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11.
Hickey OA Mercier JF Gauthier MG Tessier F Bekhechi S Slater GW 《The Journal of chemical physics》2006,124(20):204903
We derive a mean-field expression for the effective diffusion coefficient of a probe molecule in a two-phase medium consisting of a hydrogel with large gel-free solvent inclusions, in terms of the homogeneous diffusion coefficients in the gel and in the solvent. Upon comparing with exact numerical lattice calculations, we find that our expression provides a remarkably accurate prediction for the effective diffusion coefficient, over a wide range of gel concentration and relative volume fraction of the two phases. Moreover, we extend our model to handle spatial variations of viscosity, thereby allowing us to treat cases where the solvent viscosity itself is inhomogeneous. This work provides robust grounds for the modeling and design of multiphase systems for specific applications, e.g., hydrogels as novel food agents or efficient drug-delivery platforms. 相似文献
12.
Vincent Denavit Danny Lainé Chahrazed Bouzriba Elena Shanina Émilie Gillon Prof. Sébastien Fortin Prof. Christoph Rademacher Prof. Anne Imberty Prof. Denis Giguère 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(17):4478-4490
The replacement of hydroxyl groups by fluorine atoms on hexopyranoside scaffolds may allow access to invaluable tools for studying various biochemical processes. As part of ongoing activities toward the preparation of fluorinated carbohydrates, a systematic investigation involving the synthesis and biological evaluation of a series of mono- and polyfluorinated galactopyranosides is described. Various monofluorogalactopyranosides, a trifluorinated, and a tetrafluorinated galactopyranoside have been prepared using a Chiron approach. Given the scarcity of these compounds in the literature, in addition to their synthesis, their biological profiles were evaluated. Firstly, the fluorinated compounds were investigated as antiproliferative agents using normal human and mouse cells in comparison with cancerous cells. Most of the fluorinated compounds showed no antiproliferative activity. Secondly, these carbohydrate probes were used as potential inhibitors of galactophilic lectins. The first transverse relaxation-optimized spectroscopy (TROSY) NMR experiments were performed on these interactions, examining chemical shift perturbations of the backbone resonances of LecA, a virulence factor from Pseudomonas aeruginosa. Moreover, taking advantage of the fluorine atom, the 19F NMR resonances of the monofluorogalactopyranosides were directly monitored in the presence and absence of LecA to assess ligand binding. Lastly, these results were corroborated with the binding potencies of the monofluorinated galactopyranoside derivatives by isothermal titration calorimetry experiments. Analogues with fluorine atoms at C-3 and C-4 showed weaker affinities with LecA as compared to those with the fluorine atom at C-2 or C-6. This research has focused on the chemical synthesis of “drug-like” low-molecular-weight inhibitors that circumvent drawbacks typically associated with natural oligosaccharides. 相似文献
13.
Karima Belarbi Fawzia Atik-Bekkara Imad Abdelhamid El Haci Ilhem Bensaid Chahrazed Bekhechi 《Natural product research》2018,32(3):350-353
In the present paper,we reported for the first time, the identification of the phenolic compounds in butanolic fraction obtained from the leaf part of Teucrium pseudo-Scorodonia Desf. collected from Algeria using RP-HPLC-PDA (Reversed Phase High Performance Liquid Chromatography/Photo Diode Array) technique. Several standards were used for this purpose. The analysis led to the identification of six phenolic acids (ferulic, sinapic, rosmarinic, syringique, caffeic, p-coumaric acids) and one flavonoid (rutin), the last one, has interesting pharmacological properties. 相似文献
14.
S. Bekhechi A. Benyoussef A. El kenz B. Ettaki M. Loulidi 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(2):275-282
By using a mean-field approximation (MFA) and Monte-Carlo (MC) simulations, we have studied the effect on the phase diagrams
of mixed spins ( and S =1) in the Ashkin-Teller model (ATM) on a hypercubic lattice. By varying the strength describing the four spin interaction
and the single ion potential, we have obtained by these two methods quite rich phase diagrams with several multicritical points.
This model exhibits a new partially ordered phase which does not exist neither in the spin-1/2 ATM nor in the spin-1 ATM. While MFA yields phase diagrams which are sometimes
qualitatively incorrect, accurate results are obtained from MC simulations. From the critical exponents which have been calculated
using finite-size scaling ideas, we have shown that all phase transitions are Ising-like except for the paramagnetic-Baxter
critical surface on which the critical exponents vary continuously, by varying only the strength of the coupling interaction
independently of the value of the single ion potential.
Received 5 July 1999 and Received in final form 4 July 2000 相似文献
15.
F. Hontinfinde S. Bekhechi R. Ferrando 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(4):681-686
We have studied by means of Monte-Carlo simulation and exact finite-size analysis, the spin-1 Blume Capel model with Glauber
and Kawasaki dynamics. The Kawasaki spin-exchange process transfers energy into the system from an external source. Some phase
diagrams of the model are presented. For some parameter values, the system displays a kind of self-organization phenomenon
within the disordered phase.
Received 15 February 2000 相似文献
16.
Prosper Ndizeye Felix Hontinfinde Basile Kounouhewa Smaine Bekhechi 《Central European Journal of Physics》2014,12(5):375-382
An open ferromagnetic Ashkin-Teller model with spin variables 0, ±1 is studied by standard Monte Carlo simulations on a square lattice in the presence of competing Glauber and Kawasaki dynamics. The Kawasaki dynamics simulates spin-exchange processes that continuously flow energy into the system from an external source. Our calculations reveal the presence, in the model, of tricritical points where first order and second order transition lines meet. Beyond that, several self-organized phases are detected when Kawasaki dynamics become dominant. Phase diagrams that comprise phase boundaries and stationary states have been determined in the model parameters’ space. In the case where spin-phonon interactions are incorporated in the model Hamiltonian, numerical results indicate that the paramagnetic phase is stabilized and almost all of the self-organized phases are destroyed. 相似文献