Pokročilé polymerní materiály a kompozit
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- ItemAssessing Lettuce Exposure to a Multi-Pharmaceutical Mixture in Soil: Insights from LC-ESI-TQ Analysis and the Impact of Biochar on Pharmaceutical Bioavailability(AMER CHEMICAL SOC, 2024-09-04) Fučík, Jan; Jašek, Vojtěch; Hamplová, Marie; Navrkalová, Jitka; Zlámalová Gargošová, Helena; Mravcová, LudmilaAgricultural practices introduce pharmaceutical (PhAC) residues into the terrestrial environment, potentially endangering agricultural crops and human health. This study aimed to evaluate various aspects related to the presence of pharmaceuticals in the lettuce-soil system, including bioconcentration factors (BCFs), translocation factors (TFs), ecotoxicological effects, the influence of biochar on the PhAC bioavailability, persistence in soil, and associated environmental and health risks. Lettuce (Lactuca sativa L.) was exposed to a mixture of 25 PhACs in two scenarios: initially contaminated soil (ranging from 0 to 10,000 ng center dot g(-1)) and soil irrigated with contaminated water (ranging from 0 to 1000 mu g center dot L-1) over a 28-day period. The findings revealed a diverse range of BCFs (0.068-3.7) and TFs (0.032-0.58), indicating the uptake and translocation potential of pharmaceuticals by lettuce. Significant ecotoxicological effects on L. sativa, including weight change and increased mortality, were observed (p < 0.05). Interestingly, biochar did not significantly affect PhAC uptake by L. sativa (p > 0.05), while it significantly influenced the soil degradation kinetics of 12 PhACs (p < 0.05). Additionally, the estimated daily intake of PhACs through the consumption of L. sativa suggested negligible health risks, although concerns arose regarding the potential health risks if other vegetable sources were similarly contaminated with trace residues. Furthermore, this study evaluated the environmental risk associated with the emergence of antimicrobial resistance (AMR) in soil, as medium to high. In conclusion, these findings highlight the multifaceted challenges posed by pharmaceutical contamination in agricultural environments and emphasize the importance of proactive measures to mitigate the associated risks to both environmental and human health.
- ItemGraphene quantum dots-From spectroscopic performance to 3D printing applications and interaction studies with normal and cancer cells(Elsevier, 2024-05-27) Krok-Janiszewska, Dominika; Wielgus, Weronika; Środa, Patrycja; Tyszka-Czochara, Małgorzata; Lepcio, Petr; Kasprzyk, Wiktor; Ortyl, JoannaIn this study, different types of graphene quantum dots (GQDs) are investigated to understand their spectroscopic properties. Morphological and size analyses were performed. The mechanism of action of radical photopolymerization was evaluated. The obtained materials proved to be useful for developing efficient photoinitiating systems for 3D printing applications. In addition, the cytotoxicity of the GQDs was studied, and their effects on living cells were investigated. We demonstrated that GQDs can not only act as efficient photoinitiators but also as constituents of hydrogels that express very low toxicity and may interact with cells. The latter makes it possible to study them in the future as useful modern biosensors.
- ItemAnatase and rutile nanoparticles in photopolymer 3D-printed nanocomposites: Band gap-controlled electron interactions in free-radical and cationic photocuring(Elsevier, 2024-07-01) Korčušková, Martina; Svatík, Juraj; Tomal, Wiktoria; Šikyňová, Aneta; Vishakha, Vishakha; Petko, Filip; Galek, Mariusz; Stalmach, Paweł; Ortyl, Joanna; Lepcio, PetrThe preparation of functional photopolymer nanocomposites is affected by both the physical and chemical interactions of nanoparticles (NPs) and polymer resin. Some NPs, such as semiconducting metal oxides, may contribute by their photocatalytic behavior and electron transfer, influencing the kinetics of the photopolymerization reaction. This study has investigated the complex effect of titanium dioxide (TiO 2 ) NPs in anatase and rutile form on the conversion, kinetics, and printability of free -radical and cationic photopolymerization resin. Two different polymorphs of TiO 2 NPs ensured identical chemical properties, but different physical effects related to their varying band gap energies and electron transfer efficiency. These parameters were found to be crucial for influencing the photopolymerization kinetics. While rutile showed a more pronounced enhancement of the free -radical photopolymerization ' s conversion and kinetics, cationic photopolymerization was favourably affected only by anatase NPs due to the photosensitization effect. These findings are critical in understanding and designing functional nanocomposite materials processed by vat photopolymerization 3D printing that could find use in optical, medical, or environmental applications.
- ItemBiaxial porosity gradient and cell size adjustment improve energy absorption in rigid and flexible 3D-printed reentrant honeycomb auxetic structures(Elsevier, 2024-06-01) Štaffová, Martina; Ondreáš, František; Žídek, Jan; Jančář, Josef; Lepcio, PetrThis paper compares different uniaxial and biaxial graded designs of auxetic reentrant honeycomb structures to enhance their mechanical properties, especially the specific energy absorption under compressive load. The lattice structures were 3D printed using the vat photopolymerization masked-stereolithography technique from two different materials - tough (OR) and flexible (FR). The results were evaluated from a material and structural point of view, investigating the effect of porosity, cell number, size, graded design, and fracture mode. The universally best energy-absorbing performance was found in a biaxially graded structure with a center-wise location of the highest local porosity. Depending on the used resin, its energy absorption capacity was up to 2-3 times enhanced compared to a reference uniform-porosity auxetic design. The presented data constitutes a fundamental understanding of auxetic structures and identifies practical approaches for tuning the auxetic structures' performance regarding their mechanical response. Finally, this study demonstrates the potential of shape versatility offered by 3D printing and other additive manufacturing techniques.
- ItemMaximizing the electrochemical performance of supercapacitor electrodes from plastic waste(Elsevier, 2023-08-07) Dědek, Ivan; Bartusek, Stanislav; Dvořáček, Josef Jan; Nečas, Jan; Petruš, Josef; Jakubec, Petr; Kupka, Vojtěch; Otyepka, MichalThe management of the increasing volume of plastic waste has become a key challenge for society. A promising strategy now consists in the transformation of plastic waste into high-value materials that can be utilized in energy storage devices such as batteries and supercapacitors. In this study, we demonstrate a two-step procedure, involving pyrolysis, followed by chemical activation that will convert common plastic waste into activated carbons (ACs). This technique makes ACs suitable for supercapacitor electrode materials. Further, the electrochemical performance of ACs is outstanding in terms of capacitance, energy density, and cycling stability. Besides the well-established parameters, including a specific surface area and micropore volume, we found that other critical factors such as polymer glass transition temperature, polymer-activating agent miscibility, activating agent (K2CO3):AC ratio, and AC water dispersion stability also play a crucial role in determining the supercapacitors performance. Controlling these parameters, we obtained ACs as supercapacitor electrodes from a range of plastic waste materials with a competitive electrochemical performance. Specifically, the ACs exhibited a specific capacitance of 220 F g1 (at a current density of 1 A g1), energy and power densities of 61.1 Wh kg1 and 36.9 kW kg1, respectively, and excellent cycling stability (95 % retention after 30,000 cycles). Our findings provide a pathway towards transforming plastic waste into valuable electrode materials for supercapacitors.