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Brno, Czech Republic

Vyslouzil J.,University of Veterinary And Pharmaceutical Sciences Brno | Dolezel P.,University of Veterinary And Pharmaceutical Sciences Brno | Kejdusova M.,University of Veterinary And Pharmaceutical Sciences Brno | Maskova E.,University of Veterinary And Pharmaceutical Sciences Brno | And 5 more authors.
Acta Pharmaceutica | Year: 2014

The main objective of this study was to evaluate the influence of the formulation and process parameters on PLGA microparticles containing a practically insoluble model drug (ibuprofen) prepared by the o/w solvent evaporation method. Multivariate data analysis was used. The effects of altered stirring speed of a mechanical stirrer (600, 1000 rpm), emulsifier concentrations (PVA concentration 0.1 %, 1 %) and solvent selection (dichloromethane, ethyl acetate) on microparticle characteristics (encapsulation efficiency, drug loading, burst effect) were observed. It was found that with increased stirring speed, the PVA concentration or the use of ethyl acetate had a significantly negative effect on encapsulation efficiency. In addition, ethyl acetate had an adverse effect on the burst effect, while increased stirring speed had the opposite effect. Drug load was not affected by any particular variable, but rather by the interactions of evaluated variables. © 2014 by Kateřina Dvořáčková.

Satori C.P.,University of Minnesota | Henderson M.M.,University of Minnesota | Krautkramer E.A.,University of Minnesota | Kostal V.,Tescan | And 3 more authors.
Chemical Reviews | Year: 2013

The role that organelle analysis has played in understanding biology is studied. Organelle analysis enables a more specific description of the molecular, biochemical, and physiological processes associated with diseases, embryonic development, tissue differentiation, organism aging, disease treatments, and organism response to pathogens. Confocal microscopy has become a routine tool for investigating subcellular organization, organelle networks, and organelle dynamics in cellular and tissue samples. Most organelles have a dynamic, three-dimensional (3D) organization inside the cell, which is tightly connected to their physiological functions. Due to this, a single 2D image inherently limits the information acquired about the distribution of a particular property within the organelle. The combination of subcellular fractionation with 'omic' technologies has become a powerful resource to characterize and catalogue the various subcellular environments in a cell.

Racek J.,Academy of Sciences of the Czech Republic | Sittner P.,Academy of Sciences of the Czech Republic | Heller L.,Academy of Sciences of the Czech Republic | Pilch J.,Academy of Sciences of the Czech Republic | And 2 more authors.
Journal of Materials Engineering and Performance | Year: 2014

Corrosion behavior of superelastic NiTi shape memory alloy wires with cracked TiO2 surface oxide layers was investigated by electrochemical corrosion tests (Electrochemical Impedance Spectroscopy, Open Circuit Potential, and Potentiodynamic Polarization) on wires bent into U-shapes of various bending radii. Cracks within the oxide on the surface of the bent wires were observed by FIB-SEM and TEM methods. The density and width of the surface oxide cracks dramatically increase with decreasing bending radius. The results of electrochemical experiments consistently show that corrosion properties of NiTi wires with cracked oxide layers (static load keeps the cracks opened) are inferior compared to the corrosion properties of the straight NiTi wires covered by virgin uncracked oxides. Out of the three methods employed, the Electrochemical Impedance Spectroscopy seems to be the most appropriate test for the electrochemical characterization of the cracked oxide layers, since the impedance curves (Nyquist plot) of differently bent NiTi wires can be associated with increasing state of the surface cracking and since the NiTi wires are exposed to similar conditions as the surfaces of NiTi implants in human body. On the other hand, the potentiodynamic polarization test accelerates the corrosion processes and provides clear evidence that the corrosion resistance of bent superelastic NiTi wires degrades with oxide cracking. © 2014 ASM International.

Polonskyi O.,Charles University | Solar P.,Charles University | Kylian O.,Charles University | Drabik M.,Charles University | And 8 more authors.
Thin Solid Films | Year: 2012

Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture. © 2011 Elsevier B.V. All rights reserved.

Kral P.,Academy of Sciences of the Czech Republic | Dluhos J.,Tescan | Perina P.,Tescan | Bartak T.,Tescan
Materials Science Forum | Year: 2013

Experiments were conducted to determine microstructure changes occurring during thermal exposure in metals processed by equal-channel angular pressing (ECAP). The ECAP pressing was performed at room temperature by route Bc. Static annealing and constant load creep tests in tension were conducted at 0.3-0.5 Tm. The microstructure was examined by scanning electron microscope combined with focus ion beam - TESCAN LYRA 3 equipped with electron back scatter diffraction (EBSD). © (2013) Trans Tech Publications, Switzerland.

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