Determining pesticide contamination in honey by LC-ESI-MS/MS – Comparison of pesticide recoveries of two liquid–liquid extraction based approaches

Honey, a valuable food product, may be contaminated by xenobiotics during its production and/or harvest. The determination of trace levels of contaminants in a complex matrix like honey still presents a challenge to analytical chemists. The aim of this work was to assess and compare the extraction efficiencies of 30 pesticide residues (acaricides, insecticides, herbicides, fungicides), belonging to over 15 different chemical classes. Two common extraction approaches were applied – the increasingly popular QuEChERS method and extraction on a diatomaceous earth support. Both are used for pesticide determinations in fruits and vegetables, and with some adjustments they can be used for honey samples. In order to assess whether the differences in recoveries between the two investigated methods were statistically significant, the F-Snedecor and T-test were employed. The recoveries ranged from 34 to 96%, and in the case of 4 pesticides the differences in the values were statistically significant. Both methods showed good linearity (R² > 0.991), and the extraction efficiencies enabled method quantification limits well below EU-recommended Maximum Residue Levels to be achieved for the investigated pesticides.     

Optimization of Cellular Automata Model for the Heating of Dual-Phase Steel by Genetic Algorithm and Genetic Programming

This study considers a common metallurgical problem associated with the phase transformation of steel during heating where austenite grain tends to grow in size with time and results in poor mechanical properties in the final stages. This investigation was performed using a Cellular Automata model for dual-phase steel developed in house. Data-driven metamodels for a biobjective optimization problem involving minimizing average austenite grain size along with the maximizing of time of heating were constructed using Evolutionary Neural Network (EvoNN) and Biobjective Genetic Programming (BioGP). The input variables selected for this task were (i) heating rate, (ii) pearlite percentage, (iii) nucleation density of austenite, and (iv) the finish temperature of austenite formation. The analyses of the results led to the fact that heating rate is the most influencing factor and it needs to be large during transformation to obtain a refined microstructure. The comparison of Pareto front between EvoNN and BioGP reveals a better performance of the latter. Limited experimental confirmation was also carried out.     

Tailoring magnetic anisotropy gradients by ion bombardment for domain wall positioning in magnetic multilayers with perpendicular anisotropy

Graded anisotropy magnetic materials possess a coercive field changing laterally with position. A simple fabrication procedure to produce such an anisotropy gradient in a polycrystalline Au/Co layer system without lateral thickness variation and with perpendicular magnetic anisotropy, prototypical for a large variety of thin film systems, is shown. The procedure uses light-ion bombardment without the use of a mask. Magnetization reversal in this polycrystalline layer system takes place by unidirectional movement of a single domain wall only in regions with larger anisotropies and anisotropy gradients. In this anisotropy/anisotropy gradient regime, the domain wall is oriented perpendicular to the coercive field gradient, and it can be positioned along the gradient by an appropriate magnetic field pulse. For smaller anisotropies/anisotropy gradients, the natural anisotropy fluctuations of the polycrystalline layer system induce magnetization reversal dominated by domain nucleation.

PACS

75.30.Gw; 75.70.Cn; 75.60.Ch     

DomESA: a novel approach for extending domain-oriented lexical relatedness calculations with domain-specific semantics

Being able to correctly model semantic relatedness between texts, and consequently the concepts represented by these texts, has become an important part of many intelligent information retrieval and knowledge processing systems. The need for such systems is especially evident within the biomedical domain, where the sheer amount of scientific publishing contributes to an information overflow. In this paper we present a novel method to approximate semantic relatedness in domain-focused settings. The approach is an extension to a well-known ESA (Explicit Semantic Analysis) method. Our extension successfully leverages the semantics of a domain-specific document corpus. We present the evaluation of the proposed method on a set of reference datasets, that are a de facto reference standard for the task of approximating biomedical semantic relatedness. The proposed method is evaluated in comparison with other state-of-the-art methods, as well as the baselines established with the original ESA method. The results of the experiments suggest that the proposed method combines the semantics of a general and domain-specific corpora to provide significant improvements over the original method.     

Possibilities of Increase of Adhesion of the Cubic Boron Nitride Coatings by Applying an Interfacial Layers

ON the base of literature data[1,9,12-14,16,18]itcan be found,that except of hard layers(for examplenitrides and carbides of transient metals),increasinginterest in superhard materials like boron nitride anddiamond for wear-resistant coatings deposited oncutting tool edges is still growing.Diamond having agreat affinity to iron reacts easily with Fe.It is a seriouslimitation when using diamond for steel machining.Forthis reason tools with diamond coating are used formachining non-ferrous allo…     

Bioactive layers based on black glasses on titanium substrates

Black glasses are amorphous materials based on silicon oxycarbide. The use of precursors in the form of ladder‐like silsesquioxanes enables the control of the amount of carbon ions in the glass network by adjusting ratios of T to D structural units in precursors. In this study, four different sols precursors of four different layers of black glasses on titanium substrates were prepared. The materials were analyzed with the use of various spectroscopic and microscopic methods. Formation of continuous and hermetic layers resistant to corrosion was proven. The black glasses layers were examined as materials for biomedical applications. Therefore, preliminary tests of their bioactivity and biocompatibility were performed. The best results were obtained for the material of lower contribution of carbon ions.     

Optimal design of EMAT transmitters

A three-part finite element model is developed that characterizes the ultrasonic pulse produced by an electromagnetic acoustic transducer (EMAT). The model represents several significant improvements over previously published works, as follows: (a) spatial inhomogeneities in the magnetic flux density are calculated and then incorporated in the determination of body forces, (b) an improved model of the electromagnetic induction phenomenon is formulated, allowing a more accurate evaluation of the ultrasonic pulse launched by an EMAT transmitter and (c) results from the model are compared directly with experimental measurements, yielding discrepancies of the order of 15% in the amplitude of the ultrasonic pulse. The new model is used to optimize the design of the EMAT system. In particular, a parametric study was conducted on the effects of varying an EMAT's magnet-to-coil width ratio. For the EMAT configuration considered, significant improvements can be achieved in the ultrasonic beam amplitude and profile by increasing the ratio to about 1.2; further increases in magnet dimensions yield only marginal improvements in the ultrasonic beam, at the cost of excessive EMAT size.