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排序方式: 共有169条查询结果,搜索用时 31 毫秒
51.
Amel Ben Jalloul Nourhene Ayadi Amira Klai Manef Abderrabba 《Molecules (Basel, Switzerland)》2022,27(12)
This study aimed to evaluate the effects of thyme (Thymus vulgaris L.), rosemary (Rosmarinus officinalis L.), and ammoides (Ammoidespusilla L.) aqueous extracts supplementation on the quality of heat-treated (55, 65, and 75 °C) raw milk (sample lots: A, B, and C) and cold-stored pasteurized milk (lot D). The three herbs have shown rich polyphenol contents (32.65–104.23 mgGAE/g), relevant antioxidant capacity, and high caffeic and rosmarinic acids and catechin contents. A significant reduction in psychrotrophic and total viable bacteria counts (PC and TVC) was attained following milk extract supplementation in both experiments. Monitoring PC and TVC counts in sample lots (A, B, and C) has revealed a significant improvement in extracts’ effectiveness in reducing the TVC count with the increment of temperature. The highest reductions of PC and TVC counts were achieved, respectively, in samples treated with thyme and rosemary in (lots: A, B, and C) and in samples treated with ammoides and thyme in (lot D). Thyme extract showed the highest milk serum DPPH scavenging activity (74.84% at 0.1 mg/mL) and induced a significant Listeria monocytogenes growth inhibition (>1 Log cycle). The sensory evaluation of supplemented milk has shown good consumer acceptability of ammoides-supplemented milk, quite similar to the control sample. 相似文献
52.
Amel Rahmoun Djamila Benmerzouk Bedreddine Ainseba 《Mathematical Methods in the Applied Sciences》2016,39(8):1924-1934
In this paper, a bifurcation solution's analysis is proposed for an HIV‐1 within the host model around its chronic equilibrium point, this is carried out based on Lyapunov–Schmidt approach. It is shown that the coefficient b, which represents the healthy CD4+ T‐cells growth rate, is a bifurcation parameter; this means that the rate of multiplication of healthy cells can have serious effects on the qualitative dynamical properties and structural stability of the infection evolution dynamics. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
53.
Function vector synchronization based on fuzzy control for uncertain chaotic systems with dead‐zone nonlinearities
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In this article, a fuzzy adaptive control scheme is designed to achieve a function vector synchronization behavior between two identical or different chaotic (or hyperchaotic) systems in the presence of unknown dynamic disturbances and input nonlinearities (dead‐zone and sector nonlinearities). This proposed synchronization scheme can be considered as a generalization of many existing projective synchronization schemes (namely the function projective synchronization, the modified projective synchronization, generalized projective synchronization, and so forth) in the sense that the master and slave outputs are assumed to be some general function vectors. To practically deal with the input nonlinearities, the adaptive fuzzy control system is designed in a variable‐structure framework. The fuzzy systems are used to appropriately approximate the uncertain nonlinear functions. A Lyapunov approach is used to prove the boundedness of all signals of the closed‐loop control system as well as the exponential convergence of the corresponding synchronization errors to an adjustable region. The synchronization between two identical systems (chaotic satellite systems) and two different systems (chaotic Chen and Lü systems) are taken as two illustrative examples to show the effectiveness of the proposed method. © 2015 Wiley Periodicals, Inc. Complexity 21: 234–249, 2016 相似文献
54.
Amel Hamdi Sara Jaramillo-Carmona Rocío Rodríguez-Arcos Ana Jimnez-Araujo Mokhtar Lachaal Najoua Karray-Bouraoui Rafael Guilln-Bejarano 《Molecules (Basel, Switzerland)》2021,26(11)
The phytochemical composition of leaves, stems, pericarps and rhizomes ethanolic extracts of Asparagus acutifolius were characterized by HPLC-DAD-MS. A. acutifolius samples contain at least eleven simple phenolics, one flavonon, two flavonols and six steroidal saponins. The stem extracts showed the highest total phenolic acid and flavonoid contents, where cafeic acid and rutin were the main compounds. No flavonoids were detected in the leaf, pericarp or rhizome while caffeic acid and ferulic acid were the predominant. Steroidal saponins were detected in the different plant parts of A. acutifolius, and the highest contents were found in the rhizome extracts. The stem extracts exhibited the highest antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) and the highest 2,2-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity was found in the pericarp extracts. The rhizome and leaf extracts showed a potent cytotoxic activity against HCT-116 and HepG2 cell lines. Moreover, the pericarp and rhizome extracts revealed a moderate lipase inhibitory activity. The leaf and rhizome extracts were screened for their antimicrobial activity against human pathogenic isolates. The leaf extract exhibited a powerful inhibitory activity against all the bacteria and fungi tested. 相似文献
55.
Amel Haouas Naoufel Ben Hamadi Moncef Msaddek 《Journal of heterocyclic chemistry》2015,52(6):1765-1768
In explorations of synthesis and chemistry of spiroheterocycles, we found that the reaction of 2‐diazopropane with arylidene‐benzofuran‐2(3H)‐one and arylidene‐benzofuran‐3(2H)‐one derivatives generated the spirocyclopropane products. In addition to the expected cycloadducts, an unexpected oxadiazole was formed in some cases. The structures of the obtained adducts have been assigned by means of spectroscopic methods. 相似文献
56.
Louaar S Achouri A Lefahal M Laouer H Medjroubi K Duddeck H Akkal S 《Natural product communications》2011,6(11):1603-1604
Six flavonoids, namely 6-methoxykaempferol (1), 6-methoxykaempferol 7-O-glucoside (2), kaempferol 7-O-glucoside (3), 6-methoxyluteolin (4), patuletin 7-O-glucoside (5), and hispidulin 7-O-glucoside (6), were isolated from a n-butanolic fraction of Centaurea microcarpa Coss et Dur. flowers. This work describes for the first time the phytochemical composition of this endemic Algerian plant. 相似文献
57.
First-principles calculations of the second-order optical response functions and the dielectric functions of urea [CO(NH(2))(2)] and some of its derivatives such as monomethylurea (H(2)NCONHCH(3), MMU), and N,N'-dimethylurea (H(3)CHNCONHCH(3), DMU) crystals are performed. On the basis of the density functional theory (DFT) in the local-density approximation (LDA), the highly accurate full-potential projected augmented wave (FP-PAW) method was used to obtain the electronic structure. Over a wide frequency range (0.0-10.0 eV), the dielectric constants and second-harmonic generation (SHG) susceptibilities of the urea crystal family have been obtained, and the results are in good agreement with the experimental values. The origin of the linear and nonlinear optical (NLO) properties of the urea crystal family has been analyzed by coupling the calculated electronic structure and optical spectrum. The prominent spectra of χ((2)) are successfully correlated with the dielectric function ε(ω) in terms of single-photon and double-photon resonances. The virtual electron (VE) and virtual hole (VH) processes have also been performed for the urea crystal family. From the research into the electron deformation density, crystal configuration, substitutional group, and so forth, it is found that the origin of the SHG of the urea crystal family is the charge transfer due to the strong "(?)push-pull" effect along the hydrogen bond, which favors a head-to-tail arrangement of the molecules and enhances the SHG response. The electron-donating substitutional group supplies more electrons to the electron-accepting group, and helps to form large dipoles in molecules. The influence on the NLO properties of the local symmetry of the substitutional group is also discussed in detail. 相似文献
58.
Ioana Varduca Enache Lucia Mutihac Amel Ben Othman Jacques Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(3-4):537-543
The native and methyl ester amino acids have been extracted by calix[4]azacrowns 1 (1,3-[ethylene-bis-aminocarbonylmethoxy)]-p-tert-butylcalix[4]arene) and 2 (1,3-[propylene-bis-aminocarbonylmethoxy)]-p-tert-butyl-calix[4]arene) from an aqueous phase into a chloroform phase and transported through a chloroform liquid membrane as ion pairs in the presence of picrate or tropaeolin 00 as counter ions aiming their separation. The amino acids under study exhibited good extractability by calix[4]azacrowns 1 and 2. Both receptors 1 and 2 showed good extractability towards amino acids under study. The results are discussed in term of correlation of structural properties of amino acids and calix[4]azacrowns involved in experiments. In this respect, the influence of chain length of receptors upon extraction and transport of amino acids, and the nature of anions used as counter ions are evaluated. 相似文献
59.
Saeed Ul Haq Raz Muhammad Afaf Khadr Alqorashi Muhammad Shafiullah Amir Sohail Amel Laref Muhammad Faizan 《International journal of quantum chemistry》2024,124(3):e27353
We investigated the magnetic and thermoelectric properties of REMoN3 (RE = La, Ce, Pr, Nd, Sm) perovskites using the full potential linearized augmented plane wave (FP-LAPW) method. To overcome the problem of underestimation of electronic interaction, we employed the DFT + U approach to accurately map the electronic structure of these compounds. Our study shows an increasing trend in the magnetic moments with the increasing number of unpaired electrons in RE. Among these compounds, SmMoN3 possesses a large magnetic moment, which is suitable for applications such as memory devices and sensors. Interestingly, all these perovskites display ferromagnetic behavior except CeMoN3, which exhibits an antiferromagnetic nature. Furthermore, our analysis indicates n-type thermoelectric behavior in all these materials. The compound, namely PrMoN3, exhibits a high figure of merit among REMoN3, which can be improved by modifying the lattice sites. 相似文献
60.