Voltammetric Determination of Hydroxymethylfurfural in Foodstuffs

V první části teoretické práce je popsáno rozdělení medu dle vyhlášky s následným podrobnějším popisem jednotlivých druhů medu. Krátce jsou zmíněny i medy méně známé. Další část teoretické práce je věnována látkám, které jsou obsaženy v medu, především však hydroxymethylfurfuralu, který pokud je v medu obsažen ve vyšší koncentraci poukazuje na nesprávné skladování, zahřívání nebo falšování medu a produktů z něj. V závěru teoretické části jsou popsány metody, které jsou nejčastěji používané pro stanovení hydroxymethylfurfuralu. Část této kapitoly je věnována voltametrickým metodám včetně používaných elektrod,a to především na bázi uhlíku. V experimentální části je popsána příprava roztoků, uhlíkových pastových elektrod a použité metody stanovení hydroxymethylfurfuralu, včetně instrumentace. V části výsledky a diskuze je popsána volba základního elektrolytu a optimalizace podmínek pro stanovení hydroxymethylfurfuralu. Tato část také popisuje spolehlivost metody na modelových a reálných vzorcích.The first part of theoretical part of this thesis describes in detail honey and its types according to regulation. Less known types of honey are briefly mentioned. Next part deals with substances contained in honey, especially hydroxymethylfurfural which enormously high concentration in honey points to bad storage, heating or forgery of honey or its products. Last part of theoretical part describes methods often used for hydroxymethylfurfural determination voltammetry and commonly used electrodes are mentioned. Experimental part describes preparation of liquids, carbon paste electrodes and methods used for hydroxymethlyfurfural determination and their instrumentation. Part Results and Discussion describe choice of supporting electrolyte and method conditions optimization. It also describes reliability on model and real samples.Fakulta chemicko-technologick

Mycobacterium leprae - diseases, diagnosis and history

Bakalářská práce se v úvodních kapitolách zabývá charakteristikou Mycobacterium leprae a historií výskytu onemocnění. Dále se soustředí na diagnostiku původce onemocnění, zejména pomocí molekulárně biologických testů, jejichž přesnost a včasnost jsou základními faktory pro eliminaci lepry. Následuje popis různých forem onemocnění od lepromatózního k tuberkuloidnímu pólu dle Ridley-Jopling stupnice pro klasifikaci lepry. Kromě pěti základních forem lepry je věnována pozornost i vzhledově podobným kožním onemocněním. Poté, co je diagnostikována určitá forma lepry, je možno zahájit efektivní farmakologickou léčbu pomocí kombinací různých léků. Těmto možnostem léčby se věnuje závěrečná část práce.In the early chapters the essay is addressing the characteristics of the Mycobacterium leprae and the history of the incidence of the disease. This is followed by the diagnostics of the cause of the disease; especially the molecular biology tests that are accurate and time effective and that is the main factor of the elimination of leprosy. The following is a description of various forms of the disease from lepromatous to tuberculoid as per the Ridley-Jopling scale. The attention, except for the five basic forms of leprosy, is also given to similar skin diseases. When the particular form of leprosy is diagnosed, the effective pharmacologic cure can begin using a multi-drug therapy. The last chapter of the essay is devoted to the multi-drug therapy.Katedra biologických a biochemických věd1. Prezentace výsledků bakalářské práce. 2. Diskuze k posudku vedoucího bakalářské práce. 3. Studentka zodpověděla všechny dotazy a připomínky k BP

Electrochemical Determination of Hydroxymethylfurfural

Tento příspěvek prezentuje elektrochemické stanovení hydroxymethylfurfuralu (HMF) s využitím elektrody ze skelného uhlíku.This contribution presents an electrochemical behaviour of hydroxymethylfurfural (HMF) at glassy carbon electrode and offers a method for its determination. HMF undergoes the reduction showing one irreversible process involving two electrons. The influence of various electrolytes as well as pH dependence is described herein. The problems connected with stability of the signal are also discussed. The optimized method was used for determination of HMF in honey and in mead

Study of Natural and Artificial Aging on AlSi9Cu3 Alloy at Different Ratios of Returnable Material in the Batch

Aluminum alloys currently play an important role in the production of castings in various industries, where important requirements include low component weight, reduction of the environmental impact and, above all, reduction of production costs of castings. One way to achieve these goals is to use recycled aluminum alloys. The effect of natural and artificial aging of AlSi9Cu3 alloy with different ratios of returnable material in the batch was evaluated by a combination of optical, scanning, transmission microscope and mechanical tests. An increase in the returnable material in the batch above 70% resulted in failure to achieve the minimum value required by the standard for tensile strength and ductility. The application of artificial aging had a positive effect on the microstructure and thus on the mechanical properties of experimental alloys. By analyzing the results from TEM, it can be stated that in the given cases there is a reduced efficiency of θ’-Al2Cu precipitate formation with an increase of the returnable material in the batch and in comparison with artificial aging, which is manifested by low mechanical properties

Microstructural Characteristics of Al-Ti-B Inoculation Wires and Their Addition to the AlSi7Mg0.3 Alloy

Commercially supplied inoculation wires have a guaranteed chemical composition but not the size and distribution of individual phases, which are very important for nucleation. Therefore, two commercial alloys used for the inoculation of Al-Si alloys (AlTi3B1 and AlTi5B1) are investigated in this paper. The emphasis is placed on their structural analysis and the size and distribution of individual intermetallic phases. Furthermore, the grain refinement effect will be tested by adding these alloys to the AlSi7Mg0.3 alloy and testing the optimal amount of added inoculation wires. The results showed that the size and distribution of the individual phases in AlTi3B1 and AlTi5B1 meet the requirements for the successful inoculation of aluminum alloys, the intermetallic phases based on the TiAl3 phase are fine enough, and there is no agglomeration that would reduce the number of nuclei. This assumption was confirmed by adding these inoculants to the AlSi7Mg0.3 alloy, and it was found that the most ideal amount of inoculants added is 0.01 wt % when the structure was refined by approximately 32%

European vegetation archive (EVA). An integrated database of European vegetation plots

The European Vegetation Archive (EVA) is a centralized database of European vegetation plots developed by the IAVS Working Group European Vegetation Survey. It has been in development since 2012 and first made available for use in research projects in 2014. It stores copies of national and regional vegetation- plot databases on a single software platform. Data storage in EVA does not affect on-going independent development of the contributing databases, which remain the property of the data contributors. EVA uses a prototype of the database management software TURBOVEG 3 developed for joint management of multiple databases that use different species lists. This is facilitated by the SynBioSys Taxon Database, a system of taxon names and concepts used in the individual European databases and their corresponding names on a unified list of European flora. TURBOVEG 3 also includes procedures for handling data requests, selections and provisions according to the approved EVA Data Property and Governance Rules. By 30 June 2015, 61 databases from all European regions have joined EVA, contributing in total 1 027 376 vegetation plots, 82% of them with geographic coordinates, from 57 countries. EVA provides a unique data source for large-scale analyses of European vegetation diversity both for fundamental research and nature conservation applications. Updated information on EVA is available online at http://euroveg.org/eva-database