Mercury associated with size-fractionated urban particulate matter: three years of sampling in Prague, Czech Republic

An analysis of suspended particulate matter, with an emphasis on the Hg chemical forms, is presented. Dust samples originating from an area highly affected by traffic pollution in the city of Prague (Czech Republic) were sampled over a period of three years from air-conditioner filters and fractioned by size. The samples were morphologically characterised by scanning electron microscopy. The main method used for the analysis of constituent mercury compounds was sequential extraction by leaching solutions in combination with thermal desorption. The total mercury content ranged from 0.37 mg kg^?1 to 0.82 mg kg^?1. It emerged that the mercury was distributed in a wide spectrum of forms, and various trends in the distribution of these forms among the different size classes were observed. The fraction leached by nitric acid (consisting of elemental and complex-bound mercury) was the main constituent of total mercury. The highest content of this fraction was observed in the finest particle size class. The heterogeneity of morphology of the material increased with the size fraction.     

Reversible Phosphorylation of Trimethylsilylisothiocyanate

Abstract

The reaction of trimethylsilylisothiocyanate with phosphorus acids chlorides was demonstrated to be reversible.     

Synthesis and Thermal Transformations of 1-Polyfluoro-Alkyl-2-Trialkylsilylethyl Esters of Phosphorus Acids

Abstract

We have studied the phosphorylation of 1-polyfluorólkyl-2-trialkylsilylethanols (I) with phosphorus acids chlorides.     

Three-Stage Extraction of Gelatines from Tendons of Abattoir Cattle: 2—Properties of Gelatines

The subject of our previous paper (part 1) was three-stage extraction of gelatines from short cattle tendons. In this paper, we studied influence of extraction conditions on quality of produced gelatines??protein content, ash content, rigidity of gelatine gels, viscosity, and distribution of molecular weights. Ash content of gelatines ranged in limits 3.5?C10.5?%. Rigidity of the gels was influenced by extraction conditions and by elastin content in gelatines; highest-quality gels display rigidity of 213 Bloom. Viscosity of gelatines ranged from 2.47 to 12.11?mPa?s. Molecular weights of gelatines display a proportion of fractions from 20 to 36?kDa, a quite high proportion of fractions from approximately 50 to 100?kDa, in some cases even fractions above 200?kDa appear. It was found that transition temperature and melting temperature of gelatines extracted from tendons are in accord with data on gelatines obtained by traditional extraction techniques from skins and bones. With respect to efficiency of the whole extraction process and to quality of extracted gelatine, we may recommend extraction conditions as follows: in the 1st processing stage, shaking degreased starting material with water in ratio 1:10 at 25?°C for 5?h; in the 2nd stage, treating the swelled material with 5?% (w/w) added proteolytic enzyme at 40?°C for 25?h; in 3rd stage, extracting gelatine while boiling for 16?min.     

Tuning the morphology and magnetic properties of single-domain SrFe8Al4O19 particles prepared by a citrate auto-combustion method

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Perimidine-based synthetic receptors for determination of copper(II) in water solution

Perimidine-based chelators 1 and 2 were prepared, and their structures were confirmed by ¹H and ¹³C NMR, MS spectroscopy and elemental analysis. These compounds were studied as specific synthetic receptors for the recognition of transition metal ions. They exhibited high affinity and selectivity towards Cu(II) ions. The conditional binding constants, linear dynamic range and detection limit were determined by UV–vis spectroscopy. These parameters demonstrated high potential of the prepared synthetic receptors for the recognition and determination of Cu(II) ions. The minimum detectable concentrations of Cu(II) ions for the synthetic receptors 1 and 2 were 270 and 75 nM (R ² = 0.9915 and 0.9964) in aqueous medium (water/DMSO; 99:1 (v/v)), respectively.     

Classical BV Theories on Manifolds with Boundary

In this paper we extend the classical BV framework to gauge theories on spacetime manifolds with boundary. In particular, we connect the BV construction in the bulk with the BFV construction on the boundary and we develop its extension to strata of higher codimension in the case of manifolds with corners. We present several examples including electrodynamics, Yang-Mills theory and topological field theories coming from the AKSZ construction, in particular, the Chern-Simons theory, the BF theory, and the Poisson sigma model. This paper is the first step towards developing the perturbative quantization of such theories on manifolds with boundary in a way consistent with gluing.