Study of GaAs detectors characteristics for medical imaging

In this work we present the results of a systematic study about SI GaAs detectors as a function of substrate and contact type, geometry and thickness. This study has been stimulated from the interest in using GaAs as a detector for medical imaging applications. GaAs detectors have been produced using crystals grown with different techniques and changing both the thickness (in the range 200 μm-1 mm) and the contacts type and geometry. We have measured the current-voltage characteristics and, using radioactive sources (109Cd, 20 keV photons, 241Am, 60 keV photons, 99mTc, 140 keV photons), we have studied the performance of our detectors in terms of charge collection efficiency and energy resolution as a function of the bias voltage. Besides we have also studied the electrical and spectroscopic properties of GaAs detectors with different types and concentrations of the dopants in the substrate. So we have found the optimal doping type and concentration to have the best spectroscopic performances and the higher breakdown voltage. Simulation programs made with Monte Carlo methods have been developed to describe the electric field distribution and the transport of charge carriers toward the electrodes in GaAs detectors. In these simulations we have considered the presence of deep energy levels in the bandgap, the thickness, the bias voltage and the charge deposition in the crystal after photon interaction

Covid-19 And Rheumatic Autoimmune Systemic Diseases: Role of Pre-Existing Lung Involvement and Ongoing Treatments

The Covid-19 pandemic may have a deleterious impact on patients with autoimmune systemic diseases (ASD) due to their deep immune-system alterations

COVID-19 Severity in Multiple Sclerosis: Putting Data Into Context

Background and objectives: It is unclear how multiple sclerosis (MS) affects the severity of COVID-19. The aim of this study is to compare COVID-19-related outcomes collected in an Italian cohort of patients with MS with the outcomes expected in the age- and sex-matched Italian population. Methods: Hospitalization, intensive care unit (ICU) admission, and death after COVID-19 diagnosis of 1,362 patients with MS were compared with the age- and sex-matched Italian population in a retrospective observational case-cohort study with population-based control. The observed vs the expected events were compared in the whole MS cohort and in different subgroups (higher risk: Expanded Disability Status Scale [EDSS] score > 3 or at least 1 comorbidity, lower risk: EDSS score ≤ 3 and no comorbidities) by the χ2 test, and the risk excess was quantified by risk ratios (RRs). Results: The risk of severe events was about twice the risk in the age- and sex-matched Italian population: RR = 2.12 for hospitalization (p < 0.001), RR = 2.19 for ICU admission (p < 0.001), and RR = 2.43 for death (p < 0.001). The excess of risk was confined to the higher-risk group (n = 553). In lower-risk patients (n = 809), the rate of events was close to that of the Italian age- and sex-matched population (RR = 1.12 for hospitalization, RR = 1.52 for ICU admission, and RR = 1.19 for death). In the lower-risk group, an increased hospitalization risk was detected in patients on anti-CD20 (RR = 3.03, p = 0.005), whereas a decrease was detected in patients on interferon (0 observed vs 4 expected events, p = 0.04). Discussion: Overall, the MS cohort had a risk of severe events that is twice the risk than the age- and sex-matched Italian population. This excess of risk is mainly explained by the EDSS score and comorbidities, whereas a residual increase of hospitalization risk was observed in patients on anti-CD20 therapies and a decrease in people on interferon

DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France

We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon

Measured model, theoretical model and represented model: the so called “ Arch of Drusus” in Rome

"The Arch of Drusus is a complex building, stratified over time. It isn’t possible to advance only one hypothesis about its origin, but its several transformations may be given some interpretations. The difficulty lies in the coexistence of two structures, typologically and. chronologically different, in a single monument: an original structure which can be related to a commemorative travertine arch sheathed in marble, dating back to the Imperial Age, which probably had three fornices and a later structure reused in the III century as an aqueduct arch and monumentalized again with the application of decorated architectural elements on the southern façade. In order to provide a graphic description as much accurate as possible from the metric-dimensional point of view and as much detailed as possible in all the elements which form the building, a new survey methodology has been tested. It uses different kinds of systems – instrumental, topographic and GPS, photogrammetric and direct traditional – which complement each other, in order to render a three-dimensional computerized reference model. The analysis process of the monument, made from what emerged from the archaeological analysis, thanks to the carrying out of different navigable models, has been developed making, in the early stage, a represented model subsequently detailed on the basis of the incongruities detected in the survey. -

Neuroticism and Self-Confidence of Physically Challenged Viz. Hearing Impaired and Speech Impaired Secondary School Students of Kashmir Division

As per the directive principles of constitution, education should be fair without the any regional or communal bias and should make justice with every individual more than ever for all marginalized groups including visually, hearing, orthopedically and speech impaired. This would permit community participation in education at the basic level and would introduce deep-seated change, leading to the empowerment of learners with Special Educational Needs such as visually, hearing, orthopedically and speech impaired. Until the 1970s, the policy encouraged isolation because the majority of educators thought that children with physical, sensory, or intellectual disabilities were so dissimilar and unusual that they could not take part in the activities of a common school (Advani, 2002). The majority of disabled population is deprived and experience difficulties in accessing essential health as well as rehabilitation services. This costs immobility, isolation, dependency, inequality, often premature death and enlarged poverty. According to the national census (2001) there are 21.9 million disabled people in India– that constitutes about 2.13 per cent of the total population - 1.03 per cent are visually impaired, 0.59 per cent ’orthopedically impaired 0.16 per cent speech impaired, 0.12 per cent ‘hearing’ impaired, and 0.22 per cent ‘mentally’ retard of the total national population. Hearing impairment refers to a defect in or injure to the sensory mechanism. The injury or defect might occur in various parts of the ear. It leads to hearing impairment or loss of hearing. A person may become deaf or hard of hearing depending upon the nature of impairment and the degree of hearing loss. Hearing impaired are those in whom the sense of hearing is non-functional for ordinary function of living. These people do not have capacity to distinguish sound at all even with improved vocalizations. The various sensory defective subjects included in this class will be those having hearing loss of more than 70 decibels (Graham Bell’s Scale) in the better ear (profound) loss of hearing in both ears (ministry of social welfare 1987). A hearing impairment is a hearing loss that prevents a person from totally receiving sounds from side to side the ear. As such sensory hearing defect leads to various other social and psychological problems. These hearing defective persons are prescribed to use hearing aids in order to overcome the various problems. In persistent hearing loss, the someone can not to discriminate any sounds. There are four types of sensory hearing defects such as Conductive hearing defect, neural defect, varied hearing defect and innermost hearing defect

CKD and cardiac damage.

<p>Panel A. Difference in left ventricular mass/h^2.7 between patients with CKD and the rest of the population. Panel B. Prevalence of ventricular hypertrophy in patients with CKD vs the rest of the population.</p