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Abstract  

Complexes resulted from the interaction of [Ph3P]3RuCl2 with 2-aminoethylpyridine (aepy), 2-hydrazinopyridine (hzpy) and dipicolylamine (dpa) with KPF6 have been isolated from ethanol. The structures of the complexes were investigated using elemental analyses, IR, magnetic moment, UV-Vis and 1H NMR spectroscopy. The complexes have been isolated as [Ru(hzpy)3](PF6)2, [Ru(hzpy)2(aepy)](PF6)2, [Ru(hzpy)(aepy)2](PF6)2, [Ru(dpa)2](PF6)2 in an octahedral geometry. The thermal decomposition of complexes was discussed in terms of their structures and the thermodynamic parameters were evaluated. The metal complexes were screened for their antibacterial activity against bacterial species, Escherichia coli, Staphylococcus aureus, as well as fungus (Candida). The activity data show the metal complexes have potent antibacterials against one ore more bacterial species.

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Abstract  

Formation constants (logK MAL MA) of the mixed complexes of the type M–A–L (where M=Mn(II), Co(II), Ni(II), Cu(II), Ce(III), Th(IV), and UO2(II); A=oxine and L=sulphamerazine or sulphadiazine) have been determined pH-metrically in 60% (v/v) ethanol–water mixture at 25°C and constant ionic strength (μ=0.1 M NaCl). The mode of chelation was ascertained by conductivity measurements. The stability sequence with respect to metal ions have been found to be Cu(II)>Ni(II)>Co(II)>Mn(II) and Th(IV)>UO2(II)>Ce(III). CuAL ternary solid complexes have been prepared and characterized on the basis of elemental analysis and IR-spectroscopy. The thermal degradations of the prepared complexes are discussed in an attempt to assign the intermediate compounds formed.

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Abstract  

Tin(II) and tin(IV) are absorbed from aqueous solutions by Sephadex G-25 gel, from which they can be eluted by humates or fulvates, with which they interact more strongly. Methyltin species are not absorbed by Sephadex G-25, and so can be separated from inorganic tin. Both inorganic tin and methyltin species in natural waters at pH 7.4 can be quantitatively retained by passing through small columns of Chelex-100 resin: the methyltin species can then be washed off the resin with 4M nitric acid. Trimethyltin chloride113Sn in water scarcely interacts with fulvates, humates, kaolinite or montmorillonite but is absorbed bySphagnum peat. Dimethyltin dichloride-113Sn reacts significantly with all the above materials after 2 hours equilibration. Methyltin trichloride-113Sn interacts weakly in alkaline solutions.

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Summary The unit cell parameters of virgin and thermally treated potassium hexacyanoferrate(II)trihydrate (KFCT) crystals are measured at room temperature. Considerable changes in the lattice constants are observed for as-grown or pre-cooled to the liquid nitrogen temperature samples after heating up to selected higher temperatures for different times. The detected variations may be due to partial or total removal of the three water molecules of crystallization and the transformation of Fe2+ to Fe3+. DSC, DTA and TG are used to study physical and chemical changes associated with the observed crystallographic variations. The effect of γ-irradiation with a dose of 5×105 Gy on the crystal structure of KFCT is also examined. Two computer software programs are used to analyze the data of the X-ray diffraction patterns and the results are compared.

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Transition metal complexes of heterocyclic Schiff base

Biological activity, spectroscopic and thermal characterization

Journal of Thermal Analysis and Calorimetry
Authors:
M. Omar
,
G. Mohamed
, and
A. Hindy

Abstract  

Metal complexes of Schiff base derived from 2-furancarboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, solid reflectance, magnetic moment, molar conductance and thermal analysis. The ligand dissociation as well as the metal-ligand stability constants have been calculated pH-metrically at 25C and ionic strength μ=0.1 (1 M NaCl). The complexes are found to have the formulae [M(HL)2](X)n yH2O (where M=Fe(III) (X=Cl, n=3, y=4), Co(II) (X=Cl, n=y=2), Ni(II) (X=Cl, n=y=2), Cu(II) (X=Cl, n=y=2) and Zn(II) (X=AcO, n=y=2)) and [UO2(L)2]2H2O. The thermal behaviour of these chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The ligand and its metal complexes show a biological activity against some bacterial species.

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Water stress is a severe limitation for crop growth especially in arid and semi-arid regions of the world, as it has a vital role in plant growth and development at all growth stages. The aim of the present study was to evaluate the differential responses of twelve sunflower genotypes to three levels of water supply and select the most suitable one for such conditions. Two field experiments were conducted under adequate (7140 m3/ha), moderate (4760 m3/ha) and severe (2380 m3/ha) water regimes to evaluate the chlorophyll index, transpiration rate, leaf water content, plant height, head diameter, seeds/head, 1000-seed weight, seed and oil yield of the genotypes. Moderate and severe levels of drought had a significant impact on the transpiration rate, leaf water content, yield-contributing characters and oil yield of all the sunflower genotypes. However, the sunflower genotypes showed different responses to the different water regimes. The highest seed and oil yields were attained in L990 and Giza 102 in the case of adequate water supplies, while L38 was the best under moderate and severe drought conditions. On the basis of the results, sunflower genotype L990 could be recommended for growing when adequate water supplies are available, and L38 under moderate and severe water regimes to obtain high seed and oil yields.

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Summary

A high performance liquid chromatographic method was developed for the quantitative determination of the active components of silymarin in the leaves of Silybum marianum during different growth stages. In this study, taxifolin and six main active constituents in silymarin, including silydianin, silychristin, diastereomers of silybin (silybin A and B) and diastereomers of isosilybin (isosilybin A and B) were completely separated on a 5-μm ODS column (Luna, Phenomenex, USA) with a mobile phase consisting of methanol and 5 mM NaH2PO4 (pH 3.5 adjusted with phosphoric acid) in a ratio of 45:55 v/v. Quantitation was performed with UV detection at 280 nm, based on peak area. The concentration of each component, as well as the total silymarin concentration was determined and compared with those of the seeds, aiming at optimizing the utilization of the cultivated plant. The developed method was validated with respect to linearity, range, specificity, accuracy, precision, and robustness. The leaves were found to contain such concentrations of silymarin components that the yield is better per field area than that from the seeds. Moreover, the extraction of these components from leaves is nonexpensive and simpler than the extraction from seeds.

Open access
Acta Chromatographica
Authors:
Maha F. Abdel-Ghany
,
Omar Abdel-Aziz
,
Miriam F. Ayad
, and
Mariam M. Tadros

New, simple, selective, and sensitive liquid chromatography–ultraviolet (LC–UV) methods have been developed and subsequently validated for simultaneous determination of linagliptin–empagliflozin combination and simultaneous determination of alogliptin benzoate–pioglitazone hydrochloride combination. Linearity was found to be acceptable over the concentration ranges of 2–50 μg mL−1, 4–100 μg mL−1, 0.5–25 μg mL−1, and 1–25 μg mL−1 for linagliptin (LNG), empagliflozin (EMG), alogliptin (ALG), and pioglitazone (PGN), respectively. All the methods were applied successfully to the analysis of the pharmaceutical dosage forms. The optimized methods were validated and proved to be robust and accurate for the quality control of the mentioned drugs in their different pharmaceutical dosage forms.

Open access

For evaluating the age-related change in noradrenaline (NA)-induced contraction of isolated rat carotid artery (CA), the effect of α and β adrenoreceptor (AR) blockers and the role of nitric oxide (NO) were investigated. Methods: Concentration-response curves to NA (10−10–10−4 M) and α1 agonist phenylephrine (PE; 10−10–10−5 M) were constructed in isolated CA rings from young and middle-aged rats. The effects of nitric oxide synthase (NOS) inhibitor (L-NAME; 100 μM), α1-AR antagonist (prazosin; 0.1 μM), α2-AR antagonist (yohimbine; 0.1 μM) and β-AR antagonist (propranolol; 1 μM) on NA-induced contraction of isolated CA rings were examined. In CA rings preconstricted with NA, the responses to α2-AR agonist (clonidine; 10−7–10−5 M), β-AR agonist (isoprenaline; 10−8–10−5 M),), sodium nitroprusside (SNP; 10−9–10−5 M) were assessed. Results: The maximum contractile response of CA to NA and to PE was higher in younger than in middle-aged rats. Prazosin reduced the contractile response to NA in both groups, while propranolol, yohimbine and L-NAME did not affect NA-induced contraction in either of them. Clonidine, isoprenaline and SNP produced a dose-dependent vasorelaxation of CA rings, isoprenaline-induced vasodilatation was lower in middle-aged rats, while there was no difference in clonidine or SNP-induced relaxant effect between the two groups. Conclusions: NA-induced contraction of isolated rat CA rings is decreased in old rats, this is related to α1-AR. β-AR mediated dilatation was compromised in middle-aged rats (endothelium-dependent). α2-AR and SNP-mediated dilator effect seems to be unchanged.

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Abstract

Soybean is one of the most important leguminous crops that contributes to human alimentation and animal feed. Soybean grain with its high protein and valuable lipid content is an essential component for the food and feed industries worldwide. Apart from the genetically determined quality characteristics of a certain variety, management practices may have an influence on the manifestation of quality parameters. At the Department of Agronomy, Hungarian University of Agriculture and Life Sciences, agronomic impacts on grain yield, protein and lipid content of soybean crop has been studied in a replicated field trial. Nitrogen (N) application and various means of weed control were studied, and grain yields were evaluated in accordance with the treatments. The results obtained suggest, that N topdressing has positive but no significant effect on grain yield, however, the means of weed control resulted in an almost twofold yield improvement compared to the control. The treatments had diverse effects regarding both protein and lipid contents of the crop yield, however, significant protein and lipid yield improvement of the crop could be observed.

Open access