Cesium leaching from gamma-irradiated CsA and CsX zeolites

The present study discusses the effect of γ-irradiation on Cs⁺-exchanged X and A zeolites. The incorporation of Cs⁺ ions into A and X zeolites was performed using three different cesium salts (chloride, nitrate or acetate). Cs⁺ ions immobilized into the vitrified zeolites by thermal treatment are located in different sites of the zeolite networks. It is found that γ-irradiation favors cesium retention depending on the cesium precursor salt used in the cationic exchange step.     

Polymer-interaction driven diffusionof eyeshadow in soft contact lenses

Soft contact lenses used for the correction of ametropia are often made of hydrogel and silicone-hydrogel materials. Since they are placed directly on the surface of the eye and they are hydrated by tears, eye cosmetics can compromise the lens performance and, even worse, can be transported from an external environment to the ocular surface through the contact lens.The diffusion of the dye component of a purple eyeshadow in soft contact lenses of different materials is here evaluated. Diffusivity is found to be typically higher in silicone-hydrogels than in hydrogels. In hydrogels, diffusivity is greater in the case of lower oxygen transmissibility. Despite differences between materials, absorbed mass of dye is much larger (10–100 times) than the expected mass by simple hydration and swelling of the contact lens. The most contaminated materials are also resistant to cleaning solutions. The results indicate that, notwithstanding the complexity of contact lens networks, diffusion of dye is found to follow Fick’s law and it is driven by polymer-dye interaction, which governs lens hydration and swelling.     

Intelligent and Good Machines? The Role of Domain and Context Codification

Mobile Networks and Applications - There is a core problem with the modern Artificial Intelligence (AI) technologies, based on the current new wave of Artificial Neural Networks (ANNs). Whether...     

Assessment of activated sludge viability with flow cytometry

The aim of the study was to evaluate the applicability of fluorescent dyes and multiparameter flow cytometry for the rapid and direct viability/activity assessment of activated sludge samples taken from wastewater treatment plants. Viability and activity of the biomass were estimated respectively through cellular membrane integrity, staining with SYBR Green I and Propidium Iodide, and through fluorogenic dyes capable of detecting enzymatic activity, as FDA and BCECF-AM. A procedure has been developed to disaggregate sludge flocs before dyes staining and cytometric analysis. The developed procedure allows a high recovery of bacteria with good accuracy and repeatability, and minimize the damage of the cells suspension obtained from the disaggregation of the flocs. These measurements were applied to estimate the two main parameters required to define the biological activated sludge process: the endogenous decay rate and the specific growth rate in exponential phase with high F/M ratio. Oxygen utilization rate measurements (OUR) were conducted to conventionally monitor the activity of the biomass. The preliminary data are encouraging and support the possibility to investigate bacteria dynamics on wastewater treatment plants.     

How (do) internal capabilities and the geography of business networks shape the performance of contractors in public procurement tenders? Evidence from the construction industry

Public procurement tenders (PPTs) represent one of the largest sources of income for construction companies; the identification of factors that could favour the winning of these projects becomes more and more interesting. Our work aims to explore how firm-specific capabilities (project management, project administration and innovation) and the geography of its business network shape the success of contractors in winning PPTs, measured as the average value of projects won by the firms. We propose an empirical study of contractors involved in public procurement projects in the construction industry in three Italian regions from 2008 to 2012 employing a fuzzy set qualitative comparative analysis. This methodology allows analysing how different combinations of causal conditions contribute to an outcome. Our research highlights that there are three successful strategies for firms attempting to obtain high-value PPT projects: (1) invest in high-level project management capabilities, engage in business networks with distant clients and intensify innovation capacity; (2) invest in high-level project administration capabilities, engage in business networks with local clients and suppliers (within 100 km), report a large number of certifications and show a high innovation capacity; and (3) invest in growth strategies to increase the size of the company.     

Natural contamination with arsenic and other trace elements in ground waters of Argentine Pampean Plain

Natural contamination with arsenic and other toxic trace elements was studied on a 50,000 km(2) area of the Pampean Plain in Argentina. The locations where natural sources of arsenic are considered to be of concern continue to grow, and include those associated with soils developed on loess or loessic sediments zones and transported volcanic materials sites. Contents of total arsenic, vanadium, chromium, iron and barium higher than those recommended as maximum allowable levels in drinking waters have been measured. In the case of arsenic, analyses of raw groundwaters yielded levels as high as 600 microg As/l. Reported data are discussed in connection with geological and environmental processes involved in ground water contamination.     

Photoconducting Bragg Mirrors based on TiO2 Nanoparticle Multilayers

A synthetic route to building photoconducting films of TiO₂ nanoparticles that display bright structural color is presented. The color arises as a result of the periodic modulation of the refractive index, which is achieved by controlling the degree of porosity of each alternate layer through the particle size distribution of the precursor suspensions. The suspensions are cast in the shape of a film by spin‐coating, which allows tailoring of the lattice parameter of the periodic multilayer, thus tuning the Bragg peak spectral position (i.e., its color) over the entire visible region. Photoelectrochemical measurements show that the Bragg mirrors are conductive and distort the photocurrent response as a result of the interplay between photon and electron transport.     

Donkey’s milk protein fractions characterization

Donkey’s milk may be considered a valid alternative, for infant nutrition, to powdered milks, soybean milk or other formulas, since its composition in lipids and proteins is very close to human milk. The aim of the present study is to characterize “donkey’s milk” product, especially with regard to the protein fractions. Three different chromatographic approaches for donkey’s milk proteins separation are described, based on their different isoelectric points, hydrophobicity and molecular mass. The proteins obtained were further separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis and identified by N-terminal sequencing. α_S1- and β-caseins, lysozyme, α-lactalbumin, β-lactoglobulin were identified. Furthermore, the content of α-lactalbumin, β-lactoglobulin, and lysozyme in donkey’s milk was determined by a reversed-phase HPLC method. The β-lactoglobulin and α-lactalbumin content was 3.75 and 1.8 mg/ml, respectively (mean values). The present study showed the nutritional properties of donkey’s milk characterized by low casein and high lysozyme content (1.0 mg/ml) compared with other kinds of milks.