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Effect of glucose on the corrosion behaviour of AZ31 magnesium alloy in saline solution
Faltýnková, Denisa ; Hasoňová, Michaela (referee) ; Doskočil, Leoš (advisor)
This bachelor thesis deals with the influence of glucose concentration on corrosion behaviour of magnesium alloy AZ31 in saline solution. The theoretical part briefly summarises the use of magnesium and its alloys in biomedical applications and offers insight into the current state of knowledge of the effect of glucose on corrosion of these materials. In the experimental part, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the electrochemical behaviour of AZ31 alloy in saline solution with varying concentrations of glucose. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterise post-corrosion surface of the alloy. The corrosion environment was analysed by measurement of conductivity, pH, inductively coupled plasma atomic emission spectroscopy (ICP-OES) and liquid chromatography with conductivity detector. Results showed that glucose, depending on concentration, impairs corrosion resistance of AZ31 alloy in 0.9% NaCl. Three organic acids were identified in the corrosion environment, of which gluconic acid is the most abundant.
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Chromatographic determination of simple sugars in selected beverages
Jurečková, Zuzana ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
An important part of the drinks are simple carbohydrates, because this thesis focuses on this issue. The theoretical part describes the characteristics , production , metabolism and the use of simple carbohydrates such as glucose, fructose and sucrose. There is also the definition of drinks and their main divisions . The literature review is based on the experimental part of analyzing selected beverages by high performance liquid chromatography with refractometric detection coupled to columns or alkyl ion-exchange phases. In conclusion, the results were compared to determine and comment . Nowadays the emphasis is on the correct functioning of the digestive tract. An important factor that supports the intestinal microflora is a prebiotic carbohydrate - tagatosa This could become tagatosa whose properties , production, metabolism in the body and any use is also included in the search . In the experimental part is listed possible optimization analysis of samples containing tagatosy on both types of columns in the HPLC system. The result is again commented in conclusion.
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Optimization of HPLC-ELSD method for determination of sugars in foods
Laba, Marija ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This master's thesis deals with the optimalization of HPLC-ELSD method for the determination of carbohydrates in food. The theoretical part focuses on the classification and characterization of carbohydrates, the occurrence of carbohydrates in food and their physiological importance. There was targeted mainly glucose, fructose, sucrose and maltose. There is a brief summary of the analytical methods that can be used to determine carbohydrates. Experimental part is based on a literary review. It also deals with high performance liquid chromatography with evaporative light scattering detector. The main content in this part is the optimalization of condition for reliable and rapid separation of the most frequently occurring carbohydrates in foods. The carbohydrates were identified and quantified under optimum condition in real samples specifically in fruit juice, beer, ketchup and red pepper powder. The result is commented in conclusion.
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3D tisknuté sensory pro detekci cukru v nápojích
Zichová, Anežka
Sugars are one of the most common ingredients in food industry, due to their diverse usage as technological component as well as sweetening element. The issue of sugar utilization is not only topic of food industry but plays a key role in human nutrition at the same time. The intake of simple sugars from food, particularly from sweetened beverages, is a major concern from a nutritional standpoint. Carbohydrates can be detected in variety of ways. A literature review was conducted on the methods used in food science, which is based on the previous characterization of the most frequently used sugars in food industry like sucrose, maltose, glucose, fructose, inverted sugar, and glucose-fructose syrup. The chemical, technological and nutritional properties of carbohydrates were described. Considering this examination, 3D printed electrodes were designed for detection of sugar, namely glucose, in beverages. In consideration of the available literature, electrochemical enzymatic biosensors were designed, using glucose oxidase as the sensing element to detect glucose in beverages. The electrodes, carrying the enzyme, were printed from PLA and graphene based conductive filaments. The electrodes were activated in chemical and electrochemical way. To bind the enzyme, a technique based on cross-linking and immobilization was used. Chronoamperometry and cyclic voltammetry were used to test the biosensor. Afterwards the real sample of a fruit juice-based non-alcoholic beverage was examined. The results were interpreted in the context of the applicable legislation of the European Union and, likewise, the legislation of the Czech Republic, in regard to the required data on food labels.
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The role of fructose in hepatic fat accumulation
Justrová, Marie ; Kovář, Jan (advisor) ; Malínská, Hana (referee)
One of the metabolic disorders with an increasing incidence is non-alcoholic fatty liver disease (NAFLD). NAFLD is characterized by pathological accumulation of fat in the liver. According to some authors, excessive fructose consumption plays an important role in its pathogenesis. The thesis aims to interpret published findings of the relationship between fructose intake and fat deposition in the liver. In the first part the fructose metabolism is described and compared with the glucose metabolism. The other effects of fructose on fat, carbohydrate and nucleotide metabolism are mentioned. This is followed by definition of the term NAFLD, description of various stages and clinical characterization of the disease. In the final part of the thesis the results of studies concerned with the role of excessive fructose consumption in NAFLD development are summarized. Excessive consumption of fructose by healthy subjects during isocaloric diet doesn't result in hepatic fat accumulation due to effective compensatory mechanisms. However, the role of fructose in hypercaloric diet in the increase of hepatic fat content hasn't been definitely explained yet. It seems that excessive caloric intake per se is more important than the effect of fructose or its metabolites. More pronounced rise in hepatic fat content...
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Knowing of parents about the risks associated with high intake of simple sugars in preschool and early school children
Měšťanová, Michaela ; Váchová, Alena (advisor) ; Kočí, Jana (referee)
This book is about the most common risks associated with excessive sugar intake in young children. The theoretical part first discusses the chemical side of carbohydrates, their types and mode of metabolism. We will remember how carbohydrates are divided, why they play an irreplaceable role in our body, and I also mention which types of carbohydrates we should give our children daily and which, on the contrary, exceptionally. Furthermore, the most common types of sugar and sweeteners (eg honey, chicory syrup, cane sugar), which we probably know from ordinary households or advertisements, are listed in the theoretical part. Here I summarize their properties, uses and refute some myths. Then I briefly mention the history of sugar use. In the next part I mention individual diseases and complications associated with excessive sugar intake. They pay more attention to obesity, because the disease is spreading more and more in our young population and its negative effects are huge. Not only on the health side of the child and his development, but also on the psychological side, which in my opinion is very little associated with obesity. At the same time, the psyche plays a crucial role in the course and treatment of obesity. In the practical part, I devoted myself to the research of parents of children in...
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Effect of glucose on the corrosion behaviour of AZ31 magnesium alloy in saline solution
Faltýnková, Denisa ; Hasoňová, Michaela (referee) ; Doskočil, Leoš (advisor)
This bachelor thesis deals with the influence of glucose concentration on corrosion behaviour of magnesium alloy AZ31 in saline solution. The theoretical part briefly summarises the use of magnesium and its alloys in biomedical applications and offers insight into the current state of knowledge of the effect of glucose on corrosion of these materials. In the experimental part, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the electrochemical behaviour of AZ31 alloy in saline solution with varying concentrations of glucose. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterise post-corrosion surface of the alloy. The corrosion environment was analysed by measurement of conductivity, pH, inductively coupled plasma atomic emission spectroscopy (ICP-OES) and liquid chromatography with conductivity detector. Results showed that glucose, depending on concentration, impairs corrosion resistance of AZ31 alloy in 0.9% NaCl. Three organic acids were identified in the corrosion environment, of which gluconic acid is the most abundant.
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The role of mitochondrial metabolism in initiation and adaptation to hypoxic conditions.
Rohlenová, Terezie ; Novák, Petr (advisor) ; Rohlena, Jakub (referee)
We can meet pathological hypoxia in the cases of hearth attack, ischemic stroke, but also during tumor invasion, thanks to insufficient angiogenesis. The activation of HIF- 1 factor during hypoxic conditions is crucial for the cell survival. This factor modulates energetic metabolism in favor of fast progressing glycolysis (with the contribution of glutaminolysis) which provides to cell enough ATP and "building blocks", while suppressing Krebs cycle and respiration because of shortage of oxygen. The thesis studies energetic metabolism of HepG2 cells (derived from liver carcinoma) which are cultivated in the media with various energetic substrates, i. e. glucose or galactose (always together with glutamine and pyruvate) under the hypoxic conditions (5% O2). HepG2 cells use particularly oxidative metabolism for ATP and "building blocks" production under the normoxic conditions while hypoxic environment causes metabolic shift in glycemic condition. Interestingly, cells cultured in galactose (glutamine) didn't switch the energy metabolism from oxidative to aerobic glycolysis such as cells cultivated in glucose, although HIF-1 factor was stabilized. We found that enhanced activity and integrity of mitochondria, enhanced maximal capacity and reserve capacity of respiration chain correlates with...
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Study of Boron-Carbohydrate Interaction
Vejvodová, Tereza ; Jelínek, Ivan (advisor) ; Coufal, Pavel (referee)
The interaction between boron and sugars is significant for understanding the role of boron as a carrier for nucleotides and carbohydrates. Arylboronic acids also have wide application as sugars sensors because they are small and flexible molecules. Boron complexes play a key role in boron neutron capture therapy. This radiotherapy is important in the treatment of melanoma, glioblastoma multiforme and other types of cancer. Boron complexes with ascorbic acid and glucose were prepared in this thesis and then characterized by high-resolution mass spectrometry (HRMS). Synthesised complexes were studied using collision-induced dissociation (CID), which led to the clarification of their fragmentation mechanism. Key Words Boron complexes, ascorbic acid, glucose, carbohydrates, mass spectrometry, electrospray ionization, ESI-MS, collision-induced dissociation
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