Search

This paper presents a study of the characteristic effects of the physicochemical properties of microcrystalline cellulose and a series of biocarbon samples produced from this raw material through thermal conversion at temperatures ranging from 200 °C to 850 °C. Structural studies revealed that the biocarbon samples produced from cellulose had a relatively low degree of graphitization of the carbon and an isometric shape of the carbon particles. Based on thermal investigations using the differential thermal analysis/differential scanning calorimeter method, obtaining fully formed biocarbon samples from cellulose feedstock was possible at about 400 °C. The highest direct carbon solid oxide fuel cell (DC-SOFC) performance was found for biochar samples obtained via thermal treatment at 400–600 °C. The pyrolytic gases from cellulose decomposition had a considerable impact on the achieved current density and power density of the DC-SOFCs supplied by pure cellulose samples or biochars derived from cellulose feedstock at a lower temperature range of 200–400 °C. For the DC-SOFCs supplied by biochars synthesised at higher temperatures of 600–850 °C, the "shuttle delivery mechanism" had a substantial effect. The impact of the carbon oxide concentration in the anode or carbon bed was important for the performance of the DC-SOFCs. Carbon oxide oxidised at the anode to form carbon dioxide, which interacted with the carbon bed to form more carbon oxide. The application of biochar obtained from cellulose alone without an additional catalyst led to moderate electrochemical power output from the DC-SOFCs. The results show that catalysts for the reverse Boudouard reactions occurring in a biocarbon bed are critical to ensuring high performance and stable operation under electrical load, which is crucial for DC-SOFC development. [ABSTRACT FROM AUTHOR]

This study investigates the impacts of structure and composition on the optical and electronic properties of a series of pyridinium-based bismuth iodide complexes. Organic substrates with various functional groups, such as 4-aminopyridine (4-Ampy), 4-methylpyridine (4-Mepy), 4-dimethylaminopyridine (4-Dmapy), and 4-pyridinecarbonitrile (4-CNpy) with different electron-donating and electron-withdrawing groups at the para position of the pyridine ring were employed. Crystallographic analysis reveals various bismuth iodide structures, including 1D chains and discrete 0D motifs. The optical band gap of these materials, identified via diffuse reflectance spectroscopy (DRS) and verified with density functional theory (DFT) calculations, is influenced by the crystal packing and stabilising interactions. Through a comprehensive analysis, including Hirshfeld surface (HS) and void assessment, the study underscores the influence of noncovalent intermolecular interactions on crystal packing. Spectroscopic evaluations provide insights into electronic interactions, elucidating the role of electron donor and acceptor substituents within the lattice. Thermogravimetric differential thermal analysis (TG–DTA) indicates structural stability up to 250 °C. Linear sweep voltammetry (LSV) reveals significant conductivity in the range of 10–20 mS per pixel at 298.15 K. X-ray absorption spectroscopy (XAS) at the Bi L3 edge indicates a similar oxidation state and electronic environment across all samples, underscoring the role of bismuth centres surrounded by iodides. [ABSTRACT FROM AUTHOR]

In vitro cytotoxicity assessment is indispensable in developing new biodegradable implant materials. Zn, which demonstrates an ideal corrosion rate between Mg‐ and Fe‐based alloys, has been reported to have excellent in vivo biocompatibility. Therefore, modifications aimed at improving Zn's mechanical properties should not degrade its biological response. As sufficient strength, ductility and corrosion behavior required of load‐bearing implants has been obtained in plastically deformed Zn‐3Ag‐0.5Mg, the effect of simultaneous Ag and Mg additions on in vitro cytocompatibility and antibacterial properties was studied, in relation to Zn and Zn‐3Ag. Direct cell culture on samples and indirect extract‐based tests showed almost no significant differences between the tested Zn‐based materials. The diluted extracts of Zn, Zn‐3Ag, and Zn‐3Ag‐0.5Mg showed no cytotoxicity toward MG‐63 cells at a concentration of ≤12.5%. The cytotoxic effect was observed only at high Zn2+ ion concentrations and when in direct contact with metallic samples. The highest LD50 (lethal dose killing 50% of cells) of 13.4 mg/L of Zn2+ ions were determined for the Zn‐3Ag‐0.5Mg. Similar antibacterial activity against Escherichia coli and Staphylococcus aureus was observed for Zn and Zn alloys, so the effect is attributed mainly to the released Zn2+ ions exhibiting bactericidal properties. Most importantly, our experiments indicated the limitations of water‐soluble tetrazolium salt‐based cytotoxicity assays for direct tests on Zn‐based materials. The discrepancies between the WST‐8 assay and SEM observations are attributed to the interference of Zn2+ ions with tetrazolium salt, therefore favoring its transformation into formazan, giving false cell viability quantitative results. [ABSTRACT FROM AUTHOR]

The countless interpretations of The Master and Margarita emphasize the most disturbing thought for the readers. This is an amazingly simple and moving truth: from the clutches of the Soviet Empire which destroys the Master only Satan can release him. The Master's saviour is the spirit of evil. In this article I would like to show Bulgakov's rich and ambiguous topography of evil, then to expand view of the topography of good. [ABSTRACT FROM AUTHOR]