751 research outputs found
The Contribution of Air Logistics to the Development of Sicilian Economy
The role, played by globalization and the “just in time” supplying logic in present world economic scenario, implies that the opportunity of frequent, quick, safe and low-priced freight deliveries can be considered a key element for competitiveness. For these reasons, transportation systems, in the last years, have been characterized by the diffusion of intermodality and the “hub and spoke” distribution pattern. The phenomenon of organizing freight transport services according to a network and modal integration logic, has involved also the air transport field: to meet the new requirements of freight transportation market, in many cases, airline companies have become “global players”, expanding their network, in order to develop links among the main economic centres in the world. The goods moving by air can be defined as “top range products”; which means that only high value products (“market value” and “need value”) and the perishable ones (from a physical and economic point of view) demand air transport. The research described in this abstract aims at determining the contribution that can derive from air logistics to face a challenging problem: overcoming the peripheral role, in international trade, played by Sicily, which can boast high quality outputs in the agroindustrial sector and in the high technology one. The research consists of the following stages: 1. Analysing the sicilian freight transport system, with regard to the demand-supply relationship, paying particular attention to the commodity typologies mentioned above. 2. Identifying key actions for the air cargo services, in order to make Sicily improve in competitiveness, also taking into account the possibility of connecting Sicily with hub airports. 3. Determining the economic and social impact of the proposed solutions, considering different evolutionary scenarios and using also input-output analysis techniques.
Regular coffee: a magic bullet or a naked gun? Regular coffee but not espresso drinking is protective against fibrosis in NAFLD.
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Can partial splenectomy preserve humoral immunity in pediatric patients? Risks and benefts of partial splenectomy
Te spleen plays an important role in removing
normal and abnormal cells from
the blood and in providing an immunologic
response to encapsulated bacteria.
Surgical splenectomy provides efective
treatment for several pediatric disorders,
such as congenital and acquired hemolytic
anemias, abdominal traumas and immunological
and metabolic disorders, but it
is associated with an immediate and lifelong
risk of overwhelming infection. An
alternative to conventional splenectomy is
partial splenectomy, recommended especially
in children younger than 5 years of
age. Recommendations for the prevention
of overwhelming post-total splenectomy
infection include: Pneumococcal, Haemophilus
infuenzae type B and Meningococcal
immunizations, antimicrobial prophylaxis
and prompt antibiotic treatment of
acute febrile illness; conversely, there is no
clear evidence indicating which prevention
measures are to be performed in patients
undergoing partial splenectomy
Natural radioactivity content in groundwater of Mt. Etna's eastern flank and gamma background of surrounding rocks
Waters of Mt. Etna are the main source of drinking water for the local population and are also distributed in municipal supply systems to neighbouring areas. Radioactivity in underground waters and surrounding rocks from the eastern flank of Mt. Etna was investigated on the basis of 9 water and 8 rock samples from 12 localities altogether. Three samples were from water drainage galleries and six from water wells. All water intakes are used for consumption. Activity concentration of uranium isotopes234,238U, radium isotopes226,228Ra and radon222Rn were determined with the use different nuclear spectrometry techniques. The determination of uranium isotopes was carried out with the use of alpha spectrometry. The measurements of radium and radon activity concentration in water were performed with the use of a liquid scintillation technique. Additionally, rocks surrounding the intakes were examined with gamma spectrometry. All water samples showed uranium concentration above Minimum Detectable Activity (MDA), with the highest total uranium (234U +238U) activity concentration equal to 149.2±6 mBq/L. Conversely, all samples showed radium isotopes activity concentrations below MDA. Radon activity concentration was within the range from 2.91±0.36 to 21.21±1.10 Bq/L, hence these waters can be classified as low-radon waters. Gamma natural background of the rocks surrounding the water sampling sites was found on the same levels as other volcanic rocks of Italy
Structural and mutational analyses of the Leptospira interrogans virulence-related heme oxygenase provide insights into its catalytic mechanism
© 2017 Soldano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Heme oxygenase from Leptospira interrogans is an important virulence factor. During catalysis, redox equivalents are provided to this enzyme by the plastidic-type ferredoxin-NADP+ reductase also found in L. interrogans. This process may have evolved to aid this bacterial pathogen to obtain heme-iron from their host and enable successful colonization. Herein we report the crystal structure of the heme oxygenase-heme complex at 1.73 Å resolution. The structure reveals several distinctive features related to its function. A hydrogen bonded network of structural water molecules that extends from the catalytic site to the protein surface was cleared observed. A depression on the surface appears to be the H+ network entrance from the aqueous environment to the catalytic site for O2 activation, a key step in the heme oxygenase reaction. We have performed a mutational analysis of the F157, located at the above-mentioned depression. The mutant enzymes were unable to carry out the complete degradation of heme to biliverdin since the reaction was arrested at the verdoheme stage. We also observed that the stability of the oxyferrous complex, the efficiency of heme hydroxylation and the subsequent conversion to verdoheme was adversely affected. These findings underscore a long-range communication between the outer fringes of the hydrogen-bonded network of structural waters and the heme active site during catalysis. Finally, by analyzing the crystal structures of ferredoxin-NADP+ reductase and heme oxygenase, we propose a model for the productive association of these proteins
A Highly Stable Plastidic-Type Ferredoxin-NADP(H) Reductase in the Pathogenic Bacterium Leptospira interrogans
Leptospira interrogans is a bacterium that is capable of infecting animals and humans, and its infection causes leptospirosis with a range of symptoms from flu-like to severe illness and death. Despite being a bacteria, Leptospira interrogans contains a plastidic class ferredoxin-NADP(H) reductase (FNR) with high catalytic efficiency, at difference from the bacterial class FNRs. These flavoenzymes catalyze the electron transfer between NADP(H) and ferredoxins or flavodoxins. The inclusion of a plastidic FNR in Leptospira metabolism and in its parasitic life cycle is not currently understood. Bioinformatic analyses of the available genomic and proteins sequences showed that the presence of this enzyme in nonphotosynthetic bacteria is restricted to the Leptospira genus and that a [4Fe-4S] ferredoxin (LB107) encoded by the Leptospira genome may be the natural substrate of the enzyme. Leptospira FNR (LepFNR) displayed high diaphorase activity using artificial acceptors and functioned as a ferric reductase. LepFNR displayed cytochrome c reductase activity with the Leptospira LB107 ferredoxin with an optimum at pH 6.5. Structural stability analysis demonstrates that LepFNR is one of the most stable FNRs analyzed to date. The persistence of a native folded LepFNR structure was detected in up to 6 M urea, a condition in which the enzyme retains 38% activity. In silico analysis indicates that the high LepFNR stability might be due to robust interactions between the FAD and the NADP+ domains of the protein. The limited bacterial distribution of plastidic class FNRs and the biochemical and structural properties of LepFNR emphasize the uniqueness of this enzyme in the Leptospira metabolism. Our studies show that in L. interrogans a plastidic-type FNR exchanges electrons with a bacterial-type ferredoxin, process which has not been previously observed in nature
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