|
|
Determination of sodium and potassium in honey samples by atomic absorption spectrometry
Venclová, Veronika ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
This bachelor thesis was focused on the determination of sodium and potassium in honey samples by atomic absorption spectrometry with a flame atomization technique. An acetylene-air flame was used. Prior to the analysis of the honey samples, the optimal working parameters of the used method were found. The optimized parameters were: the height of the beam above the burner, the flow rate of acetylene, and the burner's horizontal position. Under the optimal conditions, the basic characteristics of the determination of sodium and potassium were studied. Sodium and potassium concentrations in the honey samples were determined under optimal conditions. A total number of 27 honey samples were analyzed. The sodium content ranged from 0.880 to 25.3 mg/kg. The potassium content was in the range of 223 - 2750 mg/kg. In the end, the measured concentrations of honey samples originating from the Czech Republic were compared with the foreign studies. Keywords Potassium, sodium, honey, atomic absorption spectrometry, flame spectrometry
|
|
| |
|
| |
|
|
Advanced carbon structures as a material for Na-ion batteries
Bečan, Jan ; Čech, Ondřej (referee) ; Kazda, Tomáš (advisor)
This diploma thesis deals with the description of individual types of batteries. The first part is focused to primary and secondary batteries, materials for their positive and negative electrodes with a focus on lithium-ion batteries and their changes over time. The next section focuses on a more detailed description of sodium-ion batteries, used electrode materials and to their problems. Practical part is focesed to preparing of electrode materials and to completing of measuring electrochemical cell and to discribing of measuring methodes and to evaluation of measured data.
|
|
|
Simulation of processes in cellular membranes
Melcr, Josef ; Jungwirth, Pavel (advisor)
Simulation of processes in cellular membranes Abstract Many important processes in cells involve ions, e.g., fusion of synaptic vesi- cles with neuronal cell membranes is controlled by a divalent cation Ca2+ ; and the exchange of Na+ and K+ drives the the fast electrical signal transmis- sion in neurons. We have investigated model phospholipid membranes and their interactions with these biologically relevant ions. Using state-of-the-art molecular dynamics simulations, we accurately quantified their respective affinites towards neutral and negatively charged phospholipid bilayers. In order to achieve that, we developed a new model of phospholipids termed ECC-lipids, which accounts for the electronic polarization via the electronic continuum correction implemented as charge rescaling. Our simulations with this new force field reach for the first time a quantitative agreement with the experimental lipid electrometer concept for POPC as well as for POPS with all the studied cations. We have also examined the effects of transmembrane voltage on phospholipid bilayers. The electric field induced by the voltage exists exclusively in the hydrophobic region of the membrane, where it has an almost constant strength. This field affects the structure of nearby water molecules highlighting its importance in electroporation. 1
|
|
|
Použití soli a její vliv na jakostní parametry masných výrobků
Musilová, Martina
Bachelor´s thesis summarizes the use of salt and its influence on the quality parameters of meat products. The theoretical part contains basic information about the distribution of meat products according to public notice or about a technology. Another part of the theory is focused primarily on the use of salt in meat products, not only in production but also in relation to human health. The thesis has a detailed look at the root causes of using salting mixtures in the tech-nology, mainly influencing on the appearance and overall quality of meat products and the distribution of these mixtures. An important part of the work is also content of sodi-um, as part of table salt, which is a raw material widely used in production technology of meat products, and its impact on consumer health. The last part of the theory are ways to replace table salt in production technology of meat products and methods for determining salt content.
|
|
|
Determination of selected elements in potato tubers by atomic absorption spectrometry
Fořtová, Lucie ; Hraníček, Jakub (advisor) ; Kozlík, Petr (referee)
The main aim of this bachelor thesis was a determination of the elements K, Mg, Ca, Na, Zn and Fe in the potato tubers and in their boiled solution using the method of flame atomic absorption spectrometry. The chosen samples were late consumer potato tubers of Granada cultivar (boiling type B). It was necessary to optimize working conditions before the sample analysis. The optimal flow rate of acetylene ranged from 2.0 to 2.5 l/min using the flame acetylene-air. The flame acetylene-nitrous oxide was used only for calcium with flow rate 6.0 l/min. The optimal height of a beam above the burner edge was measured in interval 5 to 7 pieces of defined scale mentioned in a manual for spectrometer GBC 933 AA. Using the optimal conditions, the basic characteristics for individual methods of determination were characterized (LOD, LOQ, LDR, sensitivity, repeatability). Limits of quantification were following: 78, 31, 7.0, 8.0, 190 and 71 μg/l for K, Na, Mg, Ca, Fe and Zn, respectively. The optimal conditions were used for the determination of the selected elements in samples. The solutions were prepared from diversely processed potato tubers (whole, whole without skin, chopped without skin, skin) by boiling into deionized water. After the samples had cooled down, the concentrated nitric acid was added...
|
|
|
The influence of salt on health and salt consumption in the Czech Republic
Malinová, Pavlína ; Dostálová, Jana (advisor) ; Chrpová, Diana (referee)
The salt intake in the Czech Republic is almost three times higher than the daily recommended amount. The excessive consumption of salt has impacts on health and wellbeing in many ways. It causes or affects the course of several illnesses, including arterial hypertension, osteoporosis, asthma bronchiale, kidney diseases, gastric cancer, obesity or oedema. The theoretical part of this dissertation describes the mechanisms by which the salt acts on the body and the relationships between the diseases listed above and the salt intake. The aim of this paper is to explore the eating habits around salt intake amongst the healthcare professionals. Furthermore, it investigates the understanding and interest in this matter amongst this group of people. Anonymised questionnaires were the chosen research method for this paper. The questionnaire, comprising of 17 questions, was sent to 12 different instituts and clinics at a hospital in Prague. In total, 174 healthcare professionals took part in this research. The results showed that the participants took interest in ingredients and nutritional value of their food, however, only a minority paid attention to the salt content. One of the most consumed types of food with a high content of salt are: white cheese, blue cheese, salami and smoked meats. Though savoury...
|
|
|
Negative Electrode for Sodium-ion batteries
Šimek, Antonín ; Jaššo, Kamil (referee) ; Libich, Jiří (advisor)
This bachelor thesis contains general introduction to the issue of batteries, their basic principles and distribution. It is mainly focused on the research of electrode materials for negative electrodes of sodium-ion batteries, which do not use lithium for their function. Thesis is also focused on lithium-ion batteries, because their development is closely linked to sodium-ion batteries. The practical part mainly contains the synthesis and characteristics of sodium metatitanate, which is used as active material in negative electrode mass.
|
|
|
Simulation of processes in cellular membranes
Melcr, Josef ; Jungwirth, Pavel (advisor)
Simulation of processes in cellular membranes Abstract Many important processes in cells involve ions, e.g., fusion of synaptic vesi- cles with neuronal cell membranes is controlled by a divalent cation Ca2+ ; and the exchange of Na+ and K+ drives the the fast electrical signal transmis- sion in neurons. We have investigated model phospholipid membranes and their interactions with these biologically relevant ions. Using state-of-the-art molecular dynamics simulations, we accurately quantified their respective affinites towards neutral and negatively charged phospholipid bilayers. In order to achieve that, we developed a new model of phospholipids termed ECC-lipids, which accounts for the electronic polarization via the electronic continuum correction implemented as charge rescaling. Our simulations with this new force field reach for the first time a quantitative agreement with the experimental lipid electrometer concept for POPC as well as for POPS with all the studied cations. We have also examined the effects of transmembrane voltage on phospholipid bilayers. The electric field induced by the voltage exists exclusively in the hydrophobic region of the membrane, where it has an almost constant strength. This field affects the structure of nearby water molecules highlighting its importance in electroporation. 1
|
guest ::
