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71.
Zineb Achouri Nour Eddine Amroun Abbes Benaissa 《Mathematical Methods in the Applied Sciences》2017,40(11):3837-3854
We consider a Euler–Bernoulli beam equation with a boundary control condition of fractional derivative type. We study stability of the system using the semigroup theory of linear operators and a result obtained by Borichev and Tomilov. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
72.
The numerical simulation of interaction between structures and two‐phase flows is a major concern for many industrial applications. To address this challenge, the motion of structures has to be tracked accurately. In this work, a discrete forcing method based on a porous medium approach is proposed to follow a nondeformable rigid body with an imposed velocity by using a finite‐volume Navier‐Stokes solver code dedicated to multiphase flows and based on a two‐fluid approach. To deal with the action reaction principle at the solid wall interfaces in a conservative way, a porosity is introduced allowing to locate the solid and insuring no diffusion of the fluid‐structure interface. The volumetric fraction equilibrium is adapted to this novelty. Mass and momentum balance equations are formulated on a fixed Cartesian grid. Interface tracking is addressed in detail going from the definition of the porosity to the changes in the discretization of the momentum balance equation. This so‐called time‐ and space‐dependent porosity method is then validated by using analytical and elementary test cases. 相似文献
73.
Maroua Ait Tastift Rachida Makbal Thouria Bourhim Zineb Omari Hiroko Isoda Chemseddoha Gadhi 《Molecules (Basel, Switzerland)》2022,27(10)
Saffron is the most expensive spice in the world. In addition to its culinary utilization, this spice is used for medicinal purposes such as in pain management. In this study, the analgesic activity of Crocus sativus stigma extract (CSSE) was evaluated in rodents and its possible physiological mechanism was elucidated. The anti-nociceptive effect of CSSE was evaluated using three animal models (hot plate, writhing, and formalin tests). The analgesic pathways involved were assessed using various analgesia-mediating receptors antagonists. The oral administration of CSSE, up to 2000 mg/kg, caused no death or changes in the behavior or in the hematological and biochemical blood parameters of treated animals nor in the histological architecture of the animals’ livers and kidneys. CSSE showed a central, dose-dependent, anti-nociceptive effect in response to thermal stimuli; and a peripheral analgesic effect in the test of contortions induced by acetic acid. The dual (central and peripheral) analgesic effect was confirmed by the formalin test. The anti-nociceptive activity of CSSE was totally or partially reversed by the co-administration of receptor antagonists, naloxone, atropine, haloperidol, yohimbine, and glibenclamide. CSSE influenced signal processing, by the modulation of the opioidergic, adrenergic, and muscarinic systems at the peripheral and central levels; and by regulation of the dopaminergic system and control of the opening of the ATP-sensitive K+ channels at the spinal level. The obtained data point to a multimodal mechanism of action for CSSE: An anti-inflammatory effect and a modulation, through different physiological pathways, of the electrical signal generated by the nociceptors. Further clinical trials are required to endorse the potential utilization of Moroccan saffron as a natural painkiller. 相似文献
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75.
Praveen Martis Antonio Fonseca Zineb Mekhalif Joseph Delhalle 《Journal of nanoparticle research》2010,12(2):439-448
Cu (I) phenyl acetylide was used as a source of copper to achieve a homogeneous distribution of Cu2O nanocrystals (10–80 nm) decorated on multiwalled carbon nanotubes (MWCNTs) having an average diameter of 10 nm. Pristine
MWCNTs were first oxygen-functionalized by treating them with a mixture of concentrated (H2SO4/HNO3 : 3/1) acids and the products were characterized by X-ray powder diffraction, transmission and scanning electron microscopy,
energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and thermogravimetric analysis. An easy, efficient and
one-step impregnation method was followed to produce copper-containing nanoparticles on the MWCNTs. The copper-treated MWCNTs
dried at room temperature were seen to be well decorated by copper-containing nanoparticles on their outer surface. The MWCNTs
were then heat-treated at 400 °C in a nitrogen atmosphere to produce a homogeneous distribution of cuprous oxide nanocrystals
on their surface. By varying the ratio of copper to oxygen-functionalized MWCNTs, Cu2O nanocrystals decorated on MWCNTs with different copper content can be obtained. 相似文献
76.
Zineb Guerrab Boujemaâ DaouSouad Fkih-Tetouani Mohammed AhmarBernard Cazes 《Tetrahedron letters》2003,44(30):5727-5730
Bicyclic δ-lactones, iridolactones analogs with an alkyl group at the bicyclic junction, are obtained from α-alkyl-α-hydroxymethylcyclopentanones via an intramolecular Horner-Wadsworth-Emmons reaction. 相似文献
77.
78.
Sara Boughaba Zineb Aouf Ouahiba Bechiri Monique Mathe-Allainmat Jacques Lebreton 《Phosphorus, sulfur, and silicon and the related elements》2021,196(1):28-35
Abstract A simple, efficient and eco-friendly protocol has been described for the synthesis of α-aminophosphonates via Kabachnik-Fields reaction, catalyzed by H6P2W18O62·14H2O as a reusable catalyst. The reaction was realized by condensation of amino acids, various aromatic aldehydes and triethylphosphite under solvent-free conditions, the corresponding α-aminophosphonates were formed in good yields. All the new products were characterized by IR, 1H, 13C and 31P-NMR analyses. This method offers advantages such as simplicity workup with the green aspects, good yields and short reaction times. 相似文献
79.
Brahim Hacht Hassan Tayaa Ahmed Benayad Mostafa Mimouni 《Journal of solution chemistry》2002,31(9):757-769
A quantitative study of zinc(II) and copper(II) complex formation with orotic acid has been performed under physiological conditions (37°C; 0.15 mol-dm–3 NaCl) using the glass electrode potentiometric technique. Several species have been identified within the pH range 2–10 for the metal-to-ligand concentration ratios investigated. Three mononuclear complexes, ML, ML2, and ML2H–1, have been characterized with both metals. In addition, the polynuclear species M3L2H–2 has been found with copper(II). Formation constants for all these species have been calculated with the help of the SUPERQUAD computer program. UV absorption and IR spectroscopic measurements combined with speciation calculations have been used to confirm corresponding structures. 相似文献
80.
Gérald Franz Farid Abed-Meraim Jean-Paul Lorrain Tarak Ben Zineb Xavier Lemoine Marcel Berveiller 《International Journal of Plasticity》2009
In order to investigate the impact of microstructures and deformation mechanisms on the ductility of materials, the criterion first proposed by Rice is applied to elastic–plastic tangent moduli derived from a large strain micromechanical model combined with a self-consistent scale-transition technique. This approach takes into account several microstructural aspects for polycrystalline aggregates: initial and induced textures, dislocation densities as well as softening mechanisms such that the behavior during complex loading paths can be accurately described. 相似文献