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Search Results: 1 - 10 of 797 matches for " Marwa Nabil "
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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.
Photoluminescence Emission Control of Porous Silicon  [PDF]
Marwa Nabil
Soft Nanoscience Letters (SNL) , 2019, DOI: 10.4236/snl.2019.93003
Abstract: This paper reports the feasibility of synthesis and characterization of nano-porous silicon (NPS) powder and (Nickel/nano-porous silicon, Ni/NPS) nano-composite prepared using dual techniques (alkaline chemical etching process and ultra-sonication technique). The structural and the optical properties of the fabricated structures are inspected using X-ray Diffraction, Fourier Transform Infrared Spectrophotometer, Raman Spec-troscopy, and Fluorescence Spectrophotometer Photoluminescence. All the results have agreed that NPS is one of the most suitable materials used as active material in the LED fabrication; by changing the main factors in the preparation process, so the different physical and chemical properties are obtained. NPS produces two emission regions that correspond to orange-red and dark red; on the other hand, (Ni/NPS) produce the yellow emission. So, the photoluminescence emission is controllable by adjusting the preparation conditions. The optical data recorded here are useful for the production of the nanoscale optical devices.
Breast Cancer in Males (BCM), Does It Really Differ? National Cancer Institute Experience (NCI), Cairo University, Egypt  [PDF]
Ahmed El Sayed Fathalla, Marwa Nabil Abd El Hafez
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.75037
Abstract: Background: Carcinoma of the male breast is relatively a rare disease accounting for about 1% of all cancer in men. Its treatments are based mainly on those of Female Breast Cancer (BCF). Materials and Methods: This is a single institution retrospective study including all presenting to the NCI, Cairo University with Breast Cancer in a Male (BCM) in the last 11 years between Jan. 2005 until Jan. 2016. Data were collected from patient’s files from the statistical department then analyzed. Aims: To study the clinico-pathological characteristics, the presentation, workup, surgical approaches and postoperative complications and outcome of management, with addressing similarities and difference from BCF. Results: 64 patients were included in this cohort. The mean age was 58.6 & the median age was 59 years (range: 31 - 87 years). The main presenting symptomatology was retroareolar breast lump (50 cases, 78.1%). Most of our cases were advanced; 22 cases (34.3%) were stage III & 16 cases (25%) were stage IV. Surgery was performed for 50 patients; MRM for 26 cases (40.6%), RM for 18 cases (28.1%) & toilet mastectomy for 6 cases (9.3%). Primary closure was feasible in 34 patients (68%) while 16 cases (32%) required reconstruction by local or pedicled flaps. Tamoxifen is the most important non-surgical treatment. It was given to all our cases (64 cases, 100%) either postoperatively as adjuvant management (36 cases, 56.2%) or as palliation for metastatic disease (28 cases, 43.8%). Chemotherapy was given to 32 patients (100%) as an adjuvant for 24 cases (75%) and as a palliation for 8 cases (25%). Radiotherapy was given to 26 patients (100%) as adjuvant therapy for 20 cases (76.9%) and as a palliation for 6 cases (23.1%). The only significant factor determining the overall 5 years survival was the stage of the disease. LN status & surgery type were of border line significance (better survival with negative LN & with MRM). The 5-year Overall Survival (OS) & Disease Free Survival (DFS) for the whole group were 66% & 52% respectively. Within the DFS there was no significant variable; however, the stage and type of surgery were of borderline significance, with better survival with early stage disease (I & II) and with MRM (both were 61%). Conclusion: BCM has many similarities to BCF, but it harbours many different genetic and pathologic features. They obtain similar prognostic factors and similar stage-for-stage survival. They are always advanced to T4 stage rapidly due to the lack of breast parenchyma with higher ER expression in BCM
Fabrication of Congo Red/Oxidized Porous Silicon (CR/OPS) pH-Sensors  [PDF]
Abdel-Hady Kashyout, Hesham M. A. Soliman, Marwa Nabil, Ahmed A. Bishara
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.48A011
Abstract:

The fabrication of nano porous silicon, nPSi, using alkali etching process has been studied and carried out. The surface chemistry of anisotropic etching of n-type Si-wafer is reviewed and the anisotropic chemical etching of silicon in alkaline solution using wetting agents is discussed. Transformation of crystallographic plane of n-Si (211) to nPSi (100) has occurred on using n-propanol as wetting agent. The rate of pore formation was 0.02478 - 0.02827 μm/min, which was heavily dependent upon the concentration of the etchant containing wetting agents, allowing patterned porous silicon formation through selective doping of the substrate. A particle size of 15 nm for porous nano-silicon was calculated from the XRD data. Porosity of PS layers is about 10%. Pore diameter and porous layer thickness are 0.0614 nm and 16 μm, respectively. The energy gap of the produced porous silicon is 3.3 eV. Furthermore, the combination of PS with Congo Red, which are nanostructured due to their deposition within the porous matrix is discussed. Such nano compounds offer broad avenue of new and interesting properties depending on the involved materials as well as on their morphology. Chemical route was utilized as the host material to achieve pores filling. They were impregnated with Congo Red, which gave good results for the porous silicon as a promising pH sensor.

The C161T Polymorphism in Peroxisome Proliferator-Activated Receptor ɣ2, but Not Pro12Ala, Is Associated with Diabetic Retinopathy in Type 2 Diabetes Mellitus in an Egyptian Population  [PDF]
Ragaa Abelkader Ramadan, Moyassar Ahmad Zaki, Lubna Mohamed Desouky, Marwa Ahmed Madkour, Karim Mahmoud Nabil Mohamed Kamel
Journal of Diabetes Mellitus (JDM) , 2016, DOI: 10.4236/jdm.2016.61001
Abstract: Objectives: Diabetic retinopathy (DR) is one of the most common microvascular complications of type 2 diabetes mellitus (T2DM). It is multifactorial with the contribution of multiple genetic factors. We questioned the association of polymorphisms in the peroxisome proliferator-activated receptor 2 (PPAR2) gene (Pro12Ala and C161T) with DR in an Egyptian population. Methods: This case control study included one hundred healthy individuals and 252 T2DM among them 122 with DR and 130 without DR. Genotyping was done by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Results: The Pro12Ala Ala allele was associated with decreased risk of DR with an odds ratio (OR) of 0.484, 95% confidence interval (CI) (0.254 - 0.920), and a p value = 0.024. The C161T T allele was associated with increased risk of DR with OR = 2.593, 95% CI (1.672 - 4.020), p < 0.001. However, when considering other covariates such as glycosylated hemoglobin (HbA1c) in multivariate regression analysis only C161T was associated with increased risk of DR with OR = 3.479, 95% CI (1.907 - 6.346), p < 0.001, while the significant association with Pro12Ala was lost. HbA1c was higher in Pro/Pro genotype when compared to those with Ala/Ala and Pro/Ala genotypes. Conclusion: We report that T allele of C161T increased risk of DR in the studied population. Further studies are warranted to investigate functional implications of polymorphisms of the PPAR- gene in DR development.
Improving Rule Base Quality to Enhance Production Systems Performance  [PDF]
Nabil Arman
International Journal of Intelligence Science (IJIS) , 2013, DOI: 10.4236/ijis.2013.31001
Abstract: Production systems have a special value since they are used in state-space searching algorithms and expert systems in addition to their use as a model for problem solving in artificial intelligence. Therefore, it is of high importance to consider different techniques to improve their performance. In this research, rule base is the component of the production system that we aim to focus on. This work therefore seeks to investigate this component and its relationship with other components and demonstrate how the improvement of its quality has a great impact on the performance of the production system as a whole. In this paper, the improvement of rule base quality is accomplished in two steps. The first step involves re-writing the rules having conjunctions of literals and producing a new set of equivalent rules in which long inference chains can be obtained easily. The second step involves augmenting the rule base with inference short-cut rules devised from the long inference chains. These inference short-cut rules have a great impact on the performance of the production system. Finally, simulations are performed on randomly generated rule bases with different sizes and goals to be proved. The simulations demonstrate that the suggested enhancements are very beneficial in improving the performance of production systems.
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?

Histopathological and Immunohistochemical Study of E-cadherin in Breast Neoplasia
Marwa Elshaer
Journal of Medical Sciences , 2007,
Abstract: Immunohistochemical staining was undertaken for E-cadherin (EC), estrogen and progesterone receptors; on tissue sections of normal breast, proliferative breast lesions and malignant breast lesions. The EC positive expression manifested itself as sharp membranous staining and was assessed semi-quantitative into four categories: 0; 1+ were considered negative immunoreactivity, while 2+ and 3+ were scored as positive immunoreactivity. Although 95% of non malignant proliferative breast lesions showed positive EC immunoreactivity and reduced or lost EC expression in all Pre-invasive cases. None of invasive lobular cases express EC, in contrast to 30% of invasive duct carcinoma cases, showed reduced or lost EC expression in high histological grades. Correlation between the EC staining intensity and IDC, ILC and TC groups, statistical analysis was highly significant only for TC (p< 0.001). There was a significant relationship between E-cadherin expression and different breast neoplastic histological types. The molecular signature of breast lobular carcinomas is the loss of E-cadherin protein expression as evidenced by immunohistochemistry, whereas ductal carcinomas are typically E-cadherin positive. Present study suggests that E-cadherin may be involved in the pathogenesis of this form of breast cancer.
Energy of surface states for 3D magnetic Schrodinger operators
Marwa Nasrallah
Mathematics , 2014,
Abstract: We establish a semi-classical formula for the sum of eigenvalues of a magnetic Schrodinger operator in a three-dimensional domain with compact smooth boundary and Neumann boundary conditions. The eigenvalues we consider have eigenfunctions localized near the boundary of the domain, hence they correspond to surface states. Using relevant coordinates that straighten out the boundary, the leading order term of the energy is described in terms of the eigenvalues of model operators in the half-axis and the half-plane.
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