排序方式: 共有10条查询结果,搜索用时 15 毫秒
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Douaa Bekkai Yassine Oulad El Majdoub Hamid Bekkai Francesco Cacciola Natalizia Miceli Maria Fernanda Taviano Emilia Cav Tomader Errabii Roberto Lagan Vinci Luigi Mondello Mohammed LBachir El Kbiach 《Molecules (Basel, Switzerland)》2022,27(13)
This study aimed to investigate the phenolic profile and selected biological activities of the leaf and aerial extracts of three Ericaceae species, namely Erica multiflora, Erica scoparia, and Calluna vulgaris, collected from three different places in the north of Morocco. The phenolic composition of all extracts was determined by LC coupled with photodiode array and mass spectrometry detection. Among the investigated extracts, that of E. scoparia aerial parts was the richest one, with a total amount of polyphenols of 9528.93 mg/kg. Up to 59 phenolic compounds were detected: 52 were positively identified and 49 quantified—11 in C. vulgaris, 14 in E. multiflora, and 24 in E. scoparia. In terms of chemical classes, nine were phenolic acids and 43 were flavonoids, and among them, the majority belonged to the class of flavonols. The antioxidant activity of all extracts was investigated by three different in vitro methods, namely DPPH, reducing power, and Fe2+ chelating assays; E. scoparia aerial part extract was the most active, with an IC50 of 0.142 ± 0.014 mg/mL (DPPH test) and 1.898 ± 0.056 ASE/mL (reducing power assay). Further, all extracts were non-toxic against Artemia salina, thus indicating their potential safety. The findings attained in this work for such Moroccan Ericaceae species, never investigated so far, bring novelty to the field and show them to be valuable sources of phenolic compounds with interesting primary antioxidant properties. 相似文献
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Achouak Bekkai Belgacem Rebiai Mokhtar Kirane 《Mathematical Methods in the Applied Sciences》2019,42(6):1819-1830
In this paper, we are concerned with local existence and blowup of a unique solution to a time‐space fractional evolution equation with a time nonlocal nonlinearity of exponential growth. At first, we prove the existence and uniqueness of the local solution by the Banach contraction mapping principle. Then, the blowup result of the solution in finite time is established by the test function method with a judicious choice of the test function. 相似文献
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Kaoutar Ghomari Bekkai Messirdi 《Journal of Mathematical Analysis and Applications》2011,378(1):306-313
The goal of this paper is to present an explicit computation of the Birkhoff-Gustavson normal form in the 1:1, 1:2 and 1:3 resonances, by using the concept of Weyl quantization, especially when it is about the first terms. We use in particular the Weyl symbolic calculus and the abstract theorem of the quantum Birkhoff-Gustavson normal form in infinite dimension. 相似文献
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In this paper, we give an affirmative answer to Mbekhta's conjecture (Mbekhta, 1990 [13]) about the pseudo Fredholm operators in Hilbert space. As a consequence, we characterize pseudo Fredholm operators and we prove that the generalized Kato spectrum satisfies the spectral mapping theorem in the Hilbert spaces setting. 相似文献
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Siham Bekkai 《Discrete Applied Mathematics》2010,158(17):1888-1893
We bound the mean distance in a connected graph which is not a tree in terms of its order n and its girth g. On one hand, we show that the mean distance is at most if g is even and at most if g is odd. On the other hand, we prove that the mean distance is at least unless G is an odd cycle. This resolves two conjectures of AutoGraphiX. 相似文献
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Mathematical Notes - The main subject of this paper is the study of a general linear boundary-value problem with Drazin or right Drazin (respectively, left Drazin) invertible operators... 相似文献
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Siham Bekkai 《Discrete Applied Mathematics》2009,157(4):774-779
We show that a graph with minimum degree δ, independence number α≥δ and without isolated vertices, possesses a partition by vertex-disjoint cycles and at most α−δ+1 edges or vertices. 相似文献
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We study the spectral properties of general diatomic molecules near a scattering level. We prove that in the Born-Oppenheimer approximation, this study can be reduced to the one of a a matrix of semiclassical pseudodifferential operators. More precisely, we provide a link between the resonances of the molecule which are close enough to the real axis, and the discrete spectrum of this matrix (the principal symbol of which being made explicit via the electronic levels of the molecule). 相似文献
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In this paper, we define and study the left and the right generalized Drazin inverse of bounded operators in a Banach space. We show that the left (resp. the right) generalized Drazin inverse is a sum of a left invertible (resp. a right invertible) operator and a quasi-nilpotent one. In particular, we define the left and the right generalized Drazin spectra of a bounded operator and also show that these sets are compact in the complex plane and invariant under additive commuting quasi-nilpotent perturbations. Furthermore, we prove that a bounded operator is left generalized Drazin invertible if and only if its adjoint is right generalized Drazin invertible. An equivalent definition of the pseudo-Fredholm operators in terms of the left generalized Drazin invertible operators is also given. Our obtained results are used to investigate some relationships between the left and right generalized Drazin spectra and other spectra founded in Fredholm theory. 相似文献
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