University of Pardubice (Czech: Univerzita Pardubice or UPA) is a university in Pardubice, the Czech Republic. In 2021 it had nearly 8,000 students. It is the only university in Pardubice Region.
The minimum ignition energy (MIE) is a parameter used to assess electrostatic hazards in industrial dust dispersions. This study evaluates the application of the FEST algorithm, a procedure originally developed for the characterisation of energetic materials, to lycopodium dust in a Hartmann tube. By constructing sensitivity curves based on the log-normal cumulative distribution, the FEST method, which applies the delivered energy concept according to ASTM E2019, is compared with the EN 13821 standard evaluation using the nominal energy concept, and testing according to ASTM E2019, using the delivered energy concept, is also discussed. Although the higher number of trials required for the FEST method can limit its routine industrial use, the approach complements standard testing by providing a probabilistic context to discrete energy values, making risk assessments more reliable. Due to the large number of trials required to achieve acceptable accuracy, the FEST method is recommended for use at the dust concentration at which the standard method achieved the lowest ignition energy.
In this work, we developed biodegradable cellulose acetate (CA) fibers infiltrated with ZnO nanocrystals for the Acne vulgaris (AV) treatment. The antibacterial effect (through Zn2+ release) was activated upon oxygen plasma treatment. CA fibers (fiber diameter ≈ 2 µm) were produced via centrifugal spinning, followed by ZnO infiltration (up to 8 wt% of Zn content) using Vapor Phase Infiltration (VPI) with varying deposition cycles. As CA fibers are naturally hydrophobic, oxygen plasma treatment was applied to turn them hydrophilic and to improve skin wetting. The combination of these steps is presented for the first time. Plasma treatment introduced oxygen-containing functional groups on the CA surface, significantly improving wettability. Scanning electron microscopy analyses of treated fibers showed no morphological damage. Detailed characterization (using X-ray photoelectron spectroscopy, Raman spectroscopy, energy dispersive X-ray fluorescence, X-ray diffraction, tranmission electron microscopy) focused on fibers with 32 and 128 VPI cycles, revealed that plasma partially oxidized and etched the surface, affecting the ZnO distribution. Plasma-modified fibers, unlike untreated ones, exhibited antibacterial activity against AV-causing bacteria (Cutibacterium acnes and Staphylococcus epidermidis), creating significant inhibition zones (up to 5 mm), demonstrating their potential as promising therapeutic modality. Overall, plasma treatment enabled effective surface functionalization, producing antibacterial fibers with enhanced surface properties suitable for application in AV management.
Glutathione is a critical intracellular antioxidant that neutralizes reactive oxygen species and participates in detoxification. The ratio of its two forms, the reduced and disulfide, serves as an indicator of cellular oxidative stress associated with both acute and chronic disorders. Monitoring intracellular levels of glutathione and thiols involved in its metabolism is important for the proper characterization of cellular injury. However, current analytical methods often require tedious chemical derivatization, lack adequate retention and selectivity for highly polar analytes, or suffer from severe matrix effects when profiling the broader metabolic pathway. In this study, a robust hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method was developed and optimized for the comprehensive analysis of glutathione metabolism in cell samples without chemical derivatization. The method focused on the label-free quantitation of 21 key metabolites, encompassing intact glutathione and other thiols, their oxidized forms, precursor amino acids, and related sulfur-containing compounds. Chromatographic performance was systematically investigated in HILIC mode using sulfobetaine zwitterionic stationary phase. The final method employed 0.05
Anion exchange has been recognized as one of the most effective approaches for mediating the spontaneous formation of mixed-halide perovskite nanocrystals (MHPs) with tunable optical properties and color quality. However, the difference in the diffusion capability of halides, specifically between bromide and iodide species, into MHPs makes these materials prone to halide deficiency, which deteriorates their structural integrity and stability. In this work, we studied the surface passivation and composition engineering by introducing a dinuclear calcium-iodide scorpionate complex (CaISC) dispersed into different organic solvents such as chloroform, dichloromethane, 1,2-dichloroethane, and acetonitrile, which favor or hinder the I-for-Br exchange process between this ligand and native CsPbBr3 perovskite nanocrystals (PNCs). By analyzing the CaISC content and the nature of the solvent, we are able to efficiently promote halide exchange, also generating an intermediate mononuclear Ca2+ complex, favoring Ca2+ doping and the diffusion of a high density of iodide species for triggering Pb2+ and halide defect compensation. From this strategy, suitable CaISC-capped CsPbBr3-xIx PNCs active layers were prepared for the fabrication of efficient down-light converters, with operational stability up to 480 h. This contribution offers an alternative for the processing of stable multicolor PNCs with facile modulation of their photophysical properties, making them adequate for the fabrication of future LED technologies.
Neutral Te(II) species 2-(tBuNCH)C6H4TeCl ([I]Cl) as well as tellurenyl Te(II)+ cations [2-(tBuNCH)C6H4Te][X] (X = OTf or SbF6), i.e., [I][OTf] and [I][SbF 6 ], exhibit a wide range of reactivity toward various ortho-quinones. While the reaction of ortho-chloranil leads to the oxidation of Te(II) into Te(IV), 3,5-di-tert-butyl-ortho-benzoquinone leads only to partial oxidation due to an ongoing dynamic reversible reaction, being the first example of a chemically reversible two electron Te(II)/Te(IV) redox couple. By contrast, 9,10-phenanthrenequinone as a very weak oxidant shows no reaction; however, the most Lewis acidic [I][SbF 6 ] produces a corresponding Lewis adduct interacting by both electrostatic and weak chalcogen bond interactions. The diverse reactivity scope is further complemented by DFT computed thermochemistry data. Furthermore, [I][OTf] is successfully utilized for the catalytic transfer of silanes (Et3SiH, Ph3SiH, Ph2SiH2, and (EtO)3SiH) to ortho-quinones via redox single or double Si-H bond activation, yielding silylated catechols, monomeric cyclic catecholatosilanes, or bis(catecholato)silanes. Surprisingly, in the absence of the catalyst [I][OTf], the reactivity spans from no reaction to the formation of hexachloro-dibenzo[1,4]dioxine-2,3-dione. The latter product is an entirely different substance class compared to the one formed during the catalyzed reaction.
