The Novel Synthesis of Functionalized Indenopyrazolones Using Fe3O4 nanoparticles stabilized on MMT: An Efficient Magnetically Recoverable Heterogeneous Nanocomposite Catalyst

A practical and simple approach for the one‐pot multicomponent synthesis of indenopyrazolones is described via the condensation of ninhydrin (indan‐1,2,3‐trione), phenylhydrazine, and various aldehydes in the presence of MMT@Fe₃O₄ as an environmentally benign core/shell nanocomposite catalyst. The catalyst could be recycled using an external magnet easily and reused several times without remarkable loss of its catalytic activity. Furthermore, avoiding hazardous solvents, reusability of the catalyst, easy work‐up, short reaction times, room temperature, and mild reaction conditions are the advantages of this new eco‐friendly protocol.     

Numerical investigation of non-Fourier natural convection of Newtonian nanofluids

Journal of Thermal Analysis and Calorimetry - In the present study, effects of non-Fourier diffusion on the unsteady natural convection heat transfer are investigated in a cavity filled with...     

Photocatalytic Degradation of Antibiotic Norfloxacin Aqueous Solution by Ce/Bi2WO6: Optimization and Simulation of Process by RSM

Russian Journal of Applied Chemistry - This study evaluated a removal efficiency of NLFX from aqueous solutions using a photocatalytic process. In this study, Bi2WO6 were synthesized by microwave...     

Generalized Brans-Dicke Cosmology in the Presence of Matter and Dark Energy

We study the Generalized Brans-Dicke cosmology in the presence of matter and dark energy. Of particular interest for a constant Brans-Dicke parameter, the de Sitter space has also been investigated.     

A Novel Kinetic Approach for Photocatalytic Degradation of Azo Dye with CdS and Ag/CdS Nanoparticles Fixed on a Cement Bed in a Continuous‐Flow Photoreactor

Azo dyes are one of the synthetic dyes that have been used in many textile industries. Azo dye and their intermediate products are toxic, carcinogenic, and mutagenic to aquatic life. Removal of azo dyes is one of the main challenges before releasing the wastes discharged by textile industries. Photocatalytic degradation of azo dyes by nanoparticles is one of the environment‐friendly methods used for the removal of dyes from textile effluents. Therefore, this study focused on degradation of azo dye, Direct Red 264. Photocatalytic degradation of DR 264 azo dye was investigated using CdS and Ag/CdS nanoparticles immobilized on a cement bed in a continuous‐flow photoreactor under UV‐C exposure. The effect of the parameters of type and mass of catalyst, temperature, flow rate, dye concentration, and light intensity were evaluated for azo dye removal. Under optimal conditions, photocatalytic degradation of DR 264 azo dye using Ag/CdS nanoparticles immobilized on a cement bed in a continuous‐flow photoreactor obtained an efficiency of 99.99%. A developed kinetic model was proposed based on the intrinsic elementary reactions. The proposed model is in a good agreement with the Langmuir–Hinshelwood (L–H) equation. The pseudo–steady‐state approximation has considered for the concentration of hydroxyl radicals associated with the L–H model under certain conditions and explains consistently the dependence of the apparent kinetic parameter, k_obs (the reaction rate constant), and K_R (the adsorption equilibrium constant) with the light intensity. Based on the model, k_obs for Ag/CdS was greater than the CdS nanoparticles.     

Synthesis of Monospiro‐2‐amino‐4H‐pyran Derivatives Catalyzed by Propane‐1‐sulfonic Acid‐Modified Magnetic Hydroxyapatite Nanoparticles

Various monospiro‐2‐amino‐4H‐pyran derivatives have been synthesized in high yields (via three‐component coupling of ninhydrin or different isatins with malononitrile and 1,3‐dicarbonyl compounds) in the presence of catalytic amount of propane‐1‐sulfonic acid‐modified magnetic hydroxyapatite nanoparticles in H₂O. Due to easy magnetic removal of nanocatalyst and applying of H₂O as solvent, this protocol enhanced product purity, and promised economic as well as environmental benefits, exemplifying a waste‐free chemistry. More importantly, the catalyst could be easily recycled for more than five times without loss of activity.     

Acidic Ionic Liquid [(CH2)4SO3HMIM][HSO4]: A Green Media for the Simple and Straightforward Synthesis of 2,4,5-Trisubstituted Imidazoles

2,4,5-Trisubstituted imidazoles have been synthesized in excellent yields (85–95%) in the presence of 5 mol% of [(CH₂)₄SO₃HMIM][HSO₄] as a Brønsted acidic ionic liquid.     

Multivariate investigation of interaction between porphyrin ligands and human telomeric DNA

G-quadruplexes are formed by association of DNA strands containing multiple contiguous guanines. The capability of drugs to induce formation or stabilize G-quadruplexes is an active area of cancer therapy investigation. We evaluated interaction between two cationic tetrapyridinoporphyrazines with Na⁺ and K⁺ forms of human telomeric G-quadruplex DNA by chemometrics method. An antiparallel quadruplex structure was found to be stabilized more greatly by these two isomers in the presence of K⁺ and Na⁺ ions. Equilibrium model of a ligand binding with DNA oligomer has been considered as a process of small molecule adsorption on to a lattice of multiple binding sites. In multivariate analysis methods, it is accounted this assertion that during saturation of the macromolecule by a ligand should expect effect of cooperativity due to changes in DNA conformation or the mutual influence between bound ligands. Such phenomenon cannot be entirely described by the classical stepwise complex formation model. From the results of absorption and circular dichroism measurements, the unique site for the ligand binding is suggested to be the intercalating in guanine tetrad plane quadruplex. We found a 2:1 binding stoichiometry for both ligands and Tel22.