102,237 research outputs found
Structural and Electrical Characterizations of Polymer-Supported Graphene Fabricated by Graphite Nanoplatelets
No full textTackling Information Asymmetry in Networks: A New Entropy-Based Ranking Index
No full textInformation is a valuable asset in socio-economic systems, a significant part of which is entailed into the network of connections between agents. The different interlinkages patterns that agents establish may, in fact, lead to asymmetries in the knowledge of the network structure; since this entails a different ability of quantifying relevant, systemic properties (e.g. the risk of contagion in a network of liabilities), agents capable of providing a better estimation of (otherwise) inaccessible network properties, ultimately have a competitive advantage. In this paper, we address the issue of quantifying the information asymmetry of nodes: to this aim, we define a novel index—InfoRank—intended to rank nodes according to their information content. In order to do so, each node ego-network is enforced as a constraint of an entropy-maximization problem and the subsequent uncertainty reduction is used to quantify the node-specific accessible information. We, then, test the performance of our ranking procedure in terms of reconstruction accuracy and show that it outperforms other centrality measures in identifying the “most informative” nodes. Finally, we discuss the socio-economic implications of network information asymmetry
Microstructural Characterization of Thin Films Obtained by Laser Irradiation.
No full textThin films obtained by direct pulsed excimer laser irradiation
and by laser reactive ablation were characterized by scanning
electron microscopy, cross sectional transmission electron
microscopy and grazing angle X-ray diffraction. The results
obtained were interpreted in function of the deposition
parameters such as substrate temperature, pressure of the
ambient atmosphere, number of laser pulses and laser fluence
Extraction efficiency of different microplastic polymers from deep-sea sediments and their quantitative relevance
No full textAn increasing number of methods for extracting microplastic particles from marine sediments have been published but without evaluating the extraction efficiency. Furthermore, while most of the procedures developed have been applied to sandy sediments from shallow water habitats, specific and standardized procedures for deep-water sediments (> 200 meters deep) are limited. In this study, we describe a specific protocol for extracting microplastics (2- 1000 μm) from deep-sea sediments and for quantifying and identifying them. We also assessed its extraction efficiency, which resulted in a high recovery (on average ca. 60%, and up to 80%) particularly, for polyethylene, polypropylene, and polystyrene. This method can be applied to all fine-grained/muddy sediments and allows the extraction of even the smallest fraction of microplastics (<20 μm), which are expected to have the most severe effects on marine biodiversity and ecosystem functioning and ultimately also have implications for human health
Microstructural characterization of titanium carbide films deposited by laser reactive ablation.
No full text
Structure evolution of EV31 Mg alloy
No full textStructure modifications and precipitation hardening of EV31 Mg alloy have been monitored by calorimetric measurements (DSC), TEM
observations and positron annihilation spectroscopy (PAS). At the early stages of precipitation DSC measurements andTEMobservations evidenced
the formation of a phase, while the presence of an intermediate is supported by positron data. Overageing is correlated to the formation of
an incoherent 1 phase, which transforms in situ into the equilibrium precipitate
Modified TiO2 particles differentially affect human skin fibroblasts exposed to UVA light.
No full textFree Radic Biol Med. 2010 Aug 1;49(3):408-15. Epub 2010 May 5.
Modified TiO(2) particles differentially affect human skin fibroblasts exposed to UVA light.
Tiano L, Armeni T, Venditti E, Barucca G, Mincarelli L, Damiani E.
Source
Dipartimento di Biochimica, Biologia e Genetica, , Università Politecnica delle Marche, I-60131 Ancona, Italy.
Abstract
Numerous sunscreens contain titanium dioxide (TiO(2)) because of its ability to reflect, scatter, and absorb UV radiation, thus preventing sunlight-related skin disorders. Since TiO(2) is well known to generate reactive oxygen species (ROS) under photoexcitation, it is chemically modified when used in sunscreens. In the present study, five modified TiO(2) particles, specifically developed and marketed for sunscreens, were tested using different in vitro models, including cultured human skin fibroblasts (HuDe), to investigate their possible photocatalytic effects following UVA exposure. The results obtained show that the type of modification and crystal form determine their ability to (a) induce photobleaching of the DPPH radical, (b) photodegrade deoxyribose, (c) reduce cell viability, (d) increase/decrease DNA damage, and (e) increase/decrease intracellular ROS. This research concludes that some modified TiO(2) particles still retain photocatalytic activity under the experimental conditions employed, especially those in which the anatase crystal form of TiO(2) is present. The penetration of TiO(2) nanosized particles into the viable epidermis of skin is still under debate; thus, the results presented here contribute to gaining further knowledge on the potential effects of TiO(2) particles at the cellular level, in the worst possible case that they do penetrate.
Copyright 2010 Elsevier Inc. All rights reserved.
PMID: 20450973 [PubMed - indexed for MEDLINE
The karyology of the Antarctic whelk, Neobuccinum eatoni (Mollusca, Neogastropoda)
No full textKaryotype, location of the nucleolar organizer regions (NORs) and heterochromatin presence and composition were studied in the Antarctic whelk Neobuccinum eatoni. The karyotype exhibits 2n=68 chromosomes with 10 pairs of metacentrics, 14 pairs of meta-submetacentrics, six pairs of submeta-subtelocentrics, and one pair of subtelo-telocentrics. Silver and CMA(3)/ methyl green staining and rDNA FISH evidenced telomeric NORs on the long arm of a pair of medium-sized submetacentrics. Staining with AT-specific fluorochromes evidenced telomeric bands on nearly all chromosomes and interstitial Q bands on two pairs of presumably subtelocentric chromosomes. The karyological evolution of N. eatoni seems to be characterized by a generalized neogastropod karyotype associated with a genome size increase following the accumulation of heterochromatin containing AT-rich repetitive DNA; according to some authors the latter could be related to the modulation of morphological and functional parameters of ecological significance
- …
