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The formation of biogenic amines in flesh of selected fish species
MATĚJKOVÁ, Kateřina
The thesis deals with the use and effectiveness of some less common methods of conservation of fish meat. The formation of biogenic amines in meat is observed in connection with the non-traditional preservative methods. Amines can serve as indicators of protein degradation. The quality of fish was considered in connection with the increasing content of selected biogenic amines (putrescine, cadaverine, spermidine, spermine, 2-fenylathylamine, histamine, tyramine and tryptamine). Ultra performance liquid chromatography (UPLC) was used as the method for determination of biogenic amines. Amines were derivatized by dansylchloride before their UPLC separation. The fish flesh was vacuum-packed. Samples were stored for several weeks in a thermostat at the selected storage temperature after the application of selected preservative technique. Beta-irradiation and high hydrostatic pressure were used for the preservation of fish flesh. Control samples were not exposed to the â-irradiation and high pressure. The organoleptic properties were studied for all samples (smell/odor, insight and shape). Beta-irradiation was applied to fish meat of common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss). Both these species of freshwater fish are economically significant. Carp and trout are the species being mostly consumed in the Czech Republic. Fish meat is considered to be provided the flesh is fresh. A testing series of samples was created with common carp to determine the appropriate dose of â-irradiation. The maximum permissible dose of irradiation for fish meat is 3 kGy. Fish samples were exposed this dose in the first experiment. The dose of irradiation was reduced in following experiments based on the experience from the initial experiment. The doses of 0.25, 0.5, 0.75, 1.0 and 2.0 kGy were applied to rainbow trout. The value of 0.75 kGy of â-irradiation or higher (1.0, 2.0 and 3.0 kGy) prolonged the shelf life of fish meat, which was stored for three months (98 days). Prolonging of the shelf life of fish meat to approximately 98 days at 3.5 °C is redundant from technical point of view. For that reason lower doses 0.25, 0.5 and 0.75 kGy were tested in more detail in the repeated experiment with carp meat. Lower doses of â-irradiation are considered to be more acceptable and-at the same time-sufficiently effective for delaying the beginning of degradation processes. 6 High hydrostatic pressure was applied to meat of common carp (Cyprinus carpio), rainbow trout (Oncorhynchus mykiss) and pike (Exos lucius). Pike is another very popular kind of freshwater fish. Pike flesh is very tasty, but in spite of this, pike is not so much popular among consumers compared to carp and trout. The cause is its high price. Samples of pike were stored at standard temperature 3.5 °C and also at higher temperature 12 °C (unlike experiments with â-irradiation). Lower temperature of storage (3.5 °C) followed the conditions of storing of fish meat in industrial refrigeration facilities and households. The high pressure might not be sufficient for preservation at higher storage temperatures. This assumption was based on available information. Samples were treated by high pressure and stored at both 3.5 °C and 12 °C to verify this assumption. Higher temperature simulated either failure of refrigeration equipment or unsuitable store temperature of meat. In all species selected freshwater fish two levels of high pressure were applied ? 300 and 500 MPa. Both levels had significantly reduced the formation of biogenic amines, especially in samples stored at 3.5 °C. At this temperature, the effect of 300 and 500 MPa delayed start of degradation processes in fish meat by 3?4 weeks. At 12 °C and 500 MPa, high pressure extended the sustainability of meat by no more than one week. 500 MPa is effective treatment at the lower temperature of 3.5 °C. High pressure is not reliable preservative techniques at higher temperature.
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Titaniun Dioxide - Phosphonate Assemblies as Medical Nanoprobes
Řehoř, Ivan ; Lukeš, Ivan (advisor) ; Lang, Kamil (referee) ; Peters, Joop (referee)
Titanium Dioxide - Phosphonate Assemblies as Medical Nanoprobes Ivan Řehoř PhD. Thesis Abstract: Multimodal imaging-therapeutic nanoprobe TiO2@RhdGd was prepared and successfully used for in- vitro and in-vivo cell tracking as well as for killing of cancer cells in-vitro. TiO2 nanoparticles, 12 nm in diameter, were used as a core for phosphonic acid modified functionalities, responsible for contrast in MRI and optical imaging. The phosphonic acid derivatives, used for surface modification, allows for grafting extraordinarily high loads of irreversibly adsorbed molecules of both types in one step. The prepared probe shows very high 1 H r1 relaxivity value as well as relaxivity density value, both crucial parameters for its use in MRI. The presence of fluorescent dye in its structure allows for its visualization by means of fluorescence microscopy. The applicability of the probe was studied, using three living systems - mesenchymal stem cells, cancer HeLa cells and T-lymphocytes. The probe did not exhibit toxicity in any of these systems and its long time storage in a lysosomal compartment was confirmed. Labeled cells were successfully visualized in-vitro by means of fluorescence microscopy and MRI. Consequent visualization of labeled cells in-vivo by means of fluorescence microscopy was also achieved....
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Mesial temporal epilepsy: comparison of morphological changes after different neurosurgery approaches with clinical seizure outcome
Malíková, Hana ; Vymazal, Josef (advisor) ; Kršek, Pavel (referee) ; Hájek, Milan (referee)
Background: Mesial temporal lobe epilepsy (MTLE) is the most surgically amenable epilepsy diagnosis and the results of epilepsy surgery are clearly superior to prolonged medical therapy. Stereotactic radiofrequency amygdalohippocampectomy (SAHE) is an alternative therapy of MTLE to the open neurosurgery approaches. In our hospital SAHE has been used since 2004. We produced lesions from the occipital access with a single trajectory in the long axis of amygdalohippocampal complex (AHK) using the probe with a flexible active tip. The aim of this study was to correlate the morphological changes after different neurosurgical approaches including volume reduction of the target structures / the hippocampus, the amygdala, entorhinal (EC) and perirhinal (PRC) cortices/ with the clinical seizure outcome. Methods: We included 26 consecutive patients, who underwent SAHE using Leksell stereotactic system and 10 patients treated by microsurgical amygdalohippocampectomy (AHE). MR volumetry of hippocampus, amygdale, EC and PRC was performed 1 year after the procedure. The clinical outcome was assessed 2 years after the procedure according to Engel's Classification. Results: No serious adverse events occurred after both procedures. One year after SAHE, the hippocampal volume decreased by 55.5 18.0% (p<10-4 ), the...
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The Effect of Temperature Annealing on Structure-Property Relationship of Oriented Polypropylene
Sadílek, Jiří ; Jančář, Josef (referee) ; Kohout,, Jan (referee) ; Hell,, Jaroslav (referee) ; Kučera, Jaroslav (advisor)
The aim of this work is to study the effect of thermal history to structure and properties not only of oriented polypropylene monofilaments with different orientation but of course of isotropic non-oriented polypropylene. Term thermal history includes thermal regimes from alpha relaxation temperature (T?) to melting temperature (Tm). This work consists of three parts. The changes of dynamic mechanical properties, strength, deformation and tensile modulus of polypropylene samples according to annealing temperature (Ta) are described in the first part of this work. In the second part, the changes of crystal phase are observed. Preferentially, calorimetric behaviour (DSC), changes of crystal dimensions and orientation function of crystal phase (X-ray) are observed. Measured values from the first and the second part of this work were used for calculation of total orientation function of PP samples. Rheological measurements are shown in the third part of this thesis. Rheological measurements consist of short isothermal creep, shrinkage of free tapes and static deformation at higher temperatures. Measured rheological values were performed using rheological models. Using these models characteristics of entropic spring, instantaneous elasticity and viscosity and tendency to get to state of ease were calculated.
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Radical Reactions of the Decomposition of N-H, O-H and O-O Bonds Initiated by Homogeneous and Heterogeneous Redox Agents
Majzlík, Petr ; Mazúr, Milan (referee) ; Stopka, Pavel (referee) ; Omelka, Ladislav (advisor)
The Ph.D. thesis was focused on EPR study of redox reactions of selected types of phenols, secondary amines and diperoxy coumpounds. Within the study some redox agents were employed in nonpolar, in some special cases also in polar solvents. EPR spectra of generated radical products were interpreted using spectral simulation. Study of radical reactions under participation of phenols was preferentially concentrated on the behavior of para methyl substituted phenols, where the instability of this substituent in relation to the applied redox agents was evaluated. The tendency towards the abstraction of hydrogen from methyl group, representing the paralell mechanism to the hydrogen abstaction from phenolic OH group was proved. The generated benzyl radicals were undirectly detected in the form of adducts with aromatic nitroso compounds. These adducts undergo the consecutive transformations, leading to the formation of new types of phenoxy radicals. The study of the decomposition of NH bonds was performed with substituted N,N´-paraphenylenediamines, 1-anilino-1-phenylpentane-3-ones and amino substituted 1,3-dimethyluracils. By the oxidation with 3-chloroperbenzoic acid the corresponding nitroxyl radicals were prepared. In the case of 1-anilino-1-phenylpentane-3-ones the aminyl radicals were prepared by the oxidation with PbO2, which existence was evidenced by spin trapping method with nitrosobenzene. In the framework of the investigation of the decomposition of -O-O- bonds the oxygen centred radicals, generated from peroxidic compounds of Luperox type using selected redox agents were detected by spin trapping method. The analysis of EPR spectra documented that primary alkoxyl radicals undergo the consecutive fragmentation, which leads in the presence of oxygen to the formation of secondary alkoxyl radicals. The generation of oxygen centred radicals during the decomposition was indirectly proved in the presence of model phenolic compounds, where due to the abstraction of hydrogen from phenolic OH group the phenoxyl radicals are formed.
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Temperature and Time Influence on Crystalline and Amorphous Phase Content in Polypropylene
Vilč, Ladislav ; Petrůj, Jaroslav (referee) ; Čermák,, Roman (referee) ; Kratochvíla, Jan (advisor)
is is a study of the relationship between structure, mechanical properties and relaxing behavior of the polypropylene. The structure was evaluated by the quantity the solid phase content (SPC). This was defined as mathematical result of free induction decay (FID) signal from pulsed 1H-NMR. The solid phase content is a quite new structural parameter representing the quantity for description of semi-crystalline polymers. Whereas pulsed 1H-NMR is non-destructive, accurate and repeatable, it becomes a unique tool for a description of mechanical, structural, physical-mechanical changes of polypropylene within the time and temperature. Particularly, this method registers the small changes in the time-dependant shipments during secondary crystallization with small structure changes.
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Biologically active metabolites of plants.7.Alkaloids from Corydalis yanhusuo and their biological activity.
Koci, Buleza ; Cahlíková, Lucie (advisor) ; Siatka, Tomáš (referee)
Bulëza Koci: Biological Activity of Plant Metabolites 7. Alkaloids from Corydalis yanhusuo W.T. Wang and their inhibitory activity on acetylcholinesterase. In the process of screening for plants containing alkaloids potentially inhibiting human erythrocytic AChE and human BuChE, Corydalis yanhusuo was studied. 10.8 kg of dry tuber was percolated with 120 liters of 95% ethanol. From the primary extract, extracts with individual types of alkaloids were prepared. In this diploma thesis only one extract was processed (extract type A-ether, pH 9.7). Alkaloids from this extract were separated into bases whose chlorides were either soluble or insoluble in chloroform. From each of the above mentioned fractions phenolic and non-phenolic alkaloids were obtained. Alkaloids were separated from a fraction of alkaloids, whose chlorides are soluble in CHCl3, non-phenolic (A- non-phenolic Cl- S/CHCl3). From this mixture tetrahydropalmatine was isolated by the use of column chromatography on alumina and preparative TLC on silica gel. This compound was preliminary identified according to data of MS spectra, NMR spectra and optical rotation and by comparison with literature data . The biological activity of tetrahydropalmatine on human AChE and BuChE was found to be: IC50 876 ± 15.3 μM for HuAChE and IC50 > 1000 μM...
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Plasticizers of the branched polyesters
Matoušková, Martina ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
1 Abstract This thesis deals with the plasticizers of the oligoesters carriers of drugs. The theoretical part introduces the basic information about the properties of plasticizers, their classification and the mechanism of the effect, and provides a summary of the plasticizers for biodegradable polymers. Within the experimental part, weight loss of plasticizers during the preparing matrices by melting at 80ř C and maximum of absorption of plasticizers were observed. The elution of methyl salicylate from oligoesters carriers 0,5D, 1D a 2D was studied. Significant weight loss was determined only at ethyl pyruvate; the rest of the tested plasticizers shows the loss up to 5 %. No significant differences were found during the elution of methyl salicylate affected by the type of carrier or concentration of plasticizers. Methyl salicylate eluted by 1st order kinetics during the whole degradation time of the carriers. A disturbing effect of the methyl salicylate in dissolving medium on determination of the fluconazole was confirmed but it had no influence on the determination of the acyclovir. Key words: branched polyesters, plasticizers, drug release
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Hyperfine interactions in maghemite and magnetite particles
Křišťan, Petr ; Štěpánková, Helena (advisor) ; Procházka, Ivan (referee)
Thesis is aimed at studying of magnetic iron oxide particles of submicron and nanoscale dimensions by means of nuclear magnetic resonance (NMR). 57 Fe NMR inves- tigations were carried out in composite bentonite/maghemite with respect to tempera- ture of calcination (Tcalc) during the sample preparation and in magnetite submicron powders with respect to various range of the particles size. One of the main findings is that increasing Tcalc improves resolution in the NMR spectra, which is most likely connected with higher degree of atomic ordering in the spinel structure. Evaluating the integral intensities of NMR spectra allowed us to determine the relative content of maghemite phase in particular samples of the series: the content rapidly grows for Tcalc up to ∼420 deg. An approach to distinguish signal from tetrahedral and octahedral irons was developed and tested on pure maghemite sample. Analysis based on vacancy- distribution models was performed in the spinel structure and the results were compared to the experiment. 57 Fe NMR spectra in submicron magnetite samples were found to differ markedly from spectrum of a single crystal. It was concluded that the investigated powders possess high amount of defects in the crystal structure or contain additional phase (probably closely related to the maghemite phase).
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