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Search Results: 1 - 10 of 417488 matches for " El-Hadi M. Ahmed "
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The Effect of Annealing Treatments on Spherulitic Morphology and Physical Ageing on Glass Transition of Poly Lactic Acid (PLLA)  [PDF]
El-Hadi Ahmed Mohamed
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.25058
Abstract: Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The effect of both annealing temperature and crystallization temperature on the formation of cracks was described by polarized optical microscope (POM). Non banded spherulite (fibrils) with cracks was detected in PLLA film after annealing at 160°C (180 min.) and isothermal crystallization temperatures at 140°C and 150°C. With increasing temperature after annealing treatment the size of spherulite is increased and more cracks are formed. The maximum growth rate of spherulites was found at 130°C. The physical ageing was carried out by annealing the PLLA sample at room temperature for several annealing time (ta) from 0 h to 720 h. The enthalpy relaxation has been studied by differential scanning calorimetry (DSC) through analysis of the endothermic peak of glass transition temperature, which increased and shifted towards higher temperature as the annealing time increased.
Antiplasmodial Activity of Some Medicinal Plants Used in Sudanese Folk-medicine
El-Hadi M. Ahmed, Bakri Y.M. Nour, Yousif G. Mohammed and Hassan S. Khalid
Environmental Health Insights , 2012, DOI: 10.4137/EHI.S4108
Abstract: Ten plants indigenous to Sudan and of common use in Sudanese folk-medicine, were examined in vitro for antimalarial activity against schizonts maturation of Plasmodium falciparum, the major human malaria parasite. All plant samples displayed various antiplasmodial activity. Three plant extracts caused 100% inhibition of the parasite growth at concentrations of plant material ≤ 500 ug/ml. The two most active extracts that produced 100% inhibition of the parasite growth at concentration of plant material ≤ 50 μg/ml were obtained from the seeds of Nigella sativa and the whole plant of Aristolochia bracteolata. The ten plants were phytochemically screened for their active constituents. The two most active plants showed the presence of sterols, alkaloids and tannins.
Antiplasmodial Activity of Some Medicinal Plants Used in Sudanese Folk-medicine
El-Hadi M. Ahmed,Bakri Y.M. Nour,Yousif G. Mohammed,Hassan S. Khalid
Environmental Health Insights , 2010,
Abstract: Ten plants indigenous to Sudan and of common use in Sudanese folk-medicine, were examined in vitro for antimalarial activity against schizonts maturation of Plasmodium falciparum, the major human malaria parasite. All plant samples displayed various antiplasmodial activity. Three plant extracts caused 100% inhibition of the parasite growth at concentrations of plant material ≤ 500 ug/ml. The two most active extracts that produced 100% inhibition of the parasite growth at concentration of plant material ≤ 50 μg/ml were obtained from the seeds of Nigella sativa and the whole plant of Aristolochia bracteolata. The ten plants were phytochemically screened for their active constituents. The two most active plants showed the presence of sterols, alkaloids and tannins.
Human epidermal growth factor receptor-2 in oesophageal cancers: An observational study
Hazem Al-Momani,Rachel Barnes,Ahmed El-Hadi,Rachit Shah
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i44.6447
Abstract: AIM: To determine the incidence of human epidermal growth factor receptor 2 (HER2) over expression in oesophageal cancers. METHODS: A retrospective study, of one hundred consecutive cases of endoscopic histological samples of oesophageal cancers from a single British cancer network were included. Cancer cases were diagnosed between April 2007 and June 2010. HER2 over expression was assessed using immunohistochemistry, those that scored “0” and “+1” were considered “negative” for HER2; those that scored “+3” were considered “Positive”. Cases that were scored “+2” on immunohistochemistry further went on to have HER2 gene analysis using the Ventana HER brightfield dual-colour in situ hybridisations (HER B DISH) assay and either came back to be positive or negative for HER2 over expression. Overall survival was measured from date of histological diagnosis until date of death. 93% of the cases were followed up till five years or death, and all were followed up till two years. Cases of gastro-oesophageal junctional tumours were excluded. RESULTS: The median age of our sample was 66 years (range: 38-91 years). Eighty one were male and 19 female. Ninety-one of the cases were adenocarcinoma of the oesophagus and the rest were cases of squamous cell carcinoma. The anatomical distribution of the tumours was; upper oesophagus 2, middle oesophagus 11, and 87 were in the lower oesophagus. Operative resection was completed in 15 cases; seven cases had attempted surgical resections, i.e., open and close, 33 patients received definitive chemo-radiation and 52 had palliative treatment. Twenty-five of the cancers showed evidence of HER2 over expression, all were adenocarcinomas. Of the 25 cases that showed evidence of HER2 over expression, 21 (84%) were located in the lower third of the oesophagus. On staging, 24 out of the 25 HER2 positive cases were at stage 3 or more (13 at stage 3 and 11 at stage 4), For HER2 negative cases 37 were at stage 3 and 32 were staged as stage 4. Seventeen out of twenty five cases (68%) with HER2 over expression received palliative therapy, in comparison to thirty five out of seventy five (46.7%) in tumours not expressing HER2. No significant difference in overall survival was demonstrated between patients whose cancers showed evidence of HER2 over expression and those who did not; median overall survival for HER2 positive tumours was 15 mo (95%CI, 11-19 mo) compared to 13 mo (95%CI, 9-17 mo) for HER2 negative ones. Two years cumulative survival for cases with HER2 over expression was 33.7% compared to 31.6% in cases without HER2 over expres
Plemorphic Adenoma of the Infratemporal Space: A New Case Report
Tarik El-Hadi,A. Oujilal,M. Boulaich,L. Sqalli,M. Kzadri
International Journal of Otolaryngology , 2009, DOI: 10.1155/2009/529350
Abstract: Plemorphic adenoma is a frequent benign tumor of the major salivary glands. It could also develop from accessory salivary glands. We are reporting an extremely rare case of pleomorphic adenoma developing from the infratemporal space. The final diagnosis was based on histological confirmation. The treatment was mainly a complete resection via an anterior transmaxillary approach. Diagnosis, clinical behaviour, and treatment of pleomorphic adenoma of the infra-temporal space are reviewed from the literature.
Fractional power function spaces associated to regular Sturm-Liouville problems
Sofiane El-Hadi Miri
Electronic Journal of Differential Equations , 2005,
Abstract: Using spectral properties of the regular Sturm-Liouville problems, we construct a collection of abstract function spaces. Then we find the smallest index for which these spaces are mapped continuously in to the space of continuous functions. We also give some applications of these spaces for variational methods.
Invasive meningococcal disease epidemiology and control measures: a framework for evaluation
J Jaime Caro, J?rgen M?ller, Denis Getsios, L Coudeville, Wissam El-Hadi, Catherine Chevat, Van Hung Nguyen, Ingrid Caro
BMC Public Health , 2007, DOI: 10.1186/1471-2458-7-130
Abstract: A discrete event simulation of the epidemiology of invasive meningococcal disease was developed to quantify the potential impact of implementing routine vaccination of adolescents in the United States with a quadrivalent conjugate vaccine protecting against serogroups A, C, Y, and W-135. The impact of vaccination is assessed including both the direct effects on individuals vaccinated and the indirect effects resulting from herd immunity. The simulation integrates a variety of epidemiologic and demographic data, with core information on the incidence of invasive meningococcal disease and outbreak frequency derived from data available through the Centers for Disease Control and Prevention. Simulation of the potential indirect benefits of vaccination resulting from herd immunity draw on data from the United Kingdom, where routine vaccination with a conjugate vaccine has been in place for a number of years. Cases of disease are modeled along with their health consequences, as are the occurrence of disease outbreaks.When run without a strategy of routine immunization, the simulation accurately predicts the age-specific incidence of invasive meningococcal disease and the site-specific frequency of outbreaks in the Unite States. 2,807 cases are predicted annually, resulting in over 14,000 potential life years lost due to invasive disease. In base case analyses of routine vaccination, life years lost due to infection are reduced by over 45% (to 7,600) when routinely vaccinating adolescents 12 years of age at 70% coverage. Sensitivity analyses indicate that herd immunity plays an important role when this population is targeted for vaccination. While 1,100 cases are avoided annually when herd immunity effects are included, in the absence of any herd immunity, the number of cases avoided with routine vaccination falls to 380 annually. The duration of vaccine protection also strongly influences results.In the absence of appropriate real world data on outcomes associated with la
Two-Dimensional Fuzzy Spatial Relations: A New Way of Computing and Representation
Nadeem Salamat,El-hadi Zahzah
Advances in Fuzzy Systems , 2012, DOI: 10.1155/2012/167939
Abstract: Fuzziness is found everywhere, in modeling spatial relations, fuzziness is found at object level as well as in relation semantics. Commonly, fuzzy topological relations are computed between fuzzy objects. Fuzziness in relation semantics is represented by fuzzy topological relations between crisp objects and these types of fuzzy topological relations are much less developed. In this paper, we propose a method for combining fuzzy topological and directional relations. We also propose an algorithm for defuzzification of relations which provides us a binary topological and directional relation between a 2D object pair. These relations are represented in a neighborhood graph. For validation and assessment, a number of experiments have been performed on artificial data. 1. Introduction The space can be studied through objects as well as spatial relationship between them. These spatial relations provide information about topological structure, orientation between objects and their relative locations. Topological relations are derived from geometric descriptions. The 9-intersections and region connection calculus (RCC) [1, 2] are well known methods for defining binary topological relations. The 9-intersection method depends on point set topology where topological parts (interior, boundary, and exterior) of an object participate. In this method, topological structure is studied by empty ( ) and nonempty ( ) intersections of topological parts. Eight basic topological configurations between 2D objects in are observed out of 512 possible configurations. Many extensions have been proposed in the 9-intersection method [3–6]. The 9-intersection method is extended to deal with fuzzy objects and 44 useful topological relations were developed with the 9-intersection between objects with extended boundaries [7]. The 9-intersection method is also extended to 16 intersections and a set of 152 useful configurations between fuzzy regions in are observed [8]. The 9-intersection and the 16-intersection method do not represent fuzzy topological relations between crisp objects. On the other hand, the RCC method provides information about the topological structure of an image corresponding to eight basic topological relations in two-dimensional space. The RCC method is applied to regular topological spaces and this calculus is based on the axiomatic theory in which regions are primitives [9]. In this theory, spatial relations are based on a connection relation . This calculus is extended to fuzzy theory and fuzzy topological relations are developed between fuzzy objects [10–12]
Immobilization of Mucor racemosus NRRL 3631 Lipase with Different Polymer Carriers Produced by Radiation Polymerization
Mostafa, H.,El-Hadi, A. A.
Malaysian Journal of Microbiology , 2010,
Abstract: Lipase was partially purified from the culture supernatant of Mucor racemosus NRRL 3631. In an attempt to increase the enzyme stability, the enzyme was immobilized on poly (vinyl alcohol) PVA, radiation cross liked poly (vinyl alcohol/ vinyl pyrrolidone) PVA / PVP and poly (vinyl alcohol/ hydroxyethylmethacrylate) PVA/ HEMA hydrogels. The maximum immobilization yield (31.74 %) was obtained using PVA/ HEMA copolymer. The effect of the immobilization parameters on the enzyme such as the hydrogel composition, irradiation dose and the immobilization technique was performed. An optimum radiation dose of 15 kGy and hydrogel composition of 10 % PVA/ HEMA (9.6: 0.4 v/v) increased the immobilization yield to 60.3 %. Diffusion phenomena can be markedly increased the enzyme immobilization on the surface of the hydrogel. In this case the retained activity was approximately 81.5 % of that of the free enzyme. The profiles of immobilized enzyme activities at various pH values (4-9) and temperatures (30-80 °C) showed an overall higher stability for the immobilized enzyme than that for the free one. The half life values of the immobilized and free enzymes at 60 °C were 3.3 h and 1.73 h, respectively. The immobilized enzyme retained 69.2 % of its initial activity after three cycles.
Spatiotemporal Relations and Modeling Motion Classes by Combined Topological and Directional Relations Method
Nadeem Salamat,El-hadi Zahzah
ISRN Machine Vision , 2012, DOI: 10.5402/2012/872687
Abstract:
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