2,076 research outputs found
Eziopatogenesi virale (HCV) nel determinismo dell'aborto ricorrente (ripetuto ed abituale)
Lâaborto 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 âsine causaâ).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 allâinfezione 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, lâinteressamento del prodotto del concepimento da parte dellâHCV potrebbe essere suggestivo di un significativo aspetto eziopatogenetico nel determinismo dellâaborto ricorrente
Wind tunnel simulation of atmospheric boundary layer flows
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
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
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
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
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 citizensâ 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 citizensâ habits. The future government should focus on adequate measures to improve health behaviours
Graphene-Polyurethane Coatings for Deformable Conductors and Electromagnetic Interference Shielding
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 sprayâcoating a nitrile substrate with a grapheneâelastomer solution. The electrical resistance of the coatings shows a decrease after thousands of bending cycles and a slight increase after repeated foldingâunfolding events. The deformable conductors double their electrical resistance at 12% strain and are washable without changing their electrical properties. The conductivityâstrain 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 ”mâ1 shielding in the 8â12 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
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.
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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