Ceramides: focus on obesity

It is generally known that obesity increases the risk of developing cardiovascular disease. A pathological increase in the mass of adipose tissue leads to a violation of the control of lipid accumulation at the molecular level, abnormal lipid metabolism with the formation of metabolites, which are critical for the development of these pathologies against the background of obesity. Ceramides are one of these metabolites. Ceramides perform many physiological functions, but under pathological conditions they induce insulin resistance, uncouple cellular respiration and phosphorylation, activate cell apoptosis, and play an important role in the induction of adipose tissue dysfunction. Altering ceramide biosynthesis through dysregulation of key enzymes leads to the formation and accumulation of ceramides, which block insulin signaling and induce adipose tissue inflammation.This review highlights the metabolism of ceramides, the reasons for their ectopic deposition in tissues in obesity, as well as potential intracellular signaling pathways that modulate ceramide activity

Electrochemical study of semiconductor properties for bismuth silicate-based photocatalysts obtained via hydro-/solvothermal approach

Three bismuth silicate-based photocatalysts (composites of Bi2SiO5 and Bi12SiO20) prepared via the hydro-/solvothermal approach were studied using electrochemical methods. The characteristic parameters of semiconductors, such as flat band potential, donor density, and mobility of their charge carriers, were obtained and compared with the materials’ photocatalytic activity. An attempt was made to study the effect of solution components on the semiconductor/liquid interface (SLI). In particular, the Mott–Schottky characterization was made in a common model electrolyte (Na2SO4) and with the addition of glycerol as a model organic compound for photocatalysis. Thus, a medium close to those in photocatalytic experiments was simulated, at least within the limits allowed by electrochemical measurements. Zeta-potential measurements and electrochemical impedance spectroscopy were used to reveal the processes taking place at the SLI. It was found that the medium in which measurements were carried out dramatically impacted the results. The flat band potential values (Efb) obtained via the Mott–Schottky technique were shown to differ significantly depending on the solution used in the experiment, which is explained by different processes taking place at the SLI. A strong influence of specific adsorption of commonly used sulfate ions and neutral molecules on the measured values of Efb was shown

Photoactive bismuth silicate catalysts: Role of preparation method

The published papers highlight the photocatalytic properties of bismuth silicates, especially Bi2SiO5. Meanwhile, there is limited information on the formation of bismuth silicates that hinders the controlled synthesis of pure phases of bismuth silicates or composites on the basis thereof. The study is focused on the influence of preparation conditions on the interaction of initial reagents at each stage of synthesis taking into account the roles of solvent (water or ethylene glycol (EG)), precipitation agent, Si-containing component as well as the calcination procedure. The key role in these transformations is played by the stable Bi(III)–EG complex that participates in the Bi3+ reduction to metallic state under solvothermal conditions. The phase formation process is accomplished during the thermal treatment of the samples synthesized from EG solution. A four-phased composite material demonstrates the highest photocatalytic performance in photodegradation of Rhodamine B and phenol solutions via selective deethylation and mineralization processes, respectively