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1.
The effects of temperature and concentration on the reduced electrical conductivity of solutions of poly-(sodium styrene sulfonate) (PSSNa) in N,N-dimethylformamide + water were examined at different temperatures between 20 and 60°C and concentrations levels between 0.1 and 1 g/l. The effects of temperature were described by an Arrhenius-type equation. The intrinsic conductivities [σ] and the Huggins constant khσ of PSSNa were calculated and studied. Then, dln[σ]/d(1/T) was calculated as the indices for chain ?exibility and molecule conformation, respectively.These results showed that the intrinsic electrical conductivities decreased linearly with increasing temperature, for all concentrations of PSSNa. 相似文献
2.
Emna Tefjeni 《Integral Transforms and Special Functions》2020,31(8):669-684
ABSTRACT In this paper, we present some new elements of harmonic analysis related to the right-sided multivariate continuous quaternion wavelet transform. The main objective of this article is to introduce the concept of the right-sided multivariate continuous quaternion wavelet transform and investigate its different properties using the machinery of multivariate quaternion Fourier transform. Last, we have proven a number of uncertainty principles for the right-sided multivariate continuous quaternion wavelet transform. 相似文献
3.
Ayari Faouzi Mannei Emna Asedegbega-Nieto Esther Mhamdi Mourad Guerrero-Ruiz Antonio Ricardo Delahay Gérard Ghorbel Abdelhamid 《Journal of Thermal Analysis and Calorimetry》2018,131(2):1295-1306
Journal of Thermal Analysis and Calorimetry - Thermal decomposition (2 K min?1) of ammonium heptamolybdate tetrahydrate, performed between room temperature and... 相似文献
4.
AbstractWe report herein a new method for the synthesis of 4-aryl-3,4-dihydro-2H-benzo[g]chromene-2,5,10-triones 4 that proceeds in good yields (74–86%) and mild reaction conditions between readily available 2-amino-4-aryl-5,10-dioxo-5,10-dihydro-4H-benzo[g]chromene-3-carbonitriles 1, and formic acid (88%), at reflux for 6?h. In addition, we have also studied the antioxidant activities using DPPH and total TAC methods. 相似文献
5.
In this paper, we study the quaternion windowed Fourier transform (QWFT) and prove the Local uncertainty principle, the Logarithmic uncertainty principle and Amrein Berthier for the QWFT, the radar quaternion ambiguity function and the quaternion Wigner transform. 相似文献
6.
Yosser Zina Abdelkrim Emna Harigua-Souiai Imen Bassoumi-Jamoussi Mourad Barhoumi Josette Banroques Khadija Essafi-Benkhadir Michael Nilges Arnaud Blondel N. Kyle Tanner Ikram Guizani 《Molecules (Basel, Switzerland)》2022,27(18)
Previous investigations of the Leishmania infantum eIF4A-like protein (LieIF4A) as a potential drug target delivered cholestanol derivatives inhibitors. Here, we investigated the mode of action of cholesterol derivatives as a novel scaffold structure of LieIF4A inhibitors on the RNA-dependent ATPase activity of LieIF4A and its mammalian ortholog (eIF4AI). We compared their biochemical effects on RNA-dependent ATPase activities of both proteins and investigated if rocaglamide, a known inhibitor of eIF4A, could affect LieIF4A as well. Kinetic measurements were conducted at different concentrations of ATP, of the compound and in the presence of saturating whole yeast RNA concentrations. Kinetic analyses showed different ATP binding affinities for the two enzymes as well as different sensitivities to 7-α-aminocholesterol and rocaglamide. The 7-α-aminocholesterol inhibited LieIF4A with a higher binding affinity relative to cholestanol analogs. Cholesterol, another tested sterol, had no effect on the ATPase activity of LieIF4A or eIF4AI. The 7-α-aminocholesterol demonstrated an anti-Leishmania activity on L. infantum promastigotes. Additionally, docking simulations explained the importance of the double bond between C5 and C6 in 7-α-aminocholesterol and the amino group in the C7 position. In conclusion, Leishmania and mammalian eIF4A proteins appeared to interact differently with effectors, thus making LieIF4A a potential drug against leishmaniases. 相似文献
7.
Emna Choura Fares Elghali Paul J. Bernard Dhouha Msalbi Jos Marco-Contelles Sami Aifa Lhassane Ismaili Fakher Chabchoub 《Molecules (Basel, Switzerland)》2022,27(22)
Ten new differently substituted 3-benzyl-5-aryl-3,5-dihydro-4H-benzo[6,7]chromeno[2,3-d]pyrimidin-4,6,11-triones 3 were synthesized by a simple and cost-efficient procedure in a one-pot, three-component reaction from readily available ethyl 2-amino-4-aryl-5,10-dioxo-5,10-dihydro-4H-benzo[g]chromene-3-carboxylates, benzylamine and triethyl orthoformate under solvent- and catalyst-free conditions. All the new compounds were screened for their antiproliferative activity against two colorectal-cancer-cell lines. The results showed that the compounds 3-benzyl-5-phenyl-3,5-dihydro-4H-benzo[6,7]chromeno[2,3-d]pyrimidine-4,6,11-trione (3a) and 3-benzyl-5-(3-hydroxyphenyl)-3,5-dihydro-4H-benzo[6,7]chromeno[2,3-d]pyrimidine-4,6,11-trione (3g) exhibited the most potent balanced inhibitory activity against human LoVo and HCT-116 cancer cells. 相似文献
8.
Staudinger–Vilarassa reaction versus Huisgen reaction for the control of surface hydrophobicity and water adhesion
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Guilhem Godeau Jessica N'Na Emna El Kout Rawia Ben Trad Thierry Darmanin Mejda El Kateb Mohammed Beji Frédéric Guittard 《先进技术聚合物》2016,27(8):993-998
Surface modifications are keys for a great number of applications. In order to perfectly control the surface properties, it is important to control the modification pathways. Two general pathways can be described in order to introduce modification on surfaces: the post‐strategies and the ante‐strategies. In this work, we focus on the comparison between the Huisgen and the Staudinger–Vilarrasa reaction for both post‐surface and ante‐surface modifications. Here, we focused on the possibility to use both two reactions to obtain superhydrophobic and oleophobic properties. This work includes monomer synthesis, surface modifications with alkyl, aryl or perfluoroalkyl chain. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
Hatem Samaali Fehmi Najar Slim Choura Ali H. Nayfeh Mohamed Masmoudi 《Nonlinear dynamics》2011,63(4):719-734
In this paper, we propose the design of an ohmic contact RF microswitch with low voltage actuation, where the upper and lower
microplates are displaceable. We develop a mathematical model for the RF microswitch made up of two electrostatically actuated
microplates; each microplate is attached to the end of a microcantilever. We assume that the microbeams are flexible and that
the microplates are rigid. The electrostatic force applied between the two microplates is a nonlinear function of the displacements
and applied voltage. We formulate and solve the static and eigenvalue problems associated with the proposed microsystem. We
also examine the dynamic behavior of the microswitch by calculating the limit-cycle solutions. We discretize the equations
of motion by considering the first few dominant modes in the microsystem dynamics. We show that only two modes are sufficient
to accurately simulate the response of the microsystem under DC and harmonic AC voltages. We demonstrate that the resulting
static pull-in voltage and switching time are reduced by 30 and 45%, respectively, as compared to those of a single microbeam-microplate
RF-microswitch. Finally, we investigate the global stability of the microswitch using different excitation conditions. 相似文献
10.
Katalin Szabo Bernadette-Emke Teleky Floricuta Ranga Ioana Roman Hattab Khaoula Emna Boudaya Amina Ben Ltaief Wael Aouani Mangkorn Thiamrat Dan Cristian Vodnar 《Molecules (Basel, Switzerland)》2022,27(12)
The recovery of bioactive compounds from agro-industry-derived by-products sustains circular economy principles by encouraging maximized recycling and minimized waste. Tomato processing by-products are abundant in carotenoids, which have several health-promoting properties, and their reintegration into functional food products represents a major interest for scientists and manufacturers. In the present study, carotenoids were recovered from tomato processing by-products based on the principles of green chemistry by using generally recognized as safe (GRAS) solvents, freeze-drying as pretreatment, and ultrasound in the recovery procedure. Spectrophotometric measurements and HPLC were used to identify and quantify total and individual carotenoids from the extracts. The highest values for lycopene (1324.89 µg/g dw) were obtained when ethyl lactate was applied as a solvent, followed by ethyl acetate with slightly smaller differences (1313.54 µg/g dw). The extracts obtained from freeze-dried samples presented significantly lower amounts of lycopene, indicating that carotenoids are highly susceptible to degradation during lyophilization. Flaxseed, grape seed, and hempseed oils were enriched with carotenoids and their rheological measurements showed favorable viscoelastic properties, especially hempseed and flaxseed oil, with viscosity under 50 mPa·s. Considering the results and the economic perspective of carotenoid recovery from tomato processing by-products, ethyl acetate is suitable, sustainable, and environmentally friendly for carotenoid extraction. 相似文献