This work deals with the development and optimization of conditions of pretreatment of two industrial surface finishing baths containing chromium(III) ions and oxalic, maleic, acetic or citric acid and their electrophoretic analysis. Some model mixtures containing known amounts of components of industrial solutions have been made for simulation of complex matrices of the real samples. Prior to analysis a sample pre-treatment consisting of different dilution and addition of fluoride, hydroxide or EDTA anions as suitable agent releasing acid out of the stable chromium complex were studied. Determination of organic anions was accomplished by indirect UV detection at 350 nm with a reference at 230 nm. A commercially available background electrolyte, pH 5.7, was used for separation of analytes. The most appropriate pre-treatment to release acids have been achieved by precipitation of chromium(III) hydroxide. The method of standard additions was used for the quantification. The concentrations of oxalate and citrate in the real samples were calculated as 96,50 % (S.D. = 0,71 %) and 97,53 % (S.D. = 0,79 %), respectively, of declared amount. Satisfactory repeatabilities were obtained for both analytes with R.S.D. values (n = 5) for migration times lower than 0,51 %, R.S.D. for peak areas of oxalic acid were...

The electrochemic's behaviour of the bile acids (cholic, glycocholic, deoxycholic, ursodeoxycholic and lithocholic acid) was studied on the meniscus-modified silver solid amalgam electrode (m-AgSAE) by differential pulse voltammery. Bile acids provide in the solution of the Britton - Robinson buffer and methanol (9:1) in the pH range 3.0 to 12.0 a cathodal signal in the high negative potentials: cholic acid, deoxycholic acid, ursodeoxycholic acid and lithocholic acid about −1400 mV and glycocholic acid, which alone is the conjugate with glycine, about −1500 mV. Cholic acid, glycocholic acid, deoxycholic acid and ursodeoxycholic acid provide the highest peaks to pH 5.0, approximately in their pKa values. Lithocholic acid provides peaks from pH 7.0. It was demonstrated by the cyclic voltammetry that the electrochemical behavior is influenced by the adsorption of the bile acids to the electrode; presumed reaction at the working electrode - a reduction of a proton of a carboxylic group, is controlled by the diffusion and the process is quasireversible. Utilization of the electrochemical reduction of bile acids for the voltammetric determination does not seem very suitable. It has been proven that the presence of the methanol deteriorates the measuring results for glycocholic acid. In the presence of...

This work is concerned with lipidic substances, in particular vegetable oils, used as pigment binders or as a protective varnishes for finishing artwork. The introduction reviews the recent knowledge of this subject, in particular with respect to the identification of the most used drying oils, and of the methods to study their changes in the course of time. Both can be achieved using determination of the relative representation of fatty acids, most characteristic being the ratio of stearic/palmitic a oleic/palmitic acids. This parameter is changing as the artwork is getting older and the oils are drying. Because of the availability of the instrumentation needed, we have chosen the high- performance liquid chromatography method for further experimental work. The first step was optimalization of the analytical method by standards of fatty acids. For derivatization of fatty acids, reagents 2,4-dinitrophenylhydrazine and 2-nitrophenylhydrazine were examined. Whereas we were unable to get any results with the first one (the method based on the article: Bravo, B. et al., Talanta 64, 1329-1334, 2004) for unknown reasons, good results were obtained with the second one. Derivates of fatty acids have been analyzed by high performance liquid chromatography (HPLC) on column with revesed phase (C18). The...

This work was focused on the preparation of model stabilized phospholipid membranes formed on porous polycarbonate carrier. 1,2-dipalmitoyl-sn-glycero-3-phosphocholin was used for their formation in hydrophilic pores of polycarbonate carrier. For characterization of the formation of phospholipid layers, their changes and a study of transport processes, electrochemical impedance spectroscopy and voltammetry were used. Transport of cadmium and copper ions was studied in the presence and in the absence of ionophore calcimycin which was incorporated into the formed of phospholipid membrane. Because these ions are often bound in complexes with various substances, such as low molecular weight organic acids (LMWOAs), this work was also focused on the transport of copper and cadmium ions across the model phospholipid membranes in the presence of malic acid, citric acid and oxalic acid at different pH. Besides the use of ionophore, some pilot experiments were performed to realize the transfer of copper ions using two peptides, nisin and transportan 10. Formation of phospholipid membranes and the transport processes were characterized by two proposed electric equivalent circuits which correspond to the covered and to the uncovered polycarbobate carrier. Keywords: Phospholipids, Membranes, Ionophore, Peptid....

1 ABSTRACT: This study is dedicated to the study of nucleation of sulphuric acid and water, which presents the key process associated with secondary aerosol formation via gas to particle conversion. We investigated the nucleation rates, new aerosol particles formation and growth dynamics of newly nucleated particles. These processes were explored in both laboratory and field experiments. In the laboratory measurements, we explored the H2SO4 - H2O nucleation rates and growth rates of newly formed particles under well-defined conditions and we also investigated the effect of experimental conditions on particle growth dynamics. Furthermore, we proposed a model, which predicts the particle growth and accounts for condensation of H2SO4, H2O and NH3. The comparison of experimental growth rates with atmospheric ones was made and resulting implications of the chemical nature of compounds involved in the early growth of nucleated particles is also presented. To investigate the atmospheric H2SO4 - H2O nucleation and new particle formation, we analysed a two-year long dataset of particle number size distributions, obtained from a urban background station in Prague Suchdol. A special attention was given to a recently reported special feature of particle growth dynamics - a particle shrinkage following previous new...

A determination of corrosion inhibitors in engine coolants represent a difficult analytical problem due to their different physicochemical properties. Nowadays a lot of instrument methods are needed to determine them. The aim of this work was the development of methods for their determination using only one instrumentation. Capillary zone electrophoreses was chosen as a suitable technique. Three electrophoretic methods for three groups of corrosion inhibitors were developed. Firstly, method for determination of inorganic anions was developed in range from 5 to 50 ppm with limit of detection around 1 ppm. Background electrolyte contains sodium chromate, CTAB and CHES solution. Analytes were detected indirectly at 450 nm. Another method was for determination of organic acids anions. They were determined in range from 5 to 500 ppm. Limit of detection for each analyte was around 1 ppm. Measurement was made with PDC a CTAC water solution. Indirect detection was used for this determination at 350 nm. Last developed method can be use for determination of aryltrizoles in range from 5 to 500 ppm. Limit of detection was around 1 ppm. As a background electrolyte was used sodium tetraborate solution. The developed methods were validated and their suitability for determination of corrosion inhibitors in real...

Author: Nikola Jozefčeková Title: Endoglin and liver Form: Diploma Thesis University: Charles University, Faculty of Pharmacy in Hradec Králové Degree: Pharmacy This diploma thesis concludes the available information about endoglin, its isoforms in the liver and its impact on the liver during various pathological conditions. In the first part of the thesis describes morphology and physiology of the liver, its structure, histology and metabolic functions. Second part contains an information about endoglin, its isoforms and role in TGF-β signaling complex, expression of endoglin and regulation of the expression. In the third part are described liver diseases during which is expression of endoglin changed. This part deals with the significance of endoglin as a diagnostic and prognostic marker. Endoglin (CD105, TGF-β receptor III) is a homodimeric transmembrane glycoprotein and a membrane co-receptor TGF-β with high expression in endothelial cells. Endoglin plays an important role in the vascular development. Endoglin is involved in the processes of angiogenesis, vascular homeostasis and TGF-β signalization. It affects activity of TGF-βRII, ALK1 and ALK5 receptors. Due to the interactions with TGF-β complex, modulation of activity of ALK receptors and Smads, endoglin controls fibrotic and anti-...

Adipose tissue plays a crucial role in nutrient and energy homeostasis. At the time of worldwide pandemy of obesity and consequent metabolic syndrome, a great effort is made to find new treatments with potential to preserve insulin sensitivity, or even counteract development of obesity and type 2 diabetes. There are three principal possibilities how the adipose tissue biology can contribute to this goal: 1) induction of UCP1-dependent energy dissipation in brown adipose tissue; 2) conversion of white adipose depots to brown-like tissue (i.e. "browning"); and 3) stimulation of UCP1-independent thermogenesis in white adipose tissue. This thesis is based on two published works and one article under preparation. Generaly, it is focused on three different approaches targeting the above mentioned processes in adipose tissue of laboratory mouse: 1) diet supplementation with bile acids; 2) combination treatment of ω-3 polyunsaturated fatty acids and calorie restriction; and 3) cold exposure. In the experiments with administration of bile (specifically chenodeoxycholic) acid to mice, we confirm specific induction of UCP1 in both brown and subcutaneous white adipose tissue, as well as reversion of obesity in the response to the treatment. Nevertheless, most of the acute beneficial effects are mediated by...

This thesis is focused on the development of an analytical method for the determination of volatile fatty acids in aqueous samples using GC-MS/MS. The theoretical section provides general information on a selected group of acids, their significance in the biogas plants, the means of their derivatization and the analytical techniques used. The practical part mainly deals with optimizition of various parameters in the derivatization reaction to achieve optimal conditions. Finally, the analytical method was successfully validated and applied to the analysis of a real sample.

Well functioning circadian system is crucial component of healthy organism and its disruption can result in impairment of metabolic functions with consequential development of obesity and type 2 diabetes mellitus. Obesity is in general caused by enhanced migration of pro- inflammatory polarized macrophages (M1) into adipose tissue. We have shown, that interaction of this type of macrophages with adipose tissue had significant effect on rhythmic expression of clock genes in adipocytes. We further investigated effect of high fat diet and diet enriched by omega-3 fatty acids on circadian oscillations in WAT and differently polarized macrophages. This diet affected oscillations in adipose tissue and in M0 and M2 polarized macrophages. These results support previous findings of effect of omega-3 fatty acids on metabolism and suggest their effect on circadian system as well. Key words: circadian rhythms, adipose tissue, macrophages, omega-3 fatty acids, high fat diet