Odborné časopisy / Journals
Stálý URI pro tuto komunituhttps://hdl.handle.net/10195/38093
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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 Unveiling ceramide synthase 2 (CerS2): From characteristics and isolation to enzyme activity assays(University of Pardubice, 2023) Shabani, Egzontina; Bílková, Zuzana; Adam, MartinCeramide synthase 2 (CerS2) is an essential enzyme in the metabolic pathway of sphingolipids, a class of membrane lipids that act crucial roles in various cellular functions [1]. Among the six mammalian CerS enzymes, CerS2 stands out for its omnipresence and abundant expression in various mammalian tissues and organs. CerS2 mRNA and protein expression levels are particularly prominent in the kidney, liver, lung, intestine, and other essential tissues [1–3]. This widespread distribution underscores CerS2's significance as a critical contributor to basal cellular sphingolipid metabolism. The enzyme's substrate specificity for specific acyl-CoAs, such as C20:0, C22:0, C24:0, C24:1, and C26:0, further accentuates its role in generating distinct ceramide species. CerS2's presence has been identified in the endoplasmic reticulum (ER), where it catalyzes the synthesis of ceramides by combining fatty-acyl chains with dihydrosphingosine. Analysis of CerS2 expression and activity involves a combination of techniques, when the real-time PCR measures mRNA levels, thus providing insights into the transcriptional regulation of CerS2. Western blotting is used to determine the protein abundance of CerS2 on its overall protein levels. In this review, we offer a thorough analysis of CerS2, encompassing its distinctive characteristics, biological relevance, isolation methods, quantification at both the mRNA and protein levels, as well as an assessment of its enzymatic activity via appropriate assays.Článek Otevřený přístup peer-reviewedpublished Comparison of culture methods for the detection of Salmonella in wastewater(University of Pardubice, 2023) Roulová, Nikola; Moťková, Petra; Brožková, Iveta; Pejchalová, Marcela; Adam, MartinThe goal of this work was to find an effective culture method for the detection of Salmonella in wastewater, which would consider both the recommendation of ISO standard 19250 and the specific nature of the wastewater matrix. Three culture methods that differed primarily from the use of the non-selective pre-enrichment step and the processing of wastewater samples prior o the selective enrichment step and further divided into ten protocols depending on the selective enrichment conditions, have been compared with respect to the detection of Salmonella in naturally polluted municipal and hospital wastewater samples. Two selective enrichment broths (MKTTn and RVS) at two incubation temperatures (37 °C and 41.5 °C) plus four media (XLD, DC, BG, and Rambach) were used in this study. The results have shown that the selective enrichment step is the key factor in the culture protocol for detecting Salmonella in wastewater. Such conditions for enrichment (that is, the broth and incubation temperature used) had a major effect on the multiplication of Salmonella to detectable levels, suppressing competing bacteria, and on the efficiency of solid media, thus significantly influencing the isolation rates of Salmonella from wastewater. MKTTn broth performed better for Salmonella isolation from wastewater than that for RVS broth. Incubation at 41.5°C significantly increased the level of Salmonella detection by both selective enrichment broths. XLD and DC agar were the most efficient solid media in this study. The combination of MKTTn broth incubated at 41.5 °C and XLD agar constituted the best approach for isolating Salmonella from wastewater.Článek Otevřený přístup peer-reviewedpublished The parameters of Mg/Fe(Al) layered double hydroxides/mixed oxides related to the synthesis(University of Pardubice, 2023) Frolich, Karel; Tišler, Zdeněk; Mück, Jáchym; Skuhrovcová, Lenka; Adam, MartinThe Mg-Fe layered double hydroxides (LDH) are becoming to be a group of promising materials with a lot of applications depending on their properties. These are influenced by the methods of synthesis, where it is not clearly presented which synthesis is suitable for materials with desired parameters. The aim of this work was to synthesize MgFe LDH according to standard recipes used for common MgAl LDH, when showing similarities and differences in-between the samples of Mg-Al and Mg-Fe LDH and derived mixed oxides (MO). Extensive experimental characterization of material structure and surface has been performed. Originally, statistical analysis of the characterization data revealed that LDH from particular synthesis were grouped together, showing statistical similarities. The structure properties of samples from particular synthesis were similar to both series of Mg/Al and Mg/Fe and also for the molar metal ratios 3/1 and 4/1. Oxides were completely rehydrated to the LDH form only for the co-precipitation method. The cell parameters in LDH and rehydrated forms mutually strongly correlated indicating the same layer properties of parent LDH and their rehydrated forms. The oxides that originated from the hydrothermal method had significantly higher densities of basic centres and population of strong O2− basic structures due to the abundance of surface defects and other phases. Oxides prepared by the sol-gel method showed somewhat higher density of the acid centres.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.