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Search Results: 1 - 10 of 2896 matches for " Marwa Ismail "
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Effect of Nd:YAG laser irradiation on the characteristics of porous silicon photodetector
Raid A Ismail and Marwa K Abood
International Nano Letters , 2013, DOI: 10.1186/2228-5326-3-11
Abstract: Electrical and photoresponse properties of a Al/porous silicon/crystalline silicon/Al structure (Al/PSi/Si/Al) are investigated under irradiation of Nd:YAG laser pulses. The effect of Nd-YAG laser irradiation on the morphological and structural properties of a porous silicon layer is also demonstrated. The porous Si layer is synthesized on a single crystalline p-type Si using electrochemical etching in aqueous hydrofluoric acid at a current density of 20 mA/cm2 for a 40-min etching time. The structure of the porous layer is investigated using atomic force microscopy and optical microscopy. The electrical properties and photodetector figures of merit (responsivity, detectivity, and carrier lifetime) are found to be dependent on the laser fluence.
Feasibility of Upfront Debulking Surgery versus Neoadjuvant Chemotherapy Followed by Interval Debulking Surgery for Advanced Ovarian Cancer  [PDF]
Amen Hamdy Zaky, Adel Gabr, Doaa Wadie Maximous, Ahmed A. S. Salem, Amr Farouk Mourad, Haisam Atta, Marwa Ismail
Journal of Cancer Therapy (JCT) , 2018, DOI: 10.4236/jct.2018.92015
Abstract: Background: Inappropriately ovarian cancer cannot be detected until an advanced stage. Radical debulking surgery is considered the cornerstone in the management of advanced ovarian cancer pointing to complete tumor resolution. Unless optimal debulking cannot be achieved, these patients gain little benefit from surgery. Neoadjuvant chemotherapy (NACT) has been recommended as a novel therapeutic modality to a diversity of malignant tumors when the disease is not willing to optimal surgical resection at the time of diagnosis or the patient who unfit for aggressive debulking surgery. The purpose of this study is to compare survival in the patient with advanced ovarian cancer (stage III/IV) underwent primary debulking surgery followed by adjuvant chemotherapy (PDS-ACTR) to those who received neoadjuvant chemotherapy followed by interval debulking surgery (NACT-IDS). Results: Neoadjuvant chemotherapy (NACT-IDS) showed significant complete cytoreduction and decreased in surgical morbidity in comparison to primary debulking surgery (PDS-ACTR). NACT-IDS showed significant improvement in progression-free survival (P-value 0.002) and overall survival (P-value 0.03) in comparison to PDS-ACTR. Response to NACT and residual volume were the two independent prognostic factors for overall survival. Conclusion: NACT-IDS for advanced ovarian cancer (III/IV) resulted in higher frequency of
Helicobacter pylori genotypes identified in gastric biopsy specimens from Jordanian patients
Laila F Nimri, Ismail Matalka, Kamal E Bani-Hani, Marwa Ibrahim
BMC Gastroenterology , 2006, DOI: 10.1186/1471-230x-6-27
Abstract: Upper endoscopy was performed on 250 patients with symptoms of gastrointestinal diseases. Multiple gastric biopsy specimens were taken from the antrum. All the biopsies were tested by PCR for the H. pylori virulence genes vacA, cagA, and iceA, and 151 were tested by histology.The biopsies positive for H. pylori by PCR were 110/250 (44%), and by histology 117/151 (77.5%), and these results were highly associated (P < 0.02). Analyses of virulence genes revealed that iceA2 (73.6%) was the predominant genotype, the vacAs2 allele was more frequently identified than the vacAs1 allele, while the cagA genotype was low (26.4%). The presence of certain genotypes might be associated with each other, but the presence of certain genotypes was not significantly associated with the age, or gender of the patient.The results illustrate the geographic nature of the genetic diversity of H. pylori, as the identified genotypes are similar to those reported in neighboring countries. This study provides a baseline data of H. pylori genotypes identified in gastric biopsy specimens from Jordan, serving as a powerful epidemiological tool for prospective investigations to better understand the genetic diversity of this pathogen.Helicobacter pylori is a gastric pathogen that chronically infects more than half of all people worldwide. In developing countries, 70–90% of the population carries H. pylori; almost all of these acquire the infection before the age of 10 years [1]. In developed countries, the prevalence is lower, ranging from 25 to 50% (8) [1], due to the improved socioeconomic conditions over the last few decades [2]. Therefore H. pylori infection in developing countries may contribute to childhood malnutrition and increase the risk or severity of infection by other gastrointestinal pathogens such as Vibrio cholerae [3]. Most infected individuals are asymptomatic or have chronic gastritis [1,4]. The differences in disease outcome may be the result of a number of factors that include;
Effects of y-Irradiation and Ageing on Surface and Catalytic Properties of Nano-sized CuO/MgO System
Sahar A. El-Molla,Sahar A. Ismail,Marwa M. Ibrahim
Revista de la Sociedad Química de México , 2011,
Abstract: El sistema de 0.2 Cu/MgO preparado por el método de impregnación fue calcinado a 350 y 450 oC. El efecto de la irradiación y (0.2-1.6 MGy) en su estructura, superficie y propiedades catalíticas, fue investigado utilizando XRD; la adsorción de N2 a -196 oC y la conversión catalítica de isopropanol a 150-275 oC fue determinada utilizando una técnica de flujo. Los resultados revelaron que los sólidos investigados consistieron de nano MgO como fase predominante, además de CuO y trazas de Cu2O. La radiación y de los sólidos investigados ejercen cambios medibles en su superficie y las propiedades catalíticas dependen de la temperatura de calcinación y de la dosis de radiación.El catalizador estudiado actúa como un sólido de deshidrogenación activo. Los 5 a os de envejecimiento de los diferentes sólidos mostraron cambios muy limitados en su superficie y en las propiedades catalíticas indicando una buena estabilidad catalítica de los sólidos preparados e irradiados.
Synthesis, structure characterization and biological evaluation of new 6,8-dichloro-2-methyl-4H-chromen-4-one derivatives
Marwa Sayed Salem,Magda Ismail Marzouk,Salma Nasser Ali,Hassan Mohamed Fawzy Madkour
European Journal of Chemistry , 2012, DOI: 10.5155/eurjchem.3.2.220-227.592
Abstract: The typical active methyl functionality of 6,8-dichloro-2-methyl-4H-chromen-4-one is utilized to obtain 2-styrylchromones, pyruvate ester and phthalide via reactions with aromatic carboxaldehydes, diethyl oxalate and phthalic anhydride respectively. The phthalide provides illustrative example to convert a heterocyclic compound to an aliphatic one via the effect of alcoholic sodium methoxide. Bromination and cycloaddition reactions of 2-styrylchromones afford vicinal dibromide and adducts respectively. This work presents to the art a typical example of heterocyclic systems transformations through the conversion of the starting chromone to coumarin under the influence of thionyl chloride followed by aqueous potassium hydroxide. Some heterocyclic systems like pyrazole, isoxazol and quinolinone are obtained from the target chromone by treatment with hydrazines, hydroxylamine hydrochloride and ammonium acetate respectively. Thiation of starting chromone interestingly affords a dithiated product instead of the expected monothiated one. Antibacterial and antifungal activities of some synthesized compounds have been screened.
Simultaneous determination of miconazole and hydrocortisone or mometasone using reversed phase liquid chromatography
Ramzia Ismail El-Bagary,Ehab Farouk Elkady,Marwa Hosny Tammam,Ayman Abo Elmaaty
European Journal of Chemistry , 2012, DOI: 10.5155/eurjchem.3.4.421-425.667
Abstract: Two simple, rapid and precise reversed phase liquid chromatographic methods have been developed and validated for the simultaneous determination of miconazole nitrate in two binary mixtures, with hydrocortisone acetate (Mixture 1) and mometasone furoate (Mixture 2). For the two mixtures, chromatographic separation was carried out on a C18 column. For mixture 1, a mobile phase consisting of 2.22 mM sodium dihydrogen phosphate (Triethylamine 0.2%):acetonitrile (45:55, v:v) at a flow rate of 0.9 mL/min was used at ambient temperature. Quantitative determination of miconazole and hydrocortisone was achieved with UV detection at 215 and 245 nm, respectively. Linearity, accuracy and precision were found to be acceptable over the concentration range of 30-80 μg/mL for miconazole and 4-80 μg/mL for hydrocotisone. For mixture 2, a mobile phase consisting of acetonitrile:water (Triethylamine 0.2%) (70:30, v:v) at a flow rate of 0.9 mL/min was used at ambient temperature. Quantitative determinations of miconazole and mometasone were achieved with UV detection at 215 and 250 nm, respectively. Linearity, accuracy and precision were found to be acceptable over the concentration range of 10-200 μg/mL for miconazole and 2-60 μg/mL for mometasone. The optimized methods were proved to be specific, robust and accurate for the quality control of the cited drugs in pharmaceutical preparations.
Fully Distributed Tunable Bandpass Filter Based on Thin-Film Slow-Wave Structure
Sébastien L. Delprat,JaeHo Oh,Feng Xu,Lin Li,Erick E. Djoumessi,Marwa Ismail,Mohamed Chaker,Ke Wu
International Journal of Microwave Science and Technology , 2011, DOI: 10.1155/2011/468074
Abstract: This paper presents simulation and measurement results of fully distributed tunable coplanar bandpass filters (BPFs) with center frequencies around 6?GHz that make use of ferroelectric Barium Strontium Titanate (BaxSr1?xTiO3 or BST-x) thin film as tunable material. The two experimental bandpass filters tested are based on a novel frequency-agile structure composed of cascaded half wavelength slow-wave resonators (2 poles) and three coupled interdigital capacitors (IDCs) optimized for bias voltage application. Devices with gap dimensions of 10 and 3?μm are designed and fabricated with a two-step process on polycrystalline Ba0.5Sr0.5TiO3 thin films deposited on alumina substrate. A frequency tunability of 9% is obtained for the 10?μm gap structure at ±30?V with 7?dB insertion loss (the BST dielectric tunability being 26% with 0.04 loss tangent for this gap size). When the structure gap is reduced to 3?μm the center frequency shifts with a constant 9?dB insertion loss from 6.95?GHz at 0?V to 9.05?GHz at ±30?V, thus yielding a filter tunability of 30% (the BST dielectric tunability being 60% with 0.04 loss tangent for this gap size), a performance comparable to some extent to localized or lumped element BPFs operating at microwave frequency (>2?GHz). 1. Introduction The next generation of wireless networks such as reconfigurable and cognitive radio systems will require low-cost and highly integrated tunable microwave components that must handle room-temperature operations for multibands with wide tuning range, low power consumption, and small size. In particular, there is an increasing need for frequency-agile bandpass filters (BPFs) to replace large and costly filter banks used in the design of multiband microwave receivers [1]. In this context, significant efforts have been made since the last decade on the development of frequency-agile structures operating at microwave frequencies (above 2?GHz). Compared to semiconductor diodes [2] and RF microelectromechanical systems (MEMS) [3], ferroelectric-based devices present many advantages such as high power handling, continuous tuning, nanosecond switching speeds [4], and operation in a large frequency range with ease of fabrication and operation. Generally, the tuning is obtained by applying a bias voltage on the ferroelectric material and ferroelectric devices can be fully coplanar, very compact, and do not require hermetic packaging [5, 6]. Ferroelectric materials, in particular BaxSr1?xTiO3 (BST-x with x~0.5), present almost continuous dielectric constant tuning in the presence of an electric field and can
Intra-Articular Autologous Platelet-Rich Plasma Hip Injection May Result in Osteogenesis Depicted as an Increase in Femoral Neck Bone Density  [PDF]
Marwa A. Ahmed, Andre Panagos
Open Journal of Regenerative Medicine (OJRM) , 2014, DOI: 10.4236/ojrm.2014.32005
Abstract:

Osteoporosis has become one of the most prevalent bone diseases in developed countries. As the world’s population ages, this complex skeletal disorder is predicted to become an even more widespread and serious health condition, posing greater societal economic burden. Current therapeutic agents are limited by clinically significant side effects. In this report, we present a case that suggests intra-articular platelet-rich plasma (PRP) injectate may improve bone mineral density (BMD). This observation raises a question with exciting implications—can PRP serve as a viable and relatively safe, targeted treatment option to improve bone density?

Enhanced Thermal Stability of Promising Nano-Porous Silicon Powder  [PDF]
Marwa Nabil, Hussien A. Motaweh
Advances in Nanoparticles (ANP) , 2016, DOI: 10.4236/anp.2016.54021
Abstract:
A direct synthesis method is introduced to prepare nano-porous silicon-nickel nanocomposite (nPS/Ni) powder for thermal isolation applications. In this paper, we study the thermal stability of nanocomposites consisting of nanoparticles metal incorporated into the pores of a porous silicon by a very simple method. The nickel element is chemically deposited whereas the nanoparticles are precipitated on the pore surfaces. The (nPS) and (nPS/Ni) nano-materials are thermally measured under nitrogen at temperatures of 40 - 1000, noticeable, demonstrating better thermal stability of (nPS/Ni) until 900 than in the case of (nPS) at 600. Then, the improving of the thermal stability of the nPS powder is facilitated using it in many applications of the thermal insulation process.
Shape Control of Silica Powder Formation  [PDF]
Marwa Nabil, Hussien A. Motaweh
Journal of Materials Science and Chemical Engineering (MSCE) , 2019, DOI: 10.4236/msce.2019.73004
Abstract: The purpose of the present research is the different morphologies production of crystalline and amorphous-silica powder. It’s a basic material for many pharmaceutical and environmental applications as well. And, it’s produced using the combination of the alkali chemical etching process and the ultra-sonication technique. The critical preparation conditions are KOH concentration (weight %) and the sonication time (hour). The paper presents the chemical mechanism of the silica particle formation as well as the different morphology. The results show the formation of crystalline and amorphous-porous-silica particles in the micrometer range with the porous order network that has pore sizes range in micrometer too. This synthetic uses commercial silicon, which could be useful for large-scale production. Also, the nano-sphere and nano-cubic shapes of silica powder are formed starting by commercial silicon powder.
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