Antioxidants and stabilizers

Summary The efficiency of polyolefine melt stabilizer 2, 2-thiobis-(4,6-di-tert.butylphenol) (I) as a hydroperoxide decomposing antioxidant was studied under model conditions.tert.Butylhydroperoxide was used to simulate the reaction with polypropylene hydroperoxide. The reaction was performed at 85°C in chlorobenzene solution. Decomposition of tert.butylhydroperoxide by I and formation of the sulphoxide II and the sulphone III from sulphide I were followed quantitatively. Formation of small amounts of effective peroxidolytic species from II or III, responsible for acceleration of hydroperoxide decomposition was considered.     

Correction to: Optimal face templates: the next step in surveillance face recognition

Pattern Analysis and Applications - In the original publication of the article, the below-mentioned acknowledgement was not included and the author would like to add it.     

Grain Coarsening of Columnar Iron Polycrystals by Repetitive Cold Work and Annealing

Metallurgical and Materials Transactions A - Experimental studies on single crystals of pure metals are essential for understanding the mechanisms governing their plastic deformation as well as for...     

Structure and Properties of the Gypsum Mortar with Silica Sand Under Temperature Load

International Journal of Thermophysics - The electrospray (ES) cooling technique, which is a combination of spray cooling and high-voltage electrostatic technology, has attracted considerable...     

Analytical capabilities of inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) for multi-element analysis of food and beverages

Analytical capabilities of ICP-oa-TOF-MS for rapid, simultaneous and reliable determination of more than 50 major, trace and ultra-trace elements in different food and beverages samples (milk and dairy based products, cereals, meat, offal, sugar and sugar products, potatoes, fats, baby food samples, fruit juices, alcoholic beverages), following microwave closed vessel digestion of samples, were described. Under optimum instrumental conditions, and by using Rh as an internal standard and an external calibration method, ICP-oa-TOF-MS enables an accurate analysis, taking about one minute per a sample for all elements and isotopes of interest even for some elements such Zn, Ni, Cu, As or Co whose assay is more difficult when using conventional quadrupole instruments. In order to verify the accuracy and precision of the proposed method, 8 commercially available reference materials representing 3 major groups of food (milk and dairy based products, meat, cereals) were analysed, yielding results in agreement with certified values and the precision bellow 15%. In addition, accuracy was confirmed by spiked analytical recoveries study and accurate isotopic ratio determinations with the precision typically better than 5% with 5 s data acquisition period, also for other elements of interest whose content was not certified and different sample matrices. Limits of detection (3σ) have varied from 0.04 ng g⁻¹ for Th to 1630 ng g⁻¹ for Ca.     

Selectively Halogenated Flavonolignans—Preparation and Antibacterial Activity

A library of previously unknown halogenated derivatives of flavonolignans (silybins A and B, 2,3-dehydrosilybin, silychristin A, and 2,3-dehydrosilychristin A) was prepared. The effect of halogenation on the biological activity of flavonolignans was investigated. Halogenated derivatives had a significant effect on bacteria. All prepared derivatives inhibited the AI-2 type of bacterial communication (quorum sensing) at concentrations below 10 µM. All prepared compounds also inhibited the adhesion of bacteria (Staphyloccocus aureus and Pseudomonas aeruginosa) to the surface, preventing biofilm formation. These two effects indicate that the halogenated derivatives are promising antibacterial agents. Moreover, these derivatives acted synergistically with antibiotics and reduced the viability of antibiotic-resistant S. aureus. Some flavonolignans were able to reverse the resistant phenotype to a sensitive one, implying that they modulate antibiotic resistance.     

Microstructures and mechanical properties of Mg–Zn–Y alloy consolidated from gas-atomized powders using high-pressure torsion

In this paper, rapid solidified Mg₉₅Zn_4.3Y_0.7 (at.%) alloy powders produced by an inert gas atomizer were consolidated using a severe plastic deformation technique of high pressure torsion (HPT) at room temperature and 373 K. The behavior of powder consolidation, matrix microstructural evolution, and mechanical properties of the powders and compacts were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness, and tensile testing. As the HPT processing temperature increases, the powders are more plastically deformed due to decreased deformation resistance, grain boundaries are more in equilibrium, powder bonding is enhanced due to increased interparticle diffusion, hence, tensile ductility and strength increases. On the other hand, hardness decreases with the increased processing temperature, due to less dislocation density.