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Film ultrasottili di ionomeri preparati mediante la tecnica di Langmuir-Blodgett per applicazione in sensori
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Composite films of poly-(ester-sulphonated) and poly-(3-methylthiophene) for ion-exchange voltammetry in acetonitrile solutions
Full text linkDetermination of inorganic arsenic with ensembles of nanoelectrodes: from batch to flow analysis
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Seasonal cycling of mercury and methyl mercury in the Venice Lagoon (Italy)
No full textFrom 1950s to 1980s, the Venice Lagoon was extensively contaminated with mercury (Hg) from chlor-alkali discharges and
other sources, prompting researchers to assess the distribution of contamination in sediments and biota. Since the lagoon is
shallow and bordered by extensive wetlands, contains high sulfate from the sea, and high nutrient loading from agricultural
runoff and urban sewage, it is expected to act as a vigorous microbiological incubator for Hg methylation. Here we report
seasonal findings (2001–2003) for total Hg and monomethyl mercury (CH3Hg) in water column, rivers, precipitation,
suspended matter, sediments, and biota samples collected using ultra-clean sampling techniques. Aqueous total Hg ranged from
about 5–10 pM at the Lido entrance to the Adriatic, to 25–100 pM within the main body of the northern lagoon. A sudden drop
in Hg concentration is observed when crossing the Canale dei Petroli,the major deep-water shipping canal which roughly
bisects the lagoon) in a southward direction. The less contaminated southern reaches of the lagoon were not studied as
intensively, but were found to contain only 10–20 pM total Hg. Up to 250–1000 pM were observed in the industrially impacted
areas and urban canals. Most Hg was from re-suspended sediments, as levels are strongly correlated with total suspended solids
(TSS) in this very shallow (b1 m) lagoon. Dissolved Hg concentrations were narrowly constrained to the range of
approximately 3–15 pM. Monomethyl mercury ranged from about 0.1–2 pM in unfiltered samples and 0.03–1 pM in the
dissolved phase. Surface (0–3 cm) sediments varied from about 2.5–12.5 nmol g1, with 0.1–0.3% of that as CH3Hg.
Monomethyl mercury levels were about three times higher during the spring and summer, compared to winter. The lagoon
appears to be moderately, but extensively contaminated by Hg, showing concentrations of both total Hg and CH3Hg similar to
those reported in other urban harbors, but spread over hundreds of km2. The impact of the historic direct chlor-alkali discharges
to the lagoon is diffused throughout the system by an array of re-suspension pathways, but may ultimately be mitigated by rapid
tidal flushing
Conical nanopore membranes: solvent shaping of nanopores
Full text linkWe have undertaken a systematic investigation of the influence of ethanol on
the shape of conical pores produced by the track-etch technique in
poly(ethylene terephthalate) films. We have found that the cone angle of the
conical nanopore generated is dependent on the amount of ethanol present in
an alkaline etching solution. By varying the percentage of ethanol in the etch
solution, precise control over the geometry of the conical nanopore and
nanomaterials templated within these pores can be attained. We prove this by
plating gold nanocones within the various conical nanopores prepared,
dissolving the membrane to liberate the nanocones, and imaging the
nanocones using scanning electron microscopy. The results of these
investigations are reported here
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