National Repository of Grey Literature 89 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Analysis of Thick Film Amperometrical Sensors Signal and Its Usage for Measurement and Characterization of Enzymes
Ondruch, Vít ; Kizek, René (referee) ; Masojídek,, Jiří (referee) ; Vrba, Radimír (advisor)
V práci je popsán princip synchronní detekce (SD), který byl uplatněn při měření s biosenzory. Metoda SD umožňuje dosažení výrazně lepšího poměru signálu k šumu, vyššího limitu detekce a celkové zlepšení robustnosti měření. Uplatnění SD při měření s biosenzory umožní zlepšit analýzu jeho odezvy a umožní odstranění nežádoucích interferencí nebo šumů, které mohou být způsobeny například mícháním roztoku, elektromagnetickými vlivy nebo parazitními proudy. SD také umožňuje rozložit získaný signál na odezvu stimulace a na dlouhodobý signál jiného procesu, a dále také identifikovat jevy druhého řádu. Pro identifikaci stimulačního signálu ve výstupním signálu měření byl na základě lineárního statistického modelu vyvinut specializovaný software. SD byla ověřena na modelovém případu výstupního signálu biosenzoru s aplikovaným komplexem fotosystému II (PSII) a jeho odezvě na stimulaci světlem. Odezva PSII se řídí kinetikou prvního řádu a může být také ovlivněna inhibitory. Kinetické konstanty vazby herbicidu na PSII závisí lineárně na koncentraci herbicidu. To umožňuje jejich měření také při nízkých koncentracích herbicidu.
Inhibition of Hazardous Compounds in Alumino-Silicate Systems
Koplík, Jan ; Škvára, František (referee) ; Rovnaníková, Pavla (referee) ; Havlica, Jaromír (advisor)
The ability of alumino-silicate systems to immobilize hazardous compounds has been investigated since 1990s. The aim of this work is to develope alumino-silicate system (matrix) based on industrial waste products with ability to immobilize hazardous compounds (heavy metals). This ability of the matrix was confirmed by leaching tests based on the law 294/2005 Sb. Concentration of heavy metals in leachates was determined by ICP-MS method. Alumino-silicate system prepared in this work consists of high-temperature fly ash and blast furnace slag activated by mixture of alkaline activators (hydroxide and water glass). Matrixes were characterized by suitable analytic methods (XRD, SEM, FT-IR, DTA-TGA-EGA). The same analytic methods were used to describe the mechanism of immobilization of selected elements (Ba, Cu, Pb) in prepared systems.
Biofilm formation in probiotic cultures and its application in pharmacy
Ryšávka, Petr ; Obruča, Stanislav (referee) ; Vorlová, Lenka (referee) ; Márová, Ivana (advisor)
The work was comprehensively focused on the development of adhesive forms of probiotics in the form of a biofilm on combined carriers with a prebiotic component. The second part dealed with the influence of food on the multiplication and survival of selected types of probiotic bacteria. Subsequently, the effect of individualized probiotic supplements on changes in the human intestinal microbiome was monitored. Suitable adherent probiotic strains for biofilm formation were selected and tested. Methods have been introduced and different variants of carriers for culturing and binding bacteria have been tested. In vitro experiments verified the stability of biofilm stucture and its resistance to low pH, bile and antibiotics in comparison with the planktonic cell form. The antimicrobial effect of probiotic strains in the form of a biofilm was studied. The cultivation of the multispecies biofilm on the combined carrier was optimized and the stability of the biofilm and the final viability of probiotic bacteria were confirmed. Furthermore, the influence of various foods and beverages on the viability of probiotic bacteria was evaluated with emphasis on the simulation of passage through the gastrointestinal tract. Both models, solutions with standardised concentrations of alcohol, sugar, salts, proteins or different pH and different types of real foods and beverages were tested. The effect of food and beverages was tested on monocultures of Lactobacillus acidophilus, Bifidobacterium breve and on probiotic capsules containing a mixed culture of probiotic microorganisms. The survival of probiotics in various food matrices in the simulated gastrointestinal tract was quantitatively different. We managed to define foods suitable for supporting the multiplication of probiotic bacteria. A separate part of the work was focused on the targeted modulation of the intestinal microbiome by individualized probiotics that were prepared on the basis of molecular biological analyzes of the intestinal microbiome aimed at detecting the percentage of lactobacilli, bifidobacteria and phylum Firmicutes and Bacteroidetes. Personalized probiotic supplementation confirmed the positive effect of this approach on microbiome changes, especially on the increase of the content of lactobacilli, bifidobacteria and the overall diversity of the microbiome.
Leachability of Ba and Cr from alkali-activated matrices
Cába, Vladislav ; Hajzler, Jan (referee) ; Koplík, Jan (advisor)
The aim of this work is to determine the usability of alkaline activated matrices made from ashes to inhibition of barium and chrome. Ashes – fly ashes and ashes from fluidized bed combustion – were compared with cement used for inhibition. By using inductively coupled plasma atomic emmission spectrometer were determined concentrations of barium and chrome in leachates based on norm ČSN EN – 12457-4. In addition, images were taken on the scanning electron microscope and crystallographic spectra from X-ray crystalography were obtained to determine structure. The results show that ashes from fluidized bed combustion are suitable for inhibition of both barium and chrome, whereas fly ashes can not sustain these elements with such success.
Fixation of the lead in alkali activated materials based on different types of ashes
Cába, Vladislav ; Kalina, Lukáš (referee) ; Koplík, Jan (advisor)
The aim of this work was to develop an alkali activated matrix based mainly on fly ash, to determine the ability to fix lead in these matrices, the impact of added lead on mechanical properties and to reveal the way of lead fixation in these matrices. The matrices consisted mainly of fly ash (four from fluidized bed combustion, one pulverized coal combustion) with an admixture of blast furnace slag and sodium silicate as an activator. Lechates were prepared on the basis of the ČSN EN - 12457-4 standard, lead concentrations in them were measured using an atomic emission spectrometer with inductively coupled plasma. The strengths of the samples were measured after 28 days. Images, element maps and element spectra were taken to determine the structure using a scanning electron microscope with an electron dispersion spectrometer, the samples were analyzed on an infrared spectrometer with a Furier transform, X-ray diffraction analysis and electron spectroscopy for chemical analysis were also used. The individual measurements showed that lead is accumulated in the form of hydroxide. The impact of lead doping on strength of the matrix was different for individual samples. Matrices from both types of fly ash released minimal amounts of lead into leachates, so it is possible to use them to fixate lead.
Study of plasma jet effects on yeast
Trebulová, Kristína ; Skoumalová, Petra (referee) ; Krčma, František (advisor)
The purpose of this work is to study the effects of a 2.45 GHz microwave plasma jet on the yeast Candida glabrata. The microwave plasma was generated by a surfatron resonator and as a working gas pure argon at constant flow rate 5 Slm was used. Thanks to a high number of active particles generated in a low temperature plasma, this type of plasma has become highly popular, especially thanks to its bactericidal effects. However, its antifungal effects and mechanisms of fungal inactivation have still not been fully understood. Therefore, the study focuses on the antimycotic effects of the low temperature plasma in a form of a microwave discharge on Candida glabrata as a model yeast example. The principal focus is on the measurement and evaluation of changes in inactivation effects caused by varying the initial concentration of Candida glabrata cells, applied power, and the exposure time. The theoretical part presents the basic information concerning Candida glabrata, its pathogenicity, virulence and infectivity. Furthermore, plasma in general, various types of discharges and their applications in the food and biomedical industries are discussed. The experimental part focalizes on the determination of the inactivating effects of the microwave plasma jet on the yeast Candida glabrata. The experiment consists of applying the discharge on a freshly inoculated colony of Candida glabrata on agar plates and observing inhibitory effects in the form of inhibitory zones formed after subsequent cultivation. The inhibition of yeasts by the microwave discharge is interesting scientifically due to its promising results, which have also been proven in this work, but also economically, especially due to the use of argon. Argon as a carrier gas is much cheaper than helium and colder than common atmospheric pressure discharges in air such as DBDs, corona or glow discharges.
Utilization of thermal analysis in the study on effects of microbial inhibitors
Bošeľová, Miriam ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the use of thermal analysis in the study on effects of microbial inhibitors. The main aim of this work was to determine the utilization of the method, which is mainly used in different fields of science and research. Three bacterial strains: Cupriavidus necator H16, its mutant strain Cupriavidus necator PHB-4 and Halomonas halophila, were used as model microorganisms. The inhibitory effect of levulinic acid on growth and metabolic activity was monitored by microcalorimetry. It was found that bacteria were able to adapt to levulinic acid to a certain concentration - Cupriavidus necator to 5 g/l and Halomonas halophila to 2 g/l. The thermal analysis results were compared to a conventional method, which is commonly used to study the growth of microorganisms.
Expression and binding properties of human galectin-4
Friede, Tereza ; Bojarová, Pavla (advisor) ; Kavan, Daniel (referee)
Galectin-4, a member of the galectin family known for its affinity to β-galactosides, belongs to tandem-repeat galectins and consists of two distinct subunits connected with a peptide linker. Galectins play a key role in various biological processes and are involved in the pathogenesis of many diseases. Colorectal cancer (CRC) tissue shows a lower expression of galectin-4 compared to healthy colon tissues, and the lower expression of galectin-4 promotes tumor progression and transport. Galectin-4 was found to inhibit tumorigenesis of CRC cells via Wnt/β-catenin and IL-6/NF-κB/STAT3 signaling pathways, which play a key role in CRC development. In inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, galectin-4 interacts with CD4+ T lymphocytes, influencing their behavior in the immunological synapsis. Furthermore, galectin-4, primarily expressed in the gastrointestinal tract, participates in the apical transport in epithelial cells, promotes the healing of intestinal epithelial wounds, participates in the adaptive immune response and has multiple roles in the central nervous system. Studying inhibitors of galectin-4 helps to understand its specific roles in these processes, and thus to identify new potential therapeutic targets. In this work human galectin-4 was heterologously...
Studium změn antimikrobiální aktivity houby Ganoderma adspersum pomocí kultivační strategie OSMAC
Komárková, Lucie
Ganoderma adspersum is a white rot fungus that degrades lignocellulose in nature. However, it has also been proven to have many biological activities, including antioxidant, antitumor and anti-inflammatory. This study is focused on monitoring the antimicrobial activity of G. adspersum against the bacteria Escherichia coli, Staphylococcus aureus, MRSA and Klebsiella pneumoniae. First, the fungus was cultivated in three media with different additives. Using the minimum inhibitory concentration test, the effect of individual cultivation on viability was monitored. The lowest values were measured in YMB medium with tryptophan, which reduced the viability of E. coli up to 23 %. Based on this result, E. coli was chosen for growth curve, where media with additives were compared with pure media. It was found that pure media showed greater inhibitory activity than media with additives. The highest activity was observed in pure PDB medium, in which nearly 40% inhibition occurred at a concentration of 0,25 mg/ml. The results showed that Ganoderma adspersum could be a potential antimicrobial agent.
Synthesis of peptides as potential ligands of aspartate protease HIV and MAY1 and confirmation of their inhibitory activity
Klikarová, Ivana ; Šácha, Pavel (advisor) ; Žáková, Lenka (referee)
The lentivirus known as the human immunodeficiency virus (HIV) is transmitted through blood and body fluids, causing the destruction of CD4 lymphocytes and leading to opportunistic infections that define acquired immunodeficiency syndrome (AIDS). The urgent need for new antiretroviral drugs stems from concerns about the long-term toxicity of existing drugs, HIV-1 variants resistant to treatment, and frequent changes in patient treatment. Drug development is focused on inhibitors of two viral enzymes, reverse transcriptase and protease. Antiretroviral therapy uses protease inhibitors in combination with nucleoside analogs to effectively suppress viral replication, prolonging the lives of HIV-infected patients and reducing morbidity. Cryptococcus neoformans and cryptococcus gattii infections primarily affect the immunocompromised population and have high morbidity and mortality rates. Resistance to commonly used antifungals has been emerging, making it more difficult to treat these infections. Protease inhibitor components used in antiretroviral therapies have shown some clinical efficacy in these opportunistic infections, particularly in Major Aspartyl peptidase 1, an aspartate protease belonging to the same family of proteases as the HIV protease. To search for low molecular weight peptide ligands,...

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