Influence of temperature on the properties of Mn coatings electrodeposited from the electrolyte containing Te(VI) additive

The influence of the bath temperature on composition, current efficiency, structure, morphology, internal stresses and microhardness of Mn coatings obtained from manganese-ammonium sulphate electrolyte with 2.20 mM of Te(VI) additive at the current density of 15 A dm^?2 was investigated. It has been found that with rising of the bath temperature from 20 to 80 °C the current efficiency increases from 37 to 71 %, the total concentration tellurium in the deposits increases from 0.9 to 1.6 wt% and the average size of crystallites of the coatings declines approx. from 24 to 15 nm. The structure of Mn coatings changes from the mixture of α-Mn and β-Mn phases at the lower temperatures to α-Mn phase at higher temperatures. Large tensile stresses (from 76 to 106 MPa) were determined for the Mn coatings with the thickness of 1.5–2.0 μm obtained at the initial stage of the deposition process.     

Predicting body fat percentage based on gender,age and BMI by using artificial neural networks

In the human body, the relation between fat and fat-free mass (muscles, bones etc.) is necessary for the diagnosis of obesity and prediction of its comorbidities. Numerous formulas, such as Deurenberg et al., Gallagher et al., Jackson and Pollock, Jackson et al. etc., are available to predict body fat percentage (BF%) from gender (GEN), age (AGE) and body mass index (BMI). These formulas are all fairly similar and widely applicable, since they provide an easy, low-cost and non-invasive prediction of BF%. This paper presents a program solution for predicting BF% based on artificial neural network (ANN). ANN training, validation and testing are done by randomly divided dataset that includes 2755 subjects: 1332 women (GEN = 0) and 1423 men (GEN = 1), with AGE from 18 to 88 y and BMI from 16.60 to 64.60 kg/m². BF% was estimated by using Tanita bioelectrical impedance measurements (Tanita Corporation, Tokyo, Japan). ANN inputs are: GEN, AGE and BMI, and output is BF%. The predictive accuracy of our solution is 80.43%. The main goal of this paper is to promote a new approach to predicting BF% that has same complexity and costs but higher predictive accuracy than above-mentioned formulas.     

The influence of distribution and deposit of conductive coating on shielding effectiveness of textiles

This study presents the investigation of electrically conductive fabrics with low resistivity, coated with formulation containing the conjugated polymer system – poly(3,4-ethylenedioxythiophene)-polystyrene sulphonate (PEDOT-PSS). The samples of fabrics were coated with PEDOT-PSS, using a screen printing method, by different patterns or coating their surface fully with different coating deposit. Methods for measurement of electrostatic properties, reflection and transmission as well as the assessment of electromagnetic radiation (EMR) shielding effectiveness were used for the characterization of electrical properties of developed samples. EMR shielding properties were investigated within 2–12 GHz frequency bands. The highest attenuation of the electromagnetic energy among tested fabrics was obtained on the fabrics fully coated with paste and it depended on deposit considerably. The influence of distribution and deposit of conductive coating on shielding effectiveness of textiles were determined. Correlation between shielding effectiveness and electrostatic properties of developed coated fabrics was also discussed. Electrical properties of samples coated with formulation containing PEDOT-PSS were compared with these of fabrics with metalized yarns, developed by us earlier. The results of EMR shielding measurements showed that fabrics coated with the paste containing conductive polymer system compared to fabrics with in-weaved conductive metalized yarns have certain advantages as EMR shields.     

Multifunctional iron and iron oxide nanoparticles in silica

Iron and iron oxide nanoparticles in silica layers deposited by sol–gel techniques on Si wafers were formed and studied. It was shown that multifunctional nanoparticles of different iron oxides possessing various physical properties can be fabricated by means of post-growth annealing of (SiO₂:Fe)/SiO₂/Si samples in various atmospheres. The hematite, maghemite, and iron nanoparticles were found to be dominant upon annealing the samples in air, argon, and hydrogen atmosphere, respectively. The physical properties of produced hybrid structures were studied by Raman and FT-IR spectroscopy, spectroscopic ellipsometry, AFM, and magnetic measurements. The sol–gel technique with subsequent annealing procedure is demonstrated to be an effective method for the formation of multifunctional hybrid structures composed of iron or iron oxide nanoparticles in silica matrix.     

Formation and characterization of melt-spun polypropylene fibers with propolis for medical applications

The search of possibilities to improve the functional properties of textile materials has been continuing for years with the aim to provide higher hygiene characteristics offer advanced therapeutic functionality. One of available approaches to provide new properties for textiles is the inclusion of natural ingredients. Propolis extracts are successfully used in practical therapeutics for accelerated wound healing and cell proliferation processes. In this study, pure multi-filament yarns and yarns saturated with propolis were developed and characterized. The effect of preparation and formulation parameters on the characteristics of yarns was evaluated; the release of propolis extract components from yarns and their possible cytotoxicity on cell formation was also determined.     

Unusual Fatty Acids in the Fat Body of the Early Nesting Bumblebee, <Emphasis Type="Italic">Bombus pratorum</Emphasis>

Unusual fatty acids with 24, 26, and 28 carbon atoms were found in triacylglycerols (TAGs) isolated from fat body tissue of bumblebee Bombus pratorum. The most abundant one was (Z,Z)-9,19-hexacosadienoic acid. Its structure was determined by mass spectrometry after derivatization with dimethyl disulfide and by infrared spectroscopy. ECL (equivalent chain length) values of its methyl ester were determined on both DB-1 and DB-WAX capillary columns. (Z,Z)-9,19-Hexacosadienoic acid is quite rare in nature. So far it has been identified only in marine sponges, and this work is the first evidence of its occurrence in a terrestrial organism. HPLC/MS analysis of the bumblebee TAGs showed that (Z,Z)-9,19-hexacosadienoic acid is present in one third of all TAG molecular species. As it was found in all sn-TAG positions, it is likely that (Z,Z)-9,19-hexacosadienoic acid is transported to tissues. Interestingly, labial gland secretion of B. pratorum was found to contain (Z,Z)-7,17-pentacosadiene, a hydrocarbon with markedly similar double bond positions and geometry. Possible biosynthetic relationships between these two compounds are discussed.     

Measurements and analysis of the electromagnetic fields of mobile communication antennas

The owner of a mobile telephone is exposed to radiation from both the mobile telephone and base stations. They are often installed on the roofs of residential buildings. The article deals with electromagnetic fields generated by mobile communication antennas in the residential area. Measurements of electrical strength, magnetic strength and the electromagnetic field energy flux density were performed and compared to the established hygiene norms. Tests were conducted in the near and far zones of the antenna, in residential premises located directly in front of antenna, within the main radiation lobe of the antenna.     

Impact of lipid oxidation-derived aldehydes and ascorbic acid on the antioxidant activity of model melanoidins

As the heat-induced formation of antioxidants throughout the Maillard reaction is known, this study was undertaken to evaluate the impact of lipid oxidation-derived aldehydes and ascorbic acid in Maillard model systems on the resulting antioxidant activity. For this purpose, various fractions of melanoidin-like polycondensation products were obtained from mixtures of amino acids (glycine, lysine, arginine) and lipid oxidation-derived aldehydes (hexanal, (E)-2-hexenal), in the presence or absence of glucose or ascorbic acid. All fractions showed a significant radical scavenging capacity (DPPH assay) and ferric reducing power (FRAP assay). The activity varied according to the composition of the model system tested, although some similar trends were discovered in both assays applied. The presence of lipid oxidation products in the browning products augmented the antioxidant activity in specific cases. For instance, the combined presence of arginine, hexanal and glucose in heated model systems resulted in a significantly higher antioxidant capacity. With an exception of ascorbic acid-containing model systems, melanoidin-like polycondensation products possessed significantly stronger antioxidant activities than the corresponding unheated initial reactant mixtures. Water-soluble high molecular weight (>12kDa) and nonsoluble fractions comprised the major part of the antioxidants derived from amino acid/lipid oxidation product model systems, with or without glucose or ascorbic acid.     

Colossal Magnetoresistance Properties of La0.83Sr0.17MnO3 Thin Films Grown by MOCVD on Lucalox Substrate

The magnetoresistance (MR) of polycrystalline La_0.83Sr_0.17MnO₃ thin films have been studied in high pulsed magnetic fields up to 38 T in the temperature range 100–300 K. The lucalox substrates were used to obtain polycrystalline structures with naturally formed grain boundaries (GBs) and crystallites whose dimensions were determined by film deposition temperature. It was found that the MR value is highest in the films having smallest crystallites. The main behaviour of high-field MR was analysed using modified Mott’s hopping model assuming that the GBs might be ferromagnetic with a Curie temperature T _C being reduced in comparison with that of the crystallites interior.