Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important pre... more Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important predictor of quality of life. Past studies showed that some aspects of cognition, such as working memory, can be enhanced following dopaminergic therapy and transcranial magnetic ...
Metal complexes of Schiff base derived from 2-furancarboxaldehyde and 2-aminobenzoic acid (HL) ar... more 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 25°C 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.
A macrocyclic Schiff-base (H2L) ligand is prepared via condensation of 2,6-pyridine dicarboxaldeh... more A macrocyclic Schiff-base (H2L) ligand is prepared via condensation of 2,6-pyridine dicarboxaldehyde with triethylene tetramine. The ligand is characterized using elemental analysis, by mass spectrometry, infrared (IR) spectroscopy, and proton nuclear magnetic resonance spectroscopy. The corresponding 1:1 metal complexes with Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Cd(II), UO2(II), and Th(IV) are additionally characterized by determining their magnetic moment, molar conductance, thermal analysis (thermogravimetry and differential thermoanalysis), and solid reflectance measurements. The complexes have the general formulae [M(H2L)(H2O)](X) n · yH2O (X = Cl or AcO, n = 2,3, y = 2–5) except for the Th(IV) complex having the formula [Th(H2L)(Cl)]Cl3. The molar conductance data reveal that all the metal chelates are electrolytes. IR spectra show that H2L is coordinated to the metal ions in a neutral pentadentate manner with 5N donor sites of the two azomethine–N, pyridine–N, and two amino–NH groups. The magnetic and solid reflectance spectra reveal that the complexes are octahedral. Thermal analysis shows that the complexes decompose in four to five steps. The activation thermodynamic parameters are calculated using the Coats–Redfern method. The parent Schiff base and its eight metal complexes were assayed against four bacterial species, two Gram negative, and two Gram positive. The Schiff base and five of its metal complexes showed antibacterial activity at different rates. The complexes Cr(III) and Cu(II) inhibited Gram-positive bacteria, while Co(II) complex inhibited all tested bacteria greater than the parent Schiff base. Three metal complexes (Ni, Cd, and Th) completely missed antibacterial activity.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2005
Cerium(IV), Thorium(IV) and Uranyl(II) complexes with the ammonium salt of sulfasalazine drug (H2... more Cerium(IV), Thorium(IV) and Uranyl(II) complexes with the ammonium salt of sulfasalazine drug (H2SSZ, HL-) have been studied. The structures of the complexes were elucidated using elemental analysis, IR and mass spectroscopy and thermal analysis. The complexes were isolated in 1:1 and 1:2 (M:L) ratios. The solid monocomplexes (1:1) (M:H(2)SSZ) were isolated in the general formulae [UO2(L)(H2O)2].2H2O and [M(L)(X)z(H2O)n].yH2O (M=Ce(IV) and Th(IV) (X=NO3, z=2, n=2, y=0-3)). The biscomplexes (1:2) (M:H2SSZ) solid chelates found to have the general formulae [UO2(HL)2].2H2O and [M(L)2(H2O)2] (M=Ce(IV) and Th(IV)). The thermal decomposition of the complexes should be discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coats-Redfern and Horwitz-Mitzger methods.
A simple, sensitive and accurate spectrophotometric method for the determination of sulphonamides... more A simple, sensitive and accurate spectrophotometric method for the determination of sulphonamides (sulphamethoxazole (SMZ), sulphaguanidine (SGD), sulphaquinoxaline sodium (SQX), sulphametrole (SMR), and sulphadimidine sodium (SDD)) has been developed. The charge-transfer reactions between sulphonamides as n-electron donors and 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, p-CLA) as π-acceptors resulting in highly coloured complexes were studied. Experimental conditions for these CT reactions were carefully optimised. Beer’s law is valid over the concentration ranges from 4–280 µg mL−1, 4–260 µg mL−1, 4–200 µg mL−1, and 4–200 µg mL−1 of SMZ, SGD, SQX, and SDD using DDQ reagent, respectively. While the calibration curves are linear in the concentration ranges from 4–180 µg mL−1, 4–80 µg mL−1, 4–60 µg mL−1, 4–180 µg mL−1, and 4–60 µg mL−1 of SMZ, SGD, SQX, SMR, and SDD, respectively, using TCNQ reagent and from 4–380 µg mL−1 and 4–300 µg mL−1 of SQX and SDD, respectively, using p-CLA reagent, respectively. Different analytical parameters, namely molar absorptivity (ε), standard deviation, relative standard deviation, correlation coefficient, limit of detection, and limit of quantification, were calculated. The results obtained by the proposed methods are in good agreement with those obtained by the official method as indicated by the percent recovery values.
... 2010, Vol. 31, No. 6 Moamen S. Refat et al. ... Chloroform, acetone, 1,4-dioxane, methylene c... more ... 2010, Vol. 31, No. 6 Moamen S. Refat et al. ... Chloroform, acetone, 1,4-dioxane, methylene chloride, 1,2-dichloroethane and dimethyl formamide were supplied from El-Nasr Company. The ALP pharmaceutical preparations were purchased from No-Uric capsules, 100 mg/cap. ...
International Journal of Environmental Health Research, 1996
... The present study is concerned with analyzing the situation of the administrative structure, ... more ... The present study is concerned with analyzing the situation of the administrative structure, clinical activities, and waste management system present in the MOH hospitals in Cairo Governorate. ... These were conducted with officials from MOH at the central and hospital levels. ...
Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important pre... more Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important predictor of quality of life. Past studies showed that some aspects of cognition, such as working memory, can be enhanced following dopaminergic therapy and transcranial magnetic ...
Metal complexes of Schiff base derived from 2-furancarboxaldehyde and 2-aminobenzoic acid (HL) ar... more 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 25°C 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.
A macrocyclic Schiff-base (H2L) ligand is prepared via condensation of 2,6-pyridine dicarboxaldeh... more A macrocyclic Schiff-base (H2L) ligand is prepared via condensation of 2,6-pyridine dicarboxaldehyde with triethylene tetramine. The ligand is characterized using elemental analysis, by mass spectrometry, infrared (IR) spectroscopy, and proton nuclear magnetic resonance spectroscopy. The corresponding 1:1 metal complexes with Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Cd(II), UO2(II), and Th(IV) are additionally characterized by determining their magnetic moment, molar conductance, thermal analysis (thermogravimetry and differential thermoanalysis), and solid reflectance measurements. The complexes have the general formulae [M(H2L)(H2O)](X) n · yH2O (X = Cl or AcO, n = 2,3, y = 2–5) except for the Th(IV) complex having the formula [Th(H2L)(Cl)]Cl3. The molar conductance data reveal that all the metal chelates are electrolytes. IR spectra show that H2L is coordinated to the metal ions in a neutral pentadentate manner with 5N donor sites of the two azomethine–N, pyridine–N, and two amino–NH groups. The magnetic and solid reflectance spectra reveal that the complexes are octahedral. Thermal analysis shows that the complexes decompose in four to five steps. The activation thermodynamic parameters are calculated using the Coats–Redfern method. The parent Schiff base and its eight metal complexes were assayed against four bacterial species, two Gram negative, and two Gram positive. The Schiff base and five of its metal complexes showed antibacterial activity at different rates. The complexes Cr(III) and Cu(II) inhibited Gram-positive bacteria, while Co(II) complex inhibited all tested bacteria greater than the parent Schiff base. Three metal complexes (Ni, Cd, and Th) completely missed antibacterial activity.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2005
Cerium(IV), Thorium(IV) and Uranyl(II) complexes with the ammonium salt of sulfasalazine drug (H2... more Cerium(IV), Thorium(IV) and Uranyl(II) complexes with the ammonium salt of sulfasalazine drug (H2SSZ, HL-) have been studied. The structures of the complexes were elucidated using elemental analysis, IR and mass spectroscopy and thermal analysis. The complexes were isolated in 1:1 and 1:2 (M:L) ratios. The solid monocomplexes (1:1) (M:H(2)SSZ) were isolated in the general formulae [UO2(L)(H2O)2].2H2O and [M(L)(X)z(H2O)n].yH2O (M=Ce(IV) and Th(IV) (X=NO3, z=2, n=2, y=0-3)). The biscomplexes (1:2) (M:H2SSZ) solid chelates found to have the general formulae [UO2(HL)2].2H2O and [M(L)2(H2O)2] (M=Ce(IV) and Th(IV)). The thermal decomposition of the complexes should be discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coats-Redfern and Horwitz-Mitzger methods.
A simple, sensitive and accurate spectrophotometric method for the determination of sulphonamides... more A simple, sensitive and accurate spectrophotometric method for the determination of sulphonamides (sulphamethoxazole (SMZ), sulphaguanidine (SGD), sulphaquinoxaline sodium (SQX), sulphametrole (SMR), and sulphadimidine sodium (SDD)) has been developed. The charge-transfer reactions between sulphonamides as n-electron donors and 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, p-CLA) as π-acceptors resulting in highly coloured complexes were studied. Experimental conditions for these CT reactions were carefully optimised. Beer’s law is valid over the concentration ranges from 4–280 µg mL−1, 4–260 µg mL−1, 4–200 µg mL−1, and 4–200 µg mL−1 of SMZ, SGD, SQX, and SDD using DDQ reagent, respectively. While the calibration curves are linear in the concentration ranges from 4–180 µg mL−1, 4–80 µg mL−1, 4–60 µg mL−1, 4–180 µg mL−1, and 4–60 µg mL−1 of SMZ, SGD, SQX, SMR, and SDD, respectively, using TCNQ reagent and from 4–380 µg mL−1 and 4–300 µg mL−1 of SQX and SDD, respectively, using p-CLA reagent, respectively. Different analytical parameters, namely molar absorptivity (ε), standard deviation, relative standard deviation, correlation coefficient, limit of detection, and limit of quantification, were calculated. The results obtained by the proposed methods are in good agreement with those obtained by the official method as indicated by the percent recovery values.
... 2010, Vol. 31, No. 6 Moamen S. Refat et al. ... Chloroform, acetone, 1,4-dioxane, methylene c... more ... 2010, Vol. 31, No. 6 Moamen S. Refat et al. ... Chloroform, acetone, 1,4-dioxane, methylene chloride, 1,2-dichloroethane and dimethyl formamide were supplied from El-Nasr Company. The ALP pharmaceutical preparations were purchased from No-Uric capsules, 100 mg/cap. ...
International Journal of Environmental Health Research, 1996
... The present study is concerned with analyzing the situation of the administrative structure, ... more ... The present study is concerned with analyzing the situation of the administrative structure, clinical activities, and waste management system present in the MOH hospitals in Cairo Governorate. ... These were conducted with officials from MOH at the central and hospital levels. ...
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Papers by Gehad Ahmed