Synthesis and thermal stability of ZnO nanowires

ZnO nanowires (NWs) were synthesized on Au-coated Si (100) substrates by vapor transport method. The effect of high temperature annealing on the structural and chemical composition as well as thermal stability was studied. The as-prepared ZnO NWs was nearly stoichiometric and identified as hexagonal ZnO phase. After annealing at 1,473 K, the atomic ratio of O/Zn, the intensity of the diffraction peaks, and the diameter of nanowires were increased. The ZnO NWs were fragmented into nanocrystals and the fragments coalesced with each other after annealing at 1,673 K. The thermal stability of ZnO NWs was studied by thermo-gravimetric (TG) analysis. A sharp increase in the TG curves was observed and can be attributed to the oxidation of some possibly presented Zn atoms. The activation energy of oxidation of Zn interstitial atoms was found to be 484.81 kJ mol^?1. A mass gain peak was observed after annealing at 1,473 K, but it was completely eliminated after annealing at 1,673 K.     

5-Aryl-1-Arylideneamino-1H-Imidazole-2(3H)-Thiones: Synthesis and In Vitro Anticancer Evaluation

A novel series of N-1 arylidene amino imidazole-2-thiones were synthesized, identified using IR, ¹H-NMR, and ¹³C-NMR spectral data. Cytotoxic effect of the prepared compounds was carried out utilizing three cancer cell lines; MCF-7 breast cancer, HepG2 liver cancer, and HCT-116 colon cancer cell lines. Imidazole derivative 5 was the most potent of all against three cell lines. DNA flow cytometric analysis showed that, imidazoles 4d and 5 exhibit pre-G1 apoptosis and cell cycle arrest at G2/M phase. The results of the VEGFR-2 and B-Raf kinase inhibition assay revealed that compounds 4d and 5 displayed good inhibitory activity compared with reference drug erlotinib.     

Quantumness Measures for a System of Two Qubits Interacting with a Field in the Presence of the Time-Dependent Interaction and Kerr Medium

In this work, we introduce the standard Tavis-Cummings model to describe two-qubit system interacting with a single-mode field associated to power-law (PL) potentials. We explore the effect of the time-dependent interaction and the Kerr-like medium. We solve the Schrödinger equation to obtain the density operator that allows us to investigate the dynamical behaviour of some quantumness measures, such as von Neumann entropy, negativity and Mandel’s parameter. We provide how these entanglement measures depend on the system parameters, which paves the way towards better control of entanglement generation in two-qubit systems. We find that the enhancement and preservation of the atoms-field entanglement and atom-atom entanglement can be achieved by a proper choice of the initial parameters of the field in the absence and presence of the time-dependent interaction and Kerr medium. We examine the photons distribution of the field and determine the situations for which the field exhibits super-poissonian, poissonian or sub-poissonian distribution.     

Magnetic,Electronic, and Optical Studies of Gd-Doped WO3: A First Principle Study

Tungsten trioxide (WO₃) is mainly studied as an electrochromic material and received attention due to N-type oxide-based semiconductors. The magnetic, structural, and optical behavior of pristine WO₃ and gadolinium (Gd)-doped WO₃ are being investigated using density functional theory. For exchange-correlation potential energy, generalized gradient approximation (GGA+U) is used in our calculations, where U is the Hubbard potential. The estimated bandgap of pure WO₃ is 2.5 eV. After the doping of Gd, some states cross the Fermi level, and WO₃ acts as a degenerate semiconductor with a 2 eV bandgap. Spin-polarized calculations show that the system is antiferromagnetic in its ground state. The WO₃ material is a semiconductor, as there is a bandgap of 2.5 eV between the valence and conduction bands. The Gd-doped WO₃’s band structure shows few states across the Fermi level, which means that the material is metal or semimetal. After the doping of Gd, WO₃ becomes the degenerate semiconductor with a bandgap of 2 eV. The energy difference between ferromagnetic (FM) and antiferromagnetic (AFM) configurations is negative, so the Gd-doped WO₃ system is AFM. The pure WO₃ is nonmagnetic, where the magnetic moment in the system after doping Gd is 9.5599575 μB.     

Synthesis,reactions, and biological study of some new thienopyrimidine derivatives as antimicrobial and anti‐inflammatory agents

Pyrimidine and thienopyrimidine derivatives play a very important role in organic chemistry because of their wide applications as bioactive compounds with multiple biological activities. However, a literature survey revealed that the merger of different groups in the thieno[2,3‐d]pyrimidine heterocyclic ring enhances its antibacterial, antifungal and anti‐inflammatory activities. This encouraged us to prepare a new series of thieno[2,3‐d]pyrimidine heterocyclic compounds and to test them as antimicrobial and anti‐inflammatory agents. These compounds have shown remarkable activity toward fungi, bacteria, and inflammation. Thus, these compounds have been prepared by the chloroacylation of 5‐amino‐4‐phenyl‐2‐(p‐tolylamino)thieno[2,3‐d] pyrimidine‐6‐carboxamide ( 4 ) using chloroacetyl chloride under neat condition to afford the target compound ( 6 ), which was used as precursor for the synthesis of a number of bioactive compounds. Thus reaction of the chloromethylpyrimidine derivative ( 6 ) with triphenylphosphine in dry benzene gave the corresponding ((4‐oxo‐9‐phenyl‐7‐(p‐tolylamino)‐3,4‐dihydropyrimido[4′,5′:4,5]thieno[2,3‐d]pyrimidin‐2‐yl)methyl) triphenylphosphonium chloride ( 7 ). Compounds 8a – 8c and 9a – 9c were obtained by the reaction of 7 with some selected aromatic aldehydes and ketones in methanol and sodium methoxide under Wittig reaction condition. The structures of the all new synthesized compounds were established on the basis of their analytical and spectral data (IR, ¹H NMR, ¹³C NMR, and MS).     

In Silico Exploration of Potential Natural Inhibitors against SARS-Cov-2 nsp10

In continuation of our previous effort, different in silico selection methods were applied to 310 naturally isolated metabolites that exhibited antiviral potentialities before. The applied selection methods aimed to pick the most relevant inhibitor of SARS-CoV-2 nsp10. At first, a structural similarity study against the co-crystallized ligand, S-Adenosyl Methionine (SAM), of SARS-CoV-2 nonstructural protein (nsp10) (PDB ID: 6W4H) was carried out. The similarity analysis culled 30 candidates. Secondly, a fingerprint study against SAM preferred compounds 44, 48, 85, 102, 105, 182, 220, 221, 282, 284, 285, 301, and 302. The docking studies picked 48, 182, 220, 221, and 284. While the ADMET analysis expected the likeness of the five candidates to be drugs, the toxicity study preferred compounds 48 and 182. Finally, a density-functional theory (DFT) study suggested vidarabine (182) to be the most relevant SARS-Cov-2 nsp10 inhibitor.     

Methoxyperylene bisimides and perylene lactame imides: novel, red fluorescent dyes

The synthesis of methoxyperylene bisimides and perylene lactame imides with aliphatic N-substituents is described. Both classes of dyes exhibit fluorescence in the bathochromic region of visible light so that red light is obtained. The lightfastness of the dyes is very high, thus, there is special interest for diverse applications.     

Molecularly Imprinted Electrochemical Sensor for the Detection of Organophosphorus Pesticide Profenofos

The presence of profenofos (PFF) in food has been strictly limited by legislation due to its genotoxic and toxic effects on health. It is therefore very important to establish simple and rapid analytical methods to detect traces of this insecticide. A reusable molecularly imprinted polypyrrole MIP(O-PPy) on a glassy carbon electrode (GCE) has been developed to measure PFF. The PPy was polymerized by cyclic voltammetry (CV) in the presence of template molecules (PFF) in an acidic solution on a GCE. The various experimental parameters such as film thickness, analyte/monomer ratio, and removal/rebinding requirements were examined and optimized. The signal of the redox probe (ferrocyanide/ferrocyanide) was used for the electrochemical detections. All steps of the sensor manufacturing, removal/rebinding of template molecules, and response to different PFF concentrations were tested by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The MIP sensor was able to detect PFF in the linear ranges of 1.0×10⁻⁹ to 1.0×10⁻⁶ M and 1.0×10⁻⁹ to 5.0×10⁻⁶ M, with detection limits, a signal-to-noise ratio (S/N) of three was used to estimate LOD, of about 1 nM using DPV and EIS, respectively. The MIP (PPy) GCE provided excellent PFF recognition performance and was successfully used to quantify PFF in sweet pepper samples, yielding recoveries not greater than 108 %.     

Preconcentration and determination of ceftazidime in real samples using dispersive liquid–liquid microextraction and high‐performance liquid chromatography with the aid of experimental design

A rapid and simple method for the extraction and preconcentration of ceftazidime in aqueous samples has been developed using dispersive liquid–liquid microextraction followed by high‐performance liquid chromatography analysis. The extraction parameters, such as the volume of extraction solvent and disperser solvent, salt effect, sample volume, centrifuge rate, centrifuge time, extraction time, and temperature in the dispersive liquid–liquid microextraction process, were studied and optimized with the experimental design methods. Firstly, for the preliminary screening of the parameters the taguchi design was used and then, the fractional factorial design was used for significant factors optimization. At the optimum conditions, the calibration curves for ceftazidime indicated good linearity over the range of 0.001–10 μg/mL with correlation coefficients higher than the 0.98, and the limits of detection were 0.13 and 0.17 ng/mL, for water and urine samples, respectively. The proposed method successfully employed to determine ceftazidime in water and urine samples and good agreement between the experimental data and predictive values has been achieved.     

New dimeric Schiff base quinoline complexes: Synthesis,spectral characterization,electrochemistry and cytotoxicity

A novel Schiff base ligand (H‐DPPMHQ) derived from 2‐hydrazineylquinoline and 1,3‐diphenyl‐1H‐pyrazole‐5‐carbaldehyde and its dimeric complexes with compositions [Cr(DPPMHQ)Cl]₂?2Cl and [M(DPPMHQ)Cl]₂ (where M = Cu(II), Co(II), Ni(II) and Zn(II)) have been synthesized and characterized using physicochemical methods like elemental analysis, magnetic susceptibility and molar conductivity measurements, multispectral techniques and electrochemical studies. The molar conductance data reveal that all metal chelates are non‐electrolytes, except the Cr(III) complex which shows a Λ_M value of 146.82 Ω^?1 cm² mol^?1, indicating that it is a 1:2 electrolyte. Infrared spectral results show that the metal is organized through four nitrogen atoms (azomethine and deprotonated imine groups, pyrazole and quinoline rings) besides chlorine atoms. The NH proton is also displaced during complexation, as indicated by ¹H NMR spectral data. Based on the electron spin resonance and ligand field parameter data, the bonding parameters of these complexes have been calculated. Using Coats–Redfern and Horowitz–Metzger equations, thermodynamic parameters were determined. The spectral data indicate that the dimeric complexes have octahedral geometry around the central metal ions. The cytotoxic activities of all compounds were evaluated towards human breast cancer (MCF‐7) and lung cancer (A549) cell lines.