Microbiological quality of Italian beach sands

The paper deals with the potential sanitary risk of the human presence on the seaside. The levels of microbial contamination of beach sands are generally higher than those observed in the waters due to bioaccumulation phenomena. The diseases, which could be contracted through skin contact, are related to the potential infecting dose and the most widespread illnesses are a consequence of several species of fungi and bacteria inhabiting the coastline. Despite few studies have been performed to determine Guideline Values, preventive measures and health risk assessments should be considered.     

Space charge limited avalanche growth in multigap resistive plate chambers

The European Physical Journal C - The ALICE TOF array will be built using the Multigap Resistive Plate Chamber(MRPC) configured as a double stack. Each stack contains 5 gas gaps with width of...     

Evaluation of sample preparation protocols for proteomic analysis of sunflower leaves

Six protocols for extraction of proteins from sunflower (Helianthus annuus L.) leaves were evaluated for their abilities in both removing interferents and attaining the best resolution in two-dimensional gel electrophoresis. “Classical” phenol extraction followed by precipitation with ammonium acetate in methanol displayed the most efficient protocol, which allowed the detection of 244 protein spots with ca. 485 μg of protein in gel electrophoresis. Tandem mass spectrometry was performed to identify proteins in 61 spots, and cross species identification was used for this task. Proteins from twenty two spots were identified, and 12 of these proteins are up to now not included into the ExPASy sunflower protein databank.     

Identification of selenium in the leaf protein of sunflowers by a combination of 2D-PAGE and laser ablation ICP-MS

We report on a method for the identification of selenium-containing proteins in an extract of sunflower leafs. It is based on the separation of the proteins by 2-dimensional gel electrophoresis, followed by detection of selenium via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The laser system was operated in a raster mode at 100?μm?s^-1 and proved to be an efficient alternative in the search for selenoproteins in the spots of the gels. The instrumental parameters were optimized in terms of plasma energy and application of optimal reaction cell conditions, and the detection of the mass ⁸⁰Se¹⁶O⁺ which enabled the elimination of interfering species. Selenium was identified in 9.6% of the analyzed spots, indicating its random incorporation into the primary structure of the proteins.

Gaseous sample introduction for the determination of silicon by ICP-AES

The generation of volatile species of silicon as a means to introduce silicon into an inductively coupled plasma has been studied. It is based on the reaction between silicon and fluoride ions in sulfuric acid media and it was carried out using different flow injection mountings. The first mounting works with an injection of 100 μL concentrated sulfuric acid and 150 μL silicon standard solution in a continuous 0.05 mol L^–1 NaF solution flow. The method shows a linear response between the intensity of emission at 251.611 nm line and the silicon concentration from 0.1 to 200 μg mL^–1, with a reproducibility of 2% and a detection limit of 0.004 μg mL^–1. The second mounting produces the volatile species by the reaction between two opposed aerosol flows in a home-made nebulization chamber. This chamber has a Cross-Flow and a Meinhard nebulizer at either end. A linear response ranging from 0.1 to 1000 μg mL^–1 of silicon solution is obtained and the reproducibility rises to 8%.The detection limit reached is 0.02 μg mL^–1. The silicon content in real water samples was determined by applying both the above-mentioned methods and a third method for reference. Received: 6 November 1996 / Revised: 19 December 1996 / Accepted: 3 January 1997     

Specific heat spectra of non-interacting fermions in a quasiperiodic ladder sequence

We compute the specific heat spectra of non-interacting fermions whose energy spectrum was obtained from a quasiperiodic ladder sequence (Fibonacci and Rudin-Shapiro type), mimicking a DNA molecule model. The specific heat is calculated from their underlying multi-fractal energy spectrum, considering several values of energy densities. Comparisons are made with a real DNA sequence, namely the human chromosome 22 (Ch22).     

Magnetic polaritons in metamagnet layered structures: Spectra and localization properties

The magnetic polariton propagation in metamagnet layered structures is theoretically studied by using a transfer matrix approach. The layered structures considered here are made up by the stacking of two different layers (also known as building blocks, named A and B), where one of them is a metamagnetic thin film (A), while the other is a non-magnetic insulator thin layer (B). We take into account both the antiferromagnetic (AFM) and ferromagnetic (FM) phases of the metamagnetic material. For the periodic arrangement, the bulk modes are characterized by two large symmetric bands, with non-reciprocal surface modes between them. The quasiperiodic metamagnetic structure is then built up by following the Fibonacci sequence, whose long-range order effect is then investigated, giving rise to an interesting self-similar spectra and a power-law profile.