Reactions with heterocyclic amidines 1. Cyanoethylation of cyclic amidines

2-Amino-5-phenyl-1,3,4-oxadiazole ( 1a ) and 2-amino-1,3,4-thiadiazole ( 1b ) reacted with acrylonitrile to yield β-cyanoethylamino derivatives. On the other hand, 2-amino-4-phenylthiazole ( 2 ) reacted with acrylonitrile under the same experimental conditions to yield a di-β-cyanoethylaminothiazole derivative. 3-Phenyl-Δ²-1,2,4-triazoline-5-thione reacted with acrylonitrile to yield the corresponding adduct. The structure of the adduct was established by its conversion into the acid 13 which could be synthesised via another independent route.     

Gnapholide: a new guaiac-dimer from Pulicaria gnaphalodes (Asteraceae)

The ethyl acetate soluble part of the chloroform extract of Pulicaria gnaphalodes belonging to the family Asteraceae afforded a new sesquiterpene-dimer of guaiane class named as gnapholide and anabsinthin of the same skeleton. The structures of both the compounds were elucidated with the aid of spectroscopic techniques including 2D NMR.     

Statistical analysis of HDPE fatigue lifetime

Fatigue lifetime of HDPE structures such as pipes is recognized to show a large scatter. This study aims to compare different statistical methods and distributions, in order to give convenient modeling of tensile and fatigue test results of commercially available polyethylene compression molded sheets. The median rank, the maximum likelihood and the Kolmogorov-Smirnov fitting are compared for the estimation of Weibull parameters. The choice of the best distribution to fit fatigue lifetime is discussed on the basis of the goodness-of-fit results. It is found that whether the three-parameter distributions of Weibull and lognormal types are suitable for lifetime prediction, the two-parameter Weibull is more conservative for probabilistic fatigue design.     

Synthesis,characterization, DNA interaction,thermal and in vitro biological activity investigation of some Ni(II)-Isatin bishydrazone complexes

Complexes of the type [Ni (L) (H₂O)] Cl₂.nH₂O, where L = [(pyridine-2-carboxaldhyde)-3-isatin]-bishydrazone (cpish), [(2-acetyl pyridine)-3-isatin]-bishydrazone (apish) and [(2-benzoyl pyridine)-3-isatin]-bishydrazone (bpish) have been synthesized and characterized on the bases of elemental analysis, molar conductance, IR, NMR, electronic spectra and thermal analysis (TGA and DTA). Moreover, the stoichiometry and the formation constants of these complexes have been determined spectrophotometrically. Kinetics and thermodynamic parameters of the thermal decomposition have been computed from the thermal data using Coats and Redfern method, which confirm first-order kinetics. The bioefficacy of the ligands and their complexes have been examined for their in vitro antibacterial and antifungal activity against many types of bacteria and anti fungal cultures, which are common contaminants of the environment in Egypt, and the results indicate that the ligands and their metal complexes possess notable antimicrobial activity. Investigation of their interaction with CT-DNA under physiological conditions, using spectroscopic (UV–visible) and hydrodynamic techniques (viscosity measurements). Binding constant "K _b" obtained from spectroscopic methods revealed significant binding of compounds with DNA via intercalation, Furthermore, free energies of compounds–DNA interactions indicated spontaneity of their binding.     

Study of H-bonded assemblies of the solvates of anthracene derivatives: guest effect on the crystal symmetry and spectroscopic properties

Two solvates of title compound 1-acetyl-3-naphthyl-5-(9-anthryl)-2-pyrazoline solvate(ANNP) (1a) with chloroform (1b) and acetic acid (1c) and a single crystal of another title compound 1-acetyl-3-(4-chloro)phenyl-5-(9-anthryl)-2-pyrazoline (ACAP) (2a) and its adduct with phenol (2b) were afforded via solution growth technique. The structure of these solids were confirmed and verified by multiple techniques such as single crystal X-ray diffraction (SCXRD) analysis, PXRD, DSC/TGA and Infrared spectroscopy. Structural analysis indicates that guest inclusion results not only in stronger hydrogen bonds, but also in a larger number of favourable C–H?π interactions between ANNP/ACAP molecules. The solvates show symmetry reduction guest effect comparing with the guest free molecules of ANNP and ACAP. Moreover, characteristic changes have been observed in the Infrared bands of the solvates owing to the formation of hydrogen bonds between host–guest.     

Fabrication and characterization of nanocrystalline Al,Co:ZnO thin films by a sol–gel dip coating

The consequence of annealing on the micro-structural and electrochemical characteristics of Al doped CoZnO thin films deposited by sol–gel dip coating technique are studied. X-ray diffraction indicates that films have a hexagonal wurtzite structure oriented towards the (100). Optical properties of films are recorded by transmission curves utilising a UV–VIS spectrophotometer. The investigation of the optical transmission spectra indicates that the band gap of the films decrease from 3.99 eV to minimum 3.83 eV upon annealing. All films show room temperature ferromagnetism whose magnetization increases with annealing. Dip coated films possess polycrystalline nanosized grains with porous morphology.     

On a Cotangent Bundle with Deformed Riemannian Extension

The main purpose of this paper is to study deformed Riemannian extensions in the cotangent bundle. The curvature properties of metric connections for deformed Riemannian extensions are also investigated.     

On the existence of strong Nash equilibria

This paper investigates the existence of strong Nash equilibria (SNE) in continuous and concave games. It is shown that the coalition consistency property introduced in the paper, together with concavity and continuity of payoffs, permits the existence of SNE in games with compact and convex strategy spaces. We also characterize the existence of SNE by providing necessary and sufficient conditions. We suggest an algorithm for computing SNE. The results are illustrated with applications to economies with multilateral environmental externalities and to the static oligopoly model.     

Fullerene‐β‐Cyclodextrin Conjugate Based Electrochemical Sensing Device for Ultrasensitive Detection of p‐Nitrophenol

The article describes the use of a fullerene (C₆₀)‐β‐cyclodextrin conjugate, synthesized via 1,3‐dipolar cycloaddition, for the ultrasensitive electrochemical detection of p‐nitrophenol. This conjugate was successfully immobilized on the surface of a glassy carbon electrode and the developed device showed high activity towards p‐nitrophenol due to the synergetic effect of C₆₀, the latter becoming highly conductive upon reduction. The determination of p‐nitrophenol was performed by using square wave voltammetry over a concentration range from 2.8×10^?9 mol L^?1 to 4.2×10^?7 mol L^?1 and the detection limit was calculated to be 1.2×10^?9 mol L^?1.