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21.
H. H. Mahmud A. Mansour F. M. Ezz-Eldin 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):261-272
Radiation indicator as well as radiation shielding of extremely high dose have been proposed. Three different types of a-SiO2 namely, G1-xerogel, G2-fused and G3-natural silica were monitored by EPR before and after γ-irradiation. The E′-center has been used for EPR radiation characterization of a-SiO2 with assuming that the signal intensity changes with γ-irradiation differently as those of other EPR signals do. Formation and decay of the E′-center are closely related with its precursor, diamagnetic oxygen vacancies. Gamma ray of large dose (500 kGy) creates oxygen vacancies giving up-and-down irradiation effects, which, therefore, might be useful for high dose radiation indicator (G1) and radiation shielding (G2 and G3). 相似文献
22.
Mahmoud Emam Doaa R. Abdel-Haleem Maha M. Salem Lina Jamil M. Abdel-Hafez Rasha R. Abdel Latif Shaimaa Mahmoud Farag Mansour Sobeh Mohamed A. El Raey 《Molecules (Basel, Switzerland)》2021,26(6)
Infections associated with the emergence of multidrug resistance and mosquito-borne diseases have resulted in serious crises associated with high mortality and left behind a huge socioeconomic burden. The chemical investigation of Lavandula coronopifolia aerial parts extract using HPLC–MS/MS led to the tentative identification of 46 compounds belonging to phenolic acids, flavonoids and their glycosides, and biflavonoids. The extract displayed larvicidal activity against Culex pipiens larvae (LC50 = 29.08 µg/mL at 72 h). It significantly inhibited cytochrome P-450 monooxygenase (CYP450), acetylcholinesterase (AChE), and carboxylesterase (CarE) enzymes with the comparable pattern to the control group, which could explain the mode of larvae toxification. The extract also inhibited the biofilm formation of Pseudomonas aeruginosa by 17–38% at different Minimum Inhibitory Concentrations (MICs) (0.5–0.125 mg/mL) while the activity was doubled when combined with ciprofloxacin (ratio = 1:1 v:v). In conclusion, the wild plant, L. coronopifolia, can be considered a promising natural source against resistant bacteria and infectious carriers. 相似文献
23.
Mansour Mohammadpour Farhad Hosseinzadeh-Lotfi Gholam-Reza Jahanshahloo 《The Journal of the Operational Research Society》2015,66(7):1206-1211
Data envelopment analysis (DEA) is a non-parametric approach based on linear programming that has been widely applied for evaluating the relative efficiency of a set of homogeneous decision-making units (DMUs) with multiple inputs and outputs. The original DEA models use positive input and output variables that are measured on a ratio scale, but these models do not apply to the variables in which negative data can appear. However, with the widespread use of interval scale data and undesirable data, the emphasis has been directed towards the simultaneous consideration of the positive and negative data in DEA models. In this paper, using the slacks-based measure, we propose an extended model to evaluate the efficiency of DMUs, even if some variables are measured on an interval scale and some on a ratio scale. Moreover, the extended model allows for the presence of all interval-scale variables, which are capable of taking both negative and positive values. 相似文献
24.
25.
An analysis is presented to investigate the effects of chemical reaction, thermal radiation and heat generation or absorption on unsteady free convective heat and mass transfer along an infinite vertical porous plate in the presence of a transverse magnetic field and Hall current. The governing partial differential equations are formulated and transformed by using a similarity transformation into a system of ordinary differential equations. The resulting equations are solved numerically using a fourth‐order Runge–Kutta scheme along with the shooting method. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. Numerical results for the velocity, temperature and concentration distributions are shown graphically for different parametric values. The effects of parameters on the local friction coefficients, the Nusselt number and Sherwood numbers are depicted in tabulated form. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
26.
B. Yan B. Li E. Baudoin C. Liu Z.W. Sun Z.S. Li X.S. Bai M. Aldén G. Chen M.S. Mansour 《Experimental Thermal and Fluid Science》2010,34(3):412-419
Experiments are carried out on partially premixed turbulent flames stabilized in a conical burner. The investigated gaseous fuels are methane, methane diluted with nitrogen, and mixtures of CH4, CO, CO2, H2 and N2, simulating typical products from gasification of biomass, and co-firing of gasification gas with methane. The fuel and air are partially premixed in concentric tubes. Flame stabilization behavior is investigated and significantly different stabilization characteristics are observed in flames with and without the cone. Planar laser induced fluorescence (LIF) imaging of a fuel-tracer species, acetone, and OH radicals is carried out to characterize the flame structures. Large eddy simulations of the conical flames are carried out to gain further understanding of the flame/flow interaction in the cone. The data show that the flames with the cone are more stable than those without the cone. Without the cone (i.e. jet burner) the critical jet velocities for blowoff and liftoff of biomass derived gases are higher than that for methane/nitrogen mixture with the same heating values, indicating the enhanced flame stabilization by hydrogen in the mixture. With the cone the stability of flames is not sensitive to the compositions of the fuels, owing to the different flame stabilization mechanism in the conical flames than that in the jet flames. From the PLIF images it is shown that in the conical burner, the flame is stabilized by the cone at nearly the same position for different fuels. From large eddy simulations, the flames are shown to be controlled by the recirculation flows inside cone, which depends on the cone angle, but less sensitive to the fuel compositions and flow speed. The flames tend to be hold in the recirculation zones even at very high flow speed. Flame blowoff occurs when significant local extinction in the main body of the flame appears at high turbulence intensities. 相似文献
27.
An asymmetric synthesis of neurokinin substance P receptor antagonist (+)-L-733,060 starting from enantiomerically pure ethyl (R)-(+)-2,3-epoxypropanoate (ethyl glycidate) is described. The synthesis relies on a diastereoselective reductive amination, regioselective intramolecular epoxide opening, and in situ cyclization as the key steps. 相似文献
28.
In this paper we define a new algebra generated by the difference operators D
q and D
q-1 with two analytic functions (x) and (x). Also, we define an operator M = J
1
J
2–J
3
J
4 s.t. all q-hypergeometric orthogonal polynomials Y
n(x), x cos(), are eigenfunctions of the operator M with eigenvalues
q
[n]
q
. The choice of (x) and (x) depend on the weight function of Y
n
(x). 相似文献
29.
Mohamadzadeh M Mohamadzadeh H Brammer M Sestak K Luftig RB 《Journal of immune based therapies and vaccines》2004,2(1):8
Dendritic cells (DC) are known to present exogenous protein Ag effectively to T cells. In this study we sought to identify
the proteases that DC employ during antigen processing. The murine epidermal-derived DC line Xs52, when pulsed with PPD, optimally
activated the PPD-reactive Th1 clone LNC.2F1 as well as the Th2 clone LNC.4k1, and this activation was completely blocked
by chloroquine pretreatment. These results validate the capacity of XS52 DC to digest PPD into immunogenic peptides inducing
antigen specific T cell immune responses. XS52 DC, as well as splenic DC and DCs derived from bone marrow degraded standard
substrates for cathepsins B, C, D/E, H, J, and L, tryptase, and chymases, indicating that DC express a variety of protease
activities. Treatment of XS52 DC with pepstatin A, an inhibitor of aspartic acid proteases, completely abrogated their capacity
to present native PPD, but not trypsin-digested PPD fragments to Th1 and Th2 cell clones. Pepstatin A also inhibited cathepsin
D/E activity selectively among the XS52 DC-associated protease activities. On the other hand, inhibitors of serine proteases
(dichloroisocoumarin, DCI) or of cystein proteases (E-64) did not impair XS52 DC presentation of PPD, nor did they inhibit
cathepsin D/E activity. Finally, all tested DC populations (XS52 DC, splenic DC, and bone marrow-derived DC) constitutively
expressed cathepsin D mRNA. These results suggest that DC primarily employ cathepsin D (and perhaps E) to digest PPD into
antigenic peptides. 相似文献
30.
Toufik Hadjersi 《Applied Surface Science》2007,253(9):4156-4160
The mechanism of metal-assisted electroless etching of silicon in HF-oxidizing agent-H2O etching system as a function of oxidizing agent concentration was studied. Three types of oxidizing agent were experimented namely Na2S2O8, K2Cr2O7 and KMnO4. Their concentrations were varied from 0.05 M to 0.3 M. The layers formed on silicon were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray (EDX). It is shown that an insoluble solid-phase film (K2SiF6) form on silicon surface when concentration of K2Cr2O7 or KMnO4 increases in chemical solutions. On other hand, when Na2S2O8 concentration increases, the surface roughness decreases without any chemical complex formation. 相似文献