INFN muon tomography demonstrator Checchia, P.; Benettoni, M.; Bettella, G. ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
01/2019, Letnik:
377, Številka:
2137
Journal Article
Recenzirano
A short description of the muon tomography demonstrator at the INFN Laboratori Nazionali di Legnaro near Padua, Italy, is given and the principal achievements owing to the data collected at that ...experimental facility are presented. In particular, the feasibility studies for several applications based on the muon-tomographic technology, within national and European projects, are discussed. The experimental problems and the procedures used to improve the performance are underlined. In addition, new activities and the related detector optimization are illustrated.
This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.
Perfluorosulfonated ionomer (PFSI) dispersions in various solvents, usually mixtures of organic compounds and water, were used to prepare the membrane‐electrode system in polymer electrolyte membrane ...fuel cells (PEMFC), the aim being to increase performance by improving the triple contact of graphite (electron conducting material), Pt (hydrogen dissociation catalyst) and ionomeric membrane (proton conducting). When using PFSI dispersions in water‐organic solvent mixture, care must be taken not to poison the Pt catalyst through organic decomposition products, a consequence of the thermal treatment of the electrode‐polymer system bonded with PFSI dispersion. In the present study some procedures for preparing Nafion water dispersion, starting from a Nafion‐117 membrane, are described. The morphological characteristics of the prepared dispersions were compared with Nafion commercial dispersion (NCD). Moreover, membranes with a thickness of 5–20 μm were prepared and characterised, using both the obtained and the NCD dispersions. The obtained data showed that Nafion water dispersion, which can be used to prepare the membrane/electrode system, results in thin membranes that absorb more water than NCD membranes, and have equal and/or higher proton conduction than the NCD.
Colour vision in marsupials is a controversial issue, especially among the genus
Didelphis (Didelphidae, Didelphimorphia). While behavioural tests have diagnosed these animals as trichromats and ...electrophysiological studies have diagnosed them as monochromats, recent molecular genetics studies provide evidence for dichromatic colour vision, having found two classes of cone opsins in a species of this genus. This study examines the colour perception of a male and female white-eared opossum,
Didelphis albiventris, through a series of tasks involving a behavioural paradigm of discrimination learning. Both opossums succeeded in discriminating pairs of stimuli consisting of Munsell colour cards presented in random brightness values that are assumed to be easily discriminated by dichromats and trichromats (e.g. blues versus oranges). However, both subjects failed to discriminate between colours that are expected to be easily discriminated only by trichromats (e.g. greens versus oranges). The opossums were also unsuccessful in distinguishing a colour against itself (e.g. oranges versus oranges), demonstrating that discrimination was based only on visual cues. These results are consistent with recent predictions based on molecular genetics suggesting that the genus
Didelphis is routinely a dichromat.
MicroRNA (miRNA) is a recently discovered new class of small RNA molecules that have a significant role in regulating gene and protein expression. These small RNAs (∼22 nt) bind to 3′ untranslated ...regions (3′ UTRs) and induce degradation or repression of translation of their mRNA targets. Hundreds of miRNAs have been identified in various organisms and have been shown to play a significant role in development and normal cell functioning. Recently, a few studies have suggested that miRNAs may be an important regulators of circadian rhythmicity, providing a new dimension (posttranscriptional) of our understanding of biological clocks. Here, we describe the mechanisms of miRNA regulation, and recent studies attempting to identify clock miRNAs and their function in the circadian system.
To evaluate the use of two alternative modes of application (double-application and placement of a hydrophobic resin coat) compared with the manufacturers' directions on the microtensile bond ...strength (microTBS) of one-step, self-etch systems to enamel and dentin.
Resin composite buildups were bonded to the buccal and lingual ground enamel surfaces and occlusal dentin of third molars using the following adhesives: Xeno III (XE), GBond (GB), Adper Prompt L-Pop (AD) and Clearfil SE Bond (CSE) as the control. The adhesive systems were applied: (1) following the manufacturer's directions (MD), (2) with double-application (DA) or with (3) additional placement of a hydrophobic resin layer (HR) after following the manufacturer's directions. After storage in water (24 hours/37 degrees C), the bonded specimens were sectioned into sticks (0.8 mm2) that were tested until failure at a crosshead speed of 0.5 mm/minute. Data from each substrate were subjected to two-way ANOVA and Tukey's test (alpha = 0.05).
The interaction Adhesive vs. Application mode was statistically significant (p < 0.05) for both substrates. In dentin, XE and GB achieved high microTBS in the HR group (p < 0.05). For AD, the highest microTBS were observed in the DA group (p < 0.05). For enamel, similar microTBS was observed for XE and GB among the three modes of application, while the highest pTBS of AD was observed in the HR group.
The effects of using the double-application and placement of a hydrophobic resin coat on microtensile dentin-bond strength values seem to be effective; however, these techniques in enamel were adhesive-dependent.
A procedure to evaluate residual thermal stresses in polymer matrix composites is proposed, which takes into account the viscoelastic properties of the matrices. The viscoelasticity of the polymers ...was investigated by shear relaxation or dynamic mechanical tests. The influence of processing temperatures and cooling rates on the radial residual stresses acting around a carbon fibre was estimated both for thermoplastic and thermoset matrices. The importance of the radial stresses on the adhesion at the fibre—matrix interface was experimentally evaluated by fibre—matrix adhesion tests at different temperatures and after different cooling cycles.
The dependence of free volume on temperature has been monitored in some cross-linked polyurethanes, with different chain lengths, by using positron annihilation lifetime spectroscopy (PALS). The ...spectra were analysed in terms of continuous distributions in order to obtain the distribution of the longest component, τ3. The relative number and the mean size of free volume holes have been evaluated as a function of temperature: for T < Tg both the number and the volume of the holes increase; for T > Tg the number of the holes reaches a plateau while the hole volume increases significantly. The amplitude of the plateau widens with the cross-linking and the hydrogen bond interactions. At the end of the plateau the number of the holes increases more than the hole volume: the analysis of hole distribution indicates that the dispersion decreases with increasing temperature. The dispersion of the size of the nanovoids around their average values at the various temperatures has been estimated by a suitable computer code that uses a continuous sum of the decay curves with a log-normal distribution. For each sample a glass transition temperature has been estimated and compared with that obtained by d.s.c. The influence of cross-linking on the free volume is discussed.
Objective
Myofibrillar myopathies (MFMs) are morphologically distinct but genetically heterogeneous muscular dystrophies in which disintegration of Z disks and then of myofibrils is followed by ...ectopic accumulation of multiple proteins. Cardiomyopathy, neuropathy, and dominant inheritance are frequent associated features. Mutations in αB‐crystallin, desmin, myotilin, Zasp, or filamin‐C can cause MFMs and were detected in 32 of 85 patients of the Mayo MFM cohort. Bag3, another Z‐disk–associated protein, has antiapoptotic properties, and its targeted deletion in mice causes fulminant myopathy with early lethality. We therefore searched for mutations in BAG3 in 53 unrelated MFM patients.
Methods
We searched for mutations in BAG3 by direct sequencing. We analyzed structural changes in muscle by histochemistry, immunocytochemistry, and electron microscopy, examined mobility of the mutant Bag3 by nondenaturing electrophoresis, and searched for abnormal aggregation of the mutant protein in COS‐7 (SV‐40 transformed monkey kidney fibroblast‐7) cells.
Results
We identified a heterozygous p.Pro209Leu mutation in three patients. All presented in childhood, had progressive limb and axial muscle weakness, and experienced development of cardiomyopathy and severe respiratory insufficiency in their teens; two had rigid spines, and one a peripheral neuropathy. Electron microscopy showed disintegration of Z disks, extensive accumulation of granular debris and larger inclusions, and apoptosis of 8% of the nuclei. On nondenaturing electrophoresis of muscle extracts, the Bag3 complex migrated faster in patient than control extracts, and expression of FLAG‐labeled mutant and wild‐type Bag3 in COS cells showed abnormal aggregation of the mutant protein.
Interpretation
We conclude mutation in Bag3 defines a novel severe autosomal dominant childhood muscular dystrophy. Ann Neurol 2008
Beam characterization of a monolithic ΔE/E silicon device Agosteo, S.; Barcellan, L.; Borsato, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2015, Letnik:
779
Journal Article
Recenzirano
Odprti dostop
A full characterization of a ΔE/E monolithic silicon detector especially developed for microdosimetry was performed using monochromatic beams of α-particles and protons at the Italian National ...Laboratories of Legnaro at the CN van de Graaff accelerator. The investigation was performed in order to evaluate the limitations and the systematic effects affecting its use as a microdosimeter. The results can be extended to the standard use of these kind of devices as particle identifiers.
PDF
