排序方式: 共有74条查询结果,搜索用时 15 毫秒
41.
Ali Oubella Abdoullah Bimoussa Abdellah Nait Oussidi Mourad Fawzi Aziz Auhmani Hamid Morjani Abdelkhalek Riahi Mhamed Esseffar Carol Parish Moulay Youssef Ait Itto 《Molecules (Basel, Switzerland)》2022,27(3)
Aseries of novel 1,4-disubstituted 1,2,3-triazoles were synthesized from an (R)-carvone terminal alkyne derivative via a Cu (I)-catalyzed azide–alkyne cycloaddition reaction using CuSO4,5H2O as the copper (II) source and sodium ascorbate as a reducing agent which reduces Cu (II) into Cu (I). All the newly synthesized 1,2,3-triazoles 9a–h were fully identified on the basis of their HRMS and NMR spectral data and then evaluated for their cell growth inhibition potential by MTS assay against HT-1080 fibrosarcoma, A-549 lung carcinoma, and two breast adenocarcinoma (MCF-7 and MDA-MB-231) cell lines. Compound 9d showed notable cytotoxic effects against the HT-1080 and MCF-7 cells with IC50 values of 25.77 and 27.89 µM, respectively, while compound 9c displayed significant activity against MCF-7 cells with an IC50 value of 25.03 µM. Density functional calculations at the B3LYP/6-31G* level of theory were used to confirm the high reactivity of the terminal alkyne as a dipolarophile. Quantum calculations were also used to investigate the mechanism of both the uncatalyzed and copper (I)-catalyzed azide–alkyne cycloaddition reaction (CuAAC). The catalyzed reaction gives complete regioselectivity via a stepwise mechanism streamlining experimental observations. The calculated free-energy barriers 4.33 kcal/mol and 29.35 kcal/mol for the 1,4- and 1,5-regioisomers, respectively, explain the marked regioselectivity of the CuAAC reaction. 相似文献
42.
Yahi N. Azzaz Y. Ameri M. Benouis M. Bensaid D. Arbouche O. Yamani M. Moulay N. 《Physics of the Solid State》2020,62(3):472-479
Physics of the Solid State - The magnetic stability and electronic properties of the FeO compound are investigated using the framework of an all-electron full-potential linearized augmented-plane... 相似文献
43.
Moulay Taïb Belghiti Boutayeb El Ammari Laurent P. Gendre 《Comptes Rendus Mathematique》2018,356(11-12):1125-1130
We study the problem of global approximation by polynomials in Whitney -flat jet classes on irregular compacts of . 相似文献
44.
45.
Kheong Sann Chan Elidrissi Moulay Rachid Kwaku Eason Rathnakumar Radhakrishnan Kim Keng Teo 《Journal of magnetism and magnetic materials》2012,324(3):336-343
Shingled writing (SW) and two-dimensional magnetic recording (TDMR) are two complementary candidate technologies proposed to extend the life of magnetic recording. SW enables the writing of narrow tracks with a wider writer by shingling the tracks; each track partially overlaps the preceding track leaving only a fraction of that track on the medium. TDMR is the companion technology to SW that enables reading of narrower tracks with a wider reader. In this work we compare the performances of 1D and 2D detectors in the shingled writing environment, using both comprehensive channel models and spin-stand readback. 相似文献
46.
Hossni Ziyat Moulay Youssef Ait Itto Mustapha Ait Ali Abdellah Karim Abdelkhalek Riahi Jean-Claude Daran 《Journal of chemical crystallography》2011,41(3):338-342
Abstract
The title compounds C11H16Cl2O3 (III) and C11H16Br2O3 (IV) have been prepared from (S)-Limonen. Their crystal structure and absolute configuration have been determined by X-ray analysis which confirmed the 1′S absolute configuration at the cyclopropyl moiety, in agreement with the known absolute configuration of the starting material. Both (III) and (IV) are orthorhombic, space group P212121 with a = 7.2558(4) ? (for III) 7.4058(6) ? (for IV), b = 9.7885(5) ? (for III) 9.7459(7) ? (for IV), c = 17.7551(10) ? (for III) 18.0354(14) ? (for IV), α = 90°, β = 90°, γ = 90° and Z = 4. 相似文献47.
In an epidemiological model, time spent in one compartment is often modeled by a delay in the model. In general the presence of delay in differential equations can change the stability of an equilibrium to instability and causes the appearance of oscillatory solutions.In this paper we consider a SIS epidemiological model with demographic effects: birth, mortality and mortality caused by infection. The delay is the period of infection. We define the concept of oscillation in the sense that solutions of the model studied fluctuate around a steady state. Our goal is to show that in this model, there are oscillating solutions for certain parameters values. We determine a large set of initial data for which solutions of this model are slowly oscillating. 相似文献
48.
Jin GB Ringe E Long GJ Grandjean F Sougrati MT Choi ES Wells DM Balasubramanian M Ibers JA 《Inorganic chemistry》2010,49(22):10455-10467
Black prisms of UFeS(3) and UFeSe(3) have been synthesized by solid-state reactions of U, Fe, and S or Se with CsCl as a flux at 1173 K. The structure of these isostructural compounds consists of layers of edge- and corner-sharing FeS(6) or FeSe(6) octahedra that are separated by layers of face- and edge-sharing US(8) or USe(8) bicapped trigonal prisms. The isomer shifts in the iron-57 M?ssbauer spectra of both UFeS(3) and UFeSe(3) are consistent with the presence of high-spin iron(II) ions octahedrally coordinated to S or Se. The XANES spectra of UFeS(3) and UFeSe(3) are consistent with uranium(IV). Single-crystal magnetic susceptibility measurements along the three crystallographic axes of UFeSe(3) reveal a substantial magnetic anisotropy with a change of easy axis from the a-axis above 40 K to the b-axis below 40 K, a change that results from competition between the iron(II) and uranium(IV) anisotropies. The temperature dependence of the magnetic susceptibility along the three axes is characteristic of two-dimensional magnetism. A small shoulder-like anomaly is observed in the magnetic susceptibilities along the a- and b-axes at 96 and 107 K, respectively. Below 107 K, the iron-57 M?ssbauer spectra of UFeS(3) and UFeSe(3) show that the iron nuclei experience a magnetic hyperfine field that results from long-range magnetic ordering of at least the iron(II) magnetic moments because the field exhibits Brillouin-like behavior. Below 40 K there is no significant change in the M?ssbauer spectra as a result of change in magnetic anisotropy. The complexity of the iron-57 M?ssbauer spectra and the temperature and field dependencies of the magnetic properties point toward a complex long-range magnetic structure of two independent iron(II) and uranium(IV) two-dimensional sublattices. The temperature dependence of the single-crystal resistivity of UFeSe(3) measured along the a-axis reveals semiconducting behavior between 30 and 300 K with an energy gap of about 0.03 eV below the 53 K maximum in susceptibility, of about 0.05 eV between 50 and 107 K, and of 0.03 eV above 107 K; a negative magnetoresistance was observed below 60 K. 相似文献
49.
Moulay Tahar Sougrati Malick Jean Samuel Jouen Charly Vaudolon Béatrice Hannoyer 《Hyperfine Interactions》2012,211(1-3):83-97
The operation of a gas counter, designed for Conversion Electron M?ssbauer Spectroscopy measurement at low temperature, has been investigated. The experimental setup is described and tested with two pure gases, He and Ne, and two mixtures, He-5%CH4 and He-5%N2. The impacts on the counter performances of the applied voltage, the gas composition and pressure as well as the gas renewing are investigated between 41?K and 300?K. This investigation is made using 119Sn M?ssbauer source and metallic tin absorber. The appropriate operating conditions of the present counter have been established for temperatures down to 41?K for both pure gases, and 61 and 85?K for He-5%N2 and He-5%CH4 respectively. 相似文献
50.
Fatima Mzyène Saâd Moulay Kheireddine Bal Fatiha Madi 《Journal of inclusion phenomena and macrocyclic chemistry》2018,92(3-4):381-394
Hydroxyapatite (HAp) and hydroxyapatite/chitosan/β-cyclodextrin (HAp/CS/β-CD) nanoparticles were successfully prepared in the modified simulated body fluid (SBF) solution at the physiological conditions (pH 7.4, temperature?=?37 °C). CS/β-CD nanoparticles acted as templates for the synthesis of HAp/CS/β-CD nanoparticles to improve the nanoarchitecture of HAp and its crystallinity.The nanoparticles were characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Kneading and coprecipitation methods were applied to prepare the inclusion complex involving β-CD and p-THPP (5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin), a photosensitizer for anti-cancer drugs. The 1:1 stoichiometric ratio of the formed inclusion complex was characterized by a formation constant of 7.216?×?102 mol?1 dm3 and analyzed by 1H NMR, FTIR, and UV–Vis. The p-THPP delivery release in vitro was in this order: HAp/CS/β-CD?<?CS/β-CD?<?<?HAp/β-CD?<?β-CD, hinting at a better controlled release by HAp/CS/β-CD nanoparticles. 相似文献