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Characterisation and elimination of compounds difficult to remove during water treatment
Čermáková, Lenka ; Pivokonský, Martin (advisor) ; Sochorová, Helena (referee) ; Brányik, Tomáš (referee)
The Ph.D. thesis deals with the characterization of algal organic matter (AOM), which is difficult to remove in water treatment, and on the basis of AOM character, various methods for its elimination, e.g. coagulation, oxidation with subsequent coagulation and adsorption onto activated carbon are assesed. Special emphasis is placed on identifying the optimal conditions of the processes and on describing the mechanisms and interactions involved. In terms of anthropogenic micropollutants, the thesis deals with the highly topical issue of the occurrence of microplastics in water. It was found that the removal efficiency of the individual AOM components varies substantially depending on the elimination method used. The identified optimum conditions of individual methods and especially the mechanisms that apply to the removal of target substances varied widely. The non-proteinaceous fraction of AOM was removed with very low efficiency (max. 25%) by conventional coagulation even under optimized conditions (pH 6.6- 7.5 for aluminium sulfate as the coagulating agent and pH 7.5-9.0 for polyaluminium chloride) and it was given by the high content of low molecular weight (LMW) substances that are difficult to coagulate. The dominant coagulation mechanism was adsorption onto aluminium hydroxide precipitates....
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Design, fabrication and testing of graphene biosensors
Tripský, Andrej ; Gablech, Imrich (referee) ; Bartošík, Miroslav (advisor)
Pokrok ve vývoji nanotechnologií nám poskytuje dobrou příležitost k vývoji nových špičkových zařízení. Tato práce si klade za cíl vyrobit, popsat a změřit grafenové pH senzory na dvou různých substrátech - polymeru parylenu C a SiO2. Tento pH senzor je prvním krokem ve vývoji nositelné náplasti monitorující stav kůže a možné infekce. Grafen je 2D materiál na bázi uhlíku se zajímavými vlastnosti a nadějnými aplikacemi. Úspěšně jsme provedli dva různé experimenty sloužící k charakterizaci grafenových senzorů a jejich odezvu na různé hodnoty pH. V prvním experimentu jsme použili horní elektrolytické hradlo k určení bodu neutrality (Diracův bod). Druhý experiment popsal změnu rezistence grafenu jako funkce pH. Dále jsme také funkcionalizovali grafen polyanilinem, abychom zlepšili jeho vlastnosti. Prokázali jsme citlivost grafenových senzorů na pH pro oba substráty a objevili jsme několik výzev jako potřebu kontroly iontové síly, experimentů samotných a destrukce grafenu.
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Zero Ionic Strength Corrections of pKA Constants and Electrophoretic Mobilities of Weak Electrolytes
Lorinčíková, Kateřina ; Gaš, Bohuslav (advisor) ; Sobotníková, Jana (referee)
The dependencies of the electrophoretic mobility of histidine on pH were measured in two sets of buffers at 20mM ionic strength. The parameters, which were obtained from these curves, were subsequently corrected to zero ionic strength using an older approach, as well as using the newly developed program AnglerFish. The effect of the ionic atmosphere on the pKA and mobility is shown, as well as the shape of the relevant corrections, which allow the determination of the pKA and mobility at infinite dilution. A new compound, imatinib, which is a quadruple positively charged nitrogenous heterocyclic compound, was also measured, and its pKA constants and mobilities were likewise determined. Key Words capillary zone electrophoresis, ionic strength, limiting mobility, pKA, zero ionic strength corrections
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ADSORPTION OF ALGAL ORGANIC MATTER PRODUCED BY MICROCYSTIS AERUGINOSA ONTO ACTIVATED CARBON
Krsová, Magdalena ; Pivokonský, Martin (advisor) ; Benešová, Libuše (referee)
The aim of this diploma thesis is to evaluate the efficiency of two types of granular activated carbon (GAC), Filtrasorb TL 830 and Picabiol 12x40, for the adsorption of cellular peptides with low molecular weight produced by cyanobacterium Microcystis aeruginosa that are hardly removable during the coagulation/flocculation processes. The effect of different carbon properties (surface charge, textural characteristics), peptide properties (molecular size, surface functionality and charge) and solution characteristics (ionic strength and pH value) on the peptide uptake was investigated using laboratory equilibrium and kinetic adsorption experiments. The results showed that adsorption of peptides was influenced by the charge conditions in adsorption system that depend on solution pH. The pH value influences surface charge and the point of zero charge (pHpzc) of GAC as well as dissociation and protonization of peptide functional groups. It was found that efficiency of the peptide adsorption increased with decreasing pH value for both GACs. Under these conditions adsorption was enhanced by attractive electrostatic interactions between GAC surface and peptide functional groups and was also positively influenced by the conformation changes in peptide structure. GAC Picabiol 12x40 showed the total highest...
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Modulation of HIV-1 Protease Activity
Pokorná, Jana ; Konvalinka, Jan (advisor) ; Šedo, Aleksi (referee) ; Ruml, Tomáš (referee)
HIV-1 protease plays a crucial role in the late state of the life cycle of HIV virus when it cleaves the viral polyprotein precursors into the structural and functional proteins. If it is effectively inhibited, HIV particles remain immature and noninfectious. The application of highly active antiretroviral therapy (HAART) including protease inhibitors can reduce plasma HIV-1 levels below the detection limit in adherent patients and thus dramatically change their life expectancy. The clinical utility of the first inhibitors was limited by severe side effects, low bioavailability, high pill burdens, and rapid development of viral resistance under the selection pressure of HIV antiretrovirals. To overcome these difficulties, second-generation inhibitors were developed. Despite an indisputable improvement they brought to antiretroviral therapy, the development of new highly active HIV-1 protease inhibitors with optimal pharmacokinetic properties, higher metabolic stability, little off-target activity, and particularly, more favorable resistance profiles is still of high importance. This thesis provides an overview of anti-HIV- drugs including development of substituted metallacarboranes, a new class of potent, unusual, nonpeptidic HIV protease inhibitors with therapeutic potential. Next, the impact of...
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Determination of stability constants of charged cyclodextrine complexes by capillary electrophoresis
Beneš, Martin ; Dubský, Pavel (referee) ; Zusková, Iva (advisor)
Martin Beneš Determination of stability constants of charged cyclodextrin comlexes by capillary electrophoresis Abstract Stability constant characterizes binding interaction between an analyte and complexation agent. These interactions play very important role in separation processes of, in other way undistinguishable, compounds, e.g. enantiomers. The most widely used complexation agents are cyclodextrins. Affinity capillary electrophoresis (ACE) belongs to methods suitable for the determination of stability constants. The stability constant is determined from the dependence of the effective mobility of analyte on the increasing concentration of complexation agent in background electrolyte (BGE). If charged CDs are used, the attention must be paid not only to viscosity of the BGE and to the influence of Joule heating on the temperature in the capillary but also to the increasing ionic strength. The thermodynamic stability constants of R,R- and S,S-hydrobenzoin and R- and S-(3-brom- 2-methyl-1-propanol) with cationic modified β-cyclodextrin: 6-monodeoxy-6-mono(3- hydroxy)propylamino-β-cyclodextrin hydrochlorid (PABCD) were determined by affinity capillary electrophoresis. The average temperature (25řC) of the BGE in the capillary was kept constant. This was achieved by decreasing of the cassette temperature...
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A novel way of preparing hydrogels
Kratochvílová, Olga ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This work is focused on testing the effect of ionic strength on the preparation of hydrogels prepared by phase separation hylauronanu polyelectrolyte solution (Hya) with cationic surfactant cetyltrimethylammonium bromide (CTAB) called „dry way“. In this case, there is a mixing of the polymer and the surfactant in the dry form and then added to the dispersion medium. With observation and rheology, the effects of the proportion of the components for the formation of the hydrogel. It was found that the higher the ionic strength causes the hydrogel has a lower viscosity and a more fluid. Tthis fact was confirmed from the results of rheological measurements. The gel with the ionic strength of 1 M is less viscous to gel the ionic strength of 0,5 M. Next, the purity of the hydrogel was observed, and it was found that hydrogels with the ionic strength of 0,15 M are clear without the use of centrifugation. In case of getting gel of the specific ionic forces of 0,15 M and 0,3 M formed by addition of multivalent cations/anions from observations we can say that the ionic strength in the case of the method of preparation of gels does not matter.
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Fluorescence study of hydrophilic domains of associating colloids
Londinová, Monika ; Knotková,, Kateřina (referee) ; Pekař, Miloslav (advisor)
The properties of the hyaluronan were investigated by using different fluorescence probes, because hyaluronan is a hopeful carrier of an active matter in medicine and cosmetics. Selected fluorescence probes were: cationic acridine orange, Nile Blue A, methylene blue, amphiphilic 4-Di-2-ASP and anionic fluorescein. Except from fluorescence and absorption spectra of the probes were observed electrostatic and hydrophobic interactions as well. The probes in solvents with different polarity (MeOH, EtOH, DMSO) showed the bathochromic shift in the emission maximum and quenching of the fluorescence with the increasing polarity of the solvents. The influence of the ionic strength on fluorescence properties of the probe acridine orange and 4-Di-2-ASP was investigated in aqueous solutions of chlorides. The formation of acridine orange dimer is inhibited with increasing ionic strength. CaCl2 increased the ionic strength the most, then prevented repulsion of carboxylate groups, so it means the expansion of hyaluronan cluster into the solution. However, the emission of the probe 4-Di-2-ASP was quenched with the addition of CaCl2 the most. The first additions of COO– groups cause the formation of dimers of AO shown as decreasing in extinction coefficient and fluorescence intensity. Next addition of the hyaluronan caused a depolymerization of formed dimers and the increase of the emission intensity. The repolymerization caused the decrease and then again the increase. In case of 4-Di-2-ASP was the pattern of the fluorescence (the intensity and the position of the emission) firstly the same, but at the concentration of 1 g dm-3 the emission intensity increased. The probes MB and F were used for spectroscopic studies of the interaction between methylene blue-fluorescein complex and anionic and cationic surfactants. The absorbance of separate MB and F changed only with the addition of surfactants with the opposite electric charge. Absorbance of the mixture MB-F changed with the addition of the CTAC surfactant, while the addition of SDS into the mixture caused only the change of MB absorption spectra.
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Dynamic light scattering and electroanalytical investigation of hyaluronan-amino acids systems
Muchová, Johana ; Kalina, Michal (referee) ; Chytil, Martin (advisor)
The bachelor thesis deals with interactions between low-molecular and high-molecular weight hyaluronic acid (HA) and protonized amphiphilic amino acids Lysine and Arginine. The interactions were observed in the area of low aminoacids concentrations with in the range 0–15 mmoldm-3. The interactions occur between the carboxyl groups of HA and the amino group of the protonated amino acids. Proving these interactions would allow us to physically modify HA and further more, use such a system as a carrier of pharmaceuticals. The resistence towards the ionic strength at the concentration of 0,015 and 0,15 moldm-3 NaCl was investigated. Previous results show that the system with unprotonated amino acids at low concetrations of electrolyte in the solution is rather disturbing. Therefore, the interactions were reinforced by the aminoacids protonation using HCl. The amino acids were protonated not only completely, but also partly because of negative influence of chloride anions. To study the interactions pH-metry, conductance and Dynamic Light Scattering were used.
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Microviscosity probes in study of aggregation in a biopolymer-surfactant system.
Vašíčková, Kamila ; Vala, Martin (referee) ; Mravec, Filip (advisor)
The effect of cationic surfactant concentration and ionic strength on anisotropy of fluorescence of probes diphenylhexatrien and fluorescein has been investigated in the system of cationic surfactant and in the system of cationic surfactant and hyaluronan. The investigation has been done by fluorescence emission spectroscopy. Obtained anisotropy gives information about microviscosity of investigated systems. Subsequently the system of cationic surfactant and hyaluronan has been investigated by 9-(2-carboxy-2cyanovinyl)julolidine, 4-(dicyanovinyl)julolidine and 1,3-bispyrenylpropane probes. The information about the microviscosity of the system gives the integral under the emission curve of 9-(2-carboxy2-cyanovinyl)julolidine and 4-(dicyanovinyl)julolidine and the ratio between excimer and monomer of 1,3-bispyrenylpropane. It has been discovered that the ionic strength influences the anisotropy of diphenylhexatrien and fluorescein only in the fist addition of salt (concentration 0,025 mol dm-3) and that addition of hyaluronan influences the anisotropy of diphenylhexatrien and fluorescein only in samples without addition of salt. Results of measurment with 9-(2-carboxy2-cyanovinyl)julolidine and 4(dicyanovinyl)julolidine describe the formation of aggregates of catinoc surfactant with hyaluronan and characterize these aggregates from the point of microviscosity.
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