760 research outputs found
Gamma-ray observations of Supernova Remnants with Fermi -LAT data
After 8 years of data taking, the Large Area Telescope (LAT) onboard the Fermi satellite has shown an excellent capability to detect and observe Supernova Remnants (SNRs) from few hundred MeV up to few hundred GeV. It provides crucial information on physical processes happening at the source, involving both accelerated leptons and hadrons, in order to understand the mechanisms responsible for the acceleration of primary Cosmic Rays. We interpreted the multiwavelength Spectral Energy Distribution (SED) of a sample of different types of SNRs, which have been observed by the Fermi-LAT. We show how the environment in which the supernova shock is propagating affects the interpretation of its SED. We evaluated the spectral features of the accelerated particle spectra and estimated the acceleration efficiency, as well as the maximum energy of accelerated particles
Galactic science with Fermi -LAT
High energy γ-rays reveal extreme, non-thermal processes in the Universe. The Fermi Large Area Telescope (LAT) has been exploring the γ-ray sky for almost eight years, enabling the observation of many powerful events happening in our Galaxy. The wide energy range and field of view make the LAT a unique instrument to monitor the sky and study both powerful transient events and longterm phenomena. We present a review of the latest results obtained by the FermiLAT observation of Galactic object
Direct femtosecond laser fabrication of superhydrophobic aluminum alloy surfaces with anti-icing properties
Ice formation is a serious issue in many fields, from energy to aerospace, compromising the devices' efficiency and security. Superhydrophobicity has been demonstrated to be correlated to the anti-icing properties of surfaces. However, fabricating surfaces with robust water repellence properties also at subzero temperature is still a great challenge. In this work, femtosecond laser (fs-laser) texturing is exploited to produce superhydrophobic surfaces with anti-icing properties on Al2024, an aluminum alloy of great interest in cold environments, in particular for aircraft production. Our textured substrates present self-cleaning properties and robust water repellency at subzero temperatures. Moreover, outstanding anti-icing properties are achieved on the textured surfaces at-20 °C, with water droplets bouncing off the surface before freezing
Minimally invasive (flapless) crown lengthening by erbium: YAG laser in aesthetic zone
Crown lengthening is a surgical procedure aimed at exposure of a larger tooth surface by gingivectomy alone or with cortical bone remodelling for aesthetic purposes in the anterior zone of the maxilla or for reconstruction of teeth affected by subgingival caries. We report two cases of crown lengthening in the anterior maxilla for aesthetic purposes by gingival and bone re-contouring performed by erbium-doped yttrium aluminium garnet (erbium:YAG) laser. As highlighted in this report, the erbium:YAG laser-assisted crown lengthening is less invasive and also leads to faster clinical outcomes in contrast to the conventional surgical technique by scalpel incision, flap elevation and osteoplastic
A minimally invasive technique for short spiral implant insertion with contextual crestal sinus lifting in the atrophic maxilla: A preliminary report
The most recently reported techniques for the rehabilitation of the atrophic posterior maxilla are increasingly less invasive, as they are generally oriented to avoid sinus floor elevation with lateral access. The authors describe a mini-invasive surgical technique for short spiral implant insertion for the prosthetic rehabilitation of the atrophic posterior maxilla, which could be considered a combination of several previously described techniques based on the under-preparation of the implant site to improve fixture primary stability and crestal approach to the sinus floor elevation without heterologous bone graft. Eighty short spiral implants were inserted in the molar area of the maxilla in patients with 4.5–6 mm of alveolar bone, measured on pre-operative computed tomography. The surgical technique involved careful drilling for the preparation of implant sites at differentiated depths, allowing bone dislocation in the apical direction, traumatic crestal sinus membrane elevation, and insertion of an implant (with spiral morphology) longer than pre-operative measurements. Prostheses were all single crowns. In all cases, a spiral implant 2–4 mm longer than the residual bone was placed. Only two implants were lost due to peri-implantitis but subsequently replaced and followed-up. Bone loss values around the implants after three months (at the re-opening) ranged from 0 to 0.6 mm, (median value: 0.1 mm), while after two years, the same values ranged from 0.4 to 1.3 mm (median value: 0.7 mm). Clinical post-operative complications did not occur. After ten years, no implant has been lost. Overall, the described protocol seems to show good results in terms of predictability and patient compliance
Cosmic-ray interactions with the Sun
The solar disk is a bright gamma-ray source in the sky. The interactions of cosmic rays with the solar atmosphere produce secondary particles which can reach the Earth. In this work we present a comprehensive calculation of the yields of secondary particles such as gamma-rays, electrons, positrons, neutrons and neutrinos, performed with the FLUKA code. We also estimate the intensity at the Sun and the fluxes at the Earth of these secondary particles by folding their yields with the intensities of cosmic rays impinging on the solar surface. The results are sensitive to the assumptions on the magnetic field near the Sun and to the cosmic-ray transport in the magnetic field in the inner solar system
Identification of a dna methylation episignature in the 22q11.2 deletion syndrome
The 22q11.2 deletion syndrome (22q11.2DS) is the most common genomic disorder in humans and is the result of a recurrent 1.5 to 2.5 Mb deletion, encompassing approximately 20–40 genes, respectively. The clinical presentation of the typical deletion includes: Velocardiofacial, Di George, Opitz G/BBB and Conotruncalanomaly face syndromes. Atypical deletions (proximal, distal or nested) are rare and characterized mainly by normal phenotype or mild intellectual disability and variable clinical features. The pathogenetic mechanisms underlying this disorder are not completely understood. Because the 22q11.2 region harbours genes coding for transcriptional factors and chromatin remodelers, in this study, we performed analysis of genome‐wide DNA methylation of peripheral blood from 49 patients with 22q11.2DS using the Illumina Infinium Methylation EPIC bead chip arrays. This cohort comprises 43 typical, 2 proximal and 4 distal deletions. We demonstrated the evidence of a unique and highly specific episignature in all typical and proximal 22q11.2DS. The sensitivity and specificity of this signature was further confirmed by comparing it to over 1500 patients with other neurodevelopmental disorders with known episignatures. Mapping the 22q11.2DS DNA methylation episignature provides both novel insights into the molecular pathogenesis of this disorder and an effective tool in the molecular diagnosis of 22q11.2DS
The Efficacy of a New AMCOP® Elastodontic Protocol for Orthodontic Interceptive Treatment: A Case Series and Literature Overview
Background: Elastodontics is a specific interceptive orthodontic treatment that uses removable elastomeric appliances. They are functional appliances that produce neuromuscular, orthopedic and dental effects. Thus, these devices are useful in the developmental age, when skeletal structures are characterized by important plasticity and adaptation capacity, allowing to remove factors responsible for malocclusions. Elastomeric devices are generally well tolerated by patients requiring simple collaboration and management. This work can be useful to update all orthodontists already adopting these appliances or for those who want to approach them for the first time. This study aimed to describe four cases treated with new elastomeric devices called AMCOP Bio-Activators and to provide an overview of elastodontics, its evolution, indications and limits. Methods: A total of four clinical cases were presented after a treatment period of 16–20 months to evaluate the clinical and radiological effects of the elastodontic therapy. Results: The effectiveness of Bio-Activators on clinical cases was evidenced with a significant improvement in skeletal and dentoalveolar relationship, and malocclusion correction in a limited treatment period (16–20 months). Conclusions: The Bio-Activators showed clinical effectiveness to achieve therapeutic targets according to a low impact on the patient’s compliance
Supernova Remnants with Fermi Large Area Telescope
The Large Area Telescope (LAT), on-board the Fermi satellite, proved to be, after 8 years of data taking, an excellent instrument to detect and observe Supernova Remnants (SNRs) in a range of energies running from few hundred MeV up to few hundred GeV. It provides essential information on physical processes that occur at the source, involving both accelerated leptons and hadrons, in order to understand the mechanisms responsible for the primary Cosmic Ray (CR) acceleration. We show the latest results in the observation of Galactic SNRs by Fermi-LAT
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