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Search Results: 1 - 10 of 518 matches for " Rafat Zaki "
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Land Use and Land Cover Changes in Arid Region: The Case New Urbanized Zone, Northeast Cairo, Egypt  [PDF]
Rafat Zaki, Abotalib Zaki, Saad Ahmed
Journal of Geographic Information System (JGIS) , 2011, DOI: 10.4236/jgis.2011.33015
Abstract: The spatial characteristics of land cover are useful for understanding the various impacts of human activity on the overall ecological conditions of the urban environment. The multi-temporal Landsat images (TM) between the years of 1990 and 2003 were used together with the Geographic Information System (GIS) techniques to evaluate the environmental changes in the area around Gabal El Hamza and the surrounding urban expansion in the new urban cities at the northeast side of the Greater Cairo by using the post classification change detection technique and field investigation. Five major units were determined including: urban, cultivated land, Holocene sand dunes, Oligocene basalt and Miocene–Pleistocene sediments. The cultivated cover changed from 89.6 to 150.4 km2 for the years of 1990 and 2003 respectively. The urban area increased from 49.5 to 120.9 km2 with a great value of change reached 71.3 km2 . The basaltic exposures changed from 3 to 3.75 km2 . The sandy cover decreased from 68.9 to 60.1 km2 and the exposures of the rock units changed from 904.8 to 780.8 km2 with removing 124 km2 in 13 years. The total accuracy of the Landsat-derived land cover data was 95 and 92% for the years 1990 and 2003 respectively. Landsat TM thermal infrared data indicated that the surface temperature was strongly affected by the land cover changes.
Impact of Surface Water and Groundwater Pollutions on Irrigated Soil, El Minia Province, Northern Upper Egypt  [PDF]
Rafat Zaki, Esam A. Ismail, Wagih S. Mohamed, Ali Kamel Ali
Journal of Water Resource and Protection (JWARP) , 2015, DOI: 10.4236/jwarp.2015.717120
Abstract: Current research has been focused on heavy metals pollution in surface water and groundwater and effect on irrigated soil from El Minia Province, north Upper Egypt. Concentration of heavy metals (e.g., As, Co, Hg, Ni, Se, Cd and Cr) in surface water, groundwater and irrigated soil samples is most significantly affected by leachate of many pollutants as the factories, agricultural activities, urban and natural processes. Microbiological parameters and microscopic investigations are revealed that some localities are common by micro-organisms, which are unsuitable for drinking waters.
Design and Synthesis of Novel Antimicrobial Acyclic and Heterocyclic Dyes and Their Precursors for Dyeing and/or Textile Finishing Based on 2-N-Acylamino-4,5,6,7-tetrahydro-benzo[b]thiophene Systems
Hoda Zaki Shams,Rafat Milad Mohareb,Maher Helmy Helal,Amira El-Sayed Mahmoud
Molecules , 2011, DOI: 10.3390/molecules16086271
Abstract: A series of novel polyfunctionalized acyclic and heterocyclic dye precursors and their respective azo (hydrazone) counterpart dyes and dye precursors based on conjugate enaminones and/or enaminonitrile moieties were synthesized. The dyes and their precursors are based on 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide, 2-ethoxycarbonyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide or 2-phenylcarbamoyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide systems as precursors. The latter compounds were used to synthesize polyfunctional thiophene-, thiazole-, pyrazole, pyridine-, pyrimidine-, oxazine-, as well as acyclic moieties. The dyes and dye precursors were characterized by elemental analysis and spectral methods. All dyes and their precursors were screened in vitro and evaluated for both their antibacterial and antifungal activities. MIC data of the novel dye systems and their respective precursors showed significant antimicrobial activity against most tested organisms. Some compounds exhibited comparable or even higher efficiency than selected standards. Dyes were applied at 5% depth for disperse dyeing of nylon, acetate and polyester fabrics. Their spectral characteristics and fastness properties were measured and evaluated.
Transmission of human hepatitis C virus from patients in secondary cells for long term culture
Dennis Revie, Ravi S Braich, David Bayles, Nickolas Chelyapov, Rafat Khan, Cheryl Geer, Richard Reisman, Ann S Kelley, John G Prichard, S Zaki Salahuddin
Virology Journal , 2005, DOI: 10.1186/1743-422x-2-37
Abstract: The global public health impact of chronic HCV infection and consequent liver disease continues to grow in numbers. It has been estimated that there are over 170 million carriers of HCV worldwide, with an increasing incidence of new infections [1]. In the United States, an estimated 1% to 5% of the 2.7 million individuals that are currently chronically infected will die due to the HCV infection [2].Although HCV has proven to be very difficult to grow in vitro, HCV-RNA has been detected in cell cultures of a variety of cell types, the presence of positive-strand HCV-RNA persists for periods ranging from a few days to several months, albeit with no evidence of infectious virus [3-6]. The recent creation of HCV-RNA replicons has contributed to a better understanding of some of the molecular events, particularly gene expression [7-9]. However, studies using parts of a virus can only give limited insights about the infectious process and pathogenesis of a specific genotype. For the development of effective rational therapies and the production of protective vaccines, a reproducible in vitro system for the isolation and replication of HCV from patients is critical.We report here that the isolation and long-term replication of HCV in vitro. Since this is the first experience with actively replicating HCV in vitro, some of the results shown here may not fit the current concepts using systems that do not replicate infectious virus.HCV infected patient serum (minimum of 104 genome equivalents/ml) was filtered through 0.45 μ filters (Fisher Scientific) and frozen in 1 ml aliquots at -70°C. A fresh vial of frozen serum was used for every new transmission experiment. The cells were infected using 500 μl of thawed donor serum [10,11].Macrophages were generated from human cord blood mononuclear cells (CBMCs) by treating with Phorbol-12-myristate-13-acetate (PMA, 5 ng/ml in complete medium) [12]. A majority of the cells that adhered to the plastic were positive for non-specific est
Revista de Relaciones Internacionales, Estrategia y Seguridad , 2012,
Abstract: the resumption of the british protectorate in mosquitia, has been normally related with imperialist considerations, and, in parallel, to the possession of a zone where it was planned to build an inter-oceanic channel through nicaragua. in reality, these thesis pose serious difficulties to understand the origin and evolution of the mosquitia issue, as they disregard, a priori, other types of factors that, among other things, end up undermining the imperialistic vision; a number of historic and civilization related factors, without doubt, but also strategic and commercial, made great britain to revive the practice of the mosquitia protectorate.
Revista de Relaciones Internacionales, Estrategia y Seguridad , 2012,
Abstract: in the long sustained diplomatic dispute over the sovereignty of the mosquito coast between the states involved, stands the line of conduct of chancery of new granada, seeking to defend its independence and territorial integrity in this strip of coast, using arguments and titles ambiguous.
Revista de Relaciones Internacionales, Estrategia y Seguridad , 2011,
Abstract: in this article we will see that the contemporary international system is characterized by a set of power relations that approximates the model of unipolar hegemony in its descent phase and the model of classical balance of power on the rise. while acknowledging a growing global interdependence, the fundamental interests still collide and lives on an strategic competition for survival and accumulation of power.
Revista de Relaciones Internacionales, Estrategia y Seguridad , 2010,
Abstract: this article examines the myth of santander in the history books of the first half of the twentieth century, as the stereotype of tradition, national identity and the archetype of a special man, with the individual and collective qualities proper of the national soul. this task would be implemented by the colombian academy of history, which along with the national government, during the period 1910-1962 undertook the task of normalize and give him an autonomous and enduring life.
Wear Resistance of High-Volume Fly Ash Concrete
Leonardo Journal of Sciences , 2010,
Abstract: Wear resistance of high-volume fly ash concrete (HVFA) intended for pavement applications is presented in this paper. In India, yearly production of fly ash is more than 100 million tons. Majority of fly ash is of Class F type. Out of which 20-25% is being utilized in cement-based materials. In order to increase its percentage utilization, an investigation was carried out for its large scale utilization. Concrete mixtures were prepared by replacing cement with 40, 50, and 60% of fly ash. Experiments were conducted for fresh concrete properties, compressive strength and wear resistance. Test results indicated that wear resistance of concrete having cement replacement up to 40% was comparable to the normal concrete. Beyond 40% fly ash content, concretes exhibited slightly lower resistance to wear in relation non-fly ash concretes. There is very good correlation between wear resistance and compressive strength (R2 value between 0.8482 and 0.9787) depending upon age.
Fracture Toughness and Impact Strength of High-Volume Class-F Fly Ash Concrete Reinforced with Natural San Fibres
Leonardo Electronic Journal of Practices and Technologies , 2008,
Abstract: Results of experimental investigation carried out to study the effects of addition of natural san fibres on the fracture toughness and impact strength of high-volume fly ash concrete are presented in this paper. San fibres belong to the category of ‘Natural Bast Fibres’, also known as ‘Sunn Hemp’. Its scientific (botanical) name is Crotalaria Juncea. It is mostly grown in the Indian Sub-Continent, Brazil, Eastern and Southern Africa, and in some parts of the U.S.A. Initially, a control mixture without fly ash was designed. Then, cement was replaced with three percentages (30, 40 and 50%) of low-calcium (Class F) fly ash. Three percentages of san fibres (0.30, 0.60 and 0.90%), having 25 mm length, were used. Tests were performed for compressive strength, fracture toughness, and impact strength at the ages of 28 and 91 days.The test results indicated that the replacement of cement with fly ash decreased the compressive strength and fracture toughness, and had no significant effect on the impact strength of plain (control) concrete. Addition of san fibres did not affect significantly the compressive strength, increased the fracture toughness and impact strength of high-volume fly ash concrete as the percentage of fibres increased.
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