Institute for Scientific Interchange Foundation ISI

Sant'Ambrogio di Torino, Italy

Institute for Scientific Interchange Foundation ISI

Sant'Ambrogio di Torino, Italy
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Bono R.,University of Turin | Romanazzi V.,University of Turin | Munnia A.,ISPO Cancer Prevention and Research Institute | Piro S.,ISPO Cancer Prevention and Research Institute | And 10 more authors.
Chemical Research in Toxicology | Year: 2010

Formaldehyde is an ubiquitous pollutant to which humans are exposed. Pathologists can experience high formaldehyde exposure levels. Formaldehyde-among other properties-induce oxidative stress and free radicals, which react with DNA and lipids, leading to oxidative damage and lipid peroxidation, respectively. We measured the levels of air-formaldehyde exposure in a group of Italian pathologists and controls. We analyzed the effect of formaldehyde exposure on leukocyte malondialdehyde-deoxyguanosine adducts (M1-dG), a biomarker of oxidative stress and lipid peroxidation. We studied the relationship between air-formaldehyde and M1-dG adducts. Air-formaldehyde levels were measured by personal air samplers. M1-dG adducts were analyzed by a 32P-postlabeling assay. Reduction room pathologists were significantly exposed to air-formaldehyde with respect to controls and to the pathologists working in other laboratory areas (p < 0.001). A significant difference for M1-dG adducts between exposed pathologists and controls was found (p = 0.045). The effect becomes stronger when the evaluation of air-formaldehyde exposure was based on personal samplers (p = 0.018). Increased M1dG adduct levels were only found in individuals exposed to air-formaldehyde concentrations higher than 66 μg/m3. When the exposed workers and controls were subgrouped according to smoking, M1-dG tended to increase in all of the subjects, but a significant association between M1-dG and air-formaldehyde was only found in nonsmokers (p = 0.009). Air-formaldehyde played a role positive but not significant (r = 0.355, p = 0.075, Pearson correlation) in the formation of M1-dG, only in nonsmokers. Working in the reduction rooms and exposure to air-formaldehyde concentrations higher than 66 μg/m3 are associated with increased levels of M 1-dG adducts. © 2010 American Chemical Society.


Giorda P.,Institute for Scientific Interchange Foundation ISI | Allegra M.,Institute for Scientific Interchange Foundation ISI | Allegra M.,University of Turin | Allegra M.,National Institute of Nuclear Physics, Italy | Paris M.G.A.,University of Milan
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

In recent years the paradigm based on entanglement as the unique measure of quantum correlations has been challenged by the rise of new correlation concepts, such as quantum discord, able to reveal quantum correlations that are present in separable states. It is in general difficult to compute quantum discord, because it involves a minimization over all possible local measurements in a bipartition. In the realm of continuous-variable (CV) systems, a Gaussian version of quantum discord has been put forward upon restricting to Gaussian measurements. It is natural to ask whether non-Gaussian measurements can lead to a stronger minimization than Gaussian ones. Here we focus on two relevant classes of two-mode Gaussian states: squeezed thermal states and mixed thermal states, and allow for a range of experimentally feasible non-Gaussian measurements, comparing the results with the case of Gaussian measurements. We provide evidence that Gaussian measurements are optimal for Gaussian states. © 2012 American Physical Society.


Allegra M.,Institute for Scientific Interchange Foundation ISI | Allegra M.,University of Turin | Giorda P.,Institute for Scientific Interchange Foundation ISI
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

We address the role of topology in the energy transport process that occurs in networks of photosynthetic complexes. We take inspiration from light-harvesting networks present in purple bacteria and simulate an incoherent dissipative energy transport process on more general and abstract networks, considering both regular structures (Cayley trees and hyperbranched fractals) and randomly generated ones. We focus on the the two primary light-harvesting complexes of purple bacteria, i.e., the LH1 and LH2, and we use network-theoretical centrality measures in order to select different LH1 arrangements. We show that different choices cause significant differences in the transport efficiencies, and that for regular networks, centrality measures allow us to identify arrangements that ensure transport efficiencies which are better than those obtained with a random disposition of the complexes. The optimal arrangements strongly depend on the dissipative nature of the dynamics and on the topological properties of the networks considered, and depending on the latter, they are achieved by using global versus local centrality measures. For randomly generated networks, a random arrangement of the complexes already provides efficient transport, and this suggests the process is strong with respect to limited amount of control in the structure design and to the disorder inherent in the construction of randomly assembled structures. Finally, we compare the networks considered with the real biological networks and find that the latter have in general better performances, due to their higher connectivity, but the former with optimal arrangements can mimic the real networks' behavior for a specific range of transport parameters. These results show that the use of network-theoretical concepts can be crucial for the characterization and design of efficient artificial energy transport networks. © 2012 American Physical Society.


PubMed | Institute for Scientific Interchange Foundation ISI
Type: Journal Article | Journal: Physical review. E, Statistical, nonlinear, and soft matter physics | Year: 2012

We address the role of topology in the energy transport process that occurs in networks of photosynthetic complexes. We take inspiration from light-harvesting networks present in purple bacteria and simulate an incoherent dissipative energy transport process on more general and abstract networks, considering both regular structures (Cayley trees and hyperbranched fractals) and randomly generated ones. We focus on the the two primary light-harvesting complexes of purple bacteria, i.e., the LH1 and LH2, and we use network-theoretical centrality measures in order to select different LH1 arrangements. We show that different choices cause significant differences in the transport efficiencies, and that for regular networks, centrality measures allow us to identify arrangements that ensure transport efficiencies which are better than those obtained with a random disposition of the complexes. The optimal arrangements strongly depend on the dissipative nature of the dynamics and on the topological properties of the networks considered, and depending on the latter, they are achieved by using global versus local centrality measures. For randomly generated networks, a random arrangement of the complexes already provides efficient transport, and this suggests the process is strong with respect to limited amount of control in the structure design and to the disorder inherent in the construction of randomly assembled structures. Finally, we compare the networks considered with the real biological networks and find that the latter have in general better performances, due to their higher connectivity, but the former with optimal arrangements can mimic the real networks behavior for a specific range of transport parameters. These results show that the use of network-theoretical concepts can be crucial for the characterization and design of efficient artificial energy transport networks.

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