Microhardness and friction coefficient of multi-walled carbon nanotube-yttria-stabilized ZrO2 composites prepared by spark plasma sintering

Multi-walled carbon nanotubes (eight walls) are mixed with an yttria-stabilized ZrO2 powder. The specimens are densified by spark plasma sintering. Compared to ZrO2, there is a 3.8-fold decrease of the friction coefficient against alumina upon the increase in carbon content. Examinations of the friction tracks show that wear is very low when the carbon content is sufficient. Exfoliation of the nanotubes due to shearing stresses and incorporation of the debris into a lubricating film over the contact area is probable

Three dimensional echocardiographic imaging of multiple recurrent myxomas

We report a case of a recurrence of 5 cardiac myxomas in both atria with atypical anatomical features difficult to image. Although a multimodality imaging was performed, three-dimensional echocardiography (3DE) was the only technique able to correctly identify all the recurrences and the anatomical characteristics of the myxomas. MRI detected the blood supply of the mass but even after careful review was able to identify only 4 of the 5 lesions. Even though it was already reported the usefulness of 3DE to better delineate the site of attachment of cardiac tumors, it was never reported its sensibility in the setting of multiple myxomas; this case highlights the ability of the 3DE in this challenging scenario and its potential for being considered the key adjunctive modality for the anatomy when advanced surgical plan is required

Contrast transesophageal three-dimensional echocardiographic imaging for patent foramen ovale: A needful role?

The management of patent foramen ovale (PFO) still remains controversial. According to the newest scientific evidences, the assessment of the PFO size and the shunt has paramount importance for further management [1]. Although two-dimensional (2D) transesophageal (TE) echocardiography (E) contrast study has been considered to be the gold standard imaging modality for diagnosing PFO for a long time, new evidences underscore that its accuracy may have been over-valued [1,2]. Three-dimensional (3D) TEE imaging has emerged as a diagnostic technique that overcome some of the limitations of 2DE. 3D TEE allows an anatomical imaging for a comprehensive echocardiographic assessment of the left atrium, atrial septum and of PFO morphology [3,4]. However, it has never been reported about its diagnostic usefulness in detecting the bubbles passage during contrast study. We report a case where it has been possible to detect the passage of bubbles across the PFO thanks to 3D TEE