0000000000382955
AUTHOR
G. La Manna
Hydrogenation of light hydrocarbons on palladium: theoretical study of the local surface arrangements
Abstract Quantum mechanical calculations at HF, MP2 and DFT levels were used to rationalise the surface effects of the hydrocarbon lateral interactions occurring on single planar metal surfaces or on different adjacent surfaces during the hydrogenation on palladium catalyst. The different values of electronic charge, found in the different atoms of palladium clusters, were suggested as a possible explanation of the non-homogeneous behaviour already inferred for catalyst surface sites having non-isotropic local arrangement.
Study of lecithin reverse micelles by FT-IR spectroscopy
FT-IR spectra of water/lecithin/deuterated cyclohexane microemulsions as a function of water/lecithin molar ratio R (R=[water]/[lecithin]) at various lecithin volume fractions (φ) have been recorded. After elimination of the spectral contributions due to the deuterated cyclohexane and normalization, the band parameters of the CO and PO4 vibrational modes due to lecithin have been found dependent only upon R. This behaviour has been interpreted in terms of a progressive structural modification of the water/lecithin interface superimposed to the progressive hydration of CO and PO4 groups. Moreover, no correlation between the CO and PO4 band parameters and the formation of gel-like micellar so…
Behavioural strategy of common bottlenose dolphins (Tursiops truncatus) in response to different kinds of boats in the waters of Lampedusa Island (Italy)
Owing to the increase of boat-traffic in the ocean many studies have been conducted to determine the response of bottlenose dolphin (Tursiops truncatus) to this kind of disturbance. This species is affected by boats in various ways and the response depends on the behavioural state of the dolphin but also on the kind of vessel. This study aimed to determine the effect of motorboats and trawlers on dolphins' presence, permanence in the area and whistle parameters in Lampedusa waters (Italy). Sampling was carried out between May and December 2006 and between July and September 2009, using experimental passive acoustic monitoring systems (PAM); a total of 300 h of recordings and 3000 whistles w…
Position paper on liver and kidney diseases from the Italian Association for the Study of Liver (AISF), in collaboration with the Italian Society of Nephrology (SIN)
Abstract Liver and kidney are strictly connected in a reciprocal manner, in both the physiological and pathological condition. The Italian Association for the Study of Liver, in collaboration with the Italian Society of Nephrology, with this position paper aims to provide an up-to-date overview on the principal relationships between these two important organs. A panel of well-recognized international expert hepatologists and nephrologists identified five relevant topics: 1) The diagnosis of kidney damage in patients with chronic liver disease; 2) Acute kidney injury in liver cirrhosis; 3) Association between chronic liver disease and chronic kidney disease; 4) Kidney damage according to dif…
Structural and dynamical investigation of gelation containing water-in-oil microemulsions
The gelatin (Bloom 300)/water/AOT/n-heptane system has been investigated at fixed water/AOT molar ratioR (R=31.1) as a function of the gelatin content. Several experimental techniques (densitometry, refractometry, conductometry, rheology, dielectrometry, ultrasonics, hypersonics) have been used to investigate the role played by the gelatin molecule in the observed sol-gel transition above a critical gelatin content. The results appear consistent with the hypothesis of a rigid network of gelatin-water rods coated by surfactant molecules coexisting with gelatin-free AOT reversed micelles at the gelation point.
Monitoring the habitat use of common Bottlenose Dolphins (Tursiops truncatus) using passive acoustics in a Mediterranean marine protected area
The Mediterranean Tursiops truncatus subpopulation has been classified as Vulnerable on the IUCN Red List because of its decline. This species in coastal areas is exposed to a wide variety of threats: directed kills, bycatch, reduced prey availability caused by environmental degradation and overfishing, habitat degradation including disturbances from boat traffic and noise. Despite the increase in boat traffic in the Mediterranean Sea, the effect on T. truncatus’ habitat use has been studied in little detail and few data have been published. This study represents the first attempt to characterise spatial and temporal habitat use by T. truncatus and its relation to boat traffic in the Isole …
Dielectric properties of solutions of antimony (III) halides in methanol
The complex permittivities obtained by time domain reflectometry (TDR) measurements in the frequency range 0.1–15 GHz are reported for solutions of SbF3, SbCl3 and SbBr3 in methanol at 25°C. By increasing the concentration of the solutes, a marked increase of the main relaxation time and of the static permittivity of methanol is observed. These effects have been attributed to the ability of antimony (III) halides to strengthen the hydrogen bonding in methanol and to promote the shift of the dynamic equilibria among the various populations of hydrogen bonded methanol aggregates toward those characterized by a parallel orientation of neighboring dipoles. A second relaxation, occurring at low …
Calorimetric investigation of the interaction between a macromolecular prodrug of diflunisal and human platelets
The thermal effect due to the interaction between human platelets and α,β poly(N-hydroxy-ethyl)-DL-aspartamide (PHEA) or the PHEA-Diflunisal conjugate was measured by the calorimetric technique at 25°C. The experimental data confirm that PHEA is a biocompatible macromolecule and that its conjugate influences the physiological activity of human platelets.
Calorimetric investigation on the formation of palladium nanoparticles in water/AOT/n-heptane microemulsions
The formation enthalpy of palladium nanoparticles in water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)n-heptane microemulsions as a function of the waterAOT molar ratio (R = [water][AOT]) was measured by a calorimetric technique. The results indicate that at R < 10 the energetic state of the palladium nanoparticles compartmentalized within the reversed AOT micelles is signficantly different from that in bulk water. Effects due to the small size of the palladium nanoparticles and to interactions between nanoparticles and the waterAOT interface are discussed.
Structural Investigation of Water/Lecithin/Cyclohexane Microemulsions by FT-IR Spectroscopy
Abstract FT-IR spectra of water/lecithin/deuterated cyclohexane microemulsions as a function of water/lecithin molar ratio R ( R = [water]/[lecithin]) at various volume fractions ( O ) of the micellar phase have been recorded at 25°C. After elimination of the small spectral contributions due to deuterated cyclohexane and normalization, the shape of the C–H stretching band due to lecithin has been found dependent upon R and O whereas that of the O–H stretching band has been found dependent only upon R . The change in shape of the C–H band was interpreted in terms of a modification of the lecithin alkyl chain packing order. The analysis of the O–H band provides evidence that the hydroxylic gr…
Boat traffic in Lampedusa waters (Strait of Sicily, Mediterranean Sea) and its relation to the coastal distribution of common bottlenose dolphin (Tursiops truncatus).
The volume of boat traffic and its potential connection to the coastal distribution of the common bottlenose dolphin (Tursiops truncatus) was evaluated off Lampedusa Island (Strait of Sicily). From July to September 2006 daily surveys were carried out at eight sites along the coast, three times a day, to assess the number, type, and size of boats moving, fishing, or stationed in Lampedusa waters. The study area was divided into four geographic areas: northwest, northeast, southwest, and southeast. Data were analyzed to determine the difference in the number of boats among the areas, sampling months, and times of day. The presence of dolphins was monitored by standardized land-based observat…
Fragmentations and reactions of some isotopically labelled dimethyl methyl phosphono and trimethyl phosphoro thiolates and thionates studied by electrospray ionisation ion trap mass spectrometry
In this paper, studies on electrospray ionisation ion trap mass spectrometry of organophosphates are extended to a series of dimethyl methylphosphono and trimethyl phosphoro thionates and thiolates and some deuterated isotopomers. Of particular, interest is the comparison of the collision-induced fragmentation of ions from these compounds with those of the non-sulphur containing analogues reported previously. The thiono and thiolo isomeric structures of the sulphur containing ions analogous to I and II (see below) have very similar energies and undergo a ready interconversion. In the case of the phosphono compounds, the electronic structure calculations show that the methyl migration implic…
Population analysis of pair densities. A study on cyclic systems
Abstract Pair population analysis seems a reliable method for evaluating atomic valency states and bond orders from the MO wavefunction of molecular systems. A test on some cyclic organic systems was performed. The results confirm the capability of the method to provide a correct description of the molecules in terms of simple VB approach.
Dielectric properties of water/lecithin/cyclohexane gels
Dielectric relaxation measurements in the frequency range 0.1–15 GHz have been carried out on water/lecithin/cyclohexane gels using a time domain reflectometry method (TDR). Dielectric dispersions describable in terms of a power law typical of percolated systems, but with exponents significantly different from those characterizing statically or dynamically percolated systems are observed. The dielectric dispersions, attributed to water and/or lecithin head group rotational motions, indicate that these motions are characterized by a wide spectrum of relaxation times.
The detrimental consequences for seagrass of ineffective marine park management related to boat anchoring.
Posidonia oceanica (L.) Delile meadows are recognized as priority habitat for conservation by the EU Habitats Directive. The La Maddalena Archipelago National Park (Mediterranean Sea) P. oceanica meadow. , the dominant coastal habitat of the area, is mostly threatened by boat anchoring. 12. years after the establishment of mooring fields and anchoring restrictions, a study was conducted to measure their effectiveness on the conservation of seagrass and the mitigation of anchoring damage. We found that: (i) the condition of P. oceanica was disturbed, both in the mooring fields and in control locations; (ii) mooring fields and anchoring restrictions did not show to be an efficient system for …
Electrostatic contribution to the interaction of α, β poly (N-hydroxyethyl)-DL-aspartamide with sodium dodecylsulfate micelles
The enthalpic effect due to the interaction between α, β poly(N-hydroxyethyl)-DL-aspartamide (PHEA) and sodium dodecylsulfate (SDS) in aqueous solutions as a function of the surfactant concentration was measured by the calorimetric technique at various NaCl concentrations. A marked influence of the added electrolyte on the PHEA-SDS interaction was observed. An analysis of the experimental enthalpies allows to estimate the electrostatic and the hydrophobic contributions to the enthalpy of interaction between PHEA and SDS micelles. The results were rationalized in terms of effects due to the screening of the charges residing on PHEA and SDS micelles.
Behavioral response of brown meagre (Sciaena umbra) to boat noise
Underwater man-made noise is recognized as a major global pollutant in the 21st Century, and its reduction has been included in national and international regulations. Despite the fact that many studies have pointed out the ecological impact of noise on marine organisms, few studies have investigated - in a field context - the behavioral response to boat noise in fish. In the present study we measure how Sciaena umbra reacts to boat noise. We found that boat noise: i) increased duration of flight reactions and number of individuals performing them, ii) increased the frequency of hiding behaviors, and iii) did not elicit a change in fish activity level and sound emission. Flights and hiding …
Predicting common bottlenose dolphin habitat preference to dynamically adapt management measures from a Marine Spatial Planning perspective
Abstract At the European Level, SACs (Special Areas of Conservation) are considered among the most reliable tools for increasing the efficiency of protective actions and to identify species vulnerability hotspots across spatial scales. Nevertheless, SACs may fail in their scope when design and management are not dynamically adapted to meet ecological principles. Knowledge of the spatial distribution of relevant key species, such as common bottlenose dolphin (Tursiops truncatus), is crucial in order to achieve the objective of the Habitat Directive (92/43/EEC), and is a fundamental step in the process of Marine Spatial Planning. From this perspective, new data and analysis are required to pr…
Calorimetric investigation of water/lecithin/cyclohexane microemulsions
The enthalpies of dilution of water/lecithin/cyclohexane microemulsion-gels at variousR values (R=[water]/[lecithin]) and molar enthalpies of solution of water in lecithin/cyclohexane at a fixed lecithin concentration were determined calorimetrically at 25°C. Through a description of the process of dilution of water/lecithin/cyclohexane microemulsion-gels as one involving mainly the scission of lecithin reversed micelles in to smaller ones, the concentration dependence of the enthalpy was rationalized. Surprisingly, in order to account for the dilution enthalpies, it was not necessary to hypothesize a thermal effect arising from the breakage of the micellar network present in the micremulsi…
Study of AOT-stabilized microemulsions of formamide and n-methylformamide dispersed in n-heptane
Abstract A wide investigation of some physicochemical properties (density, viscosity, conductance, IR spectra, permittivity) of AOT-stabilized dispersions of formamide and n -methylformamide in n -heptane has been performed. The experimental data are consistent with the hypothesis that these highly hydrophilic substances are encapsulated within AOT reversed micelles and that this structure is maintained for both systems well above the volume fraction of the dispersed phase where a percolative transition occurs. In addition, the observed properties of these microemulsions reveal the pivotal role of intermicellar attractive interactions in driving the percolative transition. A marked modifica…