The Effect of Air Plasma Activated Liquid on Uropathogenic Bacteria

Plasma Chemistry and Plasma Processing - Urinary tract infections (UTI) are often caused by resistant uropathogenic bacteria and can lead to sepsis or chronic renal failure. Cold plasma activated...     

Determination of chromium in the surface nano-layer covering the Zn-based anti corrosion coating of steel sheets using a laser-induced breakdown spectrometry

A method was proposed for the determination of Cr in a thin surface nanolayer deposited on top of a micrometrical Zn-based anticorrosive coating of steel sheets using laser-induced breakdown spectrometry (LIBS). Optimization of the LIBS parameters was performed with respect to the statistical parameters of regression, these being the coefficient of determination (R ²), akaike information criterion and mean-squared prediction error. These were calculated for curves describing the relationship between the Cr surface concentration and the intensity of LIBS signal. The most critical parameter of analysis appears to be the focal spot diameter. When its value was 200 μm and corresponding energy density (fluence) had value of 413.8 J/cm², the intensity–concentration relationship revealed a negative slope. This phenomenon was caused by the difference in total ablated volume for samples with a different content of Cr in the surface layer. This phenomenon was not observed for higher values of the focal spot diameter (400 and 500 μm) and lower values of fluence (103.5 and 66.2 J/cm²). A range of calibration obtained under optimal conditions (focal spot diameter of 400 μm; single pulse mode, laser pulse energy of 130 mJ) was 11–21 mg/m² and the limit of detection was 0.7 mg/m². The recovery values calculated from the results of the proposed LIBS method and the standard ED XRF method ranged from 99.2 to 101%.     

Theoretical study of the HeN2+ 2 dication

The structure and stability of the helio nitrogen molecular dication, HeN²⁺ ₂, is investigated by means of standard quantum chemical methods based on both single-reference and multi-reference formalisms. Sequences of correlation consistent basis sets are employed to establish convergence with respect to the size and the quality of the single-particle basis set. MRCI and CASPT2 calculations are reported for the HeN²⁺ ₂ ground-state ion which is found to be metastable. The barrier for the transition state of the reaction HeN²⁺ ₂→ N⁺ …NHe⁺ → N⁺ + NHe⁺ is calculated to be 59.5 kcals mol^?1. The structure of the transition state NHeN²⁺ was also determined from calculations using the MRCI and CASPT2 methods.     

Spaces of lower semicontinuous set-valued maps

We give a negative answer to Problem 2 posed by R. A. McCoy in his paper [McCoy R. A.: Spaces of lower semicontinuous set-valued maps II, Math. Slovaca 60 (2010), 541–570]. Some topological properties of the space L ^?(X) introduced in [McCOY R. A.: Spaces of lower semicontinuous set-valued maps I, Math. Slovaca 60 (2010), 521–540] equipped with the Vietoris topology are also investigated.     

High throughput method for multielemental analysis of horse hair by oaTOF-ICP-MS

An approach for high throughput reliable multielemental analysis of trace elements in a large number of horse hair samples was designed. Suitability of time-of-flight mass spectrometer (oaTOF-ICP-MS) for fast determination of unlimited numbers of isotopes in the low volume samples was demonstrated. Due to quasi-simultaneous capability of the oaTOF-ICP-MS the large number of highly valuated data with unaffected isotopic ratio in a very short time could be obtained. The choice of horse hair was obvious because of easy reachability and clear conception about horse nutritional habits and stabling. Such large data set with preserved isotopic ratios is ideal for statistical evaluation which could reveal some interesting interconnection between elemental composition of horse hair and the way of stabling, feeding, etc. Statistical treatment of the data is not a part of this study and will be presented later. We collected one hundred horse hair samples from horse stables through Czech Republic. Samples were washed by optimized washing process to eliminate exogenic contamination prior to digestion and following analysis. A determination of 36 elements (As, Au, B, Be, Cd, Ce, Co, Cr, Dy, Er, Eu, Ga, Gd, Ge, Ho, La, Li, Lu, Nd, Ni, Pb, Pd, Pr, Pt, Rb, Sb, Sc, Sm, Ta, Tb, Te, Tm, U, V, Y, Yb) in horse hair by oaTOF-ICP-MS was optimized. A throughput of 100 samples with unlimited numbers of isotopes per 6 h was achieved. Proposed very fast multielemental method preserves isotopic ratios, and therefore, is undoubtedly highly suitable for statistical studies. Detection limits of the proposed method ranged from 0.13 μg kg^?1 (Eu, Gd, Tm) to 27.9 μg kg^?1 (Au), except for Ni (48.5 μg kg^?1) that is probably affected by contamination raised from nickel cones.     

A practical approach to non-spectral interferences elimination in inductively coupled plasma optical emission spectrometry

Matrix effects and practical possibilities of reducing accompanying non-spectral interferences in inductively coupled plasma optical emission spectrometry (ICP-OES) were studied for microconcentric Micromist, concentric and V-groove nebulizers (VGN) coupled with two cyclonic spray chambers of different sizes. The effect of a wide scale of interferents and mixtures thereof in the concentration range of up to 2 mass % (Na, Ca, Ba, La, urea) or up to 20 vol. % (nitric acid) on the analysis of Cd, Cu, K, Mg, Mn, Pb and Zn was investigated in terms of their analytical recovery and Mg(II) 280.27 nm/Mg(I) 285.29 nm line intensity ratio. Recoveries of ionic lines were lower than those of atomic lines (37–102 %) depending on the matrix concentration. The Mg(II)/Mg(I) ratios were found to be 12–15 and they slightly decreased as the matrix load increased. Exceptional behavior of pure La matrix, steeply lowering the recoveries and Mg(II)/Mg(I) ratios was observed. A Micromist nebulizer coupled with a small inner volume spray chamber provided the highest recoveries (94–102 %), lowest matrix effects across the matrix loads and, compared to others, the least significant dependence without worsening of the analytical characteristics (recoveries, signal background ratios and the Mg(II)/Mg(I) ratios) across the studied matrices.     

Impregnated fly ash sorbent for cesium-137 removal from water samples

Journal of Radioanalytical and Nuclear Chemistry - Cesium-137 is an important indicator of radioactive pollution in the aquatic environment. The aim of this study was to increase the sorption...     

Effects of enzymes and hydrocolloids on physical, sensory, and shelf-life properties of wheat bread

This study compares two types of enzymes: maltogenic amylase (Novamyl 10000 BG) and lipase (Lipopan F BG, Lipopan Xtra BG), both separately and in combination, and seven hydrocolloids (guar gum, xanthan gum, carrageenan, β-glucan, carob gum, and carboxymethyl cellulose (CMC)) on the physical and sensory properties of a bakery product (white wheat bread). Their effect was observed on the baking characteristics of volume, specific volume, shape, mass, shelf-life (penetration and water activity test), and overall taste. The best results in shelf-life extension from the hydrocolloids were shown by β-glucan, a combination of xanthan gum + carrageenan and guar gum. From the enzymes, the best results were achieved with Lipopan Xtra BG and Novamyl 10000 BG + Lipopan F BG combination. The sensory properties (e.g. taste, colour, shape, aroma, elasticity, hardness) were evaluated by ten trained panellists, holding certification in sensory analysis. β-Glucan and Novamyl 10000 BG + Lipopan F BG combination increased the bread volume significantly and also were deemed to afford the most favourable taste.