What are the risk factors for admission to the pediatric intensive unit among pediatric patients with COVID-19?

Background: Although with exceptions, evidence seems to indicate that children have lower susceptibility than adults to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. When infected, children generally remain asymptomatic or develop mild disease. A small number of pediatric cases required admission to the pediatric intensive care unit (PICU), respiratory support with a mechanical ventilation and additional life-saving interventions. Even if rarely, death can occur. Aim of this manuscript is to highlight the risk factors associated with severe outcome among pediatric patients with COVID-19. Main findings: Early identification of SARS-CoV-2-infected children at risk of developing severe COVID-19 is vital for service planning, as severely affected pediatric patients require high-quality care and should be followed only where an adequately structured PICU is available. However, early identification of children who must be carefully monitored for substantial risk of severe COVID-19 remains difficult. An underlying comorbidity and heart involvement are frequently observed in severe paediatric cases. Reduced left ventricular systolic function with an ejection fraction < 60%; diastolic dysfunction; and arrhythmias, including ST segment changes, QTc prolongation, and premature atrial or ventricular beat, are the earliest manifestations of heart involvement. Inclusion of heart enzyme serum levels and evaluation of ventricular function among predictive markers could lead to a more effective evaluation of children at risk with proper selection of those to admit to the PICU and with more adequate treatment in case of more severe clinical manifestations. Conclusions: To appropriately manage severe pediatric COVID-19 cases, greater attention should be paid to risk factors in children and adolescents, especially to cardiovascular alterations (e.g., heart enzyme serum levels and evaluation of ventricular function). Further studies are needed and the development of a validated score based on all the most common presumed markers of disease severity seems essential

Thermal conductivity of clay bricks

In the present work the thermal conductivity of 29 samples of clay bricks was measured and the correlations of the thermal performance with the compositional, physical, and microstructural features of products were investigated. The results obtained directed our attention toward a better understanding of the role played by some parameters (i.e., mineralogical components and pore size distribution), other than bulk density, in improving or depressing the insulating properties of bricks. Among them, the unfavorable role of quartz, Ca-rich silicates, and amorphous phase came out, while the role of pore size and specific surface should be more accurately evaluated in the structural design of materials

Plasmons and Coulomb drag in Dirac/Schroedinger hybrid electron systems

We show that the plasmon spectrum of an ordinary two-dimensional electron gas (2DEG) hosted in a GaAs heterostructure is significantly modified when a graphene sheet is placed on the surface of the semiconductor in close proximity to the 2DEG. Long-range Coulomb interactions between massive electrons and massless Dirac fermions lead to a new set of optical and acoustic intra-subband plasmons. Here we compute the dispersion of these coupled modes within the Random Phase Approximation, providing analytical expressions in the long-wavelength limit that shed light on their dependence on the Dirac velocity and Dirac-fermion density. We also evaluate the resistivity in a Coulomb-drag transport setup. These Dirac/Schroedinger hybrid electron systems are experimentally feasible and open new research opportunities for fundamental studies of electron-electron interaction effects in two spatial dimensions.Comment: 7 pages, 4 figure

Linear response of doped graphene sheets to vector potentials

A two-dimensional gas of massless Dirac fermions (MDFs) is a very useful model to describe low-energy electrons in monolayer graphene. Because the MDF current operator is directly proportional to the (sublattice) pseudospin operator, the MDF current-current response function, which describes the response to a vector potential, happens to coincide with the pseudospin-pseudospin response function. In this work we present analytical results for the wavevector- and frequency-dependent longitudinal and transverse pseudospin-pseudospin response functions of noninteracting MDFs. The transverse response in the static limit is then used to calculate the noninteracting orbital magnetic susceptibility. These results are a starting point for the construction of approximate pseudospin-pseudospin response functions that would take into account electron-electron interactions (for example at the random-phase-approximation level). They also constitute a very useful input for future applications of current-density-functional theory to graphene sheets subjected to time- and spatially-varying vector potentials.Comment: 11 pages, 5 figures, submitte

Depth profiling of melting and metallization in Si(111) and Si(001) surfaces

International audienc

The cost of inflammatory bowel disease management matches with clinical course: A single outpatient centre analysis

Inflammatory bowel diseases (IBD) have a large economic burden on health systems. Our single-centre observational retrospective study aimed to assess an economic evaluation in two IBD outpatient cohorts (biological and conventional therapy) in relation to disease activity within a three-year follow-up. Four hundred and seventeen consecutive IBD patients referred to our tertiary gastroenterology unit (Bari-Puglia-Southern Italy) on January 2014–December 2016 were included. For each group (conventional/biological), we assessed direct/indirect costs and clinical/endoscopic activity within the first year and along the three-year follow-up. Statistical analyses: Wilcoxon signed-rank test (continuous variables), chi-square and Fisher’s test (categorical variables), Spearman ranks (single outcome) and ANOVA (detection time, clinical/endoscopic scores) were used. Continuous variables were expressed as mean ± standard deviation and range and/or median, interquartile range and range; categorical variables were expressed as proportions with 95% confidence interval. Direct and indirect cost items of 2014 and 2014–2016 were higher in patients treated with biological than conventional therapy. Subjects on biological therapy were younger and showed clinical and endoscopic moderate-to-severe disease activity. After three years, they reached a significant improvement from baseline. Conversely, disease activity was mild when conventional treatment had a beneficial effect. In conclusion, overall IBD management cost matches with clinical course and needs long-term evaluation in critical patients