We investigated metallothionein (MT) induction in the talitrid amphipod
Talitrus saltator
, a well-established biomonitor of trace metal contamination in the supralittoral environment, in response to ...laboratory exposure to Hg, Cd, or Cu for 3, 6, 24, and 48 h. Analyses were also carried out on animals collected in the wild from six localities along the Tuscan coast with different degrees of trace metal contamination. Animals exposed to Hg in the laboratory showed a strong dose-dependent increase of MT levels after 3 and 6 h; in the following hours (24 and 48 h), the MT concentrations reached control levels, possibly due to a general toxic effect of Hg. For the other metals, MT induction was observed in animals exposed to 10 ppm of Cd and 5 and 10 ppm of Cu. Therefore, despite the positive correlation between MT concentrations and trace metals in sandhoppers collected in the wild, the fast MT response observed in the laboratory suggests an inappropriate use of MT as biomarkers to assess trace metal pollution in coastal areas.
We report on the design, manufacturing and first characterisation of pad diodes, test structures and microstrip detectors processed with high resistivity magnetic Czochralski (MCz) p- and n-type Si. ...The pre-irradiation study on newly processed microstrip detectors and test structures show a good overall quality of the processed wafers. After irradiation with 24
GeV/
c protons up to 4×10
14
cm
-2 the characterisation of n-on-p and p-on-n MCz Si sensors with the
C–
V method show a decrease of the full depletion voltage and no space charge sign inversion. Microscopic characterisation has been performed to study the role of thermal donors in Czochralski Si. No evidence of thermal donor activation was observed in n-type MCz Si detectors if contact sintering was performed at a temperature lower than 380
°C and the final passivation oxide was omitted.
In this paper, the efficiency of lipid extraction from macrophytes (Chaetomorpha limmi. Ulva laetevirens, Valonia aegagrophyla, Gracilariopsis longissima, Ruppia cirrhosa) for the biodiesel ...production is evaluated using four different methods based on the Accelerated Solvent Extraction technique. Both wet and dried tissues are extracted and effects induced on lipid recovery by the pressure and the solvent mixture selection are evaluated. Results evidenced that better extraction performance is obtained using a polar/hydrophobic solvent mixture (1:1 v/v). Accelerate Solvent Extraction technique significantly improves the total amount of lipid extracted from macrophytes tissues even if average values are about 2% of the dry weight. Observed efficiencies are far from the productive standards required by the industrial process; nevertheless, lipid extraction from macrophytes could represent an interesting step of a much more complex biomass recycling process which could include, besides biodiesel, also, the production of other coimnercial materials as well as pigments and biosorbents.
The luminosity upgrade of the CERN Large Hadron Collider (SLHC) imposes severe requirements on the radiation hardness of the tracking systems. The CERN RD50 collaboration as well as the Italian INFN ...SMART project (fifth commission) are focused on the study of new radiation hard materials and devices in view of this upgrade. Preliminary studies on irradiated high resistivity n- and p-type magnetic Czochralski silicon are described in this paper. Electrical characterization and microscopic defect studies were performed on a wide set of diodes made with both n- and p-type float zone and magnetic Czochralski silicon irradiated up to a nominal fluence of 3×10
15
cm
−2 1
MeV equivalent neutrons. The annealing behavior was studied in detail and a first evaluation of the damage-related parameters is shown.
Due to their low depletion voltage, even after high particle fluences, improved tracking precision and momentum resolution, and reduced material budget, thin substrates are one of the possible ...choices to provide radiation hard detectors for future high energy physics experiments. In the framework of the CERN RD50 Collaboration, we have developed PIN diode detectors on membranes obtained by locally thinning the silicon substrate by means of TMAH etching from the wafer backside. Diodes of different shapes and sizes have been fabricated on 50-/spl mu/m and 100-/spl mu/m thick membranes and tested, showing a low leakage current (of 300 nA/cm/sup 3/) and a very low depletion voltage (in the order of 1 V for the 50 /spl mu/m membrane) before irradiation. Radiation damage tests have been performed with 58 MeV lithium (Li) ions up to the fluence of 10/sup 14/ Li/cm/sup 2/ in order to determine the depletion voltage and leakage current density increase after irradiation. Charge collection efficiency tests carried out with a /spl beta//sup -/ particle source have been performed on both nonirradiated devices and samples irradiated up to 1.8/spl times/10/sup 13/ Li/cm/sup 2/. Results reported here confirm the advantages of thinned diodes with respect to standard 300-/spl mu/m thick devices in terms of low depletion voltage and high charge collection efficiency.
In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin tuna samples collected in the spring of 2012 in Porto Scuso (South West Sardinia, Italy) ...and Villa Putzu (South East Sardinia, Italy) in order to assess the current levels of these two contaminants in fish muscle and the consequent risk to humans consuming said fish. Values of polychlorobiphenyls in bluefin tuna muscle vary between 0.155 and 1.403 mg/kg f.w.; the average of PCBs in tuna muscle is 0.732 mg/kg f.w. With regard to PCBs the presence of more elevated concentrations is confirmed in larger fish. The results regarding mercury in muscle show an average of 0.660 mg/kg f.w. and mercury values vary between 0.140 f.w. and 2.211 mg/kg f.w.; for mercury as well, the highest concentrations were found in the largest bluefin tuna. Six samples, 26% of total, contained more than 1 mg/kg f.w., which is the maximum level set by the European Commission (EC, Regulation n. 1881/2006) for this species. Mercury, in particular methylmercury, poses a risk to public health, therefore, taking into account the important nutritional contribution that tuna fish makes to the diet, it is advisable that women of childbearing age, pregnant and breastfeeding women as well as young children strictly limit their consumption of tuna from this area of the Mediterranean.
In the silicon tracker for the Compact Muon Solenoid experiment at the forthcoming Large Hadron Collider of CERN, each silicon sensor is connected to the front-end electronics by a pitch adapter, the ...structure of which consists of a fan of very thin chromium strips coated with a few microns aluminium deposition, on a glass support. The absence of contaminants in the depositions is of crucial importance for the electrical and mechanical reliability of the micro-bonding connections. The PIXE set-up of the Florence external micro-beam facility appeared to be suitable to analyse the metal deposition of an adapter, on which the micro-bonds had shown mechanical and electrical problems. Our measurements pointed out a significant copper contamination of the metal deposition on the faulty adapter, while no copper was detected in another one, which showed a correct behaviour at bonding. This suggests a possible role of Cu impurities in the encountered problems during micro-bonding.
The Oliveri-Tindari Lagoon, located in North-Eastern Sicily (Italy) and composed of six lakes, is subject to continuous environmental changes. An integrated study focusing on sediment features and ...levels of contamination was carried out for three of the six lakes, which are of ancient origin: Verde, Mergolo della Tonnara and Marinello. A high primary production (26.89 μg l
−1
) was detected at Lake Verde; texture classification showed a typical grain size in the sediments of all lakes; the study of macronutrients highlighted 17.08 of total carbon in sediments from Lake Mergolo della Tonnara; toxic elements were detected at higher concentrations in the sediments of Lake Marinello in comparison to the others, while arsenic was found in high concentrations in all the samples tested, especially in Lake Verde, with a mean value of 17.25 mg kg
−1
dry weight (d.w.). All the organic contaminants, except 4, 4′-dichlorodiphenyldichloroethylene, were below the detection limits in the sediments. Minimal microbiological contamination was found in both water and sediment samples. In the latter, we isolated several bacterial strains thriving in the presence of arsenic, which play a role in the biogeochemical cycle of arsenic. These preliminary results, obtained for the first time using a multidisciplinary approach, provide general information about the Oliveri-Tindari Lagoon area.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We investigated the effect of amending soil with olive mill by-products by examining soil characteristics and nitrifying and heterotrophic bacteria content, in comparison with non-amended soils. The ...effect of the amendment on organic carbon content was also evidenced. No differences were revealed in terms of heterotrophic bacteria, whereas the addition of olive mill by-products increased nitrifying bacteria content in soils with the addition of organic mixtures containing olive mill wastes. Two nitrifying bacterial strains were isolated from amended soils and given the names ISAFOM-B3 and ISAFOM-C2; 16S rDNA gene sequencing assigned them to the genus Arthrobacter and to the α-Proteobacteria subclass, respectively. A higher nitrate content was revealed in enrichment cultures prepared with amended soils when compared to non-amended ones. Nitrifying bacteria were imaged by fluorescent in situ hybridisation. A high total organic carbon content was detected in the amended soils, with an improvement of the humification indexes. This study suggests a positive effect of the addition of olive mill by-products on soils.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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