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Self-assembly of polymers with amphiphilic compounds (surfactants) in aqueous solutions
Delisavva, Foteini ; Procházka, Karel (advisor) ; Štěpánek, Petr (referee) ; Pánek, Jiří (referee)
Title: Self-assembly of polymers with amphiphilic compounds (surfactants) in aqueous solutions Abstract: This PhD Thesis is devoted to the co-assembly in systems containing electrically charged polymers (polyelectrolytes and block copolymers containing polyelectrolyte sequences). I studied the interactions between block copolymers and oppositely charged surfactants in aqueous solutions, and the structure and properties of co-assembled nanoparticles by a combination of several experimental methods. I found that the spontaneous formation, solubility and stability of complex nanoparticles depend not only on the electrostatic attractive forces but also on the hydrophobic effects. In a major part of my Thesis, I studied the interaction of polyelectrolytes with oppositely charged gemini surfactants (containing two charged head-groups interconnected by a short linker and two hydrophobic tails) which is a relatively new topic - much less studied than the co-assembly with conventional single tail surfactants. Better understanding of the formation and properties of complexes containing gemini surfactants and polymers provides knowledge that should lead to novel tailor-made nanoparticles with desired properties for applications in medicine and new technologies (including nano-technologies). We have shown that the...
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Aerosol light scattering measurements
Novotná, Nikola ; Zíková, Naděžda (advisor) ; Klán, Miroslav (referee)
This master thesis analyses light scattering on atmospheric aerosols, which has been measured at Košetice observatory in Pelhřimov region since 2012. In the thesis, data are processed for period from 1. 1. 2014 to 31. 12. 2015 which provide representative values of scattering and backscattering light measurement. Angstroem exponent was calculated based on which data corrections were performed. Data were processed using hour steps and compared with meteorological and emissions concentrations data. Correlations were calculated and regressions models estimated in order to verify correctness of measurement and to explore impact of meteorological conditions and emissions concentrations PM2,5 and PM10 on scattering coefficients. Performed analyses imply, that light scattering is higher for higher concentrations of PM2,5 and PM10 and for higher relative air humidity and lower for higher outdoor temperature, total precipitations, and wind speed. In addition, it was showed that light scattering is influenced by wind direction, which determines compositions of aerosols in the sample. Key words: atmospheric aerosol, light scattering, time series evaluation
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Dust trap for light scattering study
Bartoň, Petr ; Pavlů, Jiří (advisor) ; Jeřáb, Martin (referee)
Title: Dust trap for light scattering study Author: Petr Bartoň Department: Department of Surface and Plasma Science Supervisor: doc. RNDr. Jiří Pavlů, Ph.D., Department of Surface and Plasma Science Abstract: Light scattering on small grains is common interaction occurring wi- dely in space environments, including Moon surface, dusty nebulas or even the upper atmosphere of the Earth. For experimental measurements of light scatte- ring intensity profiles, we designed and constructed a unique experiment. Using so called acoustic trapping, we are able to capture a single dust grain (or small water droplet) in midair, to irradiate it with the laser beam, and to observe scattered light directly with the photodiode mounted on a precise goniometer. In the thesis, we present not only construction details, but also the first results, which help us to evaluate abilities of the experiment, and provide useful recommendations for further development of all dust-related experiments. Keywords: light scattering, acoustic trap, dust grain, scattering measurement 1
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Aliphatic polyester-based nanoparticles as drug delivery systems
Jäger, Alessandro ; Štěpánek, Petr (advisor) ; Sedláček, Jan (referee) ; Sikora, Antonín (referee)
Nanoparticles from biodegradable polymers are considered one of the most promising systems for biomedical application as drug delivery systems. Therefore, the synthesis and characterization of a new aliphatic biodegradable copolyester named PBS/PBDL (poly(butylene succinate-co- butylene dilinoleate)) intended to the application as drug delivery system is reported in the thesis. Surfactant-free biodegradable and narrowly distributed, nanosized spherical particles (RH < 60 nm) have been produced from the biodegradable material by applying a single-step nanoprecipitation protocol. The size of the generated polymer nanoparticles (PNPs) could be controlled by adjusting the polymer concentration, the choice of organic solvent, mixing different organic solvents or by changing temperature and ionic strength. By optimizing such parameters sub-100 nm uniform PNPs can be produced through this methodology including the advantage and ability to scale-up production. The nanoparticles structure was characterized in detail by employing a variety of scattering techniques and transmission electron microscopy (TEM). Combined static light scattering (SLS) and dynamic light scattering (DLS) measurements suggested that the nanoparticles comprise a porous core conferring them a non-compact characteristic. Their porosity...
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Nanoparticles based on complexes of hydrophilic block polyelectrolytes and new gemini ionic surfactants
Šomšáková, Katarína ; Uchman, Mariusz Marcin (advisor) ; Trhlíková, Olga (referee)
This bachelor thesis deals with preparation and study of the aqueous solutions of block polyelectrolyte poly(2-vinylpyridine)-b-poly(ethylen oxide), P2VP-PEO with gemini surfactants 6,6'-(ethan-1,2-diylbis(oxy)) bis(3-dodecylbenzenesulfonate acid), 6,6'- (buthan-1,4-diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) and 6,6'-(hexane-1,6- diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) complexes and with P2VP-PEO and sodium dodecylsulfate, SDS, complexes, and compares their physico-chemical properties. Formed particles were characterized by static and dynamic light scattering, zeta potential, isothermal titration calorimetry and transmission cryo-electron microscopy. Even small amount of surfactant leads to coassembly of P2VP-PEO with surfactants, formed by PEO shell and P2VP/surfactant core. The nanoparticles of block polyelectrolyte and gemini surfactants in 0.1M HCl are stable and their size depends on the spacer lenght and the surfactant/polymer ratio.
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Self-Assembly in Mixture of Surfactants and Stimuli-Responsive Polymers with Complex Architecture
Bogomolova, Anna ; Filippov, Sergej (advisor) ; Štěpánek, Miroslav (referee) ; Hanyková, Lenka (referee)
Title: Self-assembly in mixture of surfactants and stimuli-responsive polymers with complex architecture Author: Anna Bogomolova Department: Physical and Macromolecular Chemistry Supervisor: PhD. Sergey K. Filippov, IMC AS CR, v.v.i. Supervisor's e-mail address: filippov@imc.cas.cz Abstract: The issue of construction of complex multi-block copolymers is currently one of the most researched areas. It became a logic consequence of the continuous development in polymer chemistry. Nowadays, a great interest is attracted to multi- responsive block copolymers. As a rule, they consist of hydrophilic, hydrophobic and responsive blocks. That responsive block can be either thermo-sensitive or pH-sensitive as well as sensitive to some other external stimuli. In the present work, we will try to cover topic of stimuli-responsive block copolymers and their interactions with different types of surfactants. Understanding of polymer/surfactant interactions can be a crucial step for future modeling of drug/polymer or protein(DNA)/surfactant interactions. There is a great interest in the investigation of polymer-surfactant interactions. However, while the homopolymer-surfactant interactions are characterized well enough, the same interactions for block copolymers are poorly described. The main development in the latter topic...
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Proposal of ultrasonic trap
Bartoň, Petr ; Pavlů, Jiří (advisor) ; Vyšinka, Marek (referee)
Light scattering by dust grains is a complex problem when the size of the grain is about the wavelength of incident light. The Mie theory is often used to characterize such situtation, however, most of the materials lacks knowledge of neccessary material constants. Moreover, solution of Mie equations for general shapes is difficult and partly not known. Objective of this work is development of apparatus for light scattering measurements on small (micrometer ranged) ar- bitrary shaped dust grains levitating in the ultrasonic field. Trap parameters are obtained by survey of literature and by numeric simulations leading to design of reliable ultrasonic levitator including optical system. The results enable manu- facturing and completion of such apparatus. Eventually, this work can serve as guide "how to design ultrasonic levitator".
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Aerosol light scattering measurements
Novotná, Nikola ; Zíková, Naděžda (advisor) ; Klán, Miroslav (referee)
This thesis' objective is basic data processing of light scattering, which was measured using three-wavelength Integrating Nephelometer. Measurements were carried out at observatory in Košetice, where the nephelometer has been placed since mid-2012. The data collection was carried out during two calendar years (2013 and 2014) and the measurement still continues there. Data is processed in a manner to be suitable for using in future research in the field of meteorology and climatology. Basic parameters such as Angsroem exponent, average value, median and annual and daily cycles are calculated. All dependencies and cycles are graphically represented and commented. Besides other things, it was found out during the data processing that e.g. average coefficient of light scattering was very similar in both years or that the scattering coefficient was higher in winter months. In addition, the thesis discusses another options for future measurements. Key words: atmospheric aerosol, light scattering, nephelometer, Angstroem exponent
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Preparation and characterization of binding partners of phosducin.
Kylarová, Salome ; Obšil, Tomáš (advisor) ; Teisinger, Jan (referee)
AABBSSTTRRAACCTT Phosducin (Pdc) is a highly conserved acidic phosphoprotein, which plays an important role in the regulation of G-protein signalization in intact retina. It binds to Gβγ dimer of heterotrimeric G-protein transducin thereby decreases the pool of available transducin resulting in modulation of signal. Function of phosducin is negatively regulated by its phosphorylation followed by interaction with the 14-3-3 protein. Besides this established way of regulation, we were interested in other putative interaction partners of phosducin, like SUG1 and CRX. SUG1 is a subunit of 26S proteasome with a large scale of biological functions, especially a degradation of many transription factors. Its role in regulation of phosducin is still unclear, but is probably involved in targeting of phosducin to 26S proteasome for its degradation. Subsequently, we prepared four different expression constructs of full-length protein in order to find the best expression and purification strategy. These results suggest that all purified fusion proteins of SUG1 form stable and soluble high molecular weight oligomers. This behaviour was confirmed by dynamic light scattering and analytical ultracentrifugation measurements. In addition, this observation is consistent with previous studies of its bacterial counterpart, PAN...
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Photoprotective properties of PHB granules
Hesko, Ondrej ; Obruča, Stanislav (referee) ; Mravec, Filip (advisor)
The objective of this work is study and design of physical-chemical methods for verification of photoprotective properties PHB inclusions using bacteria Cupriavidus necator H16 and its mutated bacteria strain Cupriavidus necator PHB-4 which differs in production capability of polyhydroxyalkanoates. Basic information about of polymer inslusions and methods used for proving photoprotectivity are discussed in theoretical part. Methods such as nephelometry and continous fluorescence microphotolysis (CMF), which is used to characterize the mechanism of interaction of light with inclusions, were optimized. In experimental part properties of light scattering in bacteria were determined and characteristic curves were obtained. Further the photostability of fluorescence probe specific for nucleic acids were compared in bacteria strains. This method should prove bigger tolerance of bacteria H16 for UV light. It should also define possible interaction of nucleic acids with PHB inclusions.
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