Low-frequency modes in the Raman spectrum of sp-sp2 nanostructured carbon

A novel form of amorphous carbon with sp-sp2 hybridization has been recently produced by supersonic cluster beam deposition showing the presence in the film of both polyynic and cumulenic species [L. Ravagnan et al. Phys. Rev. Lett. 98, 216103 (2007)]. Here we present a in situ Raman characterization of the low frequency vibrational region (400-800 cm-1) of sp-sp2 films at different temperatures. We report the presence of two peaks at 450 cm-1 and 720 cm-1. The lower frequency peak shows an evolution with the variation of the sp content and it can be attributed, with the support of density functional theory (DFT) simulations, to bending modes of sp linear structures. The peak at 720 cm-1 does not vary with the sp content and it can be attributed to a feature in the vibrational density of states activated by the disorder of the sp2 phase.Comment: 15 pages, 5 figures, 1 tabl

Development and validation of a cell based model of insulin resistance and investigation into the intracellular molecular defects induced by diabetes and obesity

A reduction in the sensitivity of tissue to insulin is termed insulin resistance. In the clinic this condition is associated with obesity and inactivity and often leads to the development of type 2 diabetes. A major focus of antidiabetic therapy is to develop novel interventions to alleviate insulin resistance. However, the initial physiological and molecular defects in the development of insulin resistance remain elusive. This knowledge would greatly aid the development of novel and more effective insulin sensitisers.In an effort to improve the understanding of insulin resistance this thesis establishes that culturing liver cells in sera from obese diabetic patients reduces the ability of insulin to repress the key gluconeogenic gene, phosphoenolpyruvatecarboxykinase (PEPCK). Cells cultured in serum from obese diabetic human subjects exhibited defective PEPCK mRNA suppression by 0.1 and 0.5 nM insulin compared to cells cultured in control serum (p<0.0001), representing a shift to the right of the insulin dose response curve. Classification of human sera, using the response of the cell model following incubation with the sera, was actually more reliable than any single clinical biomarker at establishing whether the serum came from a volunteer with insulin resistance. This suggests that the cell model could be developed as a means to classify insulin resistance in the human population more reliably than simply measuring fasting glucose.The system was developed and optimised as a cell based humanised model of insulin resistance to aid the search for a biomarker for the development of obesity related insulin resistance. However, there was no linear relationship between any single biomarker and the resistance causing ability of the sera. Interestingly, cells cultured chronically in the presence of fetal calf serum supplemented with 5 pM insulin (the average increase in insulin between cases and controls) also exhibited reduced suppression of PEPCK by 0.1 and 0.5 nM insulin compared to controls (p=0.03 and 0.01 respectively). This has major implications for the understanding of how insulin resistance may develop. It suggests that minor increases in insulin release from beta cells, or minor loss of insulin clearance in the liver that elevate plasma insulin are potential initiating mechanisms for insulin resistance (at least in liver). Of course there may be many ways to initiate insulin resistance in vivo, but establishing the relative importance of the beta cell and the liver as an initial site for the development of insulin resistance is clearly important for effective intervention. Subsequent to the generation of insulin resistance in culture I could not detect significant differences in the response of the major post-receptor insulin signalling pathway components, between cells cultured under standard conditions and those cultured chronically in 5 pM insulin. Therefore the mechanism underlying this reduced insulin action on PEPCK gene transcription remains unclear.I then went on to develop reporter cell lines both for use in the study of the regulation of hepatic gene transcription by insulin and also as a potential screen for effective insulin sensitisers. Unfortunately the reporter cell lines did not turn out to be useful as hoped, as the reporter genes did not develop insulin resistance in response to chronic exposure to 5 pM insulin. In addition there were some differences between the reporter genes and endogenous genes in response to specific signalling inhibitors. This questions their suitability for the purposes proposed.Finally, I examined the signalling connections between the class of insulin sensitiser known as biguanides, and DNA repair mechanisms, as an initial characterisation of molecular links between diabetes and cancer. I established that inhibiting the DNA repair enzyme ATM reduces the phosphorylation of the biguanide target, AMPK in response to these drugs. However, although inhibition of ATM reduced biguanide suppression of G6Pase it had little effect on the regulation of PEPCK gene transcription by the drugs. This is consistent with AMPK not being the key mediator of biguanide regulation of PEPCK gene transcription and suggests that biguanide regulation of G6Pase and PEPCK gene transcription is mediated through distinct signalling pathways.In summary, I have developed a cell based model of insulin resistance that relies on factor (s) present in serum from humans with diabesity, and thus should be useful as a screen for more effective insulin sensitisers targeted at the population that donates the serum. It is likely that one of the factors responsible for generation of resistance is insulin itself as chronic exposure to low levels (albeit higher than background), of insulin reduces insulin sensitivity of the cells. The molecular details of the development of insulin resistance remain elusive as none of the major signalling pathways appear to be defective in the cells that have developed reduced insulin regulation of PEPCK. However, the data raise the intriguing possibility that chronic but mild hyperinsulinemia due to defective insulin secretion or clearance is an initial step in the development of insulin resistance. Hence, reducing insulin secretion (as opposed to current strategies of inducing insulin secretion) may be a more effective therapy for prevention of the development of insulin resistance. Finally, elements of the DNA repair pathways such as ATM may impinge on pathways that affect insulin sensitivity, including the biguanide target AMPK.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

In Situ Treatment of Contaminated Water Environments: The Experiment of the Arsenale Vecchio, Venice Lagoon, Italy

We report on the results of an experiment of in situ bioremediation by forced aeration, carried out in the Arsenale Vecchio shipyard dock basin of the Venice Lagoon, Italy. The experimental area is characterized by its limited size and reduced boat traffic. The forced aeration technique chosen for the oxygenation of the highly polluted bottom sediments and of the water column above does not obstruct harbor activities and is unique due to its innovative use of a system of porous pipes laid on the bottom sediments. The general recovery of the polluted shipyard dock basin resulted in the documented return of small fish to the area as an indication of a less polluted environment. Most important the bioremediation of the water body above the bottom sediment favours, with time, the formation of a clean natural sediment capping over the bottom contaminated sediments. Post-experiment control after fifteen months of aeration with no extra oxygen added, shows the presence of clean light grey sediments with no foul septic smell, deposited over the polluted bottom sediments. The experiment has indicated that oxygenation by porous pipe forced aeration could represent a cost effective and environmentally feasible way for the recovery of shallow marine and fresh water systems, in situations where other techniques may not be economically and/or environmentally feasible

The central role of Italy in the spatial spread of USUTU virus in Europe

USUTU virus (USUV) is an arbovirus maintained in the environment through a bird-mosquito enzootic cycle. Previous surveillance plans highlighted the endemicity of USUV in North-eastern Italy. In this work, we sequenced 138 new USUV full genomes from mosquito pools (Culex pipiens) and wild birds collected in North-eastern Italy and we investigated the evolutionary processes (phylogenetic analysis, selection pressure and evolutionary time-scale analysis) and spatial spread of USUV strains circulating in the European context and in Italy, with a particular focus on North-eastern Italy. Our results confirmed the circulation of viruses belonging to four different lineages in Italy (EU1, EU2, EU3 and EU4), with the newly sequenced viruses from the North-eastern regions, Veneto and Friuli Venezia Giulia, belonging to the EU2 lineage and clustering into two different sub-lineages, EU2-A and EU2-B. Specific mutations characterize each European lineage and geographic location seem to have shaped their phylogenetic structure. By investigating the spatial spread in Europe, we were able to show that Italy acted mainly as donor of USUV to neighbouring countries. At a national level, we identified two geographical clusters mainly circulating in Northern and North-western Italy, spreading both northward and southward. Our analyses provide important information on the spatial and evolutionary dynamics of USUTU virus that can help to improve surveillance plans and control strategies for this virus of increasing concern for human health

FM22 (Frozen Mitochondria bioassay): an animal alternative bioassay for toxicity measures for water soluble samples.

Several methods have been proposed, using responses of whole organisms. The problem, however, is not only strictly scientific, but also involves cost, resources and time. For example, assay with organisms require expensive testing facilities and long operational times are necessary for toxicity measurements. In order to evaluate potential compound toxicity (acute and sub-chronic), we standardized a bioassay using mitochondria of beef hearth, and their applicability and sensitivity was verified. In respect to other based on mitochondria tests, this bioassay (called FM22) showed unquestionable advantages: i) to freeze mitochondria at -22 °C instead of the classical -80 °C, ii) to perform a very big quantity of biological test using always the same mitochondria pool (avoiding differences from age, sex, or health status depending on different organisms); iii) to identify quickly a tested compounds IC50, easily comparable. FM22 end point is the inhibition of mitochondrial respiratory chain and this event is quantified by oxygen monitoring. The oxygen consumption was measured by a Clark electrode that was interfaced to a PC to collect test analysis data (1200 in 20 Macro, identifiedmin run). A piecewise regression, through an Excel the break point in the oxygen consumption and calculated the toxicity. Blank tests were carried out to verify the oxygen consumption linear fitting. Toxicity tests were performed using pure/mix organic and inorganic compounds, elutriates from sea- and fresh-water sediment, sewage, dissolved burned compound sub-products. The FM22 test was a good predictor of toxicity for water and soluble samples; the bioassay is easy, low cost and rapid, then usable for routine tests or like a part of a battery of ecotoxicological tests

Poly(methyl methacrylate) - Palladium clusters nanocomposite formation by supersonic cluster beam deposition: a method for microstructured metallization of polymer surfaces

Nanocomposite films were fabricated by supersonic cluster beam deposition (SCBD) of palladium clusters on Poly(methyl methacrylate) (PMMA) surfaces. The evolution of the electrical conductance with cluster coverage and microscopy analysis show that Pd cluster are implanted in the polymer and form a continuous layer extending for several tens of nanometers beneath the polymer surface. This allows the deposition, using stencil masks, of cluster-assembled Pd microstructures on PMMA showing a remarkably high adhesion compared to metallic films obtained by thermal evaporation. These results suggest that SCBD is a promising tool for the fabrication of metallic microstructures on flexible polymeric substrates.Comment: 11 pages, 3 figure

Collaborative digital and wide format printing : methods and considerations for the artist and master printer

This thesis investigates the collaborative production of fine art digital prints for artists,a process which is used by many contemporary practitioners including Richard Hamilton and Damien Hirst. Digital print as a fine art process has emerged over the last twenty years, and as yet, there is no in depth evidence on the collaborative endeavour and production process which is central to the digital Master Printer’s role. The investigation first establishes the historical context and significance of the Master and Printer in traditional printmaking, and the more recent development of the digital print studio and the digital print pioneers of the 1990s. A series of seven artists’ case studies in the context of the collaborative digital print studio are then offered to demonstrate the working process. The analysis of these proposes a best practice model for Master Printers working with contemporary artists to produce high quality, fine art, wide format inkjet digital prints. The study also compares production methods at the cutting-edge digital facility of the Rijksakademie in The Netherlands, to assess the validity of the practices proposed through a facility closest to the study’s research base at the CFPR’s digital studio. The comparative study also explored the expanding digital production process and the role of the Master Printer. Evolving production processes are also considered in this study as a response to the advancement of digital print technology alongside a practical exploration of what actually constitutes a digital print in this rapidly expanding field of fine art printmaking. This study aims to reveal the inner workings of the digital collaborative process between the artist and Master Printer, and appraise the digital Master Printer’s role. It offers a set of best practice methods for the digital Master Printer developed from this research. The study also considers how the digital print, and the digital print studio may evolve in line with current and future developments in new technologies.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Establishment of a national network of cetacean monitoring within the marine strategy

CONISMA, CNR and CIRCE, involved Italian research units (RUs) working on cetaceans to joina National Network answering the Marine Strategy Framework Directive (MSFD) requirements by sharing monitoring data. Data obtained during the 2016 monitoring campaigns by 13 RUs are presented here

core level spectroscopy of free titanium clusters in supersonic beams

Synchrotron radiation x-ray absorption spectroscopy (XAS) is one of the most powerful techniques to interrogate the local electronic structure and chemical status of bulk and nanostructured systems. The application of this technique to the study of size effects in free clusters of transition metal atoms would advance substantially fundamental knowledge of nano-objects and the tailoring of their magnetic and catalytic properties. To date core level spectroscopy of free transition metal clusters has been out of reach due to the lack of a cluster source able to produce clusters in the gas phase with a density suitable for synchrotron radiation sources. Here we demonstrate the XAS characterization of free titanium clusters in a supersonic molecular beam. We use a high-intensity cluster beam source coupled to a synchrotron beamline to investigate the size dependence of core level excitation of Tin clusters in the mass range 1

First report in italy of the exotic mosquito species Aedes (Finlaya) koreicus, a potential vector of arboviruses and filariae

BACKGROUND: In the Veneto region (north-eastern Italy) an entomological surveillance system has been implemented since the introduction of the Asian tiger mosquito (Aedes albopictus) in 1991. During the routine monitoring activity in a tiger mosquito-free area, an unexpected mosquito was noticed, which clearly did not belong to the recorded Italian fauna. FINDINGS: At the end of May 2011, twelve larvae and pupae were collected in a small village in Belluno province (Veneto region) from a single manhole. Ten adults reared in the laboratory were morphologically and genetically identified as Aedes (Finlaya) koreicus (Edwards, 1917), a species native to Southeast Asia. The subsequent investigations carried out in the following months in the same village provided evidence that this species had become established locally. Entomological and epidemiological investigations are currently ongoing in the surrounding area, to verify the eventual extension of the species outside the village and to trace back the route of entry into Italy. CONCLUSIONS: This is the first report in Italy of the introduction of the exotic mosquito Ae. koreicus. This species has been shown experimentally to be competent in the transmission of the Japanese encephalitis virus and of the dog heartworm Dirofilaria immitis and is considered a potential vector of other arboviruses. Thus, the establishment of this species may increase the current risk or pose new potential threats, for human and animal health. This finding considerably complicates the entomological monitoring of the Asian tiger mosquito Ae. albopictus in Italy and stresses the importance of implementing the entomological surveillance for the early detection of and the rapid response against invasive mosquito species