2,037 research outputs found

    Eziopatogenesi virale (HCV) nel determinismo dell'aborto ricorrente (ripetuto ed abituale)

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    L’aborto ricorrente puĂČ essere definito come la presenza di due (aborto ripetuto) o piĂč aborti (aborto abituale) di tipo consecutivo. Diverse condizioni possono essere individuate come fattori eziopatogenetici di aborto ricorrente; tuttavia, circa la metĂ  dei casi rimane ancora senza causa apparente (aborto “sine causa”).Nel nostro studio sono state inserite 350 donne in stato di gravidanza con storia clinica di aborto ricorrente, le quali sono state studiate in riferimento all’infezione da HCV. Delle 350 donne esaminate, 65 (18,6%) sono risultate positive per tale infezione. In particolare, 53 (81%) hanno presentato una positivitĂ  della viremia compresa tra 105 e 106 copie/ml; mentre, le restanti 12 (19%) hanno evidenziato una positivitĂ  della viremia > 106 copie/ml. Pertanto, l’interessamento del prodotto del concepimento da parte dell’HCV potrebbe essere suggestivo di un significativo aspetto eziopatogenetico nel determinismo dell’aborto ricorrente

    Wind tunnel simulation of atmospheric boundary layer flows

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    The present work shows how thick boundary layers can be produced in a short wind tunnel with a view to simulate atmospheric flows. Several types of thickening devices are analysed. The experimental assessment of the devices was conducted by considering integral properties of the flow and the spectra: skin-friction, mean velocity profiles in inner and outer co-ordinates and longitudinal turbulence. Designs based on screens, elliptic wedge generators, and cylindrical rod generators are analysed. The paper describes in detail the experimental arrangement, including the features of the wind tunnel and of the instrumentation. The results are compared with experimental data published by other authors and with naturally developed flows.IndisponĂ­vel

    ATLAS RPC Quality Assurance results at INFN Lecce

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    The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. Since July 2004, about 270 RPC units has been certified at INFN Lecce site and delivered to CERN, for being integrated in the final muon station of the ATLAS barrel region. We show the key RPC characteristics which qualify the performance of this detector technology as muon trigger chamber in the harsh LHC enviroments. These are dark current, chamber efficiency, noise rate, gas volume tomography, and gas leakage.Comment: Comments: 6 pages, 1 table, 9 figures Proceedings of XXV Physics in Collision-Prague, Czech Republic, 6-9 July 200

    Self-Powered Edible Defrosting Sensor

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    Improper freezing of food causes food waste and negatively impacts the environment. In this work, we propose a device that can detect defrosting events by coupling a temperature-activated galvanic cell with an ionochromic cell, which is activated by the release of ions during current flow. Both the components of the sensor are fabricated through simple and low-energy-consuming procedures from edible materials. The galvanic cell operates with an aqueous electrolyte solution, producing current only at temperatures above the freezing point of the solution. The ionochromic cell exploits the current generated during the defrosting to release tin ions, which form complexes with natural dyes, causing the color change. Therefore, this sensor provides information about defrosting events. The temperature at which the sensor reacts can be tuned between 0 and -50 °C. The device can thus be flexibly used in the supply chain: as a sensor, it can measure the length of exposure to above-the-threshold temperatures, while as a detector, it can provide a signal that there was exposure to above-the-threshold temperatures. Such a device can ensure that frozen food is handled correctly and is safe for consumption. As a sensor, it could be used by the workers in the supply chain, while as a detector, it could be useful for end consumers, ensuring that the food was properly frozen during the whole supply chain

    Multifunctional Biocomposites Based on Polyhydroxyalkanoate and Graphene/Carbon Nanofiber Hybrids for Electrical and Thermal Applications

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    Most polymers are long-lasting and produced from monomers derived from fossil fuel sources. Bio-based and/or biodegradable plastics have been proposed as a sustainable alternative. Amongst those available, polyhydroxyalkanoate (PHA) shows great potential across a large variety of applications but is currently limited to packaging, cosmetics and tissue engineering due to its relatively poor physical properties. An expansion of its uses can be accomplished by developing nanocomposites where PHAs are used as the polymer matrix. Herein, a PHA biopolyester was melt blended with graphene nanoplatelets (GNPs) or with a 1:1 hybrid mixture of GNPs and carbon nanofibers (CNFs). The resulting nanocomposites exhibited enhanced thermal stability while their Young's modulus roughly doubled compared to pure PHA. The hybrid nanocomposites percolated electrically at lower nanofiller loadings compared to the GNP-PHA system. The electrical conductivity at 15 wt.% loading was ~ 6 times higher than the GNP-based sample. As a result, the electromagnetic interference shielding performance of the hybrid material was around 50% better than the pure GNPs nanocomposites, exhibiting shielding effectiveness above 20 dB, which is the threshold for common commercial applications. The thermal conductivity increased significantly for both types of bio-nanocomposites and reached values around 5 W K-1 m-1 with the hybrid-based material displaying the best performance. Considering the solvent-free and industrially compatible production method, the proposed multifunctional materials are promising to expand the range of application of PHAs and increase the environmental sustainability of the plastic and plastic electronics industry.Comment: 26 page

    Effects of quarantine on Physical Activity prevalence in Italian Adults: a pilot study

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    Background: COVID-19 is a respiratory disease that caused a global pandemic status in March 2020. Due to its fast diffusion, many governments adopted forced solutions including social restrictions, which could negatively affect citizens’ habits as physical activity. Our study aimed to investigate how and why the physical activity prevalence varied from the period before the quarantine up to the period after it, and understand what citizens thought of physical inactivity COVID-19 related to and whether they were satisfied with physical activity promotion during the lockdown. Methods: A new questionnaire was created and administered online. A sample of 749 interviews (female = 552 (73.7%), male = 197 (26.3%)) was collected and analysed. Results: The prevalence of people who were older than 50 years reduced both during and after the lockdown (P < 0.05) and the most common reason for which they have quitted physical activity practice was related to psychological problems (lockdown = 64.57%; post-lockdown = 62.17%). In addition, youngers seemed to be more sensitive than elders to unhealthy consequences generated by forced isolation (P < 0.05), and they believed that children/adolescents and older adults practised an insufficient amount of physical activity and/or sport, which could negatively impact public health. Conclusions: Although many strategies were implemented during the lockdown to promote regular physical activity practice, several results suggested that quarantine negatively affected citizens’ habits. The future government should focus on adequate measures to improve health behaviours

    Graphene-Polyurethane Coatings for Deformable Conductors and Electromagnetic Interference Shielding

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    Electrically conductive, polymeric materials that maintain their conductivity even when under significant mechanical deformation are needed for actuator electrodes, conformable electromagnetic shielding, stretchable tactile sensors, and flexible energy storage. The challenge for these materials is that the percolated, electrically conductive networks tend to separate even at low strains, leading to significant piezoresistance. Herein, deformable conductors are fabricated by spray‐coating a nitrile substrate with a graphene–elastomer solution. The electrical resistance of the coatings shows a decrease after thousands of bending cycles and a slight increase after repeated folding‐unfolding events. The deformable conductors double their electrical resistance at 12% strain and are washable without changing their electrical properties. The conductivity–strain behavior is modeled by considering the nanofiller separation upon deformation. To boost the conductivity at higher strains, the production process is adapted by stretching the nitrile substrate before spraying, after which it is released. This adaption meant that the electrical resistance doubles at 25% strain. The electrical resistance is found sufficiently low to give a 1.9 dB ”m−1 shielding in the 8–12 GHz electromagnetic band. The physical and electrical properties, including the electro magnetic screening, of the flexible conductors, are found to deteriorate upon cycling but can be recovered through reheating the coating

    ATLAS RPC Cosmic Ray Teststand at INFN Lecce

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    We describe the design and functionality of the cosmic ray teststand built at INFN Lecce for ATLAS RPC quality control assurance.Comment: XXIV Physics in Collisions Conference (PIC04), Boston, USA, June 2004, 3 pages, LaTex, 2 eps figures. MONP0

    The behaviour of nuclear domains in the course of apoptosis.

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    none9Programmed cell death is activated, by different stimuli and in many cell types, to regulate cell population balance during tissue proliferation and embryogenesis. Its initial event seems to be, in most cases, the activation of a Ca2+-dependent endonuclease, causing DNA cleavage into nucleosomic fragments. Its morphological expression is characterized by deep nuclear changes, consisting of typical cap-shaped chromatin marginations, followed by nuclear fragmentation and final formation of numerous micronuclei. Cytoplasmic damage appears in a very late stage of the process and the greatest part of the phenomenon appears to take place despite good preservation of the plasma membrane and organellar component. In the present study we analyzed apoptosis in camptothecin-treated HL60 leukaemia cells, and in freshly isolated mouse thymocytes treated with dexamethasone. The process was first quantified and time monitored by flow cytometry. Subsequently the specimens were processed for morphological examination in order to investigate the behaviour of the different nuclear domains. To follow DNA and RNA localization, we utilized osmium ammine and DNase-colloidal gold cytochemical reactions. The concentration of most DNA in the cap-shaped structures was demonstrated by these reactions. Confocal microscopy of cells processed by in situ nick-translation suggested that DNA was firstly cleaved and subsequently condensed in cup-shaped structures. Despite the strong nuclear modifications, nucleoli could be clearly recognized until the late apoptotic stages.openFALCIERI E; ZAMAI L; SANTI S; CINTI C; GOBBI P.; BOSCO D; CATALDI A; BETTS C; VITALE MFalcieri, Elisabetta; Zamai, Loris; Santi, S; Cinti, C; Gobbi, Pietro; Bosco, D; Cataldi, A; Betts, C; Vitale, M
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