Aligned nanofibres made of poly(3-hydroxybutyrate) grafted to hyaluronan for potential healthcare applications

In this work, a hybrid copolymer consisting of poly(3-hydroxybutyrate) grafted to hyaluronic acid (HA) was synthesised and characterised. Once formed, the P(3HB)-g-HA copolymer was soluble in water allowing a green electrospinning process. The diameters of nanofibres can be tailored by simply varying the Mw of polymer. The optimization of the process allowed to produce fibres of average diameter in the range of 100-150 nm and low polydispersity. The hydrophobic modification has not only increased the fibre diameter, but also the obtained layers were homogenous. At the nanoscale, the hybrid copolymer exhibited an unusual hairy topography. Moreover, the hardness and tensile properties of the hybrid were found to be superior compared to fibres made of unmodified HA. Particularly, this reinforcement was achieved at the longitudinal direction. Additionally, this work reports the use in the composition of a water-soluble copolymer containing photo cross-linkable moieties to produce insoluble materials post-electrospinning. The derivatives as well as their nanofibrous mats retain the biocompatibility of the natural polymers used for the fabrication

Director´s actor - actor´s director

I deal with the relationship of the actor and director in my diploma work. First I try to describe some types of directors according to their work with actors and rehearsing with them during staging. I endeavour after a short view of theory of this problem. Then I try to describe two different types of directors: director ? stage manager and actors´ director; as a special case of actors´ director I present director ? actor. In the second part of my diploma work I present concrete examples types mentioned above; it is based on my personal experience taken from my praxis up to now. I deal with Thomas Zielinski and his staging of Streetcar named Desire as an example of director ? stage manager, Ján Šimko in rehearsing Bedbound as an example of actors´ director and Ondřej Pavelka as a director- actor in rehearsing Faust. I try to review my acknowledgments from theory and praxis in the end of my work

Synthesis and Physicochemical Characterization of Undecylenic Acid Grafted to Hyaluronan for Encapsulation of Antioxidants and Chemical Crosslinking

In this work, a new amphiphilic derivative made of 10-undecylenic acid grafted to hyaluronan was prepared by mixed anhydrides. The reaction conditions were optimized, and the effect of the molecular weight (Mw), reaction time, and the molar ratio of reagents was explored. Using this methodology, a degree of substitution up to 50% can be obtained. The viscosity of the conjugate can be controlled by varying the substitution degree. The physicochemical characterization of the modified hyaluronan was performed by infrared spectroscopy, Nuclear Magnetic Resonance, Size-Exclusion Chromatography combined with Multiangle Laser Light Scattering (SEC-MALLS), and rheology. The low proton motility and self-aggregation of the amphiphilic conjugate produced overestimation of the degree of substitution. Thus, a novel method using proton NMR was developed. Encapsulation of model hydrophobic guest molecules, coenzyme Q10, curcumin, and α-tocopherol into the micellar core was also investigated by solvent evaporation. HA-UDA amphiphiles were also shown to self-assemble into spherical nanostructures (about 300 nm) in water as established by dynamic light scattering. Furthermore, HA-UDA was crosslinked via radical polymerization mediated by ammonium persulphate (APS/TEMED). The cross-linking was also tested by photo-polymerization catalyzed by Irgacure 2959. The presence of the hydrophobic moiety decreases the swelling degree of the prepared hydrogels compared to methacrylated-HA. Here, we report a novel hybrid hyaluronan (HA) hydrogel system of physically encapsulated active compounds and chemical crosslinking for potential applications in drug delivery

Profiling of adrenal corticosteroids in blood and local tissues of mice during chronic stress

Abstract Stress increases plasma concentrations of corticosteroids, however, their tissue levels are unclear. Using a repeated social defeat paradigm, we examined the impact of chronic stress on tissue levels of corticosterone (CORT), progesterone (PROG), 11-deoxycorticosterone (11DOC) and 11-dehydrocorticosterone (11DHC) and on gut microbiota, which may reshape the stress response. Male BALB/c mice, liquid chromatography-tandem mass spectrometry and 16S RNA gene sequencing were used to screen steroid levels and fecal microbiome, respectively. Stress induced greater increase of CORT in the brain, liver, and kidney than in the colon and lymphoid organs, whereas 11DHC was the highest in the colon, liver and kidney and much lower in the brain and lymphoid organs. The CORT/11DHC ratio in plasma was similar to the brain but much lower in other organs. Stress also altered tissue levels of PROG and 11DOC and the PROG/11DOC ratio was much higher in lymphoid organs that in plasma and other organs. Stress impacted the β- but not the α-diversity of the gut microbiota and LEfSe analysis revealed several biomarkers associated with stress treatment. Our data indicate that social defeat stress modulates gut microbiota diversity and induces tissue-dependent changes in local levels of corticosteroids, which often do not reflect their systemic levels