Solvent-free synthesis of new spiropyrroloindole compounds using Fe3O4/TiO2/MWCNTs MNCs via multicomponent reactions: assessment of new spiropyrroloindole antioxidant activity

In this study, water extract of Spinacia oleracea leaves was used for the synthesis of Fe₃O₄/TiO₂/MWCNTs magnetic nanocomposites and high performance of this catalyst was confirmed by employing it in the solvent-free multicomponent reactions of anilines, oxalyl chloride, diamines or hydroxyamines, electron-deficient acetylenic ester, α-haloketones and Et₃N at room temperature for the generation of new spiropyrroloindoles in high yields. This catalyst could be utilized several times and has a significant role in the yield of product. The synthesized spiropyrroloindoles have NH and OH group in their structure and for this reason have good antioxidant activity. Also, by employing Gram-positive and Gram-negative bacteria and the disk diffusion procedure confirmed the antimicrobial effect of some spiropyrroloindole derivatives. The results showed that synthesized spiropyrroloindoles prevented the bacterial growth. This used process for preparation of new spiropyrroloindoles has some improvements such as low reaction time, product with high yields, and simple separation of catalyst and products.

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Green synthesis of silver nanoparticles from aqueous extract of Ziziphora clinopodioides Lam and evaluation of their bio-activities under in vitro and in vivo conditions

The purpose of this experiment was the green synthesis of silver nanoparticles from aqueous extracts of Ziziphora clinopodioides Lam (AgNPs@Ziziphora) and assessment of their cytotoxicity, antioxidant, antibacterial, antifungal, and cutaneous wound-healing effects. These nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction (XRD), field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDX), atomic force microscopy (AFM), and transmission electron microscopy (TEM). UV–Vis, TEM, and FESEM analyses indicated that the size of Ag nanoparticles (AgNPs) depended on Z. clinopodioides and AgNO₃ concentrations. In vitro biological experiments indicated that AgNPs@Ziziphora has excellent antioxidant potential against DPPH, antifungal effects against Candida guilliermondii, Candida krusei, Candida glabrata, and Candida albicans, and antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Streptococcus pneumonia, Salmonella typhimurium, Pseudomonas aeruginosa, and Escherichia coli O157:H7. Also, these nanoparticles did not exhibit cytotoxicity property against human umbilical vein endothelial cells (HUVECs). An in vivo biological test revealed that AgNPs@Ziziphora ointment significantly (p ≤ 0.01) increased the levels of wound contracture, blood vessels, hydroxyl proline, hexuronic acid, hexosamine, fibrocytes, fibroblasts, and fibrocyte/fibroblast ratio and significantly (p ≤ 0.01) decreased the wound area, and levels of total cells, neutrophils, and lymphocytes than other groups in rats. The results of UV–Vis, XRD, FESEM-EDX, AFM, and TEM confirmed that the aqueous extract of Z. clinopodioides can be used to produce silver nanoparticles with significant antioxidant, antimicrobial, and cutaneous wound-healing properties without any cytotoxicity.     

Durable and highly selective tungsten-substituted MFI metallosilicate catalysts for the methanol-to-propylene process by designing a novel feed-supply technique

For the catalytic reaction of methanol to propylene (MTP), conventional H-ZSM-5 and W-substituted MFI metallosilicate catalysts were successfully synthesized using a hydrothermal method. The catalysts were properly characterized by several techniques. For comparison of the catalytic lifetime, feedstock of MTP was provided by both a conventional system and a novel feed-supply technique. The novel technique used the piezoelectric ultrasonic effect. It was revealed that feed composition via novel feed-supply technique remained totally constant, whereas with conventional system it relatively changed. Complete methanol conversion, higher propylene yield of 54.3%, greater light olefin yield of 85.2%, and longer-term catalytic lifetime of 101 h were productively obtained for H-W(250)AlMFI catalyst using a novel method for provision of feed. The better performance of this catalyst can be attributed to adequate content of tungsten, appropriate mesoporosity, sufficient strength of acidic sites, and stable feed composition of the novel feed-supply technique. Furthermore, the MTP process was miniaturized by the piezoelectric ultrasonic device.     

Silica‐tethered cuprous acetophenone thiosemicarbazone (STCATSC) as a novel hybrid nano‐catalyst for highly efficient synthesis of new 1,2,3‐triazolyl‐based metronidazole hybrid analogues having potent antigiardial activity

The preparation, characterization and application of silica‐tethered cuprous acetophenone thiosemicarbazone (STCATSC) as a novel hybrid nano catalyst for synthesis of new 1,2,3‐triazolyl‐based metronidazole hybrid analogues is described. STCATSC is fully characterized by different microscopic, spectroscopic and physical techniques, including scanning electron microscopy (SEM), transmission, X‐ray diffraction (XRD), Energy‐dispersive X‐ray spectroscopy (EDS), thermogravimetric analysis (TGA), FT‐IR and inductively coupled plasma (ICP) analysis. This catalyst is used to prepare the new 1,2,3‐triazolyl‐based metronidazole hybrid analogues. The ‘Click’ Huisgen cycloaddition reaction of 2‐methyl‐5‐nitro‐1‐prop‐2‐ynyl‐1H‐imidazole with diverse β‐azidoalcohols in a THF‐water media at R.T. provides the products in good to excellent yields using STCATSC. STCATSC is proved to be a stable, low cost, reusable and environmentally benign hybrid catalyst. Products are in vitro tested against Giardia lamblia (G. lamblia) in which determined that all compounds exhibit varied promising antigiardial activity compare to metronidazole as a reference drug. Among the products, 1‐(4‐((2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐phenethoxypropan‐2‐ol and 1‐(4‐((2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐(3‐phenylpropoxy)propan‐2‐ol are demonstrated to exhibit the potent antigiardial activity even stronger than metronidazole.     

Synthesis of spiro[pyrazoloquinoline-oxindoles] and spiro[chromenopyrazolo-oxindoles] promoted by guanidine-functionalized magnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles

Magnetic nanoparticles (MNPs) Fe₃O₄-immobilized guanidine (Fe₃O₄ MNPs-guanidine) have been used as an efficient catalyst for the preparation of spiro[pyrazoloquinoline-oxindoles] and spiro[chromenopyrazolo-oxindoles] by four-component reactions of phenylhydrazine or hydrazine hydrate, isatins, ketoesters and naphthylamine or 2-naphthol under reflux condition in ethanol. This method provides several advantages including mild reaction conditions, the applicability to a wide range of substrates, the reusability of the catalyst and low catalyst loading.     

An implicit 2D hydrodynamic numerical model for free surface–subsurface coupled flow problems

A 2‐dimensional hydrodynamic finite volume model has been proposed for simultaneous simulation of free surface and saturated porous media. The governing equations of the former are 2‐dimensional averaged in a unit width of Navier‐Stokes, whereas that of the latter are Darcy law. An efficient, simple, and stable algorithm has been proposed to track the surface elevation in Cartesian coordinate system by which the water elevation in each computational column has been computed along with the other pressure unknowns simultaneously. The surface position has not been considered to remain in a specific layer so the number of cells in each column have been variably adjusted in accordance with the water surface elevation. Performance of the coupled model has been validated against a range of hydrodynamic problems including propagation of linear short wave, seepage test, tidal oscillation in a lagoon system, gravity current, and saltwater intrusion. Comparison between numerical results, analytical solutions, and experimental data demonstrates that the model represents well the interacting surface water and ground water flow and solute transport processes.     

Controlled and scalable torsional actuation of twisted nylon 6 fiber

Large‐scale torsional actuation occurs in twisted fibers and yarns as a result of volume change induced electrochemically, thermally, photonically, and other means. A quantitative relationship between torsional actuation (stroke and torque) and volume change is here introduced. The analysis is based on experimental investigation of the effects of fiber diameter and inserted twist on the torsional stroke and torque measured when heating and cooling nylon 6 fibers over the temperature range of 26–62 °C. The results show that the torsional stroke depends only on the amount of twist inserted into the fiber and is independent of fiber diameter. The torque generated is larger in fibers with more inserted twist and with larger diameters. These results are successfully modeled using a single‐helix approximation of the twisted fiber structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1278–1286     

Free volume studies in miscible polymer blend systems

This paper summarises the currently available literature concerned with measurement of free volume in miscible, amorphous polymer blends using positron annihilation lifetime spectroscopy (PALS) which probes excluded volume at the angstrom level. Previously reported data is compared with new data from a range of different blend systems. Miscible blends tend to show a negative deviation of free volume size (and to a lesser degree free volume fraction) on mixing due to the intimacy of packing of the blend component macromolecules. A largely immiscible system is also reported and shows a different behaviour (positive deviation of free volume size) and this is ascribed to additional free volume at the interface.     

Developing Novel Fabrication and Optimisation Strategies on Aggregation-Induced Emission Nanoprobe/Polyvinyl Alcohol Hydrogels for Bio-Applications

The current study describes a new technology, effective for readily preparing a fluorescent (FL) nanoprobe-based on hyperbranched polymer (HB) and aggregation-induced emission (AIE) fluorogen with high brightness to ultimately develop FL hydrogels. We prepared the AIE nanoprobe using a microfluidic platform to mix hyperbranched polymers (HB, generations 2, 3, and 4) with AIE (TPE-2BA) under shear stress and different rotation speeds (0–5 K RPM) and explored the FL properties of the AIE nanoprobe. Our results reveal that the use of HB generation 4 exhibits 30-times higher FL intensity compared to the AIE alone and is significantly brighter and more stable compared to those that are prepared using HB generations 3 and 2. In contrast to traditional methods, which are expensive and time-consuming and involve polymerization and post-functionalization to develop FL hyperbranched molecules, our proposed method offers a one-step method to prepare an AIE-HB nanoprobe with excellent FL characteristics. We employed the nanoprobe to fabricate fluorescent injectable bioadhesive gel and a hydrogel microchip based on polyvinyl alcohol (PVA). The addition of borax (50 mM) to the PVA + AIE nanoprobe results in the development of an injectable bioadhesive fluorescent gel with the ability to control AIEgen release for 300 min. When borax concentration increases two times (100 mM), the adhesion stress is more than two times bigger (7.1 mN/mm²) compared to that of gel alone (3.4 mN/mm²). Excellent dimensional stability and cell viability of the fluorescent microchip, along with its enhanced mechanical properties, proposes its potential applications in mechanobiology and understanding the impact of microstructure in cell studies.