Blowup of solutions to generalized Keller–Segel model

The existence and nonexistence of global in time solutions is studied for a class of equations generalizing the chemotaxis model of Keller and Segel. These equations involve Lévy diffusion operators and general potential type nonlinear terms.     

Uniqueness of minimal Fourier-type extensions in L_1-spaces

We give a characterization of uniqueness of finite rank Fourier-type minimal extensions in $L_1$ -norm. This generalizes the main result obtained by Lewicki (Proceedings of the Fifth International Conference on Function Spaces, Lecture Notes in Pure and Applied Mathematics, vol. 213, pp. 337–345, 1998) to the case of $n$ -circular sets in $\mathbb{C }^n$ .     

Statistical approach to multiple-q modulated structures: average Patterson analysis

Using a statistical approach, the average unit cells have been constructed for modulated structures with different types of modulation, from simple sinusoidal to square-wave functions. The obtained unit cells fully describe diffraction intensities of the main reflections and their satellites. A universal distribution, valid for different lengths of the modulation vector, has been found. Average Patterson functions have been constructed and used to distinguish between different types of modulation.     

Helical twisting power of antiferroelectric chiral terphenyls in different matrices

To determine the influence of chemical structure on the Helical Twisting Power (HTP), we tested four optically active dopants having a terphenyl rigid core and the same chiral centre but differing in the length of nonchiral terminal chain and the substitution of benzene rings with fluorine atoms. The compounds were added to different achiral liquid crystalline matrices: nematic and smectic C. It was found that HTP as well as its temperature variation depends on the kind of used matrices. It gives a conclusion that information about HTP obtained in one matrix cannot be uncritically transferred to another one.     

The Properties of Cu Ions in Zeolites CuY Studied by IR Spectroscopy

The properties of both Cu²⁺ and Cu⁺ ions in zeolite CuY were followed with NO and CO as probe molecules. Cu²⁺ was found to be located in S_II, S_II*, and S_III sites, whereas Cu⁺ was found in S_II and S_II* sites. The fine analysis of the spectra of Cu²⁺-NO and Cu⁺-CO adducts suggests that both in S_II and in S_II* sites two kinds of Cu cations exist. They differ in the positive charge, which may be related to the varying numbers of AlO₄⁻ in close proximity. The experiments of NO and CO adsorption and desorption evidenced that both Cu²⁺ and Cu⁺ sites of highest positive charge bind probe molecules most strongly but activate them to a lesser extent than the Cu sites of lowest positive charge. The experiments of reduction with hydrogen evidenced that the Cu ions of higher positive charge are first reduced by hydrogen. On the other hand, Cu sites of the lowest positive charge are first oxidized by oxygen. The experiments with CuNaY zeolites of various Cu contents suggest that the first introduced Cu (at low Cu contents) created Cu⁺, which was the most neutralized by framework oxygens. Such Cu cations are the most stabilized by framework oxygens.     

Multi-component PZT ceramics obtained by mechanochemical activation and conventional ceramic technology

Journal of Thermal Analysis and Calorimetry - Numerical predictions of flow boiling in a square tube rotating in vertical direction at a uniform rotating speed are presented. There-dimensional...     

The Impacts of Crystalline Structure and Different Surface Functional Groups on Drug Release and the Osseointegration Process of Nanostructured TiO2

In implantable materials, surface topography and chemistry are the most important in the effective osseointegration and interaction with drug molecules. Therefore, structural and surface modifications of nanostructured titanium dioxide (TiO₂) layers are reported in the present work. In particular, the modification of annealed TiO₂ samples with —OH groups and silane derivatives, confirmed by X-ray photoelectron spectroscopy, is shown. Moreover, the ibuprofen release process was studied regarding the desorption-desorption-diffusion (DDD) kinetic model. The results proved that the most significant impact on the release profile is annealing, and further surface modifications did not change its kinetics. Additionally, the cell adhesion and proliferation were examined based on the MTS test and immunofluorescent staining. The obtained data showed that the proposed changes in the surface chemistry enhance the samples’ hydrophilicity. Moreover, improvements in the adhesion and proliferation of the MG-63 cells were observed.