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451.
Burel-Deschamps L Mével M Loizeau D Ayadi F Yaouanc JJ Clément JC Jaffrès PA Giamarchi P 《Journal of fluorescence》2008,18(5):835-841
We report here a study on the physicochemical properties of cationic phospholipids liposomes used for lipoplex formulation
and DNA transfer. The original cationic phospholipids synthesized in our laboratory are first presented with the liposome
formulation process. The second part deals with the liposomes fusogenic properties studied by fluorescence resonant energy
transfer (FRET). The nature of the cationic polar head and the formulation with or without a neutral colipid have a great
influence on the FRET signal. The third part reports the study of the viscosity of the liposome by fluorescence anisotropy
measurements. It has been observed that the vectors having a saturated lipid chain exhibit a more pronounced anisotropy than
those having unsaturated lipid chains. Finally, liposomes formed by a mixture of phospholipids and DC-Chol (a rigid lipid)
leads to increase the anisotropy denoting a more rigid liposome. 相似文献
452.
Vega Iel D Gale PA Light ME Loeb SJ 《Chemical communications (Cambridge, England)》2005,(39):4913-4915
Anion complexation studies on a series of platinum(II) tetrakis(pyrrolylpyridine) salts demonstrate the importance of CH-anion hydrogen bonds in coordinating anionic guests in solution and the solid-state. 相似文献
453.
454.
Jean-Jacques Delpuech 《Magnetic resonance in chemistry : MRC》1970,2(2):91-107
Nitrogen in version rate of an amine may be brought to within the NMR time-scale by use of an acidic medium of variable pH, in which it is almost completely prevented through protonation. Rigorous equations are derived for computing this rate from the mean lifetime of the ammonium cation determined by NMR spectroscopy. The validity of Saunders and Yamada's approximate formula is discussed: the protonation rate of the amine must be far larger than its nitrogen inversion rate, while the rate at which the salt loses its acidic proton is immaterial. If in version occurs between two different isomers, the equilibrium ratio of the isomeric cations is also derived. 相似文献
455.
456.
P. Jean-Jacques?HeringsEmail author Ana?Mauleon Vincent J.?Vannetelbosch 《International Journal of Game Theory》2004,32(4):519-531
We revisit n-player coordination games with Pareto-ranked Nash equilibria. As a novelty, we introduce fuzzy play and a matching device. By fuzzy play we mean that each player does not choose which pure strategy to play, but instead chooses a nonempty subset of his strategy set that he submits to the matching device. The matching device is a very simple one. It randomly selects a match if possible, and it selects randomly some strategy belonging to the strategy set sent by each player otherwise. That is, it does not impose that the best alternatives are matched. Using the concepts of perfect Nash equilibrium and of trembling-hand perfect rationalizability, we show that players coordinate directly on the Pareto optimal outcome. This implies that they neither use the option of fuzzy play, nor make use of the matching device.We thank an anonymous referee and an Associate Editor for valuable comments. Jean-Jacques Herings would like to thank the Netherlands Organisation for Scientific Research (NWO) for financial support. Vincent Vannetelbosch is Chercheur Qualifié at the Fonds National de la Recherche Scientifique. The research of Ana Mauleon has been made possible by a fellowship of the Fonds Européen du Développement Economique Régional (FEDER). Financial support from the Belgian French Communitys program Action de Recherches Concertée 99/04-235 (IRES, Université catholique de Louvain) is gratefully acknowledged. 相似文献
457.
Sound velocity is a main parameter in non destructive characterization, closely related to the elastic properties and to the microstructure of heterogeneous materials.The accurate determination of the sound velocity using pulse-echo technique relies on the ability to reduce pulse distortion and to measure specimen dimensions with a high precision. In the field of bio-mimetic materials and biological tissues, the nature of the specimen makes this last requirement highly difficult or inappropriate.The present work, using a through-transmission configuration, allows, in a stress free environment, to access the sound velocity in soft, low acoustic contrast materials without requiring the specimen dimensions. The specimen sound velocity is obtained from the echo time-of-flights through a Z-scan process providing the absolute medium sound velocity as reference.The technique uses an excitation burst at a frequency below the transducer resonance to ensure a significantly reduction in pulse distortions and improve signal-to-noise ratio. The accurate determination of the echo time-of-flight relies on a highly efficient cross-correlation/Hilbert transform signal processing.The method has been applied to gel-based emulsions of different microstructures considered as biomimetic phantoms, as well as to their constituents: pure gelatin and vegetable oil. 相似文献
458.
459.
Jean-Jacques Brunet Remi Chauvin Ousmane Diallo Bruno Donnadieu Joëlle Jaffart Denis Neibecker 《Journal of organometallic chemistry》1998,570(2):9166
KHFe(CO)4 reacts with tris(amino)phosphines by substitution at phosphorus leading to [bis(amino)phosphine]tetracarbonyliron complexes [(R1R2N)2PH]Fe(CO)4. The X-ray structure has been determined for R1=R2=Ph. Deprotonation of these complexes with KH affords stable potassium phosphidotetracarbonylferrates which can be alkylated or acylated at phosphorus. 相似文献
460.