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431.
Alketa Tarushi George Psomas Catherine P. Raptopoulou Vassilis Psycharis Dimitris P. Kessissoglou 《Polyhedron》2009
The novel neutral mononuclear zinc complexes with the quinolone antibacterial drugs enrofloxacin and oxolinic acid in the presence of the nitrogen donor heterocyclic ligand pyridine have been synthesized and characterized. The experimental data suggest that the quinolone ligands are on the deprotonated mode acting as bidentate ligands coordinated to the zinc(II) ion through the ketone oxygen and a carboxylato oxygen. The crystal structure of the complex bis(enrofloxacinato)bis(pyridine)zinc(II), 1, has been determined with X-ray crystallography. The biological activity of the complexes has been evaluated by examining their ability to bind to calf-thymus DNA (CT-DNA) with UV and fluorescence spectroscopies. UV spectroscopic titration studies of the interaction of the complexes with DNA have shown that they can bind to CT-DNA and the DNA binding constants have been calculated. Competitive studies with ethidium bromide (EB) have shown that the complexes exhibit the ability to displace the DNA-bound EB indicating that they can bind to DNA in strong competition with EB for the intercalative binding site. 相似文献
432.
Alexandropoulos DI Mukherjee S Papatriantafyllopoulou C Raptopoulou CP Psycharis V Bekiari V Christou G Stamatatos TC 《Inorganic chemistry》2011,50(22):11276-11278
The initial employment of 2-(hydroxymethyl)pyridine in 4f metal chemistry has afforded a new family of Ln(III)(9) clusters with a sandglass-like topology and dual physical properties; the Dy(III) member shows single-molecule magnetism behavior, while the Eu(III) analogue exhibits intense red photoluminescence. 相似文献
433.
Paleos CM Tsiourvas D Sideratou Z 《Langmuir : the ACS journal of surfaces and colloids》2012,28(5):2337-2346
Various strategies for constructing artificial multicompartment vesicular systems, which primitively mimic the structure of eukaryotic cells, are presented. These model systems are appropriate for addressing several issues such as the understanding of cell processes, the development of nanoreactors and novel multicompartment delivery systems for specific drug applications, the transport through bilayer membranes, and also hypothesizing on the evolution of eukaryotic cells as originating from the symbiotic association of prokaryotes. 相似文献
434.
D Kalaitzakis T Montagnon I Alexopoulou G Vassilikogiannakis 《Angewandte Chemie (International ed. in English)》2012,51(35):8868-8871
All in one: Meyers' bicyclic lactams were synthesized in high yield from furans using a new and powerful method that involves a one-pot singlet-oxygen-initiated reaction cascade (see scheme; TFA=trifluoroacetic acid). This method has broad synthetic potential because of the ease of access to a wide range of furans with a variety of substituents. 相似文献
435.
Alexandropoulos DI Manos MJ Papatriantafyllopoulou C Mukherjee S Tasiopoulos AJ Perlepes SP Christou G Stamatatos TC 《Dalton transactions (Cambridge, England : 2003)》2012,41(16):4744-4747
A Mn(III)(4)Ni(II)(4) molecular square exhibiting slow magnetization relaxation has been prepared from the reaction of a Mn(II)(4)Mn(III)(6)Mn(IV)(2) cluster and a simple Ni(II) source. 相似文献
436.
We give necessary and sufficient criteria for a distribution to be smooth or uniformly Hölder continuous in terms of approximation sequences by smooth functions; in particular, in terms of those arising as regularizations ${(T\ast\phi_{n})}$ . 相似文献
437.
In this paper, we consider adjustable robust versions of convex optimization problems with uncertain constraints and objectives and show that under fairly general assumptions, a static robust solution provides a good approximation for these adjustable robust problems. An adjustable robust optimization problem is usually intractable since it requires to compute a solution for all possible realizations of uncertain parameters, while an optimal static solution can be computed efficiently in most cases if the corresponding deterministic problem is tractable. The performance of the optimal static robust solution is related to a fundamental geometric property, namely, the symmetry of the uncertainty set. Our work allows for the constraint and objective function coefficients to be uncertain and for the constraints and objective functions to be convex, thereby providing significant extensions of the results in Bertsimas and Goyal (Math Oper Res 35:284–305, 2010) and Bertsimas et al. (Math Oper Res 36: 24–54, 2011b) where only linear objective and linear constraints were considered. The models in this paper encompass a wide variety of problems in revenue management, resource allocation under uncertainty, scheduling problems with uncertain processing times, semidefinite optimization among many others. To the best of our knowledge, these are the first approximation bounds for adjustable robust convex optimization problems in such generality. 相似文献
438.
Giannakopoulos E Stathi P Dimos K Gournis D Sanakis Y Deligiannakis Y 《Langmuir : the ACS journal of surfaces and colloids》2006,22(16):6863-6873
Humic acids have stable radicals that are indigenous to their structure. Hydroxybenzoic acid derivatives such as gallic acid (GA) and protocatechuic acid are appropriate models for the radical properties of humic acids. Here we show that the adsorption or intercalation of gallic acid in Laponite clay results in a significant thermodynamic stabilization of gallic acid radicals. Moreover, the formed organoclay shows enhanced stability against acid dissolution. The structural details of the association of gallic acid with Laponite depend on the GA/Laponite loading. At low GA/Laponite ratios (approximately 10(-6) M of gallic acid per gram of clay), gallic acid is adsorbed at the variable charge sites of Laponite. This adsorption can be adequately described by surface complexation modeling. At higher GA/Laponite ratios (approximately 10(-3) M of gallic acid per gram of clay), X-ray diffraction data show that gallic acid is intercalated at the interlamellar sites of Laponite. In the presence of Pb2+ ions, the formed GA/Pb complex is associated with Laponite in an analogous structural manner, that is, adsorption at variable charge sites or intercalation at the interlamellar sites of Laponite, depending on the loading. Laponite stabilizes the GA/Pb radicals. At prolonged exposure to ambient O2, Laponite promotes the formation of stable oligomeric GA/Pb radical species, which are intercalated into interlamellar sites. 相似文献
439.
Birefringent computer-generated holograms are fabricated in bulk fused silica by tight focusing of infrared femtosecond laser pulses. The polarization properties of the elliptically polarized diffracted light are in excellent agreement with the theoretical model. We experimentally demonstrate that for such birefringent structures the signal-to-noise ratio increases by approximately 9 dB when polarization filtering is used to suppress the undiffracted beam. 相似文献
440.
Vasso Triantafyllopoulou Dimitris Mentzafos Frantzeska Tsorteki Kostas Bethanis 《Journal of chemical crystallography》2012,42(3):238-244