Publikace vydané Univerzitou Pardubice / Published by the University of Pardubice
Stálý URI pro tuto komunituhttps://hdl.handle.net/10195/37631
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Článek Otevřený přístup peer-reviewedpublished Effect of concentration of zinc-powder in epoxy-ester based anticorrosive coatings(University of Pardubice, 2023) Raycha, Yash; Kohl, Miroslav; Kalendová, Andréa; Adam, MartinThe present work is directed to study the effect of zinc powder concentration on anticorrosive efficiency of epoxy ester resin-based anticorrosive coatings. A high performance of zinc coating for metal protection is of vital importance depending on the concentration of zinc incorporated into coating formulation. Zinc pigment gives protection against corrosion by cathodic protection and barrier protection mechanism; however, it is necessary to keep adequate dosage of zinc. A lower dosage of zinc is insufficient to obtain sufficient cathodic protection while much higher concentration leads to the pores in the film which may influence corrosion. Therefore, this study was focused on the development of highly effective zinc coatings for excellent anticorrosion protection, as well as mechanical performance, when using standardized tests on corrosion, mechanical and chemical properties.Článek Otevřený přístup peer-reviewedpublished Polyfluorene derivatives as a promising candidate for coating application(University of Pardubice, 2023) Mechergui, Imen; Piana, Francesco; Kohl, Miroslav; Kalendová, Andréa; Adam, MartinThis paper is focused on the synthesis and the characterization of one of the cationic water-soluble conjugated polymers based on polyfluorene (PF) derivatives with terminal amino-groups named poly(9,9-bis(2-(N-ethan(pyrolin-1-yl))ethan)fluorene dibromide (shortly abbreviated as "para phenyl") synthesized by Suzuki-Miyaura coupling reaction and quaternized through a bromoalkylation on pyrrolidine groups, giving rise to a conjugated ammonium polyelectrolyte (P2). The structure of the obtained polyfluorene derivatives (P1 and P2) was confirmed by 1H NMR and FTIR and their photophysical, electrical, and electrochemical properties fully investigated. The results show that the new polyfluorene electrolyte could be a strong candidate as a coating material thanks to its chemical stability and high conductivity.Článek Otevřený přístup peer-reviewedpublished Study on the properties of new anti-corrosion pigments containing Mg2+ cation in epoxy ester resin-based coatings(University of Pardubice, 2023) Boštíková, Karolína; Kalendová, Andréa; Kohl, Miroslav; Adam, MartinThe aim of the work was to study the protective properties of epoxy ester coatings containing newly synthesized organic pigments based on azo compounds in dependence of their chemical composition and concentration. For applications in anti-corrosion coatings, organic pigments containing the Mg2+ cation with expected anti-corrosion properties have been newly synthesized and their effect on epoxy ester coatings' physicochemical and corrosion resistance studied. In the same effort, inorganic oxides with Mg2+ cation content based on periclase and mixed magnesium-iron oxide and an industrial standard were also tested, the effectiveness of which had already been confirmed in previous studies. The properties of the prepared paint materials and organic coatings were investigated using standardized physical-mechanical tests together with accelerated cyclic corrosion tests in simulated corrosive atmospheres and electrochemical linear polarization technique. The results obtained with the coatings based on tested pigments containing epoxy-ester resin have confirmed the corrosion-inhibiting effect of the newly synthesized pigments.Článek Otevřený přístup peer-reviewedpublished Microwave decomposition in the recycling of gadolinium from waste contrast agents(University of Pardubice, 2023) Audrlická Vavrušová, Lenka; Tykva, Marek; Krejčová, Anna; Adam, MartinUnconsumed gadolinium-based contrast agents used in magnetic resonance imaging become medical waste after application. Such a waste is a mixture of plastic, glass, and the contrast agent itself and is usually burned in a hospital incinerator. Due to this, further recyclable materials are lost, as well as gadolinium, which is a valuable industrial commodity. This work is focused on the possibilities of recycling waste containing gadolinium, when seeking optimum conditions for converting the gadolinium complex into the nitrate form applicable to further processing. The respective procedure is compared with the commonly used incineration of medical waste in terms of environmental impacts. An LCA study comparing such ecologic aspects of these two product systems was developed. The current predominance of fossil sources in the composition of the energy mix in the Czech Republic is the reason for the less favorable assessment of the newly proposed procedure.Článek Otevřený přístup peer-reviewedpublished Current trends in exosome isolation methods: A systematic review(University of Pardubice, 2023) Morávek, Ondřej; Bílková, Zuzana; Adam, MartinExosomes, extracellular vesicles crafted via a regulated process involving endocytosis, biomolecule packaging, and exocytosis, possess diverse functions. Exosomes participate in many processes crucial for the functionality of cells and tissues, e.g. in intercellular communication, immune response, programmed cell death, inflammation, and morphogen transport. Based on their multifunctional activity, the exosomes also play a significant role in many pathological conditions, such as malignancy or neurodegeneration. Nanosized exosomes carry various biomolecules as nucleic acids, proteins, lipids, metabolites. It has already been revealed that the composition of exosomes often corresponds with the (patho)physiological status of a cell, tissue, organ, and, ultimately, an organism. That is why the exosomes/oncosomes become promising structure suitable for studying the pathogenesis of the relevant disease or for the early and precise diagnosis of many serious diseases. The barrier for their wider use is the difficulty to isolate exosomes in the desired quantity and quality. To date, various isolation strategies have been proposed, spanning physico-chemical and affinity-based methods. Even the accelerated exosome isolation techniques exploiting the benefits of magnetic carriers or microfluidic platforms are still facing some limitations, and it is already clear where new trends can be expected. A concise review of strategies and technologies for exosome isolation is given here.Článek Otevřený přístup peer-reviewedpublished Phenolic content and antioxidant activity of linden syrup prepared from dried flowers by hot and cold brewing(University of Pardubice, 2023) Červenka, Libor; Muriqi, Sali; Frühbauerová, Michaela; Adam, MartinLinden flower syrup has been used as a supportive treatment for colds in folk medicine. In this study, syrup was prepared by mixing sucrose and herbal infusion made by hot (HB) and cold (CB) brewing from air-dried (AD) and freeze-dried (FD) linden flowers. The syrup was preserved by heating at 75 °C for 25 min followed by storage at 5°C for 21 d. The colour, pH, phenolic content, and antioxidant activity were determined. Hot brewing produced syrups with a significantly higher amount of phenolics, flavonoids, and antioxidant activity than cold brewing. The contents of catechin (39.59 mg/L), epicatechin (159.07 mg/L), chlorogenic acid (44.66 mg/L) and tiliroside (1.92 mg/L) contents were higher for HB-FD than those of the HB-AD samples. Regarding cold brewing, it was found to effectively extract catechin, epicatechin, and chlorogenic acid from air-dried flower samples.Článek Otevřený přístup peer-reviewedpublished Evaluation of regular and decaffeinated (un)roasted coffee beans based on antioxidant capacity and total phenolic content(University of Pardubice, 2023) Klikarová, Jitka; Řeháková, Barbora; Česlová, Lenka; Adam, MartinIn this study, the effect of coffee beans processing (decaffeination and roasting) on their antioxidant capacity and total phenolic content has been investigated. In a total of 64 regular as well as decaffeinated (un)roasted coffee samples, these characteristic parameters were determined spectrophotometrically using the DPPH free-radical method and the Folin-Ciocalteu assay. While the total phenolic content remained unchanged regardless of the processing method used, the antioxidant capacity of the samples varied depending on their treatment being affected mainly by the decaffeination procedure chosen.Článek Otevřený přístup peer-reviewedpublished Simultaneous voltammetric determination of flavouring substances in Christmas spices(University of Pardubice, 2023) Štumrová, Eliška; Švancara, Ivan; Sýs, Milan; Adam, MartinA new electroanalytical method for the simultaneous determination of flavouring substances has been developed when utilising anodic oxidation of eugenol, myristicin, and anethole in an acidic medium in combination with square-wave voltammetry and the glassy carbon electrode. Electroanalytical performance of the respective method was verified on analysis of model solutions, as well as real samples of Christmas spices. In overall, the method proposed has shown some potential for implementation into analysis of medicaments, where one can find the above-specified substances as active pharmaceutical ingredients or flavouring agents, and where only minimal matrix effect can be expected.Článek Otevřený přístup peer-reviewedpublished Catecholase biomimetic copper(II) complex immobilization via Schiff's base formation onto the cross-linked polymers prepared by drop-casting(University of Pardubice, 2022) Sýs, Milan; Bártová, Michaela; Hartmanová, Aneta; Mikysek, Tomáš; Adam, MartinIn this article, a universal protocol is introduced dealing with covalent immobilization of catecholase biomimetic copper(II) complexes with free carbonyl group onto the primary amine-based polymeric substrates (chitosan and collagen, type II) cross-linked with glutar-aldehyde; both being enabled via Schiff's base formation. As a representative of biomimetic catalysts, [Cu2Ac2O(L)ClO4] consisting of a 2,6-bis(4-methyl piperazin-1-ylmethyl)- 4-formyl-phenoxy ligand (L) was selected. The resulting functionalized polymers formed at the surface of a screen-printed carbon electrode were characterized using scanning electron microscopy with energy dispersive X-ray analysis. As a result, the procedure presented herein could find use in the development of artificial biosensors.Článek Otevřený přístup peer-reviewedpublished Moisture sorption properties of matcha tea powder as affected by high humidity storage(University of Pardubice, 2022) Červenka, Libor; Palarčík, Jiří; Zeman, Vojtěch; Muriqi, Sali; Adam, MartinThe effect of high relative humidity (RH) storage on the subsequent moisture sorption of matcha tea powder was examined. The sample of interest was stored above silicagel (control), at 52.9 and 75.3 % RH for two months at 25 °C. Moisture adsorption and desorption experiments were performed using a dynamic vapor system, and the sigmoid-shaped (type II) isotherms obtained with the aid of multi-Freundlich equation. Hysteresis loop disappeared for powder samples previously exposed to high humidity environment. According to Caurie and multi-Freundlich equations, higher critical values of aw, monolayer content, number of monolayers, and surface area of adsorption were observed for the samples stored under high RH. The change in the particle size distribution was also discussed.