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Search Results: 1 - 10 of 460052 matches for " Iqbal M. I. Ismail "
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Kinetics of Degradation of Eosin Y by One of the Advanced Oxidation Processes (AOPs)—Fenton’s Process  [PDF]
Ashraf Hossain, A. B. M. Sadique Rayhan, Md. Jahir Raihan, Aklima Nargis, Iqbal M. I. Ismail, Ahsan Habib, Abu Jafar Mahmood
American Journal of Analytical Chemistry (AJAC) , 2016, DOI: 10.4236/ajac.2016.712074
Abstract: Kinetics of homogeneous degradation of Eosin Y (EY), also known as Acid red 87 (CI 45380), are studied, mostly using Fenton’s process, at 30 by monitoring its absorbance at 517 nm (λmax of EY). This process is one of the advanced oxidation processes (AOPs). Mixture of H2O2 and Fe(II) ion in acetate buffer medium (pH 2.74 - 4.56) generates hydroxyl free radicals (?OH) which attack the dye molecules, resulting in degradation of the dye molecules. Results show that the initial rate of EY degradation decreases with the increasing of solution pH because of removal of kinetically important Fe (iron) species through formation of ferric hydroxide. On the other hand, the rate increases with increasing the?concentrations of H2O2, Fe(II) and EY at low solution pH. The initial rate increases with increasing of concentration of H2O2 and, subsequently remains unaffected with further increase of its concentration at a constant Fe(II) concentration because of the enhanced scavenging environment created by H2O2 at its higher concentration. The initial rate also increases with increasing of concentration of Fe(II) at a constant H2O2 concentration and remains unaffected with its further increase. EY concentration also enhances the initial rate at low pH. However, the initial rate is significantly enhanced by UV light. This is because of formation of additional hydroxyl radicals through excitation of the dye molecules by UV light. During the period of experiment, EY in aqueous solution alone hardly suffered any degradation. Degradation mechanism of EY by the Fenton and photo-Fenton’s processes is also discussed. Statistical analysis was used to validate the experimental results. Low values of the standard deviation for both the initial rate and % degradation indicated the consistency of the experimental data.
Synthesis and characterization of ZnO-TiO2 nanocomposites and their application as photocatalysts
Md Ahsan Habib, Md Tusan Shahadat, Newaz Mohammed Bahadur, Iqbal M I Ismail and Abu Jafar Mahmood
International Nano Letters , 2013, DOI: 10.1186/2228-5326-3-5
Abstract: Nanocomposite ZnO-TiO2 powders of varying ZnO/TiO2 molar ratios have been prepared from their salt/compound by heating at 600°C and 900°C and characterized using scanning electron microscope and X-ray diffraction techniques. The nanosized powders can decolorize/degrade brilliant golden yellow (BGY), an azo dye extensively used in textile industries, in water under solar irradiation. The effects of various parameters such as photocatalyst loading, molar ratio of ZnO/TiO2, pH of the solution, initial dye concentration, and irradiation time on the photodecolorization have been investigated. ZnO-TiO2 nanocomposite (6 g/L) in the molar ratio of 1:1 or 3:1, prepared at 900°C, can efficiently decolorize about 98% of 20 mg/L BGY at pH of about 7 by 2-h illumination in sunlight. The initial dye decolorization follows pseudo-first-order kinetics. Finally, trial experiments were done using real textile wastewater to find out the effectiveness of the photocatalysts to a more complex system.
5,5-Dimethyl-2,2-bis(pyridin-2-yl)-1,3-diazinane
Ismail Warad,Afaf Alruwaili,Saud I. Al-Resayes,M. Iqbal Choudhary
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812021629
Abstract: In the molecule of the title compound, C16H20N4, the 1,3-diazinane ring adopts a chair conformation and the dihedral angle formed by the pyridine rings is 78.64 (8)°. The molecular conformation is stabilized by an intramolecular C—H...N hydrogen bond, forming an S(6) ring motif. In the crystal, centrosymmetrically related molecules are linked into dimers by pairs of N—H...N hydrogen bonds, generating rings of R22(10) graph-set motif.
Square-Wave Adsorptive Cathodic Stripping Voltammeteric Determination of Manganese (II) Using a Carbon Paste Electrode Modified with Montmorillonite Clay  [PDF]
Amr M. Beltagi, Iqbal M. Ismail, Mohamed M. Ghoneim
American Journal of Analytical Chemistry (AJAC) , 2013, DOI: 10.4236/ajac.2013.44025
Abstract:

Manganese is an essential micronutrient for all organisms; however at high concentrations it has a toxic effect. Manganese toxicity is a serious constraint to crop cultivation since it is taken-up by plants and can easily be passed into the food chain again causing symptoms of Parkinson’s disease. A fully validated square-wave adsorptive cathodic stripping voltammetry method has been developed for determination of Mn (II) as a complex with 2-(5’-bromo-2’-pyridylazo) 5-diethylaminophenol in aqueous solutions using a carbon paste electrode (CPE) modified with montmorillonite-Na clay. The results showed that the modified CPE (90% (w/w) graphite powder and 10% (w/w) montmorillonite-Na clay) exhibited excellent electrochemical activity towards the investigated Mn (II) complex in acetate buffer of pH = 5.0. Factors affecting the performance of the modified carbon paste electrode and the sensitivity of the described square- wave stripping voltammetry method, including the electrode composition, concentration of ligand, pulse parameters and preconcentration conditions were examined. A detection limit (S/N = 3) of 0.015μg·L-1 (2.73 × 10-10 mol·L-1) Mn (II) was achieved when a preconcentration time of 240 s was applied. Insignificant interferences from various inorganic and organic species were estimated. The described square-wave adsorptive cathodic stripping voltammetry method coupled with the modified carbon paste electrode has been successfully applied to Mn (II) analysis in different water samples.

Biological Activities of Geranium wallichianum
Bashir Ahmad,Muhammad Ismail,Zafar Iqbal,M. Iqbal Chaudhry
Asian Journal of Plant Sciences , 2003,
Abstract: The crude extract of Geranium wallichianum was tested for antifungal, antibacterial, insecticidal, phytotoxic and cytotoxic activities. The extract displayed an overall moderate activity against human, animal and plant pathogens in antifungal bioassay and against Staphylococcus aureus in antibacterial activity. The extract did not display any remarkable activity in the rest of bioassays.
Seasonal prevalence of malaria in West Sumba district, Indonesia
Din Syafruddin, Krisin, Puji Asih, Sekartuti, Rita M Dewi, Farah Coutrier, Ismail E Rozy, Augustina I Susanti, Iqbal RF Elyazar, Awalludin Sutamihardja, Agus Rahmat, Michael Kinzer, William O Rogers
Malaria Journal , 2009, DOI: 10.1186/1475-2875-8-8
Abstract: Two stage cluster sampling malaria prevalence surveys were conducted in the wet season and dry season across West Sumba, Nusa Tenggara Province, Indonesia.Eight thousand eight hundred seventy samples were collected from 45 sub-villages in the surveys. The overall prevalence of malaria infection in the West Sumba District was 6.83% (95% CI, 4.40, 9.26) in the wet season and 4.95% (95% CI, 3.01, 6.90) in the dry. In the wet season Plasmodium falciparum accounted for 70% of infections; in the dry season P. falciparum and Plasmodium vivax were present in equal proportion. Malaria prevalence varied substantially across the district; prevalences in individual sub-villages ranged from 0–34%. The greatest malaria prevalence was in children and teenagers; the geometric mean parasitaemia in infected individuals decreased with age. Malaria infection was clearly associated with decreased haemoglobin concentration in children under 10 years of age, but it is not clear whether this association is causal.Malaria is hypoendemic to mesoendemic in West Sumba, Indonesia. The age distribution of parasitaemia suggests that transmission has been stable enough to induce some clinical immunity. These prevalence data will aid the design of future malaria control efforts and will serve as a baseline against which the results of current and future control efforts can be assessed.Accurate information about the burden of malaria infection at the district or provincial level is required both to plan local malaria control efforts and to measure the impact of such efforts. Although many studies of malaria epidemiology, immunology, and drug resistance have been conducted at many sites in Indonesia [1-7], there is little published literature describing malaria prevalence at the district, provincial, or national level. Therefore, point prevalence surveys for malaria, designed to estimate malaria prevalence in the West Sumba District of East Nusa Tenggara Province, Indonesia, were conducted. Previous
Synthesis, electrochemical, spectrophotometric and potentiometric studies of two azo-compounds derived from 4-amino-2-methylquinoline in ethanolic-aqueous buffered solutions
El-Attar, Mona A.;Ismail, Iqbal M.;Ghoneim, Mohamed M.;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012005000013
Abstract: two azo-compounds, 2-methyl-4-(5-amino-2-hydroxy-phenylazo)-quinoline (2) and 2-methyl-4-(2-hydroxy-5-nitrophenylazo)-quinoline, derived from 4-amino-2-methylquinoline were synthesized. their chemical structures were characterized and confirmed by means of elemental chemical analysis, infrared (ir) spectroscopy, 1h nuclear magnetic resonance (nmr) and mass spectrometry (ms). the electrochemical behavior of the starting compound (4-amino-2-methylquinoline) and of the two synthesized azo-derivatives was studied at the mercury electrode in the b-r universal buffer at various ph values (2-11.5) containing 40% (v/v) ethanol using dc-polarography, cyclic voltammetry and controlled-potential coulometry. their electrode reaction pathways were elucidated and discussed. the dissociation constants (pka) of the examined compounds, stability constants and stoichiometry of their complexes in solution with some transition metal ions (co(ii), ni(ii), cu(ii), la(iii) and uo22+) were determined.
[1,2-Bis(diphenylphosphanyl)ethane-κ2P,P′]dichloridopalladium(II) dimethyl sulfoxide monosolvate
Ismail Warad,Abdullah S. Aldwayyan,Fahad M. Al-Jekhedab,M. Iqbal Choudhary
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812028310
Abstract: In the title compound, [PdCl2(C26H24P2)]·C2H6OS, the PdII atom adopts a distorted cis-PdCl2P2 square-planar coordination geometry. The five-membered chelate ring adopts an envelope conformation with a methylene C atom in the flap position. The S and C atoms of the dimethyl sulfoxide (DMSO) solvent molecule are disordered over two sets of sites in a 0.8976 (18):0.1024 (18) ratio. The DMSO O atom accepts three C—H...O hydrogen bonds from an adjacent complex molecule.
Simulated Gastrointestinal pH Condition Improves Antioxidant Properties of Wheat and Rice Flours
Kim Wei Chan,Nicholas M. H. Khong,Shahid Iqbal,Maznah Ismail
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13067496
Abstract: The present study was conducted to evaluate the antioxidant properties of wheat and rice flours under simulated gastrointestinal pH condition. After subjecting the wheat and rice flour slurries to simulated gastrointestinal pH condition, both slurries were centrifuged to obtain the crude phenolic extracts for further analyses. Extraction yield, total contents of phenolic and flavonoids were determined as such (untreated) and under simulated gastrointestinal pH condition (treated). 1,1-diphenyl-2-picrylhydrazyl radical (DPPH ?) scavenging activity, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical cation (ABTS ?+) scavenging activity, ferric reducing antioxidant power (FRAP), beta-carotene bleaching (BCB) and iron chelating activity assays were employed for the determination of antioxidant activity of the tested samples. In almost all of the assays performed, significant improvements in antioxidant properties ( p < 0.05) were observed in both flours after treatment, suggesting that wheat and rice flours contain considerably heavy amounts of bound phenolics, and that their antioxidant properties might be improved under gastrointestinal digestive conditions.
Antioxidant Property Enhancement of Sweet Potato Flour under Simulated Gastrointestinal pH
Kim Wei Chan,Nicholas M. H. Khong,Shahid Iqbal,Imam Mustapha Umar,Maznah Ismail
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13078987
Abstract: Sweet potato is known to be rich in healthful antioxidants, but the stability of its antioxidant properties under gastrointestinal pH is very much unknown. Hence, this study aimed to evaluate the changes in antioxidant properties (total contents of phenolics and flavonoids as well as antioxidant activity) of sweet potato flour (SPF) under simulated gastrointestinal pH conditions. It was found that the yield of SPF crude phenolic extract increased from 0.29 to 3.22 g/100 g SPF upon subjection to gastrointestinal pH conditions ( p < 0.05). Also elevated significantly were the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of SPF ( p < 0.05). In summary, the antioxidant properties of SPF were enhanced under gastrointestinal pH conditions, suggesting that SPF might possess a considerable amount of bound phenolic and other antioxidative compounds. The antioxidant properties of SPF are largely influenced by pH and thus might be enhanced during the in vivo digestive process.
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