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排序方式: 共有182条查询结果,搜索用时 62 毫秒
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Bonincontro A Spigone E Ruiz Peña M Letizia C La Mesa C 《Journal of colloid and interface science》2006,304(2):342-347
Mixing aqueous sodium dodecylsulfate with cetyltrimethylammonium bromide solutions in mole ratios close to (1.7/1.0) allows the formation of cat-anionic vesicles with an excess of negative charges on the outer surface. The vesicular dispersions are mixed with lysozyme, and interact electrostatically with the positive charges on the protein, forming lipo-plexes. Dielectric relaxation, zeta-potential, and light scattering indicate the occurrence of interactions between vesicles and the protein. According to CD, the vesicle-adsorbed protein retains its native conformation. Binding and surface saturation, inferred by dielectric relaxation and zeta-potential, fulfil a charge neutralisation stoichiometry. Adsorbed lysozyme promotes the vesicle clustering and is concomitant with the lipo-plexes flocculation. Above the charge neutralisation threshold, lysozyme in excess remains dispersed in molecular form. Attempts were made to determine in what conditions protein release from the vesicles occurs. Accordingly, the full neutralisation of sodium dodecylsulfate in excess by cetyltrimethylammonium bromide ensures the lipo-plexes break-up, the precipitation of the mixed surfactants and the protein release in native form. 相似文献
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44.
Maria Letizia Bertotti 《Journal of Differential Equations》2010,249(11):2757-2770
In this paper we discuss and analyze a two-parameter family of systems of quadratic ordinary differential equations of interest in applied sciences, whose dynamics exhibits an emerging cluster structure. 相似文献
45.
Barreca ML Gitto R Quartarone S De Luca L De Sarro G Chimirri A 《Journal of chemical information and computer sciences》2003,43(2):651-655
A three-dimensional pharmacophore model for the binding of noncompetitive AMPA receptor antagonists was developed in order to map common structural features of highly active compounds. This hypothesis, which consists of two hydrophobic regions, one hydrogen bond acceptor and one aromatic region, was successfully used as framework for the design of a new class of allosteric modulators containing a tetrahydroisoquinoline skeleton and for in silico screening. The promising biological results suggested that the identified molecules might be useful "lead compounds" for future drug development. 相似文献
46.
Maria Letizia Ciavatta Margherita Gavagnin Raffaella Puliti Lelio Mazzarella Jamie S. Simpson 《Tetrahedron》2005,61(33):8049-8053
The absolute stereochemistry of amphilectene metabolites from Cribochalina sp. has been revised by a detailed NMR spectroscopic study of the Mosher ester derivatives of a related alcohol. The relative stereochemistry of the previously described amphilectenes has been reinvestigated and reassigned on the basis of the X-ray structural analysis carried out on one of them. The structure of a new amphilectene metabolite, which is an isothiocyanato analogue is also presented. 相似文献
47.
Bartoli G Bosco M Giuliani A Marcantoni E Palmieri A Petrini M Sambri L 《The Journal of organic chemistry》2004,69(4):1290-1297
The Lewis acid promoted allylation of aldehydes has become an important carbon-carbon bond forming reaction in organic chemistry. In this context, we have developed an alternative over existing catalytic processes, wherein aldehydes are subject in acetonitrile to reaction of allylation with allyltributylstannane in the presence of 1.0 equiv of cerium(III) chloride heptahydrate (CeCl(3).7H(2)O), an inexpensive and mild Lewis acid. The allylation has been accelerated by using an inorganic iodide as a cocatalyst, and various iodide salts were examined. The procedure must use allylstannane reagent instead of allylsilane reagent, desirable for environmental reasons, but high chemoselectivity was observed, and this is opposite the results obtained with other classical Lewis acids such as TiCl(4) and Et(2)O.BF(3). 相似文献
48.
Emiliano Manzo M. Letizia Ciavatta Raffaella Puliti Yue-Wei Guo Guido Cimino 《Tetrahedron》2005,61(31):7456-7460
Three novel halogenated C15-acetogenins, compounds 1-3, have been isolated, together with known metabolites, from a South China Sea collection of the anaspidean mollusc Aplysia dactylomela. The structures have been suggested by both NMR analysis and comparison with literature data. The structure of 1 was confirmed by a single crystal X-ray study, which also allowed the establishment of its absolute stereochemistry. 相似文献
49.
Emiliano Manzo Maria Letizia Ciavatta Ernesto Mollo Guido Cimino 《Tetrahedron letters》2005,46(3):465-468
A new γ-pyrone propionate, compound 9, and its peroxy derivative 10 have been isolated from the sacoglossan Placobranchus ocellatus. The structure and the relative stereochemistry of the new molecules, which displayed an unprecedented carbon skeleton characterised by a bicyclo [4.2.0] octane, have been determined by both spectroscopic methods and comparison with model compounds. By analogy with photodeoxytridachione (2), a sunscreen protective role could be also suggested for compound 9 in living P. ocellatus. 相似文献
50.
Letizia Pellegrini Shengkun Zhu 《Journal of Optimization Theory and Applications》2018,177(3):788-810
The scalar finite-dimensional case has been discussed in the first part of this work series, which aims at exploiting the image space analysis to establish a general regularity condition for constrained extremum problems. Based on this preliminary result, the present paper dedicates itself to further study the regularity conditions for vector constrained extremum problems in a Euclidean space. The case of infinite-dimensional image will be the subject of a subsequent paper. 相似文献