National Repository of Grey Literature 391 records found  beginprevious21 - 30nextend  jump to record: Search took 0.02 seconds. 
Inverse FCS in colloidal systems research
Richterová, Veronika ; Venerová, Tereza (referee) ; Mravec, Filip (advisor)
This diploma thesis is focused on the study of inverse fluorescence correlation spectroscopy, especially with the regard for the usage of different fluorescent probes and different sized analysed particles. At first, the proper concentration of fluorescent probes was determined. In this concentration is the probe considered as a medium surrounding the analysed particles. Based on this concentration, which was determined as 400 M, several sets of samples were prepared. This samples contained different concentration of polystyrene particles of 100 and 500 nm diameter and multilamellar liposomes. Then, the FCS curves of samples with different fluorescent probes were measured. Fluorescein, rhodamine 6G and Atto 488 were used as fluorescent probes. As a result from experiments, it was found, that particles with 100 nm diameter cannot be analysed with none of the fluorescent probes. Inverse FCS method can be applied to systems, that contains particles with 500 nm diameter and fluorescein. Systems with rhodamine 6G have the same behaviour as typical FCS measurement. It is caused by dimerization of this probe and it cannot be used for 500 nm particles. Liposome samples can be established with iFCS method, but the results are biased by random distribution of liposomes size.
Ruthenium-based nanoparticles and testing of their anticancer activity
Žáková, Eliška ; Fohlerová, Zdenka (referee) ; Heger,, Zbyněk (advisor)
Neoplastic diseases hold the second place of the most common causes of death worldwide. Available treatments include various combinations of surgery, chemotherapy, radiation, hormone therapy, immune therapy and targeted therapy. The emphasis is currently laid on nanomedicine, where new nanosized complexes are developed and applied for the targeted treatment and chemotherapy. The aim is to significantly improve the anticancer effect and decrease the damage to organism. In this thesis, ruthenium nanoparticles with a size of 12–14 nm were synthesized and their surface modified with polyvinylpyrrolidone. Furthermore these were subsequently modified with polyoxyethylene(40)stearate for binding of doxorubicin. These nanoparticles were tested on breast carcinoma cells (MDA-MB-231), ovarian carcinoma cells (A2780) and neuroblastoma cells (UKF-NB-4). Apoptosis and necrosis testing showed 60—64 % increase in apoptosis when comparing ruthenium nanoparticles modified with doxorubicin to nonmodified ruthenium nanoparticles. The modification increased level of oxidative stress in tumorous cells and slightly a genotoxicity to non-tumorous cells, nevertheless the hemocompatibility was significantly improved. Testing has proven with IC50 0.98 g/ml, 3.91 g/ml and 1.95 g/ml higher sensitivity to these cells and confirmed expected anticancer activity. Compared to one of the most common chemotherapeutic agents cisplatin the modified ruthenium nanoparticles are significantly more toxic to cell lines A2780 (IC50=21 µg/ml), MDA-MB-231 (IC50=9 µg/ml) and UKF-NB-4 (IC50=4 µg/ml).
Self-cleaning Properties of Thin Printed Layers of Titanium Dioxide
Králová, Marcela ; Brezová, Vlasta (referee) ; Krýsa, Josef (referee) ; Veselý, Michal (advisor)
Tenké vrstvy oxidu titaničitého byly imobilizovány na sodnovápenatá skla a skelný uhlík použitím jak techniky materiálového tisku tak metodou chemického napařování. Pro přípravu titaničitých solů byly použity metody sol-gelu a nebo hydrotermální syntézy. Struktura připravených vrstev byla zkoumána rastrovací elektronovou mikroskopií a mikroskopií atomárních sil. Krystalická struktura připravených TiO2 byla analyzovány pomocí XRD metody. Fotoindukováná superhidrofility pripravených vzorků byla charakterizována měřením kontaktních úhlů. Fotokatalytická aktivity připravených vzorků byla testována na fotokatalytické oxidaci 2,6-dichlorindofenolu a kyseliny mravenčí. V případě sol-gel vrstev byl zkoumán vliv množství naneseného TiO2 a množství PEG, který byl do solu přidán jako praskliny potlačující činidlo. V případě hydrotermálních vrstev byl zkoumán vliv času a teploty syntézy a množství vrstev na výslednou účinnost vzorku. U chemicky napařených vzorků byl zjišťován vliv intenzity záření. Byla porovnána fotokatalitická aktivita vrstev připravených materiálovým tiskem a chemickým napařováním a byl vyhodnocen nejaktivnější vzorek.
Exposure to Nanoparticles in Means of Transport
Maslonková, Ivana ; Kadlec, Radek (referee) ; Adamec, Vladimír (advisor)
The diploma thesis deals with the exposure of nanoparticles in means of transport. The diploma thesis provides an overview of the current state of exposure to nanoparticles in vehicles that people use every day travelling to work. Moreover, the work describes the health risks that can be caused by these particles and have an adverse effect on human health. The work processed data (particle number concentration, particle size and LDSA) which monitored the exposure of nanoparticles in the tram of public transport in the city of Brno and the extent of pollution by nanoparticles at stops.
Transfection of somatic cells using magnetic nanoparticles and their post-transfection localization
Pošustová, Veronika ; Skopalík, Josef (referee) ; Svoboda, Ondřej (advisor)
This bachelor thesis is focused on an experiment based on magnetic particles SPIO for transfection of 3T3 cells. Nanoparticle surface was modified with PEI and Chitosan to optimize this method. The transfection experiment was performed twelve times, then the scanned data was processed and statistically analyzed in Matlab R2016a to determine the transfection efficiency. The theoretical part is focused on magnetic nanoparticles and their application in medicine, on transfection and in last part on a transfection of cells using magnetic nanoparticles.
Preparation and application of nanoparticles and nanofibres with natural UV filters
Plachá, Monika ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
The presented diploma thesis is focused on preparation of nanoparticles and nanofibres with natural UV filters. Liposomes with encapsulated aqueous, ethanol and lipid extracts were prepared. Nanofibers from PHB containing lipid extract were prepared too. As a part of this work, an overview of natural sources with potential effects as UV filters were introduced. Moreover, nanoparticles and nanofibers and methods of their characterization were described. Size, polydisperse index and colloid stability of prepared nanoparticles were characterized via DLS. In experimental part aqueous, ethanol and lipid extracts were prepared from roasted coffee, green coffee and cascara. These extracts were spectrophotometrically characterized for the content of polyphenols, flavonoids, antioxidant activity, tannins and their SPF. Liposomes and liposomes containing PHB with these extracts were prepared and the encapsulation effectivity, short–term and long–term stability as well as SPF of nanoparticles were determined. Nanofibers from PHB containing lipid extracts were prepared via electrospinning and forcespinning methods. Prepared nanofibers were examined via FTIR–ATR. Antioxidant activity, short–term and long–term stability were determined spectrophotometrically. From selected nanoparticles, emulsions and gels were prepared and their SPF was also determined. Three types of emulsions with the best SPF were selected and tested on volunteers. Sedimentation stability of emulsions was tested by analytical centrifuge. Finally, cytotoxicity of selected nanoparticles and nanofibers was tested via MTT assay using human keratinocytes.
Application of high resolution transmission electron microscopy for structure analysis of nanowires
Kachtík, Lukáš ; Sháněl, Ondřej (referee) ; Kolíbal, Miroslav (advisor)
This diploma thesis deals with the structural analysis of semiconductor nanowires by transmission electron microscopy. The construction of microscope is introduced together with its basic imaging modes and with the function of each construction element in these modes. In the experimental part the results of analysis of several germnaium nanowires are discussed, with emphasis on their crystallographic structure and orientation.
Nanosafety and the Current Trends in the Risk Assessment of Nanoparticles
Valovič, Stela ; Poláčik, Ján (referee) ; Adamec, Vladimír (advisor)
This diploma thesis deals with the current state of nanosafety. The aim of this paper was to review and critically analyze approaches to facilitate the risk assassment of nanomaterials. In the first part it provides an overview of the most important methods and software tools that are used in this field. Methods were analyzed against a set of relevant criteria. Criteria include consideration of exposure, life cycle and physicochemical properties, transparency, applicability and the field of application. Different criteria were chosen for the software tools. Based on results, a new approach was suggested. The approach takes the form of a diagram based on questions. The purpose of the suggested approach is to recommend the most relevant method, tool or their combination to assess the safety of a nanomaterial depending on known characteristics. The approach was also implemented in a software tool.
Design of colagen capilary beds phantom for cells accumulation testing and blood vessels blocation
Eichner, Dominik ; Skopalík, Josef (referee) ; Čmiel, Vratislav (advisor)
This bacalor thesis describes the adhesion of cells marked with iron nanoparticles to the capillary wall which is exposed to magnetic force. First, it characterize the bloodstream and speed of flowing blood. It also discusses the general characteristic of the nanoparticles useful in medicine, description of used microscopes and lastly proper methods of cultivation cells in vitro. The practical part tests the adhesion of the cells at different speeds, in different sized capillaries using magnetic forces.
Cereals - Active Substances, Biological Effects and Selected Applications in Food Industry
Lichnová, Andrea ; Tremlová, Bohuslava (referee) ; Vávrová, Milada (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on the study of the biological effects of active compounds found in cereals, on the development of methods of analysis these effects, on the determination of the content of active substances and characterization of the relationship between composition and biological effects of cereals and cereal products. For the analysis several kinds of raw cereal samples (flakes, flour, germ, bran), flavored extruded cereal products and also samples of paddy and husked rice were chosen. To major types of analysed active compounds belong mainly phenolic compounds in the form of glycosides and aglycones, and also saccharides. Group parameters such as total polyphenols, flavonoids and total and reducing saccharides were determined spectrophotometrically, individual phenolics and saccharides were determined by high performance liquid chromatography (HPLC). TEAC, DPPH and CLAMS methods were used to determine the antioxidant activity. Indirect methods of determination of substances with antioxidant effect were used as well. Results of the total antioxidant activity were compared with values of antimutagenic/genotoxic activity obtained by several microbial test systems. Antimutagenic effect was expressed as a percentage of inhibition of effect of standard mutagen and could be considered as a potential preventive effect of cereals to DNA arising primarily by free radicals effect. The highest values of group and individual phenolics, antioxidant and antimutagenic activity were found in germs, bran, in buckwheat products and in coloured and raw rice. In flavoured cereal products addition of chocolate or fruit positively influences content of active phenolic substances as well as sugars, antixidant and antimutagenic activity. In a representative sample of Czech population, questionnairy study was performed to monitor interest in cereals and consumer preferences. The most of consumers consider cereals with chocolate flavour as less healthy than confirmed results of laboratory analyses. In this study some new food products were developed. Several types of model cereal products containing plant (fruit, vegetables) extracts were proposed. Extracts were added to cereals in freeze-dried and encapsulated form. The highest positive effect exhibited addition of local forrest fruit extract. Within preparation of encapsulated extracts several methods of preparing lipid or saccharides particles were also tested. The encapsulation efficiency of the methods and stability and size of particles were analysed. Optimal type of fortified cereal foods could be suggested based on the acquired results. Selected cereals were used as alternative carbon substrates (processed or raw) for the cultivation of microorganisms to produce enriched biomass usable in the feed industry. We can conclude that cereals in raw as well as processed form belong to universal foods and rich sources of biologically active substances. They can be processed by many ways. They can be used for direct consumption, as a part of new products and also undirectly as a substrate for feedstock.

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