Evaluation of the amount of nanoparticles emitted in welding fume from stainless steel using different shielding gases.

The primary objective of this study was to correlate the emission of macro and nanoparticles released during the process of metal inert gas/metal active gas (MIG/MAG) of stainless steel with different gas mixtures. Using different gas mixtures with different heat inputs, it was possible to determine fume formation rates and surface areas of nanoparticles with alveolar lung deposition capacity. It was found, how the various transfer modes and the type of gas protection, in particular, the percentage of active elements in the chemical composition of the gas, affect the amount of fumes generated and also the generation of nanoparticles with a high capacity of deposition. The spray transfer mode always shows higher values of nanoparticles surface area, unlike the fume formation rates. Among the tested mixtures 82%Ar + 18%CO2 generates higher emissions of nanoparticles as well as fume formation rates.

Molecular analysis of a gestation consisting of a complete hydatidiform mole and normal dizygotic twin.

OBJECTIVE: To identify a twin pregnancy consisting of a complete mole and coexistent fetus by means of molecular cytogenetics and DNA polymorphisms. STUDY DESIGN: Seven highly polymorphic DNA markers were used to establish the androgenetic origin of a complete hydatidiform mole that coexisted with a normal 46,XY fetus. Cytogenetic analysis of mole nuclei was performed with centromeric probes, demonstrating a 46,XX constitution. RESULTS: Molar tissue was diploid with two X chromosomes, possibly due to chromosome doubling after monospermic fertilization of an ovum with inactivated or absent nucleus. CONCLUSION: Although contamination with maternal tissue may be difficult to avoid, molecular markers provide the possibility of distinguishing between a complete hydatidiform mole and coexisting normal fetus versus a partial mole, with methods that can be performed antenatally. This distinction is important since in the first case up to 24% of fetuses described in the literature have been viable, and the risk of subsequent development of persistent trophoblastic tumor in patients with a complete mole and a coexisting fetus is considerably higher than in patients with a single, complete hydatidiform mole.