Environmental heterogeneity patterns and assessment of trophic levels in two Mediterranean lagoons: Orbetello and Varano, Italy

The management of coastal lagoons is of particular interest due to their high economical importance. In spite of their great productivity, coastal lagoons are often impacted by human pressure which produces water eutrophication. The aim of this paper is to assess the trophic state of the two Mediterranean lagoons taking into account chemical-physical parameters, nutrient concentrations and biological parameters. Two Italian lagoons, Orbetello and Varano (respectively located in Tyrrhenian and Adriatic coast, Italy) were studied between May 2003 and April 2005. Both these systems receive treated urban outflows, agricultural effluents and rivers freshwater inputs. Field collected data showed that studied lagoons were characterized by different human and natural pressures. Orbetello showed the highest water eutrophication, highlighted by the trophic index values, while Varano showed lower eutrophication levels except for the summertime. The values of physical, chemical and biological parameters measured in Orbetello and Varano lagoons indicate that a wide spatial and seasonal gradient of the water characteristics was established during the study period, but in particular in winter. This gradient, typical of estuarine systems, was essentially due to the mixing of freshwater, seawater and anthropogenic inputs. Orbetello lagoon seemed much more affected by the urban impact and the fish-farming activities than Varano lagoon, but the latter showed a greater agriculture activities impact as showed by the remote sensing images.     

A new competitive fluorescence assay for the detection of patulin toxin

Patulin is a toxic secondary metabolite of a number of fungal species belonging to the genera Penicillum and Aspergillus. It has been mainly isolated from apples and apple products contaminated with the common storage-rot fungus of apples, Penicillum expansum, but it has also been extracted from rotten fruits, moldy feeds, and stored cheese. Human exposure to patulin can lead to serious health problems, and according to a long-term investigation in rats, the World Health Organization has set a tolerable weekly intake of 7 ppb body weight. The content of patulin in foods has been restricted to 50 ppb in many countries. Conventional analytical detection methods involve chromatographic analyses, such as HPLC, GC, and, more recently, techniques such as LC/MS and GC/MS. However, extensive protocols of sample cleanup are required prior to the analysis, and to accomplish it, expensive analytical instrumentation is necessary. An immunochemical analytical method, based on highly specific antigen-antibody interactions, would be desirable, offering several advantages compared to conventional techniques, i.e., low cost per sample, high selectivity, high sensitivity, and high throughput. In this paper, the synthesis of two new derivatives of patulin is described, along with their conjugation to the bovine serum albumin for the production of polyclonal antibodies. Finally, a fluorescence competitive immunoassay was developed for the on-line detection of patulin.     

FRP confinement of masonry: analytical modeling

International and National Building Codes provide requirements for design and construction of new masonry structures, but design provisions for the repair, retrofitting, and rehabilitation of masonry structures are not always available and included in the same documents. Due to the extremely large variability in masonry performances, equations of general validity cannot often be provided, namely relationships suitable for every masonry type. Despite the great research effort in the experimental field, considerable theoretical work is still needed to fully outline a definitive analytical model to predict the behavior of FRP confined masonry. Most of the available models, empirical in nature, have been calibrated against their own sets of experimental data, or they are simply derived from concrete. Even if large amount of results obtained for concrete led to consolidated design guidelines, they cannot be simply extended to masonry. In this study, a mechanically based confinement model is proposed based on mechanical parameters able to differentiate similar masonry types and to highlight that they present different confinement performance. Crucial aspects of masonry confinement will be also discussed, namely: lateral dilation; confinement effectiveness; lateral pressure also in non-circular shapes; effective strain of FRP.     

Distributed Coordination and Workflow on the World Wide Web

This paper describes WebFlow, an environment thatsupports distributed coordination services on theWorld Wide Web. WebFlow leverages the HTTP Webtransport protocol and consists of a number of toolsfor the development of applications that require thecoordination of multiple, distributed servers.Typical applications of WebFlow include distributeddocument workspaces, inter/intra-enterprise workflow,and electronic commerce. In this paper we describe thegeneral WebFlow architecture for distributedcoordination, and then focus on the environment fordistributed workflow.     

Effect of laser microcutting on thermo-mechanical properties of NiTiCu shape memory alloy

The machining of shape memory alloys (SMAs), such as NiTi based alloys, is a very interesting and relevant topic for several industrial applications in the biomedical, sensor and actuator fields. Laser technology is one of the most suitable methods for the manufacturing of products in the aforementioned fields, mainly when small and precise features have to be included. Due to the thermal nature of this process, study of its effect on the functional properties of these materials is needed. Except for binary NiTi, few results on the laser machining of NiTi based alloys are available in the literature. In this work, thin sheets of Ni40Ti50Cu10 (at.%) were processed by a fibre laser and the effect of process speed on the material properties was analysed. Scanning electronic microscopy was adopted for observation of the laser cut edges’ morphology. Chemical composition of the processed material was evaluated by energy dispersion spectroscopy and nanohardness measurements were used to estimate the heat affected zone. SMA functional properties were studied on both base and laser machined material. These characteristics are affected by laser machining for the presence of melted material; this effect can be minimised by increasing the laser process speed.     

Distribution of serotypes and pulsotypes of Listeria monocytogenes from human,food and environmental isolates (Italy 2002–2005)

This work was undertaken to study the serotypes and pulsotypes of 674 Listeria monocytogenes isolates from human (57), food (558) and environmental (59) sources, collected from different Italian geographical areas during 2002–2005, to determine whether certain subtypes were associated with certain foods and more often involved in cases of listeriosis, and to determine possible geographical or temporal associations. Eleven different L. monocytogenes serotypes were found in the food, environmental and human isolates. Most isolates belonged to only four serotypes (1/2a, 1/2b, 1/2c, 4b). The isolates were divided into 133 distinct AscI pulsotypes grouped into 26 pulsogroups. Pulsogroups ranged from a minimum of 2 up to 212 isolates, and contained 1–19 different pulsotypes. When associations between subtypes and isolates from specific foods selected as being most frequently involved in cases of listeriosis were tested some of these associations were highly significant but not exclusive, indicating that there was no close correlation between specific subtypes and specific food products. Despite the limitations of this study (few human isolates versus many food isolates prevalently collected from one food category), we believe that a large-scale database of L. monocytogenes subtypes and a timely epidemiological investigation can facilitate risk assessment and outbreak detection and control.     

Influence of water on bond behavior between CFRP sheet and natural calcareous stones

In this paper the effect of a long term immersion in water on bond durability is analyzed when FRPs (Fiber Reinforced Plastic) are externally applied to a masonry substrate. In the performed research a substrate made by natural calcareous stones, strengthened by CFRP (Carbon Fiber Reinforced Plastic) sheets has been analyzed. For a better comprehension of water effect on the adhesive bond between stone and CFRP, the same treatments were performed to the constituent materials, namely epoxy resins, CFRP sheets and stones. To this aim mechanical tests were carried out on stone, composite materials and epoxy resins before and after their immersion in water, evaluating the effects of this agent on the properties of the materials. The influence of the aging in water on the interface stone-reinforcement was analyzed in terms of bond strength, maximum bond stress, optimal bond length, slip-bond stress relationship and mode of failure. In addition the possibility of calibrating design relationships, taking into account the influence of environmental conditions is discussed. Detailed results on adhesives and composites aged in water have been reported in a previous paper while in the present work the significant decay of the mechanical properties of the stone is specifically investigated. With regard to the conditioning treatment a reduction of the bond strength has been observed (up to 26%) as well as a similar decrease of the maximum bond stress; in addition the aged specimens have shown a more fragile behavior. On the basis of the obtained results the empirical coefficient, reported in the available Italian Guidelines, to determine the FRP-masonry bond strength seems still effective when the system FRP-masonry is aged in water once the properties of the aged materials are considered in the provided relationships.     

Solvent additives for tuning the photovoltaic properties of polymer-fullerene solar cells

We use solvent additives as a simple method to tune the photovoltaic performance of poly-3-hexylthiophene (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojuncton solar cells. 1,2-dichlorobenzene (oDCB) was used as the reference solvent; chlorobenzene (CB) and 1,2,3,4-tetrahydronaphthalene (THN) were used as additives to influence film formation. An increase in the short circuit current and the power conversion efficiency of solar cells with blends cast from mixed solvents was observed. Blends prepared with THN, the highest boiling point solvent, resulted in the best device performance, while blends prepared with the pure reference solvent resulted in the lowest photocurrent. In-plane investigations of the morphology using transmission electron microscopy (TEM) revealed improved phase segregation for blends prepared with mixed solvents, and increased crystallinity in the P3HT phase is demonstrated using atomic force microscopy (AFM) coupled with Kelvin probe force microscopy (KPFM). Optical modeling reveals that the increase in the photocurrent is not due to changes in the optical properties of the blends. Electrical characterization reveals that the electron mobilities decrease slightly in blends cast from mixed solvents, corresponding to a decrease in the fill factor and an increase in P3HT crystallinity observed at the surface of the blend. The increase in the photovoltaic performance is discussed in terms of increased charge separation at the donor-acceptor interface due to increased ordering in the P3HT phase induced by the solvent additives.