Tape-Casting Performance of Ethanol Slurries for the Processing of Textured PMN–PT Ceramics from Nanocrystalline Powder

The rheological behavior and tape-casting performance of ethanol-based Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (PMN–PT) slurries is studied. A nanocrystalline powder obtained by mechanochemical activation was used. Suspensions were prepared up to solid contents of 32 vol%, significantly higher than those usually reported for nonaqueous systems. The feasibility of replacing toxic solvents commonly used for tape casting of functional ferroelectric materials, often toluene, with ethanol is demonstrated. The density, phases and microstructure of the green tapes and sintered ceramics are presented. Cube-shaped templates were successfully aligned during the tape casting for the processing of 〈001〉-textured PMN–PT ceramics by templated grain growth. An effect of the lamination of tape stacks on the template orientation is described.     

Characterization of the Amorphous Phase and the Nanosized Crystallites in High-Energy-Milled Lead–Magnesium–Niobate Powder

We have studied the formation of lead–magnesium–niobate Pb(Mg_1/3Nb_2/3)O₃ perovskite powder produced by high-energy milling of the constituent oxides. By applying a low ball-impact energy and a low ball-impact frequency we were able to identify the reaction sequences. The crystal structure and the amount of crystalline and amorphous phases in the powder were determined using a Rietveld refinement. The morphology, structure and chemical composition of the powder were investigated by transmission electron microscopy. The surface composition, possible contamination and the chemical states of the elements were analyzed by X-ray photoelectron spectroscopy. In the early stage of milling the constituent oxides comminute, refine to nanosize dimensions and become amorphous. In the second step the Pb(Mg_1/3Nb_2/3)O₃ nucleates from the amorphous regions where the stoichiometry corresponds to the perovskite. The perovskite phase nucleates and subsequently grows over the course of the milling. Simultaneously, the pyrochlore phase nucleates from the Pb- and Nb-rich regions; however, its nucleation and recrystallization stop after a certain milling time. The powder mixture consists of nanosized Pb(Mg_1/3Nb_2/3)O₃ particles and an amorphous phase when milled for 94 h. No traces of contamination from the milling media were detected.     

Influence of natural antioxidants on the formation of trans‐fatty‐acid isomers during heat treatment of sunflower oil

The intake of foods containing trans fatty acids (TFAs) can have deleterious effects on human health, mainly on the cardiovascular system. Thus, it is important to consider the processes that form TFAs in foods, and the alternatives to minimise their formation. The influence of two added natural antioxidants on TFA formation during heat treatment (120 h at 180°C) of sunflower vegetable oil were examined: rosemary extract (Rosmarinus officinalis L.) (1 g per kg oil) and lutein (0.1 g per kg oil). Changes in FA composition were determined using Ag‐ion SPE and gas–liquid chromatography, with total polar compounds determined using dielectric constant measurements and the index of atherogenicity was calculated. Total TFAs with ≥1 trans double bond increased from 0.91 to 1.71% in control samples; this increase was significantly less with both rosemary extract (1.55%) and lutein (1.43%) additions. Among the individual TFAs, significant increases were seen for C18:1,t‐9, C18:2,t‐9,t‐12 and C18:2,c‐9,t‐12/9‐t,12‐c. Polar compounds also increased, with the highest concentrations in control samples, and significantly less with both rosemary extract and lutein additions. According to results of our study, we can summarize that addition of lutein have greater effect on reduction of TFA formation than rosemary extract. Practical applications: Antioxidants, particularly from plants, are widely used in the food industry. They can provide benefits in food preparation, including improving colour, odour and stability, acting as acid regulators and natural preservatives. They have also become accepted by customers and consumers, and so indirectly they have had effects on consumer perception. Addition of natural antioxidants such as rosemary extract is usually limited by the sensory characteristics of the food, with one study showing that addition of rosemary extract at 1–3 g per kg vegetable oil is recommended. The effects of antioxidants on the formation of TFAs in vegetable oils has not been well studied in the literature. Among the already known benefits, the use of such antioxidants as functional ingredients in lipid technologies might reduce the formation of TFAs during thermal treatment.     

Trickle-Bed Oxidation Reactors

Abstract

For reactions necesitating a solid catalyst and which invoive both reisuvely volatile and nonvclarile reactants, three-phase reactirs are required. Equipment used to achieve intimate contacting of the three phases has been procominantly in the form of slurry reactors, analogous to the stirred-tank homogenous system, or fixed-bed reactors in which the two fluid phases flow through a stationary bed of catalyst particles. Trickle-bed reactors are a type ofthe second classification in which both gas and liquid flow downward through the catalyst bed. Such systems avoid the disadvantage of separating small catalyst particles from the fluid product streams associated with slurry reactors, and also avoid the limitation of flow rates uncountered with upflow or countercurrent flow through fixed beds.     

Influence of carbon black distribution on performance of oxide cathodes for Li ion batteries

The influence of carbon black content and carbon black distribution on performance of oxide-based cathodes, such as LiCoO₂ and LiMn₂O₄, is investigated. The electronic conductivity of oxide material/carbon black composites is compared with electrochemical characteristics of the same composites. Uniformity of carbon black distribution in cathode composites is achieved using novel coating technology in cathode preparation. In this technology, the active particles are first pretreated in a gelatin solution. The adsorbed gelatin then controls the deposition of carbon black so that carbon black particles are uniformly distributed in the final composite. The influence of various parameters, such as pH of gelatin, amount of gelatin and concentration of carbon black on the uniformity of carbon black distribution is investigated. It is shown that the conventional technology of cathode preparation yields quite non-uniform distribution of carbon black in cathode material. At the end, we demonstrate that uniformity of carbon black distribution has a crucial impact on reversible capacity, especially at high current densities.     

Selective Monovalent Galectin-8 Ligands Based on 3-Lactoylgalactoside

Galectin-8 has gained attention as a potential new pharmacological target for the treatment of various diseases, including cancer, inflammation, and disorders associated with bone mass reduction. To that end, new molecular probes are needed in order to better understand its role and its functions. Herein we aimed to improve the affinity and target selectivity of a recently published galectin-8 ligand, 3-O-[1-carboxyethyl]-β-d -galactopyranoside, by introducing modifications at positions 1 and 3 of the galactose. Affinity data measured by fluorescence polarization show that the most potent compound reached a K_D of 12 μM. Furthermore, reasonable selectivity versus other galectins was achieved, making the highlighted compound a promising lead for the development of new selective and potent ligands for galectin-8 as molecular probes to examine the protein's role in cell-based and in vivo studies.     

Design,Synthesis, in vitro and in silico Characterization of 2-Quinolone-L-alaninate-1,2,3-triazoles as Antimicrobial Agents

Due to the ever-increasing antimicrobial resistance there is an urgent need to continuously design and develop novel antimicrobial agents. Inspired by the broad antibacterial activities of various heterocyclic compounds such as 2-quinolone derivatives, we designed and synthesized new methyl-(2-oxo-1,2-dihydroquinolin-4-yl)-L-alaninate-1,2,3-triazole derivatives via 1,3-dipolar cycloaddition reaction of 1-propargyl-2-quinolone-L-alaninate with appropriate azide groups. The synthesized compounds were obtained in good yield ranging from 75 to 80 %. The chemical structures of these novel hybrid molecules were determined by spectroscopic methods and the antimicrobial activity of the compounds was investigated against both bacterial and fungal strains. The tested compounds showed significant antimicrobial activity and weak to moderate antifungal activity. Despite the evident similarity of the quinolone moiety of our compounds with fluoroquinolones, our compounds do not function by inhibiting DNA gyrase. Computational characterization of the compounds shows that they have attractive physicochemical and pharmacokinetic properties and could serve as templates for developing potential antimicrobial agents for clinical use.     

The General Explanation Method with NMR Spectroscopy Enables the Identification of Metabolite Profiles Specific for Normal and Tumor Cell Lines

Machine learning models in metabolomics, despite their great prediction accuracy, are still not widely adopted owing to the lack of an efficient explanation for their predictions. In this study, we propose the use of the general explanation method to explain the predictions of a machine learning model to gain detailed insight into metabolic differences between biological systems. The method was tested on a dataset of ¹H NMR spectra acquired on normal lung and mesothelial cell lines and their tumor counterparts. Initially, the random forests and artificial neural network models were applied to the dataset, and excellent prediction accuracy was achieved. The predictions of the models were explained with the general explanation method, which enabled identification of discriminating metabolic concentration differences between individual cell lines and enabled the construction of their specific metabolic concentration profiles. This intuitive and robust method holds great promise for in‐depth understanding of the mechanisms that underline phenotypes as well as for biomarker discovery in complex diseases.     

The Effect of Surface Roughness on the Corrosion Properties of Type AISI 304 Stainless Steel in Diluted NaCl and Urban Rain Solution

Due to their good corrosion resistance, favorable mechanical properties, and reasonable price regarding their excellent properties, austenitic stainless steels have, over recent decades, become one of the alloys that are increasingly used in civil engineering and building, as well as for specific architectural purposes. Architects often design stainless steel exterior elements with higher surface roughnesses, which are not resistant to corrosion processes. The aim of this work was to investigate the influence of different types of surface finishes to stainless steel of quality AISI 304 on the corrosion properties of this steel. In order to achieve this goal, electrochemical tests were performed on different surface finishes in two different environments: in an NaCl aqueous solution, and in simulated urban rain which contained no chlorides. In addition to the electrochemical methods used, surface roughness was also measured, and XPS surface analyses were performed. The results of the investigation showed that surface roughness affects the growth of the passive layer in urban rain significantly; however, the growth of such a film is retarded in the case of the NaCl aqueous solution. Based on the results of the performed analyses, it was found that, in the NaCl solution, the pitting potential depended strongly upon the surface roughness and the surface finish, but this was not true for the samples tested in urban rain.