排序方式: 共有44条查询结果,搜索用时 15 毫秒
1.
Reda M. Fikry Nabila A. Ismael Adel A. El-Bahnasawy Aymen A. Sayed El-Ahl 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1227-1236
Several new 2-arylidinoamino-4-(3-coumaryl)thiazole derivatives were synthesized via the reaction of 2-amino-4-(coumaryl)thiazole with aromatic aldehydes and other reagents. Structural elucidations were based on elementary analysis and spectral data studies. 相似文献
2.
Eleonora Truzzi Mohamed Aymen Chaouch Gaia Rossi Lorenzo Tagliazucchi Davide Bertelli Stefania Benvenuti 《Molecules (Basel, Switzerland)》2022,27(5)
The main focus of the current research was the characterization of the by-products from the steam distillation of Lavandula angustifolia Mill. (LA) and Lavandula x intermedia Emeric ex Loisel (LI) aerial parts, as they are important sources of bioactive compounds suitable for several applications in the food, cosmetic, and pharmaceutical industries. The oil-exhausted biomasses were extracted and the total polyphenol and flavonoid contents were, respectively, 19.22 ± 4.16 and 1.56 ± 0.21 mg/g for LA extract and 17.06 ± 3.31 and 1.41 ± 0.10 mg/g for LI extract. The qualitative analysis by liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS) revealed that both the extracts were rich in phenolic acids and glycosylated flavonoids. The extracts exhibited radical scavenging, chelating, reducing activities, and inhibitory capacities on acetylcholinesterase and tyrosinase. The IC50 values against acetylcholinesterase and tyrosinase were, respectively, 5.35 ± 0.47 and 5.26 ± 0.02 mg/mL for LA, and 6.67 ± 0.12 and 6.56 ± 0.16 mg/mL for LI extracts. In conclusion, the oil-exhausted biomasses demonstrated to represent important sources of bioactive compounds, suitable for several applications in the food, cosmetic, and pharmaceutical industries. 相似文献
3.
Two synthetic protocols leading to novel γ-aminophosphonate and phosphine oxide derivatives, by reductive amination of γ-phosphonylketones, are reported. The first method involved a two-step procedure. Imine intermediates were first isolated from the p-toluenesulfonic acid-catalyzed reaction of primary amines with γ-ketophosphonates and phosphine oxides, then reduced with NaBH4 in refluxing ethanol. The second method consists of a one-pot procedure which includes the condensation of γ-ketophosphonates and phosphine oxides with primary amines, in the presence of molecular sieves, followed by reduction with NaBH4. These methods offer significant advantages over prior reports, such as efficiency, generality, and good yields. Furthermore, they are green protocols avoiding hazardous hydrides and solvents. 相似文献
4.
In this research article, we work with the notion of the measures of noncompactness in order to establish some results concerning the essential pseudospectra of closed, densely defined linear operators in the Banach space. We start by giving a refinement of the definition of the essential pseudospectra by means of the measure of noncompactness, and we give sufficient conditions on the perturbed operator to have its invariance. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
Let ? n be the (2n + 1)-dimensional Heisenberg group, and let T n be the n-dimensional torus acting on ? n by automorphisms. In this paper, we describe the space of admissible coadjoint orbits of the Heisenberg motion group G n = T n ? ? n and we determine the topology of this space. We show that the bijection between the unitary dual ? n of G n and its admissible coadjoint orbit space is a homeomorphism. 相似文献
6.
Mashhour Al-Ali Bani-Ata Christoph Hering Anni Neumann Aymen Rawashdeh 《Journal of Geometry》2007,86(1-2):1-5
The purpose of this paper is to prove the existence of semifields of order q
4 for any odd prime power q = pr, q > 3, admitting a free automorphism group isomorphic to Z
2 × Z
2. 相似文献
7.
A homemade instrument for the measurement of oxygen concentration in aqueous solutions measures the decay rate of the phosphorescence of a Pd-porphyrin complex (phosphor) dissolved in the solution, which is flashed every 0.1 s with 630 nm light. The concentration of O2 is a linear function of the decay rate. The instrument is used to study the reaction of dithionite (S2O42-) with O2 at 25 degrees C and 37 degrees C. It is found that the ratio of dithionite to oxygen consumed in the reaction is 1.2 +/- 0.2 at 25 degrees C and 1.7 +/- 0.1 at 37 degrees C, suggesting a temperature-dependent stoichiometry. At both temperatures, the initial rate of O2 consumption, -d[O2]/dt, is found to be 1/2 order in S2O42- and first order in O2. This finding is consistent with a previously proposed mechanism: S2O42- <--> 2SO2- comes to a rapid equilibrium, and SO2- reacts with O2 in the rate-determining step. 相似文献
8.
Dorra Aissaoui-Zid Mohamed-Chiheb Saada Wassim Moslah Marie Potier-Cartereau Aude Lemettre Houcemeddine Othman Marc Gaysinski Zaineb Abdelkafi-Koubaa Soumaya Souid Naziha Marrakchi Christophe Vandier Khadija Essafi-Benkhadir Najet Srairi-Abid 《Molecules (Basel, Switzerland)》2021,26(24)
Glioblastoma is an aggressive cancer, against which medical professionals are still quite helpless, due to its resistance to current treatments. Scorpion toxins have been proposed as a promising alternative for the development of effective targeted glioblastoma therapy and diagnostic. However, the exploitation of the long peptides could present disadvantages. In this work, we identified and synthetized AaTs-1, the first tetrapeptide from Androctonus australis scorpion venom (Aa), which exhibited an antiproliferative effect specifically against human glioblastoma cells. Both the native and synthetic AaTs-1 were endowed with the same inhibiting effect on the proliferation of U87 cells with an IC50 of 0.56 mM. Interestingly, AaTs-1 was about two times more active than the anti-glioblastoma conventional chemotherapeutic drug, temozolomide (TMZ), and enhanced its efficacy on U87 cells. AaTs-1 showed a significant similarity with the synthetic peptide WKYMVm, an agonist of a G-coupled formyl-peptide receptor, FPRL-1, known to be involved in the proliferation of glioma cells. Interestingly, the tetrapeptide triggered the dephosphorylation of ERK, p38, and JNK kinases. It also enhanced the expression of p53 and FPRL-1, likely leading to the inhibition of the store operated calcium entry. Overall, our work uncovered AaTs-1 as a first natural potential FPRL-1 antagonist, which could be proposed as a promising target to develop new generation of innovative molecules used alone or in combination with TMZ to improve glioblastoma treatment response. Its chemical synthesis in non-limiting quantity represents a valuable advantage to design and develop low-cost active analogues to treat glioblastoma cancer. 相似文献
9.
The Ramanujan Journal - We investigate some basic analytic properties of the $$L^2$$ -holomorphic automorphic functions on a g-complex vector space associated with isotropic discrete subgroups... 相似文献
10.
Periodica Mathematica Hungarica - In this paper, we define the localization operator associated with the Riemann–Liouville operator, and show that it is not only bounded, but it is also in... 相似文献