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Performance Comparison between Delay-Tolerant and Non-Delay-Tolerant Position-Based Routing Protocols in VANETs  [PDF]
Ahmed Mohamed Abdalla, Salem H. Salamah
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2022, DOI: 10.4236/ijcns.2022.151001
Abstract: Vehicular ad hoc networks (VANETs) are a new emerging recently developed advanced technology that allows a wide group of applications related to providing more safety on roads, more convenience for passengers, self-driven vehicles, and intelligent transportation systems (ITS). There are various routing protocol categories used in VANETs, like unicast, multicast, and broadcast protocols. In unicast position-based protocols, the routing decisions are based on the geographic position of the vehicles. This does not require establishment or maintenance of routes but needs location services to determine the position of the destination. Non-delay-tolerant network protocols (non-DTN), also identified as minimum delay protocols, are aimed at minimizing the delivery time of the information. Delay-tolerant protocols (DTN) are used in a variety of operating environments, including those that are subject to failures and interruptions and those with high delay, such as VANETs. This paper discusses the comparison between non-DTN and DTN routing protocols belonging to the unicast delay-tolerant position-based category. The comparison was conducted using the NS2 simulator, and the simulations of three non-DTN routing protocols and three DTN routing protocols were recorded. Simulation results show that the DTN routing protocols outperform in delivery ratio compared to the non-DTN routing protocols, but they lead to more average delay due to buffering, the processing algorithm, and priority calculation. In conclusion, non-DTN protocols are more suitable for the city environment since the distance between nodes is relatively smaller and the variations in the network topology are slower than they are on highways. On the other hand, DTN protocols are more suitable for highways due to the buffering of packets until a clear route to destination is available.
Effect of Nanoparticles Reinforced Adhesive Layers on Microleakage of Tooth Restorations  [PDF]
Mohamed I. Ebrahim, Mohamed Ashour Ahmed, Nayef H. Felemban
World Journal of Nano Science and Engineering (WJNSE) , 2016, DOI: 10.4236/wjnse.2016.62008
Abstract: Adhesive layer is an essential part of tooth colored restorations which play an important role in decreasing the microleakage between the tooth and restoration material after polymerization shrinkage. The purpose of this study was to evaluate the effect of deferent adhesive system of bonding agent on microleakage of nanocomposite resin in class II cavities. Two different types of adhesive systems: universal adhesive (ExciTE) and a newly developed adhesive (Nano-Bond) and one type of light-cured resin restorative material (nanocomposite resin) were used in this study. These adhesives were applied to prepared tooth cavities by either manufactures’ instructions or by an experimental method (single or double application). Nanocomposite resin was then placed and light-cured for 40 seconds. Teeth were subjected to 500 thermal cycles between 5°C and 55°C and were immersed in 3% methylene blue solution for 24 hours; microleakage was observed microscopically. The data were analyzed by a two-way ANOVA. For comparison between groups, Tukey’s post-hoc test was used. Nanoparticles reinforced adhesive system shows low microleakage in compare with universal adhesive system, and application of two adhesive layers also can decrease the microleakage. The ability of stress absorption by adhesive layer after polymerization shrinkage of restoration material will reduce the microleakage.
Ezetimbe as potential treatment for cholesterol gallstones: The need for clinical trials
Mohamed H Ahmed
World Journal of Gastroenterology , 2010,
Abstract: Obesity is associated with insulin resistance, non-alcoholic fatty liver disease (NAFLD) and gallstones. High fat diets (unsaturated fats) rich in cholesterol have been demonstrated to produce not only gallstones but also NAFLD and insulin resistance. Interestingly, a high incidence of gallstones is being reported in association with insulin resistance and NAFLD. Laparoscopic cholecystectomy is the best definitive therapy for symptomatic gallbladder disease. Ezetimibe is a drug that inhibits the absorption of both dietary and biliary cholesterol in the small intestine. Importantly, ezetimibe showed potential benefit not only in treating and preventing gallstones but also in insulin resistance and NAFLD. Further studies are required before the use of ezetimibe for the treatment of gallstones can be advocated.
Extraction of Copper from Waste Solution Using Liquid Emulsion Membrane  [PDF]
Y.T. Mohamed, Ahmed M. H. Ibrahim
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.31016
Abstract: The extraction of copper from acidic medium using Liquid Emulsion Membrane LEM as contactors was studied. b diketone LIX 54 as an extractant ,sesqueoleate which is nonionic surfactant with HLB value 3.7 and 0.1 M H2SO4 as stripping solution were used. The influence of initial concentration of copper in the aqueous feed phase, pH of external and internal aqueous phase, stirring speed, and concentration of extractant on the extraction rate was examined. The results obtained showed that practically all the copper content was removed from the acidic feed solution. The recovery of copper attained 96–100% and concentration ratios of about 40-fold could be achieved.
3D-Analysis of Soil-Foundation-Structure Interaction in Layered Soil  [PDF]
Mohd Ahmed, Mahmoud H. Mohamed, Javed Mallick, Mohd Abul Hasan
Open Journal of Civil Engineering (OJCE) , 2014, DOI: 10.4236/ojce.2014.44032
Abstract: The analysis of building structure in contact with soil involves an interactive process of stresses and strains developed within the structure and the soil field. The response of Piled-Raft Foundation system to the structure is very challenging because there is an important interplay between the component of building structure and the soil field. Herein, soil-foundation-structure interaction of buildings founded on Piled-Raft Foundation is evaluated through 3D-Nonlinear Finite Element Analyses using PLAXIS3D FOUNDATION code. The soil settlements and forces demand of the high-rise building structures and foundation is computed. The parametric study affecting the soil-foundation-structure response has been carried out. The parameters such as construction phasing, sequential loading, building aspect ratios, soil failure models and thickness proportion of soil field stiff layer, are considered. It is concluded that the interaction of building foundation-soil field and super-structure has remarkable effect on the structure.
Optimum Timing and Complication of Completion Thyroidectomy for Differentiated Thyroid Cancer  [PDF]
Mohamed Abouelmagd Salem, Badawy M. Ahmed, Mahmoud H. Elshoieby
Journal of Cancer Therapy (JCT) , 2017, DOI: 10.4236/jct.2017.85044
Abstract: Background: Despite improved preoperative diagnostics, incidental postoperative detection of differentiated thyroid cancer in the final histology is still common. In most of these cases, completion thyroidectomy is recommended by national and international guidelines, although secondary surgery is associated with an increased operative risk. The optimal timing of completion thyroidectomy is still controversial. Patients and Methods: The patients admitted to surgical oncology department, SECI, with diagnosis of differentiated thyroid cancer; during the period from January 2008 to December 2015; were rewired for age, sex, type of 1st operation, histopathological result, type of 2nd operation and time interval between the 2 operation, complication of 2nd operation and morbidity. 118 patients underwent completion thyroidectomy; those patients were divided according to timing of completion operation into 3 groups: Group A is from one week to 3 months and include 64 patients; Group B is from 3 - 6 months and include 30 patients; Group C is more than 6 months and include 24 patients. Clinical complications and oncologic outcomes were analyzed. The mean follow-up was 80 ± 10 months. Result: we record 118 patients under completion thyroidectomy. Ages range from 79 to 13 years. Papillary thyroid cancer were 96 and follicular thyroid cancer were 22. The overall rates of transient and persistent postoperative hypocalcemia were 19.5% and 4.2%, respectively. The rates of persistent hypocalcemia were found in group A and B but not in group C. Transient or persistent vocal cord paresis was observed in 9 (7.6%) and 3 patients (2.5%). The incidence of persistent vocal cord paresis (VCP) was significantly higher in groups A and B than in group C. There was no significant difference regarding survival among the 3 groups; however recurrence is higher in group A. Conclusion: Considering perioperative morbidity and oncologic outcomes, completion thyroidectomy should be performed at least 3 to 6 months after primary surgery.
Endoscopic Skull Base Surgery in Assiut University, Single Center Early Experience  [PDF]
Mohamed A. Ragaee, Ahmed H. Monib, Ahmad Abdalla
Open Journal of Modern Neurosurgery (OJMN) , 2020, DOI: 10.4236/ojmn.2020.101008
Abstract: Background: Endoscopic transnasal skull base surgery had started long time ago in different centers around the world for excision of skull base lesions with good results and more cost effectiveness. The aim of this study is to discuss our early results in endoscopic skull base surgery and the development of the learning curve. Patients and Methods: We analyzed our experience regarding 25 patients presented to us in Neurosurgery Department, Assiut University Hospital, Assiut University, Assiut, Egypt in a period of 3 years (2015, 2016, 2017) and operated by endoscopic transnasal approach. All patients signed an informed consent. Results: With the highest percentage was pituitary adenoma 56%, pituitary apoplexy 12%, craniopharyngioma 12%, CSF rhinorrhea 12%, Planum sphenoidal meningioma 4% and suprasellar granuloma 4%. 88% of patients were operated without complications, 8% mortality rate postoperative, 12% complication rate and 76% complete improvement postoperative. Conclusion: Endoscopic skull base surgery is a safe approach to the skull base that needs a good experience, practice and good anatomical knowledge. Teamwork between a Neurosurgeon and ENT surgeon is a must for patient safety.
Logic Picture-Based Dynamic Power Estimation for Unit Gate-Delay Model CMOS Circuits  [PDF]
Omnia S. Ahmed, Mohamed F. Abu-Elyazeed, Mohamed B. Abdelhalim, Hassanein H. Amer, Ahmed H. Madian
Circuits and Systems (CS) , 2013, DOI: 10.4236/cs.2013.43037
Abstract: In this research, a fast methodology to calculate the exact value of the average dynamic power consumption for CMOS combinational logic circuits is developed. The delay model used is the unit-delay model where all gates have the same propagation delay. The main advantages of this method over other techniques are its accuracy, as it is deterministic and it requires less computational effort compared to exhaustive simulation approaches. The methodology uses the Logic Pictures concept for obtaining the nodes’ toggle rates. The proposed method is applied to well-known circuits and the results are compared to exhaustive simulation and Monte Carlosimulation methods.
Antioxidant Activity and Lipoxygenase Inhibitory Effect of Caralluma arabica and Related Polyphenolic Constituents  [PDF]
Mohammad Khasawneh, Hanan Mohamed Elwy, Nael Mohamed Fawzi, Alaaeldin Ahmed Hamza, Abdul Raheem Chevidenkandy, Ahmed H. Hassan
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.511176
Abstract:

Phytochemicals have been of great interest as a source of natural antioxidants used for health promotion, food preservation, food flavoring and cosmetics. In this research, alcoholic extract from Caralluma arabica and different solvent fractions were evaluated for their antioxidant, anti-inflammatory and anti-cancer properties as well as their polyphenolic compositions. The total antioxidant property was estimated by the ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS+) and β-carotene bleaching tests. Among the ethanol extract and three fractions, the ethyl acetate fraction showed the highest phenolic content (33.1 mg gallic acid/g) and the best antioxidant activity. The ascorbic acid equivalent antioxidant capacities of the ethyl acetate fraction were 143.64, 381.3, 112.6 μmol/g in FRAP, ABTS and DPPH assays, respectively. This study verified that the ethanol extract and ethyl acetate fraction from Caralluma arabica have strong antioxidant activity that was correlated with their high level of phenolic content. Furthermore, the same extract showed appreciable anti-inflammatory via Lipoxygenase inhibitory activity (LOX), the IC50 values ranged from 11.2 - 30.77 μg/mL. Moreover, Ethyl acetate fraction showed the strongest cytotoxic effect (IC50 = 87.55 μg/mL) against MCF-7 breast cancer cell line. These findings suggest that Caralluma arabica may be considered as an interesting source

“Pyridopyridazine”: A Versatile Nucleus in Pharmaceutical Field  [PDF]
Mohamed A. Ibrahim, Ahmed H. Elmenoufy, Mohamed Elagawany, Mohammed M. Ghoneim, Alaa Moawad
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.310008
Abstract: Pyridopyridazines are an important kind of nitrogen atom containing heterocyclic compounds due to their synthetic and pharmacological versatility. This fused heterocycle system represents a common structural feature for many bioactive compounds showing a variety of pharmacological activities which makes it an attractive scaffold for the design and development of new drugs. This mini review summarizes an updated information described in recent literature, about the most relevant pharmacological properties of pyridopyridazines derivatives.
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