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951.
LetE be a complex Banach space with open unit ballB
e. The structure of the space of composition operators on the Banach algebra H∞, of bounded analytic functions onB
e with the uniform topology, is studied. We prove that the composition operators arising from mappings whose range lies strictly
insideB
e form a path connected component. WhenE is a Hilbert space or aC
o(X)- space, the path connected components are shown to be the open balls of radius 2.
The research of this author was supported by grant number SAB1999-0214 from the Ministerio de Educación, Cultura y Deporte
during his stay at the Universidad de Valencia.
The research of this author was partially supported DGES(Spain) pr. 96-0758.
The research of this author was partially supported by Magnus Ehrnrooths stiftelse. 相似文献
952.
953.
S. Pellice Pablo Galliano Y. Castro A. Durán 《Journal of Sol-Gel Science and Technology》2003,28(1):81-86
Hybrids sols from tetraetoxysilane (TEOS) and 3-(methacryloxypropyl) trimethoxysilane (-MPS) were prepared in acid medium for different TEOS/-MPS ratios and were modified by the addition of a colloidal silica suspension. The stability of the different sols was evaluated by viscosity measurements; the sols showed a Newtonian behaviour and the ageing effect was negligible even after two months from their preparation. Coatings were obtained by dipping at different withdrawal rates and heat-treated between 150 and 250°C. Transparent coatings with thickness higher than 4 m were reached for most of the studied compositions. The surface microhardness of coatings for each composition and thermal treatment was evaluated by the pencil hardness test. The thermal stability was followed by simultaneous thermogravimetric and differential thermal analysis (TGA-DTA) determining the limit temperatures at which the coatings can be treated without losingits hybrid character. A structural analysis was made by deconvolution of Fourier transformed infrared spectra (FTIR) of self-supported films observing the influence of the organic groups on the silica network. 相似文献
954.
Vanine Mazzieri Fernando Coloma-Pascual Mónica González Pablo L"argentire Nora Fígoli 《Reaction Kinetics and Catalysis Letters》2002,76(1):53-59
Increasing reduction time increases ruthenium reduction, but even after 6 h, ruthenium is not completely reduced and chlorine is not completely eliminated in Ru/Al2O3 prepared from RuCl3. 相似文献
955.
The addition of dianions of carboxylic acids to bromoacetonitrile, leads, in good yields, to the corresponding γ-cyanoacids that give γ-aminoacids on hydrogenation. This two-step methodology improves the results previously described. 相似文献
956.
Dulce?Paloma?del J.?Gutiérrez-Hijar Fausto?Becerra Jorge?E.?Puig J.?Félix?Armando?Soltero-Martínez María?Belén?Sierra Pablo?C.?SchulzEmail author 《Colloid and polymer science》2004,283(1):84-90
The partial molar volume and hydration number of two micellised polymerisable surfactants (dodecylethylmethacrylatedimethylammonium bromide (C12PS) and hexadecylethylmethacrylatedimethylammonium bromide (C16PS)) were determined. Results support marginally the annular conformation of the polar head group (N+(CH3)2-CH2-CH2-O-CO-C(CH3)(=CH2)) proposed in the literature. 相似文献
957.
Marcela?A.?Morini Paula?V.?Messina Pablo?C.?SchulzEmail author 《Colloid and polymer science》2005,283(11):1206-1218
The effect of NaCl and HCl on two non-ionic surfactant micelles was studied using several techniques, including conductivity
and ion-selective electrodes. Both surfactants exhibit opposite behaviour. When Tween 20 is titrated with HCl the conductivity
notably increases in comparison with water, whereas that of Triton X-100 solutions do not change with respect to water until
a certain HCl concentration is reached, when it increases. The hydrogen ion activity is lower in Triton X-100 solutions and
higher in Tween 20 solutions than in pure water. Chloride ion activity is higher in Tween 20 solutions than in water, whereas
in Triton X-100 the activity does not significantly differ from that in water. The activity of sodium ion is lower in Tween
20 solutions than in water, whereas that in Triton X-100 solutions does not differ from the titration of water. These phenomena
are explained by the changes in conformation of the non-ionic headgroups, which capture water, and in some cases ions, modifying
the activity of ions in the intermicellar solution. 相似文献
958.
959.
Miriam de J. Velsquez-Hernndez Efwita Astria Sarah Winkler Weibin Liang Helmar Wiltsche Arpita Poddar Ravi Shukla Glenn Prestwich John Paderi Pablo Salcedo-Abraira Heinz Amenitsch Patricia Horcajada Christian J. Doonan Paolo Falcaro 《Chemical science》2020,11(39):10835
Glycosaminoglycans (GAGs) are biomacromolecules necessary for the regulation of different biological functions. In medicine, GAGs are important commercial therapeutics widely used for the treatment of thrombosis, inflammation, osteoarthritis and wound healing. However, protocols for the encapsulation of GAGs in MOFs carriers are not yet available. Here, we successfully encapsulated GAG-based clinical drugs (heparin, hyaluronic acid, chondroitin sulfate, dermatan sulfate) and two new biotherapeutics in preclinical stage (GM-1111 and HepSYL proteoglycan) in three different pH-responsive metal-azolate frameworks (ZIF-8, ZIF-90, and MAF-7). The resultant GAG@MOF biocomposites present significant differences in terms of crystallinity, particle size, and spatial distribution of the cargo, which influences the drug-release kinetics upon applying an acidic stimulus. For a selected system, heparin@MOF, the released therapeutic retained its antithrombotic activity while the MOF shell effectively protects the drug from heparin lyase. By using different MOF shells, the present approach enables the preparation of GAG-based biocomposites with tunable properties such as encapsulation efficiency, protection and release.Clinical and pre-clinical GAG-based biotherapeutics were encapsulated within three metal-azolate frameworks (ZIF-8, ZIF-90, and MAF-7). The resulting MOF biocomposites show different loading capacity, biopreservation properties and release profiles. 相似文献
960.
Taboada P Velasquez G Barbosa S Castelletto V Nixon SK Yang Z Heatley F Hamley IW Ashford M Mosquera V Attwood D Booth C 《Langmuir : the ACS journal of surfaces and colloids》2005,21(12):5263-5271
Three triblock copolymers of ethylene oxide and phenyl glycidyl ether, type E(m)G(n)E(m), where G = OCH2CH(CH2OC6H5) and E = OCH2CH2, were synthesized and characterized by gel-permeation chromatography, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and NMR spectroscopy. Their association properties in aqueous solution were investigated by surface tensiometry and light scattering, yielding values of the critical micelle concentration (cmc), the hydrodynamic radius, and the association number. Gel boundaries in concentrated micellar solution were investigated by tube inversion, and for one copolymer, the temperature and frequency dependence of the dynamic moduli served to confirm and extend the phase diagram and to highlight gel properties. Small-angle X-ray scattering was used to investigate gel structure. The overall aim of the work was to define a block copolymer micellar system with better solubilization capacity for poorly soluble aromatic drugs than had been achieved so far by use of block copoly(oxyalkylene)s. Judged by the solubilization of griseofulvin in aqueous solutions of the E(m)G(n)E(m) copolymers, this aim was achieved. 相似文献