Characterization of CaTi0.9Fe0.1O3/La0.98Mg0.02NbO4 composite

A composite of CaTi_0.9Fe_0.1O₃ and electrolyte material, i.e. magnesium doped La_0.98Mg_0.02NbO₄ was prepared and studied. The phase content and the sample microstructure was examined by an X-ray diffraction method and scanning electron microscopy. EDS measurements were done both for composite samples and the diffusion couple. The electrical properties were studied by four terminal DC method. The high-temperature interaction between the two components of the composite has been observed. It has been suggested that lanthanum diffused into the perovskite phase and substituted for calcium whereas calcium and niobium formed the Ca₂Nb₂O₇ pyrochlore phase. At 1500°C very large crystallites of the pyrochlore were observed. Regardless of strong interaction between the composite components, its total conductivity was weakly dependent on the sintering temperature.     

Capillary electrophoresis in the diagnosis of surgical site infections

A surgical site infection (SSI) is an infection that occurs after surgery in the part of the body where the surgery took place. An SSI may range from a spontaneously limited wound discharge within 7–10 days of an operation to a life‐threatening postoperative complication, such as a sternal infection after open heart surgery. Most SSIs are caused by contamination of an incision with microorganisms from the patient's own body during surgery. From the analytical point of view, the complex nature of these samples as well as the low concentrations of analytes require a system with high sensitivity and efficiency. Such situation requires a technique such as CE, which is a powerful and versatile separation technique that promises to rival HPLC when applied to the separation of both charged and neutral species. During the study, it has been demonstrated that CZE identifies characteristics of such groups of pathogens such as bacteria Gram (+) and different species of bacteria Gram (?), and also develops weekly individual profiles for patients after application of antibiotics. This was done in order to show the impact of antibiotic therapy in change “numbers” of bacteria present in the wound after surgery. The method proved to be the ideal straight specificity in the case of Escherichia coli (100%). Finally, analysis of the spectra and the second derivatives of the UV‐Vis spectra confirmed the similarity in the profiles and showed that the CZE is a great method for fast screening test in bacterial infection.     

Investigation of the solubilization of car-emitted Pt,Pd and Rh in street dust and spiked soil samples

A sequential extraction procedure (three-step), proposed by the Standards, Measurements and Testing Programme (formerly BCR) of the European Union, was applied to street dust and spiked soil samples for the determination of PGEs. Analyses were carried out using inductively coupled plasma-mass spectrometry (ICP-MS). The results indicate that up to 5% from Pt, 70% from Pd and 14% from Rh are in mobile forms in street dust. The results for the soil samples spiked with crushed catalytic converter are significantly lower indicating that PGEs are oxidised more efficiently in natural conditions. Additionally Pt and Pd bound to humic acids were investigated.     

Urine sample preparation for proteomic analysis

Sample preparation for both environmental and more importantly biological matrices is a bottleneck of all kinds of analytical processes. In the case of proteomic analysis this element is even more important due to the amount of cross‐reactions that should be taken into consideration. The incorporation of new post‐translational modifications, protein hydrolysis, or even its degradation is possible as side effects of proteins sample processing. If protocols are evaluated appropriately, then identification of such proteins does not bring difficulties. However, if structural changes are provided without sufficient attention then protein sequence coverage will be reduced or even identification of such proteins could be impossible. This review summarizes obstacles and achievements in protein sample preparation of urine for proteome analysis using different tools for mass spectrometry analysis. The main aim is to present comprehensively the idea of urine application as a valuable matrix. This article is dedicated to sample preparation and application of urine mainly in novel cancer biomarkers discovery.     

Antimicrobial properties of biosynthesized silver nanoparticles studied by flow cytometry and related techniques

This work reports the effect of silver bionanoparticles (Bio(AgNPs) synthesized by Actinobacteria CGG 11n on selected Gram (+) and Gram (–) bacteria. Flow cytometry, classical antibiogram method and fluorescent microscopy approach was used for evaluation of antimicrobial activity of Bio(AgNPs) and their combination with antibiotics. Furthermore, the performed research specified the capacity of flow cytometry method as an alternative to the standard ones and as a complementary method to electromigration techniques. The study showed antibacterial activity of both BioAgNPs and the combination of antibiotics/BioAgNPs against all the tested bacteria strains in comparison with a diffusion, dilution and bioautographic methods. The synergistic effect of antibiotics/BioAgNPs combination (e.g. kanamycin, ampicillin, neomycin and streptomycin) was found to be more notable against Pseudomonas aeruginosa representing a prototype of multi‐drug resistant “superbugs” for which effective therapeutic options are very limited.     

Beiträge zur Chemie der Silicium-Schwefel-Verbindungen. 46 [1]. 29Si-NMR-chemische Verschiebungen von Trialkoxysilylthioderivaten der Permethylpolysilane

Contributions to the Chemistry of Silicon-Sulphur Compounds. 46. ²⁹Si-N.M.R. Chemical Shifts of Trialkoxysilylthio Derivatives of Permethylpolysilanes ²⁹Si-N.M.R. chemical shifts of trialkoxysilythio derivatives of permethylpolysilanes of the two series: α, ω-(RO)₃SiS(SiMe₂)_nSSi(OR)₃, n = 2, 3, 4, 6 and 1-(RO)₃SiS(SiMe₂)_nMe, n = 2, 4; R = i-Pr, t-Bu and also ³¹C-NMR shifts are given. The relationship of ²⁹Si-NMR chemical shift from the netto charge at the silicon atom q(Si) which value has been corrected according to the Sandorfy C quantum-chemical model is discussed. The greater reduction of the electron density at silicon in compounds with Si? X bond (X = S, P, Cl) has been explained by a conjugation of the lone of sulphur with the Si? X bonding pair.     

Dynamics of a surface phase transition as monitored by in situ second harmonic generation

The dynamics of the (2 x 2)-3CO <--> dilute phase transition involving CO adsorbed on Pt(111) microfacets has been monitored in situ in a CO-saturated acidic electrolyte using potential step-second harmonic generation techniques. Apparent time constants derived strictly from the optical data were found to be orders of magnitude slower for the forward process as compared to those of the reverse process. This behavior is consistent with the activated nature of CO electrooxidation, which requires the presence of a neighboring adsorbed oxygenated species, for example, hydroxyl, for the process to ensue.     

Determination of volatile and non-volatile products of milk fermentation processes using capillary zone electrophoresis and solid phase microextraction coupled to gas chromatography

The aim of the investigations was to develop analytical methods for the determination of selected volatile and non-volatile organic compounds numbering among the final products of milk fermentation. The analyzed compounds were as follows: biacetyl and carboxylic acids (formic, acetic, citric, and lactic). The model yogurt was prepared under controlled conditions in our laboratory by addition of the selected bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) to the milk sample. The temperature, time, and stirring were controlled during the fermentation process. Factors considered in SPMPE-GC-FID method development included fiber exposure time, salt addition, temperature of extraction, and temperature of desorption. Various SPME fibers, for example with PDMS, CAR/PDMS, PA, and PDMS/DVB coatings, were tested to obtain the highest recovery of the investigated compounds extracted from yogurt samples. Based on these preliminary experiments, qualitative and quantitative analyses for the determination of biacetyl were performed by SPME-GC-FID. Moreover, a capillary zone electrophoresis method was developed for the determination of carboxylic acids in the yogurt samples. The buffer composition as well as deproteinization by acetonitrile were found to have a crucial effect on the analysis.