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941.
Mostafa M. Ghorab Marwa G. El-Gazzar Mansour S. Alsaid 《International journal of molecular sciences》2014,15(5):7539-7553
4-Aminoantipyrine was utilized as key intermediate for the synthesis of pyrazolone derivatives bearing biologically active moieties. The newly synthesized compounds were characterized by IR, 1H- and 13C-NMR spectral and microanalytical studies. The compounds were screened as anticancer agents against a human tumor breast cancer cell line MCF7, and the results showed that (Z)-4-((3-amino-5-imino-1-phenyl-1H-pyrazol-4(5H)-ylidene)methylamino)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 5, 3-(4-bromophenyl) -1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 13, 1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1-Hpyrazol- 4-yl)-3-(4-iodophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 14, 3,3′-(4,4′-sulfonylbis(4,1-phenylene))bis(1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol- 4-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile) 16, (Z)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-hydrazono-4-oxo-3-phenyl-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 17, (Z)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-oxo-3-phenyl-2-(2-phenylhydrazono)-1,2,3,4-tetrahydro pyrimidine-5-carbonitrile 18, and (Z)-4-(3-amino-6-hydrazono-7-phenyl-6,7-dihydro pyrazolo[3,4-d]pyrimidin-5-yl)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 19 were the most active compounds with IC50 values ranging from 30.68 to 60.72 μM compared with Doxorubicin as positive control with the IC50 value 71.8 μM. 相似文献
942.
Asma Chetouani Meriem Elkolli Mahmoud Bounekhel Djafer Benachour 《Polymer Bulletin》2014,71(9):2303-2316
Gelatin (G) edible films with a new kind of dialdehyde polysaccharide, oxidized pectin (OP) as crosslinking agent are successfully prepared using casting techniques. FTIR and X-ray diffraction studies demonstrate that crosslinking is achieved through the reaction of aldehyde groups of oxidized pectin with the free amino groups in gelatin with a small affectation of the triple helix of gelatin. The qualitative and quantitative data about structures of films were determined by atomic force microscopy. Thermogravimetric analysis reveals that G/OP film has improved thermal stability in comparison with pure gelatin. Examination of the hemolytic potential showed that the obtained hydrogels are non-hemolytic in nature. These hydrogels are also nontoxic and blood-compatible. This kind of hydrogel is expected to be useful in the biomedical field, e.g., as wound dressing. 相似文献
943.
944.
Yin Ling Tan Denny K.S. Ng Mahmoud M. El-Halwagi Dominic C.Y. Foo Yudi Samyudia 《Chemical Engineering Research and Design》2014
Most of the established methods for utility targeting in a heat exchanger network (HEN) are mainly focusing on fixed stream conditions, where the flow rate, heat capacity, supply and target temperatures are fixed. However, in the process industries, the stream conditions (flow rates and temperatures) are not fixed. Therefore, the established HEN targeting methods cannot be directly applied to locate the hot and cold utility targets for HEN problem with varying flow rates and temperatures. To address this issue, a revised floating pinch method which uses binary variables to parameterise the stream locations on the composite curves, is presented in this work to identify the minimum utilities targets. The revised method simplify the earlier version of floating pinch method presented by Duran and Grossmann (1986) by avoiding the non-differentiability in the mathematical program. Two cases, one with fixed parameters while another with temperature-dependent properties and varying operating parameters are solved to illustrate the revised model. 相似文献
945.
Mahmoud Abbasi Ali Reza Soleymani Jalal Basiri Parssa 《Chemical Engineering Research and Design》2014
The present work has focused on the modeling and simulation of a recycled ozone generator system via electrochemical oxidation of water. To produce ozone, a Pyrex glass electrochemical reactor, comprised of two separate half-cell by Nafion 117 membrane was applied. The applied anode and cathode electrodes were Ti/Sn-Sb-Ni and platinized titanium, respectively. The modeling and simulation of the reactor operation were done via artificial neural network (ANN) technique. In this regard, four important operational parameters (i.e. electrolyte concentration, applied voltage, flow rate and electrolysis time) and the generated ozone concentration were considered as the independent inputs and the network output, respectively. To find out the best model, six numbers of three-layered ANNs with different functions were constructed and optimized. Best simulation was related to a model, consist of Levenberg–Marquardt Back propagation learning algorithm (trainlm) and tangent sigmoid (tansig) as transfer function in the both hidden and output layers. Also, application of 10 hidden neurons and 80 iterations for the network calibration caused to satisfy the network training while overfitting was prevented. The K-fold cross-validation method, employed for the model evaluation, showed high correlation coefficient (0.9936) and low mean square error (3.58 × 10−4) for the testing data. Sensitivity analysis indicated order of relative importance the operational parameters on the ozone production as: time > [electrolyte] > voltage > flow rate. 相似文献
946.
Omar Al-Kharji Al-Ali Saleh Al-Araji Mahmoud Al-Qutayri 《International Journal of Electronics》2013,100(9):1296-1308
The mathematical analysis of the convergence behaviour of the first-order single channel digital tanlock loop (SC-DTL) is presented. This article also describes a novel technique that allows controlling the convergence speed of the loop, i.e. the time taken by the phase-error to reach its steady-state value, by using a specialised controller unit. The controller is used to adjust the convergence speed so as to selectively optimise a given performance parameter of the loop. For instance, the controller may be used to speed up the convergence in order to increase the lock range and improve the acquisition speed. However, since increasing the lock range can degrade the noise immunity of the system, in a noisy environment the controller can slow down the convergence speed until locking is achieved. Once the system is in lock, the convergence speed can be increased to improve the acquisition speed. The performance of the SC-DTL system was assessed against similar arctan-based loops and the results demonstrate the success of the controller in optimising the performance of the SC-DTL loop. The results of the system testing using MATLAB/Simulink simulation are presented. A prototype of the proposed system was implemented using a field programmable gate array module and the practical results are in good agreement with those obtained by simulation. 相似文献
947.
Masoud Mozafari Fathollah Moztarzadeh Mohammad Rabiee Mahmoud Azami Saied Maleknia Mohammadreza Tahriri Zoha Moztarzadeh Nader Nezafati 《Ceramics International》2010
In this study, macroporous bioactive nanocomposite scaffolds were developed using cross-linked gelatin and bioactive glass (BaG) nanoparticles. First, BaG nanoparticles were synthesized via sol–gel method and characterized. Then, macroporous nanocomposites were prepared through layer solvent casting combined with freeze-drying and lamination techniques. This research has developed a new composition to produce a new bioactive nanocomposite which is porous with three-dimensional (3D) inter-connected microstructure, pore sizes are 200–500 μm, porosity are 72–86% and BaG nanoparticles are dispersed evenly among cross-linked gelatin matrices. It is mentionable that in this study, we have reported the formation of chemical bonds between BaG nanoparticles and gelatin for the first time. Finally, the in vitro cytocompatibility of the nanocomposite scaffolds was tested using SaOS-2 cell line. 相似文献
948.
Salehipour M Javadi E Reza JZ Doosti M Rezaei S Paknejad M Nejadi N Heidari M 《International journal of molecular sciences》2010,11(11):4660-4672
Transformation of macrophages to foam cells is determined by the rates of cholesterol uptake and efflux. This study uses a real time RT-PCR technique to investigate the role of conjugated linoleic acid (CLA), α-linolenic acid (ALA) and eicosapentaenoic acid (EPA) in the regulation of the ATP-binding cassette A1 (ABCA1) and liver X receptor α (LXR) genes, which are involved in cholesterol homeostasis. Accordingly, these fatty acids significantly reduced the total, free and esterified cholesterols within the foam cells. While the expression of the ABCA1 and LXRα genes was increased in the presence of the pharmacological LXRα ligand, T0901317, their mRNA expression was not significantly affected by CLA, ALA and EPA. These results suggest that although polyunsaturated fatty acids have an effect on cholesterol homeostasis, they cannot change the expression of the ABCA1 and LXRα genes. Alternatively, several other genes and proteins may be involved. 相似文献
949.
This paper deals with the low voltage ride-through (LVRT) control of wind turbines with doubly fed induction generators (DFIGs) under symmetrical voltage dips. The investigation first develops a mathematical formula for the rotor current and rotor voltage when DFIG is subjected to a symmetrical voltage dip. From the analysis, the reasons of rotor inrush current and factors influencing it are inferred. Then, a control scheme enhancing the wind turbine LVRT capability is designed and simulated. The proposed control scheme consists of a nonlinear control strategy applied to the rotor-side converter and a dc-link voltage control applied to the grid-side converter. It improves the damping of DFIG transient response and minimizes oscillations of rotor current, electromagnetic torque and dc-link voltage during the generator voltage dip. It also limits the peak value of these quantities. At the end, results of theoretical analyses are verified by time domain simulations. 相似文献
950.
Mahmoud Zarei Darioush Salari Aligoli Niaei Alireza Khataee 《Electrochimica acta》2009,54(26):6651-6660
The electrochemical treatment of solutions containing C.I. Basic Yellow 2 (BY2) in aqueous solutions with carbon-PTFE (polytetrafluoroethylene) and carbon nanotube (CNT)-PTFE electrodes as cathode has been studied. The fabricated electrodes were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The amount of electrogenerated H2O2 on the surface of these electrodes was investigated, too. The results showed that the amount of H2O2 obtained with the CNT-PTFE electrode was nearly three times higher than that of carbon-PTFE electrode. The decolorization efficiency of BY2 in peroxi-coagulation process reached 62% and 96% in the first 10 min by carbon-PTFE and CNT-PTFE electrodes at 100 mA, respectively. The effect of operational parameters such as applied current, initial pH and initial dye concentration was studied in an attempt to reach higher decolorization efficiency. The degradation and mineralization of BY2 using CNT-PTFE electrode were followed by total organic carbon (TOC) and GC–MS analysis. The results of TOC measurements indicated that peroxi-coagulation with carbon-PTFE allowed 81% mineralization after 6 h of electrolysis; whereas peroxi-coagulation with CNT-PTFE yields 92% mineralization under the same conditions. GC–MS analysis verified the identity of intermediates and a reaction pathway based on them was proposed. 相似文献