The comparison of sample extraction procedures for the determination of cations in soil by IC and ICP-AES

This paper presents the extraction of cations from a soil sample, type ranker on serpentinite, in deionized water, by use of three different extraction techniques. The first extraction technique included the use of a rotary mixer, the second technique involved the use of a microwave digestion system with different extraction temperatures, and the third technique employed an ultrasonic bath with different extraction times. Ion chromatography was used for determining the concentration of Li, Na, K, Ca, Mg and ammonium ions in soil extracts with subsequent determination of concentrations for all cations, except for ammonium ion extraction, conducted by Inductively Coupled Plasma-Atomic Emission Spectrometry. The results of cation extractions showed that microwave assisted extraction was most efficient for the Li, Na, K, Ca, Mg, Co, Mn, Ni, Pb and ammonium ions. Use of a rotary mixer for extraction was most efficient for Cd and Zn ions, while use of ultrasound bath was most efficient for Cr, Cu, Fe and Al ions. Several times higher amount of cations extracted by the most efficient, compared to the second best technique, under optimal conditions, were noticed in the case of: Ca, Mg, Co, Mn, Fe, Al, and Zn ions.     

Chemical composition and antimicrobial activity of Satureja kitaibelii essential oil against pathogenic microbial strains

Plant species Satureja kitaibelii Wierzb. ex Heuff. is used as a spice and as a natural preservative for food and herbal tea, owing to its characteristic scent and flavor as well as high antimicrobial activity. In the present study, the antimicrobial activity of isolated essential oil of S. kitaibelii was tested against a panel of 30 pathogenic microorganisms (foodborne microbes, selected multiresistant bacterial isolates from the patient wounds and dermatophyte isolates). Limonene (15.54%), p-cymene (9.99%), and borneol (8.91%) appeared as the main components in 44 identified compounds representing 98.44% of the oil. Essential oil of S. kitaibelii showed significant activity against a wide spectrum of foodborne microbes (MIC=0.18-25.5 microg mL(-1)) and multiresistant bacterial isolates (MIC=6.25-50.0 microg mL(-1)), as well as against dermatophyte strains (MIC=12.5-50.0 microg mL(-1)). These results demonstrate that S. kitaibelii essential oil could be used as a natural potential antimicrobial agent against pathogenic strains in the treatment of foodborne disease, wound and skin infections.     

Canonizing structural Ramsey theorems

At the beginning of 1950s Erd?s and Rado suggested the investigation of the Ramsey-type results where the number of colors is not finite. This marked the birth of the so-called canonizing Ramsey theory. In 1985 Prömel and Voigt made the first step towards the structural canonizing Ramsey theory when they proved the canonical Ramsey property for the class of finite linearly ordered hypergraphs, and the subclasses thereof defined by forbidden substructures. Building on their results in this paper we provide several new structural canonical Ramsey results. We prove the canonical Ramsey theorem for the class of all finite linearly ordered tournaments, the class of all finite posets with linear extensions and the class of all finite linearly ordered metric spaces. We conclude the paper with the canonical version of the celebrated Ne?et?il–Rödl Theorem. In contrast to the “classical” Ramsey-theoretic approach, in this paper we advocate the use of category theory to manage the complexity of otherwise technically overwhelming proofs typical in canonical Ramsey theory.     

The Existing Methods and Novel Approaches in Mycotoxins’ Detection

Mycotoxins represent a wide range of secondary, naturally occurring and practically unavoidable fungal metabolites. They contaminate various agricultural commodities like cereals, maize, peanuts, fruits, and feed at any stage in pre- or post-harvest conditions. Consumption of mycotoxin-contaminated food and feed can cause acute or chronic toxicity in human and animals. The risk that is posed to public health have prompted the need to develop methods of analysis and detection of mycotoxins in food products. Mycotoxins wide range of structural diversity, high chemical stability, and low concentrations in tested samples require robust, effective, and comprehensible detection methods. This review summarizes current methods, such as chromatographic and immunochemical techniques, as well as novel, alternative approaches like biosensors, electronic noses, or molecularly imprinted polymers that have been successfully applied in detection and identification of various mycotoxins in food commodities. In order to highlight the significance of sampling and sample treatment in the analytical process, these steps have been comprehensively described.     

Spectroscopic and Theoretical Study of Cyanidin–Aluminum (III) Complexes

Complexation of aluminum (III) with cyanidin, a natural anthocyanidin molecule, has been investigated in methanol and buffered solutions of pH 3.0 and 4.0. Electronic absorption spectroscopy was performed to characterize the stoichiometry and stability of the complexes formed. In investigated solvents, aluminum bonded moderately to cyanidin requiring large mole ratios of the components (up to 200) for the access of complexation. Molar ratio plots showed the formation of only one complex with stoichiometry aluminum (III):cyanidin of 1∶1 in both investigated media. Semiempirical calculations, performed in the Austin Model 1 parameterization, enabled the determination of the structural features of free compounds as well as complex structural modifications caused by chelation of Al(III).     

Additive results for the generalized Drazin inverse in a Banach algebra

In this paper we investigate additive properties of the generalized Drazin inverse in a Banach algebra. We find some new conditions under which the generalized Drazin inverse of the sum a + b could be explicitly expressed in terms of a, a^d, b, b^d. Also, some recent results of Castro and Koliha [New additive results for the g-Drazin inverse, Proc. Roy. Soc. Edinburgh Sect. A 134 (2004) 1085-1097] are extended.     

Double donor in a spherical quantum dot

We present a variational calculation for the ground state of the double donor in a spherical GaAs–Ga_1–x Al _x As quantum dot. The binding energies for the ionized and neutral centres are calculated for several barrier height values as a function of the radius of the dot. Compared with a square well structure, there is a stronger confinement and a larger binding energy for the double donors in a spherical quantum dot.     

Polyelectrolyte complexes. V. Solid‐state properties of some polycation/azo dye complexes controlled by the dye structure

The solid‐state properties of some polycation/azo dye complexes according to the dye structure were studied in this work. One polycation contained about 95 mol % N,N‐dimethyl‐2‐hydroxypropyleneammonium chloride units in the backbone (PCA₅), and eight azo dyes, different in either the number of sulfonic groups or their distribution, were used as opposite components. The selected azo dyes were as Crystal Scarlet, Congo Red, Crocein Scarlet MOO, Ponceau SS, Amaranth, Ponceau S, Direct Blue 1, and Direct Red 80. Information on the compensation degree of the oppositely charges was obtained by the elemental analysis of the solid‐state polycation/dye complexes (the experimental contents of chlorine, nitrogen, and sulfur were compared with the calculated values). Differential scanning calorimetry was employed to probe the strength of the intermolecular interactions in the PCA₅/dye complexes. Wide‐angle X‐ray diffraction was used to assess the supramolecular order of the solid‐state complexes. The physical properties of the PCA₅/azo dye complexes (the complex stoichiometry, glass‐transition temperature, decomposition temperature, and degree of supramolecular order) were influenced mainly by the dye structure but also by the polycation concentration and the presence of NaCl. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 264–272, 2003     

Univalent Interpolation in Besov Spaces and Superposition into Bergman Spaces

We establish the best possible condition for point singularities to be removable for nonlinear elliptic equations in divergent form with lower order terms from the non-linear Kato classes.