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Search Results: 1 - 10 of 461867 matches for " A. Helal "
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The Characteristic Function Method and Its Application to (1 + 1)-Dimensional Dispersive Long Wave Equation  [PDF]
Medhat M. Helal, Mohammad L. Mekky, Emad A. Mohamed
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.31002
Abstract: In this paper, the characteristic function method is applied to seek traveling wave solutions of nonlinear partial differential equations in a unified way. We consider the Wu-Zhang equation (which describes (1 + 1)-dimensional disper-sive long wave). The equations governing the wave propagation consist of a pair of non linear partial differential equations. The characteristic function method reduces the system of nonlinear partial differential equations to a system of nonlinear ordinary differential equations which is solved via the shooting method, coupled with Rungekutta scheme. The results include kink-profile solitary wave solutions, periodic wave solutions and rational solutions. As an illustrative example, the properties of some soliton solutions for Wu-Zhang equation are shown by some figures.
Discourse and Intercultural Academic Rhetoric  [PDF]
Fethi Helal
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.32020
Abstract: This paper is critically concerned with the recent attempts in contrastive rhetoric (CR) to interpret the linguistic and rhetorical differences found in the academic discourses produced by Anglophone and nonAnglophone academic and research writers. Framing this critique within a discourse view of language, culture and communication, this paper points to the need to go beyond such a priori, static, and too often vague concepts as language and culture as explanatory variables in intercultural (academic) rhetoric. Moreover, using data that examined the use of English in lingua franca contexts, the paper urges researchers in CR to consider the differences and misunderstandings arising from a history of socialization of academics to different discourse communities, varying assumptions of what constitutes appropriate academic genres, as well as the identities and meanings that are co-constructed in concrete and situated rhetorical action. It is believed that such a perspective on intercultural academic communication will not only help move the CR agenda forward, but will also lead to a better understanding of communicative and intercultural competence, and dialogue with the cultural academic “other”.
A Similarity Technique for Solving Two-Layer Shallow-Water Equations  [PDF]
Magda M. Kassem, Medhat M. Helal, Mohammad L. Mekky, Emad A. Mohamed
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.34047
Abstract: This paper is devoted to the analysis of the two-layer shallow-water equations representing gravity currents. A similarity technique which is the characteristic function method is applied for this study. The application of the characteristic function method makes it possible to obtain the similarity forms depending on a group of infinitesimal transformations. Thus, the number of independent variables is reduced by one and the governing partial differential equations with the auxiliary conditions reduce to a system of ordinary differential equations with the appropriate auxiliary conditions. Numeric solutions are presented and discussed.
Radiation doses to normal tissues during craniospinal irradiation: Improvement of the dose to the eye and lens, dosimetric study
MF Mostafa, A Helal, MF Noaaman
Alexandria Journal of Medicine , 2011,
Abstract: Introduction: Craniospinal irradiation is a very important element in treating medulloblastoma. Every effort should be made to decrease the radiotherapy related side effects, especially with the currently available 3D conformal radiotherapy planning system. Objective: This dosimetric study is aiming to report the results of the analysis of doses received by target volumes and organs outside the target volumes during the treatment of medulloblastoma patients. And also by comparing the doses reaching the eyes and the lens with the use of different shielding methods. Methodology: Ten children with recent diagnosis of high risk medulloblastoma were included. They were subjected to MRI of the brain and spine together with CSF cytology 3 weeks after surgery. They were subjected to fixation, conventional simulation, followed by CT simulation. The scans will be transferred to the treatment planning system. The brain, spinal canal, and different normal tissue were outlined. For the cranial fields, parallel opposed fields were used with the isocenter of the fields in the midplan in the center of the brain, and behind the eyes. Sensitive tissues close to the target volume were shielded using either MLCS or blocks. The dose prescribed was 36 Gy/20 fractions for cranial and spinal regions. The maximum, minimum, and mean doses to each anatomic structure were computed using dose volume histograms. All patients gave informed consent. Results and conclusion: The dose of radiation received by the target volume and the organs at risk with the use of our new treatment planning system is nearly identical to other studies. The use of block shielding shows lower doses to eyes and lenses regardless of the position of the isocenter, on the other hand, with the use of MLCs for shielding, the isocenter should be behind the eye not in the center of the brain as this shows lower doses to eyes and lenses.
Low Incidence of Contrast Induced Nephropathy after Coronary Angiography in Patients with Advanced Chronic Kidney Disease Treated with Prophylactic Continuous Veno-venous Hemofiltration
A Ghani, N Hussain, B Helal
Arab Journal of Nephrology and Transplantation , 2009,
Abstract: Introduction: Contrast-induced nephropathy (CIN) is associated with increased risk of in-hospital morbidity and mortality. The purpose of this study was to find out whether continuous venovenous hemofiltration (CVVH) after coronary angiography in chronic kidney disease (CKD) patients is associated with a lower incidence of CIN than that reported in the literature. Methods: All patients with CKD who underwent coronary angiography in the Chest Disease Hospital, Kuwait, between January 2004 and December 2005 were treated by CVVH after the procedure. Renal function was assessed before and after the procedure. Results: A total of 98 patients were enrolled in the study, 52 (53.1%) of whom were males. Their mean age was 60.7 years. Before the procedure, the mean serum creatinine level was 4.65 mg/dl and the mean creatinine clearance (Cr Cl) was 18.04 ml/min. Patients underwent CVVH for a mean duration of 21.3 hours, after a mean time-interval of 44.3 min. Their mean serum creatinine was 4.57 mg/dl at discharge (within the first week after the procedure) and 4.78 mg/dl at 15 days after the procedure. Mean Cr Cl was 18.52 ml/min at discharge and 17.62 ml/min at 15 days after the procedure. There was no statistically significant difference between the mean serum creatinine and Cr Cl values before and after the procedure. However, one patient (1.02%) developed CIN and ended on regular hemodialysis. The in-hospital mortality was 0%. Conclusion: Patients with advanced CKD who undergo coronary angiography may be protected from further deterioration in their renal function after exposure to radiological contrast material if the procedure is immediately followed by CVVH. A randomized controlled clinical trial is needed to verify our encouraging results.
Las aguas y los alimentos del río tunecino Hamdoun presentan riesgo de disrupción endocrina
W Mnif,A Pillon,MJ Duchesne,AN Helal
Revista de Toxicología , 2006,
Analysis of Trace Elements in Teeth by ICP-MS: Implications for Caries
Mohamed A. Amr,Abdul Fattah I. Helal
Journal of Physical Science , 2010,
Abstract: Teeth are good indicators of environmental exposure to heavy metals and of nutritional status. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to compare the content of trace elements in primary and permanent teeth. For this purpose, primary teeth were collected from 64 children and 112 permanent teeth were collected from 40- to 60-year-old adults. The data were assessed statistically using t-tests. We found that, in comparison to primary teeth, permanent teeth contained significantly higher concentrations of Na, Mg, Al, Fe, Ni, Cu, Sr, Cd, Ba, Pb and U and significantly lower concentrations of Mn, Co, As, Se, Mo and Bi. In addition, a comparison of the concentrations of trace elements in the pulps of individuals with healthy vs. carious teeth showed that the mean concentrations of Na, Al, Cr, Mn, Co, Cu, Zn, Mo, Ag, Bi and U were lower in those with carious teeth. However, the concentrations of Mg, Cd and Pb in the pulps were higher in individuals with carious teeth than in those with healthy teeth.
The Three Page Guide to the Most Important Results of M. S. El Naschie’s Research in E-Infinity Quantum Physics and Cosmology  [PDF]
M. A. Helal, L. Marek-Crnjac, Ji-Huan He
Open Journal of Microphysics (OJM) , 2013, DOI: 10.4236/ojm.2013.34020

In this short survey, we give a complete list of the most important results obtained by El Naschie’s E-infinity Cantorian space-time theory in the realm of quantum physics and cosmology. Special attention is paid to his recent result on dark energy and revising Einstein’s famous formula .

Letrozole versus Gonadotropin in Unexplained Infertile Couples Failed to Conceive with Clomiphene Citrate  [PDF]
Moustafa Abbas Ibrahaiem, Sherin A. Shazly, Khaled F. Helal, Hala Mowafy, Manal M. El Behery
Open Journal of Obstetrics and Gynecology (OJOG) , 2014, DOI: 10.4236/ojog.2014.410088

Background: Unexplained infertility represents about 15% - 20% of infertile couples. Usually, these cases need assistance. Clomiphene citrate is the most used drug for this problem but sometimes pregnancy failed to achieve it, so other options for assistance are gonadotrophin or letrezole. The objective of our study was to compare the pregnancy rate for letrezole and gonadotropin inunexplained infertile women’s who failed to conceive with clomiphene citrate. Methods: This prospective quasi-randomized trial was carried out in cytogenetic unite at obstetrics and gynecology department, Zagazig University Hospital. 140 infertile females were included, induction of ovulation by letrozole for half of them and by gonadotrophin for the other half. Results: There was statistically highly significant decrease in duration of stimulation, E2 levels and endometrial thickness at day of HCG in letrezole group, no significant difference between two groups as regard number of follicles and pregnancy rate per cycle, while the cumulative pregnancy rate and the cost of stimulation are significantly higher in gonadotrophin group. Conclusion: In patient with unexplained infertility who failed to conceive with clomiphene citrate, gonadotrophins have a higher pregnancy rate than letrezole. However, pregnancy rate was high enough with lower cost with letrezole to be acceptable and justified its use in this group of patients.

UV/O3 Preirradiated Cotton Fabric-Containing Chitosan for Effective Removal of Heavy Metals  [PDF]
A. Hebeish, Kh. Elnagar, M. H. Helal, M. S. Ragab, M. F. Shaaban
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.510071
The present work aims at studying the effect of Ultra-Violet/Ozone (UV/O3) irradiation of cotton fabrics on their interaction with chitosan/citric acid based formulation and, the onset of this on the ability of treated fabrics to remove heavy metal ions from their aqueous solutions. To achieve the goal, the cotton fabrics were preirradiated for 90 minutes using UV/O3 as radiation source. The irradiated and the unirrdadiated cotton fabrics were submitted to finishing formulation consisting essentially of chitosan as a finishing agent and citric acid as crosslinking agent in combination with sodium hypophosphite (SHP) as a catalyst. Finishing formulation containing different concentrations of chitosan (0 - 4) along with citric acid (8 g/l) and SHP (4 g/l) were used and the interaction of chitosan with the cotton fabric was assessed through nitrogen measurement. The preirradiated and chemically finished fabrics vis-à-vis the unirrdadiated fabrics were examined for metal ion removal. Results conclude that the preirradiated cotton fabrics exhibit higher nitrogen content than the unirrdadiated fabrics. The same holds true for heavy metal removal, exemplified by Zn2+ and Cd2+ ions from their aqueous solutions. That is, preirradiated fabrics containing chitosan display higher percent heavy metal removal than their unirrdadiated mates.
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