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Search Results: 1 - 10 of 13612 matches for " Amal El Shahawy "
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Advantage of NMR and FTIR Spectroscopy to Determine Structure Role of CeO2 in Complicated Borosilicate Glasses: New Approach  [PDF]
Gomaa El-Damrawi, Abdelmeguid K. Hassan, Salma Ehmead, Amal El Shahawy
New Journal of Glass and Ceramics (NJGC) , 2017, DOI: 10.4236/njgc.2017.72003
Abstract: Microstructure of complicated glasses in the system 30Na2O-2Al2O3-25 SiO2-xCeO2 (43-x) B2O3, x changes from 0.5 to 20 mol% have been extensively studied. Structural determination of glasses containing high cerium oxide content (≥8 mol% CeO2) was carried out by 11B NMR and FTIR spectroscopy. On the other hand, 29Si MAS NMR experiment is hardly to be applied to glasses of CeO2 > 8 mol%. This is due to the paramagnetic action which is raised by cerium cations causing dilution or delaying in the resonance phenomenon. It is evidenced from NMR data that sodium oxide is high enough to modify the glass forming units which constitute the skeleton of the glass. Ceria is as well as silica and B2O3 all are acting as glass forming species. Decreasing of both fraction of boron tetrahedral units (N4) and chemical shift of silicon nuclei (δ) confirm the role of CeO2 as a glass former. On the other hand, fast decrease in N4 and chemical shift of Si nuclei with further increasing CeO2 contents (≥8 mol%) gives a clear evidence that the ability of cerium oxide to participate as a network former increases with increasing its content. New approach is applied to determine the fraction of CeO4 as a glass forming units. In this approach, we use the common advantage of 11B NMR and FTIR spectroscopy to obtain Ce4 fraction. The latter species cannot be determined from NMR spectroscopy, since very high relaxation time and magnetization of ceria cause intensive spectral broadening which prevent resonance spectra to be appeared.
DFT Cancer Energy Barrier and Spectral Studies of Aspirin, Paracetamol and Some Analogues  [PDF]
Anwar El-Shahawy
Computational Chemistry (CC) , 2014, DOI: 10.4236/cc.2014.21002
Abstract: Comparative DFT computations were studied between Paracetamol (PA) and its analogues such as p-nitroace- tanilide (PA-NO2), p-bromoacetanilide (PA-Br) and N-acetylanthranilic acid (NAA) which can be considered also as analogue of Aspirin (ASP). As well, Thio-Aspirin, Acetyl-Thio-Salicylic acid, (TASP) is another analogue of ASP. From DFT studies, it has been concluded that PA and its analogues have the predominant trans-conformers with respect to directions of the carbonyl group in the acetyl moiety and the amino-hydrogen atom but the predominant conformer of NAA molecule is the cis-form. Phenacetin (PH) molecule which has ethoxy group in the Para-position instead of the hydroxyl group in the Para-position in PA molecule is another analogue of PA. The electron transfer energy between the drugs and the nucleic acid bases can be illustrated as cancer energy barrier. The cancer energy barriers were calculated from the DFT parameters for all the studied molecules showing the carcinogenic effect. The metabolized product N-acetylimidoquinone, m-PA, is produced in the liver from PA and PH. m-PA has higher electron affinity more than those of the nucleic acid bases indicating to the strong electronic withdrawing power from the nucleus in the human being liver cell, hence m-PA is responsible for the carcinogenic behavior of the liver cell since it has low energy barrier with guanine, 0.3 eV. Therefore the electron transfer between m-PA and guanine takes place spontaneously in the liver. From CI calculations it has been concluded that the singlet transition energies for the trans and cis conformers of PA are the same. The comparative spectral studies have been scanned for some analogues in the visible and UV regions using solvents of different polarities. The complex between PA and Zn2+ was studied by DFT method.
DFT-Comparison of Anti-Cancer Effect of Ibuprofen Drug Anions and Breast Cancer Treatment by Ethanolic Solution of Nitrobenzaldehyde in Two Hours  [PDF]
Anwar El-Shahawy
Computational Chemistry (CC) , 2017, DOI: 10.4236/cc.2017.51002
Abstract: Focusing our DFT calculations on the carboxylic acid drugs such as ibuprofen drug (IBF), it has been concluded that the anions of these types of drugs have the spontaneous electron donor character to all the carcinogenic cells of electron deficiency in their nuclei. Due to the spontaneity of electron transfer of anions, it has been found clinically that ibuprofen drug cures cancers of colon, protostate, lung and breast. The breast cancer treatment of Matthew Gdovin group in two hours by injection of ethanolic solution of nitrobenzaldehyde in the breast tumor in presence of uv-irradiation has been studied from TD-DFT point of view; the excited states of these molecules in presence of uv-irradiation act as electron donors to the cancerous cells to compensate the electron deficiency. Finally, it has been concluded that the electron transfer is the main cause of the breast cancer treatment which is the most aggressive type of cancers and is one of the hardest to treat.
Eimeria pavoaegyptica sp. nov. (Apicomplexa: Eimeriidae) in faeces of Indian peacocks, Pavo cristatus Linnaeus, 1758 (Galliformes: Phasianidae) from Egypt
El-Shahawy, Ismail Saad;
Memórias do Instituto Oswaldo Cruz , 2010, DOI: 10.1590/S0074-02762010000800003
Abstract: coprological examination of 15 indian peacocks, pavo cristatus, revealed the presence of a coccidium species of the genus eimeria, which apparently represents a previously undescribed species. sporulation is exogenous and fully developed oocysts of eimeria pavoaegyptica sp. nov. are ellipsoidal, with a dimension of 15 (13-16) × 12 (10-12.9) μm and with a shape index of 1.25 (1-1.3). the sporulated oocysts have no micropyle but enclose one large rectangular-shaped polar granule and an oocyst residuum. the oocysts have a distinct two-layered wall, which is ~1.7 μm thick. the outer layer has a smooth texture; it fills ~? of the total thickness and appears bicolored. the sporocysts are boat-shaped, of about 10 (9-11) × 4 (4-4.7) μm; their average shape-index is 2.5 μm with a small pointed stieda body and a smooth, thin single-layered wall. no substieda body is detected. the sporocysts contain numerous, nearly uniform granular residua. the sporozoites are banana-shaped, 6 × 3 μm and each has two different-sized refractile bodies.
Cigarette use attitudes and effects of acculturation among Arab immigrants in USA: A preliminary study  [PDF]
Linda Haddad, Omar El-Shahawy, Kawkab Shishani, Hala Madanat, Sukaina Alzyoud
Health (Health) , 2012, DOI: 10.4236/health.2012.410122
Abstract: The purpose of this study is to explore cigarette use patterns, which include current use, beliefs, attitudes, attempts to quit, and acculturation, among Arab immigrants. A sample of self-identified Arab immigrants (221) living in the Richmond, VA metropolitan area was recruited from Middle Eastern groceries, restaurants/lounges, and faith and charitable organizations. Men in this sample had higher rates of cigarette smoking (67.6%) than the rest of the general adult US population. Many smokers in the study had the desire to quit and had made attempts to quit. Further analysis of acculturation in relation to the risk of not considering quitting was performed using logistic regression. The older an individual was when he/she moved to the US (OR = 0.93, CI: 0.87, 0.98) and the more time an individual had spent in the US (OR = 0.93, CI: 0.88, 0.98) contributed significantly to the least number of quit attempts. Further random sampling and study is needed to confirm the high prevalence of tobacco use among this minority group.
DFT-Quantum Spectroscopic Studies and Anti-Cancer Effect of Ibuprofen Drug and Some Analogues  [PDF]
Anwar El- Shahawy, Hana Gashlan, Safaa Qusti, Ghada Ezzat, Hossam Emara
Computational Chemistry (CC) , 2016, DOI: 10.4236/cc.2016.42004
Abstract: From our DFT calculations of Ibuprofen drug (IBF) and other related molecules such as 2-Phenylpropanoic acid (2-PPA) and 3-Phenylpropanoic acid (3-PPA), it has been found that the ionization potential energies of their anions are decreased strongly, with respect to their values in the molecular forms, rendering them as spontaneous electron donor which can compensate the electron deficiency for the positive cancer cells. Time dependent calculations show good coincidence with the experimental absorption spectra. Some complexes of IBF are prepared with Cu++ and Zn++ ions. The ratio between the M++ and the ligand (IBF) is 1:2 which has been verified by atomic absorption spectra and elemental analyses. Their spectral studies have been performed in different solvents of different polarities. The metabolite products of IBF have been studied from DFT calculations point of view and it has been concluded that the consistency of the ionization constants and the electron affinities of them with those of the nucleic acid bases prevents the electron transfer between them therefore they are safe for the human body from cancer diseases.
Structural Role of Cerium Oxide in Lead Silicate Glasses and Glass Ceramics  [PDF]
Gomaa El-Damrawi, Amal Behairy
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2018, DOI: 10.4236/jmmce.2018.63031
Abstract: Silicate glasses and glass ceramics in the system CeO2-PbO-SiO2 have been studied as a function of the structure factors R and K. The latter two factors are defined as: R = (CeO2 + PbO)/SiO2 and K = (SiO2/CeO2) molar ratios. In this glass, PbO is fixed at 50 mol% and CeO2 increases at the expense of SiO2. NMR investigations have revealed that increasing R which is accompanied with decreasing K leads to reasonable decrease in the shielding of silicon atoms. The chemical shift (δ) showed an increasing behavior due to increasing non-bridging oxygen atoms (NBO) in silicate network. It is evidenced that NBO in cerium free glass is much lower than that of glasses containing CeO2. Increasing R is clearly leading to higher chemical shift and higher NBO. This reflects that CeO2 has an effective structural role, since it would be consumed in all cases as an intermediate oxide. The main portions from CeO2 and PbO inter as glass modifiers which are consumed to form NBO atoms. A limited portion of CeO2 acts as glass former which consumed to form tetrahedral cerium containing NBO due to modification by PbO as a modifier oxide. Increasing R = [(CeO2 + PbO)/SiO2] from 1 to 2.34 leads to a frequent increase of NBO in the average glass network. FTIR spectroscopy of the glasses showed a clear shift of the main absorbance peak toward the low wavenumber with increasing R which confirms the increasing silicate units containing NBO atoms. XRD of the investigated materials revealed the presence of some nanostructures from cerium silicate crystalline phases. Formation of separated phases containing micro clusters is found to depend on NBO concentration, since NBO can facilitate process of phase separation. Majority of modifier are consumed to form NBO in the glass network and the rest are aggregated or separated to form silicate phase riches with cerium cations. In such case, some of silicon atoms are electrically compensated with both Pb and Ce cations.
Designing and Synthesis of New Fluorine Substituted Pyrimidine-Thion-5-Carbonitriles and the Related Derivatives as Photochemical Probe Agents for Inhibition of Vitiligo Disease  [PDF]
Mohammed S. T. Makki, Dina A. Bakhotmah, Reda M. Abdel-Rahman, Mohammed S. El-Shahawy
International Journal of Organic Chemistry (IJOC) , 2012, DOI: 10.4236/ijoc.2012.223043
Abstract: A new biocidal agents fluorine substituted-3-thioxopyrimidine-5-carbonitriles (2-9) and/or the related fluorine substi- tuted pyrimido (4,5-d) pyrimidines (10-14) were synthesized by the cycloaddition of fluorinated β- arylidine malo- nonitriles (1a-c) followed by a nucleophilic attack against α,β-bifunctional reagents in different conditions. Structures of the fluorine targets were characterized by their elemental analysis and spectral data (UV, IR, 1H NMR, 13C NMR and mass measurements) and further evaluated as photochemical probe for inhibition of Vitiligo, it was found that compounds 5, 9, 11 and 12 exhibited high potency over the investigated compounds.
High Quality of Piezoelectric Response of Nano Ni Doped Pb1-xNixTiO3 Ceramic  [PDF]
A. Tawfik, O. M. Hemeda, D. M. Hemeda, M. Barakat, M. M. El-Shahawy, R. Shady
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.410190
Abstract: A series of Pb1-xNixTiO3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by the general ceramic and co-precipitation method. The grain size decreased with increasing Ni contents. The piezoelectric modulus d33 increased with increasing Ni contents. It was observed also the d33 of the nanocomposite Pb1-xNixTiO3 prepared by co-precipitation method is higher than those of the prepared by general ceramic method. The coupling factor kp increased by the more doping of Ni. The ultrasonic wave velocity decreased also with increasing Ni contents. The polarized nano-sample of composition Pb0.5Ni0.5TiO3 is suitable for improving application of useful piezoelectric technology.
CNDO/SCF molecular orbital structural studies and charge transfer complex formation between 4,4’-dimethoxydiquinone and uracil
Anwar S. El-Shahawy, Ahmed S. Hammam
Bulletin of the Chemical Society of Ethiopia , 2004,
Abstract: Through CNDO/SCF molecular orbital calculations, the structure of 4,4’-dimethoxy- diquinone (DQ) has been discussed and compared with some related compounds. The electron transfer between DQ and uracil was studied in ethanol as an interaction medium. The ionization potentials and the electron affinities of the studied molecules have been calculated in addition to their charge densities giving the columbic potential energy of the donor and acceptor. The experimental charge transfer band lies at 500 nm. The electronic transitions have been calculated for the singlet and triplet transitions in uracil and DQ molecules using the SCF eigenvectors of the two HOMO’s, yn-1 and yn, and the two LUMO’s, yn+1 and yn+2, using CI theory. The calculated electronic transitions are compared with those of the experimental data to verify the non-planar structure of the DQ molecule. KEY WORDS: CNDO/SCF molecular orbital calculations, 4,4’-Dimethoxydiquinone, Uracil, Ionization potentials, Electron affinities Bull. Chem. Soc. Ethiop. 2004, 18(2), 193-204.
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