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排序方式: 共有176条查询结果,搜索用时 15 毫秒
31.
JV Georgieva RP Brinkhuis K Stojanov CA Weijers H Zuilhof FP Rutjes D Hoekstra JC van Hest IS Zuhorn 《Angewandte Chemie (International ed. in English)》2012,51(33):8339-8342
A polymeric nanocarrier: Polymersomes tagged with a dodecamer peptide that recognizes gangliosides GM1 and GT1b are shown to cross the blood-brain barrier, both in an in?vitro model and in?vivo. The combination of polymeric vesicles with a small GM1-binding peptide and GM1/GT1b gangliosides as targeting sites for blood-brain barrier transport is unprecedented. 相似文献
32.
33.
Studying the kinetics of isothermal decomposition
of thirteen selenites at isothermal heating, the values of activation energy E of the process, pre-exponential factor A in Arrhenius equation and changes of entropy for
the formation of the activated complex of the reagent were calculated. Direct
dependence between the thermal stability of the selenites and their cation
radii on their 'hardness' or 'softness' was found.
The dependence was interpreted in the terms of the generalized perturbation
theory of chemical reactivity. Kinetic compensation effect was observed only
for the selenites, which thermally decompose by the same mechanism. 相似文献
34.
Donath E Moya S Neu B Sukhorukov GB Georgieva R Voigt A Bäumler H Kiesewetter H Möhwald H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(23):5481-5485
Three-dimensional ultrathin polymer shells have been produced by a combination of step-by-step adsorption of polyelectrolytes on glutaraldehyde-treated human erythrocytes and subsequent solubilization of the cytoplasmatic constituents by means of a deproteinizing agent. The obtained hollow films preserve both the size and shape of the templating cells. This opens a pathway for the fabrication of polymeric capsules within a wide range of size and shape by using various biological templates. They may have exciting potential applications, such as templates for nanocomposites, as containers for a large class of materials, or as cages for chemical reactions. The thickness of the films can be adjusted over a large range: from a few nm up to several tens of nm. The polymer shells are permeable to small molecules and ions but not to macromolecules. An increase in the ionic strength of the solution up to 100 mmol make the capsules permeable for proteins. Permeability and conductivity studies have provided evidence that the adsorption of lipids on polyelectrolyte layers is a means of producing capsules with controlled permeability properties. 6-Carboxyfluorescein and Rhodamin 6G were precipitated within the capsules. 相似文献
35.
St. Christoskova M. Stoyanova M. Georgieva 《Reaction Kinetics and Catalysis Letters》2000,70(1):139-145
Catalytic oxidation of sulfide ions in aqueous solutions by air oxygen has been investigated using a Ni-oxide system as a catalyst. The kinetics and the selectivity of the oxidation process were studied by varying the pH, catalyst amount and reaction temperature. A reduction/oxidation mechanism of the reaction has been supposed comprising interaction between the surface active oxygen of the catalyst and HS– and reoxidizing of the reduced catalyst by the dissolved oxygen. The results obtained show that the Ni-oxide system is a promising catalyst for practical application. 相似文献
36.
The nanocrystal thin films of zinc oxide doped by Al (ZnO:Al) were deposited by dc reactive magnetron sputtering on the glass substrates, in the pressure range of 33-51 Pa. From the X-ray diffraction patterns, the nanocrystalline structure of ZnO:Al films and the grain size were determined. The optical transmission spectra depend from the sputtering pressure, but their average value was 90% in the range from 33 Pa to 47 Pa. Also, the sputtering pressure changes the optical band gap of ZnO:Al films, which is highest for films deposited at 37 Pa, 40 Pa and 47 Pa. The obtained films at room temperature have a sheet resistance of 190 Ω/cm2 which increases with time, but the films annealed at temperature of 400 °C have constant resistance. The surface morphology of the films was studied by Scanning electron microscopy. XPS spectra showed that the peak of O1s of the as-deposited films is smaller than the peak of the annealed ZnO:Al films. 相似文献
37.
I. Dimov R. Georgieva Tz. Ostromsky 《Journal of Computational and Applied Mathematics》2010,235(2):391-402
A systematic procedure for sensitivity analysis of a case study in the area of air pollution modeling has been performed. Contemporary mathematical models should include a large set of chemical and photochemical reactions to be established as a reliable simulation tool. The Unified Danish Eulerian Model is in the focus of our investigation as one of the most advanced large-scale mathematical models that describes adequately all physical and chemical processes.Variance-based methods are one of the most often used approaches for providing sensitivity analysis. To measure the extent of influence of the variation of the chemical rate constants in the mathematical model over pollutants’ concentrations the Sobol’ global sensitivity indices are estimated using efficient techniques for small sensitivity indices to avoid a loss of accuracy. Studying relationships between input parameters and the model’s output as well as internal mechanisms is very useful for a verification and an improvement of the model and also for development of monitoring and control strategies of harmful emissions, for a reliable prediction of the final output of scenarios when the concentration levels of pollutants are exceeded. The proposed procedure can also be applied when other large-scale mathematical models are used. 相似文献
38.
St. Christoskova M. Stojanova M. Georgieva 《Reaction Kinetics and Catalysis Letters》1999,67(1):59-66
The low-temperature oxidation of cyanide ions to CO2 and N2 in an aqueous phase in the presence of Ni-oxide system has been studied. The effect of pH, temperature and catalyst amount
on the rate and selectivity of the oxidation process have been investigated. A kinetic model of the reaction studied is proposed
based on the experimental results. It can be used to develop a catalytic method for purification of CN containing wastewaters. 相似文献
39.
Expressions for q-similarity transformations with respect to the symmetric q-exponentials are investigated. It is found that a series in multiple q-commutators can be formulated. The values of the qs in the different q-commutators are obtained by solving systems of algebraic equations. 相似文献
40.
Infrared and Raman spectra of 1,1-(methylphosphinylidene) bis(methanamine) [mpbm, (CH3)PO(CH2NH2)2] and its N,N′-coordinated Pt(II) and Pd(II) have been studied in the 4000–200 cm−1 frequency range. Ab initio calculations have been carried out for different conformations of the mpbm at HF/6-31G* level of the theory from which structural parameters, conformational stability and predicted infrared and Raman spectra have been obtained. A complete vibrational assignment of the lowest energy conformer, tttg−, as well as of its N,N′-coordinated Pt(II) and Pd(II) chloro-complexes was done on the basis of the calculated frequencies, relative infrared intensities, Raman activities and potential energy distribution (PED). The theoretical predictions are compared with the experimental results where appropriate. 相似文献