Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2018 ( 1 )

2016 ( 1 )

2015 ( 2 )

2014 ( 14 )

Custom range...

Search Results: 1 - 10 of 94 matches for " Usama Elewa "
All listed articles are free for downloading (OA Articles)
Page 1 /94
Display every page Item
Bisphenol A in Chronic Kidney Disease
Emilio González-Parra,Jose Antonio Herrero,Usama Elewa,Ricardo J. Bosch,Alberto Ortiz Arduán,Jesus Egido
International Journal of Nephrology , 2013, DOI: 10.1155/2013/437857
Abstract: Phenols are uremic toxins of intestinal origin formed by bacteria during protein metabolism. Of these molecules, p-cresol is the most studied and has been associated with renal function impairment and vascular damage. Bisphenol A (BPA) is a molecule with structural similarity with phenols found in plastic food and beverage containers as well as in some dialyzers. BPA is considered an environmental toxicant based on animal and cell culture studies. Japanese authorities recently banned BPA use in baby bottles based on observational association studies in newborns. BPA is excreted in urine and uremic patients present higher serum levels, but there is insufficient evidence to set cut-off levels or to link BPA to any harmful effect in CKD. However, the renal elimination and potential exposure during dialysis warrant the monitoring of BPA exposure and the design of observational studies in which the potential health risks of BPA for end-stage renal disease patients are evaluated. 1. Uremic Toxins Multiple molecules accumulate in chronic kidney disease (CKD), are responsible for uremic symptoms, and contribute to increased mortality (uremic toxins). Removal of uremic toxins therefore is accompanied by an improvement in the clinical situation. The term of uremic toxin was created by Piorry in 1847 to indicate the “blood contamination with urine” to refer to the signs and symptoms resulting from kidney disease that increase mortality. Bergstrom [1] proposed that a uremic toxin should be defined as one molecule that meets the following premises:(1)the chemical identity and concentration in biological fluids should be known,(2)the concentration in uremic individuals should be higher than in nonuremic subjects,(3)the concentration should correlate with uremic symptoms, and symptoms should disappear by decreasing the concentration. Uremic toxins have been classified according to size [2]. Over 350 small uremic toxins have been described with a molecular weight below 500?Da [3]. Medium-sized molecules have a molecular weight between 500 and 5000?Da. Many uremic toxins are bound to proteins which hamper their clearance. Uremic toxins are responsible for uremic disease. Among the changes that have been directly related to uremic toxins we find progressive loss of renal function, cardiovascular morbidity, and uremic symptoms such as anorexia, vomiting, weakness, sleep disturbances, and neuropathy. The origin of uremic toxins is multiple. Most uremic toxins originate from the endogenous cellular metabolism. However, there is a growing list of uremic toxins originated in
Hydrogeochemical Attributes and GIS Spatial Modeling in Determining Areas for Horizontal Expansion of Development Projects in East Uweinat, Egypt
H.H. Elewa
Journal of Applied Sciences , 2012,
Abstract: East Uweinat is an important reclaimed area at the southern part of Western Desert of Egypt. The Nubian Sandstone Aquifer System (NSAS) is the sole water source used for all purposes for the last three decades. Determining the priority areas available for horizontal expansion of development projects, depending on the hydrogeological characteristics of the NSAS, has become an essential task. The potentiometric maps of 1990s and 2008 indicated balanced levels in 1980 and 1990s, followed by an accelerated decline from 1990s to 2008. The selected hydrogeochemical attributes represented by the depth to water, aquifer saturated thickness, total dissolved solids and sodium adsorption ratio were integrated to perform a binary-weighted spatial suitability modeling (BSSM-WSSM) techniques to determine the priority areas for development and areas suitable for further horizontal expansion. The BSSM model pinpointed to a minor 1st priority area (1,041 km2) that occurs mostly in the intensively developed area which are characterized by groundwater heavy consumption and a major 2nd priority area (19,381 km2) which refers to a lower quality of the aquifer in terms of the given prioritization criteria. The WSSM identified three more priority classes subdivided from the 2nd priority class, namely, the 2nd (7,793 km2), 3rd (9,976 km2) and 4th (1,622 km2) priority subclasses. These priority subclasses represent the possible areas for development that are located to the N-S-SW parts of the study area. The distribution of aquifer transmissivity (T) and hydraulic conductivity (K) values gave high credibility to the results of the BSSM-WSSM model results.
Influence of Solar Cycle Variations on Solar Spectral Radiation  [PDF]
Usama Ali Rahoma, Rabab Helal
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.31007

The climatic changes associated with solar variability are largely caused by variations in total solar irradiance and solar spectral irradiance with solar activity. Thus the spectral composition of solar radiation is crucial in determining atomspheric structure. The variations in solar spectrum depend on the varied solar spots. Recently, evidence for a strong effect of solar activity on terrestrial isolation on ground-based measurements carried out by the National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Egypt (lat. 29?52'N and long. 31?20'E) during (1990-2000) were presented. Specifically, a strong increase of terrestrial isolation with sunspot number as well as a decline of the solar spectrum with solar activity was reported. Daily measurements of the solar radiation between 280 nm and 2800 nm were made by Eppley Pyranometer and Pyrheliometer instruments. The decreasing at the range 280 - 530 nm and 530 - 630 nm are represented less than 50% of direct solar radiation and the stability of at the range 630 - 695 nm and 695 - 2800 nm it mean that; some of difference radiation is appear in diffused radiation which allow to height of the temperature as much as the largest associated with significance as it appears from the curves of relative humidity.

Production of alkaline protease by Teredinobacter turnirae cells immobilized in Ca-alginate beads
Usama Beshay
African Journal of Biotechnology , 2003,
Abstract: The conditions for immobilizing the new alkaline protease-producing bacteria strain Teredinobacter turnirae by entrapment in calcium alginate gel were investigated. The influence of alginate concentration (20, 25 and 30 g/l) and initial cell loading (ICL) on enzyme production were studied. The production of alkaline protease improved significantly with increasing alginate concentration and reached a maximum enzyme yield of 8000 U/ml at 25 g/l alginate concentration. This was about 176.8% higher than that obtained by free cells (2890 U/ml). The immobilized cells produced alkaline protease consistently over 5 repeated cycles and reached a maximal value of 9000 U/ml on the third cycle. This was 311.4% (3.11-fold) as compared with the control (free cells). Simple mass balance analysis was applied to describe the growth and the protease production behaviour of both fractions the cells in free form and the entrapped in Ca-alginate beads. Scanning electron microscope studies indicated the internal distribution pattern of the cells encapsulated in Ca-alginate beads. The results presented in this paper show the potential for using immobilized T. turnirae cells in Ca-alginate for the production of a novel alkaline protease. (African Journal of Biotechnology: 2003 2(3): 60-65)
Coronary artery ectasia and atrial electrical and mechanical dysfunction
Usama Boles
Anadolu Kardiyoloji Dergisi , 2012,
Kidney Transplantation in Iraq
Rifat Usama
Saudi Journal of Kidney Diseases and Transplantation , 2006,
Principles of Green Urbanism: the Absent Value in Cairo, Egypt
Usama Nassar
International Journal of Social Science and Humanity , 2013, DOI: 10.7763/ijssh.2013.v3.258
Abstract: Cairo is considered one of the main growing cities in the Arab world today. Conventional planning has failed to direct this growth towards creating sustainable urban environments for all, and has instead encouraged lopsided development that caters only to the affluent sections. This trend has affected public urban spaces as well, which are now centered on consumption and dependant on heavy investment in real estate and technology. This has a considerable impact on the spectrum of socio-economic groups that are able to access and use them. Taking as a starting point the principles and concept of Green Urbanism, the paper questions the prevalent situation, and focuses on three aspects that have been ignored in recent approaches in recent development plans. The first (Green Urbanism) is explored as a main principles to revitalize the second (Public Spaces), in order to achieve the third (Sustainable Model) as a long term goal. This is done using analysis and design in parallel, and results in a proposal for a new design process and through it, scale specific design solutions for Cairo public spaces that will create a high quality of life for the people of the heavily populated, demographically diverse and socio-economically fragmented city.
Space periodic Jacobi elliptic solution for triad modified Schr?dinger equations
Usama Kadri
Physics , 2014,
Abstract: We present an analytical solution for triad nonlinear evolution equations with modified Schr\"odinger terms. An example for application in compressible water waves is presented.
Economic Evaluation of Conventional Radiography with Film and Computed Radiography: Applied at BMC  [PDF]
Usama Ali Rahoma, Pavan Kumar Chundi
Advances in Computed Tomography (ACT) , 2012, DOI: 10.4236/act.2012.13006

Conventional radiography with film (CRF) has been in use for diagnostic purposes for a long time now. It has proved to be a great assert for the radiographers in assessing various abnormalities. With recent advances in technology it is now possible to have digital solutions for radiography problems at a very cost effective, environment friendly and also with better image quality in certain applications when compared to CRF. Rather than using a CRF a computed radiography (CR) uses imaging plates to capture the image. The imaging plate contains photosensitive phosphors which contain the latent image. Later this plate is introduced into a reader which is then converted into a digital image. The major advantage and the cost effective element of this system is the ability to reuse the imaging plates unlike the photographic film where in only a single image can be captured and cannot be reused. The computed radiography drastically reduces the cost by eliminating the use of chemicals like film developers and fixers and also the need for a storage room. It also helps to reduce the costs that are involved in the disposal of wastes due to conventional radiography. This paper investigates whether it is cost effective to use computed radiography over film based system at Al-Batnan Medical Center (BMC), Tobruk, Libya by using Cost Benefit Analysis (CBA). Apart from the initial cost of the CR System, based on the data collected from the center, from the year 2008 to 2012 (until June 2012) a total of 581,566 images were produced with the total cost incurred using film based system being USD 4,652,528. If the same number of images were produced using a CR system the total cost incurred would have been USD 82,600. Taking into consideration the cost of a new CR system to be USD 120,000 the overall cost of producing these images is USD 202,600. It is observed that an amount of USD 4,449,928 could have been saved over the period of 5 years starting from 2008 to 2012 by using the CR system at BMC. Using Cost Benefit Analysis, the average value of the net difference between the costs and benefits for the conventional film based system is ?83.38 where as for the Computed System it is 22.06. Based on the principles of

Evaluation of Lead Hepatotoxicity; Histological, Histochemical and Ultrastructural Study  [PDF]
Ahmed M. S. Hegazy, Usama A. Fouad
Forensic Medicine and Anatomy Research (FMAR) , 2014, DOI: 10.4236/fmar.2014.23013
Abstract: Lead is one of the most well-known naturally occurring environmental heavy metals. This experimental study was designed to evaluate lead induced toxic effects on hepatocytes and lobular architecture as judged microscopically. Material and Methods: This study was conducted in anatomy department, Benha faculty of medicine, Benha University, Egypt from May to October 2013 on 30 normal adult albino rats divided into 3 groups; one control and 2 experimental groups. The experimental groups were given 0.13% lead acetate solution in drinking water for 4 and 8 weeks, respectively. Animals were scarified and livers were removed and used to identify microscopic changes. Specimens were stained with Hematoxylin and eosin, with Masson trichrome stain for study of fibrous tissue and with periodic acid shiff's (PAS) to study the glycogen content. Other specimens were prepared for ultrastructural study. Results: Mild lymphocytic infiltration, vacuolar degeneration and mild increase of periportal fibrosis with mild depletion of glycogen content and partial disappearance of glycogen vacuoles were reported in animals received contaminated water for 4 weeks. Animals maintained for 8 weeks on contaminated water showed hepatic changes in the form of abundant lymphocytic infiltration, increased cellular polymorphism, pyknotic nuclei and areas of cell necrosis with evident moderate periportal fibrosis and marked vacuolar degeneration associated with marked depletion of glycogen content. Ultrastructural study revealed mitochondrial edema, appearance of interstitial inflammatory cells, and appearance of scattered variable sized lead electron-dense inclusion bodies. Conclusion: It could be concluded that chronic exposure to lead imposes a potent toxic effect on liver cells manifested as glycogen depletion, cellular infiltration and liver architecture in the form of initiation of periportal fibrosis that may progress to liver cirrhosis.
Page 1 /94
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.