The first electrochemical sensor for determination of mangiferin based on an ionic liquid–graphene nanosheets paste electrode

A novel carbon paste electrode modified with graphene nanosheets and an ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) was fabricated and used for the electrochemical study of mangiferin for the first time. This modified electrode offers a considerable improvement in voltammetric sensitivity toward mangiferin, compared to the bare electrode. Square wave voltammetry (SWV) exhibits a linear dynamic range from 5.0?×?10^?8 to 2.0?×?10^?4 M and a detection limit of 20.0 nM for mangiferin. Finally, the proposed method was successfully applied to the determination of mangiferin in real samples such as serum and urine.     

Ultrasound-assisted coating of silk yarn with sphere-like Mn3O4 nanoparticles

The growth of sphere-like trimanganese tetraoxide (Mn₃O₄) nanoparticles on silk fiber was achieved by sequential dipping in an alternating bath of potassium hydroxide and manganese(II) nitrate under ultrasound irradiation. Some parameters such as the effect of pH, numerous sequential dipping and ultrasonic irradiation on growth of the nanoparticles have been studied. The samples were characterized with powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX).     

Experimental Investigation of Heat Transfer Coefficient from the Impingement of a Slot Jet Using Conjugate Gradient Method with Adjoint Equation

The convective heat transfer coefficients resulting from a slot jet on a plane surface have been estimated by using the real measured temperatures in the plate and inverse method. In this study, the inverse method used the conjugate gradient method with an adjoint equation. Distributions of the local heat transfer coefficient on the impingement surface were determined for various Re and H/Dh. It was found the heat transfer coefficients generally tended to decrease with increasing separation distance and to increase with an increase in Reynolds number. This presented method is able to estimate the variation of the local Nusselt number with time.     

Preparation and Rheological Properties of Functionalized Multiwalled Carbon Nanotube/Waterborne Polyurethane Nanocomposites

Waterborne polyurethane (WBPU) was synthesized by a polyaddition reaction with toluene diisocyanate (TDI), polytetramethylene ether glycol (PTMEG), dimethylol propionic acid (DMPA), and triethylamine (TEA). Aqueous polyurethane dispersions with three different weight fractions, 30, 40, and 50 wt%, were prepared. All the dispersions made with these concentrations showed Newtonian viscosity behavior. Multiwalled carbon nanotubes (CNTs) were functionalized using a mixture of sulfuric and nitric acid at a ratio of 3:1 and added to these dispersions in two different loads of 0.1 and 0.5 wt%. Ultraviolet visible spectrometry (UV/Vis) spectroscopy proved the formation of stable suspensions following ultrasonic agitation. The rheology of these suspensions was characterized using dynamic and steady-state measurements. The higher amount of CNT in the suspension imparted non-Newtonian and complex viscoelastic behavior. This was attributed to a physical network formed due to the presence of the functionalized CNTs. The Cox-Merz rule was not observed for these suspensions.     

Poly(N-bromo-N-ethylbenzene-1,3-disulfonamide) and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide as efficient reagents for synthesis of quinolines

Poly(N-bromo-N-ethylbenzene-1,3-disulfonamide) [PBBS] and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide [TBBDA] were used as efficient reagents for the synthesis of quinolines in excellent yields from 2-aminoaryl ketones and carbonyl compounds under aqueous and solvent-free conditions.     

A one-pot, four-component synthesis of α-carboline derivatives

A one-pot method for the efficient and simple synthesis of novel 1H-indolo[2,3-b]pyrazolo[4,3-e]pyridines via a four-component condensation reaction of indolin-2-one, 3-oxo-3-phenylpropanenitrile, and various hydrazines and aldehydes in the ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) is reported.     

The behavior of 6-p-chlorostyryl-3-thioxo-1,2,4-triazin-5-one toward phenylmagnesium bromide

The action of phenylmagnesium bromide on 6-p-chlorostyryl-3-thioxo-1,2,4-triazin-5-one ( 1 ) was studied whereby a mixture of seven products was obtained. These were separated and characterised, and a reasonable mechanism for their formation is presented and discussed.     

Preparation and characterization of curcumin loaded gold/graphene oxide nanocomposite for potential breast cancer therapy

Research on Chemical Intermediates - Graphene oxide (GO) and gold/graphene oxide (Au/GO) nanocomposites were fabricated through a facile chemical route and their application as excellent...     

Novel organosoluble and thermally stable polyetherimides based on a new dianhydride monomer 2,6-bis-(isobenzofuran-1,3-dione-5-yl)pyridine (BIDP)

A series of organosoluble and thermally stable polyetherimides (PEIs) containing pyridine moieties and flexible ether linkages are synthesized based on a new aromatic dianhydride, 2,6-bis-(isobenzofuran-1,3-dione-5-yl)pyridine (BIDP). The prepared polymers are soluble in common aprotic solvents such as DMF, DMSO, NMP and DMAc at room temperature. Thermal behavior of the PEIs is studied by thermogravimetric analysis/dynamic thermal analysis (TGA-DTA). The inherent viscosities of the PEI solutions are in the range of 0.61–0.70 dL/g (in DMSO with a concentration of 0.25 g/dL at 25±0.5°C). The metal ion uptake capacity of PEI-4 for Co(II) removal from aqueous solutions is shown to be remarkably higher than that of the polyimide (PI) with a similar structure reported earlier.     

Selective synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzimidazoles in water at ambient temperature

A highly selective synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzimidazoles from the reaction of o-phenylenediamines and aromatic aldehydes in the presence of silica sulfuric acid is reported. The reactions were performed in ethanol or water and the catalyst could be reused for several runs.