Acrylic‐Acid‐Functionalized PolyHIPE Scaffolds for Use in 3D Cell Culture

This study describes the development of a functional porous polymer for use as a scaffold to support 3D hepatocyte culture. A high internal phase emulsion (HIPE) is prepared containing the monomers styrene (STY), divinylbenzene (DVB), and 2‐ethylhexyl acrylate (EHA) in the external oil phase and the monomer acrylic acid (Aa) in the internal aqueous phase. Upon thermal polymerization with azobisisobutyronitrile (AIBN), the resulting porous polymer (polyHIPE) is found to have an open‐cell morphology and a porosity of 89%, both suitable characteristics for 3D cell scaffold applications. X‐ray photo­electron spectroscopy reveals that the polyHIPE surface contained 7.5% carboxylic acid functionality, providing a useful substrate for subsequent surface modifications and bio‐conjugations. Initial bio‐compatibility assessments with human hepatocytes show that the acid functionality does not have any detrimental effect on cell adhesion. It is therefore believed that this material can be a useful precursor scaffold towards 3D substrates that offer tailored surface functionality for enhanced cell adhesion.

     

Garlic Powder as a Safe Environment Green Corrosion Inhibitor for Mild Steel in Acidic Media; Adsorption and Quantum Chemical Studies

The corrosion inhibition of mild steel in H3PO4 solution by garlic powder was investigated using weight loss and polarization techniques. The adsorption of garlic powder was found to obey Langmuir adsorption isotherm. Maximum inhibition efficiency was 75% at 50 °C and 250 ppm inhibitor concentration. The values of heat of adsorption were negative indicating the spontaneous adsorption process. Quantum chemical calculations were used successfully to evaluate the theoretical inhibitor efficiency. Mathematical and statistical analyses were also used to represent the corrosion rate data with high correlation coefficients. Polarization measurements showed that garlic powder was a mixed — type inhibitor.     

Magnesium oxide microspheres as a novel solid‐phase extraction sorbent for the determination of benzo[a]pyrene in environmental water samples

Magnesium oxide microspheres were developed as a novel SPE sorbent for the determination of benzo[a]pyrene (BaP), one of the most potent carcinogenic agents, in environmental water samples. The parameters controlling the extraction efficiency, such as elution volume, flow rate, pH values, and breakthrough volume, were investigated in detail. Considering the facile preparation and satisfying recovery, a corresponding analytical method has been developed to determine the concentration of BaP in real tap water, river water, and seawater. The recoveries for the spiked BaP were excellent (94–101%).     

Scanning Electrochemical Cell Microscopy Investigation of Single ZIF‐Derived Nanocomposite Particles as Electrocatalysts for Oxygen Evolution in Alkaline Media

“Single entity” measurements are central for an improved understanding of the function of nanoparticle‐based electrocatalysts without interference arising from mass transfer limitations and local changes of educt concentration or the pH value. We report a scanning electrochemical cell microscopy (SECCM) investigation of zeolitic imidazolate framework (ZIF‐67)‐derived Co?N‐doped C composite particles with respect to the oxygen evolution reaction (OER). Surmounting the surface wetting issues as well as the potential drift through the use of a non‐interfering Os complex as free‐diffusing internal redox potential standard, SECCM could be successfully applied in alkaline media. SECCM mapping reveals activity differences relative to the number of particles in the wetted area of the droplet landing zone. The turnover frequency (TOF) is 0.25 to 1.5 s^?1 at potentials between 1.7 and 1.8 V vs. RHE, respectively, based on the number of Co atoms in each particle. Consistent values at locations with varying number of particles demonstrates OER performance devoid of macroscopic film effects.     

Heteropolyacid as a New,Green and Recyclable Catalyst for the Synthesis of 2‐Aryl Benzoxazole under Solvent‐Free Conditions

A simple, convenient and general method has been developed for the synthesis of 2‐arylbenzoxazole via condensation of o‐aminophenols and benzoyl chloride derivatives under solvent‐free conditions in the presence of a catalytic amount of heteropolyacids in good yields.     

The Direct Electron Transfer of Iron‐containing Metal Organic Frameworks (Mil‐100) and Its Catalysis for the Oxygen Reduction Reaction in Room‐Temperature Alkaline Media on a Glass Carbon Electrode

The most common electrocatalysts for the oxygen reduction reaction (ORR) are platinum‐based ones. This work demonstrates the performance of iron‐containing metal organic frameworks (MOFs) as non‐platinum‐based nano‐electrocatalysts for ORR in an alkaline medium. As a new non‐platinum catalyst to achieve the active sites for the ORR, Mil‐100 (Fe) nanoparticles were used in aqueous KOH by the rotating‐disk electrode method. The main objectives of this study are the investigations on the electron transfer number (n ), Tafel slope, and catalytic performance. The particles size of the obtained powders is in the nanoscale range (approximately 25 nm). The electron transfer number for the ORR on the surface of iron‐containing catalyst is approximately 4, and the Tafel slope of diffusion‐corrected kinetic current density is ~50.7 mV per decade at low overpotential. This work might extend a new non‐precious‐metal catalyst structure for ORR for use in low‐temperature fuel cells.     

Montmorillonite as a Heterogeneous Catalyst in the Efficient,Mild and One Pot Synthesis of Schiff Bases under Solvent‐Free Conditions

A mild and efficient method has been reported for preparation of Schiff base ligands through condensation reaction of various aromatic aldehydes and ketones with different aromatic amines in the presence of montmorillonite as a heterogeneous catalyst under solvent free conditions. The advantages of this friendly, economically, environmentally and mild method are such as; simplicity of the reaction procedure, reusability of catalyst, simple work‐up, high product yields and very short reaction times.     

A Green Approach for the One‐Pot,Three‐Component Synthesis of 2‐Arylpyrroloacridin‐1(2H)‐Ones using Lactic Acid as a Bio‐based Catalyst under Solvent‐Free Conditions

A facile and benign synthetic strategy is proposed for the synthesis of 2‐arylpyrroloacridin‐1(2H )‐ones via a lactic acid‐catalyzed three‐component reaction of dimedone, various anilines, and isatins under solvent‐free conditions. Avoidance of hazardous organic solvents, the use of a one‐pot multicomponent procedure for the synthesis of 2‐arylpyrroloacridin‐1(2H )‐ones, operational simplicity, no need for column chromatography, lactic acid utilization as a bio‐based organic compound, reusability, homogeneity, and commercial availability of the catalyst, and superior synthetic performance are some important aspects of this methodology to access a series of pyrroloacridine motifs with potentially biological scaffolds.     

Application of Nanosized Cu0.5Co0.5Fe2O4 Spinel Ferrite as a Nanocatalyst in the Synthesis of 14‐Aryl‐14H‐dibenzo[a,j]xanthene Derivatives under Solvent‐free Conditions

Copper and cobalt substituted spinel ferrites Cu_1‐xCo_xFe₂O₄ (0≤X≤1) have been synthesized by using hydrothermal method. The resultant spinel ferrites were systematically characterized by different techniques such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FT‐IR). It was indicated that all the resultant spinel ferrites obtained by the hydrothermal method had the single‐phase crystalline. The resultant spinel ferrites were employed in the synthesis of 14‐aryl‐14‐H‐dibenzo[a,j]xanthene derivatives. It was found that the nanocatalyst Cu_0.5Co_0.5Fe₂O₄ displays the best performance in the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes. The catalyst was reused several times without significant loss of its activity for the preparation of desired product. In addition high yields of the products, solvent‐free conditions and reusability of the catalyst are other worthwhile advantages of the present study.     

Facile and Mild Synthesis and Characterization of Some New Diazo Dyes on the Basis of Schiff Bases in the Presence of Nanocrystalline Magnesium Oxide as a Base Catalyst under Solvent‐free Conditions

In this research, some new diazo dyes including Schiff base have been synthesized by the condensation reaction between ethylenediamine and derivatives of salicylaldehyde containing diazo functional groups in the presence of nanocrystalline magnesium oxide as a solid base catalyst under solvent‐free conditions. Nanocrystalline magnesium oxide has been characterized by XRD, BJH and TEM techniques. The corresponding products have been obtained in excellent yields and high purity. All of the obtained diazo‐Schiff bases are highly colored and can be applicable as useful diazo dyes and characterized by spectroscopy data.