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Synthesis of Certain Mercapto and Aminopyrimidine Derivatives as Potential Antimicrobial Agents
El-Kerdawy, M.M.,Eisa, H.M.,El-Emam, A.A.,Massoud, M.A.,Nasr, M.N. The Pharmaceutical Society of Korea 1990 Archives of Pharmacal Research Vol.13 No.2
Reaction of ethyl 4-chloro-2-phenylpyrimidine-4-carboxylate (4) with 5-chloro-2-methylthiophenol or 3-aryl-4-phenyl-1, 2, 4-triazole-5 thiol yielded the corresponding thioethers (5) and (8a, b), respectively. Careful alkaline hydrolysis of (5) yielded the corresponding carboxylic acid (6). Reaction of (4) with p-aminoacetophenone yielded compound (10) which was reacted with certain aromatic aldehyde to afford the$\alpha,\beta$-unsaturated ketones (11a-d). Condensation of (11a-d) with malononitrile or phenylhydrazine yielded the 2-amino-3-cyanopyridines (12a-f) or the 2-pyrazolines (13a, b) respectively. Seven representative compounds were tested for their in vitro antimicrobial activity against some pathogenic micro-organisms, some of them were proved to be active.
Laser Acceleration of Electron Beams to the GeV-class Energies in Gas Jets
Nasr A. M. Hafz,Tae Moon Jeong,Seong Ku Lee,최일우,Ki Hong Pae,Victor V. Kulagin,Jae Hee Sung,Tae Jun Yu,John R. Cary,고도경,Jongmin Lee 한국광학회 2009 Current Optics and Photonics Vol.13 No.1
In a laser-plasma wakefield accelerator, the ponderomotive force of an ultrashort high intensity laser pulse excites a longitudinal wave or plasma bubble in a way similar to the excitation of a wake wave behind a boat as it propagates on the water surface. Electric fields inside the plasma bubble can be several orders of magnitude higher than those available in conventional RF-based particle accelerator facilities which are limited by material breakdown. Therefore, if an electron bunch is properly phase-locked with the bubble’s acceleration field, it can gain relativistic energies within an extremely short distance. Here, in the bubble regime we show the generation of stable and reproducible sub GeV, and GeV-class electron beams. Supported by three-dimensional particle-in-cell simulations, our experimental results show the highest acceleration gradients produced so far. Simulations suggested that the plasma bubble elongation should be minimized in order to achieve higher electron beam energies.
M. M. Rashad,M. I Nasr 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.3
Nanocrystalline manganese zinc ferrites (MnXZn1-XFe2O4) powders with Mn 2+ions ratio (x) varying from 0.3to 0.9 have synthesized by co-precipitation method. The results show that single MnXZn1-XFe2O4 phase forms at annealing temperature 1000°C for 2 h. The lattice parameter and crystallite size of the produced Mn-Zn ferrites powders increase with increasing the Mn 2+ion molar ratio. The microstructure and magnetic properties of the produced MnXZn1-XFe2O4 powders depend on the temperature and Mn 2+ion content. The morphology of Mn0.8Zn0.2Fe2O4 powder clearly appears as a homogeneous octahedral-like structure. The saturation magnetization of the Mn-Zn ferrite powders increase as the result of increasing Mn 2+ion ratio to 0.8. A high saturation magnetization (73.64 emu/g) achieves for the Mn0.8Zn0.2Fe2O4 powders annealed at 1100°C for 2 h.
M. Peyvandi,M. Zafarani,E. Nasr 대한전기학회 2011 Journal of Electrical Engineering & Technology Vol.6 No.2
Genetic algorithms (GA) and particle swarm optimization (PSO) are the most famous optimization techniques among various modern heuristic optimization techniques. These two approaches identify the solution to a given objective function, but they employ different strategies and computational effort; therefore, a comparison of their performance is needed. This paper presents the application and performance comparison of the PSO and GA optimization techniques for a static synchronous series compensator-based controller design. The design objective is to enhance power system stability. The design problem of the FACTS-based controller is formulated as an optimization problem, and both PSO and GA optimization techniques are employed to search for the optimal controller parameters.
The Effect of Superplasticizers on Eco-friendly Low-Energy One-Part Alkali-Activated Slag
M. Refaie,Alaa Mohsen,El-Sayed A. R. Nasr,Mohamed Kohail 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.6
One-part alkali-activated materials (OP-AAM) have become a promising binder with low carbon and energy requirements associated with superior mechanical and durability characteristics. This study aims to employ commercial superplasticizers (naphthalene-based “Nb-SP” and polycarboxylate-based “PCb-SP”), as well as laboratory-prepared one (phenol–formaldehyde sulfanilate “PFS-SP”) in enhancing the properties of OP-AAM. The main problem of superplasticizers (SPs) in the AAM is their hydrolysis in the alkaline activator (NaOH) used in the activation reactions. Therefore, the thermo-chemical treatment process was utilized to mitigate the high activator alkalinity by impeding the NaOH in the aluminosilicate precursor matrix. The OP-AAM was fabricated from thermo-chemical treatment powder (TCT-P) resulting from sintering blast furnace slag (GGBFS) with 10 wt% NaOH at 300 and 500 °C. The XRD-pattern showed that NaOH was impeded in the GGBFS via sodium aluminum silicate phase formation after sintering at 500 °C. The results showed that the admixed OP-AAM prepared from TCT-P at 500 °C greatly enhanced the workability and mechanical properties. The PFS-SP proved its efficiency in improving the properties of OP-AAM prepared TCT-P at 300 and 500 °C, referring to its high stability in an alkaline medium. While PCb-SP reinforced the properties of OP-AAM prepared from TCT-P at 500 °C only, proving that PCb-SP promotes high capability in TCT-P-500 as well as in Portland cement.
G. M. Nasr,M. Amin,H. M. Shaker 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.2
The influence of physical aging on the dielectric relaxation of the interpenetrating polymer network (IPN) composites is investigated by means of the thermally stimulated depolarization current (TSDC) technique. A generalized Bucci and Fieschi equation is used to obtain the dependence of the relaxation time on PP_y contents in the IPN composites. Moreover, the Adam and Gibbs (AG) theory is used to relate the relaxation time to structural parameters, such as the configurational entropy for these IPN composites.
Peyvandi, M.,Zafarani, M.,Nasr, E. The Korean Institute of Electrical Engineers 2011 Journal of Electrical Engineering & Technology Vol.6 No.2
Genetic algorithms (GA) and particle swarm optimization (PSO) are the most famous optimization techniques among various modern heuristic optimization techniques. These two approaches identify the solution to a given objective function, but they employ different strategies and computational effort; therefore, a comparison of their performance is needed. This paper presents the application and performance comparison of the PSO and GA optimization techniques for a static synchronous series compensator-based controller design. The design objective is to enhance power system stability. The design problem of the FACTS-based controller is formulated as an optimization problem, and both PSO and GA optimization techniques are employed to search for the optimal controller parameters.
Neurologic Complications of Extracorporeal Membrane Oxygenation
Deena M Nasr,Alejandro A Rabinstein 대한신경과학회 2015 Journal of Clinical Neurology Vol.11 No.4
Background and Purpose Te rate and outcomes of neurologic complications of patients receiving extracorporeal membrane oxygenation (ECMO) are poorly understood. Te purpose of this study was to identify these parameters in ECMO patients. Methods All patients receiving ECMO were selected from the Nationwide Inpatient Sample between 2001–2011. Te rate and outcomes of neurologic complications [acute ischemic stroke, intracranial hemorrhage (ICH), and seizures] among these patients was determined. Discharge status, mortality, length of stay, and hospitalization costs were compared between patients with and without neurologic complications using chi-squared tests for categorical variables and Student’s t-test for continuous variables. Results In total, 23,951 patients were included in this study, of which 2,604 (10.9%) suffered neurologic complications of seizure (4.1%), stroke (4.1%), or ICH (3.6%). When compared to patients without neurologic complications, acute ischemic stroke patients had signifcantly higher rates of discharge to a long-term facility (12.2% vs. 6.8%, p<0.0001) and a signifcantly longer mean length of stay (41.6 days vs. 31.9 days, p<0.0001). ICH patients had signifcantly higher rates of discharge to a long-term facility (9.5% vs. 6.8%, p=0.007), signifcantly higher mortality rates (59.7% vs. 50.0%, p<0.0001), and a signifcantly longer mean length of stay (41.8 days vs. 31.9 days) compared to patients without neurologic complications. These outcomes did not differ significantly between seizure patients and patients without neurologic complications. Conclusions Given the increasing utilization of ECMO and the high costs and poor outcomes associated with neurologic complications, more research is needed to help determine the best way to prevent these sequelae in this patient population.