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Study of membrane properties of liposomal systems using fluorescence spectroscopy
Zbořilová, Hana ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
The presented diploma thesis is focused on the preparation, characterization and study of membrane properties of liposomal systems which were composed of the neutral phosphatidylcholine (DPPC), cholesterol, negatively charged phosphatidylglycerol (DPPG), polyethylenglycol bounded to phosphatidylethanolamine (PEG5000–PE) and polycation N,N,N-trimethylchitosan (TMC). The influence of individual components and their concentrations on the average particle size, zeta potential and changes in the outer and inner part of the bilayer was investigated. In this matter, methods of dynamic and electrophoretic light scattering and fluorescence spectroscopy with the application of laurdan and DPH probes were used. Based on the above-mentioned parameters, concentrations of components that most suitably influence properties of liposomes in terms of the intended application were selected for the definite complex. It was managed to prepare a liposomal complex stealth liposome–N,N,N-trimethylchitosan, which, due to the optimized composition, could have suitable attributes as a drug delivery system for inhalation administration of biologically active substances.
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Hyaluronan ionocomplexes for cosmetic and farmaceutical applications
Cimalová, Jana ; Obruča, Stanislav (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on the study of a system of cationic surfactant – hyaluronan. Using fluorescent spectroscopy the critical micellar concentration of Carbethopendecinium bromide (Septonex) was determined in three environments – water, 0,15 M NaCl, and buffer PBS, with three fluorescent probes – pyrene, perylene, and nile red. It was found that the physiological environments (buffer and NaCl) reduce the value of CMC about one order. During the experiments with native hyaluronan, precipitate and gel formation were observed. The following part dealt with aggregate behaviour of the new biologically acceptable amphoteric surfactant tetradecylfosfocholine (TPC) in the environment of water and NaCl according to the increasing molar molecular weight of hyaluronan. As a fluorescent probe perylene was used. These measurements showed that the molar molecular weight or a change of ionic force has no effect on the value of CMC and therefore there are no interactions with hyaluronan. The last surfactant to study was 1,2-dihexadecanoyl-3-dimetylammonium-propan (DPTAP), which is water insoluble. DPTAP is soluble in chloroform, but after evaporation of chloroform and after addition of hyaluronan, it precipitated. The results so far, have confirmed that in terms of research of aggregation by fluorescence spectroscopy the new cationic surfactants TPC and DPTAP are not suitable for complexation with hyaluronan.
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Refund Analysis VAT for Company UNIOB spol. s r.o.
Smutný, Nikola ; Mráčková, Ludmila (referee) ; Kopřiva, Jan (advisor)
The bachelor‘s thesis considers harmonization of value added tax in the European Community and third countries. The thesis analyze the real and model situation. The output is optimal refundation of VAT. The thesis is resolving specific company UNIOB L.L.C. It’s optimization whole procedure of tax subjects in the proces of refundation and payment to the other states.
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Trader’s Application for a Refund VAT from EU Countries
Moravec, Petr ; Penka, Miroslav (referee) ; Kopřiva, Jan (advisor)
The bachelor‘s thesis considers harmonization of value added tax in the European Community. It targets the refundation of VAT. The thesis analyses influence of communitary law on national law and the diferences between legislations of individual states. Issue of the thesis is describe conditions and examination of the claim to refundation. It describes whole procedure of tax subjects in the proces of refundation from the states of European Union.
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Tax Criminality in VAT
Kubíková, Jitka ; Krytinářová, Lenka (referee) ; Kopřiva, Jan (advisor)
Bachelor’s thesis is focused on the issue of tax criminality in the Czech Republic. The first part describes the theoretical background and basic concepts related to the issue. There are also analyzed existing types of legal and illegal tax evasion, critical points of origin and the level of penalties. The aim of this thesis is to compare the tax crime with any of the neighboring countries and to propose measures against tax evasion.
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Quality of hydrophobic domains in polyelectrolyte-surfactant system
Holínková, Petra ; Vala, Martin (referee) ; Mravec, Filip (advisor)
In this bachelor thesis were studied the photophysical properties of four fluorescent probes depending on the viscosity of their surroundings by the fluorescence spectroscopy. For probes DPH, DPB a perylene was determinated dependence of fluorescence anisotropy and for P3P dependence of ratio excimer/monomer on the viscosity of the sample. Anisotropy probes DPH and perylene were also used to study interaction between hyaluronan and cationic surfactant CTAB (concentration below CMC) in aqueous solution and 0,15 M NaCl. Information about forming hydrophobic domains were obtained by measurement of fluorescence intensity and anisotropy depending on the concentration of CTAB in the sample. It was found that in an aqueuos solution, after the initial addition of CTAB to hyaluronan formed small hydrophobic domains linked to chain of hyaluronan. Increasing concentration of CTAB leads to the formation of gel and phase separation. After addition of NaCl leads to reorganization of this system and probably the formation of free micelles in the solution with higher concentration of CTAB.
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VAT in Health Care and its Influence on the Health Facilities in the Czech Republic
Keclíková, Stanislava ; Kučerová, Marie (referee) ; Kopřiva, Jan (advisor)
This bachelor's thesis describes the issues and characteristics of value added tax in relation to health care, which is one of the areas that, from the perspective of tax laws, raise a number of complex issues. The theoretical part contains a description of the principle of value added tax and the characteristics of the medical system. The practical part includes the analysis of the issue of VAT of a particular state health-care organization. The final part consists of the evaluation of the present situation, a suggestion for solution and the anticipated impact of potential changes related to tax reform.
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Influence of ionic strength on the properties of ionic amphiphilic pairs
Filipová, Lenka ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
The Bachelor thesis studies catanionic vesicle systems consisting of ion pair amphiphile (IPA) and their properties in the presence of ionic strength. Ion pair amphiphile was prepared from single-chained surfactants: cationic surfactant HTMAB (hexadecyltrimethylammonium bromide) and anionic surfactant SDS (sodium lauryl sulfate). Cationic double-chained surfactant DDAC (dimethyldioctadecylammonium chloride) was added in order to stabilize the vesicle system and make it positively charged. Cholesterol was also added to further stabilize the vesicle system. The system is considered to be relatively stable when consisting of 90 % IPA and 10 % DDAC with 43 mol.% cholesterol in a membrane. The stability of the system can be disrupted by external factors such as ionic strength. The Ionic strength was induced by NaCl solutions of varying concentrations (0.0, 0.5, 1.0, 2.0, 50.0, 100.0, 150.0 and 300.0 mM). The change of properties of a vesicle system, which was induced by ionic strength, was analyzed by electrophoretic and dynamic light scattering, fluorescence anisotropy, and generalized polarization. –potential was obtained by electrophoretic light scattering analysis which determines the stability of the system. Dynamic light scattering measurement resulted in the determination of the size of vesicles. The fluidity of vesicles’ membranes was examined by fluorescence anisotropy with DPH (1,6-diphenyl-1,3,5-hexatriene) as a probe. The hydration shell of vesicles was observed by generalized polarization with Laurdan (2-(dimethylamino)-6-dodecanoylnaphthalene) as a probe. As a result, it was found out that low ionic strength (0.5 to 2.0 mM) causes a decrease in the size of vesicles and high ionic strength (50.0 to 300.0 mM) causes vesicles to grow in size. –potential showed a consistent trend for the whole concentration series – its value rapidly decreasing with increasing ionic strength. The samples with the concentrations of salt 50.0 to 300.0 mM were considered unstable according to the –potential data. Fluorescence anisotropy decreases with increasing temperature and increasing ionic strength. The value of generalized polarization decreases with increasing temperature; hence there is more solvation of a vesicle membrane. The highest value of generalized polarization was measured when the concentration of sodium chloride was relatively high (from 50.0 to 300.0 mM), as a result of which the membrane was less hydrated and therefore, more organized.
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Ekonomická činnosť spojená s koňmi z pohľadu DPH
Škovran, Patrik
Škovran, P. Business activity related to horses from the VAT perspective. Diploma thesis. Brno: Mendel University, 2023. This diploma thesis deals with equestrian facilities in relation to value added tax. The objective was to formulate recommendations for company executives and entrepreneurs who are running or plan to engage in the running of equestrian facil- ities, in terms of ensuring their economic activity in a way that is in accordance with legal and tax regulations of value added tax. The work begins with an overview of professional literature and legal enactments, in which the basic terms related to the given issue are explained and defined. Based on this part of the work, the analytical part follows, which consists of a questionnaire survey conducted among equestrian facilities, an analysis of activities connected with the value added tax of a specific equestrian facility, an interview with a tax consultant specialized in value added tax, and a summary of the issue of VAT rates and composite supplies following the judge- ments of CJEU. These parts of the work subsequently served as a starting point for formulated recommendations for companies from the given sector.
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