High temperature oxidation and embrittlement at 500–600 °C of Ti-6Al-4V alloy fabricated by Laser and Electron Beam Melting

The oxidation kinetics of Ti-6Al-4V alloys fabricated by LBM and EBM, HIP-treated or not, are similar to that of a rolled annealed Ti-6Al-4V alloy, as regards oxide layer and oxygen diffusion layer thickness. Kinetics of oxygen ingress in the metal is independent of the alloy microstructure. At room temperature, the thickness of the brittle layer after a tensile test corresponds to the oxygen diffusion layer, with an oxygen concentration above a critical value that is clearly below 1 at %

Prenatal Isolated Ventricular Septal Defect May Not Be Associated with Trisomy 21

The aim of this study was to examine if isolated fetal ventricular septal defect (VSD) is associated with trisomy 21. One hundred twenty six cases with prenatal VSD diagnosed by a pediatric cardiologist were reviewed. Cases with known risk factors for congenital heart disease, the presence of other major anomalies, soft signs for trisomy 21 or a positive screen test for trisomy 21 were excluded. Ninety two cases formed the study group. None of the cases in the study group had trisomy 21. The upper limit of prevalence for trisomy 21 in isolated VSD is 3%. When prenatal VSD is not associated with other major anomalies, soft markers for trisomy 21 or a positive nuchal translucency or biochemical screen, a decision whether to perform genetic amniocentesis should be individualized. The currently unknown association between isolated VSD and microdeletions and microduplications should be considered when discussing this option