Europium(III) was extracted by bis(2-ethylhexyl)phosphoric acid (HDEHP) and 8-hydroxyquinoline (HQ) in dodecane from aqueous perchlorate media of constant ionic strength (0.1M; H+, NaClO4). Slope analysis of the data indicate that three molecules of HDEHP or HQ are attached to Eu3+. Extraction constants were obtained at different temperatures. The data were used to calculate the thermodynamic parameters (G, H and S) for the extraction process in the two systems. When using mixtures of crown ethers with HDEHP no synergism was observed.
The extraction of Co2+ from a 0.1M ionic strength aqueous phase (Na+, CH3COOH) of pH=5.1 was studied using thenoyltrifluoroacetone, HTTA, in eight different solvents and HTTA+trioctylphosphine oxide,
TOPO, in the same solvents. A comparisons of the effect of solvent dielectric constants on the equilibrium constant shows
a synergism as a result of the increased hydrophobic character imparted to the metal complex due to the formation of the TOPO
The extraction of Co(III) from aceticacid-acetate buffer solutions with various mixtures of ligands has been studied. Thenoyltrifluoroacetone
mixed with triphenylphosphine oxide, trioctylphosphine oxide or tributyl phosphate were used as extractants. The effect of
different parameters affecting the distribution ratio was studied in detail. Also, the corresponding thermodynamic parameters
are calculated and discussed, together with the structures of extracted species.
Authors:A. Bahgat, M. Ahmed, A. Barakat, and T. Ramadan
A stone of brick-like shape, measuring roughly 25×12.5×10.5 cm3 and weighing 14 kg was found in 1983, in the western desert of Egypt. The meteorite was named El-Bahrain meteorite and classified as L-chondrite. In the present paper, the principal constituents of El-Bahrain meteorite have been studied by means of Mössbauer spectroscopy. The chemical composition as obtained by the conventional wet analyses of L-chondritic meteorites showed that the meteorite contains 23.38% Fe and 1.23% Ni. While the analysis of the atomic absorption showed the presence of 27.03% as a total iron. The Mössbauer analysis of El-Bahrain meteorite showed that the iron constituent minerals were determined to be olivine, metallic iron-nickel alloys (kamacite, taenite and tetrataenite), ferrous sulfide (troilite) and weathering products such as maghemite and nanocrystalline hematite. The structure of meteoritic iron obtained by the Mössbauer analysis has been discussed on the basis of these constituents.
Authors:A. Ramadan, M. Mahmoud, S. Khalifa, and N. Souka
The extraction of Eu(III) by dinonylnaphthalenesulfonic acid (HDNNS) in benzene from nitrate and perchlorate solutions has been investigated. For nitrate solutions the ionic strength of the aqueous phase was kept constant at 0.1M using NaNO3–HNO3 mixtures. The Eu distribution was measured at different temperatures. The following stoichiometric formulae for the Eu species in benzene were derived: Eu(NO3) (Hn–1 (DNNS)n)2 and Eu(Hn–1 (DNNS)n)3, from the nitrate and perchlorate medium respectively (n being a small number, e.g. 1, 2 or 3). The equilibrium constants were calculated and the thermodynamic parameters of the system were determined. When adding dibenzo-24-crown-8, dicyclohexyl-18-crown-6 or trioctylphosphine oxide, no synergism, but rather antagonism was observed.
Authors:M. Masoud, A. El-Merghany, A. Ramadan, and M. Abd El-Kaway
The mechanism of the decomposition of the entitled compounds and their complexes is studied. Adenine, its Schiff base of salicylaldehyde,
and its azo resorcinol derivatives are ended with carbon. However, oxalonitrile compound is appeared as a final product for
adenine acetylacetone and an intermediate for adenine. The thermodynamic parameters of the decomposition reaction were evaluated
and discussed. The change of entropy values, ΔS#, showed that the transition states are more ordered than the reacting complexes. The thermal processes proceed in complicated
mechanisms where the bond between the central metal ion and the ligands dissociates after losing small molecules such as H2O, NH3, or HCl. In most cases, the free radical species of the ligands are assigned to exist through decomposition mechanisms. The
copper adenine and nickel salicylaldehyde complexes are ended with the metal as a final product. However, the cobalt adenine,
its acetylacetone, its salicylaldehyde, cadmium and mercury guanine complexes are ended with metal oxides.
Authors:M. F. Hassan, F. M. Momen, A. K. Nasr, A. H. Mabrouk, and M. M. Ramadan
The laelapid mites Cosmolaelaps keni and Laelaspis astronomicus beside the rhodacarid mite Protogamasellopsis denticus are biological control agents and being native predators in Egypt. In order to raise active population of above species, the biology and demographic parameters, of the three tested species were observed under laboratory conditions with eggs of Ephestia kuhniella. All predatory species were developed and reproduced with E. kuhniella eggs. The mean developmental and oviposistion periods of L. astronomicus females were the longest from the other tested species. The mean longevity of C. keni was longer than that of P. denticus. Cosmolaelaps keni consumed more E. kuhniella eggs during the oviposition and adult longevity periods than other species did. Protogamasellopsis denticus fed on E. kuhniella food gave the most rate of oviposition as shown by the maximum fertility, net reproductive rate and gross reproductive rate. Laelaspis astronomicus preying on E. kuhniella eggs gave the longest generation time, lowest rate of fecundity and all life table parameters compared to other tested species; therefore E. kuhniella eggs was appropriate for the oviposition of P. denticus and C. keni rather than L. astronomicus.
This study is the first to report that E. kuhniella eggs were an acceptable factitious food for P. denticus, L. astronomicus and C. keni.
Authors:M.A. Elfattah, R.M. Elsanhoty, M.F. Ramadan, and M.O. Osman
The main objective of this work was to evaluate the composition, nutritional, physical and rheological properties of wheat flour and dough from genetically modified wheat (Triticum aestivum L.) Hi-Line 111 (GMW) compared to conventional wheat (non-GMW). Analyses were conducted to measure the proximate chemical composition with references to 18 components including total solid, protein, lipids, crude fiber, ash, carbohydrate, minerals, amino acids, and fatty acids. In addition, physical and rheological properties such as water absorption, arrival time, dough development time, stability value, dough weakening value, extensibility of dough, resistance to extension, and ratio of resistance/extensibility were evaluated. The results showed that there were no significant differences between GMW and non-GMW in terms of chemical composition. Results revealed the presence of saturated and unsaturated fatty acids wherein there were no significant differences between GMW and its counterpart in the levels of fatty acids. In addition, there were no significant differences on the levels of amino acids. In addition, there were no significant differences between the GMW and non-GMW in the physical and rheological properties. From these results, it can be concluded that GMW Hi-Line 111 is confirmed to have nearly the composition and rheological properties as non-GMW.
Authors:Nesrin K. Ramadan, Tagreed A. Mohamed, Rowayda M. Fouad, and Azza A. Moustafa
Two sensitive, specific, and selective stability-indicating chromatographic methods were developed for the determination of cyclobenzaprine HCl (CZ) and asenapine maleate (AS) in pure forms, in the presence of their degradation products and in their pharmaceutical formulations. The first method was an isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). Analysis was performed on cyano column using a mobile phase consisting of acetonitrile–(0.05 m) potassium dihydrogen phosphate buffer (pH 3 ± 0.1) (70:30, v/v) with a flow rate of 1.5 mL min−1 and ultraviolet (UV) detection at 290 nm for the determination of CZ, and methanol–(0.05 m) potassium dihydrogen phosphate buffer (pH 6 ± 0.1) (70:30, v/v) with a flow rate of 1.5 mL min−1 and UV detection at 220 nm for the determination of AS. The second method was thin-layer chromatography (TLC), using silica gel 60 F254 plates and toluene–methanol–chloroform-ammonia solution 33% (5:3:6:0.1, by volume) as the mobile phase for the two drugs. The spots were scanned densitometrically at 290 and 220 nm for the determination of CZ and AS, respectively. The methods were validated according to the International Conference on Harmonization (ICH) guidelines, and the acceptance criteria for linearity, accuracy, precision, specificity, and system suitability were met in all cases. The linearity ranges were 2.5–25 μg mL−1 for the RP-HPLC method and 5–50 μg band−1 for the TLC method for both drugs. The limits of detection for the RP-HPLC method were 0.250 and 0.578 for CZ and AS, respectively, while the limits of quantification were 0.758 and 1.572 for CZ and AS, respectively. The limits of detection for the TLC method were 1.355 and 1.284 for CZ and AS, respectively, while the limits of quantification were 4.472 and 3.891 for CZ and AS, respectively. The results were compared statistically at a 95% confidence level with the reported methods. There were no significant differences between the mean percentage recoveries and the precisions of the two methods.