A theoretical study of antioxidant activity of some Schiff bases derived from biologically important phenolic aldehydes and phenylenediamines

Because of their numerous biological as well as industrial importance, the study of Schiff bases is an emerging field for the researchers, in recent time. In this study, we have designed some Schiff bases derived from biologically important precursors. The antioxidant activities of the designed compounds are thoroughly studied theoretically using density functional theory taking various parameters like bond dissociation enthalpy, ionization enthalpy, proton dissociation enthalpy, and electron transfer enthalpy followed by the study of effects of solvent, spin density, and molecular orbital on antioxidant activity of the compounds. The comparison of antioxidant activity of the compounds with that of phenol and their parent aldehydes reveals the superior antioxidant activity of the designed compounds. This study contributes towards the information of an important bridge between bioorganic and computational chemistry.     

On Some Class of n-Normed Generalized Difference Sequences Related to lp-Space

In this paper, we introduce the class of n-normed generalized difference sequences related to lp-space. Some properties of this sequence space like solidness, symmetricity, convergence-free etc. are studied. We obtain some inclusion relations involving this sequence space.     

Black holes coupled to scalar fields in higher-dimensional Kaluza-Klein theory

We derive in this paper an exact spherically symmetric solution coupled to scalar fields inn-dimensional Kaluza-Klein theory. A seven-dimensional solution is shown as a special case of the general solution. The solution has two even horizons. The inner horizon corresponds to the Schwarzschild black hole and the outer horizon is due to the scalar fields.     

Adsorption–Desorption of Surfactant for Enhanced Oil Recovery

Surfactant loss due to adsorption on the porous medium of an oil reservoir is a major concern in enhanced oil recovery. Surfactant loss due to adsorption on the reservoir rock weakens the effectiveness of the injected surfactant in reducing oil–water interfacial tension (IFT) and making the process uneconomical. In this study, surfactant concentrations in the effluent of the corefloods and oil–water IFT were determined under different injection strategies. It was found that in an extended waterflood following a surfactant slug injection, surfactant desorbed in the water phase. This desorbed surfactant lasted for a long period of the waterflood. The concentration of the desorbed surfactant in the extended waterflood was very low but still an ultralow IFT was obtained by using a suitable alkali. Coreflood results show an additional recovery of 13.3% of the initial oil in place was obtained by the desorbed surfactant and alkali. Results indicate that by utilizing the desorbed surfactant during the extended waterflood operation the efficiency and economics of the surfactant flood can be improved significantly.     

Higher-dimensional Florides-like solution with cosmological constant

N-dimensional generalization of Florides' interior solution with cosmological constant and Kotller's exterior solution are presented here. The case of uniform density configuration is also considered. One can get back the solutions in four-dimensional space-time by puttingN=4 in the solutions presented here.     

Anisotropic cosmology with extra dimensions

We present an exact solution of the n-dimensional (n > 4) vacuum Einstein field equations with a Bianchi type I metric. The solution may be interpreted as a four-dimensional anisotropic cosmological model. The extra dimensions are related to the energy density and pressures in the model. The physics of the results is discussed at the end of the paper.     

Endocrine disruption: molecular interactions of chlorpyrifos and its degradation products with estrogen receptor

Structural Chemistry - Chlorpyrifos is an extensively used organophosphate pesticide showing broad-spectrum effectiveness on various target pests. Long-term sublethal exposure to this pesticide is...     

Carbonyl oxide chemistry in water cluster: An extended computational study

An extended computational approach has been utilized to explore the reactions of acids with carbonyl oxide, also known as Criegee intermediate (CI). The reactions were explored inside a water cluster containing 50 water molecules. All possibilities of product formation were considered. Among the considered acids, the rate of 1,4-insertion follows the order HCOO < HCl < HNO₃. The most stable products of the reactions between the considered acids and CI have been identified.     

Spin-Probe ESR Studies on Nanocomposite Polymer Electrolytes

The possibility of using spin-probe electron spin resonance (ESR) as a tool to study glass transition temperature, T _g, of polymer electrolytes is explored in 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL)-doped composite polymer electrolyte (PEG)₄₆LiClO₄ dispersed with nanoparticles of hydrotalcite. The T _g is estimated from the measured values of T _50G, the temperature at which the extrema separation 2A _zz of the broad powder spectrum decreases to 50 G. In another method, the correlation time τ_c for the spin probe dynamics was determined by computer simulation of the ESR spectra and T _g has been identified as the temperature at which τ_c begins to show temperature dependence. While both methods give values of T _g close to those obtained from differential scanning calorimetry, it is concluded that more work is required to establish spin-probe ESR as a reliable technique for the determination of T _g.