FIB/SEM and SEM/EDS microstructural analysis of metal-ceramic and zirconia-ceramic interfaces

Recently introduced FIB/SEM analysis in microscopy seems to provide a high-resolution characterization of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution imaging. The aim of this study was to apply the FIB/SEM and SEM/EDS analysis to the interfaces of a metal-ceramic vs. two zirconiaceramic systems. Plate samples of three different prosthetic systems were prepared in the dental lab following the manufacturers’ instructions, where metal-ceramic was the result of a ceramic veneering (porcelain-fused-tometal) and the two zirconia- ceramic systems were produced by the dedicated CAD-CAM procedures of the zirconia cores (both with final sintering) and then veneered by layered or heat pressed ceramics. In a FIB/SEM equipment (also called DualBeam), a thin layer of platinum (1μm) was deposited on samples surface crossing the interfaces, in order to protect them during milling. Then, increasingly deeper trenches were milled by a focused ion beam, first using a relatively higher and later using a lower ion current (from 9 nA to 0.28 nA, 30KV). Finally, FEG-SEM (5KV) micrographs (1000–50,000X) were acquired. In a SEM the analysis of the morphology and internal microstructure was performed by 13KV secondary and backscattered electrons signals (in all the samples). The compositional maps were then performed by EDS probe only in the metal-ceramic system (20kV). Despite the presence of many voids in all the ceramic layers, it was possible to identify: (1) the grain structures of the metallic and zirconia substrates, (2) the thin oxide layer at the metalceramic interface and its interactions with the first ceramic layer (wash technique), (3) the roughness of the two different zirconia cores and their interactions with the ceramic interface, where the presence of zirconia grains in the ceramic layer was reported in two system possibly due to sandblasting before ceramic firing

Waiting times for diagnosis of attention-deficit hyperactivity disorder in children and adolescents referred to Italian ADHD centers must be reduced

BACKGROUND: To investigate timely access to and the time needed to complete the diagnostic path of children and adolescents with suspected attention deficit hyperactivity disorder (ADHD) in the 18 Italian Lombardy Region ADHD reference centers. METHODS: Data of children and adolescents enrolled in the Regional ADHD disease-oriented Registry for suspected ADHD who requested their first visit in 2013-2017 were analyzed. RESULTS: The sample comprised 2262 children and adolescents aged 5-17\u2009years who accessed the ADHD centers for diagnostic classification and management. The median waiting time was of 177\u2009days (range 66-375) from the request for the initial appointment to the completion of the diagnostic path, with a three - fold difference between centers. In addition to the center, the strongest significant predictors of long waiting times were age comorbidities, the severity of the disorder, and having already completed some diagnostic procedures provided by the common standard path. CONCLUSIONS: To guarantee an equal standard of care in ADHD centers for all children and adolescents there is a pressing need to reduce the times to complete the diagnostic path. It is the task of both policymakers and each center to optimize the quality of the service and of the care delivered

Failure to reduce C-reactive protein levels more than 25% in the last 24 hours before intensive care unit discharge predicts higher in-hospital mortality: A cohort study

Purpose: To discharge a patient from the intensive care unit (ICU) is a complex decision-making process because in-hospital mortality after critical illness may be as high as up to 27%. Static C-reactive protein (CRP) values have been previously evaluated as a predictor of post-ICU mortality with conflicting results. Therefore, we evaluated the CRP ratio in the last 24 hours before ICU discharge as a predictor of in-hospital outcomes. Methods: A retrospective cohort study was performed in 409 patients from a 6-bed ICU of a university hospital. Data were prospectively collected during a 4-year period. Only patients discharged alive from the ICU with at least 72 hours of ICU length of stay were evaluated. Results: In-hospital mortality was 18.3% (75/409). Patients with reduction less than 25% in CRP concentrations at 24 hours as compared with 48 hours before ICU discharge had a worse prognosis, with increased mortality (23% vs 11%, P = .002) and post-ICU length of stay (26 [7-43] vs 11 [5-27] days, P = .036). Moreover, among hospital survivors (n = 334), patients with CRP reduction less than 25% were discharged later (hazard ratio, 0.750; 95% confidence interval, 0.602-0.935; P = .011). Conclusions: In this large cohort of critically ill patients, failure to reduce CRP values more than 25% in the last 24 hours of ICU stay is a strong predictor of worse in-hospital outcomes. (C) 2012 Elsevier Inc. All rights reserved

Ranking of aquatic toxicity of esters modelled by QSAR

Alternative methods like predictions based on Quantitative Structure\u2013Activity Relationships (QSARs) are now accepted to fill data gaps and define priority lists for more expensive and time consuming assessments. A heterogeneous data set of 74 esters was studied for their aquatic toxicity, and available experimental toxicity data on algae, Daphnia and fish were used to develop statistically validated QSAR models, obtained using multiple linear regression (MLR) by the OLS (Ordinary Least Squares) method and GA-VSS (Variable Subset Selection by Genetic Algorithms) to predict missing values. An ESter Aquatic Toxicity INdex (ESATIN) was then obtained by combining, by PCA, experimental and predicted toxicity data, from which model outliers and esters highly influential due to their structure had been eliminated. Finally this integrated aquatic toxicity index, defined by the PC1 score, was modelled using only a few theoretical molecular descriptors. This last QSAR model, statistically validated for its predictive power, could be proposed as a preliminary evaluative method for screening/prioritising esters according to their integrated aquatic toxicity, just starting from their molecular structure