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Behaviour of humic acids in aqueous solutions
Čechová, Eva ; Barančíková, Gabriela (referee) ; Klučáková, Martina (advisor)
Tato práce se zabývá chováním huminových kyselin ve vodných roztocích a to především jejich disociací a rozpustností. Disociace huminových kyselin byla studovaná jejich částečným rozpuštěním ve vodě a v roztocích solí o různých iontových silách. Analyzované huminové kyseliny pocházely jak z lignitických tak i půdních zdrojů a jedna z nich byla upravena plazmatem. Metodami použitými při experimentech byla potenciometrie, konduktomerie a UV/VIS spektroskopie. Podle Henderson-Hasselbalchovy závislosti byly vypočítány zdánlivé disociační konstanty. Dále byly určeny zdánlivé aktivitní koeficienty kyselých funkčních skupin. Poté byla studovaná rozpustnost huminových kyselin ve vodných roztocích solí. Byly sestrojeny závislosti pH hodnot, vodivostí a absorbancí jak na obsahu huminových kyselin ve vzorku tak na iontové síle roztoku. Studována byla také kinetika disociace huminových kyselin. Získaná data byla srovnána s navrženou hypotézou předpokládající několikakrokový mechanismus disociace huminových kyselin. Chovaní všech vzorků huminových kyselin odpovídalo navrženému mechanismu. Bylo potvrzeno, že stupeň disociace huminových kyselin ve vodných roztocích klesá s rostoucím obsahem huminové kyseliny stejně tak jako ve vodných roztocích solí s rostoucí iontovou silou.
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Dissociation behaviour of humic acids
Karbanová, Kateřina ; Kratochvílová, Romana (referee) ; Klučáková, Martina (advisor)
Humic acids are substances of natural origin and form the finest part of humic substances. They are formed by biochemical transformations of organic residues (mainly plants). They act as a weakly acidic polyelectrolytes with not exactly described structure. Their solubility is affected by pH value. The higher the pH value is the higher the solubility is. They are almost insoluble in acids. Bachelor thesis deals with the study of the dissociation behaviour of humic acids. Dissociation constant of humic acids is determined by three different methods – conductometric, spectrophotometric and combination of measurment pH and the content of acidic functional groups in Na2SO4. On the basis of results the methods are compared.
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Determination of content of humic acids in solutions chronopotentiometrically
Viktorinová, Jana ; Kislinger, Jiří (referee) ; Klučáková, Martina (advisor)
Humic acids are part of humic substances, which are substances of natural origin occurring in soil, peats, sediments and young coal. These substances are mixture of compounds with different molecular weight and structures. Humic acids are only partially soluble in aqueous solutions and their solubility is growing up with icreasing pH value. Bachelor thesis uses method of chronopotentiometric titration, which has not been used yet for humic research. This bachelor thesis is trying to check possibility of exercise this method for assessment concentration of soluble humic acid. Especially trace amounts of analyt are measured by this method. Results obtained by chronopotentiometric titration are compared with results in common used method as UV/VIS spetctromerty and potentiometry.
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Determination of pKa of humic acids by means of UV/VIS spectrometry
Kratochvílová, Romana ; Maršálek,, Roman (referee) ; Klučáková, Martina (advisor)
The behaviour of humic acids in aqueous solutions is closely connected to the content of acid functional groups and their dissociation abilities. The titration methods are the most often used for the research of acid-base characteristics of humic acids, their results should lead to the determination of the content of functional groups and their pKa. However the determined values depend on many factors including the titration speed. The spectrophotometric determination of dissociation constant was used in this diploma thesis. Reliability of this method was confirmed in bachelor thesis where is mentioned that spectrophotometric determination of pKa corresponds with realistic dissociation behaviour of humic acids in the water much more better than values obtained from titration methods. The principle of newly used spectrophotometry method is the preparation of humic acids solutions in three different media with different pH values. Acid groups of humic acids are practically completely dissociated in intensely basic environment and the measured absorbance is caused by anion of „humate“. On the contrary their dissociation in acid environment is suppressed so much that we measure the absorbance of non-dissociated molecules of humic acids. Deionized water was used like neutral solvent. Water was replaced by acetic buffer in this thesis because of water’s properties which have significant influence on solutions' pH. Buffer was used for diluting or for solubilisation and in these both cases more stable pH values were occurred. The aim of this diploma thesis is investigate UV/VIS spectra of various solutions of humic acids with different values of pH and determinate mean value of pKa of humic acids which could be used like comparison of dissociation behaviours for vary samples. Values of acid dissociation constant were determined from measured dates and compared with values obtained by titration method. The UV/VIS spectra gained in combination with the results of pH measuring and the conductivity next showed the differences in the behaviour of differently prepared samples of humic acids.
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Study of disassembly/reassembly mechanisms of ferritin protein cages and their utilization in nanomedicine
Krausová, Kateřina ; Fohlerová, Zdenka (referee) ; Heger, Zbyněk (advisor)
Diploma thesis deals with the study of dissociation and reassociation of ferritin protein cages and their use in nanomedicine. Most studies that are focused on targeted transport of pharmaceuticals using ferritin cages work with horse spleen ferritin. It is, however, its origin, which leads to increasingly frequent questions about possible immunogenicity in the patient's organism, which also provides the main motivation to test the possibility of encapsulation of low-molecular drugs into ferritins originating from alternative organisms. In the practical part the method for the study of dissociation was experimentally designed. Native polyacrylamide gel electrophoresis was used to study dissociation of equine ferritin composed of different subunit, human ferritin, and archeal Pyrococcus furiosus ferritin. The obtained subunit dissociation results were used to encapsulate the low molecular chemotherapeutic drug doxorubicin and for further characterization of the ferritin-doxorubicin complex. The efficacy of the designed nanoformulations has been verified in the treatment of malignant breast cancer. Human ferritin proves to be the optimal one. Its composition of heavy subunits corresponds to a lower protein stability, thus a more efficient opening of the structure and consequent encapsulation of the cytostatics occurs. With its 60% encapsulation efficiency of doxorubicin, low polydispersity index, effective cytotoxicity of ferritin-doxorubicin complex and minimal risk of immune response to the patient's organism, human ferritin achieves better results than commonly used horse spleen ferritin.
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Metane hydrate extraction
Hanzlík, Martin ; Brázdil, Marian (referee) ; Šnajdárek, Ladislav (advisor)
Thesis describes the chemical and physical properties of methane hydrate, the presence and location of sites in various types of sediment. Goal of this work is to evaluate the proposed production methods of methane hydrate from the technological, logistical and economic aspects. With the technologies currently available, the best production method is depressurization. There is a high probability that in the next decade it will be used for the production of natural gas from methane hydrate. The conclusion is evaluating areas with high potential for industrial production.
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Solubility and dissociation of humic acids
Kratochvílová, Romana ; Jaroslav,, Záhora (referee) ; Klučáková, Martina (advisor)
The behaviour of humic acids in aqueous solutions is closely connected to the content of acid functional groups and their dissociation abilities. The titration methods are the most often used for the research of acid-basic characteristics of humic acids, their results should lead to the determination of the content of functional groups and their pKa. However the determined values depend on many factors including the titration speed. The aim of this bachelor’s thesis is to verify the possibility of UV/VIS spectrophotometry´s use as alternative method for the determination of pKa of humic acids and to compare the gained results with so far used method according to Henderson-Hasselbach. The principle of newly used spectrophotometry method is the preparation of humic acids solutions in three different media with different pH values. Acid groups of humic acids are practically completely dissociated in intensely basic environment and the measured absorbance is caused by anion of „humate“. On the contrary their dissociation in acid environment is suppressed so much that we measure the absorbance of non-dissociated molecules of humic acids. It was found out that after the modification it was possible to use the spectrophotometry method for the determination of pKa of these substances, while the use of method was verified within the three different samples of humic acids. The optimal ratio humic acids – water and the extent of wavelength for measuring UV/VIS spectra were determined. It was proved that the values of pKa determinated by these methods better describe the real dissociation behaviour of humic acids in water than traditional Henderson-Hasselbach method. The UV/VIS spectra gained in combination with the results of pH measuring and the conductivity next showed the differences in the behaviour of differently prepared samples of humic acids.
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Dissociation behaviour of natural biocolloids
Karbanová, Kateřina ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on the study of dissociation behaviour of natural biocolloids, namely humic acids and fulvic acids. Humic and fulvic acids are natural, heterogeneous, high molecular weight substances which behave as weakly acidic polyelectrolytes and they have complex not exactly described structure. They are formed by biochemical transformations of organic residues (mainly plants). They are part of the soil, water, peat, sediments and coal. Solubility of humic acids is affected by pH value. The higher the pH value is the higher the solubility is. Fulvic acids are soluble in whole range of pH values. The aim of this diploma thesis is to determine the dissociation constant for the five kinds of humic acids and four kinds of fulvic acids, which have been isolated from various natural sources. These samples were purchased from IHSS. Dissociation constants were determined by the conductometric method and a combination of measurment pH and the content of acidic functional groups in Na2SO4. UV-VIS spectrophotometry method was used to characterize the quality of humic acids and fulvic acids.
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Eating disorder
Loudová, Libuše ; Šotolová, Eva (advisor) ; Mlčková, Marie (referee)
This thesis summarizes the multifactorial causes of eating disorders in the context of current socio-cultural determinants, with a special focus on children and adolescents. The theoretical background for this thesis, as specified in the introduction, is a general overview of the possible causes, occurrence, course, prognosis, and diagnostic criteria of eating disorders, with an emphasis on younger school age and adolescent age. The central topic of my Bachelor's thesis is a questionnaire-based survey of the knowledge, recognition abilities, interventions, general attitudes towards the issue, and the implementation of primary prevention of eating disorders among members of the teaching staff in the sixth to ninth grades of normal elementary schools. The secondary objective of the thesis is to provide statistical data for the last five years due to the increase in the number and hospitalization rate of paediatric and adolescent patients with eating disorders at the Clinic of Paediatric Psychiatry and the incidence of these disorders in combination with a dual diagnosis. The comparative method and a questionnaire were used in this thesis.
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Neuroimmune and endocrine correlates of stress response and dissociation in affective disorders
Bízik, Gustáv ; Bob, Petr (advisor) ; Horáček, Jiří (referee) ; Yamamotová, Anna (referee)
Depression and other mental disorders are the leading cause of disability worldwide and their burden has increased considerably over past decades. However, advances in psychopharmacology of psychiatric disorders are not in measure with this negativ trend. As a result, a large body of researchinpsychiatryandneurosciencestries to furtherourunderstanding of pathophysiologicalmechanismsunderlyingmooddisorders andothermentalillnesses in order to improve the efficacy of current treatments and to identify new therapeutic agents. According to current evidence, stress-related pathways and inflammation processes are directly involved in thedevelopment of depressive disorder andseveral other psychiatric conditions.Thestudy of the effects and consequences of stress exposure requires an interdisciplinary approach,taking into account specific aspects of the "inputs", such as chronic stress and traumatic experiences, and related psychological processes, with the crucial role of dissociation. Following these theoretical findings, the empirical research performed in two cohorts of inpatients with depressive disorder focused on immune and endocrine responses to stress and their relationship to psychopathological symptoms, specifically trauma-related symptoms, psychic and somatoform dissociation and depressive...
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