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131.
Abdellah Aghraz Ambrogina Albergamo Qada Benameur Andrea Salvo Mustapha Larhsini Mohamed Markouk 《Natural product research》2020,34(1):63-70
AbstractAim of this study was to evaluate polyphenols and major and trace elements of Cladanthus arabicus and Bubonium imbricatum, along with their in vitro antibacterial activity against six multidrug resistant Enterobacteriaceae (Escherichia coli S33/16, E. coli S34/16, Proteus mirabilis S32/16, Klebsiella pneumoniae S12/16, Enterobacter cloacae S5/16, and Salmonella sp S12/14). UV spectrophotometry, ultra-high-performance liquid chromatography coupled to mass spectrometry and inductively coupled plasma mass spectrometry were used to evaluate total polyphenol content, quali-quantitative profile of single polyphenols and inorganic elements of the extract. The antibacterial activity was investigated by standard methods. Twelve polyphenols were identified in both plants and these were more concentrated in B. imbricatum than C. arabicus extracts. High levels of minerals, essential trace elements and tolerable levels of heavy metals (Cd, As and Pb) were found. Furthermore, the extracts showed also a strong in vitro antibacterial activity, particularly versus E. coli S33/16 (MIC, 0.125?mg ml?1). 相似文献
132.
Selective Detection of Dopamine in Presence of Ascorbic Acid by Use of Glassy‐Carbon Electrode Modified with Amino‐β‐Cyclodextrin and Carbon Nanotubes
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Aymen Gaied Nejmeddine Jaballah Moncef Tounsi Mohamed Braiek Nicole Jaffrezic‐Renault Mustapha Majdoub 《Electroanalysis》2014,26(12):2747-2753
A glassy carbon electrode modified with per‐6‐amino‐β‐cyclodextrin (β‐CDNH2) and functionalized single‐walled carbon nanotubes (SWCNT‐COOH) was elaborated. This structure was investigated for the detection of dopamine acid (DA) in presence of ascorbic acid (AA). The sensor behavior was studied by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The analysis results show that the electrode modification with CD derivative improves the sensitivity and selectivity of the DA recognition; the electrochemical response was further improved by introduction of SWCNT‐COOH. The sensor shows good and reversible linear response toward DA within the concentration range of 7×10?7–10?4 M with a detection limit of 5×10?7 M. 相似文献
133.
Mustapha Raïssouli 《Linear and Multilinear Algebra》2019,67(2):213-220
Let T and S be two self-adjoint positive invertible operators of a complex Hilbert space H. In this paper, we investigate some inequalities involving the quadratic forms of the weighted arithmetic and harmonic means of T and S. Application for operator entropies is also discussed. 相似文献
134.
Mustapha Hellou 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,25(1):642-657
The positive inversion transformation applied to a
two-dimensional Stokes flow around bodies leads alike to a Stokes
flow. This fact can be exploited to find new two-dimensional
Stokes flow solutions around inverse bodies. Some features of this
method, such as the relations between the reference and inverse
fluid velocity fields, are presented followed by an application to
examples of cellular flow between two parallel plates induced by
rotating or translating cylinder. Thus hydrodynamic
characteristics of flow around circular bodies obtained by
inversion of the plates are straightforward deduced. Typical fluid
flow patterns around two circular cylinders in contact placed in
the centre of a rotating or a translating circular cylinder are
thus illustrated. 相似文献
135.
We show that the electrically charged wormhole soliton solution of sourceless five-dimensional general relativity is classically stable against radial perturbations, except in the special case of a massless soliton.On leave of absence from: Département de Physique Théorique, Université de Constantine, Constantine, Algeria 相似文献
136.
This paper studies a stochastic linear quadratic (LQ) control problem in the infinite time horizon with Markovian jumps in parameter values. In contrast to the deterministic case, the cost weighting matrices of the state and control are allowed to be indinifite here. When the generator matrix of the jump process – which is assumed to be a Markov chain – is known and time-invariant, the well-posedness of the indefinite stochastic LQ problem is shown to be equivalent to the solvability of a system of coupled generalized algebraic Riccati equations (CGAREs) that involves equality and inequality constraints. To analyze the CGAREs, linear matrix inequalities (LMIs) are utilized, and the equivalence between the feasibility of the LMIs and the solvability of the CGAREs is established. Finally, an LMI-based algorithm is devised to slove the CGAREs via a semidefinite programming, and numerical results are presented to illustrate the proposed algorithm. 相似文献
137.
Tewfik Bouchaour Fr d rick Roussel Jean-Marc Buisine Xavier Coqueret Mustapha Benmouna Ulrich Maschke 《Liquid crystals》2003,30(4):487-491
The thermophysical properties of mixtures of poly (2-phenoxyethylacrylate) and 4-cyano-4'-pentyl-biphenyl, 5CB, are investigated using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The polymer has a molar mass M w = 181 000 g mol -1 ; the low molecular mass liquid crystal exhibits a nematic to isotropic transition at 35.3°C and crystallizes below 23°C. The phase diagram exhibits miscibility gaps in certain regions of temperature and composition where coexisting nematic and isotropic phases are found. From a practical point of view when considering the electro-optical applications of these systems, it proves to be useful to know precisely the amount of small liquid crystal molecules dissolved in the polymer matrix and the concentration of polymer in the nematic phase. The former quantity has a mechanical impact due to a plasticizing effect, an optical impact since it changes the polymer refractive index, while the polymer in the nematic phase shifts the transition temperatures influencing the electro-optical response of the liquid crystal. The present work addresses these important aspects using POM and DSC. 相似文献
138.
Nan Huang Tiansheng Wang Mustapha Soukri Rakesh Ganorkar Bruce Deker Jose Madalengoitia 《Tetrahedron》2008,64(42):9850-9856
Condensation of methyl 3-benzyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole-5-carboxylate (3) with methyl Z-4-formylhex-3-enoate (6) gave cis-fused dimethyl 5-benzyl-4-ethyl-2,4a,5,6,7,12-hexahydro-1H-benzo[2,3]azepino[4,5-b]indole-2,12b-dicarboxylate and its trans-fused diastereomer. Selective reduction of the less hindered ester group with sodium borohydride to an alcohol ester, tosylation, debenzylation, and cyclization gave racemic catharanthine (1). 相似文献
139.
Mustapha Mokhtar-Kharroubi 《Journal of Evolution Equations》2008,8(2):327-352
We deal with streaming operators T
H
defined in L
1 spaces by the directional derivative with positive boundary operator H of norm 1 relating the incoming and outgoing fluxes. It is known that T
H
need not be a generator but there exists a contraction semigroup generated by an extension A of T
H
. This paper deals with the total mass carried by individual trajectories {e
tA
f; t ≥ 0} for nonnegative initial data f and related topics. In particular, our analysis covers the problem of (the lack of) stochasticity of {e
tA
; t ≥ 0} for conservative boundary operator H.
相似文献
140.
Tatiana Campos-Malpartida Ferenc Joó Ágnes Kathó Mustapha Saoud 《Journal of organometallic chemistry》2008,693(3):468-474
The process of catalytic isomerisation of various allylic alcohols (alk-1-en-3-ols) into saturated ketones under mild conditions is reported. The water-soluble Na4[{RuCl2(mtppms)2}2] complex, previously reported by us as a precursor to very active hydrogenation catalysts was also found an active catalyst of the redox isomerisation of allylic alcohols in aqueous media. The new Na[Ru(CO)Cp(mtppms)2] as well as Na4[{RuCl(μ-Cl)(CCCPh2)(mtppms)2}2] and Na2[RuClCp(mtppms)2] also showed good to excellent catalytic activities for redox isomerisations in aqueous systems at 50-80 °C under inert atmosphere. 相似文献