arrangement has caused a peak in the linear form of the extinction cross section of the Nano antenna. This in turn has resulted in the appearance of Fano resonance with no impact on the resonance frequency that has been originally adjusted by capacitive gaps and inductive strips.     

Anharmonic 1D actuator model including electrostatic and Casimir forces with fractional damping perturbed by an external force

We modeled a one-dimensional actuator including the Casimir and electrostatic forces perturbed by an external force with fractional damping. The movable electrode was assumed to oscillate by an anharmonic elastic force originated from Murrell–Mottram or Lippincott potential. The nonlinear equations have been solved via the Adomian decomposition method. The behavior of the displacement of the electrode from equilibrium position, its velocity and acceleration were described versus time. Also, the changes of the displacement have been investigated according to the frequency of the external force and the voltage of the electrostatic force. The convergence of the Adomian method and the effect of the orders of expansion on the displacement versus time, frequency, and voltage were discussed. The pull-in parameter was obtained and compared with the other models in the literature. This parameter was described versus the equilibrium position and anharmonicity constant.     

Dominant Majorana bound energy and critical current enhancement in ferromagnetic-superconducting topological insulator

Among the potential applications of topological insulators, we theoretically study the coexistence of proximity-induced ferromagnetic and superconducting orders in the surface states of a 3-dimensional topological insulator. The superconducting electron-hole excitations can be significantly affected by the magnetic order induced by a ferromagnet. In one hand, the surface state of the topological insulator, protected by the time-reversal symmetry, creates a spin-triplet and, on the other hand, magnetic order causes to renormalize the effective superconducting gap. We find Majorana mode energy along the ferromagnet/superconductor interface to sensitively depend on the magnitude of magnetization m _zfs from superconductor region, and its slope around perpendicular incidence is steep with very low dependency on m _zfs . The superconducting effective gap is renormalized by a factor η(m _zfs ), and Andreev bound state in ferromagnet-superconductor/ferromagnet/ferromagnet-superconductor (FS/F/FS) Josephson junction is more sensitive to the magnitude of magnetizations of FS and F regions. In particular, we show that the presence of m _zfs has a noticeable impact on the gap opening in Andreev bound state, which occurs in finite angle of incidence. This directly results in zero-energy Andreev state being dominant. By introducing the proper form of corresponding Dirac spinors for FS electron-hole states, we find that via the inclusion of m _zfs , the Josephson supercurrent is enhanced and exhibits almost abrupt crossover curve, featuring the dominant zero-energy Majorana bound states.     

Naphthoflavone propargyl ether inhibitors of cytochrome P450

Cytochrome P450 enzymes protect the body from foreign substances through a mechanism that involves oxidation of those substances into more readily excretable polar compounds. It has been shown that some naphthoflavones function as substrates of certain P450 enzymes (CYP1A1 and CYP1B1) and with appropriate structural changes may become inhibitors. Moreover, propargyl ether derivatives of adamantane have been shown to function as selective inactivators of some P450 enzymes (CYP2B1 and CYP2B5). In an attempt to improve the potency and selectivity of inhibition, we have designed and synthesized a series of naphthoflavone propargyl ethers. We report here the synthesis, X-ray crystal structures, and inhibition data (IC₅₀ of EROD inhibition in CYP1A1 and CYP1B1 enzymes) of α-naphthoflavone 2′-propargyl ether, β-naphthoflavone 2′-propargyl ether, α-naphthoflavone 4′-propargyl ether, and β-naphthoflavone 4′-propargyl ether. Crystallographic data: α-naphthoflavone 2′-propargyl ether, , a=7.775(1) ?, b=8.062(1) ?, c=13.110(1) ?, α=84.32(1)°, β=75.42(1)°, γ=86.56(1)°, V=790.8(2) ?³; β-naphthoflavone 2′-propargyl ether, , a=7.605(2) ?, b=7.793(1) ?, c=14.167(2) ?, α=77.06(1)°, β=75.41(1)°, γ=89.54(1)°, V=790.9(2) ?³; α-naphthoflavone 4′-propargyl ether, P21/n, a=14.595(2) ?, b=4.708(1) ?, c=24.745(6) ?, β=106.31(2)°, V=1631.8(7) ?³; β-naphthoflavone 4′-propargyl ether, P1, a=4.8871(5) ?, b= 7.9597(7) ?, c=21.788(3) ?, α=81.771(9)°, β=89.918(10)°, γ=72.223(8)°, V= 797.9(2) ?³.     

A convenient route toward one‐pot multicomponent synthesis of spirochromenes and pyranopyrazoles accelerated via quinolinic acid

In the present work, the catalytic activity of quinolinic acid (QUIN) was studied for the synthesis of spirochromene and pyranopyrazole derivatives from readily available materials. The salient features of these one‐pot multicomponent protocols are the clean reaction profile, easy isolation of products, no chromatographic separation techniques, high efficiency, short reaction time, and high yield of products plus using QUIN as a new, inexpensive, commercially available, and efficient organocatalyst.     

Construction of molecularly imprinted nanoparticles by employing ultrasound waves for selective determination of doxepin from human plasma samples: Modeling and optimization

In this work, molecularly imprinted nanoparticles (MINPs) were applied as selective adsorbent for ultrasound‐assisted micro‐solid‐phase extraction (UAMSPE) of doxepin (DP) from human plasma samples, which was then cleaned up, pre‐concentrated and subjected to HPLC. The MINPs were synthesized based on a non‐covalent approach by precipitation polymerization utilizing methacrylic acid and styrene as functional monomers, DP as template, ethylene glycol dimethacrylate as cross‐linker and 2,2‐azobisisobutyronitrile (AIBN) as initiator. The obtained MINPs were characterized by Fourier transform‐infrared and field emission scanning electron microscopy. Factors influencing the efficiency of UAMSPE such as sonication time, volume of eluent solvent and amount of sorbent were investigated using a central composite design and the optimal points were identified as 4 min of sonication time, 380 μL of eluent solvent and 30 mg of sorbent. Under optimized conditions, the proposed method has linear responses in the range of 0.2–2000 ng mL^–1, with a satisfactory limit of detection of 0.04 ng mL^–1 and limit of quantification of 0.11 ng mL^–1.     

Synthesis of four series of quinoline‐based heterocycles by reacting 2‐chloroquinoline‐3‐carbonitriles with various types of isocyanides

Four distinct sets of functionalized quinolines were synthesized by reacting 2‐chloroquinoline‐3‐carbonitriles with various types of isocyanides under appropriate conditions. The palladium‐catalysed reaction of less hindered aliphatic and aromatic isocyanides with 2‐chloroquinoline‐3‐carbonitriles yielded 2‐alkyl(aryl)‐1‐imino‐1H‐pyrrolo[3,4‐b]quinolin‐3(2H)‐one derivatives; however, the catalysed reaction of more hindered isocyanides such as tert‐butyl isocyanide produced the corresponding 3‐cyanoquinoline‐2‐carboxamides. Interestingly, chloroquinoline‐3‐carbonitriles reacted with ethyl isocyanoacetate in the presence of Cs₂CO₃ to generate imidazo[1,5‐a]quinoline derivatives; notably, tosylmethyl isocyanide under the same conditions formed unprecedented 2‐tosyl‐3‐cyanoquinolines.     

Bis‐aroylhydrazone based on 2,2′‐bis substituted diphenylamine for synthesis of new binuclear organotin (IV) complexes: Spectroscopic characterization,crystal structures,in vitro DNA‐binding,plasmid DNA cleavage,PCR and cytotoxicity against MCF7 cell line

New dinuclear organotin (IV) complexes, Me₄Sn₂L, Ph₄Sn₂L and Bu₄Sn₂L, have been synthesized from reaction of R₂SnCl₂ (R = Me, Ph and Bu) with a 2,2′‐bis‐substituted diphenylamine arοylidene hydrazone, H₄L. The synthesized compounds were investigated by elemental analysis and infrared, ¹H‐NMR and ¹¹⁹Sn‐NMR spectroscopy. The structures of H₄L, Me₄Sn₂L and Bu₄Sn₂L were also confirmed by X‐ray crystallography. H₄L molecules adopt (E)‐configuration and keto‐tautomeric form in the solid state. In all complexes, the bis‐hydrazone acts as a tetra‐anionic ligand with two contiguous ONO tridentate domains that coordinate the two R₂Sn moieties in the enolate form. The coordination environments of both tin centers are five‐coordinate. DNA‐binding studies were performed by UV–Vis spectroscopy, and the results indicate that the synthesized compounds significantly interact with calf thymus‐DNA in the intercalative mode. The results of polymerase chain reaction assay show that all the compounds affect on amplification of DNA, and complexes are more effective than ligands. The in vitro cytotoxicity against the human breast cancer line (MCF7) was determined using the MTT assay, and H₄L and the dibutytin complex showed higher activity.     

Hydrogen-abstraction reactions of fully hydrogenated silicon fullerene cages with the amino radical: a density functional study

Structural Chemistry - We applied density functional theory calculations to study reactions NH2 ?+ SinHn fullerenes (n?=?4, 6, 8, 10, 20, 24, 30, 36, and 50). The reactions...