排序方式: 共有47条查询结果,搜索用时 31 毫秒
1.
El-Hendawy Ahmed M. Alqaradawi Siham Y. Al-Madfa Homaid A. 《Transition Metal Chemistry》2000,25(5):572-578
The new complexes [RuIIIbpyL2](PF6) and [RuIIIbpyLCl2] [bpy = 2,2-bipyridine; HL = acetylacetone, trifluoroacetylacetone, benzoylacetone (Hbac), tropolone or maltol; HL = Hbac or dibenzoylmethane) have been prepared and characterized by spectroscopy. Their redox behaviour was studied by cyclic voltammetry. They effectively catalyze the oxidation of alcohols, alkanes and primary aromatic amines. 相似文献
2.
Siham El FangourAlexandre Guy Jean-Pierre VidalJean-Claude Rossi Thierry Durand 《Tetrahedron letters》2003,44(10):2105-2108
The first synthesis of the two enantiomers of phytoprostane F1 methyl ester 1 and 2 is described using the syn-anti-syn alcoxy ester 3 as starting material. 相似文献
3.
Buffi N Merulla D Beutier J Barbaud F Beggah S van Lintel H Renaud P van der Meer JR 《Lab on a chip》2011,11(14):2369-2377
Contamination with arsenic is a recurring problem in both industrialized and developing countries. Drinking water supplies for large populations can have concentrations much higher than the permissible levels (for most European countries and the United States, 10 μg As per L; elsewhere, 50 μg As per L). Arsenic analysis requires high-end instruments, which are largely unavailable in developing countries. Bioassays based on genetically engineered bacteria have been proposed as suitable alternatives but such tests would profit from better standardization and direct incorporation into sensing devices. The goal of this work was to develop and test microfluidic devices in which bacterial bioreporters could be embedded, exposed and reporter signals detected, as a further step towards a complete miniaturized bacterial biosensor. The signal element in the biosensor is a nonpathogenic laboratory strain of Escherichia coli, which produces a variant of the green fluorescent protein after contact to arsenite and arsenate. E. coli bioreporter cells were encapsulated in agarose beads and incorporated into a microfluidic device where they were captured in 500 × 500 μm(2) cages and exposed to aqueous samples containing arsenic. Cell-beads frozen at -20 °C in the microfluidic chip retained inducibility for up to a month and arsenic samples with 10 or 50 μg L(-1) could be reproducibly discriminated from the blank. In the 0-50 μg L(-1) range and with an exposure time of 200 minutes, the rate of signal increase was linearly proportional to the arsenic concentration. The time needed to reliably and reproducibly detect a concentration of 50 μg L(-1) was 75-120 minutes, and 120-180 minutes for a concentration of 10 μg L(-1). 相似文献
4.
Syntheses of the enantiomerically pure phytoprostanes B(1) type I and II are described starting from furfural and n-propylfuran. Key steps include the preparation of the Freimanis (+/-)-hydroxycyclopentenone and Wittig coupling using chiral phosphonium salts. 相似文献
5.
Dehouche Siham Hamadouche Mhamed 《International Journal of Satellite Communications and Networking》2018,36(4):332-351
Global navigation satellite system applications based on high sensitivity and weak‐signal acquisition is a difficult task and has become an important research area. Algorithms and techniques are proposed, principally those associated to cases of limited global navigation satellite system signal availability. Collective detection is a new technique that seems to offer better solutions in a such situation. This paper presents a performance analysis of GPS L1 noncoherent acquisition via collective detection based on the systematic and efficient collective acquisition algorithm in the Rayleigh fading channel, firstly in the case of a fixed threshold detection and secondly in the case of adaptive threshold detection based on a constant false alarm rate. To compare these methods with traditional acquisition schemes, we develop detection and false alarm probability analytic expressions. 相似文献
6.
AlQaradawi SY Nour EM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(3):908-911
The interaction of the interesting polynitrogen cyclic base 1,4,7-trimethyl-1,4,7-triazacyclononane (TMTACN) with the sigma-acceptor iodine and pi-acceptors tetracyanoethylene (TCNE), 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetrachloro-p-benzoquinone (chloranil) have been studied spectrophotometrically and cyclic voltametrically in chloroform at 20 degrees C. Based on the obtained data, the formed charge-transfer complexes were formulated as [(TMTACN)I](+).I(3)(-), [(TMTACN)(TCNE)(5)], [(TMTACN)(TCNQ)(3)] and [(TMTACN)(chloranil)(3)] where the stoichiometry of the reactions, donor:acceptor molar ratios, were shown to equal 1:2 for iodine complex, 1:3 for chloranil and TCNQ complexes and 1:5 for TCNE complex. 相似文献
7.
Summary: This contribution will focus on the elaboration and characterizations of new materials with optimal properties as interpolymer complexes, upon mixing poly (styrene-co-acrylic acid containing 18, 27 and 32 mol % of acrylic acid (SAA-x) and poly (N,N-dimethylacrylamide) (PDMA), through the control of the densities, strength, self-association and accessibility of the interacting species. These elaborated interpolymer complexes, of different structures, investigated by DSC and TGA, exhibited a significant improved thermal stability. Their DSC analysis showed that all these materials showed one composition-dependence glass transition temperature Tg, indicating the formation of a single homogeneous phase. The different behaviors of Tg-initial composition observed with these systems were analyzed by the approaches of Kwei and Brostow et al., recently developed. The specific interactions that occurred within the elaborated materials were evidenced qualitatively by ATR/FTIR spectroscopy, from the appearance of new bands in the 1800–1550 cm−1 region. 相似文献
8.
Siham Benadji Pierre Eloy Alexandre Léonard Bao-Lian Su Chérifa Rabia Eric M. Gaigneaux 《Comptes Rendus Chimie》2012,15(8):658-668
The H4PMo11VO40 heteropolyacid (HPA) was supported at 30 wt.% by the dry impregnation method on HMS, CMI-1 and SBA-15 mesoporous materials. The state of the HPA and those of the supports were examined by nitrogen physisorption, X-ray diffraction, (DR) FT–IR and X-ray photoelectron spectroscopies, thermal analysis (TG–ATD) and scanning electron microscopy (SEM). The effect of support on the catalytic behavior of H4PMo11VO40 was studied in the propene oxidation at 350 °C. It was shown that the presence of H4PMo11VO40, modifies the textural properties of mesoporous materials (decrease of surface area) without destroying their structure. The interaction support–heteropolyacid leads to the formation of (SiOH2+)(H3PMo11VO40?) surface species more stable than H4PMo11VO40 species and that appear to be the active sites in the propene oxidation. 相似文献
9.
Shakya Anshul Chikhale Rupesh V. Bhat Hans Raj Alasmary Fatmah Ali Almutairi Tahani Mazyad Ghosh Surajit Kumar Alhajri Hassna Mohammed Alissa Siham A. Nagar Shuchi Islam Md Ataul 《Molecular diversity》2022,26(1):265-278
Molecular Diversity - Transmembrane protease serine-2 (TMPRSS2) is a cell-surface protein expressed by epithelial cells of specific tissues including those in the aerodigestive tract. It helps the... 相似文献